Driving device

Abstract

To provide a technique suppressing extreme shift of the gravity center of a driving device to the side of a charging unit.SOLUTION: A driving device includes: a first drive unit having a first electric motor and driving one of a pair of right and left wheels; a second drive unit having a second electric motor and driving the other of the pair of right and left wheels; a casing; a first power conversion unit electrically connected to the first electric motor; a charging unit energizing electric current to the first power conversion unit via a neutral point of the first electric motor; and one or more functional components providing a prescribed function to at least one of the first driving unit and the second driving unit. The first drive unit and the second drive unit are distributed to both sides of a reference surface of the casing perpendicular to a longitudinal direction of the vehicle. The gravity center of the charging unit locates on one side of the reference surface in the longitudinal direction of the vehicle, and the gravity center of the whole of one or more functional components locates on the other side of the reference surface in the longitudinal direction of the vehicle.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a drive device including a speed reducer housed in a casing in a left-right parallel arrangement, and electric motors disposed on both the left and right sides of the speed reducer. Patent Document 2 discloses a technology that uses two electric motors for driving drive wheels to charge a power storage device. In the technology of Patent Document 2, power from a charging device outside the vehicle is supplied to the power storage device via the neutral point of one of the two electric motors.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the drive device of Patent Document 1, the two speed reducers are distributed on both sides of the reference plane of the casing perpendicular to the left - right direction. Similarly, the two electric motors are distributed on both sides of the reference plane of the casing. As a result, the center of gravity of the drive device approaches the reference plane of the casing, improving the stability of the drive device during driving. In a configuration such as that of Patent Document 2, where the power of a charging device outside the vehicle is supplied to the power storage device via the neutral point of one of the two electric motors, the charging unit electrically connected to the neutral point of the one electric motor may be arranged on one side of the reference plane of the casing. In this case, the center of gravity of the drive device may move significantly toward the charging unit side from the reference plane. As a result, the stability of the drive device during driving may be reduced. In this specification, a technique is provided that can suppress the significant movement of the center of gravity of a drive device equipped with a charging unit toward the charging unit side.

Means for Solving the Problems

[0005] The technology disclosed in this specification is embodied by a drive device that drives a pair of left - and - right wheels mounted on a vehicle. The drive device includes a first drive unit having a first electric motor and driving one of the pair of left - and - right wheels, a second drive unit having a second electric motor and driving the other of the pair of left - and - right wheels, a casing housing the first drive unit and the second drive unit, a first power conversion unit electrically connected to the first electric motor, a charging unit electrically connected to the neutral point of the first electric motor and passing an electric current to the first power conversion unit through the neutral point, and one or more functional components providing a predetermined function to at least one of the first drive unit and the second drive unit. The first drive unit and the second drive unit are distributed on both sides of the reference plane of the casing perpendicular to the left - right direction of the vehicle, the center of gravity of the charging unit is located on one side of the reference plane in the left - right direction of the vehicle, and the overall center of gravity of the one or more functional components is located on the other side of the reference plane in the left - right direction of the vehicle.

[0006] In the drive device described above, the center of gravity of the charging unit is located on one side of the reference plane in the vehicle left-right direction, and the overall center of gravity of the one or more functional components is located on the other side of the reference plane in the vehicle left-right direction. Therefore, the difference in weight between both sides of the reference plane is reduced. As a result, it is possible to suppress the significant movement of the center of gravity of the drive device from the reference plane toward the charging unit side due to the weight of the charging unit.

[0007] Details and further improvements of the technology disclosed in this specification will be described in the following "Mode for Carrying Out the Invention".

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0009] In one embodiment of the present technology, the predetermined function may include a lock function for locking the drive of either one of the first drive unit and the second drive unit. In that case, the one or more functional components may include a lock component for mechanically locking the one drive unit and an actuator for operating the lock component.

[0010] With such a configuration, even if the charging unit is arranged on one side of the reference plane, it is possible to suppress the center of gravity of the drive device from moving to one side of the reference plane by utilizing the weights of the locking components and the actuator required for the vehicle.

[0011] In one embodiment of the present technology, the one drive unit may be a drive unit located on the other side of the reference plane in the vehicle left - right direction. In that case, the center of gravity of the locking component and the center of gravity of the actuator may both be located on the other side of the reference plane in the vehicle left - right direction.

[0012] With such a configuration, the centers of gravity of the locking component and the actuator for locking the drive of the drive unit located on the other side are arranged on the other side of the reference plane. For this reason, since the locking component and the actuator can be arranged near the corresponding drive unit, simplification of the configuration of the locking component and the actuator can be achieved.

[0013] In one embodiment of the present technology, the one drive unit may be a drive unit located on one side of the reference plane in the vehicle left - right direction. In that case, the center of gravity of the locking component is located on one side of the reference plane in the vehicle left - right direction, and the center of gravity of the actuator may be located on the other side of the reference plane in the vehicle left - right direction. Further, the actuator may have a weight larger than the weight of the locking component.

