Electric vehicle

Description

1 / 24 ELECTRIC VEHICLE CROSS-REFERENCE TO RELATED ORDERS

[001] This application claims priority over Japanese Patent Application No. 2024-217603, filed on December 12, 2024. The full content of the priority application is incorporated herein by reference. TECHNICAL FIELD

[002] The technique disclosed here refers to an electric vehicle. PRECEDENT TECHNIQUE

[003] Japanese Patent Application Publication No. 2023122982 describes an electric vehicle. This electric vehicle includes a plurality of wheels including a pair of front wheels, a drive unit including a motor and a steering box unit located ahead of the drive unit in a longitudinal direction of the electric vehicle, extending along the width direction of the electric vehicle and configured to steer the pair of front wheels. SUMMARY

[004] Electric vehicles, such as the one described above, can achieve a reduction in the space required to house the steering box unit and the drive unit by placing the drive unit close to the steering box unit. However, if a rearward protrusion is formed on the steering box unit, this protrusion may interfere with the drive unit. In this case, it becomes difficult to place the drive unit close to the steering box unit.

[005] In view of the foregoing, the invention in the present document provides a technology for arranging a drive unit close to a steering box unit.

[006] The technology disclosed here is incorporated into a vehicle Petition 870250105557, dated 11 / 18 / 2025, page 10 / 77 2 / 24 electric. In a first aspect, an electric vehicle may comprise a plurality of wheels comprising a pair of front wheels; a drive unit comprising a motor configured to drive the pair of front wheels and a housing housing the motor therein; and a steering box unit located ahead of the drive unit in the longitudinal direction of the electric vehicle, extending along a width direction of the electric vehicle, and configured to steer the pair of front wheels. A front surface of an end portion of the housing in the width direction may comprise a first surface inclined outwards in the width direction towards a rear portion of the electric vehicle. The steering box unit may comprise a first projection facing the first inclined surface of the housing, both on a front side in the longitudinal direction and an outward side in the width direction. BRIEF DESCRIPTION OF THE DRAWINGS

[007] Figure 1 is a diagram that schematically illustrates a configuration of an electric vehicle 10 according to one embodiment.

[008] Figure 2 is a diagram that illustrates a schematic diagram of a front drive unit 18.

[009] Figure 3 is a plan view illustrating a positional relationship between the front drive unit 18 and a steering box unit 76.

[0010] Figure 4 is a side view illustrating the positional relationship between the front drive unit 18 and the steering box unit 76.

[0011] Figure 5 is a front view illustrating the positional relationship between the front drive unit 18 and the steering box unit 76. Petition 870250105557, dated 11 / 18 / 2025, page 11 / 77 3 / 24

[0012] Figure 6 is an enlarged view of a housing 32 of the front drive unit 18.

[0013] Figure 7 is a diagram that schematically illustrates a configuration of the steering box unit 76 with an intermediate shaft 82. DETAILED DESCRIPTION

[0014] The technology disclosed herein is incorporated in an electric vehicle. In a first aspect, an electric vehicle may comprise a plurality of wheels comprising a pair of front wheels; a drive unit comprising a motor configured to drive the pair of front wheels and a housing housing the motor therein; and a steering box unit located ahead of the drive unit in the longitudinal direction of the electric vehicle, extending along a width direction of the electric vehicle, and configured to steer the pair of front wheels. A front surface of an end portion of the housing in the width direction may comprise a first surface sloping outward in the width direction towards a rear portion of the electric vehicle.The steering box unit may comprise a first projection facing the first inclined surface of the housing, both on a front side in the longitudinal direction and on an outside side in the width direction.

[0015] In the electric vehicle above, the front surface of the drive unit housing comprises the first inclined surface. The first inclined surface is located on an end portion of the housing in the width direction and is inclined outwards in the width direction towards the rear portion of the electric vehicle. Then, the steering box unit comprises the first protrusion corresponding to the first inclined surface of the drive unit. The first protrusion faces the pri Petition 870250105557, dated 11 / 18 / 2025, page 12 / 77 4 / 24 first inclined surface of the drive unit housing both on the front side and on the outside in the width direction. In this configuration, the first protrusion of the steering box unit overlaps the drive unit housing as seen in the longitudinal direction and also in the width direction. That is, the first inclined surface of the drive unit is inclined towards the rear portion of the electric vehicle so that it does not interfere with the first protrusion of the steering box unit. Thus, the drive unit can be located close to the steering box unit that comprises the first protrusion.

[0016] In a second aspect, according to the first aspect, the drive unit housing may comprise a housing body and a first cover attached to an end portion of the housing body in the width direction. In this case, the first inclined surface may be disposed on the first cover. In this configuration, even when the first inclined surface is located on an end portion of the housing, a motor and other components may be easily mounted on the housing body by removing the first cover from the housing body.

