CN111071030B

CN111071030B - Wheel driving device

Info

Publication number: CN111071030B
Application number: CN201910688612.7A
Authority: CN
Inventors: 田村光扩
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2018-10-18
Filing date: 2019-07-29
Publication date: 2023-06-23
Anticipated expiration: 2039-07-29
Also published as: DE102019123061A1; JP7362240B2; CN111071030A; JP2020063795A

Abstract

The invention provides a wheel driving device capable of shortening axial dimension. A wheel drive device (1) of the present invention is provided with: an internal gear member (33) having an internal gear; an external gear (35); a wheel carrier (45) that synchronizes with the rotation component or revolution component of the external gear (35); main bearings (51A, 51B) disposed between the internal gear member and the wheel carrier; and a wheel (11) that rotates integrally with the internal gear member. The wheel carrier (45) has an extension (45B) disposed radially outward of the internal gear member, and the main bearings (51A, 51B) are disposed between the extension (45B) and the internal gear member (33), with the outer peripheral portion of the wheel (11) being disposed radially outward of the extension (45B).

Description

Wheel driving device

The present application claims priority based on japanese patent application No. 2018-196339 filed on 10 months and 18 days of 2018. The entire contents of this japanese application are incorporated by reference into the present specification.

Technical Field

The present invention relates to a wheel drive device.

Background

Fig. 1 of patent document 1 discloses a wheel drive device in which a speed reducer is incorporated into a wheel of an unmanned conveyance vehicle. The wheel driving device is provided with: an external gear 20 that swings by rotation of the eccentric body 19; an internal gear 23 coupled to the wheel 12; and main bearings 15, 16 disposed between the frame 13 and the wheels 12. The main bearings 15, 16 are provided at one side and the other side in the axial direction so as to sandwich the external gear 20.

Patent document 1: japanese patent laid-open No. 62-80324

The conventional wheel drive device with a built-in speed reducer has a problem of a large axial dimension.

Disclosure of Invention

The invention aims to provide a wheel driving device capable of shortening axial dimension.

A wheel drive device according to the present invention includes: an internal gear member having an internal gear; an external gear; a wheel carrier that is synchronized with a rotation component or a revolution component of the external gear; a main bearing disposed between the internal gear member and the wheel carrier; and a wheel that rotates integrally with the internal gear member, wherein the wheel carrier has an extension portion disposed radially outward of the internal gear member, the main bearing is disposed between the extension portion and the internal gear member, and an outer peripheral portion of the wheel is disposed radially outward of the extension portion.

Another wheel drive device according to the present invention includes: an internal gear member having an internal gear; an external gear; a wheel carrier that is synchronized with a rotation component or a revolution component of the external gear; a main bearing disposed between the internal gear member and the wheel carrier; and a wheel that rotates integrally with the wheel carrier, wherein the wheel carrier has an extension portion disposed radially outward of the internal gear member, the main bearing is disposed between the extension portion and the internal gear member, and an outer peripheral portion of the wheel is disposed radially outward of the extension portion.

According to the present invention, a wheel drive device having a shortened axial dimension can be provided.

Drawings

Fig. 1 is a partially cut-away side view showing a wheel drive device according to embodiment 1 of the present invention.

Fig. 2 is a view of the wheel drive device of embodiment 1 as seen from the opposite side of the motor in the axial direction.

Fig. 3 is a view of the wheel drive device according to embodiment 1 as seen from the motor side in the axial direction.

Fig. 4 is a cross-sectional view showing a wheel drive device according to embodiment 2 of the present invention.

In the figure: 1. the wheel drive apparatus includes 11, 111-wheels, 11A, 111A-rim portion (2 nd axial extension), 11B, 111B-rim portion (2 nd radial extension), 11c, 111 c-tire portion, 21, 121-motor, 23, 123-motor shaft, 25, 125-housing, 25a, 125 a-screw hole, 31, 131-reduction mechanism, 33, 133-internal tooth member, 35, 135-external gear, 37, 137-eccentric body, 43, 143-internal pin, 45, 145-wheel carrier, 45 a-base portion (1 st radial extension), 145 a-1 st radial extension, 45B-extension (1 st axial extension), 145B-1 st axial extension, 45 f-flange portion, 45k, 125 k-notch portion, 51A, 51B, 151A, 151B-main bearing, 53A, 53B, 153-input bearing, O1-rotation shaft (rotation center axis), and G0-running surface (wheel running surface).

