JP7356957B2 - Physical quantity detection device - Google Patents

Description

The present disclosure relates to a physical quantity detection device.

2. Description of the Related Art An invention related to a physical quantity detection device for detecting a physical quantity of intake air of an internal combustion engine has been known (Patent Document 1 listed below). The conventional physical quantity detection device described in Patent Document 1 includes a flow rate sensor forming a sensing part that detects the pressure of the gas to be measured flowing in the main passage, an electronic component that drives a semiconductor element, and a sensing unit other than the flow rate. (paragraph 0009 of the same).

This conventional physical quantity detection device has the following steps in order to seal the connection terminal part with a sealing material without covering the sensing part with the sealing material for a plurality of physical quantity measuring sensors having a sensing part mounted on the substrate. A sealing material formed in advance into a three-dimensional shape is used. In this conventional physical quantity detection device, a sealing material formed in a three-dimensional shape is placed on a substrate on which a physical quantity measurement sensor is mounted, and then heated and molded to seal the connection terminal with the sensing part exposed. It is characterized by

Japanese Patent Application Publication No. 2020-003439

The conventional physical quantity detection device seals the connection terminal of the physical quantity measurement sensor by heating and molding a sealing material formed into a three-dimensional shape, so there is room for improvement in simplifying the manufacturing process and reducing component costs. . When applying a curable sealant to seal the connection terminal, it is possible to simplify the manufacturing process and reduce component costs.

However, when the connection terminals of a chip package whose height from the surface of the substrate is relatively high are sealed by applying a curable sealant, air pockets are likely to occur between the connection terminals. Such air pockets may move to the surface of the curable sealant when the curable sealant is cured and expose the connection terminals.

The present disclosure provides a physical quantity detection device that can suppress the generation of air pockets when applying a curable sealing material to seal connection terminals of a chip package.

One aspect of the present disclosure is a physical quantity detection device that detects a physical quantity of a gas to be measured flowing through a main passage, comprising: a sub-passage for taking in the gas to be measured from the main passage and detouring the gas to be measured; A flow rate sensor that detects the flow rate of measurement gas, a chip package that drives the flow rate sensor, a circuit board on which connection terminals of the chip package are mounted, a circuit chamber that accommodates the circuit board, and a circuit chamber that seals the connection terminals. a curable encapsulant for sealing, the chip package having a proximal end disposed in the circuit chamber and provided with the connection terminal, and a proximal end disposed in the sub passageway and provided with the flow rate sensor. It has a tip and a bottom surface forming an air passage between it and the circuit board, and the air passage communicates between the curable sealant and the sub-passage. It is a physical quantity detection device.

According to the above aspect of the present disclosure, it is possible to provide a physical quantity detection device that can suppress the generation of air pockets when applying a curable sealant to seal connection terminals of a chip package. can.

FIG. 1 is a system diagram showing an embodiment of a physical quantity detection device according to the present disclosure. FIG. 2 is a front view of the physical quantity detection device shown in FIG. 1; FIG. 2 is a rear view of the physical quantity detection device in FIG. 1; FIG. 2 is a left side view of the physical quantity detection device in FIG. 1; 2 is a right side view of the physical quantity detection device in FIG. 1. FIG. FIG. 2 is a top view of the physical quantity detection device in FIG. 1; FIG. 2B is a front view of the physical quantity detection device of FIG. 2A before a sealing material is placed. FIG. 2B is a rear view of the physical quantity detection device of FIG. 2B before the cover is attached. FIG. 4 is a rear view showing a modification of the physical quantity detection device shown in FIG. 3B. A cross-sectional view of the physical quantity detection device along line III(D)-III(D) in FIG. 3B. FIG. 2A is a cross-sectional view of the physical quantity detection device taken along line III(E)-III(E) in FIG. 2A. FIG. 3B is a front view of the circuit board of the physical quantity detection device of FIG. 3B. 4B is a right side view of the circuit board of FIG. 4A. FIG. FIG. 4A is a cross-sectional view of the circuit board taken along line IV(C)-IV(C) in FIG. 4A. FIG. 4A is a cross-sectional view of the circuit board taken along line IV(D)-IV(D) in FIG. 4A. FIG. 4B is a bottom view of the chip package mounted on the circuit board of FIG. 4A.

Hereinafter, embodiments of a physical quantity detection device according to the present disclosure will be described with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of a physical quantity detection device according to the present disclosure. The physical quantity detection device 100 of this embodiment is used, for example, in an internal combustion engine control system 1 using an electronic fuel injection method. The internal combustion engine control system 1 includes, for example, an internal combustion engine 10, a physical quantity detection device 100, a throttle valve 25, a throttle angle sensor 26, an idle air control valve 27, an oxygen sensor 28, and a control device 4. There is.

