Electronic device and electric drive device including this electronic equipment

Abstract

An electronic device (50) is configured such that, on a first main surface (20U) on a first direction side in a thickness direction of a heat sink (20), a first heating body (1) is disposed; a first heat transfer member (30A) is disposed on a second main surface (20D) of the heat sink (20), which is a rear surface of the first main surface (20U); the first heat transfer member (30A) has a first extension part (30AO) extending outward from an outer edge of the heat sink (20); a second heating body (2) is disposed on a surface on the first direction side of the first extension part (30AO); and the first heating body (1) and the second heating body (2) are thermally insulated from each other.

Description

Electronic device and electric drive device equipped with the electronic device

[0001] The present disclosure relates to an electronic device and an electric drive device equipped with the electronic device.

[0002] Power conversion devices, which are electronic devices installed in hybrid vehicles, electric vehicles, and the like, are required to be smaller and have higher output. The components of power conversion devices handle larger currents as output power increases, resulting in increased heat generation. Even in such cases, there is a demand for compact power conversion devices that can efficiently and rapidly dissipate the heat generated in each component. Conventionally, electronic devices with the following configuration have been disclosed as electronic devices capable of efficiently dissipating heat generated in the components, in which two heat-generating elements are cooled using heat pipes.

[0003] That is, a conventional electronic device includes a housing, first and second heat generating elements arranged with a step between their surfaces, and a cooling module that absorbs heat generated by the first and second heat generating elements. The cooling module includes a first heat pipe having a first surface connected to the surface of the first heat generating element, a plate-shaped vapor chamber having a first surface connected to the surface of the second heat generating element and a second surface of the first heat pipe, a second heat pipe connected to the second surface of the vapor chamber and overlapping the second heat generating element, a first fin connected to the first heat pipe, and a second fin connected to the second heat pipe (see, for example, Patent Document 1).

[0004] JP 2023-92048 A

[0005] However, in the electronic device described above, because a heat conduction path exists between the first and second heating elements via a vapor chamber and a heat pipe, heat is transferred between the first and second heating elements. This causes a problem that heat cannot be efficiently dissipated, and in order to ensure the necessary cooling capacity, it is sometimes impossible to miniaturize the device. The present disclosure discloses a technique for solving the above problem, and aims to provide a compact electronic device that can efficiently dissipate heat generated by a heating element, and an electric drive device equipped with this electronic device.

[0006] According to the electronic device of the present disclosure, there is provided an electronic device comprising a heat generating element, a heat transfer member for transferring heat from the heat generating element, and a heat sink for dissipating heat from the heat generating element, wherein a first heat generating element is disposed on a first main surface on a first direction side in the thickness direction of the heat sink, and a first heat transfer member is disposed on a second main surface of the heat sink which is the back side of the first main surface, and the first heat transfer member has a first extension portion extending outward from the outer edge of the heat sink, and a second heat generating element is disposed on the surface on the first direction side of the first extension portion, so that the first heat generating element and the second heat generating element are thermally insulated from each other. Furthermore, according to the electric drive device equipped with the electronic device of the present disclosure, the electric drive device houses, in an enclosure, an electronic device configured as described above, a motor driven by the electronic device, and an oil cooler that cools the working oil flowing in the motor with a refrigerant, wherein a first wall surface on the first direction side of the enclosure is configured to have the first heat transfer member of the electronic device, and the first heat transfer member is configured to be attached to a flow path through which the refrigerant of the oil cooler flows, so that heat exchange occurs between the first heat transfer member and the refrigerant.

[0007] According to the electronic device of the present disclosure, it is possible to obtain a compact electronic device while efficiently dissipating heat generated in a heat generating element, and also to obtain a compact electric drive device while efficiently dissipating heat generated in a heat generating element and a motor.

