JP2015171252A - Electric power conversion system and electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power conversion system which achieves high thermal reliability.SOLUTION: An electric power conversion system includes: a wiring board 23 on which multiple electronic components 24 forming a power conversion circuit are mounted on at least a first mounting surface 23x; a housing 21 which stores the wiring board 23 in a storage part 22 enclosed by a bottom part 21a and a side wall part 21b; multiple first support mediums 26 which support a periphery part of the wiring board 23 in a state where the first mounting surface 23x of the wiring board 23 faces the bottom part 21a of the housing 21 and the wiring board 23 is separated from the bottom part 21a and the side wall part 21b of the housing 21; and a second support medium 30 which supports the wiring board 23 at the inner side of the wiring board 23 relative to the multiple first support mediums 26 and is provided with a passage 31 which communicates with a second space region 22b at a second mounting surface 23y side of the wiring board 23 through a through hole 23a formed on the wiring board 23 and a first space region 22a at the first surface 23x side.

Description

  The present invention relates to a power conversion device and an electric motor, and in particular, is applied to a power conversion device that houses a wiring board on which a plurality of electronic components constituting a power conversion circuit are mounted, and an electric motor including the same. It relates to effective technology.

As an electric motor used as a drive source for various devices, an electric motor including a power converter is known. Patent Document 1 discloses an inverter-integrated AC motor in which an inverter module as a power converter is integrated. Further, Patent Document 2 discloses a housing for incorporating a substrate that can be applied to a power conversion device integrated with an electric motor.
This board built-in casing is formed by connecting a plurality of wiring boards in a casing formed by connecting two casing parts each having a U-shaped cross section so that each opening faces each other. It is structured to be stored at a predetermined interval in the thickness direction. And each wiring board is being fixed to the mounting seat from which the peripheral part protrudes inside the housing | casing from the side wall part of a housing | casing. Each wiring board is mounted with a heat generating electronic component on each of the first and second mounting surfaces located on opposite sides in the thickness direction. The heat released from the electronic component is transmitted to the casing by natural convection and is dissipated from the casing to the outside.

JP 2007-116840 A JP 2012-227399 A

However, the substrate built-in housing disclosed in Patent Document 2 has the following problems.
That is, in the case with a substrate built-in disclosed in Patent Document 2, since the peripheral portion of the wiring substrate is fixed to a mounting seat (support) that protrudes inward from the side wall portion of the housing, the thickness of the wiring substrate Spatial regions exist on the first and second mounting surface sides that are opposite to each other in the direction.

On the other hand, although not described in detail in Patent Document 2, in a structure in which a wiring board is stored in a storage part surrounded by a bottom part and a side wall part of the casing, the wiring board and the side wall part of the casing are generally provided. A gap is provided between them.
Here, when each of the first and second mounting surfaces of the wiring board is located on the opposite side in the direction of gravity, the first mounting surface is the lower surface with respect to the direction of gravity, and the second mounting surface is When the upper surface is used, the heat generated by the heat generated by the electronic components mounted on the lower surface (first mounting surface) of the wiring board is accumulated near the surface of the lower surface of the wiring board.

Of the hot air accumulated near the surface of the lower surface of the wiring board, the hot air at the peripheral edge of the wiring board passes through the gap between the wiring board and the side wall of the housing, and the space area and upper surface on the lower surface side of the wiring board. Natural convection (exhaust of hot air and inflow of cold air) occurs over the space area on the (second mounting surface) side, so that it does not stay.
However, active natural convection cannot be expected for the hot air at the center of the wiring board because the distance to the gap between the wiring board and the side wall of the housing is long.

  For this reason, hot air accumulates in the central portion on the lower surface side of the wiring board, and the internal air temperature on the lower surface side of the wiring board rises due to further heat generation of the electronic components. As a result, the inside air temperature exceeds the allowable temperature of the electronic component, which causes a problem that the performance of the electronic component is significantly deteriorated. This failure means a decrease in reliability of the power converter and the electric motor including the power converter.

