JP2018026508A - Electronic circuit device and rotary electric machine including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized electronic circuit device capable of suitably radiating heat from a circuit element to the exterior, and to provide a rotary electric machine including the same.SOLUTION: A motor housing 11 of an electric motor is attached with a circuit board 12 on which an inverter circuit is formed. To the motor housing 11, a structure member 15 formed by a plate having a heat transmission property is fixed. The structure member 15 is attached to the motor housing 11 so that a lower surface of a bottom part 15b is opposed to a circuit element 14 mounted on the circuit board 12. On an upper surface of the bottom part 15b of the structure member 15, a choke coil 21 for noise reduction included in the inverter circuit is attached. The choke coil 21 is electrically connected with the circuit board 12 by being soldered after a plurality of coil terminals 212 are inserted into through holes formed on the circuit board 12.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electronic circuit device that performs signal processing or power conversion, and a rotating electrical machine including the electronic circuit device.

  The present invention relates to a choke coil fixing structure in which a pair of mounting plates are attached to a choke coil via support rods each formed of an insulating material, and a lower end portion of the mounting plate is fastened to a metal container (hereinafter referred to as a fixed side member). There was a prior art (see, for example, Patent Document 1). According to the fixing structure, the choke coil can be firmly fixed to the fixed side member with a simple configuration. Therefore, even if vibration is applied to the choke coil, the choke coil can be firmly held at a predetermined position by the mounting plate. Further, since the choke coil can be attached at a predetermined distance from the fixed member, another circuit element can be attached between the choke coil and the fixed member. For this reason, the substantial occupation area of the choke coil on the stationary member can be reduced, and the entire apparatus provided with the stationary structure can be reduced in size.

Japanese Utility Model Publication No. 6-48820

  By the way, a certain type of circuit element, such as a choke coil, may generate heat due to its operation. As a result, the generated heat is conducted to other circuit elements included in the electronic circuit device through radiation or metal in the circuit board, thereby inducing malfunction of the circuit element or allowing self-heating. The value was sometimes lowered. Therefore, it has been an important issue for the electronic circuit device to form a heat dissipation path in the electronic circuit device so that the heat from the heat source is not conducted to other circuit elements. Furthermore, when a circuit element having a large dimension in the height direction, such as a choke coil, is mounted on a circuit board, the distance between the housing surrounding the circuit board and the circuit board inevitably increases. For this reason, there is a problem that heat generated from other circuit elements on the circuit board is difficult to be transmitted to the housing, and heat dissipation is difficult.

Even in the above-described choke coil fixing structure according to the prior art, no consideration has been given to these problems. When the fixing structure is provided on the circuit board, the heat generated by the choke coil is transmitted to the circuit board through the mounting plate, so that the influence of heat on other circuit elements provided on the circuit board is inevitable. In addition, when a circuit element is disposed between the choke coil and the circuit board in order to increase the mounting area of the circuit element on the circuit board, the circuit element immediately below the choke coil is forced to receive heat. It was. Alternatively, it is impossible to provide a heat radiation destination for the circuit element, and only heat radiation to the circuit board can be performed.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small electronic circuit device capable of satisfactorily radiating heat from circuit elements to the outside and a rotating electrical machine including the same. .

  In order to solve the above-described problems, an electronic circuit device according to a first aspect of the present invention is provided with a housing, a circuit element provided with the circuit element, and a first heat generation electrically connected to the circuit board. A structural member formed of an element and a member having heat conductivity, to which the first heat generating element is attached, and which is fixed to the housing so that at least a part thereof is disposed between the circuit board and the first heat generating element. And.

According to this configuration, the electronic circuit device is formed of a member having heat conductivity, the first heating element is attached, and at least a part is disposed between the circuit board and the first heating element. A structural member fixed to the housing is provided. Thereby, the heat generated by the first heat generating element is radiated to the housing via the structural member without being directly conducted to the circuit board. Therefore, since it is possible to reduce the influence of heat on the circuit elements attached to the circuit board, it is possible to increase the allowable value of self-heating that allows the circuit elements to operate normally. The structural members in the present invention include those that are fixed directly to the housing and those that are fixed to the housing indirectly without using a circuit board.
In addition, by mounting the first heat generating element on the structural member, it is possible to secure a mounting area for other circuit elements under the structural member on the circuit board, and to reduce the size of the entire electronic circuit device.