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(embodiment 1)

Fig. 1 is a partially cut-away side view showing a wheel drive device according to embodiment 1 of the present invention. Fig. 2 is a view of the wheel drive device of embodiment 1 as seen from the opposite side of the motor in the axial direction. Fig. 3 is a view of the wheel drive device according to embodiment 1 as seen from the motor side in the axial direction. The cutaway portion of fig. 1 shows the cross-section of fig. 2 along the arrow A-A. In fig. 2 and 3, the wheel 11 is indicated by a two-dot chain line. In the present specification, a direction along the rotation axis O1 is defined as an axial direction, a direction perpendicular to the rotation axis O1 is defined as a radial direction, and a direction rotating around the rotation axis O1 is defined as a circumferential direction.

The wheel drive device 1 according to embodiment 1 is attached to, for example, a main body of an unmanned conveyor (a carriage) to constitute a motor-equipped wheel of the unmanned conveyor. The wheel drive device 1 includes a wheel 11, a motor 21, and a reduction mechanism 31. Hereinafter, the direction from the reduction mechanism 31 toward the motor 21 in the axial direction is referred to as a motor side, and the direction from the motor 21 toward the reduction mechanism 31 is referred to as a side opposite to the motor.

The wheel 11 includes a tire portion 11c provided on an outer peripheral portion, a rim portion 11a to which the tire portion 11c is attached, and a disc portion 11b supporting the rim portion 11 a. The tire portion 11c has elasticity, and its thickness becomes smaller with use. The wheel disc portion 11b is provided on the opposite side of the device from the motor so as to extend in the radial direction and is coupled to the reduction mechanism 31. The rim portion 11a has a tubular shape, and extends from the outer peripheral portion of the rim portion 11b toward the motor side in the axial direction. The disk portion 11b corresponds to an example of the 2 nd radial extension portion according to the present invention, and the rim portion 11a corresponds to an example of the 2 nd axial extension portion according to the present invention.

The motor 21 includes a motor shaft 23 that rotates around a rotation axis O1, a rotor (not shown), a stator, a brake unit, and a housing 25, and the motor 21 drives the motor shaft 23 to rotate by electric power. The case 25 is provided with a screw hole 25a connected to the main body of the unmanned conveyor.

The reduction gear mechanism 31 is an eccentric oscillating type reduction gear, and includes an internal gear member 33, an external gear 35, an eccentric body 37, an eccentric body bearing 41, an internal pin 43, a carrier 45, a cover 49, a main bearing 51A, a main bearing 51B, an input bearing 53A, an input bearing 53B, and a counter weight 55.

The external gear 35 has a plurality of internal pin holes 35a and a central hole provided at a plurality of locations on the circumference of the same radius, in addition to external teeth.

The eccentric body 37 is coupled to the motor shaft 23 by, for example, a key connection, and rotates integrally with the motor shaft 23. The eccentric body 37 is assembled to penetrate the center hole of the external gear 35 in the axial direction. An eccentric body bearing 41 is disposed between the eccentric body 37 and the external gear 35, and the eccentric body 37 is rotatable relative to the external gear 35 inside the external gear 35. The external gear 35 performs eccentric oscillation by rotation of the eccentric body 37.

The internal tooth member 33 has: an internal gear body 33a provided with a plurality of pin grooves on an inner peripheral portion thereof; a plurality of outer pins 33b rotatably supported by the plurality of pin grooves, respectively; and holding

members

33c, 33d coupled to the inner gear main body 33a to hold the plurality of outer pins 33b. The plurality of pin grooves are arranged in a circumferential direction. The internal gear body 33a and the plurality of outer pins 33b function as an internal gear. The number of teeth of the internal tooth member 33 (the number of external pins 33 b) is different from the number of teeth of the external gear 35 (for example, the difference in number of teeth is 1). An external gear 35 is disposed inside the internal gear member 33, and external teeth of the most eccentric portion of the external gear 35 mesh with the external pin 33b (internal teeth).

The

main bearings

51A and 51B are, for example, ball bearings, and rotatably support the internal gear member 33 about the rotation axis O1.