[0014] With such a configuration, it is possible to suppress the center of gravity of the drive device from moving to one side of the reference plane by utilizing the weight of the actuator, which is larger than the weight of the locking component.

[0015] In one embodiment of the present technology, the predetermined function may include a supply function of supplying a heat medium to at least one of the first drive unit and the second drive unit. In that case, it may include one or a plurality of supply units for supplying the heat medium to the at least one drive unit.

[0016] According to such a configuration, even if the charging unit is arranged on one side of the reference plane, it is possible to suppress the movement of the center of gravity of the drive device to one side of the reference plane by utilizing the weight of the supply unit for supplying the heat medium to at least one of the drive units.

[0017] In one embodiment of the present technology, the at least one drive unit may be a drive unit located on the other side of the reference plane in the vehicle left-right direction.

[0018] According to such a configuration, the center of gravity of the supply unit for supplying the heat medium to the drive unit located on the other side is arranged on the other side of the reference plane. Therefore, since the supply unit can be arranged near the corresponding drive unit, simplification of the configuration of the supply unit can be achieved.

[0019] In one embodiment of the present technology, the at least one drive unit may be the first drive unit and the second drive unit. In that case, the one or more supply units may include a first supply unit that provides the supply function to the first drive unit and a second supply unit that provides the supply function to the second drive unit. Further, the center of gravity of the first supply unit may be located on one side of the reference plane in the vehicle left-right direction, and the center of gravity of the second supply unit may be located on the other side of the reference plane in the vehicle left-right direction. In that case, the distance between the center of gravity of the first supply unit and the reference plane may be smaller than the distance between the center of gravity of the second supply unit and the reference plane.

[0020] According to such a configuration, the overall center of gravity of the first supply unit and the second supply unit will be located on the other side of the reference plane in the vehicle left-right direction. Thereby, it is possible to suppress the movement of the center of gravity of the drive device to one side of the reference plane.

[0021] In one embodiment of the present technology, the at least one drive unit may be the first drive unit and the second drive unit. In that case, the one or more supply units may include a first supply unit that provides the supply function to the first drive unit and a second supply unit that provides the supply function to the second drive unit. Further, the center of gravity of the first supply unit and the center of gravity of the second supply unit may both be located on the other side of the reference plane in the vehicle left-right direction.

[0022] According to such a configuration, in addition to the center of gravity of the second supply unit that supplies the heat medium to the second drive unit, the center of gravity of the first supply unit that supplies the heat medium to the first drive unit is also arranged on the other side of the reference plane. Therefore, by using the two supply units, it is possible to suppress the center of gravity of the drive device from moving to one side of the reference plane.

[0023] In one embodiment of the present technology, the first drive unit may be located on one side of the reference plane in the vehicle left-right direction. However, in another embodiment, the first drive unit may be located on the other side of the reference plane.

[0024] In one embodiment of the technology, the charging unit may include a capacitor. Since the capacitor has a relatively large weight, when the charging unit including the capacitor is arranged on one side of the reference plane, the center of gravity of the drive device tends to move to one side. Therefore, the present technology is particularly beneficial in the case of a configuration in which the charging unit includes a capacitor.

[0025] In one embodiment of the present technology, the drive device may further include a second power conversion unit electrically connected to the second electric motor. However, in another embodiment, the drive device may not include the second power conversion unit.

[0026] (First Embodiment) Figure 1 shows a block diagram of an electric vehicle 10 equipped with the drive device 20 of the present embodiment as viewed from above. Figure 2 shows a cross-sectional view of the drive device 20 taken along line II-II of Figure 1. In this specification, the front of the electric vehicle 10 (i.e., above the paper surface of Figure 1) may be simply referred to as "front", and the opposite side may be simply referred to as "rear". Further, the left side of the electric vehicle 10 (i.e., the left side of the paper surface of Figure 1) may be simply referred to as "left", and the opposite side may be simply referred to as "right".

[0027] As shown in Figure 1, the electric vehicle 10 includes a vehicle body 2, a battery pack 3, a pair of left and right front wheels 4R and 4L, a pair of left and right drive shafts 14R and 14L, a pair of left and right rear wheels 5R and 5L, a charging inlet 6, a parking brake 9, and a drive device 20. The electric vehicle 10 travels by driving a pair of left and right front wheels 4R and 4L by the drive device 20. In a modified example, the drive device 20 may drive a pair of left and right rear wheels 5R and 5L. Note that the "electric vehicle" in this specification includes, for example, a rechargeable electric vehicle charged by an external power source, a fuel cell vehicle using a fuel cell as a power source, and a hybrid vehicle having an engine. Hereinafter, the description "a pair of left and right" may be simply described as "a pair".

[0028] The charging inlet 6 is disposed on the right side surface of the vehicle body 2. The charging inlet 6 is configured to be connected to an external DC power source 7 (e.g., a charging stand) via a power cable 8.

