Drive unit

Abstract

To cool two electric motors even when an abnormality occurs in one of two oil pumps.SOLUTION: A drive apparatus includes: a first electric motor that drives a left wheel of a vehicle; a second electric motor that drives a right wheel of the vehicle; a first oil pump that supplies oil to the first electric motor via a first oil supply passage; a second oil pump that supplies oil to the second electric motor via a second oil supply passage; a connection flow passage that connects the first oil supply passage and the second oil supply passage; and a flow regulation device that is installed in the connection flow passage and allows oil to flow through the connection flow passage when one of the first oil pump and the second oil pump is abnormal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to a driving device.

[0002] Patent Document 1 discloses an electric vehicle that drives a left wheel and a right wheel with separate electric motors. The driving device of this electric vehicle has a first electric motor and a second electric motor. The driving force of the first electric motor is transmitted to the left wheel, and the driving force of the second electric motor is transmitted to the right wheel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric vehicle, an oil pump for supplying oil to an electric motor is provided. By supplying oil to the electric motor, the electric motor is cooled. In a driving device having a first electric motor and a second electric motor, a first oil pump for supplying oil to the first electric motor and a second oil pump for supplying oil to the second electric motor can be provided independently. When the first oil pump and the second oil pump are provided in this way, the flow rate of the oil supplied to the first electric motor and the flow rate of the oil supplied to the second electric motor can be controlled individually. Therefore, the temperature of the first electric motor and the temperature of the second electric motor can be appropriately controlled.

[0005] In a driving device having a first oil pump and a second oil pump, when an abnormality occurs in one of the two oil pumps, it becomes difficult to cool the electric motor corresponding to the oil pump in which the abnormality has occurred. In this specification, a technology that enables cooling of two electric motors even when an abnormality occurs in one of the two oil pumps is proposed.

Means for Solving the Problems

[0006] The drive system disclosed herein includes a first electric motor for driving the left wheel of a vehicle, a second electric motor for driving the right wheel of the vehicle, a first oil pump for supplying oil to the first electric motor via a first oil supply passage, a second oil pump for supplying oil to the second electric motor via a second oil supply passage, a connecting passage for connecting the first oil supply passage and the second oil supply passage, and a flow rate regulator installed in the connecting passage which allows oil to flow into the connecting passage in the event of a malfunction in either the first oil pump or the second oil pump.

[0007] The flow rate control device can be any device that allows oil to flow into the connecting passage when either the first oil pump or the second oil pump malfunctions. For example, the flow rate control device may be a valve that opens the connecting passage when either the first oil pump or the second oil pump malfunctions. Alternatively, the flow rate control device may be a component with high flow resistance. In this case, when either the first oil pump or the second oil pump malfunctions, a pressure difference will be created on both sides of the flow rate control device, causing oil to flow into the connecting passage.

[0008] In this drive system, the first oil supply passage and the second oil supply passage are connected by a connecting passage. When both the first and second oil pumps are operating normally, almost no oil flows through the connecting passage. Therefore, in this case, oil is supplied from the first oil pump to the first motor via the first oil supply passage, and oil is supplied from the second oil pump to the second motor via the second oil supply passage. When the first oil pump malfunctions, it is permissible for oil to flow through the connecting passage. Therefore, in this case, a portion of the oil discharged by the second oil pump is supplied to the first motor via the second oil supply passage, the connecting passage, and the first oil supply passage. As a result, both the first and second motors are cooled by the oil discharged by the second oil pump. When the second oil pump malfunctions, it is permissible for oil to flow through the connecting passage. Therefore, in this case, a portion of the oil discharged by the first oil pump is supplied to the second motor via the first oil supply passage, the connecting passage, and the second oil supply passage. Therefore, both the first and second electric motors are cooled by the oil discharged by the first oil pump. In this way, with this drive system, even if a malfunction occurs in one of the two oil pumps, both electric motors will be cooled. [Brief explanation of the drawing]

[0009] [Figure 1] A cross-sectional view of the drive mechanism along the left-right direction. [Figure 2] Cross-sectional view of the drive mechanism along line AA in Figure 1. [Figure 3] A flowchart showing the processes executed by the control device 70. [Modes for carrying out the invention]

[0010] The following are additional features of the drive system disclosed herein.

