Drive device

Abstract

[Problem] To provide a drive device that can be reduced in size. [Solution] A drive device (1) is attached to an attachment member (92) in which an attachment hole (920) is formed, and drives a wheel (91). A drive device (1) is provided with a motor (10), a planetary gear mechanism (12), and a hub unit (13). The planetary gear mechanism (12) and the hub unit (13) are coaxially arranged in the axial direction. The hub unit (13) has an inner member (5) having a hub flange (501) to which the wheel (91) is attached, an outer member (6) fitted and fixed to the attachment hole (920), and a plurality of rolling elements (7). The planetary gear mechanism (12) has a planetary gear (3), a carrier (4) that supports the planetary gear (3), an internal gear section (63) that meshes with the planetary gear (3) on the outer peripheral side of the carrier (4), and a sun gear section (223a) that meshes with the planetary gear (3) on the inner peripheral side of the carrier (4). The carrier (4) and the inner member (5) are connected so as not to rotate relative to each other. The internal gear portion (63) is provided on the inner peripheral portion of the outer member (6).

Description

Technical Field

[0001] The present invention relates to a driving device for driving wheels. Background Art

[0002] Conventionally, electric vehicles powered by electric motors have adopted a so-called in-wheel motor drive system, in which a drive device located inside the wheel rim drives the wheel. This system offers high acceleration responsiveness due to the close proximity between the drive source and the wheels. Furthermore, the independent control of the driving force of the left and right wheels improves cornering performance.

[0003] For example, Patent Document 1 describes an in-wheel motor drive device in which a motor unit that generates driving force, a speed reducer that reduces the speed of the motor unit and outputs the result, and a hub that transmits the output from the speed reducer to a drive wheel are coaxially arranged along the rotation axis of the wheel.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-60286 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] A drive device disposed inside a wheel rim is required to be compact in order to avoid interference with the rim, a suspension arm of a suspension device, etc. Therefore, an object of the present invention is to provide a drive device that can be compacted.

[0009] Means for solving problems

[0010] In order to achieve the above-mentioned object, the present invention provides a drive device, which is installed on a mounting member having a mounting hole formed coaxially with the rotation axis of the wheel, and drives the wheel, wherein the drive device includes an electric motor, a planetary gear mechanism and a hub unit, the planetary gear mechanism reduces the output rotation of the electric motor, the hub unit supports the wheel, the planetary gear mechanism and the hub unit are coaxially arranged along the axial direction of the rotation axis, the hub unit has an inner member, an outer member and a plurality of rolling elements, the inner member has a hub flange for mounting the wheel, and the outer member is fixedly engaged with the hub unit. The mounting hole, the multiple rolling elements are arranged between the inner member and the outer member, the outer member extends around the outer periphery of the planetary gear mechanism, the planetary gear mechanism has a plurality of planetary gears, a planetary gear carrier, an internal gear portion and a sun gear portion, the planetary gear carrier supports the multiple planetary gears, the internal gear portion is meshed with the multiple planetary gears on the outer periphery of the planetary gear carrier, the sun gear portion is meshed with the multiple planetary gears on the inner periphery of the planetary gear carrier, the planetary gear carrier and the inner member are connected in a non-rotatable manner, and the internal gear portion is arranged on the inner periphery of the outer member.

[0011] Effects of the Invention

[0012] According to the present invention, the driving device can be miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing a drive device, a wheel, a mounting member, a brake disc, and a brake device according to an embodiment of the present invention.

[0014] Figure 2 This is a cross-sectional view of the drive unit and its surroundings.

[0015] Figure 3 yes Figure 2 A partial enlarged view of .

[0016] Figure 4 It is a perspective view showing a holding member and one supporting shaft member.

[0017] Figure 5 It is a perspective view showing a connecting member.

[0018] Figure 6 This is a cross-sectional view of the drive device, showing a cross section of the planetary gear mechanism perpendicular to the axial direction, viewed from the vehicle inner side toward the vehicle outer side.

[0019] Figure 7 It is a perspective sectional view showing an outer member. DETAILED DESCRIPTION

[0020] [Implementation Method]

[0021] Reference Figures 1 to 7 The embodiments of the present invention will be described. It should be noted that the embodiments described below are specific examples of preferred embodiments of the present invention, and some parts specifically illustrate various technically preferred technical matters, but the technical scope of the present invention is not limited to these specific forms.