  In order to solve the above-described problem, an invention of a rotating electrical machine according to claim 8 is a rotating electrical machine including the electronic circuit device according to any one of claims 1 to 7, wherein the housing is a motor. This is a housing.

  According to this configuration, in the rotating electric machine, heat generated by the first heat generating element is radiated to the motor housing via the structural member without being directly conducted to the circuit board. Therefore, the influence of heat on the circuit elements attached to the circuit board can be reduced, and the rotating electrical machine can operate normally.

1 is a circuit diagram of an electric motor including an inverter circuit according to Embodiment 1 of the present invention. 1 is a cross-sectional view of an electronic circuit device included in the electric motor shown in FIG. Sectional drawing of the electronic circuit device by Embodiment 2 Sectional drawing of the electronic circuit apparatus by Embodiment 3 Sectional drawing of the electronic circuit apparatus by Embodiment 4

  Embodiments 1 to 4 of the present invention will be described below. Hereinafter, the upper direction in FIGS. 2 to 5 is the upper side of the electric motor 1, the lower side in FIGS. 2 to 5 is the lower side of the electric motor 1, and the horizontal direction in FIGS. 2 to 5 is the horizontal direction of the electric motor 1. However, this is independent of the actual mounting direction of the electric motor 1. The electric motor 1 corresponds to a rotating electric machine.

<Configuration of Embodiment 1>
Based on FIG. 1, the circuit configuration of the electric motor 1 according to the first embodiment of the present invention will be described. The electric motor 1 in the present embodiment is formed by a brushless DC motor, but is not limited thereto, and may be a synchronous motor, an induction motor, or other electric motor.
The electric motor 1 includes an inverter circuit 2, a stator 3, a drive circuit 4, a microcomputer 5 (hereinafter referred to as a microcomputer 5), and a rotation angle sensor 6. The inverter circuit 2 corresponds to a power conversion circuit unit.

  The inverter circuit 2 includes a choke coil 21 having one end connected to the positive electrode side of the DC power source 7 and a shunt resistor 22 having one end connected to the negative electrode side of the DC power source 7. The choke coil 21 corresponds to a first heating element. A smoothing capacitor 23 is connected between the other end of the choke coil 21 and the other end of the shunt resistor 22. The choke coil 21 and the smoothing capacitor 23 constitute a noise filter, and reduce the inflow of noise into the electric motor 1 and the outflow of noise from the electric motor 1. Further, the choke coil 21 and the smoothing capacitor 23 smooth the voltage from the DC power source 7 and reduce its pulsation.

  The other end of the choke coil 21 has a three-phase in-side switching element 24i formed by a semiconductor active element such as a metal-oxide-semiconductor field effect-transistor (MOS-FET) or an insulated gate bipolar transistor (IGBT). Drain terminals are connected in parallel. On the other hand, the other end of the shunt resistor 22 is connected in parallel with a source terminal of a three-phase out-side switching element 24o similar to the in-side switching element 24i. The source terminal of the in-side switching element 24i and the drain terminal of the corresponding out-side switching element 24o are connected to each other. Hereinafter, the in-side switching element 24i and the out-side switching element 24o are collectively referred to as a switching element 24.

  Furthermore, the in-side return diode 25i is connected in parallel to the in-side switching element 24i. Further, an out-side reflux diode 25o is connected in parallel to the out-side switching element 24o. Hereinafter, the in-side freewheeling diode 25i and the out-side freewheeling diode 25o are collectively referred to as the freewheeling diode 25.

The stator 3 has three-phase stator coils 3u, 3v, and 3w. One end of each of the stator coils 3u, 3v, 3w is connected to the source terminal of the corresponding in-side switching element 24i, and the other ends are connected to each other. Furthermore, the electric motor 1 includes a rotor (not shown) so as to face the stator 3 in the radial direction.
The drive circuit 4 is connected to each gate terminal of the switching element 24. A microcomputer 5 is connected to the drive circuit 4.

  The microcomputer 5 is connected with a rotation angle sensor 6 formed by an encoder, a resolver, or a Hall IC. The microcomputer 5 generates a control signal based on a value detected by the rotation angle sensor 6 and a current flowing through the shunt resistor 22. And transmitted to the drive circuit 4. The drive circuit 4 forms a PWM (Pulse Width Modulation) signal based on the control signal from the microcomputer 5 and transmits it to the gate terminal of each switching element 24. The switching element 24 performs a switching operation by a PWM signal, converts the voltage of the DC power supply 7 into a required AC voltage, and supplies the AC voltage to the stator coils 3u, 3v, and 3w. Thereby, the rotation of the rotor of the electric motor 1 is controlled by the microcomputer 5.