[0017] In a third aspect, according to the first or second aspects, the steering box unit may comprise a housing; a pinion shaft housed in the housing, supported rotationally by the housing and connected to a steering shaft; and a rack shaft housed in the housing, supported by the housing such that the rack shaft is sliding along the width direction and configured to move linearly in the axial direction of the rack shaft in response to the rotational motion of the pinion shaft. In this case, the first projection of the steering box unit may be a part of the steering box unit housing that houses the Petition 870250105557, dated 11 / 18 / 2025, page 13 / 77 5 / 24 pinion shaft. In this configuration, the part of the steering box unit housing that contains the pinion shaft may project backward.

[0018] In a fourth aspect, in accordance with any of the first to third aspects, the front surface of the other end portion of the housing in the width direction may comprise a second surface inclined outwards in the width direction towards the rear portion of the electric vehicle. In this configuration, the drive unit may be located close to the steering box unit, regardless of whether the electric vehicle is a right-hand drive vehicle or a left-hand drive vehicle.

[0019] In a fifth aspect, according to any one of the first to fourth aspects, the steering box unit may comprise a housing; a motor housed in the housing; a rack shaft housed in the housing, supported by the housing such that the rack shaft is sliding along the width direction and configured to move linearly in the axial direction of the rack shaft in response to the rotational motion of the motor; and a transmission mechanism housed in the housing and disposed between the motor and the rack shaft. In this case, the first projection of the steering box unit is a portion of the steering box unit housing that houses the transmission mechanism. In this configuration, the portion of the steering box unit housing that houses the transmission mechanism may project rearward.

[0020] In a sixth aspect, in accordance with any one of the first to fifth aspects, the front surface of the other end portion of the housing, in the width direction, may comprise a second surface inclined outwards in the width direction towards the rear portion of the electric vehicle. In this case, the steering box unit may comprise a second projection facing the second inclined surface of the housing. Petition 870250105557, dated 11 / 18 / 2025, page 14 / 77 6 / 24 both on the front side in the longitudinal direction and on an outer side in the width direction. In this configuration, the second inclined surface of the drive unit is inclined so as not to interfere with the second protrusion of the steering box unit. Thus, the drive unit can be located close to the steering box unit comprising the second protrusion. In a seventh aspect according to the sixth aspect, the housing may comprise a housing body, a first cover fixed to one end portion of the housing body in the width direction and a second cover fixed to the other end portion of the housing body in the width direction. In this case, the first inclined surface of the housing may be disposed on the first cover and the second inclined surface of the housing may be disposed on the second cover.In this configuration, even when the first inclined surface and the second inclined surface are arranged on opposite end portions of the housing, the motor and other components can be easily mounted in the housing body by removing the first and second housing body covers.

[0021] In an eighth aspect, according to the seventh aspect, the drive unit may further comprise an electrical unit configured to control the electrical power supplied to the motor. In this case, the housing may further comprise a third cover fixed to the rear surface of the first cover, to the rear surface of the housing body and to the rear surface of the second cover. The electrical unit may be located in a space defined by the first cover, the housing body, the second cover and the third cover. This configuration allows for more space to house the electrical unit compared to, for example, a configuration in which the third cover is fixed only to the rear surface of the housing body. Petition 870250105557, dated 11 / 18 / 2025, page 15 / 77 7 / 24

[0022] In a ninth aspect according to any one of the sixth to eighth aspects, the steering box unit may comprise a housing; a pinion shaft housed in the housing, rotatably supported by the housing and connected to a steering shaft; a motor housed in the housing; a rack shaft housed in the housing, supported by the housing such that the rack shaft is sliding along the width direction and configured to move linearly in the axial direction of the rack shaft in response to the rotational motion of the pinion shaft and the rotational motion of the motor; and a transmission mechanism housed in the housing and disposed between the motor and the rack shaft.In this case, the first protrusion of the steering box unit may be a part of the steering box unit housing that houses the pinion shaft, and the second protrusion of the steering box unit may be another part of the steering box unit housing that houses the transmission mechanism. In this configuration, the part of the steering box unit housing that houses the pinion shaft and the part of the same housing that houses the transmission mechanism may project backward.

[0023] Representative and non-limiting examples of the present invention will now be described in more detail with reference to the accompanying drawings. This detailed description is intended only to teach one skilled in the art more details for the practice of preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed below can be used separately or in conjunction with other features and teachings to provide improved electric vehicles, as well as methods for using and manufacturing them.

[0024] In addition, the combinations of features and steps disclosed in the detailed description below may not be necessary. Petition 870250105557, dated 11 / 18 / 2025, page 16 / 77 8 / 24 rias to practice the invention in the broadest sense, being taught only to describe specific representative examples of the invention. Furthermore, various features of the representative examples described above and described below, as well as the various independent and dependent claims, can be combined in ways that are not specifically and explicitly enumerated, in order to provide additional useful embodiments of the present teachings.