The carrier 45 is disposed on one side (motor side) of the external gear 35 in the axial direction, and holds the plurality of internal pins 43. The plurality of inner pins 43 axially penetrate the plurality of inner pin holes 35a of the external gear 35, respectively. The wheel frame 45 has: a base portion 45a integrated with the housing 25 of the motor 21; an annular holding frame 45c for holding the plurality of inner pins 43; and a tubular extension 45b extending from the base 45a toward a side opposite to the motor in the axial direction. The holding frame 45c is coupled to the base portion 45a by bolts or the like. The carrier 45 is engaged with the external gear 35 via the plurality of internal pins 43, whereby the movement of the carrier 45 (including stationary based on fixation) is synchronized with the rotation component of the external gear 35. The base portion 45a corresponds to an example of the 1 st radial extension portion of the present invention, and the extension portion 45b corresponds to an example of the 1 st axial extension portion of the present invention.

The counterweight 55 is keyed to the motor shaft 23, and, when the motor shaft 23 rotates, the balance weight 55 rotates to generate a load opposite to a load generated based on the swing of the external gear 35. Specifically, the counterweight 55 has a center of gravity on the side opposite to the eccentric direction of the eccentric body 37.

The

input bearings

53A and 53B rotatably support the motor shaft 23 on one side and the other side in the axial direction of the external gear 35. One input bearing 53A is disposed between the wheel carrier 45 and the motor shaft 23, and the other input bearing 53B is disposed between the cover 49 and the motor shaft 23. The cover 49 covers the motor shaft 23 and the input bearing 53B on the opposite side to the motor, and is coupled to the internal gear member 33. In addition to the

input bearings

53A and 53B of the reduction mechanism 31, the motor-side end of the motor shaft 23 is rotatably supported by a bearing 27 provided in the motor 21.

< speed-reducing action >)

When the motor shaft 23 is rotated by driving the motor 21, the eccentric body 37 is rotated to eccentrically oscillate the external gear 35. As the eccentric body 37 rotates, the counterweight 55 rotates, and a load in a direction opposite to a load generated by the eccentric oscillation of the external gear 35 is generated, thereby maintaining the rotational balance inside the reduction mechanism 31. The external gear 35 is connected to the wheel carrier 45 via the internal pin 43, and the wheel carrier 45 is fixed to the housing 25 of the motor 21. Therefore, the rotation component of the external gear 35 becomes zero in synchronization with the carrier 45, and the external gear 35 merely eccentrically swings and does not rotate (spin).

On the other hand, the meshing position of the external teeth of the external gear 35 with the internal teeth of the internal gear member 33 varies in the circumferential direction with the eccentric oscillation of the external gear 35. Therefore, each 1 rotation of the eccentric body 37, the internal gear member 33 rotates (self-transmits) by an amount corresponding to the difference (for example, 1 tooth) in the number of teeth between the internal gear of the internal gear member 33 and the external gear 35. As a result, the rotational movement of the motor 21 is decelerated at a reduction ratio of 1/(the number of teeth of the internal gear) and then output to the wheel 11 integrated with the internal gear member 33. By the rotation of the wheel 11, the unmanned conveyance device travels on the traveling surface G0.

< extension Structure of each component >)

The wheel carrier 45 and the wheel 11 that rotates integrally with the internal gear member 33 have symmetrical extended structures. That is, the base portion (1 st radially extending portion) 45a of the carrier 45 extends radially outward from a portion (holding frame 45c; may also be referred to as carrier body) where the plurality of inner pins 43 are held, on one side (motor side: 1 st direction side) in the axial direction of the external gear 35. Further, an extension portion 45b (1 st axial extension) of the wheel carrier 45 extends from the base portion 45a toward the other side in the axial direction (the side opposite to the motor). The extension portion 45b has a flange portion 45f extending radially outward on the motor side, and the flange portion 45f is coupled to the base portion 45a by bolts or the like.

The disc portion (2 nd radially extending portion) 11b of the wheel 11 extends radially on the opposite side (opposite side to the 1 st direction side) of the motor from the external gear 35. Further, a rim portion (2 nd axially extending portion) 11a of the wheel 11 extends from an outer peripheral portion of the wheel disc portion 11b toward the motor side in the axial direction.

By such an extending structure of the wheel carrier 45 and an extending structure of the wheel 11 integrated with the internal gear member 33, it is possible to realize a structure in which the internal gear body 33a, the

main bearings

51A, 51B, the extending portion (1 st axial extending portion) 45B of the wheel carrier 45, the rim portion (2 nd axial extending portion) 11A of the wheel 11, and the tire portion 11c are disposed in this order from the outer pin 33B of the internal gear member 33 toward the radial outside. The

main bearings

51A and 51B are disposed between (the inner periphery of) the extension portion 45B of the carrier 45 and (the outer periphery of) the internal gear member 33, and thereby support the internal gear member 33 rotatably with respect to the carrier 45.