[0029] As particularly shown in FIG. 2, the drive device 20 includes a casing 21, a first inverter 30R, a second inverter 30L, a charging unit 40, a first drive unit 50R, a second drive unit 50L, an actuator 60, a parking gear 62, a lock pole 63, a first supply unit 70R, and a second supply unit 70L. In the drive device 20, each of the inverters 30R, 30L, the charging unit 40, each of the drive units 50R, 50L, the actuator 60, the parking gear 62, the lock pole 63, each of the supply units 70R, 70L is housed or integrally fixed to the casing 21. The drive device 20 is an electromechanical integrated unit called so-called X-in-1. The casing 21 houses each of the drive units 50R, 50L together with the heat medium H1. The casing 21 includes a first unit chamber 22, a second unit chamber 24, and a partition wall 26. The first unit chamber 22 houses the first drive unit 50R, and the second unit chamber 24 houses the second drive unit 50L. The heat medium H1 stays at the lower parts of the first unit chamber 22 and the second unit chamber 24.

[0030] The partition wall 26 is interposed between the first unit chamber 22 and the second unit chamber 24. The partition wall 26 extends in the vertical direction at the central portion of the casing 21 in the left-right direction. That is, it extends in a direction perpendicular to the left-right direction. In the present embodiment, a plane extending along the center of the partition wall 26 in the left-right direction is defined as a reference plane BP of the casing 21.

[0031] Of the pair of drive shafts 14R, 14L, the right drive shaft 14R mechanically connects the drive device 20 to the right front wheel 4R, which is one of the pair of front wheels 4R, 4L. Of the pair of drive shafts 14R, 14L, the left drive shaft 14L mechanically connects the drive device 20 to the left front wheel 4L, which is the other of the pair of front wheels 4R, 4L.

[0032] The first drive unit 50R drives the right front wheel 4R via the right drive shaft 14R. The first drive unit 50R includes a first electric motor 52R and a first gear mechanism 57R. The second drive unit 50L drives the left front wheel 4L via the left drive shaft 14L. The second drive unit 50L includes a second electric motor 52L and a second gear mechanism 57L. The first drive unit 50R is located on one side (right side) of the reference plane BP of the partition wall 26, and the second drive unit 50L is located on the other side (left side) of the reference plane BP. That is, the first drive unit 50R and the second drive unit 50L are distributed on both sides of the reference plane BP. Note that the first drive unit 50R and the second drive unit 50L may be arranged symmetrically with respect to the reference plane BP. Thereby, since the mechanism for transmitting the power of the first drive unit 50R to the right front wheel 4R and the mechanism for transmitting the power of the second drive unit 50L to the left front wheel 4L can be arranged in a well-balanced manner on both sides of the reference plane BP, it is easy to improve the stability during the driving of the drive device 20.

[0033] The first electric motor 52R is a prime mover for driving the right front wheel 4R. The first electric motor 52R is mechanically connected to the right front wheel 4R via the first gear mechanism 57R and the right drive shaft 14R. The second electric motor 52L is a prime mover for driving the left front wheel 4L. The second electric motor 52L is mechanically connected to the left front wheel 4L via the second gear mechanism 57L and the left drive shaft 14L. That is, the drive device 20 of the present embodiment independently drives each of the front wheels 4R and 4L by two electric motors 52R and 52L.

[0034] The first gear mechanism 57R is interposed between the first electric motor 52R and the right drive shaft 14R. The first gear mechanism 57R includes a plurality of gears 58R, a plurality of rotating shafts 54R, and a plurality of bearings 56R. The plurality of gears 58R are engaged in series to transmit torque between the first electric motor 52R and the right front wheel 4R. Each rotating shaft 54R holds at least one gear 58R and is rotatably supported by the casing 21 by two or more bearings 56R. Although not particularly limited, the first gear mechanism 57R may be a speed reducer configured to amplify the torque output by the first electric motor 52R and transmit it to the right front wheel 4R.

[0035] The second gear mechanism 57L is interposed between the second electric motor 52L and the left drive shaft 14L. The second gear mechanism 57L includes a plurality of gears 58L, a plurality of rotating shafts 54L, and a plurality of bearings 56L. The plurality of gears 58L are engaged in series to transmit torque between the second electric motor 52L and the left front wheel 4L. Each rotating shaft 54L holds at least one gear 58L and is rotatably supported by the casing 21 by two or more bearings 56L. Although not particularly limited, the second gear mechanism 57L may be a speed reducer configured to amplify the torque output by the second electric motor 52L and transmit it to the left front wheel 4L.

