DETECTION DEVICE FOR PHYSICAL QUANTITIES

Abstract

A physical quantity detection device (20) comprising: a support body on which a flow rate detection unit and a processing unit are mounted; and a printed circuit board (207) with a receiving section (207a) in which a section of the support body is housed, wherein at least one section in a thickness direction of the support body is housed in the receiving section (207a) and a section containing the flow rate detection unit projects from the receiving section (207a), characterized in that the receiving section (207a) is formed by cutting out a part of the printed circuit board (207).

Description

Technical FieldThe present invention relates to a physical quantity detection device that detects a physical quantity of, for example, intake air of an internal combustion engine.Background ArtThere is an air flow rate measurement device as a device that measures a physical quantity of a measurement gas flowing through a main passage. In the air flow rate measurement device, a circuit board on which mounting components such as a pressure sensor, a humidity sensor, an intake air temperature sensor, a storage LSI, and a chip capacitor are mounted, and a flow rate sensor-incorporated chip package are arranged.For example, PTL 1 discloses a configuration in which a memory LSI package is stacked in two layers in a recessed portion of a wiring board and is electrically connected to the board. PTL 2 shows a physical quantity detection device including: a chip package in which a flow sensor and an electronic component are sealed using resin; and a circuit board on which the chip package is mounted. The chip package is fixed to a circuit board surface of the circuit board, a part of the chip package protrudes laterally from an end of the circuit board, and the circuit board includes a flat edge portion wider than a width of the chip package, the edge portion being provided at a position on a circuit board surface and at a position biased in a direction opposite to a direction protruding from the chip package.List of ReferencesPatent LiteraturePTL 1: JP H8-316606 APTL 2: DE 11 2018 003 485 T5SUMMARY OF THE INVENTIONTechnical ProblemIn the above-described conventional device in PTL 1, the memory LSI package is mounted in the recessed portion of the wiring board in two layers to enable mounting of more memories than the number that can be disposed within a limited mounting range, and does not contribute to reduction in the size of a sensor device. A sensor that measures a flow rate of intake air sucked into an internal combustion engine requires a downsized structure to reduce a pressure loss. In addition, the reliability of a connection portion of the assembly depending on the mounting height is largely affected by vertical elongation in the Z direction, so that a structure having a large mounting height is not desired.The present invention has been made in view of the above points, and its object is to provide a compact physical quantity detection device that can reduce a mounting height of a chip package and improve the reliability of a connection portion of the chip package.Solution of the ProblemTo solve the above problem, the features of the independent claims are proposed. The dependent claims relate to preferred embodiments.Advantageous Effects of the InventionAccording to the present invention, the mounting height of the chip package can be suppressed by accommodating a part of the chip package in the accommodating portion of the board. Therefore, the physical quantity detection device itself can be downsized, providing the physical quantity detection device that can improve a terminal structure contributing to the durability of a connection portion even when the height of assembly mounting is reduced.Another feature relating 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 DrawingsFIG. 1 is a system diagram illustrating an embodiment in which a physical quantity detection device according to the present invention is used in an engine control system. FIG. 2A is a front view of the physical quantity detection device. FIG. 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 left side view 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 cross-sectional view taken along the line IIIA-IIIA of FIG. 2D. FIG. 3B is a cross-sectional view taken along the line IIIB-IIIB of FIG. 2A. FIG. 3C is a cross-sectional view taken along the line IIIC-IIIC of FIG. 2A. FIG. 3D is a front view of a housing from which only one cover has been removed. FIG. 4A is a front view of the housing from which a cover assembly has been removed. FIG. 4B is a cross-sectional view taken along the line IVB-IVB of FIG. 4A. FIG. 5A is a view illustrating a configuration of a cover assembly. FIG. 5B is a cross-sectional view taken along the line VB-VB of FIG. 5A. FIG. 6A is a front view of a circuit board on which a chip package and circuit components are mounted. FIG. 6B is a cross-sectional view taken along the line VIB-VIB of FIG. 6A. FIG. 6C is a cross-sectional view taken along the line VIC-VIC of FIG. 6A. FIG. 6D is a view illustrating another configuration example of the circuit board. FIG. 7A is a view illustrating a configuration example of a circuit board. FIG. 7B is a view illustrating another configuration example of the circuit board. FIG. 7C is a view illustrating still another configuration example of the circuit board. FIG. 8A is a front view of the chip package. FIG. 8B is a rear view of the chip package. FIG. 8C is a side view of the chip package. FIG. 8D is a bottom view of the chip package. FIG. 8E is an isometric view of the chip package. FIG. 9 is a view illustrating a bent shape of a connection terminal according to the present embodiment. FIG. 10 is a view illustrating a bent shape of a connection terminal according to a comparative example. FIG. 11 is a view illustrating the relationship between the bending height of a connection terminal and an equivalent strain. FIG. 12 is a view illustrating a configuration in which a sensor is directly attached to a circuit board.DESCRIPTION OF THE EMBODIMENTSA manner of carrying out the invention (hereinafter, an embodiment) to be described later solves various problems of which solution is desired as an actual product, and particularly solves various types of problems desired for use as a detection device that detects a physical amount of intake air of a vehicle and achieves various effects. One of various problems to be solved by the following embodiment corresponds to the contents described in the Technical Problem section described above. In addition, one of various effects to be obtained by the following embodiment corresponds to the effect described in the above-described Advantageous Effects of the Invention. 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 except for the content in the Technical Problem section and the content in the Advantageous Effects section of the invention will be also described in the following embodiment.In the following embodiment, the same reference numerals represent the same configurations even among different drawings and achieve the same effects. There is also a case where only a reference sign of a configuration that has already been described in a drawing is given, and description thereof is omitted.