Electric vehicles

Abstract

The drive unit is positioned close to the steering gear unit. [Solution] The electric vehicle comprises a vehicle body, a plurality of wheels including a pair of front wheels, a drive unit, a steering gear unit positioned in front of the vehicle relative to the drive unit and extending along the vehicle width direction, which steers the pair of front wheels, a steering shaft extending from the steering gear unit toward the rear of the vehicle, which transmits steering operations by the user to the steering gear unit, and a plurality of mounts that support the drive unit on the vehicle body. The plurality of mounts include a first mount attached to one side of the housing in the vehicle width direction. A portion of the steering shaft is positioned above the first mount.

Description

Technical Field

[0001] The technology disclosed in this specification relates to electric vehicles.

Background Art

[0002] Patent Document 1 describes an electric vehicle. This electric vehicle includes a vehicle body, a plurality of wheels supported by the vehicle body and including a pair of front wheels, a drive unit having a motor for driving the pair of front wheels, and a steering gear unit that is disposed in front of the drive unit in the vehicle front direction and extends along the vehicle width direction to steer the pair of front wheels, and a steering shaft that extends from the steering gear unit toward the rear of the vehicle and transmits a steering operation by a user to the steering gear unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In electric vehicles like the one described above, the space required to house the steering gear unit can be reduced by positioning the drive unit closer to the steering gear unit. However, the drive unit is relatively heavy and is supported by multiple mounts on the vehicle body, and each of these mounts is also relatively large. Therefore, if the steering gear unit is positioned in front of the drive unit, the steering shaft extending from the steering gear unit towards the rear of the vehicle may interfere with a mount on the side of the drive unit. Alternatively, the steering gear unit may interfere with a mount on the front of the drive unit in the longitudinal direction of the vehicle. In this case, it becomes difficult to position the drive unit closer to the steering gear unit.

[0005] In light of the above circumstances, this specification provides a technique for positioning the drive unit closer to the steering gear unit. [Means for solving the problem]

[0006] The technology disclosed herein is embodied in an electric vehicle. In a first embodiment, the electric vehicle includes a vehicle body; a drive unit having a plurality of wheels supported by the vehicle body, including a pair of front wheels; a motor for driving the pair of front wheels; a differential gear mechanism for distributing the torque output by the motor to the pair of front wheels; and a housing for housing the motor and the differential gear mechanism; a steering gear unit positioned forward of the vehicle relative to the drive unit and extending along the vehicle width direction for steering the pair of front wheels; a steering shaft extending from the steering gear unit toward the rear of the vehicle for transmitting steering operations by the user to the steering gear unit; and a plurality of mounts for supporting the drive unit on the vehicle body. The plurality of mounts include a first mount attached to one side of the housing in the vehicle width direction. A portion of the steering shaft is positioned above the first mount.

[0007] In the electric vehicle described above, the drive unit is supported by the vehicle body by multiple mounts, including a first mount. The first mount is attached to one side of the drive unit housing in the vehicle width direction, and a portion of the steering shaft is positioned above the first mount. That is, the first mount and the steering shaft are positioned to overlap in the vehicle's vertical direction. With this configuration, even if the steering shaft extends from the steering gear unit toward the rear of the vehicle, interference between the steering shaft and the first mount supporting the drive unit can be avoided. This allows the drive unit to be positioned closer to the steering gear unit.

[0008] In a second embodiment, the electric vehicle may further include a drive shaft extending from one side of the housing in the vehicle width direction toward one of a pair of front wheels, as in the first embodiment. In this case, the first mount may be located behind the drive shaft. With this configuration, the first mount can be positioned at the rear of the drive unit. Generally, a steering shaft extending from a steering gear unit is displaced upward as it moves toward the rear of the vehicle. Therefore, if the first mount is positioned at the rear of the drive unit, the steering shaft can be positioned above the first mount with ample clearance.

[0009] In a third embodiment, in the first or second embodiment, the motor may be arranged coaxially with the differential gear mechanism in the drive unit. With this configuration, the drive unit can be made smaller compared to the case in which the motor is not arranged coaxially with the differential gear mechanism. By making the drive unit smaller, the position of the first mount can be lowered. This allows the steering shaft to be positioned above the first mount with ample clearance.

[0010] In a fourth embodiment, in any of the first to third embodiments, the electric vehicle may further include power components. In this case, the power components may be located inward in the vehicle width direction from the steering shaft. Such a configuration makes it possible to reduce the size of the space required to house the steering shaft and the power components.

[0011] In the fifth embodiment, in the fourth embodiment, the power component may be a high-voltage component that constitutes part of the air conditioning system.

