JP2004205528A - Device for measuring air flow rate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring air flow rate which is high in reliability and precision, by restraining a thermal influence caused by a self heat generation of a power transistor. <P>SOLUTION: The power transistor 1 is mounted on a metal electric power terminal 40, independently separated from an electronic circuit board 7 arranged with other electronic elements. The electric power terminal 40 is a terminal for an electric power input, a part of which is exposed in the inside of the air passage of a suction tube 20. The heat generation of the power transistor 1 is radiated effectively by the metal terminal 40, without affecting the other electronic circuit elements to a large extent, thermal effects generated by the power transistor 1 with respect to the other electronic circuit composite elements are lightened, without increasing the number of parts. Consequently, the air flow rate measuring device of high measuring precision and high reliability can be realized. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an air flow rate measuring device for measuring an air flow rate flowing into an intake air passage of an intake system of an internal combustion engine, and more particularly to a heat generating temperature sensitive resistor for measuring an air flow rate taken into an engine of an automobile or the like. The present invention relates to an air flow measuring device used.

  The most common method for accurately controlling the air-fuel ratio of an internal combustion engine is to measure the intake air flow rate and sequentially calculate a fuel injection amount at which the combustion state is optimal. For this, an air flow measuring device for measuring the intake air flow is indispensable.

  In view of the above, various conventional air flow rate measuring devices have been proposed and are widely used today. One of these methods is a thermal air flow meter that can detect the mass flow rate of air.

  This thermal air flow meter includes a temperature-sensitive resistor disposed in an intake air flow path as an air flow detecting element, and is electrically connected to a detecting circuit.

  This detection circuit is also called a control circuit, and supplies current to the heater itself or a heater provided in the vicinity thereof to generate heat. At this time, the temperature of the temperature sensitive resistor changes the air taken into the internal combustion engine. The magnitude of the supply current is controlled so that the temperature is always higher than the temperature by a constant temperature.

  When air flows through the temperature-sensitive resistor, the amount of heat deprived of the temperature-sensitive resistor increases, and the rate changes according to the speed at which the air flows. Accordingly, the value of the current supplied to the temperature-sensitive resistor or the heater Also change.

  As a result, the amount of change in the heating current supplied to the temperature-sensitive resistor becomes a value corresponding to the air flow rate.

  Also, in order to obtain an accurate heat radiation amount of the heating temperature sensitive resistor, it is necessary to detect the temperature of the air to be measured. Therefore, another temperature sensitive resistor is used as an intake air temperature detecting element in the intake air flow path. Has been placed.

  The electric signal representing the detected air flow rate is input to an output processing circuit, where it is processed so as to be compatible with an input voltage range required for the engine control device, and output as an output signal of the air flow measurement device.

  As a configuration using such a technique, for example, there is an air flow measuring device described in Japanese Patent Application Laid-Open No. 9-4487. This air flow measuring device is an excellent technology that can cool the heat generated from the electronic circuit board by the intake air by inserting the module housing containing the electronic circuit board inside the intake pipe. is there.

  As other examples of the air flow measuring device, Japanese Patent Application Laid-Open No. Hei 5-231899 and Japanese Patent Application Laid-Open No. Hei 9-503310 (corresponding to USP 5, 631, 416).

JP-A-9-4487

JP-A-5-231899 Japanese Patent Publication No. 9-503310 (corresponding to USP 5, 631, 416)

  However, in the prior art described in Japanese Patent Application Laid-Open No. 9-4487, the heat generated from the electronic circuit board is cooled by the intake air, but when the amount of heat to be cooled changes depending on the size of the intake air. It cannot be said that thermal effects on electronic circuit components are sufficiently considered.

  That is, in the thermal air flow measuring device, a current is supplied to the temperature-sensitive resistor to generate heat, and therefore, a power transistor is mounted on an electronic circuit in order to obtain a supply current required for heat generation.

