Drive device

Abstract

This drive device is provided with a plurality of rotating electrical machines, a plurality of power conversion devices, and a plurality of refrigerant paths provided in parallel with each other and for cooling the plurality of rotating electrical machines and the plurality of power conversion devices. The plurality of power conversion devices are electrically connected to at least one of the plurality of rotating electrical machines, respectively. Each of the plurality of refrigerant paths is configured to cool at least one of the plurality of power conversion devices and at least one of the plurality of rotating electrical machines. Each of the plurality of rotating electrical machines is electrically connected to a power conversion device different from at least one power conversion device that is cooled by the same refrigerant path.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a drive device. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2018-121429 discloses a vehicle having a plurality of rotating electric motors and a plurality of power conversion devices. In the vehicle, the rotating electric motors and the power conversion devices that are electrically connected to each other are cooled by the same refrigerant path.

[0003] Generally, the same current flows through a rotating electric motor and a power conversion device electrically connected thereto. Therefore, when one of the plurality of rotating electric motors operates at a high load, both the rotating electric motor and the power conversion device electrically connected thereto generate a large amount of heat. At this time, according to the technology of Japanese Unexamined Patent Application Publication No. 2018-121429, these rotating electric motors and power conversion devices are cooled by the same refrigerant path. As a result, a large difference in the required cooling amount occurs between this refrigerant path and other refrigerant paths, and the cooling efficiency is reduced. In this specification, a technology capable of improving the cooling efficiency in a drive device is provided. Summary of the Invention

[0004] The drive device according to the first aspect of the present disclosure includes: a plurality of rotating electric motors; a plurality of power conversion devices; and a plurality of refrigerant paths configured to be provided in parallel with each other and to cool the plurality of rotating electric motors and the plurality of power conversion devices. Each of the plurality of power conversion devices is electrically connected to at least one of the plurality of rotating electric motors. Each of the plurality of refrigerant paths is configured to cool at least one of the plurality of power conversion devices and at least one of the plurality of rotating electric motors. Each of the plurality of rotating electric motors is electrically connected to a power conversion device different from the at least one power conversion device that is cooled by the same refrigerant path as itself.

[0005] In the drive device described above, the rotating electric motor and the power conversion device that are electrically connected are not cooled by the same refrigerant path. For example, even if one of the plurality of rotating electric motors and the power conversion device connected to the rotating electric motor generate heat, these rotating electric motor and power conversion device are cooled by mutually different refrigerant paths. As a result, for the plurality of refrigerant paths, it is possible to equalize the required cooling amount, and thus it is possible to expect an improvement in the cooling efficiency in the drive device.

[0006] Details of the technology disclosed in this specification and further improvements are described in the following "Detailed Description".

[0007] Hereinafter, with reference to the drawings, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described. In the drawings, the same reference numerals denote the same elements. Brief Description of the Drawings

[0008] Figure 1 A block diagram showing an electric vehicle equipped with the drive device 20 of the first embodiment.

[0009] Figure 2 A circuit diagram showing the drive device 20 of the first embodiment.

[0010] Figure 3 Indicates along Figure 1 A cross-sectional view taken along line III-III.

[0011] Figure 4 Indicates the same cross-sectional view in the drive device 120 of the second embodiment as that of Figure 3 the same.

[0012] Figure 5 Indicates the same cross-sectional view in the drive device 220 of the third embodiment as that of Figure 3 the same.

[0013] Figure 6 Indicates the same cross-sectional view in the drive device 320 of the fourth embodiment as that of Figure 3 the same. Detailed implementation manners

[0014] It can also be configured that, based on the drive device related to the first technical solution of the present disclosure, the above-mentioned plurality of rotating motors include a first rotating motor and a second rotating motor. The above-mentioned plurality of power conversion devices may also include a first power conversion device electrically connected to the above-mentioned first rotating motor and a second power conversion device electrically connected to the above-mentioned second rotating motor. And the above-mentioned plurality of refrigerant paths may also include: a first refrigerant path configured to cool the above-mentioned first power conversion device and the above-mentioned second rotating motor; and a second refrigerant path configured to cool the above-mentioned second power conversion device and the above-mentioned first rotating motor. Among them, in another embodiment, the plurality of rotating motors may also include three or more rotating motors. In this case, the plurality of power conversion devices may also include three or more power conversion devices, and the plurality of refrigerant paths may also include three or more refrigerant paths.

[0015] The drive device related to the first technical solution of the present disclosure may also further include: a first oil cooler configured to cool the above-mentioned first rotating motor; and a first oil pump configured to supply oil to the above-mentioned first rotating motor via the above-mentioned first oil cooler. The above-mentioned second refrigerant path may also be configured to cool the oil in the above-mentioned first oil cooler.

[0016] According to such a structure, the first rotating motor can be cooled by oil, and the rotation of the first rotating motor can be made smooth.

[0017] The drive device according to the first aspect of the present disclosure may further include: a second oil cooler configured to cool the second rotating electric machine; and a second oil pump configured to supply oil to the second rotating electric machine via the second oil cooler. The first refrigerant path may also be configured to cool the oil in the second oil cooler.

[0018] According to such a configuration, the second rotating electric machine can be cooled by oil, and the rotation of the second rotating electric machine can be made smooth.

[0019] The drive device according to the first aspect of the present disclosure may further include a housing that houses the first rotating electric machine and the second rotating electric machine. Among them, in another embodiment, the drive device may include a first housing that houses the first rotating electric machine and a second housing that houses the second rotating electric machine.

[0020] The drive device according to the first aspect of the present disclosure may further include a first cooler that abuts at least a part of the surface of the first stator of the first rotating electric machine. The second refrigerant path may also be configured to cool the first rotating electric machine via the first cooler. Here, the "cooler" is, for example, a device including a flow path through which a refrigerant circulates, and is a so-called water tank.