[0025] All features disclosed in the description and / or claims are intended to be disclosed separately and independently of each other for purposes of original written invention, as well as for purposes of restricting the claimed subject matter, regardless of the compositions of the features in the embodiments and / or claims. Furthermore, all ranges of values ​​or indications of groups of entities are intended to disclose all possible intermediate values ​​or intermediate entities for purposes of original written invention, as well as for purposes of restricting the claimed subject matter.

[0026] Referring to the drawings, an electric vehicle 10 according to an embodiment is described. The electric vehicle 10 is called a car. The electric vehicle 10 moves on road surfaces. The electric vehicle 10 is not limited to a user-driven / operated vehicle and may be a remotely operated vehicle by an external device or an autonomous vehicle.

[0027] In the drawings, a direction FR corresponds to the front direction of the longitudinal direction (or front-to-rear direction) of the electric vehicle 10 (which may be referred to as the “longitudinal direction of the vehicle”), and a direction RR corresponds to the rear direction of the longitudinal direction of the electric vehicle 10. A direction LH corresponds to the left direction of the width direction (or right-to-left direction) of the electric vehicle 10 (which may be referred to as the “width direction of the vehicle”), and a direction RH corresponds to the right direction of the width direction. Petition 870250105557, dated 11 / 18 / 2025, p. 17 / 77 9 / 24 figure of the electric vehicle 10. An UP direction corresponds to the upward direction of the height direction (or top-down direction) of the electric vehicle 10 (which may be referred to as the “vehicle height direction”), and a DW direction corresponds to the downward direction of the height direction of the electric vehicle 10.

[0028] As illustrated in Figure 1, the electric vehicle 10 comprises a vehicle body 12 and a plurality of wheels 14f, 14r. The vehicle body 12 comprises a cabin 12c which is a passenger space. The plurality of wheels 14f, 14r is supported by the vehicle body 12. The plurality of wheels 14f, 14r is rotatably attached to the vehicle body 12. The plurality of wheels 14f, 14r includes a pair of front wheels 14f located on a front portion of the vehicle body 12 and a pair of rear wheels 14r located on a rear portion of the vehicle body 12. The front wheels 14f are coaxial with each other and the rear wheels 14r are also coaxial with each other. The number of wheels 14f, 14r is not limited to four. Furthermore, the body of vehicle 12 is made of a metal, such as steel or aluminum alloy, although this is just one example.

[0029] As illustrated in Figure 1, the electric vehicle 10 further comprises a battery pack 16, a front drive unit 18 and a rear drive unit 20. The battery pack 16 comprises, for example, a plurality of secondary battery cells and is repeatedly rechargeable with external electrical power. The battery pack 16 supplies electrical power to each of the front drive units 18 and the rear drive unit 20. The battery pack 16 is located below the cabin 12c. The front drive unit 18 is located in the front portion of the vehicle body 12. The rear drive unit 20 is located in the rear portion of the vehicle body 12. Petition 870250105557, dated 11 / 18 / 2025, page 18 / 77 10 / 24

[0030] The front drive unit 18 drives the pair of front wheels 14f. The rear drive unit 20 drives the pair of rear wheels 14r. The front drive unit 18 and the rear drive unit 20 have the same configuration, except for the difference in the wheels that drive them. For this reason, only the configuration of the front drive unit 18 is described below, and the description of the configuration of the rear drive unit 20 is omitted.

[0031] As illustrated in Figures 2 to 4, 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 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.

[0032] As illustrated in Figures 2 and 3, the front drive unit 18 comprises a motor 26, a gear mechanism 28, an electrical unit 30, the housing 32, a left output shaft 34 and a right output shaft 36. The motor 26 is a traction motor for driving the pair of front wheels 14f. In this embodiment, the motor 26 is a three-phase AC power-driven motor. The gear mechanism 28 distributes the drive power of the motor 26 to the pair of front wheels 14f. The motor 26 is connected to each of the left output shaft 34 and the right output shaft 36 by means of the gear mechanism 28. The left output shaft is Petition 870250105557, dated 11 / 18 / 2025, page 19 / 77 11 / 24 left 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. Thus, the motor 26 is connected to the pair of front wheels 14f via the gear mechanism 28, the output shafts 34, 36, and the front drive shafts 22, 24. Therefore, the motor 26 can drive the pair of front wheels 14f. In this embodiment, the motor 26 is coaxial with the gear mechanism 28.

[0033] Electrical unit 30 controls the electrical power supplied to motor 26. In this embodiment, electrical unit 30 comprises an inverter and controls the electrical power supplied between the battery pack 16 and the motor 26. Electrical unit 30 is located behind the motor 26 and the gear mechanism 28. Electrical unit 30 may also comprise a DC-DC converter.

