Physical quantity detection device
By introducing a positioning structure consisting of a pin and a fitting part into the physical quantity detection device, the problem of low positioning accuracy between the shell and the cover is solved, and the consistency of the flow path and the detection accuracy are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ASTEMO LTD
- Filing Date
- 2020-10-27
- Publication Date
- 2026-05-26
Smart Images
Figure CN114729829B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to devices for detecting physical quantities. Background Technology
[0002] Inventions related to physical quantity detection devices suitable for detecting the flow rate and pressure of air drawn into an internal combustion engine of a car have been known for a long time (see Patent Document 1 below). The conventional physical quantity detection device described in Patent Document 1 includes a detection element for detecting physical quantities, an electronic circuit electrically connected to the detection element, and a housing for housing and holding the electronic circuit (see claim 1 of that document, etc.).
[0003] This conventional physical quantity detection device has a connector and a connector housing on the aforementioned housing. The connector connects the aforementioned electronic circuit to an external device, and the connector housing surrounds the connector, which protrudes outward from the housing. Furthermore, this conventional physical quantity detection device is characterized in that a portion of the housing frame, where the connector communicates internally and externally with the electronic circuit side and the connector housing side, is provided with a groove that exposes a portion of the connector.
[0004] With this configuration, the connector or support exposed in the slot can be used as an adjustment terminal for obtaining the output characteristics during adjustment, making the adjustment operation easy and simplifying the manufacturing process (see lines 3-5 on page 3 of this document).
[0005] Furthermore, a cover is fixed to one side of the aforementioned housing, and a metal base is installed on the other side of the housing and the open side of the secondary passageway. The base is positioned by pressing protrusions on the secondary passageway and the housing into recesses on the base, and is then fixed in place using adhesive (see pages 8, lines 9-17 of this document). Figure 2 wait).
[0006] Existing technical documents
[0007] Patent documents
[0008] Patent Document 1: International Publication No. 2002 / 066937 Summary of the Invention
[0009] The problem the invention aims to solve
[0010] In the aforementioned conventional physical quantity measuring devices, as the number of protrusions and recesses used for positioning the base and housing increases, the assembly tolerances of the base and housing increase, and the positioning accuracy decreases. Therefore, the size and shape of the secondary passageway between the base and housing for the gas flow of the measured object in each physical quantity measuring device exhibit individual differences, potentially affecting the accuracy of the physical quantity measurement.
[0011] This disclosure provides a physical quantity detection device that can improve the measurement accuracy of physical quantities compared to the past.
[0012] Technical means to solve the problem
[0013] One aspect disclosed herein is a physical quantity detection device comprising: a detection element for detecting a physical quantity; a circuit board on which the detection element is mounted; a housing for housing the circuit board; and a cover fixed to the housing for defining a flow path for the detection element. The housing and the cover have positioning portions, each having a pin extending along the thickness direction of the circuit board and a fitting portion for engaging the top end of the pin to position the housing and the cover. The pin has a locking portion that faces a locking surface of the circuit board along the thickness direction, thereby restricting movement of the circuit board along its surface and back surfaces.
[0014] The effects of the invention
[0015] According to the above-described embodiment disclosed herein, a physical quantity detection device can be provided that improves the positioning accuracy of the housing and cover, reduces individual differences in the flow of fluid passing through the flow path in which the detection element is configured, and improves the measurement accuracy of the physical quantity by the detection element compared to the past. Attached Figure Description
[0016] Figure 1 This is a system diagram illustrating an example of an internal combustion engine control system equipped with a physical quantity detection device.
[0017] Figure 2 This is a schematic cross-sectional view of Embodiment 1 of the physical quantity detection device disclosed herein.
[0018] Figure 3 for Figure 2 The rear view of the physical quantity detection device after the cover has been removed.
[0019] Figure 4A To constitute Figure 2 An example of the shape of the pin in the positioning part of the physical quantity detection device shown.
[0020] Figure 4B To constitute Figure 2 An example of the shape of the pin in the positioning part of the physical quantity detection device shown.
[0021] Figure 4C To constitute Figure 2 An example of the shape of the pin in the positioning part of the physical quantity detection device shown.
[0022] Figure 4D To constitute Figure 2 An example of the shape of the pin in the positioning part of the physical quantity detection device shown.
[0023] Figure 4E To constitute Figure 2 An example of the shape of the pin in the positioning part of the physical quantity detection device shown.
[0024] Figure 5 for Figure 3 An example of the configuration of the pin and the through hole of the circuit board in the physical quantity detection device shown.
[0025] Figure 6 This is a schematic cross-sectional view of Embodiment 2 of the physical quantity detection device disclosed herein. Detailed Implementation
[0026] Hereinafter, with reference to the accompanying drawings, embodiments of the physical quantity detection device disclosed herein will be described.
[0027] [Implementation Method 1]
[0028] Figure 1 This is a system diagram illustrating an example of an internal combustion engine control system 1 using the electronic fuel injection method of the physical quantity detection device 20 of this embodiment. In the internal combustion engine control system 1, intake air, which is the gas to be measured, is drawn in from the air filter 21 according to the operation of the internal combustion engine 10, which includes an engine cylinder 11 and an engine piston 12. The intake air is guided to the combustion chamber of the engine cylinder 11 via the intake manifold 22, the throttle body 23, and the intake manifold 24, which serve as the main passage 22.
[0029] The physical quantity of the intake air (gas 2) guided into the combustion chamber is measured by the physical quantity detection device 20. Further, fuel is supplied from the fuel injection valve 14 based on the physical quantity measured by the physical quantity detection device 20, and is guided into the combustion chamber as a mixture with the intake air. In this embodiment, the fuel injection valve 14 is located at the intake port of the internal combustion engine 10. The fuel injected into the intake port mixes with the intake air, and this fuel-air mixture is guided into the combustion chamber via the intake valve 15. The mixture guided into the combustion chamber is ignited by the spark plug 13 and burns explosively to generate mechanical energy.
[0030] The combusted gases are guided from the exhaust valve 16 to the exhaust pipe and discharged outside the vehicle as exhaust gas 3. The flow rate of the intake air (measured gas 2) guided to the combustion chamber is controlled by the throttle valve 25, the opening of which changes according to the operation of the accelerator pedal. Furthermore, the fuel supply is controlled based on the flow rate of the intake air guided to the combustion chamber. By controlling the flow rate of the intake air guided to the combustion chamber through the control of the throttle valve 25, the mechanical energy produced by the internal combustion engine 10 can be controlled.
[0031] The physical quantity detection device 20 measures the physical quantities such as flow rate, temperature, humidity, and pressure of the intake air (the gas to be measured) introduced through the air filter 21 and flowing in the main passage 22. The physical quantity detection device 20 outputs an electrical signal corresponding to the physical quantity of the intake air. The output signal of the physical quantity detection device 20 is input to the control device 4.