[0021] According to such a configuration, the first rotating electric machine can be efficiently cooled by the first cooler.

[0022] The drive device according to the first aspect of the present disclosure may further include a second cooler that abuts at least a part of the surface of the second stator of the second rotating electric machine. The first refrigerant path may also be configured to cool the second rotating electric machine via the second cooler.

[0023] According to such a configuration, the second rotating electric machine can be efficiently cooled by the second cooler.

[0024] The drive device according to the first aspect of the present disclosure may further include: a first oil cooler configured to cool the first rotating electric machine; and a first oil pump configured to supply oil to the first rotating electric machine via the first oil cooler. The second refrigerant path may also be configured to cool the oil in the first oil cooler. And, in the second refrigerant path, the first cooler and the first oil cooler may be connected in series with each other.

[0025] According to such a configuration, the first rotating electric machine can be quickly cooled by oil and the first cooler.

[0026] The drive device according to the first aspect of the present disclosure may further include: a second oil cooler configured to cool the second rotating electric machine; and a second oil pump configured to supply oil to the second rotating electric machine via the second oil cooler. The first refrigerant path may also be configured to cool the oil in the second oil cooler. Further, in the first refrigerant path, the second cooler and the second oil cooler may be connected in series with each other.

[0027] According to such a configuration, the second rotating electric machine can be rapidly cooled by the oil and the second cooler.

[0028] It may also be configured that, based on the drive device according to the first aspect of the present disclosure, the drive device is configured to be mounted on a vehicle. The drive device may also constitute a charging circuit configured to supply a charging current supplied from an external power source of the vehicle to a power storage device of the vehicle via the neutral point of the first rotating electric machine.

[0029] In the above drive device, when supplying a charging current to the power storage device of the vehicle via the neutral point of the first rotating electric machine, only the first rotating electric machine and the first power device operate. In this case, the first rotating electric machine and the first power device generate heat, and the second rotating electric machine and the second power device do not generate heat. Therefore, the first refrigerant path that cools the non-heating second power device can efficiently cool the heating first rotating electric machine.

[0030] The drive device according to the first aspect of the present disclosure may further include: a first oil cooler configured to cool the first rotating electric machine; a first oil pump configured to supply oil to the first rotating electric machine via the first oil cooler; and a control device configured to control the first oil pump. The second refrigerant path may also be configured to cool the oil in the first oil cooler. Further, the control device may drive the first oil pump during at least a part of a charging period in which the charging current is supplied to the power storage device of the vehicle via the neutral point of the first rotating electric machine.

[0031] According to such a configuration, during the charging period, the first oil pump can supply the oil cooled by the first refrigerant path, that is, the path that cools the non-heating second power device, to the heating first rotating electric machine.

[0032] The drive device according to the first aspect of the present disclosure may further include: a second oil cooler configured to cool the second rotating electric machine; and a second oil pump configured to supply oil to the second rotating electric machine via the second oil cooler. The first refrigerant path may also be configured to cool the oil in the second oil cooler. Further, the control device may stop driving the second oil pump during at least a part of the charging period.

[0033] According to such a structure, during charging, the oil cooled by the second refrigerant path, that is, the path for cooling the first power device that generates heat, is not supplied to the second rotating electric machine that does not generate heat. Thereby, it is possible to prevent unnecessary driving of the second oil pump.

[0034] Based on the drive device according to the first aspect of the present disclosure, the drive device may also be configured to be mounted on a vehicle. The first rotating electric machine may also be configured to transmit power to the first drive wheel of the pair of left and right drive wheels of the vehicle, and the second rotating electric machine may also be configured to transmit power to the second drive wheel of the pair of left and right drive wheels of the vehicle. Among them, in another embodiment, the first rotating electric machine and the second rotating electric machine may also drive both of the pair of left and right drive wheels of the vehicle. And it may also be configured that the first rotating electric machine transmits power to the drive wheel located on the front side of the vehicle, and the second rotating electric machine transmits power to the drive wheel located on the rear side of the vehicle.

[0035] (First Embodiment)

[0036] Figure 1 A block diagram showing an electric vehicle 10 equipped with the drive device 20 of the first embodiment as viewed from above. In this specification, sometimes only the front of the electric vehicle 10 (i.e., Figure 1 the upper side of the paper surface) is represented as "front", and sometimes only the opposite side is represented as "rear". And sometimes only the left side of the electric vehicle 10 (i.e., Figure 1 the left side of the paper surface) is represented as "left", and sometimes only the opposite side is represented as "right". In addition, sometimes only the upper side of the electric vehicle 10 (i.e., Figure 1 the front direction of the paper surface) is represented as "up", and sometimes only the opposite side is represented as "down".

[0037] The electric vehicle 10 includes a vehicle body 2, a battery pack 3, a pair of left and right front wheels 4R, 4L, a pair of left and right rear wheels 5R, 5L, a charging socket 6, a drive device 20, a radiator 60, a pair of left and right cooling fans 61R, 61L, a first refrigerant path 62R, a second refrigerant path 62L, a first radiator pump 64R, and a second radiator pump 64L. The electric vehicle 10 travels by driving the pair of left and right front wheels 4R, 4L using the drive device 20. In addition, the "electric vehicle" in this specification includes, for example, a rechargeable electric vehicle charged by an external power source, a fuel cell vehicle powered by a fuel cell, and a hybrid vehicle having an engine. Hereinafter, the description of "a pair of left and right" may sometimes be abbreviated as "a pair".

[0038] The drive device 20 includes a housing 21, a pair of electric motors 30R and 30L, a pair of power transmission mechanisms 50R and 50L, a pair of oil coolers 22R and 22L, a pair of inverters 40R and 40L, and a control device 80.