  The power transistor generates heat when the current is amplified, and thus has a thermal effect on peripheral members and electronic circuit elements.

  The electronic circuit board of the air flow rate measuring device reduces the number of components and the number of mounting processes by mounting all electronic circuit components on the same circuit board except for the temperature sensitive resistor that detects the air flow rate and air temperature. Cost reduction and product miniaturization.

  Therefore, the power transistor is mounted on an electronic circuit board, and the heat of the power transistor conducts heat to the mounted circuit board, conducts heat to the metal base joining the circuit board, and removes the peripheral members and other components. This has a thermal effect on the electronic circuit element.

  Since the air flow measuring device is mainly located inside the intake pipe of the automobile engine, the heat of the electronic circuit board is carried away by the intake air. Have different air velocities. In particular, when the engine is idling, if the air flow rate is relatively slow and the heat of the circuit board cannot be taken away, there is a problem with the electronic circuit due to the heating of the circuit board and the temperature dependence of each element and resistor. There is a problem that a measurement error or a detection error occurs due to thermal influence of the temperature-sensitive resistor.

  An object of the present invention is to realize a highly reliable and highly accurate air flow measuring device by suppressing a thermal effect caused by self-heating of a power transistor.

  In order to achieve the above object, the present invention is configured as follows.

  (1) A flow rate detecting element for measuring an air flow rate, an electronic circuit electrically connected to the flow rate detecting element, for controlling the flow rate detecting element and outputting a signal corresponding to the air flow rate, and protecting the electronic circuit. A power transistor is supported by the terminal in an air flow measuring device having an internal housing and a terminal outside the housing for connecting the electronic circuit to an external device.

  (2) Preferably, in (1), the flow detection element is a temperature-sensitive resistor that generates heat by applying a current, and the power transistor amplifies and controls the current to the heat-generating temperature-sensitive resistor. You.

  (3) Preferably, in the above (1) or (2), a collector electrode of the power transistor is joined to the terminal, and a base electrode and an emitter electrode are respectively connected to the electronic circuit by a conductive member. .

  (4) Preferably, in the above (1), (2) or (3), the terminal is made of a copper-based metal having high thermal conductivity.

  (5) Also, preferably, in the above (1), (2), (3) or (4), the electronic circuit is disposed inside a conduit forming an air passage, and the terminal is connected to the conduit The heat generated from the power transistor is conducted to the outside of the conduit by the terminal.

  (6) Preferably, in the above (1), (2), (3), (4) or (5), the terminal for supporting the power transistor extends from the inside of the housing to the passage through which air flows. It extends and a part of the terminal is exposed to the air.

  (7) Preferably, in the above (1), (2), (3), (4), (5) or (6), the terminal supporting the power transistor has an inductance component.

  (8) Preferably, in (1), (2), (3), (4), (5), (6) or (7), the housing is made of resin, and the terminal is It is configured by plating wiring on the resin housing using MID technology.

  (9) A flow rate detecting element for measuring the air flow rate, an electronic circuit electrically connected to the flow rate detecting element, for controlling the flow rate detecting element and outputting a signal corresponding to the air flow rate, and protecting the electronic circuit. In an air flow measuring device having an internal housing and a terminal for connecting the electronic circuit and an external device outside the housing, the housing is made of resin, and a metal plate is insert-molded on the resin housing. The power transistor is supported by the metal plate.

  (10) Preferably, in the above (9), the terminal for communicating with the external device is a metal terminal, and the metal plate is formed together with the metal terminal, and is insert-molded into the resin housing. After that, it is separated from the metal terminal.

  In the air flow measuring device, the power transistor is supported by terminals outside a housing that houses the circuit board.

  As a result, the amount of heat generated by the power transistor can be radiated to the terminal, the temperature rise of the power transistor itself can be reduced, and direct heating of the electronic circuit board can be prevented.

  The terminal can be made of a copper-based material having a high thermal conductivity to increase the heat radiation effect.