For example, the physical quantity detection device 100 is inserted into the main passage 22 through a mounting hole provided in the passage wall of the intake body, which is the main passage 22, and is used while being fixed to the passage wall of the main passage 22. The physical quantity detection device 100 detects a physical quantity of intake air, which is the gas to be measured 2 taken in through the air cleaner 21 and flows through the main passage 22 , and outputs it to the control device 4 . The physical quantity detection device 100 protrudes in the radial direction of the main passage 22 from the passage wall of the main passage 22 toward the center line 22 a of the main passage 22 along the main flow direction of the gas to be measured 2 flowing through the main passage 22 . That is, the protruding direction of the physical quantity detection device 100 in the main passage 22 is, for example, a direction perpendicular to the center line 22a of the main passage 22.

The throttle valve 25 is built in, for example, a throttle body 23 disposed upstream of the intake manifold 24 in the flow direction of the gas to be measured 2 . The control device 4 changes the opening degree of the throttle valve 25 based on the operation amount of the accelerator pedal, for example, and controls the flow rate of intake air as the gas to be measured 2 flowing into the combustion chamber in the cylinder 11 of the internal combustion engine 10. do. The throttle angle sensor 26 measures the opening degree of the throttle valve 25 and outputs it to the control device 4 . Idle air control valve 27 controls the amount of air that bypasses throttle valve 25.

The internal combustion engine 10 includes, for example, a cylinder 11, a piston 12, a spark plug 13, a fuel injection valve 14, an intake valve 15, an exhaust valve 16, and a rotation angle sensor 17. Intake air taken in through the air cleaner 21 based on the operation of the piston 12 of the internal combustion engine 10 flows through the main passage 22, and its flow rate is controlled by the throttle valve 25 in the throttle body 23. The intake air that has passed through the throttle body 23 passes through an intake manifold 24, further passes through a fuel injection valve 14 provided at an intake port, and flows into a combustion chamber within the cylinder 11 via an intake valve 15.

The control device 4 controls the fuel injection valve 14 based on the physical quantity of the intake air as the gas to be measured 2 inputted from the physical quantity detection device 100 to inject fuel into the intake air. As a result, the intake air that has passed through the intake manifold 24 is mixed with the fuel injected from the fuel injection valve 14, and is guided into the combustion chamber in the form of an air-fuel mixture. The control device 4 explosively burns the air-fuel mixture in the combustion chamber by spark ignition from the spark plug 13, and causes the internal combustion engine 10 to generate mechanical energy.

The rotation angle sensor 17 detects information regarding the positions and states of the piston 12, the intake valve 15, and the exhaust valve 16, as well as the rotational speed of the internal combustion engine 10, and outputs the information to the control device 4. Gas generated by combustion is discharged from the combustion chamber of the cylinder 11 to the exhaust pipe via the exhaust valve 16, and is discharged as exhaust gas 3 to the outside of the vehicle from the exhaust pipe. The oxygen sensor 28 is provided in the exhaust pipe, measures the oxygen concentration of the exhaust gas 3 flowing through the exhaust pipe, and outputs the measured oxygen concentration to the control device 4 .

The control device 4 controls each part of the internal combustion engine control system 1 based on the physical quantities of the intake air as the gas to be measured 2 flowing through the main passage 22 detected by the physical quantity detection device 100, such as flow rate, temperature, humidity, pressure, etc. control. Specifically, when the control device 4 controls the opening degree of the throttle valve 25 based on the operation amount of the accelerator pedal, the flow rate of intake air as the gas to be measured 2 flowing through the main passage 22 changes. The control device 4 controls the amount of fuel injected from the fuel injection valve 14 based on the flow rate of the gas to be measured 2 detected by the physical quantity detection device 100, for example. Thereby, the mechanical energy generated by the internal combustion engine 10 is controlled.

The control device 4 calculates the fuel injection amount and ignition timing based on the physical quantity of intake air, which is the output of the physical quantity detection device 100, and the rotation speed of the internal combustion engine 10, which is measured based on the output of the rotation angle sensor 17. do. Based on these calculation results, the control device 4 controls the amount of fuel injected by the fuel injection valve 14 and the ignition timing of the spark plug 13.

In reality, the control device 4 further determines the fuel level based on the temperature of the gas to be measured 2, the changing state of the opening degree of the throttle valve 25, the changing state of the rotational speed of the internal combustion engine 10, and the state of the air-fuel ratio of the exhaust gas 3. The supply amount and ignition timing are precisely controlled. The control device 4 further controls the amount of air bypassing the throttle valve 25 using the idle air control valve 27 when the internal combustion engine 10 is in an idling operating state, and controls the rotational speed of the internal combustion engine 10 in the idling operating state.

The fuel supply amount and ignition timing, which are the main control variables of the internal combustion engine 10, are both calculated using the output of the physical quantity detection device 100 as a main parameter. Therefore, improving the detection accuracy, suppressing changes over time, and improving the reliability of the physical quantity detection device 100 are important in improving the control accuracy and ensuring reliability of the vehicle.

Particularly in recent years, there has been a very high demand for fuel efficiency of vehicles, and also a very high demand for exhaust gas purification. In order to meet these demands, it is extremely important to improve the detection accuracy of the physical quantity of intake air detected by the physical quantity detection device 100. It is also important that the physical quantity detection device 100 maintains high reliability.

