A drive system for a vehicle and a vehicle equipped with it.

Abstract

To protect an electric pump unit of a drive device from the external contacts.SOLUTION: A drive device for a vehicle includes: a motor; a casing that houses the motor; an electric pump unit that is attached to a lower part of the casing and circulates a heat medium in the casing; and a filter unit which is attached to the lower part of the casing and filters the heat medium circulating through the casing. At least part of the electric pump unit and at least part of the filter unit protrude to the outside of the casing respectively. On the outside of the casing, the filter unit is adjacent to the electric pump unit from the front side of the vehicle.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The technology disclosed in this specification relates to a drive device for a vehicle and a vehicle equipped with the same.

[0002] Patent Document 1 describes a drive device for a vehicle. The drive device is mounted on a vehicle such as an electric vehicle and drives a pair of front wheels or a pair of rear wheels of the vehicle. The drive device includes a motor, a casing that houses the motor, and an electric pump unit that circulates a heat medium in the casing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described drive device, at least a part of the electric pump unit protrudes outside the casing. Therefore, there is a risk that flying stones flying from the road surface or obstacles existing on the road surface may contact the electric pump unit. In particular, the electric pump unit is provided at the lower part of the casing in order to efficiently suck the heat medium in the casing. From this, there is also a risk that the above-described flying stones or obstacles may strongly contact the electric pump unit, and it is also assumed that the electric pump may be damaged. This specification provides a technology that can avoid or suppress such problems.

Means for Solving the Problems

[0005] The technology disclosed herein is embodied in a vehicle drive system. In a first embodiment, the drive system comprises a motor, a casing housing the motor, an electric pump unit mounted at the bottom of the casing for circulating a heat transfer medium within the casing, and a filter unit mounted at the bottom of the casing for filtering the heat transfer medium circulating within the casing. At least a portion of the electric pump unit and at least a portion of the filter unit each protrude outside the casing. Outside the casing, the filter unit is adjacent to the electric pump unit from the front of the vehicle.

[0006] In the configuration described above, the filter unit is adjacent to the electric pump unit from the front of the vehicle. With this configuration, the filter unit acts as a shield against flying stones and obstacles, thereby protecting the electric pump unit. [Brief explanation of the drawing]

[0007] [Figure 1] The configuration of the vehicle 10 in this embodiment is schematically shown. [Figure 2] This is a side view of the drive unit 30. [Figure 3] Enlarged view of part III in Figure 2. [Figure 4] Cross-sectional view along line IV-IV in Figure 3. [Figure 5] A schematic diagram shows the internal structure of the drive unit 30 related to the electric pump unit 50 and the filter unit 60. [Figure 6] Cross-sectional view along the line VI-VI in Figure 5. [Figure 7] An example of modification in which a filter member 74 is loaded onto the suction pipe 70 is shown. [Figure 8] Another modified example in which the inhalation tube 70 is omitted is shown. [Modes for carrying out the invention]

[0008] In a second aspect of this technology, in addition to the first aspect described above, the lowest part of the filter unit may be located below the lowest part of the electric pump unit outside the casing. With this configuration, the filter unit can more effectively perform the shield function described above.

[0009] In a third aspect of this technology, in addition to the first or second aspect described above, the electric pump unit and the filter unit may protrude from the side wall of the casing to the left or right of the vehicle outside the casing. In such a configuration, there is a high risk of the electric pump unit coming into contact with flying stones or obstacles, so the filter unit can more effectively perform its shielding function as described above.

[0010] In a fourth aspect of this technology, in addition to the third aspect described above, the dimension by which the filter unit protrudes from the side wall outside the casing may be greater than the dimension by which the electric pump unit protrudes from the side wall. With this configuration, the filter unit can more effectively perform the shield function described above.

[0011] In a fifth aspect of this technology, in addition to any of the first to fourth aspects described above, the electric pump unit may have a connector on the outside of the casing from which electrical wiring supplying power to the electric pump unit can be attached and detached. With such a configuration, the relatively vulnerable connector can be protected by the filter unit.

[0012] In a sixth aspect of this technology, in addition to any of the first to fifth aspects described above, the electric pump unit and the filter unit may be positioned below the rotation axis of the motor. The lower the position of the electric pump unit and the filter unit, the more effectively this technology can exert its effects.