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. The intake air is sucked from an air cleaner 21 as a measurement gas 2 based on an operation of an internal combustion engine 10 including an engine cylinder 11 and an engine piston 12, and introduced into a combustion chamber of the engine cylinder 11 via, for example, an intake body 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. Fuel is supplied through a fuel injection valve 14 based on the detected physical quantity and is supplied to the combustion chamber as an air-fuel mixture with the measurement gas 2 in the state. Incidentally, in the present embodiment, the fuel injection valve 14 is provided at an intake passage of the internal combustion engine, and the fuel injected into the intake passage forms the air-fuel mixture together with the measurement gas 2. The air-fuel mixture is introduced into the combustion chamber via an intake valve 15 and burned to generate mechanical energy.The fuel and the air introduced into the combustion chamber form a mixed state of the fuel and the air, and are explosively burned by the spark ignition of a spark plug 13, thereby generating the mechanical energy. After burning, the gas is sent from an exhaust valve 16 into an exhaust pipe, and is discharged as an exhaust gas 3 from the exhaust pipe to the outside of an automobile. A flow rate of the measurement gas 2 as the intake air supplied to the combustion chamber is controlled by a throttle valve 25 whose opening degree is changed based on an operation of an accelerator pedal. A supply amount of the fuel is controlled based on the flow rate of the intake air supplied to the combustion chamber, and 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 the intake air supplied to the combustion chamber.< On Control of Engine Control System>The physical quantity, such as the flow rate, temperature, humidity, and pressure, of the measurement gas 2, which is the intake air taken out from the air cleaner 21 and flowing in the main passage 22, is detected by the physical quantity detection device 20, and an electric signal indicating 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 that measures the opening degree of the throttle 25 is input to the control device 4. Further, 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 rotation 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.The control device 4 calculates a fuel injection amount and an ignition timing based on the physical quantity of the intake air as the output of the physical quantity detection device 20 and the rotation speed of the internal combustion engine measured based on the output of the rotation angle sensor 17. Based on these calculation results, the amount of fuel 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 the ignition timing are further finely controlled based on a state of change in temperature or a throttle angle detected by the physical quantity detecting device 20, a state of change in engine speed, and a state of 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 idle running state of the internal combustion engine and controls the rotation speed of the internal combustion engine in the idle running state.Both the supply amount of the fuel and the ignition timing, which are essential control variables of the internal combustion engine, are calculated using the physical quantity detection device 20 output as the main parameters. Accordingly, the improvement of the detection accuracy of the physical quantity detection device 20, the suppression of a change with time, and the improvement of the reliability are important in terms of improving the control accuracy of a vehicle and securing the reliability.Particularly, recently, a demand for fuel saving of vehicles has been extremely increased, and further, the demand for purification of an exhaust gas has been extremely increased. In order 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 maintain high reliability.A vehicle equipped with the physical quantity detection device 20 is used in an environment in which a change in temperature or humidity is large. It is desirable that the physical quantity detection device 20 is configured in consideration of the response to such a change in temperature or humidity in the use environment and the response to dust, contaminants, and the like.In addition, the physical quantity detection device 20 is attached to the intake pipe affected by the heat generated from the internal combustion engine. Consequently, the heat generated from the internal combustion engine is transmitted to the physical quantity detection device 20 via the inlet pipe serving as the main passage 22. The physical quantity detection device 20 detects the flow rate of the measurement gas 2 by performing the heat transfer with the measurement gas 2, and thus it is important to suppress the influence of the heat from the outside as much as possible.The physical quantity detection device 20 installed in the automobile not only solves the problem described in the Technical Problem section and achieves not only the effects described in the Advantageous Effects section of the invention as described later, but also solves various problems and also achieves various effects required in sufficiently considering the various problems described above as the product as described later. 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.< Structure of Physical Quantity Detection Device>FIGS. 2A to 2F are views illustrating an appearance of the physical quantity detection device. Incidentally, in the following description, it is assumed that the measurement gas flows along the central axis of the main passage.The physical quantity detection device 20 is used by being inserted into the main passage 22 through a fixing hole provided in a passage wall of the main passage 22. The physical quantity detection device 20 includes a housing 201 and a cover 202 fixed to the housing 201. The housing 201 is configured by injection molding a resin material, and the cover 202 is formed using a plate-shaped member made of a conductive material such as aluminum alloy. The cover 202 is formed in a thin plate shape and has a wide flat cooling surface.The housing 201 includes: a flange 211 configured to fix the physical quantity detection device 20 to the inlet body as the main passage 22; a connector 212 protruding from the flange 211 and exposed to the outside from the inlet body to realize electrical connection with an external device; and a measurement unit 213 extending to protrude from the flange 211 toward the center of the main passage 22.The measurement unit 213 has a thin and long shape extending from the flange 211 toward the center of the main duct 22, and has a wide front side 221 and a wide rear side 222, and a pair of narrow side surfaces 223 and 224. The measurement unit 213 protrudes from an inner wall of the main duct 22 toward a duct center of the main duct 22 in a state where the physical quantity detection device 20 is fixed to the main duct 22. Then, the front surface 221 and the back 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 measurement unit 213, the side surface 223 on one side of the measurement unit 213 in the transverse direction is disposed to face the upstream side of the main duct 22, while the side surface 224 on the other side of the measurement unit 213 in the transverse direction is disposed to face the downstream side of the main duct 22. In the state where the physical quantity detection device 20 is attached to the main duct 22, a distal end portion of the measurement unit 213 serves as a lower surface 226.Because a sub-channel inlet 231 is provided at the distal end portion of the measurement unit 213, which extends 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 instead of 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 duct 22, and suppress a decrease in measurement accuracy caused by the influence of heat or the like.The vicinity of the inner wall surface of the main passage 22 is in the state that it is easily affected by the temperature of the main passage 22, so that the temperature of the measurement gas 2 is different from the original temperature of the gas that is different from an average state of the main gas in the main passage 22. In particular, when the main passage 22 is the intake body of the engine, it is often maintained at a high temperature due to the influence of the heat from the engine. Consequently, the [die] gas [temperature] in the vicinity of the inner wall surface of the main channel 22 is often higher than the original temperature of the main channel 22, causing a decrease in measurement accuracy. In addition, in the vicinity of the inner wall surface of the main passage 22, the fluid resistance is large, and the flow speed