[0032] Furthermore, the output of the throttle angle sensor 26, which measures the opening of the throttle valve 25, is input to the control unit 4. Additionally, the output of the rotation angle sensor 17 is input to the control unit 4 to measure the position and state of the engine piston 12, intake valve 15, and exhaust valve 16 of the internal combustion engine 10, as well as the engine speed. The output of the oxygen sensor 28 is input to the control unit 4 to measure the fuel-air mixture ratio based on the state of the exhaust gas 3.
[0033] The control unit 4 calculates the fuel injection quantity and ignition timing based on the output of the physical quantity detection device 20 (i.e., the physical quantity of the intake air) and the engine speed of the internal combustion engine 10 measured based on the output of the rotation angle sensor 17. Based on these calculation results, it controls the amount of fuel supplied from the fuel injection valve 14 and the ignition timing by the spark plug 13. In practice, the fuel supply quantity and ignition timing are also meticulously controlled based on the temperature measured by the physical quantity detection device 20, the change in throttle angle, the change in engine speed, and the air-fuel ratio measured by the oxygen sensor 28.
[0034] The control device 4 also uses the idle air control valve 27 to control the amount of air bypassing the throttle valve 25 when the internal combustion engine 10 is idling, thereby controlling the speed of the internal combustion engine 10 in the idling state.
[0035] The main control quantities of the internal combustion engine 10, namely fuel supply and ignition timing, are calculated based on the output of the physical quantity detection device 20 as the main parameters. Therefore, improving the measurement accuracy, suppressing time-varying changes, and improving the reliability of the physical quantity detection device 20 are important for improving the control accuracy and ensuring the reliability of the vehicle.
[0036] In recent years, expectations for fuel efficiency and exhaust purification in vehicles have been particularly high. To meet these expectations, improving the accuracy of measuring the physical quantities of the measured gas 2 (i.e., the intake air) by the physical quantity detection device 20 is extremely important. Furthermore, maintaining high reliability of the physical quantity detection device 20 is also crucial.
[0037] As will be explained below, the physical quantity detection device 20 installed in the vehicle does not merely solve the problems described in the "Problems to be Solved by the Invention" section and achieve the effects described in the "Effects of the Invention" section. As will be explained below, the physical quantity detection device 20 fully considers the various problems mentioned above, solves the various problems sought to be solved in the product, and achieves various effects. The specific problems solved by the physical quantity detection device 20 and the specific effects achieved will be explained in the following description related to the embodiments.
[0038] Figure 2 for Figure 1 A schematic cross-sectional view of the physical quantity detection device 20 shown. Figure 3 To indicate Figure 2 A rear view of an example of the physical quantity detection device 20 after the cover 202 has been removed.
[0039] The physical quantity detection device 20 includes a housing 201 and a cover 202 mounted on the housing 201. The housing 201 is constructed, for example, by injection molding of a synthetic resin material. The cover 202 is constructed, for example, by a plate-like member, or by injection molding of a synthetic resin material, wherein the plate-like member is made of a conductive material such as aluminum alloy. The cover 202 is formed as a thin plate and has a wide and flat cooling surface.
[0040] The housing 201 has a flange 201f, a connector 201c, and a measuring part 201m. The flange 201f is fixed to the air intake pipe body, which serves as the main passage 22. The connector 201c protrudes from the flange 201f and protrudes from the air intake pipe body to the outside for electrical connection with external devices. The measuring part 201m extends from the flange 201f toward the center of the main passage 22.
[0041] Flange 201f, for example, has a generally rectangular shape in plan view, consisting of a specified plate thickness, and has through holes at the corners. Flange 201f is fixed to the main passage 22, for example, by inserting a fixing screw through the through hole at the corner and screwing it into the screw hole of the main passage 22.
[0042] Connector 201c, for example, has four external terminals and correction terminals internally. The external terminals are for outputting the measurement results of the physical quantity detection device 20, such as flow rate and temperature, and are also power supply terminals for supplying DC power to the physical quantity detection device 20 for operation. The correction terminals are used to perform measurements on the manufactured physical quantity detection device 20 to obtain correction values related to each physical quantity detection device 20 and store the correction values in the memory inside the physical quantity detection device 20.
[0043] The measuring section 201m is a thin, elongated plate-like shape extending from the flange 201f toward the center of the main passage 22. It has a wide back surface 221 and a wide front surface 222, as well as a pair of narrow side surfaces, namely the upstream end face 223 and the downstream end face 224. With the physical quantity detection device 20 installed on the main passage 22, the measuring section 201m protrudes from the inner wall of the main passage 22 toward the central axis 22a of the main passage 22, and the back surface 221 and the front surface 222 are arranged parallel to the central axis 22a of the main passage 22.
[0044] Furthermore, among the narrow upstream end face 223 and downstream end face 224 of the measuring unit 201m, the upstream end face 223 on the width side of the measuring unit 201m is arranged facing the upstream side of the main passage 22, and the downstream end face 224 on the other side of the width direction of the measuring unit 201m is arranged facing the downstream side of the main passage 22.
[0045] Furthermore, the measuring unit 201m has an inlet 231 on the upstream end face 223 of its top end portion 201t, opposite to the flange 201f located at the base end. The inlet 231 is used to introduce a portion of the gas to be measured, such as air, into the measuring unit 201m via a secondary passage 234. Additionally, the measuring unit 201m has a first outlet 232 and a second outlet 233 on the downstream end face 224 of its top end portion 201t, opposite to the upstream end face 223. The first outlet 232 and the second outlet 233 are used to return the gas to be measured 2 introduced into the secondary passage 234 of the measuring unit 201m to the main passage 22.
[0046] In the physical quantity detection device 20, the inlet 231 of the secondary passage 234 is located at the top end 201t of the measuring section 201m, which extends from the flange 201f toward the center of the main passage 22. Therefore, the physical quantity detection device 20 can introduce gas from the portion near the center, away from the inner wall surface, rather than gas near the inner wall surface of the main passage 22, into the secondary passage. As a result, the physical quantity detection device 20 can measure the flow rate of gas from the portion far from the inner wall surface of the main passage 22, thereby suppressing the reduction in measurement accuracy caused by factors such as heat.
[0047] The measuring section 201m is provided with a sub-passage groove 250 for forming a sub-passage 234 and a circuit chamber 235 for housing a circuit board 207. The circuit chamber 235 and the sub-passage groove 250 are recessed in one side of the plate-shaped measuring section 201m in the thickness direction. The circuit chamber 235 is located upstream of the flow direction of the measured gas 2 in the main passage 22, and the sub-passage 234 is located downstream of the flow direction of the measured gas 2 in the main passage 22 relative to the circuit chamber 235.
