Physical quantity measuring device

Abstract

The physical quantity measuring device of the present application suppresses thermal stress generated near the interface of the housing and the sealing member, thereby easily ensuring the connection reliability of the lead wire. A physical quantity measuring device (20) includes a housing (100); a connector terminal (117) sealed in the housing (100); a lead wire (350) joined to the connector terminal (117); and a sealing member (250) that seals the lead wire (350) and is in contact with the connector terminal (117) and the housing (100). The linear expansion coefficient of the housing (100) is greater than that of the sealing member (250). The connector terminal (117) has a joint surface (118) and a side surface (119) continuous with the joint surface (118) and sealed in the housing (100). The housing (100) has a first surface (115) in contact with the side surface (119) and a second surface (116) continuous with the first surface (115) and in contact with the sealing member (250). An end portion (116a) of the second surface (116) continuous with the first surface (115) is formed in a flush shape with the joint surface (118).

Description

Technical Field

[0001] This invention relates to a device for measuring physical quantities. Background Technology

[0002] Physical quantities such as airflow, pressure, temperature, and humidity are widely used as important control parameters in various devices. Devices that measure these physical quantities are crucial components influencing device performance. For example, vehicles equipped with internal combustion engines have very high requirements for fuel efficiency and exhaust purification. To meet these requirements, a high-precision device is needed to measure the intake air volume, a key control parameter of the internal combustion engine.

[0003] Such a physical quantity measuring device is disclosed, for example, in Patent Document 1. The device in Patent Document 1 has a structure in which a circuit board is bonded to a housing, and a sensor for measuring the amount of intake air is mounted on the circuit board. The circuit board, on which electronic components such as the sensor are mounted, and the connector terminals for providing electrical signals from the circuit board to an external device are sometimes connected by wire bonding. For example, Patent Document 2 discloses a method for connecting the circuit board and the connector terminals by wire bonding. In the device of Patent Document 2, the connector terminals, integrally formed with the housing, and the circuit board housed within the housing are connected by wire bonding.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2015 / 117971

[0007] Patent Document 2: Japanese Patent Application Publication No. 2004-28934 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In physical quantity measuring devices, connector terminals integrally formed with the housing and circuit boards housed within the housing are sometimes connected by wire bonding, and then sealed with a resin sealing member. In this case, if the linear expansion coefficient of the housing is greater than that of the sealing member, significant thermal stress will be generated near the interface between the housing and the sealing member. Consequently, the connector terminals sealed within the housing and the sealing member may peel off, and the leads sealed within the sealing member may break due to thermal fatigue. It is possible to select a resin material for the housing such that the difference in linear expansion coefficients between the housing and the sealing member is very small. However, resin materials that achieve a small difference in linear expansion coefficients while meeting the performance requirements of physical quantity measuring devices operating in harsh environments are expensive, making it difficult to use such a resin material for the housing.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a physical quantity measuring device that can suppress thermal stress generated near the interface between the housing and the sealing member, thereby easily ensuring the reliability of the lead connection.

[0011] Technical means for solving technical problems

[0012] To address the aforementioned problems, the physical quantity measuring device of the present invention includes: a housing that accommodates a sensor for measuring a physical quantity; a terminal sealed within the housing; a lead wire engaging with the terminal; and a sealing member that seals the lead wire and contacts both the terminal and the housing, wherein the linear expansion coefficient of the housing is greater than that of the sealing member, the terminal having a mating surface that engages the lead wire and contacts the sealing member; and a side surface continuous with the mating surface and sealed within the housing, the housing having a first surface that contacts the side surface of the terminal; and a second surface continuous with the first surface and in contact with the sealing member, the end of the second surface continuous with the first surface being formed flush with the mating surface.

[0013] Invention Effects

[0014] According to the present invention, a physical quantity measuring device can be provided that can suppress thermal stress generated near the interface between the housing and the sealing member, thereby easily ensuring the reliability of the lead connection. Other problems, structures, and effects beyond those described above become clearer through the following description of embodiments. Attached Figure Description

[0015] Figure 1 This is a diagram showing the structure of an internal combustion engine control system using an electronic fuel injection method employing the physical quantity measurement device of this embodiment.

[0016] Figure 2 This is a front view of the physical quantity measuring device of this embodiment.

[0017] Figure 3 yes Figure 2 The rear view of the physical quantity measuring device shown.

[0018] Figure 4 It was removed Figure 2 The front view of the physical quantity measuring device behind the cover shown.

[0019] Figure 5 It was removed Figure 3 Rear view of the physical quantity measuring device behind the sealing component shown.

[0020] Figure 6 yes Figure 5An enlarged view of the area near the connector terminals shown.

[0021] Figure 7 yes Figure 6 The diagram shows a cross-section of line AA.

[0022] Figure 8 yes Figure 7 An enlarged view of the area enclosed by the dotted line.

[0023] Figure 9 This is a diagram used to illustrate the physical quantity measuring device for the comparative example.

[0024] Figure 10 yes Figure 9 An enlarged view of the area enclosed by the dotted line.

[0025] Figure 11 This is a diagram illustrating a physical quantity measuring device in a modified embodiment of this invention.

[0026] Figure 12 yes Figure 11 An enlarged view of the area enclosed by the dotted line. Detailed Implementation

[0027] The embodiments of the present invention will now be described using the accompanying drawings. Furthermore, unless otherwise specified, structures labeled with the same reference numerals in each embodiment have the same function in each embodiment, and therefore their description is omitted.

