JP5241669B2 - Flow measuring device - Google Patents

Description

  The present invention relates to a flow meter, and more particularly, to a flow rate measuring apparatus suitable for configuring an intake system of an automobile engine and detecting and controlling the intake air amount thereof.

  As a flow measurement device that measures the air flow rate, the heating resistor is controlled by heating and the flow rate is measured by the amount of heat released from the heating resistor, or the temperature sensitive resistor is placed near the heating resistor by controlling the heating resistor. A device that measures the flow rate according to the temperature change is known.

  The flow rate detection unit of the flow rate measuring device is disposed in a sub-passage formed of two or more parts. Therefore, the auxiliary passage shape is a part that greatly affects the flow rate measurement accuracy of the flow measuring device, and high assembly position accuracy is required when combining the auxiliary passage constituent members.

  In Patent Document 1, a flow measurement device that secures high assembly position accuracy by a press-fit pin structure that is crushed with respect to an insertion hole with respect to a structure in which the flow measurement device is configured by a plurality of structural members is a known technique. Are known.

JP 2002-62174 A

  Even in an environment where the ambient temperature is likely to change, such as an internal combustion engine, where the flow rate measuring device is a multiple structural member, it is less likely to be damaged by thermal deformation due to the length of the press-fit pin, and deformation or damage is less likely to occur in the manufacturing process There is a demand for a structure that can ensure the combined position accuracy of the structural members, that is, a structure that does not cause a change in output characteristics. Furthermore, the general technique of enlarging the pins can ensure the strength, but there is a problem that the insertion force becomes large in the assembly manufacturing process, and the combination cannot be easily performed.

  However, in the above-described known technology, there is a description about the long life of the aluminum wire and the assembly accuracy, but there is no description about the pin structure for securing the strength.

  An object of the present invention is to provide a highly reliable flow rate measuring apparatus that is excellent in ensuring positional accuracy and is less likely to cause characteristic errors.

  In order to achieve the above object, a flow rate measuring device according to the present invention is a flow rate measuring device having a sub-passage disposed in a main passage through which a fluid flows, wherein the sub-passage is formed by combining at least two parts. One of the at least two parts is provided with an insertion hole, and the other part is provided with a projection having a crushing margin and a pin having a projection smaller than the insertion hole. Two parts are combined by inserting the pin into the sub-passage to form the auxiliary passage.

  According to the present invention, not only the strength of the press-fit pin can be ensured, but also the positional accuracy of the structural member can be ensured, the output characteristics are hardly changed, and the assembling work in the manufacturing process is facilitated.

The member structure and press-fit pin shape detail drawing of the flow measuring device which is one Embodiment by a present Example. FIG. 2 is a detailed view of a press-fit pin shape when the arrangement of protrusions is changed in FIG. 1. FIG. 2 is a detailed view of a press-fit pin shape when a protrusion shape smaller than the insertion hole in FIG. 1 is crushed. The figure which shows the specific structural example of the internal combustion engine of an electronic fuel injection system using the flow measuring device of invention.

  A specific configuration according to the present invention is as follows.

  A sub-passage disposed in the main passage through which the fluid flows, and a flat plate member disposed in the sub-passage having a heating resistor pattern for measuring the flow rate on one surface side. Heating element in which the surface of the heating member provided with the pattern of the heating resistor is arranged along the flow of the fluid in the sub-passage, and the fluid flows between the surface of the flat plate member and the passage-forming surface of the sub-passage In the flow rate measuring device in which the back side fluid passage portion is configured between the pattern side fluid passage portion, the surface opposite to the surface of the flat plate member, and the passage forming surface of the sub passage, the sub passage includes at least 2 It is formed by combining two parts (members), and at least one of the two parts (members) has an insertion hole, and the other part (member) has a crushing projection. There is a pin to have, even less on the pin Also provided one or more of the insertion hole is smaller than the projection.

  At this time, the projections smaller than the insertion hole are preferably arranged alternately and radially from the crushing projection and the center of the insertion hole.

  Further, the projection smaller than the insertion hole may be provided with a projection portion that is crushed in a part in the longitudinal direction.

  Further, it is preferable to provide two or more insertion holes and pins.

