DETECTION DEVICE FOR PHYSICAL QUANTITIES

Abstract

Physical quantity detection device (20) comprising the following: a semiconductor element with a flow rate detection unit (205); a printed circuit board (207) that supports the semiconductor element; and a conductive base element that secures the printed circuit board (207), wherein the semiconductor element is attached to the circuit board (207) such that the flow rate detection unit (205) faces the base element, either the circuit board (207) is provided with a masking opening (207b) in which a conductor is exposed, and a projection (202a) provided on the base element is in contact with the conductor exposed by the cover lacquer opening (207b); or the circuit board (207) is provided with a through hole (207c) that penetrates the circuit board (207), and a projection (253) provided on the base element and the through hole (207c) are attached to each other; or the circuit board (207) is provided with a solder pad, and the solder pad and the base element come into contact with each other.

Description

Technical area

[0001] The present invention relates to a physical quantity detection device that detects a physical quantity of, for example, the intake air of an internal combustion engine. Technical background

[0002] For example, PTL 1 discloses a structure in which a conductor is formed on an inner wall surface of a through-hole formed by penetrating the front and back surfaces of a substrate and is electrically connected to a substrate conductor portion.

[0003] PTL 2 discloses a physical quantity detection device that can prevent heat from being applied to a sensor due to downsizing. List of citationsPatent literature PTL 1: JP 2002-357467 A PTL 2: DE 11 2018 003 485 T5 Summary of the inventionTechnical problem

[0004] The conventional device described above has the conductor in the through-hole formed in the substrate to improve corrosion resistance, but does not contribute to improving the corrosion resistance of a sensor element itself. A sensor that measures the flow rate of intake air drawn into an internal combustion engine needs to be improved in corrosion resistance and downsized to reduce pressure loss.

[0005] The present invention has been made in view of the above points, and its object is to provide a compact air flow rate measuring device with improved corrosion resistance. Solution to the problem

[0006] A physical quantity detection device of the present invention that solves the above problems includes: a semiconductor element having a flow rate detection unit; a circuit board that supports the semiconductor element; and a conductive base member that fixes the circuit board. The semiconductor element is fixed to the circuit board so that the flow rate detection unit faces the base member, and either the circuit board is provided with a resist opening in which a conductor is exposed, and a projection provided on the base member is in contact with the conductor exposed by the resist opening; or the circuit board is provided with a through-hole penetrating the circuit board, and a projection provided on the base member and the through-hole are fixed to each other; or the circuit board is provided with a soldering pad, and the soldering pad and the base member come into contact with each other. Advantageous effects of the invention

[0007] According to the present invention, it is possible to obtain a compact physical quantity detection device with high corrosion resistance.

[0008] Another feature related to the present invention will become apparent from the description of the present specification and the accompanying drawings. In addition, other objects, configurations, and effects will become apparent from the following description of the embodiments. Brief description of the drawings Fig. 1 is a system diagram illustrating an embodiment in which a physical quantity detecting device according to the present invention is used in an internal combustion engine control system. Fig. 2A is a front view of the physical quantity detection device. Fig. Figure 2B is a right side view of the physical quantity detection device. Fig. 2C is a rear view of the physical quantity detection device. Fig. 2D is a view of the left side of the physical quantity detection device. Fig. 2E is a plan view of the physical quantity detection device Fig. 2F is a bottom view of the physical quantity detection device. Fig. 3A is a line IIIA-IIIA to Fig. 2D cross-sectional view. Fig. 3B is a line IIIB-IIIB to Fig. Cross-sectional view taken in Figure 2A. Fig. 3C is a line IIIC-IIIC to Fig. Cross-sectional view taken in Figure 2A. Fig. 3D is a front view of a case with only one cover removed. Fig. Figure 4A is a front view of the housing with a cover assembly removed. Fig. 4B is a line IVB-IVB to Fig. Cross-sectional view taken in Figure 4A. Fig. 5 is a view illustrating a configuration of the cover assembly. Fig. Figure 6A is a front view of a printed circuit board on which a chip assembly and circuit components are mounted. Fig. 6B is a line VIB-VIB to Fig. Cross-sectional view taken in Figure 6A. Fig. 6C is a line along the VIC-VIC to Fig. Cross-sectional view taken in Figure 6A. Fig. Figure 7A is a front view of the chip assembly. Fig. Figure 7B is a rear view of the chip assembly. Fig. Figure 7C is a side view of the chip assembly. Fig. 7D is a bottom view of the chip assembly. Fig. Figure 7E is an isometric view of the chip assembly. Fig. 8 is a view illustrating a bent shape of a connection terminal according to the present embodiment. Fig. 9 is a view illustrating a bent shape of a connection terminal according to a comparative example. Fig. 10A is a line along the XA-XA to Fig. 5 taken cross-sectional view. Fig. 10B is an enlarged view of XB in Fig. 10A. Fig. 11 is a view illustrating a back side of the cover. Fig. Fig. 12A is a view illustrating another embodiment of a support structure of the circuit board, and is the Fig. 10A corresponding view. Fig. Figure 12B is an enlarged view of XIIB in Fig. 12A. Fig. Fig. 13A is a view illustrating still another embodiment of the support structure of the printed circuit board, and is the Fig. 10A corresponding view. Fig. 13B is an enlarged view of XIIIB in Fig. 13A. Fig. Fig. 14 is a view for describing another embodiment of the printed circuit board and is the Fig. 5 corresponding view. Fig. Fig. 15 is a view for describing still another embodiment of the printed circuit board and is the Fig. 5 corresponding view. Fig. Fig. 16 is a view for describing another embodiment of the cover assembly and is the Fig. 5 corresponding view. Description of the embodiments

[0009] A mode for carrying out the invention to be described later (hereinafter, an embodiment) solves various problems desired to be solved as an actual product, and particularly solves various types of problems desired for use as a detection device that detects a physical quantity of intake air of a vehicle and achieves various effects. One of the various problems to be solved by the following embodiment corresponds to the content described in the above-described "Technical Problem" section. In addition, one of the various effects to be achieved by the following embodiment corresponds to the effect described in the above-described "Advantageous Effects of the Invention" section.The various problems to be solved by the following embodiment and the various effects to be achieved by the following embodiment will be described in the description of the following embodiment. Accordingly, the problems and advantages to be solved and achieved by the following embodiment will also be described, except for the content in the "Technical Problem" section and the content in the "Advantageous Effects of the Invention" section.

[0010] In the following embodiment, the same reference numerals represent the same configurations and achieve the same effects even under different drawing numbers. There is also a case where only one reference numeral is given to a figure for a configuration that has already been described in a drawing, and the description thereof is omitted.

[0011] Fig. 1 is a system diagram illustrating the embodiment in which the physical quantity detection device according to the present invention is used in an electronic control system 1 for fuel injection-type internal combustion engines. Intake air is drawn from an air cleaner 21 as a measurement gas 2 based on the operation of an internal combustion engine 10 including an engine cylinder 11 and an engine piston 12, and is introduced into a combustion chamber of the engine cylinder 11 via, for example, an intake body such as a main passage 22, a throttle body 23, and an intake manifold 24. A physical quantity of the measurement gas 2, which is the intake air supplied to the combustion chamber, is detected by a physical quantity detection device 20 according to the present invention.Based on the detected physical quantity, fuel is supplied through a fuel injection valve 14 and guided to the combustion chamber as an air-fuel mixture with the measurement gas 2. Incidentally, in the present embodiment, the fuel injection valve 14 is provided at an intake port of the internal combustion engine, and the fuel injected into the intake port, together with the measurement gas 2, forms the air-fuel mixture. The air-fuel mixture is guided into the combustion chamber via an intake valve 15 and burned to generate mechanical energy.

