Drive device

Abstract

The rotating electric machine has a motor housing having a recess in an upper portion thereof. The inverter device has a cover-shaped inverter case, an electrical component is disposed on the inner surface of the inverter case facing the rotating electrical machine, and the inverter case is fixed to the rotating electrical machine case, so that a housing chamber for housing the electrical component is formed by the inverter case and the recess. In the housing chamber, the electrical components include a first electrical component and a second electrical component having a higher temperature than the first electrical component, and the first electrical component and the second electrical component are disposed so as to be separated from each other in the axial direction of the rotating electrical machine.

Description

Technical Field

[0001] The invention relates to a driving device. Background Art

[0002] The power conversion device for supplying electric power to a rotating electric machine is configured to accommodate and install electric components such as a power module, a capacitor module, and a bus bar in a housing. JP6406443B discloses a structure in which a power module and a capacitor module are arranged on the upper surface of a support member having a cooling flow path, and the support member is accommodated in a motor housing and sealed with an upper surface plate. Summary of the invention

[0003] In the prior art, a support component is required to cool the power module and an upper surface plate is required to cover the motor housing, so the number of components increases, resulting in problems of increased size and weight. In order to reduce the size and weight, a structure in which the support component is omitted is also considered. In this case, there is the following problem, namely, electrical components that generate heat, such as bus bars, are likely to affect other electrical components.

[0004] The present invention has been made in view of such a problem, and an object of the present invention is to provide a technology for suppressing the influence of heat on electrical components.

[0005] One embodiment of the present invention is applied to a drive device, which has: a rotating electric machine; and an inverter device, which is placed on the upper part of the rotating electric machine and supplies and receives electric power to and from the rotating electric machine. The drive device has a motor housing for accommodating the rotating electric machine, and the motor housing has a recessed portion on its upper part. The inverter device has a cover-shaped inverter housing, and electrical components are arranged on the inner surface of the inverter housing facing the rotating electric machine. The inverter housing is fixed to the rotating electric machine housing, so that a receiving chamber for accommodating the electrical components is formed by the recessed portions of the inverter housing and the motor housing. In the receiving chamber, the electrical components include a first electrical component and a second electrical component whose temperature is higher than that of the first electrical component, and the first electrical component and the second electrical component are arranged separately in the axial direction of the rotating electric machine.

[0006] Effects of the Invention

[0007] According to the present invention, electrical components are arranged on the inner surface of the inverter housing, and the electrical components are accommodated in the accommodation chamber between the inverter housing and the motor housing, and the high-temperature second electrical components are arranged separately from the first electrical components, thereby suppressing the heat conduction of the second electrical components to the first electrical components. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a cross-sectional view of a driving device according to an embodiment of the present invention.

[0009] Figure 2is a cross-sectional view of an inverter device.

[0010] Figure 3 It is an oblique view of the motor housing.

[0011] Figure 4 It is an oblique view of the drive device. DETAILED DESCRIPTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like.

[0013] Figure 1 It is a structural diagram of a driving device 1 according to an embodiment of the present invention.

[0014] The drive device 1 includes a power conversion device (inverter device) 10, a motor 20, and a speed reducer 30. The drive device 1 is mounted on an electric vehicle, receives power from a battery (not shown) and drives the motor 20, thereby driving the electric vehicle.

[0015] The motor 20 transmits the rotation to the drive wheels via the speed reducer 30 to drive the electric vehicle. The motor 20 also functions as a generator that generates electricity and obtains regenerative power when the electric vehicle is decelerated. The speed reducer 30 decelerates the rotation of the rotating shaft 22 of the motor 20 and transmits the decelerated rotation to the drive wheels. The motor 20 and the speed reducer 30 are arranged in the motor housing 21.

[0016] The motor 20 includes an inner housing 23, a stator 24, and a rotor 25. The inner housing 23 that accommodates the stator 24 and the rotor 25 is configured to be embedded in the motor housing 21. A gap is formed between the motor housing 21 and the inner housing 23, and the gap is configured as a cooling water flow path 41. The cooling water flow path 41 is formed so that cooling water circulates around the outer periphery of the stator 24 of the motor 20. The rotating shaft 22 is provided at the rotation center of the rotor 25. The rotating shaft 22 is connected to the speed reducer 30.