  The electric motor 1 includes the electronic circuit device 10 shown in FIG. The electronic circuit device 10 includes a motor housing 11 formed of a metal casing having excellent thermal conductivity such as an aluminum alloy. The motor housing 11 corresponds to a housing. Inside the motor housing 11, a circuit component housing portion 11a is formed. A circuit board 12 is fixed to the mounting surface 11b below the motor housing 11 so as to face the circuit component housing portion 11a. The circuit board 12 is attached to the attachment surface 11 b by fastening a plurality of penetrating fastening bolts 13 to the motor housing 11. As shown in FIG. 2, a plurality of circuit elements 14 are mounted on the upper surface 12 a of the circuit board 12. In addition to the circuit element 14, the above-described inverter circuit 2 is mounted on the upper surface 12 a of the circuit board 12, and the drive circuit 4 and the microcomputer 5 are attached to the lower surface 12 b of the circuit board 12.

  A structural member 15 is fixed to the ceiling surface 11a1 of the circuit component housing portion 11a by a plurality of screws 16. The structural member 15 is formed in a substantially U shape by a plate material having heat conductivity such as an aluminum plate. The structural member 15 is attached to the ceiling surface 11a1 by fastening a screw 16 passed through the flange portion 15a at the upper end portion to the motor housing 11. The above-described choke coil 21 is attached to the upper surface of the bottom portion 15 b of the structural member 15, and the lower surface faces the circuit board 12. Thereby, at least the bottom 15 b of the structural member 15 is disposed between the choke coil 21 and the circuit board 12. The structural member 15 surrounds the choke coil 21 in the left-right direction in FIG. 2, but is open in the direction perpendicular to the paper surface in FIG. The structural member 15 may be formed so as to surround the choke coil 21 from four directions.

The choke coil 21 is formed by winding a winding (not shown) around the core 211. In addition, the choke coil 21 is electrically connected to the circuit board 12 by soldering the tip after a plurality of coil terminals 212 are inserted into through holes (not shown) formed in the circuit board 12. It is connected to the. Each coil terminal 212 penetrates the structural member 15 while being insulated. If the choke coil 21 is mounted on the circuit board 12, the area occupied on the circuit board 12 by the choke coil 21 is formed to be larger than the area occupied on the circuit board 12 by one circuit element 14. Yes.
With the configuration described above, heat generated in the choke coil 21 is conducted to the motor housing 11 via the structural member 15 and is radiated to the outside of the electric motor 1 via the motor housing 11.

<Effect of Embodiment 1>
According to the present embodiment, the electric motor 1 is formed of a plate material having heat conductivity, the choke coil 21 is attached to the upper surface of the bottom portion 15 b, and the bottom portion 15 b is disposed between the choke coil 21 and the circuit board 12. Thus, a structural member 15 fixed to the motor housing 11 is provided. Thus, heat generated by the choke coil 21 is radiated to the motor housing 11 via the structural member 15 without being conducted to the circuit board 12. Therefore, even if the circuit element 14 is mounted on the circuit board 12 using the space between the choke coil 21 and the circuit board 12 as shown in FIG. Will not be affected. For this reason, the circuit element 14 can operate | move normally, and the electric motor 1 can operate | move normally by extension.

The choke coil 21 is formed so as to be larger than the area occupied by the circuit element 14 on the circuit board 12 when mounted on the circuit board 12. On the other hand, since the choke coil 21 is attached to the structural member 15 in the present embodiment, the mounting area on the circuit board 12 can be prevented from being reduced by the choke coil 21. Therefore, the mounting area of the circuit element 14 can be secured on the circuit board 12, and the entire electronic circuit device 10 can be reduced in size.
Since the bottom 15b of the structural member 15 can be made closer to the circuit board 12 than the inner peripheral surface of the motor housing 11, the heat generated on the circuit board 12 can be radiated more easily through the structural member 15. be able to.