[0012] In the sixth embodiment, the electric vehicle may further include a temperature control unit in any of the first to fifth embodiments. The temperature control unit, as used herein, means a unit that is connected to components mounted on the electric vehicle via piping and controls the circulation of a heat transfer medium between multiple components. In this case, the temperature control unit may be positioned inward in the vehicle width direction from the steering shaft. With such a configuration, the space required to house the steering shaft and the temperature control unit can be reduced.

[0013] In the seventh embodiment, in any of the first to sixth embodiments, the plurality of mounts may further include a second mount attached to the other side of the housing in the vehicle width direction, and a third mount provided further forward of the vehicle than the first and second mounts. With such a configuration, the drive unit can be supported by the vehicle body by the three mounts.

[0014] In the eighth aspect, in the seventh aspect, a portion of the steering gear unit may be positioned above the third mount. With this configuration, even if the steering gear unit, which is positioned in front of the drive unit, extends along the vehicle width direction, interference between the steering gear unit and the third mount supporting the drive unit can be avoided.

[0015] In a ninth embodiment, the steering gear unit in the eighth embodiment may include a rack shaft slidably supported along the vehicle width direction and a casing housing the rack shaft. In this case, a portion of the casing may be positioned above the third mount. In other embodiments, the steering gear unit does not necessarily include a rack shaft and / or a casing. The specific configuration of the steering gear unit is not particularly limited in this art.

[0016] The technologies disclosed herein are also embodied in other electric vehicles. In a tenth embodiment, the electric vehicle comprises a vehicle body; a drive unit having a vehicle body and a plurality of wheels including a pair of front wheels, a motor for driving the pair of front wheels, a differential gear mechanism for distributing the torque output by the motor to the pair of front wheels, and a housing for housing the motor and the differential gear mechanism; a steering gear unit positioned forward of the vehicle relative to the drive unit and extending along the vehicle width direction for steering the pair of front wheels; and a plurality of mounts for supporting the drive unit on the vehicle body. The plurality of mounts include a third mount attached to the front of the housing in the vehicle longitudinal direction. A portion of the steering gear unit is positioned above the third mount.

[0017] In the electric vehicle described above, the drive unit is supported by the vehicle body by multiple mounts, including a third mount. The third mount is attached to the front of the housing in the vehicle's longitudinal direction, and a portion of the steering gear unit is positioned above the third mount. That is, the third mount and the steering gear unit are positioned to overlap in the vehicle's vertical direction. With this configuration, even if the steering gear unit, which is positioned in front of the drive unit, extends along the vehicle's width direction, the steering gear unit can avoid interfering with the third mount, which is provided on the front of the drive unit's housing in the vehicle's longitudinal direction. This allows the drive unit to be positioned closer to the steering gear unit.

Brief Description of the Drawings

[0018] [Figure 1] A diagram schematically showing the configuration of the electric vehicle 10 of the embodiment. [Figure 2] A plan view for explaining the positional relationship among the front drive unit 18, the steering gear unit 76, and the plurality of mounts 110a, 110b, 110c. [Figure 3] A side view for explaining the positional relationship among the front drive unit 18, the steering gear unit 76, and the plurality of mounts 110a, 110b, 110c. [Figure 4] A front view for explaining the positional relationship among the front drive unit 18, the steering gear unit 76, and the plurality of mounts 110a, 110b, 110c. [Figure 5] A diagram showing a skeleton view of the front drive unit 18. [Figure 6] A diagram schematically showing the configuration of the steering gear unit 76. Note that the intermediate shaft 82 is also shown together.

Modes for Carrying Out the Invention

[0019] Referring to the drawings, the electric vehicle 10 of the embodiment will be described. The electric vehicle 10 is a so-called automobile, which is a vehicle that travels on a road surface. The electric vehicle 10 is not limited to being operated by a user, and may be remotely operated by an external device or may be self-driving.

[0020] Here, in the drawings, the direction FR indicates the front in the longitudinal direction (or the front-rear direction) of the electric vehicle 10, and the direction RR indicates the rear in the longitudinal direction of the electric vehicle 10. Also, the direction LH indicates the left in the vehicle width direction (or the left-right direction) of the electric vehicle 10, and the direction RH indicates the right in the vehicle width direction of the electric vehicle 10. Further, the direction UP indicates the upper side in the height direction (or the up-down direction) of the electric vehicle 10, and the direction DW indicates the lower side in the height direction of the electric vehicle 10.