[0017] The inverter device 10 is disposed on the upper portion of the motor case 21. The inverter device 10 includes an inverter case 11 and electrical components such as a power module 12, a capacitor module 13, and a three-phase inverter-side bus bar 14 housed in the inverter case 11.

[0018] The inverter housing 11 is formed into a box shape with its outer edge extending toward the motor housing 21 and open toward the bottom. The inverter housing 11 covers the motor housing 21 in a cover shape and is fixed to the motor housing 21 by bolts or the like. When the inverter housing 11 is fixed to the motor housing 21, the space formed by the inner surface of the inverter housing 11 and the recessed portion 21a on the upper side of the motor housing 21 constitutes a storage chamber 101 for storing electrical components.

[0019] In the accommodation chamber 101, the power module 12 and the capacitor module 13 are fixed to the inner surface of the inverter housing 11 and are arranged to face the motor housing 21. The inverter-side bus bar 14 is connected to the power module 12 on the inverter housing 11 side, and is arranged to face the motor housing 21 at a position separated from the power module 12. The front end portion of the inverter-side bus bar 14 is connected to the motor-side bus bar 28.

[0020] A three-phase motor-side bus bar 28 is extended from the upper part of the axial end of the motor 20. The motor-side bus bar 28 is composed of the following components: an extended portion 28a extending from the coil end 27 of the motor 20 toward the outside in the axial direction ( Figure 1 and an upper extension portion 28b extending upward from the end of the extension portion 28a.

[0021] The motor-side bus bar 28 and the inverter-side bus bar 14 are fixed by a connection portion 29. The connection portion 29 is composed of a bolt and a nut, and is fastened together with a fixing hole formed in the inverter-side bus bar 14 and a fixing hole formed in the upper extension portion 28b of the motor-side bus bar 28 to make them electrically conductive.

[0022] Next, the arrangement of electrical components of the inverter device 10 configured in this manner will be described.

[0023] The storage chamber 101 of the inverter device 10 includes a power module 12, a capacitor module 13, and an inverter-side bus bar 14. The lower end of the inverter-side bus bar 14 is connected to the motor-side bus bar 28 by a connection portion 29.

[0024] Here, the conduction of heat of the above-mentioned electrical components included in the housing chamber 101 of the inverter device 10 will be described.

[0025] Generally, functional electrical components such as the power module 12 and the capacitor module 13 are electrical components (hereinafter referred to as "first electrical components") that determine the upper limit of the operating temperature and have a relatively low heat resistance temperature (e.g., 150°C). On the other hand, wire components such as the inverter-side bus bar 14 and the motor-side bus bar 28 are electrical components (hereinafter referred to as "second electrical components") that have a relatively wide operating temperature range and a relatively high heat resistance temperature (e.g., 300°C). The motor-side bus bar 28 reaches a higher temperature due to the heat conducted from the coil end 27 of the motor 20. In addition, the connection portion 29 connecting the inverter-side bus bar 14 and the motor-side bus bar 28 reaches a relatively high temperature due to the contact resistance. In addition, the inverter-side bus bar 14 connects the connection portion 29 to the power module 12, but their creepage distance is relatively large and they are separately fixed in the inverter housing 11, so that the influence of heat on the first electrical component is relatively small.

[0026] When the first and second electrical components are arranged in the same space in the accommodation chamber 101, the operating temperature range is wide, and the heat generated by the second electrical component with a higher temperature is radiated and conducted to the first electrical component with a lower temperature than the second electrical component.

[0027] The power module 12 in the first electrical component is a component that generates heat, so it is configured to be in direct contact with the flow path of cooling water formed in the inverter housing 11 and is configured to be always cooled. The capacitor module 13 in the first electrical component generates heat in a small range, so it is configured not to be cooled by cooling water. Therefore, when the second electrical component that generates heat is arranged close to it, it receives the heat and the influence of the heat becomes greater.