becomes smaller than an average flow speed of the main passage 22. Consequently, if the gas in the vicinity of the inner wall surface of the main passage 22 is taken into the sub-passage as the measurement gas 2, there is a possibility that the decrease in the flow velocity with respect to the average flow velocity of the main passage 22 results in a measurement error.Because the physical quantity detection device 20 is provided with the sub-passage inlet 231 at the distal end portion of the thin and long measurement unit 213 extending from the flange 211 toward the center of the main passage 22, it is possible to reduce the measurement error with respect to the decrease in the 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 measurement 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 measurement unit 213 in the physical quantity detection device 20, and thus the measurement error can be further reduced.The physical quantity detection device 20 has a shape in which the measurement unit 213 extends so as to be long along the axis from an outer wall of the main duct 22 toward the center, and the widths of the side surfaces 223 and 224 have a narrow shape, as illustrated in FIGS. 2B and 2D. As a result, the physical quantity detection device 20 can suppress the fluid resistance of the measurement gas 2 to a small value.< Of Temperature Detection Unit>In the physical quantity detection device 20, an intake air temperature sensor 203, which is a temperature detection unit, is provided in the measurement unit 213, as illustrated in FIG. 2B. The intake air temperature sensor 203 is disposed in the middle of a duct of a temperature sensing duct having one end 238 open near the sub-duct inlet 231 and another end 239 open to the rear 222 of the sensing unit 213. The temperature measurement passage is formed by the housing 201 and the cover 202.As illustrated in FIG. 6A, the intake air temperature sensor 203 is formed of an axial pipe component including a columnar sensor body 203 aand a pair of pipes 203 bprotruding from both axial end portions of the sensor body 203 ain 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 pipes 203 b, and the sensor body 203 ais disposed so as to be orthogonal to the flow direction of the measurement gas 2 in the temperature measurement passage.Because the intake air temperature sensor 203 is disposed in the temperature measurement passage formed by the housing 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 the transportation or attachment work of the physical quantity detection device 20.According to the physical quantity detection device 20 of the present embodiment, the intake air temperature sensor 203 is disposed 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.< Of Flange>The measurement unit 213 of the physical quantity detection device 20 is inserted inside through the fixing hole provided in the main passage 22, the flange 211 of the physical quantity detection device 20 abuts on the main passage 22, and is fixed to the main passage 22 with a screw. The flange 211 has a substantially rectangular shape having a predetermined plate thickness in a plan view, and a pair of fixing holes 241 are provided at diagonal corners, as illustrated in FIGS. 2E and 2F. The fixing hole 241 has a through hole 242 penetrating the flange 211. The flange 211 is fixed to the main channel 22 by inserting a fixing bolt (not shown) into the through hole 242 of the fixing hole 241 and screwing the bolt into a bolt hole of the main channel 22.As illustrated in FIG. 2E, a plurality of ribs are provided on the upper surface of the flange 211. The ribs include: a first rib 243 linearly connecting the attachment hole 241 and the connector 212; a second rib 244 having a tapered cross section surrounding the periphery of the through hole 242 of the attachment 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.The first rib 243 is linearly provided between the fastening hole 241 on which a screw fastening force acts on the main channel 22 and the connector 212 having a relatively high rigidity due to its three-dimensional shape, and thus a flange reinforcing effect is high. Therefore, as compared with that having no 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 constituting the flange 211 during molding of the housing 201.As illustrated in FIG. 2E, the connector 212 is provided with four outer terminals 247 and the correction terminals 248 therein. The external terminals 247 serve as a terminal to output 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 to supply DC power for the operation of the physical quantity detection device 20.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.Therefore, the correction terminal 248 has a shape different from that of the outer terminal 247, so that the correction terminal 248 does not interfere when the outer terminal 247 is connected to another outer device. In the present embodiment, the correction terminal 248 has a shorter shape than the outer terminal 247 so as not to interfere with connection even when a connection terminal to the outer device connected to the outer terminal 247 is inserted into the connector 212.< Of Housing>FIG. 3A is a cross-sectional view taken along the line IIIA-IIIA of FIG. 2D, FIG. 3B is a cross-sectional view taken along the line IIIB-IIIB of FIG. 2A, FIG. 3C is a cross-sectional view taken along the line IIIC-IIIC of FIG. 2A, and FIG. 3D is a front view of a case from which only the cover has been removed.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-passage 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 a lateral direction side (on the side surface 223 side) of the main passage 22 that is on the upstream side in the flow direction of the measurement gas 2. Then, the sub-passage groove 250 is provided over a region located closer to the distal end side (the lower side 226 side) than the circuit chamber 235 in the longitudinal direction of the measurement unit 213, and a region located closer to the other side (the side surface 224 side) than the circuit chamber 235 in the flow direction of the measurement gas 2 on the downstream side in the lateral direction of the main passage 22.The sub-channel groove 250 forms a sub-channel 234 in cooperation with the cover 202. The sub-channel 234 is provided to extend along a direction of protrusion (longitudinal direction) of the measurement unit. The sub-passage groove 250 forming the sub-passage 234 includes a first sub-passage groove 251 and a second sub-passage groove 252 branching at the center of the first sub-passage groove 251. The first sub-passage groove 251 is formed to extend along the lateral direction of the measurement unit 213 between the sub-passage inlet 231 open on the side surface 223 on one side of the measurement unit 213 and the first outlet 232 open on the side surface 224 on the other side of the measurement unit 213. The first sub-passage groove 251 forms a first sub-passage that receives the measurement gas 2 flowing in the main passage 22 from the sub-passage inlet 231 and returns the received measurement gas 2 from the first outlet 232 to the main passage 22. The first sub-passage extends from the sub-passage inlet 231 along the flow direction of the measurement gas 2 in the main passage 22, and is connected to the first outlet 232.The second sub-passage groove 252 branches at an intermediate position of the first sub-passage groove 251, is bent toward a proximal end portion (flange side) side of the measurement unit 213, and extends along the longitudinal direction of the measurement unit 213. Then, the second sub-channel groove 252 at the proximal end portion of the measurement unit 213 is bent toward the other side (side surface 224 side) in the lateral direction of the measurement unit 213, making a U-turn toward the distal end portion of the measurement unit 213, and again extending along the longitudinal direction of the measurement unit 213. Then, the second sub-passage groove 252 is bent toward the other side in the lateral direction of the measurement unit 