[0039] The pair of electric motors 30R and 30L are both rotary electric machines. The drive device 20 supplies the power of the battery pack 3 to the pair of electric motors 30R and 30L via the pair of inverters 40R and 40L, thereby driving the pair of front wheels 4R and 4L. That is, the pair of front wheels 4R and 4L are the drive wheels of the electric vehicle 10. In a modified example, the pair of rear wheels 5R and 5L may be the drive wheels of the electric vehicle 10, and the pair of front wheels 4R and 4L and the pair of rear wheels 5R and 5L may also be the drive wheels of the electric vehicle 10.

[0040] The housing 21 houses the pair of electric motors 30R and 30L and the pair of power transmission mechanisms 50R and 50L. For the sake of understanding, in Figure 1 the figure, the shape of the housing 21 is indicated by a dashed line, and the devices such as the pair of electric motors 30R and 30L housed in the housing 21 are indicated by solid lines. The pair of inverters 40R and 40L include a first inverter 40R located on the right side and a second inverter 40L located on the left side, and are arranged on the upper surface of the housing 21. The pair of power transmission mechanisms 50R and 50L include a first power transmission mechanism 50R located on the right side and a second power transmission mechanism 50L located on the left side. The pair of electric motors 30R and 30L include a first electric motor 30R located on the right side and a second electric motor 30L located on the left side. The first power transmission mechanism 50R transmits the power of the first electric motor 30R to the right drive shaft 14R connected to the right front wheel 4R. The first power transmission mechanism 50R has a plurality of gears, bearings, etc. The first power transmission mechanism 50R functions as a speed reducer that decelerates the rotation speed of the first electric motor 30R and rotates the right drive shaft 14R. Similarly, the second power transmission mechanism 50L transmits the power of the second electric motor 30L to the left drive shaft 14L connected to the left front wheel 4L. As Figure 1 shown, the right drive shaft 14R and the left drive shaft 14L are separated at the center in the left - right direction of the electric vehicle 10. Therefore, the pair of front wheels 4R and 4L are independently driven by the pair of electric motors 30R and 30L. In a modified example, the drive shafts 14R and 14L may also be connected at the central portion. In this case, the two electric motors 30R and 30L may also drive the pair of front wheels 4R and 4L.

[0041] The charging socket 6 is arranged on the right side surface of the vehicle body 2. The charging socket 6 is configured to be connected to an external power source 7 (for example, a charging station) via a cable 8. When the charging socket 6 is connected to the external power source 7, the charging power of the external power source 7 is supplied to the battery pack 3.

[0042] A pair of oil coolers 22R and 22L are arranged on the front surface of the housing 21. The pair of oil coolers 22R and 22L includes a first oil cooler 22R on the right side and a second oil cooler 22L on the left side.

[0043] The radiator 60 is arranged at the front end of the body of the electric vehicle 10. The radiator 60 is a device for performing heat exchange between the refrigerant circulating in each refrigerant path 62R and refrigerant path 62L and the external air. The refrigerant is, for example, a liquid such as antifreeze or water. The radiator 60 cools the refrigerant by means of the wind generated by the cooling fans 61R and 61L, for example. The first radiator pump 64R circulates the refrigerant in the first refrigerant path 62R. The first refrigerant path 62R includes a first upstream path 66R, a first middle path 67R, and a first downstream path 68L. Similarly, the second radiator pump 64L circulates the refrigerant in the second refrigerant path 62L. The second refrigerant path 62L includes a second upstream path 66L, a second middle path 67L, and a second downstream path 68R. Each refrigerant path 62R and 62L merges at the merging path 69. That is, in the present embodiment, the same refrigerant flows in the first refrigerant path 62R and the second refrigerant path 62L. The merging path 69 connects the radiator 60 to each downstream path 68R and 68L.

[0044] As Figure 1 shown by the dashed arrow in, the first radiator pump 64R pumps the refrigerant into the first upstream path 66R. Thereby, the refrigerant reaches the first inverter 40R. And the refrigerant is supplied to the second oil cooler 22L via the first middle path 67R. The refrigerant that has passed through the second oil cooler 22L returns to the radiator 60 via the first downstream path 68L and the merging path 69. Similarly, in the second refrigerant path 62L, the refrigerant pumped into the second upstream path 66L by the second radiator pump 64L also flows in the order of the second inverter 40L, the second middle path 67L, the first oil cooler 22R, the second downstream path 68R, the merging path 69, and the radiator 60.

[0045] Refer to Figure 2, the electrical circuit of the drive device 20 will be described. In addition to a pair of electric motors 30R and 30L and a pair of inverters 40R and 40L, the drive device 20 also includes a power supply circuit 11. The power supply circuit 11 is a circuit for supplying the DC charging power supplied from the external power source 7 to the battery pack 3. The first electric motor 30R is a three-phase motor having a U-phase winding 35U, a V-phase winding 35V, and a W-phase winding 35W. The first inverter 40R includes a U-phase arm 42U, a V-phase arm 42V, and a W-phase arm 42W. Each phase arm 42U, 42V, and 42W has two switching elements connected in series. The first inverter 40R is a power conversion device that converts the DC power supplied from the battery pack 3 into three-phase alternating current power suitable for driving the first electric motor 30R by turning on and off the switching elements of each phase arm 42U, 42V, and 42W. One end of the U-phase winding 35U, V-phase winding 35V, and W-phase winding 35W of the first electric motor 30R is connected to each other at the neutral point NP. The other end of the U-phase winding 35U is connected to the midpoint of the two switching elements of the U-phase arm 42U, the other end of the V-phase winding 35V is connected to the midpoint of the two switching elements of the V-phase arm 42V, and the W-phase winding 35W is connected to the midpoint of the two switching elements of the W-phase arm 42W. In this way, the first inverter 40R is electrically connected to the first electric motor 30R.

