Driving apparatus

Abstract

This driving apparatus integrally comprises: a motor that is housed in a motor chamber of a housing; and an inverter device that is housed in an inverter chamber of the housing. The housing comprises: a motor flow path which allows a refrigerant to flow around the motor chamber; an inverter flow path which allows the refrigerant to flow around the inverter chamber so as to cool a power module included in the inverter device; an inlet flow path which is opened to the outside of the housing and allows the refrigerant to flow into the inverter flow path; a relay flow path which allows the refrigerant to flow from the inverter flow path to the motor flow path; and an outlet flow path which is opened to the outside of the housing and allows the refrigerant to be discharged from the motor flow path.

Description

Drive unit

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

[0002] JPH09-046972A discloses a drive device in which a power box (inverter device) having a switching element and a motor are cooled via a cooling water passage through which cooling water flows.

[0003] The motor and the inverter device differ in the heat they generate and in the target temperatures to which they should be cooled, so there is a problem in that simply circulating cooling water through them does not necessarily result in the motor and the inverter device being adequately cooled.

[0004] The present invention has been made in consideration of such problems, and aims to provide a drive device in which a motor and a power conversion device are integrally configured, and in which these are more appropriately cooled.

[0005] One embodiment of the present invention is a drive device that integrally includes a motor accommodated in a motor chamber of a housing and an inverter device accommodated in an inverter chamber of the housing. The housing includes a motor flow path that circulates a refrigerant around the motor chamber and an inverter flow path that circulates a refrigerant around the inverter chamber to cool a power module of the inverter device. The housing also includes an inlet flow path that opens to the outside of the housing and allows the refrigerant to flow into the inverter flow path, a relay flow path that circulates the refrigerant from the inverter flow path to the motor flow path, and an outlet flow path that opens to the outside of the housing and discharges the refrigerant from the motor flow path.

[0006] Fig. 1 is a perspective view of a drive device according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of the drive device. Fig. 3 is a cross-sectional view of the drive device. Fig. 4 is an explanatory diagram of a motor flow path. Fig. 5 is a perspective view of a drive device according to a modified example. Fig. 6 is an exploded perspective view of a drive device according to a modified example. Fig. 7 is a cross-sectional view of a drive device according to a modified example.

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

[0008] Fig. 1 is a perspective view of a drive device 1 according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of the drive device 1. Fig. 3 is a cross-sectional view of the drive device 1 taken along a plane perpendicular to the direction of the rotation axis.

[0009] 1, the drive device 1 includes a power conversion device (inverter device) 10, a motor 20, and a reducer 30. The drive device 1 is mounted on an electric vehicle, and receives a supply of electric power from a battery (not shown) to drive the motor 20, thereby causing the electric vehicle to run.

[0010] The motor 20 drives the electric vehicle by transmitting rotation to the drive wheels via the reduction gear 30. The motor 20 also functions as a generator that generates regenerative power when the electric vehicle decelerates. The reduction gear 30 reduces the rotation of the rotary shaft 22 of the motor 20 and transmits the reduced rotation to the drive wheels.

[0011] As shown in Fig. 2, the inverter device 10, the motor 20, and the reducer 30 are each housed in a housing 40. The housing 40 integrally includes an inverter chamber 41 that houses the inverter device 10, a motor chamber 42 that houses the motor 20, and a reducer chamber 43 that houses the reducer 30. As shown in Fig. 3, the inverter chamber 41 and the motor chamber 42 are arranged side by side in the vertical direction in the housing 40, with the inverter chamber 41 located at the top of the housing 40 and the motor chamber 42 located at the bottom of the housing 40.

[0012] The housing 40 is provided with a refrigerant flow path 70 that allows refrigerant to flow along the inverter device 10 and the motor 20. The housing 40 is composed of an outer housing 26 that forms an inverter chamber 41 and a motor chamber 42, and an inner housing 23 that holds the stator 24 and the rotor 25 inside the motor chamber 42.