As described above, the

main bearings

51A and 51B can be arranged radially outside the inner teeth member 33, and thus the

main bearings

51A and 51B can be arranged without increasing the axial dimension of the reduction gear mechanism 31. Although not particularly limited, as a preferable example, the

main bearings

51A and 51B are arranged such that both ends in the axial direction of the

main bearings

51A and 51B are located further inward than both ends in the axial direction of the two

input bearings

53A and 53B when viewed in the radial direction. Unlike the example of fig. 1, the

main bearings

51A and 51B may be disposed such that both ends in the axial direction of the

main bearings

51A and 51B are located at positions inward of both ends in the axial direction of the tire portion 11 c. The two ends of the plurality of bearings are: the space portions of the plurality of bearings are also regarded as a part of the bearings, and the plurality of bearings are regarded as both ends when they are integrated.

Further, as a preferable example, although not particularly limited, the two

main bearings

51A, 51B may be arranged so that at least a part of each main bearing overlaps the outer pin 33B when viewed in the radial direction. Further, as a preferable example, although not particularly limited, the two

main bearings

51A, 51B may be arranged so that at least a part of each main bearing overlaps the external gear 35 when viewed in the radial direction.

In addition, instead of the two

main bearings

51A, 51B, one main bearing (for example, a cross roller bearing or the like) may be used. In this case, as a preferable example, one main bearing is disposed such that both ends in the axial direction thereof are located further inside than both ends in the axial direction of the

input bearings

53A, 53B. Further, as a preferable example, one main bearing may be arranged such that at least a part thereof overlaps the outer pin 33b when viewed in the radial direction. Further, as a preferable example, one main bearing may be arranged so that at least a part thereof overlaps with the external gear 35 when viewed in the radial direction.

Although the example of fig. 1 shows a structure having one external gear 35, a plurality of external gears may be arranged in an axial direction. In this case, regarding whether or not the external gear overlaps the main bearing when viewed in the radial direction, it is sufficient to determine whether or not the main bearing overlaps the external gear when the plurality of external gears are regarded as one body (that is, when the space portions of the plurality of external gears are also regarded as a part of the external gears).

Detailed description of the extension of the wheel frame

The extending portion 45b of the wheel frame 45 extends to a position of an inner Zhou Duizhi of a corner portion between the rim portion 11b and the rim portion 11a of the wheel 11. Further, an inclined surface S45 is provided on the outer peripheral surface of the distal end portion of the extension portion 45b, and the inclined surface S45 is inclined so that the diameter thereof becomes smaller toward the side opposite to the motor (distal end side).

The wheel 11 has a thick portion 11v having a larger thickness for reinforcement on the inner periphery of the corner portion between the wheel disc portion 11b and the rim portion 11 a. By adopting the inclined surface S45 at the distal end portion of the extending portion 45b, even if the wheel 11 and the wheel frame 45 are disposed close to each other in the axial direction, interference between the thick portion 11v of the wheel 11 and the distal end portion of the extending portion 45b of the wheel frame 45 can be suppressed.

The flange portion 45f of the extending portion 45b of the wheel carrier 45 is provided within a range overlapping the tire portion 11c of the wheel 11 when viewed in the axial direction (refer to fig. 2 and 3). According to this structure, when the wheel 11 is detached, the flange portion 45f is exposed on the side opposite to the motor, and the operability of connecting the flange portion 45f to the base portion 45a is improved. Further, the radial dimension of the motor 21 or the reduction gear 31 can be increased and the axial dimension can be shortened as compared with the case where the flange portion 45f is provided radially inward.

On the other hand, in the outermost peripheral portion (flange portion 45 f) of the wheel frame 45, a notch portion 45k having a distance L1 from the rotation axis O1 smaller than the outer radius L2 of the rim portion 11a of the wheel 11 is provided at least in a range facing the running surface G0. By the notch 45k, even when the thickness of the tire portion 11c becomes smaller with use of the wheel 11, it is possible to avoid a part of the wheel frame 45 from contacting the running surface G0 during the decrease of the tire portion 11 c. The notch 45k is not limited to a surface parallel to the running surface G0, and may be formed of a curved surface, for example.