[0022] Figure 1 This is a perspective view showing a drive device 1 according to an embodiment of the present invention, a wheel 91 driven by the drive device 1, a mounting member 92 to which the drive device 1 is mounted, a brake disc 93 that rotates integrally with the wheel 91, and a brake device 94. The wheel 91 includes a metal rim 911 and a rubber tire 912 mounted on the rim 911. The mounting member 92 is connected to the vehicle body via a suspension arm, a shock absorber, and a suspension spring. The brake device 94 generates braking force by pressing a brake pad against the brake disc 93.

[0023] Figure 2 It is a cross-sectional view of the driving device 1 and its surroundings. Figure 3 yes Figure 2 A partial enlarged view of the Figure 2 In the figure, the rotation axis 90 of the wheel 91 is indicated by a dashed line. Hereinafter, the direction parallel to the rotation axis 90 is referred to as the axial direction, and the direction perpendicular to the axial direction is referred to as the radial direction. Furthermore, the side of the wheel 91 relative to the mounting member 92 is referred to as the vehicle outer side, and the opposite side is referred to as the vehicle inner side. The mounting member 92 has a mounting hole 920 formed therein for mounting the drive device 1. The mounting hole 920 is a circular hole formed coaxially with the rotation axis 90 and extends axially through the mounting member 92.

[0024] The drive device 1 functionally comprises a motor 10, a primary reduction mechanism 11 and a planetary gear mechanism 12 for reducing the output rotation of the motor 10, and a hub unit 13 for supporting a wheel 91. The planetary gear mechanism 12 and the hub unit 13 are coaxially arranged and axially aligned around the rotation axis 90. The primary reduction mechanism 11 is disposed between the motor 10 and the planetary gear mechanism 12. The planetary gear mechanism 12 functions as a secondary reduction mechanism, further reducing the output rotation of the motor 10, already reduced by the primary reduction mechanism 11, and transmitting the result to the hub unit 13.

[0025] In addition, the drive device 1 has a pinion 21 mounted on the output shaft 101 of the electric motor 10, a reduction rotating member 22 rotating around the rotation axis 90, a cover 23 covering the reduction rotating member 22, a plurality of planetary gears 3, a planetary gear carrier 4 supporting the plurality of planetary gears 3, an inner member 5 rotating integrally with the planetary gear carrier 4, an outer member 6 engaged and fixed in the mounting hole 920, a plurality of rolling elements 7 arranged between the inner member 5 and the outer member 6, and an end bearing 80 arranged at the end of the outer member 6 on the inner side of the vehicle and supporting the planetary gear carrier 4 so as to be rotatable relative to the outer member 6 as main components.

[0026] The cover 23 is fixed to the mounting member 92 by a plurality of bolts 81. Figure 2 , one of the bolts 81 is shown. The electric motor 10 is, for example, an embedded magnet synchronous motor or a surface magnet synchronous motor, and is secured to the cover 23 by a plurality of bolts 82. The rotation axis 100 of the electric motor 10 is parallel to the rotation axis 90 and offset relative to the rotation axis 90. In this embodiment, when the drive device 1 is mounted on the vehicle, the rotation axis 100 of the electric motor 10 is offset vertically downward relative to the rotation axis 90.

[0027] The primary reduction mechanism 11 is composed of a pinion gear 21 and a portion of the reduction rotation member 22. The planetary gear mechanism 12 is composed of a planetary carrier 4 and a plurality of planetary gears 3, as well as portions of the reduction rotation member 22 and the outer member 6. The hub unit 13 is composed of an inner member 5 and a plurality of rolling elements 7, and a portion of the outer member 6. The components of the drive device 1 are described in detail below.

[0028] The pinion 21 is mounted on the output shaft 101 of the motor 10 in a relatively non-rotatable manner and is rotatably supported by the bearing 83 held by the cover 23 and the bearing 84 held by the mounting member 92. The pinion 21 has a small-diameter gear portion 21a composed of a spur gear between the bearing 83 and the bearing 84. Figure 2 , the pitch circle diameter P1 of the small-diameter gear portion 21 a is shown.

[0029] The reduction rotation member 22 integrally includes a disc portion 221 having a disc shape centered on the rotation axis 90, an outer cylindrical portion 222 extending axially from the outer peripheral end of the disc portion 221 toward the inner side of the vehicle, and a shaft portion 223 extending axially from the center of the disc portion 221 toward the outer side of the vehicle. The outer cylindrical portion 222 is supported by the cover 23 via a bearing 85 disposed on its inner side. A large-diameter gear portion 222a is formed on the outer cylindrical portion 222, which meshes with the small-diameter gear portion 21a of the pinion 21. A sun gear portion 223a, which constitutes a portion of the planetary gear mechanism 12, is formed on the outer periphery of the shaft portion 223. The sun gear portion 223a rotates integrally with the large-diameter gear portion 222a.

