Drive device

Abstract

The present invention applies to a drive device comprising: a rotary electric machine; an inverter device that transmits and receives electric power to and from the rotary electric machine; and a transmission that changes and outputs the rotation of the rotary electric machine. The rotary electric machine is housed in a motor chamber in a housing, and an inverter chamber for housing the inverter device is provided above the motor chamber in the housing. A transmission housing in which the transmission is housed is connected to a side part of the housing at one end side of the rotary shaft of the rotary electric machine. The housing has a recessed part that is a side part on one end side, is positioned between the rotary electric machine and the inverter device, and is recessed in a direction away from the transmission housing. The inverter device has disposed therein a heat-resistant component among the components of the inverter device at a location adjacent to the recessed part.

Description

Drive unit

[0001] The present invention relates to a drive device.

[0002] A drive device is known that is miniaturized by integrating a motor, an inverter device, and a gearbox. In such a configuration, it is necessary to take appropriate measures to prevent heat from being generated by the inverter device. JP2021-182827A discloses a drive device that is configured to maintain a low temperature, particularly near a current sensor that has a low heat resistance temperature, by flowing a coolant through the motor and the inverter device.

[0003] As mentioned above, the motor and inverter device can be cooled by a refrigerant. However, because the gearbox has a high heat resistance temperature, the temperature of the gearbox rises higher than that of the motor and inverter device, which are cooled by a refrigerant. Therefore, in an integrated drive unit, if heat from the gearbox is transferred to components of the inverter device located close to the gearbox, there is a possibility that the temperature of those components will rise more than necessary.

[0004] The present invention has been made in view of the above problems, and has an object to provide a drive device that can take more effective measures against heat in an inverter device.

[0005] According to one aspect of the present invention, a drive device includes a rotating electric machine, an inverter device that exchanges electric power with the rotating electric machine, and a transmission that changes the speed of rotation of the rotating electric machine and outputs the result. The rotating electric machine is accommodated in a motor chamber within a housing, and an inverter chamber that accommodates the inverter device is provided above the motor chamber in the housing. A transmission housing that accommodates the transmission is connected to a side of the housing at one end of a rotating shaft of the rotating electric machine. The housing has a recessed portion at the side of the one end, located between the rotating electric machine and the inverter device, and recessed in a direction away from the transmission housing. Heat-resistant components of the inverter device are arranged adjacent to the recessed portion.

[0006] Fig. 1 is a perspective view of a drive device according to this embodiment, Fig. 2 is a cross-sectional view of the drive device, Fig. 3 is an explanatory diagram of an inverter device, and Fig. 4 is a side view of the drive device.

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] Fig. 1 is a perspective view showing the configuration of a drive device 1 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the drive device 1. Fig. 3 is an explanatory diagram of an inverter device 20 as viewed from the motor 10 side. Fig. 4 is a side view of the drive device 1 showing the configuration of a gearbox 30.

[0009] The drive unit 1 is integrally configured and includes a rotating electric machine (motor) 10, a power conversion device (inverter device) 20, and a speed reducer (gearbox) 30. The drive unit 1 is mounted on an electric vehicle and configured as a driving force source that drives the electric vehicle by driving the motor 10.

[0010] The motor 10 is driven by power supplied from the inverter device 20 and transmits rotation to drive wheels (not shown) to drive the electric vehicle. The motor 10 also functions as a generator that generates regenerative power when the electric vehicle decelerates.

[0011] The inverter device 20 receives power from a battery (not shown), converts it into power suitable for driving the motor 10, and supplies it to the motor 10. It also receives regenerative power from the motor 10, converts it into power suitable for charging the battery, and charges the battery.

[0012] The gearbox 30 reduces the speed of the rotation of the motor 10 and outputs the reduced speed. The output of the gearbox 30 is transmitted to the drive wheels.

[0013] As shown in Fig. 2, the inverter device 20 and the motor 10 are housed in a housing 50. The housing 50 includes a cylindrical hollow motor chamber 51 and a recessed inverter chamber 52 formed above the motor chamber 51. The motor 10 is housed in the motor chamber 51, and the inverter device 20 is housed in the inverter chamber 52. An inverter cover 53 is fixed to the top of the inverter chamber 52.

[0014] The inverter device 20 includes components such as a power module 21, a smoothing capacitor 22, a noise filter 23, a bus bar 24, and a current sensor 25. As shown in Fig. 3, these components are arranged in the direction of the rotation axis of the motor 10 from the gearbox 30 side in the order of the noise filter 23, smoothing capacitor 22, power module 21, and current sensor 25.