[0013] In a seventh aspect of this technology, in addition to any of the first to sixth aspects described above, the drive unit may further include a reduction gear housed within the casing and mechanically connected to the motor. In this case, the electric pump unit and the filter unit may be located below the rotation axis of any gear of the reduction gear. The lower the electric pump unit and the filter unit are located, the more effectively this technology can exert its effects.

[0014] In an eighth aspect of this technology, in addition to any of the first to seventh aspects described above, the drive unit may further include a differential gear housed in the casing and mechanically connected to the motor. In this case, the electric pump unit and the filter unit may be located below the rotation axis of the differential gear. The lower the electric pump unit and the filter unit are located, the more effectively this technology can exert its effects.

[0015] In a ninth aspect of this technology, in addition to any of the first to eighth aspects described above, a suction pipe having a base end connected to the electric pump unit and a tip for drawing in the heat transfer medium within the casing may be provided inside the casing. In this case, the tip of the suction pipe may be located below the base end of the suction pipe. With this configuration, regardless of the position of the electric pump unit, the electric pump unit can reliably draw in the heat transfer medium accumulated at the bottom of the case.

[0016] In a tenth aspect of this technology, in addition to the ninth aspect described above, a strainer may be provided at the tip of the suction pipe. With this configuration, the heat transfer medium sucked in by the electric pump unit can be filtered by the strainer.

[0017] In the eleventh aspect of the present technology, in addition to the tenth aspect described above, a filter member finer than the strainer may be provided in the suction pipe between the base end and the tip end. According to such a configuration, the heat medium sucked by the electric pump unit can be further filtered by the filter member.

[0018] In the twelfth aspect of the present technology, in addition to any one of the first aspect to the eleventh aspect described above, a strainer connected to the electric pump unit via a filter member may be provided inside the casing. In this case, at least a part of the strainer may extend in a direction of displacement downward with respect to the filter member. Also with such a configuration, it becomes possible to freely change the position of the electric pump unit while maintaining the suction performance of the heat medium by the electric pump unit.

[0019] The present technology is also embodied in an electric vehicle. That is, as a thirteenth aspect, the electric vehicle includes a vehicle body, a plurality of wheels that support the vehicle body, and a drive device that drives at least one of the plurality of wheels. The drive device may be any of the drive devices described above. And outside the casing, the filter unit may be adjacent to the electric pump unit from the front in the electric vehicle.

[0020] In the fourteenth aspect of the present technology, in addition to the thirteenth aspect described above, the plurality of wheels may have a pair of front wheels and a pair of rear wheels. In this case, the drive device may be located at the front part of the vehicle body and may be configured to drive the pair of front wheels. In an electric vehicle in which the drive device is located at the front part of the vehicle body, there is a high possibility that a bouncing stone or an obstacle contacts the electric pump unit. In such an electric vehicle, the present technology can be effectively adopted.

[0021] In the fifteenth aspect of the present technology, in addition to the thirteenth aspect or the fourteenth aspect described above, the electric vehicle may further include a battery that supplies power to the drive device.

[0022] In a sixteenth aspect of this technology, the battery may be rechargeable by an external charger. That is, the electric vehicle may be a so-called battery electric vehicle. However, in another aspect, the electric vehicle may be configured such that the battery cannot be recharged by an external charger, such as a hybrid electric vehicle or a fuel cell electric vehicle.

[0023] Hereinafter, representative and non-limiting examples of the present invention will be described in detail with reference to the drawings. This detailed description is intended simply to show those skilled in the art details for carrying out preferred examples of the present invention and is not intended to limit the scope of the present invention. Furthermore, additional features and inventions disclosed below may be used separately from or in conjunction with other features and inventions to provide further improved drive systems and vehicles equipped therewith.

[0024] Furthermore, the combinations of features and processes disclosed in the following detailed description are not essential for carrying out the present invention in the broadest sense, and are described solely to illustrate representative examples of the present invention. Moreover, the various features of the representative examples described above and below, as well as the various features described in the independent and dependent claims, do not necessarily have to be combined in the same way as the examples described herein or in the order listed, in order to provide additional and useful embodiments of the present invention.