[0021] As shown in FIG. 1, the electric vehicle 10 includes a vehicle body 12 and a plurality of wheels 14f, 14r. The vehicle body 12 includes a vehicle body main body 12a and a suspension member 12b. The vehicle body main body 12a forms the skeletal structure of the vehicle body 12. The suspension member 12b is supported by the vehicle body main body 12a. Although not particularly limited, the suspension member 12b includes a pair of side rails extending along the vehicle longitudinal direction and a pair of cross members extending along the vehicle width direction. The vehicle body 12 has a passenger compartment 12c which is a space for carrying passengers. The plurality of wheels 14f, 14r are supported by the vehicle body 12. The plurality of wheels 14f, 14r are rotatably attached to the vehicle body 12. The plurality of wheels 14f, 14r include a pair of front wheels 14f located at the front of the vehicle body 12 and a pair of rear wheels 14r located at the rear of the vehicle body 12. The pair of front wheels 14f are arranged coaxially with each other, and the pair of rear wheels 14r are also arranged coaxially with each other. Note that the number of the wheels 14f, 14r is not limited to four. Also, although not particularly limited, the vehicle body 12 is made of a metal such as a steel material or an aluminum alloy.

[0022] As shown in FIG. 1, the electric vehicle 10 further includes a battery pack 16, a front drive unit 18, and a rear drive unit 20. The battery pack 16 incorporates, for example, a plurality of secondary battery cells and is configured to be repeatedly charged by external power. The battery pack 16 supplies power to each of the front drive unit 18 and the rear drive unit 20. The battery pack 16 is arranged below the passenger compartment 12c. The front drive unit 18 is arranged at the front of the vehicle body 12. The rear drive unit 20 is arranged at the rear of the vehicle body 12.

[0023] The front drive unit 18 drives a pair of front wheels 14f, and the rear drive unit 20 drives a pair of rear wheels 14r. Although the front drive unit 18 and the rear drive unit 20 drive different pairs of wheels 14f and 14r, they share a common structure. Therefore, the following description will focus on the configuration related to the front drive unit 18, and the description of the configuration related to the rear drive unit 20 will be omitted.

[0024] As shown in Figure 2-4, the electric vehicle 10 further comprises a plurality of mounts 110a, 110b, and 110c. The plurality of mounts 110a, 110b, and 110c support the front drive unit 18 on the vehicle body 12. The plurality of mounts 110a, 110b, and 110c are attached to the housing 32 of the front drive unit 18. The plurality of mounts 110a, 110b, and 110c include a first mount 110a, a second mount 110b, and a third mount 110c. The first mount 110a and the second mount 110b are attached to the vehicle body 12a. The third mount 110c is attached to the suspension member 12b. However, the portion of the vehicle body 12 to which the plurality of mounts 110a, 110b, and 110c are attached is not particularly limited. That is, in other embodiments, the first mount 110a and the second mount 110b may be attached to other parts of the vehicle body 12 excluding the main body 12a. Also, the third mount 110c may be attached to other parts of the vehicle body 12 excluding the suspension member 12b.

[0025] The first mount 110a is attached to one side of the housing 32 in the vehicle width direction (i.e., the left side) 32a. The second mount 110b is attached to the other side of the housing 32 in the vehicle width direction (i.e., the right side) 32b. The third mount 110c is located further forward than the first mount 110a and the second mount 110b. The third mount 110c is attached to the front of the housing 32 in the vehicle longitudinal direction. In this embodiment, the third mount 110c is attached to the front surface 32c of the housing 32. However, the third mount 110c does not necessarily have to be attached to the front surface 32c of the housing 32. In other embodiments, the third mount 110c may be located on the lower surface of the front of the housing 32.

[0026] Each of the multiple mounts 110a, 110b, and 110c comprises a unit-side mounting member 112a, 112b, and 112c, a vehicle body-side mounting member 114a, 114b, and 114c, and a vibration-damping member 116a, 116b, and 116c. The unit-side mounting members 112a, 112b, and 112c are attached to one side of the housing 32 of the front drive unit 18 (in this embodiment, the left side 32a, the right side 32b, or the front surface 32c). The vehicle body-side mounting members 114a, 114b, and 114c are attached to the vehicle body 12 (in this embodiment, the main body 12a or the suspension member 12b). The vibration-damping members 116a, 116b, and 116c are interposed between the unit-side mounting members 112a, 112b, and 112c and the vehicle-side mounting members 114a, 114b, and 114c. The vibration-damping members 116a, 116b, and 116c suppress the transmission of vibrations from the front drive unit 18 from the unit-side mounting members 112a, 112b, and 112c to the vehicle-side mounting members 114a, 114b, and 114c. This suppresses the transmission of vibrations from the front drive unit 18 to the vehicle body 12. Although not particularly limited, the vibration-damping members 116a, 116b, and 116c are made of an elastic material. In this embodiment, the unit-side mounting members 112a, 112b, and 112c include shafts 113a, 113b, and 113c. The vehicle body mounting members 114a, 114b, and 114c are provided with through holes 115a, 115b, and 115c. Shafts 113a, 113b, and 113c are positioned inside the through holes 115a, 115b, and 115c. Vibration damping members 116a, 116b, and 116c are interposed between the shafts 113a, 113b, and 113c and the through holes 115a, 115b, and 115c.