[0012] The fuel and air supplied into the combustion chamber form a mixed state of fuel and air and are explosively combusted by the spark ignition of a spark plug 13, thereby generating mechanical energy. After combustion, the gas is guided from an exhaust valve 16 into an exhaust pipe and is discharged from the exhaust pipe to the outside of a vehicle as exhaust gas 3. A flow rate of the measurement gas 2 as the intake air supplied to the combustion chamber is controlled by a throttle valve 25, the opening degree of which is changed based on an operation of an accelerator pedal.A supply amount of the fuel is controlled based on the flow rate of intake air supplied to the combustion chamber, whereby a driver can control the mechanical energy generated by the internal combustion engine by controlling the opening degree of the throttle valve 25 and controlling the flow rate of intake air supplied to the combustion chamber. <Overview of the internal combustion engine control system>

[0013] The physical quantity, such as the flow rate, temperature, humidity, and pressure, of the measurement gas 2, which is the intake air taken from the air cleaner 21 and flowing in the main passage 22, is detected by the physical quantity detection device 20. An electrical signal indicative of the physical quantity of the intake air is input from the physical quantity detection device 20 to a control device 4. In addition, an output of a throttle angle sensor 26, which measures the opening degree of the throttle valve 25, is input to the control device 4. Furthermore, an output of a rotation angle sensor 17 is input to the control device 4 to measure a position or state of the engine piston 12, the intake valve 15, or the exhaust valve 16 of the internal combustion engine, and the rotational speed of the internal combustion engine.An output of an oxygen sensor 28 is input to the control device 4 to measure a state of a mixture ratio between the fuel amount and the air amount based on the state of the exhaust gas 3.

[0014] The control device 4 calculates a fuel injection amount and ignition timing based on the physical quantity of intake air as the output of the physical quantity detection device 20 and the engine speed measured based on the output of the rotation angle sensor 17. Based on these calculation results, the fuel amount to be supplied from the fuel injection valve 14 and the ignition timing for igniting the spark plug 13 are controlled. Practically, the fuel supply amount and ignition timing are further finely controlled based on a change in temperature or throttle angle detected by the physical quantity detection device 20, a change in engine speed, and an air-fuel ratio measured by the oxygen sensor 28.The control device 4 further controls the amount of air bypassing the throttle valve 25 using an idle air control valve 27 in an idling operating state of the internal combustion engine and controls the rotational speed of the internal combustion engine in the idling operating state.

[0015] Both the fuel supply amount and the ignition timing, which are key control variables of the internal combustion engine, are calculated using the output of the physical quantity detection device 20 as the main parameters. Accordingly, improving the detection accuracy of the physical quantity detection device 20, suppressing changes over time, and improving reliability are important in terms of improving the control accuracy of a vehicle and ensuring reliability.

[0016] Particularly recently, the demand for fuel economy of vehicles has increased dramatically, and the demand for exhaust gas purification has also increased dramatically. To respond to such demands, it is very important to improve the detection accuracy of the physical quantity of the measurement gas 2, which is the intake air, detected by the physical quantity detection device 20. In addition, it is also important that the physical quantity detection device 20 maintains high reliability.

[0017] A vehicle equipped with the physical quantity detection device 20 is used in an environment where a change in temperature or humidity is large. It is desirable that the physical quantity detection device 20 be configured taking into account the response to such a change in temperature or humidity in the use environment and the response to dust, contaminants, and the like.

[0018] In addition, the physical quantity detection device 20 is mounted on the intake pipe, which is affected by the heat generated by the internal combustion engine. Consequently, the heat generated by the internal combustion engine is transferred to the physical quantity detection device 20 via the intake pipe serving as the main passage 22. The physical quantity detection device 20 detects the flow rate of the measurement gas 2 by performing heat transfer with the measurement gas 2. Therefore, it is important to suppress the influence of external heat as much as possible.

[0019] The physical quantity detection device 20 installed in the motor vehicle not only solves the problem described in the Technical Problem section and achieves the effects described in the Advantageous Effects of the Invention section, as described later, but also solves various problems and achieves various effects required by the product, as described later, by sufficiently considering the various problems described above. The specific problems to be solved and the specific effects to be achieved by the physical quantity detection device 20 will be described in the following description of the embodiment. <Erscheinungsstruktur der Detektionsvorrichtung physikalischer Größen>

[0020] The Fig. Figures 2A to 2F are views illustrating the appearance of the physical quantity detection device. Incidentally, the following description assumes that the measurement gas flows along the central axis of the main channel.

[0021] The physical quantity detection device 20 is used by being inserted into the main channel 22 through a mounting hole provided in a channel wall of the main channel 22. The physical quantity detection device 20 includes a housing 201 and a cover 202 fixed to the housing 201. The housing 201 is formed by injection molding a synthetic resin material. The cover 202 is formed, for example, using a plate-shaped member made of a conductive material such as an aluminum alloy, and in the present embodiment, is formed using a compression-molded product made of an aluminum alloy. The cover 202 is formed in a thin plate shape and has a wide, flat cooling surface.

[0022] The housing 201 includes: a flange 211 configured to fix the physical quantity detection device 20 to the inlet body as the main channel 22; a connector 212 protruding from the flange 211 and exposed from the inlet body to the outside to realize electrical connection with an external device; and a measuring unit 213 extending so as to protrude from the flange 211 toward the center of the main channel 22.

[0023] The measuring unit 213 has a thin and long shape extending from the flange 211 toward the center of the main channel 22, and includes a wide front surface 221 and a wide rear surface 222, and a pair of narrow side surfaces 223 and 224. The measuring unit 213 protrudes from an inner wall of the main channel 22 toward a channel center of the main channel 22 in a state where the physical quantity detection device 20 is attached to the main channel 22. Then, the front surface 221 and the rear surface 222 are arranged in parallel along the central axis of the main channel 22.Between the narrow side surfaces 223 and 224 of the measuring unit 213, the side surface 223 on one side of the measuring unit 213 is arranged in the transverse direction to face the upstream side of the main channel 22, while the side surface 224 on the other side of the measuring unit 213 is arranged in the transverse direction to face the downstream side of the main channel 22. In the state where the physical quantity detection device 20 is attached to the main channel 22, a distal end portion of the measuring unit 213 serves as a bottom surface 226.

[0024] Because a sub-channel inlet 231 is provided at the distal end portion of the measuring unit 213, extending from the flange 211 toward the center of the main channel 22 in the physical quantity detection device 20, a gas can be taken into a sub-channel in a portion near the center portion away from an inner wall surface, rather than in the vicinity of the inner wall surface of the main channel 22. Consequently, the physical quantity detection device 20 can measure the flow rate of the gas in the portion away from the inner wall surface of the main channel 22 and suppress a decrease in measurement accuracy caused by the influence of heat or the like.

[0025] The area surrounding the inner wall surface of the main channel 22 is easily affected by the temperature of the main channel 22, so the temperature of the measurement gas 2 differs from the original gas temperature, which is different from the average state of the main gas in the main channel 22. In particular, when the main channel 22 is the intake body of the engine, it is often maintained at a high temperature due to the influence of heat from the engine. Consequently, the gas temperature around the inner wall surface of the main channel 22 is often higher than the original temperature of the main channel 22, resulting in a decrease in measurement accuracy. In addition, fluid resistance around the inner wall surface of the main channel 22 is large, and the flow velocity becomes lower than the average flow velocity of the main channel 22.Consequently, if the gas in the vicinity of the inner wall surface of the main channel 22 is taken into the sub-channel as the measurement gas 2, there is a possibility that the decrease in flow velocity with respect to the average flow velocity of the main channel 22 results in a measurement error.

[0026] Because the physical quantity detection device 20 is provided with the sub-channel inlet 231 at the distal end portion of the thin and long measuring unit 213 extending from the flange 211 toward the center of the main channel 22, it is possible to reduce the measurement error related to the decrease in flow velocity in the vicinity of the inner wall surface. In addition, not only the sub-channel inlet 231 is provided at the distal end portion of the measuring unit 213 extending from the flange 211 toward the center of the main channel 22, but also a first outlet 232 and a second outlet 233 of the sub-channel are provided at the distal end portion of the measuring unit 213 in the physical quantity detection device 20, thus further reducing the measurement error.

[0027] The physical quantity detecting device 20 has a shape in which the measuring unit 213 extends to be long along the axis from an outer wall of the main channel 22 toward the center, with the widths of the side surfaces 223 and 224 having a narrow shape, as shown in FIGS. Fig. 2B and Fig. 2D. As a result, the physical quantity detection device 20 can suppress the fluid resistance of the measurement gas 2 to a small value. <Struktur der Temperaturdetektionseinheit>

[0028] In the physical quantity detection device 20, an intake air temperature sensor 203, which is a temperature detection unit, is provided in the measuring unit 213, as shown in Fig. 2B. The intake air temperature sensor 203 is arranged in the center of a channel of a temperature detection channel C, which has one end 238 open near the sub-channel inlet 231 and another end 239 open toward the rear side 222 of the measuring unit 213. The temperature detection channel C is formed by the housing 201 and the cover 202.