[0011] The flow rate control device may be located in the center of the connecting flow path.

[0012] This configuration prevents an imbalance in the resistance distribution of the communication channel.

[0013] The drive system may further include a first gear set that transmits the driving force of the first electric motor to the left wheel, a second gear set that transmits the driving force of the second electric motor to the right wheel, and a gear housing chamber that houses the first gear set and the second gear set. Oil that has passed through the first electric motor may flow into the gear housing chamber, and oil that has passed through the second electric motor may flow into the gear housing chamber. The chamber housing the first gear set and the chamber housing the second gear set may be connected to each other, or they may be separated by a partition wall.

[0014] With this configuration, the gears can be lubricated by the oil that has passed through the electric motor.

[0015] The flow rate control device may also be an orifice.

[0016] The flow rate control device may be a valve. The system may further include a valve control device that opens the valve in the event of a malfunction in either the first oil pump or the second oil pump.

[0017] The drive unit may further include an oil pump control device that increases the output of the other oil pump when either the first oil pump or the second oil pump malfunctions.

[0018] The drive unit may further include an electric motor control device that reduces the output of the first electric motor and the second electric motor in the event of a malfunction in either the first oil pump or the second oil pump.

[0019] The motor control device may control the amount of output reduction of the first motor and the amount of output reduction of the second motor according to the temperature of the drive unit.

[0020] The motor control device may reduce the output of the first motor and the output of the second motor by the same ratio. [Examples]

[0021] The drive device 10 of the embodiment shown in FIG. 1 is mounted on an electric vehicle. In FIG. 1, the arrow FR indicates the front direction of the vehicle, and the arrow RH indicates the right direction of the vehicle. The drive device 10 drives the left rear wheel 90 and the right rear wheel 92 of the electric vehicle.

[0022] The drive device 10 has a case 12. Inside the case 12, a left motor chamber 13, a left gear chamber 14, a right motor chamber 15, and a right gear chamber 16 are provided. The left gear chamber 14 is arranged behind the left motor chamber 13. The right motor chamber 15 is arranged on the right side of the left motor chamber 13. The right gear chamber 16 is arranged behind the right motor chamber 15. In FIG. 1, the left gear chamber 14 and the right gear chamber 16 are connected, but the left gear chamber 14 and the right gear chamber 16 may be separated by a partition wall. The left motor 20 is accommodated in the left motor chamber 13. In the left gear chamber 14, a gear set for transmitting the driving force of the left motor 20 to the left rear wheel 90 is accommodated. The right motor 40 is accommodated in the right motor chamber 15. In the right gear chamber 16, a gear set for transmitting the driving force of the right motor 40 to the right rear wheel 92 is accommodated.

[0023] The left motor 20 has a rotor 20a and a stator 20b. The rotor 20a has a shaft 20c. The rotor 20a is accommodated in the left motor chamber 13 in a direction in which the shaft 20c extends along the front-rear direction of the electric vehicle. The rotor 20a is rotatably supported by a bearing (not shown) provided on the case 12. The shaft 20c penetrates the partition wall between the left motor chamber 13 and the left gear chamber 14 and extends from the left motor chamber 13 to the left gear chamber 14. The stator 20b is arranged around the rotor 20a. By flowing an electric current through the stator 20b, the rotor 20a rotates.

[0024] The gear set located in the left gear chamber 14 includes gears 22, 23, 24, and 25. Also located in the left gear chamber 14 are a countershaft 26 and a drive shaft 27. The countershaft 26 is positioned parallel to the shaft 20c of the rotor 20a. The countershaft 26 is rotatably supported by bearings (not shown) provided in the case 12. The drive shaft 27 extends along the left-right direction of the electric vehicle. The drive shaft 27 extends from the left gear chamber 14, through the left side wall of the case 12, to the outside of the case 12. The left rear wheel 90 is connected to the left end of the drive shaft 27. The drive shaft 27 is rotatably supported by bearings (not shown) provided in the case 12. Gear 22 is a cylindrical gear fixed to the shaft 20c of the rotor 20a. Gear 23 is a cylindrical gear fixed to the countershaft 26. Gear 23 engages with gear 22. Gear 24 is a frustoconical gear and is fixed to the countershaft 26. Gear 25 is a frustoconical gear and is fixed to the drive shaft 27. Gear 25 engages with gear 24. Gears 24 and 25 constitute a hypoid gear.