[0028] In contrast, the connection portion 29 of the second electrical component that connects the inverter side bus bar 14 and the motor side bus bar 28 becomes high temperature during operation, and thus becomes a component that easily applies heat to the first electrical component. The second electrical component applies heat to the first electrical component, and as a result, the heated first electrical component sometimes approaches the heat-resistant temperature.

[0029] In order to prevent this, it is considered to form a structure in which the inverter case is box-shaped so that heat is not conducted to the electrical components in the storage chamber of the inverter device. However, this structure has a new problem of increasing the size and weight of the inverter device.

[0030] In the present embodiment, as will be described below, the inverter device 10 is configured to suppress an increase in size and weight and to prevent a problem of heat of electrical components in the inverter device 10 from occurring.

[0031] Figure 2 It is a cross-sectional view of the drive device 1 which is the core of the inverter device 10 . Figure 3 It is a perspective view of the accommodation chamber 101 of the motor case 21 in a state where the inverter device 10 is removed.

[0032] like Figure 2 As shown, the extension portion 28a of the motor side bus bar 28 extends axially from the coil end 27 of the motor 20 toward the outer side opposite to the reducer 30. The capacitor module 13 is arranged in the accommodation chamber 101 to the left of the power module 12, that is, separated from the motor side bus bar 28.

[0033] Thus, the capacitor module 13 fixed to the inverter case 11 and the connection portion 29 connecting the inverter-side bus bar 14 and the motor-side bus bar 28 are arranged to be separated in the axial direction, thereby suppressing heat transfer from the motor-side bus bar 28 and the connection portion 29 to the capacitor module 13 .

[0034] Furthermore, in the drive device 1 of the present embodiment, a flat shielding wall 102 is formed on the upper surface of the motor housing 21, that is, the bottom surface of the accommodation chamber 101, which is erected upward from the bottom surface. The shielding wall 102 divides the accommodation chamber 101 into an area where the first electrical components (power module 12, capacitor module 13) are arranged and an area where the second electrical components (motor-side bus bar 28, connection portion 29) are arranged.

[0035] More specifically, the shielding wall 102 is as follows Figure 3 As shown, it is extended in a direction orthogonal to the axial direction and is erected on the upper surface of the motor housing 21 to separate an area (the first area 111) where the inverter side bus bar 14, the motor side bus bar 28 and the connecting portion 29 are configured, and an area (the second area 112) where the power module 12 and the capacitor module 13 are configured.

[0036] Thus, the shielding wall 102 exists on the line connecting the connection portion 29 and the capacitor module 13 , thereby suppressing direct conduction of heat from the connection portion 29 to the capacitor module 13 .

[0037] The motor case 21 is configured such that the axial position where the shielding wall 102 is erected is substantially the same as the axial position where the sealing member 23 a of the inner case 23 fitted inside the motor case 21 is arranged.

[0038] The sealing member 23a of the inner housing 23 is compressed between the inner circumferential surface of the motor housing 21, thereby sealing so that the cooling water of the cooling water flow path 41 does not leak out. Therefore, a stress toward the radially outward side acts on the portion of the motor housing 21 that contacts the sealing member 23a. Therefore, by forming the shielding wall 102 at the portion where the stress of the motor housing 21 acts, the wall thickness of the motor housing 21 is increased, and the rigidity of the motor housing 21 at the portion in contact with the sealing member 23a can be improved. As a result, the cooling water of the cooling water flow path 41 can be sealed more reliably.

[0039] Furthermore, on the upper surface of the motor housing 21, that is, the bottom surface of the receiving chamber 101, and at a position opposite to the capacitor module 13, as shown in FIG. Figure 3 As shown, a plurality of flat plate-shaped ribs 103 are formed to protrude toward the capacitor module 13. A cooling water flow path 41 is formed between the motor housing 21 and the inner housing 23 of the motor 20, and the ribs 103 are arranged to be located radially outside the cooling water flow path 41 of the motor housing 21. In addition, the ribs 103 are not limited to being flat plate-shaped, and may be various shapes such as a plurality of protrusions, or concave and convex shapes formed on the upper surface of the motor housing 21.

[0040] By arranging the plurality of ribs 103 on the motor case 21, the atmosphere near the ribs 103 is cooled by cooling water. This can reduce the heat conducted from the second electric component, and in particular, the heat conducted to the capacitor module 13.