[0025] All features described herein and / or in the claims are intended to be disclosed individually and independently of each other, as limitations to the original disclosure and claimed specific subject matter, separate from the features described in the examples and / or claims. Furthermore, all descriptions of numerical ranges and groups or clusters are intended to disclose intermediate configurations as limitations to the original disclosure and claimed specific subject matter. [Examples]

[0026] Vehicle 10 of this embodiment will be described with reference to the drawings. Vehicle 10 of this embodiment is a so-called electric vehicle. Here, electric vehicle broadly means a vehicle having a motor that drives the wheels, and includes, for example, battery electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and fuel cell electric vehicles.

[0027] Here, in the figure, direction FR indicates the front of the vehicle 10 in the longitudinal direction, and direction RR indicates the rear of the vehicle 10 in the longitudinal direction. Direction LH indicates the left side of the vehicle 10 in the lateral direction, and direction RH indicates the right side of the vehicle 10 in the lateral direction. Direction UP indicates the upward direction of the vehicle 10 in the vertical direction, and direction DW indicates the downward direction of the vehicle 10 in the vertical direction. In this specification, the front, rear, left, right, upward, and downward directions of the vehicle 10 may be simply referred to as front, rear, left, right, upward, and downward.

[0028] As shown in Figure 1, the vehicle 10 comprises a body 12 and a plurality of wheels 14f, 14r supporting the body 12. The plurality of wheels 14f, 14r are each rotatably mounted to the body 12. The plurality of wheels 14f include, but are not particularly limited, a pair of front wheels 14f provided at the front of the body 12 and a pair of rear wheels 14r provided at the rear of the body 12. However, the number and arrangement of the plurality of wheels 14f, 14r are not particularly limited.

[0029] The vehicle 10 further comprises a drive unit 30. The drive unit 30 drives at least one of a plurality of wheels 14f, 14r. In this embodiment, the drive unit 30 is located at the front of the vehicle body 12 and drives a pair of front wheels 14f. The drive unit 30 is located between the pair of front wheels 14f and is connected to each of the pair of front wheels 14f via a pair of drive shafts 16. However, in another embodiment, the drive unit 30 may be located at the rear of the vehicle body 12 and drive a pair of rear wheels 14r.

[0030] The vehicle 10 further includes a battery 18 and a charging inlet 22. The battery 18 is a power source that supplies power to the drive unit 30 and is connected to the drive unit 30 via a power cable 20. The battery 18 contains multiple secondary battery cells, such as lithium-ion battery cells, and is configured to be repeatedly rechargeable. The charging inlet 22 is configured to allow the charging plug 4 of the charger 2 to be attached and detached. The charging inlet 22 is connected to the battery 18 via a charging circuit 24. This configures the battery 18 to be rechargeable by the external charger 2.

[0031] The drive unit 30 will be described in detail below. The drive unit 30 comprises a casing 32, a motor 34, and a power converter 40. The casing 32 is the outer shell of the drive unit 30 and is made of, for example, metal. The inside of the casing 32 is configured to circulate cooling oil for the purpose of cooling and lubrication. The cooling oil in this embodiment is an example of a heat transfer medium in this technology.

[0032] The motor 34 is housed within the casing 32. The motor 34 is an electric motor and is the prime mover in the drive unit 30. Power is supplied to the motor 34 from the battery 18 via the power converter 40. The power converter 40 converts the DC power supplied from the battery 18 into AC power supplied to the motor 34. The specific configuration of the motor 34 is not particularly limited. For example, the motor 34 may be a PM motor (Permanent Magnet Motor) or an induction motor. As an example, the motor 34 in this embodiment is an IPM motor (Interior Permanent Magnet Motor) in which permanent magnets are fixed to the rotor.

[0033] The drive unit 30 further comprises a reduction gear 36 and a differential 38. The reduction gear 36 is housed in a casing 32 and is mechanically connected to the motor 34. The reduction gear 36 has multiple gears and amplifies the torque output by the motor 34. The differential 38 is housed in a casing 32 and is mechanically connected to the motor 34 via the reduction gear 36. Thus, the torque output by the motor 34 is amplified by the reduction gear 36 and then distributed to the pair of front wheels 14f by the differential 38.