[0046] Similarly, the second electric motor 30L also has a U-phase winding 35U, a V-phase winding 35V, and a W-phase winding 35W, and the second inverter 40L includes a U-phase arm 42U, a V-phase arm 42V, and a W-phase arm 42W. Each phase arm 42U, 42V, and 42W has two switching elements connected in series. The second inverter 40L is a power conversion device that converts the DC power supplied from the battery pack 3 into three-phase alternating current power suitable for driving the second electric motor 30L by turning on and off the switching elements of each phase arm 42U, 42V, and 42W. One end of the U-phase winding 35U, V-phase winding 35V, and W-phase winding 35W is connected to each other at the neutral point NP, the other end of the U-phase winding 35U is connected to the midpoint of the two switching elements of the U-phase arm 42U, the other end of the V-phase winding 35V is connected to the midpoint of the two switching elements of the V-phase arm 42V, and the W-phase winding 35W is connected to the midpoint of the two switching elements of the W-phase arm 42W. In this way, the second inverter 40L is electrically connected to the second electric motor 30L.

[0047] In the power supply circuit 11 of the present embodiment, one terminal of the charging socket 6 is connected to the positive electrode of the battery pack 3 via the neutral point NP of the first electric motor 30R and the first inverter 40R. The power supply circuit 11 supplies the charging power supplied from the external power source 7 to the neutral point NP of the first electric motor 30R. In addition, the other end portion of the charging socket 6 is connected to the negative electrode of the battery pack 3 via the first inverter 40R. The power supply circuit 11 supplies the charging power to the battery pack 3 via the neutral point NP of the first electric motor 30R. Thus, the first electric motor 30R and the first inverter 40R can function as three boost circuits connected in parallel between the charging socket 6 and the battery pack 3. Thus, the drive device 20 can boost the output voltage of the external power source 7 by using the first electric motor 30R and the first inverter 40R. Thus, even when the output voltage of the external power source 7 is lower than the voltage of the battery pack 3, rapid charging can be performed. In addition, one terminal of the charging socket 6 is directly connected to the positive electrode of the battery pack 3 via the switch 13. When the output voltage of the external power source 7 is the same as the voltage of the battery pack 3, the power supply circuit 11 can bypass the output voltage of the external power source 7 from the neutral point NP of the first electric motor 30R by turning on the switch 13. In addition, although not shown, the power supply circuit 11 further includes a charging unit including a relay, a capacitor, etc. The charging unit is connected to the neutral point NP and the first inverter 40R.

[0048] If the charging socket 6 is connected to the external power source 7 and the switch 13 is turned off, the charging power of the external power source 7 is supplied to the neutral point NP of the first electric motor 30R. Hereinafter, the period during which the charging power is supplied to the battery pack 3 via the supply to the neutral point NP of the first electric motor 30R may sometimes be referred to as the "charging period". Throughout the charging period, current flows through the windings 35U, 35V, 35W of each phase of the first electric motor 30R. Thus, the windings 35U, 35V, 35W of each phase generate heat, and the temperature of the first electric motor 30R rises. In addition, during the charging period, the switching elements of the phase arms 42U, 42V, 42W of the first inverter 40R electrically connected to the first electric motor 30R are turned on and off, whereby the temperature of the first inverter 40R rises. On the other hand, even if the charging socket 6 is connected to the external power source 7, current does not flow through the windings 35U, 35V, 35W of each phase of the second electric motor 30L, so the temperature of the second electric motor 30L does not rise. Therefore, the temperature of the second inverter 40L electrically connected to the second electric motor 30L also does not rise.

[0049] Refer to Figure 3 , and the detailed structure of the drive device 20 will be described. Figure 3 It is along Figure 1Cross-sectional view of the drive device of line III-III. In addition to the pair of electric motors 30R and 30L described above, the drive device 20 further includes a pair of oil pumps 70R and 70L housed in the housing 21, a pair of suction pipes 72R and 72L, and a pair of discharge pipes 74R and 74L. In addition, the housing 21 has a partition wall 26 extending downward at the center in the left-right direction. The partition wall 26 is a wall that separates the right space and the left space of the housing 21. However, the partition wall 26 does not reach the bottom surface of the housing 21. The right space and the left space of the housing 21 communicate with each other at the lower part of the housing 21. The first electric motor 30R and the first power transmission mechanism 50R are arranged to the right of the partition wall 26. The second electric motor 30L and the second power transmission mechanism 50L are arranged to the left of the partition wall 26. The drive device 20 is configured to be symmetric about the center of the partition wall 26, that is, the center line CL1. Therefore, hereinafter, the structure located to the right of the center line CL1 of the drive device 20 will be mainly described.

[0050] The first electric motor 30R includes a motor shaft 33R, a rotor 34R, and a stator 35R. The motor shaft 33R passes through the rotor 34R and extends in the left-right direction, and is rotatably held by the housing 21 by a pair of bearings 39R. The motor shaft 33R extends leftward beyond the left end of the rotor 34R and is connected to the gear of the first power transmission mechanism 50R. If the motor shaft 33R rotates when the rotor 34R rotates, the gear of the first power transmission mechanism 50R rotates. Although not shown in the figure, the first power transmission mechanism 50R rotates the right drive shaft 14R (refer to Figure 1 ). That is, the first power transmission mechanism 50R transmits the power of the first electric motor 30R to the right drive shaft 14R. The motor shaft 33R has a hollow structure. A plurality of through holes 38R are formed on the side surface of the motor shaft 33R. The plurality of through holes 38R communicate the internal space of the motor shaft 33R with the internal space of the housing 21. In addition, in Figure 1 , only two through holes 38R located at the right end among the plurality of through holes 38R are labeled with reference numerals, and the reference numerals of the other through holes 38R are omitted.