  The insertion hole and the pin are preferably provided so as to surround the passage forming surface of the sub passage.

  The following embodiments of the present invention relate to a flow rate measuring device used to measure the flow rate of air sucked into an automobile internal combustion engine, and the press-fit pin structure according to the present invention can prevent deformation and breakage in heat and manufacturing processes. It is unlikely to occur, and provides a highly reliable structure while ensuring assembly position accuracy.

  Examples of the present invention will be specifically described.

  FIG. 1 is a front view (A) of a flow rate measuring device, a B detailed view (B) of a press-fit pin shape, and a C-C sectional view (C) showing an embodiment of the present invention.

  The structural member of the present embodiment will be described with reference to FIG.

  In the body 1 of the fluid passage constituting member that is the intake passage 12 of the intake air 11 shown in FIG. 1A, the housing frame 2 of the structural member of the flow rate measuring device constituting the auxiliary intake passage 13 is fixed to the fixing screw 3. Fixed.

  The electronic circuit 4, which is a flat plate member included in the housing frame 2, is provided with a heating resistor pattern for measuring the flow rate on one surface side so as to follow the flow of the fluid 14 flowing through the auxiliary intake passage 13. Placed in. In the present embodiment, the fluid 14 is air.

  Between the pattern surface of the heating resistor of the electronic circuit 4 and the passage forming surface of the auxiliary intake passage 13, the heating resistor pattern side fluid passage portion through which the fluid 14 flows is on the side opposite to the pattern surface of the heating resistor. A rear-side fluid passage portion is formed between the surface and the passage forming surface of the auxiliary intake passage 13. That is, the fluid 14 is configured to flow on both surfaces of the electronic circuit 4.

  The auxiliary intake passage forming surface of the auxiliary intake passage 13 is composed of the base 5 and the housing frame 2, and the base 5 is assembled with the insertion hole 21 and the housing frame 2 with the press-fit pin 22.

  The flow rate measuring device constituted by a plurality of structural members is assembled by inserting the press-fit pins 22 of the housing frame 2 into the insertion holes 21 of the base 5 in the manufacturing process. It is assumed that an excessive load is applied in the assembly process. Although the strength of the press-fit pin 22 can be ensured by increasing the thickness of the press-fit pin 22 or increasing the projection 23 having a crushing allowance, the insertion force due to the crushing allowance 23a is increased and the combination is easy. Disadvantages that cannot be considered. Therefore, the press-fit pin 22 needs to have a structure that can withstand the load. As shown in FIGS. 1B and 1C, the press-fit pin 22 of this embodiment is provided with a crushing projection 23 and a projection 24 smaller than the insertion hole 21, and the housing frame body in the insertion hole 21 of the base 5. When the second press-fit pin 22 is inserted and assembled, the projection 24 smaller than the insertion hole 21 can not only secure the strength of the press-fit pin 22 without increasing the insertion force, but also can maintain the accuracy of the combination position of the structural members. become. Further, the projection 23 having a crushing margin is less likely to be damaged due to thermal deformation even when the length of the press-fit pin 22 is increased even in a thermal environment in the engine room, that is, a flow measuring unit that measures an air flow rate is provided. The shape of the arranged sub passage can be accurately maintained.

  Note that the protrusion 24 is smaller than the insertion hole 21 that the length from the center of the press-fit pin 22 to the outermost peripheral portion (outermost peripheral surface) of the protrusion 24 is smaller than the radius of the insertion hole 21 or the center of the press-fit pin 22. This means that the length between the outermost peripheral portions (outermost peripheral surfaces) of the two projections 24 provided on both sides of the press-fit pin 22 is smaller than the diameter of the insertion hole 21. If the projection 23 having crushing allowance is similarly expressed, the projection 23 is larger than the insertion hole 21, and the length from the center of the press-fit pin 22 to the outermost peripheral portion (outermost peripheral surface) of the projection 23 is inserted. The length between the outermost peripheral portions (outermost peripheral surfaces) of the two protrusions 23 that are larger than the radius of the hole 21 or that are provided on both sides of the press-fit pin 22 across the center of the press-fit pin 22 is larger than the diameter of the insertion hole 21. Also means big.