[0029] As in Fig. As illustrated in Figure 6A, the intake air temperature sensor 203 is formed of an axial line component including a columnar sensor body 203a and a pair of leads 203b projecting from both axial end portions of the sensor body 203a in directions away from each other. The intake air temperature sensor 203 is mounted on a circuit board 207 in the measurement unit 213 via the leads 203b, and the sensor body 203a is arranged so as to be orthogonal to the flow direction of the measurement gas 2 in the temperature detection channel C.

[0030] Because the intake air temperature sensor 203 is arranged in the temperature detection channel C formed by the case 201 and the cover 202, it is possible to prevent the intake air temperature sensor 203 from coming into direct contact with another object and being damaged during transportation or fixing work of the physical quantity detection device 20.

[0031] According to the physical quantity detection device 20 of the present embodiment, the intake air temperature sensor 203 is arranged on the upstream side of the measurement unit 213, and thus it is possible to bring the measurement gas 2 flowing straight from the upstream side into direct contact with the intake air temperature sensor 203. Therefore, the heat dissipation characteristics of the intake air temperature sensor 203 can be improved. <Struktur des Flansches>

[0032] The measuring unit 213 of the physical quantity detection device 20 is inserted inside through the mounting hole provided in the main channel 22, with the flange 211 of the physical quantity detection device 20 abutting against the main channel 22 and being fixed to the main channel 22 with a screw. The flange 211 has a substantially rectangular shape with a predetermined plate thickness in a plan view, with a pair of mounting holes 241 provided at diagonal corners, as shown in FIGS. Fig. 2E and Fig. 2F. The mounting hole 241 has a through hole 242 penetrating the flange 211. The flange 211 is secured to the main channel 22 by inserting a mounting screw (not shown) into the through hole 242 of the mounting hole 241 and screwing the screw into a screw hole of the main channel 22.

[0033] As in Fig. 2E, a plurality of ribs are provided on the top surface of the flange 211. The ribs include: a first rib 243 linearly connecting the mounting hole 241 and the connector 212; a second rib 244 with a tapered cross section surrounding the periphery of the through-hole 242 of the mounting hole 241; a third rib 245 provided along an outer peripheral portion of the flange 211; and a fourth rib 246 extending on a diagonal of the flange 211 in a direction intersecting the first rib 243.

[0034] The first rib 243 is provided linearly between the mounting hole 241, which is subjected to a screw fastening force on the main channel 22, and the connector 212, which has a relatively high rigidity due to its three-dimensional shape. Consequently, a flange reinforcement effect is high. Therefore, compared to the one without the first rib 243, the thickness of the flange 211 can be reduced, the weight of the entire housing can be reduced, and it is possible to reduce the influence of shrinkage of the resin forming the flange 211 during molding of the housing 201.

[0035] As in Fig. As illustrated in Figure 2E, the connector 212 is provided with four external terminals 247 and the correction terminals 248 therein. The external terminals 247 serve as a terminal for outputting a physical quantity, such as a flow rate and a temperature, which is a measurement result of the physical quantity detection device 20, and a power supply terminal for supplying DC power for operating the physical quantity detection device 20.

[0036] The correction terminal 248 is a terminal used to measure the manufactured physical quantity detection devices 20, obtain a correction value for each of the physical quantity detection devices 20, and store the correction value in a memory within the physical quantity detection device 20. In the subsequent measurement operation of the physical quantity detection device 20, the correction data representing the above-described correction value stored in the memory is used, and the correction terminal 248 is not used.

[0037] Therefore, the correction terminal 248 has a different shape than that of the external terminal 247 so that the correction terminal 248 does not interfere when the external terminal 247 is connected to another external device. In the present embodiment, the correction terminal 248 has a shorter shape than the external terminal 247 so as not to interfere with the connection even when a connection terminal to the external device connected to the external terminal 247 is inserted into the connector 212. <Gesamtstruktur des Gehäuses>

[0038] Fig. 3A is a line IIIA-IIIA to Fig. 2D cross-sectional view, Fig. 3B is a line IIIB-IIIB to Fig. 2A taken cross-sectional view, Fig. 3C is a line IIIC-IIIC to Fig. 2A taken cross-sectional view and Fig. 3D is a front view of a case with only the cover removed.

[0039] As in Fig. As illustrated in Fig. 3D, the housing 201 is provided with a sub-channel groove 250 configured to form the sub-channel 234 and a circuit chamber 235 configured to accommodate the circuit board 207. The circuit chamber 235 and the sub-channel groove 250 are provided so as to be recessed on the front side of the measurement unit 213. The circuit chamber 235 is provided in a region on one side in the transverse direction (on the side surface 223 side) of the main channel 22, which is located on the upstream side in the flow direction of the measurement gas 2.Then, the sub-channel groove 250 is provided over a region located closer to the distal end side (the bottom surface 226 side) than the circuit chamber 235 in the longitudinal direction of the measuring unit 213, and a region located closer to the other side (the side surface 224 side) than the circuit chamber 235 in the transverse direction of the main channel 22, which is on the downstream side in the flow direction of the measurement gas 2.

[0040] The sub-channel groove 250, in cooperation with the cover 202, forms a sub-channel 234. The sub-channel groove 250 has a first sub-channel groove 251 and a second sub-channel groove 252 branching off in the middle of the first sub-channel groove 251. The first sub-channel groove 251 is formed to extend along the transverse direction of the measuring unit 213 between the sub-channel inlet 231, which is open on the side surface 223 on one side of the measuring unit 213, and the first outlet 232, which is open on the side surface 224 on the other side of the measuring unit 213. The first sub-channel groove 251 forms a first sub-channel A, which receives the measurement gas 2 flowing in the main channel 22 from the sub-channel inlet 231 and returns the received measurement gas 2 to the main channel 22 from the first outlet 232. The first sub-channel A extends from the sub-channel inlet 231 along the flow direction of the measuring gas 2 in the main channel 22 and is connected to the first outlet 232.

[0041] The second sub-channel groove 252 branches off at an intermediate position of the first sub-channel groove 251, is bent toward one side of the proximal end portion (flange side) of the measuring unit 213, and extends along the longitudinal direction of the measuring unit 213. Then, the second sub-channel groove 252 is bent at the proximal end portion of the measuring unit 213 toward the other side (side surface 224 side) in the transverse direction of the measuring unit 213, making a U-turn toward the distal end portion of the measuring unit 213, and extends again along the longitudinal direction of the measuring unit 213. Then, the second sub-channel groove 252 is bent in front of the first outlet 232 toward the other side in the transverse direction of the measuring unit 213, being provided to be continuous with the second outlet 233 open to the side surface 224 on the other side of the measuring unit 213.The second outlet 233 is arranged to face the downstream side in the flow direction of the measurement gas 2 in the main channel 22. The second outlet 233 has an opening area substantially equal to or slightly larger than that of the first outlet 232 and is formed at a position closer to the proximal end portion side in the longitudinal direction of the measurement unit 213 than the first outlet 232.

[0042] The second sub-channel groove 252 forms a second sub-channel B, which allows the measurement gas 2, after branching and flowing from the first sub-channel A, to pass through it to return the measurement gas 2 from the second outlet 233 to the main channel 22. The second sub-channel B has a path that reciprocates along the longitudinal direction of the measurement unit 213.That is, the second sub-channel B has a path that branches off in the middle of the first sub-channel A, extends toward the proximal end portion side of the measuring unit 213, folds back on the proximal end portion side of the measuring unit 213 to extend toward the distal end portion side of the measuring unit 213, and leads to the second outlet 233, which is arranged on the downstream side of the sub-channel inlet 231 in the main channel 22 in the flow direction of the measurement gas 2, so as to face the downstream side in the flow direction of the measurement gas 2. The second sub-channel B has a flow rate detection unit 205 arranged at an intermediate position thereof.Because the second sub-channel B is formed to extend and reciprocate along the longitudinal direction of the measuring unit 213, the length of the channel can be ensured to be longer, and the influence on the flow rate detection unit 205 when pulsation occurs in the main channel can be reduced.