A vehicle equipped with the physical quantity detection device 100 is used in an environment with large changes in temperature and humidity. It is desirable for the physical quantity detection device 100 to take into account measures such as changes in temperature and humidity in the environment in which it is used, as well as measures against dust and pollutants.

Further, the physical quantity detection device 100 is attached to an intake pipe that is affected by heat generated from the internal combustion engine. Therefore, heat generated by the internal combustion engine is transmitted to the physical quantity detection device 100 via the intake pipe. Since the physical quantity detection device 100 detects the flow rate of the gas to be measured 2 by performing heat transfer with the gas to be measured 2, it is important to suppress the influence of heat from the outside as much as possible.

The physical quantity detection device 100 of this embodiment will be described in more detail below with reference to FIGS. 2A to 2E, 3A to 3E, and 4A to 4E. In addition, in each of these figures, the X-axis parallel to the protruding direction of the physical quantity detection device 100 in the main passage 22 shown in FIG. A rectangular coordinate system is shown with the Z-axis parallel to the direction. In the following description, it is assumed that the gas to be measured 2 flows along the center line 22a (Y-axis) of the main passage 22.

2A to 2E are a front view, a back view, a left side view, a right side view, and a top view of the physical quantity detection device 100 of FIG. 1, respectively. The physical quantity detection device 100 includes, for example, a housing 110 and a cover 120.

Housing 110 is manufactured, for example, by injection molding a synthetic resin material. The cover 120 is a plate-shaped member made of metal or synthetic resin, for example. For the cover 120, for example, a molded product made of a synthetic resin material can be used. The housing 110 and the cover 120 constitute a casing of the physical quantity detection device 100 disposed within the main passage 22.

The housing 110 includes, for example, a flange 111, a connector 112, and a measuring section 113.

As shown in FIG. 2E, the flange 111 has a generally rectangular plate shape and has a pair of fixing parts 111a at diagonal corners. The fixing part 111a has a cylindrical through-hole 111b in the center that passes through the flange 111 and into which a fixing screw is inserted. To fix the physical quantity detection device 100 to the main passage 22, the measuring section 113 is inserted into a mounting hole provided in the main passage 22. Then, the fixing screw inserted through the through hole 111b of the flange 111 is screwed into the screw hole of the main passage 22 to fix the flange 111 to the passage wall of the main passage 22. Thereby, the physical quantity detection device 100 is fixed to the main passage 22, which is the intake body.

The connector 112 protrudes from the flange 111, is disposed outside the main passage 22 that is the intake body, and is connected to external equipment. As shown in FIG. 2D, inside the connector 112, a plurality of external terminals 112a and a correction terminal 112b are provided. The external terminal 112a includes, for example, an output terminal for physical quantities such as flow rate and temperature, which are measurement results of the physical quantity detection device 100, and a power supply terminal for supplying DC power to operate the physical quantity detection device 100.

The correction terminal 112b is used to measure a physical quantity after manufacturing the physical quantity detection apparatus 100, obtain a correction value for each physical quantity detection apparatus 100, and store the correction value in the internal memory of the physical quantity detection apparatus 100. In the subsequent measurement of the physical quantity by the physical quantity detection device 100, correction data based on the correction value stored in the memory is used, and the correction terminal 112b is not used.

The measuring portion 113 extends from a flange 111 fixed to a passage wall of the main passage 22 toward the center line 22a of the main passage 22 so as to protrude in the radial direction of the main passage 22 perpendicular to the center line 22a. The measurement unit 113 has a flat rectangular shape that is generally a rectangular parallelepiped. The measuring section 113 has a length in the protruding direction (X-axis direction) of the measuring section 113 in the main passage 22 and a width in the main flow direction (Y-axis direction) of the gas to be measured 2 in the main passage 22. There is. Furthermore, the measurement section 113 has a thickness in the protruding direction (X-axis direction) and in the direction (Z-axis direction) perpendicular to the main flow direction (Y-axis direction) of the gas to be measured 2 . In this way, since the measuring section 113 has a flat shape along the main flow direction of the gas to be measured 2, fluid resistance to the gas to be measured 2 can be reduced.

The measurement unit 113 has a front surface 113a, a back surface 113b, an upstream side surface 113c, a downstream side surface 113d, and a lower surface 113e. The front surface 113a and the back surface 113b have a larger area than other surfaces of the measuring section 113, and are generally parallel to the protruding direction of the measuring section 113 (X-axis direction) and the center line 22a of the main passage 22 (Y-axis direction). The upstream side surface 113c and the downstream side surface 113d have an elongated shape with a smaller area than the front surface 113a and the rear surface 113b, and are generally orthogonal to the centerline 22a (Y-axis direction) of the main passage 22. The lower surface 113e has a smaller area than the other surfaces of the measurement section 113, and is generally parallel to the center line 22a (Y-axis direction) of the main passage 22 and generally orthogonal to the protruding direction (X-axis direction) of the measurement section 113. .