  Further, the terminal supporting the power transistor is extended from the inside of the housing to a position exposed to the intake air, is exposed from the housing, and has a structure in which heat is radiated from the exposed terminal, so that the heat radiation effect is improved.

  ADVANTAGE OF THE INVENTION According to this invention, the heat influence resulting from self-heating of a power transistor can be suppressed and a highly reliable and highly accurate air flow measuring device can be realized.

  Furthermore, by using a copper-based material having high thermal conductivity for the metal terminals, the power transistor mounting portion, which is a member to which heat is to be transmitted, can efficiently transfer heat, and conversely, peripheral members and electronic circuit components that do not want to transfer heat Can further reduce the heat effect.

  For this reason, it is possible to prevent the detection accuracy of the temperature-sensitive resistor for detecting the temperature from being lowered, and to eliminate a factor that lowers the output characteristic accuracy.

  In addition, since the collector electrode of the power transistor is directly joined to the power supply terminal, and the base electrode and the emitter electrode are joined to the circuit board with metal wires, it is possible to electrically configure the circuit and only for the purpose of heat dissipation The object can be achieved without providing another heat radiating component.

  As a result, a physical quantity detection device and an air flow measurement device with high reliability and high measurement accuracy can be provided.

  In addition, if the metal terminal for mounting the power transistor is configured to have a portion formed in a coil shape, it is possible to suppress the thermal effect due to the self-heating of the power transistor and improve the accuracy. Even when a high-frequency current such as electromagnetic noise is applied, an air flow measuring device capable of supplying stable power to an electronic circuit can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a state in which an air flow measuring device according to a first embodiment of the present invention is attached to an intake pipe, and FIG. 2 is a schematic cross-sectional view taken along line AA of FIG. . FIG. 3 is a schematic side view of the air flow measuring device shown in FIG.

  1 to 3, a temperature-sensitive resistor 3 for detecting an air flow rate and a temperature-compensating temperature-sensitive resistor 4 for detecting a temperature are provided by an intake pipe through which air 23 introduced into the internal combustion engine flows. The temperature-sensitive resistor 3 and the temperature-compensating temperature-sensitive resistor 4 that are arranged inside the electronic circuit board 20 are also electrically connected to the electronic circuit board 7 that is similarly arranged inside the intake pipe 20.

  The electronic circuit board 7 is formed by molding alumina ceramics that can withstand high temperatures into a plate shape in consideration of being installed in an engine room of an automobile. Then, a thick film conductor or a thick film resistor paste is printed on the surface of the alumina ceramics, and thereafter, a conductor and a resistor pattern are formed by firing. A semiconductor element 8 such as an operational amplifier is mounted on the conductor pattern by soldering or the like.

  Of course, there may be other electronic circuits, such as a molded package IC, which are different from the first embodiment of the present invention. However, since the effects are the same, the description of the other electronic circuits will be omitted.

  The electronic circuit board 7 is adhered and fixed to a base plate 11 made of sheet metal, and is surrounded by a resin housing 10 over substantially the entire periphery of a side surface of the electronic circuit board 7 so as to be protected by the resin housing 10. The base plate 11 made of sheet metal is integrated with the resin housing 10 by adhesive bonding or insert molding.

  In addition, it is also possible to adopt a configuration in which the electronic circuit board 7 is fixed and protected by a box-shaped resin housing including the bottom surface without using the sheet metal base plate 11.

  The resin housing 10 is a plastic component, and has metal columns 43, 44, 45 for holding the temperature-sensitive resistor 3 for detecting the air flow rate and the temperature-sensitive resistor 4 for detecting the air temperature by welding or the like. 46, and metal terminals 40, 41, 42 for connecting the electronic circuit board 7 built in the resin housing 10 to external devices are insert-molded.

  Further, the resin housing 10 integrates a sub-air passage 12 for passing a part of the air 23 sucked into the internal combustion engine and a connector 9 for connection with an external device.