[0041] Next, the flow path of the cooling water of the drive device 1 will be described. Figure 4 It is a perspective view of the driving device 1 according to this embodiment.

[0042] The inverter housing 11 of the drive device 1 has a cooling water inlet 45 for allowing cooling water to flow in from the outside. The cooling water inlet 45 is connected to an inverter-side cooling water flow path (not shown) formed in the inverter housing 11. The cooling water flowing into the inverter-side cooling water flow path cools the electrical components (power module 12) of the inverter device 10, and then flows into the housing-side flow path 43 from the motor-side cooling water inlet 43a formed at the contact portion between the inverter housing 11 and the motor housing 21. The housing-side flow path 43 has a connecting port 44 in the motor housing 21 that is connected to the cooling water flow path 41 formed between the motor housing 21 and the inner housing 23 (see FIG. 1 ). Figure 2 The communication port 44 is disposed at a position close to the shielding wall 102 .

[0043] The motor 20 is cooled by cooling water flowing from the case side flow path 43 and flowing into the cooling water flow path 41 through the communication port 44. The cooling water flow path 41 communicates with a cooling water outlet 42 formed in the motor case. The cooling water circulating in the cooling water flow path 41 flows out from the cooling water outlet 42.

[0044] In the motor housing 21, the lowest temperature cooling water flowing in from the inverter housing 11 through the motor side cooling water inlet 43a flows into the cooling water flow path 41 through the communication port 44 located close to the shielding wall 102, thereby lowering the temperature of the shielding wall 102. Thus, the heat conducted from the second electrical component can be reduced.

[0045] As described above, the present embodiment is a drive device 1, which includes: a rotating electric machine (motor 20); and an inverter device 10, which is arranged on the upper part of the motor 20 and supplies and receives power to and from the motor 20. The motor 20 includes a motor housing 21, and the motor housing 21 includes a recessed portion 21a on the upper part thereof. The inverter device 10 includes a lid-shaped inverter housing 11, and electrical components are arranged on the inner surface of the inverter housing 11 facing the motor 20. The inverter housing 11 is fixed to the motor housing 21, so that the inverter housing 11 and the recessed portion 21a form a receiving chamber 101 for receiving the electrical components. In the receiving chamber 101, the electrical components include: a first electrical component (for example, a capacitor module 13); and a second electrical component (for example, a motor-side bus bar 28), whose temperature is higher than that of the first electrical component, and the first electrical component and the second electrical component are separated and arranged in the axial direction of the rotating electric machine.

[0046] Regarding this structure, electrical components are arranged on the inner surface of the inverter housing 11, and the electrical components are accommodated in the accommodation chamber 101 between the inverter housing 11 and the motor housing 21. The high-temperature second electrical components and the first electrical components are separated and arranged, thereby suppressing the heat conduction of the second electrical components to the first electrical components.

[0047] In the present embodiment, the recess 21 a of the motor case 21 is provided with a shielding wall 102 that partitions the space in the storage chamber 101 into a first region 111 where a first electric component is disposed and a second region 112 where a second electric component is disposed.

[0048] In this structure, since the shielding wall 102 is formed to separate the first electric component that is easily heated from the second electric component that is easily heated, direct conduction of heat from the first electric component to the second electric component is suppressed.

[0049] In addition, in this embodiment, a cylindrical inner housing 23 in which the stator 24 of the power supply machine 20 is embedded is installed in the motor housing 21. A cooling water flow path 41 is formed between the inner housing 23 and the motor housing 21. A sealing member 23a is provided at the joint portion where the inner housing 23 and the motor housing 21 are in contact, and a shielding wall 102 is erected at the outer peripheral portion of the joint portion of the motor housing 21.

[0050] In this structure, the shielding wall 102 is formed at the joint portion where the stress of the inner housing 23 acts, so that the rigidity of the motor housing 21 can be improved, and thus the cooling water in the cooling water flow path 41 can be sealed more reliably.