The measurement unit 113 has a sub passage inlet 114 on an upstream side surface 113c, and has a first outlet 115 and a second outlet 116 on a downstream side surface 113d. The sub-passage inlet 114, the first outlet 115, and the second outlet 116 are provided at the distal end of the measuring section 113 on the distal side of the center in the protruding direction (X-axis direction) of the measuring section 113. Thereby, the gas to be measured 2 near the center of the main passage 22, which is away from the inner wall surface of the main passage 22, can be taken in from the sub passage entrance 114. Therefore, the physical quantity detection device 100 can suppress a decrease in measurement accuracy due to the influence of heat of the internal combustion engine 10.

FIG. 3A is a front view of the physical quantity detection device 100 of FIG. 2A before the sealing material 119 is placed. FIG. 3B is a rear view of the physical quantity detection device 100 of FIG. 1 before the cover 120 is attached. FIG. 3C is a rear view showing a modification of the physical quantity detection device 100 of FIG. 3B. FIG. 3D is a cross-sectional view of the physical quantity detection device 100 taken along line III(D)-III(D) in FIG. 3B. FIG. 3E is a cross-sectional view of the physical quantity detection device 100 taken along line III(E)-III(E) in FIG. 2A.

The external terminal 112a of the connector 112 shown in FIG. 2D is connected to a pad of the circuit board 140 via a bonding wire 143, for example, as shown in FIG. 3A. For example, a protection circuit 144 is mounted on the surface of the circuit board 140 to which the bonding wire 143 is connected. Protection circuit 144 stabilizes the voltage within the circuit and eliminates noise. These bonding wires 143 and protection circuit 144 are covered and sealed with a sealing material 119, as shown in FIG. 2A. As the sealant 119, for example, silicone gel or an epoxy sealant having higher rigidity than a silicone sealant can be used.

As shown in FIG. 3B, the housing 110 has a concave auxiliary passage groove 117 and a concave circuit chamber 118 on the back surface 113b side of the measurement section 113. As shown in FIG. 3E, the opening of the sub passage groove 117 is closed by the cover 120, thereby forming a sub passage 130 together with the cover 120. The sub passage 130 takes in the gas to be measured 2 flowing through the main passage 22 and detours it. The gas to be measured 2 flowing through the main passage 22 is taken into the sub-passage 130 from the sub-passage entrance 114 that opens on the upstream side surface 113c of the measurement section 113, for example, as shown in FIG. 3B.

The sub passage groove 117 includes, for example, a first sub passage groove 117a and a second sub passage groove 117b. As shown in FIG. 3B, the first sub-passage groove 117a extends from the sub-passage entrance 114 that opens on the upstream side surface 113c of the measuring section 113 to the first outlet 115 that opens on the downstream side surface 113d of the measuring section 113. , extends along the center line 22a (Y-axis direction) of the main passage 22. The first sub passage groove 117a forms a first sub passage 131 with the cover 120, for example, as shown in FIG. 3E. The first sub-passage 131 returns the measured gas 2 taken in from the sub-passage inlet 114 to the main passage 22 from the first outlet 115.

As shown in FIG. 3B, the second sub passage groove 117b branches from the middle of the first sub passage groove 117a and extends toward the flange 111 along the protruding direction (X-axis direction) of the measuring section 113. . Further, the second sub passage groove 117b is curved in a U-shape so as to be folded back in the opposite direction, and extends toward the distal end of the measuring section 113 along the protruding direction (X-axis direction) of the measuring section 113. The second sub passage groove 117b is a second outlet that curves in a direction along the center line 22a (Y-axis direction) of the main passage 22 at the distal end of the measurement part 113 and opens on the downstream side surface 113d of the measurement part 113. 116. For example, as shown in FIG. 3D, the opening of the second sub-passage groove 117b is closed by the cover 120, thereby forming a second sub-passage 132 between the second sub-passage groove 117b and the cover 120. The sub-passage 130 includes a first sub-passage 131 and a second sub-passage 132.

The circuit chamber 118 is provided in a concave shape on the rear surface 113b side of the measurement section 113 of the housing 110 and on the proximal end side of the measurement section 113 connected to the flange 111, and accommodates the circuit board 140. The circuit chamber 118 is located closer to the proximal end of the measurement unit 113 than the first sub-passage groove 117a of the sub-passage groove 117 and is a second sub-passage in the main flow direction (Y-axis direction) of the gas to be measured 2 flowing through the main passage 22. It is provided adjacent to the upstream side of the groove 117b.

FIG. 4A is a front view of the circuit board 140 of the physical quantity detection device 100 of FIG. 3B. FIG. 4B is a right side view of circuit board 140 of FIG. 4A. FIG. 4C is a cross-sectional view of the circuit board 140 taken along line IV(C)-IV(C) in FIG. 4A. FIG. 4D is a cross-sectional view of the circuit board 140 taken along line IV(D)-IV(D) in FIG. 4A. FIG. 4E is a bottom view of the chip package 150 mounted on the circuit board 140 of FIG. 4A.

As shown in FIG. 4C, the chip package 150 has a configuration in which a flow rate sensor 151 and an electronic component 152 are integrally sealed by, for example, transfer molding of thermosetting resin. Chip package 150 drives flow sensor 151 by electronic component 152, for example. The electronic component 152 is, for example, an LSI, is connected to the flow rate sensor 151 via a lead frame 154, and drives the flow rate sensor 151.