In particular, in a power conversion device, a plurality of electronic components constituting a power conversion circuit are mounted on a wiring board. Among the plurality of electronic components, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field). Power components equipped with switching elements consisting of power transistors such as Effect Transistor) are included. Since this power component handles a large amount of power and generates a large amount of heat, it is important to improve the reliability of heat.
Therefore, the present inventor made the present invention by paying attention to a support for supporting the wiring board.
The objective of this invention is providing the power converter device with high reliability with respect to a heat | fever, and an electric motor provided with the same.

  In order to achieve the above object, a power conversion device according to an aspect of the present invention includes first and second surfaces positioned on opposite sides, and a plurality of electronic components constituting a power conversion circuit are at least the first. A wiring board mounted on one surface, a housing for housing the wiring board in a housing portion surrounded by a bottom and a side wall, the first surface of the wiring board facing the bottom, and A plurality of first supports that support a peripheral portion of the wiring board in a state in which the wiring board is spaced apart from the bottom and side walls; and the wiring board inside the wiring board than the plurality of first supports. And communicates with the second space region on the second surface side of the wiring substrate and through the first space region on the first surface side through a through hole formed in the wiring substrate. And a second support provided with a flow path. It is set to.

Further, in the power conversion device according to one aspect of the present invention, the second support body is configured by a plurality of protrusions that protrude from the bottom portion toward the wiring substrate and that surround the flow path. Preferably it is.
Further, in the power conversion device according to one aspect of the present invention, the second support body has an insertion portion to be inserted into the through hole on one end side on the wiring board side, and the insertion portion is a stepped portion. It is preferable that it is comprised by the part and the protrusion piece which protrudes from the said step part.

In the power conversion device according to one aspect of the present invention, it is preferable that the second support body has a board fastening and fixing portion to which the wiring board is fastened and fixed by a fastening member.
Furthermore, an electric motor according to an aspect of the present invention includes any one of the above-described power conversion devices.

  ADVANTAGE OF THE INVENTION According to this invention, the reliable power converter device with respect to a heat | fever and an electric motor provided with the same can be provided.

It is sectional drawing which shows schematic structure of the electric motor provided with the inverter which concerns on one Embodiment of this invention. It is a top view of the electric motor of FIG. It is a bottom view of the electric motor of FIG. It is a top view of the inverter of FIG. It is sectional drawing which shows the cross-sectional structure along the AA line of FIG. It is a perspective view which extracts and shows the inverter housing | casing of FIG. It is sectional drawing which shows the cross-sectional structure along the BB line of FIG. In the inverter of FIG. 1, it is the figure ((a) top view, (b) is sectional drawing) which showed the convection state of the hot air with the arrow.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments of the invention, and the repetitive description thereof is omitted.
As shown in FIGS. 1 to 3, the electric motor 1 according to the present embodiment is an inverter-integrated electric motor including a motor unit 10a and an inverter unit 10b.

  The motor unit 10 a includes a motor housing 11 and a rotor core 12 and a magnet 13 housed in the housing portion of the motor housing 11. The motor unit 10a includes a shaft 14 that is supported on the motor casing 11 via two bearings 15 and 16 that extend in and out of the motor casing 11 and that are separated from each other in the axial direction. Yes. The motor unit 10 a is configured to transmit the rotational force obtained from the rotor core 12 and the magnet 13 to the outside through the shaft 14.

The motor housing 11 has a circular cylindrical shape and is made of a metal material. A plurality of convex fins 17 are provided radially on the outside of the side wall portion of the motor housing 11 for cooling the motor portion 10a with outside air.
An inverter 20 as a power conversion device is mounted on the inverter unit 10b. The inverter 20 includes a power conversion circuit that converts power from DC to AC and supplies the power to the motor unit 10a. The inverter 20 also includes a control circuit that controls operations such as the rotational speed and torque of the shaft 14 of the motor unit 10a.