[0048] The secondary passageway 250, together with the cover 202, defines the secondary passageway 234. The secondary passageway 250 has a first secondary passageway 251 and a second secondary passageway 252 that branches off from the first secondary passageway 251.
[0049] The first secondary passageway 251 is formed to span between the inlet 231 opened on the upstream end face 223 of the measuring section 201m and the first outlet 232 opened on the downstream end face 224 of the measuring section 201m, and extends along the width direction of the measuring section 201m. The first secondary passageway 251 forms a first secondary passageway 234a between itself and the cover 202, extending from the inlet 231 along the central axis 22a of the main passageway 22 to the first outlet 232.
[0050] The second auxiliary passageway 252 branches off from the first auxiliary passageway 251 along the length of the measuring section 201m towards the flange 201f and extends in a direction approximately orthogonal to the central axis 22a of the main passageway 22. Further, the second auxiliary passageway 252 bends back towards the top end 201t near the flange 201f of the measuring section 201m, for example, in a U-shape or arc shape, and extends along the length of the measuring section 201m, that is, in a direction orthogonal to the central axis 22a of the main passageway 22. The second auxiliary passageway 252 finally bends towards the downstream end face 224 of the measuring section 201m, for example, in an arc shape, and connects to the second outlet 233.
[0051] The second outlet 233 is opened downstream of the flow direction of the measured gas 2 within the main passage 22. The second outlet 233 has a larger opening area than the first outlet 232 and is formed at the base end of the measuring section 201m in the length direction relative to the first outlet 232. The second secondary passage groove 252 forms a second secondary passage 234b between itself and the cover 202, branching from the first secondary passage 234a toward the flange 201f and reaching the second outlet 233.
[0052] The first secondary passage 234a introduces the measured gas 2 flowing in the main passage 22 through the inlet 231 and returns the introduced measured gas 2 to the main passage 22 from the first outlet 232. The first secondary passage 234a has a branch 236 between the inlet 231 and the first outlet 232. The measured gas 2 flowing in the main passage 22 is introduced into the first secondary passage 234a from the inlet 231 in a downstream direction, flows towards the first outlet 232 in the first secondary passage 234a, and flows into the second secondary passage 234b from the branch 236.
[0053] The second auxiliary passage 234b allows the gas 2 being measured, which branches off from the first auxiliary passage 234a, to pass through and be returned to the main passage 22 from the second outlet 233. The second auxiliary passage 234b has a reciprocating path along the length of the measuring section 201m. More specifically, the second auxiliary passage 234b has, for example, a straight upstream section 237, an arc-shaped or U-shaped bend 238, and a straight downstream section 239.
[0054] The physical quantity detection device 20 is equipped, for example, with a flow detection unit 205 disposed in the upstream portion 237 of the second sub-passage 234b as a detection element for detecting physical quantities. More specifically, in the upstream portion 237 of the second sub-passage 234b, the flow detection unit 205 is disposed in the middle portion between the first sub-passage 234a and the bend 238. By having the aforementioned bend shape, the second sub-passage 234b can ensure a longer passage length, thereby reducing the impact on the flow detection unit 205 in the event of pulsation of the measured gas 2 in the main passage 22.
[0055] The circuit board 207 is housed in a circuit chamber 235 located on one side of the measuring section 201m in the width direction. The circuit board 207 has, for example, a generally L-shaped shape, that is, it extends along the length direction of the measuring section 201m, and the end of the measuring section 201m on the flange 201f side extends along the width direction of the measuring section 201m.
[0056] An intake air temperature sensor 203, a pressure sensor 204, a humidity sensor 206, and a chip package 208 with a flow detection unit 205 are mounted on the surface of the circuit board 207. That is, the physical quantity detection device 20 is equipped with, for example, an intake air temperature sensor 203, a pressure sensor 204, a flow detection unit 205, and a humidity sensor 206 as elements for detecting physical quantities, namely temperature, pressure, flow rate, and humidity.
[0057] An intake air temperature sensor 203 is disposed, for example, within a temperature detection passage, to measure the temperature of the gas 2 being measured flowing through the temperature detection passage. The temperature detection passage has, for example, an inlet near an inlet 231 located on the upstream end face 223 of the measuring section 201m, and outlets on both the back side 221 of the measuring section 201m and the cover 202 mounted on the front side 222.
[0058] Pressure sensor 204 measures the pressure of the gas 2 being measured within circuit chamber 235, and humidity sensor 206 measures the humidity of the gas 2 being measured within circuit chamber 235. Circuit chamber 235 is located between housing 201 and cover 202, and is connected to second secondary passage 234b via pressure inlet flow path. Gas 2 being measured flows into the second secondary passage 234b via pressure inlet flow path.
[0059] The flow detection unit 205 measures, for example, the flow rate of the gas to be measured 2 flowing in the flow path D1 between the recess of the chip package 208 and the circuit board 207. More specifically, the gas to be measured 2 flows in the flow path D1 between the recess of the chip package 208 and the circuit board 207, the flow path D2 between the second secondary passage groove 252 of the housing 201 and the circuit board 207, and the flow path D3 between the chip package 208 and the cover 202.
[0060] Furthermore, the flow rate of one of the physical quantities of the gas to be measured 2 flowing in the flow path D1 between the recess of the chip package 208 and the circuit board 207 is detected by the flow rate detection unit 205, one of the detection elements in the physical quantity detection device 20 of this embodiment. The flow rate detection unit 205 is, for example, a thermal air flow meter, that is, it has a pair of temperature-sensing resistors on both sides of the heating resistor in the flow direction of the gas to be measured 2, and the air flow rate is determined based on the temperature difference between the pair of temperature-sensing resistors.
[0061] In the physical quantity detection device 20, if the positioning accuracy of the housing 201 and the cover 202, and the positioning accuracy of the housing 201 and the circuit board 207 decrease, there is a concern that the size and shape of the flow paths D2 and D3 through which the gas to be measured 2 passes will vary. As a result, the flow of the gas to be measured 2 through the flow path D1 facing the detection element, i.e., the flow detection unit 205, will vary, thus affecting the accuracy of the flow rate measurement as a physical quantity.
[0062] Therefore, in the physical quantity detection device 20, in order to improve the measurement accuracy of physical quantities compared to the past, it is important to improve the positioning accuracy of the housing 201 and the cover 202, and the positioning accuracy of the housing 201 and the circuit board 207. The following is a detailed description of the features of the physical quantity detection device 20 of this embodiment, which is configured to solve such problems. The physical quantity detection device 20 of this embodiment is mainly characterized by the following configuration.
