JP2020106427A - Physical quantity measurement device - Google Patents

Abstract

To provide a physical quantity measurement device that can increase the measurement accuracy of the physical quantity.SOLUTION: In a housing 21, a measurement flow path 32 is branched from a passage flow path 31. The passage flow path 31 has a passage inlet 33 and a passage outlet 34. The measurement flow path 32 has a measurement inlet 35 and a measurement outlet 36. The passage flow path 31 has an inlet passage path 331 and the inlet passage path 331 extends from the passage inlet 33 to the passage outlet 34. The inner surface of the housing 21 has an inlet ceiling surface 342 and an inlet floor surface 346. The inlet ceiling surface 342 extends from the passage inlet 33 to the measurement inlet 35, and the inlet floor surface 346 is opposed to the inlet ceiling surface 342 across the inlet passage path 331. The inlet ceiling surface 342 is inclined with respect to the inlet floor surface 346 so that the distance H21 between the inlet ceiling surface 342 and the inlet floor surface 346 decreases gradually toward the passage outlet 34 from the passage inlet 33.SELECTED DRAWING: Figure 41

Description

The disclosure of this specification relates to a physical quantity measuring device.

As a physical quantity measuring device for measuring a physical quantity of a fluid, for example, Patent Document 1 discloses a flow meter having a sub passage for taking in a part of air flowing in the main passage and a casing forming the sub passage. The sub passage has a first passage and a second passage branched from the first passage, and a flow rate detecting unit for detecting the flow rate of air is provided in the second passage. In the sub passage, the air flows from the main intake port into the first passage, and the air flowing in the first passage flows from the sub intake port into the second passage. The first passage has an upstream passage extending from the main intake port toward the sub-intake port, and the upstream passage is in a direction inclined with respect to the air flow direction in the main passage. It is extended.

JP, 2005-68794, A

In Patent Document 1, the inner surface of the casing forms an upstream passage. On this inner surface, the surface that extends over the main intake port and the upstream end of the second passage is called the ceiling surface, and the surface that faces the ceiling surface through the upstream passage is called the floor surface. The surface and the floor surface are inclined with respect to the flow direction in accordance with the upstream passage. In the configuration in which the ceiling surface and the floor surface extend parallel to each other, among the air flowing into the first passage from the main intake port, the air flowing along one of the ceiling surface and the floor surface and the air flowing along the other The flowing air tends to travel parallel to each other in the upstream passage. Depending on the direction of the air flowing into the first passage from the main inlet, the air that should flow along one of the ceiling surface and the floor surface may separate from one surface and cause turbulence such as vortex. I'm worried.

In this case, due to the turbulence caused by the separation of the air from one surface of the ceiling surface and the floor surface, the air flowing along the other surface also easily becomes turbulent. As described above, when the air flowing through the first passage is disturbed, the air flowing from the first passage into the second passage is disturbed, and the flow rate detection accuracy of the flow rate detection unit is likely to decrease. Therefore, the accuracy of detecting a physical quantity such as the flow rate of a fluid such as air decreases, and the measurement accuracy of the physical quantity measuring device decreases.

A main object of the present disclosure is to provide a physical quantity measuring device capable of increasing the measurement accuracy of a physical quantity.

In order to achieve the above object, the disclosed aspects are
A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A passage channel (31) having a passage inlet (33) into which the fluid flows, and a passage outlet (34) from which the fluid introduced from the passage inlet flows out;
A measurement flow path (32) branched from the passage flow path for measuring the physical quantity of the fluid, the measurement flow path being provided between the passage entrance and the passage exit and having the measurement flow inlet (35) into which the fluid flows. A measurement flow path (32) having a measurement outlet (36) through which the fluid flowing from the measurement inlet flows out;
A physical quantity sensor (22) provided in the measurement flow path for detecting the physical quantity of the fluid;
A housing (21) forming a passage and a measurement passage,
Equipped with
The inner surface of the housing is
An inlet passage that forms an inlet passage (331) that extends over the passage inlet and the measurement inlet of the passage passage and that extends over the passage inlet and the measurement inlet in the direction (Z) in which the passage inlet and the passage outlet are aligned. The ceiling surface (342),
An entrance floor surface (346) that forms an entrance passage and faces the entrance ceiling surface through the entrance passage;
Has
The entrance ceiling surface is
The ceiling inclined surface (342, which is inclined with respect to the entrance floor surface such that the distance (H21) from the entrance floor surface gradually decreases from the passage entrance toward the passage exit and extends from the passage entrance toward the measurement entrance (342, 342a) is a physical quantity measuring device.

According to the first aspect, in the entrance passage of the passage passage, the ceiling inclined surface is inclined with respect to the entrance floor surface so as to gradually approach the entrance floor surface from the passage entrance toward the passage exit. With this configuration, of the fluid that has flowed from the passage inlet to the inlet passage, the fluid that has flowed to the ceiling slope surface side can change its direction of travel due to the ceiling slope surface, and can easily travel along the ceiling slope surface toward the entrance floor surface. Become. Therefore, even if the fluid that should flow along the inlet floor surface peels off or tends to peel off from the inlet floor surface, the fluid that peels off or tends to peel off along the sloped surface of the ceiling. The fluid advancing toward the inlet floor is pressed against the inlet floor. In this case, the fluid separating from the inlet floor surface and causing turbulence such as vortex is regulated by the fluid flowing along the inclined surface of the ceiling, and as a result, the fluid turbulence hardly occurs in the inlet passage. Therefore, the detection accuracy of the physical quantity by the physical quantity sensor can be increased, and by extension, the measurement accuracy of the physical quantity by the physical quantity measurement device can be increased.

It should be noted that the claims and the reference numerals in parentheses described in this section merely show the corresponding relationship with the specific means described in the embodiments described later, and do not limit the technical scope of the present disclosure. Absent.

The figure which shows the structure of the combustion system in 1st Embodiment. The front view of the air flow meter in the state attached to the intake pipe. The top view of the air flow meter attached to the intake pipe. The perspective view of the air flow meter seen from the passage entrance side. The perspective view of the air flow meter seen from the passage exit side. The side view which looked at the air flow meter from the connector side. The side view which looked at the air flow meter from the opposite side to the connector part. VIII-VIII sectional view taken on the line of FIG. 3 is a perspective view of the sensor SA in the configuration group A. FIG. The top view of sensor SA seen from the mold surface side. The top view of sensor SA seen from the mold back side. The perspective view of a flow sensor. The figure which shows the wiring pattern of a membrane part. The longitudinal cross-sectional view of an air flow meter. The XV-XV sectional view taken on the line of FIG. XVI-XVI sectional view taken on the line of FIG. FIG. 6 is a vertical cross-sectional view of an air flow meter around a housing partition in configuration group B. The figure which shows the state before attaching the sensor SA to a housing. FIG. 4 is a plan view of the housing before the sensor SA is assembled. The figure which shows the state before the sensor SA deform|transforms a housing partition part. The figure which shows the state after the sensor SA deform|transforms the housing partition part. FIG. 6 is a vertical cross-sectional view of an air flow meter in configuration group D. FIG. 23 is an enlarged view around the sensor path of FIG. 22. The XXIV-XXIV sectional view taken on the line of FIG. FIG. 25 is an enlarged view around the sensor path of FIG. 24. FIG. 6 is a vertical cross-sectional view of the air flow meter in the configuration group E, which is an enlarged view of the vicinity of the sensor path. FIG. 4 is a cross-sectional view of the air flow meter, which is an enlarged view around the sensor path. The schematic front view of the air flow meter in the structural group H. The perspective view of a connection terminal. The top view of a connection terminal. FIG. 29 is a cross-sectional view taken along line XXXI-XXXI of FIG. 28. The XXXII-XXXII sectional view taken on the line of FIG. The side view of the air flow meter in the state where it was attached to the intake pipe in a 2nd embodiment. The front view of an air flow meter. FIG. 34 is a sectional view taken along line XXXV-XXXV of FIG. 33. 35 is a sectional view taken along line XXXVI-XXXVI of FIG. 35 in the configuration group B. FIG. FIG. 36 is an enlarged view around the sensor SA of FIG. 35. FIG. 36 is an exploded sectional view of the base member, the cover member, and the sensor SA in FIG. 35. FIG. 4 is an enlarged view of the vicinity of the sensor SA of BH6. The longitudinal cross-sectional view of the air flow meter in the third embodiment and the configuration group C. FIG. 41 is an enlarged view around the passage channel of FIG. 40. The figure for demonstrating the cross-sectional area of an inlet passage part. The figure for demonstrating the mainstream which flowed into the passage. The figure for demonstrating the downward drift which flowed into the passage. The figure for demonstrating the upward drift which flowed into the passage. The figure which shows the relationship between the inclination angle of the entrance ceiling surface with respect to the main streamline, and the output fluctuation of an air flow meter. The figure which shows the change aspect of a flow volume. The figure which shows the relationship between a pulsation characteristic and an amplitude ratio. The figure for demonstrating the structure from which a branch angle differs. The figure which shows the relationship between a bifurcation angle and a pulsation characteristic. The longitudinal cross-sectional view of the air flow meter of the housing partition part periphery of 1st Embodiment in the modification B1. Sectional drawing of the air flow meter of the housing partition part periphery of 2nd Embodiment in the modification B2. FIG. 3 is an exploded cross-sectional view of a base member, a cover member, and a sensor SA. FIG. 11 is a vertical cross-sectional view of an air flow meter around a housing partition section according to the first embodiment in Modification B4. Sectional drawing of the air flow meter of the housing partition part periphery of 2nd Embodiment in the modification B5. FIG. 3 is an exploded cross-sectional view of a base member, a cover member, and a sensor SA. Sectional drawing of the air flow meter of the housing partition part periphery of 2nd Embodiment in the modification B6. FIG. 3 is an exploded cross-sectional view of a base member, a cover member, and a sensor SA. The longitudinal cross-sectional view of the air flow meter of the housing partition part periphery of 1st Embodiment in the modification B7. FIG. 11 is a vertical cross-sectional view of an air flow meter around a passage passage according to a third embodiment in modification C1. FIG. 9 is a vertical cross-sectional view of an air flow meter around a passage passage according to a third embodiment in modification C2. FIG. 11 is a vertical cross-sectional view of an air flow meter around a passage passage according to a third embodiment in modification C3. The longitudinal cross-sectional view of the air flow meter about 1st Embodiment in the modification D1. The transverse cross-sectional view of the air flow meter for the first embodiment in modification D14.

Hereinafter, a plurality of embodiments of the present disclosure will be described with reference to the drawings. In addition, in each embodiment, the corresponding components may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each embodiment, the configurations of the other examples described above can be applied to the other parts of the configuration. Further, not only the combination of the configurations explicitly described in the description of each embodiment, but the configuration of a plurality of embodiments can be partially combined even if they are not explicitly described, unless the combination causes any trouble. Then, a combination in which the configurations described in the plurality of embodiments and the modifications are not explicitly disclosed is also disclosed by the following description.

(First embodiment)
The combustion system 10 shown in FIG. 1 has an internal combustion engine 11 such as a gasoline engine, an intake passage 12, an exhaust passage 13, an air flow meter 20, and an ECU 15, and is mounted on, for example, a vehicle. The air flow meter 20 is provided in the intake passage 12, and measures physical quantities such as the flow rate of intake air supplied to the internal combustion engine 11, temperature, humidity, and pressure. The air flow meter 20 is a flow rate measurement device that measures the flow rate of air, and corresponds to a physical quantity measurement device that measures a fluid such as intake air. The intake air is a gas supplied to the combustion chamber 11a of the internal combustion engine 11. In the combustion chamber 11a, a mixture of intake air and fuel is ignited by the spark plug 17.

The ECU (Engine Control Unit) 15 is a control device that controls the operation of the combustion system 10. The ECU 15 is an arithmetic processing circuit including a processor, a storage medium such as a RAM, a ROM and a flash memory, and a microcomputer including an input/output unit, a power supply circuit, and the like. Sensor signals output from the air flow meter 20, sensor signals output from many on-vehicle sensors, and the like are input to the ECU 15. The ECU 15 controls the engine with respect to the fuel injection amount of the injector 16 and the EGR amount using the measurement result of the air flow meter 20. The ECU 15 is a control device that controls the operation of the internal combustion engine 11, and the combustion system 10 can also be referred to as an engine control system. The ECU 15 corresponds to an external device.

The ECU 15 may also be called an electronic control unit. The controller or the control system is provided by (a) an algorithm as a plurality of logics called if-then-else form, or (b) a trained model tuned by machine learning, for example, an algorithm as a neural network. ..

The controller is provided by a control system including at least one computer. The control system may include multiple computers linked by a data communication device. The computer includes at least one processor (hardware processor) that is hardware. The hardware processor can be provided by (i), (ii), or (iii) below.

(I) The hardware processor may be at least one processor core that executes a program stored in at least one memory. In this case, the computer is provided with at least one memory and at least one processor core. The processor core is called CPU: Central Processing Unit, GPU: Graphics Processing Unit, RISC-CPU, or the like. The memory is also called a storage medium. A memory is a non-transitional and tangible storage medium that stores "programs and/or data" readable by a processor in a non-transitory manner. The storage medium is provided by a semiconductor memory, a magnetic disk, an optical disk, or the like. The program may be distributed by itself or as a storage medium in which the program is stored.

(Ii) The hardware processor may be a hardware logic circuit. In this case, the computer is provided by a digital circuit including a large number of programmed logic units (gate circuits). The digital circuit is also called a logic circuit array, for example, ASIC: Application-Specific Integrated Circuit, FPGA: Field Programmable Gate Array, PGA: Programmable Gate Array, CPLD: Complex Programmable Logic Device. The digital circuit may include a memory that stores programs and/or data. The computer may be provided by analog circuitry. The computer may be provided by a combination of digital circuits and analog circuits.

(Iii) The hardware processor may be a combination of (i) and (ii) above. (I) and (ii) are arranged on different chips or on a common chip. In these cases, the part (ii) is also called an accelerator.

The control device, the signal source, and the controlled object provide various elements. At least some of these elements can be referred to as blocks, modules, or sections. Furthermore, elements included in the control system are referred to as functional means only if they are intentional.

The control unit and the method described in this disclosure are realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. May be done. Alternatively, the control unit and the method described in this disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method described in this disclosure include a processor and a memory programmed to perform one or more functions and a processor configured with one or more hardware logic circuits. It may be realized by one or more dedicated computers configured by combination. Further, the computer program may be stored in a computer-readable non-transition tangible recording medium as an instruction executed by the computer.

The combustion system 10 has a plurality of measurement units as in-vehicle sensors. As the measurement unit, in addition to the air flow meter 20, there are a throttle sensor 18a, an air-fuel ratio sensor 18b, and the like. Each of these measuring units is electrically connected to the ECU 15 and outputs a detection signal to the ECU 15. The air flow meter 20 is provided in the intake passage 12 downstream of the air cleaner 19 and upstream of the throttle valve to which the throttle sensor 18a is attached. The air cleaner 19 has an air case forming a part of the intake passage 12 and an air filter for removing foreign matters such as dust from the intake air, and the air filter is attached to the air case.

As shown in FIG. 2, FIG. 3, and FIG. 8, the air flow meter 20 is attached to the piping unit 14 as an attachment target. The piping unit 14 has an intake pipe 14a, a pipe flange 14c, and a pipe boss 14d, and is a forming member that forms the intake passage 12. The piping unit 14 forms at least a part of an air case, for example. In the configuration in which the piping unit 14 forms an air case, an air filter is attached to the piping unit 14 in addition to the air flow meter 20. In the piping unit 14, the intake pipe 14a, the pipe flange 14c, and the pipe boss 14d are formed of a resin material or the like.

The intake pipe 14a is a pipe such as a duct that forms the intake passage 12. The intake pipe 14a is provided with an airflow insertion hole 14b as a through hole penetrating the outer peripheral portion thereof. The pipe flange 14c is formed in an annular shape and extends along the peripheral edge of the airflow insertion hole 14b. The pipe flange 14c extends from the outer surface of the intake pipe 14a toward the side opposite to the intake passage 12. The tube boss 14d is a columnar member, and is a support portion that supports the air flow meter 20. The pipe boss 14d extends from the outer surface of the intake pipe 14a along the pipe flange 14c, and is provided in plurality (for example, two) on the intake pipe 14a. In this embodiment, both the pipe flange 14c and the pipe boss 14d extend in the height direction Y from the intake pipe 14a.

The air flow meter 20 is inserted into the pipe flange 14c and the air flow insertion hole 14b to enter the intake passage 12, and is fixed to the pipe boss 14d by a fixing tool such as a bolt in this state. The air flow meter 20 is not in contact with the tip surface of the tube flange 14c, but is in contact with the tip surface of the tube boss 14d. Therefore, the relative position and angle of the air flow meter 20 with respect to the piping unit 14 are set by the pipe boss 14d instead of the pipe flange 14c. The tip surfaces of the plurality of tube bosses 14d are flush with each other. Note that the tube boss 14d is not shown in FIG.

In this embodiment, the width direction X, the height direction Y, and the depth direction Z are set for the air flow meter 20, and these directions X, Y, and Z are orthogonal to each other. The air flow meter 20 extends in the height direction Y, and the intake passage 12 extends in the depth direction Z. The air flow meter 20 has an entrance portion 20a that has entered the intake passage 12 and an extrusion portion 20b that does not enter the intake passage 12 and that protrudes to the outside from the pipe flange 14c. Are arranged in the height direction Y.

As shown in FIGS. 2, 4, 7, and 8, the air flow meter 20 includes a housing 21, a flow rate sensor 22 that detects the flow rate of intake air, and an intake air temperature sensor 23 that detects the temperature of intake air. Have The housing 21 is made of, for example, a resin material. The flow rate sensor 22 is housed inside the housing 21. In the air flow meter 20, since the housing 21 is attached to the intake pipe 14a, the flow rate sensor 22 can come into contact with the intake air flowing through the intake passage 12.

The housing 21 is attached to the piping unit 14 as an attachment target. On the outer surface of the housing 21, of the pair of end surfaces 21a and 21b arranged in the height direction Y, the one included in the entering portion 20a is referred to as the housing distal end surface 21a, and the one included in the protruding portion 20b is the housing base. It is referred to as the end face 21b. The housing front end surface 21a and the housing base end surface 21b are orthogonal to the height direction Y. The tip surface of the pipe flange 14c is also orthogonal to the height direction Y. Note that the attachment target to which the air flow meter 20 and the housing 21 are attached need not be the piping unit 14 as long as it is a forming member that forms the intake passage 12.

On the outer surface of the housing 21, a surface arranged on the upstream side of the intake passage 12 is referred to as a housing upstream surface 21c, and a surface arranged on the opposite side of the housing upstream surface 21c is referred to as a housing downstream surface 21d. In addition, one of a pair of surfaces facing each other with the housing upstream surface 21c and the housing base end surface 21b is referred to as a housing front surface 21e, and the other is referred to as a housing rear surface 21f. The housing surface 21e is a surface on the side where the flow rate sensor 22 is provided in the sensor SA50 described later.

Regarding the housing 21, in the height direction Y, the housing front end surface 21a side may be referred to as the housing front end side, and the housing base end surface 21b side may be referred to as the housing base end side. In the depth direction Z, the housing upstream surface 21c side may be referred to as the housing upstream side, and the housing downstream surface 21d side may be referred to as the housing downstream side. Further, in the width direction X, the housing front surface 21e side may be referred to as the housing front side, and the housing back surface 21f side may be referred to as the housing back side.

As shown in FIGS. 2 to 7, the housing 21 has a seal holding portion 25, a flange portion 27, and a connector portion 28. The air flow meter 20 has a seal member 26, and the seal member 26 is attached to the seal holding portion 25.

The seal holding portion 25 is provided inside the pipe flange 14c and holds the seal member 26 so as not to be displaced in the height direction Y. The seal holding portion 25 is included in the entry portion 20 a of the air flow meter 20. The seal holding portion 25 has a holding groove portion 25 a that holds the seal member 26. The holding groove portion 25a extends in directions X and Z orthogonal to the height direction Y, and makes one round around the housing 21. The seal member 26 is a member such as an O-ring that seals the intake passage 12 inside the pipe flange 14c. The seal member 26 is in a state of entering the inside of the holding groove portion 25a, and is in close contact with both the inner surface of the holding groove portion 25a and the inner peripheral surface of the pipe flange 14c. The portion where the seal member 26 and the inner surface of the holding groove portion 25a are in close contact with each other and the portion where the seal member 26 and the inner peripheral surface of the flange 14c are in close contact with each other form a ring around the housing 21.

The flange portion 27 is formed with a fixing hole such as a screw hole for fixing a fixing tool such as a screw for fixing the housing 21 to the intake pipe 14a. In this embodiment, the fixing holes are, for example, the flange holes 611 and 612, and the fixing tools are screws. Note that, in FIG. 3, the screws inserted into the flange holes 611 and 612 are not shown.

The surface of the flange portion 27 on the front end side of the housing is in contact with the front end surface of the tube boss 14d in a state of being overlapped with each other, and this overlapped portion is referred to as an angle setting surface 27a. Both the angle setting surface 27a and the tip end surface of the tube boss 14d extend in a direction orthogonal to the height direction Y, and extend in the width direction X and the depth direction Z. The tip end surface of the pipe boss 14d sets the relative position and angle of the angle setting surface 27a with respect to the intake pipe 14a. The angle setting surface 27a sets the relative position or angle of the housing 21 with respect to the intake pipe 14a in the air flow meter 20.

In the intake pipe 14 a of the piping unit 14, the main flow that mainly flows of the air flowing through the intake passage 12 proceeds in the depth direction Z. When the direction in which the mainstream proceeds is called the mainstream direction, the depth direction Z is the mainstream direction. In the housing 21, the angle setting surface 27a of the flange portion 27 extends in the mainstream direction and the depth direction Z. The tip surface of the tube boss 14d also extends in the mainstream direction and the depth direction Z.

The connector portion 28 is a protection portion that protects the connector terminal 28 a electrically connected to the flow rate sensor 22. The connector terminal 28a is electrically connected to the ECU 15 by connecting the electrical wiring extending from the ECU 15 to the connector portion 28 via the plug portion. The flange portion 27 and the connector portion 28 are included in the protruding portion 20b of the air flow meter 20.

As shown in FIGS. 2, 4, and 7, the intake air temperature sensor 23 is provided outside the housing 21. The intake air temperature sensor 23 is a temperature sensitive element that senses the temperature of intake air, and is provided on the rear surface 21f of the housing. To the intake air temperature sensor 23, a lead wire 23a formed by wiring or the like is connected. The housing 21 has an intake air temperature support portion 618. The intake air temperature support portion 618 is a convex portion provided on the back surface 21f of the housing, and protrudes toward the back side of the housing from the intake air temperature sensor 23 in the width direction X. The intake air temperature support portion 618 supports the intake air temperature sensor 23 by supporting the lead wire 23a. The intake air temperature support portion 618 is provided closer to the housing base end side than the intake air temperature sensor 23 in the height direction Y. The lead wire 23a extends from the intake air temperature support portion 618 toward the front end side of the housing.

The lead wire 23a penetrates the intake air temperature support portion 618 in the height direction Y. At the time of manufacturing the air flow meter 20, a through hole is formed in the intake air temperature support portion 618 so as to penetrate the intake air temperature support portion 618 in the height direction Y. Then, with the lead wire 23a inserted through the through hole, the intake temperature support portion 618 is crushed in the width direction X to crush the through hole, and the lead wire 23a inserted through the through hole is supported for intake temperature. It is embedded in the portion 618. In this case, the distal end surface of the intake air temperature support portion 618 is crushed while being heated by a heating tool such as a heater so that the intake air temperature support portion 618 is thermally deformed, and the lead wire 23a is deformed at a portion of the intake air temperature support portion 618 that is thermally deformed. Hold it over. This work can also be called heat staking.

As shown in FIG. 8, the housing 21 has a bypass flow passage 30. The bypass flow passage 30 is provided inside the housing 21, and is formed by at least a part of the internal space of the housing 21. The inner surface of the housing 21 forms the bypass flow passage 30 and is a forming surface.

The bypass flow passage 30 is arranged in the entry portion 20 a of the air flow meter 20. The bypass flow passage 30 has a passage flow passage 31 and a measurement flow passage 32. The measurement flow path 32 is in a state where the flow rate sensor 22 and its surrounding portion of the sensor SA50 described later are inserted. The passage 31 is formed by the inner surface of the housing 21. The measurement flow path 32 is formed by the outer surface of a part of the sensor SA50 in addition to the inner surface of the housing 21. The intake passage 12 may be referred to as a main passage and the bypass passage 30 may be referred to as a sub passage.

The passage channel 31 penetrates the housing 21 in the depth direction Z. The passage channel 31 has a passage inlet 33 which is an upstream end thereof and a passage outlet 34 which is a downstream end thereof. The measurement flow channel 32 is a branch flow channel branched from the intermediate portion of the passage flow channel 31, and the flow rate sensor 22 is provided in the measurement flow channel 32. The measurement flow path 32 has a measurement inlet 35 which is an upstream end thereof and a measurement outlet 36 which is a downstream end thereof. The part where the measurement flow path 32 branches from the passage flow path 31 is a boundary portion between the passage flow path 31 and the measurement flow path 32, and the measurement inlet 35 is included in this boundary portion. In addition, the boundary between the passage channel 31 and the measurement channel 32 can be referred to as a channel boundary. The measurement inlet 35 faces the front end side of the housing while being inclined so as to face the measurement outlet 36 side.

The measurement flow channel 32 extends from the passage flow channel 31 toward the base end side of the housing. The measurement flow path 32 is provided between the passage flow path 31 and the housing base end surface 21b. The measurement flow path 32 is curved so that the portion between the measurement inlet 35 and the measurement outlet 36 bulges toward the base end side of the housing. The measurement flow path 32 has a curved portion that bends continuously, a bent portion that bends in a stepwise manner, and a portion that extends straight in the height direction Y and the depth direction Z.

The flow rate sensor 22 is a thermal type flow rate detection unit having a heater unit. The flow rate sensor 22 outputs a detection signal according to the temperature change when the temperature change occurs due to the heat generation of the heater unit. The flow rate sensor 22 is a rectangular parallelepiped chip component, and the flow rate sensor 22 can also be referred to as a sensor chip. The flow rate sensor 22 can also be referred to as a physical quantity sensor or a physical quantity detection unit that detects the flow rate of intake air as a physical quantity of a fluid.

The air flow meter 20 has a sensor subassembly including a flow rate sensor 22, and this sensor subassembly is referred to as a sensor SA50. The sensor SA50 is embedded in the housing 21 in a state where a part of the sensor SA50 enters the measurement flow channel 32. In the air flow meter 20, the sensor SA50 and the bypass flow passage 30 are arranged in the height direction Y. Specifically, the sensor SA50 and the passage channel 31 are arranged in the height direction. The sensor SA50 corresponds to the detection unit. The sensor SA50 can also be called a measurement unit or a sensor package.

<Explanation of configuration group A>
As shown in FIGS. 9, 10, and 11, the sensor SA50 has a sensor support portion 51 in addition to the flow rate sensor 22. The sensor support portion 51 is attached to the housing 21 and supports the flow rate sensor 22. The sensor support portion 51 has an SA substrate 53 and a mold portion 55. The SA substrate 53 is a substrate on which the flow sensor 22 is mounted, and the mold portion 55 covers at least a part of the flow sensor 22 and at least a part of the SA substrate 53. The SA substrate 53 can also be called a lead frame.

The mold part 55 is formed in a plate shape as a whole. On the outer surface of the mold portion 55, of the pair of end surfaces 55a and 55b arranged in the height direction Y, the housing front end side is referred to as the mold front end surface 55a, and the housing base end side is referred to as the mold base end surface 55b. .. The mold tip surface 55a is the tip portion of the mold portion 55 and the sensor support portion 51 and corresponds to the support tip portion. The mold portion 55 corresponds to the protective resin portion.

On the outer surface of the mold portion 55, one of a pair of surfaces provided with the mold front end surface 55a and the mold base end surface 55b interposed therebetween is referred to as a mold upstream surface 55c, and the other is referred to as a mold downstream surface 55d. In FIG. 8, the sensor SA50 has the interior of the housing 21 with the mold front end surface 55a disposed on the airflow front end side and the mold upstream surface 55c disposed upstream of the measurement flow path 32 relative to the mold downstream surface 55d. It is installed in. In the sensor support portion 51, the mold upstream surface 55c corresponds to the upstream end portion, and the mold downstream surface 55d corresponds to the downstream end portion.

The mold upstream surface 55c of the sensor SA50 is arranged on the upstream side of the mold downstream surface 55d in the measurement flow path 32. In the portion of the measurement flow path 32 where the flow rate sensor 22 is provided, the direction of air flow is opposite to the direction of air flow in the intake passage 12. Therefore, the mold upstream surface 55c is arranged on the downstream side of the mold downstream surface 55d in the intake passage 12. The air flowing along the flow rate sensor 22 flows in the depth direction Z, and the depth direction Z can also be referred to as a flow direction.

As shown in FIGS. 9 and 10, in the sensor SA50, the flow rate sensor 22 is exposed on one surface side of the sensor SA50. On the outer surface of the mold part 55, the plate surface on the side where the flow rate sensor 22 is exposed is referred to as a mold surface 55e, and the plate surface on the opposite side is referred to as a mold back surface 55f. One plate surface of the sensor SA50 is formed by the mold surface 55e, the mold surface 55e corresponds to the support surface, and the mold back surface 55f corresponds to the support back surface.

Regarding the mold portion 55, in the height direction Y, the mold front end surface 55a side may be referred to as the mold side, and the mold base end surface 55b side may be referred to as the mold base end side. In the depth direction Z, the mold upstream surface 55c side may be referred to as the mold upstream side, and the mold downstream surface 55d side may be referred to as the mold downstream side. Furthermore, in the width direction X, the mold front surface 55e side may be referred to as the mold front side, and the mold back surface 55f side may be referred to as the mold back side.

The SA substrate 53 is formed of a metal material or the like in a plate shape as a whole, and is a conductive substrate. The plate surface of the SA substrate 53 is orthogonal to the width direction X and extends in the height direction Y and the depth direction Z. The flow rate sensor 22 is mounted on the SA substrate 53. The SA substrate 53 has a lead terminal 53a, an upstream test terminal 53b, and a downstream test terminal 53c. The SA substrate 53 has a portion covered by the mold portion 55 and a portion not covered by the mold portion 55, and terminals 53a, 53b, 53c are formed by the uncovered portion. .. Note that the terminals 53a, 53b, 53c are not shown in FIG. 8 and the like.

The lead terminals 53a are terminals protruding in the height direction Y from the mold base end surface 55b, and a plurality of lead terminals 53a are provided. The lead terminals 53a include terminals connected to the connector terminals 28a, terminals connected to the intake air temperature sensor 23, and adjustment terminals for adjusting the detection accuracy of the flow rate sensor 22 and the like. In the present embodiment, the sensor SA50 has six lead terminals 53a. These six lead terminals 53a include three terminals connected to the connector terminal 28a, two terminals connected to the intake air temperature sensor 23, and one adjustment terminal. The three terminals connected to the connector terminal 28a include a ground terminal grounded to the ground, a power supply terminal to which a predetermined voltage such as 5V is applied, and an output terminal that outputs a signal related to the detection result of the flow rate sensor 22. include. The two terminals connected to the intake air temperature sensor 23 include a ground terminal connected to the ground and an output terminal for outputting a signal regarding the detection result of the intake air temperature sensor 23.

The upstream test terminals 53b are terminals protruding in the depth direction Z from the mold upstream surface 55c, and a plurality of them are provided. For the upstream test terminals 53b, a capacitor check terminal for confirming the operation of a capacitor mounted on the SA substrate 53, an IC test terminal for confirming the operation of the flow sensor 22, and grounding to the ground. The ground terminal of is included.

The downstream test terminals 53c are terminals protruding in the depth direction Z from the mold downstream surface 55d, and a plurality of them are provided. Similar to the upstream test terminal 53b, the plurality of downstream test terminals 53c include a capacitor check terminal, an IC test terminal, and a ground terminal.

As shown in FIG. 12, the flow rate sensor 22 is formed in a plate shape as a whole. The flow rate sensor 22 has a sensor surface 22a, which is one surface, and a sensor back surface 22b opposite to the sensor surface 22a. In the flow rate sensor 22, the sensor back surface 22b is overlaid on the SA substrate 53, and a part of the sensor surface 22a is exposed to the outside of the sensor SA50.

The flow rate sensor 22 has a sensor concave portion 61 and a membrane portion 62. The sensor concave portion 61 is provided on the sensor back surface 22b, and the membrane portion 62 is provided on the sensor surface 22a. The membrane portion 62 forms a sensor concave bottom surface 501 which is the bottom surface of the sensor concave portion 61. The portion of the membrane portion 62 forming the sensor concave bottom surface 501 is the bottom portion for the sensor concave portion 61. The sensor recess 61 is formed by recessing the sensor back surface 22b toward the sensor front surface 22a. The sensor recess opening 503 which is the opening of the sensor recess 61 is provided on the sensor back surface 22b. The sensor recess inner wall surface 502, which is the inner wall surface of the sensor recess 61, extends across the sensor recess bottom surface 501 and the sensor recess opening 503. The membrane portion 62 is a sensing portion that senses the flow rate.

The flow rate sensor 22 has a sensor substrate 65 and a sensor film portion 66. The sensor substrate 65 is a base material of the flow rate sensor 22, and is formed in a plate shape from a semiconductor material such as silicon. The sensor substrate 65 has a sensor substrate front surface 65a, which is one surface, and a sensor substrate back surface 65b opposite to the sensor substrate front surface 65a. The sensor substrate 65 has a through hole penetrating the sensor substrate 65 in the width direction X, and the sensor recess 61 is formed by the through hole. It should be noted that the sensor substrate 65 may be formed with a recess that forms the sensor recess 61 instead of the through hole. In this case, the bottom surface of the sensor recess 61 is not formed by the membrane portion 62, but is formed by the bottom surface of the recess of the sensor substrate 65.

The sensor film portion 66 is superposed on the sensor substrate surface 65a of the sensor substrate 65 and extends in a film shape along the sensor substrate surface 65a. In the flow rate sensor 22, the sensor surface 22 a is formed by the sensor film portion 66, and the sensor back surface 22 b is formed by the sensor substrate 65. In this case, the sensor back surface 22b is the sensor board back surface 65b of the sensor board 65.

The sensor film portion 66 has a plurality of layers such as an insulating layer, a conductive layer, and a protective layer, and has a multilayer structure. Each of these is formed in a film shape and extends along the sensor substrate surface 65a. The sensor film portion 66 has a wiring pattern such as wiring and resistors, and this wiring pattern is formed by a conductive layer.

In the flow rate sensor 22, the sensor recess 61 is formed by processing a part of the sensor substrate 65 by wet etching. In the manufacturing process of the flow rate sensor 22, a mask such as a silicon nitride film is attached to the sensor substrate back surface 65b of the sensor substrate 65 and is anisotropically applied to the sensor substrate back surface 65b using an etching solution until the sensor film portion 66 is exposed. Etching. The sensor recess 61 may be formed by performing dry etching on the sensor substrate 65.

The sensor SA50 has a flow rate detection circuit that detects the flow rate of air, and at least a part of this flow rate detection circuit is included in the flow rate sensor 22. As shown in FIG. 13, the sensor SA50 includes a heating resistor 71, temperature measuring resistors 72 and 73, and an indirectly heated resistor 74 as circuit elements included in the flow rate detection circuit. These resistors 71 to 74 are included in the flow rate sensor 22 and are formed by the conductive layer of the sensor film portion 66. In this case, the sensor film portion 66 has resistors 71 to 74, and these resistors 71 to 74 are included in the wiring pattern of the conductive layer. The resistors 71 to 74 correspond to detection elements. In addition, in FIG. 13, the wiring pattern including the resistors 71 to 74 is illustrated by dot hatching. The flow rate detection circuit can also be referred to as a flow rate measurement unit that measures the flow rate of air.

The heating resistor 71 is a resistance element that generates heat as the heating resistor 71 is energized. The heating resistor 71 heats the sensor film portion 66 by generating heat, and corresponds to a heater portion. The resistance temperature detectors 72 and 73 are resistance elements for detecting the temperature of the sensor film portion 66, and correspond to the temperature detection portion. The resistance values of the resistance temperature detectors 72 and 73 change according to the temperature of the sensor film portion 66. In the flow rate detection circuit, the temperature of the sensor film portion 66 is detected using the resistance values of the resistance temperature detectors 72 and 73. The flow rate detection circuit raises the temperatures of the sensor film portion 66 and the temperature measuring resistors 72 and 73 by the heat generating resistor 71, and when air flows in the measurement flow path 32, the temperature measuring resistors 72 and 73. The air flow rate and the flow direction are detected using the change mode of the detected temperature according to.

The heat-generating resistor 71 is arranged substantially at the center of the membrane portion 62 in each of the height direction Y and the depth direction Z. The heating resistor 71 is formed in a rectangular shape extending in the height direction Y as a whole. The center line CL1 of the heating resistor 71 passes through the center CO1 of the heating resistor 71 and extends linearly in the height direction Y. The center line CL1 passes through the center of the membrane portion 62. The heating resistor 71 is arranged at a position spaced inward from the peripheral portion of the membrane portion 62. In the heating resistor 71, the distance from the center CO1 is the same at the end on the mold front end side and the end on the mold base end side.

Each of the resistance temperature detectors 72 and 73 is formed in a rectangular shape extending in the height direction Y as a whole, and is arranged in the depth direction Z. A heating resistor 71 is provided between the temperature measuring resistors 72 and 73. Of the temperature measuring resistors 72 and 73, the upstream temperature measuring resistor 72 is provided at a position separated from the heat generating resistor 71 on the upstream side of the mold. The downstream resistance temperature detector 73 is provided at a position separated from the heating resistor 71 on the downstream side of the mold. The center line CL2 of the upstream resistance temperature detector 72 and the center line CL3 of the downstream resistance temperature detector 73 both linearly extend in parallel to the center line CL1 of the heating resistor 71. The heating resistor 71 is provided at an intermediate position between the upstream temperature measuring resistor 72 and the downstream temperature measuring resistor 73 in the depth direction Z.

Regarding the sensor SA50 of the present embodiment, in FIG. 10, the mold upstream surface 55c side is referred to as the mold upstream side, and the mold downstream surface 55d side is referred to as the mold downstream side. The mold front end surface 55a side is referred to as the mold front end side, and the mold base end surface 55b side is referred to as the mold base end side.

Returning to the explanation of FIG. 13, the indirectly heated resistor 74 is a resistance element for detecting the temperature of the heating resistor 71. The indirectly heated resistor 74 extends along the peripheral edge of the heat generating resistor 71. The resistance value of the indirectly heated resistor 74 changes according to the temperature of the heating resistor 71. In the flow rate detection circuit, the resistance value of the indirectly heated resistor 74 is used to detect the temperature of the heating resistor 71.

The sensor SA50 has a heating wire 75 and temperature measuring wires 76 and 77. These wirings 75 to 77 are included in the wiring pattern of the sensor film portion 66, like the resistors 71 to 74. The heat generating wiring 75 extends in the height direction Y from the heat generating resistor 71 toward the mold base end side. The upstream temperature measuring wiring 76 extends in the height direction Y from the upstream temperature measuring resistor 72 toward the mold front end side. The downstream temperature measuring wiring 77 extends in the height direction Y from the downstream temperature measuring resistor 73 toward the mold front end side.

As shown in FIGS. 14 and 15, the center line CL4 of the measurement flow passage 32 passes through the center CO2 of the measurement inlet 35 and the center CO3 of the measurement outlet 36 and extends linearly along the measurement flow passage 32. .. The sensor SA50 is provided in the measurement flow path 32 between the measurement inlet 35 and the measurement outlet 36. The sensor SA50 is provided at a position separated from the measurement inlet 35 to the upstream side and a position separated from the measurement outlet 36 to the upstream side. Note that in FIG. 14, the center line of the region of the measurement flow path 32 excluding the internal space of the SA insertion hole 107 is shown as the center line CL4.