  As shown in FIGS. 1, 4, and 5, the inverter 20 includes a wiring board 23 and an inverter housing 21 as a housing for housing the wiring board 23. The inverter housing 21 includes a bottom portion 21a and a side wall portion 21b, a storage portion 22 surrounded by the bottom portion 21a and the side wall portion 21b, and an opening provided on the side opposite to the bottom portion 21a. The inverter casing 21 has a circular cylindrical shape and is made of a metal material, like the motor casing 11. That is, the storage unit 22 is formed in a circular planar shape.

  The inverter housing 21 includes a seal portion 21c on the opening side of the side wall portion 21b. The seal portion 21c is provided with a rubber-like O-ring 28 along the outer periphery of the inverter housing 21 on the outer wall of the side wall portion. The seal portion 21 c is inserted into the opening of the motor housing 11. That is, the motor casing 11 and the inverter casing 21 are connected in series by inserting the seal portion 21c of the inverter casing 21 into the opening of the motor casing 11, and the connecting portion of both is watertight by the seal portion 21c. It becomes a structure. For this reason, the storage part of the motor housing | casing 11 and the storage part 22 of the inverter housing | casing 21 will be in a sealed state. In addition, the inverter housing 21 is connected to the motor housing 11 so that the storage portion 22 is surrounded by the motor housing 11 together with the bottom portion 21a and the side wall portion 21b.

  The wiring substrate 23 has first and second mounting surfaces 23x and 23y located on opposite sides in the thickness direction. Further, the planar shape of the wiring board 23 is formed in a circular shape in accordance with the planar shape of the storage portion 22 of the inverter housing 21. The wiring board 23 is formed in a plane size smaller than the plane size of the storage portion 22 of the inverter housing 21. This is because a gap 40 is provided between the wiring board 23 and the side wall 21b of the inverter housing 21 as described later. The wiring board 23 has a configuration in which a wiring pattern is formed on the front and back surfaces of a base material made of a resin such as glass epoxy.

  A plurality of electronic components 24 and 25 constituting a power conversion circuit and a control circuit are mounted on the first and second mounting surfaces 23x and 23y of the wiring board 23, respectively. The plurality of electronic components 24 mounted on the first mounting surface 23x of the wiring board 23 includes large electronic components such as diodes and electric field capacitors that generate a large amount of heat. In addition, the plurality of electronic components 24 includes a power module 24a on which a switching element made of a power transistor such as an IGBT or a MOSFET is mounted. The power module 24a is large in size because it handles a large amount of power and generates a large amount of heat.

  The inverter housing 21 includes a plurality of first supports 26 that support the peripheral edge of the wiring board 23. In the present embodiment, four first supports 26 are provided. Each of the four first supports 26 is formed so as to protrude from the side wall portion 21b of the inverter housing 21 to the inside of the side wall portion 21b, and has a board fixing portion to which the wiring board 23 is fixed. . Each of the four first supports 26 is arranged at a position shifted 90 ° clockwise around the center of the inverter housing 21 when the inverter housing 21 is viewed in plan. That is, each of the four first supports 26 is arranged in two straight lines that pass orthogonally through the center of the inverter housing 21. Each of the four first supports 26 is formed integrally with, for example, the bottom 21 a and the side wall 21 b of the inverter housing 21.

  The wiring board 23 is housed in the housing portion 22 of the inverter housing 21 in a state of being supported by the plurality of first support bodies 26. Specifically, the wiring board 23 has four first mounting surfaces 23x in a state where the first mounting surface 23x faces the bottom 21a of the inverter housing 21 and is separated from the bottom 21a and the side wall 21b of the inverter housing 21. The support 26 is supported. The peripheral edge of the wiring board 23 is fastened and fixed to the board fixing parts of the four first supports 26 by fastening members 42.