213 in front of the first outlet 232, and is provided so as to be continuous with the second outlet 233 open to the side surface 224 on the other side of the measurement unit 213. The second outlet 233 is disposed to face the downstream side in the flow direction of the measurement gas 2 in the main passage 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 more proximal to the proximal end portion side in the longitudinal direction of the measurement unit 213 than the first outlet 232.The second sub-passage groove 252 forms a second sub-passage that allows the measurement gas 2 to pass therethrough after being branched from and flowed through the first sub-passage to return the measurement gas 2 from the second outlet 233 to the main passage 22. The second sub-channel has a path that reciprocates along the longitudinal direction of the measurement unit 213.That is, the second sub-channel has a path branching in the middle of the first sub-channel, extending toward the proximal end portion side of the measurement unit 213, folded back at the proximal end portion side of the measurement unit 213 to extend toward the distal end portion side of the measurement unit 213, and leading to the second outlet 233 disposed on the downstream side of the sub-channel inlet 231 in the main channel 22 in the flow direction of the measurement gas 2 to face the downstream side in the flow direction of the measurement gas 2. A flow rate sensor 205 is disposed at an intermediate position of the second sub-passage groove 252. The second sub-channel groove 252 may ensure a longer channel length of the second sub-channel, and may reduce the influence on the flow rate sensor 205 when pulsation occurs in the main channel.According to the above configuration, the sub-channel 234 may be formed along an extending direction of the measurement unit 213, and it may be sufficiently ensured that the length of the sub-channel 234 is long. As a result, the physical quantity detection device 20 can include the sub-channel 234 having 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 the small value.The first sub-passage groove 251 is provided to extend from the sub-passage inlet 231 to the first outlet 232 along the transverse direction of the measurement unit 213, and thus a foreign substance such as dust that has entered the first sub-passage from the sub-passage inlet 231 can be directly discharged from the first outlet 232. Therefore, it is possible to prevent intrusion of foreign matter into the second sub-channel and to prevent the flow rate sensor 205 from being influenced in the second sub-channel.The sub-passage inlet 231 and the first outlet 232 of the first sub-passage groove 251 have a larger opening area at the sub-passage inlet 231 than at the first outlet 232. Because the opening area of the sub-passage inlet 231 is larger than that of the first outlet 232, the measurement gas 2 that has flowed into the first sub-passage can be reliably guided to the second sub-passage branching at the center of the first sub-passage.At the sub-passage inlet 231 of the first sub-passage 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 to cause each part to have a smaller opening area than the first outlet 232 and the second outlet 233. The protrusion 253 controls a size of the foreign substance that can enter the first sub-channel from the sub-channel inlet 231 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 substance.<Structure of Single Case>FIG. 4A is a front view of the housing from which a cover assembly has been removed, and FIG. 4B is a cross-sectional view taken along line IVB-IVB of FIG. 4A.As illustrated in FIG. 4A, the housing 201 is provided with the ribs 237 on a lower surface of the circuit chamber 235. The ribs 237 include a plurality of vertical ribs extending along the longitudinal direction of the measurement unit 213 and a plurality of horizontal ribs extending along the transverse direction of the measurement unit 213, being provided in a lattice pattern.Because the measurement unit 213 is provided with the ribs 237, the housing 201 can obtain high rigidity without increasing the thickness. The thickness of the housing 201 largely differs between the flange 211 and the measurement unit 213, a difference in heat shrinkage after injection molding is large, and the measurement unit 213, which is thinner than the flange 211, is easily deformed. Therefore, by providing the lattice-shaped ribs spreading in a planar shape on the bottom surface of the circuit chamber 235, it is possible to suppress the deformation of the measurement unit 213 at the time of heat shrinkage.The housing 201 is provided with the ribs 237 not on an outer wall of the measurement unit 213 but on the bottom surface of the circuit chamber 235. If provided on the outer wall of the measurement unit 213, there is a possibility that the ribs 237 are influenced by the flow of the measurement gas 2 passing through the main passage 22. In addition, when the depth of the circuit chamber 235 is set on the assumption that the single-side mounting circuit board 207 is accommodated, if the specifications are changed, the depth of the circuit chamber 235 needs to be increased to accommodate the double-side mounting circuit board 207. However, if the ribs are provided on the outer wall of the measurement unit 213, the ribs protrude by increasing the depth of the circuit chamber 235, so that the thickness of the measurement unit 213 increases. Therefore, the thickness of the measurement unit 213 is different between the one-side mounting and the double-side mounting, which is likely to affect the detection accuracy.On the other hand, in the present embodiment, the ribs 237 are provided at the bottom of the circuit chamber 235, and thus it is possible to prevent the influence on the flow of the measurement gas 2 passing through the main passage 22 and to allow the measurement gas 2 to flow smoothly. Then, the depth of the bottom surface of the circuit chamber 235 can be changed simply by changing the height of the rib 237 in the circuit chamber 235, and it is unnecessary to change the thickness of the measurement unit regardless of whether the circuit board 207 corresponds to the one-side mounting or the double-side mounting.< Of Cover Assembly>FIG. 5A is a view illustrating a configuration of the cover assembly, and FIG. 5B is a cross-sectional view taken along the line VB-VB of FIG. 5A.The cover assembly is formed by the cover 202 and the circuit board 207 on which a chip package 208 is mounted. The cover 202 is formed using a conductive material of metal, for example, an aluminum alloy and a stainless alloy. The cover 202 is a flat plate member having a size covering the front side of the measurement unit 213, and is fixed to the measurement unit 213 with an adhesive. In addition, the cover 202 covers the circuit chamber 235 of the measurement unit 213, and forms a sub-passage in cooperation with the sub-passage groove 250 of the measurement unit 213. The cover 202 is electrically connected to the ground by interposing a conductive intermediate member between the cover 202 and a predetermined connector terminal 214, and has a function of [electro]static elimination.The circuit board 207 on which the chip package 208 is mounted is fixed to a back side of the cover 202. The circuit board 207 is made of, for example, a printed circuit board and has a rectangular shape extending along the longitudinal direction of the measurement unit 213. The chip package 208 is fixed to the circuit board 207 at the central position in the longitudinal direction of the circuit board 207 in a state of protruding laterally from an end portion along the lateral direction of the circuit board 207. A package body 271 of the chip package 208 includes: a proximal end portion 271 aof which at least a portion in the thickness direction is accommodated in the accommodation portion 207 aof the circuit board 207; and a distal end portion 271 bprotruding toward the lateral side from an end portion of the circuit board 207 along the lateral direction of the circuit board 207.The cover assembly may receive the circuit board 207 in the circuit chamber 235 by attaching the cover 202 to the housing 201 and allow the chip package 208 to extend between the sub-channel 234 and the circuit chamber 235 such that the distal end portion 271 bof the package body 271 may be disposed in the sub-channel 234. The flow rate sensor 205 is provided at the distal end portion 271 bof the assembly body 271 and is disposed in the second sub-passage groove 252.