  FIG. 2 shows a second embodiment. This embodiment is different from the embodiment shown in FIG. 1 in that the shape of the press-fit pin 22 is such that the projection 23 having a crushing margin larger than the insertion hole and the projection 24 smaller than the insertion hole 21 are radially formed from the center of the insertion hole 21. It is formed by alternately arranging alternately, and it can be expected that the stress is evenly distributed with respect to the load and thermal load received in the assembly process and the thermal environment for the press-fit pins 22. That is, it is possible to eliminate stress concentration portions that cause deformation or breakage. More specifically, the projections 23 having a crushing allowance are evenly arranged on the outer periphery of the press-fit pin 22 at an angular interval of 120 degrees in the circumferential direction. Are evenly arranged at an angular interval of 120 degrees. Further, the protrusions 24 are arranged in the middle of the two adjacent protrusions 23, and the protrusions 24 and the protrusions 23 are alternately and evenly arranged on the outer periphery of the press-fit pin 22 at an angular interval of 60 degrees in the circumferential direction.

  FIG. 3 shows a third embodiment. This embodiment is different from the embodiment shown in FIG. 1 in that the press-fit pin 22 is formed with a projection 25 having a crush allowance smaller than the projection 23 having a crush allowance, which is smaller than the insertion hole. The length in the longitudinal direction of the margin (the height direction of the press-fit pin 22) is shorter than the length in the longitudinal direction of the projection 23 having a collapse margin. The insertion force of the fitting component in the assembly process depends on the size of the outer shape of the projection 23 having a crushing margin, and this insertion force can be adjusted by the crushing amount of the projection 23 having a crushing margin, Increasing the thickness and thickness of the press-fit pin 22 is assumed to cause a short shot in resin molding. Therefore, by appropriately adjusting the length in the longitudinal direction of the crushing margin 25a of the projection 25 having a crushing margin smaller than the insertion hole, an insertion force suitable for the purpose can be ensured.

  At least one or more press-fit pins 22 and insertion holes 21 each having a projection 23 having a crushing margin and a projection 24 smaller than the insertion hole or a projection 25 having a crushing margin smaller than the insertion hole may be provided. By providing a plurality of locations so as to surround the sub-passage shape surface of the device, a flow rate measuring unit for measuring the air flow rate is arranged particularly by surrounding the important part that determines the flow rate output characteristics of the flow rate measuring device. The sub passage shape can be accurately maintained.

  FIG. 4 is a diagram showing a specific configuration example of an operation control system for an internal combustion engine of an electronic fuel injection system using the flow rate measuring device 101 of the present invention.

  In FIG. 4, an intake air 11 sucked from an air cleaner 100 is an intake having a body 1, an intake duct 103, a throttle body 104, and an injector (fuel injection valve) 105 to which fuel is supplied. It is sucked into the engine cylinder 107 through the manifold 106. The gas 108 generated in the engine cylinder 107 is discharged to the outside through the exhaust manifold 109. An air flow rate signal output from the flow rate measuring device 101, an intake air temperature signal, a throttle valve angle signal output from the throttle angle sensor 111, an oxygen concentration signal output from an oxygen concentration meter 112 provided in the exhaust manifold 109, and An engine speed signal or the like output from the engine speed meter 113 is supplied to the control unit 114. The control unit 114 sequentially calculates the supplied signal to obtain an optimal fuel injection amount and an idle air control valve opening, and controls the injector 105 and the idle air control valve 115 using these values. If the flow rate measuring device 101 according to the present invention is used in an internal combustion engine of an electronic fuel injection system, an accurate flow rate can be measured and accurate operation control of the internal combustion engine can be performed.

  The following effects are obtained by the embodiment described above.

  Flow measurement comprising a sub-passage disposed in the main passage through which fluid flows, and a flat plate member disposed in the sub-passage provided with a heating resistor pattern on one surface side for measuring the flow rate In the apparatus, the sub-passage is formed by combining at least two parts (members), and one of the at least two parts (members) has an insertion hole and the other part (member). Is provided with a pin having a projection with a crushing allowance, and by providing at least one projection smaller than the insertion hole on this pin, not only can the strength of the pin be secured, but also the structural member Position accuracy can be ensured, output characteristics do not easily change, and the assembly work in the manufacturing process is facilitated.