[0051] In the present embodiment, the first electric component is the capacitor module 13 constituting the inverter device 10 , and a rib 103 is formed in the recess 21 a at a position facing the capacitor module 13 so as to protrude toward the capacitor module 13 .

[0052] In this structure, the plurality of ribs 103 are arranged on the outer surface of the cooling water flow path 41 of the motor case 21 , so that the atmosphere near the ribs 103 can be cooled, thereby reducing the heat conducted to the capacitor module 13 .

[0053] In the present embodiment, the second electric component is a motor-side bus bar 28 for supplying and receiving three-phase electric power between the motor 20 and the inverter device 10 . The motor-side bus bar 28 is provided in the motor 20 to extend axially outward from the shielding wall 102 .

[0054] With this configuration, the motor-side bus bar 28 is disposed apart from the first electric component (capacitor module 13) in the axial direction, thereby preventing heat generated by the motor-side bus bar 28 and the connection portion 29 as the second electric component from being transferred to the first electric component.

[0055] In addition, in this embodiment, the motor housing 21 has: a motor side cooling water inlet 43a for cooling water to flow in; and a cooling water flow path 41, which allows the cooling water flowing in from the motor side cooling water inlet 43a to circulate around the periphery of the stator 24, and the connecting port 44 connecting the motor side cooling water inlet 43a and the cooling water flow path 41 is set at a position close to the shielding wall 102.

[0056] With this structure, in the motor housing 21, the cooling water with the lowest temperature flowing in from the inverter housing 11 flows into the cooling water flow path 41 through the connecting port 44 located near the shielding wall 102, thereby lowering the temperature of the shielding wall 102 and reducing the heat conducted from the second electrical component.

[0057] The embodiments and modifications of the present invention have been described above. However, the embodiments and modifications are merely examples of application of the present invention and are not intended to limit the technical scope of the present invention to the specific structures of the embodiments.

[0058] In the present embodiment, a hybrid vehicle is described in which the engine drives the generator and the hybrid vehicle runs using the driving force of the motor. However, the present invention is not limited to this and can be similarly applied to a driving device of an electric vehicle that runs using the driving force of the motor.

Claims

1. A drive device comprising: a rotating electric machine; and an inverter device, which is arranged on the upper part of the rotating electric machine and supplies and receives electric power between the rotating electric machine and the inverter device, wherein: The rotating electric machine has a motor housing having a recessed portion at an upper portion thereof. The inverter device includes a cover-shaped inverter housing, electrical components are arranged on the inner surface of the inverter housing facing the rotating electric machine, and the inverter housing is fixed to the motor housing, so that a storage chamber for storing the electrical components is formed by the inverter housing and the recessed portion. In the receiving chamber, The electrical component includes a first electrical component and a second electrical component having a higher temperature than the first electrical component. The first electric component and the second electric component are arranged to be separated from each other in the axial direction of the rotating electric machine.

2. The driving device according to claim 1, wherein: The recessed portion of the motor case has a shielding wall formed therein, the shielding wall partitioning the space in the accommodation chamber into a region where the first electric component is disposed and a region where the second electric component is disposed.

3. The driving device according to claim 2, wherein: The motor housing contains a cylindrical inner housing in which the stator of the rotating motor is embedded. A cooling water flow path is formed between the inner housing and the motor housing, and a sealing member is provided at a joint portion where the inner housing and the motor housing are in contact. The shielding wall is provided upright on the outer peripheral portion of the joining portion of the motor housing.

4. The driving device according to claim 1, wherein: The first electrical component is a capacitor module constituting the inverter device. The recessed portion has a rib formed at a position facing the capacitor module and protruding toward the capacitor module.

5. The driving device according to claim 2, wherein: The second electrical component is a three-phase bus bar that supplies and receives electric power between the rotating electrical machine and the inverter device. The three-phase bus bar is provided in the rotating electrical machine so as to extend axially outward beyond the shielding wall.

6. The driving device according to claim 2, wherein: The motor housing has a cooling water inlet into which cooling water flows, and a cooling water flow path that allows the cooling water flowing from the cooling water inlet to circulate around the outer periphery of the rotating electric machine. A communication port through which the cooling water inlet and the cooling water flow path communicate is provided at a position close to the shielding wall.

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