[0034] As illustrated in Figures 2 to 6, the housing 32 is a closing element. The housing 32 houses the motor 26, the gear mechanism 28, and the electrical unit 30 within it. The housing 32 comprises a housing body 38, a first cover 40, a second cover 42, and a third cover 44. The housing body 38 includes a first opening 38a and a second opening 38b. The first opening 38a is formed on an end surface 38c of the housing body 38 in the width direction of the vehicle (i.e., a left end surface 38c). The second opening 38b is formed on the other end surface 38d of the housing body 38 in the width direction of the vehicle (i.e., a right end surface 38d). Thus, the internal space of the housing body 38 is in communication with the external space of the housing body 38 at each of the left end surfaces 38c and the right end surfaces 38d.The first cover 40 is attached to the left end surface. Petition 870250105557, dated 11 / 18 / 2025, page 20 / 77 12 / 24 38c of the housing body 38 and closes the first opening 38a. The second cover 42 is fixed to the right end surface 38d of the housing body 38 and closes the second opening 38b. The motor 26 and the gear mechanism 28 are located in a space S1 defined by the first cover 40, the housing body 38 and the second cover 42.

[0035] The third cover 44 is attached to a rear surface. 40a of the first cover 40, to a rear surface 38e of the housing body 38 and to a rear surface 42a of the second cover 42. The electrical unit 30 is located in a space S2 defined by the first cover 40, the housing body 38, the second cover 42 and the third cover 44.

[0036] As illustrated in Figure 2, the motor 26 comprises a rotor 46, a stator 48, and a rotor shaft 50. The rotor 46 is supported against the housing 32 so that it can rotate around a rotation axis R1. The stator 48 has a substantially tubular shape, having the rotation axis R1 as its central axis. The stator 48 is fixed to an 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 integrally with the rotor 46. The rotor shaft 50 comprises a through hole 50a extending in the direction of the rotation axis R1. The right output shaft 36 is located inside the through hole 50a.

[0037] As illustrated in Figure 2, the gear mechanism 28 comprises a planetary gear mechanism 52 and a differential gear mechanism 54. The planetary gear mechanism 52 reduces the rotational speed of the rotor shaft 50 of the motor 26. The differential gear mechanism 54 distributes the torque of the motor 26 transmitted through the planetary gear mechanism 52 to the pair of front wheels 14f. In this Petition 870250105557, dated 11 / 18 / 2025, page 21 / 77 In mode 13 / 24, the differential gear mechanism 54 is coaxial with the motor 26.

[0038] As illustrated in Figure 2, 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 integrally with the rotor shaft 50. Each of the 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 gears 58b is smaller than the diameter of the large-diameter pinion gears 58a. The large-diameter pinion gears 58a mesh with the sun gear 56. The small-diameter pinion gears 58b mesh with the ring gear 60.Each of the stepped pinion gears 58 meshes with the sun gear 56 and with the ring gear 60, so that they can rotate around their own axes of rotation and orbit around the sun gear 56. The ring gear 60 is fixed to the housing 32. The loader 62 supports the plurality of stepped pinion gears 58 so that they can rotate. Furthermore, the loader 62 is supported against the housing 32 so that it can rotate around the axis of rotation R1. Thus, the rotation of the plurality of stepped pinion gears 58 causes the loader 62 to rotate around the axis of rotation R1.

[0039] As illustrated in Figure 2, the differential gear mechanism 54 comprises a differential housing 64, a pinion shaft 66, differential pinion gears 68, 70, a left side gear 72 and a right side gear 74. The differential housing 64 is supported against the housing 32 in such a way Petition 870250105557, dated 11 / 18 / 2025, page 22 / 77 14 / 24 that can rotate around the axis of rotation R1. The differential housing 64 is connected to the loader 62 of the planetary gear mechanism 52 and rotates integrally with the loader 62. The pinion shaft 66, the differential pinion gears 68, 70, the left side gear 72 and the right side gear 74 are housed in the differential housing 64.

[0040] The pinion shaft 66 is connected to the differential housing 64 and rotates integrally with the differential housing 64. The pinion shaft 66 extends in a direction perpendicular to the direction of the axis of rotation R1. The differential pinion gears 68, 70 are supported against the pinion shaft 66 so that they can rotate around the axis of the pinion shaft 66. The left side gear 72 and the right side gear 74 are coaxial with each other and are positioned opposite each other. The left side gear 72 engages with each of the differential pinion gears 68, 70. The left side gear 72 is connected to the left output shaft 34. The right side gear 74 engages with each of the differential pinion gears 68, 70. The right side gear 74 is connected to the right output shaft 36.