[0043] According to the above configuration, the physical quantity detection device 20 can include the sub-channel 234 with a sufficient length. Therefore, the physical quantity detection device 20 can measure the physical quantity of the measurement gas 2 with high accuracy while suppressing the fluid resistance to a small value.

[0044] The first sub-channel A is provided so as to extend from the sub-channel inlet 231 along the transverse direction of the measuring unit 213 to the first outlet 232. Consequently, a foreign matter such as dust that has entered the first sub-channel A from the sub-channel inlet 231 can be directly discharged from the first outlet 232. Therefore, it is possible to prevent the foreign matter from entering the second sub-channel B and prevent the flow rate detection unit 205 in the second sub-channel B from being affected.

[0045] The sub-channel inlet 231 and the first outlet 232 of the first sub-channel groove 251 have a larger opening area at the sub-channel inlet 231 than at the first outlet 232. Because the opening area of ​​the sub-channel inlet 231 is larger than that of the first outlet 232, the measurement gas 2 that has flowed into the first sub-channel A can be reliably guided to the second sub-channel B branching off in the middle of the first sub-channel A.

[0046] At the sub-channel inlet 231 of the first sub-channel groove 251, a protrusion 253 is provided at a center position in the longitudinal direction. The protrusion 253 divides a size of the sub-channel inlet 231 into two equal parts in the longitudinal direction, causing each part to have a smaller opening area than the first outlet 232 and the second outlet 233. The protrusion 253 regulates a size of the foreign matter that can penetrate from the sub-channel inlet 231 into the first sub-channel A only to a size smaller than the first outlet 232 and the second outlet 233, and can prevent the first outlet 232 and the second outlet 233 from being blocked by the foreign matter. <Struktur des einzigen Gehäuses>

[0047] Fig. 4A is a front view of the housing from which a cover assembly has been removed, and Fig. 4B is a line IVB-IVB to Fig. Cross-sectional view taken in Figure 4A.

[0048] As in Fig. As illustrated in Figure 4A, the housing 201 is provided with the ribs 237 on a bottom surface of the circuit chamber 235. The ribs 237 include a plurality of vertical ribs extending along the longitudinal direction of the measuring unit 213 and a plurality of horizontal ribs extending along the transverse direction of the measuring unit 213, and are provided in a grid pattern.

[0049] Because the measuring unit 213 is provided with the ribs 237, the housing 201 can achieve high rigidity without increasing its thickness. The thickness of the housing 201 differs greatly between the flange 211 and the measuring unit 213, and the difference in heat shrinkage after injection molding is large, and the measuring unit 213, which is thinner than the flange 211, is easily deformed. Therefore, by providing the lattice-shaped ribs extending in a flat shape on the bottom surface of the circuit chamber 235, it is possible to suppress the deformation of the measuring unit 213 at the time of heat shrinkage.

[0050] The casing 201 is provided with ribs 237 not on an outer wall of the measuring unit 213, but on the bottom surface of the circuit chamber 235. If they are provided on the outer wall of the measuring unit 213, there is a possibility that the ribs 237 are affected by the flow of the measurement gas 2 passing through the main channel 22. For example, if the depth of the circuit chamber 235 is determined assuming that the single-side mounting circuit board 207 is accommodated, the depth of the circuit chamber 235 must be increased if the specifications are changed to accommodate the double-side mounting circuit board 207. However, if the ribs are provided on the outer wall of the measuring unit 213, the ribs protrude due to an increase in the depth of the circuit chamber 235, so the thickness of the measuring unit 213 increases.Therefore, the thickness of the measuring unit 213 is different between the single-sided mounting and the double-sided mounting, which is likely to affect the detection accuracy.

[0051] On the other hand, in the present embodiment, the ribs 237 are provided on the bottom of the circuit chamber 235, thus making it possible to prevent the influence on the flow of the measurement gas 2 passing through the main channel 22 and allow the measurement gas 2 to flow smoothly. Then, the depth of the bottom of the circuit chamber 235 can be changed simply by changing the height of the rib 237 in the circuit chamber 235, and regardless of whether the circuit board 207 is single-sided mounting or double-sided mounting, it is unnecessary to change the thickness of the measurement unit. <Struktur der Abdeckungsanordnung>

[0052] Fig. 5 is a view illustrating a configuration of the cover assembly.

[0053] The cover assembly is formed by the cover 202, which is a conductive base member, and the circuit board 207 on which a chip package 208 is mounted. The cover 202 is formed using a conductive metal material, such as an aluminum alloy, a stainless alloy, or the like, but may be made of, for example, a conductive resin material, without being limited to a metal. The cover 202 is a flat plate member with a size that covers the front surface of the measuring unit 213 and is fixed to the measuring unit 213 with an adhesive. In addition, the cover 202 covers the circuit chamber 235 of the measuring unit 213 and forms a sub-channel in cooperation with the sub-channel groove 250 of the measuring unit 213.

[0054] The cover 202 forms part of the sub-channel 234. The dust that has flowed into the sub-channel 234 along with the measurement gas 2 flows along the back of the cover 202. The cover 202 has a fixed potential, and the dust that passes through the back of the cover 202 is electrostatically eliminated, and the adhesion of the dust to the flow rate detection unit 205 can be suppressed, thus improving corrosion resistance. The cover 202 forms the sub-channel 234 and is a necessary component regardless of the presence or absence of static elimination, so an additional component for static elimination is unnecessary.

[0055] The circuit board 207 on which the chip assembly 208 is mounted is fixed to the back surface of the cover 202, that is, to the surface to be fixed to the housing 201. The circuit board 207 is formed, for example, using a glass epoxy circuit board (glass epoxy plate) and has a rectangular shape extending along the longitudinal direction of the measuring unit 213. A notch is provided at a center position in the longitudinal direction of the circuit board 207, and a receiving portion 207a is configured to receive a part of the chip assembly 208. The chip assembly 208 is fixed to the circuit board 207 at the center position in the longitudinal direction of the circuit board 207 in a state of protruding laterally from one end portion along the transverse direction of the circuit board 207.

[0056] The cover assembly accommodates the circuit board 207 in the circuit chamber 235 by attaching the cover 202 to the housing 201 and allows the chip assembly 208 to extend between the sub-channel 234 and the circuit chamber 235 so that the flow rate detection unit 205 of the chip assembly 208 can be arranged in the second sub-channel B. <Dichtungsstruktur in der Schaltungskammer>

[0057] In the circuit chamber 235, a hatched section in Fig. 3D glued to the cover 202 with an adhesive. As in Fig. As illustrated in Figure 3A, the front side of the circuit board 207 is hermetically divided into three spaces R1, R2, and R3 in the circuit chamber 235. Specifically, the first space R1, to which a connector terminal 214 integrally molded with the housing 201 and a contact pad 265 of the circuit board 207 are connected, the second space R2 for accommodating a pressure sensor 204 and a part of the chip assembly 208, and a third space R3 in which a temperature and humidity sensor 206 is housed and the lead 203b of the intake air temperature sensor 203 is inserted, are formed.

[0058] The first space R1 is sealed by the cover 202 on the front side and is open through an opening 227 of the housing 201 on the back side, as shown in Fig. 2C. However, the opening 227 is filled with a resin material after the connector terminal 214 and the contact surface 265 of the circuit board 207 are electrically connected by a bonding wire 266. That is, the first space R1 is a hermetically sealed space insulated from the outside of the measurement unit 213 by sealing the front and back surfaces. Therefore, a connection portion between the connector terminal 214 and the contact surface 265 can be prevented from coming into contact with a gas contained in the measurement gas 2 and corroding.

[0059] The second space R2 communicates with the sub-channel 234 through a gap between the second space R2 and the cover 202. The pressure sensor 204 is mounted on the circuit board 207 at a position located in the second space R2. Therefore, the pressure sensor 204 can measure the pressure in the second space R2. The third space R3 communicates with the temperature detection channel C and communicates with the outside of the measuring unit 213 via an R3 inlet 255. The temperature and humidity sensor 206 is mounted on the circuit board 207 at a position located in the third space R3. Therefore, the temperature and humidity sensor 206 can measure the temperature and humidity in the third space R3. <Struktur der Leiterplatte>

[0060] Fig. 6A is a front view of the circuit board on which the chip assembly and circuit components are mounted, Fig. 6B is a line VIB-VIB to Fig. 6A taken cross-sectional view and Fig. 6C is a line along the VIC-VIC to Fig. Cross-sectional view taken in Figure 6A.