[0015] 2, the motor 10 is configured to include a stator 11, a rotor 12, and a rotating shaft 13. The rotating shaft 13 is rotatably supported by a housing 50, and one end (on the right side in FIG. 2) of the rotating shaft 13 penetrates the side wall of the housing 50 and extends into the gear box 30.

[0016] In the housing 50, a cooling water flow path 55 is formed around the outer periphery of the motor chamber 51, through which cooling water flows to cool the motor 10. The cooling water flow path 55 is also arranged in a portion that separates the motor chamber 51 from the inverter chamber 52, and cools the inverter device 20 together with the motor 10.

[0017] The gearbox 30 is connected to one end (the right side in FIG. 2 ) of the housing 50. The gearbox 30 includes a reducer housing 60 formed across the front-to-rear direction of the vehicle, and multiple gears are housed inside the reducer housing 60. The rotating shaft 13 of the motor 10 extends toward the gearbox 30 and is coaxially connected to the first shaft 31.

[0018] 4, the gearbox 30 includes a first shaft 31 having a first gear 31a, a second shaft 32 having a second gear 32a, and a third shaft 33 having a third gear 33a. The first shaft 31 is connected to the rotary shaft 13 of the motor 10, and the rotation of the first shaft 31 is transmitted to the second shaft 32 by a second gear 32a meshing with the first gear 31a. The rotation of the second shaft 32 is transmitted to the third shaft 33 by a third gear 33a meshing with the second gear 32a. The third shaft 33 is connected to the drive wheels and drives the drive wheels.

[0019] Next, a description will be given of heat countermeasures for the drive device 1 configured as above.

[0020] Since the drive device 1 generates heat when driven, the motor 10 and the inverter device 20 are cooled by cooling water flowing through a cooling water passage 55 in the housing 50 .

[0021] On the other hand, the gearbox 30 is designed to be lubricated and cooled by the lubricating oil in the reducer housing 60, but since it does not have any electrically driven components, its heat resistance temperature is higher than that of the motor 10 and the inverter device 20, and when the drive device 1 is in operation, the temperature of the gearbox 30 (e.g., 120°C) becomes higher than the temperature of the motor 10 and the inverter device 20 (e.g., 90°C).

[0022] On the other hand, the inverter device 20 includes components with a relatively low heat resistance temperature, such as the current sensor 25 and the power module 21 that requires cooling with cooling water. Therefore, if heat from the gearbox 30 is transferred to the inverter device 20 via the housing 50 or the like, there is a possibility that the components with a relatively low heat resistance temperature will be affected. For this reason, it is necessary to take appropriate heat countermeasures for the inverter device 20.

[0023] In this embodiment, the inverter device 20 is configured to be able to take appropriate measures against heat by providing the following configuration.

[0024] As shown in Fig. 2, a side portion (left side in a front-to-rear view of the vehicle) of the housing 50 on one end side of the rotary shaft 13 is provided with a recessed portion 80 that is located between the motor chamber 51 and the inverter chamber 52 in the vehicle height direction and is recessed (configured to be recessed) in a direction away from the gearbox 30. The recessed portion 80 is a side wall of the housing 50 to which the reducer housing 60 is fixed, and is provided in an upper part of a partition wall portion located between the motor chamber 51 and the gearbox 30. As shown in Fig. 4, the recessed portion 80 is formed in the shape of a passage extending in the front-to-rear direction of the vehicle, and is interposed between the inverter device 20 and the gearbox 30.

[0025] In this way, the recessed portion 80 is interposed between the inverter device 20 and the gear box 30 at a position higher than the gear box 30, thereby increasing the surface distance between the inverter device 20 and the gear box 30 in the housing 50, and the low heat transfer coefficient of the air present in the space of the recessed portion 80 prevents heat from the gear box 30 from being transferred to the inverter device 20.

[0026] Within the inverter device 20, a noise filter 23 is disposed closest to the gear box 30, and a current sensor 25 is disposed farthest from the gear box 30. The noise filter 23 is made up of a coil, a core, etc., and is a component that reduces high-frequency noise in the inverter device 20. The noise filter 23 is a heat-resistant component that has a higher heat-resistance temperature than the other components of the inverter device 20.