[0028] Figure 1 This is a diagram showing the structure of an internal combustion engine control system 1 using the electronic fuel injection method of the physical quantity measuring device 20 of this embodiment.

[0029] In the internal combustion engine control system 1, based on the operation of the internal combustion engine 10, which includes engine cylinders 11 and engine pistons 12, the measured gas 2, which is intake air, is drawn in from the air purifier 21 and guided to the combustion chamber of the engine cylinder 11 via, for example, the intake air passage 22, the throttle body 23, and the intake manifold 24. The physical quantity of the measured gas 2, which is intake air guided to the combustion chamber, is measured by the physical quantity measuring device 20 of this embodiment. Based on the measured physical quantity, fuel is supplied from the fuel injection valve 14 and guided to the combustion chamber in a mixed state with the measured gas 2. In this embodiment, the fuel injection valve 14 is provided at the intake port of the internal combustion engine. The fuel injected into the intake port forms a mixed gas with the measured gas 2 and is guided to the combustion chamber via the intake valve 15, where it burns to generate mechanical energy.

[0030] Fuel and air, guided into the combustion chamber, form a fuel-air mixture, which is ignited and combusted by the spark plug 13 to generate mechanical energy. 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 measured gas 2, which is the intake air guided into the combustion chamber, is controlled by a throttle valve 25, the opening of which changes based on the action of the accelerator pedal. By controlling the flow rate of the intake air guided into the combustion chamber, the driver can control the mechanical energy generated by the internal combustion engine by controlling the flow rate of the intake air guided into the combustion chamber through the throttle valve 25.

[0031] The physical quantity measuring device 20 measures physical quantities such as flow rate, temperature, humidity, or pressure of the intake air (gas 2 being measured) drawn in from the air purifier 21 and flowing through the main passage 22, and an electrical signal representing the physical quantity of the intake air is input from the physical quantity measuring device 20 to the control device 4. Furthermore, the output of the throttle valve angle sensor 26, used to measure the opening of the throttle valve 25, is input to the control device 4, and the output of the rotation angle sensor 17, used 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 rotational speed of the internal combustion engine 10, is input to the control device 4. The output of the oxygen sensor 28, used to measure the mixture ratio between the fuel and air quantities based on the state of the exhaust gas 3, is input to the control device 4.

[0032] The control device 4 calculates the fuel injection quantity and ignition timing based on the physical quantity of the intake air output by the physical quantity measuring device 20 and the rotational speed of the internal combustion engine 10 measured based on the output of the rotation angle sensor 17. Based on the above calculation results, it controls the amount of fuel supplied from the fuel injection valve 14 and the ignition timing ignited by the spark plug 13. In fact, it further finely controls the fuel supply quantity and ignition timing based on the temperature measured by the physical quantity measuring device 20, the change in throttle valve angle, the change in engine speed, and the air-fuel ratio measured by the oxygen sensor 28. The control device 4 also controls the amount of air bypassing the throttle valve 25 through the idle air control valve 27 and controls the speed of the internal combustion engine 10 in the idle state when the internal combustion engine is idling.

[0033] The fuel supply and ignition timing, which are the main control quantities of the internal combustion engine 10, are calculated using the output of the physical quantity measuring device 20 as the main parameters. Therefore, improving the measurement accuracy of the physical quantity measuring device 20, suppressing changes over time, and improving its reliability are crucial for improving the control accuracy and ensuring the reliability of the vehicle.

[0034] In recent years, in particular, expectations for vehicle fuel efficiency and exhaust gas purification have been very high. To meet these requirements, it is crucial to accurately measure the physical quantities of the intake air using the physical quantity measuring device 20. Furthermore, maintaining high reliability of the physical quantity measuring device 20 is also very important.

[0035] Furthermore, vehicles equipped with the physical quantity measuring device 20 are used in environments with significant temperature or humidity variations. Therefore, it is also desirable to consider the physical quantity measuring device 20's response to changes in temperature and humidity in its operating environment, as well as its response to dust and contaminants.

[0036] Furthermore, the physical quantity measuring device 20 is installed on the intake manifold, which is affected by the heat generated by the internal combustion engine 10. Therefore, the heat generated by the internal combustion engine is transferred to the physical quantity measuring device 20 via the intake manifold. The physical quantity measuring device 20 measures the flow rate of the gas being measured 2 by heat transfer with the gas being measured 2, so it is important to suppress the influence of external heat as much as possible.

[0037] As described below, the physical quantity measuring device 20 mounted on a vehicle not only solves the problems listed in the "Problems to be Solved by the Invention" section and achieves the effects listed in the "Effects of the Invention" section, but also fully considers the aforementioned problems, solves various problems required as a product, and achieves various effects. The specific problems to be solved and the specific effects of the physical quantity measuring device 20 will be described in the following description.

[0038] Figure 2 This is a front view of the physical quantity measuring device 20 of this embodiment. Figure 2 This shows the state in which the cover 200 is installed onto the housing 100. Figure 3 yes Figure 2 The rear view of the physical quantity measuring device 20 shown. Figure 3 This shows the state in which the sealing member 250 covers the circuit board 300. Figure 4 It is to remove Figure 2 The front view of the physical quantity measuring device 20 behind the cover 200 shown. Figure 5 It is to remove Figure 3 The rear view of the physical quantity measuring device 20 behind the sealing member 250 is shown. In the following description, the measured gas 2 flows along... Figure 1 The flow occurs along the central axis 22a of the main passage 22 shown.