[0027] The first mount 110a and the second mount 110b have symmetrical shapes. Therefore, the unit-side mounting members 112a, 112b, vehicle-side mounting members 114a, 114b, and vibration-damping members 116a, 116b of these two mounts 110a and mount 110b have symmetrical shapes. The third mount 110c has a different shape from the first mount 110a and the second mount 110b. Therefore, the unit-side mounting member 112c, vehicle-side mounting member 114c, and vibration-damping member 116c of the third mount 110c each have a different shape from the unit-side mounting members 112a, 112b, vehicle-side mounting members 114a, 114b, and vibration-damping members 116a, 116b of the other two mounts 110a and 110b.

[0028] As shown in Figures 2, 3, and 5, the electric vehicle 10 further comprises a left front drive shaft 22 and a right front drive shaft 24. The left front drive shaft 22 is located between the front drive unit 18 and one of the pair of front wheels 14f (i.e., the left front wheel 14f). The left front drive shaft 22 extends from the left side surface 32a of the housing 32 toward the left front wheel 14f. The front drive unit 18 is connected to the left front wheel 14f via the left front drive shaft 22. The right front drive shaft 24 is located between the front drive unit 18 and the other of the pair of front wheels 14f (i.e., the right front wheel 14f). The front drive unit 18 is connected to the right front wheel 14f via the right front drive shaft 24. The right front drive shaft 24 extends from the right side surface 32b of the housing 32 toward the right front wheel 14f.

[0029] As shown in Figures 2 and 5, the front drive unit 18 comprises a motor 26, a gear mechanism 28, an electrical unit 30, a housing 32, a left output shaft 34, and a right output shaft 36. The motor 26 is a drive motor that drives a pair of front wheels 14f, and in this embodiment, it is a motor driven by three-phase AC power. The gear mechanism 28 distributes the driving force of the motor 26 to the pair of front wheels 14f. The motor 26 is connected to the left output shaft 34 and the right output shaft 36, respectively, via the gear mechanism 28. The left output shaft 34 is connected to the left front wheel 14f via the left front drive shaft 22. The right output shaft 36 is connected to the right front wheel 14f via the right front drive shaft 24. In this way, the motor 26 is connected to the pair of front wheels 14f via the gear mechanism 28, the output shafts 34 and 36, and the front drive shafts 22 and 24. This allows the motor 26 to drive the pair of front wheels 14f. In this embodiment, the motor 26 is arranged coaxially with the gear mechanism 28.

[0030] The electrical unit 30 controls the power supplied to the motor 26. In this embodiment, the electrical unit 30 has a built-in inverter and controls the power transmitted between the battery pack 16 and the motor 26. The electrical unit 30 is located behind the motor 26 and the gear mechanism 28. The electrical unit 30 may further include a DC-DC converter.

[0031] As shown in Figure 2-5, the housing 32 is a housing component. The housing 32 houses the motor 26, the gear mechanism 28, and the electrical unit 30. The housing 32 is composed of one or more housing components.

[0032] As shown in Figure 5, the motor 26 comprises a rotor 46, a stator 48, and a rotor shaft 50. The rotor 46 is rotatably supported in the housing 32 around a rotation axis R1. The stator 48 generally has a cylindrical shape with the rotation axis R1 as its central axis. The stator 48 is fixed to the inner wall of the housing 32. The stator 48 is located radially outward from the rotor 46. The rotor shaft 50 is connected to the rotor 46 and rotates together with the rotor 46. The rotor shaft 50 has a through hole 50a extending along the direction of the rotation axis R1. The right output shaft 36 is located within the through hole 50a.

[0033] As shown in Figure 5, the gear mechanism 28 comprises a planetary gear mechanism 52 and a differential gear mechanism 54. The planetary gear mechanism 52 reduces the rotation of the rotor shaft 50 of the motor 26. The differential gear mechanism 54 distributes the torque of the motor 26 transmitted via the planetary gear mechanism 52 to a pair of front wheels 14f. In this embodiment, the differential gear mechanism 54 is arranged coaxially with the motor 26.

[0034] As shown in Figure 5, the planetary gear mechanism 52 comprises a sun gear 56, a plurality of stepped pinion gears 58, a ring gear 60, and a carrier 62. The sun gear 56 is connected to the rotor shaft 50 of the motor 26 and rotates together with the rotor shaft 50. Each of the plurality of stepped pinion gears 58 includes a large-diameter pinion gear 58a and a small-diameter pinion gear 58b. The diameter of the small-diameter pinion gear 58b is smaller than the diameter of the large-diameter pinion gear 58a. The large-diameter pinion gear 58a meshes with the sun gear 56. The small-diameter pinion gear 58b meshes with the ring gear 60. Each of the plurality of stepped pinion gears 58 can rotate on its own axis and revolve around the sun gear 56 and the ring gear 60. The ring gear 60 is fixed to the housing 32. The carrier 62 rotatably supports each of the multiple stepped pinion gears 58. The carrier 62 is also rotatably supported relative to the housing 32 around the rotation axis R1. As a result, the carrier 62 can rotate around the rotation axis R1 as the multiple stepped pinion gears 58 revolve.