[0025] When the left electric motor 20 is driven, the shaft 20c of the rotor 20a rotates, causing gear 22 to rotate, and the driving force is transmitted from gear 22 to gear 23. As a result, gear 23, countershaft 26, and gear 24 rotate. When gear 24 rotates, the driving force is transmitted from gear 24 to gear 25. As a result, gear 25 and drive shaft 27 rotate. Consequently, the left rear wheel 90 rotates. In this way, the gear set in the left gear chamber 14 transmits the driving force of the left electric motor 20 to the left rear wheel 90.

[0026] As shown in Figure 2, the bottom surface of the left gear chamber 14 is positioned lower than the bottom surface of the left motor chamber 13. Oil 80 is stored in the left gear chamber 14 at a level sufficient to submerge the lower part of the gear 25. Therefore, when the gear 25 rotates due to the drive of the left motor 20, the oil 80 stored in the left gear chamber 14 is splashed up by the gear 25. This causes the oil to be sprayed into the left gear chamber 14. Each gear is lubricated by the oil sprayed into the left gear chamber 14.

[0027] The drive unit 10 has a left oil circulation path that circulates oil to the left motor chamber 13 and the left gear chamber 14. The left oil circulation path includes an oil pump 30, an oil supply path 31, a shaft passage 32, an oil passage 33, an oil outlet 34, and an oil discharge path 35. The oil supply path 31 is composed of piping on the outside of the case 12 and a passage provided inside the outer wall of the case 12. The shaft 20c of the rotor 20a has a cylindrical shape, and the shaft passage 32 is formed by its central hole. The shaft passage 32 extends from the front end to the rear end of the shaft 20c. The oil supply path 31 connects the discharge port of the oil pump 30 to the front end of the shaft passage 32. Multiple oil dispersal passages 32a are provided on the outer circumferential wall of the shaft 20c. The oil passage 33 penetrates the partition wall between the left motor chamber 13 and the left gear chamber 14. The oil discharge port 34 opens to the bottom surface of the left gear chamber 14. The oil discharge passage 35 is formed by piping outside the case 12. The oil discharge passage 35 connects the oil outlet 34 to the suction port of the oil pump 30.

[0028] When the oil pump 30 operates, the oil 80 stored in the left gear chamber 14 is drawn into the oil outlet 34. The oil drawn into the oil outlet 34 is supplied to the shaft passage 32 through the oil outlet 35, the oil pump 30, and the oil supply passage 31. Within the shaft passage 32, the oil flows from the front end to the rear end. The oil that has flowed through the shaft passage 32 to the rear end is discharged into the left gear chamber 14. In addition, a portion of the oil flowing through the shaft passage 32 is sprayed into the left motor chamber 13 from the oil spray passage 32a. The left motor 20 is cooled by the oil flowing through the shaft passage 32 and the oil sprayed into the left motor chamber 13. The rotor 20a is also lubricated by the oil sprayed into the left motor chamber 13. The oil sprayed into the left motor chamber 13 flows to the left gear chamber 14 through the oil passage 33. In this way, when the oil pump 30 operates, oil circulates in the left oil circulation path, and the left electric motor 20 is cooled.

[0029] The structure inside the right motor chamber 15 and the right gear chamber 16 is the same as the structure inside the left motor chamber 13 and the left gear chamber 14, but reversed left and right. The right motor 40 has a rotor 40a and a stator 40b. The rotor 40a has a shaft 40c. The rotor 40a is housed in the right motor chamber 15 with the shaft 40c extending along the longitudinal direction of the electric vehicle. The rotor 40a is rotatably supported by bearings (not shown) provided in the case 12. The shaft 40c penetrates the partition wall between the right motor chamber 15 and the right gear chamber 16 and extends from the right motor chamber 15 to the right gear chamber 16. The stator 40b is arranged around the rotor 40a. By passing current through the stator 40b, the rotor 40a rotates.