Further, notch portions 45k, each having a distance L1 from the rotation axis O1 of the outermost peripheral portion (flange portion 45 f) of the wheel carrier 45 smaller than the outer radius L2 of the rim portion 11a, are provided at a plurality of positions (for example, four positions in the vertical and horizontal directions in fig. 2 and 3) in the circumferential direction of the wheel carrier 45. According to this configuration, the degree of freedom in the mounting angle (circumferential angle) of the wheel drive device 1 when the wheel drive device 1 is mounted on the main body of the unmanned conveyance device can be improved. That is, the wheel drive device 1 may be mounted at an angle at which the optional notch 45k is located below, and even when the tire portion 11c is small, a part of the wheel carrier 45 can be prevented from contacting the running surface G0 by the notch 45k. Such a degree of freedom in the mounting angle can improve, for example, fixation of wiring of the motor 21 and handling operability.

Effect of the embodiments >

As described above, according to the wheel drive device 1 of embodiment 1, the

main bearings

51A and 51B are disposed between the extending portion 45B of the wheel frame 45 and the internal gear member 33, and the outer peripheral portion of the wheel 11 is disposed radially outward of the extending portion 45B of the wheel frame 45. By adopting such an arrangement, the

main bearings

51A, 51B and the wheel 11 can be arranged so as to overlap the internal gear member 33 in the radial direction, and the axial dimension of the wheel drive device 1 can be shortened. The unmanned aerial vehicle may be equipped with a battery for accumulating the electric power of the motor 21 at the same height as the wheel drive device 1. In this case, since the axial dimension of the wheel drive device 1 can be reduced, the space for mounting the battery can be increased, and the effect of being able to mount a larger battery can be obtained.

Further, according to the wheel driving apparatus 1 of embodiment 1, the wheel carrier 45 has: a base portion 45a extending in the radial direction on one side (motor side) of the external gear 35 in the axial direction; and an extension portion 45b extending from the base portion 45a toward the other side (the side opposite to the motor) in the axial direction. The wheel 11 integrated with the internal gear member 33 includes: the wheel disc portion 11b extending in the radial direction on the other side (the side opposite to the motor) of the external gear 35 in the axial direction; and a rim portion 11a extending from the wheel disc portion 11b toward one side (motor side) in the axial direction. By adopting the above configuration, the above configuration can be realized in which the axial dimension is shortened, and a mechanism can be realized in which the carrier 45 and the internal gear member 33 are relatively rotated.

Further, according to the wheel driving apparatus 1 of embodiment 1, the extending portion 45b of the wheel carrier 45 has the flange portion 45f extending toward the radially outer side, and the flange portion 45f is coupled to the base portion 45a. The flange portion 45f is arranged so as to overlap the tire portion 11c when viewed from the axial direction. Thereby, the assembly of the

main bearings

51A, 51B and the assembly of the wheel carrier 45 are facilitated. Further, the axial dimension of the wheel drive device 1 can be shortened as compared with the case where the flange portion 45f is extended radially inward.

(embodiment 2)

Fig. 4 is a cross-sectional view showing a wheel drive device 101 according to embodiment 2 of the present invention.

The wheel drive device 101 according to embodiment 2 is attached to, for example, a main body of the unmanned conveyance device, and constitutes a motor-equipped wheel of the unmanned conveyance device. The wheel drive apparatus 101 includes wheels 111, a motor 121, and a reduction mechanism 131.

The wheel 111 includes a tire portion 111c provided on an outer peripheral portion, a rim portion 111a to which the tire portion 111c is attached, and a wheel disc portion 111b supporting the rim portion 111 a. The tire portion 111c has elasticity, and its thickness becomes smaller with use. The wheel portion 111b is provided on the opposite side of the device from the motor so as to extend in the radial direction and is coupled to the reduction mechanism 131. The rim portion 111a has a tubular shape, and extends from the outer peripheral portion of the rim portion 111b toward the motor side in the axial direction.

The motor 121 includes a motor shaft 123 that rotates around a rotation axis O1, a rotor (not shown), a stator, a brake unit, and a housing 125, and the motor 121 drives the motor shaft 123 to rotate by electric power. The housing 125 is provided with a screw hole 125a connected to the main body of the unmanned conveying device. The screw hole 125a is provided in a flange portion 125f of the housing 125, which extends radially outward.