[0034] The specific configuration of the reduction gear 36 is not particularly limited. For example, as shown in Figure 2, the reduction gear 36 in this embodiment comprises a first gear 36a, a second gear 36b, a third gear 36c, and a fourth gear 36d. The first gear 36a is fixed to the motor 34 and driven directly by the motor 34. The first gear 36a is arranged coaxially with the motor 34, and the rotation axis C1 of the first gear 36a is located on the same straight line as the rotation axis CM of the motor 34. The second gear 36b meshes with the first gear 36a. The diameter of the second gear 36b is larger than the diameter of the first gear 36a. Thus, the first gear 36a and the second gear 36b constitute the first reduction mechanism.

[0035] The third gear 36c is fixed to the second gear 36b and rotates together with it. The third gear 36c is coaxial with the second gear 36b, and the rotation axis C3 of the third gear 36c is on the same line as the rotation axis C2 of the second gear 36b. The diameter of the third gear 36c is smaller than the diameter of the second gear 36b. The fourth gear 36d meshes with the third gear 36c. The diameter of the fourth gear 36d is larger than the diameter of the third gear 36c. Thus, the third gear 36c and the fourth gear 36d constitute a second reduction mechanism.

[0036] The specific configuration of the differential 38 is not particularly limited. For example, in this embodiment, the differential 38 is fixed to the fourth gear 36d of the reduction gear 36 and rotates together with the fourth gear 36d. The differential 38 is arranged coaxially with the fourth gear 36d, and the rotation axis CD of the differential 38 is located on the same line as the rotation axis C4 of the fourth gear 36d. A pair of front wheels 14f are connected to the differential 38 via a pair of drive shafts 16. In other embodiments, the drive unit 30 does not need to include the reduction gear 36. In this case, the differential 38 may be directly connected to the motor 34. In addition, or alternatively, the drive unit 30 does not need to include the differential 38. In this case, the motor 34 or the reduction gear 36 may be directly connected to the pair of drive shafts 16.

[0037] As shown in Figures 1-4, the drive unit 30 further comprises an electric pump unit 50 and a filter unit 60. The electric pump unit 50 is mounted at the bottom of the casing 32. The electric pump unit 50 sucks the cooling oil accumulating at the bottom of the casing 32 and pumps it to various parts of the casing 32. This causes the cooling oil to circulate within the casing 32. The electric pump unit 50 is located below the liquid level H of the cooling oil accumulating at the bottom of the casing 32. Although not particularly limited, in this embodiment the electric pump unit 50 is located on the right side wall 32r of the casing 32, and a portion of the electric pump unit 50 protrudes to the right from the right side wall 32r of the casing 32.

[0038] The filter unit 60 is mounted at the bottom of the casing 32 and is adjacent to the electric pump unit 50. The filter unit 60 filters the cooling oil circulating within the casing to remove foreign matter present in the cooling oil. The filter unit 60 is also located below the liquid level H of the cooling oil. In this embodiment, the filter unit 60, like the electric pump unit 50, is located on the right side wall 32r of the casing 32 and protrudes to the right from the right side wall 32r of the casing 32. In other embodiments, the electric pump unit 50 and the filter unit 60 are not limited to the right side wall 32r, but may be located on other parts of the casing 32, such as the left side wall.

[0039] The filter unit 60 is located in front of the electric pump unit 50 and is adjacent to the electric pump unit 50 from the front. With this configuration, the filter unit 60 acts as a shield against flying stones 100 (see Figure 3) coming from the road surface and obstacles present on the road surface. This protects the electric pump unit 50 from contact with flying stones 100 and obstacles. In particular, the electric pump unit 50 has a connector 58 located outside the casing 32. Electrical wiring that supplies power to the electric pump unit 50 is connected to this connector 58. If flying stones 100 or obstacles come into contact with such a connector 58, the electric pump unit 50 may become inoperable. With the configuration of this embodiment, the connector 58 of the electric pump unit 50 can also be protected by the filter unit 60.

[0040] As shown in Figure 3, in the drive unit 30 of this embodiment, the lowest part 60x of the filter unit 60 is located lower than the lowest part 50x of the electric pump unit 50 outside the casing 32. In addition, as shown in Figure 4, the dimension L1 by which the filter unit 60 protrudes from the right side wall 32r outside the casing 32 is greater than the dimension L2 by which the electric pump unit 50 protrudes from the right side wall 32r. With these configurations, the filter unit 60 can more effectively perform the shield function described above.