The flow rate sensor 151 is, for example, a thermal flow rate sensor, and as shown in FIGS. 4C and 4E, the gas to be measured flows through the measurement passage 132a formed between the circuit board 140 and the groove 150c of the chip package 150. Measure the flow rate of step 2. The measurement passage 132a is formed, for example, in the second sub passage groove 117b of the sub passage groove 117, that is, within the second sub passage 132 of the sub passage 130, as shown in FIGS. 3B and 3D.

As shown in FIG. 4A, connection terminals 153 of a chip package 150 are mounted on the circuit board 140. The connection terminal 153 is connected to the electronic component 152 via a lead frame 154, for example. The connection terminal 153 is mounted on the circuit board 140 via the bonding material 142, for example. As the bonding material 142, for example, solder, solder paste, or other conductive material can be used. The connection terminal 153 is sealed with a curable sealant 141, as shown in FIG. 3B or 3C.

As the curable sealant 141, for example, a silicone sealant can be used. The physical property values of the silicone sealant used as the curable sealant 141 are as follows, for example. The viscosity before curing is, for example, about 25 [Pa·s] to about 60 [Pa·s]. The thixometry ratio is, for example, about 1.55. The density is, for example, 1 [g/cm ³ ] to 1.3 [g/cm ³ ]. Standard curing conditions are, for example, about 100 [° C.] to about 140 [° C.] for about 30 minutes to about 60 minutes. The penetration is, for example, about 11 to about 35. The coefficient of linear expansion is about 200 [×10 ⁶ /°C] to about 400 [×10 ⁶ /°C]. The Young's modulus after curing is, for example, about 0.03 [MPa] to about 2 [MPa]. Poisson's ratio is, for example, about 0.4 to about 0.5.

As shown in FIGS. 3B, 4A, and 4C, the chip package 150 has a base end 150b disposed in the circuit chamber 118 and provided with a connection terminal 153, and a base end 150b disposed in the second sub-passage 132 of the sub-passage 130. and a distal end portion 150a provided with a flow rate sensor 151. Further, the chip package 150 has a bottom surface 150d that forms an air passage AP between the chip package 150 and the circuit board 140, as shown in FIGS. 4C, 4D, and 4E. In other words, the bottom surface 150d of the chip package 150 is at a higher position in the height direction of the chip package 150, which is the normal direction of the circuit board 140, than other parts of the chip package 150 that are in contact with the circuit board 140, that is, the bottom surface 150d of the chip package 150 is located at a higher position than other parts of the chip package 150 that are in contact with the circuit board 140. 140.

More specifically, as shown in FIG. 4D, the connection terminals 153 of the chip package 150 protrude from the side surface of the base end 150b that intersects the bottom surface 150d in the direction along the mounting surface 140a of the circuit board 140, and are connected to the circuit board 140. It is bent towards. Furthermore, the connection terminals 153 bent toward the circuit board 140 are mounted in such a manner that the closer they get to the mounting surface 140a, the further away from the base end 150b, in the width direction WD of the chip package 150 along the mounting surface 140a of the circuit board 140. It is inclined with respect to the normal direction of the surface 140a.

Furthermore, the connection terminal 153 is bent toward the outside in the width direction WD of the chip package 150 along the mounting surface 140a near the circuit board 140, and is in contact with a land on the mounting surface 140a of the circuit board 140. As shown in FIG. 4D, the bottom surface 150d of the chip package 150 and the circuit board 140 face each other with an interval d in a state where the plurality of connection terminals 153 are in contact with the circuit board 140. An air passage AP is formed between the bottom surface 150d and the circuit board 140.

Here, the width of the connection terminal 153 is, for example, about 0.1 [mm] to 0.5 [mm], and in this embodiment is about 0.3 [mm]. Further, the thickness of the connection terminal 153 is, for example, about 0.1 [mm] to 0.5 [mm]. Further, the pitch of the connection terminals 153 is, for example, about 0.5 [mm] to 1 [mm], and in this embodiment is about 0.75 [mm]. Further, the height from the lower surface of the tip of the connecting terminal 153 in contact with the circuit board 140 to the upper surface of the base end of the connecting terminal 153 protruding from the side surface of the base end portion 150b is, for example, 1 [mm] to 2 [mm]. In this embodiment, it is about 1.68 [mm].

Further, the circuit board 140 has an extending portion 140b extending from the circuit chamber 118 toward the second sub-passage groove 117b forming the sub-passage 130, as shown in FIGS. 3B and 4A. The extending portion 140b extends from the circuit chamber 118 to the second sub-passage groove 117b along the tip portion 150a of the chip package 150 in the main flow direction (Y-axis direction) of the gas to be measured 2 flowing through the main passage 22. There is.