[0061] The circuit board 207 has a rectangular shape along the longitudinal direction of the measuring unit 213 as a whole. The circuit board 207 has a receiving portion 207a configured to receive a part of the chip assembly 208. As shown in Fig. 7A, the receiving portion 207a is formed by partially cutting out a portion of the circuit board 207 that is biased toward the center in the longitudinal direction and toward one side in the transverse direction (notch portion), the circuit board 207 having a substantially U-shape in a plan view.

[0062] In the chip package 208, at least a part of a package body 271 enters the receiving portion 207a of the circuit board 207 in the thickness direction to be housed therein. Specifically, the package body 271 is housed in a state in which a front side portion 271c of the package, which is a proximal end portion 271a of the package body 271, and a portion of the package body 271 on which the flow rate detection unit 205 is provided, enter the receiving portion 207a of the circuit board 207, as shown in FIGS. Fig. 6B and Fig. 6C is illustrated.

[0063] Because, in the present embodiment, the front portion 271c of the package, which is a part of the package body 271 in the thickness direction, is housed in the receiving portion 207a of the circuit board 207, the overall mounting height, including the thickness of the chip package 208 and the height of the terminal, can be suppressed. As a result, for example, the mounting height can be reduced to the same as that of the small pressure sensor mounted together with the chip package 208 on the circuit board 207. In addition, the mounting height of the mounting components can be suppressed, so that it is lower compared to a case where the chip package 208 is overlapped on the circuit board 207. Therefore, the height of the measuring unit 213 can be reduced, and the physical quantity detection device 20 can be made thin, as shown in FIG. Fig. 3B, and the flow resistance in the main channel can be reduced. Incidentally, in the present embodiment, the case where the package front side portion 271c of the package body 271 is housed in the accommodation portion 207a of the circuit board 207 has been described as an example, but it may be configured such that the entire package body 271 is housed in the thickness direction. With such a configuration, it is possible to further promote the height reduction of the measuring unit 213 and reduce the thickness of the physical quantity detection device 20. <Anordnungsposition jedes Sensors>

[0064] As in Fig. As illustrated in Fig. 6A, the chip package 208, the pressure sensor 204, and the temperature and humidity sensor 206 are mounted on the circuit board 207. The chip package 208 is provided with a plurality of connection terminals 272 protruding from the proximal end portion 271a of the package body 271, and is fixed to the circuit board 207 because these connection terminals 272 are connected to the contact pads 264 of the circuit board 207 by soldering. The flow rate detection unit 205 and an LSI, which is an electronic component that drives the flow rate detection unit 205, are mounted in the chip package 208. The flow rate detection unit 205 is provided at a distal end portion 271b of the package body 271. The chip package 208 forms a support body on which a semiconductor element including the flow rate detection unit 205 and the LSI as a processing unit are mounted.

[0065] In the Fig. In the embodiment illustrated in FIGS. 6A to 6C, the chip package 208 is attached to the circuit board 207 such that the front side portion 271c of the package, which is one side in the thickness direction of the chip package 208, is located on the back side of the circuit board 207, that is, on the surface facing the cover 202. Therefore, the flow rate detection unit 205 can be arranged to face the cover 202, which is a conductive member, and static elimination can be performed on the measurement gas 2 flowing to the flow rate detection unit 205.

[0066] This static elimination prevents the dust contained in the measurement gas 2 from being charged, whereby the deposition of the dust on and around the flow rate detection unit 205 caused by the adsorption force of the charge can be suppressed and the high detection accuracy of the flow rate detection unit 205 can be maintained.

[0067] The pressure sensor 204 is mounted so that it is located closer to one side of the circuit board 207 than the chip package 208 in the longitudinal direction, while the temperature and humidity sensor 206 is mounted so that it is located closer to the other side of the circuit board 207 than the chip package 208 in the longitudinal direction. Then, the lead 203b of the intake air temperature sensor 203 is connected to the circuit board 207. The intake air temperature sensor 203 is mounted so that it is arranged at a position where the lead 203b is connected to a position closer to the other side of the circuit board 207 in the longitudinal direction than the temperature and humidity sensor 206, and the sensor body 203a protrudes from the circuit board 207 in the longitudinal direction to be exposed to the outside of the measuring unit 213.

[0068] On the measuring unit 213, (1) the pressure sensor 204, (2) the flow rate detection unit 205, (3) the temperature and humidity sensor 206, and (4) the intake air temperature sensor 203 are arranged in this order along the longitudinal direction from the proximal end portion side to the distal end portion side (in a direction of protrusion of the measuring unit 213). (1) The pressure sensor 204 detects the pressure of the measurement gas 2, and the flow rate detection unit 205 detects the flow rate of the measurement gas 2. The temperature and humidity sensor 206 detects the humidity of the measurement gas 2, and the intake air temperature sensor 203 detects the temperature of the measurement gas 2.

[0069] The physical quantity detection device 20 is arranged, for example, in an engine room of an automobile. The temperature in the engine room is 60°C to 100°C, while the temperature of the measurement gas 2 passing through the main duct 22 is 25°C on average. Therefore, heat in the engine room is transferred from the flange 211 side to the physical quantity detection device 20, and its temperature distribution is such that the temperature gradually decreases as it shifts from the flange 211 side toward the distal end portion of the measurement unit 213 side.

[0070] Therefore, in the measuring unit 213 of the present embodiment, (1) the pressure sensor 204, which has the smallest thermal effect, is arranged on the proximal end side, then (2) the flow rate detection unit 205, which has a small thermal effect on the high temperature side, is arranged closer to the distal end portion side of the measuring unit 213 than (1) the pressure sensor 204. Then, (3) the temperature and humidity sensor 206, which has a small thermal effect on the low temperature side, is arranged to be closer to the distal end portion side of the measuring unit 213 than (2) the flow rate detection unit 205 next, and (4) the intake air temperature sensor 203, which is most sensitive to heat, is arranged at the distal end portion of the measuring unit 213.

[0071] According to the present embodiment, the center of the circuit board 207 is cut out in the longitudinal direction to form the receiving portion 207a, and the proximal end portion 208a of the chip package 208 is accommodated therein. Then, the proximal end portion 208a of the chip package 208 is provided with the plurality of connection terminals 272 projecting in directions away from each other along the transverse direction of the package body 271. In the chip package 208, the distal end portion 271b including the flow rate detection unit 205 projects in a direction orthogonal to a channel direction of the sub-channel, and the plurality of connection terminals 272 are arranged to be divided into one side and the other side in the channel direction of the sub-channel.

[0072] On the circuit board 207, the plurality of contact pads 264 are provided so as to be divided into one side and the other side in the longitudinal direction of the circuit board 207, which is a portion where the contact pads 264 face each other with the receiving portion 207a therebetween, and the respective contact pads 264 are fixed by soldering. The chip package 208 has a stably supported structure in which both ends in the transverse direction of the proximal end portion 271a of the package body 271 are supported by the circuit board 207.

[0073] Additionally, in the present embodiment, the chip package 208 is arranged such that the longitudinal direction of the package body 271 is orthogonal to the extending direction of the second sub-channel groove 252, and the plurality of connection terminals 272, which are divided into two sides at predetermined intervals in the extending direction of the second sub-channel groove 252, are connected to the contact pads 264 of the printed circuit board 207. Therefore, the chip package 208 can be mounted at a correct position with respect to the printed circuit board 207 when mounted on the printed circuit board 207, forming a structure in which the second sub-channel groove 252 and the channel groove 273 of the package body 271 can be easily parallelized.

[0074] According to the present embodiment, the chip package 208 is arranged at an intermediate position between the pressure sensor 204 and the temperature and humidity sensor 206, exchanging signals between these sensors. Therefore, it is possible to shorten the signal transmission path between the chip package 208 and each sensor, improve the signal transmission speed, and suppress the generation of noise. <Konfiguration der Chipbaugruppe 208>

[0075] Fig. 7A is a front view of the chip assembly, Fig. 7B is a rear view of the chip assembly, Fig. 7C is a side view of the chip assembly, Fig. 7D is a bottom view of the chip assembly and Fig. Figure 7E is an isometric view of the chip assembly.