A gap 40 is provided between the wiring board 23 and the side wall 21 b of the inverter housing 21. The gap 40 is formed in an annular shape along the outer periphery of the wiring board 23.
The storage unit 22 of the inverter housing 21 stores the wiring board 23, thereby the first space region 22 a on the first mounting surface 23 x side of the wiring board 23 with the wiring board 23 as a boundary, and the wiring board 23. It is divided into a second space region 22b on the second mounting surface 23y side. The first space region 22 a is surrounded mainly by the bottom 21 a and the side wall 21 b of the inverter housing 21 and the wiring board 23. Since the inverter housing 21 is connected in series to the motor housing 11 in the second space region 22a, the side wall portion 21b of the inverter housing 21, the wiring board 23, and the motor housing 11 are mainly used. Surrounded.

  The inverter housing 21 supports the wiring board 23 inside the wiring board 23 rather than the plurality of first supports 26, and the second mounting surface of the wiring board 23 through the through holes 23 a formed in the wiring board 23. The second support 30 is provided with a flow path 31 that communicates with the second space region 22b on the 23y side and communicates with the first space region 22a on the first mounting surface 23x side of the wiring board 23. ing.

In the present embodiment, one second support 30 is arranged at the position of the central portion that overlaps the center of the wiring substrate 23 when viewed in plan, in other words, at the central portion of the storage portion 22 of the inverter housing 21. Yes.
In the present embodiment, the second support 30 protrudes from the bottom 21a of the inverter housing 21 toward the wiring board 23 as shown in FIGS. A plurality of protrusions 32 are arranged so as to be spaced apart from each other. The second support body 30 of this embodiment is composed of three protrusions 32. The flow path 31 includes a region surrounded by the protrusions 32 and openings between the three protrusions 32. Each of the three protrusions 32 is formed integrally with the bottom portion 21a of the inverter housing 21, for example.

  The second support 30 has an insertion portion 33 that is inserted into the through hole 23 a of the wiring board 23 on one end side on the wiring board 23 side. The insertion portion 33 includes a step portion 34 and a protruding piece 35 protruding from the step portion 34, and is inserted into the through hole 23 a of the wiring board 23. When the wiring board 23 is stored in the storage part 22 of the inverter housing 21, the insertion part 33 is inserted into the through hole 23 a of the wiring board 23, thereby positioning the wiring board 23.

The second support 30 has a substrate fastening and fixing part 36. The wiring board 23 is fastened and fixed to the board fastening and fixing portion 36 by a fastening member 43. The board fastening and fixing portion 36 is formed integrally with one of the three protrusions 32.
A plurality of convex fins 27 are provided radially on the outside of the side wall portion 21b of the inverter housing 21 for cooling the inverter portion 10b with outside air.

  The housing portion 22 of the inverter housing 21 is provided with a component fixing portion 29 (see FIG. 6) that protrudes inward from the side wall portion 21b of the inverter housing 21. The component fixing portion 29 is formed integrally with the bottom portion 21 a and the side wall portion 21 b of the inverter housing 21. Among the electronic components 24 mounted on the first mounting surface 23x of the wiring board 23, for example, a power module 24a having a high calorific value is fastened and fixed to the component fixing portion 29 by a fastening member.

Note that the inverter 20 of the present embodiment is not illustrated, but a cable that transmits power supply and control signals from the outside to the wiring board 23, a joint that inserts this cable into the inverter housing 21 and maintains watertightness, A cable for transferring power supply and control signals from the inverter unit 10b to the motor unit 10a is also provided.
Moreover, as the fastening members 42 and 43, the member which combined the volt | bolt and the nut, or a screw member can be used.

Next, hot air convection in the inverter 20 of the present embodiment will be described with reference to FIG.
When each of the first and second mounting surfaces 23x and 23y of the wiring board 23 is located on the opposite side with respect to the direction of gravity, the first mounting surface 23x is a lower surface, and the second mounting surface 23y is an upper surface. Then, the hot air generated by the heat generated by the electronic component 24 mounted on the first mounting surface 23x (lower surface) of the wiring board 23 is accumulated near the surface of the first mounting surface 23x of the wiring board 23.