[0030] The gear set located in the right gear chamber 16 includes gears 42, 43, 44, and 45. Also located in the right gear chamber 16 are a countershaft 46 and a drive shaft 47. The countershaft 46 is positioned parallel to the shaft 40c of the rotor 40a. The countershaft 46 is rotatably supported by bearings (not shown) provided in the case 12. The drive shaft 47 extends along the left-right direction of the electric vehicle. The drive shaft 47 extends from the right gear chamber 16, through the right side wall of the case 12, to the outside of the case 12. The right rear wheel 92 is connected to the right end of the drive shaft 47. The drive shaft 47 is rotatably supported by bearings (not shown) provided in the case 12. Gear 42 is a cylindrical gear fixed to the shaft 40c of the rotor 40a. Gear 43 is a cylindrical gear fixed to the countershaft 46. Gear 43 engages with gear 42. Gear 44 is a conical gear fixed to the countershaft 46. Gear 45 is a conical gear fixed to the drive shaft 47. Gear 45 engages with gear 44. Gears 44 and 45 constitute a hypoid gear.

[0031] When the right electric motor 40 is driven, the shaft 40c rotates, and the driving force is transmitted from the shaft 40c to the drive shaft 47 via the gears 42, 43, 44, and 45. As a result, the drive shaft 47 rotates, and the right rear wheel 92 rotates. In this way, the gear set in the right gear chamber 16 transmits the driving force of the right electric motor 40 to the right rear wheel 92.

[0032] Similar to Figure 2, the bottom surface of the right gear chamber 16 is positioned lower than the bottom surface of the right motor chamber 15. Oil is stored in the right gear chamber 16 at a level sufficient to submerge the lower part of the gear 45. Therefore, when the gear 45 rotates due to the drive of the right motor 40, the oil stored in the right gear chamber 16 is splashed up by the gear 45. This causes oil to be sprayed into the right gear chamber 16. Each gear is lubricated by the oil sprayed into the right gear chamber 16.

[0033] The drive unit 10 has a right oil circulation path that circulates oil to the right motor chamber 15 and the right gear chamber 16. The right oil circulation path includes an oil pump 50, an oil supply path 51, a shaft passage 52, an oil passage 53, an oil outlet 54, and an oil discharge path 55. The oil supply path 51 is composed of piping on the outside of the case 12 and a passage provided inside the outer wall of the case 12. The shaft 40c of the rotor 40a has a cylindrical shape, and the shaft passage 52 is formed by its central hole. The shaft passage 52 extends from the front end to the rear end of the shaft 40c. The oil supply path 51 connects the discharge port of the oil pump 50 to the front end of the shaft passage 52. Multiple oil dispensing passages 52a are provided on the outer circumferential wall of the shaft 40c. The oil passage 53 penetrates the partition wall between the right motor chamber 15 and the right gear chamber 16. The oil outlet 54 opens to the bottom surface of the right gear chamber 16. The oil discharge passage 55 is formed by piping on the outside of the case 12. The oil discharge passage 55 connects the oil outlet 54 to the suction port of the oil pump 50.

[0034] When the oil pump 50 operates, oil stored in the right gear chamber 16 is supplied to the shaft passage 52 through the oil outlet 54, oil discharge passage 55, oil pump 50, and oil supply passage 51. The oil that flows through the shaft passage 52 from the front to the rear is discharged into the right gear chamber 16. In addition, a portion of the oil flowing through the shaft passage 52 is sprayed into the right motor chamber 15 from the oil spray passage 52a. The right motor 40 is cooled by the oil flowing through the shaft passage 52 and the oil sprayed into the right motor chamber 15. The rotor 40a is also lubricated by the oil sprayed into the right motor chamber 15. The oil sprayed into the right motor chamber 15 flows to the right gear chamber 16 through the oil passage 53. In this way, when the oil pump 50 operates, oil circulates in the right oil circulation passage, and the right motor 40 is cooled.

[0035] Inside the outer wall of case 12, a connecting passage 60 is provided that connects the oil supply passage 31 and the oil supply passage 51. A flow rate regulator 62 is installed in the center of the connecting passage 60. In Embodiment 1, the flow rate regulator 62 is an orifice. Therefore, the flow resistance of the connecting passage 60 is greater than the flow resistance of the oil supply passage 31 and the flow resistance of the oil supply passage 51.

[0036] The drive unit 10 has a control device 70 that controls the oil pumps 30 and 50. Figure 3 shows the process performed by the control device 70. The control device 70 repeatedly performs the process shown in Figure 3 while the electric vehicle is running.