[0030] Like the small-diameter gear portion 21a of the pinion gear 21, the large-diameter gear portion 222a of the reduction rotating member 22 is a spur gear with a tooth trace parallel to the axial direction. The pitch diameter P2 of the large-diameter gear portion 222a is larger than the pitch diameter P1 of the small-diameter gear portion 21a. The primary reduction mechanism 11 is constructed by meshing the small-diameter gear portion 21a of the pinion gear 21 with the large-diameter gear portion 222a of the reduction rotating member 22. The reduction rotating member 22 rotates at a lower speed and higher torque than the output shaft 101 of the electric motor 10.

[0031] The shaft portion 223 of the reduction rotation member 22 is arranged at the center of the planetary gear carrier 4. The sun gear portion 223a is composed of helical teeth with a tooth line inclined relative to the axial direction, and meshes with the multiple planetary gears 3. The pitch circle diameter P3 of the sun gear portion 223a is formed to be smaller than the pitch circle diameter P2 of the large-diameter gear portion 222a. The planetary gear carrier 4 is constructed to include: a retaining member 41, which is formed with multiple retaining portions 40 that respectively retain the multiple planetary gears 3; a connecting member 42 that prevents the planetary gears 3 from escaping from the retaining portions 40 and connects the retaining member 41 to the inner member 5; a plurality of support shaft members 43 arranged between the retaining member 41 and the connecting member 42, which respectively support the multiple planetary gears 3; and a plurality of bolts 44 that secure the retaining member 41 to the connecting member 42.

[0032] Figure 4 It is a perspective view showing the holding member 41 and one supporting shaft member 43 . Figure 5 It is a perspective view showing the connecting member 42 . Figure 6 This is a cross-sectional view of the drive device 1 , showing a cross section of the planetary gear mechanism 12 perpendicular to the axial direction, viewed from the vehicle interior toward the vehicle exterior. Figure 7 It is a perspective sectional view showing the outer member 6 .

[0033] The retaining member 41 integrally comprises a disc-shaped base portion 411 centered about the rotation axis 90, a flange portion 412 provided at the vehicle-interior end of the base portion 411, and a plurality of leg shaft portions 413 extending axially from the base portion 411 to protrude outward from the vehicle. A through-hole 411a is formed in the center of the base portion 411 for inserting the shaft portion 223 of the reduction rotation member 22. The flange portion 412 is formed in an annular shape and radially protrudes from the outer peripheral surface 411b of the base portion 411.

[0034] A plurality of foot shaft portions 413 are arranged at equal intervals along the circumference centered on the rotation axis 90, and a holding portion 40 is formed between the plurality of foot shaft portions 413. In this embodiment, the planetary gear mechanism 12 has three planetary gears 3, and three foot shaft portions 413 are provided on the holding member 41. A bolt insertion hole 413a for inserting a bolt 44 is formed in each foot shaft portion 413. Figure 2As shown, the bolt 44 includes a cylindrical insertion portion 441 inserted into the bolt insertion hole 413 a , a head portion 442 having a larger diameter than the insertion portion 441 , and an external thread portion 443 threadedly engaged with the connecting member 42 .

[0035] The support shaft member 43 integrally includes a large-diameter portion 431 inserted through the center of the planetary gear 3 and a pair of small-diameter portions 432 and 433 provided at either end of the large-diameter portion 431. A fitting hole 411c is formed in the base 411 of the retaining member 41, into which the small-diameter portion 432 on the vehicle interior side of the pair of small-diameter portions 432 and 433 of the support shaft member 43 fits. The small-diameter portion 433 on the vehicle exterior side fits into a fitting hole 421a of the connecting member 42, described below.

[0036] The connecting member 42 integrally comprises: a disc-shaped cap portion 421 that closes the openings of the plurality of retaining portions 40 on the vehicle exterior to prevent the plurality of planetary gears 3 from falling off; a spline shaft portion 422 that extends from the center of the cap portion 421 toward the vehicle exterior; and an external thread portion 423 that is provided at the end portion on the vehicle exterior. A recess 420 that is axially recessed toward the vehicle exterior is formed in the center of the cap portion 421. Figure 2 As shown, the bearing 86 that supports the shaft portion 223 of the reduction rotation member 22 is housed in the recessed portion 420 .