[0076] The chip package 208 is configured by attaching the LSI and the flow rate detection unit 205 to a lead frame and sealing the result with a thermosetting resin. The chip package 208 includes the package body 271 molded with resin into a substantially flat plate shape. The package body 271 has a rectangular shape and extends along the transverse direction of the measurement unit 213, such that the proximal end portion 271a on one side in the longitudinal direction of the package body 271 is disposed in the circuit chamber 235, and the distal end portion 271b on the other side in the longitudinal direction of the package body 271 is disposed in the second sub-channel groove 252.

[0077] The chip assembly 208 is electrically connected to the circuit board 207 and physically fixed to the circuit board 207 by soldering the plurality of connection terminals 272 provided at the proximal end portion 271a of the assembly body 271 to the contact pads 264 of the circuit board 207. The flow rate detection unit 205 is provided at the distal end portion 271b of the assembly body 271. The flow rate detection unit 205 is arranged to be exposed in the second sub-channel B. The flow rate detection unit 205 is provided in the channel groove 273 recessed on the surface of the assembly body 271. The channel groove 273 is formed over the entire width from an end portion on one side in the transverse direction to an end portion on the other side in the transverse direction of the assembly body 271 so as to extend along the second sub-channel B in the second sub-channel B.The flow rate detection unit 205 has a diaphragm structure. When the chip assembly 208 is resin-molded, the resin molding is performed by using an insert mold so that the resin does not flow into the surface of the flow rate detection unit 205.

[0078] Fig. Fig. 8 is a view illustrating a bent shape of the connection terminal according to the present embodiment, and Fig. 9 is a view illustrating a bent shape of a connection terminal according to a comparative example.

[0079] As in Fig. As illustrated in FIG. 8, the connection terminal 272 of the chip package 208 includes: a protruding portion 272a, which is a proximal end portion, a rising portion 272b, a falling portion 272c, and an end portion 272d, which is a distal end portion. The protruding portion 272a protrudes straight from the center of the package body 271 in the thickness direction along the transverse direction of the package body 271, and the rising portion 272b has a shape that rises from a distal end of the protruding portion 272a by being bent toward a package back side portion 271d, which is one side in the thickness direction of the package body 271.Then, the sloping portion 272c has a shape that is continuous with the rising portion 272b and slopes down so as to be bent toward the front side portion 271c of the assembly, which is the other side in the thickness direction of the assembly body 271 at a first bending height position, and the end portion 272d has a shape that is continuous with the sloping portion 272c and protrudes in a direction away from the assembly body 271 at a second bending height position.

[0080] The protruding portion 272a and the end portion 272d are located at different positions of the package body 271 in the thickness direction, and the end portion 272d is formed to be higher by δ than the protruding portion 272a on the package rear portion 271d side, which is one side in the thickness direction of the package body 271. Then, when the proximal end portion 271a of the package body 271 is accommodated in the receiving portion 207a of the circuit board 207, the protruding portion 272a, which is the base of the connection terminal 272, is arranged to abut against an upper surface of the circuit board 207, and the end portion 272d is arranged at a position facing the contact surface 264 on the upper surface of the circuit board 207 with the gap δ.That is, a state is formed in which the protruding portion 272a abuts against the top surface of the circuit board 207 and the end portion 272d floats from the circuit board 207.

[0081] The rising portion 272b and the falling portion 272c are formed to have moderate inclinations such that a falling angle θa2 of the falling portion 272c is set to be larger than a rising angle θa1 of the rising portion 272b, the falling portion 272c is inclined with respect to the circuit board 207 more than the rising portion 272b, and an inclination of the falling portion 272c is more moderate. In the present embodiment, a solder 281 is used as a connecting member to connect the end portion 272d and the contact surface 264 of the circuit board 207, and a so-called rear solder fillet 281a in which the solder 281 protrudes in a direction returning from the end portion 272d along the axial direction of the connection terminal 272 to the protruding portion 272a is formed between the connection terminal 272 and the circuit board 207.

[0082] A chip assembly 208' of the Fig. The comparative example illustrated in FIG. 9 is entirely arranged on the circuit board 207, and its connection terminals 272 include a protruding portion 272e, a sloping portion 272f, and an end portion 272g. The protruding portion 272e has a shape that protrudes from the center of the package body 271 in the thickness direction along the transverse direction of the package body 271, while the sloping portion 272f has a shape that slopes downwards so that it is bent from a distal end of the protruding portion 272e toward the rear portion 271d side of the package. Then, the end portion 272g has a shape that is bent at a lower end of the sloping portion 272f in a direction away from the package body 271 and protrudes along the transverse direction of the package body 271.The sloping portion 272f is formed to have an angle substantially perpendicular to the top surface of the circuit board 207.

[0083] When the chip assembly 208' of the comparative example is mounted on the circuit board 207, the total thickness hb is a value obtained by adding all of a thickness h1 of the back surface portion 271d of the assembly of the package body 271, a thickness h2 of the front surface portion 271c of the assembly, a gap h3 with respect to the circuit board 207, and a thickness h4 of the circuit board 207 (hb = h1 + h2 + h3 + h4). Because the chip assembly 208' of the comparative example is mounted on the circuit board 207, the overall mounting height becomes high. In addition, it is considered that the equivalent strain of the solder is mainly affected by a change in vertical strain in the Z direction, and a structure with a large mounting height is undesirable in terms of solder durability.

[0084] On the other hand, in the present embodiment, a total thickness ha when the chip package 208 of the present embodiment is mounted on the circuit board 207 is a value obtained by adding the thickness h2 of the package backside portion 271d and the thickness h1 of the circuit board 207 (ha = h2 + h1). Therefore, the present embodiment can achieve a height reduction compared to the comparative example. Incidentally, in the present embodiment, the thickness of the circuit board 207 can be made equal to the thickness h1 of the package backside portion 271d of the package body 271.

[0085] According to the present embodiment, the sloped portion 272c of the connection terminal 272 is moderately inclined with respect to the circuit board 207, and thus, a length L1 of the rear solder fillet 281a can be increased (L2 < L1) compared to the sloped portion 272f, which is substantially perpendicular to the circuit board 207 of the comparative example. Therefore, solder elongation can be reduced and the solder life can be extended. In addition, the sloped portion 272b of the connection terminal 272 has a smaller inclination angle than the sloped portion 272c, so that the total protrusion amount of the connection terminal 272 can be shortened and the chip package 208 can be downsized.

[0086] Incidentally, the case where the solder is used as the connecting member connecting between the contact surface 264 of the circuit board 207 and the connection terminal 272 has been described in the above embodiment, but the present invention is not limited thereto, and, for example, a welding alloy or a conductive adhesive may be used.

[0087] As described above, in the physical quantity detection device 20 of the present embodiment, the cover 202 attached to the housing 201 is configured using the conductive member, the circuit board 207 is fixed to the cover 202, and the chip package 208 is supported by the circuit board 207. The chip package 208 includes the flow rate detection unit 205 and is fixed to the circuit board 207 such that the flow rate detection unit 205 faces the cover 202. That is, the cover 202 is provided with a (conductive) potential, and the circuit board 207 or the chip package 208 for which static elimination is desired is arranged on the cover 202. Therefore, compared to a configuration in which, for example,An element for which static elimination is desired is stacked on a plate, a static elimination element is further disposed on the element, and the plate and the static elimination element are electrically connected by an additional element (a conductive path for static elimination), it is not necessary to provide an additional static elimination element. Consequently, the number of components can be reduced and assembly can be carried out easily, so that cost reduction can be achieved by reducing the assembly man-hours. In addition, in the present embodiment, the printed circuit board 207 is the member attached to the cover 202, and there is also an effect that an electrical path can be taken relatively easily.