In the passage channel 31, the opening area of the passage outlet 34 is smaller than the opening area of the passage inlet 33. The height dimension of the passage outlet 34 and the height dimension of the passage inlet 33 are the same in the height direction Y, while the width dimension of the passage outlet 34 is smaller than the width dimension of the passage inlet 33 in the width direction X. There is. The opening area of the passage inlet 33 is the area of the region including the center CO21 of the passage inlet 33, and the opening area of the passage outlet 34 is the area of the region including the center CO24 of the passage outlet 34.

In the measurement flow path 32, the total value of the opening areas of the plurality of measurement outlets 36 is smaller than the opening area of the measurement inlet 35. This may be simply referred to as the opening area of the measurement outlet 36 being smaller than the opening area of the measurement inlet 35. The opening area of the measurement inlet 35 is the area of the region including the center CO2 of the measurement inlet 35, and the opening area of the measurement outlet 36 is the area of the region including the center CO3 of the measurement outlet 36.

As shown in FIGS. 15 and 16, the housing 21 has a measurement floor surface 101, a measurement ceiling surface 102, a front measurement wall surface 103, and a back measurement wall surface 104 as forming surfaces forming the measurement flow path 32. The measurement floor surface 101, the measurement ceiling surface 102, the front measurement wall surface 103, and the back measurement wall surface 104 all extend along the center line CL4 of the measurement flow path 32. The measurement floor surface 101, the measurement ceiling surface 102, the front measurement wall surface 103, and the back measurement wall surface 104 form a portion of the measurement flow path 32 extending in the depth direction Z. The measurement floor surface 101 corresponds to the floor surface, the front measurement wall surface 103 corresponds to the front wall surface 103, and the back measurement wall surface 104 corresponds to the back wall surface. The width direction X corresponds to the front-back direction in which the front wall surface and the back wall surface are lined up.

The measurement floor surface 101 and the measurement ceiling surface 102 are provided between the front measurement wall surface 103 and the back measurement wall surface 104. The measurement floor surface 101 faces the mold front end surface 55a of the sensor SA50 and extends straight in the depth direction Z. The measurement ceiling surface 102 is provided on the opposite side of the measurement floor surface 101 with the center line CL4 in the height direction Y. An SA insertion hole 107 into which the sensor SA50 is inserted is provided in a portion of the housing 21 that forms the measurement ceiling surface 102. The SA insertion hole 107 is closed by the sensor SA50. The measurement flow path 32 also includes a gap between the sensor SA50 and the housing 21 in the internal space of the SA insertion hole 107.

The front measurement wall surface 103 and the back measurement wall surface 104 are a pair of wall surfaces facing each other via the measurement floor surface 101 and the measurement ceiling surface 102. The front measurement wall surface 103 faces the mold surface 55e of the sensor SA50, and extends from the end of the measurement floor surface 101 on the airflow front side toward the housing base end side. Particularly, the front measurement wall surface 103 faces the flow rate sensor 22 of the sensor SA50. The back measurement wall surface 104 faces the mold back surface 55f of the sensor SA50 and extends from the end of the measurement floor surface 101 on the back side of the airflow toward the housing base end side. Note that, in FIGS. 15 and 16, the internal structure of the sensor SA50 is simplified and only the mold portion 55 and the flow rate sensor 22 are shown.

The housing 21 has a front narrowing portion 111 and a back narrowing portion 112. These narrowed portions 111 and 112 gradually narrow the measurement flow passage 32 so that the cross-sectional area S4 of the measurement flow passage 32 gradually decreases from the upstream of the measurement inlet 35 or the like toward the flow rate sensor 22. Further, the narrowed portions 111 and 112 gradually narrow the measurement flow passage 32 so that the cross-sectional area S4 gradually decreases from the downstream of the flow rate sensor 22 such as the measurement outlet 36 toward the flow rate sensor 22. Regarding the measurement flow channel 32, the area of the region orthogonal to the center line CL4 is referred to as the cross-sectional area S4, and this cross-sectional area S4 can also be referred to as the flow channel area.

The front narrowing portion 111 is a convex portion in which a part of the front measurement wall surface 103 projects toward the back measurement wall surface 104. The back narrowing portion 112 is a convex portion in which a part of the back measurement wall surface 104 projects toward the front measurement wall surface 103. The front narrowing portion 111 and the back narrowing portion 112 are arranged in the height direction Y and face each other in the height direction Y. These diaphragms 111 and 112 are bridged over the measurement ceiling surface 102 and the measurement floor surface 101. The narrowed portions 111 and 112 gradually reduce the measurement width dimension W1 that is the distance between the front measurement wall surface 103 and the back measurement wall surface 104 in the width direction X from the upstream side toward the flow rate sensor 22. Further, the narrowed portions 111 and 112 gradually reduce the measurement width dimension W1 from the downstream side toward the flow rate sensor 22.

The throttles 111 and 112 gradually approach the center line CL4 from the upstream side toward the flow rate sensor 22 in the measurement flow path 32. In the measurement flow path 32, the separation distances W2 and W3 between the narrowed portions 111 and 112 and the center line CL4 in the width direction X gradually decrease from the upstream to the flow sensor 22. Further, the throttle portions 111 and 112 gradually approach the center line CL4 from the downstream side toward the flow rate sensor 22 in the measurement flow path 32. In the measurement flow path 32, the distances W2 and W3 between the narrowed portions 111 and 112 and the center line CL4 in the width direction X gradually decrease from the downstream side toward the flow rate sensor 22.

In the narrowed portions 111 and 112, the portions closest to the center line CL4 are the top portions 111a and 112a. In this case, in the narrowed portions 111 and 112, the distances W2 and W3 from the center line CL4 are the smallest in the top portions 111a and 112a. Of the tops 111a and 112a, the front top 111a is the top of the front narrowed portion 111, and the back top 112a is the top of the back narrowed portion 112. The front top part 111a and the back top part 112a are arranged in the width direction X and face each other.

The flow rate sensor 22 is provided between the front throttle portion 111 and the back throttle portion 112. Specifically, the center CO1 of the heating resistor 71 of the flow sensor 22 is provided between the front top portion 111a and the back top portion 112a. Regarding the heating resistor 71, when a straight virtual line that passes through the center CO1 and is orthogonal to the center line CL1 and extends in the width direction X is referred to as a center line CL5, both the front top portion 111a and the back top portion 112a are the center line CL5. It is placed on top. In this case, the center CO1 of the heating resistor 71 and the top portion 111a are aligned in the width direction X, and the center CO1 of the heating resistor 71 and the top portion 111a face each other in the width direction X.

As shown in FIG. 16, the sensor support portion 51 of the sensor SA50 is provided at a position closer to the front diaphragm portion 111 than the back diaphragm portion 112 in the width direction X. That is, the sensor support portion 51 is provided at a position closer to the front measurement wall surface 103 than the back measurement wall surface 104. On the center line CL5 of the heating resistor 71, the front distance L1 which is the separation distance between the flow sensor 22 in the width direction X and the front measurement wall surface 103 is the flow sensor 22 in the width direction X and the back measurement wall surface 104. Is smaller than the back distance L2 which is the separation distance. That is, the relationship of L1<L2 is established. The front distance L1 is the distance between the center CO1 of the heating resistor 71 and the front top 111a of the front narrowed portion 111. The back distance L2 is a distance between the back surface 55f of the mold and the back top 112a of the back throttle 112 on the center line CL5 of the heating resistor 71.

The mold tip surface 55a of the sensor support portion 51 is arranged at a position closer to the measurement floor surface 101 than the measurement ceiling surface 102 in the height direction Y. In this case, in the measurement flow path 32, the floor distance L3 is smaller than the front distance L1. That is, the relationship of L1>L3 is established. The floor distance L3 is the distance between the mold tip surface 55a and the measurement floor surface 101 in the height direction Y. Specifically, it is the separation distance between the portion of the measurement floor surface 101 facing the mold front end surface 55a and the portion closest to the mold front end surface 55a and the mold front end surface 55a.

In the measurement flow path 32, of the area surrounded by the inner surface of the housing 21 and the outer surface of the sensor SA50, a planar area orthogonal to the center line CL4 and passing through the center CO1 of the heating resistor 71 is referred to as a sensor area 121. .. The air flowing from the measurement inlet 35 to the measurement outlet 36 in the measurement flow channel 32 needs to pass through the sensor region 121.

The sensor area 121 has a front area 122 and a back area 123. The front area 122 is an area closer to the front measurement wall surface 103 than the mold surface 55e in the width direction X. The back area 123 is an area closer to the back measurement wall surface 104 than the mold back surface 55f in the width direction X. These regions 122 and 123 extend in the height direction Y from the measurement floor surface 101 toward the measurement ceiling surface 102 side. In the measurement flow channel 32, the sensor SA50 is arranged between the front area 122 and the back area 123 in the width direction X.

The front area 122 has a floor side area 122a and a ceiling side area 122b. The floor-side area 122a is an area extending from the floor-side end of the flow rate sensor 22 toward the measurement floor surface 101 in the front area 122. In the floor side region 122a, the end portion on the front end side of the housing is formed by the measurement floor surface 101. Therefore, the floor area 122a is an area between the flow rate sensor 22 and the measurement floor surface 101 in the height direction Y. The ceiling side region 122b is a region that extends from the ceiling side end of the flow rate sensor 22 toward the measurement ceiling surface 102 in the front region 122. In the front region 122, the end portion on the base end side of the housing is formed by a ceiling side boundary portion which is a boundary portion between the inner surface of the housing 21 and the outer surface of the sensor SA50. Therefore, the ceiling side region 122b is a region between the flow rate sensor 22 and the ceiling side boundary portion in the height direction Y.

When the area of the sensor area 121 is referred to as an area area S1, the area area S1 is a cross-sectional area of a portion of the measurement flow channel 32 where the flow rate sensor 22 is provided. The area area S1 includes a floor area S2, which is the area of the floor area 122a, and a ceiling area S3, which is the area of the ceiling area 122b. In the front area 122, the ceiling side area S3 is smaller than the floor side area S2. That is, the relationship of S3<S2 is established.

According to this embodiment described so far, the front distance L1 is larger than the floor distance L3 in the measurement flow path 32. In this configuration, the amount of air flowing along the front measurement wall surface 103 or the mold surface 55e tends to be larger than the amount of air flowing along the measurement floor surface 101 or the mold front end surface 55a. In this case, since air easily flows along the flow rate sensor 22 on the mold surface 55e, it is unlikely that the amount of air flowing along the flow rate sensor 22 becomes insufficient and the flow rate detection accuracy of the flow rate sensor 22 decreases. Has become. Therefore, the flow rate detection accuracy of the flow rate sensor 22 can be increased, and as a result, the air flow rate measurement accuracy of the air flow meter 20 can be increased.

In a configuration in which the floor distance L3 is smaller than the front distance L1, there is a concern that the measurement flow channel 32 is narrowed from the measurement floor surface 101 side and the area S1 of the sensor area 121 becomes insufficient. In the measurement flow channel 32, when the cross-sectional area such as the area S1 is insufficient, pressure loss increases, and it becomes difficult for air to flow from the passage flow channel 31 into the measurement flow channel 32. In this case, the air flow rate in the measurement flow path 32 becomes insufficient, and the air flow is easily separated or disturbed in the measurement flow path 32, and the separation result or the disturbance easily causes noise to be included in the detection result of the flow rate sensor 22. I will end up.

On the other hand, according to the present embodiment, the front distance L1 is smaller than the back distance L2 in the measurement flow path 32. In this case, even if the area between the mold tip surface 55a of the sensor SA50 and the measurement floor surface 101 is narrow, the back area 123 between the mold back surface 55f and the back measurement wall surface 104 is relatively wide. In this configuration, the back area 123 suppresses the shortage of the area S1 of the sensor area 121, and the shortage of the air flow rate in the measurement flow path 32 is less likely to occur. In this case, separation or turbulence of the airflow is less likely to occur in the measurement flow path 32, and it is possible to suppress the detection result of the flow rate sensor 22 from including noise. Further, in this case, since the pressure loss in the measurement flow channel 32 is reduced and the flow rate is easily increased, the range of flow rate detection by the flow rate sensor 22 can be expanded. That is, fluctuations in the output of the air flow meter 20 are suppressed, and the air flow meter 20 can have a dynamic range. Therefore, the air flow meter 20 can realize both the output fluctuation suppression and the dynamic range.

The front distance L1 is smaller than the back distance L2. With this configuration, when the air flow meter 20 is manufactured, even if the relative position of the sensor SA50 with respect to the housing 21 deviates in the width direction X due to an attachment error of the sensor SA50 with respect to the housing 21, the front distance L1 is smaller than the back distance L2. Easy to maintain. Thus, even if an error in mounting the sensor SA50 on the housing 21 occurs, a configuration in which the detection accuracy of the flow rate sensor 22 is unlikely to be reduced can be realized by the relationship between the front distance L1 and the back distance L2.

According to this embodiment, the housing 21 has the front throttle portion 111. In this configuration, since the front throttle portion 111 gradually narrows the measurement flow passage 32 from the measurement inlet 35 side toward the flow rate sensor 22, even if separation or turbulence occurs in the air flow, the front throttle portion 111 causes The separation and turbulence are reduced by rectifying the flow of air. In this case, peeling or turbulence hardly reaches the flow rate sensor 22, so that the detection accuracy of the flow rate sensor 22 can be improved. Moreover, since the front distance L1 is the distance between the front throttle portion 111 and the flow rate sensor 22, the air flowing along the flow rate sensor 22 can be reliably rectified by the front throttle portion 111.

According to this embodiment, the front distance L1 is the distance between the front top 111a of the front throttle 111 and the flow sensor 22. In the front throttle portion 111, the portion having the highest rectification effect is likely to be the front top portion 111a. Therefore, by causing the portion having the highest rectification effect to face the flow rate sensor 22, the air flowing along the flow rate sensor 22 is separated or disturbed. It is possible to reliably suppress the inclusion of. Thereby, the detection accuracy of the flow rate sensor 22 can be further improved.

According to this embodiment, the housing 21 has the back drawn portion 112. With this configuration, the back throttle 112 gradually narrows the measurement flow passage 32 from the measurement inlet 35 side toward the flow rate sensor 22, so that even if separation or turbulence occurs in the flow of air, the back throttle 112 causes air to flow. The flow is rectified to reduce these separations and disturbances. In the measurement flow channel 32, it is considered that the air flowing toward the flow rate sensor 22 at a height position near the flow rate sensor 22 in the height direction Y easily passes through both the front side and the back side of the sensor support portion 51. Therefore, rectifying the air flowing along the back measurement wall surface 104 by the back narrowing portion 112 is also effective in suppressing peeling and turbulence from reaching the flow rate sensor 22.

According to this embodiment, in the measurement flow path 32, the ceiling side area S3 of the ceiling side area 122b is smaller than the floor side area S2 of the floor side area 122a. With this configuration, the pressure loss in the ceiling side region 122b is more likely to increase than in the floor side region 122a, and it is difficult for air to flow. Therefore, even if the measurement flow path 32 has a configuration in which the air flowing along the measurement ceiling surface 102 tends to become faster or more than the air flowing along the measurement floor surface 101, the ceiling side region 122b. It is possible to equalize the speed and amount of air flowing between the floor area 122a and the floor area 122a. As a result, it is possible to prevent the detection accuracy of the flow rate sensor 22 from being deteriorated due to the mixture of the fast air flow and the slow air flow in the air flow reaching the sensor region 121.

According to this embodiment, the measurement flow path 32 is curved so that the measurement ceiling surface 102 is on the outer peripheral side and the measurement floor surface 101 is on the inner peripheral side. In this configuration, the air flowing along the measurement ceiling surface 102 tends to be faster or more than the air flowing along the measurement floor surface 101 due to centrifugal force or the like. Therefore, it is effective that the ceiling-side area S3 is smaller than the floor-side area S2 in order to equalize the speed and amount of the air flowing in the ceiling-side area 122b and the floor-side area 122a.

According to the present embodiment, the front distance L1 is the distance between the front measurement wall surface 103 and the heating resistor 71. In the flow rate sensor 22, since the flow rate is detected for the air flowing along the heating resistor 71, the detection accuracy of the flow rate sensor 22 is controlled by managing the positional relationship between the heating resistor 71 and the front measurement wall surface 103. Can be increased.

According to the present embodiment, in the sensor SA50, the mold front surface 55e and the mold back surface 55f are both formed by the resin mold portion 55. With this configuration, since the smoothness of the mold front surface 55e and the mold back surface 55f can be easily managed, the air flowing along the mold front surface 55e and the mold back surface 55f is less likely to be separated or disturbed.

<Explanation of Group B>
As shown in FIGS. 8 and 17, the housing 21 has an SA accommodation area 150. The SA accommodation area 150 is provided closer to the housing base end side than the bypass flow passage 30 and accommodates a part of the sensor SA50. At least the mold base end surface 55b of the sensor SA50 is housed in the SA housing area 150. The measurement flow path 32 and the SA accommodation area 150 are arranged in the height direction Y. The sensor SA50 is arranged at a position straddling the boundary portion between the measurement flow channel 32 and the SA accommodation area 150 in the height direction Y. At least the mold tip surface 55a of the sensor SA50 and the flow rate sensor 22 are housed in the measurement flow channel 32. The SA accommodation area 150 corresponds to the accommodation area. In addition, in FIGS. 17 and 18, the internal structure of the sensor SA50 is simplified and only the mold portion 55 and the flow rate sensor 22 are shown.

The housing 21 has a first housing part 151 and a second housing part 152. The housing portions 151 and 152 are assembled and integrated with each other, and the housing 21 is formed in this state. The first housing portion 151 forms the SA accommodation area 150. The first housing portion 151 forms the bypass flow passage 30 in addition to the SA accommodation area 150. The inner surface of the first housing portion 151 forms the SA accommodation area 150 and the bypass flow passage 30 as the inner surface of the housing 21. A housing opening 151a (see FIG. 19) is provided at the open end of the first housing portion 151. The housing opening 151a opens the SA accommodation area 150 toward the side opposite to the measurement flow path 32.

In the state where the sensor SA50 is housed in the SA housing area 150 and the measurement flow channel 32, a gap is formed between the outer surface of the sensor SA50 and the inner surface of the first housing portion 151. The second housing portion 152 fills this gap. Specifically, the second housing portion 152 is in a state of being inserted between the outer surface of the sensor SA50 and the inner surface of the first housing portion 151 in the SA accommodation area 150.

As shown in FIG. 17, the housing 21 has a housing partition 131. The housing partition portion 131 is a convex portion provided on the inner surface of the first housing portion 151, and projects from the first housing portion 151 toward the sensor SA50. In this case, the first housing portion 151 has the housing partition 131. The tip of the housing partition 131 is in contact with the outer surface of the sensor SA50. The housing partition section 131 partitions the SA housing area 150 and the measurement flow path 32 between the outer surface of the sensor SA50 and the inner surface of the first housing section 151.

The inner surface of the first housing portion 151 has a housing flow path surface 135, a housing accommodation surface 136, and a housing step surface 137. The housing flow path surface 135, the housing receiving surface 136, and the housing step surface 137 extend in a direction intersecting the height direction Y, and make a circle around the sensor SA50. In the sensor SA50, the center line CL1 of the heating resistor 71 extends in the height direction Y, and the housing flow path surface 135, the housing housing surface 136, and the housing step surface 137 are circumferentially arranged around the center line CL1. It is extended.

In the first housing portion 151, a housing step surface 137 is provided between the housing front end surface 21a and the housing base end surface 21b. The housing step surface 137 faces the housing base end side in the height direction Y. The housing step surface 137 is inclined with respect to the center line CL1 and faces the inner side in the radial direction on the center line CL1 side. The housing step surface 137 intersects in the height direction Y and corresponds to the housing intersecting surface. On the inner surface of the first housing part 151, the corners of the housing flow path surface 135 and the housing step surface 137 and the corners of the housing accommodation surface 136 and the housing step surface 137 are chamfered. The height direction Y corresponds to the arrangement direction in which the measurement flow path and the accommodation area are arranged side by side.

The housing flow path surface 135 forms the measurement flow path 32, and extends from the inner peripheral end of the housing step surface 137 toward the housing front end side. The housing flow path surface 135 extends from the housing step surface 137 toward the side opposite to the SA accommodation area 150. On the other hand, the housing housing surface 136 forms the SA housing area 150, and extends from the outer peripheral end of the housing step surface 137 toward the housing base end side. The housing accommodation surface 136 extends from the housing step surface 137 toward the side opposite to the measurement flow path 32. The housing step surface 137 is provided between the housing flow path surface 135 and the housing housing surface 136, and forms a step on the inner surface of the first housing portion 151. The housing step surface 137 connects the housing flow path surface 135 and the housing housing surface 136.

The outer surface of the sensor SA50 is formed by the outer surface of the mold portion 55. The outer surface of the sensor SA50 has an SA flow path surface 145, an SA housing surface 146, and an SA step surface 147. The SA flow path surface 145, the SA housing surface 146, and the SA step surface 147 extend in a direction intersecting with the height direction Y, and are a portion that makes a circle around the outer surface of the sensor SA50. The SA flow path surface 145, the SA housing surface 146, and the SA step surface 147 extend in the circumferential direction around the center line CL1 of the heating resistor 71.

In the sensor SA50, an SA step surface 147 is provided between the mold front end surface 55a and the mold base end surface 55b. The SA step surface 147 faces the mold front end surface 55a side in the height direction Y. The SA step surface 147 is inclined with respect to the center line CL1 and faces the outer side in the radial direction opposite to the center line CL1. The SA step surface 147 intersects in the height direction Y and corresponds to a unit intersection surface. Further, the SA channel surface 145 corresponds to the unit channel surface, and the SA accommodation surface 146 corresponds to the unit accommodation surface. On the outer surface of the sensor SA50, the corners of the SA flow path surface 145 and the SA step surface 147 and the corners of the SA housing surface 146 and the SA step surface 147 are chamfered.

The SA flow path surface 145 forms the measurement flow path 32, and extends in the height direction Y from the inner peripheral end of the SA step surface 147 toward the mold front end side. The SA flow path surface 145 extends from the SA step surface 147 toward the side opposite to the SA accommodation area 150. On the other hand, the SA housing surface 146 forms the SA housing area 150, and extends from the outer peripheral end of the SA step surface 147 toward the mold base end side. The SA accommodation surface 146 extends from the SA step surface 147 toward the side opposite to the measurement flow channel 32. The SA step surface 147 is provided between the SA flow path surface 145 and the SA housing surface 146, and forms a step on the outer surface of the sensor SA50. The SA step surface 147 connects the SA flow path surface 145 and the SA housing surface 146.

In the sensor SA50, each of the SA flow path surface 145, the SA housing surface 146, and the SA step surface 147 is formed by the mold upstream surface 55c, the mold downstream surface 55d, the mold surface 55e, and the mold back surface 55f.

In the air flow meter 20, the housing step surface 137 facing the housing base end side and the SA step surface 147 facing the housing front end side face each other. Further, the housing flow path surface 135 facing the inner peripheral side and the SA flow path surface 145 facing the outer peripheral side face each other. Similarly, the housing accommodation surface 136 facing the inner peripheral side and the SA accommodation surface 146 facing the outer peripheral side face each other.

The housing partition 131 is provided on the housing step surface 137 and extends in the height direction Y toward the housing base end side. The center line CL11 of the housing partition 131 extends linearly in the height direction Y. The housing partition 131, together with the housing step surface 137, surrounds the sensor SA50 in an annular shape. In this case, as shown in FIG. 19, the housing partition portion 131 has a portion extending in the width direction X and a portion extending in the depth direction Z, and has a substantially rectangular frame shape as a whole.

Returning to the description of FIG. 17, the tip of the housing partition 131 contacts the SA step surface 147 of the sensor SA50. The housing partition 131 and the SA step surface 147 are in close contact with each other to enhance the sealing property of the part that partitions the SA accommodation area 150 and the measurement flow path 32. The SA step surface 147 is a flat surface that extends straight in the direction intersecting the height direction Y. In this embodiment, the housing step surface 137 and the SA step surface 147 do not extend in parallel, and the SA step surface 147 is inclined with respect to the housing step surface 137. As described above, even if the SA step surface 147 and the housing step surface 137 are not parallel to each other, the housing partition portion 131 is in contact with the SA step surface 147, so that the outer surface of the sensor SA50 and the first housing portion 151 are in contact with each other. The sealability is improved at the portion where it contacts the inner surface. The housing step surface 137 and the SA step surface 147 may extend in parallel.

The housing partition 131 is orthogonal to the housing step surface 137. In this case, the center line CL11 of the housing partition 131 and the housing step surface 137 are orthogonal to each other. The housing partition 131 has a tapered shape. The directions X and Z orthogonal to the height direction Y are the width directions for the housing partition 131, and the width dimension of the housing partition 131 in the width direction gradually decreases toward the tip of the housing partition 131. ing. Each of the pair of side surfaces of the housing partition portion 131 extends straight from the housing step surface 137. In this case, the housing partition 131 has a tapered cross section.

The housing partition portion 131 is disposed on the housing step surface 137 at a position closer to the housing flow path surface 135 than the housing accommodation surface 136. In this case, in the directions X and Z orthogonal to the height direction Y, the distance between the housing partition 131 and the housing housing surface 136 is smaller than the distance between the housing partition 131 and the housing flow path surface 135. ..

A portion of the housing step surface 137 closer to the housing flow channel surface 135 than the housing partition 131 forms the measurement flow channel 32 together with the housing flow channel surface 135. A portion on the housing accommodation surface 136 side of the housing partition 131 forms the SA accommodation area 150 together with the housing accommodation surface 136.

A portion of the SA step surface 147 closer to the SA flow channel surface 145 than the housing partition 131 forms the measurement flow channel 32 together with the SA flow channel surface 145. A portion on the SA accommodation surface 146 side of the housing partition 131 forms an SA accommodation area 150 together with the SA accommodation surface 146.

Next, a method of manufacturing the air flow meter 20 will be described with reference to FIGS. 18 to 21, focusing on the procedure of mounting the sensor SA50 in the housing 21.

The manufacturing process of the air flow meter 20 includes a process of manufacturing the sensor SA50 and a process of manufacturing the first housing portion 151 by resin molding or the like. After these steps, the step of assembling the sensor SA50 with the first housing portion 151 is performed.

In the process of manufacturing the sensor SA50, the molding part 55 of the sensor SA50 is manufactured by resin molding or the like using an injection molding machine or an injection molding device having a mold device. In this step, a molten resin obtained by melting a resin material is injected from an injection molding machine and press-fitted into the mold device. Further, in this step, an epoxy thermosetting resin such as an epoxy resin is used as the resin material forming the mold portion 55.

In the step of manufacturing the first housing portion 151, the first housing portion 151 is manufactured by resin molding or the like using an injection molding device or the like. In this step, a thermoplastic resin such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS) is used as the resin material forming the first housing portion 151. As described above, the first housing portion 151 formed of the thermoplastic resin is softer than the mold portion 55 formed of the thermosetting resin. In other words, the first housing portion 151 has lower hardness and higher flexibility than the mold portion 55.

In the step of assembling the sensor SA50 to the first housing part 151, the sensor SA50 is inserted into the first housing part 151 from the housing opening 151a as shown in FIG. Here, as shown in FIG. 20, after the SA step surface 147 comes into contact with the tip of the housing partition 131, the sensor SA50 is further pushed toward the tip of the housing into the first housing 151. In this case, due to the hardness of the first housing portion 151 being lower than the hardness of the mold portion 55, as shown in FIG. 21, the housing partition portion 131 has its tip portion crushed by the SA step surface 147. To be transformed. In the housing partition 131, the newly formed tip surface is easily brought into close contact with the SA step surface 147 by crushing the tip portion, and the sealing performance between the housing partition 131 and the SA step surface 147 is improved. Note that, in FIG. 17, a portion of the housing partition portion 131 crushed by the sensor SA50 is shown by a two-dot chain line as a virtual line.

In the assembly process of the sensor SA50, when the tip of the housing partition 131 is crushed by the SA step surface 147, fragments of the housing partition 131 are generated as crushed scraps, and the crushed scraps are generated in the measurement flow path 32. There is concern that it will enter. When the crushed dust that has entered the measurement flow path 32 comes into contact with or adheres to the flow rate sensor 22 as foreign matter in the measurement flow path 32, it is assumed that the detection accuracy of the flow rate sensor 22 is reduced.

On the other hand, in the present embodiment, the crushed waste is difficult to enter the measurement flow path 32. Specifically, as shown in FIG. 20, among the angles between the center line CL11 of the housing partition 131 and the SA step surface 147, the accommodation side angle θ12 facing the SA accommodation area 150 is the measurement flow path 32. Is larger than the flow channel side angle θ11 facing toward. That is, the relationship of θ12>θ11 is established. In this configuration, the tip of the housing partition 131 is more likely to fall or collapse toward the SA accommodation area 150 side than the measurement flow channel 32 side. Therefore, even if a crushed residue is generated, it is difficult for the crushed residue to enter the measurement flow path 32.

The flow path side angle θ11 is an angle of a portion of the outer surface of the housing partition 131 closest to the SA step surface 147, and the accommodation side angle θ12 is an angle opposite to the flow path side angle θ11 with the center line CL11 interposed therebetween. is there.

After the sensor SA50 is assembled to the first housing part 151, a step of manufacturing the second housing part 152 by resin molding or the like using an injection molding device or the like is performed. In this step, the mold device is mounted on the first housing portion 151 together with the sensor SA50, and the molten resin obtained by melting the resin material is injected from the injection molding machine and press-fitted inside the mold device. In this way, by injecting the molten resin into the mold device, the molten resin is filled in the gap between the first housing portion 151 and the sensor SA50. In this case, since the housing partition 131 is in close contact with the outer surface of the sensor SA50 as described above, it is restricted that the molten resin enters the measurement channel 32 through the gap between the first housing 151 and the sensor SA50. .. Then, the second housing portion 152 is formed by solidifying the molten resin inside the mold device.

As the resin material forming the second housing portion 152, a thermoplastic resin such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS) is used as in the first housing portion 151. Both of the first housing portion 151 and the second housing portion 152 contain a carbon material having conductivity. Examples of the carbon material include carbon powder, carbon fiber, nanocarbon, graphene, and carbon microparticles.

The first housing portion 151 is easier to discharge when charged than the second housing portion 152. For example, the first housing portion 151 has a larger carbon material content rate and content than the second housing portion 152. When a portion of the housing 21 that easily becomes a path for electric charges during discharge is referred to as a conductive portion, the conductive portion is larger in the first housing portion 151 than in the second housing portion 152. The conductive portion contains a plurality of carbon powders, carbon fibers, nanocarbons, graphenes, and carbon microparticles, and examples of the nanocarbons include carbon nanotubes, carbon nanofibers, and fullerenes.

According to the present embodiment described thus far, the housing partition 131 protruding from the inner surface of the housing 21 partitions the measurement flow channel 32 and the SA accommodation area 150 between the sensor SA50 and the housing 21. In this configuration, since the tip portion of the housing partition 131 and the sensor SA50 are easily brought into close contact with each other, a gap is unlikely to be formed between the inner surface of the housing 21 and the outer surface of the sensor SA50. Therefore, when the molten resin is injected into the SA housing area 150 of the first housing portion 151 to form the second housing portion 152, the molten resin passes through the gap between the first housing portion 151 and the sensor SA50 and the measurement flow path 32 It is regulated to enter.

In this case, the molten resin that has entered the measurement channel 32 through the gap between the first housing 151 and the sensor SA50 is solidified, and the solidified portion causes the shape of the measurement channel 32 to change unintentionally. It's getting harder. Further, it is less likely that the solidified portion will peel off from the first housing portion 151 and the sensor SA50 in the measurement flow path 32 and come into contact with or adhere to the flow rate sensor 22 as a foreign matter. Therefore, it is possible to prevent the detection accuracy of the flow rate sensor 22 from being lowered by the molten resin that has entered the measurement flow path 32 from the SA accommodation area 150. As a result, the accuracy of the air flow rate detected by the flow rate sensor 22 can be increased, and as a result, the accuracy of the air flow rate measured by the air flow meter 20 can be increased.

According to the present embodiment, the housing partition 131 circulates around the sensor SA50 in an annular shape. With this configuration, the housing partition 131 can create a state in which the outer surface of the sensor SA50 and the inner surface of the first housing portion 151 are in close contact with each other on the entire outer surface of the sensor SA50. Therefore, the housing partitioning portion 131 can enhance the sealing property in the entire boundary portion between the measurement flow channel 32 and the SA accommodation area 150.

According to the present embodiment, the housing partition 131 is provided at a position closer to the housing flow path surface 135 than the housing accommodation surface 136 on the housing step surface 137. In this structure, the measurement flow path 32 and the SA accommodation area 150 are partitioned by the housing partition 131 at a position as close to the measurement flow path 32 as possible, so that the measurement flow in the gap between the first housing section 151 and the sensor SA50 is separated. The portion included in the path 32 can be made as small as possible. Here, in the measurement flow path 32, the gap between the first housing portion 151 and the sensor SA50 is a region in which the air flowing from the measurement inlet 35 toward the measurement outlet 36 is likely to cause turbulence in the air flow. It has become. For this reason, as the gap between the first housing portion 151 and the sensor SA50 is smaller, the air flow in the measurement flow channel 32 is less likely to be disturbed, and the detection accuracy of the flow rate sensor 22 is likely to be improved. Therefore, since the housing partition 131 is provided at a position as close as possible to the housing flow path surface 135, the detection accuracy of the flow rate sensor 22 can be improved.

According to this embodiment, the accommodation side angle θ12 is larger than the flow path side angle θ11. With this configuration, when the sensor SA50 is inserted into the SA housing area 150 of the first housing portion 151, the housing partition 131 is crushed and deformed so as to be folded or collapsed toward the SA housing area 150 side. It's getting easier. Therefore, when the housing partition 131 is deformed and brought into close contact with the outer surface of the sensor SA50, it is less likely that the crushed residue of the housing partition 131 will unintentionally enter the measurement flow path 32. Therefore, it is possible to prevent the detection accuracy of the flow rate sensor 22 from being deteriorated due to the crushed dust coming into contact with or adhering to the flow rate sensor 22 in the measurement flow path 32.

According to the present embodiment, the housing partition 131 provided on the housing step surface 137 is in contact with the SA step surface 147. In this configuration, since the housing step surface 137 and the SA step surface 147 both intersect in the height direction Y and face each other, when the sensor SA50 is inserted into the first housing portion 151, the SA step surface is formed. The surface 147 is hooked on the housing partition 131. Therefore, the housing partition 131 can be brought into close contact with the SA step surface 147 by simply pushing the sensor SA50 toward the measurement flow path 32 and into the first housing 151. As a result, the measurement flow path 32 and the SA accommodation area 150 can be reliably partitioned by the housing partition 131, and an increase in the work load when the sensor SA50 is assembled to the first housing part 151 can be suppressed.

In the present embodiment, the housing step surface 137 of the first housing portion 151 faces the housing opening 151a side. With this configuration, the SA step surface 147 of the sensor SA50 can be pressed against the housing step surface 137 by simply pushing the sensor SA50 inserted into the SA accommodation area 150 from the housing opening 151a toward the measurement flow path 32. .. Therefore, it is possible to realize a configuration in which the housing partition 131 of the SA step surface 147 is easily brought into close contact with the housing step surface 137.

<Explanation of Group D>
As shown in FIG. 22 and FIG. 23, the measurement flow path 32 is curved so that the portion between the measurement inlet 35 and the measurement outlet 36 bulges toward the flow rate sensor 22, and has a U shape as a whole. There is. In the measurement channel 32, the measurement inlet 35 and the measurement outlet 36 are arranged in the depth direction Z. In this case, the depth direction Z corresponds to the arrangement direction, and the height direction Y is orthogonal to the depth direction Z. In the measurement flow path 32, a portion between the measurement inlet 35 and the measurement outlet 36 is curved so as to bulge in the height direction Y toward the base end side of the housing.

The inner surface of the housing 21 has an outer measurement curved surface 401 and an inner measurement curved surface 402. The outer measurement curved surface 401 and the inner measurement curved surface 402 extend along the center line CL4 of the measurement flow path 32. The inner surface of the housing 21 has the front measurement wall surface 103 and the back measurement wall surface 104 as described above, in addition to the outer measurement curved surface 401 and the inner measurement curved surface 402. The outer measurement curved surface 401 and the inner measurement curved surface 402 are arranged in the directions Y and Z orthogonal to the width direction X, and face each other via the front measurement wall surface 103 and the back measurement wall surface 104.

The outer measurement curved surface 401 forms the measurement flow channel 32 from the outside of the curve, and is provided on the outer peripheral side of the measurement flow channel 32 and the flow rate sensor 22. The outer measurement curved surface 401 is bridged over the measurement inlet 35 and the measurement outlet 36. The outer measurement curved surface 401 is curved in a concave shape such that the portion between the measurement inlet 35 and the measurement outlet 36 is recessed toward the flow sensor 22 side as a whole. The outer measurement curved surface 401 includes the measurement ceiling surface 102 and the SA insertion hole 107 is provided.

The inner measurement curved surface 402 forms the measurement channel 32 from the inside of the curve, and is provided on the inner peripheral side of the measurement channel 32. The inner measurement curved surface 402 extends over the measurement inlet 35 and the measurement outlet 36. The inner measurement curved surface 402 is curved so that the portion between the measurement inlet 35 and the measurement outlet 36 bulges toward the flow rate sensor 22 as a whole. The inner measurement curved surface 402 does not have a recessed portion toward the side opposite to the outer measurement curved surface 401, and the whole is curved in a convex shape so as to bulge toward the outer measurement curved surface 401. The inner measurement curved surface 402 includes the measurement floor surface 101.

As shown in FIG. 23, the measurement flow path 32 has a sensor path 405, an upstream curved path 406, and a downstream curved path 407. The sensor path 405 is a portion of the measurement flow path 32 where the flow rate sensor 22 is provided. The sensor path 405 extends straight in the depth direction Z, and extends in the mainstream direction parallel to the angle setting surface 27a of the flange portion 27. The upstream curved path 406 and the downstream curved path 407 are arranged in the depth direction Z, and the sensor path 405 is provided between the upstream curved path 406 and the downstream curved path 407, and connects these curved paths 406 and 407. ing.

The surface of the housing 21 forming the sensor path 405 includes at least a part of the measurement floor surface 101. In this embodiment, the length dimension of the sensor path 405 in the depth direction Z is defined by the measurement floor surface 101. Specifically, the upstream end of the sensor floor 405 includes the upstream end of the measurement floor surface 101, and the downstream end of the sensor path 405 includes the downstream end of the measurement floor surface 101. In this case, the length dimension of the sensor path 405 in the depth direction Z is the same as the length dimension of the measurement floor surface 101. In addition to at least a part of the measurement floor surface 101, a part of the measurement ceiling surface 102, a part of the front measurement wall surface 103, and a part of the back measurement wall surface 104 are formed on the surface of the housing 21 where the sensor path 405 is formed. Parts are included. In the present embodiment, the measurement floor surface 101 extends straight in the depth direction Z, and the fact that the measurement floor surface 101 extends straight in this manner is referred to as the sensor path 405 extending straight.

The upstream curved path 406 extends from the sensor path 405 to the measurement entrance 35 in the measurement flow path 32, and is provided between the sensor path 405 and the measurement entrance 35. The upstream curved path 406 is curved in the housing 21 so as to extend from the sensor path 405 toward the measurement inlet 35. In the upstream curved path 406, the downstream end thereof is opened toward the sensor path 405 in the depth direction Z, while the upstream end thereof is opened toward the measurement inlet 35 in the height direction Y. In this way, in the upstream curved path 406, the opening direction of the upstream end portion and the opening direction of the downstream end portion intersect, and the intersecting angle is 90 degrees, for example. A part of the front measurement wall surface 103 and a part of the back measurement wall surface 104 are included on the inner surface of the upstream curved path 406.

The downstream curved path 407 extends from the sensor path 405 to the measurement outlet 36 in the measurement flow path 32, and is provided between the sensor path 405 and the measurement outlet 36. The downstream curved path 407 is curved in the housing 21 so as to extend from the sensor path 405 toward the measurement outlet 36. In the downstream curved path 407, the upstream end thereof is opened in the depth direction Z toward the sensor path 405, while the downstream end thereof is opened in the height direction Y toward the measurement outlet 36. In this way, in the downstream curved path 407, the opening direction of the upstream end intersects with the opening direction of the downstream end, as in the upstream curved path 406, and the intersecting angle is 90 degrees, for example. .. The inner surface of the downstream curved path 407 includes a part of the front measurement wall surface 103 and a part of the back measurement wall surface 104.