[0063] As described above, the physical quantity detection device 20 includes various detection elements for detecting physical quantities and a circuit board 207 on which these detection elements are mounted. Furthermore, the physical quantity detection device 20 includes a housing 201 that houses the circuit board 207 and a cover 202 fixed to the housing 201 that defines a flow path, i.e., a second auxiliary passage 234b, for the flow detection unit 205, which is one of the detection elements. Further, the housing 201 and the cover 202 have a positioning portion P. This positioning portion P has a pin P1 extending along the thickness direction Dt of the circuit board 207 and a fitting portion P2 for engaging the top end portion P11 of the pin P1 to position the housing 201 and the cover 202. The pin P1 also has a locking portion P12, which faces the locking surface 207f of the circuit board 207 along the thickness direction Dt, restricting the movement of the circuit board 207 along the surface direction Df of its surface and back surface.
[0064] More specifically, in Figure 2 and Figure 3 In the example shown, the pin P1 constituting the positioning part P is provided in the housing 201, for example. The pin P1 is injection molded as part of the housing 201, and is integrally formed with the housing 201 from the same material as the housing 201. Alternatively, the pin P1 may be a different component from the housing 201, which can be mounted on the housing 201.
[0065] Furthermore, the pin P1 can be configured as a column with any cross-sectional shape, such as a cylinder, elliptical column, quadrilateral column, or polygonal column. The locking portion P12 of the pin P1 is provided, for example, at the base end of the pin P1 opposite to the top end P11 in the protruding direction. The outer peripheral surface of the locking portion P12 of the pin P1 is configured to be approximately parallel to the thickness direction Dt of the circuit board 207. Thus, the outer peripheral surface of the locking portion P12 is opposite to the locking surface 207f of the circuit board 207, which is approximately parallel to the thickness direction Dt, in the surface direction Df of the circuit board 207.
[0066] The locking surface 207f of the circuit board 207 is, for example, the inner peripheral surface or inner wall surface of the through hole 207h provided on the circuit board 207. Alternatively, the locking surface 207f of the circuit board 207 may also be, for example, the outer peripheral surface along the outer edge of the circuit board 207, or the wall surface of the notch provided on the outer edge of the circuit board 207. The locking surface 207f of the circuit board 207 is at least partially in contact with the locking portion P12 of the pin P1, which is opposite to the pin P1 in the surface direction Df of the circuit board 207, or they are opposite each other with a small gap. Here, the small gap between the locking surface 207f and the locking portion P12 is, for example, the dimensional tolerance that allows the locking portion P12 of the pin P1 to be inserted into the through hole 207h of the circuit board 207.
[0067] exist Figure 2 In the example shown, the fitting portion P2 constituting the positioning portion P is, for example, provided on the cover 202. The fitting portion P2 is, for example, forged, cast, or injection molded as part of the housing 201, and is integrally formed with the cover 202 from the same material. Furthermore, the fitting portion P2 may also be a different component from the cover 202, which can be mounted on the cover 202. Additionally, in Figure 2 and Figure 3 In the example shown, the outer diameter of the locking part P12 of the pin P1 is larger than the outer diameter of the top part P11.
[0068] In addition, Figure 2 and Figure 3 In the example shown, there are two pins P1 and two fitting parts P2 constituting the positioning part P. Figure 2 In the schematic cross-sectional view, for convenience, the two pins P1 and two fitting parts P2 of the flow detection unit 205 and the positioning unit P are shown, but if... Figure 3 As shown, they may not exist on the same cross section. In addition, from the viewpoint of improving the positioning accuracy of the housing 201, cover 202 and circuit board 207 and reducing the space for setting pin P1, the number of pins P1 can be set to, for example, more than 1 and less than 3.
[0069] In addition, Figure 2 In the example shown, the fitting portion P2 constituting the positioning portion P is configured as a concave shape to fit the top end P11 of the pin P1, and has an inner wall surface P21 that is opposite to the outer peripheral surface of the pin P1 in the surface direction Df of the circuit board 207 to restrict the movement of the pin P1. The inner wall surface P21 of the fitting portion P2 is configured as a bottomed cylindrical shape with any cross-sectional shape, such as a cylinder, a quadrilateral cylinder, or a polygonal cylinder, corresponding to the shape of the top end P11 of the pin P1, and surrounds the entire circumference of the top end P11 of the pin P1.
[0070] Figures 4A to 4EAn example of the shape of the top part P11 of the pin P1 that constitutes the positioning part P and the locking part P12 is shown respectively. Figures 4A to 4E In the figures, the left figure is a top view of the top of pin P1 as seen from the protruding direction of pin P1, and the right figure is a side view of pin P1 as seen from a direction orthogonal to the protruding direction of pin P1.
[0071] exist Figures 4A to 4E In the example shown, the outer diameter OD2 of the locking portion P12 of the pin P1 is larger than the outer diameter OD1 of the top portion P11, forming a radial step difference in the pin P1 between the top portion P11 and the locking portion P12. Furthermore, the top portion P11 and the locking portion P12 of the pin P1 can also have the same outer diameter, or the outer diameter can gradually decrease in a tapered shape from the locking portion P12 towards the top of the top portion P11.
[0072] exist Figure 4A In the example shown, the top portion P11 and the locking portion P12 of the pin P1 are both formed into cylindrical shapes. In this case, the fitting portion P2, which is fitted to the top portion P11 of the pin P1, is set as a bottomed cylindrical concave shape corresponding to the shape of the top portion P11. Furthermore, the through hole 207h of the circuit board 207 through which the locking portion P12 of the pin P1 is inserted is also formed as a cavity or hole with a circular opening and a cylindrical inner wall surface, i.e., a locking surface 207f, corresponding to the shape of the locking portion P12.
[0073] exist Figure 4B In the example shown, the top end P11 of the pin P1 is cylindrical, and the locking portion P12 has multiple ribs P121. More specifically, the locking portion P12 has a cylindrical shaft P122 with the same outer diameter OD1 as the top end P11, and multiple ribs P121 protruding radially from the outer peripheral surface of the shaft P122 toward the locking surface 207f of the circuit board 207 along the pin P1. Furthermore, the number of ribs P121 in the locking portion P12 is not particularly limited; for example, it can be 2, 3, 4, or 5 or more. In this example, Figure 2 The fitting portion P2 shown is also set as a bottomed cylindrical concave shape corresponding to the shape of the top portion P11, and the through hole 207h of the circuit board 207 is also formed as a cavity or hole shape corresponding to the shape of the locking portion P12.