[0035] As shown in Figure 5, the differential gear mechanism 54 comprises a differential case 64, a pinion shaft 66, differential pinion gears 68 and 70, a left side gear 72, and a right side gear 74. The differential case 64 is rotatably supported on the housing 32 around a rotation axis R1. The differential case 64 is connected to the carrier 62 of the planetary gear mechanism 52 and rotates together with the carrier 62. The pinion shaft 66, differential pinion gears 68 and 70, left side gear 72, and right side gear 74 are housed within the differential case 64.

[0036] The pinion shaft 66 is connected to the differential case 64 and rotates together with the differential case 64. The pinion shaft 66 extends in a direction perpendicular to the direction of the rotation axis R1. Each of the differential pinion gears 68 and 70 is rotatably supported relative to the pinion shaft 66, around the axis of the pinion shaft 66. The left side gear 72 and the right side gear 74 are coaxially arranged and face each other. The left side gear 72 meshes with each of the differential pinion gears 68 and 70. The left side gear 72 is connected to the left output shaft 34. The right side gear 74 meshes with each of the pair of differential pinion gears 68 and 70. The right side gear 74 is connected to the right output shaft 36.

[0037] The power transmission flow in the front drive unit 18 described above will now be explained. The rotational force of the rotor shaft 50 of the motor 26 is transmitted to the stepped pinion gear 58 as input to the rotation of the sun gear 56. The stepped pinion gear 58, having received the input, rotates on its own axis and revolves along the inner circumference of the fixed ring gear 60, receiving the reaction force of the ring gear 60. The revolving motion of the stepped pinion gear 58 is output as the rotation of the carrier 62. Within the differential case 64, which rotates together with the carrier 62, power is transmitted from the differential pinion gears 68 and 70 to the respective side gears 72 and 74. The power transmitted to each side gear 72 and 74 causes a corresponding front drive shaft 22 or 24 to rotate. Thus, in the front drive unit 18 of this embodiment, the sun gear 56 is the input element, the ring gear 60 is the reaction force element, and the carrier 62 is the output element.

[0038] Furthermore, the front drive unit 18 and the rear drive unit 20 may be equipped with other drive sources such as an engine in addition to the motor 26. Also, the electric vehicle 10 may be equipped with other power sources such as a fuel cell unit or solar panels in addition to, or instead of, the battery pack 16. Thus, the electric vehicle 10 is not limited to a battery-powered electric vehicle, but may be other types of electric vehicles such as hybrid vehicles, fuel cell vehicles, or solar cars.

[0039] As shown in Figure 1, the electric vehicle 10 further comprises a steering gear unit 76, a steering wheel 78, and a steering shaft 80 including an intermediate shaft 82. The steering gear unit 76 steers a pair of front wheels 14f. The steering gear unit 76 is positioned in front of the vehicle relative to the front drive unit 18 and extends along the vehicle width direction. The steering wheel 78 is positioned in front of the driver's seat and is operated by the user. The steering shaft 80 transmits the steering operation by the user to the steering gear unit 76. The steering shaft 80 extends from the steering gear unit 76 toward the rear of the vehicle. In this embodiment, the electric vehicle 10 is left-hand drive, so the steering shaft 80 extends from the left side of the steering gear unit 76 toward the rear of the vehicle. The rear end of the steering shaft 80 is connected to the steering wheel 78. The front end of the steering shaft 80 is connected to the steering gear unit 76. As a result, the steering shaft 80 can transmit the rotational operation of the steering wheel 78, which is the steering operation performed by the user, to the steering gear unit 76. In other embodiments, the steering shaft 80 does not have to include the intermediate shaft 82 and may consist of a single shaft.

[0040] As shown in Figures 2-4 and 2-6, the steering gear unit 76 comprises a casing 84, a pinion shaft 86, a rack shaft 88, a motor 90, and a transmission mechanism 92. The casing 84 comprises a first casing 84a, a second casing 84b, a third casing 84c, and a fourth casing 84d. The casing 84 is composed of one or more casing members.