As shown in FIGS. 4C and 4E, the chip package 150 has a contact portion 150e on the distal end side of the flow rate sensor 151, and the extended portion 140b of the circuit board 140 and the contact portion 150e of the chip package 150 are connected to each other. are in contact with each other. In this state, the bottom surface 150d of the chip package 150 and the circuit board 140 face each other with a distance d between them, and an air passage AP is formed between the bottom surface 150d and the circuit board 140. The distance d between the bottom surface 150d of the chip package 150 and the circuit board 140 can be set, for example, in a range of about 0.01 [mm] to about 0.5 [mm], and in this embodiment, about 0.01 mm. It is 1 [mm].

For example, as shown in FIG. 4E, the contact portion 150e extends in the width direction WD of the chip package 150 along the groove 150c. Further, the contact portion 150e is in contact with the circuit board 140 at a predetermined width along the length direction LD of the chip package 150, for example, as shown in FIG. 4C. That is, the contact portion 150e is in contact with the circuit board 140 via a generally rectangular contact surface whose longitudinal direction is the width direction WD of the chip package 150 and whose width direction is the length direction LD of the chip package 150.

For example, as shown in FIG. 3B, the curable sealing material 141 is disposed around the base end 150b excluding one end of the base end 150b connected to the distal end 150a of the chip package 150, and is connected to the air passage AP. The space between the circuit chamber 118 and the circuit chamber 118 is sealed. Note that, as shown in FIG. 3C, the curable sealing material 141 covers the base end 150b, except for one end of the base end 150b connected to the tip 150a of the chip package 150 and the opposite end thereof. May be placed on both sides.

As shown in FIGS. 4C and 4D, the air passage AP between the bottom surface 150d of the chip package 150 and the circuit board 140 is connected to a curable sealant 141 disposed around the base end 150b of the chip package 150. It communicates with the measurement passage 132a. Here, the measurement passage 132a communicates with a second sub-passage groove 117b that forms a second sub-passage 132 that is a part of the sub-passage 130, as shown in FIGS. 3B and 3D. That is, the air passage AP between the bottom surface 150d of the chip package 150 and the circuit board 140 communicates between the curable sealing material 141 and the sub passage 130.

Further, as shown in FIG. 4D, the side surface of the base end portion 150b of the chip package 150 has an inclined surface 150f that slopes inward in the width direction WD toward the bottom surface 150d. The angle of inclination of the inclined surface 150f with respect to the mounting surface 140a of the circuit board 140 is, for example, 60 degrees or more and 80 degrees or less, and in this embodiment is about 70 degrees.

As shown in FIG. 3B or 3C, when the uncured curable sealing material 141 is applied around the proximal end portion 150b so as to cover all the connection terminals 153, as shown in FIG. 4D, the slanted surface 150f The curable sealing material 141 enters inside the base end portion 150b in the width direction WD along the line. Further, the uncured curable sealing material 141 seals between the circuit chamber 118 and the air passage AP in contact with the mounting surface 140a of the circuit board 140, but since it has viscosity, the chip package 150 The air hardly enters the air passage AP between the bottom surface 150d and the circuit board 140.

Further, in addition to the chip package 150, at least one of a temperature sensor 160, a pressure sensor 170, and a humidity sensor 180 is mounted on the circuit board 140 of the circuit board 140. In this embodiment, as shown in FIG. 4A, for example, a temperature sensor 160, a pressure sensor 170, and a humidity sensor 180 are mounted on the circuit board 140 of the circuit board 140, but any one of the sensors may be omitted. is also possible.

The temperature sensor 160 is, for example, a chip-type temperature sensor mounted on the circuit board 140. As shown in FIGS. 3B and 4A, for example, the temperature sensor 160 is disposed at the tip of the extending portion 140c of the circuit board 140 that extends toward the tip of the measuring portion 113 in the protruding direction (X-axis direction) of the measuring portion 113. has been done. The temperature sensor 160 is arranged in the temperature measurement passage 190 of the measurement unit 113, as shown in FIGS. 2A to 2C, and measures the temperature of the gas to be measured 2 taken into the temperature measurement passage 190 from the main passage 22.

The temperature measurement passage 190 has an entrance on the upstream side surface 113c of the measurement section 113, as shown in FIG. 2C, and has an entrance on both the front surface 113a and the back surface 113b of the measurement section 113, as shown in FIGS. It has an exit. The temperature measurement passage 190 takes in the gas to be measured 2 flowing through the main passage 22 from an inlet opening on the upstream side surface 113c of the measurement part 113, and takes in the gas 2 to be measured flowing through the main passage 22 from an outlet opening on the front side 113a and the back side 113b of the measurement part 113. Discharge to 22. With such a configuration, the heat dissipation of the temperature sensor 160 can be improved.

For example, the pressure sensor 170 is mounted on the mounting surface 140a of the circuit board 140 and is disposed within the circuit chamber 118. The circuit chamber 118 communicates with the folded portion of the second sub passage groove 117b that curves in a U-shape near the flange 111, that is, the folded portion of the second sub passage 132. This allows the pressure sensor 170 disposed in the circuit chamber 118 to measure the pressure of the gas to be measured 2 flowing through the main passage 22 .

For example, as shown in FIGS. 3B and 4A, the humidity sensor 180 is mounted on the mounting surface 140a of the circuit board 140, and is disposed in a partitioned area closer to the tip of the measurement unit 113 than the circuit chamber 118. Humidity sensor 180 detects the humidity of gas 2 to be measured.