[0074] exist Figure 4C In the example shown, the top portion P11 of the pin P1 has multiple ribs P111, and the locking portion P12 is cylindrical. More specifically, the top portion P11 has a cylindrical shaft portion P112 and multiple ribs P111 protruding radially from the outer peripheral surface of the shaft portion P112 toward the inner wall surface P21 of the fitting portion P2. Furthermore, the number of ribs P111 in the top portion P11 is not particularly limited; for example, it can be 2, 3, 4, or 5 or more. In this example, Figure 2 The fitting portion P2 shown is also set as a bottomed cylindrical concave shape corresponding to the shape of the top portion P11, and the through hole 207h of the circuit board 207 is also formed as a cavity or hole shape corresponding to the shape of the locking portion P12.
[0075] exist Figure 4D In the example shown, the top portion P11 and the locking portion P12 of the pin P1 each have ribs P111 and P121, respectively. More specifically, the top portion P11 and the locking portion P12 each have a shaft portion P112 and a shaft portion P122 with the same outer diameter. Furthermore, the top portion P11 has multiple ribs P111 protruding radially from the outer circumferential surface of the shaft portion P112 along the pin P1, and the locking portion P12 has multiple ribs P121 protruding radially from the outer circumferential surface of the shaft portion P122 along the pin P1. Additionally, the number of ribs P111 in the top portion P11 and the number of ribs P121 in the locking portion P12 may be the same or different. In this example, Figure 2 The fitting portion P2 shown is also set as a bottomed cylindrical concave shape corresponding to the shape of the top portion P11, and the through hole 207h of the circuit board 207 is also formed as a cavity or hole shape corresponding to the shape of the locking portion P12.
[0076] exist Figure 4E In the example shown, the top portion P11 of the pin P1 is configured as a hollow cylindrical part, such as a cylinder, with an opening P113 at the top, and the locking portion P12 is configured as a cylinder. Furthermore, the top portion P11 has a plurality of slits P114 extending from the top along the protruding direction of the pin P1, configured to fit into the locking portion P2 in a state of elastic deformation toward the radially inward side of the pin P1. Figure 4E In the example shown, two slits P114 are provided at equal angular intervals at the top end P11 of the pin P1, but there can also be three, four, or more than five slits P114. In this example, Figure 2 The fitting portion P2 shown is also set as a bottomed cylindrical concave shape corresponding to the shape of the top portion P11, and the through hole 207h of the circuit board 207 is also formed as a cavity or hole shape corresponding to the shape of the locking portion P12.
[0077] Furthermore, in Figure 4C and Figure 4D In the example shown, the outer diameter OD1 of the top part P11 of the pin P1 can also be slightly larger than the inner diameter of the fitting part P2, so that a portion of the rib P111 is elastically or plastically deformed before fitting into the fitting part P2. Similarly, in Figure 4B and Figure 4DIn the example shown, the outer diameter OD2 of the locking portion P12 of the pin P1 can be slightly larger than the inner diameter of the through hole 207h of the circuit board 207, so that a part of the rib P121 undergoes elastic or plastic deformation, causing the locking portion P12 to engage with the locking surface 207f of the circuit board 207.
[0078] Figure 5 An example is shown illustrating the shape of the locking portion P12 of the pin P1 and the configuration of the through hole 207h on the circuit board 207. Figure 5 In the example shown, with Figure 3 As in the example shown, a pair of pins P1 are inserted into a pair of through holes 207h at one end and the other end of a pair of holes provided on the circuit board 207 along the surface direction Df. Here, the direction Dl of the circuit board 207 along the surface direction Df is, for example, like... Figure 3 The length direction of the measuring part 201m of the housing 201 is shown.
[0079] In addition, Figure 5 In the example shown, the pair of pins P1 have multiple ribs P121, including an outer rib P123 protruding outward along a direction Dl toward the circuit board 207, and an inner rib P124 protruding at an angle of 90 degrees or more relative to the protrusion direction of the outer rib P123. Furthermore, the dimension L3 from the tip of the outer rib P123 to the center of the pin P1 includes a positive dimensional tolerance of more than the radius of the through hole 207h. Furthermore, the dimension L4 from the tip of the inner rib P124 to the center of the pin P1 includes a negative dimensional tolerance of less than the radius of the through hole 207h.
[0080] More specifically, in Figure 3 and Figure 5 In the example shown, the locking portion P12 of the pin P1 has an outer rib P123. This outer rib P123 protrudes in a direction D1 parallel to the length direction of the measuring portion 201m of the housing 201, which is also the length direction of the circuit board 207. Furthermore, the locking portion P12 of the pin P1 has two inner ribs P124. These two inner ribs P124 protrude in directions having an angle of more than 90 degrees, for example, about 135 degrees, relative to the outer ribs P123 in the left rotation direction and the right rotation direction, respectively.
[0081] The function of the physical quantity detection device 20 in this embodiment will now be explained.
[0082] As described above, the physical quantity detection device 20 of this embodiment includes detection elements for detecting physical quantities, such as an intake air temperature sensor 203, a pressure sensor 204, a flow detection unit 205, and a humidity sensor 206, and a circuit board 207 on which these detection elements are mounted. Furthermore, the physical quantity detection device 20 includes a housing 201 that houses the circuit board 207 and a cover 202 fixed to the housing 201 and defining a flow path for the flow detection unit 205, which serves as the detection element. In this physical quantity detection device 20, the housing 201 and the cover 202 have a positioning portion P. This positioning portion P has a pin P1 extending along the thickness direction Dt of the circuit board 207 and a fitting portion P2 for engaging the top end P11 of the pin P1 to position the housing 201 and the cover 202. Furthermore, the pin P1 has a locking portion P12, which is opposite to the locking surface 207f of the circuit board 207 along the thickness direction Dt, thereby restricting the movement of the circuit board 207 along the surface direction Df of the surface and back surface.
[0083] With this configuration, the physical quantity detection device 20 of this embodiment improves the positioning accuracy of the housing 201 and the cover 202 compared to the conventional method, and reduces individual differences in the flow of fluid passing through the flow path where the detection element is arranged. Therefore, according to this embodiment, a physical quantity detection device 20 that can improve the measurement accuracy of physical quantities by the detection element compared to the conventional method can be provided.
[0084] More specifically, as a comparative embodiment not included in the disclosed embodiments, a physical quantity detection device is envisioned having a first pin and a first engaging portion for positioning the housing and the cover, and a second pin and a second engaging portion for positioning the housing and the circuit board. In this comparative embodiment of the physical quantity detection device, the first pin and the first engaging portion and the second pin and the second engaging portion are spaced apart in the surface direction of the circuit board.
[0085] Therefore, the positional relationship between the first pin and the first mating part and the second pin and the second mating part varies due to manufacturing tolerances, resulting in individual differences in the size and shape of the flow path of the measured gas defined by the housing and the cover for each physical quantity detection device. Consequently, individual differences arise in the flow of the measured gas, which is measured by the detection element arranged in the flow path, potentially affecting the accuracy of the physical quantity measurement.