[0088] Furthermore, according to the present embodiment, a part of the assembly body 271 in the thickness direction is housed in the receiving portion 207a of the circuit board 207. Consequently, compared with the comparative example with the configuration in which the proximal end portion 271a of the assembly body 271 is mounted on the circuit board 207, the distance between the flow rate detection unit 205 and the cover 202 can be shortened and the interval can be narrowed. Therefore, the measurement gas 2 can be brought into contact with various locations in the sub-channel 234 to promote static elimination before the measurement gas reaches and is supplied to the flow rate detection unit 205.In addition, it is possible to accelerate the flow of the measurement gas 2 passing through the channel groove 273 in which the flow rate detection unit 205 is provided in order to increase the responsiveness of the flow rate detection and reduce the noise.

[0089] In the physical quantity detection device 20 of the present embodiment, the chip assembly 208 includes the plurality of connection terminals 272, and is electrically connected and physically fixed by soldering the plurality of connection terminals 272 to the contact surfaces 264 of the circuit board 207. In the present embodiment, a part of the chip assembly 208 is housed in the receiving portion 207a, and the protruding portion 272a, which is the base of the connection terminal 272, is arranged on the circuit board 207, thereby positioning the chip assembly 208. In the comparative example, the end portion 272g provided at the folded distal end of the connection terminal 272 is arranged and soldered on the contact surface of the circuit board 207.Consequently, positioning the chip package 208 relative to the circuit board 207 is difficult, and there is a problem that the lead height varies greatly, affecting the positioning accuracy of the flow rate detection unit 205. According to the present embodiment, it is easier to position the chip package 208 relative to the circuit board 207 compared to the comparative example, and there is an advantage that the accuracy of the position where the flow rate detection unit 205 is arranged is high.

[0090] The Fig. 10A to 10C are views illustrating an embodiment of a support structure of a circuit board configured to set a potential of a cover, Fig. 10A is a line along the XA-XA to Fig. 5 taken cross-sectional view, Fig. 10B is an enlarged view of XB to Fig. 10A and Fig. 11 is a view illustrating the back of the cover.

[0091] The cover assembly is assembled by attaching the circuit board 207, on which the chip assembly 208 is mounted, to the back of the cover 202. The circuit board 207 is attached to the cover 202 with an adhesive. A plurality of projections 202a configured to support the circuit board 207 are provided in a portion of the cover 202 to which the circuit board 207 is attached. The number of projections 202a is preferably three or more, and is four in the present embodiment, as shown in Fig. 11 is illustrated.

[0092] The plurality of protrusions 202a have a convex spherical shape so that they can make point contact with a resist opening 207b of the circuit board 207. The shape of the protrusion 202a is not limited to the convex spherical shape; any shape that can make point contact, line contact, or surface contact with the resist opening 207b of the circuit board 207 can be used, for example, a conical shape or a convex shape with a triangular or quadrangular cross section.

[0093] The entire surface of the circuit board 207 is coated and covered with a resist F, but the resist F is not applied to a portion facing the projection 202a, and the resist opening 207b exposing the conductor of the circuit board 207 is provided, as shown in Fig. 10B. The circuit board 207 is mounted in a state where the protrusion 202a contacts the resist opening 207b of the circuit board 207, and the cover 202 and the circuit board 207 are electrically connected and fixed at a constant potential. According to the present embodiment, the circuit board 207 and the cover 202 can be electrically connected to each other without adding a special component, and the potential of the cover 202 can be fixed.

[0094] The circuit board 207 is precisely positioned relative to the cover 202 by being supported by the plurality of protrusions 202a. When the circuit board 207 is fixed to the cover 202 with an adhesive, variations in the mounting height of the circuit board 207 can be reduced. In addition, the inclination of the circuit board 207 relative to the cover 202 can be suppressed by being supported by the three or more protrusions 202a. Because the flow rate detection unit 205 is mounted on the circuit board 207, there is a possibility that the flow rate detection characteristics may be affected by the inclination of the circuit board 207.According to the present embodiment, the relative positions of the flow rate detection unit 205 of the chip package 208 mounted on the circuit board 207 and the cover 202 facing the flow rate detection unit 205 are accurately positioned by the three or more projections 202a, whereby the flow rate detection unit 205 can detect the flow rate with high accuracy.

[0095] The plurality of projections 202a are preferably provided at positions that can stably support the circuit board 207, and it is particularly preferable that at least one projection is provided in the vicinity of a bonding position, as shown in FIGS. Fig. 10A and Fig. 10B. For example, when the connector terminal 214 and the contact surface 265 of the circuit board 207 are electrically connected by the bonding wire 266, the bonding wire 266 is pressed against the contact surface 265 of the circuit board 207 by a bonding device (not illustrated), as shown in Fig. 3B. When the protrusion 202a is arranged in the vicinity of the contact surface 265, a pressing force can be received by the protrusion 202a and the processing accuracy of the bonding process can be increased.

[0096] The resist opening 207b differs from a through-hole 207c, which will be described later, and can be provided at a relatively free position on the back of the circuit board 207 regardless of the presence of a mounting component on the surface of the circuit board 207 corresponding to the position of the resist opening 207b. Therefore, the degree of freedom in designing the position where the protrusion 202a is provided is high, and implementation can be carried out easily. Therefore, for example, the resist opening 207b can be provided immediately below the contact surface 265, and the pressing force during the bonding process can be directly received by the protrusion 202a, thereby improving the processing accuracy of the bonding process.

[0097] The Fig. 12A and Fig. 12B are views illustrating another embodiment of the support structure of the printed circuit board, Fig. 12A is a view that Fig. 10A, and Fig. 12B is an enlarged view of XIIB to Fig. 12A.

[0098] A configuration in which the protrusion 202a is fitted into the through-hole 207c of the circuit board 207 is a feature of the present embodiment. The circuit board 207 is provided with the through-hole 207c that penetrates the circuit board 207 in the thickness direction and electrically connects the front and back surfaces of the circuit board 207. The through-hole 207c is provided at four locations in the present embodiment.

[0099] The through-hole 207c has an opening on the back of the circuit board 207 that is large enough to allow a portion of the protrusion 202a to enter. The protrusion 202a is provided at a position facing the through-hole 207c when the circuit board 207 is attached to the cover 202. The circuit board 207 is attached in a state where the protrusion 202a is fitted into the through-hole 207c of the circuit board 207, and the cover 202 and the circuit board 207 are electrically connected and fixed at a constant potential.

[0100] The circuit board 207 is precisely positioned relative to the cover 202 by fitting the protrusion 202a of the cover 202 into the through-hole 207c. Therefore, the relative positions of the flow rate detection unit 205 of the chip package 208 mounted on the circuit board 207 and the cover 202 facing the flow rate detection unit 205 are precisely positioned, and the flow rate detection unit 205 can detect the flow rate with high accuracy.

[0101] The position of the through-hole 207c is preferably provided at a position that can stably support the circuit board 207, and at least one through-hole is preferably provided in the vicinity of the bonding position. When the protrusion 202a is arranged in the vicinity of the contact surface 265, a pressing force can be received by the protrusion 202a, thereby increasing the processing accuracy of the bonding process.

[0102] The Fig. 13A and Fig. 13B are views illustrating still another embodiment of the support structure of the printed circuit board, Fig. 13A is a view that Fig. 10A, and Fig. 13B is an enlarged view of XIIIB after Fig. 13A.

[0103] A configuration in which the printed circuit board 207 is provided with a conductive convex portion 207d, and the convex portion 207d is brought into contact with the cover 202, is a feature of the present embodiment. A plurality of the convex portions 207d are provided on the back surface of the printed circuit board 207. The convex portion 207d is formed using a so-called land in which a solder is formed in an island shape with a predetermined height. Incidentally, the solder is used for the convex portion 207d in the present embodiment, but any conductive member, for example, a connection terminal such as a pad, may be used.The convex portions 207d are provided at positions that can stably support the circuit board 207 with respect to the cover 202, and are provided at four positions so that they are located at the corners of the circuit board 207 in the present embodiment.

[0104] The circuit board 207 is fixed to the cover 202 in a state where the convex portion 207d of the circuit board 207 is in contact with the back surface of the cover 202, and the cover 202 and the circuit board 207 are electrically connected and fixed at a constant potential.

[0105] The circuit board 207 is precisely positioned with respect to the cover 202 because the convex portions 207d of the circuit board 207 are brought into contact with the back of the cover 202. Therefore, the relative positions of the flow rate detection unit 205 of the chip package 208 mounted on the circuit board 207 and the cover 202 facing the flow rate detection unit 205 are precisely positioned, and the flow rate detection unit 205 can detect the flow rate with high accuracy.