[0037] The cap portion 421 is formed with a plurality of fitting holes 421a into which the small-diameter portion 433 on the vehicle exterior of the support shaft member 43 fits, and a plurality of threaded holes 421b into which the externally threaded portion 443 of the bolt 44 screws. The plurality of fitting holes 421a and the plurality of threaded holes 421b are alternately arranged along the circumference of the cap portion 421. The distal end surface 413b of the foot shaft portion 413 abuts against the cap portion 421 of the connecting member 42 due to the axial force of the bolt 44. A plurality of axially extending spline teeth 422a are formed on the outer circumference of the spline shaft portion 422. The spline shaft portion 422 is inserted through the center portion of the inner member 5.

[0038] like Figure 3 As shown, the planetary gears 3 are supported on the outer circumference of the large diameter portion 431 of the support shaft member 43 via bearings 87. Bearings 87 are needle roller bearings having a plurality of needle rollers 871 and a retainer 872 that holds the plurality of needle rollers 871. In this embodiment, two bearings 87 are disposed between the large diameter portion 431 of the support shaft member 43 and the planetary gears 3.

[0039] The outer member 6 extends along the outer periphery of the planetary gear mechanism 12. An internal gear portion 63 is provided on the inner periphery of the outer member 6, meshing with the plurality of planetary gears 3. The planetary gear mechanism 12 comprises a plurality of planetary gears 3, a planetary carrier 4, an internal gear portion 63 meshing with the plurality of planetary gears 3 on the outer periphery of the planetary carrier 4, and a sun gear portion 223a of the reduction rotation member 22 meshing with the plurality of planetary gears 3 on the inner periphery of the planetary carrier 4. Details of the structure of the outer member 6 will be described later.

[0040] The inner member 5 consists of a hub 51 having a centrally formed engagement hole 50 into which the splined shaft 422 of the connecting member 42 is spline-engaged, and an inner ring 52 externally engaged with the vehicle-inside end of the hub 51. Nuts 88 are threadedly engaged with the externally threaded portion 423 of the connecting member 42, which protrudes from the engagement hole 50 toward the vehicle's exterior. The planetary gear carrier 4 is non-rotatably connected to the inner member 5 by spline-engaging the splined shaft 422 of the connecting member 42 with the engagement hole 50.

[0041] The inner ring 52 is prevented from falling off from the hub 51 by abutting against the cap portion 421 of the connecting member 42. Alternatively, the inner ring 52 may be prevented from falling off by tightening the end portion of the hub 51 on the vehicle inner side.

[0042] The plurality of rolling elements 7 are arranged between the inner member 5 and the outer member 6 to form multiple rolling element rows. More specifically, the plurality of rolling elements 7 constitute a first rolling element row 71 on the wheel 91 side and a second rolling element row 72 on the planetary gear mechanism 12 side. The plurality of rolling elements 7 in the first rolling element row 71 are held by a first retainer 701 and roll on a first inner raceway 51a formed on the hub ring 51. The plurality of rolling elements 7 in the second rolling element row 72 are held by a second retainer 702 and roll on a second inner raceway 52a formed on the inner ring 52. In this embodiment, the rolling elements 7 are spherical, but this is not limiting and the rolling elements 7 may also be tapered rollers.

[0043] The inner member 5 includes a hub flange 501 to which the rim 911 of the wheel 91 is mounted, and a hub cylindrical portion 502 located inside the first and second rolling element rows 71, 72. The hub flange 501 is a portion of the hub rim 51. The hub cylindrical portion 502 is composed of a portion of the hub rim 51 and the inner ring 52. A first inner raceway surface 51a and a second inner raceway surface 52a are formed on the outer circumference of the hub cylindrical portion 502.

[0044] Hub bolts 95 for attaching the brake disc 93 and the rim 911 of the wheel 91 are fixed to the hub flange 501. The hub bolts 95 are press-fitted into bolt holes 501a formed in the hub flange 501, and the hub nuts 96 are screwed into their distal ends. Alternatively, an internally threaded hole may be formed in the hub flange 501, and the hub bolts may be screwed into the internally threaded hole.