[0036] The first supply unit 70R is located on the right side surface of the casing 21. The first supply unit 70R includes an upstream pipe 72R, a first oil pump 71R, a downstream pipe 74R, and a first oil cooler 76R. The first oil pump 71R sucks in the heat medium H1 staying in the lower part of the first unit chamber 22 of the casing 21 through the upstream pipe 72R and pumps it to the downstream pipe 74R. Thereby, the heat medium H1 passes through the first oil cooler 76R and is supplied to the first electric motor 52R of the first electric motor 52R. Further, after passing through the first electric motor 52R, the heat medium H1 passes through the surface of the first gear mechanism 57R and stays in the lower part of the first unit chamber 22 again.

[0037] The second supply unit 70L is located on the left side surface of the casing 21. That is, the second supply unit 70L is located on the left side of the reference plane BP. The second supply unit 70L includes an upstream pipe 72L, a second oil pump 71L, a downstream pipe 74L, and a second oil cooler 76L. The second oil pump 71L sucks the heat medium H1 staying in the lower part of the second unit chamber 24 of the casing 21 through the upstream pipe 72L and pumps it to the downstream pipe 74L. Thereby, the heat medium H1 passes through the second oil cooler 76L and is supplied to the second electric motor 52L. Further, after passing through the second electric motor 52L, the heat medium H1 passes through the surface of the second gear mechanism 57L and stays again in the lower part of the second unit chamber 24. In this way, each supply unit 70R, 70L circulates the heat medium H1 in the casing 21. The heat medium H1 may be, for example, oil that functions as a lubricant for each of the gear mechanisms 57R, 57L. Also, another heat medium cooled by a radiator (not shown) of the electric vehicle 10 circulates in each of the oil coolers 76R, 76L. For this reason, the heat medium H1 that has passed through each of the oil coolers 76R, 76L also functions as a refrigerant for cooling the electric motors 52R, 52L, for example.

[0038] On the upper surface of the casing 21, a first inverter 30R, a second inverter 30L, a charging unit 40, and an actuator 60 are arranged.

[0039] FIG. 3 shows a circuit diagram of the drive device 20. The first electric motor 52R is a three-phase motor including a U-phase coil 55U, a V-phase coil 55V, and a W-phase coil 55W. The second electric motor 52L has the same configuration as the first electric motor 52R. That is, the second electric motor 52L is also a three-phase motor including a U-phase coil 55U, a V-phase coil 55V, and a W-phase coil 55W.

[0040] The first inverter 30R is electrically connected between the first electric motor 52R and the traveling smoothing capacitor 34. The first inverter 30R includes a U-phase arm 32U, a V-phase arm 32V, and a W-phase arm 32W. Each of the phase arms 32U, 32V, and 32W is connected in parallel with each other. Each of the phase arms 32U, 32V, and 32W includes two switching elements connected in series. The second inverter 30L has the same configuration as the first inverter 30R. That is, the second inverter 30L also includes a U-phase arm 32U, a V-phase arm 32V, and a W-phase arm 32W.

[0041] One end of each of the U-phase coil 55U, the V-phase coil 55V, and the W-phase coil 55W of the first electric motor 52R is connected to the neutral point NP1. The other end of the U-phase coil 55U of the first electric motor 52R is connected to the U-phase arm 32U of the first inverter 30R via a current sensor. Similarly, the other end of the V-phase coil 55V of the first electric motor 52R is connected to the V-phase arm 32V of the first inverter 30R via a current sensor, and the other end of the W-phase coil 55W is connected to the W-phase arm 32W of the first inverter 30R via a current sensor. For each of the phase coils 55U, 55V, and 55W of the second electric motor 52L, they are similarly connected to the respective phase arms 32U, 32V, and 32W of the second inverter 30L.

[0042] The charging unit 40 is electrically connected between the charging inlet 6 and the first electric motor 52R. More specifically, the charging unit 40 electrically connects one terminal of the charging inlet 6 to the neutral point NP1 of the first electric motor 52R, and connects the other terminal of the charging inlet 6 to the battery pack 3. Thus, the drive device 20 of the present embodiment constitutes a part of a circuit that connects the external DC power source 7 and the battery pack 3 by using the first electric motor 52R, the first inverter 30R, and the charging unit 40. The charging unit 40 includes a first main relay 42, a capacitor 44, a first charging relay 46, and a bypass relay 48.

[0043] The first main relay 42 of the charging unit 40 is electrically connected between the first electric motor 52R and the charging inlet 6. The first main relay 42 is a switch for switching the electrical connection between the drive device 20 and the external DC power source 7. The first charging relay 46 is electrically connected between the neutral point NP1 of the first electric motor 52R and the first main relay 42. The first charging relay 46 is a switch for switching the electrical connection between the neutral point NP1 and the external DC power source 7. The bypass relay 48 is electrically connected between the battery pack 3 and the first main relay 42. The bypass relay 48 is a switch for directly electrically connecting the battery pack 3 and the external DC power source 7 by bypassing the first electric motor 52R and the first inverter 30R. Each relay 42, 46, 48 of the charging unit 40 is communicably connected to a control device (not shown) of the electric vehicle 10.