[0039] The physical quantity measuring device 20 is used when it is inserted into the main passage 22 through a mounting hole provided on the passage wall of the main passage 22 and fixed to the main passage 22. The physical quantity measuring device 20 includes a housing disposed in the main passage 22 through which the gas to be measured 2 flows. The housing of the physical quantity measuring device 20 has an outer shell 100, a cover 200 mounted on the front part 121 of the measuring part 113 (described later) of the outer shell 100, and a sealing member 250 sealing the circuit board 300 exposed from the back part 122 of the measuring part 113.

[0040] The outer casing 100 is formed, for example, by injection molding of a synthetic resin material. Examples of resin materials used in molding the outer casing 100 include relatively inexpensive PBT (polybutylene terephthalate) resin, which meets the performance requirements of the physical quantity measuring device 20. The cover 200 is formed by a plate-shaped member, for example, made of a metal material or a synthetic resin material. In this embodiment, it is formed by injection molding of an aluminum alloy or a synthetic resin material. The cover 200 has a size that completely covers the front portion 121 of the measuring portion 113. The sealing member 250 is formed, for example, by flowing synthetic resin material into the exposed area of ​​the circuit board 300 at the back portion 122 of the measuring portion 113 and molding it. Examples of resin materials used in molding the sealing member 250 include epoxy resin, which meets the performance requirements of the physical quantity measuring device 20.

[0041] The housing 100 has a flange 111 for securing the physical quantity measuring device 20 to the main passage 22, and a connector 112 that protrudes from the flange 111 and protrudes from the main passage 22 to the outside for electrical connection to an external device. Furthermore, the housing 100 has a measuring section 113 that extends from the flange 111 toward the central axis 22a of the main passage 22 for measuring the physical quantity of the gas 2 being measured flowing through the main passage 22.

[0042] The measuring section 113 is the part of the housing 100 that houses sensors for measuring physical quantities such as flow rate, temperature, humidity, or pressure. Specifically, the measuring section 113 houses a chip package 310 with a flow detection element 321, a temperature sensor 331, a humidity sensor 333, and a pressure sensor 335. The measuring section 113 has a thin and elongated shape that extends straight from the flange 111. The measuring section 113 has a wide front section 121 and a back section 122, a pair of narrow side sections 123 and 124, and a narrow front section 125.

[0043] The front portion 121 and the back portion 122 are rectangular surfaces with the long side and short side of the measuring portion 113 respectively as the long side and the short side, and are the main surfaces with the larger area among the surfaces constituting the measuring portion 113. The front portion 121 is the part of the measuring portion 113 that forms the secondary passages 134 and 135. The back portion 122 is the part of the measuring portion 113 opposite to the front portion 121. When the physical quantity measuring device 20 is mounted on the main passage 22, the front portion 121 and the back portion 122 are arranged parallel to each other along the central axis 22a of the main passage 22. The side portion 123 is located on one side of the measuring portion 113 in the short side direction, and when the physical quantity measuring device 20 is mounted on the main passage 22, the side portion 123 is arranged facing the upstream side of the main passage 22. Side portion 124 is located on the opposite side of the measuring portion 113 in the short side direction, and side portion 123 is arranged facing the downstream side of the main passage 22 when the physical quantity measuring device 20 is mounted on the main passage 22. Front end portion 125 is a surface continuous with front portion 121, back portion 122, side portion 123, and side portion 124. Front end portion 125 is located on the end face of the measuring portion 113 away from the flange 111, and is arranged parallel to the central axis 22a of the main passage 22 when the physical quantity measuring device 20 is mounted on the main passage 22. In the physical quantity measuring device 20, by making the side portions 123 and 124 facing the upstream and downstream sides of the main passage 22 have a narrower shape, the fluid resistance experienced by the measured gas 2 can be suppressed to a smaller value.

[0044] In this embodiment, the physical quantity measuring device 20, when mounted on the main passage 22, is positioned such that the base end of the measuring portion 113 near the flange 111 is positioned on the upper side, and the front end portion 125 of the measuring portion 113, which is away from the flange 111, is positioned on the lower side. However, the posture of the physical quantity measuring device 20 when mounted on the main passage 22 is not limited to this embodiment, and it can have various postures. For example, the physical quantity measuring device 20 can be mounted horizontally, such that the base end of the measuring portion 113 and the front end portion 125 are at the same height.

[0045] In the measuring unit 113, the inlets 131 of the secondary passages 134 and 135 are provided on the side portion 123, and the first outlet 132 and the second outlet 133 are provided on the side portion 124. The inlet 131, the first outlet 132, and the second outlet 133 are located near the front end portion 125 of the measuring unit 113 in the direction from the flange 111 toward the central axis 22a of the main passage 22. The second outlet 133 is positioned downstream of the main passage 22. The second outlet 133 has an opening area slightly larger than the first outlet 132 and is located closer to the base end of the measuring unit 113 than the first outlet 132. The measuring unit 113 can draw the portion of the gas to be measured 2 flowing through the inner surface of the main passage 22 away from the passage wall and near the central axis 22a into the secondary passages 134 and 135. Therefore, the physical quantity measuring device 20 can measure the flow rate of the gas to be measured 2 flowing through the portion near the central axis 22a, and can suppress the decrease in measurement accuracy caused by the influence of heat, etc.

[0046] The measuring unit 113 is provided with: secondary passages 134 and 135, which are used to draw in a portion of the gas 2 to be measured flowing through the main passage 22; and a circuit board 300, on which a sensor for measuring physical quantities is mounted.

