Vehicular in-wheel motor drive unit

Abstract

To provide a vehicular in-wheel motor drive unit improving replaceability of a stepped pinion.SOLUTION: An in-wheel motor drive unit 10 includes a wheel 14 mounted on an outer side in a vehicle width direction (and a mounted tire 12) and a cover 16. A stepped pinion 34 is disposed at a position where an end face of a large diameter gear 34a of the stepped pinion 34 faces the cover 16. When the wheel 14 (and the mounted tire 12) and the cover 16 are removed, the stepped pinion 34 becomes detachable. Accordingly, replaceability of the stepped pinion 34 can be improved.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an in-wheel motor drive unit provided in an electric vehicle. [Background technology]

[0002] In-wheel motor drive units, which are installed inside the wheels of electric vehicles, are known. To reduce the size of the motor, some in-wheel motor drive units have been disclosed that use a stepped pinion in a planetary gear unit, which allows for a larger reduction ratio of the motor. For example, Patent Document 1 discloses such a drive unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-8248 Summary of the Invention [Problem to be solved by the invention]

[0004] In in-wheel motor drive units that use stepped pinions, the ease of maintenance of the stepped pinions is important. If the stepped pinion is located away from a removable cover or on the opposite side of the cover, or if the cover cannot be removed, when the stepped pinion needs to be replaced, it becomes difficult to remove the surrounding parts and the entire unit must be disassembled. As a result, replacing the stepped pinion and completing its assembly requires a considerable amount of man-hours and time, resulting in issues such as high maintenance costs for the drive unit.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide an in-wheel motor drive unit for a vehicle that improves the replaceability of a stepped pinion. [Means for solving the problem]

[0006] The gist of the present invention is (a) an in-wheel motor drive unit for a vehicle equipped with a reduction mechanism including a stepped pinion, (b) having a wheel and a cover attached to the outside in the vehicle width direction, (c) the stepped pinion is arranged in a position where the end face of the large diameter gear of the stepped pinion faces the cover, and (d) when the wheel and the cover are removed, the stepped pinion can be removed. [Effects of the Invention]

[0007] According to the present invention, the vehicle in-wheel motor drive unit has a wheel and a cover attached to the outer side in the vehicle width direction, and the stepped pinion is disposed in a position where an end face of the large diameter gear of the stepped pinion faces the cover, so that the stepped pinion can be detached when the wheel and the cover are removed, thereby improving the replaceability of the stepped pinion.

[0008] Preferably, a ring-shaped rubber seal is disposed between the cover and the carrier, which is the mounting surface of the cover. Cover fastening bolts, which apply tension to the rubber seal to fasten the cover and the carrier, are disposed outside the ring-shaped rubber seal and between each of the multiple stepped pinions. This prevents the intrusion of foreign matter, water, etc. into the interior. Furthermore, the rubber seal provides a tight seal simply by attaching the cover with the cover fastening bolts, improving maintenance workability.

[0009] Preferably, the wheel fastening bolts that fasten the three components of the wheel, the cover, and the carrier together are disposed on the outer circumferential side of the cover fastening bolts. This arrangement allows the wheel fastening bolts to be disposed on the outer circumferential side where the axial force is applied, where the diameter is larger, thereby reducing the axial force required for torque transmission and enabling a reduction in the number and size of the wheel fastening bolts. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating the configuration of a vehicle in-wheel motor drive unit to which the present invention is applied; [Figure 2] FIG. 1 is a diagram corresponding to FIG. 1 and illustrating another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0012] FIG. 1 is a diagram illustrating the configuration of a vehicle in-wheel motor drive unit (hereinafter referred to as in-wheel motor drive unit) 10 to which the present invention is applied. The in-wheel motor drive units 10 are provided on the drive wheels on both the left and right sides of a vehicle. The left and right in-wheel motor drive units 10 are symmetrical in configuration and structure and have the same functions, so FIG. 1 will explain the in-wheel motor drive unit 10 on the left side of the vehicle. FIG. 1(a) is a side view seen from the outside in the vehicle width direction, and FIG. 1(b) is a cross-sectional view of the AA axis in FIG. 1(a) seen from the rear of the vehicle. The X axis represents the direction of travel of the vehicle, the Y axis represents the vehicle width direction, and the Z axis represents the vehicle vertical direction. The rotational axis of the drive wheel is indicated as rotational axis CL.

[0013] The in-wheel motor drive unit 10 includes a tire 12, a wheel 14, a cover 16, a housing 40, a motor MG, a drive shaft 44, a brake 46, a reduction mechanism 30, and the like.