[0044] When the first main relay 42 and the first charging relay 46 are turned on and the bypass relay 48 is turned off while the charging inlet 6 is connected to the external DC power source 7, the charging current of the external DC power source 7 is supplied to the battery pack 3 via the neutral point NP1 of the first electric motor 52R. Thereby, the first electric motor 52R and the first inverter 30R can function as three boost circuits connected in parallel between the charging inlet 6 and the battery pack 3. Thereby, the drive device 20 can boost the output voltage of the external DC power source 7 by using the first electric motor 52R and the first inverter 30R. Thereby, rapid charging can be executed when the output voltage of the external DC power source 7 is lower than the voltage of the battery pack 3. Thus, the charging unit 40 is connected to the neutral point NP1 of the first electric motor 52R, and the charging current is passed through the first inverter 30R via the neutral point NP1.

[0045] Also, when the first main relay 42 and the bypass relay 48 are turned on and the first charging relay 46 is turned off while the charging inlet 6 is connected to the external DC power supply 7, the charging current of the external DC power supply 7 is directly supplied to the battery pack 3 without passing through the neutral point NP1 of the first electric motor 52R. Thereby, when the output voltage of the external DC power supply 7 is equal to the voltage of the battery pack 3, it can be supplied to the battery pack 3 without boosting the output voltage of the external DC power supply 7.

[0046] As shown in FIG. 2, in this embodiment, the first inverter 30R is located on the right side of the reference plane BP of the casing 21, and the second inverter 30L is located on the left side of the reference plane BP. That is, the first inverter 30R and the second inverter 30L are distributed on both sides of the reference plane BP. Note that the first inverter 30R and the second inverter 30L may be arranged symmetrically with respect to the reference plane BP. Thereby, the centers of gravity of the first inverter 30R and the second inverter 30L can be easily brought closer to the reference plane BP. Further, the charging unit 40 is arranged on the right side of the reference plane BP. The center of gravity C10 of the charging unit 40 is located on the right side of the reference plane BP. On the other hand, an actuator 60 is arranged on the left side of the reference plane BP. The actuator 60 is a device that moves upward a lock pole 63 arranged below a motor shaft extending rightward from the second electric motor 52L among a plurality of rotating shafts 54L. The lock pole 63 meshes with a parking gear 62 arranged on the motor shaft by moving upward, thereby locking the rotation of the parking gear 62. That is, the parking gear 62 and the lock pole 63 lock the drive of the second drive unit 50L. For example, in response to the operation of the parking brake 9 (see FIG. 1) of the electric vehicle 10, the actuator 60 moves the lock pole 63 upward. Thereby, the drive of the second drive unit 50L is locked.

[0047] The overall center of gravity C20 of the actuator 60, the parking gear 62, and the lock pole 63 is located inside a triangle formed by connecting the center of gravity C21 of the actuator 60, the center of gravity C22 of the parking gear 62, and the center of gravity C23 of the lock pole 63. As described above, the actuator 60 is located on the left side of the reference plane BP, and the parking gear 62 and the lock pole 63 are arranged on the motor shaft of the second drive unit 50L located on the left side of the reference plane BP. That is, the overall center of gravity C20 of the actuator 60, the parking gear 62, and the lock pole 63 is located on the left side of the reference plane BP.

[0048] (Effects of this embodiment) Thus, in the drive device 20 of this embodiment, the center of gravity C10 of the charging unit 40 is located on the right side of the reference plane BP, and the overall center of gravity C20 of the actuator 60, parking gear 62, and lock pole 63 that lock the drive of the second drive unit 50L is located on the left side of the reference plane BP. That is, in this embodiment, the number of components arranged on the left side of the reference plane BP is larger than the number of components arranged on the right side of the reference plane BP where the charging unit 40 is located. As a result, the difference in weight on both sides of the reference plane BP is reduced. Thereby, even if the charging unit 40 used for charging the battery pack 3 is arranged on the right side of the reference plane BP, the overall center of gravity of the drive device 20 is suppressed from significantly moving toward the charging unit 40 due to the weight of the actuator 60, parking gear 62, and lock pole 63. As a result, the stability during the drive of the drive device 20 can be improved. Further, the actuator 60, parking gear 62, and lock pole 63 are components necessary for the running of the electric vehicle 10. For this reason, by using the actuator 60, parking gear 62, and lock pole 63 to bring the overall center of gravity of the drive device 20 closer to the reference plane BP, compared with a configuration including another component for adjusting the weight balance of the entire drive device 20, the weight balance of the entire drive device 20 can be adjusted with higher mass efficiency. Furthermore, by bringing the overall center of gravity of the drive device 20 closer to the reference plane BP, the weight balance of the drive device 20 can be easily adjusted. For this reason, for example, regardless of whether the driver's seat of the electric vehicle 10 is on the right or left, the drive device 20 of this embodiment can be adopted. That is, the drive device 20 can be easily adopted regardless of the position of the center of gravity of the entire mounted electric vehicle.