[0045] The outer member 6 includes a cylindrical portion 61 that is engaged with the mounting hole 920 of the mounting member 92, a flange portion 62 that is fixed to the open end surface 920a of the mounting hole 920 in the mounting member 92, and an internal gear portion 63 that is arranged on the inner side of the cylindrical portion 61. In the present embodiment, the cylindrical portion 61, the flange portion 62, and the internal gear portion 63 are formed as a whole. However, the present invention is not limited to this, and the cylindrical portion 61 and the internal gear portion 63 may also be separate bodies, for example, connected in a manner that cannot rotate relative to each other by spline engagement. That is, the internal gear portion 63 may be arranged on the inner side of the cylindrical portion 61 as a whole with the cylindrical portion 61, or may be arranged on the inner side of the cylindrical portion 61 in a manner that rotates as a whole with the cylindrical portion 61.

[0046] The cylindrical portion 61 is formed so that its outer diameter is slightly smaller than the inner diameter of the mounting hole 920 and is inserted into the mounting hole 920 from the vehicle's outer side toward the vehicle's inner side. The cylindrical portion 61 includes a first portion 611 located outside the hub cylindrical portion 502 of the inner member 5 and a second portion 612 located closer to the vehicle's inner side than the first portion 611. A sealing member 89 is disposed between the vehicle's outer end of the first portion 611 and the hub wheel 51. A portion of the first portion 611 is accommodated in the mounting hole 920 in the axial direction. The second portion 612 is entirely accommodated in the mounting hole 920 and is disposed on the outer periphery of the retaining member 41 and the cap portion 421 of the connecting member 42.

[0047] The hub unit 13 is composed of the inner member 5, the flange portion 62 of the outer member 6, the first portion 611 of the cylindrical portion 61, a plurality of rolling elements 7, a first retainer 701 and a second retainer 702, and a sealing member 89. A first outer raceway surface 611a on which the plurality of rolling elements 7 of the first rolling element row 71 roll, and a second outer raceway surface 611b on which the plurality of rolling elements 7 of the second rolling element row 72 roll, are formed in the first portion 611 of the cylindrical portion 61.

[0048] In this embodiment, if Figure 6 As shown, the flange portion 62 is composed of a plurality of flange pieces 621, which are radially arranged to protrude outward from the first portion 611 of the cylindrical portion 61. However, the flange portion 62 may also be arranged in an annular shape on the outer circumference of the cylindrical portion 61. The mounting member 92 has threaded holes 92b formed in the open end surface 920a, into which bolts 97 for securing the flange portion 62 are screwed. The open end surface 920a is the end surface of the mounting member 92 on the vehicle's outer side, surrounding the opening of the mounting hole 920. Each flange piece 621 has a bolt insertion hole 62a formed at a position corresponding to the threaded hole 92b. The outer member 6 is secured to the mounting member 92 by screwing the bolts 97 inserted through the bolt insertion holes 62a into the threaded holes 92b.

[0049] like Figure 7 As shown, the internal gear portion 63 is formed with a plurality of helical teeth 63a whose tooth lines are inclined relative to the axial direction. The internal gear portion 63 meshes with the helical teeth 3a of the plurality of planetary gears 3. A bearing fitting portion 612a, into which the end bearing 80 fits, is formed at the end portion on the vehicle inner side of the second portion 612 of the cylindrical portion 61.

[0050] The end bearings 80 are ball bearings, such as Figure 3 As shown, the outer ring 801 and inner ring 802 are provided, along with a plurality of rolling elements 803 disposed between the outer ring 801 and the inner ring 802. The outer ring 801 is held by the bearing engagement portion 612a of the outer member 6, with its side surface 801a on the vehicle's outer side contacting the vehicle's inner end surface 63b of the internal gear portion 63. The inner ring 802 is disposed on the outer periphery of the base portion 411 of the retaining member 41, with its side surface 802a on the vehicle's inner side facing the flange portion 412 of the retaining member 41.

[0051] The end bearing 80 is positioned axially of the drive device 1 at a position farther from the hub unit 13 than the internal gear portion 63. The internal gear portion 63 is disposed between the end bearing 80 and the second rolling element row 72 on the planetary gear mechanism 12 side of the first and second rolling element rows 71 and 72. This arrangement of the end bearing 80 prevents the internal gear portion 63 and the planetary gears 3 from tilting slightly relative to the rotation axis 90 due to torque applied to the hub unit 13 by external forces acting on the wheels 91 during vehicle travel. Furthermore, the planetary carrier 4 and the inner member 5 are rotatably supported relative to the outer member 6 at multiple axially separated locations. This prevents tilting of the carrier 4 and the inner member 5 relative to the outer member 6. This effectively maintains meshing of the internal gear portion 63 and the planetary gears 3.