<Seal Structure in Circuit Chamber>In the circuit chamber 235, a hatched portion in FIG. 3D is bonded to the cover 202 with an adhesive. As illustrated in FIG. 3A, the front side of the circuit board 207 in the circuit chamber 235 is hermetically divided into the three spaces R 1, R 2, and R 3. Specifically, the first space R 1 to which a connector terminal 214 integrally molded with the housing 201 and a connection terminal of the circuit board 207 are connected, and the second space R 2 for accommodating a pressure sensor 204 and a part of the chip package 208, and a third space R 3 in which a temperature and humidity sensor 206 is accommodated and the duct 203 bof the intake air temperature sensor 203 is inserted are formed.The first space R 1 is sealed by the cover 202 on the front side and is open through an opening 227 of the housing 201 on the rear side, as illustrated in FIG. 2C. However, the opening 227 is filled with a resin material after the connector terminal 214 and the connection terminal of the circuit board 207 are electrically connected by wire bonding. That is, the first space R 1 is a hermetically sealed space isolated from the outside of the measurement unit 213 by sealing the front side and the back side. Therefore, a connection portion between the connector terminal 214 and the connection terminal can be prevented from coming into contact with and corrosive to a gas contained in the measurement gas 2.The second space R 2 communicates with the sub-channel 234 through a gap between the second space R 2 and the cover 202. The pressure sensor 204 is mounted on the circuit board 207 at a position disposed in the second space R 2. Therefore, the pressure sensor 204 can measure the pressure in the second space R 2. The third space R 3 communicates with the outside of the measurement unit 213 at an R 3 inlet 255. The temperature and humidity sensor 206 is mounted on the circuit board 207 at a position disposed in the third space R 3. Therefore, the temperature and humidity sensor 206 can measure the temperature and humidity in the third space R 3. Incidentally, the pressure sensor 204 constitutes a first sensor that detects the pressure that is a first physical quantity of the measurement gas, and the temperature and humidity sensor 206 constitutes a second sensor that detects the temperature or the humidity that is a second physical quantity of the measurement gas.<Structure of Circuit Board>FIG. 6A is a front view of the circuit board on which the chip package and the circuit components are mounted, FIG. 6B is a cross-sectional view taken along the line VIB-VIB of FIG. 6A, and FIG. 6C is a cross-sectional view taken along the line VIC-VIC of FIG. 6A. Then, 7A is a view illustrating a configuration example of the circuit board.The circuit board 207 has a rectangular shape along the longitudinal direction of the measurement unit 213 as a whole. The circuit board 207 includes a receiving portion 207 aconfigured to receive a part of the chip package 208. As illustrated in FIG. 7A, the accommodating portion 207 ais formed by partially cutting out a portion of the circuit board 207 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.In the chip package 208, at least a part of a package body 271 in the thickness direction enters the accommodating portion 207 aof the circuit board 207 to be accommodated therein, as illustrated in FIGS. 6A, 6B, and 6C. Specifically, the assembly body 271 is accommodated in a state in which a package front side portion 271 c, which is a proximal end portion 271 aof the assembly body 271, and a portion of the assembly body 271 on which the flow rate sensor 205 is provided enter the accommodation portion 207 aof the circuit board 207.In the present embodiment, because the package front side portion 271 c, which is a part of the package body 271 in the thickness direction, is accommodated in the accommodation portion 207 aof 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 on the circuit board 207 together with the chip package 208. In addition, the mounting height of the mounting components can be suppressed to be lower as compared with a case where the chip package 208 is overlapped on the circuit board 207. Therefore, the height of the measurement unit 213 can be reduced, the physical quantity detection device 20 can be made thin as illustrated in FIG. 3B, and the flow resistance in the main passage can be reduced. Incidentally, in the present embodiment, the case where the package front side portion 271 cof the package body 271 is accommodated in the accommodation portion 207 aof the circuit board 207 has been described as an example, but may be configured such that the entire package body 271 is accommodated in the thickness direction. With such a configuration, it is possible to further promote the height reduction of the measurement unit 213 and reduce the thickness of the physical quantity detection device 20.< Position of Each Sensor>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 271 aof the package body 271, and is fixed to the circuit board 207 because these connection terminals 272 are connected to the contact surfaces 264 of the circuit board 207 by soldering. The flow rate sensor 205 and an LSI, which is an electronic component that drives the flow rate sensor 205, are mounted in the chip package 208. The flow rate sensor 205 is provided at a distal end portion 271 bof the assembly body 271. The chip package 208 constitutes a support body on which the flow rate sensor 205 as a flow rate detection unit and an LSI as a processing unit are mounted.In the configuration example illustrated in FIGS. 6A to 6C, the chip package 208 is fixed to the circuit board 207 such that the package front side portion 271 c, which is one side in the thickness direction of the chip package 208, is located on the back side of the circuit board 207, i.e., on the surface facing the cover 202. Therefore, the flow rate sensor 205 may be disposed to be opposed to the cover 202 which is a conductive member, and the static elimination may be performed in the flow rate sensor 205 and the periphery thereof. With this static elimination, the flow rate sensor 205 and its periphery can be prevented from being charged, the deposition of dust due to the adsorption force of the charge can be suppressed, and the high detection accuracy can be obtained.Incidentally, the chip package 208 may be mounted on the circuit board 207 such that the package front side portion 271 cprovided with the flow rate sensor 205 is located on the front side of the circuit board 207, i.e., on a surface side remote from the cover 202, as illustrated in FIG. 6D. In the chip package 208, the flow rate sensor 205 may be exposed on either the front side or the back side of the circuit board 207. Even in such a configuration, a part of the chip package 208 in the thickness direction may be accommodated in the accommodation portion 207 aof the circuit board 207 to suppress the overall mounting height, the height may be reduced, and the physical quantity detection device 20 may be thinned. In addition, the distance from a mounting surface of the circuit board 207 may be secured, the mounting height of the chip package 208 with respect to the circuit board 207 may be controlled, and a shape of the connection terminal described later may be secured.The pressure sensor 204 is mounted to be 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 to be closer to the other side of the circuit board 207 than the chip package 208 in the longitudinal direction. Then, the