  Flow measurement comprising a sub-passage disposed in the main passage through which fluid flows, and a flat plate member disposed in the sub-passage provided with a heating resistor pattern on one surface side for measuring the flow rate In the apparatus, the sub-passage is formed by combining at least two parts (members), and one of the at least two parts (members) has an insertion hole and the other part (member). Is provided with a pin having a projection with a crushing margin, and this pin is provided with at least one projection smaller than the insertion hole, and the projection smaller than the insertion hole has a projection with a crushing margin and an insertion hole. Evenly, even if an external force is applied, the stress value at the stress concentration part can be reduced as much as possible, the position accuracy of the structural member can be ensured, and the output characteristics do not easily change. It is effective to facilitate the assembly work in the manufacturing process.

  Flow measurement comprising a sub-passage disposed in the main passage through which fluid flows, and a flat plate member disposed in the sub-passage provided with a heating resistor pattern on one surface side for measuring the flow rate In the apparatus, the sub-passage is formed by combining at least two parts (members), and one of the at least two parts (members) has an insertion hole and the other part (member). Is provided with a pin having a projection with a crushing allowance, and at least one projection smaller than the insertion hole is provided on the pin, and the projection smaller than the insertion hole is crushed into a part in the longitudinal direction. By providing the protrusions having a length, adjusting the length has an effect of ensuring the pull-out strength of the pin after assembly without sacrificing the ease of the assembly operation in the manufacturing process.

  By providing two or more combinations of the insertion hole and the pin having the projection described above, there is an effect that the positional accuracy of the further structural member can be ensured.

  By providing a plurality of combinations of the aforementioned insertion holes and pins having protrusions so as to surround the passage formation surface of the sub passage, it becomes possible to form the shape of the sub passage that affects the change in output characteristics, and the characteristic error will be reduced. It is less likely to occur and increases the reliability.

  By using the flow rate measuring device that facilitates assembly work in the manufacturing process and hardly changes in output characteristics, a highly reliable operation control system for an internal combustion engine can be provided.

  Engine control in a vehicle is the main use, but it can be used for control using a diesel engine such as a ship or a generator.

1 Body 2 Housing frame 3 Fixing screw 4 Electronic circuit (circuit board)
5 Base 11 Intake Air 12 Intake Passage 13 Sub-Intake Passage 14 Fluid 21 Insertion Hole 22 Press-fit Pin 23 Crushing Protrusion 24 Protrusion Smaller than Insertion Hole 25 Protrusion with Crushing Allowance Smaller than Insertion Hole 100 Air Cleaner 101 Flow Measuring Device 103 Intake duct 104 Throttle body 105 Injector 106 Intake manifold 107 Engine cylinder 108 Gas 109 Exhaust manifold 111 Throttle angle sensor 112 Oxygen concentration meter 113 Engine tachometer 114 Control unit 115 Idle air control valve

Claims (4)

A flow rate measuring device having a sub-passage disposed in a main passage through which a fluid flows ,
The auxiliary passage is formed by combining at least two parts;
One of the at least two parts is provided with an insertion hole, and the other part is provided with a crushing projection and a pin having a projection smaller than the insertion hole,
In the flow rate measuring apparatus in which two parts are combined by inserting the pin into the insertion hole, and the auxiliary passage is formed ,
A flow rate measuring apparatus, wherein a projection having a crushing margin is provided in a part of the projection in a longitudinal direction smaller than the insertion hole.
The flow measurement device according to claim 1,
The projection smaller than the insertion hole and the projection with crushing allowance are formed radially from the center of the pin, respectively, and the projection smaller than the insertion hole and the projection with crushing allowance are of the pin A flow rate measuring device, which is alternately and evenly arranged in the circumferential direction.
The flow rate measuring device according to claim 1 or 2 ,
A flow rate measuring apparatus comprising two or more pins and the insertion holes.
The flow rate measuring device according to claim 3 ,
The flow rate measuring device according to claim 1, wherein the pin and the insertion hole are provided so as to surround the passage forming surface of the sub passage.

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