[0049] (Corresponding relationship) The first inverter 30R is an example of the "first power conversion unit", and the second inverter 30L is an example of the "second power conversion unit". The parking gear 62 and the lock pole 63 are examples of the "locking components".

[0050] (Second embodiment) Referring to FIG. 4, the drive device 20 of the second embodiment will be described. In the drive device 20 of this embodiment, unlike the drive device 20 of the first embodiment described above, the parking gear 62 and the lock pole 63 are arranged on the motor shaft of the first drive unit 50R. That is, in this embodiment, the parking gear 62 and the lock pole 63 lock the drive of the first drive unit 50R located on the right side of the same reference plane BP as the charging unit 40. Regarding other configurations, the drive device 20 of this embodiment has the same configuration as the drive device 20 of the first embodiment.

[0051] In the drive device 20 of this embodiment, the actuator 60 is located on the left side of the reference plane BP as in the first embodiment. Here, the weight of the actuator 60 is heavier than the total weight of the parking gear 62 and the lock pole 63. For example, the weight of the actuator 60 is 3 to 5 times the total weight of the parking gear 62 and the lock pole 63. Therefore, the overall center of gravity C30 of the actuator 60, the parking gear 62, and the lock pole 63 is located near the actuator 60 within the triangle connecting the center of gravity C31 of the actuator 60, the center of gravity C32 of the parking gear 62, and the center of gravity C33 of the lock pole 63. As a result, the center of gravity C30 is located on the left side of the reference plane BP. In the drive device 20 of this embodiment, by arranging the heavy actuator 60 on the left side of the reference plane BP, it is possible to suppress the overall center of gravity of the drive device 20 from significantly moving toward the charging unit 40 side.

[0052] (Third Embodiment) Referring to FIG. 5, the drive device 20 of the third embodiment will be described. The drive device 20 of this embodiment has basically the same configuration as the drive device 20 of the first embodiment described above, but does not include the actuator 60, the parking gear 62, and the lock pole 63. Further, in this embodiment, the first supply unit 70R (see FIG. 2) is not disposed on the right side wall of the casing 21. Further, the partition wall 27 of the casing 21 of this embodiment has a communication hole 28 that communicates the lower part of the first unit chamber 22 and the lower part of the second unit chamber 24, unlike the partition wall 26 of the first embodiment. Thereby, the heat medium H1 can move from the first unit chamber 22 to the second unit chamber 24, for example, through the communication hole 28.

[0053] The second supply unit 70L of this embodiment has the same configuration as the second supply unit 70L of the first embodiment. However, in this embodiment, the internal space of the motor shaft of the second electric motor 52L and the internal space of the motor shaft of the first electric motor 52R communicate with each other through the communication hole 53. For this reason, in this embodiment, the heat medium H1 supplied from the second supply unit 70L to the second electric motor 52 also passes through the communication hole 53 and is supplied to the first electric motor 52R. That is, in this embodiment, the heat medium H1 is supplied to the two drive units 50R and 50L by one second supply unit 70L.

[0054] In the drive device 20 of this embodiment, the second supply unit 70L is disposed on the left side of the reference plane BP, and no supply unit is disposed on the right side of the reference plane BP. For this reason, the overall center of gravity C40 of the second supply unit 70L is located on the left side of the reference plane BP. In the drive device 20 of this embodiment, by disposing one second supply unit 70L on the left side of the reference plane BP, it is possible to suppress the center of gravity of the entire drive device 20 from significantly moving toward the charging unit 40.

[0055] (Fourth Embodiment) Referring to FIG. 6, the drive device 20 of the fourth embodiment will be described. In FIGS. 6 and 7, for the sake of understanding the drawings, some of the gears of the plurality of gears 58R and 58L are not shown, but the drive device 20 of this embodiment basically has the same configuration as the drive device 20 of the first embodiment described above. Different from the drive device 20 of the third embodiment, the drive device 20 of this embodiment includes a first supply unit 90R and a second supply unit 70L. The second supply unit 70L has the same configuration as the second supply unit 70L of the first embodiment described above.

[0056] In the drive device 20 of this embodiment, the first oil pump 91R and the first oil cooler 96R of the first supply unit 90R that supplies the heat medium H1 to the first drive unit 50R are not arranged on the right side wall of the casing 21, but on the front side (i.e., the back side of the paper surface of FIG. 6) side wall. The oil pump 91R of the first supply unit 90R pumps the heat medium H1 sucked through the upstream pipe 92R through the oil cooler 96R to the downstream pipe 94R and supplies it to the first electric motor 52R. The downstream pipe 94R extends rightward along the front side wall of the casing 21 and penetrates the right side wall of the casing 21 to be connected to the first electric motor 52R.