In the measurement flow path 32, the sensor path 405 is included in the detection measurement path 353. The upstream curved path 406 is provided at a position straddling the boundary between the guide measurement path 352 and the detection measurement path 353 in the height direction Y. In this case, the upstream curved path 406 has a part of the guide measurement path 352 and a part of the detection measurement path 353. The downstream curved path 407 is provided at a position straddling the boundary portion between the detection measurement path 353 and the discharge measurement path 354 in the height direction Y. In this case, it has a part of the detection measurement path 353 and a part of the discharge measurement path 354.

The inner surface of the housing 21 has an upstream outer curved surface 411 and an upstream inner curved surface 415 as surfaces forming the upstream curved path 406. The upstream outer curved surface 411 forms the upstream curved path 406 from the outside of the curve, and is provided on the outer peripheral side of the upstream curved path 406. The upstream outer curved surface 411 extends so as to be recessed along the center line CL4 of the measurement flow path 32, and is curved so as to be continuously bent along the center line CL4. The upstream outer curved surface 411 is extended over the upstream end portion and the downstream end portion of the upstream curved passage 406, and corresponds to the upstream outer curved surface.

The upstream inward curved surface 415 forms the upstream curved path 406 from the inside of the curve, and is provided on the inner peripheral side of the upstream curved path 406. The upstream inwardly curved surface 415 extends so as to bulge along the center line CL4 of the measurement flow path 32, and is curved so as to continuously bend along the center line CL4. The upstream inwardly curved surface 415 extends over the upstream end portion and the downstream end portion of the upstream curved passage 406 and corresponds to the upstream inward curved surface. It should be noted that the inner surface of the housing 21 has a part of the front measurement wall surface 103 and a part of the back measurement wall surface 104 in addition to the upstream outer curved surface 411 and the upstream inner curved surface 415 as surfaces forming the upstream curved path 406. Have

The inner surface of the housing 21 has a downstream outer curved surface 421 and a downstream inner curved surface 425 as surfaces forming the downstream curved path 407. The downstream outer curved surface 421 forms the downstream curved path 407 from the outside of the curve, and is provided on the outer peripheral side of the downstream curved path 407. The downstream outer curved surface 421 extends along the center line CL4 of the measurement flow path 32 and is bent at a predetermined angle along the center line CL4. The bending angle of the downstream outer curved surface 421 is, for example, 90 degrees.

The downstream outer curved surface 421 has a downstream outer lateral surface 422, a downstream outer vertical surface 423, and a downstream outer corner 424. The downstream outer lateral surface 422 extends straight from the upstream end of the downstream curved path 407 toward the downstream side in the depth direction Z. The downstream outer vertical surface 423 extends straight from the downstream end of the downstream curved path 407 toward the upstream side in the height direction Y. The downstream outer horizontal surface 422 and the downstream outer vertical surface 423 are connected to each other, and form a downstream outer entrance corner portion 424 as an entrance corner portion that is inwardly interdigitated with each other. The downstream outside entry corner portion 424 has a shape in which the downstream outside curved surface 421 is bent at a substantially right angle.

The downstream inner curved surface 425 forms the downstream curved path 407 from the inside of the curve, and is provided on the inner peripheral side of the downstream curved path 407. The downstream inner curved surface 425 extends so as to bulge along the center line CL4 of the measurement flow path 32, and is curved so as to continuously bend along the center line CL4. The downstream inwardly curved surface 425 extends over the upstream end and the downstream end of the downstream inwardly curved passage 407 and corresponds to the downstream inwardly curved surface. The inner surface of the housing 21 forms a part of the front measurement wall surface 103 and a part of the back measurement wall surface 104 in addition to the downstream outer bending surface 421 and the downstream inner bending surface 425 as surfaces forming the downstream bending path 407. Have

In the measurement flow path 32, the outer measurement curved surface 401 includes an upstream outer curved surface 411 and a downstream outer curved surface 421. Each of the upstream outer curved surface 411 and the downstream outer curved surface 421 includes a part of the measurement ceiling surface 102. The inner measurement curved surface 402 includes an upstream inner curved surface 415 and a downstream inner curved surface 425 in addition to the above-described measurement floor surface 101.

In the measurement flow channel 32, the degree of swelling of the downstream inner curved surface 425 toward the side where the measurement channel 32 is expanded is smaller than the degree of swelling of the upstream inner curved surface 415 toward the side where the measurement channel 32 is expanded. There is. Specifically, the length dimension of the downstream inner curved surface 425 is larger than the length dimension of the upstream inner curved surface 415 in the direction in which the centerline CL4 of the measurement flow path 32 extends. In this case, the radius of curvature R32 of the downstream inner curved surface 425 is larger than the radius of curvature R31 of the upstream inner curved surface 415. That is, the relationship of R32>R31 is established. In other words, the bend of the downstream inner curved surface 425 is looser than the bend of the upstream inner curved surface 415.

In the measurement flow channel 32, the degree of depression of the downstream outer curved surface 421 toward the side where the measurement channel 32 is expanded becomes larger than the degree of depression of the upstream outer curved surface 411 toward the side where the measurement channel 32 is expanded. There is. Specifically, the downstream outer curved surface 421 is bent at a right angle, whereas the upstream outer curved surface 411 is curved. In this case, in the direction in which the center line CL4 of the measurement flow path 32 extends, the length dimension of the bent portion of the downstream outer curved surface 421 is a very small value and smaller than the length dimension of the upstream outer curved surface 411. Has become. If the radius of curvature can be calculated for the bent portion of the downstream outer curved surface 421, this radius of curvature is substantially zero, which is smaller than the radius of curvature R33 of the upstream outer curved surface 411. In this case, the curve of the downstream outer curved surface 421 is tighter than the curve of the upstream outer curved surface 411.

In the upstream curved path 406, the degree of depression of the upstream outer curved surface 411 toward the side that expands the measurement flow channel 32 is smaller than the degree of swelling of the upstream inner curved surface 415 toward the side that expands the measurement flow channel 32. There is. Specifically, the length dimension of the upstream outer curved surface 411 is larger than the length dimension of the upstream inner curved surface 415 in the direction in which the center line CL4 of the measurement flow path 32 extends. In this case, the radius of curvature R33 of the upstream outer curved surface 411 is larger than the radius of curvature R31 of the upstream inner curved surface 415. That is, the relationship of R33>R31 is established.

In the downstream curved path 407, the degree of depression of the downstream outer curved surface 421 toward the side that expands the measurement flow channel 32 becomes larger than the degree of swelling of the downstream inner curved surface 425 toward the side that expands the measurement flow channel 32. There is. Specifically, the length dimension of the downstream outer curved surface 421 is smaller than the length dimension of the downstream inner curved surface 425 in the direction in which the center line CL4 of the measurement flow path 32 extends.

In the downstream curved path 407, since the degree of depression of the downstream outer curved surface 421 is larger than the degree of swelling of the downstream inner curved surface 425, the cross sectional area of the downstream curved path 407 in the cross sectional area S4 of the measurement flow channel 32 is It is getting as large as possible. Specifically, in the direction orthogonal to both the center line CL4 of the measurement flow path 32 and the width direction X, the distance L35b between the downstream outer curved surface 421 and the downstream inner curved surface 425 is equal to the upstream outer curved surface 411. It is larger than the separation distance L35a from the inner curved surface 415. That is, the relationship of L35b>L35a is established.

The separation distance L35b between the downstream outer curved surface 421 and the downstream inner curved surface 425 is the distance at the portion where the downstream outer curved surface 421 and the downstream inner curved surface 425 are most distant from each other in the downstream curved path 407. The portion where the downstream outer curved surface 421 and the downstream inner curved surface 425 are most distant from each other is, for example, a portion where the downstream outer corner 424 of the downstream outer curved surface 421 and the central portion of the downstream inner curved surface 425 face each other. Further, the separation distance L35a between the upstream outer curved surface 411 and the upstream inner curved surface 415 is a separation distance in the portion where the upstream outer curved surface 411 and the upstream inner curved surface 415 are most distant from each other in the upstream curved path 406. A portion where the upstream outer curved surface 411 and the upstream inner curved surface 415 are most distant from each other is, for example, a portion where the central portion of the upstream outer curved surface 411 and the central portion of the upstream inner curved surface 415 face each other.

Regarding the measurement flow path 32, the line CL31 is assumed as a virtual straight line that passes through the flow rate sensor 22 and extends in the depth direction Z. The line CL31 passes through the center CO1 of the heating resistor 71 of the flow rate sensor 22 and is orthogonal to both the center lines CL1 and CL5 of the heating resistor 71. Regarding the line CL31, the depth direction Z corresponds to the line direction of the upstream curved path 406 and the downstream curved path 407. In the sensor path 405, the line CL31 and the center line CL4 of the measurement flow path 32 extend in parallel. The line CL31 extends parallel to the angle setting surface 27a of the housing 21.

The line CL31 passes through the sensor path 405, the upstream curved path 406, and the downstream curved path 407, respectively, and intersects the upstream outer curved surface 411 and the downstream outer curved surface 421, respectively. On the downstream outer curved surface 421, the line CL31 intersects with the downstream outer vertical surface 423. The sensor path 405 extends straight along the line CL31. On the line CL31, the separation distance L31b between the flow rate sensor 22 and the downstream outer curved surface 421 is larger than the separation distance L31a between the flow rate sensor 22 and the upstream outer curved surface 411. That is, the relationship of L31b>L31a is established. As described above, the flow rate sensor 22 is provided at a position near the upstream outer curved surface 411. The distances L31a and L31b are set to the center line CL5 of the heating resistor 71.

In the sensor SA50, since the sensor support portion 51 is provided at the position near the upstream outer curved surface 411, the flow rate sensor 22 is provided at the position near the upstream outer curved surface 411. On the line CL31, the separation distance L32b between the sensor support portion 51 and the downstream outer curved surface 421 is larger than the separation distance L32a between the sensor support portion 51 and the upstream outer curved surface 411. That is, the relationship of L32b>L32a is established. In addition, in the measurement flow path 32, the distance between the sensor support portion 51 in the depth direction Z and the upstream outer curved surface 411 is the distance between the sensor support portion 51 in the depth direction Z and the outside of the downstream side even in a portion that is not on the line CL31. It is larger than the distance from the curved surface 421.

In FIG. 23, the distance between the upstream outer curved surface 411 and the portion of the mold upstream surface 55c of the sensor support portion 51 through which the line CL31 passes is defined as the distance L32a. Further, the separation distance between the portion of the sensor support portion 51 on the mold downstream surface 55d through which the line CL31 passes and the downstream outer curved surface 421 is defined as a separation distance L32b.

The sensor path 405 is provided at a position near the upstream outer curved surface 411 between the upstream outer curved surface 411 and the downstream outer curved surface 421. In this case, on the line L31, the separation distance L33b between the sensor path 405 and the downstream outer curved surface 421 is larger than the separation distance L33a between the sensor path 405 and the upstream outer curved surface 411. That is, the relationship of L33b>L33a is established.

The flow rate sensor 22 is provided at a position near the upstream curved path 406 in the sensor path 405. In this case, on the line L31, the distance L34b between the flow rate sensor 22 and the downstream curved path 407 is larger than the distance L34a between the flow rate sensor 22 and the upstream curved path 406. That is, the relationship of L34b>L34a is established. The sum of the distance L34a and the distance L34b is the length of the sensor path 405 in the depth direction Z.

As described above, the housing 21 has the throttle portions 111 and 112 shown in FIGS. 24 and 25. These narrowed portions 111 and 112 are provided on the measurement wall surfaces 103 and 104, and form a part of the measurement wall surfaces 103 and 104. 24 and 25 show the aligned section CS41. The aligned section CS41 is a section that extends along the aligned line CL41 and extends in the direction in which the measurement wall surfaces 103 and 104 are aligned. Further, the aligned cross section CS41 is orthogonal to the height direction Y.

The front measurement wall surface 103 has a front stop surface 431, a front expansion surface 432, a front stop upstream surface 433, and a front expansion downstream surface 434. The front narrowing surface 431 and the front widening surface 432 are formed by the front narrowing portion 111 and are included in the outer surface of the front narrowing portion 111. That is, the front narrowing portion 111 has the front narrowing surface 431 and the front expanding surface 432. In the front narrowing portion 111, the front narrowing surface 431 extends in the depth direction Z from the front top portion 111a toward the upstream curved path 406, and the table expansion surface 432 extends from the front top portion 111a toward the downstream curved path 407 in the depth direction Z. Extends to. The front top 111a is a boundary between the front stop surface 431 and the front expansion surface 432.

The front stop surface 431 is inclined with respect to the center line CL4 of the measurement flow path 32 in the detection measurement path 353, and faces the upstream outer curved surface 411 side. The front throttle surface 431 gradually reduces and throttles the measurement flow passage 32 from the measurement inlet 35 toward the flow rate sensor 22. The cross-sectional area S4 of the measurement flow path 32 gradually decreases from the upstream end of the front throttle surface 431 toward the front top 111a. The front throttle surface 431 is curved so that the portion between the upstream end portion and the downstream end portion thereof bulges toward the center line CL4 of the measurement flow channel 32.

The front expansion surface 432 is inclined with respect to the center line CL4 of the measurement flow path 32 in the detection measurement path 353, and faces the downstream outer curved surface 421 side. The front expansion surface 432 gradually expands the measurement flow path 32 from the flow sensor 22 side toward the measurement outlet 36. The cross-sectional area S4 of the measurement flow path 32 gradually increases from the front top 111a toward the downstream end of the front expansion surface 432. The front expansion surface 432 is curved so that the portion between the upstream end portion and the downstream end portion thereof bulges toward the center line CL4 of the measurement flow channel 32.

The front stop surface 433 extends straight from the upstream end of the front stop surface 431 toward the measurement inlet 35 in parallel with the line CL31. The front throttle upstream surface 433 is provided between the upstream outer curved surface 411 and the front throttle surface 431 in the upstream curved path 406, and extends over the upstream outer curved surface 411 and the front throttle surface 431. The table expansion downstream surface 434 extends straight from the downstream end of the table expansion surface 432 toward the measurement outlet 36 in parallel with the line CL31. The front expanded downstream surface 434 is provided between the downstream outer curved surface 421 and the front expanded surface 432 in the downstream curved path 407, and extends over the downstream outer curved surface 421 and the front expanded surface 432. The front stop upstream surface 433 and the front expansion downstream surface 434 are arranged in the depth direction Z and are flush with each other because the positions in the width direction X overlap.

The back measurement wall surface 104 has a back drawing surface 441, a back expanding surface 442, a back drawing upstream surface 443, and a back expanding downstream surface 444. The back drawn surface 441 and the back expanded surface 442 are formed by the back drawn portion 112 and are included in the outer surface of the back drawn portion 112. That is, the back drawn portion 112 has the back drawn surface 441 and the back expanded surface 442. In the back drawn portion 112, the back drawn surface 441 extends in the depth direction Z from the back top portion 112a toward the upstream curved path 406, and the back expanded surface 442 extends from the back top portion 112a toward the downstream curved path 407 in the depth direction Z. Extends to. The back top 112a is a boundary between the back drawing surface 441 and the back expanding surface 442.

The back throttle surface 441 is inclined with respect to the center line CL4 of the measurement flow path 32 in the detection measurement path 353, and faces the upstream outer curved surface 411 side. The back throttle surface 441 gradually reduces and narrows the measurement flow passage 32 from the measurement inlet 35 toward the flow rate sensor 22. The cross-sectional area S4 of the measurement flow path 32 gradually decreases from the upstream end of the back throttle surface 441 toward the back top 112a. The back throttle surface 441 is curved so that the portion between the upstream end portion and the downstream end portion thereof bulges toward the center line CL4 of the measurement flow channel 32.

The back expansion surface 442 is inclined with respect to the center line CL4 of the measurement flow path 32 in the detection measurement path 353, and faces the downstream outer curved surface 421 side. The back expansion surface 442 gradually expands the measurement flow path 32 from the flow sensor 22 side toward the measurement outlet 36. The cross-sectional area S4 of the measurement flow channel 32 gradually increases from the back top 112a toward the downstream end of the back expanded surface 442. The back expansion surface 442 is curved so that the portion between the upstream end and the downstream end thereof bulges toward the center line CL4 of the measurement flow path 32.

The back diaphragm upstream surface 443 extends straight from the upstream end of the back diaphragm surface 441 toward the measurement inlet 35 in parallel with the line CL31. The back stop upstream surface 443 is provided between the upstream outer curved surface 411 and the front diaphragm surface 431 in the upstream curved path 406, and extends over the upstream outer curved surface 411 and the front diaphragm surface 431. The back expansion downstream surface 444 extends straight from the downstream end of the back expansion surface 442 toward the measurement outlet 36 in parallel to the line CL31. The back expanded downstream surface 444 is provided between the downstream outer curved surface 421 and the back expanded surface 442 in the downstream curved path 407, and extends over the downstream outer curved surface 421 and the back expanded surface 442. The back diaphragm upstream surface 443 and the back expansion downstream surface 444 are arranged in the depth direction Z and are flush with each other because the positions in the width direction X overlap.

The diaphragm units 111 and 112 correspond to the measurement diaphragm unit. The front stop surface 431 and the rear stop surface 441 correspond to the measurement stop surface, and the front expansion surface 432 and the back expansion surface 442 correspond to the measurement expansion surface. As described above, the center CO1 of the heating resistor 71, the front top portion 111a, and the back top portion 112a are arranged in the width direction X, and the front top portion 111a and the back top portion 112a are located on the center line CL5 of the heating resistor 71. Are arranged.

In the depth direction Z in which the line CL31 extends, the length dimension W31a of the front narrowing portion 111 and the length dimension W31b of the back narrowing portion 112 are the same. In the front narrowing portion 111, the length dimension W32a of the front narrowing surface 431 in the depth direction Z is smaller than the length dimension W33a of the front expansion surface 432 in the depth direction Z. In the back drawn portion 112, the length dimension W32b of the back drawn surface 441 in the depth direction Z is smaller than the length dimension W33b of the back expanded surface 442 in the depth direction Z. In the narrowed portions 111 and 112, the length dimension W32a of the front narrowed surface 431 and the length dimension W32b of the back narrowed surface 441 are the same, and the length dimension W33a of the front expanded surface 432 and the back expanded surface 442 are the same. The length dimension W33b is the same.

The front narrowing portion 111 is provided at a position closer to the upstream curved path 406 in the depth direction Z. In this case, the separation distance W34a between the front narrowed portion 111 and the upstream outer curved surface 411 on the line CL31 is larger than the separation distance W35a between the front narrowed portion 111 and the downstream outer curved surface 421. Like the front narrowed portion 111, the back narrowed portion 112 is provided at a position closer to the upstream curved path 406 in the depth direction Z. In this case, the separation distance W34b between the back drawn portion 112 and the upstream outer curved surface 411 is larger than the separation distance W35b between the back drawn portion 112 and the downstream outer curved surface 421 on the line CL31.

As for the positional relationship between the upstream outer curved surface 411 and the throttle portions 111 and 112, the separation distance W34a and the separation distance W34b are the same. As for the positional relationship between the downstream outer curved surface 421 and the throttle portions 111 and 112, the separation distance W35a and the separation distance W35b are the same.

In the measurement flow path 32, the measurement width dimension W1 (see FIG. 15) between the front measurement wall surface 103 and the back measurement wall surface 104 differs depending on the position. The measurement width dimension W1 differs between the sensor path 405, the upstream curved path 406, and the downstream curved path 407, and is not uniform in each of the sensor path 405, the upstream curved path 406, and the downstream curved path 407. .. However, the separation distance D34 between the front throttle upstream surface 433 and the back throttle upstream surface 443 in the upstream curved path 406 is the same as the separation distance D38 between the front expansion downstream surface 434 and the back expansion downstream surface 444 in the downstream curved path 407. It has become.

The sensor support portion 51 is provided in the upstream curved path 406 at a central position between the front diaphragm upstream surface 433 and the back diaphragm upstream surface 443. Here, the centerline CL32 of the sensor SA50 is assumed. The center line CL32 is a straight virtual line that passes through the center of the sensor support portion 51 in the width direction X on the center line CL5 of the heating resistor 71, is orthogonal to the center line CL5, and extends in the depth direction Z. The center line CL32 extends parallel to the line CL31. In this case, in the upstream curved path 406, the distance D31a between the center line CL32 and the front diaphragm upstream surface 433 is the same as the distance D31b between the center line CL32 and the back diaphragm upstream surface 443.

The sensor support portion 51 is provided at the center position between the front expansion downstream surface 434 and the back expansion downstream surface 444 even in the downstream curved path 407. In the downstream curved path 407, the distance D35a between the center line CL32 and the front expansion downstream surface 434 is the same as the distance D35b between the center line CL32 and the back expansion downstream surface 444. As for the positional relationship between the front surface measurement wall surface 103 and the sensor support portion 51, the separation distance D31a and the separation distance D35a are the same. As for the positional relationship between the back measurement wall surface 104 and the sensor support portion 51, the separation distance D31b and the separation distance D35b are the same.

In the front measurement wall surface 103, since the front surface upstream surface 433 and the front surface expansion downstream surface 434 are flush with each other, the protruding dimension of the front surface narrowing portion 111 in the upstream curved path 406 and the surface narrowed surface in the downstream curved path 407. The protrusion size of the portion 111 is the same. Specifically, the protrusion dimension D32a of the front top 111a with respect to the front throttle upstream surface 433 and the protrusion dimension D36a of the front top 111a with respect to the front expansion downstream surface 434 are the same.

The projecting dimension of the front diaphragm surface 431 with respect to the front diaphragm upstream surface 433 gradually increases from the front diaphragm upstream surface 433 toward the front top 111a. This increase rate gradually increases from the front surface upstream surface 433 toward the front top portion 111a, so that the front surface 431 is a curved surface. The projecting dimension of the front expansion surface 432 with respect to the front expansion downstream surface 434 gradually decreases from the front top portion 111a toward the front expansion downstream surface 434. The rate of decrease gradually increases from the surface top portion 111a toward the surface expansion downstream surface 434, so that the surface expansion surface 432 is a curved surface.

As described above, in the front narrowing portion 111, the length dimension W33a of the front expansion surface 432 is larger than the length dimension W32a of the front narrowing surface 431. In this case, the decrease rate of the protrusion dimension of the front expansion surface 432 from the front top portion 111a to the front expansion downstream surface 434 is smaller than the increase rate of the protrusion dimension of the front expansion surface 431 from the front throttle upstream surface 433 to the front top portion 111a. Is also getting smaller. The front stop surface 431 and the front expansion surface 432 are continuous curved surfaces, and the tangent line of the front stop surface 431 and the tangent line of the front expansion surface 432 both extend parallel to the alignment line CL31 at the front top 111a. ..

For the front narrowing portion 111, the ratio of the length dimension W32a of the front narrowing surface 431 and the projection dimension D32a of the front top portion 111a on the narrowing side is referred to as the front narrowing ratio, and the length dimension W33a of the front expanded surface 432 and the front top portion 111a are defined. The ratio with the protrusion dimension D36a on the expansion side is called the front expansion rate. For example, a value obtained by dividing the projecting dimension D32a on the diaphragm side by the length dimension W32a is calculated as the table drawing rate, and a value obtained by dividing the projecting dimension D36a on the expansion side by the length dimension W33a is calculated as the table expansion rate. In this case, the table expansion rate becomes a value smaller than the table reduction rate.

In the back measurement wall surface 104, since the back drawing upstream surface 443 and the back expansion downstream surface 444 are flush with each other, the protruding dimension of the back drawing portion 112 in the upstream curved path 406 and the back drawing in the downstream curved path 407. The protrusion size of the portion 112 is the same. Specifically, the protrusion dimension D32b of the back top portion 112a with respect to the back draw upstream surface 443 and the protrusion dimension D36b of the back top portion 112a with respect to the back expansion downstream surface 444 are the same.

The projecting dimension of the back diaphragm surface 441 with respect to the back diaphragm upstream surface 443 gradually increases from the back diaphragm upstream surface 443 toward the back top 112a. The rate of increase gradually increases from the back stop upstream surface 443 toward the back top 112a, so that the back stop surface 441 is a curved surface. The protruding dimension of the back expansion surface 442 with respect to the back expansion downstream surface 444 gradually decreases from the back top 112 a toward the back expansion downstream surface 444. This decreasing rate gradually increases from the back top 112a toward the back expansion downstream surface 444, so that the back expansion surface 442 is a curved surface.

As described above, in the back drawn portion 112, the length dimension W33b of the back expanded surface 442 is larger than the length dimension W32b of the back drawn surface 441. In this case, the decrease rate of the protruding dimension of the back expansion surface 442 from the back top 112a toward the back expansion downstream surface 444 is smaller than the increase rate of the projection dimension of the back drawing surface 441 from the back draw upstream surface 443 to the back top 112a. Is also getting smaller. The back drawing surface 441 and the back expanding surface 442 are continuous curved surfaces, and the tangent line of the back drawing surface 441 and the tangent line of the back expanding surface 442 both extend parallel to the line CL31 at the back top 112a. ..

Regarding the back drawn portion 112, the ratio of the length dimension W32b of the back drawn surface 441 and the projection dimension D32b of the back top portion 112a on the drawing side is called the front drawing ratio, and the length dimension W33b of the back expanded surface 442 and the back top portion 112a are defined. The ratio to the protrusion dimension D32b on the expansion side is referred to as the front expansion rate. For example, a value obtained by dividing the projection dimension D32b on the diaphragm side by the length dimension W32b is calculated as the back drawing rate, and a value obtained by dividing the projection dimension D32b on the expansion side by the length dimension W33b is calculated as the back expansion rate. In this case, the back expansion rate becomes a value smaller than the back drawing rate.

In the relationship between the front drawing portion 111 and the back drawing portion 112, the front drawing ratio is higher than the back drawing ratio because the projection dimensions D32a and D36a of the front top part 111a are larger than the projection dimensions D32b and D36b of the back top part 112a. And the front-side expansion rate is larger than the back-side expansion rate.

When the rate at which the throttle portions 111 and 112 reduce the measurement flow path 32 is referred to as a reduction rate, this reduction rate is proportional to the reduction rate. For this reason, the larger the front reduction ratio of the front reduction unit 111, the higher the reduction ratio of the table reduction unit 111 that reduces the measurement flow passage 32. For example, the table reduction rate and the table reduction rate have the same value. Similarly, the larger the back draw ratio of the back draw part 112, the greater the back draw ratio at which the back draw part 112 reduces the measurement flow path 32. Therefore, in the present embodiment, the front reduction ratio is higher than the back reduction ratio, so that the front reduction ratio is higher than the back reduction ratio. For example, the back reduction ratio and the back reduction ratio are the same value.

The sensor support portion 51 is provided at the center position between the front measurement wall surface 103 and the back measurement wall surface 104 in the upstream curved path 406 and the downstream curved path 407, whereas it is provided in the sensor path 405 closer to the front measurement wall surface 103. It is provided in the position. This is because the projecting dimension of the front narrowing portion 111 on the front measuring wall surface 103 is larger than the projecting dimension of the back narrowing portion 112 on the back measuring wall surface 104. Specifically, the projection dimensions D32a, D36a of the front top 111a with respect to the front drawing upstream surface 433 and the front expansion downstream surface 434 are larger than the projection dimensions D32b, D36b of the back top 112a with respect to the back drawing upstream surface 443 and the back expansion downstream surface 444. Is also getting bigger. As a result, the distance D33a between the center line CL32 of the sensor support portion 51 and the front top 111a is smaller than the distance D33b between the center line CL32 and the back top 112a.

The housing 21 has a measurement partition 451. The measurement partition section 451 is provided between the guide measurement path 352 and the discharge measurement path 354 in the depth direction Z, and separates the guide measurement path 352 and the discharge measurement path 354. Further, the measurement partitioning portion 451 is provided between the passage channel 31 or the branch measurement passage 351 and the detection measurement passage 353 in the height direction Y, and the passage passage 31 or the branch measurement passage 351 and the passage passage 353 are provided. It is separated from 31. The measurement partition section 451 is extended across the front measurement wall surface 103 and the back measurement wall surface 104 in the width direction X, and forms an inner measurement curved surface 402. The outer surface of the measurement partitioning portion 451 includes inner measurement curved surfaces 402 such as the measurement floor surface 101, the upstream inner curved surface 415, and the downstream inner curved surface 425.

The throttles 111 and 112 extend from the measurement partition 451 toward the measurement ceiling surface 102. The narrowed portions 111 and 112 do not protrude from the measurement partitioning portion 451 in the depth direction Z on either the upstream outer curved surface 411 side or the downstream outer curved surface 421 side. In the depth direction Z, the width dimension of the measurement partition portion 451 is the same as or smaller than the length dimension W31a, W31b of the throttle portions 111, 112. The throttles 111 and 112 are provided between the upstream curved path 406 and the downstream curved path 407. In the present embodiment, the upstream end portions of the throttle portions 111 and 112 are provided in the upstream curved path 406 and the downstream end portions are provided in the downstream curved passage 407. In this configuration as well, the throttle portions 111 and 112 are upstream. It is assumed that it is provided between the curved road 406 and the downstream curved road 407.

As shown in FIGS. 4 to 7, the passage inlet 33 is provided on the housing upstream surface 21c and is open toward the upstream side in the intake passage 12. Therefore, the main flow flowing in the intake passage 12 in the main flow direction easily flows into the passage inlet 33. The passage outlet 34 is provided on the housing downstream surface 21d and is open toward the downstream side in the intake passage 12. For this reason, the air flowing out from the passage outlet 34 is likely to flow downstream in the intake passage 12 together with the main flow.

The measurement outlet 36 is provided on each of the housing front surface 21e and the housing back surface 21f. The housing front surface 21e and the housing back surface 21f extend along the line CL31, and the measurement outlet 36 is opened in a direction orthogonal to the line CL31. Therefore, the main flow flowing in the intake passage 12 in the main flow direction is less likely to flow into the measurement outlet 36, and the air flowing out of the measurement outlet 36 is likely to flow downstream together with the main flow in the intake passage 12. Further, when the main flow passes near the measurement outlet 36 in the intake passage 12, the air near the measurement outlet 36 is pulled into the main flow in the measurement flow path 32, and the air flows from the measurement outlet 36. It becomes easy to flow out. As a result, the air in the measurement flow channel 32 easily flows out from the measurement outlet 36. The width direction X corresponds to the orthogonal direction.

Next, a flow mode of air flowing through the measurement flow channel 32 will be described.

As shown in FIG. 23, the air flowing into the measurement flow path 32 from the passage flow path 31 through the measurement inlet 35 becomes the outer curved flow AF 31 that advances along the outer measurement curved surface 401 and the inner measurement curved surface 402. An inward curving flow AF32 traveling along is included. As described above, in the measurement flow path 32, since the outer measurement curved surface 401 is curved so as to be recessed as a whole, the outer curved flow AF 31 is likely to travel along the outer measurement curved surface 401. Since the inner measurement curved surface 402 is curved so as to bulge as a whole, the inner curved flow AF 32 is likely to travel along the inner measurement curved surface 402. Further, while the outer measurement curved surface 401 and the inner measurement curved surface 402 are curved in the direction orthogonal to the width direction X, the narrowed portions 111 and 112 narrow the measurement flow channel 32 in the width direction X. Therefore, in the measurement flow path 32, the turbulence of the airflow is less likely to occur such that the outer curved flow AF31 and the inner curved flow AF32 are mixed.

The outer curved flow AF31 that has reached the upstream curved path 406 in the measurement flow channel 32 changes its direction by flowing along the upstream outer curved surface 411. In this case, since the upstream outer curved surface 411 is bent more gently than the downstream outer curved surface 421, the upstream outer curved surface 411 is sufficiently loosened, so that the outer curved flow AF31 is swirled. Disturbances are less likely to occur.

As shown in FIG. 25, in the airflow flowing through the measurement flow path 32, the front side outflow AF 33 flowing between the sensor support portion 51 and the front diaphragm surface 431, and the sensor support portion 51 and the back diaphragm surface 441. The back flow AF34 flowing in between is included. Of the curved flows AF31 and AF32, the air that flows along the front measurement wall surface 103 and reaches the throttle portions 111 and 112 is likely to be included in the front side flow AF33, and flows along the back measurement wall surface 104 to reduce the throttle portion 111. , 112 reaching the backflow AF 34 is likely to be included in the backflow AF 34.

On the front side of the sensor support portion 51, the rectification effect of the out-of-plane flow AF33 gradually increases toward the front surface 111a, just as the degree of reduction of the front surface 431 gradually increases toward the front surface 111a. ing. Moreover, since the protrusion dimensions D32a and D36a of the front top portion 111a are larger than the protrusion dimensions D32b and D36b of the back top portion 112a, the rectifying effect of the front throttle surface 431 is sufficiently enhanced. As a result, the front side outflow AF 33, which is sufficiently rectified by the front throttle surface 431 and the sensor support portion 51, reaches the flow rate sensor 22, so that the flow rate detection accuracy of the flow rate sensor 22 tends to be high.

The frontward flow AF 33 is gradually accelerated toward the front top 111a. Then, the front side drift AF 33 is caused by the area between the front narrowing portion 111 and the sensor support portion 51 being expanded by the front expansion surface 432, so that the front top portion 111 a and the sensor support portion 51 are separated from each other. It advances toward the downstream curved path 407 so that it is blown out as a jet flow. Here, when the area between the front expansion surface 432 and the sensor support portion 51 is rapidly expanded, the turbulence such as vortex is likely to occur due to separation of the front offset flow AF33 from the front expansion surface 432. Is concerned. On the other hand, due to the configuration in which the length dimension W33a of the front expansion surface 432 is larger than the length dimension W32a of the front diaphragm surface 431, the area between the front expansion surface 432 and the sensor support portion 51 becomes gentle. It has been extended. Therefore, separation of the out-of-plane flow AF 33 from the surface expansion surface 432 is unlikely to occur, and turbulence such as eddy current is less likely to occur in the downstream side of the surface top 111a.

On the back side of the sensor support portion 51, the degree of squeezing of the back squeezing surface 441 is gradually increased toward the back top portion 112a, so that the rectification effect of the backflow AF34 is gradually increased toward the back top portion 112a. ing. In this case, the backside flow AF34, which has been sufficiently rectified by the back diaphragm surface 441 and the sensor support portion 51, reaches the back top 112a, so the backside flow AF34 is disturbed even after passing through the back top 112a. Hateful.

The backflow AF 34 is gradually accelerated toward the back top 112a. The back side flow AF 34 is generated from between the back top 112 a and the sensor support 51 due to the area between the back narrowing 112 and the sensor support 51 being expanded by the back expansion surface 442. It advances toward the downstream curved path 407 so that it is blown out as a jet flow. Here, if the area between the back expansion surface 442 and the sensor support portion 51 is rapidly expanded, the back side flow AF 34 may be separated from the back expansion surface 442, so that turbulence such as vortex is likely to occur. Is concerned. On the other hand, due to the configuration in which the length dimension W33b of the back extension surface 442 is larger than the length dimension W32b of the back drawing surface 441, the region between the back extension surface 442 and the sensor support portion 51 becomes gentle. It has been extended. Therefore, the backside flow AF34 is less likely to be separated from the back extended surface 442, and the turbulence such as a vortex is less likely to occur on the downstream side of the back top 112a.

It is considered that the front side offset flow AF33 and the back side offset flow AF34 merge at the sensor path 405 and the downstream curved path 407 after passing through the sensor support portion 51. For example, if the flow of the back flow AF34 is disturbed, the air flow is disturbed on the downstream side of the sensor support portion 51, and the front flow AF33 is unlikely to pass between the front throttle portion 111 and the sensor support portion 51. Prone. In this case, there is a concern that the flow rate and flow velocity of the out-of-plane flow AF 33 that passes through the flow rate sensor 22 will be insufficient, and the flow rate detection accuracy of the flow rate sensor 22 will decrease. On the other hand, in the present embodiment, the back side flow AF 34 is rectified by the back narrowing portion 112, so that the back side flow AF 34 that has passed through the sensor support portion 51 is disturbed, so that the back side flow AF 34 is downstream of the sensor support portion 51. The occurrence of turbulence in the air flow is suppressed.

When the front side offset flow AF33 and the back side offset flow AF34 are blown out from between the sensor support portion 51 and the throttle portions 111 and 112 toward the downstream curved path 407, the side offset flow AF33 and AF34 follow the alignment line CL31. And advances toward the downstream outer curved surface 421 as a forward flow. When the offset flows AF33, AF34 hit the downstream outward curved surface 421, the offset flows AF33, AF34 may bounce back on the downstream outward curved surface 421 and flow backward in the measurement flow path 32 in the direction of returning to the flow rate sensor 22 side. I'm worried. In particular, when hitting the downstream outer vertical surface 423, it is considered that the offset flows AF33 and AF34 are likely to flow backward toward the flow rate sensor 22 along the line CL31. When the reverse flow reaches the flow rate sensor 22 against the forward flow, the direction of the air flow detected by the flow rate sensor 22 is opposite to the actual flow, and the detection accuracy of the flow rate sensor 22 decreases. .. Even if the backflow does not reach the flow rate sensor 22, the backflow makes it difficult for the forward flow to flow, so that the flow rate detected by the flow rate sensor 22 becomes smaller than the actual flow rate, and the detection accuracy of the flow rate sensor 22 decreases. I will end up.

On the other hand, in the present embodiment, since the flow rate sensor 22 is provided at a position closer to the upstream outer curved surface 411 than the downstream outer curved surface 421, the flow rate sensor 22 is separated from the downstream outer curved surface 421 as much as possible. In position. In this configuration, the momentum of the offset flows AF33, AF34 is likely to decrease by the time the offset flows AF33, AF34 blown out between the sensor support part 51 and the throttle parts 111, 112 reach the downstream outward curved surface 421. For this reason, even if the offset flows AF33 and AF34 bounce back on the downstream outer curved surface 421 and become a reverse flow, there is no momentum of the reverse flow and it is difficult to reach the flow rate sensor 22. Further, the farther the flow sensor 22 is from the downstream curved outer surface 421, the longer the backflow reaches the flow sensor 22, so that the backflow is reliably suppressed from reaching the flow sensor 22.

Since the imaginary line passing through the flow rate sensor 22 is the line CL31, the air that has passed through the flow rate sensor 22 in the outflow AF33 easily flows along the line CL31. Therefore, by making the separation distance L31b between the flow rate sensor 22 and the downstream outer curved surface 421 on the line CL31 as large as possible, the air that has passed through the flow rate sensor 22 in the front side offflow AF33 is directed to the downstream outer curved surface 421. The distance to reach can be maximized. Here, in the configuration in which the line CL31 passes through the downstream outer vertical surface 423 as in the present embodiment, when the air that has passed through the flow rate sensor 22 hits the downstream outer vertical surface 423 and bounces back, it returns to the flow rate sensor 22 as it is. It is thought that it is easy to regurgitate. Therefore, in the configuration in which the line CL31 passes through the downstream outer vertical surface 423, it is necessary to make the separation distance L31b between the flow sensor 22 and the downstream outer curved surface 421 on the line CL31 as large as possible. It is effective in making it difficult for the backflow to reach.

According to this embodiment described so far, the degree of depression of the downstream outer curved surface 421 is larger than the degree of depression of the upstream outer curved surface 411. In this configuration, the cross-sectional area and volume of the downstream curved path 407 can be maximized by maximizing the degree of depression of the downstream outer curved surface 421, and therefore the pressure when air flows through the downstream curved path 407. The loss can be reduced. As described above, by reducing the pressure loss in the downstream curved path 407, it becomes difficult for the air passing through the flow rate sensor 22 to become clogged in the downstream curved path 407, and the air passing through the flow rate sensor 22 is prevented. Insufficient amount and flow velocity are less likely to occur. For this reason, the flow rate detection accuracy of the flow rate sensor 22 can be reduced, and as a result, the flow rate measurement accuracy of the air flow meter 20 can be improved.