[0008] Fig. 1 is a side view showing a schematic configuration of a power conversion device according to embodiment 1. Fig. 2 is a side view showing a schematic configuration of a power conversion device according to embodiment 2. Fig. 3 is a side view showing a schematic configuration of a power conversion device according to embodiment 3. Fig. 4 is a top view showing a schematic configuration of a power conversion device according to embodiment 3. Fig. 5 is a side view showing a schematic configuration of a power conversion device according to embodiment 4. Fig. 6 is a side view showing a schematic configuration of an electric drive device according to embodiment 5.

[0009] Embodiment 1. Figure 1 is a side view showing the schematic configuration of a power conversion device 50 according to embodiment 1. The power conversion device 50 as an electronic device is configured to have a plurality of heat generating elements such as inverters and capacitors, and as shown in Figure 1, in this embodiment, the power conversion device 50 includes a first heat generating element 1, a second heat generating element 2, and a cooling unit 40 that cools the first heat generating element 1 and the second heat generating element 2. The first heat generating element 1 is configured so that its length in the height direction Z is shorter than the length in the height direction Z of the second heat generating element 2.

[0010] The cooling unit 40 includes a heat sink 20 that dissipates heat generated in the first heating element 1 and the second heating element 2, and a heat transfer member 30 that transfers heat received from the first heating element 1 and the second heating element 2 to the heat sink 20. In the drawings, the thickness direction of the heat sink 20 is referred to as the height direction Z, the side to which the arrow points in this height direction Z is referred to as the upward direction Z+ as a first direction, and the opposite side is referred to as the downward direction Z- as a second direction. The horizontal direction of the paper in FIG. 1 , which is perpendicular to the height direction Z, is referred to as the X direction, and the direction perpendicular to the X direction and the Z direction is referred to as the Y direction. In the following description, a plane including the X direction and the Y direction may be referred to as the XY plane.

[0011] The heat sink 20 is formed to have a thermal resistance capable of dissipating heat generated in the first heating element 1 and the second heating element 2, based on the heat generation amounts in the first heating element 1 and the second heating element 2 and the thermal resistance from the first heating element 1 and the second heating element 2 to the heat sink 20. In this embodiment, the heat transfer member 30 includes two members, a first heat transfer member 30A and a second heat transfer member 30B. The heat transfer member 30 is preferably a heat pipe in which a working fluid is sealed in a material with high thermal conductivity, and is configured to have a thermal conductivity higher than that of the heat sink 20.

[0012] The second heat transfer member 30B is disposed within the range of an upper surface 20U serving as a first main surface on the upward Z+ side of the heat sink 20. The first heat transfer member 30A is disposed on the side of a lower surface 20D serving as a second main surface of the heat sink 20, which is the backside of the upper surface 20U of the heat sink 20. This first heat transfer member 30A forms a first extension portion 30AO extending outward from the outer edge of the heat sink 20 in the XY plane perpendicular to the height direction Z. A second heating element 2 serving as a heating element is disposed on the surface of this first extension portion 30AO on the upward Z+ side.

[0013] The first heat transfer member 30A and the second heat transfer member 30B are configured independently of each other, and therefore are thermally independent of each other and attached to the heat sink 20. In this way, the heat sink 20 is interposed in the heat conduction path between the first heating element 1 and the second heating element 2, and the first heating element 1 and the second heating element 2 are thermally insulated from each other.

[0014] According to the cooling structure of the power conversion device 50 configured in this manner, the heat generated in the first heat generating element 1 is transferred to the second heat transfer member 30B and dissipated through the heat sink 20. In addition, the heat generated in the second heat generating element 2 is transferred to the first extension portion 30AO of the first heat transfer member 30A and dissipated through the heat sink 20.

[0015] Since the two heating elements, the first heating element 1 and the second heating element 2, are thermally insulated from each other, there is no heat transfer between the two heating elements, and the maximum heat generation temperature of the heating elements can be reduced compared to when heat is transferred between the heating elements. This allows the heating elements to be made smaller, and also reduces the required cooling capacity of the heat sink 20, making it possible to make the heat sink 20 smaller. In this way, the first heating element 1 and the second heating element 2 can be cooled sufficiently without exceeding the required size range of the cooling unit 40.