[0057] The overall center of gravity C51 of the first supply unit 90R is located on the right side of the reference plane BP, similar to the charging unit 40. However, the first oil pump 91R and the first oil cooler 96R of the first supply unit 90R are arranged closer to the reference plane BP compared to the second oil pump 71L and the second oil cooler 76L of the second supply unit 70L. In other words, the first oil pump 91R and the first oil cooler 96R are arranged closer to the center of the casing 21 compared to the second oil pump 71L and the second oil cooler 76L. For this reason, the distance D1 between the overall center of gravity C51 of the first supply unit 90R and the reference plane BP is smaller than the distance D2 between the overall center of gravity C40 of the second supply unit 70L and the reference plane BP. For this reason, the overall center of gravity C50 of the two supply units 90R and 70L is located on the left side of the reference plane BP. In the drive device 20 of the present embodiment, by arranging the first supply unit 90R, which supplies the heat medium H1 to the first drive unit 50R, closer to the reference plane BP on the right side of the same reference plane BP as the charging unit 40, it is possible to suppress the overall center of gravity of the drive device 20 from significantly shifting towards the charging unit 40. By changing the arrangement of the first supply unit 90R and the second supply unit 70L, which have relatively close weights, it is possible to adjust the weight balance of the entire drive device 20. Further, by changing the arrangement of the first supply unit 90R, which is necessary for the running of the electric vehicle 10, it is possible to easily adjust the position of the overall center of gravity of the drive device 20. In the present embodiment, the first supply unit 90R and the second supply unit 70L are an example of "functional components".

[0058] (Fifth Embodiment) Referring to Fig. 7, the drive device 20 of the fifth embodiment will be described. The drive device 20 of this embodiment has basically the same configuration as the drive device 20 of the fourth embodiment. However, similar to the third embodiment, the partition wall 27 of the casing 21 has a communication hole 28, and the arrangement of the first supply unit 100R is different from that of the fourth embodiment. Specifically, in the first supply unit 100R of this embodiment, the first oil pump 101R and the first oil cooler 106R are located on the left side of the reference plane BP. The first supply unit 100R has two pipes 102R and 104R in addition to the first oil pump 101R and the first oil cooler 106R. However, since the weights of the first oil pump 101R and the first oil cooler 106R are extremely large compared to the weights of the two pipes 102R and 104R, the overall center of gravity C61 of the first supply unit 100R is located in the vicinity of the first oil pump 101R and the first oil cooler 106R. Therefore, in this embodiment, the overall center of gravity C61 of the first supply unit 100R is located on the left side of the reference plane BP. The overall center of gravity C60 of the two supply units 100R and 70L is located on the left side of the reference plane BP. In the drive device 20 of this embodiment, by arranging the first supply unit 100R that supplies the heat medium H1 to the first drive unit 50R on the left side of the reference plane BP, it is possible to suppress the overall center of gravity of the drive device 20 from significantly moving toward the charging unit 40 side. In this embodiment, the first supply unit 100R is an example of a "functional component".

[0059] The specific examples of the technology disclosed in this specification have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples exemplified above. The modifications of the above embodiments are listed below.

[0060] In the above-described embodiments, the parking gear 62, the lock pole 63, the actuator 60, the first supply unit 90R, the second supply unit 70L, and the first supply unit 100R are each an example of a "functional component". However, the "functional components" are not limited thereto. The "functional components" in this specification refer to the general term for components that provide a predetermined function to at least one of the first drive unit 50R and the second drive unit 50L. For example, the "functional components" may include a "shift actuator" that changes gears during the running of the electric vehicle 10. The "functional components" may include components configured to be operable independently of the drive units 50R and 50L, excluding the inverters 30R, 30L, and the charging unit 40. Further, the "functional components" may be disposed inside the casing 21 or on the outer surface of the casing 21. Also, the drive device 20 may not include the second inverter 30L.

[0061] In the above-described embodiments, the charging unit 40 was located on the right side of the reference plane BP, but the charging unit 40 may be located on the left side of the reference plane BP. In other words, the charging unit 40 may be located on the side opposite to the drive unit used for charging the battery pack 3. Also, a part of the charging unit 40 may be exposed on the left side of the reference plane BP. It is only necessary that the center of gravity C10 of the charging unit 40 is located on the right side of the reference plane BP.

[0062] For example, in the drive device 20 of the fifth embodiment, the first oil cooler 106R may be located on the left side of the reference plane BP, and the first oil pump 101R may be located on the right side of the reference plane BP. In that case, the distance between the first oil cooler 106R and the reference plane BP may be greater than the distance between the first oil pump 101R and the reference plane BP. In yet another modification, the first oil cooler 106R may be located on the right side of the reference plane BP, and the first oil pump 101R may be located on the left side of the reference plane BP.

[0063] The technical elements described in this specification or the drawings exhibit technical utility either individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies exemplified in this specification or the drawings can achieve multiple objectives simultaneously, and achieving one of those objectives by itself has technical utility.