[0041] In this document, a power transmission flow in the front drive unit 18 described above is described. The rotary power of the rotor shaft 50 of the motor 26 is transmitted to the stepped pinion gears 58 through the rotation of the sun gear 56. The stepped pinion gears 58, once the power is transmitted to them, rotate along the inner circumference of the ring gear 60 under a reaction force from the fixed ring gear 60 while rotating around their own axes of rotation. The rotary motion of the stepped pinion gears 58 is transmitted as the rotation of the loader 62. In the differential housing 64, which rotates integrally with the loader Petition 870250105557, dated 11 / 18 / 2025, page 23 / 77 15 / 24 62, power is transmitted from the differential pinion gears 68, 70 to the side gears 72, 74. The front drive shafts 22, 24 are rotated by the power transmitted to the side gears 72, 74. As described above, in this embodiment, among the components of the front drive unit 18, the sun gear 56 functions as an input element, the ring gear 60 functions as a reaction element, and the loader 62 functions as an output element.

[0042] In addition to the motor 26, each of the front drive unit 18 and the rear drive unit 20 may also comprise another drive source, such as a motor. Furthermore, in addition to or instead of the battery pack 16, the electric vehicle 10 may comprise another energy source, such as a fuel cell unit or a solar panel. Thus, the electric vehicle 10 is not limited to a battery-powered electric vehicle and may be another type of electric vehicle, such as a hybrid vehicle, a fuel cell vehicle, or a solar-powered car.

[0043] As illustrated in Figure 1, the electric vehicle 10 comprises a steering box unit 76, a steering wheel 78, and a steering shaft 80, including an intermediate shaft 82. The steering box unit 76 steers the pair of front wheels 14f. The steering box unit 76 is located in front of the front drive unit 18 and extends in the width direction of the vehicle. The steering wheel 78 is located in front of the driver's seat and is operated by the user. The steering shaft 80 transmits the user's steering action to the steering box unit 76. The steering shaft 80 extends rearward from the steering box unit 76. As the electric vehicle 10 according to this embodiment is a left-hand drive vehicle, the steering shaft 80 extends rearward from a left portion of the steering box unit 76. The extremi Petition 870250105557, dated 11 / 18 / 2025, page 24 / 77 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 box unit 76. Thus, the steering shaft 80 can transmit the user's steering action, which is the rotation of the steering wheel 78, to the steering box unit 76. In another embodiment, the steering shaft 80 may not include the intermediate shaft 82 and may consist of a single shaft.

[0044] As illustrated in Figures 3 to 5 and 7, the steering box unit 76 comprises a housing 84, a pinion shaft 86, a rack shaft 88, a motor 90 and a transmission mechanism 92. The housing 84 comprises a first housing 84a, a second housing 84b, a third housing 84c and a fourth housing 84d. The housing 84 may consist of a single housing element or multiple housing elements.

[0045] The pinion shaft 86 is housed in the first housing 84a and is rotationally supported by the first housing 84a. The pinion shaft 86 is connected to the steering shaft 80. In this embodiment, a rear end portion of the pinion shaft 86 is connected to the front end portion of the steering shaft 80. Thus, the pinion shaft 86 can rotate in response to the user's steering action on the steering wheel 78. A pinion gear portion 86a is formed on the outer surface of a front end portion of the pinion shaft 86. The rack shaft 88 is housed in the second housing 84b and supported by the second housing 84b so that the rack shaft 88 is sliding in the width direction of the vehicle. A rack gear portion 88a is formed on the outer surface of the rack shaft 88. The rack gear portion 88a engages with the pinion gear portion 86a.Thus, the rack shaft 88 can move linearly in the axial direction of the rack shaft 88 in response to rotational motion. Petition 870250105557, dated 11 / 18 / 2025, p. 25 / 77 17 / 24 of the pinion shaft 86. The linear motion of the rack shaft 88 is transmitted to the pair of front wheels 14f. In this way, the linear motion of the rack shaft 88 causes the pair of front wheels 14f to change direction. The steering rods and steering joints may be located between the rack shaft 88 and the front wheels 14f.

[0046] The motor 90 is a drive source for the rack and pinion shaft 88. In this embodiment, the motor 90 is driven by three-phase AC power. A rotating shaft R2 of the motor 90 extends parallel to the rack and pinion shaft 88. The motor 90 is controlled by a control unit (not shown). The motor 90 can assist the steering action by a user on the steering wheel 78, moving the rack and pinion shaft 88. If the electric vehicle 10 can move autonomously, the rack and pinion shaft 88 can be moved without the need for steering action by a user on the steering wheel 78. The motor 90 is housed in the third housing 84c.

[0047] The transmission mechanism 92 is interposed between the motor and the rack shaft 88. The transmission mechanism 92 is configured to convert the rotational motion of the motor 90 into the linear motion of the rack shaft 88. That is, the rotation of the motor 90 causes the rack shaft 88 to move along the axial direction. The configuration of the transmission mechanism 92 is not particularly limited. In this embodiment, the transmission mechanism 92 comprises a belt mechanism 94 and a linear motion mechanism 96, although this is only one example. 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 received rotational motion through the Petition 870250105557, dated 11 / 18 / 2025, page 26 / 77 18 / 24 belt mechanism 94 in the linear motion of the rack shaft 88. The belt mechanism 94 and the linear motion mechanism 96 are housed in the fourth housing 84d.