Here, in order to maximize the cross-sectional area and volume of the downstream curved path 407, a method of expanding the downstream curved path 407 in the width direction X and the depth direction Z can be considered. However, in this method, there is a concern that the housing 21 may become large in the width direction X and the depth direction Z. In this case, the air flow in the intake passage 12 is disturbed by the housing 21, and the detection accuracy of the flow rate sensor 22 is likely to deteriorate. Further, in this case, the resin material required for molding the housing 21 increases, and the manufacturing cost of the housing 21 tends to increase.

On the other hand, in the present embodiment, the cross-sectional area and volume of the downstream curved path 407 are maximized by maximizing the degree of depression of the downstream outer curved surface 421, so that the housing 21 can be prevented from becoming large. .. In this case, the flow of air in the intake passage 12 is less likely to be disturbed by the housing 21, so that the detection accuracy of the flow rate sensor 22 can be improved. Further, in this case, since the resin material required for molding the housing 21 can be easily reduced, an increase in cost when manufacturing the housing 21 can be suppressed.

According to the present embodiment, the curved portion of the downstream outer curved surface 421 is formed by the downstream outer corner 424. With this configuration, the degree of depression of the downstream outer curved surface 421 can be maximized in the range where the downstream outer curved surface 421 does not make a detour. That is, it is possible to realize a configuration in which the downstream curved path 407 has the largest cross-sectional area and volume within the range in which the downstream curved path 407 can be expanded due to the shape of the downstream curved surface 421.

According to the present embodiment, the distance L35b between the downstream outer curved surface 421 and the downstream inner curved surface 425 is larger than the distance L35a between the upstream outer curved surface 411 and the upstream inner curved surface 415. With this configuration, it is possible to realize a configuration in which the downstream outer curved surface 421 and the downstream inner curved surface 425 are separated from each other as much as possible in the direction orthogonal to the center line CL4 of the measurement flow path 32. Therefore, even if the downstream curved path 407 and the housing 21 are not expanded in the width direction X, the cross-sectional area and volume of the downstream curved path 407 are maximized due to the positional relationship between the downstream outer curved surface 421 and the downstream inner curved surface 425. can do.

According to this embodiment, the degree of swelling of the downstream inner curved surface 425 is smaller than that of the upstream inner curved surface 415. Therefore, even if the downstream curved path 407 and the housing 21 are not expanded in the width direction X, the cross-sectional area and volume of the downstream curved path 407 can be maximized due to the shape of the downstream inner curved surface 425.

According to this embodiment, since the radius of curvature R32 of the downstream inner curved surface 425 is larger than the radius of curvature R31 of the upstream inner curved surface 415, the degree of swelling of the downstream inner curved surface 425 is greater than the degree of swelling of the upstream inner curved surface 415. A small configuration has been realized. With this configuration, while the degree of swelling of the downstream inner curved surface 425 is minimized, the air that has reached the downstream curved path 407 from the flow sensor 22 side easily flows toward the measurement outlet 36 along the curve of the downstream inner curved surface 425. Become. Therefore, it is possible to suppress that the air stays in the downstream curved path 407 and the pressure loss in the downstream curved path 407 increases by the shape of the downstream inner curved surface 425.

According to the present embodiment, the separation distance L31b between the flow rate sensor 22 and the downstream outer curved surface 421 is larger than the separation distance L31a between the flow sensor 22 and the upstream outer curved surface 411 on the line CL31. With this configuration, the flow rate sensor 22 can be arranged as far as possible from the downstream outer curved surface 421 between the upstream outer curved surface 411 and the downstream outer curved surface 421. Therefore, even if the air that has passed through the flow rate sensor 22 in the measurement flow path 32 hits the downstream outer curved surface 421 and flows back in the direction of returning to the flow rate sensor 22 side, the backflow is difficult to reach the flow rate sensor 22. Further, even if the turbulence of the air flow due to the backflow occurs in the downstream curved path 407, this turbulence is hard to reach the flow rate sensor 22. Therefore, it is possible to suppress a decrease in the accuracy of flow rate detection by the flow rate sensor 22. As a result, the accuracy of measuring the flow rate by the air flow meter 20 can be improved.

Here, in order to maximize the separation distance L31b between the flow rate sensor 22 and the downstream outer curved surface 421, a method of separating the downstream outer curved surface 421 from the flow rate sensor 22 by extending the detection measurement path 353 in the depth direction Z or the like. Is possible. However, with this method, there is a concern that the housing 21 may become large in the depth direction Z. On the other hand, in the present embodiment, the distance L31b between the flow sensor 22 and the downstream outer curved surface 421 is set by setting the position of the flow sensor 22 in the detection measurement path 353 to a position closer to the upstream outer curved surface 411. Since it is made as large as possible, it is possible to avoid an increase in size of the housing 21.

According to this embodiment, the sensor path 405 in which the flow rate sensor 22 is installed extends along the line CL31. In this configuration, the air flowing along the flow rate sensor 22 is likely to travel straight along the line CL31, so that the turbulence of the air flow is less likely to occur around the flow rate sensor 22. In this case, the flow velocity of the air around the flow rate sensor 22 is easily stabilized, so that the detection accuracy of the flow rate sensor 22 can be improved. Moreover, since the flow rate sensor 22 is arranged at a position as far as possible from the downstream outer curved surface 421, the turbulence of the air flow in the downstream curved path 407 is less likely to be imparted to the flow rate sensor 22, so that the flow rate sensor 22 periphery It is possible to more reliably suppress the turbulence of the air flow in. In this case, the flow velocity of air around the flow rate sensor 22 is more easily stabilized, so that the detection accuracy of the flow rate sensor 22 can be further increased.

According to the present embodiment, in the sensor path 405 extending along the line CL31, the flow rate sensor 22 is provided at a position closer to the upstream curved path 406 than the downstream curved path 407. With this configuration, in the sensor path 405, turbulence of air around the flow rate sensor 22 is suppressed and the flow velocity of air is stabilized, and then the flow rate sensor 22 can be arranged at a position as far as possible from the downstream outer curved surface 421. ..

According to the present embodiment, the sensor support portion 51 is provided on the line CL31 at a position closer to the upstream outer curved surface 411 than the downstream curved path 407. With this configuration, since the sensor support portion 51 can be arranged at a position as far as possible from the downstream curved path 407, the airflow flowing into the downstream curved path 407 is likely to be disturbed by the presence of the sensor support portion 51. Can be suppressed.

According to the present embodiment, the line CL31 passes through the downstream outer vertical surface 423 of the downstream outer curved surface 421. In this configuration, since the downstream outer vertical surface 423 extends straight from the downstream end of the downstream curved path 407 toward the upstream side, a portion of the downstream outer curved surface 421 farthest from the flow rate sensor 22 is formed. The line CL31 passes through. In this way, by making the distance required for the air passing through the flow rate sensor 22 to reach the downstream outer curved surface 421 as large as possible, the air passing through the flow rate sensor 22 bounces at the downstream outer curved surface 421 and flows as a backflow. It is possible to reliably suppress the return to the sensor 22.

According to this embodiment, since the downstream inner curved surface 425 is curved, the separation distance L35b between the downstream outer curved surface 421 and the downstream inner curved surface 425 in the downstream curved path 407 can be maximized. In this configuration, since the downstream inner curved surface 425 is curved and the cross-sectional area of the downstream curved path 407 is maximized, the volume of the downstream curved path 407 is maximized. Therefore, even if turbulence of the air flow occurs in the downstream curved path 407 due to rebound of air on the downstream outer curved surface 421 or the like, the air in the downstream curved path 407 easily flows toward the measurement outlet 36 due to this turbulence. ing. Therefore, it is possible to more reliably prevent the backflow from reaching the flow rate sensor 22 from the downstream curved path 407.

According to this embodiment, the throttle portions 111 and 112 that gradually narrow the measurement flow passage 32 and then gradually expand are provided between the upstream end portion of the upstream curved passage 406 and the downstream end portion of the downstream curved passage 407. ing. In this configuration, the air that has passed through the throttle portions 111 and 112 is jetted out as a jet flow toward the downstream curved path 407, and there is a concern that the downstream outer curved surface 421 easily bounces. Therefore, it is effective to provide the flow rate sensor 22 at a position as far as possible from the downstream outer curved surface 421 in order to prevent the air rebounded at the downstream outer curved surface 421 from reaching the flow rate sensor 22.

According to the present embodiment, the length dimensions W33a and W33b of the expansion surfaces 432 and 442 in the throttle portions 111 and 112 are larger than the length dimension W32a of the throttle surfaces 431 and 441. In this configuration, the degree of expansion and the expansion rate of the measurement flow path 32 by the expansion surfaces 432 and 442 are gentle so that the turbulence such as the separation of the air flow does not occur due to the rapid expansion of the measurement flow path 32. As a result, it is possible to prevent the flow in the downstream curved path 407 from being disturbed by the air that has passed through the throttle portions 111 and 112.

According to the present embodiment, the throttle portions 111 and 112 are provided at positions closer to the upstream outer curved surface 411 than the downstream outer curved surface 421. With this configuration, the narrowed portions 111 and 112 can be arranged as far as possible from the downstream outer curved surface 421 between the upstream outer curved surface 411 and the downstream outer curved surface 421. Therefore, without enlarging the housing 21, it is possible to reduce the momentum that the air passing through the throttle portions 111 and 112 hits the downstream outer curved surface 421.

According to the present embodiment, the front measurement wall surface 103 and the back measurement wall surface 104 face each other with the upstream curved path 406 interposed therebetween, and the measurement wall surfaces 103 and 104 are provided with the narrowed portions 111 and 112. In this configuration, the direction in which the air bends in the upstream curved path 406 and the direction in which the air is throttled by the throttles 111 and 112 are substantially orthogonal to each other. Therefore, when the airflow such as the outer curved flow AF31 flowing along the upstream outer curved surface 411 and the airflow such as the inner curved flow AF32 flowing along the upstream inner curved surface 415 pass through the throttle portions 111 and 112. It is unlikely that turbulence will occur as a result of mixing. Therefore, it is possible to enhance the air flow rectifying effect by the throttle portions 111 and 112.

According to this embodiment, the upstream curved surface 411 is curved. In this configuration, since the direction of the airflow such as the outer curving flow AF31 flowing along the outer measurement curving surface 401 is gradually changed by the upstream outer curving surface 411, the airflow flowing along the upstream outer curving surface 411 is less likely to be disturbed. .. Therefore, the air that reaches the flow rate sensor 22 such as the outward curved flow AF31 is less likely to be disturbed, and the air blown toward the downstream curved path 407 is also less likely to be disturbed.

According to the present embodiment, the inner measurement curved surface 402 extending along the measurement flow path 32 is curved so as to bulge toward the flow rate sensor 22 as a whole. In this configuration, since the concave portion is not formed on the inner measurement curved surface 402, it is unlikely that air such as the inner curved flow AF32 flowing along the inner measurement curved surface 402 enters the concave portion to cause turbulence such as vortex. Has become. Therefore, air such as the inward curved flow AF32 that reaches the flow rate sensor 22 is less likely to be disturbed, and the air blown toward the downstream curved path 407 is also less likely to be disturbed.

According to the present embodiment, the measurement outlet 36 is provided on the housing front surface 201e and the housing back surface 21f of the outer surface of the housing 21. In this configuration, when the air flows along the housing front surface 21e and the housing rear surface 21f along the measurement outlet 36 in the intake passage 12, the air in the measurement flow path 32 flows out from the measurement outlet 36 as if it is pulled by this air. The phenomenon of, is likely to occur. Therefore, even if turbulence of the air flow occurs in the downstream curved path 407 due to bounce of air or the like, the air flowing outside the housing 21 in the intake passage 12 is used to measure the turbulence of the air flow from the downstream curved path 407 to the measurement outlet 36. Air can easily flow toward.

<Explanation of configuration group E>
As shown in FIGS. 10, 11, and 26, the mold upstream surface 55c of the sensor SA50 has a mold upstream inclined surface 471. The mold upstream inclined surface 471 extends obliquely and straight from the upstream end portion of the mold front end surface 55a toward the mold base end surface 55b, and corresponds to an upstream inclined portion inclined with respect to the height direction Y. Further, the mold downstream surface 55d has a mold downstream inclined surface 472. The mold downstream inclined surface 472 obliquely extends from the downstream end portion of the mold front end surface 55a toward the mold base end surface 55b, and corresponds to a downstream inclined portion inclined with respect to the height direction Y. The mold upstream inclined surface 471 and the mold downstream inclined surface 472 are both inclined with respect to the aligned section CS41, and are in a state of straddling the aligned section CS41 in the height direction Y.

As shown in FIGS. 26 and 27, the front upstream end 111b, which is the upstream end of the front narrowed portion 111, is arranged at the boundary between the front narrowed surface 431 and the front narrowed surface 433. The front downstream end 111c, which is the downstream end of the front narrowed portion 111, is arranged at the boundary between the front expansion surface 432 and the front expansion downstream surface 434. The back upstream end 112 b, which is the upstream end of the back drawn portion 112, is arranged at the boundary between the back drawn surface 441 and the back drawn upstream surface 443. The back downstream end 112 c, which is the 0 downstream end of the back narrowing portion 112, is arranged at the boundary between the back expanded surface 442 and the back expanded downstream surface 444.

The mold upstream inclined surface 471 of the sensor SA50 is arranged at a position straddling both the front upstream end portion 111b of the front narrowed portion 111 and the back upstream end portion 112b of the back narrowed portion 112 in the depth direction Z. Here, an end portion of the mold upstream inclined surface 471 on the mold front end side is referred to as a front end side end portion 471a, and a mold base end side end portion is referred to as a base end side end portion 471b. In this case, the front end portion 471a is provided downstream of the upstream end portions 111b and 112b of the narrowed portions 111 and 112 in the depth direction Z. Further, the base-side end portion 471b of the mold upstream inclined surface 471 is provided on the upstream side of the narrowed portion 111 and the back narrowed portion 112 in the depth direction Z. The upstream end portions 111b and 112b of the narrowed portions 111 and 112 are provided at positions closer to the front end portion 471a than the base end portion 471b of the mold upstream inclined surface 471 in the depth direction Z.

The mold downstream inclined surface 472 is arranged at a position straddling both the front downstream end portion 111c of the front narrowed portion 111 and the back downstream end portion 112c of the back narrowed portion 112 in the depth direction Z. Here, the end on the mold front end side of the mold downstream inclined surface 472 is referred to as the front end end 472a, and the end on the mold base end side is referred to as the base end end 472b. In this case, the front end portion 472a is provided on the upstream side of the downstream end portions 111c and 112c of the narrowed portions 111 and 112 in the depth direction Z. The base end 472b of the mold downstream inclined surface 472 is provided on the downstream side of the narrowed portions 111 and 112 in the depth direction Z. The downstream end portions 111c and 112c of the narrowed portions 111 and 112 are provided in the depth direction Z at positions closer to the proximal end portion 471b than the distal end portion 472a of the mold downstream inclined surface 472.

As shown in FIG. 27, in the array cross section CS41 of the air flow meter 20, the mold upstream inclined surface 471 of the mold upstream surface 55c is provided on the upstream side of the throttle portions 111 and 112. In this case, the mold upstream inclined surface 471 is provided between the upstream end portions 111b and 112b of the narrowed portions 111 and 112 and the upstream outer curved surface 411. In the aligned section CS41, the separation distance W41a between the mold upstream inclined surface 471 and the front drawn portion 111 in the depth direction Z is the same as the separation distance W41b between the mold upstream inclined surface 471 and the back drawn portion 112. Further, the separation distance W41a is smaller than the length dimension W32a of the front diaphragm surface 431, and the separation distance W41b is smaller than the length dimension W32b of the back diaphragm surface 441.

Further, in the aligned section CS41, the mold downstream inclined surface 472 of the mold downstream surface 55d is provided on the upstream side of the downstream end portions 111c and 112c of the narrowed portions 111 and 112. In this case, in the depth direction Z, the mold downstream inclined surface 472 of the mold downstream surface 55d is provided between the tops 111a and 112a of the narrowed portions 111 and 112 and the downstream ends 111c and 112c. In the aligned cross-section CS41, the separation distance W42a between the mold downstream inclined surface 472 and the front downstream end portion 111c of the front narrowed portion 111 in the depth direction Z is equal to the mold downstream inclined surface 472 and the back downstream end portion 112c of the back narrowed portion 112. It is the same as the separation distance W42b from. The separation distance W42a is smaller than the length dimension W33a of the front expansion surface 432, and the separation distance W42b is smaller than the length dimension W33b of the back expansion surface 442.

A portion of the sensor support portion 51, which is arranged on the aligned section CS41 of the mold upstream inclined surface 471, is located at a position aligned with the guide measurement path 352 in the height direction Y. This portion is provided on the upstream curved path 406 on the downstream side of the housing with respect to the upstream inner curved surface 415. In the measurement flow path 32, the guide measurement path 352 may be referred to as a first section, the detection measurement path 353 may be referred to as a second section, and the discharge measurement path 354 may be referred to as a third section. The discharge measurement path 354 has a portion that extends straight in the height direction Y and a portion that extends from the measurement outlet 36 in a direction inclined in the height direction Y.

The flow rate sensor 22 is arranged according to the position where the flow velocity of the air flowing through the measurement flow channel 32 is maximized. Specifically, the flow rate sensor 22 is provided at a position where the flow velocity of air is the highest. In the present embodiment, the position where the flow velocity of air is the highest in the measurement flow path 32 is the position where the front top 111a is provided, and the flow rate sensor 22 is provided at the position facing the front top 111a.

According to the present embodiment described up to this point, since the measurement flow passage 32 is provided with the throttle portion 111, the air flowing through the measurement flow passage 32 can be rectified. Moreover, in the aligned section CS41, the mold upstream surface 55c of the sensor support portion 51 is provided on the upstream side of the throttle portions 111 and 112. In this configuration, the air that has passed through the mold upstream surface 55c along the aligned section CS41 is rectified by the entire throttle portions 111 and 112 in the aligned section CS41. In this case, even if turbulence of the air flow occurs due to the air flowing through the measurement flow path 32 reaching the sensor support portion 51, this turbulence of the air flow can be reduced in the entire throttle portions 111 and 112. That is, it is unlikely that the rectification effect of the throttle portions 111 and 112 is reduced by the presence of the sensor support portion 51. For this reason, it is possible to suppress a decrease in the flow rate detection accuracy of the flow rate sensor 22, and as a result, it is possible to improve the flow rate measurement accuracy of the air flow meter 20.

According to this embodiment, the mold upstream inclined surface 471 is arranged at a position straddling the upstream end portions 111b and 112b of the narrowed portions 111 and 112 in the depth direction Z. With this configuration, it is not necessary to arrange the entire mold upstream inclined surface 471 and the entire mold upstream surface 55c on the upstream side of the throttle portions 111 and 112 in the measurement flow path 32, and therefore, the sensor support portion 51 and the mold portion. 55 can be miniaturized. Therefore, it is possible to prevent the air flow in the measurement flow channel 32 from being disturbed due to the increase in size of the sensor support portion 51 on the upstream side.

Further, a configuration in which the cross-sectional area S4 of the measurement flow channel 32 is reduced from the measurement inlet 35 side toward the flow rate sensor 22 is referred to as a configuration in which the measurement flow channel 32 is narrowed, together with the throttle surfaces 431 and 441, the sensor support portion 51. Will also be included in the configuration of narrowing the measurement flow path 32. For this reason, since the mold upstream inclined surface 471 is provided at a position straddling the upstream end portions 111b and 112b of the narrowed portions 111 and 112 in the depth direction Z, the sensor support portion 51 and the narrowed portions 111 and 112 can be measured. The passage 32 can be continuously throttled toward the flow sensor 22. As a result, the cross-sectional area S4 of the measurement flow path 32 increases or decreases from the measurement inlet 35 side toward the flow rate sensor 22, and the rectification effect by the sensor support portion 51 and the throttle portions 111 and 112 is reduced. Can be suppressed.

On the other hand, for example, in the configuration in which the sensor support portion 51 and the throttle portions 111 and 112 are provided at positions separated from each other in the direction in which the measurement flow path 32 extends, for example, the sensor support portion 51 and the throttle portions 111 and 112. And the cross-sectional area S4 of the flow rate sensor 22 increases. In other words, the sensor support portion 51 and the throttle portions 111 and 112 cannot continuously throttle the measurement flow path 32 toward the flow rate sensor 22. In this case, the cross-sectional area S4 of the measurement flow path 32 increases or decreases from the measurement inlet 35 side toward the flow rate sensor 22, and the rectification effect by the sensor support portion 51 and the throttle portions 111 and 112 is reduced. Is concerned.

Moreover, in the configuration in which the mold upstream inclined surface 471 is provided at a position that straddles the upstream end portions 111b and 112b of the throttle portions 111 and 112 in the depth direction Z, the volume of the sensor support portion 51 in the measurement flow channel 32 is equal to the measurement inlet 35. It gradually increases from the side toward the flow sensor 22. In this case, the sensor support portion 51 can gradually narrow the measurement flow passage 32 by gradually reducing the cross-sectional area S4 of the measurement flow passage 32 from the measurement inlet 35 side toward the flow rate sensor 22. Therefore, it is possible to prevent the degree of throttling by the sensor support portion 51 from being too steep and causing turbulence of the air flow in the measurement flow channel 32.

According to the present embodiment, in the aligned section CS41, the mold downstream surface 55d of the sensor support portion 51 is provided on the upstream side of the downstream end portions 111c and 112c of the throttle portions 111 and 112. With this configuration, the turbulence of the air passing through the downstream end portions 111c and 112c of the sensor support portion 51 can be suppressed by the rectifying effect of the throttle portions 111 and 112. The rectifying effect of the throttle portions 111 and 112 is exerted by the expansion surfaces 432 and 442 even on the downstream side of the top portions 111a and 112a. Moreover, in this configuration, for example, the sensor support portion 51 can be made smaller than a configuration in which the mold downstream surface 55d is arranged on the downstream side of the throttle portions 111 and 112 in the aligned cross section CS41. As a result, it is difficult for the rectifying effect of the throttle portions 111 and 112 to decrease due to the increase in size of the sensor support portion 51.

According to the present embodiment, the mold downstream inclined surface 472 is arranged at a position straddling the downstream end portions 111c and 112c of the narrowed portions 111 and 112 in the depth direction Z. In this configuration, it is not necessary to arrange the entire mold downstream inclined surface 472 and the entire mold downstream surface 55d on the upstream side of the downstream end portions 111c and 112c of the throttle portions 111 and 112 in the measurement flow channel 32. The sensor support portion 51 and the mold portion 55 can be downsized. Therefore, it is possible to prevent the air flow in the measurement flow path 32 from being disturbed due to the size increase of the sensor support portion 51 on the downstream side.

Further, when a configuration in which the cross-sectional area S4 of the measurement flow channel 32 is increased from the flow rate sensor 22 toward the measurement outlet 36 is referred to as a configuration for expanding the measurement flow channel 32, the sensor support portion 51 together with the extension surfaces 432 and 442 is called. Will also be included in the configuration for expanding the measurement channel 32. For this reason, since the mold downstream inclined surface 472 is provided at a position straddling the downstream end portions 111c and 112c of the narrowed portions 111 and 112 in the depth direction Z, the sensor support portion 51 and the narrowed portions 111 and 112 are measured. The passage 32 can be continuously expanded towards the measuring outlet 36. As a result, the cross-sectional area S4 of the measurement flow path 32 increases or decreases from the flow rate sensor 22 toward the measurement outlet 36, and the rectification effect of the sensor support portion 51 and the throttle portions 111 and 112 decreases. Can be suppressed.

According to the present embodiment, in the narrowed portions 111, 112 provided on the downstream side of the mold front end surface 55a of the sensor support portion 51 in the aligned cross section CS41, the length dimensions W33a, W33b of the expanded surfaces 432, 442 are the narrowed surfaces. It is larger than the length dimension W32a of 431,441. With this configuration, the flow of measurement that has passed through the mold tip surface 55a and reached the throttles 111 and 112 is measured so that turbulence such as separation does not occur due to rapid expansion of the measurement flow channel 32 by the throttles 111 and 112. The passage 32 is gently expanded towards the measuring outlet 36. Therefore, it is possible to suppress the turbulence of the airflow that has passed through the sensor support portion 51 and the throttle portions 111 and 112.

According to the present embodiment, the front throttle portion 111 is provided on the front measurement wall surface 103 at a position facing the flow rate sensor 22. Therefore, in the arrangement cross section CS41, the mold upstream surface 55c is arranged on the upstream side of the front throttle portion 111 to enhance the rectification effect of the front throttle portion 111, and the air flowing along the flow rate sensor 22 is made to flow through the front throttle portion 111. By this, it is possible to rectify more effectively.

According to this embodiment, the back throttle 112 is provided on the opposite side of the front throttle 111 with the flow sensor 22 interposed therebetween. Therefore, in the arrangement in which the mold upstream surface 55c is arranged on the upstream side of the front throttle portion 111 in the aligned section CS41 to enhance the rectification effect of the front throttle portion 111, the space between the sensor support portion 51 and the back measurement wall surface 104 is increased. The flowing air can also be rectified by the back throttle 112. Therefore, it can be suppressed that the air flowing along the flow rate sensor 22 is disturbed and the detection accuracy of the flow rate sensor 22 is lowered due to the air flow flowing between the sensor support portion 51 and the back measurement wall surface 104 being disturbed.

According to the present embodiment, the sensor support portion 51 is provided at a position closer to the front diaphragm portion 111 than the back diaphragm portion 112 in the width direction X. Therefore, in a configuration in which the mold upstream surface 55c is arranged on the upstream side of the front throttle portion 111 in the aligned cross section CS41 to enhance the rectification effect of the front throttle portion 111, a table intended for air flowing along the flow rate sensor 22. The rectification effect of the throttle unit 111 can be further enhanced.

According to this embodiment, the reduction ratio of the measurement flow channel 32 by the front narrowing unit 111 is larger than the reduction ratio of the measurement flow channel 32 by the back narrowing unit 112. Therefore, in a configuration in which the mold upstream surface 55c is arranged on the upstream side of the front narrowing portion 111 in the aligned section CS41 to enhance the straightening effect of the front narrowing portion 111, the straightening effect of the front narrowing portion 111 is reduced by the back narrowing portion 112. It can be enhanced more than the rectification effect. Moreover, foreign matter such as dust contained in the air flowing toward the flow rate sensor 22 is more likely to enter between the sensor support portion 51 and the back throttle portion 112 than between the sensor support portion 51 and the front throttle portion 111. A configuration can be realized.

According to the present embodiment, the flow rate sensor 22 is arranged at the position where the flow velocity is highest in the measurement flow channel 32. Therefore, in the arrangement cross section CS41, the mold upstream surface 55c is arranged on the upstream side of the front throttle portion 111 to enhance the rectifying effect of the front throttle portion 111, and the amount and speed of the air flowing along the flow rate sensor 22 are It is possible to suppress the shortage.

According to this embodiment, the portion of the mold upstream surface 55c of the sensor support portion 51 that is arranged in the aligned cross section CS41 is included in the upstream curved path 406. Therefore, in a configuration in which the mold upstream surface 55c is arranged on the upstream side of the front throttle portion 111 in the aligned cross section CS41 to enhance the rectification effect of the front throttle portion 111, it is assumed that the turbulence of the air flow occurs in the upstream curved path 406. However, this turbulence can be reduced by the diaphragm portions 111 and 112.

According to this embodiment, the opening area of the measurement outlet 36 is smaller than the opening area of the measurement inlet 35. Since the measurement outlet 36 is narrower than the measurement inlet 35 in this way, it is possible to realize a configuration in which the entire measurement flow path 32 is narrowed toward the measurement outlet 36. Therefore, in a configuration in which the mold upstream surface 55c is arranged on the upstream side of the front narrowing portion 111 in the aligned cross section CS41 and the straightening effect of the front narrowing portion 111 is enhanced, the straightening effect is further enhanced in the entire measurement flow channel 32. You can

According to this embodiment, the opening area of the passage outlet 34 is smaller than the opening area of the passage inlet 33. As described above, since the passage outlet 34 is narrower than the passage inlet 33, it is possible to realize a configuration in which the entire passage passage 31 is narrowed toward the measurement inlet 35 and the passage outlet 34. Therefore, in a configuration in which the mold upstream surface 55c is arranged on the upstream side of the front narrowing portion 111 in the aligned cross section CS41 to enhance the straightening effect of the front narrowing portion 111, the straightening effect is further enhanced in the entire passage passage 31. You can

<Explanation of configuration group H>
As shown in FIG. 3, the housing 21 has flange holes 611 and 612. The flange holes 611 and 612 are provided in the flange portion 27 and are through holes that penetrate the flange portion 27 in the height direction Y. The flange holes 611 and 612 are provided at positions separated from each other in the width direction X and the depth direction Z, respectively. The passage 31 is arranged between the flange holes 611 and 612 in the width direction X. Of the flange holes 611 and 612, the first flange hole 611 is provided between the connector portion 28 and the passage channel 31 in the width direction X, and the second flange hole 612 is the passage channel in the width direction X. It is provided on the opposite side of the first flange hole 611 through the hole 31.

Assuming a flange hole line CL61 as a straight virtual line passing through the center CO61 of the first flange hole 611 and the center CO62 of the second flange hole 612, this flange hole line CL61 overlaps with the passage inlet 33 of the passage passage 31. To do. In other words, the passage inlet 33 is provided between the first flange hole 611 and the second flange hole 612 in a plan view when the air flow meter 20 is viewed from the housing base end side. The center line of the screw inserted into the flange holes 611 and 612 extends in the height direction Y and passes through the centers CO61 and CO62 of the flange holes 611 and 612.

When the housing 21 is fixed to the tube boss 14d with a screw, the center line of the screw may be displaced from the center CO61, CO62 of the flange hole 611, 612 due to the position shift of the screw with respect to the flange hole 611, 612. is assumed. In this case, the housing 21 is displaced in the width direction X and the depth direction Z around the screw as an axis, but the portion of the housing 21 that overlaps the flange hole line CL61 in a plan view is compared to other portions. It is difficult for the position to shift in the width direction X and the depth direction Z. As described above, since a part of the passage inlet 33 overlaps the flange hole line CL61 in a plan view, the displacement of the passage inlet 33 in the intake passage 12 is unlikely to occur. Therefore, a product error is less likely to occur in the position of the passage inlet 33 in the intake passage 12, and it is possible to suppress that the easiness of the air flowing into the passage inlet 33 in the intake passage 12 varies depending on the product. Thereby, the accuracy of measuring the flow rate by the air flow meter 20 can be improved.

The passage inlet 33 is preferably arranged at the center of the intake passage 12 or at a position close to the center in the directions X and Y orthogonal to the depth direction Z. This is because the center of the intake passage 12 is the position where the flow rate and the flow velocity are most likely to be the largest and the air flow is most likely to be stable.

No metal bush is provided in the flange holes 611 and 612. With this configuration, the screw is likely to directly contact the portion of the flange portion 27 where the flange holes 611 and 612 are formed. The flange holes 611 and 612 may be provided with metal bushes. In this configuration, the screw is more likely to contact the bush than the portion of the flange portion 27 where the flange holes 611 and 612 are formed.

As shown in FIG. 28, the housing 21 has a connector guide portion 613. The connector guide portion 613 is provided on the outer surface of the connector portion 28 and extends in the opening direction of the connector portion 28. The connector guide portion 613 is a portion that guides the position of the plug portion with respect to the connector portion 28 when the plug portion is mounted on the connector portion 28, and also guides the inserting direction of the plug portion. The connector guide portion 613 is provided, for example, in a portion of the connector portion 28 that forms the housing base end surface 21b, and is a portion of the housing 21 that projects most toward the housing base end side.

The angle setting surface 27a of the flange portion 27 is provided closer to the housing base end side than the mold portion 55 of the sensor SA50 in the height direction Y. With this configuration, even if the flange portion 27 is deformed due to the angle setting surface 27a being caught by the pipe boss 14d, it is unlikely that the position of the mold portion 55 is unintentionally changed due to this deformation. Has become. Therefore, it is possible to prevent the flow sensor 22 in the measurement flow channel 32 from changing unintentionally.

The connector terminal 28a of the connector portion 28 is provided closer to the housing base end side than the mold portion 55 of the sensor SA50 in the height direction Y. With this configuration, even if the connector terminal 28a is deformed due to the plug terminal being connected to the connector terminal 28a when the plug portion is mounted on the connector portion 28, the deformation allows the position of the mold portion 55 to be intended. It is hard to change without changing.

The connector terminal 28a is provided closer to the housing base end side than the angle setting surface 27a in the height direction Y. In this case, the distance H62 between the connector terminal 28a and the mold portion 55 in the height direction Y is larger than the distance H61 between the angle setting surface 27a and the mold portion 55 in the height direction Y. The connector terminal 28a may not be provided on the housing proximal end side with respect to the angle setting surface 27a.

The holding groove portion 25 a of the seal holding portion 25 is provided closer to the housing base end side than the housing partition portion 131 of the housing 21. In this configuration, even if the holding groove 25a is deformed due to the sealing member 26 being in close contact with both the inner surface of the holding groove 25a and the inner surface of the pipe flange 14c, the housing partition 131 is intended to be deformed by this deformation. It is less likely to deform without doing it. Therefore, it is possible to prevent the state in which the housing partition portion 131 partitions the SA accommodation area 150 and the measurement flow path 32 from being unintentionally released.

The housing 21 has a tip protection protrusion 615, an upstream protection protrusion 616, and a downstream protection protrusion 617. All of these protective convex portions 615 to 617 are convex portions provided on the housing back surface 21f. The tip protection protrusion 615 is provided closer to the housing tip side than the intake air temperature sensor 23 in the height direction Y, and does not project to the housing back side from the intake air temperature sensor 23 in the width direction X. The upstream protection convex portion 616 is provided on the upstream side of the housing with respect to the intake air temperature sensor 23 in the depth direction Z. The downstream protection convex portion 617 is provided on the housing downstream side of the intake air temperature sensor 23 in the depth direction Z. The upstream protection protrusion 616 and the downstream protection protrusion 617 protrude toward the back side of the housing in the width direction X from the intake air temperature sensor 23, and are provided closer to the housing base end side than the intake air temperature sensor 23 in the height direction Y. ..

In the height direction Y, the distance H63 between the holding groove 25a and the housing partition 131 is larger than the distance H64 between the end of the tip protection protrusion 615 on the front end side of the housing and the intake air temperature sensor 23. Further, the separation distance H63 is larger than any of the separation distances H61, H62, and H64.

A connection terminal 620 having a connector terminal 28a is attached to the housing 21. As shown in FIGS. 29 and 30, the connection terminal 620 has a lead connection terminal 621, an intake air temperature connection terminal 622, and an adjustment connection terminal 623 in addition to the connector terminal 28a. A plurality of lead connection terminals 621 are provided on the connection terminal 620 and extend in the height direction Y. The lead connection terminals 621 include a terminal connected to the connector terminal 28a, a terminal connected to the intake air temperature connection terminal 622, and a terminal connected to the adjustment connection terminal 623.

The connector terminal 28a, the intake air temperature connection terminal 622, and the adjustment connection terminal 623 extend from the lead connection terminal 621 in the directions X and Z orthogonal to the height direction Y. The intake air temperature connection terminal 622 is a terminal electrically connected to the lead wire 23 a of the intake air temperature sensor 23. The intake air temperature connection terminal 622 has a free end bent, and extends in the height direction Y similarly to the lead connection terminal 621. The direction in which the bent end portion of the intake air temperature connection terminal 622 extends is the same as the direction in which the lead connection terminal 621 extends. Therefore, the intake temperature connection terminal 622 and the lead connection terminal 621 can be formed by simply bending the base material of the connection terminal 620 in the same direction. The adjustment connection terminal 623 is a terminal for adjusting the output signal from the connector terminal 28a when the air flow meter 20 is manufactured.

The connector terminal 28a has a connector base portion 625 and a connector connecting portion 626. The connector base portion 625 is a portion of the connector terminal 28a extending from the lead connection terminal 621, and forms a base end portion of the connector terminal 28a. The connector connecting portion 626 is a portion of the connector terminal 28a extending from the connector base portion 625, and forms a tip portion of the connector terminal 28a. The connector base portion 625 and the connector connecting portion 626 have the same thickness dimension in the height direction Y, while the connector base portion 625 has a width dimension in the depth direction Z larger than that of the connector connecting portion 626. ing. That is, the connector base portion 625 is thicker than the connector connecting portion 626.

In this embodiment, three connector terminals 28a are provided, and these connector terminals 28a are arranged in the depth direction Z in parallel with each other. Among the three connector terminals 28a, in the connector terminal 28a arranged in the middle, the connector connecting portion 626 extends from the central position of the connector base portion 625 in the depth direction Z. In the connector terminal 28a arranged at one end, the connector connecting portion 626 extends from the end of the connector base portion 625 farther from the adjacent connector terminal 28a. In this connector terminal 28a, the connector base portion 625 is in a state of protruding from the connector connecting portion 626 toward the adjacent connector terminal 28a side. Also in the connector terminal 28a arranged at the other end, the connector connecting portion 626 extends from the end of the connector base portion 625 farther from the adjacent connector terminal 28a.

In the connection terminal 620, the width dimension in the depth direction Z is defined by the intake air temperature connection terminal 622. The connection terminal 620 has two intake air temperature connection terminals 622, and these connection terminals 620 are arranged in the depth direction Z. The connection terminal 620 has six lead connection terminals 621, and these lead connection terminals 621 are arranged in the depth direction Z. The intake air temperature connection terminal 622 and the lead connection terminal 621 are arranged in the width direction X, and the width dimension of the region where the two connection terminals 620 are installed in the depth direction Z is such that the six lead connection terminals 621 are installed. It is larger than the width of the area. In this case, in the depth direction Z, the area in which the six lead connection terminals 621 are installed is smaller than the area in which the two connection terminals 620 are installed, and does not protrude.

As shown in FIG. 32, the inner surface of the housing 21 has a front passage wall surface 631 and a back passage wall surface 632 in addition to the passage ceiling surface 341 and the passage floor surface 345 as formation surfaces forming the passage passage 31. There is. The front passage wall surface 631 and the back passage wall surface 632 are a pair of wall surfaces that face each other via the passage ceiling surface 341 and the passage floor surface 345, and are extended over the passage ceiling surface 341 and the passage floor surface 345. The front passage wall surface 631 extends from the front measurement wall surface 103 toward the housing front end side, and the back passage wall surface 632 extends from the back measurement wall surface 104 toward the housing front end side.

The inner surface of the housing 21 has a front passage diaphragm surface 635 and a back passage diaphragm surface 636. The front passage diaphragm surface 635 is included in the front passage wall surface 631, and the back passage diaphragm surface 636 is included in the back passage wall surface 632. These passage restricting surfaces 635 and 636 gradually narrow the passage passage 31 so that the cross-sectional area of the passage passage 31 gradually decreases from the passage inlet 33 side toward the passage outlet 34. The passage restricting surfaces 635 and 636 are provided in the passage passage 31 between the measurement inlet 35 and the passage outlet 34. The passage restricting surfaces 635 and 636 are spanned by the outlet ceiling surface 343 and the passage floor surface 345, and measure the distance between the front passage wall surface 631 and the back passage wall surface 632 in the width direction X from the measurement inlet 35 to the passage outlet 34. Gradually decreasing toward. The passage restricting surfaces 635 and 636 are inclined with respect to the depth direction Z, which is the direction in which the center line of the passage passage 31 extends, and all face the passage inlet 33 side.

The inner surface of the housing 21 has a front diaphragm top 637 and a back diaphragm top 638. The front diaphragm top portion 637 is included in the front passage wall surface 631 and is a surface that extends over the front passage diaphragm surface 635 and the passage outlet 34. The back diaphragm top portion 638 is included in the back passage wall surface 632, and is a surface spanned by the back passage diaphragm surface 636 and the passage exit 34. The throttle tops 637 and 638 extend in the depth direction Z in parallel with the center line of the passage 31 and face each other.

