Wheels, drive units, and moving devices

Abstract

To provide a wheel, a drive unit and a mobile device which can suppress interference between a holder of a bearing and a peripheral member.SOLUTION: A wheel includes a barrel holder 11, a barrel support shaft 12, a barrel 13 and a bearing. The barrel holder 11 is rotationally driven. The plurality of barrel support shafts 12 are arranged in an outer peripheral part of the barrel holder 11 so as to be inclined with respect to a rotation axial line of the barrel holder 11. The barrel 13 is a barrel-shaped rotating body. The barrel 13 is rotatably supported by each barrel support shaft 12, and an outer peripheral surface contacts a travel path surface following the rotation of the barrel holder 11. The bearing has a holder 24d. A groove 40 is formed in an axial direction range including a projection region on the inner side in a radial direction of at least the holder 24d on an outer peripheral surface of the barrel support shaft 12.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a wheel, a drive unit, and a moving device used for the wheels of a moving device.

Background Art

[0002] Mecanum wheels are known as wheels for moving devices. This wheel includes a plurality of barrels that are barrel-shaped rotors, and a barrel holder that rotatably supports the plurality of barrels on the outer periphery. The barrel holder is rotationally driven by a driving device such as a motor (see, for example, Patent Document 1).

[0003] The plurality of barrels are held on the outer periphery of the barrel holder in a state inclined with respect to the holder rotation axis of the barrel holder. The wheels are arranged at substantially the four corners of the moving device, and each wheel arranged at the four corners is independently controlled by a driving device. That is, the moving device can freely move in various directions by individually controlling the rotation direction and torque of each wheel. Note that the wheels arranged on the left and right of the moving device are set with the inclination directions of the barrels held on the outer periphery of the barrel holder being opposite.

[0004] In addition, a pair of support flanges that protrude radially outward are provided at both ends on the outer side in the axial direction of the barrel holder, and a plurality of barrel support shafts are fixed so as to straddle the pair of support flanges. Each barrel is rotatably supported by a corresponding barrel support shaft and barrel holder via a radial bearing and a thrust bearing.

[0005] The thrust bearing is arranged in a bearing housing portion surrounded by a circular recess formed at an end portion in the axial direction of the barrel and the outer peripheral surface of the barrel support shaft. The thrust bearing includes a first raceway plate that contacts a member on the bottom wall side of the recess of the barrel in the bearing housing portion, a second raceway plate that contacts a member on the support flange side of the barrel holder, and a plurality of rolling elements that are rotatably in contact with the first raceway plate and the second raceway plate. The plurality of rolling elements are rotatably supported by a cage and are arranged between the first raceway plate and the second raceway plate together with the cage. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Special Publication No. 2009-504465 [Overview of the project] [Problems that the invention aims to solve]

[0007] When the barrel holder is rotated by a drive device such as a motor, the outer surfaces of the multiple barrels on the barrel holder sequentially come into contact with the road surface, and the moving device is propelled by the reaction force from the road surface. At this time, the contact position of each barrel moves continuously between one end and the other end in the axial direction as the barrel holder rotates. Therefore, when the moving device is running, large thrust loads are alternately applied to the thrust bearings on one end and the other end in the axial direction of the barrel. At this time, in the thrust bearing on the side opposite to the side to which the large thrust load is applied, the thrust load decreases, which may cause the first and second raceway plates to move in a direction away from the rolling elements. If the distance between the first and second raceway plates relative to the rolling elements becomes large, the cage may be displaced radially together with the rolling elements, and there is a possibility that the cage may interfere with surrounding members such as the barrel support shaft.

[0008] One solution to this problem is to strictly control the gap between the first and second raceway plates of the thrust bearing and the mating member (for example, the barrel holder side member) that contacts them axially. However, this would significantly increase the manufacturing cost of the parts and impose a complicated process on the manufacturer to manage the gap.

[0009] The present invention provides a wheel, a drive unit, and a moving device that can suppress interference between the bearing cage and surrounding components without requiring strict clearance control between components. [Means for solving the problem]

[0010] A wheel according to one aspect of the present invention comprises a rotationally driven barrel holder, a plurality of barrel support shafts arranged on the outer circumference of the barrel holder so as to be inclined with the rotation axis of the barrel holder, a barrel which is a barrel-shaped rotating body rotatably supported on each of the barrel support shafts and whose outer surface contacts the road surface as the barrel holder rotates, and a bearing having a cage which is arranged around the barrel support shaft near the axially outer end of the barrel, wherein grooves are provided in the axial range of the outer surface of the barrel support shaft, including at least the projected area radially inward of the cage.