[0051] Similarly, the second electric motor 30L includes a motor shaft 33L, a rotor 34L, and a stator 35L. The motor shaft 33L passes through the rotor 34L and extends in the left-right direction, and is rotatably held by the housing 21 by a pair of bearings 39L. And the second power transmission mechanism 50L also transmits the power of the second electric motor 30L to the left drive shaft 14L via a gear or the like connected to the motor shaft 33L of the second electric motor 30L.

[0052] As Figure 3As shown, oil 76 accumulates in the lower part of the outer shell 21. The outer shell 21 forms a so-called oil accumulation part. A pair of oil pumps 70R and 70L includes a first oil pump 70R located on the right and a second oil pump 70L located on the left. The first oil pump 70R is fixed to the partition wall 26 from the right. The first oil pump 70R is a pump that supplies oil 76 to the first electric motor 30R. A pair of suction pipes 72R and 72L includes a first suction pipe 72R located on the right and a second suction pipe 72L located on the left. The first suction pipe 72R extends upward from the oil accumulation part and bends to the left, and is connected to the suction port of the first oil pump 70R. A pair of discharge pipes 74R and 74L includes a first discharge pipe 74R located on the right and a second discharge pipe 74L located on the left. The first discharge pipe 74R extends upward from the discharge port of the first oil pump 70R. The first discharge pipe 74R bends forward (i.e., Figure 3 inside the paper surface of the figure) and penetrates the front side wall of the outer shell 21, extends upward along the outer surface of the front side wall, and passes through the first oil cooler 22R disposed on the front side wall. And, after passing through the first oil cooler 22R, the first discharge pipe 74R penetrates the front side wall of the outer shell 21 again and enters the outer shell 21, and is connected to the left end of the motor shaft 33R of the first electric motor 30R. The first oil pump 70R supplies oil 76 to the motor shaft 33R of the first electric motor 30R via the first suction pipe 72R and the first discharge pipe 74R. The oil 76 supplied to the motor shaft 33R moves from the internal space of the motor shaft 33R to the internal space of the outer shell 21 through a plurality of through holes 38R. The oil 76 falls in the internal space of the outer shell 21 and accumulates again in the lower part of the outer shell 21. Thus, the first oil pump 70R circulates the oil 76. The oil 76 cools the first electric motor 30R and makes the rotation of the first electric motor 30R smooth. And, the oil 76 also lubricates the gears of the first power transmission mechanism 50R. Thereby, the first power transmission mechanism 50R rotates smoothly. In Figures 3 to 6 , the solid line arrow indicates the flow of the oil 76, and the dotted line arrow indicates the flow of the refrigerant.

[0053] Similarly, the second oil pump 70L is fixed to the partition wall 26 from the left. The second oil pump 70L is a pump that supplies oil 76 to the second electric motor 30L via the second suction pipe 72L and the second discharge pipe 74L. The second discharge pipe 74L is connected to the right end of the motor shaft 33L of the second electric motor 30L through the second oil cooler 22L. Thereby, oil 76 is supplied to the second electric motor 30L. As Figure 3 shown by the solid line arrow, the second oil pump 70L circulates the oil 76. The oil 76 cools the second electric motor 30L and makes the rotation of the second electric motor 30L and the second power transmission mechanism 50L smooth. Thus, in this embodiment, the first electric motor 30R and the second electric motor 30L are cooled by an oil-cooling system.

[0054] The control device 80 is disposed above the first inverter 40R. The control device 80 has a CPU and a memory, and is a computer that controls a pair of cooling fans 61R, 61L, a pair of radiator pumps 64R, 64L, and a pair of oil pumps 70R, 70L. The control device 80 controls each of the cooling fans 61R, 61L and each of the pumps 64R, 64L, 70R, 70L based on an instruction from a vehicle control unit (not shown) at a higher level. In addition, in a modified example, the control device 80 may be disposed on any one of the right side, left side, front side, and rear side of the first inverter 40R. Also, the control device 80 is not limited to one, and for example, it may be disposed on the left and right sides of the first inverter 40R.

[0055] As described above, the first discharge pipe 74R passes through the first oil cooler 22R and is connected to the motor shaft 33R of the first electric motor 30R. And, as referred to Figure 1 As described, the refrigerant cooled by the radiator 60 circulates to the first oil cooler 22R via the second refrigerant path 62L. Therefore, the refrigerant in the first oil cooler 22R cools the oil 76 in the first discharge pipe 74R. The oil 76 absorbs heat from the first electric motor 30R. That is, the second refrigerant path 62L cools the first electric motor 30R among the pair of electric motors 30R, 30L via the oil 76.

[0056] Similarly, the second discharge pipe 74L passes through the second oil cooler 22L and is connected to the motor shaft 33L of the second electric motor 30L. And, as referred to Figure 1 As described, the refrigerant cooled by the radiator 60 circulates to the second oil cooler 22L via the first refrigerant path 62R. Therefore, the refrigerant in the second oil cooler 22L cools the oil 76 in the second discharge pipe 74L. The oil 76 absorbs heat from the second electric motor 30L. That is, the first refrigerant path 62R cools the second electric motor 30L among the pair of electric motors 30R, 30L via the oil 76.

[0057] And, the first inverter 40R includes a first inverter cooler 41R. One end of the first inverter cooler 41R is connected to the first upstream path 66R of the first refrigerant path 62R, and the other end of the first inverter cooler 41R is connected to the first middle path 67R. The first middle path 67R is connected to the first downstream path 68L via the second oil cooler 22L (refer to Figure 1 ). The first inverter cooler 41R has a flow path for circulating the refrigerant, and cools the first inverter 40R by circulating the refrigerant. That is, the first refrigerant path 62R cools the first inverter 40R among the pair of inverters 40R, 40L via the refrigerant.