As shown in FIG. 32, the housing 21 has a housing outer wall 651. The housing outer wall 651 forms the outer surface of the housing 21, and is a cylindrical portion extending in the height direction Y. The outer surface of the housing outer wall 651 forms a housing upstream surface 21c, a housing downstream surface 21d, a housing front surface 21e, and a housing back surface 21f. The housing front surface 21e and the housing rear surface 21f include a flat surface that extends straight in the depth direction Z and an inclined surface that is inclined with respect to the flat surface so as to face the housing upstream side. The measurement outlet 36 is provided at a position across the boundary between the flat surface and the inclined surface in the depth direction Z on each of the housing front surface 21e and the housing back surface 21f.

A measurement hole portion 652 is provided on the housing outer wall 651. The measurement hole portion 652 is provided on each of the housing front surface 21e and the housing back surface 21f, and the outer ends of these measurement hole portions 652 form the measurement outlets 36, respectively. The measurement hole portion 652 extends in the width direction X from the measurement outlet 36. The measurement hole portion 652 provided on the front surface side of the housing is spanned between the measurement outlet 36 provided on the housing surface 21e and the front measurement wall surface 103. The measurement hole portion 652 provided on the back side of the housing is spanned between the measurement outlet 36 provided on the rear surface 21f of the housing and the back measurement wall surface 104.

The inner surface of the measurement hole portion 652 has an upstream forming surface 661 and a downstream forming surface 662. The upstream forming surface 661 forms the end of the measurement hole 652 on the upstream side of the housing, and faces the downstream side of the housing. The downstream forming surface 662 forms the end of the measurement hole 652 on the downstream side of the housing, and faces the upstream side of the housing. The upstream forming surface 661 and the downstream forming surface 662 extend across the measurement outlet 36 and the measurement wall surfaces 103 and 104 in the width direction X.

The downstream forming surface 662 has a downstream inclined surface 662a and a downstream facing surface 662b. The downstream inclined surface 662a extends in a direction inclined with respect to the width direction X, and extends in the height direction Y in a state of facing obliquely outward. The downstream facing surface 662b extends in the width direction X and faces the upstream forming surface 661 in parallel. The width dimension of the downstream inclined surface 662a in the width direction X is smaller than the width dimension of the upstream formation surface 661 in the width direction X. On the other hand, the width dimension of the downstream inclined surface 662a in the width direction X is larger than the width dimension of the downstream facing surface 662b in the width direction X.

In the measurement hole portion 652, since the downstream inclined surface 662a of the downstream forming surface 662 faces obliquely outside, the air flowing out from the measurement outlet 36 is directed toward the housing downstream side along the downstream inclined surface 662a in the measurement flow path 32. It will proceed diagonally. In this case, the air flowing out from the measurement outlet 36 is inclined with respect to the width direction X and advances toward the housing downstream side, so that the air easily flows into the intake passage 12 in the mainstream direction. Therefore, for example, as compared with the case where the air flows out from the measurement outlet 36 in the width direction X, the turbulence of the airflow is less likely to occur around the measurement outlet 36.

(Second embodiment)
In the first embodiment, the housing opening 151a communicating with the SA accommodation area 150 is provided on the housing proximal end side of the first housing 151. On the other hand, in the second embodiment, the base opening 291a communicating with the SA accommodation area 290 is provided on the front surface side of the housing of the base member 291. In the present embodiment, an air flow meter 200 is included in the combustion system 10 as a physical quantity measuring device instead of the air flow meter 20. In the present embodiment, the components denoted by the same reference numerals as those in the drawings in the first embodiment and the configuration not described are the same as those in the first embodiment, and have the same operational effects. In this embodiment, differences from the first embodiment will be mainly described.

As shown in FIGS. 33 and 34, the air flow meter 200 is provided in the intake passage 12. The air flow meter 200 is a physical quantity measuring device that measures a physical quantity, like the air flow meter 20 of the first embodiment, and is attached to the piping unit 14 (see FIGS. 2 and 8).

The air flow meter 200 has an entry portion 200a that has entered the intake passage 12, and an extension portion 200b that has protruded outside from the pipe flange 14c without entering the intake passage 12. The entering portion 200a and the protruding portion 200b are aligned in the height direction Y.

The air flow meter 200 has a housing 201 and a flow rate sensor 202 that detects the flow rate of intake air. The housing 201 is made of, for example, a resin material. The flow rate sensor 202 is housed inside the housing 201. In the air flow meter 200, since the housing 201 is attached to the intake pipe 14a, the flow rate sensor 202 can come into contact with the intake air flowing through the intake passage 12.

The housing 21 is attached to the piping unit 14 as an attachment target. On the outer surface of the housing 201, of the pair of end surfaces 201a and 201b arranged in the height direction Y, the one included in the entering portion 200a is referred to as a housing front end surface 201a, and the one included in the protruding portion 200b is the housing base. It is referred to as the end surface 201b. The housing front end surface 201a and the housing base end surface 201b are orthogonal to the height direction Y.

On the outer surface of the housing 201, a surface arranged on the upstream side of the intake passage 12 is referred to as a housing upstream surface 201c, and a surface arranged on the opposite side of the housing upstream surface 201c is referred to as a housing downstream surface 201d. Further, one of a pair of surfaces facing each other through the housing upstream surface 201c and the housing base end surface 201b is referred to as a housing front surface 201e, and the other is referred to as a housing back surface 201f. The housing surface 201e is a surface of the sensor SA220, which will be described later, on which the flow rate sensor 202 is provided.

Regarding the housing 201, in the height direction Y, the housing front end surface 201a side is referred to as the housing front end side, and the housing base end surface 201b side is referred to as the housing base end side. Further, in the depth direction Z, the housing upstream surface 201c side is referred to as the housing upstream side, and the housing downstream surface 201d side is referred to as the housing downstream side. Further, in the width direction X, the housing front surface 201e side is referred to as the housing front side, and the housing back surface 201f is referred to as the housing back side.

As shown in FIGS. 33, 34, and 35, the housing 201 has a seal holding portion 205, a flange portion 207, and a connector portion 208. The air flow meter 200 has a seal member 206, and the seal member 206 is attached to the seal holder 25.

The seal holding portion 205 is provided inside the pipe flange 14c and holds the seal member 206 so as not to be displaced in the height direction Y. The seal holder 205 is included in the entry portion 200a of the air flow meter 200. The seal member 206 is a member such as an O-ring that seals the intake passage 12 inside the pipe flange 14c, and is in close contact with both the outer peripheral surface of the seal holding portion 205 and the inner peripheral surface of the pipe flange 14c. The connector unit 208 is a protection unit that protects the connector terminal 208a electrically connected to the flow rate sensor 202. The connector terminal 208a is electrically connected to the ECU 15 by connecting the electrical wiring extending from the ECU 15 to the connector portion 208 via the plug portion. For example, the connector terminal 208a is electrically and mechanically connected to the plug terminal of the plug portion. The flange portion 207 and the connector portion 208 are included in the protruding portion 200b of the air flow meter 200.

The housing 201 has a bypass flow path 210. The bypass channel 210 is provided inside the housing 201 and is formed by at least a part of the internal space of the housing 201. The inner surface of the housing 201 forms a bypass flow path 210, which is a forming surface.

The bypass flow passage 210 is arranged in the entry portion 200a of the air flow meter 200. The bypass flow passage 210 has a passage flow passage 211 and a measurement flow passage 212. The measurement flow path 212 is in a state in which the flow rate sensor 202 of the sensor SA 220, which will be described later, and a portion around the flow rate sensor 202 enter. The passage 211 is formed by the inner surface of the housing 201. The measurement flow path 212 is formed by the outer surface of a part of the sensor SA 220 in addition to the inner surface of the housing 201. The intake passage 12 may be referred to as a main passage and the bypass passage 210 may be referred to as a sub passage.

The passage channel 211 penetrates the housing 201 in the depth direction Z. The passage channel 211 has a passage inlet 213 which is an upstream end thereof and a passage outlet 214 which is a downstream end thereof. The measurement flow path 212 is a branch flow path branched from an intermediate portion of the passage flow path 211, and the measurement flow path 212 is provided with the flow rate sensor 202. The measurement flow path 212 has a measurement inlet 215 that is an upstream end thereof and a measurement outlet 216 that is a downstream end thereof. A portion where the measurement flow path 212 branches from the passage flow path 211 is a boundary portion between the passage flow path 211 and the measurement flow path 212, and the measurement inlet 215 is included in this boundary portion. Further, the boundary portion between the passage channel 211 and the measurement channel 212 can also be referred to as a channel boundary portion.

The measurement flow path 212 extends from the passage flow path 211 toward the housing base end side. The measurement flow path 212 is provided between the passage flow path 211 and the housing base end surface 201b. The measurement flow path 212 is curved so that the portion between the measurement inlet 215 and the measurement outlet 216 bulges toward the base end side of the housing. The measurement flow path 212 has a portion which is curved so as to be bent continuously, a portion which is bent so as to be bent in a stepwise manner, and a portion which extends straight in the height direction Y and the depth direction Z.

The air flow meter 200 has a sensor subassembly including a flow rate sensor 202, and this sensor subassembly is referred to as a sensor SA220. The sensor SA220 is embedded in the housing 201 in a state where a part of the sensor SA220 enters the measurement flow channel 212. In the air flow meter 200, the sensor SA 220 and the bypass flow passage 210 are arranged in the height direction Y. Specifically, the sensor SA220 and the passage channel 211 are arranged in the height direction. The sensor SA220 corresponds to the detection unit. Further, the sensor SA220 can also be referred to as a measurement unit or a sensor package.

The housing 201 has an upstream wall portion 231, a downstream wall portion 232, a front wall portion 233, a back wall portion 234, and a front end wall portion 235. The upstream wall portion 231 forms the housing upstream surface 201c, and the downstream wall portion 232 forms the housing downstream surface 201d. The front wall portion 233 forms the housing front surface 201e, and the back wall portion 234 forms the housing back surface 201f. The upstream wall portion 231 and the downstream wall portion 232 are provided at positions separated from each other in the depth direction Z, and the front wall portion 233 and the back wall portion 234 are provided at positions separated from each other in the width direction X. The measurement flow path 212 and the SA accommodation area 290 described later are provided between the upstream wall portion 231 and the downstream wall portion 232, and between the front wall portion 233 and the back wall portion 234. The front end wall portion 235 forms the front end surface 201a of the housing, and is provided at a position apart from the seal holding portion 205 in the height direction Y.

The housing 201 has a first intermediate wall portion 236 and a second intermediate wall portion 237. The intermediate wall portions 236 and 237 extend in a plate shape in the directions X and Z orthogonal to the height direction Y, similarly to the tip wall portion 235, and in the height direction Y, the tip wall portion 235 and the seal holding portion 205. It is provided in between. The first intermediate wall portion 236 is provided between the distal end wall portion 235 and the second intermediate wall portion 237, and the bypass flow path 210 is provided between the first intermediate wall portion 236 and the distal end wall portion 235. Has been. The first intermediate wall portion 236 is provided between the measurement flow path 32 and the SA accommodation area 290, and partitions the measurement flow path 212 and the SA accommodation area 290 in the height direction Y. The second intermediate wall portion 237 is provided between the first intermediate wall portion 236 and the seal holding portion 205, and partitions the SA accommodation area 290 in the height direction Y.

The first intermediate wall portion 236 is provided with a first intermediate hole 236a. The first intermediate hole 236a penetrates the first intermediate wall portion 236 in the height direction Y. The inner peripheral surface of the first intermediate wall portion 236 is included in the inner surface of the housing 201, and extends annularly along the peripheral edge portion of the first intermediate hole 236a. In the sensor SA220, the portion on the flow sensor 202 side penetrates the first intermediate hole 236a in the height direction Y. As a result, in the sensor SA220, the mold front end surface 225a and the flow rate sensor 202 are installed in the measurement flow path 32, and the mold base end surface 225b is installed in the SA accommodation area 290.

The second intermediate wall portion 237 is provided with a second intermediate hole 237a. The second intermediate hole 237a passes through the second intermediate wall portion 237 in the height direction Y. In the sensor SA220, a lead terminal 53a described later penetrates the second intermediate hole 237a in the height direction Y. As a result, in the sensor SA220, the mold portion 225 described later is arranged closer to the housing front end side than the second intermediate wall portion 237, and at least the distal end portion of the lead terminal 53a is closer to the housing base end side than the second intermediate wall portion 237. It is arranged.

In the SA accommodation area 290, a filling portion (not shown) is filled in the gap between the housing 201 and the sensor SA220. The filling part is formed of a thermosetting resin such as an epoxy resin, a urethane resin, or a silicone resin. Here, the filling portion is formed by filling the SA accommodation area 290 with the molten resin in a state where the thermosetting resin is melted by potting and solidifying the molten resin as the potting resin. The filling part can also be called a potting part or a potting resin part.

<Explanation of configuration group A>
The sensor SA220 has a sensor support portion 221 in addition to the flow rate sensor 202. The sensor support portion 221 is attached to the housing 201 and supports the flow rate sensor 202. The sensor support part 221 has an SA substrate 223 and a mold part 225. The SA substrate 223 is a substrate on which the flow sensor 202 is mounted, and the mold portion 225 covers at least a part of the flow sensor 202 and at least a part of the SA substrate 223. The SA substrate 223 can also be called a lead frame.

The mold part 225 is formed in a plate shape as a whole. In the mold portion 225, of the pair of end surfaces 225a and 225b arranged in the height direction Y, the housing front end side is referred to as the mold front end surface 225a, and the housing base end side is referred to as the mold base end surface 225b. The mold tip surface 225a is the tip of the mold portion 225 and the sensor support portion 221, and corresponds to the support tip portion. The mold part 225 corresponds to the protective resin part.

In the mold portion 225, one of a pair of surfaces provided with the mold front end surface 225a and the mold base end surface 225b sandwiched therebetween is referred to as a mold upstream surface 225c, and the other is referred to as a mold downstream surface 225d. The sensor SA220 is installed inside the housing 201 so that the mold front end surface 225a is arranged on the air flow front end side and the mold upstream surface 225c is arranged on the upstream side of the measurement flow path 212 with respect to the mold downstream surface 225d. There is.

The mold upstream surface 225c of the sensor SA220 is arranged on the upstream side of the mold downstream surface 225d in the measurement flow path 212. In the portion where the flow rate sensor 202 is provided in the measurement flow path 212, the direction of air flow is opposite to the direction of air flow in the intake passage 12 (see FIG. 8). Therefore, the mold upstream surface 225c is arranged on the downstream side of the mold downstream surface 225d in the intake passage 12. The air flowing along the flow rate sensor 202 flows in the depth direction Z, and this depth direction Z can also be referred to as a flow direction.

In the sensor SA220, the flow rate sensor 202 is exposed on one surface side of the sensor SA220. In the mold part 225, the plate surface on the side where the flow rate sensor 202 is exposed is referred to as a mold front surface 225e, and the plate surface on the opposite side is referred to as a mold back surface 225f. One plate surface of the sensor SA220 is formed by the mold surface 225e, the mold surface 225e corresponds to the support surface, and the mold back surface 225f corresponds to the support back surface.

The SA substrate 223 is formed of a metal material or the like in a plate shape as a whole, and is a conductive substrate. The plate surface of the SA substrate 223 is orthogonal to the width direction X and extends in the height direction Y and the depth direction Z. The flow rate sensor 202 is mounted on the SA substrate 223. The SA substrate 223 forms the lead terminal 223a connected to the connector terminal 208a. The SA substrate 223 has a portion covered by the mold portion 225 and a portion not covered by the mold portion 225, and the uncovered portion serves as the lead terminal 223a. The lead terminal 223a projects in the height direction Y from the mold base end surface 225b. 33 and 34, the lead terminal 223a is not shown.

The flow rate sensor 202 has the same configuration as the flow rate sensor 22 of the first embodiment. The flow rate sensor 202 includes, for example, the sensor recess 61 of the flow rate sensor 22, the membrane section 62, the sensor substrate 65, the sensor film section 66, the heating resistor 71, the temperature measuring resistors 72 and 73, the side heating resistor 74, and the wiring 75 to. It has parts and members corresponding to the respective 77.

<Explanation of Group B>
As shown in FIGS. 33 and 34, the housing 201 has an SA accommodation area 290. The SA accommodation area 290 is provided closer to the base end side of the housing than the bypass channel 210, and accommodates a part of the sensor SA220. At least the mold base end surface 225b of the sensor SA220 is housed in the SA housing area 290. The measurement flow path 212 and the SA accommodation area 290 are arranged in the height direction Y. The sensor SA220 is arranged at a position straddling the boundary portion between the measurement flow channel 212 and the SA accommodation area 290 in the height direction Y. At least the mold tip surface 225a of the sensor SA220 and the flow rate sensor 202 are housed in the measurement flow path 212. The SA accommodation area 290 corresponds to the accommodation area.

As shown in FIGS. 36 and 37, the housing 201 has a housing partition 271. The housing partition portion 271 is a convex portion provided on the inner peripheral surface of the first intermediate wall portion 236, and projects from the first intermediate wall portion 236 toward the sensor SA220. The tip of the housing partition 271 is in contact with the outer surface of the sensor SA220. The housing partition portion 271 partitions the SA accommodation area 290 and the measurement flow path 212 between the outer surface of the sensor SA 220 and the inner surface of the housing 201.

The inner surface of the housing 201 has a housing flow path surface 275, a housing housing surface 276, and a housing step surface 277. The housing flow path surface 275, the housing housing surface 276, and the housing step surface 277 extend in a direction intersecting the height direction Y, and make a circle around the sensor SA220. In the sensor SA220, the center line CL1a of the heating resistor extends linearly in the height direction Y as in the first embodiment, and the housing flow path surface 275, the housing accommodation surface 276, and the housing step surface 277 are respectively It extends around the center line in the circumferential direction.

The housing step surface 277 is a wall surface of the first intermediate wall portion 236 on the housing base end side, and faces the housing base end side in the height direction Y. The housing step surface 277 is inclined with respect to the center line CL1a and faces the inner side in the radial direction on the center line CL1a side. The housing step surface 277 intersects in the height direction Y and corresponds to a housing intersecting surface. In this embodiment, the housing step surface 277 is orthogonal to the center line CL1a. On the inner surface of the housing 201, the projecting corner portion of the housing flow passage surface 275 and the housing step surface 277 and the entering corner portion of the housing receiving surface 276 and the housing step surface 277 are chamfered.

The housing flow path surface 275 is an inner peripheral surface of the first intermediate wall portion 236. The housing flow path surface 275 forms the measurement flow path 212, and extends from the inner peripheral end of the housing step surface 277 toward the housing front end side. The housing flow path surface 275 extends from the housing step surface 277 toward the side opposite to the SA accommodation area 290.

On the other hand, the housing accommodation surface 276 is an inner surface of each of the upstream wall portion 231, the downstream wall portion 232, the front wall portion 233, and the back wall portion 234. The housing housing surface 276 forms an SA housing area 290, and extends from the outer peripheral end of the housing step surface 277 toward the housing base end side. The housing housing surface 276 extends from the housing step surface 277 toward the side opposite to the measurement flow path 212. The housing step surface 277 is provided between the housing flow path surface 275 and the housing housing surface 276, and forms a step on the inner surface of the housing 201. The housing step surface 277 connects the housing flow path surface 275 and the housing housing surface 276.

The outer surface of the sensor SA220 is formed by the outer surface of the mold portion 225. The outer surface of the sensor SA220 has an SA flow path surface 285, an SA housing surface 286, and an SA step surface 287. The SA flow path surface 285, the SA housing surface 286, and the SA step surface 287 extend in a direction intersecting with the height direction Y, and are a portion that makes a circle around the outer surface of the sensor SA220. The SA flow path surface 285, the SA housing surface 286, and the SA step surface 287 extend in the circumferential direction around the center line CL1a of the heating resistor.

In the sensor SA220, an SA step surface 287 is provided between the mold front end surface 225a and the mold base end surface 225b. The SA step surface 287 faces the mold front end surface 225a side in the height direction Y. The SA step surface 287 is inclined with respect to the center line CL1a and faces the radially outer side opposite to the center line CL1a. The SA step surface 287 intersects in the height direction Y and corresponds to a unit intersection surface. Further, the SA channel surface 285 corresponds to the unit channel surface, and the SA accommodation surface 286 corresponds to the unit accommodation surface. In this embodiment, the SA step surface 287 is orthogonal to the center line CL1a. On the outer surface of the sensor SA220, the corner portion of the SA flow path surface 285 and the SA step surface 287 and the corner portion of the SA housing surface 286 and the SA step surface 287 are chamfered.

The SA flow path surface 285 forms the measurement flow path 212, and extends in the height direction Y from the inner peripheral end of the SA step surface 287 toward the mold front end side. The SA flow path surface 285 extends from the SA step surface 287 toward the side opposite to the SA accommodation area 290. On the other hand, the SA housing surface 286 forms the SA housing area 290, and extends from the outer peripheral end of the SA step surface 287 toward the mold base end side. The SA accommodation surface 286 extends from the SA step surface 287 toward the side opposite to the measurement flow path 212. The SA step surface 287 is provided between the SA flow path surface 285 and the SA housing surface 286, and forms a step on the outer surface of the sensor SA220. The SA step surface 287 connects the SA flow path surface 285 and the SA housing surface 286.

In the sensor SA220, each of the SA flow path surface 285, the SA housing surface 286, and the SA step surface 287 is formed by the mold upstream surface 225c, the mold downstream surface 225d, the mold front surface 225e, and the mold back surface 225f.

In the air flow meter 200, the housing step surface 277 facing the housing base end side and the SA step surface 287 facing the housing front end side face each other. Further, the housing flow path surface 275 facing the inner peripheral side and the SA flow path surface 285 facing the outer peripheral side face each other. Similarly, the housing accommodation surface 276 facing the inner peripheral side and the SA accommodation surface 286 facing the outer peripheral side face each other.

The housing partition portion 271 of the present embodiment is not provided on the housing step surface 277 as in the first embodiment, but is provided on the housing flow path surface 275. In this case, the housing partition portion 271 extends toward the first intermediate hole 236a in the directions X and Zb intersecting the height direction Y. The center line CL12 of the housing partition portion 271 extends linearly in a direction intersecting the height direction Y. In this embodiment, the center line CL12 is orthogonal to the height direction Y. The housing partition portion 271 makes a loop around the sensor SA 220 together with the housing flow passage surface 275. In this case, the front end of the housing partition 271 forms the first intermediate hole 236a, and the front end surface of the housing partition 271 is the inner peripheral surface of the first intermediate hole 236a. Further, the housing partition portion 271 has a portion extending in the width direction X and a portion extending in the depth direction Z, and has a substantially rectangular frame shape as a whole.

The tip of the housing partition 271 is in contact with the SA flow path surface 285 of the sensor SA220. The housing partition 271 and the SA flow path surface 285 are in close contact with each other, and the sealing property of the part that partitions the SA accommodation area 290 and the measurement flow path 212 is improved. The SA flow path surface 285 is a flat surface that extends straight in a direction intersecting the height direction Y. In the present embodiment, the housing flow channel surface 275 and the SA flow channel surface 285 extend parallel to each other. In this case, since the housing partition portion 271 is in contact with the SA flow path surface 285, the sealability is improved at the portion where the outer surface of the sensor SA220 and the inner surface of the housing 201 are in contact. The housing flow channel surface 275 and the SA flow channel surface 285 may not be parallel to each other but may be relatively inclined.

The housing partition 271 is orthogonal to the housing flow path surface 275. In this case, the center line CL12 of the housing partition portion 271 and the housing flow passage surface 275 are orthogonal to each other. The housing partition 271 has a tapered shape. In the present embodiment, the height direction Y is the width direction for the housing partition 271, and the width dimension of the housing partition 271 in the width direction is gradually reduced toward the tip of the housing partition 271. .. Each of the pair of side surfaces of the housing partition portion 271 extends straight from the housing flow path surface 275. In this case, the housing partition 271 has a tapered cross section.

The housing partition 271 is provided at the center of the housing flow path surface 275 in the height direction Y. In this case, the distance between the housing distal end of the housing flow surface 275 and the housing partition 271 is the same as the distance between the housing proximal end of the housing flow surface 275 and the housing partition 271. .. The housing partition portion 271 may be provided at a position closer to the housing front end side on the housing flow passage surface 275, or may be provided at a position closer to the housing base end side.

A portion of the housing step surface 277 closer to the housing flow path surface 275 than the housing partition 271 forms a measurement flow path 212 together with the housing flow path surface 275. A portion on the housing accommodation surface 276 side of the housing partition portion 271 forms an SA accommodation area 290 together with the housing accommodation surface 276.

A portion of the SA step surface 287 closer to the SA flow path surface 285 than the housing partition 271 forms a measurement flow path 212 together with the SA flow path surface 285. A portion closer to the SA accommodation surface 286 than the housing partition 271 forms an SA accommodation area 290 together with the SA accommodation surface 286.

As shown in FIG. 38, the housing 201 has a base member 291 and a cover member 292. The base member 291 and the cover member 292 are assembled and integrated with each other, and the housing 201 is formed in this state. The base member 291 forms an upstream wall portion 231, a downstream wall portion 232, a back wall portion 234, a front end wall portion 235, a seal holding portion 205, a flange portion 207, and a connector portion 208 in the housing 201. The base member 291 is a box-shaped member that is open to the front side of the housing as a whole. In the base member 291, a base opening 291a is provided at the open end which is the front end. The base opening portion 291a is formed by the housing front side end portions of the upstream wall portion 231, the downstream wall portion 232, the tip end wall portion 235, and the seal holding portion 205, and the bypass flow passage 210 and the SA accommodation area 290 are located on the housing front side. It opens towards.

The cover member 292 forms the front wall portion 233 in the housing 201, and is a plate-shaped member as a whole. The cover member 292 is attached to the open end of the base member 291 and closes the base opening 291a. In the housing 201, the passage channel 211, the measurement channel 212, and the SA accommodation area 290 are provided between the base member 291 and the cover member 292.

In the housing 201, the first intermediate wall portion 236 has a first base convex portion 295 and a first cover convex portion 297. The first base protrusion 295 is a protrusion that protrudes from the back wall portion 234 of the base member 291 toward the cover member 292. The first base convex portion 295 has a first concave portion 295a. The first concave portion 295a is a concave portion provided on the tip surface of the first base convex portion 295, and penetrates the first base convex portion 295 in the height direction Y. The first cover protrusion 297 is a protrusion that protrudes from the front wall portion 233 of the cover member 292 toward the base member 291. The first cover convex portion 297 enters the inside of the first concave portion 295a. In the first intermediate wall portion 236, the tip end surface of the first cover convex portion 297 and the bottom surface of the first concave portion 295a are separated from each other, and the separated portion serves as the first intermediate hole 236a.

In the housing 201, the second intermediate wall portion 237 has a second base convex portion 296 and a second cover convex portion 298. The second base protrusion 296 is a protrusion that protrudes from the back wall portion 234 of the base member 291 toward the cover member 292. The second base convex portion 296 has a second concave portion 296a. The second concave portion 296a is a concave portion provided on the tip surface of the second base convex portion 296, and penetrates the second base convex portion 296 in the height direction Y. The second cover protrusion 298 is a protrusion that protrudes from the front wall portion 233 of the cover member 292 toward the base member 291. The second cover convex portion 298 enters the inside of the second concave portion 296a. In the second intermediate wall portion 237, the tip end surface of the second cover convex portion 298 and the bottom surface of the second concave portion 296a are separated from each other, and the separated portion is the second intermediate hole 237a.

The first base protrusion 295 and the second base protrusion 296 are included in the base member 291. The base protrusions 295 and 296 project from the back wall portion 234 of the base member 291 toward the cover member 292. Recesses 295a and 296a are provided on the tip surfaces of the base protrusions 295 and 296. The first recess 295a is provided at an intermediate position of the first base protrusion 295 in the depth direction Z. The second recess 296a is provided at an intermediate position of the second base protrusion 296 in the depth direction Z.

The first cover protrusion 297 and the second cover protrusion 298 are included in the cover member 292. The cover protrusions 297 and 298 project from the front wall portion 233 of the cover member 292 toward the base member 291.

The housing partition 271 has a base protrusion 271a and a cover protrusion 271b. The base protrusion 271a is included in the base member 291. The base protrusion 271a is a protrusion provided on the inner peripheral surface of the first recess 295a in the first base protrusion 295. The base protrusion 271a provided on the bottom surface of the first recess 295a extends in the width direction X toward the cover member 292. The base protrusions 271a provided on each of the pair of wall surfaces of the first recess 295a extend in the depth direction Z while facing each other. The distance between the base protrusions 271a facing each other provided on each of the pair of wall surfaces is slightly smaller than the width dimension in the depth direction Z of the portion of the sensor SA220 inserted into the first recess 295a. ..

The cover protrusion 271b is included in the cover member 292. The cover protrusion 271b is a protrusion provided on the tip surface of the first base protrusion 295, and extends in the width direction X toward the base member 291.

Next, a method of manufacturing the air flow meter 200 will be described with reference to FIGS. 38 and 39, centering on the procedure of mounting the sensor SA 220 in the housing 201.

The manufacturing process of the air flow meter 200 includes a process of manufacturing the sensor SA220, a process of manufacturing the base member 291, and a process of manufacturing the cover member 292. After these steps, a step of assembling the sensor SA220, the base member 291, and the cover member 292 with each other is performed.

In the process of manufacturing the sensor SA220, the molding part 225 of the sensor SA220 is manufactured by resin molding or the like using an injection molding machine or an injection molding device having a mold device. In this step, similarly to the step of manufacturing the mold part 55 of the first embodiment, the molten resin obtained by melting the resin material is injected from the injection molding machine and press-fitted into the mold device. Further, in this step, an epoxy thermosetting resin such as an epoxy resin is used as the resin material forming the mold portion 225.

In the step of manufacturing the base member 291, the base member 291 is manufactured by resin molding or the like using an injection molding device or the like. In the step of manufacturing the cover member 292, the cover member 292 is manufactured by resin molding or the like using an injection molding device or the like. In these steps, a thermoplastic resin such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS) is used as a resin material forming the base member 291 and the cover member 292. In this way, the base member 291 and the cover member 292 formed of the thermoplastic resin are softer than the mold portion 225 formed of the thermosetting resin. In other words, the base member 291 and the cover member 292 have lower hardness and higher flexibility than the mold portion 225.

In the step of assembling the sensor SA220, the base member 291, and the cover member 292, first, in FIG. 38, BH7, the sensor SA220 is inserted into the base member 291 through the base opening 291a. In this operation, the SA flow path surface 145 of the sensor SA220 is inserted into the first concave portion 295a, and the lead terminal 223a is inserted into the second concave portion 296a, so that the sensor SA220 and the first base convex portion 295 are inserted. 2 It fits in between the base convex portion 296. Here, after the SA flow path surface 285 of the sensor SA220 contacts the base protrusion 271a of the first base convex portion 295, the sensor SA220 is further pushed toward the back wall portion 234 into the base member 291. In this case, since the hardness of the base member 291 is lower than the hardness of the mold portion 225, the base protrusion 271a is deformed so that the tip portion thereof is crushed by the SA flow path surface 285 toward the back side of the housing.

As described above, on the inner peripheral surface of the first recess 295a of the base member 291, the base protrusion 271a is provided on each of the pair of wall surfaces facing each other. In this configuration, by simply fitting the sensor SA220 between the pair of wall surfaces, the sensor SA220 is in a state of scraping the tip portion of the base projection 271a on the wall at the SA flow path surface 285, and the base projection 271a on the wall is deformed. As a result, the tip surface newly formed by scraping the tip portion of the base protrusion 271a can be easily attached to the SA flow path surface 285 of the sensor SA220.

When the sensor SA220 is pushed into the first recess 295a, the SA flow path surface 285 of the sensor SA220 should crush the base projection 271a on the bottom of the inner peripheral surface of the first recess 295a toward the back wall portion 234. become. In this case, the tip end portion of the base protrusion 271a on the bottom surface is deformed so as to be crushed by the SA flow path surface 285, and the tip end portion newly formed by crushing the tip end portion of the base protrusion 271a is the SA of the sensor SA220. It becomes easy to adhere to the flow path surface 285.

Further, as described above, the cover protrusion 271b is provided on the tip end surface of the first cover protrusion 297 in the cover member 292. With this configuration, when the cover member 292 is assembled to the base member 291, the cover protrusion 271b of the cover member 292 is pressed against the SA flow path surface 285 of the sensor SA220. Therefore, by simply pressing the cover member 292 against the base member 291, the tip portion of the cover protrusion 271b of the first cover protrusion 297 is deformed so as to be crushed by the SA flow path surface 285. In this case, the tip portion of the cover protrusion 271b is crushed, so that the newly formed tip surface easily comes into close contact with the SA flow path surface 285 of the sensor SA220.

Then, the work of attaching the cover member 292 to the base member 291 is performed so that the cover member 292 covers the base opening 291a and the sensor SA220. In this operation, the first cover convex portion 297 of the cover member 292 is inserted into the first concave portion 295a. Here, after the cover protrusion 271b on the tip end surface of the first cover protrusion 297 comes into contact with the SA flow path surface 285 of the sensor SA220, the cover member 292 is further pressed toward the inside of the base member 291 against the sensor SA220. In this case, since the hardness of the cover member 292 is lower than the hardness of the mold portion 225, the cover protrusion 271b is deformed so that the tip portion thereof is crushed by the SA flow path surface 285 toward the front surface side of the housing. As a result, the tip end surface of the cover protrusion 271b in the crushed state is easily brought into close contact with the SA channel surface 285, and the sealing property between the cover protrusion 271b and the SA channel surface 285 is improved.

In the first embodiment, the crushed portion of the housing partition 131 is illustrated by a two-dot chain line in FIG. 17, but in the present embodiment, the sensor SA220 crushes the base protrusion 271a and the cover protrusion 271b. The drawn portion is not shown by a chain double-dashed line.

After that, the sensor SA220, the base member 291, and the cover member 292 are fixed to each other by joining the contact portion between the base member 291 and the cover member 292 with an adhesive or the like. In this case, the housing 201 is formed by integrating the base member 291 and the cover member 292. Further, in this case, the housing partition 271 is formed by the base protrusion 271a and the cover protrusion 271b.

According to the present embodiment described thus far, the housing partition portion 271 protruding from the inner surface of the housing 201 partitions the measurement flow path 212 and the SA accommodation area 290 between the sensor SA220 and the housing 201. In this configuration, since the tip of the housing partition 271 and the sensor SA220 are likely to come into close contact with each other, a gap is unlikely to be formed between the inner surface of the housing 201 and the outer surface of the sensor SA220. Therefore, when the molten potting resin is injected into the SA accommodation area 290 of the housing 201 to form the filling portion, the potting resin may enter the measurement flow channel 212 through the gap between the housing 201 and the sensor SA220. Regulated.

In this case, it is less likely that the molten resin that has entered the measurement channel 212 through the gap between the housing 201 and the sensor SA 220 is solidified and the solidified portion causes the shape of the measurement channel 212 to change unintentionally. There is. Further, it is less likely that the solidified portion will be peeled off from the housing 201 or the sensor SA 220 in the measurement flow path 212 and come into contact with or adhere to the flow rate sensor 202 as a foreign matter. Therefore, it is possible to prevent the detection accuracy of the flow rate sensor 202 from being lowered by the molten resin that has entered the measurement flow path 212 from the SA accommodation area 290. Thereby, the detection accuracy of the air flow rate by the flow rate sensor 202 can be improved, and as a result, the measurement accuracy of the air flow rate by the air flow meter 200 can be improved.

According to the present embodiment, the housing partition portion 271 makes a circle around the sensor SA220. With this configuration, the housing partition portion 271 can create a state in which the outer surface of the sensor SA 220 and the inner surface of the housing 201 are in close contact with each other over the entire outer surface of the sensor SA 220. Therefore, the housing partition portion 271 can enhance the sealing property in the entire boundary portion between the measurement flow channel 212 and the SA accommodation area 290.

In the present embodiment, the housing partition 271 is provided on the housing flow passage surface 275. In this configuration, the housing partition 271 partitions the measurement channel 212 and the SA accommodation area 290 at a position as close to the measurement channel 212 as possible, so that the measurement channel 32 is provided in the gap between the housing 201 and the sensor SA220. The included part can be made as small as possible. Here, in the measurement flow path 212, the gap between the housing 201 and the sensor SA 220 is a region where the air flowing from the measurement inlet 215 toward the measurement outlet 216 is likely to cause turbulence in the air flow. There is. Therefore, as the gap between the housing 201 and the sensor SA 220 is smaller, the flow of air is less likely to be disturbed in the measurement flow path 212, and the detection accuracy of the flow rate sensor 202 is likely to be improved. Therefore, since the housing partition portion 271 is provided on the housing flow passage surface 275, the detection accuracy of the flow rate sensor 202 can be improved.

(Third Embodiment)
In the first embodiment described above, the passage channel 31 is not narrowed in the height direction Y from the passage inlet 33 toward the measurement inlet 35, but in the third embodiment, the passage passage 33 is measured from the passage inlet 33. The passage channel 31 is narrowed in the height direction Y toward the inlet 35. In the present embodiment, the components denoted by the same reference numerals as those in the drawings in the first embodiment and the configuration not described are the same as those in the first embodiment, and have the same operational effects. In this embodiment, differences from the first embodiment will be mainly described.

<Explanation of configuration group C>
As shown in FIGS. 40 and 41, the passage passage 31 has an inlet passage 331, an outlet passage 332, and a branch passage 333. The inlet passage 331 extends from the passage inlet 33 toward the passage outlet 34 and spans the passage inlet 33 and the upstream end of the measurement inlet 35. The outlet passage 332 extends from the passage outlet 34 toward the passage inlet 33 and spans the passage outlet 34 and the downstream end of the measurement inlet 35. The branch passage 333 is provided between the entrance passage 331 and the exit passage 332, and connects the entrance passage 331 and the exit passage 332. The branch passage 333 extends in the depth direction Z along the measurement inlet 35 and is a portion of the passage passage 31 where the measurement passage 32 is branched. The branch passage 333 extends from the measurement inlet 35 toward the front end side of the housing.

The inner surface of the housing 21 has a passage ceiling surface 341 and a passage floor surface 345 as formation surfaces forming the passage passage 31. The passing ceiling surface 341 and the passing floor surface 345 are arranged in the height direction Y, and the passing passage 31 is provided between the passing ceiling surface 341 and the passing floor surface 345. The passage ceiling surface 341 and the passage floor surface 345 are bridged over the passage inlet 33 and the passage outlet 34. Both the passing ceiling surface 341 and the passing floor surface 345 intersect in the height direction Y and extend in the width direction X and the depth direction Z. A measurement outlet 36 is provided on the passing ceiling surface 341.

The passing ceiling surface 341 has an entrance ceiling surface 342 and an exit ceiling surface 343. The entrance ceiling surface 342 forms the ceiling surface of the entrance passage 331, and extends over the passage entrance 33 and the upstream end of the measurement entrance 35 in the depth direction Z. In this case, the depth direction Z corresponds to the direction in which the passage inlet 33 and the passage outlet 34 are lined up. The entrance ceiling surface 342 extends straight from the passage entrance 33 toward the upstream end of the measurement entrance 35. The outlet ceiling surface 343 forms the ceiling surface of the outlet passage 332, and extends over the passage outlet 34 and the downstream end of the measurement inlet 35. The outlet ceiling surface 343 extends straight from the passage outlet 34 toward the downstream end of the measurement inlet 35.

The passing floor surface 345 has an entrance floor surface 346, an exit floor surface 347, and a branch floor surface 348. The entrance floor surface 346 forms a floor surface of the entrance passage 331, and extends from the entrance 33 to the exit 34. The entrance floor surface 346 and the entrance ceiling surface 342 face each other via the entrance passage 331 and the passage entrance 33. The outlet floor surface 347 forms the floor surface of the outlet passage 332, and extends from the passage outlet 34 toward the passage inlet 33. The outlet floor surface 347 and the outlet ceiling surface 343 face each other via the outlet passage 332 and the passage outlet 34. The branch floor surface 348 forms the floor surface of the branch passage 333. The branch floor surface 348 is provided between the entrance floor surface 346 and the exit floor surface 347, and connects the entrance floor surface 346 and the exit floor surface 347. The branch floor surface 348 faces the measurement inlet 35 via the branch passage 333.