[0047] Sub-passages 134 and 135 are recessed on the front face portion 121 of the measuring section 113 and are covered by a cover portion 200 mounted on the housing 100. A circuit board 300 is disposed in the measuring section 113 near the side face portion 123. Sub-passages 134 and 135 are disposed across a region in the measuring section 113 closer to the front face portion 125 than the circuit board 300 and a region closer to the side face portion 124 than the circuit board 300. Sub-passages 134 and 135 have a first sub-passage 134 and a second sub-passage 135.

[0048] A first secondary passage 134 is formed by spanning the inlet 131, which opens on the side portion 123 of the measuring section 113, and the first outlet 132, which opens on the side portion 124 of the measuring section 113, extending along the short side direction of the measuring section 113. The first secondary passage 134 is a flow path that extends from the inlet 131 and connects to the first outlet 132 along the flow direction of the measured gas 2 in the main passage 22. The first secondary passage 134 draws in the measured gas 2 flowing through the main passage 22 from the inlet 131 and returns the drawn-in measured gas 2 from the first outlet 132 back to the main passage 22.

[0049] The second auxiliary passage 135 has a destination portion 136 that branches off midway from the first auxiliary passage 134 and extends toward the base end of the measuring section 113 (towards the flange 111), and a return portion 137 that bends back and makes a U-turn at the base end of the measuring section 113 and extends toward the front end face 125 of the measuring section 113. The destination portion 136 branches off midway from the first auxiliary passage 134 and extends away from the first auxiliary passage 134. The return portion 137 bends back and makes a U-turn at the end of the destination portion 136 and extends toward the first auxiliary passage 134. The return portion 137 connects to a second outlet 133 that opens toward the downstream side of the main passage 22 at a position closer to the inlet 131 than the downstream side of the main passage 22. The second auxiliary passage 135 allows the measured gas 2 that branches off from the first auxiliary passage 134 and flows in to return to the main passage 22 from the second outlet 133. Since the second auxiliary passage 135 has a destination section 136 and a return section 137 extending along the long side of the measuring section 113, a longer passage length can be ensured. Therefore, even if pulsation occurs in the main passage 22, the flow detection element 321 arranged in the second auxiliary passage 135 can measure the flow rate of the gas 2 being measured through the second auxiliary passage 135, and is not greatly affected by the pulsation.

[0050] The circuit board 300 is generally rectangular in top view. The circuit board 300 is disposed in the measuring section 113 such that the long side of the circuit board 300 extends from the base end of the measuring section 113 toward the front end portion 125, and the short side of the circuit board 300 extends from the side portion 123 of the measuring section 113 toward the side portion 124.

[0051] The circuit board 300 is a circuit board capable of mounting electronic components on both mounting surfaces 300a and 300b. Mounting surface 300a of the circuit board 300 is disposed on the front surface 121 of the measuring section 113. Mounting surface 300b of the circuit board 300 is disposed on the back surface 122 of the measuring section 113. Electronic components such as the chip package 310 supporting the flow detection element 321, the temperature sensor 331, the humidity sensor 333, and the pressure sensor 335 are mounted on mounting surface 300a of the circuit board 300. Electronic components such as the LSI 341 and the microcomputer 343 are mounted on mounting surface 300b of the circuit board 300.

[0052] A chip package 310 is mounted on the central portion of the mounting surface 300a of the circuit board 300. The chip package 310 has a fixing portion 311 fixed to the central portion of the mounting surface 300a and an extension portion 312 extending from the fixing portion 311 toward the outlet portion 136 of the second secondary passage 135. A flow detection element 321 is disposed in the extension portion 312. The flow detection element 321 has a diaphragm-like (thin film-like) detection surface, which is exposed in the outlet portion 136 of the second secondary passage 135. The flow detection element 321 measures the flow rate of the gas 2 being measured and drawn into the outlet portion 136 of the second secondary passage 135.

[0053] Temperature sensor 331 is mounted on the end of the circuit board 300 near inlet 131 on the mounting surface 300a. Temperature sensor 331 is positioned midway through the temperature detection passage of measuring section 113, which has one end open near inlet 131 and the other end open on both the front and back portions 121 and 122. Temperature sensor 331 measures the temperature of the gas 2 being drawn into the temperature detection passage.

[0054] The humidity sensor 333 is mounted on the mounting surface 300a of the circuit board 300 and is closer to the front face 125 of the measuring section 113 than the chip package 310. The humidity sensor 333 measures the humidity of the gas 2 being measured, which is drawn in through the window of the measuring section 113 that opens to the back face 122.

[0055] The pressure sensor 335 is mounted on the mounting surface 300a of the circuit board 300 and is closer to the base end of the measuring section 113 than the chip package 310. The pressure sensor 335 measures the pressure of the gas to be measured 2 drawn into the pressure inlet passage of the measuring section 113, which opens midway through the second secondary passage 135.

[0056] The LSI341 and microcomputer 343 are mounted on the mounting surface 300b of the circuit board 300. The LSI341 and microcomputer 343 perform various signal processing and arithmetic operations on the output signals from the flow sensing element 321, temperature sensor 331, humidity sensor 333, or pressure sensor 335, and output an electrical signal, i.e., a measurement signal, representing the measurement result of the physical quantity. This measurement signal is output from connector 112 to the outside of the physical quantity measuring device 20 via the wiring pattern, electrode pads 301, leads 350, and connector terminals 117 of the circuit board 300. The measurement signal output to the outside of the physical quantity measuring device 20 is input to the control device 4.