[0052] It should be noted that even when the planetary gear carrier 4 and the internal component 5 are tilted relative to the rotation axis 90, in order to maintain good engagement between the planetary gear 3 and the sun gear portion 223a of the reduction rotating component 22, it is preferred to perform tooth profile correction such as drum finishing on the sun gear portion 223a.

[0053] According to the embodiment described above, the drive device 1 can be miniaturized by providing the internal gear portion 63 meshing with the plurality of planetary gears 3 on the inner circumference of the outer member 6 fitted and fixed to the mounting hole 920 of the mounting member 92 .

[0054] (Note)

[0055] While the present invention has been described above based on the embodiments, these embodiments do not limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessarily required to achieve the objectives of the invention. Furthermore, the present invention may be implemented with some configurations omitted, or with additions or substitutions, or with appropriate modifications, without departing from its spirit.

[0056] Label Description

[0057] 1…Drive unit

[0058] 10…Electric motor

[0059] 101…output shaft

[0060] 11…First-stage reduction mechanism

[0061] 12…Planetary gear mechanism

[0062] 13…Hub unit

[0063] 21…pinion

[0064] 22…Deceleration rotating component

[0065] 222a…Large diameter gear

[0066] 223…Shaft

[0067] 223a…Sun gear unit

[0068] 3…Planetary gears

[0069] 4…Planetary gear carrier

[0070] 5…Inner member

[0071] 501…wheel hub flange

[0072] 6…External member

[0073] 61…cylindrical part

[0074] 62…flange

[0075] 63…Internal gear

[0076] 7…Rolling elements

[0077] 71…First rolling element row

[0078] 72…Second rolling element row

[0079] 80…end bearing

[0080] 90...rotation axis

[0081] 91…wheels

[0082] 92…Installation components

[0083] 920…Mounting hole

Claims

1. A driving device mounted on a mounting member having a mounting hole formed coaxially with a rotation axis of a wheel, and driving the wheel, wherein: The drive device includes an electric motor, a planetary gear mechanism that reduces output rotation of the electric motor, and a hub unit that supports the wheel. The planetary gear mechanism and the hub unit are coaxially arranged in an axial direction along the rotation axis. The hub unit includes an inner member, an outer member, and a plurality of rolling elements. The inner member includes a hub flange for mounting the wheel. The outer member is fitted and fixed in the mounting hole. The plurality of rolling elements are arranged between the inner member and the outer member. The outer member extends around the outer periphery of the planetary gear mechanism. The planetary gear mechanism includes a plurality of planetary gears, a planetary gear carrier, an internal gear portion, and a sun gear portion. The planetary gear carrier supports the plurality of planetary gears. The internal gear portion meshes with the plurality of planetary gears on the outer peripheral side of the planetary gear carrier. The sun gear portion meshes with the plurality of planetary gears on the inner peripheral side of the planetary gear carrier. The planetary gear carrier and the inner member are connected in a manner that is non-rotatable relative to each other. The internal gear portion is provided on the inner peripheral portion of the outer member.

2. The driving device according to claim 1, wherein: The drive device includes a bearing that supports the planetary carrier so as to be rotatable relative to the outer member. The bearing is arranged at a position farther from the hub unit than the internal gear portion in the axial direction.

3. The driving device according to claim 2, wherein: The plurality of rolling elements are arranged between the inner member and the outer member to form a plurality of rolling element rows. The internal gear portion is provided between the rolling element row on the planetary gear mechanism side of the plurality of rolling element rows and the bearing.

4. The driving device according to claim 1, wherein: The outer member integrally includes: a cylindrical portion fitted into the mounting hole; a flange portion fixed to an opening end surface of the mounting hole in the mounting member; and the internal gear portion.

5. The driving device according to any one of claims 1 to 4, wherein: The drive device further includes a primary reduction mechanism disposed between the motor and the planetary gear mechanism. The primary reduction mechanism is formed by meshing a small-diameter gear portion of a pinion mounted on the output shaft of the electric motor with a large-diameter gear portion of a reduction rotation member, wherein the reduction rotation member has the large-diameter gear portion having a larger pitch circle diameter than the small-diameter gear portion. The sun gear portion rotates integrally with the large-diameter gear portion.

6. The driving device according to claim 5, wherein: The reduction rotation member includes a shaft portion, the shaft portion being disposed at the center portion of the planetary gear carrier, and the sun gear portion being formed on the outer periphery of the shaft portion. The pitch circle diameter of the sun gear portion is smaller than the pitch circle diameter of the large-diameter gear portion.

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