The entrance ceiling surface 342 and the exit ceiling surface 343 both extend straight in the depth direction Z and are parallel to each other. Further, both of the ceiling surfaces 342 and 343 extend straight in the width direction X and are parallel to each other. The passing floor surface 345 extends straight in the depth direction Z and is parallel to the ceiling surfaces 342 and 343. The passing floor surface 345 extends straight in the width direction X and is parallel to the ceiling surfaces 342 and 343. In this way, the ceiling surfaces 342 and 343 and the passing floor surface 345 extend straight in the width direction X, and passing wall surfaces 631 and 632 (see FIG. 31) described later extend straight in the height direction Y. Due to this, the passage inlet 33 and the passage outlet 34 have a rectangular shape.

In addition, the entrance ceiling surface 342, the exit ceiling surface 343, and the passing floor surface 345 may be curved so that the portion between the upstream end portion and the downstream end portion in the depth direction Z is recessed or bulged. Further, the entrance ceiling surface 342, the exit ceiling surface 343, and the passage floor surface 345 may be curved so that the portion between the passage wall surfaces 631 and 632 in the width direction X is recessed or bulged. As described above, the passage inlet 33 and the passage outlet 34 may be curved so that at least one side is recessed or bulged. That is, the passage inlet 33 and the passage outlet 34 do not have to be rectangular. For example, the entrance ceiling surface 342, the exit ceiling surface 343, and the passage floor surface 345 are curved so that the portion between the passage wall surfaces 631 and 632 is swollen, so that the passage entrance 33 and the passage outlet 34 in the width direction X. The extending sides may be curved so as to bulge.

The entrance ceiling surface 342 is inclined with respect to the entrance floor surface 346 so as to face the passage entrance 33 side. The inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346 is 10 degrees or more. That is, the inclination angle θ21 is the same value as 10 degrees or a value larger than 10 degrees, and the relationship of θ21≧10 is established. As shown in FIG. 41, assuming the floor parallel line CL21 as a virtual straight line extending parallel to the entrance floor surface 346, the inclination angle θ21 is between the entrance ceiling surface 342 and the floor parallel line CL21 and the passage entrance 33. It is the angle of the part that points to the side. In the passage ceiling surface 341, the inclination angle with respect to the floor parallel line CL21 is different between the entrance ceiling surface 342 and the exit ceiling surface 343. Specifically, the inclination angle θ21 of the entrance ceiling surface 342 with respect to the floor parallel line CL21 is larger than the inclination angle of the exit ceiling surface 343 with respect to the floor parallel line CL21.

The entrance ceiling surface 342 corresponds to the ceiling inclined surface. The configuration of the present embodiment is basically the same as the configuration of the first embodiment except that the entrance ceiling surface 342 faces the passage entrance 33 side. Is also the description of the first embodiment.

In the entrance passage 331, the separation distance H21 between the entrance ceiling surface 342 and the entrance floor surface 346 in the height direction Y gradually decreases from the entrance 33 to the exit 34. The height direction Y here is a direction orthogonal to the main streamline CL22. The reduction rate of the separation distance H21 is a constant value in the entrance passage 331.

The passing floor surface 345 extends straight in the depth direction Z. In the passage floor surface 345, the entrance floor surface 346, the exit floor surface 347, and the branch floor surface 348 form the same plane. As shown in FIG. 41, assuming the main streamline CL22 as a virtual straight line extending in the depth direction Z which is the mainstream direction, the passage floor surface 345 is inclined with respect to the main streamline CL22 so as to face the passage inlet 33 side. There is. In this case, each of the inlet floor surface 346, the outlet floor surface 347, and the branch floor surface 348 is inclined with respect to the main streamline CL22. As described above, the main streamline CL22 extends parallel to the angle setting surface 27a due to the angle setting surface 27a of the flange portion 27 extending in the mainstream direction.

The entrance ceiling surface 342 is inclined with respect to the main streamline CL22 in addition to the entrance floor surface 346. The inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22 is 10 degrees or more, similarly to the inclination angle θ21. That is, the inclination angle θ22 is the same value as 10 degrees or a value larger than 10 degrees, and the relationship of θ22≧10 is established. In this embodiment, the inclination angle θ22 is set to, for example, 10 degrees. As shown in FIG. 41, the inclination angle θ22 is the angle of the portion facing the passage entrance 33 side between the entrance ceiling surface 342 and the main streamline CL22. The inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22 is smaller than the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346.

The inlet passage 331 has a shape that is gradually narrowed from the passage inlet 33 toward the passage outlet 34 by at least the inlet ceiling surface 342 and the inlet floor surface 346. In this case, as shown in FIG. 42, the cross-sectional area S21 of the entrance passage 331 in the directions X and Y orthogonal to the main streamline CL22 gradually decreases from the entrance 33 to the exit 34. This cross-sectional area S21 has the largest value at the passage inlet 33, which is the upstream end of the inlet passage 331, and has the smallest value at the downstream end of the inlet passage 331. The reduction rate of the cross-sectional area S21 has a constant value in the inlet passage 331, and the graph showing the value of the cross-sectional area S21 in the inlet passage 331 extends linearly as shown in FIG.

The outlet passage 332 has a shape that is gradually narrowed from the upstream end of the outlet passage 332 toward the passage outlet 34. In this case, the cross-sectional area of the outlet passage 332 in the directions X and Y orthogonal to the main streamline CL22 gradually decreases from the upstream end of the outlet passage 332 toward the passage outlet 34. The cross-sectional area of the inlet passage 331 can also be referred to as the flow passage area of the inlet passage 331.

As shown in FIG. 40, the measurement flow path 32 has a folded shape that is folded back between the measurement inlet 35 and the measurement outlet 36. The measurement flow path 32 has a branch measurement path 351, a guide measurement path 352, a detection measurement path 353, and a discharge measurement path 354. In the measurement flow path 32, the branch measurement path 351, the guide measurement path 352, the detection measurement path 353, and the discharge measurement path 354 are arranged in this order from the measurement inlet 35 side toward the measurement outlet 36.

The branch measurement path 351 extends from the measurement inlet 35 toward the base end side of the housing, and is a portion of the measurement flow path 32 branched from the passage flow path 31. The branch measurement path 351 forms the measurement inlet 35, and the upstream end of the branch measurement path 351 serves as the measurement inlet 35. The branch measurement path 351 is inclined with respect to both the height direction Y and the depth direction Z. The branch measurement path 351 is inclined with respect to the passage flow path 31.

The guide measurement path 352 extends in the height direction Y from the downstream end of the branch measurement path 351 toward the side opposite to the passage flow path 31. The guide measurement path 352 guides the air flowing in from the branch measurement path 351 toward the flow rate sensor 22.

The detection measurement path 353 extends in the depth direction Z from the downstream end of the guide measurement path 352, and is provided on the opposite side of the branch measurement path 351 via the guide measurement path 352. The flow rate sensor 22 is provided in the detection measurement path 353.

The discharge measurement passage 354 extends in the height direction Y from the downstream end of the detection measurement passage 353 toward the passage passage 31 side, and is provided in parallel with the guide measurement passage 352. The discharge measurement path 354 forms the measurement outlet 36, and the downstream end of the discharge measurement path 354 is the measurement outlet 36. In this case, the discharge measurement path 354 discharges the air flowing from the detection measurement path 353 from the measurement outlet 36.

As shown in FIG. 41, the branch measurement path 351 has a portion that extends straight from the measurement inlet 35 toward the guide measurement path 352. When the center line of this portion is referred to as a branch measurement line CL23, the branch measurement line CL23 extends linearly while being inclined with respect to the entrance ceiling surface 342. The branch measurement line CL23 extends obliquely from the measurement inlet 35 toward the downstream side of the branch measurement path 351 on the side opposite to the passage inlet 33. In other words, the branch measurement line CL23 extends obliquely from the measurement inlet 35 toward the downstream side of the branch measurement path 351 toward the passage outlet 34 side.

Note that, in FIG. 41, the inner surface of the housing 21 is chamfered at the branch portion between the passage channel 31 and the measurement channel 32, but the branch measurement line CL23 is set assuming a configuration without this chamfer. The branch measurement line CL23 is also an extension line that extends the center line of the branch measurement path 351 at the measurement inlet 35 toward the passage channel 31 side.

The branch measurement line CL23 is inclined with respect to the entrance floor surface 346. The inclination angle θ23 of the branch measurement line CL23 with respect to the entrance floor surface 346 is 90 degrees or more. That is, the inclination angle θ23 is the same value as 90 degrees or a value larger than 90 degrees, and the relationship of θ23≧90 is established. The inclination angle θ23 is the angle between the floor parallel line CL21 and the branch measurement line CL23 and facing the passage entrance 33 side. In addition, in the range of 90 degrees or more, θ23 is preferably 150 degrees or less, and more preferably 120 degrees or less.

The branch measurement line CL23 is inclined with respect to the main streamline CL22 in addition to the entrance floor surface 346. The inclination angle θ24 of the branch measurement line CL23 with respect to the main stream line CL22 is 90 degrees or more, similarly to the inclination angle θ23. That is, the inclination angle θ24 is the same value as 90 degrees or a value larger than 90 degrees, and the relationship of θ24≧90 is established. The inclination angle θ24 is the angle between the main streamline CL22 and the branch measurement line CL23 and the portion facing the passage inlet 33 side. The inclination angle θ24 is included in the obtuse angle. Further, in the range of 90 degrees or more, θ24 is preferably 150 degrees or less, and more preferably 120 degrees or less.

The inclination angles θ23 and θ24 are included in the obtuse angle. The branch measurement line CL23 is inclined with respect to the entrance ceiling surface 342 in addition to the entrance floor surface 346 and the main streamline CL22. The inclination angle of the branch measurement line CL23 with respect to the entrance ceiling surface 342 is 10 degrees or more, like the inclination angles θ23 and θ24.

The branch measurement path 351 is inclined with respect to the entrance passage 331. In this case, the branch measurement line CL23 that is the center line of the branch measurement path 351 is inclined with respect to the entrance passage line CL24 that is the center line of the entrance passage path 331. The inclination angle θ25 of the branch measurement line CL23 with respect to the entrance passage line CL24 is 90 degrees or more. That is, the inclination angle θ25 has the same value as 90 degrees or a value larger than 90 degrees, and the relationship of θ25≧90 is established. The inclination angle θ25 is an angle between the branch measurement line CL23 and the entrance passage line CL24 and facing the passage entrance 33 side. The inlet passage line CL24 is a straight line imaginary line that passes through the center CO21 of the measurement inlet 35 that is the upstream end of the inlet passage 331 and the center CO22 of the downstream end of the inlet passage 331.

The branch measurement path 351 is inclined with respect to the exit passage 332. In this case, the branch measurement line CL23 is inclined with respect to the exit passage line CL25 which is the center line of the exit passage 332. The inclination angle θ26 of the branch measurement line CL23 with respect to the exit passage line CL25 is 60 degrees or less. That is, the inclination angle θ26 is the same value as 60 degrees or a value smaller than 60 degrees, and the relationship of θ26≦60 is established. The inclination angle θ26 is set to, for example, 60 degrees. The outlet passage line CL25 is a straight imaginary line that passes through the center CO23 at the upstream end of the outlet passage 332 and the center CO24 of the passage outlet 34 that is the downstream end of the outlet passage 332. Further, the exit passage line CL25 is inclined with respect to the entrance passage line CL24.

The inclination angle θ26 of the branch measurement line CL23 with respect to the outlet passage line CL25 is the inclination angle of the branch measurement line 351 with respect to the branch passage line 333, and is a branch angle indicating the angle at which the measurement flow passage 32 branches from the passage flow passage 31. Equivalent to.

Next, the mode of air flow in the bypass passage 30 will be described with reference to FIGS. 43 to 46. The airflows flowing through the intake passage 12 include main flows AF21 and AF22 and non-uniform flows AF23 to AF26.

As shown in FIG. 43, the mainstreams AF21 and AF22 flow in the intake passage 12 along the mainstream line CL22 in the mainstream direction, and flow into the inlet passageway 331 from the passage inlet 33 in the direction of the flow. Of the mainstreams AF21 and AF22, the mainstream AF21 flowing into the entrance ceiling surface 342 from the passage entrance 33 advances toward the entrance ceiling surface 342, and when approaching the entrance ceiling surface 342, the direction in which the entrance ceiling surface 342 advances changes. .. In this case, the entrance ceiling surface 342 changes the traveling direction of the mainstream AF 21 toward the passing floor surface 345. For this reason, even if foreign matter such as dust enters from the passage inlet 33 together with the mainstream AF 21, the foreign matter easily advances toward the passage floor surface 345, and the foreign matter does not easily enter the measurement inlet 35.

On the other hand, the mainstream AF 22 flowing from the passage entrance 33 toward the entrance floor surface 346 advances toward the passage floor surface 345 such as the entrance floor surface 346 and the branch floor surface 348, and when approaching the passage floor surface 345, the passage floor surface 345. The direction to move changes. In this case, the passing floor surface 345 changes the traveling direction of the mainstream AF 22 toward the passing outlet 34. Therefore, even if the foreign matter enters from the passage inlet 33 together with the mainstream AF 22, the foreign matter easily travels along the passage floor surface 345 toward the passage outlet 34, and the foreign matter does not easily enter the measurement inlet 35. ..

As shown in FIGS. 44 and 45, the non-uniform flows AF23 to AF26 flow in the intake passage 12 in a direction inclined with respect to the main stream line CL22 and the main flow direction, and the flow direction is maintained from the passage inlet 33 to the inlet passage. It flows into 331.

As shown in FIG. 44, among the drifts AF23 to AF26, the downward drifts AF23 and AF24 are airflows that obliquely advance in the intake passage 12 from the housing base end side toward the housing front end side around the housing 21. Here, the airflows whose inclination angle with respect to the main streamline CL22 is smaller than that of the entrance ceiling surface 342 are defined as downward drifts AF23 and AF24.

Among the downward biased flows AF23 and AF24, the downward biased flow AF23 flowing into the entrance ceiling surface 342 side from the passage entrance 33 easily advances toward the passage floor surface 345 along the entrance ceiling surface 342. In particular, if the downward biased flow AF 23 and the entrance ceiling surface 342 have substantially the same inclination angle with respect to the mainstream direction, the direction in which the downward biased flow AF 23 advances is unlikely to change due to the entrance ceiling surface 342. In these cases, even if the foreign matter enters from the passage entrance 33 together with the downward drift AF 23, the foreign matter easily advances toward the passing floor surface 345, and the foreign matter does not easily enter the measurement entrance 35.

On the other hand, the downward biased flow AF 24 flowing from the passage entrance 33 toward the entrance floor surface 346 advances toward the passage floor surface 345, and when approaching the passage floor surface 345, the direction of advance by the passage floor surface 345 changes. In this case, the passing floor surface 345 changes the advancing direction of the downward drift AF 24 toward the passing outlet 34. In this case, even if the foreign matter enters from the passage inlet 33 together with the downward-biased AF 24, the foreign matter is likely to travel along the passage floor surface 345 toward the passage outlet 34, and the foreign matter rarely enters the measurement inlet 35. Become.

As shown in FIG. 45, among the drifts AF23 to AF26, the upward drifts AF25 and AF26 are airflows that obliquely travel in the intake passage 12 from the housing front end side toward the housing base end side around the housing 21. Here, the airflows whose inclination angle with respect to the main streamline CL22 is larger than the inlet floor surface 346 are defined as upward drifts AF25 and AF26.

Out of the upward drifts AF25 and AF26, the upward drift AF25 flowing into the entrance ceiling surface 342 from the passage entrance 33 advances toward the entrance ceiling surface 342, and when approaching the entrance ceiling surface 342, the entrance ceiling surface 342 advances in a direction. Change. In this case, the entrance ceiling surface 342 changes the direction in which the upward-flowing drift AF 25 advances toward the passage floor surface 345. For this reason, even if a foreign matter such as dust enters together with the upward biased flow AF 25 from the passage entrance 33, the foreign matter easily advances toward the passage floor surface 345, and the foreign matter does not easily enter the measurement entrance 35.

On the other hand, the upward biased flow AF 26 that has flowed from the passage entrance 33 to the entrance floor surface 346 side easily advances toward the entrance ceiling surface 342 and the measurement entrance 35. That is, the upward-direction drift AF 26 easily flows in the direction away from the passing floor surface 345 such as the inlet floor surface 346 after flowing into the inlet passage 331 from the passing inlet 33. In this case, separation of the upward biased flow AF 26 from the passing floor surface 345 causes a vortex AF27 that flows so as to wrap around the passing floor surface 345, and the flow of the upward biased flow AF 26 is easily disturbed. When the flow of the upward biased flow AF 26 is disturbed in this way, the flow of the upward biased flow AF 26 also disturbs the flow of the upward biased flow AF 25 on the inlet ceiling surface 342 side, and thus the air flow tends to be disturbed throughout the passage channel 31. In this case, there is a concern that the turbulent airflow may flow from the measurement inlet 35 into the measurement flow path 32, and the flow rate detection accuracy of the flow rate sensor 22 may deteriorate.

On the other hand, since the upward biased flow AF25, which has been turned by the entrance ceiling surface 342, is advancing toward the passing floor surface 345, the upward biasing current AF25 presses the upward biasing flow AF26 toward the passing floor surface 345. It becomes a state. In this case, the upward biased flow AF25 advancing toward the passing floor surface 345 changes the advancing direction of the upward biased flow AF26 on the inlet floor surface 346 side toward the passing floor surface 345. For this reason, it is unlikely that the upward biased flow AF 26 separates from the passing floor surface 345, and as a result, the eddy current AF 27 that accompanies separation is also unlikely to occur. Therefore, the turbulence of the air flow in the passage 31 due to the generation of the vortex AF 27 is suppressed.

In the air flow meter 20, the variation mode of the output related to the flow rate measurement is correlated with the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346. Specifically, when the variation of the measured value of the air flow meter 20 with respect to the true air flow rate in the intake passage 12 is calculated as the output variation, the output variation is the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346. Is properly managed with a configuration of 10 degrees or more. For example, in a range where the inclination angle θ21 is larger than 0 degree and smaller than 10 degrees, the output fluctuation of the air flow meter 20 becomes smaller as the inclination angle θ21 is closer to 10 degrees. Then, in a range in which the inclination angle θ21 is 10 degrees or more, the output fluctuation of the air flow meter 20 is appropriately kept at a small value. The inclination angle θ21 is preferably 60 degrees or less, and more preferably 30 degrees or less in the range of 10 degrees or more.

The output fluctuation of the air flow meter 20 is also correlated with the inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22. This output fluctuation is properly managed by the configuration in which the inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22 is 10 degrees or more. For example, as shown in FIG. 46, in the range where the inclination angle θ22 is larger than 0 degrees and smaller than 10 degrees, the output fluctuation of the air flow meter 20 is smaller as the inclination angle θ22 is closer to 10 degrees. Then, in a range in which the inclination angle θ22 is 10 degrees or more, the output fluctuation of the air flow meter 20 is appropriately kept at a small value. The inclination angle θ22 is preferably 60 degrees or less, and more preferably 30 degrees or less in the range of 10 degrees or more.

In the intake passage 12 shown in FIG. 41, when a pulsation occurs in the flow of intake air due to an engine operating condition or the like, with this pulsation, in addition to the forward flow flowing from the upstream side, the forward flow from the downstream side is A backflow that flows in the opposite direction may occur. It is feared that the forward flow will flow into the passage channel 31 from the passage inlet 33, while the reverse flow will flow into the passage channel 31 from the passage outlet 34. For example, when a forward flow flows in from the passage inlet 33 and further flows from the passage passage 31 into the measurement passage 32, the flow rate of the forward flow is detected by the flow sensor 22. On the other hand, when the backflow generated in the intake passage 12 flows in from the passage outlet 34 and further flows from the passage passage 31 into the measurement passage 32, the flow rate of this backflow is detected by the flow sensor 22.

The flow rate sensor 22 is capable of detecting the flow rate of air in the measurement flow channel 32 as well as the flow rate of air in the measurement flow channel 32. However, when the backflow flowing from the passage outlet 34 flows into the measurement flow passage 32, the backflow flows from the measurement inlet 35 toward the measurement outlet 36 in the same manner as the forward flow flowing from the passage inlet 33. become. As described above, in the measurement flow path 32, the direction in which the reverse flow that flows in from the passage outlet 34 flows and the direction in which the forward flow that flows in from the passage inlet 33 flow are the same, so the flow rate sensor 22 distinguishes between the forward flow and the reverse flow. Cannot be detected. Therefore, although the air flowing through the measurement flow channel 32 actually contains a backflow, the air flow meter 20 measures the flow rate of the air assuming that all the air flowing through the measurement flow channel 32 is a forward flow. It will be decided. As a result, there is a concern that the measurement accuracy of the air flow meter 20 may be reduced.

Further, in the intake passage 12, turbulence of the airflow such as vortex or stagnation may occur as the air passes around the airflow meter 20. For example, when the air flowing as a forward flow in the intake passage 12 passes through the housing front surface 21e and the housing back surface 21f, there are a flow that tries to proceed in the mainstream direction and a flow that tries to travel along the housing downstream surface 21d. Airflow turbulence may occur when mixed. When the turbulence of the airflow exists in the vicinity of the passage outlet 34 such as the downstream side of the housing downstream surface 21d, when a backflow occurs in the intake passage 12, the backflow becomes unstable due to the turbulence of the airflow. It is feared that an unstable backflow enters the passage channel 31 from the passage outlet 34.

Therefore, in the air flow meter 20, even if a backflow flows from the passage outlet 34 into the passage passage 31, the branch measurement passage 351 extends from the passage passage 31 toward the passage outlet 34 side, so that the backflow passes. It is difficult for the flow path 31 to flow into the branch measurement path 351. In particular, as described above, since the inclination angle θ26 of the branch measurement line CL23 with respect to the outlet passage line CL25 is 60 degrees or less, it is even less likely that a backflow will flow from the passage channel 31 into the branch measurement channel 351. ing.

In the bypass passage 30, the measurement inlet 35 does not face the passage inlet 33 side as described above. Therefore, the dynamic pressure of the forward flow flowing in from the passage inlet 33 is hard to be applied to the measurement inlet 35, and the flow velocity of the air in the measurement flow passage 32 tends to increase. Further, in this configuration, even if foreign matter such as sand dust, dust, water droplets, oil drops, etc. enters the passage channel 31 from the passage inlet 33 along with the forward flow, this foreign matter is unlikely to enter the branch measurement channel 351 from the passage channel 31. Has become. In this case, the foreign matter reaching the flow rate sensor 22 in the measurement flow path 32 is less likely to damage the flow rate sensor 22 or adhere to the flow rate sensor 22, so that the foreign matter reduces the detection accuracy of the flow rate sensor 22. That is suppressed.

The entire passage outlet 34 and at least a part of the passage inlet 33 overlap in the depth direction Z, which is the mainstream direction. With this configuration, when foreign matter is contained in the main flow that has flowed into the portion of the passage inlet 33 that overlaps the passage outlet 34 in the depth direction Z in the intake passage 12, the foreign matter advances straight along with the main stream in the mainstream direction. As a result, it is discharged from the passage outlet 34 to the outside. Therefore, it is difficult for foreign matter to enter the measurement inlet 35.

The state of pulsation generated in the intake passage 12 is referred to as pulsation characteristic. The pulsation characteristic measured by the air flow meter 20 using the detection result of the flow rate sensor 22 is different from the pulsation characteristic of the pulsation actually generated in the intake passage 12. Error may be included. As a case where the pulsation characteristic measured by the air flow meter 20 includes an error, there is a case where a backflow flowing from the passage outlet 34 enters the measurement passage 32 from the passage passage 31.

Here, the flow rate measured by the air flow meter 20 is referred to as a flow rate measurement value GA, the average value of this flow rate measurement value GA is referred to as a measurement average value GAave, and the actual flow rate of the intake air flowing through the intake passage 12 is referred to as the actual flow rate GB. The average value of the actual flow rate GB is referred to as an actual average value GBave. As shown in FIG. 47, when the flow rate measurement value GA has a value smaller than the actual flow rate GB because the flow rate measurement value GA includes an error, the measured average value GAave also becomes smaller than the actual average value GBave.

The pulsation characteristic can be digitized by a value obtained by dividing the difference between the measured average value GAave and the actual average value GBave by the actual average value GBave. In this case, the mathematical expression for calculating the pulsation characteristic can be expressed as (GAave-GBave)/GBave. The pulsation characteristic value tends to increase as the pulsation amplitude increases. For example, when a value obtained by dividing the difference between the maximum value GBmax of the actual flow rate GB and the actual average value GBave by the actual average value GBave is referred to as an amplitude ratio, as shown in FIG. 48, as shown in FIG. The number increases. In particular, in a region where the amplitude ratio is larger than 1, the rate of increase of the pulsation characteristic increases with the increase of the amplitude ratio. Here, the larger the amplitude ratio, the larger the amount of backflow from the passage outlet 34. The mathematical expression for calculating the amplitude ratio can be expressed as (GBmax-GBave)/GBave.

In the present embodiment, the inclination angle θ26 of the branch measurement line CL23 with respect to the main streamline CL22 is set to, for example, 60 degrees, but the numerical value of the pulsation characteristic is likely to change according to the inclination angle θ26. For example, as shown in FIG. 49, when a backflow is made to flow from the passage outlet 34 into the passage channel 31 in the configuration where the inclination angle θ26 is 30, 45, 60 and 90 degrees, the inclination angle θ26 is 30 degrees, With the configuration of 45 degrees and 60 degrees, it is difficult for backflow to flow into the measurement flow channel 32. On the other hand, when the inclination angle θ26 is 90 degrees, the backflow is likely to flow into the measurement flow channel 32. In this case, the accuracy of detection of the pulsation characteristic by the air flow meter 20 is likely to decrease.

In the air flow meter 20, it is considered that the easiness of backflow into the measurement flow channel 32 differs depending on the inclination angle θ26, and as a result, the numerical values of the pulsation characteristics differ. For example, as shown in FIG. 50, when the inclination angle θ26 is 60 degrees or less, the numerical value of the pulsation characteristic is a relatively small value. It is considered that this is because the backflow is difficult to flow into the measurement flow channel 32 when the inclination angle θ26 is 60 degrees or less. On the other hand, in the configuration in which the inclination angle θ26 is larger than 60 degrees, the numerical value of the pulsation characteristic is relatively large. It is considered that this is because the backflow easily flows into the measurement flow path 32 when the inclination angle θ26 is larger than 60 degrees. Moreover, in this configuration, the numerical value of the pulsation characteristic increases as the inclination angle θ26 increases. It is considered that this is because the backflow is more likely to flow into the measurement flow channel 32 as the inclination angle θ26 increases in the range where the inclination angle θ26 is larger than 60 degrees.

According to the present embodiment described thus far, the entrance ceiling surface 342 is inclined with respect to the entrance floor surface 346. In this configuration, of the air flowing into the entrance passage 331 from the passage entrance 33, the upwardly-displaced airflow AF25, etc., flowing into the entrance ceiling surface 342 is changed in the advancing direction by the entrance ceiling surface 342, and the entrance ceiling surface 342 is changed. It becomes easy to follow along to the entrance floor surface 346. Therefore, even if the air such as the upward-flowing drift AF 26 is separated from the entrance floor surface 346 or is about to be separated, the separated air travels along the entrance ceiling surface 342 toward the entrance floor surface 346. It is pressed against the inlet floor surface 346 by the air such as the nonuniform flow AF25. In this case, the occurrence of turbulence such as vortex due to the separation of air from the inlet floor surface 346 is restricted by the fluid flowing along the inlet ceiling surface 342, and as a result, the turbulence of air is less likely to occur in the inlet passage 331. .. Therefore, the flow rate detection accuracy of the flow rate sensor 22 can be improved, and the flow rate measurement accuracy of the air flow meter 20 can be improved.

According to this embodiment, the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346 is 10 degrees or more. In this configuration, the inclination angle θ21 is set to a relatively large value so that the air, such as the upward drift AF25 whose direction of travel is changed by the entrance ceiling surface 342, advances toward the entrance floor surface 346 instead of the passage exit 34. There is. Therefore, as compared with the configuration in which the inclination angle θ21 is set to a value smaller than 10 degrees, for example, the air flows upward near the entrance floor surface 346 due to the air such as the upward drift AF25 whose traveling direction is changed by the entrance ceiling surface 342. It is possible to reliably suppress the occurrence of peeling.

According to this embodiment, the entrance ceiling surface 342 is inclined with respect to the entrance floor surface 346 so as to face the passage entrance 33 side. In this configuration, air such as the mainstream AF 21 and the downward-flowing drift AF 23 that has flowed from the passage entrance 33 to the entrance ceiling surface 342 side is less likely to be separated from the entrance ceiling surface 342. Therefore, it is possible to suppress the occurrence of turbulence or other turbulence in the air flowing from the passage entrance 33 to the entrance ceiling surface 342 side.

For example, in a configuration in which the entrance ceiling surface 342 is inclined with respect to the entrance floor surface 346 so as to face the passage outlet 34 side, the mainstream AF 21 flowing from the passage entrance 33 to the entrance ceiling surface 342 side proceeds toward the passage outlet 34. The farther it is from the entrance ceiling surface 342, the easier it is to peel off. In this case, the turbulence of the airflow is likely to occur in the passage 31 due to the generation of vortexes and the like by the mainstream AF 21.

According to this embodiment, the entrance ceiling surface 342 is inclined so as to face the passage entrance 33 with respect to the mainstream direction in which the mainstream line CL22 extends. With this configuration, when air such as the mainstream AF21 flowing in the mainstream direction flows into the entrance ceiling surface 342 side from the passage entrance 33, the air can be guided to the entrance floor surface 346 side by the entrance ceiling surface 342. Therefore, even if air such as the mainstream AF22 that flows in the mainstream direction flows into the inlet floor surface 346 side from the passage inlet 33 and is peeled off or is likely to be peeled off, this air is passed from the inlet ceiling surface 342 to the inlet floor surface 342. Air advancing toward surface 346 can be pressed against inlet floor 346. Therefore, it is possible to suppress the occurrence of turbulence such as the vortex AF27 in the airflow around the entrance floor surface 346.

According to this embodiment, the inclination angle θ22 of the entrance ceiling surface 342 with respect to the mainstream direction is 10 degrees or more. In this configuration, among the downward drifts that obliquely proceed from the housing base end side toward the housing front end side around the housing 21, the downward drifts AF23 and AF24 whose inclination angle with respect to the main streamline CL22 is smaller than that of the entrance ceiling surface 342 are as much as possible. Is increasing. As a result, it is possible to suppress the occurrence of turbulence such as vortex in the air flow due to the downwardly-biased air flowing from the passage inlet 33 toward the inlet ceiling surface 342 side being separated from the inlet ceiling surface 342.

On the other hand, for example, in a configuration in which the inclination angle θ22 of the inlet ceiling surface 342 with respect to the mainstream direction is smaller than 10 degrees, the inclination angle of the downward bias flow that advances from the housing proximal end side to the housing distal end side around the housing 21 is small. , The inclination angle θ22 tends to be larger. Therefore, there is a concern that downward biased air or the like flowing from the passage entrance 33 toward the entrance ceiling surface 342 may be separated from the entrance ceiling surface 342 to cause turbulence such as swirl in the airflow.

According to this embodiment, the mainstream direction in which the mainstream line CL22 extends is the direction in which the angle setting surface 27a of the housing 21 extends. Therefore, when the mounting angle of the housing 21 with respect to the piping unit 14 is set, the angle setting surface 27a is used to mount the housing 21 on the piping unit 14 in an appropriate direction according to the circumferential flow direction of the intake passage 12. You can That is, the housing 21 can be attached to the piping unit 14 in a direction in which the entrance ceiling surface 342 can exert the peeling suppression effect.

According to this embodiment, the cross-sectional area S21 of the inlet passage 331 is gradually reduced from the passage inlet 33 toward the passage outlet 34. In this configuration, as the air flowing from the passage inlet 33 to the passage passage 331 advances toward the passage outlet 34, the degree of throttling of the passage passage 331 increases, so that the air is easily rectified by the inner surface of the housing 21. For this reason, the air such as the upwardly-displaced AF25 whose direction of travel has been changed by the entrance ceiling surface 342 is more likely to travel toward the entrance floor surface 346 without spreading to the front surface of the housing or the back side of the housing than the entrance floor surface 346. Air turbulence near the surface 346 can be suppressed. In this way, the entrance passage 331 can be shaped so that the effect of suppressing the separation of the entrance ceiling surface 342 can be easily exerted.

According to the present embodiment, the inclination angle θ25 of the branch measurement line CL23 with respect to the entrance passage line CL24 is 90 degrees or more. In this configuration, the air flowing from the passage entrance 33 into the entrance passage 331 and flowing along the entrance passage line CL24 is allowed to change gently in an obtuse angle without changing the direction of advance sharply in an acute angle. Thus, it can flow into the measurement flow channel 32 from the inlet passage 331. Therefore, when the air flowing through the passage channel 31 flows into the measurement channel 32, it is possible to suppress the occurrence of turbulence of the air flow due to a rapid change in the traveling direction.

According to the present embodiment, the inclination angle θ26 of the branch measurement line CL23 with respect to the main streamline CL22 is 60 degrees or less. In this configuration, since the branch angle of the measurement flow path 32 with respect to the passage flow path 31 is 60 degrees or less, the direction in which the air flowing from the passage inlet 33 into the inlet passage 331 is not suddenly changed, It can flow into the measurement flow path 32 from the inlet passage 331. Therefore, turbulence of the airflow is less likely to occur when the air flowing through the passage channel 31 flows into the measurement channel 32.

Further, in this configuration, in order for the backflow flowing from the passage outlet 34 to flow into the branch measurement passage 351 from the passage passage 31, it is necessary to sharply turn sharply. For this reason, the phenomenon that the backflow is difficult to flow into the branch measurement path 351 is likely to occur, and the backflow can be suppressed from reaching the flow rate sensor 22. In this case, although the backflow that has flowed in from the passage outlet 34 actually reaches the flow rate sensor 22, the airflow meter 20 measures the flow rate because the forward flow that has flowed in from the passage inlet 33 has reached the flow rate sensor 22. It is less likely that it will end up. Therefore, the accuracy of measuring the flow rate of the intake air by the air flow meter 20 can be improved.

Further, in this configuration, when the forward flow flows from the passage channel 31 into the branch measurement path 351, the direction of the flow of the forward flow may gradually change toward the branch measurement path 351. In this case, the backflow is less likely to flow into the branch measurement path 351 as described above, while the forward flow is more likely to flow into the branch measurement path 351. In this way, it is possible to prevent the flow velocity of the forward flow flowing into the measurement flow path 32 from being insufficient, so that it is possible to improve the detection accuracy of the flow rate of the forward flow that has flowed in from the passage inlet 33 by the flow rate sensor 22.

According to the present embodiment, since the opening area of the passage outlet 34 is smaller than the opening area of the passage inlet 33, it is difficult for the backflow generated in the intake passage 12 to flow into the passage outlet 34. Therefore, it is possible to more reliably suppress the backflow from flowing into the branch measurement path 351.

(Other embodiments)
Although a plurality of embodiments according to the present disclosure have been described above, the present disclosure should not be construed as being limited to the above embodiments, and is applied to various embodiments and combinations without departing from the gist of the present disclosure. can do.

<Modification of Configuration Group A>
As a modified example A1, the front top portion 111a and the back top portion 112a in the measurement flow channel 32 do not have to be arranged in the width direction X. For example, of the tops 111a and 112a, only the front top 111a may be arranged on the center line CL5 of the heating resistor 71. In this case, the back top portion 112a is arranged at a position displaced in at least one of the height direction Y and the depth direction Z with respect to the center line CL5.

As a modified example A2, the front top portion 111a of the front narrowed portion 111 may not be arranged on the center line CL5 of the heating resistor 71. For example, the top portion 111 a may be aligned with a part of the heating resistor 71 in the width direction X and may face a part of the heating resistor 71. Further, it is sufficient that the front surface 111 a is aligned with a part of the membrane 62 in the width direction X and faces the part of the membrane 62. Further, it is sufficient that the front surface 111 a is aligned with a part of the flow sensor 22 in the width direction X and faces a part of the flow sensor 22.

As a modified example A3, throttle portions such as the front throttle portion 111 and the back throttle portion 112 may be provided on the measurement ceiling surface 102 or the measurement floor surface 101 in the measurement flow channel 32. For example, in the measurement flow path 32, it is sufficient that at least one of the measurement floor surface 101, the measurement ceiling surface 102, the front measurement wall surface 103, and the back measurement wall surface 104 is provided with a throttle portion.

As a modified example A4, a physical quantity sensor that detects a physical quantity different from the flow rate of intake air may be provided in the measurement flow path. As the physical quantity sensor provided in the measurement flow path, in addition to the flow rate sensors 22 and 202, a detection unit that detects temperature, a detection unit that detects humidity, a detection unit that detects pressure, and the like can be given. These detection units may be mounted on the sensors SA50 and 220 as detection units, or may be provided separately from the sensors SA50 and 220.

As a modified example A5, the air flow meters 20 and 200 do not have to include the passage channels 31 and 211. That is, the bypass flow paths 30 and 210 may not be branched. For example, the measurement inlets 35, 215 of the measurement flow paths 32, 212 are provided on the outer surfaces of the housings 21, 201. In this configuration, all the air that has flowed into the housings 21, 201 from the measurement inlets 35, 215 flows out from the measurement outlets 36, 216.

<Modification of Configuration Group B>
As a modified example B1, the housing partition part may be provided on the housing housing surface. For example, in the first embodiment, as shown in FIG. 51, the housing partition 131 is provided on the housing housing surface 136. In this configuration, the housing partition 131 extends toward the SA accommodation surface 146 of the sensor SA50. The center line CL11 of the housing partition 131 extends in a direction intersecting the height direction Y. The housing partition portion 131 does not extend in the directions X and Y orthogonal to the height direction Y, but extends obliquely from the housing housing surface 136 toward the housing base end side. For this reason, the center line CL11 of the housing partition 131 does not intersect the housing housing surface 136 at a right angle but intersects diagonally.

In this modification, the housing partition 131 is provided on the housing housing surface 136. Therefore, by simply pushing the sensor SA50 toward the inner side of the SA accommodation area 150, the tip of the housing partition 131 is deformed so as to be scraped at the projected corner portion of the housing step surface 137 and the housing accommodation surface 136. You can As a result, the housing partition 131 is easily brought into close contact with the housing accommodation surface 136. Note that, in FIG. 51, a portion of the housing partition 131 that is deformed so as to be scraped off by the sensor SA50 is shown by a two-dot chain line.

As a modified example B2, similarly to the first embodiment, the housing partition may be provided on the housing step surface in the second embodiment. For example, as shown in FIG. 52, the housing partition 271 is provided on the housing step surface 277. In this configuration, the first intermediate hole 236a of the first intermediate wall portion 236 is formed by the front end surface of the first intermediate wall portion 236 rather than the front end portion of the housing partition portion 271. Note that, in FIG. 52, a portion of the housing partition portion 271 that is crushed by the sensor SA220 is illustrated by a two-dot chain line.

Further, as shown in FIG. 53, in the base member 291, the base protrusion 271 a is provided on the wall surface of the first base protrusion 295 on the housing base end side. In the cover member 292, the cover protrusion 271b is provided on the surface of the first cover protrusion 297 on the housing base end side.

As a modified example B3, the housing partitioning portion may be provided on the housing flow path surface in the first embodiment as in the second embodiment. For example, the housing partition 131 is provided on the housing flow path surface 135.

As a modified example B4, a unit recess into which the housing partition enters may be provided in the detection unit. For example, as shown in FIG. 54, in the first embodiment, the SA step surface 147 of the sensor SA50 is provided with the SA recess 161 as a unit recess. In this configuration, when the sensor SA50 is attached to the first housing portion 151, the housing partition 131 is inside the SA recess 161. The concave direction of the SA concave portion 161 from the SA step surface 147 is the same as the protruding direction of the housing partition 131 from the housing step surface 137. That is, the center line of the SA recessed portion 161 coincides with the center line CL11 of the housing partition 131.

With this configuration, the housing partition 131 and the inner surface of the SA recess 161 are easily brought into close contact with each other. Specifically, the depth dimension of the SA recessed portion 161 which is the recessed dimension from the SA step surface 147 is smaller than the projecting dimension of the housing partition 131 from the housing step surface 137. In this case, after inserting the sensor SA50 from the housing opening 151a to insert the housing partition 131 into the SA recess 161 and further pressing the sensor SA50, the housing partition 131 comes into contact with the inner surface of the SA recess 161. It deforms so that it collapses. This facilitates the housing partition 131 to closely contact the inner surface of the SA recess 161.