[0011] The bearing comprises a first raceway that contacts a member on the barrel side in the axial direction, a second raceway that contacts a member on the barrel holder side in the axial direction, a plurality of rolling elements disposed between the first and second raceway and rotatably contacting the first and second raceway, and a retainer disposed between the first and second raceway and supporting the plurality of rolling elements, wherein the groove may be provided in an axial range on the outer circumferential surface of the barrel support shaft that spans the ends of the mutually opposing surfaces of the first and second raceway.

[0012] Preferably, the groove is provided in an axial range on the outer circumferential surface of the barrel support shaft that does not straddle the ends of the end faces of the first and second raceway plates that are opposite to the rolling elements.

[0013] The axial end of the barrel is provided with a recess that is recessed inward in the axial direction, and the bearing is arranged in a bearing housing surrounded by the recess of the barrel and the outer circumferential surface of the barrel support shaft. A groove may be provided on the inner circumferential surface of the recess in an axial range that includes at least the projected area radially outward of the retainer.

[0014] A wheel according to another aspect of the present invention comprises a rotationally driven barrel holder, a plurality of barrel support shafts arranged on the outer circumference of the barrel holder so as to be inclined with the rotation axis of the barrel holder, a barrel which is a barrel-shaped rotating body rotatably supported on each of the barrel support shafts and whose outer surface contacts the road surface as the barrel holder rotates, and a bearing having a cage which is arranged around the barrel support shaft near the axially outer end of the barrel, wherein the axial end of the barrel is provided with a recess that is recessed inward in the axial direction, the bearing is arranged in a bearing housing surrounded by the recess of the barrel and the outer surface of the barrel support shaft, and a groove is provided in the axial range of the inner surface of the recess, including at least the projected area radially outward of the cage.

[0015] The bearing comprises a first raceway that axially contacts a member on the barrel side, a second raceway that axially contacts a member on the barrel holder side, a plurality of rolling elements disposed between the first and second raceway and rotatably contacting the first and second raceway, and a retainer disposed between the first and second raceway and supporting the plurality of rolling elements. A spacer block mounted on the outer circumferential surface of the barrel support shaft is disposed between the end face of the second raceway opposite to the rolling elements and the barrel holder, and an elastic member is disposed between the spacer block and the second raceway, contacting the spacer block, the end face of the second raceway opposite to the rolling elements, and the outer circumferential surface of the barrel support shaft.

[0016] A drive unit according to one aspect of the present invention comprises a wheel and a drive device for rotationally driving the wheel, wherein the wheel comprises a barrel holder that is rotationally driven, a plurality of barrel support shafts arranged on the outer circumference of the barrel holder so as to be inclined with the rotation axis of the barrel holder, a barrel which is a barrel-shaped rotating body rotatably supported on each of the barrel support shafts and whose outer surface contacts the road surface as the barrel holder rotates, and a bearing having a cage which is arranged around the barrel support shaft near the axially outer end of the barrel, wherein a groove is provided in the axial range of the outer surface of the barrel support shaft, including at least the projected area radially inward of the cage.

[0017] A drive unit according to another aspect of the present invention comprises a wheel and a drive device for rotationally driving the wheel, wherein the wheel comprises a barrel holder that is rotationally driven, a plurality of barrel support shafts arranged on the outer circumference of the barrel holder so as to be inclined with the rotation axis of the barrel holder, a barrel which is a barrel-shaped rotating body rotatably supported on each of the barrel support shafts and whose outer surface contacts the road surface as the barrel holder rotates, and a bearing which has a cage and is arranged around the barrel support shaft near the axial outer end of the barrel, wherein the axial end of the barrel is provided with a recess that is recessed inward in the axial direction, the bearing is arranged in a bearing housing surrounded by the recess of the barrel and the outer surface of the barrel support shaft, and a groove is provided in the axial range of the inner surface of the recess, including at least the projected area radially outward of the cage.

[0018] A mobile device according to one aspect of the present invention comprises a wheel, a drive device for rotationally driving the wheel, and a vehicle body on which the wheel and the drive device are supported, wherein the wheel comprises a barrel holder that is rotationally driven, a plurality of barrel support shafts arranged on the outer circumference of the barrel holder so as to be inclined with the rotation axis of the barrel holder, a barrel which is a barrel-shaped rotating body rotatably supported on each of the barrel support shafts and whose outer surface contacts the road surface as the barrel holder rotates, and a bearing which is arranged around the barrel support shaft near the axially outer end of the barrel and has a retainer, wherein a groove is provided on the outer circumference of the barrel support shaft in an axial range that includes at least the projected area radially inward of the retainer.