[0086] In contrast, the physical quantity detection device 20 of this embodiment can position the housing 201 and the cover 202 by engaging the top end P11 of the pin P1 of the positioning part P with the engaging part P2. Furthermore, the locking part P12 of the pin P1 faces the locking surface 207f of the circuit board 207 in the surface direction Df. Therefore, even if a force is applied that moves the circuit board 207 in the surface direction Df, the locking part P12 of the pin P1 will abut against the locking surface 207f of the circuit board 207 and exert a reaction force, thereby preventing misalignment of the circuit board 207.
[0087] That is, the physical quantity detection device 20 of this embodiment can also position the housing 201 and the circuit board 207 by means of the pin P1 used for positioning the housing 201 and the cover 202. Therefore, the functions of the first pin and the second pin in the physical quantity detection device of the comparative form described above can be realized by one pin P1. As a result, the physical quantity detection device 20 of this embodiment can eliminate the problems caused by the tolerance between the first pin and the first fitting part and the second pin and the second fitting part in the physical quantity detection of the comparative form.
[0088] Therefore, according to this embodiment, a physical quantity detection device 20 can be provided that improves the positioning accuracy of the housing 201 and the cover 202 compared to the past, reduces the individual differences in the flow of fluid passing through the flow path for which the detection element is arranged, and improves the measurement accuracy of the physical quantity by the detection element compared to the past.
[0089] Furthermore, the physical quantity detection device 20 of this embodiment integrates the functions of the first and second pins of the physical quantity detection device in the comparative form into a single pin P1, thereby reducing the number of pins P1 required. As a result, the physical quantity detection device 20 can increase the space available for components other than the positioning portion P, including the circuit board 207 and the detection element, within the space defined by the housing 201 and the cover 202, thus improving the flexibility of its layout.
[0090] Furthermore, in the physical quantity detection device 20 of this embodiment, the outer diameter OD2 of the locking portion P12 of the pin P1 is larger than the outer diameter OD1 of the top portion P11.
[0091] With this configuration, for example, during the manufacture of the physical quantity detection device 20, when the circuit board 207 is housed in the housing 201 along the thickness direction Dt, i.e., the protruding direction of the pin P1, it is possible to suppress interference between the top end P11 of the pin P1 and the locking surface 207f of the circuit board 207. This improves the workability of the assembly operation where the circuit board 207 moves from the top end P11 to the locking part P12 in the protruding direction of the pin P1 and is housed in the housing 201, thereby improving the assemblability of the physical quantity detection device 20.
[0092] Furthermore, in the physical quantity detection device 20 of this embodiment, the pin P1 is provided in the housing 201, and the fitting part P2 is provided in the cover 202.
[0093] With this configuration, for example, during the manufacture of the physical quantity detection device 20, when the circuit board 207 is housed in the housing 201, the locking portion P12 of the pin P1 provided on the housing 201 can be aligned with the locking surface 207f of the circuit board 207 to position the housing 201 and the circuit board 207. Therefore, the detection element mounted on the circuit board 207 can be accurately positioned within the housing 201 at a predetermined location.
[0094] Subsequently, when fixing the cover 202 to the housing 201, the housing 201 and the cover 202 can be positioned by engaging the top end P11 of the pin P1 provided on the housing 201 with the engaging part P2 provided on the cover 202. Therefore, in the physical quantity detection device 20, individual differences in the shape and size of the secondary passage 234 defined by the housing 201 and the cover 202 can be reduced, and the measurement accuracy of the detection element including the flow detection unit 205 can be improved.
[0095] Furthermore, in the physical quantity detection device 20 of this embodiment, the fitting portion P2 is configured as a concave shape for fitting the top end portion P11 of the pin P1, and has an inner wall surface P21 that is opposite to the outer peripheral surface of the pin P1 in the surface direction Df of the circuit board 207 to restrict the movement of the pin P1.
[0096] With this configuration, for example, during the manufacture of the physical quantity detection device 20, the housing 201 and the cover 202 can be positioned in the planar direction Df of the circuit board 207 by engaging the pin P1 of the positioning portion P constituting the housing 201 and the cover 202 with the engagement portion P2. That is, when a force in the planar direction Df of the circuit board 207 acts between the housing 201 and the cover 202, the outer peripheral surface of the pin P1 constituting the positioning portion P abuts against the inner wall surface P21 of the concave engagement portion P2 and exerts a reaction force. As a result, misalignment of the housing 201 and the cover 202 in the planar direction Df of the circuit board 207 can be prevented, and the housing 201 and the cover 202 can be positioned in the planar direction Df of the circuit board 207.
[0097] Furthermore, in the physical quantity detection device 20 of this embodiment, the top end P11 of the pin P1 of the positioning part P and the locking part P12 can be, for example, like... Figure 4A It is formed into a cylindrical shape as shown.
[0098] With this configuration, for example, when the fitting portion P2 of the positioning portion P is a bottomed cylindrical recess and the locking surface 207f of the circuit board 207 is a cylindrical through hole 207h with openings at both ends in the surface direction Df, the management of the constraint effect of the positioning portion P on each component becomes easier. That is, the management of gaps or tightness between the top end P11 of the pin P1 and the inner wall surface P21 of the fitting portion P2, and between the locking portion P12 of the pin P1 and the locking surface 207f of the circuit board 207, becomes easier.
[0099] Furthermore, in the physical quantity detection device 20 of this embodiment, the locking portion P12 of the pin P1 of the positioning portion P is, for example, like... Figure 2 , Figure 3 as well as Figure 4B As shown, it has multiple ribs P121 that protrude radially toward the inner wall surface, i.e., the locking surface 207f, of the through hole 207h in the circuit board 207 along the pin P1.
[0100] With this configuration, the top ends of the multiple ribs P121 provided on the locking portion P12 of the pin P1 are aligned with the locking surface 207f of the circuit board 207, thereby constraining the movement of the circuit board 207 in the surface direction Df and positioning the circuit board 207. Furthermore, compared to the case where the locking portion P12 of the pin P1 is cylindrical, the contact area between the locking portion P12 and the locking surface 207f of the circuit board 207 can be reduced, and the stress acting on the locking portion P12 can be reduced. Therefore, even when the rigidity of the locking portion P12 of the pin P1 is low, the circuit board 207 can be constrained and positioned with reduced stress acting on the locking portion P12.
[0101] Furthermore, in the physical quantity detection device 20 of this embodiment, the top end P11 of the pin P1 of the positioning part P can, for example, be like... Figure 2 and Figure 4C As shown, it has multiple ribs P121 that protrude radially toward the inner wall surface P21 of the mating part P2.