[0058] Similarly, the second inverter 40L is provided with a second inverter cooler 41L. One end of the second inverter cooler 41L is connected to the second upstream path 66L of the second refrigerant path 62L, and the other end of the second inverter cooler 41L is connected to the second middle flow path 67L. The second middle flow path 67L is connected to the second downstream path 68R via the first oil cooler 22R (see Figure 1 ). The second inverter cooler 41L has a flow path for circulating the refrigerant, and cools the second inverter 40L by circulating the refrigerant. That is, the second refrigerant path 62L cools the second inverter 40L among the pair of inverters 40R and 40L via the refrigerant.

[0059] As Figure 3 shown, the first middle flow path 67R of the first refrigerant path 62R connects the first inverter cooler 41R of the first inverter 40R located on the right side of the center line CL1 and the second oil cooler 22L located on the left side of the center line CL1. In addition, the second middle flow path 67L of the second refrigerant path 62L connects the second inverter cooler 41L of the second inverter 40L located on the left side of the center line CL1 and the first oil cooler 22R located on the right side of the center line CL1. Therefore, the first middle flow path 67R extends from the right side of the center line CL1 across the center line CL1 to the left side, and the second middle flow path 67L extends from the left side of the center line CL1 across the center line CL1 to the right side. As a result, when viewed from the rear of the vehicle, the middle flow paths 67R and 67L cross each other.

[0060] As described above, the first electric motor 30R is electrically connected to the first inverter 40R. And the first electric motor 30R is cooled by the same second refrigerant path 62L as the second inverter 40L. That is, the first electric motor 30R is electrically connected to the first inverter 40R, and the first inverter 40R is different from the second inverter 40L cooled by the same refrigerant path 62L as itself.

[0061] Similarly, the second electric motor 30L is electrically connected to the second inverter 40L. And the second electric motor 30L is cooled by the same first refrigerant path 62R as the first inverter 40R. That is, the second electric motor 30L is electrically connected to the second inverter 40L, and the second inverter 40L is different from the first inverter 40R cooled by the same refrigerant path 62R as itself.

[0062] (Effects of this embodiment)

[0063] The control device 80 drives a pair of cooling fans 61R and 61L, the second radiator pump 64L, and the first oil pump 70R when the charging socket 6 is connected to an external power source 7 via a cable 8 and the switch 13 is turned off. Thereby, during charging, the refrigerant cooled by the pair of cooling fans 61R and 61L is supplied to the first oil cooler 22R via the second refrigerant path 62L. And, the oil 76 cooled by the refrigerant in the first oil cooler 22R is supplied to the first electric motor 30R. The second refrigerant path 62L supplies the refrigerant to the first oil cooler 22R via the second inverter cooler 41L of the second inverter 40L. The refrigerant that has passed through the non-heated second inverter 40L is supplied to the first oil cooler 22R, and the oil 76 cooled by this refrigerant cools the first electric motor 30R that is driven during charging. That is, in the drive device 20 of the present embodiment, the electrically connected first electric motor 30R and the first inverter 40R are not cooled by the same second refrigerant path 62L. Thereby, for each of the refrigerant paths 62R and 62L, it is possible to equalize the required cooling amount, and thus it is possible to improve the cooling efficiency in the drive device 20.

[0064] In addition, the control device 80 drives the first radiator pump 64R during charging and stops the drive of the second oil pump 70L. Thereby, the first inverter 40R that operates during charging can be cooled by the refrigerant circulating in the first refrigerant path 62R. In addition, during charging, the oil 76 is not supplied to the second electric motor 30L. As described above, the second electric motor 30L does not drive during charging, so the temperature of the second electric motor 30L does not rise. Thus, in the drive device 20 of the present embodiment, by stopping the drive of the second oil pump 70L during charging, it is possible to prevent the second oil pump 70L from being driven unnecessarily to supply the oil 76 to the non-driven second electric motor 30L.

[0065] (Second Embodiment)

[0066] Refer to Figure 4 , and the drive device 120 of the second embodiment will be described. The drive device 120 of the present embodiment further includes a pair of coolers 120R and 120L on the basis of the structure of the drive device 20 of the first embodiment described above. The pair of coolers 120R and 120L includes a first cooler 120R that cools the first electric motor 30R and a second cooler 120L that cools the second electric motor 30L. That is, in the present embodiment, the first electric motor 30R and the second electric motor 30L are cooled by an oil-water cooling system that combines oil cooling and water cooling. The first cooler 120R abuts against the outer surface of the stator 35R of the first electric motor 30R. The first cooler 120R cools the stator 35R by passing the refrigerant through. The first cooler 120R is connected to the second refrigerant path 62L (refer toFigure 1 ) The second connecting pipe 167R of () is connected to the first oil cooler 122R. The refrigerant that has passed through the first cooler 120R passes through the second downstream path 168R and the confluence path 69 (see Figure 1 ) and returns to the radiator 60.

[0067] Similarly, the second cooler 120L abuts against the outer surface of the stator 35L of the second electric motor 30L. The second cooler 120L is connected to the second oil cooler 122L via the first connecting pipe 167L of the first refrigerant path 62R (see Figure 1 ) The refrigerant that has passed through the second cooler 120L passes through the first downstream path 168L and the confluence path 69 (see Figure 1 ) and returns to the radiator 60.

[0068] In the drive device 120 of the present embodiment, in addition to the oil 76, the first electric motor 30R is cooled by the refrigerant. Thus, the first electric motor 30R can be quickly cooled by the oil 76 and the refrigerant.