[0019] Another aspect of the present invention provides a mobile device comprising a wheel, a drive device for rotationally driving the wheel, and a vehicle body supporting the wheel and the drive device, wherein the wheel comprises a rotationally driven barrel holder, a plurality of barrel support shafts arranged on the outer circumference of the barrel holder so as to be inclined with the rotation axis of the barrel holder, a barrel which is a barrel-shaped rotating body rotatably supported on each of the barrel support shafts and whose outer surface contacts the road surface as the barrel holder rotates, and a bearing having a cage which is arranged around the barrel support shaft near the axially outer end of the barrel, wherein the axial end of the barrel is provided with a recess that is recessed inward in the axial direction, the bearing is arranged in a bearing housing surrounded by the recess of the barrel and the outer surface of the barrel support shaft, and a groove is provided in the axial range of the inner surface of the recess, including at least the projected area radially outward of the cage. [Effects of the Invention]

[0020] The wheel according to the above-described aspect is provided with a groove in an axial range including a projection region inside the cage in the radial direction on the outer peripheral surface of the barrel support shaft. Therefore, when the direction of the thrust load acting on the bearing alternates as the wheel rotates, it is possible to suppress the cage of the bearing from being displaced in the radial direction and interfering with the outer peripheral surface of the barrel support shaft. Therefore, when the wheel according to the above-described aspect is adopted, it is possible to suppress interference between the cage of the bearing and the surrounding members without requiring strict clearance management between the members.

[0021] Further, the wheel according to the above-described other aspect is provided with a groove in an axial range including at least a projection region outside the cage in the radial direction on the inner peripheral surface of the recess facing the bearing housing. Therefore, when the direction of the thrust load acting on the bearing alternates as the wheel rotates, it is possible to suppress the cage of the bearing from being displaced in the radial direction and interfering with the inner peripheral surface of the recess of the barrel. Therefore, when the wheel according to the above-described other aspect is adopted, it is possible to suppress interference between the cage of the bearing and the surrounding members without requiring strict clearance management between the members.

Brief Description of the Drawings

[0022] [Figure 1] Plan view of the moving device of the embodiment. [Figure 2] Perspective view of the wheel of the first embodiment. [Figure 3] Cross-sectional view corresponding to the III-III cross-section of FIG. 2 of the wheel of the first embodiment. [Figure 4] Cross-sectional view corresponding to the IV-IV cross-section of FIG. 2 of the wheel of the first embodiment. [Figure 5] Cross-sectional view similar to FIG. 4 of the wheel of the second embodiment.

Modes for Carrying Out the Invention

[0023] Next, each embodiment of the present invention will be described based on the drawings. In each of the embodiments described below, the same reference numerals are given to common parts, and overlapping descriptions will be omitted. The wheel 10 of each embodiment is used in a mobile device 1, for example, as shown in Figure 1. Figure 1 shows the mobile device 1 as viewed from above. In each embodiment, the wheels 10 are positioned on both the left and right sides of the front of the vehicle body 2 of the mobile device 1, and on both the left and right sides of the rear of the vehicle body 2, respectively. Each wheel 10 is independently driven by a drive unit 3 supported by the vehicle body 2. The drive unit 3 includes a motor 4 and a reduction gear 5 that reduces the rotation of the motor 4 and transmits it to the wheel 10. In this embodiment, the wheel 10 and the drive unit 3 that rotates the wheel 10 constitute a drive unit. Furthermore, the wheels 10 positioned on the left and right sides of the moving device 1 are set so that the inclination direction of the barrel 13, which is held on the outer circumference of the barrel holder 11 (described later), is in the opposite direction.