[0041] The pinion shaft 86 is housed within the first casing 84a and is rotatably supported within the first casing 84a. The pinion shaft 86 is connected to the steering shaft 80. In this embodiment, the rear end of the pinion shaft 86 is connected to the front end of the steering shaft 80. This allows the pinion shaft 86 to rotate in response to the user's rotational operation of the steering wheel 78. A pinion gear portion 86a is formed on the outer circumferential surface of the front end of the pinion shaft 86. The rack shaft 88 is housed within the second casing 84b and is slidably supported within the second casing 84b along the vehicle width direction. A rack gear portion 88a is formed on the outer circumferential surface of the rack shaft 88. The rack gear portion 88a meshes with the pinion gear portion 86a. This causes the rack shaft 88 to move linearly in the axial direction in response to the rotational motion of the pinion shaft 86. The linear motion of the rack shaft 88 is transmitted to the pair of front wheels 14f. Therefore, when the rack shaft 88 moves along the axial direction, the pair of front wheels 14f are steered. Tie rods and knuckles may be provided between the rack shaft 88 and the pair of front wheels 14f.

[0042] Motor 90 is a motor that serves as the drive source for the rack shaft 88, and in this embodiment, it is a motor driven by three-phase AC power. The rotation axis R2 of motor 90 is arranged parallel to the rack shaft 88. The operation of motor 90 is controlled by a control unit (not shown). By driving the rack shaft 88, motor 90 can assist the user in rotating the steering wheel 78. Furthermore, if the electric vehicle 10 is capable of autonomous driving, the rack shaft 88 can be driven without requiring the user to rotate the steering wheel 78. Motor 90 is housed in a third casing 84c.

[0043] The transmission mechanism 92 is interposed between the motor 90 and the rack shaft 88. The transmission mechanism 92 is configured to convert the rotational motion of the motor 90 into linear motion of the rack shaft 88. That is, as the motor 90 rotates, the rack shaft 88 moves along the axial direction. The specific configuration of the transmission mechanism 92 is not particularly limited. As an example, the transmission mechanism 92 of this embodiment comprises a belt mechanism 94 and a linear motion mechanism 96. The belt mechanism 94 is interposed between the motor 90 and the linear motion mechanism 96 and transmits the rotational motion of the motor 90 to the linear motion mechanism 96. The linear motion mechanism 96 is interposed between the belt mechanism 94 and the rack shaft 88 and converts the rotational motion input from the belt mechanism 94 into linear motion of the rack shaft 88. The belt mechanism 94 and the linear motion mechanism 96 are housed in a fourth casing 84d.

[0044] As shown in Figure 6, the belt mechanism 94 comprises a pair of pulleys 98, 100 and a belt 102. The belt 102 is wrapped between the pair of pulleys 98, 100. The pair of pulleys 98, 100 includes a drive pulley 98 and a driven pulley 100. The drive pulley 98 is connected to and driven by a motor 90. The driven pulley 100 is positioned coaxially with the rack shaft 88. Although not particularly limited, the diameter of the driven pulley 100 is larger than the diameter of the drive pulley 98. Thus, the belt mechanism 94 also functions as a reduction gear mechanism.

[0045] As shown in Figure 6, the linear motion mechanism 96 comprises a ball nut 104, a plurality of balls 106, and a bearing 108. The ball nut 104 has a cylindrical shape. The ball nut 104 is arranged to surround the rack shaft 88. A driven pulley 100 is fixed coaxially to the ball nut 104. As a result, the ball nut 104 rotates in conjunction with the rotation of the driven pulley 100. A groove 104a is formed on the inner circumferential surface of the ball nut 104. A groove 88b is formed on the outer circumferential surface of the rack shaft 88. The plurality of balls 106 are arranged between the groove 104a of the ball nut 104 and the groove 88b of the rack shaft 88. As a result, the ball nut 104 is screwed onto the rack shaft 88 via the plurality of balls 106. The ball nut 104 is rotatably supported by the bearing 108 relative to the fourth casing 84d.

[0046] In the transmission mechanism 92 described above, when the motor 90 rotates, the drive pulley 98 rotates. The rotation of the drive pulley 98 is transmitted to the driven pulley 100 via the belt 102, causing the driven pulley 100 and the ball nut 104 to rotate. In this embodiment, since the diameter of the driven pulley 100 is larger than the diameter of the drive pulley 98, the rotational speed of the driven pulley 100 and the ball nut 104 is slower than the rotational speed of the drive pulley 98. The rotational speed of the drive pulley 98 relative to the rotational speed of the driven pulley 100 and the ball nut 104 changes according to the ratio of the diameter of the drive pulley 98 to the diameter of the driven pulley 100. Since the ball nut 104 rotates relative to the rack shaft 88, the multiple balls 106 interposed between the ball nut 104 and the rack shaft 88 receive a load from the ball nut 104 and the rack shaft 88 and circulate indefinitely within the rolling path A. As the ball 106 circulates indefinitely, the torque applied to the ball nut 104 is converted into a force applied to the rack shaft 88 in the axial direction. In this way, the rack shaft 88 moves linearly in the axial direction relative to the ball nut 104 in response to the rotational motion of the motor 90. This axial force applied to the rack shaft 88 becomes an assist force, which helps to steer the pair of front wheels 14f.