[0014] When viewed from the outside in the vehicle width direction, the wheel 14 is disposed on the outermost surface, with a cover 16 disposed behind the wheel 14 and a speed reduction mechanism 30 (described later) disposed behind the cover 16. In Fig. 1(a), each gear (described later) provided in the speed reduction mechanism 30 is indicated by a two-dot chain line. The tire 12 is mounted integrally on the outer periphery of the wheel 14.

[0015] The housing 40 is a non-rotating member that connects the in-wheel motor drive unit 10 to the vehicle body, and is fastened to the vehicle body with bolts (not shown) etc. The housing 40 also serves to house a brake 46 (described later) and as a fixing member for the motor MG.

[0016] The motor MG is an in-wheel motor that drives the drive wheels (tires 12, wheels 14). The motor MG is, for example, a three-phase motor, and is electrically connected to a power supply device mounted on the vehicle. During power running, the motor MG generates rotational force on a motor shaft 42 using power supplied from the power supply device to drive the drive wheels. During regeneration, the motor shaft 42 of the motor MG is rotated by the rotational force of the drive wheels to generate electricity, and the generated electricity is supplied to the power supply device. The motor shaft 42 of the motor MG, which is provided on the rotation axis CL, is connected to a drive shaft 44 via a joint 42a. Furthermore, the exterior case of the motor MG is integrally fastened to the housing 40 by a bolt MGb.

[0017] The drive shaft 44 is a shaft that transmits power between the motor MG and the reduction gear mechanism 30, and has one end connected to the joint 42a and the other end connected to the sun gear 32 (described later). The drive shaft 44 is supported by bearings 48 and 50 so as to be rotatable about the rotation axis CL relative to the housing 40, and the brake disc 46a is fixed to rotate integrally with the drive shaft 44.

[0018] The brake 46 is a unit that brakes the rotation of the drive shaft 44, and generates a braking force by clamping the rotation of a brake disc 46a between the brake 46 and a brake pad mechanism 46b using hydraulic control (not shown). The brake 46 brakes the rotation of the drive shaft 44, thereby braking the drive wheels (tires 12, wheels 14) connected via the reduction gear mechanism 30. The brake 46 is also fastened integrally to the housing 40 by bolts 46c.

[0019] The reduction mechanism 30 is configured as a planetary gear device and includes a sun gear 32, three stepped pinions 34, a ring gear 36, and a carrier 38.

[0020] The sun gear 32 is connected to and supported by the drive shaft 44 so as to rotate integrally with the drive shaft 44 .

[0021] The stepped pinion 34 includes a large-diameter gear 34a that meshes with the sun gear 32 and a small-diameter gear 34b that meshes with the ring gear 36. The large-diameter gear 34a and the small-diameter gear 34b rotate integrally. As shown in FIG. 1(b), the stepped pinion 34 is disposed in a position where the end face of the large-diameter gear 34a faces the cover 16, and is disposed so as to be detachable when the wheel 14 and the cover 16 are removed.

[0022] The ring gear 36 is fixed to a housing 40, which is a non-rotating member.

[0023] The carrier 38 supports the three stepped pinions 34 rotatably and revolvably, and is formed into a shape that allows the wheels 14 and the cover 16 to be fastened together and rotate integrally. The carrier 38 is supported by bearings 52 and 54 to be rotatable about the rotation axis CL relative to the housing 40.

[0024] The speed reduction mechanism 30 operates to reduce the rotation transmitted from the motor MG to the sun gear 32 via the drive shaft 44 and transmit the reduced rotation to the carrier 38. When the sun gear 32 rotates, the small diameter gear 34b rotates together with the large diameter gear 34a. However, because the small diameter gear 34b is meshed with the fixed ring gear 36, the stepped pinion 34 revolves while rotating on its axis. This operation causes the rotation of the sun gear 32 to be output to the carrier 38 as reduced rotation (revolving rotation). The carrier 38 and the wheel 14 are connected so as to be capable of transmitting power, thereby driving the drive wheels (tires 12, wheels 14).

[0025] The cover 16 and the wheel 14 (and the attached tire 12) are attached in this order to the attachment surface of the carrier 38 on the outer side in the vehicle width direction.

[0026] The cover 16 is a disk-shaped cover that shields the internal components, including the reduction gear mechanism 30, from the outside of the vehicle. The cover 16 is fastened to the mounting surface of the carrier 38 on the outer side in the vehicle width direction using cover fastening bolts 20. The cover 16 also has holes through which wheel fastening bolts 18, which will be described later, pass.

[0027] After the cover 16 is attached, the wheel 14 (and the attached tire 12) is fastened to the carrier 38 together with the cover 16 using wheel fastening bolts 18. The wheel fastening bolts 18 are bolts that fasten the three components of the wheel 14, cover 16, and carrier 38 together.