lead of the intake air temperature sensor 203 is connected to the circuit board 207. The intake air temperature sensor 203 is mounted so as to be disposed at a position where the lead 203 bis connected to a position located closer to the other side of the circuit board 207 than the temperature and humidity sensor 206 in the longitudinal direction, the sensor body 203 aprotruding from the circuit board 207 in the longitudinal direction so as to be exposed to the outside of the measurement unit 213.On the measurement unit 213, (1) the pressure sensor 204, (2) the flow rate sensor 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 protruding the measurement unit 213). (1) The pressure sensor 204 detects the pressure of the measurement gas 2, and the flow rate sensor 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 detects the temperature of the measurement gas 2.The physical quantity detection device 20 is disposed in an engine room of a motor vehicle, for example. The temperature in the engine room is 60° C. to 100° C., while the temperature of the measurement gas 2 passing through the main passage 22 is 25° C. on the average. Therefore, the heat in the engine room is transferred from the flange 211 side to the physical quantity detection device 20, and a temperature distribution thereof is given such that the temperature gradually decreases as it shifts from the flange 211 side toward the distal end portion side of the measurement unit 213.Therefore, in the measurement unit 213 of the present embodiment, (1) the pressure sensor 204 having the smallest thermal effect is disposed on the proximal end side, and then (2) the flow rate sensor 205 having a small thermal effect on the high temperature side is disposed closer to the distal end portion side of the measurement unit 213 than (1) the pressure sensor 204. Then, (3) the temperature and humidity sensor 206 having a small thermal effect on the low temperature side is disposed to be closer to the distal end portion side of the measurement unit 213 than (2) the flow rate sensor 205 next, and (4) the intake air temperature sensor 203 that is the most heat sensitive is disposed at the distal end portion of the measurement unit 213.Since the circuit board 207 according to the present embodiment is disposed to extend along the longitudinal direction of the measurement unit 213, heat conduction distance from the flange 211 to the vicinity of the central axis of the main duct 22 can be secured. Since the respective sensors ( 1) to ( 4) are arranged side by side from the proximal end portion to the distal end portion of the measurement unit 213 in ascending order of the heat action, the sensor performance of each sensor can be secured. In addition, the thermal conductivity to the air can be promoted by disposing the circuit board 207 on one side in the transverse direction of the measurement unit 213.In addition, the intake air temperature sensor 203 is connected to the circuit board 207. As illustrated in FIG. 6A, the intake air temperature sensor 203 is disposed to protrude from a distal end portion of the circuit board 207 along the longitudinal direction. The pair of leads 203 bof the intake air temperature sensor 203 are bent along the surface of the circuit board 207 and project from the distal end portion of the circuit board 207. On a board surface of the circuit board 207 facing the pair of leads 203 b, the pads 263 are provided, and the leads 203 bare soldered. The sensor body 203 ais supported by the pair of leads 203 bat a position spaced a predetermined distance from the circuit board 207.According to the present embodiment, the center of the circuit board 207 in the longitudinal direction is cut out to form the accommodating portion 207 a, with the proximal end portion 208 aof the chip package 208 accommodated therein. Then, the proximal end portion 208 aof the chip package 208 is provided with the plurality of connection terminals 272 protruding in the directions away from each other along the lateral direction of the package body 271. In the chip package 208, the distal end portion 271 bincluding the flow rate sensor 205 protrudes 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.On the circuit board 207, the plurality of pads 264 are provided so as to be divided into one side in the longitudinal direction of the circuit board 207 and the other side, which is a portion where the pads 264 oppose each other with the accommodation portion 207 atherebetween, the respective pads 264 being fixed by soldering. The chip package 208 has a stably supported structure in which both ends in the lateral direction of the proximal end portion 271 aof the package body 271 are supported by the circuit board 207.In addition, 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 divided into two sides in the extending direction of the second sub-channel groove 252 at predetermined intervals are connected to the pads 264 of the circuit board 207. Therefore, the chip package 208 may be mounted at a proper position with respect to the circuit board 207 when mounted on the 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.According to the present embodiment, the chip package 208 is disposed 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 a signal transmission path between the chip package 208 and each sensor, improve the signal transmission speed, and suppress the generation of noise.FIGS. 7B and 7C are views illustrating another configuration example of the circuit board.Although the case where the accommodation portion 207 aof the circuit board 207 is formed using a notch has been described as an example in the above-described embodiment, the accommodation portion may preferably accommodate a part of the chip package 208 in the circuit board 207, and may be formed using a groove or a depression.For example, as illustrated in FIG. 7B, a recessed portion may be provided on the front side of the circuit board 207 to form a receiving portion 207 b. The accommodating portion 207 bis continuous with a side surface of the circuit board 207 along a direction in which the distal end portion 271 bof the package body 271 of the chip package 208 protrudes. The thickness of the circuit board 207 is thin in the accommodating portion 207 bto allow at least a part of the chip package 208 to be inserted in the thickness direction. Therefore, as compared with the case where the chip package 208 is mounted on the circuit board 207 in an overlapping manner, the mounting height of the mounting components can be suppressed to be small, and the overall thickness of the measurement unit 213 can be reduced, which is similar to the above-described accommodating portion 207 a. As a result, the physical quantity detection device 20 can be made thin, and the flow resistance in the main passage can be reduced.In addition, in the above-described embodiment, the case where the accommodation portion 207 aof the circuit board 207 is provided at the center of the circuit board 207 in the longitudinal direction has been described, but the accommodation portion 207 amay be provided at another location. For example, as illustrated in FIG. 7C, an end portion of the circuit board 207 on the one side in the longitudinal direction may be cut out so that the overall shape of the circuit board 207 has a substantially L shape, with a notched portion used as the receiving portion 207 c.The receiving portion 207 callows the proximal end portion 271 aof the assembly body 271 to be inserted. Therefore, as compared with the case where the chip package 208 is attached to the front side of the circuit board 207 in an overlapping manner, the mounting height of the mounting components can be suppressed to be small, and the overall thickness of the measurement unit 213 can be reduced, which is similar to the above-described accommodating portion 207 a. As a result, the physical quantity detection device 20 can be made thin, and the flow resistance in the main passage can be reduced.