[0016] The two heating elements of different heights are arranged in XY planes of different heights in the height direction Z, namely, an XY plane including the upper surface 20U of the heat sink 20 and an XY plane including the lower surface 20D. That is, the first heating element 1, which is shorter, is arranged on the XY plane including the upper surface 20U of the heat sink 20, which is located at a higher position in the height direction Z, and the second heating element 2, which is taller, is arranged on the XY plane including the first extension portion 30AO, which is located at a lower position in the height direction Z. This enables the power conversion device 50 to be made lower in height.

[0017] Preferably, the heat sink 20 has fins made of an aluminum alloy, etc. In order to appropriately cool the heat generating elements of the power conversion device 50, the heat sink 20 may be water-cooled by circulating water, or air-cooled by using fins, etc.

[0018] Preferably, the maximum heat generation amount of the first heating element 1 is greater than the maximum heat generation amount of the second heating element 2. The first heating element 1 is a power semiconductor module such as an inverter including a semiconductor switching element that converts DC power from the power conversion device 50 into AC power, and the second heating element 2 is a capacitor element that smooths the DC voltage supplied to the power conversion device 50, or a resistive element for discharging the charge stored in the capacitor. The first heating element 1 and the second heating element 2 are not limited to the components listed above, and may be any component that constitutes an electronic device as long as it is a heat generating heating element.

[0019] Although the heat transfer member 30 is described as a heat pipe, it is not limited to this and may be made of, for example, a metal with excellent thermal conductivity, highly thermally conductive graphite, etc. The heat pipe may be attached to the heat sink 20 so as to be in surface contact with the heat sink 20, or may be embedded in the heat sink 20 and be in contact with the heat sink 20.

[0020] Furthermore, although an example has been shown in which one first heating element 1 and one second heating element 2 are provided, this is not limited to this, and a configuration having multiple first heating elements 1 or multiple second heating elements 2 may also be used.

[0021] When a plurality of first heating elements 1 are provided, each first heating element 1 is disposed on an independent second heat transfer member 30B. With this configuration, heat generated in the plurality of first heating elements 1 is transferred to the heat sink 20 via the thermally independent second heat transfer members 30B. Therefore, direct heat transfer between the plurality of first heating elements 1 does not occur, enabling efficient heat dissipation.

[0022] Furthermore, when a plurality of second heating elements 2 are provided, the heat sink 20 is configured to have a plurality of first extension portions 30AO extending outward from the outer edge thereof, and a second heating element 2 is disposed on each of these first extension portions 30AO. With this configuration, heat generated in each second heating element 2 is transferred to the heat sink 20 via each thermally independent first extension portion 30AO. Therefore, no heat transfer occurs between the second heating elements 2, enabling efficient heat dissipation.

[0023] The electronic device configured as described above is an electronic device comprising a heat generating element, a heat transfer member that transfers heat from the heat generating element, and a heat sink that dissipates heat from the heat generating element, wherein a first heat generating element is disposed on a first main surface on a first direction side in the thickness direction of the heat sink, and a first heat transfer member is disposed on a second main surface of the heat sink that is the back side of the first main surface, and the first heat transfer member has a first extension portion that extends outward from the outer edge of the heat sink, and a second heat generating element is disposed on the surface on the first direction side of the first extension portion, so that the first heat generating element and the second heat generating element are thermally insulated from each other.

[0024] In this configuration, a first heating element is disposed on the first main surface of the heat sink, a first heat transfer member is disposed on the upper surface of the second main surface of the heat sink, and a second heating element is disposed on a first extension portion of the first heat transfer member that extends outward from the outer edge of the heat sink. This thermally insulates the first heating element from the second heating element, ensuring that no heat is transferred between the first heating element and the second heating element, while allowing the heat generated by each heating element to be efficiently dissipated through the heat sink. This reduces the maximum heat generation temperature of the heating element and allows the heat sink to be made smaller, making it possible to provide a compact electronic device.