The reduction mechanism 131 is an eccentric oscillating type reduction gear, and includes an internal gear member 133, an external gear 135, an eccentric body 137, an eccentric body bearing 141, an internal pin 143, a carrier 145, a cover 149, a main bearing 151A, a main bearing 151B, an input bearing 153, and a counterweight 155.

The motor shaft 123, eccentric body 137, eccentric body bearing 141, external gear 135, internal pin 143, and counterweight 155 have the same configuration as the motor shaft 23, eccentric body 37, eccentric body bearing 41, external gear 35, internal pin 43, and counterweight 55 of embodiment 1. The inner pin hole 135a of the external gear 135 corresponds to the inner pin hole 35a of embodiment 1.

The internal gear body 133a and the plurality of outer pins 133b in the internal gear member 133 have the same structure as the internal gear body 33a and the outer pins 33b in embodiment 1. The inner tooth member 133 has holding

members

133c, 133d that hold a plurality of outer pins 133 b. The holding member 133c is coupled to the housing 125 of the motor 121 by a bolt or the like, whereby the internal gear member 133 is fixed.

The wheel carrier 145 is disposed on one side (opposite side to the motor) of the external gear 135 in the axial direction, and holds a plurality of internal pins 143. The wheel frame 145 has: a 1 st radially extending portion 145a extending radially outward from a portion of the retaining inner pin 143; and a 1 st axial extension 145b extending from the 1 st radial extension 145a toward the other side (motor side) in the axial direction. The 1 st radial extension 145a and the 1 st axial extension 145b are formed as separate members from each other and are coupled together by bolts or the like. The 1 st axial extension 145b is disposed radially outward of the internal tooth member 133. With regard to the wheel frame 145, for example, a part of the 1 st radially extending portion 145a is coupled with the disc portion 111b of the wheel 111 so as to rotate integrally with the wheel 111. The 1 st axial extension 145b corresponds to an example of the extension according to the present invention.

The

main bearings

151A, 151B are tapered roller bearings, for example, and are disposed between the 1 st axial extension 145B of the carrier 145 and the internal gear member 133. Accordingly, the carrier 145 is rotatably supported about the rotation axis O1 with respect to the internal gear member 133.

The input bearing 153 rotatably supports the motor shaft 123 on the side in the axial direction (the side opposite to the motor) of the external gear 135. The input bearing 153 is disposed between the housing 149 and the motor shaft 123. The cover 149 covers the motor shaft 123 and the input bearing 153 on the opposite side to the motor, and is coupled to the wheel frame 145 by bolts or the like.

< speed-reducing action >)

When the motor shaft 123 is rotated by driving the motor 121, the eccentric body 137 rotates to eccentrically oscillate the external gear 135. As the eccentric body 137 rotates, the counterweight 155 rotates, and a load in a direction opposite to a load generated by the eccentric oscillation of the external gear 135 is generated, thereby maintaining the rotational balance inside the reduction mechanism 131. When the external gear 135 eccentrically oscillates, the meshing position between the external teeth of the external gear 135 and the internal teeth of the internal gear member 133 changes in the circumferential direction. Since the internal gear member 133 is fixed to the housing 125 of the motor 121, the external gear 135 rotates (rotates) by an amount corresponding to the difference in the number of teeth (for example, 1 tooth) between the internal gear of the internal gear member 133 and the external gear 135 for every 1 rotation of the eccentric body 137.

The rotation component of the external gear 135 is output to the wheel frame 145 via the internal pin 143. As a result, the rotational movement of the motor 121 is decelerated at a reduction ratio of 1/(the number of teeth of the external gear 135) and then output to the wheel frame 145, so that the wheel 111 integrated with the wheel frame 145 is rotated. By the rotation of the wheels 111, the unmanned conveyance device travels on the traveling surface G0.

Extending structure of wheel frame

As described above, the wheel frame 145 has the 1 st radial extension 145a and the 1 st axial extension 145b. By adopting this structure, the following structure can be realized: the wheel carrier 145 holds the inner pin 143 inside the inner gear member 133, while the other part (1 st axial extension 145 b) of the wheel carrier is disposed radially outside the inner gear member 133.

According to such an extending structure of the carrier 145, the

main bearings

151A, 151B can be arranged between the internal gear member 133 and the 1 st axial extending portion 145B of the carrier 145. Further, the outer pin 133B of the internal gear member 133, the

main bearings

151A and 151B, the 1 st axial extension 145B of the wheel frame 145, and the outer peripheral portion of the wheel 111 can be arranged in this order in the radial direction.