[0013] As shown in Fig. 2, the inverter chamber 41 has a box shape with its outer edge surrounded by walls that rise upward. Of the four side surfaces of the box-shaped inverter chamber 41, three are formed by walls that rise from the top of the outer housing 26, and the remaining side surface is formed by an end wall of the inner housing 23, which will be described later. The inverter chamber 41 is sealed by a lid 411 fixed to the upper side surface. The inverter chamber 41 houses the inverter device 10, which has switching elements such as the power module 12.

[0014] The bottom of the inverter chamber 41 is provided with a recess 41a formed to fit the outer shape of the power module 12. The power module 12 is fixed to the bottom of the inverter chamber 41. At this time, a space is formed between the power module 12 and the recess 41a of the inverter chamber 41. This space serves as an inverter flow path 72 for cooling the power module 12 and other components of the inverter device 10, and the inverter flow path 72 constitutes a part of the refrigerant flow path 70. A plurality of fins are formed on the bottom of the power module 12, protruding into the recess 41a (inverter flow path 72). By having the fins protruding into the inverter flow path 72 in this way, the surface area of ​​the bottom of the power module 12 is increased, and heat exchange between the refrigerant and the power module 12 is efficiently carried out.

[0015] The motor chamber 42 is a cylindrical space formed in the axial direction of the outer housing 26. The motor 20 is housed inside the cylindrical inner housing 23, and the inner housing 23 with the motor 20 housed inside is inserted into the motor chamber 42 of the outer housing 26. At this time, a gap is formed between the inner circumferential surface of the outer housing 26 (motor chamber 42) and the outer circumferential surface of the inner housing 23. This gap serves as a motor flow path 74 that circulates refrigerant around the motor 20, and the motor flow path 74 constitutes part of the refrigerant flow path 70.

[0016] When the inner housing 23 is inserted into and fixed to the outer housing 26, the side opening of the outer housing 26 is closed by the end wall of the inner housing 23. At this time, the upper part of the end wall of the inner housing 23 forms part of the wall portion of the outer edge of the inverter chamber 41.

[0017] The motor 20 includes a stator 24 and a rotor 25 rotatably disposed inside the stator 24. The stator 24 is fixed to the inner peripheral surface of an inner housing 23. A rotating shaft 22 is provided at the center of rotation of the rotor 25, and the rotating shaft 22 is connected to a reducer 30 via a gear.

[0018] The reducer chamber 43 is located on the side of the housing 40 and is arranged adjacent to the motor chamber 42. The reducer chamber 43 accommodates the reducer 30. The reducer 30 includes a gear and a differential, as well as a pair of axles (not shown) extending parallel to the rotating shaft 22 of the motor 20. Drive wheels are connected to the axles. The rotation of the motor 20 is transmitted to the reducer 30, and the rotation reduced in the reducer 30 is transmitted to the drive wheels via the axles.

[0019] Next, the coolant flow path 70 of the drive unit 1 configured as above will be described.

[0020] 3, the housing 40 includes an inlet 61 for introducing a refrigerant into a refrigerant flow path 70 formed in the housing 40, and an outlet 62 for discharging the refrigerant from the refrigerant flow path 70. The refrigerant flows through the refrigerant flow path 70 to cool (or warm) the inverter device 10 and the motor 20. Cooling water made of LLC (long life coolant) or the like is used as the refrigerant.

[0021] Generally, the motor and the inverter device generate different amounts of heat and have different target temperatures to which they should be cooled, so simply circulating a refrigerant through the motor and the inverter device within the housing 40 does not necessarily result in cooling them to the appropriate target temperatures.

[0022] Therefore, in this embodiment, the inverter device 10 and the motor 20 are appropriately cooled by the configuration described below.

[0023] As shown in Figure 3, the inlet 61 is fixed so as to communicate with an inlet flow path 71, which is part of the refrigerant flow path 70. The inlet 61 protrudes radially outward from the outer housing 26 at a boundary between the motor chamber 42 and the inverter chamber 41 in the vehicle up-down direction. After protruding from the housing 40, the inlet 61 bends in the axial direction of the motor 20 (see Figure 2) and is connected to a refrigerant pipe (not shown) at this point.