[0048] As illustrated in Figure 7, the belt mechanism 94 comprises a pair of pulleys 98, 100 and a belt 102. The belt 102 is placed around 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 the motor 90 and is driven by the motor 90. The driven pulley 100 is coaxial with the rack shaft 88. The diameter of the driven pulley 100 is larger than the diameter of the drive pulley 98, although this is not always the case. Thus, the belt mechanism 94 also functions as a speed reduction mechanism.

[0049] As illustrated in Figure 7, 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 positioned to enclose the rack shaft 88. The driven pulley 100 is fixed coaxially to the ball nut 104. Thus, the ball nut 104 rotates together with the rotation of the driven pulley 100. A groove 104a is defined on the inner surface of the ball nut 104. A groove 88b is defined on the outer surface of the rack shaft 88. The ball plurality 106 is located between the groove 104a of the ball nut 104 and the groove 88b of the rack shaft 88. In this way, the ball nut 104 and the rack shaft 88 are threaded together by means of the ball plurality 106. The ball nut 104 is rotationally supported by the bearing 108 against the fourth housing 84d.

[0050] In the transmission mechanism 92 described above, the drive pulley 98 rotates when the motor 90 rotates. The rotation of the pulley of Petition 870250105557, dated 11 / 18 / 2025, page 27 / 77 19 / 24 drive 98 is transmitted to the driven pulley 100 via belt 102, causing the driven pulley 100 and the ball nut 104 to rotate. Since the diameter of the driven pulley 100 is greater than the diameter of the drive pulley 98 in this embodiment, the rotational speed of the driven pulley 100 and the ball nut 104 is less 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 varies depending on the ratio between the diameter of the drive pulley 98 and the diameter of the driven pulley 100. As the ball nut 104 rotates relatively relative to the rack shaft 88, the plurality of balls 106 interposed between the ball nut 104 and the rack shaft 88 is subjected to the loads of the ball nut 104 and the rack shaft 88 and circulates continuously in a bearing passage A.The continuous circulation of the balls 106 converts the torque applied to the ball nut 104 into a force applied in the axial direction of the rack shaft 88. Thus, the rack shaft 88 moves linearly in the axial direction of the rack shaft 88 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 acts as an auxiliary force to help the pair of front wheels 14f change direction.

[0051] As illustrated in Figures 3 to 5, the steering box unit 76 comprises a first projection 77a. The first projection 77a consists mainly of the first housing 84a and the pinion shaft 86 is housed therein, although this is only an example. As illustrated in Figures 3 to 6, a front surface 33 of the housing 32 of the front drive unit 18 comprises a first inclined surface 33a. The first inclined surface 33a is located on an end portion of the Petition 870250105557, dated 11 / 18 / 2025, page 28 / 77 20 / 24 housing 32 in the width direction of the vehicle (i.e., a left-hand end portion) and is inclined outwards in the width direction of the vehicle towards the rear portion of the electric vehicle. The first protrusion 77a is located corresponding to the first inclined surface 33a of the front drive unit 18. Specifically, the first protrusion 77a faces the first inclined surface 33a of housing 32 of the front drive unit 18, both from the front side in the longitudinal direction of the vehicle and from the outside side in the width direction of the vehicle.

[0052] In the configuration above, the first protrusion 77a of the steering box unit 76 overlaps the housing 32 of the front drive unit 18 as seen in the longitudinal direction of the vehicle and also in the width direction of the vehicle. That is, the first inclined surface 33a of the front drive unit 18 is inclined towards the rear portion of the electric vehicle, so that it does not interfere with the first protrusion 77a of the steering box unit 76. Thus, the front drive unit 18 can be arranged close to the steering box unit 76, including the first protrusion 77a.

[0053] The first protrusion 77a of the steering box unit 76 is not limited to a specific part of a component. As described, in this embodiment, the first protrusion 77a is a part of the housing 84 of the steering box unit 76 and the pinion shaft 86 is housed therein. In this configuration, the part of the housing 84 of the steering box unit 76 that houses the pinion shaft 86 may project backward. Generally, the pinion shaft 86 usually projects backward in the steering box unit 76. Thus, in the above configuration, the pinion shaft 86 may project backward.

[0054] As illustrated in Figures 3 and 5, the steering box unit 76 comprises a second protrusion 77b. The second sa Petition 870250105557, dated 11 / 18 / 2025, page 29 / 77 21 / 24 protrusion 77b is mainly comprised of the fourth housing 84d and the transmission mechanism 92 is housed therein, although this is only one example. As illustrated in Figures 3 to 6, the front surface 33 of the housing 32 of the front drive unit 18 comprises a second inclined surface 33b. The second inclined surface 33b is located on the other end portion of the housing 32 in the width direction of the vehicle (i.e., a right end portion) and is inclined outwards in the width direction of the vehicle towards the rear portion of the electric vehicle. The second protrusion 77b is located corresponding to the second inclined surface 33b of the front drive unit 18.Specifically, the second protrusion 77b faces the second inclined surface 33b of the housing 32 of the front drive unit 18, both from the front side in the longitudinal direction of the vehicle and from the outside side in the width direction of the vehicle.