As described above, the

main bearings

151A and 151B and the wheel 111 can be disposed radially outward of the outer pin 133B of the inner gear member 133, and therefore the

main bearings

151A and 151B can be disposed without increasing the axial dimension of the reduction mechanism 131. Although not particularly limited, as a preferable example, the

main bearings

151A, 151B are arranged such that both ends in the axial direction of the

main bearings

151A, 151B are located further inward than both ends in the axial direction of the tire portion 111c when viewed in the radial direction. Unlike the example of fig. 4, in the case where the input bearings are also provided on the motor side of the external gear 135, the

main bearings

151A and 151B may be disposed such that the axial ends of the

main bearings

151A and 151B are positioned further inside than the ends of the two input bearings 153. The two ends of the plurality of bearings are: the space portions of the plurality of bearings are also regarded as a part of the bearings, and the plurality of bearings are regarded as both ends when they are integrated.

Further, as a preferable example, although not particularly limited, the

main bearings

151A, 151B may be arranged so that at least a part of each main bearing overlaps the outer pin 133B when viewed in the radial direction. Further, as a preferable example, although not particularly limited, the two

main bearings

151A, 151B may be arranged so that at least a part of each main bearing overlaps the external gear 135 when viewed in the radial direction.

In addition, instead of the two

main bearings

151A, 151B, one main bearing (for example, a cross roller bearing or the like) may be used. In this case, as a preferable example, one main bearing may be disposed such that both ends in the axial direction of the one main bearing are located further inside than both ends in the axial direction of the tire portion 111 c. Further, as a preferable example, one main bearing may be arranged so that at least a part thereof overlaps the outer pin 133b when viewed in the radial direction. As a further preferable example, one main bearing may be arranged such that at least a part thereof overlaps with the external gear 135 when viewed in the radial direction.

In the example of fig. 4, a structure having one external gear 135 is shown, but a structure in which a plurality of external gears are arranged in an axial direction may be adopted. In this case, regarding whether or not the external gear overlaps the main bearing when viewed in the radial direction, it is sufficient to determine whether or not the main bearing overlaps the external gear when the plurality of external gears are regarded as one body (that is, when the space portions of the plurality of external gears are also regarded as a part of the external gears).

Relation between component integrated with internal tooth component and wheel

The internal gear member 133 is integrally coupled with the housing 125 of the motor 121. The case 125 is disposed such that a flange portion 125f of an outermost peripheral portion thereof overlaps with a tire portion 111c of the wheel 111 when viewed from the axial direction. In this way, since the outermost peripheral portion of the housing 125 protrudes radially outward to the position of the tire portion 111c, the axial dimension of the housing 125 can be shortened when the volume of the housing 125 is made constant as compared with a configuration in which the outermost peripheral portion is radially inward. Further, by using such a case 125, the axial dimension of the motor 121 can be shortened as compared with a motor that can obtain the same power, and further, the axial dimension of the wheel drive apparatus 101 can be shortened.

On the other hand, in the outermost peripheral portion of the housing 125 integrated with the internal gear member 133, a notch portion 125k having a distance L11 from the rotation axis O1 smaller than the outer radius L12 of the rim portion 111a of the wheel 111 is provided at least in a range facing the running surface G0. By the notch 125k, even when the thickness of the tire portion 111c decreases with use of the wheel 111, it is possible to avoid a part of the housing 125 from contacting the running surface G0 during the decrease of the tire portion 111 c. Like the plurality of notches 45k (see fig. 2 and 3) of the wheel carrier 45 of embodiment 1, a plurality of notches 125k may be provided at a plurality of positions in the circumferential direction.

Effect of the embodiments >

As described above, according to the wheel drive device 101 of embodiment 2, the wheel carrier 145 has the 1 st axial extension 145B arranged radially outward of the internal gear member 133, and the

main bearings

151A, 151B are arranged between the 1 st axial extension 145B and the internal gear member 133. The outer peripheral portion of the wheel 111 is disposed radially outward of the 1 st axial extension 145b. By adopting such an arrangement, the

main bearings

151A, 151B and the wheel 111 can be arranged so as to overlap the internal gear member 133 in the radial direction, and the axial dimension of the wheel drive apparatus 101 can be shortened.