  The characteristics of the electronic circuit board 7 are adjusted as required, and a plate-shaped resin cover is fixed to the resin housing 10 by bonding or the like, so that the electronic circuit board 7 is hermetically protected.

  The electronic circuit board 7, the auxiliary air passage 12, and the temperature-sensitive resistors 3, 4 incorporated in the resin housing 10 are arranged inside an intake pipe 20 through which air 23 introduced into the internal combustion engine flows. The connector 9 integrated with the resin housing 10 is fixed so as to be located outside the intake pipe 20.

  The metal input / output terminals 40, 41, and 42 disposed in the connector 9 penetrate from the inside of the resin housing 10 to the inside of the connector 9, and are connected to the electronic circuit board 7 by a conductive member such as a metal wire. It is electrically connected.

  The metal input / output terminals include a power supply terminal 40 to which electric power required for driving the air flow measuring device is supplied, an output terminal 41 for outputting a flow signal of the air flow measuring device, and a circuit of the electronic circuit board 7. And a ground terminal 42 which is a ground (earth) line serving as a reference potential.

  The metal power supply terminal 40 penetrates from the inside of the connector 9 to the inside of the resin housing 10, and is simultaneously pressed with the other input / output terminals 41 and 42 so as to have a shape extended to a position exposed to the intake air 23. It is formed so as to be exposed inside the intake pipe 20 but outside the resin housing 10 (see FIG. 3). Therefore, the exposed metal power supply terminal 40 is cooled by the intake air in the intake pipe 20.

  The power supply terminal 40 is a power transistor for electrically connecting the electronic circuit board 7 with a conductive member similarly to the other input / output terminals 41 and 42 and for amplifying a current supplied to the heat-sensitive resistor 3. 1 is mounted (or supported) by soldering or the like.

  FIG. 4 is a circuit diagram of an air flow measuring device using a heat-sensitive resistor. The temperature sensitive resistor 3 needs to generate heat in order to detect an air flow rate according to the magnitude of heat radiation, and amplifies the current by using the power transistor 1 to supply a current required for heat generation.

  In FIG. 4, the control circuit 2 of the air flow measuring device is basically constituted by a bridge circuit. By inputting the voltages at two midpoints of the bridge to an operational amplifier 7, the respective voltages are compared with each other. It is controlled to be a voltage.

  The two temperature-sensitive resistors 3 and 4 arranged in the air passage 20 are electrically connected to the control circuit 2 as a part of a resistor constituting a bridge circuit, and are operated by an operational amplifier 7 provided in the control circuit 2. Is controlled.

  In configuring the air flow measuring device, it is desirable that all electronic circuit components other than the temperature sensitive resistors 3 and 4 that detect the air flow and the air temperature be mounted on the same circuit board.

  This is because the number of components can be reduced, the cost can be reduced by reducing the number of mounting steps, and the size of the product can be reduced.

  However, since the power transistor 1 generates heat during current amplification, mounting the power transistor and other electronic circuit elements on the same substrate causes a problem that heat affects electronic circuit elements and the like around the power transistor. .

  Regarding the thermal durability of the semiconductor element 8 such as an operational amplifier, the semiconductor element 8 is mounted on a ceramic substrate having good heat conductivity, and is bonded to a sheet metal base plate 11 constituting the bottom surface of the circuit case. Is not a problem because it can dissipate heat to some extent.

  The thick film resistor printed and baked on the surface of the semiconductor element 8 or the ceramic substrate has a temperature dependency in output characteristics and resistance value, and has a function of changing circuit characteristics. By constructing a temperature compensation circuit in the electronic circuit so that the output can be corrected even when a temperature change occurs, it is possible to cope with the heat generation of the power transistor so that the influence is not affected to some extent.