[0055] The second projection 77b of the steering box unit 76 overlaps the housing 32 of the front drive unit 18 as seen in the longitudinal direction of the vehicle and also as seen in the width direction of the vehicle. That is, the second inclined surface 33b of the front drive unit 18 is inclined backward so as not to interfere with the second projection 77b of the steering box unit 76. Thus, the front drive unit 18 can be positioned close to the steering box unit 76 which comprises the second projection 77b.

[0056] The second protrusion 77b of the steering box unit 76 is not limited to a specific part of a component. As described, in this embodiment, the second protrusion 77b is a part of the housing 84 of the steering box unit 76 and the transmission mechanism 92 is housed therein. In this configuration, the part of the housing 84 of the steering box unit 76 that houses the transmission mechanism is housed therein. Petition 870250105557, dated 11 / 18 / 2025, page 30 / 77 22 / 24 transmission system 92 may project backward.

[0057] In the above embodiment, the steering box unit 76 comprises the first protrusion 77a and the second protrusion 77b, while the front surface 33 of the housing 32 of the front drive unit 18 comprises the first inclined surface 33a facing the first protrusion 77a and the second inclined surface 33b facing the second protrusion 77b. In this configuration, the part of the housing 84 of the steering box unit 76 that houses the pinion shaft 86 and the part thereof that houses the transmission mechanism 92 may project rearward.

[0058] However, the steering box unit 76 does not necessarily comprise either the first protrusion 77a or the second protrusion 77b. In another embodiment, the steering box unit 76 may comprise only one of the first protrusion 77a and the second protrusion 77b. In other words, the steering box unit 76 may comprise only one of the pinion shaft 86 and the transmission mechanism 92.

[0059] Even in the case where the steering box unit 76 comprises only the first protrusion 77a housing the pinion shaft 86, the front surface 33 of the housing 32 of the front drive unit 18 may comprise both the first inclined surface 33a and the second inclined surface 33b. In this configuration, the front drive unit 18 may be disposed close to the steering box unit 76, regardless of whether the electric vehicle 10 is a right-hand drive vehicle or a left-hand drive vehicle.

[0060] However, the front surface 33 of the housing 32 of the front drive unit 18 does not necessarily comprise either the first inclined surface 33a or the second inclined surface 33b. In another embodiment, the front surface 33 of Petition 870250105557, dated 11 / 18 / 2025, page 31 / 77 23 / 24 housing 32 of the front drive unit 18 may comprise only one of the first inclined surface 33a and the second inclined surface 33b. In this case, the inclined surface of the front drive unit 18 may face a protrusion of the steering box unit 76.

[0061] In the above embodiment, the first inclined surface 33a of the housing 32 is disposed in the first cover 40. In this configuration, even though the first inclined surface 33a is located in the end portion of the housing 32, the internal space of the housing body 38 is opened to the outside through the first opening 38a (see Figure 6) when the first cover 40 is removed from the housing body 38. Thus, the motor 26 and other components can be easily mounted in the housing body 38.

[0062] In addition to the above, in the above embodiment, the second inclined surface 33b of the housing 32 is disposed in the second cover 42. In this configuration, even when the first inclined surface 33a and the second inclined surface 33b are located on opposite end portions of the housing 32, the internal space of the housing body 38 is opened to the outside through the first opening 38a and the second opening 38b (see Figure 6) by removing the first cover 40 and the second cover 42 from the housing body 38. Thus, the motor 26 and other components can be easily mounted in the housing body 38.

[0063] In the embodiment above, the front drive unit and the rear drive unit 20 have the same structure. However, the front drive unit 18 and the rear drive unit 20 do not necessarily have the same structure. That is, in another embodiment, the rear drive unit 20 may have any structure different from the front drive unit 18, provided that it can drive the pair of rear wheels 14r. Petition 870250105557, dated 11 / 18 / 2025, page 32 / 77 24 / 24

[0064] In the embodiment above, the electric vehicle 10 comprises the front drive unit 18 and the rear drive unit 20. However, the electric vehicle 10 does not necessarily comprise the rear drive unit 20. That is, in another embodiment, the electric vehicle 10 may comprise only the front drive unit 18. Petition 870250105557, dated 11 / 18 / 2025, page 33 / 77

Claims

1 / 4 CLAIMS 1. Electric vehicle (10), characterized in that it comprises: a plurality of wheels (14f, 14r) comprising a pair of front wheels (14f); a drive unit (18) comprising a motor (26) configured to drive the pair of front wheels (14f) and a housing (32) housing the motor (26) therein;and a steering box unit (76) located ahead of the drive unit (18) in the longitudinal direction of the electric vehicle (10), extending along a width direction of the electric vehicle (10) and configured to steer the pair of front wheels (14f), wherein a front surface (33) of an end portion of the housing (32) in the width direction comprises a first inclined surface (33a) inclined outwards in the width direction towards a rear portion of the electric vehicle (10), and the steering box unit (76) comprises a first projection (77a) facing the first inclined surface (33a) of the housing (32) both from a front side in the longitudinal direction and from an outside side in the width direction.