[0025] Furthermore, since the heat sink can be made smaller, the components that make up electronic devices such as power converters can be arranged close to each other, ensuring performance through low parasitic inductance and low resistance.Furthermore, it is possible to improve the design freedom for the relative positions of the first heating element 1 and the second heating element 2.

[0026] In the electronic device configured as described above, the maximum heat generation amount of the first heat generating element is larger than the maximum heat generation amount of the second heat generating element.

[0027] In this way, by placing the first heating element, which is a high heat-generating component, on the first main surface side of the heat sink, a necessary and sufficient contact area between the first main surface and the first heating element can be secured, thereby efficiently cooling the first heating element. This not only makes it possible to reduce the size of the first heating element, but also reduces the maximum heat generation temperature of the first heating element, thereby reducing the required cooling capacity of the heat sink and making it smaller, thereby enabling further miniaturization of electronic devices.

[0028] In the electronic device configured as described above, the length of the first heating element in the thickness direction is configured to be shorter than the length of the second heating element in the thickness direction.

[0029] In this way, by making the second heating element disposed in the first extension portion the heating element that is longer in the thickness direction, it is possible to reduce the height of the power conversion device.

[0030] In the electronic device configured as described above, the thermal conductivity of the heat transfer member is configured to be higher than the thermal conductivity of the heat sink.

[0031] In this way, the second heat transfer member on which the first heat generating element is disposed has high thermal conductivity, and therefore can efficiently and quickly transfer heat from the first heat generating element in the XY plane. Furthermore, by configuring the heat sink to expand in the XY plane, the height of the heat sink can be shortened, allowing the power conversion device to have a low profile. Furthermore, the first heat transfer member on which the second heat generating element is disposed can be cooled by the heat sink by transferring heat from the second heat generating element in the X direction. This eliminates the need for a separate cooler to cool the second heat generating element, thereby enabling space savings.

[0032] Furthermore, the electronic device configured as described above comprises a plurality of the second heating elements and a plurality of the first extension portions extending outward from the outer edge of the heat sink, and the second heating elements are respectively disposed on the first extension portions.

[0033] With this configuration, when a plurality of second heating elements such as capacitors or resistor elements are provided, the heat generated in each second heating element can be thermally isolated and transferred to the heat sink via each thermally isolated first extension portion, thereby preventing heat transfer between the second heating elements and enabling efficient heat dissipation.

[0034] Embodiment 2. Hereinafter, a second embodiment of the present disclosure will be described with reference to the drawings, focusing on differences from the first embodiment described above. The same components as those in the first embodiment will be assigned the same reference numerals and will not be described again. FIG. 2 is a side view showing a schematic configuration of a power conversion device 50 according to the second embodiment. In this embodiment, a substrate 203 serving as a wiring board is disposed on the Z+ side above the first heating element 1 and the second heating element 2. The first heating element 1 and the second heating element 2 are electrically connected to the substrate 203 by lead terminals 1L and 2L, which serve as terminals that lead out the respective electrodes of the first heating element 1 and the second heating element 2 to the outside.

[0035] In this way, the first heating element 1 and the second heating element 2 are configured to be disposed on the negative Z-side downward relative to the substrate 203. The second heating element 2 is configured to be located between the substrate 203 and the first extension portion 30AO in the height direction Z.

[0036] Here, the length of the distance H in the height direction Z between the bottom surface of the second heating element 2 on the negative Z-side downward direction and the substrate 203 may be determined in advance. In this case, the length of the heat sink 20 in the height direction Z is adjusted in advance so that the heat sink 20 and the first heating element 1 are housed within the range of this determined distance H. Furthermore, the area of ​​the heat sink 20 in the XY plane orthogonal to the height direction Z is also adjusted so that the heat sink 20 has thermal resistance that allows it to dissipate heat from the first heating element 1 and the second heating element 2.