  However, when the power transistor 1 is mounted on the electronic circuit board 7, the heat of the ceramic substrate 7 heated by the self-heating of the power transistor 1 is transmitted to the base plate 11 made of sheet metal to which the substrate 7 is fixed by bonding or the like. The base plate 11 made of metal having high conductivity warms up as a whole.

  Here, the temperature-sensitive resistor 4 that detects the temperature of the intake air 23 is disposed inside the auxiliary air passage 12, and one side wall of the temperature-sensitive resistor 4 is configured by a base plate 11 made of a sheet metal, and the other side. Are formed by a resin housing 10.

Therefore, when the heat of the power transistor 1 is conducted to the base plate 11, the heat of the base plate 11 is further transferred to the air inside the auxiliary air passage 12.
For this reason, the temperature-sensitive resistor 4 that detects the temperature of the intake air is affected by the heat generated by the self-heating of the power transistor 1 and causes an error in the detected temperature.

  Of course, since the air flow measuring device is disposed in the intake pipe 20 of the internal combustion engine, the intake air 23 has a flow velocity according to the output of the internal combustion engine, and thus takes away the heat of the base plate 11, but changes in the air flow velocity Causes a difference in the amount of heat transfer.

  In other words, when the flow velocity of the intake air 23 is extremely low, such as about 0.5 m / s, the base plate 11 substantially dissipates heat during natural convection, and has a thermal effect on the temperature-sensitive resistor 4. Conversely, when the flow rate of the intake air 23 is high, the heat of the base plate 11 is almost taken away by the air and cooled, so that the temperature inside the auxiliary air passage 12 becomes equal to the temperature of the intake air. The flow rate dependency of the temperature detection error due to this thermal effect becomes a problem.

  Therefore, the circuit board 7 and the metal base plate 11 are formed by mounting the power transistor 1 on the metal power supply terminal 40 integrated with the resin housing 10 by soldering or a conductive adhesive. Is less susceptible to heat. Thereby, the temperature sensing resistor 4 for temperature detection can reduce the detection error, and can realize an air flow measuring device with high measurement accuracy.

  In addition, since the metal terminals 40 are exposed from the resin housing 10, the metal terminals 40 function as heat sinks, so that the heat effect of the power transistor 1 due to self-heating can be reduced.

  By the way, since the temperature sensing resistor 4 is thermally affected by the sheet metal base plate 11, it is described whether the thermal effect of the temperature sensing resistor 4 can be improved by replacing it with a resin base plate. .

  When the sheet metal base plate 11 is formed of a resin base plate, the resin has a lower thermal conductivity than a metal, that is, a higher thermal conductivity, so that only the vicinity of the ceramic substrate on which the power transistor 1 is mounted is thermally affected. In addition, the influence of heat inside the sub air passage 12 surrounding the temperature sensing resistor 4 for temperature detection is reduced. Conversely, since heat radiation is worse than that of the base plate 11 made of metal, heat is trapped inside the housing 10 containing the electronic circuit board 7.

  Since the air flow measuring device is mainly used for automobiles, it is exposed to a high temperature environment. In addition to the heat generated by the self-heating of the power transistor 1, the radiated heat generated by the engine affects the air flow measuring device. There is a possibility that the temperature may exceed the high temperature side temperature compensation range of the semiconductor element 8 and the like mounted on the device.

  In addition, since the heat radiation from the base plate 11 is suppressed, heat is conducted to the conductive support 46 for fixing the temperature-sensitive resistor 4 integrally formed in the housing 10 by welding or the like, and the air-temperature detecting sensor 4 is a problem for air temperature detection. The thermal resistor 4 may be affected by heat.

  Therefore, it is difficult to improve the thermal effect of the temperature sensing resistor 4 by replacing the sheet metal base plate 11 with a resin base plate.

  As described above, according to the first embodiment of the present invention, the power transistor 1 is mounted on the metal power supply terminal 40 independently and separately from the electronic circuit board 7 on which other electronic circuit elements are arranged. By having a structure in which a part of 40 is exposed in the air passage, it is possible to reduce the thermal influence on other electronic circuit components due to the self-heating of the power transistor 1 without increasing the number of parts, and the measurement accuracy is improved. And a highly reliable air flow measuring device can be realized.