<Configuration of Embodiment 2>
An electronic circuit device 10A according to Embodiment 2 of the present invention will be described with reference to FIG. In the electronic circuit device 10A, the circuit element 14 includes at least one of the shunt resistor 22, the switching element 24, and the free wheel diode 25 described above. The circuit element 14 corresponds to a second heating element. The circuit element 14 faces the bottom portion 15b of the structural member 15, and a heat conductive member 17 having insulation is interposed between the circuit element 14 and the structural member 15. The heat conductive member 17 is formed of a heat radiating sheet or a heat radiating gel. The heat radiating sheet and the heat radiating gel are disclosed in Japanese Patent Application Laid-Open Nos. 2006-249314 and 2014-138030, which are open patent gazettes. The choke coil 21 according to the present embodiment is formed so that the amount of heat generation is smaller or the heat generation speed is lower than that of the circuit element 14, but is not limited thereto.

  As shown in FIG. 3, the heat generated in the circuit element 14 is conducted to the bottom 15 b of the structural member 15 through the heat conductive member 17. The heat transmitted to the bottom portion 15 b is radiated to the motor housing 11 via the flange portion 15 a of the structural member 15 or the screw 16. The heat conduction path described above is indicated by a broken line in FIG. Since the other configuration of the electronic circuit device 10A is the same as that of the electronic circuit device 10 according to the first embodiment, further description thereof is omitted.

<Effects of Second Embodiment>
According to this embodiment, the circuit element 14 is disposed so as to face the structural member 15, and the heat conductive member 17 is interposed between the circuit element 14 and the structural member 15. As a result, heat generated by the circuit element 14 is conducted to the structural member 15 via the heat conductive member 17 and then radiated to the motor housing 11. Therefore, it can reduce that the heat_generation | fever by the circuit element 14 is transmitted to the other components attached to the circuit board 12, and can operate them normally.

  The electronic circuit device 10 </ b> A has an inverter circuit 2, a noise prevention choke coil 21 included in the inverter circuit 2 is attached to the structural member 15, and the circuit element 14 includes a shunt resistor included in the inverter circuit 2. 22, at least one of the switching element 24 and the freewheeling diode 25 is included. Thereby, in the inverter circuit 2, the occupation of the area on the circuit board 12 by the choke coil 21 can be prevented, and many circuit elements 14 can be mounted on the circuit board 12. Further, the structural member 15 can dissipate heat generated by the choke coil 21 and the circuit element 14 on the circuit board 12 to the motor housing 11, thereby eliminating the influence of heat in the inverter circuit 2 so that the inverter circuit 2 can be normally operated. Can be operated.

  The choke coil 21 according to the present embodiment is formed so that the heat generation amount is smaller than that of the circuit element 14 or the heat generation rate is lower. In this case, heat conduction from the circuit element 14 to the structural member 15 increases on the heat conductive member 17, and the influence of heat conduction from the choke coil 21 to the circuit element 14 is small. Therefore, the heat radiation from the circuit element 14 proceeds, the influence of heat conduction from the choke coil 21 to the circuit element 14 can be reduced, and the circuit element 14 can be effectively radiated.

<Configuration of Embodiment 3>
A structural member 15A according to Embodiment 3 of the present invention will be described with reference to FIG. In the structural member 15A, a pair of vertical walls 15c are connected below the flange portion 15a. A plurality of heat dissipating fins 15d are provided upright on the outer peripheral surface of each vertical wall 15c. Each heat dissipating fin 15d extends in the horizontal direction to increase the outer peripheral area of the structural member 15A, and is formed so that heat conducted from the choke coil 21 and the circuit element 14 can be dissipated into the air. Since the other configuration of the structural member 15A is the same as that of the structural member 15 according to the first embodiment, further description thereof is omitted.

<Effect of Embodiment 3>
According to the present embodiment, the heat radiation from the choke coil 21 and the circuit element 14 can be further increased by providing the heat radiation fins 15d on the outer peripheral surface of the structural member 15A.

<Configuration of Embodiment 4>
Based on FIG. 5, a structural member 15B according to Embodiment 4 of the present invention will be described. In the present embodiment, the core 211 of the choke coil 21 </ b> A includes an iron core 213 and a covering portion 214 that is formed of a synthetic resin material that is an insulating material and covers the periphery of the iron core 213. The covering portion 214 corresponds to a part of the core. The structural member 15B includes a base 151 that is integrally formed with the covering portion 214 using a synthetic resin material, and a heat transfer portion 152 that covers the outer peripheral surface of the base 151 on the side facing the circuit element 14. The heat transfer portion 152 is formed of a metal plate material having excellent heat transfer properties such as aluminum and covers the entire outer peripheral surface of the base portion 151. The heat transfer portion 152 is thermally connected to the motor housing 11 by the screw 16 penetrating the heat transfer flange 152a at the upper end being fastened to the ceiling surface 11a1.