[0037] (Operation when oil pumps 30 and 50 are normal) In step S2, the control device 70 determines whether both oil pumps 30 and 50 are normal. If both oil pumps 30 and 50 are normal, the control device 70 operates oil pumps 30 and 50 in step S4. As long as both oil pumps 30 and 50 are normal, steps S2 and S4 are repeatedly executed, and oil pumps 30 and 50 continue to operate. When oil pumps 30 and 50 are operating normally, the pressure in the oil supply passage 31 and the pressure in the oil supply passage 51 are both high, and no large pressure difference occurs between the oil supply passage 31 and the oil supply passage 51. As a result, almost no oil flows through the connecting passage 60, which has high flow resistance. Therefore, the oil discharged by oil pump 30 is supplied to the left motor 20, and the oil discharged by oil pump 50 is supplied to the right motor 40. As a result, the left motor 20 and the right motor 40 are properly cooled. In this case, the control device 70 independently controls the outputs of the oil pumps 30 and 50. That is, it controls the output of oil pump 30 according to the state of the left motor 20, and controls the output of oil pump 50 according to the state of the right motor 40. In this way, since the control device 70 independently controls the outputs of oil pump 30 and oil pump 50, the temperatures of the left motor 20 and the right motor 40 are appropriately controlled.

[0038] (Operation when one of the oil pumps 30 or 50 is abnormal) If an abnormality occurs in the oil pumps 30 or 50 while the electric vehicle is running, the control device 70 determines NO in step S2. Then, in step S6, the control device 70 determines whether only one of the oil pumps 30 or 50 is abnormal, or whether both oil pumps 30 and 50 are abnormal. If only one of the oil pumps 30 or 50 is abnormal, the control device 70 stops the abnormal oil pump in step S8.

[0039] If the oil pump 30 is stopped due to a malfunction, the pressure in the oil supply passage 31 decreases. As a result, the pressure in the oil supply passage 51 becomes higher than the pressure in the oil supply passage 31, and some of the oil in the oil supply passage 51 flows to the oil supply passage 51 through the connecting passage 60. The oil that flows to the oil supply passage 51 through the connecting passage 60 flows to the shaft passage 32 of the left electric motor 20. This cools the left electric motor 20. In this way, if a malfunction occurs in the oil pump 30, the oil discharged by the oil pump 50 is supplied to the left electric motor 20 and the right electric motor 40, suppressing the temperature rise of the left electric motor 20 and the right electric motor 40. Also, if the oil pump 50 is stopped due to a malfunction, some of the oil discharged by the oil pump 30 is supplied to the right electric motor 40 through the connecting passage 60. In other words, if a malfunction occurs in the oil pump 50, the oil discharged by the oil pump 30 is supplied to the left electric motor 20 and the right electric motor 40, suppressing the temperature rise of the left electric motor 20 and the right electric motor 40. In this way, even if a malfunction occurs in either the oil pump 30 or 50, the left motor 20 and the right motor 40 will still be cooled.

[0040] Furthermore, the flow rate regulator 62 (i.e., the orifice) is located in the center of the connecting flow path 60. Therefore, the flow resistance of the connecting flow path 60 is approximately equal whether oil flows towards the oil supply path 51 or in the opposite direction. Consequently, even if either the oil pump 30 or 50 stops, the electric motors 20 and 40 can be adequately cooled.

[0041] Next, in step S10, the control device 70 increases the output of the normal oil pump. This compensates for the reduced cooling performance caused by the shutdown of one of the oil pumps. Next, in step S12, the control device 70 determines whether it is necessary to limit the output of the left motor 20 and the right motor 40. If the output command values ​​for the left motor 20 and the right motor 40 are too large relative to the cooling performance of the oil pump, the control device 70 determines YES in step S12. If YES in step S12, the control device 70 limits the output of the left motor 20 and the right motor 40 in step S14. This prevents the left motor 20 and the right motor 40 from overheating. In step S14, the control device 70 reduces the output of the left motor 20 and the right motor 40 by the same proportion. This prevents the output of the left motor 20 and the right motor 40 from becoming unbalanced and changing the direction of travel of the electric vehicle. Furthermore, in step S14, the control device 70 may control the amount of output reduction of the left motor 20 and the right motor 40 according to the temperature of the drive unit 10 (for example, the internal temperature of the drive unit 10 or the temperature of the circulating oil). This minimizes the amount of output reduction of the left motor 20 and the right motor 40. If the answer in step S12 is NO (i.e., output limiting of the left motor 20 and the right motor 40 is not necessary), the control device 70 controls the left motor 20 and the right motor 40 at their normal output in step S18.