  Note that electrically, one surface of the power transistor 1 is constituted by a collector electrode and the other surface is constituted by two poles of a base electrode and an emitter electrode, and the collector electrode of the power transistor 1 is provided on the power supply terminal 40. Electrical connection can be achieved by joining with solder or a conductive adhesive. Then, the other base electrode and emitter electrode of the power transistor 1 and the electronic circuit board are joined using a conductive member such as a metal wire.

  Thus, the power supply terminal 40 can be used as a component of an electronic circuit as well as an effect as a heat radiating member, and effectively radiates heat generated by the power transistor 1 without providing a separate heat radiating component only for heat radiation. be able to.

  Further, by using a copper-based material having a high thermal conductivity for the metal terminal 40, heat can be efficiently transmitted to the mounting portion of the power transistor 1, which is a member to which heat is to be transmitted, and on the other hand, peripheral members that do not want to transmit heat and Thermal effects on electronic circuit components can be further reduced.

  FIG. 5 is a schematic configuration diagram showing a state in which the air flow measuring device according to the second embodiment of the present invention is attached to an intake pipe, and FIG. 6 is a schematic sectional view taken along line BB of FIG.

  In the second embodiment, the power transistor 1 is mounted not on the power supply terminal 40 but on a separately provided metal plate 50, and the other configuration is the same as that of the above-described first embodiment. .

  5 and 6, a metal plate 50 on which the power transistor 1 is mounted is formed by pressing or the like at the same time as the metal power supply terminals 40 and the like arranged in the connector 9 and is made of the same material as the metal terminals 40 and the like. Yes, like the power supply terminal 40 in the first embodiment, it is insert-molded in the housing 10.

  By using, for example, a copper-based material having a high thermal conductivity, the metal plate 50 can actively conduct heat to the metal plate 50 due to self-heating of the power transistor 1.

  The metal plate 50 is an effective means when it is difficult to mount the power transistor 1 on the metal power supply terminal 40 due to an electronic circuit configuration.

  As described above, also according to the second embodiment of the present invention, it is possible to reduce the influence of heat on the electronic circuit board 7, the base plate 11, and the temperature-sensitive resistors 3 and 4, and to achieve high reliability with good measurement accuracy. An air flow measuring device can be realized.

  FIG. 7 is a schematic configuration diagram showing a state where an air flow measuring device according to a third embodiment of the present invention is attached to an intake pipe.

  In the third embodiment, the power transistor 1 is connected to the power supply terminal 40 as in the first embodiment, but the shape of the power supply terminal 40 is different from that of the first embodiment. Other configurations are the same as the first embodiment and the third embodiment.

  The metal power supply terminal 40 has a coil shape in the connector 9 so that the direction of the supplied current is alternated so as to have an inductance component.

  Even when a high-frequency current such as electromagnetic wave noise is applied to the power supply terminal 40 having a coil-shaped portion, the direction of the current is alternated, so that a back electromotive force is generated and the noise is converted into heat. There is an operation of supplying stable electric power to the electronic circuit 7.

  As described above, according to the third embodiment of the present invention, the same effects as those of the first embodiment can be obtained, and even when a high-frequency current such as electromagnetic noise is applied, the electronic circuit 7 can be used. An air flow measuring device capable of supplying stable power to the air flow can be realized.

  The connector terminals such as the power supply terminal 40, the output signal terminal 41, and the ground terminal 42 described above can also be formed by plating wiring on the resin housing 10 by using MID (Molded Interconnection Device) technology.

  Further, the above-described example is an example in which the present invention is applied to a case where the present invention is used for controlling current to a heat-generating thermosensitive resistor. However, the present invention is not limited to this, and a power transistor is used. This is applicable to an example in which heat generated by the device affects surrounding electronic circuit elements.