  Heat generated by the circuit element 14 is conducted to the heat transfer section 152 via the heat conductive member 17 and is radiated from the heat transfer flange 152a to the motor housing 11 via the screw 16. The heat conduction path described above is indicated by a broken line in FIG. Since the other configuration of the structural member 15B is the same as that of the structural member 15 according to the first embodiment, further description is omitted.

<Effect of Embodiment 4>
According to the present embodiment, the structural member 15B includes the base 151 formed integrally with the covering portion 214 of the core 211 by an insulating material, and the heat transfer covering the outer peripheral surface of the base 151 on the side facing the circuit element 14. Part 152. Thereby, the base 151 of the structural member 15 </ b> B can be easily formed together with the covering portion 214 of the core 211. Further, the heat transfer section 152 is thermally connected to the motor housing 11. Thereby, the heat generated by the circuit element 14 can be radiated to the motor housing 11 via the heat transfer portion 152.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
The present invention can also be applied to a generator that generates electric power in the stator 3 by rotating the rotor.
The present invention can also be applied to a motor generator having both functions of a generator and a motor.
The structural members 15, 15 </ b> A, and 15 </ b> B in the present invention include those that are fixed directly to the motor housing 11 and those that are fixed to the motor housing 11 indirectly without the circuit board 12. It is out.
Further, the circuit board 12 and the structural member 15 may be attached to the saddle-shaped housing of the electronic control unit instead of the motor housing 11.

  In the drawings, 1 is an electric motor (rotary electric machine), 2 is an inverter circuit (power conversion circuit unit), 10 and 10A are electronic circuit devices, 11 is a motor housing (housing), 12 is a circuit board, 14 is a circuit element, 15 , 15A and 15B are structural members, 15d is a heat radiation fin, 17 is a heat conductive member, 21 and 21A are choke coils (first heating elements), 22 is a shunt resistor (second heating element), and 24 is a switching element ( MOS-FET, second heating element, semiconductor active element), 25 is a free-wheeling diode (second heating element), 151 is a base, 152 is a heat transfer part, 211 is a core, 214 is a covering part (a part of the core) Show.

Claims (8)

A housing (11);
A circuit board (12) provided with a circuit element (14) and attached to the housing;
A first heating element (21, 21A) electrically connected to the circuit board;
A structure formed of a member having heat conductivity and fixed to the housing so that the first heat generating element is attached and at least a part thereof is disposed between the circuit board and the first heat generating element. Members (15, 15A, 15B);
An electronic circuit device (10, 10A).   The occupying area on the circuit board when the first heating element is mounted on the circuit board is formed to be larger than an occupying area on the circuit board by the circuit element. Electronic circuit device. The circuit element includes a second heating element (22, 24, 25) arranged to face the structural member,
The electronic circuit device according to claim 1 or 2, wherein a heat conductive member (17) is interposed between the second heating element and the structural member.   4. The electronic circuit device according to claim 3, wherein the first heat generating element is formed to have a smaller heat generation amount or a lower heat generation rate than the second heat generating element. 5. A power conversion circuit unit (2), wherein the first heating element is a choke coil (21, 21A) for noise reduction included in the power conversion circuit unit;
The choke coil (21A) has a core (211) around which a winding is wound,
The structural member (15B) includes a base (151) formed integrally with at least a part (214) of the core by an insulating material, and a heat that covers the outer peripheral surface of the base facing the circuit element. Transmission part (152),
The electronic circuit device according to claim 3, wherein the heat transfer section is thermally connected to the housing.   6. The electronic circuit device according to claim 5, wherein the second heating element is at least one of a semiconductor active element (24), a shunt resistor (22), and a free-wheeling diode (25) included in the power conversion circuit unit. .   The electronic circuit device according to any one of claims 1 to 4, wherein a heat radiating fin (15d) is erected on an outer peripheral surface of the structural member (15A).   A rotating electrical machine (1) comprising the electronic circuit device according to any one of claims 1 to 7, wherein the housing is a motor housing (11).

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