[0102] This configuration allows the tops of multiple ribs P111 located at the top end P11 of the pin P1 to be aligned with the inner wall surface P21 of the fitting part P2, thereby constraining the relative movement of the housing 201 and the cover 202 for positioning. Furthermore, compared to a cylindrical top end P11 of the pin P1, this configuration reduces the contact area between the top end P11 and the inner wall surface P21 of the fitting part P2, thus reducing the stress acting on the top end P11. Therefore, even when the rigidity of the top end P11 of the pin P1 is low, the constraint and positioning of the housing 201 and the cover 202 can be achieved with reduced stress on the top end P11.
[0103] Furthermore, in the physical quantity detection device 20 of this embodiment, the top end P11 of the pin P1 of the positioning part P and the locking part P12 may, for example, be like... Figure 2 and Figure 4D As shown, it has multiple ribs P111 and multiple ribs P121 respectively. With this configuration, the physical quantity detection device 20 can obtain the aforementioned... Figure 4C The effect of pin P1 in the example shown is the same as described above. Figure 4D The combined effect of pin P1 in the example shown.
[0104] Furthermore, in the physical quantity detection device 20 of this embodiment, the top end P11 of the pin P1 is, for example, like... Figure 4E As shown, it is a hollow cylindrical shape with an opening P113 at the top, and has a plurality of slits P114 extending from the top along the protruding direction of the pin P1. The pin P1 is fitted into the fitting part P2 in a state of elastic deformation toward the radially upward inward.
[0105] With this configuration, the top part P11 of the pin P1 can be pressed against the inner wall surface P21 of the fitting part P2 by applying force to the outer peripheral surface of the top part P11 of the pin P1 in a radially outward direction. This eliminates the clearance between the outer peripheral surface of the top part P11 of the pin P1 and the inner wall surface P21 of the fitting part P2, more reliably constrains the housing 201 and the cover 202, and achieves higher positioning accuracy.
[0106] Furthermore, in the physical quantity detection device 20 of this embodiment, the locking surface 207f of the circuit board 207 is, for example, like... Figure 2 and Figure 3 As shown, it includes the inner wall surface of the through hole 207h provided on the circuit board 207.
[0107] With this configuration, the pin P1 of the positioning part P can be inserted into the through hole 207h of the circuit board 207, and the entire circumference of the outer peripheral surface of the locking part P12 of the pin P1 is aligned with the locking surface 207f of the circuit board 207, i.e., the inner wall surface of the through hole 207h. Therefore, the movement of the circuit board 207 in all directions along the surface direction Df can be restricted by using one pin P1 and one through hole 207h of the circuit board 207. Consequently, the number of pins P1 can be reduced, relatively increasing the space available for the circuit board 207 and detection elements, thereby enabling miniaturization of the physical quantity detection device 20 and increasing the degree of freedom in the layout of the circuit board 207 and detection elements.
[0108] Furthermore, the physical quantity detection device 20 of this embodiment, for example, is like... Figure 5As shown, a pair of pins P1 are inserted into a pair of through holes 207h at one end and the other end of a direction Dl along the surface direction Df on the circuit board 207. In this example, the locking portion P12 of the pair of pins P1 has multiple ribs P121, including an outer rib P123 protruding outward from the circuit board 207 along the aforementioned direction Dl, and an inner rib P124 protruding at an angle of 90 degrees or more relative to the protrusion direction of the outer rib P123. Furthermore, the dimension L3 from the top of the outer rib P123 to the center of the pin P1 includes a positive dimensional tolerance of more than the radius of the through hole 207h of the circuit board 207, and the dimension L4 from the top of the inner rib P124 to the center of the pin P1 includes a negative dimensional tolerance of less than the radius of the through hole 207h of the circuit board 207.
[0109] With this configuration, in one direction Dl along the surface direction Df of the circuit board 207, the outer ribs P123 of a pair of pins P1 exert opposing forces on the inner wall surfaces (i.e., locking surfaces 207f) of a pair of through holes 207h of the circuit board 207, directed outwards. More specifically, for example, at the locking portion P12 of the pins P1, the tip of the outer rib P123 abuts against the inner wall surface of the through hole 207h of the circuit board 207 in a state of elastic or plastic deformation, exerting a force on that inner wall surface in the surface direction Df outwards. Thus, the circuit board 207 can be constrained and positioned by the locking portion P12 of the pins P1 while a tensile force acts between the pair of through holes 207h of the circuit board 207. Therefore, the circuit board 207 can be positioned with higher precision by preventing it from shifting in one direction Dl along the surface direction Df.
[0110] Furthermore, in the physical quantity detection device 20 of this embodiment, the number of pins P1 is, for example, 1 or more and 3 or less.
[0111] With this configuration, the physical quantity detection device 20 of this embodiment can accurately position the housing 201 and the cover 202, as well as the housing 201 and the circuit board 207, without increasing the space required for the pin P1. In particular, if the number of pins P1 is only one, the space required for the circuit board 207 and the detection element can be further increased, and the miniaturization of the physical quantity detection device 20 and the layout freedom of the circuit board 207 and the detection element can be improved more reliably.
[0112] Furthermore, if there are two pins P1, the relative rotation between the housing 201 and the cover 202, and the relative rotation between the housing 201 and the circuit board 207, centered on a rotation axis parallel to the protruding direction of the pins P1, can be suppressed. Therefore, the positioning of the housing 201 and the cover 202, as well as the positioning of the housing 201 and the circuit board 207, can be performed with higher precision.
[0113] Furthermore, if there are three pins P1, not only can the aforementioned rotation be suppressed, but the constraint force between the housing 201 and the cover 202, as well as the constraint force between the housing 201 and the circuit board 207, can also be increased in the protruding direction of the pins P1. This, for example, can prevent misalignment in the thickness direction of the circuit board 207 caused by the effect of the adhesive used to bond the circuit board 207 to the housing 201.
[0114] As explained above, according to this embodiment, a physical quantity detection device 20 can be provided that improves the positioning accuracy of the housing 201 and the cover 202 compared to the past, reduces the individual differences in the flow of fluid passing through the flow path for which the detection element is arranged, and improves the measurement accuracy of the physical quantity by the detection element compared to the past.
[0115] [Implementation Method 2]
[0116] Next, quote Figure 1 and Figures 3 to 5 And refer to Figure 6 Embodiment 2 of the physical quantity detection device disclosed herein will be described. Figure 6 This is equivalent to Implementation Method 1 described above. Figure 2 A schematic cross-sectional view of the physical quantity detection device 20A of this embodiment.
[0117] In the physical quantity detection device 20A of this embodiment, the configuration of the positioning part P is different from that of the physical quantity detection device 20 of Embodiment 1 described above. The other configurations of the physical quantity detection device 20A of this embodiment are the same as those of the physical quantity detection device 20 of Embodiment 1 described above; therefore, the same symbols are used to mark the same parts and descriptions are omitted.