[0047] As shown in Figures 2 and 3, a portion of the steering shaft 80 (more specifically, the intermediate shaft 82) is positioned above the first mount 110a. That is, the first mount 110a and the steering shaft 80 are positioned to overlap in the vertical direction of the vehicle. With this configuration, even if the steering shaft 80 extends from the steering gear unit 76 toward the rear of the vehicle, interference between the steering shaft 80 and the first mount 110a supporting the front drive unit 18 can be avoided. This allows the front drive unit 18 to be positioned closer to the steering gear unit 76.

[0048] As shown in Figure 3, the first mount 110a is located behind the left front drive shaft 22. With this configuration, the first mount 110a can be positioned at the rear of the front drive unit 18. Generally, the steering shaft 80 extending from the steering gear unit 76 is displaced upward as it moves towards the rear of the vehicle. Therefore, when the first mount 110a is positioned at the rear of the front drive unit 18, the steering shaft 80 can be positioned above the first mount 110a with ample clearance.

[0049] While not particularly limited, as shown in Figure 5, in the front drive unit 18, the motor 26 is arranged coaxially with the differential gear mechanism 54. With this configuration, the front drive unit 18 can be made smaller compared to when the motor 26 is not arranged coaxially with the differential gear mechanism 54. By making the front drive unit 18 smaller, the position of the first mount 110a can be lowered. This allows the steering shaft 80 to be positioned above the first mount 110a with ample clearance.

[0050] As shown in Figure 2-4, the multiple mounts 110a, 110b, and 110c further include a second mount 110b attached to the other side of the housing 32 in the vehicle width direction, and a third mount 110c provided further forward than the first mounts 110a and the second mounts 110b. With this configuration, the three mounts 110a, 110b, and 110c can support the front drive unit 18 to the vehicle body 12.

[0051] As shown in Figures 3 and 4, a portion of the steering gear unit 76 is positioned above the third mount 110c. With this configuration, even if the steering gear unit 76, which is positioned in front of the front drive unit 18, extends along the vehicle width direction, interference between the steering gear unit 76 and the third mount 110c supporting the front drive unit 18 can be avoided.

[0052] In relation to the above, as shown in Figures 3 and 4, a portion of the second casing 84b of the steering gear unit 76 is positioned above the third mount 110c in this embodiment. The rack shaft 88 is housed inside the second casing 84b. Note that the steering gear unit 76 does not necessarily have to include the rack shaft 88 and / or the casing 84. In this technology, the specific configuration of the steering gear unit 76 is not particularly limited.

[0053] As an example, as shown in Figure 3, the electric vehicle 10 further includes a power component 118. The power component 118 is a high-voltage component that constitutes part of the air conditioning system. Here, high voltage refers to an operating voltage exceeding 60V DC or an operating voltage exceeding 25V AC (RMS). Although not particularly limited, the power component 118 in this embodiment is an Electric High Voltage Heater (HVH), which converts DC power supplied from the battery pack 16 into heat to heat a heat transfer medium for heating, for example, the passenger compartment 12c. The power component 118 is located above the front drive unit 18. The power component 118 and the front drive unit 18 are arranged to overlap in the vertical direction of the vehicle. The power component 118 is located inward in the vehicle width direction from the steering shaft 80. With this configuration, the space required to house the steering shaft 80 and the power component 118 can be reduced in size.

[0054] As an example, as shown in Figures 3 and 4, the electric vehicle 10 further includes a temperature control unit 120. Here, the temperature control unit 120 refers to a unit that is connected to a plurality of components mounted on the electric vehicle 10 via piping 120a and controls the circulation of a heat transfer medium between the plurality of components. In this embodiment, the temperature control unit 120 is connected via piping 120a to the battery pack 16, the power component 118 (HVH), and the radiator (not shown). The temperature control unit 120 includes, but is not particularly limited, valves, pumps, temperature sensors, etc. The temperature control unit 120 is positioned above the front drive unit 18. The temperature control unit 120 is positioned in front of the power component 118. The temperature control unit 120 and the steering gear unit 76 are positioned to overlap in the vertical direction of the vehicle. The temperature control unit 120 is positioned inward in the vehicle width direction from the steering shaft 80. This configuration makes it possible to reduce the size of the space required to house the steering shaft 80 and the temperature control unit 120.

[0055] In this embodiment, the electric vehicle 10 is left-hand drive. However, the electric vehicle 10 may also be right-hand drive. In this case, the steering shaft 80 extends from the right side in the vehicle width direction of the steering gear unit 76 toward the rear of the vehicle. In this regard, a second mount 110b is attached to the right side surface 32b in the vehicle width direction of the housing 32 of the front drive unit 18. As mentioned above, the first mount 110a and the second mount 110b are arranged symmetrically to each other. Therefore, whether the electric vehicle 10 is right-hand drive or left-hand drive, the front drive unit 18 can be positioned closer to the steering gear unit 76.