[0024] The inlet flow path 71 is a passage-like space formed inside the housing 40. The inlet flow path 71 is formed between (at the boundary between) the motor chamber 42 and the inverter chamber 41, and extends obliquely upward inside the outer housing 26 toward the bottom of the inverter chamber 41, and then bends upward. The upper end of the inlet flow path 71 communicates with the inverter flow path 72. The refrigerant flowing through the inverter flow path 72 exchanges heat with the power module 12 of the inverter device 10, thereby cooling the power module 12.

[0025] One end (the left end in FIG. 3 ) of the inverter flow path 72 is connected to the inlet flow path 71, and the other end (the right end in FIG. 3 ) of the inverter flow path 72 is connected to the relay flow path 73. The relay flow path 73 is a flow path that constitutes part of the refrigerant flow path 70 and relays the refrigerant discharged from the inverter flow path 72 to the motor flow path 74.

[0026] The relay flow path 73 is a passage-like space that extends vertically from the bottom of the inverter flow path 72 toward the motor chamber 42. The relay flow path 73 has a lower end that opens into the inner wall of the motor chamber 42, thereby communicating with the motor flow path 74. An outlet flow path 75, which is part of the refrigerant flow path 70, also opens into the inner wall of the motor chamber 42. The outlet flow path 75 is formed in the lower part of the outer housing 26 so as to be adjacent to the motor chamber 42.

[0027] 2 , the inner housing 23 is formed with a first wall portion 231 that stands circumferentially along the outer peripheral surface of the inner housing 23 at one end (rear end) in the axial direction (insertion direction into the outer housing 26). A second wall portion 232 that stands circumferentially along the outer peripheral surface of the inner housing 23 is formed at the other end (tip end) of the inner housing 23. The first wall portion 231 and the second wall portion 232 abut against the inner periphery of the motor chamber 42, thereby forming a space surrounded by the inner periphery of the outer housing 26, the outer periphery of the inner housing 23, the first wall portion 231, and the second wall portion 232. This space serves as the motor flow path 74.

[0028] A third wall portion 233 is formed on the outer peripheral surface of the inner housing 23 in a spiral shape that rises in the circumferential direction between the first wall portion 231 and the second wall portion 232. The third wall portion 233 is a partition wall that is provided to prevent the refrigerant flowing from the relay passage 73 into the motor passage 74 from short-circuiting and flowing to the outlet passage 75. The third wall portion 233 is formed on the outer peripheral surface of the inner housing 23 so that the refrigerant that flows from the relay passage 73 into the motor passage 74 flows one and a half times around the motor 20 before heading toward the outlet passage 75, that is, so that the motor passage 74 becomes a spiral passage that follows the outer periphery of the motor 20.

[0029] The outlet flow path 75, which communicates with the downstream portion of the motor flow path 74, has its downstream end communicated with the outlet 62. As shown in Figure 3, the outlet 62 protrudes outward from the right side of the motor chamber 42 at the bottom of the outer housing 26. After protruding from the outer housing 26, the outlet 62 bends in the axial direction. Like the inlet 61, the outlet 62 is connected to a refrigerant pipe (not shown).

[0030] The refrigerant flowing out from the outlet 62 passes through a water pump, a radiator, etc. (not shown), whereby its temperature is reduced. The refrigerant whose temperature has been reduced in this manner is guided to the inlet 61 and flows into the refrigerant flow path 70 again.

[0031] In the refrigerant flow path 70, the cross-sectional area of ​​the inverter flow path 72 in a direction perpendicular to the refrigerant flow direction is smaller than the cross-sectional area of ​​the motor flow path 74 in a direction perpendicular to the refrigerant flow direction. This cross-sectional area in the direction perpendicular to the refrigerant flow direction is defined as the passage area.