Explanation of Signs

[0064] 2. : Vehicle body, 3: Battery pack, 4L: Left front wheel, 4R: Right front wheel, 5L, 5R: Rear wheels, 6: Charging inlet, 7: External DC power source, 8: Power cable, 9: Parking brake, 10: Electric vehicle, 14L: Left drive shaft, 14R: Right drive shaft, 20: Drive device, 21: Casing, 22: First unit chamber, 24: Second unit chamber, 26, 27: Partition wall 28, 53: Communication hole, 30R: First inverter, 30L: Second inverter, 32U: U-phase arm, 32V: V-phase arm, 32W: W-phase arm, 34: Traction smoothing capacitor, 40: Charging unit, 42: First main relay, 44: Capacitor, 46: First charging relay, 48: Bypass relay, 50R: First drive unit, 50L: Second drive unit, 52R: First electric motor, 52L: Second electric motor, 54L, 54R: Rotating shaft, 55U: U-phase coil, 55V: V-phase coil, 55W: W-phase coil, 56L, 56R: Bearing, 57R: First gear mechanism, 57L: Second gear mechanism, 58L, 58L: Gear, 60: Actuator, 62: Parking gear, 63: Lock pole, 70R, 90R, 100R: First supply unit, 70L: Second supply unit, 71R, 91R, 101R: First oil pump, 71L: Second oil pump, 72L, 72R, 92R, 102R: Upstream pipe, 74L, 74R, 94R, 104R: Downstream pipe, 76R, 96R, 106R: First oil cooler, 76L: Second oil cooler, BP: Reference plane, C10, C20, C30, C40, C50, C60: Center of gravity, D1, D2: Distance, H1: Heat medium, NP1: Neutral point

Claims

1. A drive device for driving a pair of left and right wheels mounted on a vehicle, comprising: a first drive unit having a first electric motor and driving one of the pair of left and right wheels; a second drive unit having a second electric motor and driving the other of the pair of left and right wheels; a casing housing the first drive unit and the second drive unit; a first power conversion unit electrically connected to the first electric motor; a charging unit electrically connected to the neutral point of the first electric motor and passing a current to the first power conversion unit through the neutral point; one or more functional components providing a predetermined function to at least one of the first drive unit and the second drive unit; and the first drive unit and the second drive unit are distributed on both sides of a reference plane of the casing perpendicular to the vehicle left-right direction, the center of gravity of the charging unit is located on one side of the reference plane in the vehicle left-right direction, the overall center of gravity of the one or more functional components is located on the other side of the reference plane in the vehicle left-right direction. Drive device.

2. The predetermined function includes a locking function of locking the drive of either one of the first drive unit and the second drive unit, the one or more functional components include a locking component that mechanically locks the one drive unit, and an actuator that operates the locking component. The drive device according to claim 1.

3. The one drive unit is a drive unit located on the other side of the reference plane in the vehicle left-right direction, the center of gravity of the locking component and the center of gravity of the actuator are both located on the other side of the reference plane in the vehicle left-right direction. The drive device according to claim 2.

4. The one drive unit is a drive unit located on the one side of the reference plane in the vehicle left-right direction, the center of gravity of the locking component is located on the one side of the reference plane in the vehicle left-right direction, the center of gravity of the actuator is located on the other side of the reference plane in the vehicle left-right direction, and the actuator has a weight greater than the weight of the locking component. The drive device according to claim 2.

5. The predetermined function includes a supply function of supplying a heat medium to at least one of the first drive unit and the second drive unit. ​ The one or more functional components include one or more supply units for supplying the heat medium to the at least one drive unit. The drive device according to claim 1.

6. The drive device according to claim 5, wherein the at least one drive unit is a drive unit located on the other side of the reference plane in the vehicle left-right direction.

7. The at least one drive unit is the first drive unit and the second drive unit. The one or more supply units include a first supply unit that provides the supply function to the first drive unit, and a second supply unit that provides the supply function to the second drive unit. The center of gravity of the first supply unit is located on one side of the reference plane in the vehicle left-right direction, and the center of gravity of the second supply unit is located on the other side of the reference plane in the vehicle left-right direction. The distance between the center of gravity of the first supply unit and the reference plane is smaller than the distance between the center of gravity of the second supply unit and the reference plane. The drive device according to claim 5.

8. The at least one drive unit is the first drive unit and the second drive unit. The one or more supply units include a first supply unit that provides the supply function to the first drive unit, and a second supply unit that provides the supply function to the second drive unit. The center of gravity of the first supply unit and the center of gravity of the second supply unit are both located on the other side of the reference plane in the vehicle left-right direction. The drive device according to claim 5.

9. The first drive unit is located on one side of the reference plane in the vehicle left-right direction. The drive device according to claim 1.

10. The charging unit includes a capacitor. The drive device according to claim 1.

11. The drive device further includes a second power conversion unit electrically connected to the second electric motor. The drive device according to claim 1. ​ ​

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