[0027] In this way, in the inverter device 20, by using the noise filter 23, which is a heat-resistant component, as the component closest to the gear box 30, it is possible to minimize the influence of heat from the gear box 30.

[0028] Next, the configuration of the gear box 30 will be described.

[0029] As shown in Figure 4, in the gearbox 30, the first shaft 31, the second shaft 32, and the third shaft 33 are arranged in this order from the front to the rear of the vehicle. The first gear 31a has the smallest diameter, and the third gear 33a has the largest diameter. Furthermore, the second shaft 32 is arranged lower than the first shaft 31 in the vehicle height direction. Furthermore, the third gear 33a, which has the largest diameter, is arranged at a position extending further rearward than the motor 10 and the inverter device 20.

[0030] In the gearbox 30, the recessed portion 80 is disposed above the first shaft 31 having the first gear 31a with the smallest diameter and the second shaft 32 disposed at a lower position, thereby providing a large space for the recessed portion 80. This allows the recessed portion 80 to be formed large in the height direction and long in the front-to-rear direction. By configuring the recessed portion 80 in this manner, the distance between the inverter device 20 and the gearbox 30 is increased, thereby suppressing the transfer of heat from the gearbox 30 to the inverter device 20.

[0031] In particular, the gearbox 30 is composed of a three-shaft reduction mechanism as shown in Figure 4, and the first shaft 31 is connected to the rotating shaft 13 of the motor 10, so the first shaft 31 rotates the fastest. As a result, the area around the first shaft 31 becomes the hottest part of the gearbox 30.

[0032] The recessed portion 80 increases the distance between the highest temperature point in the gear box 30 and the inverter device 20 , thereby suppressing the transfer of heat from the gear box 30 to the inverter device 20 .

[0033] Note that multiple ribs 80a are formed on the inner surface of the recessed portion 80, as shown in Figure 4. If the recessed portion 80 is made larger in the height direction, the flat portion shown by hatching in Figure 4 will become larger, which may reduce the rigidity of this portion of the housing 50, but by forming the ribs 80a in the recessed portion 80, it is possible to prevent a decrease in rigidity. Furthermore, the ribs 80a increase the surface area of ​​the inner surface of the recessed portion 80, thereby improving the heat dissipation efficiency of the recessed portion 80.

[0034] As shown in FIG. 4 , a ventilation hole 35 that connects the front surface of the housing 50 and the inner surface of the recessed portion 80 is provided on the front side of the recessed portion 80 , that is, on the front surface side of the housing 50 .

[0035] With this configuration, the wind generated by running and the air blown by the radiator fan 71 are sent into the recessed portion 80 through the ventilation holes 35, and the air in the recessed portion 80 moves, further suppressing the transfer of heat from the gearbox 30 to the inverter device 20. Furthermore, the ribs 80a formed on the inner surface of the recessed portion 80 dissipate the heat transferred from the gearbox 30. Note that the drive unit 1 may be configured without the radiator 70 and the radiator fan 71. In this case as well, the wind generated by running is sent into the recessed portion 80 through the ventilation holes 35.

[0036] As described above, in this embodiment, the drive unit 1 includes a rotating electric machine (motor 10), an inverter device 20 that exchanges electric power with the motor 10, and a transmission (gearbox 30) that changes the speed of rotation of the motor 10 and outputs the rotation. In a housing 50, the motor 10 is accommodated in a motor chamber 51 within the housing 50, and an inverter chamber 52 that accommodates the inverter device 20 is provided above the motor chamber 51. A reducer housing 60 that accommodates a speed reduction mechanism is connected to a side of the housing 50 at one end of the rotating shaft 13 of the motor 10. The housing 50 has a recessed portion 80 on the side of the one end, located between the motor 10 and the inverter device 20, and recessed in a direction away from the reducer housing 60. Heat-resistant components of the inverter device 20 are disposed adjacent to the recessed portion 80.

[0037] In this configuration, the recessed portion 80 provided between the inverter device 20 and the gear box 30 increases the creepage distance between them in the housing 50, and the air present in the recessed portion 80 suppresses the transfer of heat from the gear box 30 to the inverter device 20. Furthermore, since a heat-resistant component is disposed adjacent to the gear box 30, the influence of heat from the gear box 30 on the inverter device 20 can be suppressed.

[0038] In this embodiment, the heat-resistant part is the noise filter 23, which is a component for a noise filter. In this configuration, the component with the highest heat resistance temperature among the components of the inverter device 20 is disposed adjacent to the gear box 30, so that the influence of heat from the gear box 30 on the inverter device 20 can be further suppressed.