[0028] As described above, the in-wheel motor drive unit 10 of this embodiment has the wheel 14 (and the attached tire 12) and cover 16 attached to the outer side in the vehicle width direction, and the stepped pinion 34 is disposed in a position where the end face of the large diameter gear 34a of the stepped pinion 34 faces the cover 16, making the stepped pinion 34 detachable when the wheel 14 (and the attached tire 12) and the cover 16 are removed. This improves the replaceability of the stepped pinion 34.

[0029] Preferably, a ring-shaped rubber seal 22 is disposed between the cover 16 and the carrier 38. The cover fastening bolts 20, which apply tension to the rubber seal 22 to fasten the cover 16 to the carrier 38, are disposed outside the rubber seal 22 and between each of the three stepped pinions 34, as shown in FIG. 1(a). This prevents foreign matter, water, and the like from entering the interior. Furthermore, the rubber seal 22 provides a tight seal simply by attaching the cover 16 with the cover fastening bolts 20, improving the ease of maintenance work.

[0030] Preferably, the wheel fastening bolts 18 that fasten the three components of the wheel 14, cover 16, and carrier 38 together are arranged on the outer periphery side of the cover fastening bolts 20, as shown in Figure 1(a). In this way, by arranging the wheel fastening bolts 18 on the outer periphery side where the axial force is applied, the axial force required for torque transmission is reduced, and the number of wheel fastening bolts can be reduced and the size can be made smaller.

[0031] Next, another embodiment of the present invention will be described. In the following description, parts common to the embodiments will be given the same reference numerals and the description thereof will be omitted. [Example]

[0032] 2, an in-wheel motor drive unit 60 is an example in which the reduction gear mechanism 30 of the in-wheel motor drive unit 10 of the first embodiment is changed to a reduction gear mechanism 70 having four stepped pinions 74. Figure 2(a) is a side view seen from the outside in the vehicle width direction, and Figure 2(b) is a cross-sectional view seen from the rear of the vehicle, with the rotation axis CL used as the reference, and the cross section of the B axis in Figure 2(a) up to the rotation axis CL is on the upper side of the page, and the cross section from the rotation axis CL to the C axis is on the lower side of the page.

[0033] The reduction mechanism 70 is configured as a planetary gear device, and includes a sun gear 72, four stepped pinions 74, a ring gear 76, and a carrier 78.

[0034] The sun gear 72 is connected to and supported by the drive shaft 44 so as to rotate integrally with the drive shaft 44 .

[0035] The stepped pinion 74 includes a large-diameter gear 74a that meshes with the sun gear 72 and a small-diameter gear 74b that meshes with the ring gear 76. The large-diameter gear 74a and the small-diameter gear 74b rotate integrally. As shown in Figure 2(b), the stepped pinion 74 is disposed in a position where the end face of the large-diameter gear 74a faces the cover 66, and is disposed so as to be detachable when the wheel 64 and the cover 66 are removed.

[0036] The ring gear 76 is fixed to the housing 40, which is a non-rotating member.

[0037] The carrier 78 supports the four stepped pinions 74 rotatably and revolvably, and is formed into a shape that allows the wheels 64 and the cover 66 to be fastened together and rotate integrally. The carrier 78 is supported by the bearings 52 and 54 to be rotatable about the rotation axis CL relative to the housing 40.

[0038] The cover 66 and the wheel 64 (and the attached tire 12) are attached in this order to the attachment surface of the carrier 78 on the outer side in the vehicle width direction.

[0039] 2(a), the number and arrangement of rubber seals 80, wheel fastening bolts 18, and cover fastening bolts 20 have been changed in accordance with the change to the stepped pinion 74. Other than the above, the same explanation will be omitted as it is common to the first embodiment, but the basic configuration and function remain the same. Therefore, the same effects as those of the first embodiment can be obtained in this embodiment.

[0040] The above describes in detail an embodiment of the present invention based on the drawings, but what has been described above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0041] 10: In-wheel motor drive unit (vehicle in-wheel motor drive unit) 14, 64: Wheel 16, 66: Cover 30, 70: Reduction mechanism 34, 74: Stepped pinion 34a, 74a: Large diameter gear

Claims

1. An in-wheel motor drive unit for a vehicle, comprising a speed reduction mechanism including a stepped pinion, A wheel and a cover are attached to the outer side in the vehicle width direction, The stepped pinion is disposed at a position where an end face of a large diameter gear of the stepped pinion faces the cover, When the wheel and the cover are removed, the stepped pinion becomes detachable.

1. An in-wheel motor drive unit for a vehicle.

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