<Konfiguration of Chip Package 208>FIG. 8A is a front view of the chip package, FIG. 8B is a rear view of the chip package, FIG. 8C is a side view of the chip package, FIG. 8D is a bottom view of the chip package, and FIG. 8E is an isometric view of the chip package.The chip package 208 is configured by attaching the LSI and the flow rate sensor 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 lateral direction of the measurement unit 213, so that the proximal end portion 271 aon one side in the longitudinal direction of the package body 271 is disposed in the circuit chamber 235, and the distal end portion 271 bon the other side in the longitudinal direction of the package body 271 is disposed in the second sub-channel groove 252.The chip package 208 is electrically conductive and integrally fixed to the circuit board 207 by soldering the plurality of connection terminals 272 provided at the proximal end portion 271 aof the package body 271 to the contact surfaces 264 of the circuit board 207. The flow rate sensor 205 is provided at a distal end portion 271 bof the assembly body 271. The flow rate sensor 205 is disposed to be exposed in the second sub-channel. The flow rate sensor 205 is provided in the channel groove 273 provided recessed on the surface of the assembly body 271. The passage groove 273 is formed to extend along the second sub passage groove 252 in the second sub passage groove 252 over the entire width from an end portion on one side in the lateral direction to an end portion on the other side in the lateral direction of the assembly body 271. The flow rate sensor 205 has a membrane structure. When the chip package 208 is molded with resin, the resin molding is performed by using an insert mold so that the resin does not flow into the surface of the flow rate sensor 205.FIG. 9 is a view illustrating a bent shape of the connection terminal according to the present embodiment, and FIG. 10 is a view illustrating a bent shape of a connection terminal according to a comparative example.As illustrated in FIG. 9, the connection terminal 272 of the chip package 208 includes: a protruding portion 272 awhich is a proximal end portion, a rising portion 272 b, a falling portion 272 c, and an end portion 272 dwhich is a distal end portion. The protruding portion 272 aprotrudes straight from the center of the assembly body 271 in the thickness direction along the transverse direction of the assembly body 271, the rising portion 272 bhas a shape rising from a distal end of the protruding portion 272 aby being bent toward a rear side portion 271 dof the assembly which is one side in the thickness direction of the assembly body 271. Then, the descending portion 272 cis of a shape continuous with the ascending portion 272 band descending so as to be bent toward the package front side portion 271 c, which is the other side in the thickness direction of the package body 271 at a first bending height position, and the end portion 272 dis of a shape continuous with the descending portion 272 cand protrudes in a direction away from the package body 271 at a second bending height position.The protruding portion 272 aand the end portion 272 dare located at different positions of the assembly body 271 in the thickness direction, the end portion 272 dis formed to be higher by δ than the protruding portion 272 aon the rear side portion 271 dside of the assembly, which is one side in the thickness direction of the assembly body 271. Then, when the proximal end portion 271 aof the package body 271 is accommodated in the accommodation portion 207 cof the circuit board 207, the protruding portion 272 a, which is the base of the connection terminal 272, is disposed to abut on an upper surface of the circuit board 207, and the end portion 272 dis disposed 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 272 abuts the upper surface of the circuit board 207 and the end portion 272 dis floated from the circuit board 207.The rising portion 272 band the falling portion 272 care formed to have gentle slopes such that a falling angle θa 2 of the falling portion 272 cis set to be larger than a rising angle θa 1 of the rising portion 272 b, the falling portion 272 cis inclined more than the rising portion 272 bwith respect to the circuit board 207, and an inclination of the falling portion 272 cis gentler. In the present embodiment, a solder 281 is used as a connecting member to connect the end portion 272 dand the contact surface 264 of the circuit board 207, and a so-called back solder fillet 281 ain which the solder 281 protrudes in a direction returning from the end portion 272 dalong the axial direction of the connection terminal 272 to the protruding portion 272 ais formed between the connection terminal 272 and the circuit board 207.A chip package 208' of the comparative example illustrated in FIG. 10 is disposed on the circuit board 207, and its connection terminals 272 include a protruding portion 272e, a falling portion 272f, and an end portion 272g. The protruding portion 272 ehas a shape protruding from the center of the assembly body 271 in the thickness direction along the transverse direction of the assembly body 271, while the falling portion 272 fhas a shape falling so as to be bent from a distal end of the protruding portion 272 etoward the rear side portion 271 dof the assembly. Then, the end portion 272 ghas a shape bent at a lower end of the descending portion 272 fin a direction away from the assembly body 271 and protruding along the lateral direction of the assembly body 271. The descending portion 272 fis formed to have an angle substantially perpendicular to the upper surface of the circuit board 207.When the chip package 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 package of the package body 271, a thickness h2 of the front surface portion 271c of the package, a gap h3 with respect to the circuit board 207 and a thickness h4 of the circuit board 207 (hb = h1 + h2 + h3 + h4). Since the chip package 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 a vertical strain in the Z direction, and a structure having a large mounting height is undesirable in terms of the lifetime of the solder.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 h 2 of the package back surface portion 271 dand the thickness h 1 of the circuit board 207 (ha=h 2+h 1). Therefore, the present embodiment can achieve height reduction as compared with the comparative example. Incidentally, in the present embodiment, the thickness of the circuit board 207 may be made equal to the thickness h 1 of the rear side portion 271 dof the package of the package body 271.In addition, according to the present embodiment, the descending portion 272 cof the connection terminal 272 is moderately inclined with respect to the circuit board 207, and thus a length L 1 of the rear solder fillet 281 acan be increased (L 2<L 1) as compared with the descending portion 272 fsubstantially perpendicular to the circuit board 207 of the comparative example. Therefore, the solder elongation can be reduced and the life of the solder can be prolonged. In addition, the rising portion 272 bof the connection terminal 272 has a smaller inclination angle than the falling portion 272 c, so that the total protrusion amount of the connection terminal 272 can be shortened and the chip package 208 can be miniaturized.In the comparative example, the end portion 272 gprovided at the folded distal end of the connection terminal 272 is disposed on the contact surface of the circuit board 207 and soldered. Consequently, positioning of the chip package 208 with respect to the circuit board 207 is difficult, and there is a problem that the terminal height varies greatly, which affects the positional accuracy of the flow rate sensor 205. On the other hand, in the present embodiment, a part of the chip package 208 is accommodated in the accommodation portion 207 a, and the protruding portion 272 awhich is the base of the connection terminal 272 is disposed on the circuit board 207, whereby the chip package 208 is positioned. Therefore, as compared with the comparative example, it is easier