[0056] In another embodiment, the electric vehicle 10 may not include a steering shaft 80 including an intermediate shaft 82. In this case, the steering wheel 78 and the steering gear unit 76 may be connected communicatively, and the rotational operation of the steering wheel 78 by the user may be electrically transmitted to the steering gear unit 76. That is, a steer-by-wire system may be employed in the electric vehicle 10. In this case, a part of the steering gear unit 76 (for example, a part of the second casing 84b housing the rack shaft 88) may be positioned above the third mount 110c.

[0057] In this embodiment, the front drive unit 18 and the rear drive unit 20 have a common structure. However, the front drive unit 18 and the rear drive unit 20 do not necessarily have a common structure. That is, in other embodiments, the rear drive unit 20 may have a different structure from the front drive unit 18, insofar as it drives a pair of rear wheels 14r.

[0058] In this embodiment, the electric vehicle 10 includes a front drive unit 18 and a rear drive unit 20. However, the electric vehicle 10 does not necessarily need to include a rear drive unit 20. That is, in other embodiments, the electric vehicle 10 may include only a front drive unit 18.

[0059] Although several specific examples have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or in the drawings exhibit technical usefulness individually or in combination. [Explanation of Symbols]

[0060] 10: Electric vehicle, 12: Body, 14f, 14r: Wheels, 16: Battery pack, 18: Front drive unit, 20: Rear drive unit, 22, 24: Front drive shaft, 26: Motor, 28: Gear mechanism, 30: Electrical unit, 32: Housing, 76: Steering gear unit, 78: Steering wheel, 80: Steering shaft, 82: Intermediate shaft, 84: Casing, 86: Pinion shaft, 88: Rack shaft, 90: Motor, 92: Transmission mechanism, 110a, 110b, 110c: Mount, 118: Power components, 120: Temperature control unit

Claims

1. It is an electric vehicle, The car body and, Supported by the aforementioned vehicle body, it has multiple wheels including a pair of front wheels, A drive unit having a motor for driving the pair of front wheels, a differential gear mechanism for distributing the torque output by the motor to the pair of front wheels, and a housing for housing the motor and the differential gear mechanism, A steering gear unit is positioned in front of the vehicle relative to the drive unit and extends along the vehicle width direction, and steers the pair of front wheels, A steering shaft extends from the steering gear unit toward the rear of the vehicle and transmits steering operations by the user to the steering gear unit, Multiple mounts supporting the drive unit on the vehicle body, Equipped with, The plurality of mounts include a first mount attached to one side of the housing in the vehicle width direction, A portion of the steering shaft is positioned above the first mount. Electric vehicle.

2. The housing further comprises a drive shaft extending from one side of the housing in the vehicle width direction toward one of the pair of front wheels, The electric vehicle according to claim 1, wherein the first mount is located rearward of the vehicle than the drive shaft.

3. The electric vehicle according to claim 1, wherein the motor in the drive unit is arranged coaxially with the differential gear mechanism.

4. Equipped with additional power components, The electric vehicle according to claim 1, wherein the power components are located inward in the vehicle width direction from the steering shaft.

5. The electric vehicle according to claim 4, wherein the power component is a high-voltage component that constitutes part of an air conditioning system.

6. The electric vehicle is further equipped with a temperature control unit that is connected to the components via piping and through which a heat transfer medium circulates between the components, The electric vehicle according to claim 1, wherein the temperature control unit is positioned inward in the vehicle width direction from the steering shaft.

7. The electric vehicle according to claim 1, wherein the plurality of mounts further include a second mount attached to the other side of the housing in the vehicle width direction, and a third mount provided in front of the vehicle than the first mount and the second mount.

8. The electric vehicle according to claim 7, wherein a part of the steering gear unit is positioned above the third mount.

9. The steering gear unit is, A rack shaft is supported so as to be slidable along the vehicle width direction, A casing for housing the rack shaft, Equipped with, The electric vehicle according to claim 8, wherein a part of the casing is positioned above the third mount.

10. It is an electric vehicle, The car body and, Supported by the aforementioned vehicle body, it has multiple wheels including a pair of front wheels, A drive unit having a motor for driving the pair of front wheels, a differential gear mechanism for distributing the torque output by the motor to the pair of front wheels, and a housing for housing the motor and the differential gear mechanism, A steering gear unit is positioned in front of the vehicle relative to the drive unit and extends along the vehicle width direction, and steers the pair of front wheels, Multiple mounts supporting the drive unit on the vehicle body, Equipped with, The plurality of mounts include a third mount attached to the front of the housing in the vehicle longitudinal direction, An electric vehicle in which a part of the steering gear unit is positioned above the third mount.

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