Further, according to the wheel driving apparatus 101 of embodiment 2, the wheel frame 145 has: a 1 st radial extension 145a extending radially on one side of the external gear 135 in the axial direction; and a 1 st axial extension 145b extending axially from the 1 st radial extension 145 a. By adopting the above configuration, the above configuration can be realized in which the axial dimension is shortened, and a mechanism can be realized in which the wheel carrier 145 and the internal gear member 133 are rotatable relative to each other.

Further, according to the wheel drive device 101 of embodiment 2, the outermost peripheral portion of the housing 125 integrated with the internal gear member 133 is arranged so as to overlap the tire portion 111c of the wheel 111 when viewed from the axial direction. Therefore, the housing 125 can be made flat, so that the axial dimension of the motor 121 and, therefore, the axial dimension of the wheel drive device 101 can be shortened.

Further, according to the wheel drive device 101 of embodiment 2, the notch portion 125k is provided in the outermost peripheral portion of the housing 125 integrated with the internal gear member 133 at a portion facing the running surface G0. This can prevent a part of the housing 125 from contacting the running surface G0 during the process of reducing the tire portion 111 c. Further, since the notch portions 125k are provided at a plurality of positions in the circumferential direction, the degree of freedom of the mounting angle (circumferential angle) when the wheel drive device 101 is mounted on the main body of the unmanned conveyance device can be increased, and the workability of fixing and handling the wiring of the motor 121 can be improved.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. For example, the above embodiment shows an example in which a center crank type eccentric oscillating speed reducer is used as the speed reducing mechanism. However, as the speed reduction mechanism of the present invention, a so-called distributed eccentric oscillating type speed reduction device or a simple planetary speed reduction device in which two or more eccentric body shafts having eccentric bodies are arranged at positions offset from the axial center of the speed reduction device may be used. In the case of using a simple planetary reducer, the carrier becomes a constituent element synchronized with the revolution component of the external gear. In the above embodiment, the structure having two main bearings and one external gear is shown, but the main bearing may be one and may have a structure having a plurality of external gears.

In the above embodiment, the constituent elements integrally formed from a single member may be replaced with constituent elements formed by dividing the constituent elements into a plurality of members and connecting or fixing the members to each other. The constituent elements obtained by connecting a plurality of members may be replaced with constituent elements formed integrally from a single member. Further, the details specifically shown in the embodiments may be appropriately changed within a range not departing from the gist of the present invention.

Claims

1. A wheel drive device is provided with: an internal gear member having an internal gear; an external gear; a wheel carrier that is synchronized with a rotation component or a revolution component of the external gear; a main bearing disposed between the internal gear member and the wheel carrier; and a wheel that rotates integrally with the internal gear member, wherein the wheel driving device is characterized in that,

the wheel carrier has an extension arranged radially outward of the internal gear member,

the main bearing is disposed between the extension portion and the internal gear member,

the outer peripheral portion of the wheel is disposed radially outward of the extension portion,

the wheel carrier has: a 1 st radially extending portion that extends radially on one side of the external gear in the axial direction, i.e., the 1 st direction side; and a 1 st axial extension extending axially from the 1 st radial extension,

the 1 st axial extension constitutes the extension disposed radially outward of the internal tooth member,

the wheel that rotates integrally with the internal gear member has: a 2 nd radial extension portion extending in a radial direction on a side of the external gear opposite to the 1 st direction side; and a 2 nd axial extension portion extending in an axial direction from the 2 nd radial extension portion and disposed radially outward of the 1 st axial extension portion.

2. The wheel driving apparatus as claimed in claim 1, wherein,

the 1 st axial extension has a flange portion extending toward the radially outer side,

the flange portion is coupled to the 1 st radial extension.

3. The wheel drive apparatus according to claim 2, wherein,

the flange portion overlaps with a tire portion of the wheel as viewed in an axial direction.

4. The wheel driving apparatus as claimed in claim 1, wherein,

the outer peripheral surface of the 1 st axial extension is inclined with respect to the axial direction in a range opposed to the inner periphery of the corner portion between the 2 nd radial extension and the 2 nd axial extension.

5. The wheel driving apparatus as claimed in claim 1, wherein,

a distance from a rotation center axis of at least a portion of the outermost peripheral portion of the wheel frame, which portion is opposite to the wheel running surface, is smaller than an outer radius of a rim portion of the wheel.

6. The wheel driving apparatus as claimed in claim 5, wherein,

a plurality of portions of the outermost peripheral portion of the wheel frame in the circumferential direction from the rotational center axis are smaller than the outer radius of the rim portion.