[0057] Figure 6 yes Figure 5 An enlarged view of the area near connector terminal 117 shown. Figure 7 yes Figure 6 The diagram shows a cross-section of line AA. Figure 8 yes Figure 7 An enlarged view of the area enclosed by the dotted line.

[0058] Connector terminal 117 is a terminal that outputs a measurement signal of a physical quantity to the outside. Connector terminal 117 is integrally formed with housing 100 by means of insertion molding or the like. Connector terminal 117 is sealed within terminal sealing portion 114 while a portion of it protrudes from terminal sealing portion 114 of housing 100. Connector terminal 117 is formed of a plate-shaped member made of, for example, a conductive material such as phosphor bronze. The linear expansion coefficient of connector terminal 117 can be 10 ppm / K or more and 30 ppm / K or less, for example, it can be around 20 ppm / K.

[0059] like Figure 8 As shown, connector terminal 117 has a mating surface 118 and a side surface 119. The mating surface 118 is the surface that protrudes from the terminal seal portion 114 of the housing 100 and is mated with the lead 350. The mating surface 118 contacts the sealing member 250. The mating surface 118 extends in the width direction and axial direction of connector terminal 117. The side surface 119 is a surface continuous with the mating surface 118 and is sealed within the terminal seal portion 114 of the housing 100. The side surface 119 extends in the thickness direction and axial direction of connector terminal 117.

[0060] The width direction of connector terminal 117 is orthogonal to side surface 119 and is the short side direction of measuring section 113. In this embodiment, the width direction of connector terminal 117 is defined as the X-axis, and the direction from side surface 123 to side surface 124 in the short side direction of measuring section 113 is defined as the +X-axis direction. The thickness direction of connector terminal 117 is orthogonal to mating surface 118 and is orthogonal to both the long and short side directions of measuring section 113. In this embodiment, the thickness direction of connector terminal 117 is defined as the Y-axis, and the direction from front surface 121 to back surface 122 in the direction orthogonal to both the long and short side directions of measuring section 113 is defined as the +Y-axis direction. The axial direction of connector terminal 117 is orthogonal to both the width and thickness directions of connector terminal 117 and is the long side direction of measuring section 113. In this embodiment, the axial direction of the connector terminal 117 is set as the Z-axis, and the direction from the base end of the measuring part 113 toward the front end face 125 in the long side direction of the measuring part 113 is set as the +Z-axis direction.

[0061] like Figure 6 and Figure 7As shown, the connector terminal 117 may be composed of a plurality of connector terminals 117 arranged at intervals in the width direction of the connector terminal 117. The plurality of connector terminals 117 includes a connector terminal 117a that is closest to the side portion 123 in the width direction; and a connector terminal 117b that is closest to the side portion 124 in the width direction.

[0062] Lead 350 is a bonding wire used to connect the circuit board 300 and the connector terminal 117 via lead bonding. For example... Figure 6 As shown, lead 350 connects the electrode pad 301 of the mounting surface 300b of the circuit board 300 to the mating surface 118 of the connector terminal 117. Lead 350 is formed of a wire-like component made of a metal material such as aluminum or copper. The linear expansion coefficient of lead 350 can be above 10ppm / K and below 30ppm / K, for example, it can be around 20ppm / K.

[0063] The sealing member 250 covers the mounting surface 300b of the circuit board 300 exposed from the back side 122 of the measuring section 113 of the housing 100. The sealing member 250 is formed, for example, by molding a synthetic resin material such as epoxy resin. The linear expansion coefficient of the sealing member 250 can be 10 ppm / K or more and 30 ppm / K or less below the glass transition temperature; for example, it can be around 20 ppm / K. Figure 8 As shown, the sealing member 250 seals the lead 350. The sealing member 250 contacts the mating surface 118 of the connector terminal 117 and the terminal sealing portion 114 of the housing 100.

[0064] The terminal sealing portion 114 of the housing 100 is used to seal the connector terminal 117 located at the base end of the measuring portion 113. The housing 100, including the terminal sealing portion 114, is formed by molding a synthetic resin material such as PBT (polybutylene terephthalate) resin. The housing 100 is formed using a resin material having a larger coefficient of linear expansion than the sealing member 250. The coefficient of linear expansion of the housing 100 can be 60 ppm / K or more and 110 ppm / K or less below the glass transition temperature, for example, it can be around 100 ppm / K. The coefficient of linear expansion of the housing 100 can be five times or more and six times or less than the coefficient of linear expansion of the sealing member 250.

[0065] like Figure 8As shown, the terminal sealing portion 114 has a first surface 115 and a second surface 116. The first surface 115 is the surface that contacts the side surface 119 of the connector terminal 117. The first surface 115 extends in the thickness direction and axial direction of the connector terminal 117. The second surface 116 is the surface that is continuous with the first surface 115 and is the surface that contacts the sealing member 250. The second surface 116 extends in the width direction and axial direction of the connector terminal 117.

[0066] The second surface 116 is the end of the connector terminal 117 in the width direction of the second surface 116, and has an end 116a that is continuous with the first surface 115. The height of the end 116a of the second surface 116 (the position of the connector terminal 117 in the thickness direction) is the same as the height of the mating surface 118. That is, the end 116a of the second surface 116 is formed to be flush with the mating surface 118. In other words, the end 116a of the second surface 116 is formed to be disposed on the same plane as the mating surface 118.