2. Electric vehicle, according to claim 1, characterized in that the housing (32) comprises a housing body (38) and a first cover (40) fixed to an end portion of the housing body (38) in the width direction, and the first inclined surface (33a) is disposed on the first cover (40).

3. Electric vehicle, according to claim 1 or 2, Petition 870250105557, dated 11 / 18 / 2025, page 34 / 77 2 / 4 characterized in that the steering box unit (76) comprises: a housing (84); a pinion shaft (86) housed in the housing (84), rotatably supported by the housing (84) and connected to a steering shaft (80); and a rack shaft (88) housed in the housing (84), supported by the housing (84) so ​​that the rack shaft (88) is sliding along the width direction, and configured to move linearly in the axial direction of the rack shaft (88) in response to the rotational motion of the pinion shaft (86), and the first projection (77a) of the steering box unit (76) is a part of the housing (84) of the steering box unit (76) that houses the pinion shaft (86).

4. Electric vehicle, according to any one of claims 1 to 3, characterized in that the front surface (33) of the other end portion of the housing (32) in the width direction comprises a second inclined surface (33b) inclined outwards in the width direction towards the rear portion of the electric vehicle (10).

5. Electric vehicle, according to any one of claims 1 to 4, characterized in that the steering box unit (76) comprises: a housing (84); a motor (90) housed in the housing (84); a rack shaft (88) housed in the housing (84), supported by the housing (84) such that the rack shaft (88) is sliding along the width direction and configured to move linearly in the axial direction of the rack shaft (88) in response to the rotational motion of the motor (90); and Petition 870250105557, dated 11 / 18 / 2025, p. 35 / 77 3 / 4 a transmission mechanism (92) housed in the housing (84) and disposed between the motor (90) and the rack shaft (88), and the first projection (77a) of the steering box unit (76) is a part of the housing (84) of the steering box unit (76) that houses the transmission mechanism (92).

6. Electric vehicle, according to any one of claims 1 to 5, characterized in that the front surface (33) of the other end portion of the housing (32) in the width direction comprises a second inclined surface (33b) inclined outwards in the width direction towards the rear portion of the electric vehicle (10), and the steering box unit (76) comprises a second projection (77b) facing the second inclined surface (33b) of the housing (32) on both the front side in the longitudinal direction and an outer side in the width direction.

7. Electric vehicle, according to claim 6, characterized in that the housing (32) comprises a housing body (38), a first cover (40) fixed to one end portion of the housing body (38) in the width direction and a second cover (42) fixed to the other end portion of the housing body (38) in the width direction, the first inclined surface (33a) of the housing (32) is disposed on the first cover (40), and the second inclined surface (33b) of the housing (32) is disposed on the second cover (42).

8. Electric vehicle, according to claim 7, characterized in that the drive unit (18) further comprises an electrical unit (30) configured to control the electrical energy supplied to the motor (26), the housing (32) further comprises a third cover (44) fixed to a rear surface (40a) of the first cover (40), a rear surface (38e) of the housing body (38) and a rear surface (42a) of the second cover (42), and the electrical unit (30) is located in a space (S2) defined by the first cover (40), the housing body (38), the second cover (42) and the third cover (44).

9. Electric vehicle, according to any one of claims 6 to 8, characterized in that the steering box unit (76) comprises: a housing (84); a pinion shaft (86) housed in the housing (84), rotatably supported by the housing (84) and connected to a steering shaft (80); a motor (90) housed in the housing (84); a rack shaft (88) housed in the housing (84), supported by the housing (84) such that the rack shaft (88) is sliding along the width direction, and configured to move linearly in the axial direction of the rack shaft (88) in response to the rotational motion of the pinion shaft (86) and the rotational motion of the motor (90);and a transmission mechanism (92) housed in the housing (84) and disposed between the motor (90) and the rack shaft (88), the first projection (77a) of the steering box unit (76) is a part of the housing (84) of the steering box unit (76) that houses the pinion shaft (86), and the second projection (77b) of the steering box unit (76) is another part of the housing (84) of the steering box unit (76) that houses the transmission mechanism (92). Petition 870250105557, dated 11 / 18 / 2025, page 37 / 77;

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