[0069] (Third Embodiment)

[0070] Refer to Figure 5 , the drive device 220 of the third embodiment will be described. When compared with the drive device 120 of the above-described second embodiment, the drive device 220 of the present embodiment does not include a pair of oil coolers 22R, 22L and a pair of oil pumps 70R, 70L. That is, in the present embodiment, the first electric motor 30R and the second electric motor 30L are cooled by a water-cooled cooling system. Therefore, in the drive device 220 of the present embodiment, the first inverter cooler 41R of the first inverter 40R is directly connected to the second cooler 120L via the first middle flow path 267R, and the second inverter cooler 41L of the second inverter 40L is directly connected to the first cooler 120R via the second middle flow path 267L. Similar to the second embodiment, the refrigerant that has passed through the first cooler 120R passes through the first downstream path 268R and the confluence path 69 (see Figure 1 ) and returns to the radiator 60, and the refrigerant that has passed through the second cooler 120L passes through the second downstream path 268L and the confluence path 69 (see Figure 1 ) and returns to the radiator 60.

[0071] And, in the drive device 220 of the present embodiment, the oil 76 (see Figure 3 ) does not accumulate in the lower part of the housing. Therefore, in the drive device 220, there is provided a first housing 221R that houses the first electric motor 30R and a second housing 221L that houses the second electric motor 30L. The respective housings 221R, 221L are arranged in the left-right direction.

[0072] (Embodiment 4)

[0073] Refer to Figure 6 , and the drive device 320 of the fourth embodiment will be described. The drive device 320 of this embodiment has substantially the same structure as the drive device 20 of the first embodiment, but the arrangement positions of the respective devices are different. In this embodiment, the electric motors 330R and 330L are arranged at the center in the left-right direction of the housing 321. The motor shaft 333R of the first electric motor 330R extends to the right beyond the right end of the rotor 34R. The motor shaft 333R is connected to the first power transmission mechanism 350R located to the right of the first electric motor 330R. Similarly, the motor shaft 333L of the second electric motor 330L extends to the left beyond the left end of the rotor 34L. The motor shaft 333L is connected to the second power transmission mechanism 350L located to the left of the second electric motor 330L.

[0074] The first oil pump 370R is arranged on the inner wall on the right side of the housing 321, and the second oil pump 370L is arranged on the inner wall on the left side of the housing 321. In addition, the first oil cooler 322R is arranged on the outer wall on the right side of the housing 321, and the second oil cooler 322L is arranged on the outer wall on the left side of the housing 321. The first oil cooler 322R houses a part of the first discharge pipe 374R that extends upward along the outer wall on the right side of the housing 321. The first oil pump 370R sucks up the oil 76 through the first suction pipe 372R, and supplies the oil 76 to the motor shaft 333R of the first electric motor 330R via the first discharge pipe 374R. Thus, the oil 76 cooled by the refrigerant in the first oil cooler 322R is supplied to the first electric motor 330R. Similarly, the second oil cooler 322L houses a part of the second discharge pipe 374L that extends upward along the outer wall on the left side of the housing 321. The second oil pump 370L sucks up the oil 76 through the second suction pipe 372L, and supplies the oil 76 to the motor shaft 333L of the second electric motor 30L via the second discharge pipe 374L. Thus, the oil 76 cooled by the refrigerant in the second oil cooler 322L is supplied to the second electric motor 330L.

[0075] As Figure 6 shown, in this embodiment, the first inverter cooler 41R of the first inverter 40R located to the right of the center line CL1 is also connected to the second oil cooler 322L located to the left through the first middle flow path 367R. And the second inverter cooler 41L of the second inverter 40L located to the left of the center line CL1 is connected to the first oil cooler 322R located to the right through the second middle flow path 367L. Therefore, when viewed from the rear of the vehicle, the respective middle flow paths 367R and 367L cross each other.

[0076] As described above, specific examples of the technology disclosed in this specification have been described in detail, but these are merely examples and do not limit the claims. The technology described in the claims includes technologies obtained by various modifications and changes to the specific examples illustrated above. Hereinafter, modification examples of the above-described embodiments will be listed.

[0077] (Modification Example 1) In the above-described embodiment, the drive device 20 includes two electric motors 30R and 30L, two inverters 40R and 40L, and two refrigerant paths 62R and 62L. However, the number of electric motors, inverters, and refrigerant paths is not limited to two. For example, the drive device 20 may also include three electric motors, three inverters, and three refrigerant paths. In this case, it may be configured such that the first electric motor is electrically connected to the first inverter, the second electric motor is electrically connected to the second inverter, and the third electric motor is electrically connected to the third inverter. And it may also be configured such that the first refrigerant path cools the first inverter and the second electric motor, the second refrigerant path cools the second inverter and the third electric motor, and the third refrigerant path cools the third inverter and the first electric motor. Further, in another modification example, the drive device 20 may also include two electric motors for driving a pair of front wheels 4R and 4L, two electric motors for driving a pair of rear wheels 5R and 5L, and four inverters electrically connected to the respective motors. In still another modification example, it may be configured such that the first electric motor drives a pair of front wheels 4R and 4L, and the second electric motor drives a pair of rear wheels 5R and 5L. In this case, the first electric motor and the second electric motor may be arranged in the left-right direction or in the front-rear direction.

[0078] (Modification Example 2) The drive device 20 of the first embodiment may not include the power supply circuit 11. In this modification example, the drive device 20 may supply charging power to the battery pack 3 without passing through the neutral point NP of the first electric motor 30R. In this modification example, for example, when the rotational speed of the first electric motor 30R exceeds a specified value, the control device 80 may drive a pair of cooling fans 61R and 61L, the second radiator pump 64L, and the first oil pump 70R. For example, when the electric vehicle 10 is traveling on a road that bends to the left, the rotational speed of the first electric motor 30R that drives the right front wheel 4R sometimes exceeds the specified value. In this modification example, it is possible to efficiently cool one electric motor with a larger rotational speed by using the refrigerant that cools the inverter electrically connected to the other electric motor with a smaller rotational speed.