[0067] The terminal sealing portion 114 of the housing 100 is formed by filling and curing molten resin between an upper mold (movable mold) that moves open and close in the thickness direction of the connector terminal 117 and a lower mold (fixed mold) that does not move. Assuming that even if the upper mold is formed by making the portion of the forming surface corresponding to the mating surface 118 and the end 116a flat and in contact with the mating surface 118, a few percent of thermal shrinkage will occur in the resin, so the end 116a will be within tens of μm below the mating surface 118.

[0068] In this embodiment, the flush arrangement of the end 116a of the second surface 116 with the mating surface 118 includes not only cases where the end 116a of the second surface 116 and the mating surface 118 are arranged on completely identical planes, but also cases where the end 116a of the second surface 116 is positioned within tens of μm below the mating surface 118 in the direction opposite to the lead 350 (-Y-axis direction) in the thickness direction of the connector terminal 117. When the connector terminal 117 is cut by stamping or the like, edge collapse sometimes occurs at the edge of the mating surface 118. The end 116a of the second surface 116 is formed to be flush with most of the mating surface 118, except for the edge where the collapse occurs.

[0069] The second surface 116 has a middle portion 116b, which is located at the midpoint between adjacent connector terminals 117 in the width direction of the connector terminals 117. The middle portion 116b of the second surface 116 is configured to be positioned at a predetermined distance lower than the end 116a of the second surface 116 in the direction opposite to the lead 350 in the thickness direction of the connector terminals 117. This predetermined distance may be less than half the thickness of the connector terminals 117, for example, it may be more than one-third and less than half the thickness.

[0070] The second surface 116 has an inclined surface 116c that is inclined relative to the mating surface 118. The inclined surface 116c of the second surface 116 is inclined in the direction opposite to the lead wire 350 (-Y-axis direction) in the thickness direction of the connector terminal 117, moving away from the end 116a in the width direction of the connector terminal 117. The inclined surface 116c of the second surface 116 is formed between the end 116a and the middle portion 116b in the width direction of the connector terminal 117. Furthermore, the inclined surface 116c of the second surface 116 is formed on the outer portion 116d of the second surface 116 extending from the connector terminal 117a toward the side portion 123 in the width direction of the connector terminal 117. Similarly, the inclined surface 116c of the second surface 116 is formed on the outer portion 116e of the second surface 116 extending from the connector terminal 117b toward the side portion 124 in the width direction of the connector terminal 117.

[0071] That is, the second surface 116 located between adjacent connector terminals 117 has a groove 116f, the cross section of which is formed by the plane containing the connector terminal 117 in the thickness and width directions is V-shaped. The depth of the V-shaped groove 116f can be less than half the length of the connector terminal 117, for example, it can be more than one-third and less than half the length.

[0072] use Figure 9 and Figure 10 Explain the effects of this implementation method.

[0073] Figure 9 This is a diagram illustrating the physical quantity measuring device 20 of the comparative example. Figure 9 It corresponds to Figure 7 The image. Figure 10 yes Figure 9 An enlarged view of the area enclosed by the dotted line. Figure 10 It corresponds to Figure 8 The image.

[0074] In the comparative example physical quantity measuring device 20, the second surface 116 has an end portion 116a and a middle portion 116b with a height higher than the convex surface 116g of the mating surface 118. In the comparative example physical quantity measuring device 20, the housing 100, including the terminal sealing portion 114, has a linear expansion coefficient greater than that of the sealing member 250. Utilizing the difference in linear expansion coefficients between the housing 100 and the sealing member 250, thermal stress is generated in the terminal sealing portion 114 near the interface with the sealing member 250.

[0075] Specifically, when the housing 100 is formed using relatively inexpensive PBT resin and the sealing member 250 is formed using epoxy resin, the linear expansion coefficient of the housing 100 is 5 to 6 times that of the sealing member 250. In this case, if a heat load of -40°C to 130°C or lower is applied to the physical quantity measuring device 20 of the comparative example, the terminal sealing portion 114 of the housing 100 will... Figure 10 Significant thermal stress is generated near the interface with the sealing member 250, i.e., near the second surface 116, as shown in S1 and S2. Furthermore, due to this thermal stress, the connector terminal 117 sealed in the terminal sealing portion 114 and the sealing member 250 may peel off. If this peeling is significant, the lead wire 350 sealed in the sealing member 250 may break due to thermal fatigue. In other words, in the physical quantity measuring device 20 of the comparative example, it is difficult to ensure the connection reliability of the lead wire 350.

[0076] In contrast, in the physical quantity measuring device 20 of this embodiment, the height of the end portion 116a of the second surface 116 is the same as the height of the mating surface 118 of the connector terminal 117. That is, the end portion 116a of the second surface 116 is formed to be flush with the mating surface 118. As a result, the physical quantity measuring device 20 of this embodiment can reduce the volume of the terminal sealing portion 114 near the interface with the sealing member 250, thereby reducing the amount of thermal deformation of the terminal sealing portion 114.

[0077] Furthermore, in the physical quantity measuring device 20 of this embodiment, the thermal deformation of the terminal sealing portion 114 near the interface with the sealing member 250 is less likely to be limited by the connector terminal 117. For example, in the case where the second surface 116 has a convex surface 116g, as in the physical quantity measuring device 20 of the comparative example, when the terminal sealing portion 114 thermally shrinks, interference occurs near the convex surface 116g of the terminal sealing portion 114 with the mating surface 118, and the thermal shrinkage near the convex surface 116g is easily limited by the mating surface 118. In contrast, in the physical quantity measuring device 20 of this embodiment, the height of the end portion 116a of the second surface 116 is the same as the height of the mating surface 118, therefore, the thermal deformation of the terminal sealing portion 114 near the interface with the sealing member 250 is less likely to be limited by the connector terminal 117.