[0106] The position of the convex portion 207d is preferably provided at a position that can stably support the circuit board 207 with respect to the cover 202, and at least one convex portion is preferably provided in the vicinity of the bonding position. When the convex portion 207d is provided in the vicinity of the contact surface 265, a pressing force can be transmitted to the cover 202 via the convex portion 207d and received by the cover 202, thus improving the processing accuracy of the bonding process.

[0107] Fig. Fig. 14 is a view for describing another embodiment of the printed circuit board and is the Fig. 5 corresponding view.

[0108] A configuration in which the circuit board 207 and the cover 202 are electrically connected by a bonding wire 267 is a feature of the present embodiment.

[0109] The bonding wire 267 has one end bonded to the contact surface 265 of the circuit board 207 and the other end bonded to the back surface of the cover 202. For example, the bonding work can be performed simultaneously when the plurality of contact surfaces 265 of the circuit board 207 and the connector terminals 214 of the housing 201 are bonded with bonding wires. According to the present embodiment, a potential of the cover 202 can be fixed regardless of a method for attaching the circuit board 207 to the cover 202. The present embodiment can be implemented in addition to the respective embodiments described above, or can be implemented independently without accompanying the respective embodiments described above.

[0110] According to the present embodiment, the cover 202 and the contact pad 265 of the circuit board 207 are electrically connected by the bonding wire 267, and the cover 202 is fixed at a constant potential. Because the present embodiment uses a connection instead of the contact as in the respective embodiments described above, the cover 202 can be reliably electrically connected to the circuit board 207, and the cover 202 can be reliably fixed at the constant potential.

[0111] Fig. Fig. 15 is a view for describing still another embodiment of the printed circuit board and is the Fig. 5 corresponding view.

[0112] It is a feature of the present embodiment that the flow rate detection unit 205 is directly mounted on a circuit board 207'. Although the case where the chip package 208 with the flow rate detection unit 205 is mounted on the circuit board 207 has been described as an example in the above-described respective embodiments, the chip package 208 is not an essential element; it suffices that the flow rate detection unit 205 is mounted on the circuit board 207' facing the cover 202.

[0113] The circuit board 207' has a substantially T-shape extending in a longitudinal direction and protruding in a transverse direction from a central position in the longitudinal direction. On the circuit board 207', a longitudinally extending body portion 291 is housed in the circuit chamber 235 of the housing 201, and a portion 292 protruding from the body portion 291 is disposed in the second sub-channel B.

[0114] The flow rate detection unit 205 is provided on the protruding portion 292 of the circuit board 207' on a back side of the circuit board 207' and is arranged to oppose the cover 202 at a predetermined interval to allow the passage of the measurement gas 2 that has flowed into the second sub-channel B.

[0115] According to the present embodiment, because the flow rate detection unit 205 is directly provided on the circuit board 207', the relative positions of the flow rate detection unit 205 and the cover 202 facing the flow rate detection unit 205 are accurately positioned, and the flow rate detection unit 205 can detect the flow rate with high accuracy.

[0116] Fig. Fig. 16 is a view for describing another embodiment of the cover assembly and is the Fig. 5 corresponding view.

[0117] It is a feature of the present embodiment that a mounting plate 293 on which the flow rate detection unit 205 is mounted is used instead of the chip package 208. Although the case where the chip package 208 with the flow rate detection unit 205 is mounted on the circuit board 207 has been described as an example in the above-described respective embodiments, the chip package 208 is not an essential element; it suffices that the flow rate detection unit 205 is mounted on the circuit board 207 facing the cover 202.

[0118] The mounting plate 293 has a proximal end portion accommodated in the receiving portion 207a of the circuit board 207 and a distal end portion projecting to be disposed in the second sub-channel B. The flow rate detection unit 205 is provided on a back side of the mounting plate 293 and is arranged to oppose the cover 202 at a predetermined interval to allow the passage of the measurement gas 2 that has flowed into the second sub-channel B. According to the present embodiment, the yield is higher than that of the above-described substantially T-shaped circuit board 207', and thus the number of circuit boards 207 can be increased.

[0119] According to the present embodiment, the stress acting on a measuring element of the flow rate detection unit 205 is reduced compared to a case where components such as the flow rate detection unit 205 are directly mounted on the circuit board 207, so that the durability and reliability of the physical quantity detection device 20 can be improved. Incidentally, mounting the components on the circuit board 207 includes, for example, fixing the components to the circuit board 207 and electrically connecting the components to a wiring of the circuit board 207. Examples of the mounting board 293 include a metal lead frame, an LTCC board, a circuit board on which electrical wiring can be formed, and a metal plate.

[0120] As above, the embodiments of the present invention have been described in detail, but the present invention is not limited to the above-described embodiments, and various design modifications may be made without departing from the spirit of the present invention set forth in the claims. For example, the above-described embodiments have been described in detail in order to describe the present invention in an easy-to-understand manner, and they are not necessarily limited to one including the entire configuration described above. In addition, the configurations of another embodiment may be substituted for some configurations of a certain embodiment, and further, a configuration of another embodiment may be added to a configuration of a certain embodiment.Furthermore, with respect to some configurations of each embodiment, addition, deletion, or replacement of other configurations may be performed. List of reference symbols 1 internal combustion engine control system 2 Sample gas 20 Detection device for physical quantities 22 Main channel 201 housing 202 Cover 203 Intake air temperature sensor 204 pressure sensor 205 Flow rate detection unit 206 Temperature and humidity sensor 207 circuit board 208 chip assembly 211 Flange 212 connectors 213 measuring unit 214 connector connection 221 Front 222 back 223 side area on one side 224 side surface on the other side 226 subpage 231 Sub-channel inlet 232 first outlet 233 second outlet 234 subchannel 235 Circuit Chamber 237 Rib (bottom of the circuit chamber) 240 ventilation duct 241 mounting hole 242 through hole 243 first rib 244 second rib 245 third rib 246 fourth rib 247 external connection 248 Correction connection 249 Ventilation hole (ventilation duct outlet) 250 sub-channel groove 251 first sub-channel groove 252 second sub-channel groove 253 lead 254 Ventilation hole (ventilation duct inlet) 255 R3 intake 256 ventilation groove 263 Contact surface (for intake air temperature sensor) 264 contact area (for chip assembly connection) 265 contact area (for wire bonding) 271 assembly body 272 connection port 273 channel groove

Claims

[1] Physical quantity detection device (20) comprising: a semiconductor element having a flow rate detection unit (205); a circuit board (207) supporting the semiconductor element; and a conductive base element that secures the circuit board (207), wherein the semiconductor element is mounted on the circuit board (207) such that the flow rate detection unit (205) faces the base element, where either the printed circuit board (207) is provided with a resist opening (207b) in which a conductor is exposed, and a projection (202a) provided on the base member is in contact with the conductor exposed from the resist opening (207b); or the circuit board (207) is provided with a through hole (207c) penetrating the circuit board (207), and a projection (253) provided on the base member and the through hole (207c) are fixed to each other; or the printed circuit board (207) is provided with a soldering pad, and the solder pad and the base element come into contact with each other. [2] A physical quantity detection device (20) according to claim 1, wherein the base element is electrically connected to the circuit board (207) and is fixed at a constant potential. [3] The physical quantity detecting device (20) according to claim 1, wherein the circuit board (207) is a glass epoxy board. [4] A physical quantity detecting device (20) according to claim 1, wherein the base member is made of an aluminum alloy. [5] The physical quantity detecting device (20) according to claim 1, further comprising a sub-channel for supplying a measurement gas to the flow rate detecting unit (205), wherein the base member forms a part of the sub-channel. [6] The physical quantity detecting device (20) according to claim 5, further comprising a support body that supports the semiconductor element, wherein in the support body, a portion in a thickness direction of a proximal end portion (208a) of the support body is accommodated in a receiving portion (207a) of the circuit board (207) so that the proximal end portion (208a) of the support is supported by the circuit board (207), and a distal end portion (271b) of the support body that includes the flow rate detecting unit (205) protrudes from the circuit board (207) and is arranged in the sub-channel.

Images