[0079] (Modification Example 3) The drive device 20 of the first embodiment includes two oil pumps 70R and 70L, but in this modification example, it may include one oil pump. In this modification example, oil 76 may be supplied to the two electric motors 30R and 30L by one oil pump. In this modification example, this one oil pump is an example of the "first oil pump" and the "second oil pump".

[0080] (Modification Example 4) The control device 80 may also not stop the second oil pump 70L during charging. In this modification example, the control device 80 may also drive the pair of cooling fans 61R, 61L, the pair of radiator pumps 64R, 64L, and the pair of oil pumps 70R, 70L throughout the charging period. Additionally, in another modification example, when the temperature of the first electric motor 30R exceeds a specified temperature during charging, the control device 80 may also drive the pair of cooling fans 61R, 61L, the second radiator pump 64L, and the first oil pump 70R.

[0081] The technical elements described in this specification or the drawings exhibit technical usefulness either individually or through various combinations, and are not limited to the combinations recited in the claims at the time of application. Additionally, the technologies exemplified in this specification or the drawings can achieve multiple purposes simultaneously, and achieving one of these purposes itself has technical usefulness.

Claims

1. A driving device, characterized in that: The driving device comprises: Multiple rotating motors; a plurality of power conversion devices; and The plurality of refrigerant paths are configured to be arranged in parallel with each other and to cool the plurality of rotating electrical machines and the plurality of power conversion devices. The plurality of power conversion devices are respectively electrically connected to at least one of the plurality of rotating electrical machines. The plurality of refrigerant paths are respectively configured to cool at least one of the plurality of power conversion devices and at least one of the plurality of rotating electrical machines. The plurality of rotating electrical machines are respectively electrically connected to a power conversion device different from the at least one power conversion device cooled by the same refrigerant path as the plurality of rotating electrical machines.

2. The driving device according to claim 1, characterized in that: The plurality of rotating electrical machines include a first rotating electrical machine and a second rotating electrical machine, The plurality of power conversion devices include: a first power conversion device electrically connected to the first rotating electrical machine; and a second power conversion device electrically connected to the second rotating electrical machine; The plurality of refrigerant paths include: a first refrigerant path configured to cool the first power conversion device and the second rotating electrical machine; and The second coolant path is configured to cool the second power conversion device and the first rotating electrical machine.

3. The driving device according to claim 2, characterized in that: Also available: a first oil cooler configured to cool the first rotating electrical machine; and The first oil pump is configured to supply oil to the first rotating electrical machine via the first oil cooler, wherein the second refrigerant path is configured to cool the oil in the first oil cooler.

4. The driving device according to claim 3, characterized in that: Also available: a second oil cooler configured to cool the second rotating electrical machine; and The second oil pump is configured to supply oil to the second rotating electrical machine via the second oil cooler, wherein the first refrigerant path is configured to cool the oil in the second oil cooler.

5. The driving device according to claim 2, characterized in that: A housing for accommodating the first rotating electrical machine and the second rotating electrical machine is further provided.

6. The driving device according to claim 2, characterized in that: further comprising a first cooler abutting against at least a portion of a surface of a first stator of the first rotating electrical machine, Here, the second refrigerant path is configured to cool the first rotating electrical machine via the first cooler.

7. The driving device according to claim 6, characterized in that: further comprising a second cooler abutting against at least a portion of a surface of a second stator of the second rotating electrical machine, Here, the first refrigerant path is configured to cool the second rotating electrical machine via the second cooler.

8. The driving device according to claim 6, characterized in that: Also available: a first oil cooler configured to cool the first rotating electrical machine; and The first oil pump is configured to supply oil to the first rotating electrical machine via the first oil cooler, and the second refrigerant path is further configured to cool the oil in the first oil cooler. In the second refrigerant path, the first cooler and the first oil cooler are connected in series with each other.

9. The driving device according to claim 7, characterized in that: Also available: a second oil cooler configured to cool the second rotating electrical machine; and a second oil pump configured to supply oil to the second rotating electrical machine via the second oil cooler, The first refrigerant path is further configured to cool the oil in the second oil cooler. In the first refrigerant path, the second cooler and the second oil cooler are connected in series with each other.

10. The driving device according to claim 2, characterized in that: The driving device is configured to be mounted on a vehicle. The drive device constitutes a charging circuit that supplies a charging current supplied from a power source external to the vehicle to the power storage device of the vehicle via a neutral point of the first rotating electrical machine.

11. The driving device according to claim 10, characterized in that: Also available: a first oil cooler configured to cool the first rotating electrical machine; a first oil pump configured to supply oil to the first rotating electrical machine via the first oil cooler; and a control device configured to control the first oil pump, The second refrigerant path is configured to cool the oil in the first oil cooler. The control device drives the first oil pump during at least a portion of a charging period in which the charging current is supplied to the power storage device of the vehicle via a neutral point of the first rotating electric machine.

12. The driving device according to claim 11, characterized in that: Also available: a second oil cooler configured to cool the second rotating electrical machine; and a second oil pump configured to supply oil to the second rotating electrical machine via the second oil cooler, The first refrigerant path is configured to cool the oil in the second oil cooler. The control device stops driving of the second oil pump during at least a portion of the charging period.

13. The driving device according to claim 2, characterized in that: The drive device is configured to be mounted on a vehicle; The first rotating electric machine is configured to transmit power to a first driving wheel of a pair of left and right driving wheels of the vehicle; The second rotating electric machine is configured to transmit power to a second drive wheel of a pair of left and right drive wheels of the vehicle.

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