[0078] Therefore, even if the housing 100 is not made of an expensive resin material with a very small difference in linear expansion coefficient with the sealing member 250, the physical quantity measuring device 20 of this embodiment can suppress the thermal stress generated in the terminal sealing portion 114 near the interface with the sealing member 250. The physical quantity measuring device 20 of this embodiment can suppress the peeling between the connector terminal 117 and the sealing member 250, and can suppress the breakage of the lead wire 350 due to thermal fatigue. Therefore, the physical quantity measuring device 20 of this embodiment can easily ensure the connection reliability of the lead wire 350.

[0079] Furthermore, in the physical quantity measuring device 20 of this embodiment, as the second surface 116 moves away from the end 116a in the width direction of the connector terminal 117, the second surface 116 is inclined toward the side opposite to the lead 350 in the plate thickness direction of the connector terminal 117. That is, the second surface 116 has the inclined surface 116c as described above.

[0080] Assuming the second surface 116 is formed as a concave shape that descends in a stepped manner from the end 116a to the middle portion 116b, the forming surface of the upper mold has a convex portion corresponding to this concave shape. In this case, if the connector terminal 117 disposed between the upper and lower molds is misaligned, the convex portion of the upper mold is prone to gripping the connector terminal 117, thereby easily producing defective products and reducing productivity.

[0081] In the physical quantity measuring device 20 of this embodiment, since the second surface 116 has the inclined surface 116c as described above, the forming surface of the upper mold has an inclined surface corresponding to the inclined surface 116c. Because the forming surface of the upper mold has an inclined surface corresponding to the inclined surface 116c, the forming surface of the upper mold can restrict the position of the connector terminal 117 during forming, thereby suppressing positional deviation. Therefore, the physical quantity measuring device 20 of this embodiment can suppress the biting of the connector terminal 117 and suppress the reduction in productivity. Thus, the physical quantity measuring device 20 according to this embodiment can suppress the production cost of the housing 100 integrally formed with the connector terminal 117.

[0082] Furthermore, even when the linear expansion coefficient of the housing 100 is greater than that of the sealing member 250, the physical quantity measuring device 20 of this embodiment can suppress thermal stress generated in the terminal seal portion 114 near the interface with the sealing member 250. The physical quantity measuring device 20 of this embodiment can suppress peeling between the connector terminal 117 and the sealing member 250, and can suppress breakage of the lead wire 350 due to thermal fatigue.

[0083] Therefore, in the physical quantity measuring device 20 of this embodiment, the second surface 116 has an inclined surface 116c as described above, which can easily suppress the thermal stress generated in the terminal sealing portion 114 near the interface with the sealing member 250, thereby easily ensuring the connection reliability of the lead 350.

[0084] Specifically, in the physical quantity measuring device 20 of this embodiment, the second surface 116 located between adjacent connector terminals 117 has a V-shaped groove 116f. If we analyze the thermal stress generated near the interface between the terminal sealing portion 114 and the sealing member 250 of the housing 100 for this embodiment with the V-shaped groove 116f and the comparative example with the convex surface 116g, the thermal stress in this embodiment is about one-third that of the comparative example. Therefore, in the physical quantity measuring device 20 of this embodiment, the thermal stress generated in the terminal sealing portion 114 can be significantly suppressed, thereby ensuring sufficient reliability of the lead 350 connection.

[0085] Furthermore, in the physical quantity measuring device 20 of this embodiment, the depth of the V-shaped groove 116f can be more than one-third and less than one-half of the thickness of the connector terminal 117. If the depth of the V-shaped groove 116f is more than one-third of the thickness of the connector terminal 117, the effect of suppressing the thermal stress generated in the terminal sealing portion 114 is greater. If the depth of the V-shaped groove 116f is less than one-half of the thickness of the connector terminal 117, the amount of resin near the middle portion 116b of the terminal sealing portion 114 can be easily ensured, thus easily ensuring the strength near the middle portion 116b, and easily fixing the connector terminal 117. Therefore, the physical quantity measuring device 20 of this embodiment can effectively suppress the thermal stress generated in the terminal sealing portion 114, thereby ensuring the connection reliability of the lead 350, and can easily ensure the mechanical reliability of the terminal sealing portion 114 of the housing 100.

[0086] Furthermore, in the physical quantity measuring device 20 of this embodiment, the linear expansion coefficient of the housing 100 can be 5 times or more but less than 6 times the linear expansion coefficient of the sealing member 250. In other words, even if PBT resin is used in the housing 100 and epoxy resin is used in the sealing member 250, the physical quantity measuring device 20 can suppress the thermal stress generated in the terminal sealing portion 114 even if a resin material with a linear expansion coefficient of 5 times or more but less than 6 times that of the sealing member 250 is used in the housing 100. Thus, even if a relatively inexpensive resin material is used in the housing 100, the physical quantity measuring device 20 of this embodiment can suppress this thermal stress, thereby making it easier to ensure the connection reliability of the lead 350.

[0087] Furthermore, in the physical quantity measuring device 20 of this embodiment, the housing 100 has a front portion 121 on which the secondary passages 134 and 135 are formed, and a back portion 122 on the opposite side of the front portion 121 of the housing 100, and a second surface 116 is formed on the back portion 122. That is, in the measuring section 113 of the housing 100, the second surface 116 is formed on the back portion 122 on the opposite side of the front portion 121 on which the secondary passages 134 and 135 are formed.