Hereinafter, the operation of the physical quantity detection device 100 of this embodiment will be explained.

As described above, the physical quantity detection device 100 of this embodiment is a device that detects the physical quantity of the gas to be measured 2 flowing through the main passage 22. The physical quantity detection device 100 includes a sub passage 130 that takes in the gas to be measured 2 from the main passage 22 and detours it, and a flow rate sensor 151 that detects the flow rate of the gas to be measured 2 flowing through the sub passage 130. The physical quantity detection device 100 also includes a chip package 150 that drives a flow rate sensor 151, a circuit board 140 on which a connection terminal 153 of the chip package 150 is mounted, a circuit chamber 118 that accommodates the circuit board 140, and a connection terminal. 153. The chip package 150 has a base end 150b disposed in the circuit chamber 118 and provided with a connection terminal 153, a distal end 150a disposed in the sub passage 130 and provided with a flow rate sensor 151, and a circuit board 140. and a bottom surface 150d forming an air passage AP therebetween. This air passage AP communicates between the curable sealing material 141 and the sub passage 130.

With this configuration, when applying the curable sealing material 141 to seal the connection terminals 153 of the chip package 150, it is possible to suppress the generation of air pockets. More specifically, the chip package 150 includes an electronic component 152 for driving a flow rate sensor 151, and due to design constraints, the height in the normal direction of the mounting surface 140a of the circuit board 140 is higher than that of other sensors and electronic components. be higher than Then, as shown in FIG. 4D, the space formed between the connection terminals 153 of the chip package 150 and the circuit board 140 becomes larger. Therefore, when applying the uncured curable sealing material 141 to the connection terminal 153, air pockets are likely to occur around the connection terminal 153 or between the connection terminal 153 and the chip package 150.

Furthermore, there is a possibility that air may be trapped between the chip package 150 and the circuit board 140. If the curable encapsulant 141 is heated and cured in a state where such an air pocket is generated, the air in the air pocket may be removed due to expansion of the air or changes in the specific gravity of the curable encapsulant 141, for example. It may move through the cured curable sealant 141 . If such air reaches the surface of the curable sealant 141, there is a possibility that the connection terminal 153 may be exposed from the curable sealant 141. The connection terminals 153 exposed from the curable sealing material 141 are exposed to the gas to be measured 2 introduced into the circuit chamber 118 from the sub passage 130, and are corroded by water droplets, dust, and corrosive gas contained in the gas to be measured 2. Therefore, the reliability of the physical quantity detection device 100 may be reduced.

In contrast, in the physical quantity detection device 100 of this embodiment, the chip package 150 has the bottom surface 150d that forms the air passage AP between the chip package 150 and the circuit board 140, as described above. In other words, the bottom surface 150d of the chip package 150 is formed at a higher position than other parts of the chip package 150 that are in contact with the circuit board 140 in the height direction of the chip package 150, which is the normal direction of the circuit board 140. There is.

With such a configuration, an air passage AP that communicates between the curable sealing material 141 that seals the connection terminals 153 of the chip package 150 and the sub passage 130 can be formed. This air passage AP moves through the air between the curable encapsulant 141 and the chip package 150 or inside the curable encapsulant 141, for example, when the uncured curable encapsulant 141 is applied or heat cured. By allowing the air to escape to the sub passage 130, it is possible to suppress the generation of air pockets. As a result, the connection terminal 153 can be more reliably covered with the curable sealing material 141, and the reliability of the physical quantity detection device 100 can be improved.

Furthermore, in the physical quantity detection device 100 of this embodiment, the connection terminal 153 of the chip package 150 extends from the side surface of the base end 150b intersecting the bottom surface 150d to the width direction WD of the chip package 150 along the mounting surface 140a of the circuit board 140. It protrudes and is bent toward the circuit board 140. The side surface of the base end portion 150b of the chip package 150 has an inclined surface 150f that slopes inward in the width direction WD toward the bottom surface 150d.

With this configuration, a relatively large space is formed between the connecting terminal 153 that protrudes in the width direction from the side surface of the base end portion 150b of the chip package 150 and is bent toward the circuit board 140, and the side surface of the base end portion 150b. be done. However, the side surface of the base end portion 150b has an inclined surface 150f that slopes inward in the width direction WD toward the bottom surface 150d. Therefore, the uncured curable sealing material 141 applied between the connection terminal 153 and the inclined surface 150f is in contact with the inclined surface 150f, which has a larger area than the side surface parallel to the normal direction of the circuit board 140. , flows inward in the width direction WD toward the bottom surface 150d of the chip package 150. This promotes the spread of the uncured curable sealing material 141 on the chip package 150, making it possible to more effectively suppress the formation of air pockets.

Furthermore, in the physical quantity detection device 100 of this embodiment, the circuit board 140 has an extension portion 140b extending from the circuit chamber 118 to the sub passage 130 along the tip portion 150a of the chip package 150. Further, the chip package 150 has a contact portion 150e closer to the tip than the flow rate sensor 151 of the tip portion 150a. The extending portion 140b of the circuit board 140 and the contact portion 150e of the chip package 150 are in contact with each other.