1 is a schematic configuration diagram illustrating a state in which an air flow measuring device according to a first embodiment of the present invention is attached to an intake pipe. FIG. 2 is a schematic sectional view taken along line AA of FIG. 1. It is a schematic side view of the air flow measuring device shown in FIG. FIG. 3 is a circuit diagram of an air flow measuring device using a heat-sensitive resistor. It is a schematic structure figure in the state where an air flow measuring device which is a 2nd embodiment of the present invention was attached to an intake pipe. FIG. 6 is a schematic sectional view taken along line BB of FIG. 5. It is a schematic structure figure in the state where an air flow measuring device which is a 3rd embodiment of the present invention was attached to an intake pipe.

Explanation of reference numerals

1 power transistor 2 control circuit
3 Temperature-sensitive resistor for detecting air flow rate 4 Temperature-sensitive resistor for detecting air temperature 5 Resistance 6 Resistance 7 Electronic circuit (board)
Reference Signs List 8 semiconductor element 9 connector 10 resin housing 11 metal base plate 12 auxiliary air passage 20 body (intake pipe constituent member)
40 Power supply terminal
41 output signal terminal 42 ground (earth) terminal 43, 44 conductive support 45, 46 conductive support 50 metal plate

Claims (10)

A flow rate detecting element for measuring an air flow rate, an electronic circuit electrically connected to the flow rate detecting element, for controlling the flow rate detecting element and outputting a signal corresponding to the air flow rate, and a housing for protecting the electronic circuit; And, in the air flow measuring device having a terminal for communicating the electronic circuit and the external device outside the housing,
An air flow measuring device, wherein a power transistor is supported by the terminal.   2. The air flow measuring device according to claim 1, wherein the flow detecting element is a temperature-sensitive resistor that generates heat by applying a current, and the current to the heat-generating temperature-sensitive resistor is amplified and controlled by the power transistor. An air flow measuring device, characterized in that:   3. The air flow measuring device according to claim 1, wherein a collector electrode of the power transistor is joined to the terminal, and a base electrode and an emitter electrode are respectively connected to the electronic circuit by a conductive member. Air flow measurement device.   4. The air flow measuring device according to claim 1, wherein the terminal is made of a copper-based metal having a high thermal conductivity.   5. The air flow measuring device according to claim 1, wherein the electronic circuit is disposed inside a conduit forming an air passage, and the terminal is disposed outside the conduit. Wherein the heat generated from the power transistor is conducted to the outside of the conduit by the terminal.   The air flow measuring device according to any one of claims 1, 2, 3, 4, and 5, wherein a terminal supporting the power transistor extends into a passage through which air flows from inside the housing. An air flow measuring device characterized in that a part of the air flow is exposed to the air.   The air flow measuring device according to any one of claims 1, 2, 3, 4, 5, and 6, wherein the terminal supporting the power transistor has an inductance component. .   The air flow measuring device according to any one of claims 1, 2, 3, 4, 5, 6, and 7, wherein the housing is made of resin, and the terminal is made of the resin using MID technology. An air flow measurement device characterized by being formed by plating wiring on a housing. A flow rate detecting element for measuring an air flow rate, an electronic circuit electrically connected to the flow rate detecting element, for controlling the flow rate detecting element and outputting a signal corresponding to the air flow rate, and a housing for protecting the electronic circuit; And, in the air flow measuring device having a terminal for communicating the electronic circuit and the external device outside the housing,
An air flow measuring device, wherein the housing is made of resin, and a metal plate is insert-molded in the resin housing, and a power transistor is supported by the metal plate. 10. The air flow measuring device according to claim 9, wherein the terminal for communicating with the external device is a metal terminal, and the metal plate is formed together with the metal terminal and is insert-molded into the resin housing. An air flow measuring device, which is separated from the metal terminal later.

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