[0118] like Figure 6 As shown, in the physical quantity detection device 20A of this embodiment, the pin P1 has a first part P1a and a second part P1b. The first part P1a is disposed in the housing 201 and includes a locking part P12. The second part P1b is disposed in the cover 202 and includes a top part P11. The fitting part P2 is disposed at the top of the first part P1a of the pin P1, and its diameter is expanded by fitting the top part P11 of the second part P1b of the pin P1, thereby restricting the movement of the circuit board 207 in the thickness direction Dt.
[0119] With this configuration, the physical quantity detection device 20A of this embodiment not only achieves the same effect as the physical quantity detection device 20 of Embodiment 1 described above, but also more reliably positions the circuit board 207 in the thickness direction Dt. More specifically, during the manufacture of the physical quantity detection device 20, as... Figure 6 As shown, the circuit board 207 is first housed in the housing 201.
[0120] Next, the first part P1a of the pin P1 provided on the housing 201 is inserted into the through hole 207h of the circuit board 207, so that the locking part P12 of the first part P1a is opposite to the locking surface 207f of the circuit board 207. In this state, the cover 202 is fixed to the housing 201, so that the top end P11 of the second part P1b of the pin P1 provided on the cover 202 is fitted into the fitting part P2 of the top end of the first part P1a of the pin P1 provided on the housing 201.
[0121] Therefore, the fitting portion P2 at the top of the first part P1a of pin P1 is expanded from the inside to the outside by the top portion P11 of the second part P1b of pin P1, thus increasing its diameter. Here, as... Figure 6 As shown, the outer diameter of the top part P11 of the pin P1 is larger than the inner diameter of the fitting part P2. Furthermore, from the viewpoint of making fitting easier, it is preferable to set the top part P11 of the second part P1b of the pin P1 to be conical, and to make the outer diameter of the top of the second part P1b smaller than the inner diameter of the fitting part P2 of the top of the first part P1a.
[0122] Thus, after the first part P1a of the pin P1 is inserted into the through hole 207h of the circuit board 207, the fitting portion P2 at the top of the first part P1a is enlarged. This allows the fitting portion P2 to function as a "flipping portion" to prevent the first part P1a from detaching from the circuit board 207. This, for example, can prevent misalignment in the thickness direction of the circuit board 207 caused by the hardening of the adhesive used to bond the circuit board 207 to the housing 201, and improves the positioning accuracy of the thickness direction Dt of the circuit board 207.
[0123] The embodiments of the physical quantity detection device disclosed herein have been described in detail above with the aid of the accompanying drawings. However, the specific configuration is not limited to this embodiment. Even if there are design changes that do not depart from the spirit of this disclosure, they are also included in this disclosure.
[0124] Symbol Explanation
[0125] 20…Physical quantity detection device
[0126] 201…shell
[0127] 202… Cover
[0128] 203…Intake air temperature sensor (detection element)
[0129] 204… Pressure sensor (sensing element)
[0130] 205… Flow detection section (detection element)
[0131] 206…Humidity sensor (detection element)
[0132] 207…Circuit Board
[0133] 207f…card stop surface
[0134] 207h…through hole
[0135] 234...Sub-passage (flow path)
[0136] Df…face direction
[0137] Dl… one direction
[0138] Dt…thickness direction
[0139] L3…size
[0140] L4…size
[0141] OD2…Outer diameter of the locking part
[0142] OD1…Outer diameter of the tip
[0143] P… Positioning Department
[0144] P1…Pin lever
[0145] P11…Top section
[0146] P111…ribs
[0147] P113…Opening
[0148] P114… Slit
[0149] P12… Locking part
[0150] P121…ribs
[0151] P123…outer ribs
[0152] P124…Inner Rib
[0153] P1a…Part 1
[0154] P1b…Part 2
[0155] P2…fitting part
[0156] P21…Inner wall surface.
Claims
1. A physical quantity detection device comprising: a detection element for detecting a physical quantity; a circuit board on which the detection element is mounted; a housing for housing the circuit board; and a cover fixed to the housing for defining a flow path for arranging the detection element, characterized in that... The housing and the cover have positioning parts. The positioning part has a pin extending along the thickness direction of the circuit board and a fitting part for the top end of the pin to fit into the housing and the cover for positioning. The pin has a locking portion that faces a locking surface of the circuit board along the thickness direction, thereby restricting movement of the circuit board along the surface direction of its surface and back surface. The pin has a first part and a second part, the first part being disposed in the housing and including the locking portion, and the second part being disposed in the cover and including the top end portion. The fitting portion is disposed at the top end of the first part of the pin, and its diameter is expanded by fitting the top end of the second part of the pin, thereby restricting the movement of the circuit board in the thickness direction.
2. The physical quantity detection device according to claim 1, characterized in that, The outer diameter of the locking portion of the pin is larger than the outer diameter of the top portion.
3. The physical quantity detection device according to claim 1, characterized in that, The pin is disposed on the housing. The fitting portion is disposed on the cover.
4. The physical quantity detection device according to claim 1, characterized in that, The fitting portion is configured as a concave shape for fitting the top end of the pin, and has an inner wall surface that is opposite to the outer peripheral surface of the pin in the surface direction of the circuit board to restrict the movement of the pin.
5. The physical quantity detection device according to claim 4, characterized in that, The top end of the pin has a plurality of ribs that protrude radially toward the inner wall surface of the fitting portion.
6. The physical quantity detection device according to claim 4, characterized in that, The top end of the pin is configured as a hollow cylinder with an opening at the top end, and has a plurality of slits extending from the top end along the protruding direction of the pin, so as to fit into the fitting portion in a state of elastic deformation toward the radially inner side of the pin.
7. The physical quantity detection device according to claim 1, characterized in that, The locking surface includes the inner wall surface of the through hole provided on the circuit board.
8. The physical quantity detection device according to claim 7, characterized in that, The locking portion of the pin has a plurality of ribs that protrude radially toward the inner wall surface of the through hole.
9. The physical quantity detection device according to claim 8, characterized in that, A pair of pins are inserted into a pair of through holes at one end and the other end of a circuit board along the surface direction. The pair of pins includes a plurality of ribs comprising an outer rib projecting outward toward the outside of the circuit board along said direction and an inner rib projecting at an angle of more than 90 degrees relative to the projection direction of the outer rib. The dimension from the top of the outer rib to the center of the pin includes a positive dimensional tolerance above the radius of the through hole. The dimension from the top of the inner rib to the center of the pin includes a negative dimensional tolerance below the radius of the through hole.
10. The physical quantity detection device according to claim 1, characterized in that, The number of pins is more than 1 and less than 3.