[0041] As mentioned above, the electric pump unit 50 and the filter unit 60 are mounted at the bottom of the casing 32. More specifically, as shown in Figures 3 and 4, the electric pump unit 50 and the filter unit 60 are arranged along the lower edge 32x of the right side wall 32r of the casing 32. In the casing 32, the lower edge 32x of the right side wall 32r is located at the boundary between the right side wall 32r and the bottom wall 32b, and corresponds to the very bottom of the casing 32. However, the arrangement is not limited to this, and the electric pump unit 50 and the filter unit 60 can be located at the bottom of the casing 32. For example, as shown in Figure 2, the electric pump unit 50 and the filter unit 60 may be located below the rotation axis CM of the motor 34. Alternatively, the electric pump unit 50 and the filter unit 60 may be located below the rotation axes C1-C4 of any of the gears 36a-36d of the reduction gear 36. Alternatively, the electric pump unit 50 and the filter unit 60 may be located below the rotation axis CD of the differential gear 38.

[0042] Next, with reference to Figures 5 and 6, a specific example of the structure of the electric pump unit 50 and the filter unit 60 will be described. The electric pump unit 50 comprises a pump housing 52, a pump motor 54, and a pump rotor 56. The pump motor 54 and the pump rotor 56 are housed within the pump housing 52. The pump motor 54 is a small electric motor and is the prime mover in the electric pump unit 50. The pump motor 54 is mechanically connected to the pump rotor 56 and rotates the pump rotor 56. When the pump rotor 56 rotates, the cooling oil remaining in the casing 32 is drawn into the electric pump unit 50. The drawn cooling oil is then pumped from the electric pump unit 50 to the filter unit 60 through a first oil passage 66. The first oil passage 66 is formed integrally with the casing 32, although it is not particularly limited. However, the first oil passage 66 may be made of a material independent of the casing 32, such as a resin material.

[0043] The filter unit 60 comprises a filter housing 62 and a filter material 64 housed in the filter housing 62. The filter material 64 is made of, for example, a porous material. In the filter unit 60, the cooling oil pumped from the electric pump unit 50 is configured to pass through the filter material 64. This filters the cooling oil, removing foreign matter from it. The cooling oil that has passed through the filter material 64 is supplied to other parts of the drive unit 30, such as an oil cooler (not shown), through a second oil passage 68. The second oil passage 68 is a component independent of the casing 32 and is made of, for example, a resin material. However, the second oil passage 68 may be integrated with the casing 32.

[0044] A suction pipe 70 is provided inside the casing 32. The suction pipe 70 has a base end 70a and a tip end 70b, and is a tubular member extending from the base end 70a to the tip end 70b. The base end 70a of the suction pipe 70 is connected to the electric pump unit 50, and the tip end 70b of the suction pipe 70 is submerged below the liquid level H of the cooling oil accumulating inside the casing 32. As a result, when the electric pump unit 50 is activated, the cooling oil accumulating inside the casing 32 is drawn in from the tip end 70b of the suction pipe 70. The drawn-in cooling oil is sent to the electric pump unit 50 through the suction pipe 70.

[0045] The tip 70b of the suction pipe 70 is located below the base end 70a of the suction pipe 70. With this configuration, regardless of the position of the electric pump unit 50, the electric pump unit 50 can reliably draw cooling oil from a lower position within the casing 32. In addition, the tip 70b of the suction pipe 70 is located in front of the base end 70a of the suction pipe 70. This is because the lowest point within the casing 32 is located in front of the electric pump unit 50.

[0046] A strainer 72 is attached to the tip 70b of the suction pipe 70. The strainer 72 is made of, for example, a metal mesh material. The cooling oil is filtered by the strainer 72 before being drawn into the suction pipe 70. As a result, relatively large foreign matter contained in the cooling oil is captured by the strainer 72. Here, as shown in Figure 7, a small filter member 74 may be provided in the suction pipe 70. For example, the filter member 74 is located between the strainer 72 and the tip 70b of the suction pipe 70. The filter member 74 has a finer mesh than the strainer 72 and can capture foreign matter contained in the cooling oil that has passed through the strainer 72. The filter member 74 only needs to be interposed between the strainer 72 and the electric pump unit 50 and can be installed at any position in the suction pipe 70.