[0037] According to the cooling structure of the power conversion device 50 configured in this manner, the second heating element 2 is arranged on the heat sink 20 side on the downward Z-side of the substrate 203 where the ambient temperature is low, and the second heating element 2 is not arranged on the upward Z+ side of the substrate 203 where the ambient temperature is high. Therefore, it is possible to efficiently cool the second heating element 2, and by reducing the height in the height direction Z, it is possible to make the power conversion device 50 low-profile.

[0038] The substrate 203 may be, for example, a substrate having a circuit for driving the first heating element 1, which is a semiconductor module, a drive timing control circuit, etc., or a copper substrate for electrically connecting the terminals of the semiconductor module to the second heating element 2.

[0039] Here, if the second heating element is disposed on the upward Z+ side of the substrate, heat is dissipated via the first heating element connected to the substrate, resulting in heat reception by the first heating element. In the power conversion device of this embodiment, heat generated by the resistance element serving as the second heating element is dissipated via the first extension portion extending outward from the heat sink 20, and is not transferred to the substrate. Therefore, heat reception between the heating elements is eliminated, and compared to the case where heat reception occurs between the heating elements, the maximum heat generation temperature can be reduced and the resistance element serving as the second heating element can be made smaller.

[0040] Third Embodiment Hereinafter, a third embodiment of the present disclosure will be described with reference to the drawings, focusing on differences from the first embodiment described above. Portions similar to those in the first embodiment described above will be assigned the same reference numerals and description thereof will be omitted. Fig. 3 is a side view showing a schematic configuration of a power conversion device 50 according to the third embodiment. Fig. 4 is a top view showing a schematic configuration of a power conversion device 50 according to the third embodiment.

[0041] In this embodiment, a third heat transfer member 330B is provided as a heat transfer member independent of the second heat transfer member 30B and is disposed on the upper surface 20U of the heat sink 20. This third heat transfer member 330B forms a second extension portion 330BO that extends from the outer edge of the heat sink 20 toward the second heating element 2 in a plane perpendicular to the height direction Z, and this second extension portion 330BO is in contact with the upper surface of the second heating element 2 on the + upward direction Z side. In this way, the second heating element 2 is sandwiched between the first extension portion 30AO and the second extension portion 330BO in the height direction Z, and heat is transferred to the upper surface 20U and the lower surface 20D of the heat sink 20.

[0042] According to the cooling structure of the power conversion device 50 configured in this manner, the heat generated by the capacitor element or the like, which is the second heating element 2, can be cooled by being efficiently transferred to the heat sink via the heat transfer member through the multiple surfaces of the second heating element 2. Therefore, it is possible to reduce the size of the second heating element 2, and also to reduce the maximum heat generation temperature of the first heating element 1 and thereby reduce the size, without transferring the heat generated by the second heating element 2 to the first heating element 1.

[0043] In the above example, the second extension portion 330BO is attached to the upper surface of the second heating element 2 on the Z+ side in the upward direction, but this is not limiting. For example, the second extension portion 330BO may be bent so that it is attached to the side surface of the second heating element 2.

[0044] Fourth Embodiment. Hereinafter, a fourth embodiment of the present disclosure will be described with reference to the drawings, focusing on differences from the first embodiment. Portions similar to those in the first embodiment will be assigned the same reference numerals and will not be described again. FIG. 5 is a side view showing a schematic configuration of a power conversion device 50 according to the fourth embodiment. In this embodiment, the first heating element 1 and the second heating element 2 are electrically connected by a bus bar 404 serving as a conductor. The bus bar 404 is configured to be disposed on the first extension portion 30AO via a fourth heat transfer member 430C, which is an insulating member.