to position the chip package 208 with respect to the circuit board 207, and there is an advantage that the accuracy of the position of the flow rate sensor is high.FIG. 11 is a graph illustrating the relationship between the bending height of the connection terminal and an equivalent strain, and is the graph illustrating prediction of the lifetime of the connection terminal upon temperature change. According to the present embodiment, a sufficient lifetime can be ensured even when the terminal height of the connection terminal 272 of the chip package 208 is smaller than that of the chip package 208. In addition, the terminal height of the connection terminal 272 can be increased to the surface height position of the adjacent pressure sensor 204, and thus there is no limitation on the moldability of the connection terminal 272 even if the height is decreased as in the present embodiment, and the reliability of the mechanical connection of the chip package 208 can be further improved.Incidentally, the case where the solder is used as the connection member connecting between the contact surface 264 of the circuit board 207 and the connection terminal 272 has been described in the above embodiment, and the present invention is not limited thereto, and for example, a welding alloy or a conductive adhesive may be used.FIG. 12 is a view illustrating a configuration in which a sensor is directly mounted on a circuit board, and is a plan view illustrating a modification of the circuit board 207 illustrated in FIG. 6A.The sensing element including a flow rate sensing unit 205' may be mounted on a circuit board 207' via a support body 209 fixed to the circuit board 207', which is a printed circuit board. With this configuration, the stress acting on the measurement members can be reduced as compared with a case where components such as the measurement members including the flow rate measurement unit 205' are directly mounted on the circuit board 207, and the durability and reliability of the physical quantity detection device 20 can be improved. Incidentally, the mounting of the components on the circuit board 207 includes, for example, mounting the components on the circuit board 207 and electrically connecting the components to a wiring of the circuit board 207. The examples of the support body 209 include a metal lead frame, an LTCC board, a printed circuit board, and the like on which an electric wiring may be formed. A hole or a protrusion for positioning with respect to the housing 201 may be formed on the support body 209, and a configuration in which positioning is performed using the positioning protrusion or hole formed in the housing 201 may be adopted.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 can be made without departing from the spirit of the present invention as set forth in the claims. The above-described embodiments have been described in detail, for example, to describe the present invention in an easily comprehensible manner, and 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. Further, regarding some configurations of each embodiment, addition, deletion, or replacement of other configurations may be performed.List of Reference Numerals1 Internal combustion engine control system 2 Measurement gas 20 Physical quantity detection device 22 Main passage 201 Housing 202 Cover 203 Intake air temperature sensor 204 Pressure sensor 205 Flow rate sensor 206 Temperature and humidity sensor 207 Circuit board 208 Chip package 211 Flange 212 Connector 213 Measurement unit 214 Connector terminal 221 Front 222 Rear 223 One-side side surface 224 Other-side side surface 226 Lower surface 231 Sub passage inlet 232 First outlet 233 Second outlet 234 Sub passage 235 Circuit chamber 237 Rib (lower surface of the circuit chamber) 240 Ventilation passage 241 Fixing hole 242 Through hole 243 First rib 244 Second rib 245 Third rib 246 Fourth rib 247 Outer terminal 248 Correction terminal 249 Ventilation hole (ventilation passage outlet) 250 Sub passage groove 251 First sub passage groove 252 Second sub passage groove 253 Protrusion 254 Ventilation hole (ventilation passage inlet) 255 r3 inlet 256 ventilation groove 263 contact surface (for inlet air temperature sensor) 264 contact surface (for chip package terminal) 265 positioning hole 271 package body 272 connection terminal 273 channel groove

Claims

A physical quantity detection device (20) comprising: a support body on which a flow rate detection unit and a processing unit are mounted; and a circuit board (207) having a receiving portion (207a) in which a portion of the support body is accommodated, in the support body, at least a portion in a thickness direction of the support body is accommodated in the receiving portion (207a), and a portion including the flow rate detection unit protrudes from the receiving portion (207a), characterized in that the receiving portion (207a) is formed by cutting out a part of the circuit board (207).The physical quantity detection device (20) according to claim 1, wherein the support body is fixed to locations of the circuit board (207) facing each other, the accommodating portion (207a) of the circuit board (207) being disposed between the locations.The physical quantity detection device (20) according to claim 2, wherein the support body has a plurality of connection terminals (272) protruding in directions away from each other, and the plurality of connection terminals (272) and the circuit board (207) are connected by a connection member that is electrically conductive.The physical quantity detection device (20) according to claim 3, further comprising: a circuit chamber (235) accommodating the circuit board (207); and a sub-channel (234) disposed on a lateral side of the circuit chamber (235) and through which a measurement gas flows, wherein the flow rate detection unit is disposed in the support body in the sub-channel (234).The physical quantity detection device (20) according to claim 4, wherein in the support body, a portion including the flow rate detection unit protrudes in a direction orthogonal to a channel direction of the sub-channel (234), and the plurality of connection ports (272) are arranged so as to be divided into one side and another side in the channel direction of the sub-channel (234).The physical quantity detection device (20) according to claim 5, wherein in the circuit board (207), a first sensor that detects a first physical quantity and a second sensor that detects a second physical quantity are disposed on the one side and on the other side in the channel direction of the sub-channel (234), the accommodation portion (207a) being disposed between the first sensor and the second sensor.The physical quantity detection device (20) according to claim 6, wherein the proximal end portions of the plurality of connection terminals (272) abut on the circuit board (207), the distal end portions of the plurality of connection terminals (272) have a predetermined gap with respect to the circuit board (207), and the connection member is disposed between the distal end portions of the plurality of connection terminals (272) and the circuit board (207).The physical quantity detection device (20) according to claim 7, wherein each of the plurality of connection terminals (272) includes: a protruding portion that protrudes straight from the support body; a rising portion that rises by being bent at a distal end of the protruding portion toward one side in the thickness direction of the support body; a falling portion that is continuous with the rising portion and falls by being bent at a first bending height position toward another side in the thickness direction of the support body; and an end portion that is continuous with the falling portion and protrudes at a second bending height position in a direction away from the support body, and an inclination of the falling portion is gentler than an inclination of the rising portion.The physical quantity detection device (20) according to claim 8, wherein the connection member is a solder (281).

Images