[0032] In this way, in the refrigerant flow path 70 of the housing 40, the passage area of ​​the inverter flow path 72 is smaller than the passage area of ​​the motor flow path 74, so that the flow rate of the refrigerant in the inverter flow path 72 can be made faster than the flow rate of the refrigerant in the motor flow path 74.

[0033] Furthermore, the passage area of ​​the relay passage 73 is configured to be larger than the passage area of ​​the inverter passage 72, and the passage area of ​​the motor passage 74 is configured to be the largest among the refrigerant passages 70. This configuration will be described with reference to FIG.

[0034] FIG. 4 is an explanatory diagram showing the configuration of the motor flow passage 74 formed on the outer peripheral surface of the inner housing 23, developed on a two-dimensional plane.

[0035] In the motor flow path 74, the refrigerant flowing in from the relay flow path 73 passes between the first wall portion 231 and the third wall portion 233, then passes between the third wall portion 233 and the second wall portion 232, and flows into the outlet flow path 75. A region (the range indicated by A in FIG. 4 ) where the third wall portion 233 is not formed exists in the flow direction of the motor flow path 74. In this region, there is no third wall portion separating the first wall portion 231 and the second wall portion 232 in the axial direction, and the space between the first wall portion 231 and the second wall portion 232 forms the motor flow path 74. In the motor flow path 74, the passage area of ​​the region not separated by the third wall portion 233 is the largest of the passage areas in the other portions of the refrigerant flow path 70. As a result, the refrigerant flow velocity in this region is the slowest, and the amount (volume) of refrigerant that comes into contact with the outer circumferential surface of the inner housing 23 is also the largest.

[0036] In this way, the flow path area increases stepwise or continuously as it moves toward the inverter flow path 72, the relay flow path 73, and the motor flow path 74, and the passage area of ​​the motor flow path 74 is configured to be the largest, thereby allowing the flow rate of the refrigerant to decrease as it moves toward the motor flow path 74.

[0037] As described above, in this embodiment, the drive device 1 includes the motor flow path 74 that circulates the refrigerant around the motor chamber 42, and the inverter flow path 72 that circulates the refrigerant around the inverter chamber 41 so as to cool the power module 12 included in the inverter device 10. The drive device 1 further includes the inlet flow path 71 that opens to the outside of the housing 40 and allows the refrigerant to flow into the inverter flow path 72, the relay flow path 73 that circulates the refrigerant from the inverter flow path 72 to the motor flow path 74, and the outlet flow path 75 that opens to the outside of the housing 40 and discharges the refrigerant from the motor flow path 74.

[0038] In this configuration, a refrigerant flow path 70 is formed in a housing 40 that integrally accommodates the inverter device 10 and the motor 20. The refrigerant flow path 70 includes an inlet flow path 71, an inverter flow path 72, a relay flow path 73, a motor flow path 74, and an outlet flow path 75, all of which are compactly formed within the single housing 40.

[0039] The refrigerant that flows in from the inlet flow path 71 flows through the inverter flow path 72, relay flow path 73, motor flow path 74, and outlet flow path 75 in that order, exchanging heat with the inverter device 10 and the motor 20 to cool them. In particular, the inverter device 10 having the power module 12 has a lower heat resistance temperature than the motor 20, and needs to be kept at a lower operating temperature than the motor 20. In this embodiment, however, a cooler refrigerant cooled by a radiator or the like flows to the inverter device 10 before the motor 20, making it possible to more appropriately cool the inverter device 10 and the motor 20.

[0040] In this embodiment, the passage area of ​​the inverter passage 72 in the refrigerant passage 70 is smaller than the passage area of ​​the motor passage 74 .

[0041] In this way, because the passage area of ​​the inverter passage 72 is smaller than the passage area of ​​the motor passage 74, the flow rate of the refrigerant passing through the inverter passage 72 is faster than the flow rate of the refrigerant passing through the motor passage 74. This makes it possible to improve the heat exchange efficiency in the inverter passage 72. Meanwhile, the motor 20 has a larger volume and a larger thermal time constant (heat capacity) than the inverter device 10. Therefore, by relatively slowing down the flow rate of the refrigerant in the motor passage 74, the time for heat exchange between the refrigerant and the motor 20 can be increased, and even the refrigerant that has passed through the inverter passage 72 can sufficiently cool the motor 20.