[0039] In addition, in this embodiment, ventilation holes 35 are provided that communicate from the outside of the housing 50 to the inner surface of the recessed portion 80. In this configuration, the airflow can pass through the concave-shaped recessed portion 80, thereby reducing the temperature of the recessed portion 80 and further suppressing the transfer of heat from the gearbox 30 to the inverter device 20.

[0040] In this embodiment, the recessed portion 80 is formed in the shape of a passage extending in the longitudinal direction of the vehicle. With this configuration, the transmission of heat from the gear box 30, which is disposed across the longitudinal direction of the vehicle, to the inverter device 20 is further suppressed.

[0041] In this embodiment, the gearbox 30 is a reducer and includes a first shaft 31 connected to the rotary shaft 13 of the motor 10, a second shaft 32 meshing with the first shaft 31, and a third shaft 33 meshing with the second shaft 32. The second shaft 32 is disposed at a lower position in the vehicle height direction than the first shaft 31 and the third shaft 33, and the recessed portion 80 is formed above the first shaft 31 and the second shaft 32 across the front-to-rear direction of the vehicle.

[0042] In this configuration, the area around the first axis 31, which is the area with the highest temperature in the gearbox 30, is at a greater distance from the inverter device 20 due to the presence of the recess 80, thereby further suppressing the transfer of heat from the gearbox 30 to the inverter device 20.

[0043] In this embodiment, the recessed portion 80 has a plurality of ribs 80a extending from its inner surface. This configuration increases the surface area of ​​the inner surface of the recessed portion 80, thereby improving heat dissipation and increasing the rigidity of the recessed portion 80.

[0044] In this embodiment, the radiator fan 71 is disposed on the front side of the drive unit 1, and the air blown from the radiator fan 71 passes through the ventilation holes 35 into the recessed portion 80. In this configuration, the heat from the recessed portion 80 is more effectively dissipated, and the heat from the gearbox 30 is less likely to be transmitted by the inverter device 20.

[0045] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0046] In the present embodiment, the gearbox 30 has been described as a speed reducer, but this is not limiting, and the gearbox 30 may be configured as a stepped or continuously variable transmission.

[0047] In addition, in this embodiment, the rib 80a is formed on the inner periphery of the recessed portion 80, but this is not limited thereto, and a plurality of fin-shaped structures whose main purpose is to dissipate heat may be provided on the inner periphery of the recessed portion 80.

Claims

1. A drive device comprising a rotating electrical machine, an inverter device that exchanges power with the rotating electrical machine, and a transmission that changes the speed of rotation of the rotating electrical machine and outputs it, wherein the rotating electrical machine is housed in a motor chamber within a housing, in the housing, an inverter chamber for housing the inverter device is provided above the motor chamber, a transmission housing for housing the transmission is connected to a side portion of the housing on one end side of the rotating shaft of the rotating electrical machine, the housing has a recessed portion that is recessed in a direction away from the transmission housing and is located between the rotating electrical machine and the inverter device on the side portion of the one end side, and the inverter device has heat-resistant components among the components of the inverter device arranged at a location adjacent to the recessed portion. Drive device.

2. The drive device according to claim 1, wherein the heat-resistant component is a component for a noise filter. Drive device.

3. The drive device according to claim 1, wherein the drive device is mounted on a vehicle and configured as a driving power source of the vehicle, and has a ventilation hole that communicates from the front side of the housing to the inner surface of the recessed portion. Drive device.

4. The drive device according to claim 3, wherein the recessed portion is formed in a passage shape extending in the longitudinal direction of the vehicle. Drive device.

5. The drive device according to claim 3, wherein the transmission is a reduction gear, and includes a first shaft connected to the rotating shaft of the rotating electrical machine, a second shaft meshing with the first shaft, and a third shaft meshing with the second shaft, the second shaft is disposed at a position lower in the vehicle height direction than the first shaft and the third shaft, and the recessed portion is formed over the vehicle longitudinal direction above the first shaft and the second shaft. Drive device.

6. The drive device according to claim 5, wherein the recessed portion has a plurality of ribs standing on its inner surface. Drive device.

7. The drive device according to claim 3, wherein a radiator fan is disposed in front of the drive device, and the air blown from the radiator fan passes from the ventilation hole to the recessed portion. Drive device.

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