Even if the housing partition 131 is not in contact with the inner surface of the SA recess 161, the gap between the outer surface of the housing partition 131 and the inner surface of the SA recess 161 has a curved shape. It is less likely that air will pass through. Therefore, in manufacturing the second housing part 152, the fact that the molten resin enters the measurement flow path 32 through the gap between the first housing part 151 and the sensor SA50 means that the housing partition part 131 enters the SA recessed part 161. Can be suppressed by being present.

As a modified example B5, the gap between the housing and the detection unit may be partitioned by the unit partition section of the detection unit. For example, as shown in FIG. 55, in the second embodiment, the sensor SA220 as the detection unit has the SA partition section 302 as the unit partition section. The SA partition portion 302 is a convex portion provided on the outer surface of the sensor SA 220, and projects from the sensor SA 220 toward the housing 201. The front end of the SA partition 302 is in contact with the inner surface of the housing 201. The SA partition section 302 partitions the SA accommodation area 290 and the measurement flow path 212 between the outer surface of the sensor SA 220 and the inner surface of the housing 201.

The SA partition section 302 is provided on the SA flow path surface 285 of the sensor SA 220. The SA partition portion 302 is provided in a portion of the SA flow path surface 285 that faces the housing flow path surface 275 of the housing 201, and projects outward toward the housing flow path surface 275 in a direction intersecting the height direction Y. .. The center line CL14 of the SA partition portion 302 extends linearly in the directions X and Z orthogonal to the height direction Y. The SA partition section 302 circles the outer circumference of the sensor SA 220 together with the SA flow path surface 285 in an annular shape. In this case, the SA partition portion 302 has a portion extending in the width direction X and a portion extending in the depth direction Z, and has a substantially rectangular frame shape as a whole.

The SA partition section 302 has a tapered shape like the housing partition section 131 of the first embodiment. In the housing 201, the front end surface of the first intermediate wall portion 236 is a flat surface, and the front end portion of the SA partition portion 302 is in contact with this flat surface.

In the manufacturing process of the air flow meter 200, when the sensor SA220 is assembled to the base member 291, as shown in FIG. 56, the SA partition portion 302 is deformed in the same manner as the base protrusion 271a of the first embodiment is deformed. Specifically, by pushing the sensor SA220 into the base member 291 through the base opening 291a, the tip of the SA partition 302 is crushed or scraped by the first base protrusion 295 of the base member 291. To transform. Further, when the cover member 292 is assembled to the base member 291, the SA partition portion 302 is deformed in the same manner as the cover protrusion 271b of the first embodiment is deformed. Specifically, by pressing the cover member 292 against the sensor SA 220 and the base member 291, the tip portion of the SA partition 302 is crushed and deformed by the first cover protrusion 297 of the cover member 292. In these cases, in the SA partition portion 302, the tip portion that is newly formed by the tip portion being crushed or scraped becomes easy to adhere to the housing flow path surface 275 of the housing 201, and the SA partition portion 302 and The sealability with the housing flow passage surface 275 is improved.

As a modified example B6, in the modified example B5, as shown in FIG. 57, the SA partition portion 302 may be provided on the SA step surface 287 of the sensor SA220. The SA partition portion 302 extends in the height direction Y toward the housing step surface 277. The center line CL4 of the SA partition portion 302 extends in the height direction Y. The SA partition section 302 circles the outer circumference of the sensor SA 220 together with the SA step surface 287 in an annular shape.

In the process of manufacturing the air flow meter 200, when the sensor SA220 is assembled to the base member 291, as shown in FIG. 58, the SA partition portion 302 is formed by the convex portions 295 and 297 of the base member 291 and the cover member 292 as in the modification B5. Is transformed. This makes it easier for the new front end surface of the SA partition portion 302 to come into close contact with the housing flow path surface 275.

As shown in FIG. 58, the SA partition section 302 is provided at a position closer to the SA flow path surface 285 than the SA accommodation surface 286 on the SA step surface 287. In this configuration, the SA partition portion 302 partitions the measurement flow path 212 and the SA accommodation area 290 at a position as close to the measurement flow path 212 as possible, so that the measurement flow path 212 is provided in the gap between the housing 201 and the sensor SA220. The included part can be made as small as possible. Therefore, since the SA partition section 302 is provided at a position as close as possible to the SA flow path surface 285, the detection accuracy of the flow rate sensor 202 can be improved.

As shown in FIGS. 57 and 58, in the configuration in which the SA partition portion 302 provided on the SA step surface 287 is in contact with the housing step surface 277, both the SA step surface 287 and the housing step surface 277 are high. They intersect the direction Y and face each other. Therefore, when the sensor SA220 is inserted into the first intermediate hole 236a of the first intermediate wall portion 236, the SA partition portion 302 is caught by the housing step surface 277. Therefore, the SA partition portion 302 can be brought into close contact with the housing step surface 277 by simply pushing the sensor SA 220 toward the measurement flow path 212 and into the housing 201.

As a modified example B7, a combination of the modified examples B4 and B5 described above may be provided in the housing with a housing recess into which the unit partition enters. For example, as shown in FIG. 59, in the first embodiment, the sensor SA50 as the detection unit has the SA partition 162 as the unit partition, and the housing 21 has the housing recess 163. .. In this configuration, the SA partition portion 162 is a convex portion provided on the outer surface of the sensor SA50 and protrudes from the sensor SA50 toward the housing 21. The SA partition 162 is in a state of entering the inside of the housing recess 163.

The SA partition 162 is provided on the SA step surface 147 of the sensor SA50. The SA partition 162 extends in the height direction Y, and the center line CL13 of the SA partition 162 extends linearly in a state of being inclined with respect to both the SA step surface 147 and the housing step surface 137. The SA partition 162 circles the outer circumference of the sensor SA50 together with the SA step surface 147 in an annular shape. In this case, the SA partition 162 has a portion extending in the width direction X and a portion extending in the depth direction Z, and has a substantially rectangular frame shape as a whole. The SA partition part 162 has a tapered shape like the housing partition part 131 of the first embodiment.

The housing recess 163 is provided on the housing step surface 137. The recessed direction of the housing recess 163 from the housing step surface 137 is the same as the protruding direction of the SA partition 162 from the SA step surface 147. That is, the center line of the housing recess 163 coincides with the center line CL13 of the SA partition 162.

The SA partition 162 is inserted into the housing recess 163. With this configuration, the SA partition 162 and the inner surface of the housing recess 163 are easily brought into close contact with each other. Specifically, the depth dimension of the housing recess 163 is smaller than the projection dimension of the SA partition 162. In this case, the sensor SA50 is inserted through the housing opening 151a, the SA partition 162 is inserted into the housing recess 163, and then the sensor SA50 is further pressed so that the SA partition 162 contacts the inner surface of the housing recess 163. It deforms so that it collapses. This facilitates the SA partition 162 to closely contact the inner surface of the housing recess 163. Even if the SA partition 162 is not in contact with the inner surface of the housing recess 163, the clearance between the outer surface of the SA partition 162 and the housing recess 163 has a curved shape. Is less likely to pass.

In FIG. 59, of the angles between the center line CL13 of the SA partition 162 and the housing step surface 137, the housing side angle θ14 facing the SA housing area 150 is smaller than the channel side angle θ13 facing the measurement channel 32. Is also getting bigger. That is, the relationship of θ14>θ13 is established. With this configuration, when the front end of the SA partition 162 contacts the housing step surface 137, the front end of the SA partition 162 falls or collapses toward the SA accommodation area 150 side rather than the measurement flow channel 32 side. It's getting easier. Therefore, even if the SA partition 162 is crushed by the housing step surface 137 and crushed scraps such as fragments are generated, the crushed scraps are less likely to enter the measurement flow path 32.

As shown in FIG. 59, in the configuration in which the SA partition 162 provided on the SA step surface 147 is in contact with the housing step surface 137, both the SA step surface 147 and the housing step surface 137 intersect in the height direction Y. And are opposite each other. Therefore, when the sensor SA50 is inserted into the first housing part 151, the SA partition part 162 is caught by the housing step surface 137. In this case, the SA partition part 162 can be brought into close contact with the housing step surface 137 by simply pushing the sensor SA50 toward the measurement flow path 32 and into the first housing part 151.

As a modified example B8, the installation position of the housing partition provided on the housing step surface may not be closer to the housing flow path surface than the housing accommodation surface. For example, in the second embodiment, the housing partition 271 is provided at a position closer to the housing housing surface 276 than the housing flow path surface 275 on the housing step surface 277. In the housing step surface 137, the distance to the housing partition 131 may be the same between the housing flow path surface 135 and the housing housing surface 136.

As a modified example B9, the installation position of the unit partition provided on the unit step surface may not be closer to the unit channel surface than the unit accommodation surface. For example, in the modified example B6, the SA partition portion 302 is provided on the SA step surface 287 at a position closer to the SA housing surface 286 than the SA flow path surface 285. Further, in the SA step surface 287, the separation distance to the SA partition portion 302 may be the same between the SA flow path surface 285 and the SA accommodation surface 286.

As a modified example B10, the housing partition portion may be provided on a plurality of surfaces of the housing step surface, the housing flow path surface, and the housing accommodation surface. In this configuration, the housing partition portions provided on each of the plurality of surfaces may be connected to each other or may be independent of each other. For example, in the first embodiment described above, the housing partition portions 131 provided on the housing step surface 137 and the housing flow path surface 135 are arranged in the height direction Y independently of each other.

As a modified example B11, the unit partition may be provided on a plurality of surfaces among the unit step surface, the unit flow path surface, and the unit housing surface. In this configuration, the unit partition portions provided on each of the plurality of surfaces may be connected to each other or may be independent of each other. For example, in the modified example B7, the SA partition portions 162 provided on the SA step surface 147 and the SA flow path surface 145 are arranged in the height direction Y independently of each other.

As a modified example B12, the housing partition and the unit partition do not have to make a circle around the detection unit. For example, in the housing step surface 137 of the first embodiment, a portion having a high height position in the height direction Y and a portion having a low height position are arranged in the circumferential direction. In this configuration, the housing partition 131 is provided only in the lower part of the higher part and the lower part. In this case, since the high portion of the housing step surface 137 and the housing partition 131 are in contact with the SA step surface 147, no gap is generated between the inner surface of the first housing part 151 and the sensor SA50. Has become. The housing partition 131 does not have an annular shape even if it extends in the width direction X and the depth direction Z.

As a modification B13, the physical quantity measuring device may have both a housing partition and a unit partition. For example, the housing partition section and the unit partition section are arranged in the height direction Y. In this configuration, the unit partition may be provided on a surface of the housing step surface, the housing flow surface, and the housing housing surface that does not face the surface provided with the housing partition, and the unit partition may be provided on the facing surface. It may be provided. The housing partition and the unit partition may be in contact with each other. With this configuration, the housing partition and the unit partition are pressed against each other as the detection unit is inserted into the housing, so that at least one of the housing partition and the unit partition is easily deformed. In this case, since the housing partition and the unit partition easily come into close contact with each other, the sealing property at the boundary between the measurement flow path and the accommodation area is improved by both the housing partition and the unit partition.

As a modified example B14, the shape of the housing partition does not need to change before and after the detection unit is attached to the housing as long as it is in contact with the outer surface of the detection unit. Similarly, the shape of the unit partition does not need to change before and after the detection unit is attached to the housing as long as it is in contact with the inner surface of the housing.

As Modification B15, the direction in which the housing partition portion extends from the inner surface of the housing is not limited to the above-described embodiments. For example, in the first embodiment, the accommodation side angle θ12 may not be larger than the flow path side angle θ11. Similarly, the direction in which the unit partition portion extends from the outer surface of the detection unit is not limited to the above-described embodiments. For example, in the modification B7, the accommodation side angle θ14 may not be larger than the flow path side angle θ11.

As a modification B16, the housing partition and the unit partition do not have to have a tapered shape. For example, in the first embodiment, the housing partition 131 may have a rectangular vertical cross section. In this case, the width dimension of the housing partition 131 in the directions X and Z orthogonal to the height direction Y is the same at the base end and the tip of the housing partition 131.

As a modification B17, the accommodation area may be a space in which a gas such as air exists inside the housing. In this configuration, the sealability at the boundary between the accommodation area and the measurement flow path is improved by the housing partition and the unit partition, so that air can be prevented from flowing back and forth between the accommodation area and the measurement flow path. It For this reason, the accuracy of flow rate detection by the flow rate sensor in the measurement flow channel decreases due to air leaking from the measurement flow channel to the storage region and air entering the measurement flow channel from the storage region. Can be suppressed.

<Modification of Configuration Group C>
As a modification C1, the entrance floor surface may not face the passage entrance side. For example, in the third embodiment described above, as shown in FIG. 60, the inlet floor surface 346 faces the passage outlet 34 side. In this configuration, the inlet floor surface 346 is inclined with respect to the main streamline CL22, the outlet floor surface 347, and the branch floor surface 348 so as to face the side opposite to the passage inlet 33 in the depth direction Z. Further, the entrance floor surface 346 may extend parallel to the main streamline CL22, as shown in FIG. Further, the entire passage floor surface 345 may face the passage outlet 34 side and may extend in parallel with the main streamline CL22 as shown in FIG. 61. In either configuration, the entrance ceiling surface 342 may be inclined with respect to the entrance floor surface 346.

As a modified example C2, the measurement inlet may not face the passage outlet side. For example, in the third embodiment, as shown in FIG. 61, the measurement inlet 35 does not face either the passage inlet 33 side or the passage outlet 34 side. The measurement inlet 35 extends parallel to the main streamline CL22 and faces the passing floor surface 345 side. In this configuration, the passing floor surface 345 extends in parallel with the main streamline CL22, while the outlet ceiling surface 343 is inclined with respect to the main streamline CL22. The exit ceiling surface 343 is inclined with respect to the exit floor surface 347 so as to face the passage exit 34 side.

As a modified example C3, a part of the entrance ceiling surface may be an inclined ceiling surface. For example, in the third embodiment described above, as shown in FIG. 62, the entrance ceiling surface 342 has a ceiling inclined surface 342a and a ceiling connecting surface 342b. In this configuration, the ceiling sloped surface 342 a extends from the passage entrance 33 toward the passage exit 34 and is inclined with respect to the entrance floor surface 346. The ceiling inclined surface 342a faces the passage entrance 33 side, and is inclined with respect to the main streamline CL22 in addition to the entrance floor surface 346. In the depth direction Z, the length dimension of the inclined ceiling surface 342a is smaller than the length dimension of the entrance floor surface 346. The ceiling connecting surface 342b connects the downstream end of the ceiling inclined surface 342a and the upstream end of the measurement inlet 35 in the depth direction Z, and extends parallel to the main streamline CL22 extending in the mainstream direction. In the depth direction Z, for example, the length dimension of the ceiling inclined surface 342a is larger than the length dimension of the ceiling connecting surface 342b.

In this modified example, the ceiling inclined surface 342a is a portion corresponding to the entrance ceiling surface 342 of the third embodiment. Therefore, the inclination angle of the ceiling inclined surface 342a with respect to the entrance floor surface 346 is the inclination angle θ21, and the inclination angle of the ceiling inclined surface 342a with respect to the main streamline CL22 is the inclination angle θ22. Further, in the height direction Y, the separation distance between the ceiling inclined surface 342a and the entrance floor surface 346 is the separation distance H21.

As a modified example C4, in the third embodiment, the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346 may be a value equal to or less than the inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22. For example, as in the modification C1, the inlet floor surface 346 is inclined with respect to the main streamline CL22 so as to face the passage outlet 34 side.

As a modified example C5, in the third embodiment, if the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346 is a value of 10 degrees or more, the inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22 is 10 degrees. The value does not have to be the above value. For example, the entrance ceiling surface 342 is configured to face the passage exit 34. In this configuration, the inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22 is smaller than 0 degrees, while the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346 is 10 degrees or more. .. In this case, the entrance floor surface 346 is largely inclined with respect to the main streamline CL22 so as to face the passage entrance 33 side.

As a modified example C6, in the third embodiment, the inclination angle θ23 of the branch measurement line CL23 with respect to the entrance floor surface 346 may be a value equal to or greater than the inclination angle θ24 of the branch measurement line CL23 with respect to the main streamline CL22. For example, similarly to the modification C4, the inlet floor surface 346 is inclined with respect to the main streamline CL22 so as to face the passage outlet 34 side.

As a modified example C7, in the third embodiment, the inclination angle θ21 of the entrance ceiling surface 342 with respect to the entrance floor surface 346 may be a value in a range larger than 0 degrees and smaller than 10 degrees. Further, the inclination angle θ22 of the entrance ceiling surface 342 with respect to the main streamline CL22 may be a value in a range larger than 0 degrees and smaller than 10 degrees.

As a modified example C8, in the third embodiment described above, the inclination angle θ23 of the branch measurement line CL23 with respect to the entrance floor surface 346 may be a value in a range larger than 0 degrees and smaller than 90 degrees. Further, the inclination angle θ24 of the branch measurement line CL23 with respect to the main streamline CL22 may be a value in a range larger than 0 degrees and smaller than 90 degrees.

As a modified example C9, in the third embodiment, the inlet ceiling surface 342 and the inlet floor surface 346 may be curved so as to bulge or be recessed toward the housing front end side. In this configuration, for example, a straight imaginary line passing through the upstream end portion and the downstream end portion of the entrance ceiling surface 342 is assumed, and the inclination manner of this imaginary line with respect to the entrance floor surface 346 and the main streamline CL22 is set to the entrance ceiling surface 342. The inclination mode is. Further, assuming a straight virtual line passing through the upstream end portion and the downstream end portion of the entrance floor surface 346, the inclination mode of this virtual line with respect to the entrance ceiling surface 342 and the branch measurement line CL23 is the inclination mode of the entrance floor surface 346. And

As a modified example C10, in the third embodiment, the passage passage 31 need not have the outlet passage 332 as long as it has the inlet passage 331 and the branch passage 333. In this configuration, the downstream end of the branch passage 333 serves as the passage outlet 34. Further, in this configuration, the passing ceiling surface 341 has the entrance ceiling surface 342, but does not have the exit ceiling surface 343. Further, in this configuration, the passing floor surface 345 has the entrance floor surface 346 and the branch floor surface 348, but does not have the exit floor surface 347.

As a modified example C11, in the third embodiment, the reduction rate of the cross-sectional area S21 of the inlet passage 331 does not have to be a constant value between the upstream end portion and the downstream end portion of the inlet passage 331. For example, the reduction rate of the cross-sectional area S21 is gradually reduced from the passage inlet 33 toward the passage outlet 34. In this configuration, the graph showing the value of the cross-sectional area S21 in the inlet passage 331 has a shape that bulges downward unlike in FIG. Further, the reduction rate of the cross-sectional area S21 gradually increases from the passage inlet 33 toward the passage outlet 34. With this configuration, the graph showing the value of the cross-sectional area S21 in the inlet passage 331 has a shape that bulges upward, unlike FIG. 42.

As a modified example C12, in the third embodiment, the cross-sectional area S21 of the inlet passage 331 is not the cross-sectional area in the direction orthogonal to the main streamline CL22, but the cross-sectional area in the direction orthogonal to the inlet passline CL24. May be.

As a modified example C13, in the third embodiment, the branch measurement path 351 may be curved without extending straight from the measurement inlet 35. That is, the center line of the branch measurement path 351 may be curved without extending straight. Regarding the configuration in which the center line of the branch measurement path 351 is curved, a tangent line at the measurement inlet 35 is assumed with respect to the center line of the branch measurement path 351 and this tangent line is defined as the branch measurement line CL23.

As a modified example C14, in the third embodiment, the inclination angle θ26 of the branch measurement line CL23 with respect to the exit passage line CL25 may be a value in a range larger than 0 degrees and smaller than 60 degrees.

As a modification C15, in the measurement flow path 32, the flow rate sensor 22 may be provided in the branch measurement path 351, the guide measurement path 352, and the discharge measurement path 354.

As a modified example C16, in the air flow meter 20, the portion having the angle setting surface 27a for setting the installation angle of the housing 21 with respect to the intake passage 12 may not be the flange portion 27. For example, the housing 21 is fixed to the pipe flange 14c with bolts or the like in a state in which a part of the housing 21 is hooked on the tip surface of the pipe flange 14c of the piping unit 14. In this configuration, the surface of the housing 21 that overlaps the tip surface of the pipe flange 14c is the angle setting surface, and the angle setting surface overlaps the tip surface of the pipe flange 14c, so that the housing for the intake passage 12 is formed. 21 installation angles are set.

<Modification of Configuration Group D>
As a modified example D1, the downstream outer curved surface 421 may have a curved portion. For example, as shown in FIG. 63, the downstream outer curved surface 421 has a downstream outer curved surface 461 in addition to the downstream outer lateral surface 422 and the downstream outer vertical surface 423. The downstream outer curved surface 461 extends so as to bulge along the center line CL4 of the measurement flow path 32, and is curved so as to continuously bend along the center line CL4. The downstream outer curved surface 461 is provided between the downstream outer lateral surface 422 and the downstream outer vertical surface 423 in the direction in which the center line CL4 extends, and connects the downstream outer lateral surface 422 and the downstream outer vertical surface 423. ing.

The radius of curvature R34 of the downstream outer curved surface 461 is smaller than the radius of curvature R33 of the upstream outer curved surface 411. Therefore, similarly to the first embodiment, the downstream outer curved surface 421 is bent more tightly than the upstream outer curved surface 411. On the other hand, the radius of curvature R34 of the downstream outer curved surface 461 is larger than the radius of curvature R32 of the downstream inner curved surface 425. Therefore, the bend of the downstream outer curved surface 421 is looser than the bend of the downstream inner curved surface 425.

The line CL31 passes through the downstream outer curved surface 421 instead of the downstream outer vertical surface 423 in the downstream outer curved surface 421. In this configuration, the air that has passed through the flow rate sensor 22 and traveled along the line CL31 changes its direction by hitting the downstream outer curved surface 461, and thus it becomes easier to travel toward the downstream side of the downstream curved path 407.

According to this modification, since the downstream outer curved surface 421 has the downstream outer curved surface 461, the air blown out from between the sensor support portion 51 and the throttle portions 111 and 112 toward the downstream curved passage 407. Becomes easier to flow along the downstream curved surface 461. In this case, the air that has passed through the flow rate sensor 22 is less likely to stay in the downstream curved path 407, so that it is possible to prevent the flow rate and flow velocity of the air that passes through the flow rate sensor 22 from decreasing.

Further, since the radius of curvature R34 of the downstream outer curved surface 461 is smaller than the radius of curvature R33 of the upstream outer curved surface 411, the degree of depression of the downstream outer curved surface 421 is larger than the degree of depression of the upstream outer curved surface 411. It is preferable. In this configuration, while the degree of depression of the downstream curved outer surface 421 is maximized, the air reaching the downstream curved passage 407 from the flow sensor 22 side easily flows toward the measurement outlet 36 along the downstream curved outer surface 461. Therefore, the shape of the downstream outer curved surface 421 can suppress that the air stays in the downstream curved path 407 and the pressure loss in the downstream curved path 407 increases.

As the modified example D2, in the modified example D1, the downstream outer curved surface 421 has the downstream outer curved surface 461, but does not have at least one of the downstream outer lateral surface 422 and the downstream outer vertical surface 423. May be. For example, the downstream outer curved surface 421 does not have both the downstream outer lateral surface 422 and the downstream outer vertical surface 423. In this configuration, the downstream outer curved surface 461 is bridged between the upstream end portion and the downstream end portion of the downstream curved path 407. In this case, the entire downstream outer curved surface 421 is the downstream outer curved surface 461, and the downstream outer curved surface 421 corresponds to the downstream outer curved surface.

As a modified example D3, the upstream curved outer surface 411 includes an upstream outer longitudinal surface that extends straight from the upstream end of the upstream curved passage 406, an upstream outer lateral surface that extends straight from the downstream end of the upstream curved passage 406, You may have at least one of these. In this configuration, the entire upstream outer curved surface 411 is not the upstream outer curved surface, but the upstream outer curved surface 411 is not only the upstream outer vertical surface and the upstream outer lateral surface but also the upstream outer curved surface. Will have a face. For example, in a configuration in which the upstream outer curved surface 411 has an upstream outer vertical surface and an upstream outer curved surface, the line CL31 may pass through the upstream outer vertical surface. Further, in the upstream outer curved surface 411, an upstream outer corner portion may be formed as an inner corner portion in which the upstream outer vertical surface and the upstream outer lateral surface are inwardly interdigitated with each other.

As a modified example D4, the upstream inner curved surface 415 has an upstream inner vertical surface that extends straight from the upstream end portion of the upstream curved passage 406, and an upstream inner lateral surface that extends straight from the downstream end portion of the upstream curved passage 406. You may have at least one of these. In this configuration, the entire upstream inner curved surface 415 is not the upstream inner curved surface, but the upstream inner curved surface 415 has at least one of the upstream inner vertical surface and the upstream inner lateral surface, and the upstream inner curved surface. Will have. Further, in the upstream inward curved surface 415, an upstream inward corner portion may be formed as an outward corner portion where the upstream inner vertical surface and the upstream inner lateral surface face outward.

As a modified example D5, the downstream inner curved surface 425 includes a downstream inner vertical surface that extends straight from the upstream end portion of the downstream curved passage 407, and a downstream inner lateral surface that extends straight from the downstream end portion of the downstream curved passage 407. You may have at least one of these. In this configuration, the entire downstream inner curved surface 425 is not a downstream inner curved surface, and the downstream inner curved surface 425 has at least one of the downstream inner vertical surface and the downstream inner lateral surface, and further has the downstream inner curved surface. Will have. In the downstream inward curved surface 425, a downstream inward corner may be formed as an outward corner in which the downstream inner vertical surface and the downstream inner lateral surface face outward.

As a modified example D6, the outer curved surfaces 411, 421 and the inner curved surfaces 415, 425 have at least one inclined surface inclined with respect to the alignment line CL31, and thus are curved not stepwise but stepwise. May be. For example, the downstream outer curved surface 421 has a downstream outer inclined surface as an inclined surface that extends straight in a direction inclined with respect to the line CL31. In this configuration, the connecting portion between the downstream outer lateral surface 422 and the downstream outer vertical surface 423 is chamfered by the downstream outer inclined surface, and the downstream outer curved surface 421 has the downstream outer entry corner portion 424. Absent. Further, a plurality of downstream outer inclined surfaces may be arranged along the center line CL4 of the measurement flow path 32, and in this configuration, the downstream outer curved surface 421 has a shape curved stepwise by the plurality of downstream outer inclined surfaces. Become.

As a modification D7, a configuration in which the degree of depression of the downstream outer curved surface 421 is larger than the degree of depression of the upstream outer curved surface 411 may be realized regardless of the radius of curvature. For example, the entire downstream outer curved surface 421 is the downstream outer curved surface, the entire upstream outer curved surface 411 is the upstream outer curved surface, and the radius of curvature R34 of the downstream outer curved surface 421 is greater than the radius of curvature R33 of the upstream outer curved surface 411. Also assume a large configuration. Also in this configuration, if the length dimension of the downstream outer curved surface 421 is smaller than the length dimension of the upstream outer curved surface 411 in the direction in which the center line CL4 of the measurement flow channel 32 extends, the degree of depression of the downstream outer curved surface 421 is It is larger than the degree of depression of the upstream outer curved surface 411.

As a modified example D8, in the sensor path 405, it is sufficient that at least the measurement floor surface 101 extends straight along the line CL31. Further, the upstream end of the flow rate sensor 22 may be provided at the upstream end of the sensor path 405, and the downstream end of the flow rate sensor 22 may be provided at the downstream end of the sensor path 405. For example, the length dimension of the sensor path 405 and the length dimension of the flow rate sensor 22 may be the same in the depth direction Z.

As a modified example D9, in the depth direction Z, the downstream end of the upstream outer curved surface 411 may be provided at a position closer to the flow rate sensor 22 than the downstream end of the upstream inner curved surface 415. In this case, the upstream end of the sensor path 405 is defined by the downstream end of the upstream outer curved surface 411, not by the downstream end of the upstream inner curved surface 415. Further, in the depth direction Z, the upstream end of the downstream outer curved surface 421 may be provided at a position closer to the flow rate sensor 22 than the upstream end of the downstream inner curved surface 425. In this case, the downstream end of the sensor path 405 is defined not by the upstream end of the downstream inner curved surface 425 but by the upstream end of the downstream outer curved surface 421.

As a modified example D10, the line CL31 may pass through the flow rate sensor 22. The line CL31 does not have to be the center CO1 of the heating resistor 71, for example, as long as it passes through a part of the heating resistor 71. Further, the line CL31 may pass through the center or a part of the membrane portion 62, or may pass through the center or a part of the flow rate sensor 22. Further, the line CL31 may be inclined with respect to the angle setting surface 27a of the housing 21, the depth direction Z, and the mainstream direction as long as the line CL31 extends in the direction in which the upstream curved line 406 and the downstream curved line 407 are arranged. ..

As a modified example D11, on the line CL31, if the flow rate sensor 22 is arranged at a position closer to the upstream outer curved surface 411 than the downstream outer curved surface 421, the sensor support portion 51 is located upstream of the downstream outer curved surface 421. It may not be arranged at a position close to the outer curved surface 411. In this case, in the sensor support portion 51, on the line CL31, the flow rate sensor 22 is arranged at a position closer to the mold upstream surface 55c than the mold downstream surface 55d.

As a modified example D12, on the line CL31, if the flow rate sensor 22 is arranged at a position closer to the upstream outer curved surface 411 than the downstream outer curved surface 421, the upstream end portion of the sensor path 405 than the downstream end portion thereof. It does not have to be arranged at a position close to. In this case, on the line CL31, the distance between the upstream end of the downstream curved path 407 and the downstream outer curved surface 421 is larger than the distance between the downstream end of the upstream curved path 406 and the upstream outer curved surface 411. Has become.

As a modified example D13, in the measurement flow path 32, the upstream curved path 406 and the downstream curved path 407 may be curved in opposite directions with respect to the sensor path 405. For example, both the upstream curved path 406 and the downstream curved path 407 do not extend from the sensor path 405 toward the housing front end side, but one extends toward the housing front end side and the other extends toward the housing base end side. The configuration. If the upstream curved path 406 extends from the sensor path 405 toward the housing front end side, and the downstream curved path 407 extends from the sensor path 405 toward the housing proximal end side, the downstream outer curved surface 421 becomes the measurement floor surface. It extends from the measurement ceiling surface 102 instead of 101. Further, the downstream curved surface 425 extends from the measurement floor surface 101 instead of the measurement ceiling surface 102.

As a modified example D14, the measurement diaphragm surface and the measurement expansion surface of the measurement diaphragm unit may be curved so as to be concave, or may be straight without being curved. For example, as shown in FIG. 64, in the throttle portions 111 and 112, the throttle surfaces 431 and 441 extend straight from the tops 111a and 112a toward the upstream side, and the expansion surfaces 432 and 442 extend from the tops 111a and 112a to the downstream side. The structure extends straight toward the user. The throttle surfaces 431 and 441 are inclined with respect to the line CL31 so as to face the upstream side of the measurement flow channel 32, and the expansion surfaces 432 and 442 have the line CL31 so as to face the downstream side of the measurement flow channel 32. Is inclined to. The increase rate of the protrusion size of the diaphragm surfaces 431 and 441 is uniform from the diaphragm upstream surfaces 433 and 443 to the tops 111a and 112a. Further, the reduction rate of the protrusion dimension of the expansion surfaces 432, 442 is uniform from the tops 111a, 112a to the expansion downstream surfaces 434, 444.

The narrowed portions 111 and 112 have front end surfaces extending along the line CL1, and the front end surfaces are top portions 111a and 112a. The centers of the tops 111a and 112a in the depth direction Z are arranged at positions closer to the downstream curved path 407 than the center line CL5 of the heating resistor 71.

According to this modification, since the front diaphragm surface 431 and the back diaphragm surface 441 extend straight, it is possible to enhance the air flow rectifying effect by these diaphragm surfaces 431 and 441. Further, since the front expansion surface 432 and the back expansion surface 442 extend straight, the airflow is disturbed by the separation of the airflow from the expansion surfaces 432 and 442 to the extent that the detection accuracy of the flow rate sensor 22 is not deteriorated. It's getting easier. In this case, the momentum of the air blown as a jet stream toward the downstream curved path 407 from between the sensor support portion 51 and the expansion surfaces 432 and 442 can be weakened. Therefore, it is possible to prevent the jet flow from bouncing back on the downstream curved surface 421 and returning to the flow rate sensor 22 as a back flow.

In the measurement diaphragm unit, only one of the measurement diaphragm surface and the measurement expansion surface may extend straight. Specifically, at least one of the front diaphragm surface 431, the front expansion surface 432, the back diaphragm surface 441, and the back expansion surface 442 may extend straight. Further, the front top portion 111a and the back top portion 112a may be curved so as to bulge or may be curved so as to be recessed.

As a modified example D15, the shapes and sizes of the narrowed portions 111 and 112 may be different from the configuration of the first embodiment. For example, in the throttle portions 111 and 112, the length dimensions W32a and W32b of the throttle surfaces 431 and 441 may not be smaller than the length dimensions W33a and W33b of the expansion surfaces 432 and 442. Further, the front restriction upstream surface 433 and the front expansion downstream surface 434 may not be flush with each other. In this case, the protrusion dimension of the front throttle surface 431 from the front throttle upstream surface 433 is different from the protrusion dimension of the front expansion surface 432 from the front expansion downstream surface 434. Regarding the back drawn portion 112 as well, like the front drawn portion 111, the back drawn upstream surface 443 and the back expanded downstream surface 444 may not be flush with each other. In this case, the projecting size of the back drawn surface 441 from the back drawn upstream surface 443 and the projected size of the back expanded surface 442 from the back expanded downstream surface 444 are different.

As a modified example D16, the front narrowing portion 111 and the back narrowing portion 112 may have different shapes and sizes. For example, the length dimension W31a of the front drawn portion 111 may be larger or smaller than the length dimension W31b of the back drawn portion 112. The length dimension W32a of the front drawing surface 431 may be larger or smaller than the length dimension W32b of the back drawing surface 441. Further, the length dimension W33a of the front expanded surface 432 may be larger or smaller than the length dimension W33b of the back expanded surface 442. The protrusion dimensions D32a and D36a of the front top portion 111a may be the same as or smaller than the protrusion dimensions D32b and D36b of the back top portion 112a.

As a modified example D17, the narrowed portions 111 and 112 may extend outside the measurement partitioning portion 451 in the depth direction Z. Further, the narrowed portions 111 and 112 may be provided at positions that do not enter the inside of the upstream curved path 406 and the downstream curved path 407. For example, the throttle portions 111 and 112 are provided only on the sensor path 405 among the sensor path 405, the upstream curved path 406, and the downstream curved path 407. Furthermore, the diaphragm units 111 and 112 do not have to span the measurement ceiling surface 102 and the measurement floor surface 101. For example, the narrowed portions 111 and 112 are configured to extend from only one of the measurement ceiling surface 102 and the measurement floor surface 101. Further, the diaphragm portions 111 and 112 are provided between the measurement ceiling surface 102 and the measurement floor surface 101 at positions apart from both the measurement ceiling surface 102 and the measurement floor surface 101.

As a modified example D18, measurement diaphragms such as diaphragms 111 and 112 are provided on at least one of the front measurement wall surface 103, the back measurement wall surface 104, the outer measurement curved surface 401, and the inner measurement curved surface 402 in the measurement flow path 32. It should be. For example, at least one of the front narrowing portion 111 and the back narrowing portion 112 is provided. In addition, the measurement diaphragm portions are provided on the measurement wall surfaces 103 and 104 and the measurement curved surfaces 401 and 402, respectively.

As a modification D19, the degree of swelling of the downstream inner curved surface 425 does not have to be smaller than the degree of swelling of the upstream inner curved surface 415. Further, the degree of depression of the downstream outer curved surface 421 may be smaller than the degree of swelling of the downstream inner curved surface 425. Further, the degree of depression of the upstream outer curved surface 411 may be larger than the degree of bulge of the upstream inner curved surface 415. In any configuration, it is preferable that the relationship of L35b>L35a is established in the measurement flow channel 32.

As a modified example D20, the relationship of L35b>L35a may not be established in the measurement flow channel 32. That is, the distance L35b between the downstream outer curved surface 421 and the downstream inner curved surface 425 may not be larger than the distance L35a between the upstream outer curved surface 411 and the upstream inner curved surface 415.

As a modified example D21, the degree of depression of the downstream outer curved surface 421 may not be larger than the degree of depression of the upstream outer curved surface 411.

As a modified example D22, the flow rate sensor 22 does not have to be arranged on the line CL31 at a position closer to the upstream outer curved surface 411 than the downstream outer curved surface 421.

<Modification of Configuration Group E>
As a modified example E1, of the mold upstream surface 55c of the sensor support portion 51, the entire portion provided in the measurement flow path 32 may be arranged upstream of the throttle portions 111 and 112. That is, in the measurement flow path 32, if a portion of the mold upstream surface 55c included in the aligned cross section CS41 is provided on the upstream side of the narrowed portions 111 and 112, the other portion is formed from the narrowed portions 111 and 112. Also need not be provided on the upstream side.

As a modified example E2, in the aligned cross-section CS41, the mold upstream surface 55c may be arranged on the upstream side of at least one of the front draw part 111 and the back draw part 112. For example, the back drawn portion 112 is arranged and arranged on the downstream side of the mold upstream surface 55c in the cross section CS41.

As a modified example E3, in the sensor support portion 51, the mold upstream inclined surface 471 may be inclined with respect to the height direction Y so as to gradually approach the mold downstream surface 55d toward the mold base end surface 55b. Further, the mold upstream inclined surface 471 may be a curved surface such as a curved surface that is curved so as to bulge or be recessed in the depth direction Z.

As a modified example E4, the mold upstream surface 55c of the sensor support portion 51 may not have the mold upstream inclined surface 471. For example, the mold upstream surface 55c does not incline with respect to the height direction Y and extends from the mold front end surface 55a toward the mold base end surface 55b.

As a modified example E5, at least a part of the mold upstream surface 55c of the sensor support portion 51 may be provided in the upstream curved path 406. For example, the entire mold upstream inclined surface 471 is provided in the upstream curved path 406. Further, the sensor support portion 51 may be provided at a position separated from the upstream curved path 406.

As a modified example E6, in the mold downstream surface 55d of the sensor support portion 51, the entire portion provided in the measurement flow path 32 is arranged on the upstream side of the downstream end portions 111c and 112c of the throttle portions 111 and 112. Good. That is, in the measurement flow path 32, if the portion of the mold downstream surface 55d included in the aligned cross section CS41 is on the upstream side of the downstream end portions 111c and 112c of the narrowed portions 111 and 112, the other portion is the downstream end portion. It may not be provided on the upstream side of 111c and 112c.

As a modified example E7, in the aligned cross-section CS41, the mold downstream surface 55d may be arranged on the upstream side of at least one of the front downstream end 111c of the front narrowed portion 111 and the back downstream end 112c of the back narrowed portion 112. .. For example, the back downstream end 112c of the back drawn portion 112 is arranged and arranged on the downstream side of the mold downstream surface 55d in the cross section CS41.

As a modification E8, in the sensor support portion 51, the mold downstream inclined surface 472 may be inclined with respect to the height direction Y so as to gradually approach the mold upstream surface 55c toward the mold base end surface 55b. Further, the mold downstream inclined surface 472 may be a curved surface such as a curved surface that is curved so as to bulge or be recessed in the depth direction Z.

As a modified example E9, the mold downstream surface 55d of the sensor support portion 51 may not have the mold downstream inclined surface 472. For example, the mold downstream surface 55d does not incline with respect to the height direction Y and extends from the mold front end surface 55a toward the mold base end surface 55b.

As a modified example E10, at least a part of the mold downstream surface 55d of the sensor support portion 51 may be provided in the downstream curved path 407. For example, the entire mold downstream inclined surface 472 is provided in the downstream curved path 407. Further, the sensor support portion 51 may be provided at a position separated from the downstream curved path 407.