  Of the hot air accumulated near the surface of the first mounting surface 23 x of the wiring board 23, the hot air near the peripheral edge of the wiring board 23 is a gap between the wiring board 23 and the side wall 21 b of the inverter housing 21. 40, since natural convection occurs between the first space region 22a on the first mounting surface 23x side of the wiring board 23 and the second space region 22b on the second mounting surface 23y side, the wiring board 23 does not stay. .

  On the other hand, among the hot air accumulated near the surface of the first mounting surface 23 x of the wiring board 23, the hot air near the center of the wiring board 23 is a gap between the wiring board 23 and the side wall portion 21 b of the inverter housing 21. Although the distance to the portion 40 is long, in the inverter 20 of the present embodiment, the second support body that supports the central portion of the wiring board 23 inside the wiring board 23 rather than the gap portion 40 and the four first support bodies 26. 30, the second support 30 communicates with the second space region 22b on the second mounting surface 23y side of the wiring board 23, and the first space on the first mounting surface 23x side. Since the flow path 31 communicating with the region 22a is provided, even in the hot air near the center of the wiring board 23, the first mounting surface 23x side of the wiring board 23 passes through the flow path 31 of the second support 30. First space region 22a and second mounting It does not remain because the natural convection occurs over a second spatial region 22b of 23y side. That is, the flow path that connects the first space region 22a on the first mounting surface 23x side of the wiring substrate 23 and the second space region 22b on the second mounting surface 23y side in the vicinity of the center of the wiring substrate 23. 31 is formed, natural convection is activated, and heat convection is improved. As a result, it is possible to suppress an increase in the inside air temperature on the first mounting surface 23x side of the wiring board 23, the inside air temperature exceeds the allowable temperature of the electronic component 24, and the performance of the electronic component 24 is significantly degraded. Therefore, the reliability with respect to the heat | fever of the inverter 20 and the electric motor 1 provided with this inverter 20 can be improved.

  Here, the conventional structure will be described with reference to the drawings of the present embodiment. In the conventional structure in which only the peripheral portion of the wiring board 23 is supported and fixed to the first support body 26 of the inverter housing 21, When receiving the vibration, the central portion of the wiring board 23 far from the first support 26 greatly vibrates (resonates). In particular, when a capacitor or a power module 24a, which is relatively heavy as an electronic component, is mounted at the center of the wiring board 23, vibration becomes significant. Due to this vibration, an electronic component mounted with solder near the center of the wiring board 23 may be repeatedly shaken to cause problems such as solder cracks and lead cutting.

  On the other hand, in the inverter 20 of this embodiment, since the center part of the wiring board 23 that is weakest against vibration is supported by the second support 30, the vibration of the wiring board 23 can be reduced. Further, in the inverter 20 of the present embodiment, since the central portion of the wiring board 23 is fastened and fixed to the board fastening and fixing portion 36 of the second support 30 by the fastening member 43, the vibration of the wiring board 23 is further reduced. be able to. As a result, it is possible to suppress problems such as solder cracks and lead cutting that occur when electronic components mounted with solder near the center of the wiring board 23 are repeatedly shaken, so that the inverter 20 and the electric motor including the inverter 20 can be suppressed. The quality of the motor 1 can be improved.

In the inverter 20 of the present embodiment, the insertion portion 33 to be inserted into the through hole 23a of the wiring board 23 is provided on one end side of the second support 30, so that the wiring is connected to the storage portion 22 of the inverter housing 21. When the board | substrate 23 is accommodated, the wiring board 23 can be positioned easily, and the fastening process which fastens and fixes the wiring board 23 with a fastening member after that can be performed easily.
In the above-described embodiment, the case where each of the first and second mounting surfaces 23x and 23y of the wiring board 23 is located on the opposite sides with respect to the direction of gravity has been described. Even when each of the second mounting surfaces 23x and 23y is located on the opposite side to the direction orthogonal to the direction of gravity, the provision of the second support body 30 activates the natural body flow and heats the air. Therefore, the reliability of the inverter 20 and the electric motor 1 including the inverter 20 with respect to heat can be improved.