With this configuration, the chip package 150 is mounted and fixed on the circuit board 140 with the plurality of connection terminals 153 of the base end 150b and the contact portion 150e of the tip end 150a in contact with the circuit board 140. Thereby, the chip package 150 can be stably fixed on the circuit board 140 with the air passage AP formed between the bottom surface 150d and the circuit board 140.

Furthermore, in the physical quantity detection device 100 of this embodiment, the connection terminal 153 is mounted on the circuit board 140 via the bonding material 142. With this configuration, the connection terminal 153 and the bonding material 142 can be covered with the curable sealing material 141 while suppressing the generation of air pockets. Therefore, corrosion of not only the connection terminal 153 but also the bonding material 142 can be prevented, and the reliability of the physical quantity detection device 100 can be further improved.

Furthermore, in the physical quantity detection device 100 of this embodiment, the curable sealant 141 is a silicone sealant. With this configuration, for example, compared to an epoxy-based sealant, it is possible to easily control physical properties such as the viscosity and thixotropic ratio of the uncured curable sealant 141, and the generation of air pockets can be more easily controlled. It can be suppressed reliably.

In addition, in the physical quantity detection device 100 of this embodiment, the curable sealing material 141 is attached to the base end portion 150b excluding one end of the base end portion 150b connected to the tip portion 150a of the chip package 150, as shown in FIG. 3B. , and seals between the air passage AP and the circuit chamber 118. This configuration prevents the measurement gas 2 containing water droplets, dust, corrosive gas, etc. from entering the circuit chamber 118 from the sub passage 130 via the air passage AP, thereby increasing the reliability of the physical quantity detection device 100. can be improved.

Furthermore, in the physical quantity detection device 100 of this embodiment, at least one of a temperature sensor 160, a pressure sensor 170, and a humidity sensor 180 is mounted on the mounting surface 140a of the circuit board 140.

With this configuration, by using the intake air as the gas to be measured 2, it is possible to detect not only the flow rate of the gas to be measured 2, but also physical quantities such as the temperature, pressure, and humidity of the gas to be measured 2, which are necessary for improving the efficiency of the internal combustion engine 10. I can do it. Therefore, the internal combustion engine control system 1 can be controlled more precisely by the control device 4, and the combustion efficiency of the internal combustion engine 10 can be improved.

Although the embodiment of the physical quantity detection device according to the present disclosure has been described above in detail using the drawings, the specific configuration is not limited to this embodiment, and design changes may be made within the scope of the gist of the present disclosure. etc., they are included in the present disclosure.

2 Gas to be measured 22 Main passage 100 Physical quantity detection device 118 Circuit chamber 130 Sub passage 140 Circuit board 140a Mounting surface 140b Extension part 141 Curable sealant 142 Bonding material 150 Chip package 150a Tip part 150b Base part 150d Bottom surface 150e Contact portion 150f Inclined surface 151 Flow rate sensor 153 Connection terminal 160 Temperature sensor 170 Pressure sensor 180 Humidity sensor AP Air passage WD Width direction

Claims (7)

A physical quantity detection device that detects a physical quantity of a gas to be measured flowing through a main passage,
A sub-passage for taking in and detouring the gas to be measured from the main passage, a flow rate sensor for detecting the flow rate of the gas to be measured flowing through the sub-passage, a chip package for driving the flow sensor, and a connection between the chip package. comprising a circuit board on which a terminal is mounted, a circuit chamber that accommodates the circuit board, and a curable sealant that seals the connection terminal,
The chip package has air between a base end portion disposed in the circuit chamber and provided with the connection terminal, a distal end portion disposed in the sub passageway and provided with the flow rate sensor, and the circuit board. a bottom surface forming a passage;
A physical quantity detection device, wherein the air passage communicates between the curable sealing material and the sub-passage. The connection terminal of the chip package protrudes from a side surface of the base end intersecting the bottom surface in the width direction of the chip package along the mounting surface of the circuit board and is bent toward the mounting surface,
The physical quantity detection device according to claim 1, wherein the side surface of the base end portion has an inclined surface that slopes inward in the width direction toward the bottom surface. The circuit board has an extension extending from the circuit chamber to the sub passage along the tip of the chip package,
The chip package has a contact portion closer to the tip than the flow rate sensor at the tip,
The physical quantity detection device according to claim 1, wherein the extending portion of the circuit board and the contact portion of the chip package are in contact with each other. The physical quantity detection device according to claim 1, wherein the connection terminal is mounted on the circuit board via a bonding material. The physical quantity detection device according to claim 1, wherein the curable sealant is a silicone sealant. The curable sealing material is disposed around the proximal end except for one end of the proximal end connected to the distal end, and seals between the air passage and the circuit chamber. The physical quantity detection device according to claim 1, characterized in that: The physical quantity detection device according to claim 1, wherein at least one of a temperature sensor, a pressure sensor, and a humidity sensor is mounted on the mounting surface of the circuit board.

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