[0047] As shown in Figure 8, the drive unit 30 does not necessarily need to have a suction pipe 70. That is, the filter member 74 may be connected to the electric pump unit 50 without going through the suction pipe 70. In this case, the strainer 72 may extend in a direction that displaces downward relative to the filter member 74, rather than being coaxial with the electric pump unit 50. If part or all of the strainer 72 extends in a direction that displaces downward relative to the filter member 74, the strainer 72 can be positioned below the position of the electric pump unit 50. This makes it possible to change the position of the electric pump unit 50 while maintaining the cooling oil suction performance of the electric pump unit 50. In the modified example shown in Figure 8, the filter member 74 may be further omitted. That is, the strainer 72 may be connected to the electric pump unit 50 without going through the filter member 74. Even in this case, it is preferable that part or all of the strainer 72 extends in a direction that displaces downward relative to the electric pump unit 50. [Explanation of Symbols]

[0048] 2: Charger, 4: Charging plug, 10: Vehicle, 12: Body, 14f, 14r: Wheels, 18: Battery, 22: Charging inlet, 30: Drive unit, 32: Casing, 34: Motor, 36: Reduction gear, 38: Differential gear, 40: Power converter, 50: Electric pump unit, 50x: Bottom of electric pump unit, 58: Connector of electric pump unit, 60: Filter unit, 70: Intake pipe, 70a: Base end of intake pipe, 70b: Tip of intake pipe, 72: Strainer, 74: Filter component, 100: Stone chips

Claims

1. A drive system for a vehicle, Motor and, The casing housing the motor, An electric pump unit is attached to the lower part of the casing and circulates the heat transfer medium inside the casing, A filter unit is attached to the lower part of the casing and filters the heat transfer medium circulating within the casing, Equipped with, At least a portion of the electric pump unit and at least a portion of the filter unit each protrude to the outside of the casing. Outside the casing, the filter unit is adjacent to the electric pump unit from the front of the vehicle, Drive unit.

2. The drive device according to claim 1, wherein, outside the casing, the lowest part of the filter unit is located lower than the lowest part of the electric pump unit.

3. The drive device according to claim 1 or 2, wherein, outside the casing, the electric pump unit and the filter unit protrude from the side wall of the casing to the left or right of the vehicle.

4. The drive device according to claim 3, wherein, outside the casing, the dimension by which the filter unit protrudes from the side wall is greater than the dimension by which the electric pump unit protrudes from the side wall.

5. The drive device according to claim 1 or 2, wherein the electric pump unit has a connector on the outside of the casing that allows for the attachment and detachment of electrical wiring for supplying power to the electric pump unit.

6. The drive device according to claim 1 or 2, wherein the electric pump unit and the filter unit are located below the rotation axis of the motor.

7. The reduction gear, which is housed within the casing and mechanically connected to the motor, further comprises The drive device according to claim 1 or 2, wherein the electric pump unit and the filter unit are located below the rotation axis of at least one gear of the reduction gear.

8. The casing is housed inside the differential gear which is mechanically connected to the motor, The drive device according to claim 1 or 2, wherein the electric pump unit and the filter unit are located below the rotation axis of the differential.

9. Inside the casing, there is a suction pipe having a base end connected to the electric pump unit and a tip end that draws in the heat transfer medium within the casing. The drive device according to claim 1 or 2, wherein the tip of the suction tube is located below the base end of the suction tube.

10. The drive device according to claim 9, wherein a strainer is provided at the tip of the suction tube.

11. The drive device according to claim 10, wherein the intake pipe is provided with a filter member for filtering the heat transfer medium that has passed through the strainer.

12. A strainer connected to the electric pump unit via a filter member is provided inside the casing. The drive device according to claim 1 or 2, wherein at least a portion of the strainer extends in a direction that displaces downward relative to the filter member.

13. It is a vehicle, The car body and, Multiple wheels supporting the vehicle body, A drive device according to claim 1 that drives at least one of the plurality of wheels, Equipped with, Outside the casing, the filter unit is adjacent to the electric pump unit from the front of the vehicle, vehicle.

14. The aforementioned plurality of wheels have a pair of front wheels and a pair of rear wheels. The vehicle according to claim 13, wherein the drive unit is located at the front of the vehicle body and drives the pair of front wheels.

15. The vehicle according to claim 13 or 14, further comprising a battery that supplies power to the drive unit.

16. The vehicle according to claim 15, wherein the battery is rechargeable by an external charger.

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