[0045] According to the cooling structure of the power conversion device 50 configured in this manner, heat generated by passing electricity between the first heating element 1 and the second heating element 2 via the bus bar 404 is transferred to the first extension portion 30AO via the fourth heat transfer member 430C, thereby preventing heat from being received between the first heating element 1 and the second heating element 2. In this way, even in a configuration in which the first heating element 1 and the second heating element 2 are connected by the bus bar 404, it is possible to reduce the maximum heat generation temperature and make the power conversion device 50 smaller.

[0046] In the above description, the bus bar 404 is disposed on the first extension portion 30AO via the fourth heat transfer member 430C, which is an insulating member, but the present invention is not limited to this. For example, in order to reduce the size of the second heating element 2, the bus bar 404 may be disposed on the second heat transfer member 30B on the heat sink 20 on which the first heating element 1 is disposed via the fourth heat transfer member 430C, which is an insulating member.

[0047] Fifth Embodiment A fifth embodiment of the present disclosure will now be described with reference to the drawings, focusing on differences from the first embodiment. Portions similar to those in the first embodiment will be assigned the same reference numerals and will not be described again. Figure 6 is a side view showing the schematic configuration of an electric drive unit 100 equipped with a power conversion device 50 according to the fifth embodiment.

[0048] As shown in Figure 6, the electric drive device 100 includes an inverter unit 61 in which a power conversion device 50 is housed within an inverter cover 61C, and a motor unit 60 as a drive unit in which a motor 601 is housed within a motor cover 60C as an enclosure. In this embodiment, the power conversion device 50 is an inverter that is electrically connected to the motor 601 and supplies power to the motor 601. The inverter unit 61 and the motor unit 60 are separated by a first wall surface 60CU on the upward Z+ side of the motor cover 60C. A first extension portion 30AO of the power conversion device 50 is attached to the upper surface of this first wall surface 60CU.

[0049] The motor section 60 includes a motor 601 and an oil cooling system 670 as an oil cooler that cools the motor 601. The oil cooling system 670 has an oil cooler water passage 671 as a flow path through which cooling water flows as a refrigerant. The electric drive device 100 also includes a reducer section (not shown) that is connected to the motor section 60 and is made up of a reducer cooling system and a reducer cover.

[0050] The oil cooling system 670 circulates hydraulic oil (not shown) through the motor 601 or each heat-generating part of the electric drive device 100, and passes cooling water through an oil cooler water passage 671, which is part of the oil cooling system 670. The circulating high-temperature hydraulic oil is then heat-exchanged with the cooling water passing through the oil cooler water passage 671, and the cooled hydraulic oil is supplied to the motor 601 or each heat-generating part of the electric drive device 100.

[0051] An oil cooler water channel 671, through which cooling water flows, is disposed in contact with the underside of the first wall surface 60CU that separates the inverter unit 61 and the motor unit 60. This allows the cooling water that cools the high-temperature hydraulic oil circulating within the oil cooling system 670 to be cooled by the heat sink 20 via the first extension portion 30AO. In this way, the required cooling capacity of the oil cooling system 670 that cools the motor 601 is reduced, thereby simplifying the configuration of the oil cooling system 670 and enabling space-saving of the cooler that constitutes the oil cooling system 670.

[0052] In addition, by separating the motor section 60 and the inverter section 61 by the first wall surface 60CU of the motor cover 60C and making each space independent, the spaces of the inverter section 61 and the motor section 60 are made independent and heat exchange can be suppressed.

[0053] The first extension portion 30AO may be configured to be in surface contact with the oil cooler water passage 671, or may be configured to be embedded within the oil cooler water passage 671. The first extension portion 30AO may be configured to be in contact with the oil cooler water passage 671, through which cooling water flows, so that heat exchange occurs between the first extension portion 30AO and the cooling water, which serves as a refrigerant. The first extension portion 30AO may also be embedded within the first wall surface 60CU.