[0042] In this embodiment, the passage area of ​​the relay passage 73 is configured to be larger than the passage area of ​​the inverter passage 72 , while the passage area of ​​the motor passage 74 is configured to be the largest among the refrigerant passages 70 .

[0043] With this configuration, the flow rate of the refrigerant can be gradually slowed as it passes through the inverter flow path 72, the relay flow path 73, and the motor flow path 74, and the flow rate of the refrigerant in the motor flow path 74 can be sufficiently reduced to a desired flow rate. This makes it possible for the refrigerant, whose temperature has increased after passing through the inverter flow path 72 and the relay flow path 73, to be able to sufficiently cool the motor 20. Furthermore, because the passage area of ​​the motor flow path 74 is configured to be the largest among the refrigerant flow paths 70, the flow rate of the refrigerant that comes into contact with the motor 20 is small and the amount (volume) of the refrigerant is the largest, thereby more appropriately cooling the motor 20.

[0044] In this embodiment, the housing 40 includes an outer housing 26 and an inner housing 23 that houses the motor 20 and is inserted into the outer housing 26. A motor flow path 74 is formed between the inner peripheral surface of the outer housing 26 and the outer peripheral surface of the inner housing 23. The inner housing 23 includes a first wall portion 231 that is circumferentially formed along the outer peripheral surface at one axial end of the inner housing 23, a second wall portion 232 that is circumferentially formed along the outer peripheral surface at the other axial end, and a third wall portion 233 that separates the first wall portion 231 and the second wall portion 232 and is spirally formed on the outer peripheral surface.

[0045] In this configuration, the refrigerant flowing through the motor flow path 74 flows circumferentially around the motor 20 due to the third wall portion 233 formed between the first wall portion 231 and the second wall portion 232 before flowing toward the outlet, so that a sufficient amount (volume) of refrigerant can flow around the motor 20 with a simple structure. This allows the motor 20 to be cooled more appropriately.

[0046] Next, a modification of this embodiment will be described with reference to FIGS.

[0047] Fig. 5 is a perspective cross-sectional view of a drive device 1 according to a modified example of the present embodiment. Fig. 6 is an exploded perspective view of a housing 40 of the modified drive device 1. Fig. 7 is a cross-sectional view of the modified drive device 1 taken along a plane perpendicular to the rotation axis direction.

[0048] 5 , in the drive system 1 of the modified example, the inverter device 10 is disposed below the motor 20. That is, in the outer housing 26 that constitutes the housing 40, a motor chamber 42 and an inverter chamber 41 are arranged side by side in the vertical direction of the vehicle. The inverter chamber 41 is located in the lower part of the outer housing 26, and the motor chamber 42 is located in the upper part of the outer housing 26.

[0049] 7, the inverter chamber 41 is provided in the lower part of the outer housing 26 and has a box shape surrounded by a wall portion that extends downward at its outer edge. The inverter chamber 41 is sealed from below by a lid portion 411. The inverter chamber 41 accommodates the inverter device 10 having switching elements such as the power module 12.

[0050] The upper bottom of the inverter chamber 41 is provided with a recess 41a formed to fit the outer shape of the power module 12. A space is formed between the power module 12 and the recess 41a of the inverter chamber 41, and this space serves as an inverter flow path 72 for cooling the power module 12 and the like of the inverter device 10.

[0051] As shown in Figure 6, an inlet 61 is fixed to the lower part of the outer housing 26 of the housing 40. An inlet flow path 71 communicating with the inlet 61 is formed inside the outer housing 26 and is configured to extend in the axial direction and then bend in the radial direction. The downstream end of the inlet flow path 71 communicates with an inverter flow path 72.