[0042] (Operation when both oil pumps 30 and 50 are abnormal) If both oil pumps 30 and 50 are abnormal, the control device 70 determines NO in step S6 and stops both oil pumps 30 and 50 in step S16. Subsequently, the control device 70 controls the left motor 20 and the right motor 40 in steps S12, S14, and S18.

[0043] As described above, in the drive unit 10 of Example 1, if an abnormality occurs in one of the oil pumps 30 or 50, the oil discharged by the normal oil pump can be supplied to both the left motor 20 and the right motor 40. This allows the left motor 20 and the right motor 40 to be cooled. [Examples]

[0044] In Embodiment 2, the flow rate control device 62 is composed of an on-off valve that opens and closes the connecting passage. The flow rate control device 62 is controlled by the control device 70. In Embodiment 2, when both oil pumps 30 and 50 are functioning normally, the control device 70 controls the flow rate control device 62 to the closed state. In this case, the oil discharged by oil pump 30 is supplied to the left motor 20, and the oil supplied by oil pump 50 is supplied to the right motor 40. If either oil pump 30 or 50 is malfunctioning, the control device 70 controls the flow rate control device 62 to the open state. This allows oil to flow into the connecting passage 60. As a result, the oil discharged by a normal oil pump is supplied to both the left motor 20 and the right motor 40, and both the left motor 20 and the right motor 40 are cooled. In this way, even if one of the two oil pumps 30 or 50 malfunctions, the left motor 20 and the right motor 40 can still be cooled.

[0045] In the above-described embodiments 1 and 2, the gear chambers 14 and 16 functioned as oil storage chambers for storing oil supplied to the oil pumps 30 and 50. However, an oil storage chamber separate from the gear chambers 14 and 16 may also be provided.

[0046] Furthermore, in the above-described embodiments 1 and 2, the electric motor was cooled by the oil discharged by the oil pump flowing inside the rotor shaft. However, the oil may be supplied to the electric motor from the oil pump in any form as long as the electric motor can be cooled. For example, the oil may be discharged from the oil supply passage toward the outer surface of the rotor.

[0047] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness. [Explanation of symbols]

[0048] 10: Drive unit, 20: Left motor, 22-25: Gears, 30: Oil pump, 31: Oil supply passage, 40: Right motor, 42-45: Gears, 50: Oil pump, 51: Oil supply passage, 60: Connecting passage, 62: Flow rate regulator

Claims

1. A drive device, The first electric motor drives the left wheel of the vehicle, A second electric motor that drives the right wheel of the aforementioned vehicle, A first oil pump that supplies oil to the first electric motor via a first oil supply passage, A second oil pump that supplies oil to the second electric motor via a second oil supply passage, A connecting passage that connects the first oil supply passage and the second oil supply passage, A flow rate control device is installed in the connecting passage and allows oil to flow into the connecting passage when either the first oil pump or the second oil pump malfunctions, A first gear set that transmits the driving force of the first electric motor to the left wheel, A second gear set that transmits the driving force of the second electric motor to the right wheel, A gear housing chamber that houses the first gear set and the second gear set, It has, The oil that has passed through the first electric motor flows into the gear housing chamber. The oil that has passed through the second electric motor flows into the gear housing chamber. Drive unit.

2. The drive device according to claim 1, wherein the flow rate control device is located in the center of the connecting flow path.

3. A drive device, The first electric motor drives the left wheel of the vehicle, A second electric motor that drives the right wheel of the aforementioned vehicle, A first oil pump that supplies oil to the first electric motor via a first oil supply passage, A second oil pump that supplies oil to the second electric motor via a second oil supply passage, A connecting passage that connects the first oil supply passage and the second oil supply passage, A flow rate control device installed in the connecting passage, which allows oil to flow into the connecting passage when either the first oil pump or the second oil pump malfunctions. It has, A drive device in which the flow rate control device is an orifice.

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