As a modified example E11, of the mold downstream surface 55d of the sensor support portion 51, the entire portion provided in the measurement flow path 32 may be arranged on the downstream side of the throttle portions 111 and 112.

As a modified example E12, the flow rate sensor 22 may be provided on the downstream side or the upstream side of the front top portion 111a or the back top portion 112a at a position where the flow velocity is highest in the measurement flow path 32. In addition, the flow rate sensor 22 may be provided at a position different from the position where the flow velocity is highest in the measurement flow channel 32.

As a modified example E13, the opening area of the measurement outlet 36 does not have to be smaller than the opening area of the measurement inlet 35. Further, the opening area of the passage outlet 34 need not be smaller than the opening area of the passage inlet 33.

<Characteristics of configuration group A>
The features disclosed in the configuration group A are included in the configurations disclosed in this specification as described below.

[Characteristic A1]
A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A measurement channel (32) through which the fluid flows,
A housing (21) forming a measurement flow path,
A physical quantity sensor (22) for detecting the physical quantity of the fluid in the measurement flow path, and a plate-shaped sensor support section (51) for supporting the physical quantity sensor, and a support tip section (55a) that is the tip section of the sensor support section. A detection unit (50) attached to the housing so that the sensor and the physical quantity sensor are housed in the measurement flow path;
Equipped with
The sensor support is
A support surface (55e) which is one plate surface of the sensor support portion and on which a physical quantity sensor is provided;
A support back surface (55f) opposite to the support surface,
Has
The housing is
A floor surface (101) facing the support tip,
A front wall surface (103) facing the support surface,
A back wall surface (104) provided on the opposite side of the front wall surface through the floor surface and facing the support back surface;
Has as a forming surface forming a measurement flow path,
The front distance (L1), which is the distance between the front surface and the rear surface in the front-back direction (X) and the physical quantity sensor, is orthogonal to the front-back direction, and the floor surface and the support tip are aligned. A physical quantity measuring device that is larger than a floor distance (L3), which is the distance between the floor surface and the supporting tip in the height direction (Y).

[Feature A2]
The physical quantity measuring device according to Feature A1, wherein the front distance is smaller than a back distance (L2) that is a distance between the back wall surface and the support back surface in the front and back directions.

[Feature A3]
The housing is
The front wall surface is formed and bulges toward the back wall surface in the front-back direction. The measurement width dimension (W1), which is the distance between the front wall surface and the back wall surface in the front-back direction, gradually increases from the upstream side toward the physical quantity sensor. It has a front throttle part (111) that narrows the measurement flow path so as to be small,
The front distance is the physical quantity measurement device according to Feature A1 or A2, which is the distance between the front diaphragm portion and the physical quantity sensor in the front-back direction.

[Feature A4]
The measurement channel is
A measurement inlet (35) at the upstream end of the measurement flow path, into which the fluid flows,
A measurement outlet (36) at the downstream end of the measurement flow path, through which the fluid flows,
Has
The center line (CL4) of the measurement flow passage extends along the measurement flow passage through the center (CO2) of the measurement inlet and the center (CO3) of the measurement outlet,
The front narrowing portion has a front top portion (111a) that is the top portion having the smallest separation distance (W2) between the front narrowing portion and the center line of the measurement flow path, and the front top portion and the physical quantity sensor face each other in the front-back direction. It is provided in the position to
The physical distance measurement device according to Feature A3, wherein the front distance is a distance between the front top and the physical quantity sensor.

[Feature A5]
The housing is
A back diaphragm part (112) that forms a back wall surface and bulges toward the front wall surface in the front-back direction, and narrows the measurement flow channel so that the measurement width dimension gradually decreases from the upstream side toward the physical quantity sensor. The physical quantity measuring device according to the feature A3 or A4, which has.

[Feature A6]
The measurement channel is
It has a front area (122) which is an area between the front wall surface and the support surface in the front-back direction,
The tablespace is
A floor area (122a) between the physical quantity sensor and the floor surface in the height direction,
A ceiling side area (122b) on the side opposite to the floor side area through the physical quantity sensor in the height direction;
Has
In the cross-sectional area (S1) of the portion where the physical quantity sensor is provided in the measurement flow path,
A floor side area (S2) which is an area of a floor side region,
A ceiling side area (S3) which is an area of a ceiling side region,
Is included,
The physical quantity measuring device according to any one of features A1 to A5, in which the area on the ceiling side is smaller than the area on the floor side.

[Feature A7]
The measurement flow path is curved so that the floor surface is on the inner peripheral side,
In the front area, the physical quantity measuring device according to Feature A6, in which the floor side area is provided on the inner peripheral side of the ceiling side area.

[Feature A8]
The physical quantity sensor is
A heater section (71) that generates heat;
A temperature detection section (72, 73) arranged along the heater section along one surface (65a) of the physical quantity sensor, for detecting the temperature;
Has
The physical distance measuring device according to any one of features A1 to A7, wherein the surface distance is a distance between the surface wall surface and the heater portion.

[Feature A9]
The sensor support is
A sensor board (65) which is a board on which a physical quantity sensor is mounted;
A protective resin portion (55) formed of a resin material and protecting the sensor substrate and the physical quantity sensor;
Has
The physical quantity measuring device according to any one of features A1 to A7, in which the supporting front surface and the supporting back surface are formed of a protective resin portion.

<Characteristics of configuration group B>
The features disclosed in the configuration group B are included in the configurations disclosed in this specification as described below.

[Feature B1]
A physical quantity measuring device (20, 200) for measuring a physical quantity of a fluid,
A measurement flow path (32, 212) through which the fluid flows,
A detection unit (50, 220) having a physical quantity sensor (22, 202) provided in the measurement flow path for detecting the physical quantity of the fluid, and a sensor support portion (51, 221) supporting the physical quantity sensor,
A housing (21, 201) forming a measurement flow path and an accommodation area (150, 290) accommodating a part of the detection unit;
Equipped with
The inner surface of the housing is
A housing intersecting surface (137, 277) intersecting in a direction (Y) in which the measurement flow path and the housing region are arranged side by side;
A housing channel surface (135, 275) extending from the housing intersecting surface toward the measurement channel side;
A housing housing surface (136, 276) extending from the housing intersecting surface toward the housing area side;
Has
The housing is
It is provided on at least one of the housing intersecting surface, the housing flow path surface, and the housing accommodation surface, projects toward the detection unit, and partitions the measurement flow path and the accommodation area between the housing and the detection unit in a state of being in contact with the detection unit. A physical quantity measuring device having a housing partition part (131, 271).

[Feature B2]
The physical quantity measuring device according to Feature B1, wherein the housing partitioning portion makes a circle around the detection unit.

[Feature B3]
The physical quantity measuring device according to feature B1 or B2, wherein the housing partition portion is provided at a position closer to the housing flow path surface than the housing accommodation surface on the housing intersecting surface.

[Feature B4]
At a portion where the center line (CL11) of the housing partition provided on the housing intersecting surface and the housing intersecting surface intersect, the accommodation side angle (θ12) facing the accommodation area is the channel side angle (θ11) facing the measurement channel. The physical quantity measuring device according to any one of the features B1 to B3.

[Feature B5]
The detection unit has a unit recess (161) that is a recess provided in the detection unit,
The physical quantity measuring device as described in any one of the features B1 to B4, wherein the housing partition portion enters the unit recess and is in contact with the inner surface of the unit recess.

[Feature B6]
The outer surface of the detection unit is
Unit intersection planes (147, 287) intersecting in the arrangement direction (Y) in which the measurement channel and the accommodating region are arranged side by side,
A unit channel surface (145, 285) extending from the unit intersection surface toward the measurement channel side;
A unit housing surface (146, 286) extending from the unit intersection surface toward the housing area side;
Has as an outer surface of the detection unit,
The physical quantity measuring device according to any one of the features B1 to B5, wherein the housing partition portion is in contact with at least one of the unit intersecting surface, the unit flow path surface, and the unit housing surface.

[Feature B7]
The physical quantity measuring device according to Feature B6, wherein the housing partition portion is provided on the housing intersecting surface and is in contact with the unit intersecting surface.

[Feature B8]
A physical quantity measuring device (20, 200) for measuring a physical quantity of a fluid,
A measurement flow path (32, 212) through which the fluid flows,
A detection unit (50, 220) having a physical quantity sensor (22, 202) provided in the measurement flow path for detecting the physical quantity of the fluid, and a sensor support portion (51, 221) supporting the physical quantity sensor,
A housing (21, 201) forming a measurement flow path and an accommodation area (150, 290) accommodating a part of the detection unit;
Equipped with
The outer surface of the detection unit is
Unit intersection planes (147, 287) intersecting in the arrangement direction (Y) in which the measurement channel and the accommodating region are arranged side by side,
A unit channel surface (145, 285) extending from the unit intersection surface toward the measurement channel side;
A unit housing surface (146, 286) extending from the unit intersection surface toward the housing area side;
Has
The detection unit is
It is provided on at least one of the unit intersecting surface, the unit flow path surface, and the unit accommodating surface, projects toward the housing, and partitions the measurement flow path and the accommodating region between the housing and the detection unit in a state of being in contact with the housing. A physical quantity measuring device having unit partition parts (162, 302).

[Feature B9]
The physical quantity measuring device according to Feature B8, wherein the unit partitioning portion makes a circle around the detection unit.

[Feature B10]
The physical quantity measuring device according to feature B8 or B9, wherein the unit partition portion is provided at a position closer to the unit flow path surface than the unit housing surface at the unit intersecting surface.

[Feature B11]
At the intersection of the center line (CL13) of the unit partition provided on the unit intersecting surface and the unit intersecting surface, the accommodation side angle (θ14) facing the accommodation area is the channel side angle (θ13) facing the measurement channel. ) Is larger than the above), the physical quantity measuring device according to any one of features B8 to B10.

[Feature B12]
The housing has a housing recess (163) which is a recess provided in the housing,
The physical quantity measuring device according to any one of the features B8 to B11, wherein the unit partition portion enters the housing recess and is in contact with the inner surface of the housing recess.

[Feature B14]
The inner surface of the housing is
A housing intersecting surface (137, 277) intersecting in a direction (Y) in which the measurement flow path and the housing region are arranged side by side;
A housing channel surface (135, 275) extending from the housing intersecting surface toward the measurement channel side;
A housing housing surface (136, 276) extending from the housing intersecting surface toward the housing area side;
Has
The physical quantity measuring device according to any one of features B8 to B13, wherein the unit partition portion is in contact with at least one of the housing intersecting surface, the housing flow path surface, and the housing housing surface.

[Feature B15]
The physical quantity measuring device according to Feature B14, wherein the unit partition is provided on the unit intersecting surface and is in contact with the housing intersecting surface.

<Characteristics of configuration group C>
The features disclosed in the configuration group C are included in the configurations disclosed in this specification as described below.

[Characteristic C1]
A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A passage channel (31) having a passage inlet (33) into which the fluid flows, and a passage outlet (34) from which the fluid introduced from the passage inlet flows out;
A measurement flow path (32) branched from the passage flow path for measuring the physical quantity of the fluid, the measurement flow path being provided between the passage entrance and the passage exit and having the measurement flow inlet (35) into which the fluid flows. A measurement flow path (32) having a measurement outlet (36) through which the fluid flowing from the measurement inlet flows out;
A physical quantity sensor (22) provided in the measurement flow path for detecting the physical quantity of the fluid;
A housing (21) forming a passage and a measurement passage,
Equipped with
The inner surface of the housing is
An inlet passage that forms an inlet passage (331) that extends over the passage inlet and the measurement inlet of the passage passage and that extends over the passage inlet and the measurement inlet in the direction (Z) in which the passage inlet and the passage outlet are aligned. The ceiling surface (342),
An entrance floor surface (346) that forms an entrance passage and faces the entrance ceiling surface through the entrance passage;
Has
The entrance ceiling surface is
The ceiling inclined surface (342, which is inclined with respect to the entrance floor surface so that the distance (H21) from the entrance floor surface gradually decreases from the passage entrance toward the passage exit and extends from the passage entrance toward the measurement entrance (342, 342a) having a physical quantity measuring device.

[Characteristic C2]
The physical quantity measuring device according to Feature C1, wherein the inclination angle (θ21) of the ceiling inclined surface with respect to the entrance floor surface is 10 degrees or more.

[Characteristic C3]
The physical quantity measuring device according to feature C1 or C2, wherein the ceiling inclined surface is inclined with respect to the entrance floor surface so as to face the passage entrance side.

[Characteristic C4]
One of the features C1 to C3, wherein the ceiling inclined surface is inclined so as to face the passage inlet side with respect to the main flow direction (Z), which is the direction in which the main flow of the fluid that mainly flows into the passage inlet advances. The physical quantity measuring device described in.

[Characteristic C5]
The physical quantity measuring device according to Feature C4, wherein the inclination angle (θ22) of the ceiling inclined surface with respect to the mainstream direction is 10 degrees or more.

[Characteristic C6]
The housing is
It has an angle setting surface (27a) for setting the mounting angle of the housing with respect to the mounting target (14) to which the housing is mounted,
The physical quantity measuring device according to feature C4 or C5, in which the mainstream direction is a direction in which the angle setting surface extends.

[Characteristic C7]
The physical quantity measuring device according to any one of features C1 to C6, in which a cross-sectional area (S21) of the entrance passage is gradually reduced from the passage entrance toward the measurement entrance.

[Characteristic C8]
Any one of the features C1 to C7 in which the inclination angle (θ25) of the center line (CL23) of the measurement flow path at the measurement entrance with respect to the entrance passage line (CL24) that is the center line of the entrance passage is 90 degrees or more The physical quantity measuring device described in.

[Characteristic C9]
The physical quantity measuring device according to any one of features C1 to C8, in which a branch angle (θ26) of the measurement flow path with respect to the passage flow path is 60 degrees or less.

<Characteristics of Group D>
The configuration disclosed in this specification includes the features of the configuration group D as described below.

[Feature D1]
A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A measurement flow path (32) having a measurement inlet (35) into which the fluid flows, and a measurement outlet (36) from which the fluid introduced from the measurement inlet flows out;
A physical quantity sensor (22) provided in the measurement flow path for detecting the physical quantity of the fluid;
A housing (21) forming a measurement flow path,
Equipped with
The measurement channel is
A sensor path (405) provided with a physical quantity sensor;
An upstream curved path (406) provided in the measurement flow path between the sensor path and the measurement entrance, and curved in the housing so as to extend from the sensor path toward the measurement entrance;
A downstream curved path (407) provided between the sensor path and the measurement outlet in the measurement flow path, and curved in the housing so as to extend from the sensor path toward the measurement exit;
Has
The inner surface of the housing is
An upstream outer curved surface (411) forming an upstream curved path from the outside of the curve,
A downstream outer curved surface (421) forming a downstream curved path from the outside of the curve;
Has
A physical quantity measuring device in which the degree of depression of the downstream outer curved surface toward the side that expands the measurement flow path is greater than the degree of depression of the upstream outer curved surface toward the side that expands the measurement flow path.

[Feature D2]
The upstream outer curved surface has an upstream outer curved surface (411) curved along the upstream curved path,
The downstream outer curved surface has a downstream outer curved surface (461) curved along the downstream curved path,
Since the radius of curvature (R34) of the downstream outer curved surface is smaller than the radius of curvature of the upstream outer curved surface (R33), the degree of depression of the downstream outer curved surface is larger than that of the upstream outer curved surface. The physical quantity measuring device according to D1.

[Feature D3]
The upstream outer curved surface has an upstream outer curved surface (411) curved along the upstream curved path,
The downstream outer curved surface is formed with an inward corner portion (424) which is recessed so as to enter inward in the downstream curved path so that the degree of dent of the downstream outer curved surface is larger than that of the upstream outer curved surface. The physical quantity measurement device according to Feature D1.

[Feature D4]
The inner surface of the housing is
An upstream inward curved surface (415) forming an upstream curved path from the inside of the curve;
A downstream inward curved surface (425) forming a downstream curved path from the inside of the curve;
Has
In the direction orthogonal to the center line (CL4) of the measurement flow path, the separation distance (L35b) of the portion where the downstream outer curved surface and the downstream inner curved surface are most separated is the largest between the upstream outer curved surface and the upstream inner curved surface. The physical quantity measurement device according to any one of features D1 to D3, which is larger than a separation distance (L35a) of a separated portion.

[Feature D5]
The physical quantity measuring device according to Feature D4, wherein the degree of swelling of the downstream inwardly curved surface toward the side where the measurement channel is expanded is smaller than the degree of swelling of the upstream internally curved surface toward the side where the measurement channel is expanded.

[Feature D6]
The upstream inward curved surface has an upstream inward curved surface (415) curved along the upstream curved path,
The downstream inner curved surface has a downstream inner curved surface (425) curved along the downstream curved path,
Since the radius of curvature (R32) of the downstream inward curved surface is larger than the radius of curvature of the upstream inward curved surface (R31), the degree of swelling of the downstream inner curved surface is smaller than that of the upstream inner curved surface. The physical quantity measuring device according to D5.

[Feature D7]
The physical quantity measuring device according to any one of features D1 to D6, in which the sensor path extends in a direction (Z) in which an upstream curved path and a downstream aligned path are arranged.

[Feature D8]
The housing is
A measurement narrowing unit (111, 112) that gradually reduces and narrows the measurement flow path from the measurement inlet side toward the physical quantity sensor, and gradually expands the measurement flow path from the physical quantity sensor side toward the measurement outlet. Has
The physical quantity measuring device according to any one of the features D1 to D7, wherein the measurement throttle unit is provided between the upstream end of the upstream curved path and the downstream end of the downstream curved path in the measurement flow path.

[Feature D9]
The measurement diaphragm is
A measurement throttle surface (431, 441) that forms the inner surface of the housing and gradually reduces and throttles the measurement flow path from the measurement inlet side toward the physical quantity sensor;
A measurement expansion surface (432, 442) that gradually expands the measurement flow path from the physical quantity sensor side toward the measurement outlet,
Has
Feature D8, in which the length dimension (W33a, W33b) of the measurement expansion surface is larger than the length dimension (W32a, W32b) of the measurement diaphragm surface in the direction (Z) in which the upstream curved path and the downstream curved path are arranged. Physical quantity measuring device.

[Characteristic D10]
The physical quantity measuring device according to Feature D8 or D9, in which the measurement extension surface extends straight from the physical quantity sensor side toward the measurement outlet.

[Feature D11]
The separation distance (W34a, W35a) between the downstream outer curved surface and the measurement throttle portion in the alignment direction (Z) of the upstream curved road and the downstream curved road is the distance between the upstream outer curved surface and the measurement throttle portion in the alignment direction. The physical quantity measuring device according to any one of features D8 to D10, which is larger than the distance (W34b, W35b).

[Feature D12]
The inner surface of the housing is
It has a pair of measurement wall surfaces (103, 104) that form a measurement flow path and face each other with the upstream curved surface and the downstream curved surface sandwiched therebetween.
The measurement diaphragm unit is the physical quantity measuring device according to any one of the features D8 to D11, which is provided on at least one of the pair of measurement wall surfaces.

[Feature D13]
The inner surface of the housing is
It has a pair of wall surfaces (103, 104) that form a measurement flow path and face each other with the upstream curved surface and the downstream curved surface sandwiched therebetween.
The physical quantity measurement according to any one of the features D1 to D12, in which the measurement outlet is provided in at least one of the pair of wall surfaces in a direction in which the measurement flow path is opened in the direction (X) in which the pair of wall surfaces are arranged side by side. apparatus.

[Characteristic Da1]
A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A measurement flow path (32) having a measurement inlet (35) into which the fluid flows, and a measurement outlet (36) from which the fluid introduced from the measurement inlet flows out;
A physical quantity sensor (22) provided in the measurement flow path for detecting the physical quantity of the fluid;
A housing (21) forming a measurement flow path,
Equipped with
The measurement channel is
A sensor path (405) provided with a physical quantity sensor;
An upstream curved path (406) provided in the measurement flow path between the sensor path and the measurement entrance, and curved in the housing so as to extend from the sensor path toward the measurement entrance;
A downstream curved path (407) provided between the sensor path and the measurement outlet in the measurement flow path, and curved in the housing so as to extend from the sensor path toward the measurement exit;
Has
The inner surface of the housing is
An upstream outer curved surface (411) forming an upstream curved path from the outside of the curve,
A downstream outer curved surface (421) forming a downstream curved path from the outside of the curve;
Has
An alignment line (CL31) is assumed as a virtual straight line that passes through the physical quantity sensor and extends in the alignment direction (Z) of the upstream curved road and the downstream curved road,
A physical quantity measuring device in which a distance (L31b) between the downstream outer curved surface and the physical quantity sensor on the line is larger than a distance (L31a) between the upstream outer curved surface and the physical quantity sensor on the row.

[Characteristic Da2]
The physical quantity measuring device according to Feature Da1, wherein the sensor path extends along the line.

[Characteristic Da3]
The physical quantity measuring device according to feature Da1 or Da2, wherein in the sensor road, a separation distance (L34b) between the physical quantity sensor and the downstream curved road is larger than a separation distance (L34a) between the physical quantity sensor and the upstream curved road.

[Characteristic Da4]
A sensor support part (51) supporting a physical quantity sensor in the measurement flow path,
Any of the features Da1 to Da3 in which the distance (L32b) between the downstream outer curved surface and the sensor support portion on the line of alignment is larger than the distance (L32a) between the upstream outer curved surface and the sensor support portion on the line of alignment. The physical quantity measuring device according to one.

[Characteristic Da5]
The downstream curved surface is
It has a downstream outer vertical surface (423) that is provided at a position where the line passes and that extends straight from the downstream end of the downstream curved path toward the upstream side.
The physical quantity measuring device according to any one of the features Da1 to Da4.

[Characteristic Da6]
The inner surface of the housing is
It has a downstream inward curved surface (425) forming a downstream curved path from the inside of the curve,
The curved surface in the downstream is
The physical quantity measuring device according to any one of the features Da1 to Da5, which has a downstream inner curved surface (425) that is curved along a downstream curved path.

[Characteristic Da7]
The housing is
A measurement narrowing unit (111, 112) that gradually reduces and narrows the measurement flow path from the measurement inlet side toward the physical quantity sensor, and gradually expands the measurement flow path from the physical quantity sensor side toward the measurement outlet. Has
The physical quantity measuring device according to any one of the features Da1 to Da6, wherein the measurement throttle unit is provided between the upstream end of the upstream curved path and the downstream end of the downstream curved path in the measurement flow path.

[Characteristic Da8]
The measurement diaphragm is
A measurement throttle surface (431, 441) that forms the inner surface of the housing and gradually reduces and throttles the measurement flow path from the measurement inlet side toward the physical quantity sensor;
A measurement expansion surface (432, 442) that gradually expands the measurement flow path from the physical quantity sensor side toward the measurement outlet,
Has
The physical quantity measuring device as described in the feature Da7, in which the length dimension (W33a, W33b) of the measurement expansion surface is larger than the length dimension (W32a, W32b) of the measurement diaphragm surface in the arrangement direction.

[Characteristic Da9]
The physical quantity measuring device according to Feature Da8, wherein the measurement extension surface extends straight from the physical quantity sensor side toward the measurement outlet.

[Characteristic Da10]
The distance Da (W34a, W35a) between the downstream outer curved surface and the measurement throttle section on the line is larger than the distance (W34b, W35b) between the upstream external curved surface and the measurement throttle section on the line, which is characteristic Da7. ~ The physical quantity measuring device according to any one of Da9.

[Characteristic Da11]
The inner surface of the housing is
It has a pair of measurement wall surfaces (103, 104) that form a measurement flow path and face each other with the upstream curved surface and the downstream curved surface sandwiched therebetween.
The physical quantity measuring device according to any one of the features Da7 to Da10, in which the measurement diaphragm unit is provided on at least one of the pair of measurement wall surfaces.

[Characteristic Da12]
The curved surface outside the upstream is
The physical quantity according to any one of the features Da1 to Da11, which has an upstream outer curved surface (411) that is bridged between the upstream end and the downstream end of the upstream curved road and curved along the upstream curved road. Measuring device.

[Characteristic Da13]
The inner surface of the housing is
Features Da1 to B1 that are curved so as to bulge toward the physical quantity sensor in a state of being bridged over the measurement inlet and the measurement outlet, and have an inner measurement curved surface (402) that forms the measurement flow path from the inside of the curve. The physical quantity measuring device according to any one of Da12.

[Characteristic Da14]
The inner surface of the housing is
It has a pair of wall surfaces (103, 104) that form a measurement flow path and face each other with the upstream curved surface and the downstream curved surface sandwiched therebetween.
The measurement outlet is provided on at least one of the pair of wall surfaces in a direction in which the pair of wall surfaces are aligned and opens the measurement flow channel in an orthogonal direction (X) orthogonal to the line of alignment, and the measurement outlet is any one of the features Da1 to Da13. Physical quantity measuring device described in.

<Characteristics of configuration group E>
The features disclosed in the configuration group E are included in the configurations disclosed in this specification as described below.

[Feature E1]
A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A measurement flow path (32) having a measurement inlet (35) into which the fluid flows, and a measurement outlet (36) from which the fluid introduced from the measurement inlet flows out;
A physical quantity sensor (22) provided in the measurement flow path for detecting the physical quantity of the fluid;
A sensor support part (51) supporting a physical quantity sensor in the measurement flow path,
A housing (21) forming a measurement flow path,
Equipped with
The measurement channel is
A sensor path (405) provided with a physical quantity sensor;
An upstream curved path (406) provided in the measurement flow path between the sensor path and the measurement entrance, and curved in the housing so as to extend from the sensor path toward the measurement entrance;
A downstream curved path (407) provided between the sensor path and the measurement outlet in the measurement flow path, and curved in the housing so as to extend from the sensor path toward the measurement exit;
Has
The housing is
It has a measurement throttle unit (111, 112) that gradually reduces and throttles the measurement flow path from the measurement inlet side toward the physical quantity sensor,
Assuming a line (CL31) as an imaginary straight line that passes through the physical quantity sensor and extends in the line direction (Z) of the upstream curved road and the downstream curved road, the sensor support is provided in the line cross section (CS41) extending along the line. A physical quantity measuring device in which an upstream end portion (55c, 471) of the portion is provided on the upstream side of the measurement throttle unit.

[Feature E2]
The upstream end of the sensor support is
The physical quantity measuring device according to Feature E1, which has an upstream inclined portion (471) that is inclined with respect to the aligned cross section and that straddles the upstream end portion of the measurement throttle unit in the aligned direction.

[Feature E3]
The physical quantity measuring device according to feature E1 or E2, in which the downstream end portions (55d, 472) of the sensor support portion are provided on the upstream side with respect to the downstream end portions (111c, 112c) of the measurement diaphragm portion in the aligned cross section.

[Feature E4]
The downstream end of the sensor support is
The physical quantity measuring device according to Feature E3, which has a downstream inclined portion (472) that is inclined with respect to the aligned cross section and that straddles the downstream end portion of the measurement aperture unit in the aligned direction.

[Feature E5]
The measurement diaphragm is
A measurement throttle surface (431, 441) that forms the inner surface of the housing and gradually reduces and throttles the measurement flow path from the measurement inlet side toward the physical quantity sensor;
A measurement expansion surface (432, 442) that gradually expands the measurement flow path from the physical quantity sensor side toward the measurement outlet,
Has
The physical quantity measuring device according to any one of features E1 to E4, in which the length dimension (W33a, W33b) of the measurement expansion surface is larger than the length dimension (W32a, W32b) of the measurement diaphragm surface in the arrangement direction.

[Feature E6]
The physical quantity sensor is mounted on the surface (55e) that is one surface of the sensor support portion,
The inner surface of the housing is
A front measurement wall surface (103) facing the surface of the sensor support,
A back measurement wall surface (104) facing the back surface (55f) opposite to the front surface of the sensor support,
Has a pair of wall surfaces that form a measurement flow path and face each other with the sensor support portion interposed therebetween.
The housing is
The physical quantity measuring device as described in any one of the features E1 to E5, which includes, as a measurement diaphragm section, a surface diaphragm section (111) provided at a position facing a physical quantity sensor on a surface measurement wall surface.

[Feature E7]
The housing is
The physical quantity measuring device according to Feature E6, which includes, as the measurement diaphragm section, a back diaphragm section (112) provided at a position opposite to the front diaphragm section on the back measurement wall surface via a physical quantity sensor.

[Feature E8]
The physical quantity measuring device according to feature E7, in which the distance (D33a) between the sensor support portion and the front diaphragm portion is smaller than the distance (D33b) between the sensor support portion and the rear diaphragm portion in the aligned cross section.

[Feature E9]
The center line (CL4) of the measurement flow passage extends along the measurement flow passage through the center (CO2) of the measurement inlet and the center (CO3) of the measurement outlet,
The front narrowing portion has a front top portion (111a) as a top portion at which the distance (W2) between the front narrowing portion and the center line of the measurement flow path is smallest.
The back narrowing portion has a back top portion (112a) as a top portion where the distance (W3) between the back narrowing portion and the center line of the measurement flow path is smallest.
The physical quantity measuring device according to feature E7 or E8, in which a reduction rate at which the front throttle section reduces the measurement flow channel is larger than a reduction rate at which the back throttle section reduces the measurement flow channel.

[Feature E10]
The physical quantity measuring device according to any one of features E1 to E9, in which a physical quantity sensor is provided in the measurement flow passage in accordance with a position where the flow velocity is maximized by the measurement throttle portion narrowing the measurement flow passage.

[Feature E11]
The physical quantity measuring device according to any one of features E1 to E10, in which the upstream end portion of the sensor support portion is provided in the upstream curved path in the aligned cross section.

[Feature E12]
The physical quantity measuring device according to any one of features E1 to E11, in which the opening area of the measurement outlet is smaller than the opening area of the measurement inlet.

[Feature E13]
A passage channel (31) having a passage inlet (33) into which the fluid flows, and a passage outlet (34) from which the fluid introduced from the passage inlet flows out;
The measurement channel is a branch channel branched from the passage channel,
The physical quantity measuring device according to any one of features E1 to E12, in which the opening area of the passage outlet is smaller than the opening area of the passage inlet.

<Characteristics of Component Group Z>
The configuration disclosed in this specification includes the features of the configuration group Z as described below.

[Characteristic Z1]
A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A measurement flow path (32) having a measurement inlet (35) into which the fluid flows, and a measurement outlet (36) from which the fluid introduced from the measurement inlet flows out;
A physical quantity sensor (22) provided in the measurement flow path for detecting the physical quantity of the fluid;
A housing (21) forming a measurement flow path,
A physical quantity measuring device equipped with.

According to this feature Z1, the physical quantity can be detected by the physical quantity sensor for the fluid flowing from the measurement inlet into the measurement flow path. Note that, among the configurations disclosed in this specification, the configurations not included in the feature Z1 are not essential configurations. Although there are some problems in this specification, the feature Z1 is an indispensable configuration for solving these problems.

<Code of configuration group A>
20... Air flow meter as a physical quantity measuring device, 21... Housing, 22... Flow rate sensor as a physical quantity sensor, 32... Measuring flow path, 35... Measuring inlet, 36... Measuring outlet, 50... Sensor SA as detecting unit, 51... Sensor support portion, 55... Mold portion as protective resin portion, 55a... Mold tip surface as support tip portion, 55e... Mold surface as support surface, 55f... Mold back surface as support back surface, 65... Sensor substrate, 65a. Sensor substrate surface as one surface, 71... Heating resistor as a heater section, 72... Upstream temperature measuring resistor as a temperature detecting section, 73... Downstream temperature measuring resistor as a temperature detecting section, 101... Measurement as a floor surface Floor surface, 103... Front measurement wall surface as front wall surface, 104... Back measurement wall surface as back wall surface, 111... Front narrowing portion, 111a... Front top portion, 112... Back narrowing portion, 122... Front area, 122a... Floor side area , 122b... Ceiling side area, CO1... Center of measurement inlet, CO2... Center of measurement outlet, CL4... Center line of measurement flow path, L1... Front distance, L2... Back distance, L3... Floor distance, S1... Cross sectional area, S2... Floor side area, S3... Ceiling side area, W1... Measured width dimension, W2... Separation distance, X... Width direction as front/back direction, Y... Height direction.

<Code of configuration group B>
20... Air flow meter as physical quantity measuring device, 21... Housing, 22... Flow rate sensor as physical quantity sensor, 32... Measurement flow path, 50... Sensor SA as detection unit, 51... Sensor support portion, 131... Housing partition portion, Reference numeral 135... Housing channel surface, 136... Housing receiving surface, 137... Housing step surface as housing intersecting surface, 145... SA channel surface as unit channel surface, 146... SA receiving surface as unit receiving surface, 147... Unit intersecting surface SA stepped surface as 150, SA accommodation area as accommodation area, 161... SA recessed portion as unit recessed portion, 162... SA partition portion as unit partitioning portion, 163... Housing recessed portion, 200... Air flow meter as physical quantity measuring device , 201... Housing, 202... Flow rate sensor as physical quantity sensor, 212... Measurement flow path, 220... Sensor SA as detection unit, 221... Sensor support part, 271... Housing partition part, 275... Housing flow path surface, 276... Housing Housing surface, 277... Housing step surface as housing intersecting surface, 285... SA channel surface as unit channel surface, 286... SA housing surface as unit housing surface, 287... SA step surface as unit intersecting surface, 290... Housing SA accommodation area as an area, 302... SA partition portion as a unit partition portion, CL11, CL13... Center line, Y... Height direction as an array direction, θ11... Flow path side angle, θ12... Accommodation side angle, θ13... Flow Road side angle, θ14... Storage side angle.

<Code of Configuration Group C>
14... Piping unit as attachment target, 20... Air flow meter as physical quantity measuring device, 21... Housing, 22... Flow rate sensor as physical quantity sensor, 27a... Angle setting surface, 31... Pass passage, 32... Measurement passage, 33... passage entrance, 34... passage exit, 35... measurement entrance, 36... measurement exit, 331... entrance passage, 342... ceiling ceiling surface as a sloped surface 342a... ceiling sloped surface, 346... entrance floor surface, CL23 ... Center line, CL24... Entrance passage line, H21... Separation distance, S21... Cross-sectional area, Z... Depth direction as aligned direction and mainstream direction, .theta.21, .theta.22, .theta.25, .theta.26... Inclination angle.

<Code of configuration group D>
20... Air flow meter as physical quantity measuring device, 21... Housing, 22... Flow rate sensor as physical quantity sensor, 32... Measurement flow path, 35... Measurement inlet, 36... Measurement outlet, 51... Sensor support part, 103... Measurement wall surface and Front measurement wall surface as a wall surface, 104... Back measurement wall surface as a measurement wall surface and wall surface, 111... Front diaphragm portion as a measurement diaphragm portion, 112... Back diaphragm portion as a measurement diaphragm portion, 402... Internal measurement curved surface, 405... Sensor path, 406... Upstream curved path, 407... Downstream curved path, 411... Upstream outer curved surface as upstream outer curved surface, 415... Upstream inner curved surface as upstream upstream curved surface, 421... Downstream outer curved surface, 424... Corners on the downstream/outward entrance/exit, 425... Curved surface on the downstream side as curved surface on the downstream side, 431... Surface drawing surface as measurement diaphragm surface, 432... Surface expansion surface as measurement expansion surface, 441... As measurement diaphragm surface Back expansion surface, 442... back expansion surface as measurement expansion surface, 461... downstream curved surface, CL4... center line, L35a, L35b... separation distance, R31, R32, R33, R34... radius of curvature, W32a, W32b, W33a, W33b... Length dimension, W34a, W34b, W35a, W35b... Separation distance, X... Width direction, Z... Depth direction as arrangement direction.

<Code of configuration group E>
20... Air flow meter as physical quantity measuring device, 21... Housing, 22... Flow rate sensor as physical quantity sensor, 31... Passage channel, 32... Measurement channel, 33... Passage inlet, 34... Passage outlet, 35... Measurement inlet, 36... Measurement outlet, 51... Sensor support portion, 55c... Mold upstream surface as upstream end portion, 55d... Mold downstream surface as downstream end portion, 55e... Mold front surface as surface, 55f... Mold back surface as back surface, 103 ... front measurement wall surface as a wall surface, 104... back measurement wall surface as a wall surface, 111... front drawing portion as a measurement diaphragm portion, 111a... front top portion, 111c... front surface downstream end portion as a downstream end portion, 112... measurement diaphragm portion , 112a... Back top part, 112c... Back downstream end as downstream end, 402... Internal measurement curved surface, 405... Sensor path, 406... Upstream curved path, 407... Downstream curved path, 411... Upstream Upstream outer curved surface as an outer curved surface, 415... Upstream inner curved surface as an upstream inner curved surface, 421... Downstream outer curved surface, 431... Front diaphragm surface as a measurement diaphragm surface, 432... Table expanded surface as a measurement expanded surface , 441... A back drawing surface as a measurement drawing surface, 442... A back expanding surface as a measurement expanding surface, 471... A mold upstream inclined surface as an upstream end portion and an upstream inclined portion, 472... As a downstream end portion and a downstream inclined portion Mold downstream inclined surface, CL31... Line, CS... Line, CO2, CO3... Center, CL4... Center line, D33a, D33b... Separation distance, W2, W3... Separation distance, W32a, W32b, W33a, W33b... Length Dimension, Z... Depth direction as the arrangement direction.

Claims (9)

A physical quantity measuring device (20) for measuring a physical quantity of a fluid, comprising:
A passage channel (31) having a passage inlet (33) into which the fluid flows, and a passage outlet (34) from which the fluid that has flowed in from the passage inlet flows out;
A measurement flow path (32) branched from the passage flow path for measuring a physical quantity of the fluid, the measurement flow path (32) being provided between the passage entrance and the passage exit, and the fluid flowing in from the passage flow path. A measurement flow path (32) having a measurement inlet (35) and a measurement outlet (36) through which the fluid flowing from the measurement inlet flows out;
A physical quantity sensor (22) provided in the measurement flow path, for detecting a physical quantity of the fluid;
A housing (21) forming the passage channel and the measurement channel,
Equipped with
The inner surface of the housing is
In the passage passage, an inlet passage (331) is formed across the passage inlet and the measurement inlet, and the passage inlet and the measurement are formed in a direction (Z) in which the passage inlet and the passage outlet are lined up. The entrance ceiling surface (342) that was laid across the entrance,
An entrance floor surface (346) that forms the entrance passage and faces the entrance ceiling surface through the entrance passage;
Has
The entrance ceiling surface is
The distance (H21) from the entrance floor surface is inclined with respect to the entrance floor surface such that it gradually decreases from the passage entrance toward the passage exit, and extends from the passage entrance toward the measurement inlet. A physical quantity measuring device having a ceiling inclined surface (342, 342a). The physical quantity measuring device according to claim 1, wherein an inclination angle (θ21) of the inclined ceiling surface with respect to the entrance floor surface is 10 degrees or more. The physical quantity measuring device according to claim 1 or 2, wherein the ceiling inclined surface is inclined with respect to the entrance floor surface so as to face the passage entrance side. 4. The ceiling inclined surface is inclined so as to face the passage inlet side with respect to a mainstream direction (Z) which is a direction in which a mainstream of the fluid mainly flowing into the passage inlet travels. The physical quantity measuring device according to any one of 1. The physical quantity measuring device according to claim 4, wherein an inclination angle (θ22) of the inclined surface of the ceiling with respect to the mainstream direction is 10 degrees or more. The housing is
An angle setting surface (27a) for setting an attachment angle of the housing with respect to an attachment object (14) to which the housing is attached,
The physical quantity measuring device according to claim 4 or 5, wherein the mainstream direction is a direction in which the angle setting surface extends. The physical quantity measuring device according to claim 1, wherein a cross-sectional area (S21) of the entrance passage gradually decreases from the passage entrance toward the measurement entrance. The inclination angle (θ25) of the center line (CL23) of the measurement flow path at the measurement inlet with respect to the entrance passage line (CL24) that is the center line of the entrance passage is 90 degrees or more. The physical quantity measuring device according to any one of claims. The physical quantity measuring device according to claim 1, wherein a branch angle (θ26) of the measurement flow path with respect to the passage flow path is 60 degrees or less.

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