[0052] The lower end of a relay flow path 73 is connected to the end of the inverter flow path 72. The relay flow path 73 is a linear passage extending in the vertical direction, and the upper end of the relay flow path 73 is connected to a motor flow path 74. The refrigerant that has passed through the inverter flow path 72 is guided to the motor flow path 74 via the relay flow path 73.

[0053] The refrigerant that has flowed into the motor flow path 74 flows along the third wall portion 233 around the motor 20 in a clockwise direction for one and a half revolutions before heading toward the outlet flow path 75 .

[0054] The outlet flow passage 75 is formed inside the outer housing 26. The outlet flow passage 75 extends radially from the motor chamber 42 and communicates with the outlet 62 fixed to the upper part of the outer housing 26. The refrigerant that flows into the outlet flow passage 75 is discharged from the flow passage through the outlet 62 to the outside.

[0055] In this way, even if the inverter device 10 is arranged below the motor 20, a lower temperature refrigerant cooled by a radiator or the like flows to the inverter device 10 before the motor 20, thereby allowing the inverter device 10 and the motor 20 to be properly cooled.

[0056] In particular, by arranging the inverter device 10, which has a lower heat resistance temperature than the motor 20, below the motor 20, the inverter device 10 is less susceptible to the effects of heat generated by the motor 20. This makes it possible to more appropriately cool the inverter device 10 and the motor 20.

[0057] The above describes embodiments of the present invention and their modifications. However, the above embodiments and modifications merely illustrate some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0058] The housing 40 of the drive unit 1 is configured to integrally include a reducer chamber 43 that houses the reducer 30, but it is not necessary to include this reducer chamber 43. Also, the drive unit 1 is configured to include the reducer 30, but is not limited to a reducer, and may include a speed change mechanism such as a speed increaser.

Claims

1. A drive device integrally comprising a motor accommodated in a motor chamber of a housing and an inverter device accommodated in an inverter chamber of the housing, wherein the housing comprises: a motor flow path for circulating a refrigerant around the motor chamber; an inverter flow path for circulating a refrigerant around the inverter chamber to cool a power module of the inverter device; an inlet flow path that opens to the outside of the housing and allows the refrigerant to flow into the inverter flow path; a relay flow path that circulates the refrigerant from the inverter flow path to the motor flow path; and an outlet flow path that opens to the outside of the housing and discharges the refrigerant from the motor flow path.

2. A drive device according to claim 1, wherein the cross-sectional area of ​​the inverter flow path in a direction perpendicular to the refrigerant flow direction is smaller than the cross-sectional area of ​​the motor flow path.

3. A drive device according to claim 2, wherein the cross-sectional area of ​​the relay flow path in a direction perpendicular to the refrigerant flow direction is larger than the cross-sectional area of ​​the inverter flow path and smaller than the cross-sectional area of ​​the motor flow path.

4. A drive device as claimed in claim 1, wherein the housing comprises an outer housing and an inner housing that houses the motor and is inserted into the outer housing, the motor flow path is formed between the inner peripheral surface of the outer housing and the outer peripheral surface of the inner housing, and the inner housing comprises: a first wall portion formed circumferentially along the outer peripheral surface at one axial end of the inner housing; a second wall portion formed circumferentially along the outer peripheral surface at the other axial end; and a third wall portion that separates the first wall portion from the second wall portion and is formed spirally on the outer peripheral surface.

5. A drive device according to claim 4, wherein the motor flow path has an area between the first wall portion and the second wall portion in the direction of refrigerant flow where the third wall portion is not formed.

6. A drive device according to any one of claims 1 to 5, wherein the drive device is mounted on a vehicle, the housing has the motor chamber and the inverter chamber arranged in the vertical direction, the inverter chamber being located in the lower part of the housing, and the motor chamber being located in the upper part of the housing.

7. A drive device according to any one of claims 1 to 5, wherein the drive device is mounted on a vehicle, the housing has the motor chamber and the inverter chamber arranged in the vertical direction, the inverter chamber being located in the upper part of the housing, and the motor chamber being located in the lower part of the housing.

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