[0088] In the molding die for the outer casing 100, the complex-shaped portions of the outer casing 100 tend to cling tightly to the die, therefore, they are typically formed using a lower die, which serves as a fixed die. Assuming that the upper die is opened while the formed outer casing 100 is clinging tightly to it, the molding die for the outer casing 100 would require a complex mechanism for removing the formed outer casing 100. In the outer casing 100 of this embodiment, the front portion 121 forming the sub-passages 134 and 135 corresponds to the complex-shaped portion; therefore, it is preferable that the front portion 121 is formed using the lower die.

[0089] In the physical quantity measuring device 20 of this embodiment, the second surface 116 is formed on the back surface 122 opposite to the front surface 121 where the secondary passages 134 and 135 are formed. Therefore, in the physical quantity measuring device 20 of this embodiment, the front surface 121 where the secondary passages 134 and 135 are formed can be formed by the lower mold, the connector terminal 117 can be placed in the lower mold, and the second surface 116 can be formed by the upper mold. Therefore, in the physical quantity measuring device 20 of this embodiment, the housing 100 can be formed appropriately without complicating the forming mold or forming process of the housing 100. Thus, the physical quantity measuring device 20 of this embodiment can further suppress the production cost of the housing 100, and therefore can more easily ensure the connection reliability of the lead 350.

[0090] use Figure 11 and Figure 12 A variation of this embodiment is described.

[0091] Figure 11 This is a diagram illustrating a modified example of the physical quantity measuring device 20 of this embodiment. Figure 11 It corresponds to Figure 7 The image. Figure 12 yes Figure 11 An enlarged view of the area enclosed by the dotted line. Figure 12 It corresponds to Figure 8 The image.

[0092] like Figure 7 and Figure 8As shown, in the physical quantity measuring device 20 of this embodiment, the second surface 116 located between adjacent connector terminals 117 has a V-shaped groove 116f. In contrast, in the modified physical quantity measuring device 20, as... Figure 11 and Figure 12 As shown, the second surface 116 located between adjacent connector terminals 117 can have a flat surface 116h. That is, in the modified physical quantity measuring device 20, the second surface 116 does not have an inclined surface 116c, and can be formed flush with the mating surface 118 not only at the end 116a, but also at the middle portion 116b. The end 116a and the middle portion 116b of the second surface 116 are defined as being flush with the mating surface 118 in the same manner as described above.

[0093] In the modified physical quantity measuring device 20, thermal stress generated in the terminal sealing portion 114 near the interface with the sealing member 250 can also be suppressed, thereby suppressing peeling between the connector terminal 117 and the sealing member 250. The modified physical quantity measuring device 20 can suppress the breakage of the lead 350 due to thermal fatigue, thereby easily ensuring the connection reliability of the lead 350.

[0094] <Other>

[0095] Furthermore, the present invention is not limited to the embodiments described above, and includes various modifications. For example, the above-described embodiments are detailed for ease of understanding and illustration of the present invention, and the present invention is not necessarily limited to including all the structures described. Additionally, a portion of the structure of one embodiment may be replaced with a structure of another embodiment, and a structure of another embodiment may be added to the structure of one embodiment. Furthermore, a portion of the structure in each embodiment may be added to, deleted from, or replaced with other structures.

[0096] Label Explanation

[0097] 2… Measured gas, 20… Physical quantity measuring device, 22… Main passage, 100… Housing, 115… First surface, 116… Second surface, 116a… End, 116f… Groove, 117… Connector terminal, 118… Mating surface, 119… Side, 121… Front side, 122… Back side, 134, 135… Secondary passage, 250… Sealing member, 310… Chip package (sensor), 331… Temperature sensor (sensor), 333… Humidity sensor (sensor), 335… Pressure sensor (sensor), 350… Lead wire.

Claims

1. A physical quantity measuring device, characterized in that, include: A housing that houses the sensor used to measure physical quantities; The terminal is sealed within the housing; A lead wire that engages with the terminal; as well as A sealing member that seals the lead and contacts the terminal and the housing, respectively. The linear expansion coefficient of the outer shell is greater than that of the sealing member. The terminal has a mating surface that engages the lead and contacts the sealing member, and a side surface that is continuous with the mating surface and sealed within the housing. The housing has a first surface that contacts the side of the terminal, and a second surface that is continuous with the first surface and contacts the sealing member. The end of the second surface, which is continuous with the first surface, is formed to be flush with the mating surface. The second surface is inclined toward the side opposite to the lead in the thickness direction of the terminal as it moves away from the end in the width direction of the terminal.

2. The physical quantity measuring device as described in claim 1, characterized in that, The terminal is composed of a plurality of terminals arranged at intervals in the width direction of the terminal. The second surface located between adjacent terminals has a groove, the cross-section of which is formed in a V-shape by a plane that is cut by the thickness and width directions of the plate containing the terminal.

3. The physical quantity measuring device as described in claim 2, characterized in that, The depth of the groove is more than one-third and less than one-half of the thickness of the terminal plate.

4. The physical quantity measuring device as described in claim 1, characterized in that, The linear expansion coefficient of the outer casing is more than 5 times and less than 6 times the linear expansion coefficient of the sealing member.

5. The physical quantity measuring device as described in claim 1, characterized in that, It has a secondary passage for drawing in a portion of the gas being measured that flows through the main passage. The housing has a front portion on which the secondary passage is formed, and a back portion on the opposite side of the front portion of the housing. The second surface is formed on the back side.

Images