[0054] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0055] 1 First heating element (heating element), 2 Second heating element (heating element), 20 Heat sink, 30A First heat transfer member (heat transfer member), 30B Second heat transfer member (heat transfer member), 330B Third heat transfer member (heat transfer member), 430C Fourth heat transfer member (heat transfer member), 1L Lead terminal (terminal), 2L Lead terminal (terminal), 203 Substrate (wiring board), 601 Motor, 670 Oil cooling system (oil cooler), 50 Power conversion device (electronic device), 100 Electric drive device.

Claims

1. An electronic device including a heating element, a heat transfer member that transfers heat from the heating element, and a heat sink that dissipates heat from the heating element, wherein a first heating element as the heating element is disposed on a first main surface on a first direction side in the thickness direction of the heat sink, and a first heat transfer member as the heat transfer member is disposed on a second main surface of the heat sink, which is the back surface of the first main surface, and the first heat transfer member has a first extension portion that extends outward from an outer edge of the heat sink, and a second heating element as the heating element is disposed on a surface on the first direction side of the first extension portion, and the first heating element and the second heating element are thermally insulated from each other.

2. The electronic device according to claim 1, wherein a maximum heat generation amount of the first heating element is configured to be larger than a maximum heat generation amount of the second heating element.

3. The electronic device according to claim 1 or claim 2, wherein a length of the first heating element in the thickness direction is configured to be shorter than a length of the second heating element in the thickness direction.

4. The electronic device according to any one of claims 1 to 3, wherein a thermal conductivity of the heat transfer member is configured to be higher than a thermal conductivity of the heat sink.

5. The electronic device according to any one of claims 1 to 4, further including a second heat transfer member as the heat transfer member, which is configured independently of the first heat transfer member, and is disposed between a bottom surface on a second direction side of the first heating element and the first main surface of the heat sink.

6. The electronic device according to claim 5, further including a third heat transfer member as the heat transfer member, which is independent of the second heat transfer member, and is disposed on the first main surface of the heat sink, and the third heat transfer member has a second extension portion that extends from an outer edge of the heat sink toward the second heating element, and the second extension portion is configured to be in contact with the second heating element.

7. The electronic device according to claim 6, wherein the second extension portion is configured to be in contact with a surface on the first direction side of the second heating element.

8. The electronic device according to any one of claims 1 to 7, wherein a wiring board is disposed on the first direction side of the first heating element and the second heating element, and the first heating element and the second heating element are each electrically connected to the wiring board by terminals that lead out respective electrodes of the first heating element and the second heating element to the outside.

9. The area of the heat sink in a plane orthogonal to the thickness direction and the length in the thickness direction are adjusted and configured such that the heat sink and the first heating element are accommodated within a distance range in the thickness direction between the bottom surface on the second direction side of the second heating element and the wiring board. The electronic device according to claim 8.

10. The first heating element and the second heating element are connected by a conductor, and the conductor is fixed on the first heat transfer member via a fourth heat transfer member as the heat transfer member. The electronic device according to any one of claims 1 to 9.

11. The first heating element and the second heating element are connected by a conductor, and the conductor is fixed on the second heat transfer member via a fourth heat transfer member as the heat transfer member. The electronic device according to claim 5.

12. The electronic device includes a plurality of the second heating elements and a plurality of the first extending portions extending outward from the outer edge of the heat sink, and the second heating elements are respectively disposed on the first extending portions. The electronic device according to any one of claims 1 to 11.

13. An electric drive device including the electronic device according to any one of claims 1 to 12, a motor driven by the electronic device, and an oil cooler that cools hydraulic oil flowing in the motor with a refrigerant, the oil cooler being housed in an outer casing. The first wall surface on the first direction side of the outer casing is configured to have the first heat transfer member of the electronic device, and the first heat transfer member is configured such that a flow path through which the refrigerant of the oil cooler flows is in contact with the first heat transfer member so that heat exchange occurs between the first heat transfer member and the refrigerant. Electric drive device.

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