In the above-described embodiment, the case where the central portion of the wiring board 23 is supported by the second support 30 has been described. However, the present invention is not limited to this and is more than the first support 26. The effect can be obtained if it is inside the wiring board 23.
In the above-described embodiment, the case where one second support 30 is provided has been described. However, the present invention is not limited to this, and two or more second supports 30 may be provided.

In the above-described embodiment, the case where the second support 30 is configured by the three protrusions 32 that are separated from each other has been described. However, the present invention is not limited to this, and the two protrusions that are adjacent to each other are not limited thereto. A part may be connected.
In the above-described embodiment, the case where the wiring substrate 23 having a circular planar shape is used has been described. However, the present invention is not limited to this, and for example, the wiring substrate having a rectangular or polygonal planar shape. May be used.

  In the above-described embodiment, the case where the electronic components 24 and 25 are mounted on the first and second mounting surfaces 23x and 23y located on the opposite sides of the wiring board 23 has been described. The electronic component 24 may be mounted on at least one mounting surface of the wiring board 23, that is, the first mounting surface 23 x on the side facing the bottom portion 21 a of the inverter housing 21.

As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.
As described above, the power conversion device and the electric motor according to the present invention have an effect of improving reliability with respect to heat, and a wiring board on which a plurality of electronic components constituting the power conversion circuit are mounted. The present invention is useful for a power conversion device housed in a housing and an electric motor including the power conversion device.

DESCRIPTION OF SYMBOLS 1 ... Electric motor 10a ... Motor part, 10b ... Inverter part, 11 ... Motor housing, 12 ... Rotor core, 13 ... Magnet, 14 ... Shaft, 15, 16 bearing, 17 ... Convex fin 20 ... Inverter (power converter) 21 inverter housing, 21a ... bottom, 21b ... side wall, 22 ... storage, 22a ... first space region, 22b ... second space region 23 ... wiring board, 23a ... through hole, 23x ... first Mounting surface (lower surface), 23y ... second mounting surface (upper surface), 24 ... electronic component, 25 ... electronic component, 26 ... first support, 27 ... convex fin 30 ... second support, 31 ... Flow path, 32 ... projection, 33 ... insertion part, 34 ... step part, 35 ... projection piece, 36 ... substrate fastening fixing part, 37 ... fastening member,
40: Gap part, 42, 43 ... Fastening member

Claims (5)

A wiring board having first and second surfaces located on opposite sides of each other, and a plurality of electronic components constituting a power conversion circuit mounted on at least the first surface;
A housing for housing the wiring board in a housing part surrounded by a bottom part and a side wall part;
A plurality of first supports that support a peripheral portion of the wiring substrate in a state in which the first surface of the wiring substrate faces the bottom and the wiring substrate is separated from the bottom and the side wall;
A second space region on the second surface side of the wiring board through the through-hole formed in the wiring board and supporting the wiring board inside the wiring board from the plurality of first supports. And a second support body provided with a flow path communicating with the first space region on the first surface side. The power conversion device according to claim 1,
The second support body is constituted by a plurality of protrusions that protrude from the bottom portion toward the wiring substrate and are disposed so as to surround the flow path. The power conversion device according to claim 1 or 2,
The second support has an insertion portion to be inserted into the through hole on one end side on the wiring board side,
The power conversion device according to claim 1, wherein the insertion portion includes a step portion and a protruding piece protruding from the step portion. The power conversion device according to any one of claims 1 to 3,
The power converter according to claim 2, wherein the second support includes a board fastening and fixing portion to which the wiring board is fastened and fixed by a fastening member.   An electric motor comprising the power conversion device according to any one of claims 1 to 4.

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