[0024] <First Embodiment> Figure 2 is a perspective view of the wheel 10 of the first embodiment, and Figure 3 is a cross-sectional view corresponding to the section III-III in Figure 2. Figure 4 is a cross-sectional view corresponding to the section IV-IV in Figure 2. Note that in Figure 3, the internal structure of the barrel holder 11 is shown in a simplified manner to avoid the complexity of illustrating the internal structure of the barrel 13, which will be described later. As shown in these figures, the wheel 10 comprises a substantially cylindrical barrel holder 11 that is rotationally driven by a drive unit 3 (see Figure 1), a plurality of barrel support shafts 12 supported on the outer circumference of the barrel holder 11, and barrels 13, which are barrel-shaped rotating bodies supported by each barrel support shaft 12. In Figure 2, only one set of barrel mounting parts, such as the barrel 13 and the barrel support shaft 12, is shown, and the other sets of barrels 13 and barrel mounting parts are not shown. Regarding the other sets of barrels 13 and barrel mounting parts, only the central axis L2 of the barrel support shaft 12 is shown in Figure 2.

[0025] The barrel holder 11 comprises a pair of support flanges 14 spaced apart in the axial direction (width direction of the vehicle body 2) and a connecting cylinder 15 that connects the pair of support flanges 14. The pair of support flanges 14 are formed in the shape of perforated discs and together with the connecting cylinder 15 form a continuous, substantially cylindrical shape. Inside the substantially cylindrical barrel holder 11 is the drive unit 3 (a reduction gear 5 and part of the motor 4) shown in Figure 1. The output section of the reduction gear 5 is connected, for example, to the support flanges 14 to transmit the rotation of the reduced motor 4 to the barrel holder 11. The axis of rotation of the barrel holder 11 when it rotates in response to the rotation of the motor 4 is referred to as the holder rotation axis L1.

[0026] The outer diameter of the connecting cylinder 15 is smaller than the outer diameter of the support flange 14. The axial ends of the barrel support shaft 12, which supports each barrel 13, are fixed, for example, by bolts 17 in fixing grooves 16 formed on the outer circumferential surface of each support flange 14. The barrel support shaft 12 is fixed to the pair of support flanges 14 so as to be inclined at a predetermined angle in one direction with respect to the holder rotation axis L1. In addition, a barrel receiving recess 18 is formed on the side edge of each support flange 14 on the connecting cylinder 15 side, which accommodates the axial end of the barrel 13 supported by the barrel support shaft 12. Each barrel receiving recess 18 is provided with an opposing wall 19 that faces the axial end face of the barrel 13. The opposing wall 19 is formed to be perpendicular to the central axis L2 of the barrel 13 that is housed in the barrel receiving recess 18.

[0027] Each barrel 13 supported by a barrel support shaft 12 comprises a metal barrel base material 20 with a barrel-shaped bulge in the axial central region, and a urethane surface material 21 fixed to the outer circumferential surface of the barrel base material 20 by adhesive or the like. An axial hole 22 extending along the axial direction is formed at the axial center of the barrel base material 20. The barrel support shaft 12 is inserted through the axial hole 22. Between the axial hole 22 of the barrel base material 20 and the barrel support shaft 12, a radial bearing 23 and a thrust bearing 24 are interposed to rotatably support the barrel 13 on the barrel support shaft 12. The radial bearing 23 and the thrust bearing 24 are located at the axial ends on both sides of the axial hole 22, respectively. The thrust bearing 24 is located adjacent to the radial bearing 23 in the axial outer position within the axial hole 22. The thrust bearing 24 is positioned around the barrel support shaft 12 near the axial outer end of the barrel 13 and receives the thrust load acting on the barrel 13.

[0028] A recess 30 is provided at the axially outer end of the barrel base material 20, which is recessed inward in the axial direction. The recess 30 is formed at the axially outer end of the shaft hole 22 of the barrel base material 20, with its inner diameter expanding in a stepped manner. The axial end of the barrel 13 faces the opposing wall 19 of the barrel holder 11 within the barrel receiving recess 18 of the barrel holder 11. The thrust bearing 24 is located in a bearing housing 31 surrounded by the recess 30 of the barrel 13 and the outer circumferential surface of the barrel support shaft 12.

[0029] The thrust bearing 24 comprises a first raceway 24a, a second raceway 24b, a plurality of rolling elements 24c (for example, spheres), and a cage 24d. The first raceway plate 24a and the second raceway plate 24b are formed in the shape of perforated discs and face each other axially within the recess 30 of the barrel 13. The first raceway plate 24a is positioned on the bottom wall side within the recess 30 of the barrel 13, and its outer end face abuts against the end face 25 facing axially outward within the recess 30. The barrel support shaft 12 is fitted into the central holes of the first raceway plate 24a and the second raceway plate 24b. The thrust bearing 24, including the first raceway plate 24a and the second raceway plate 24b, is positioned around the barrel support shaft 12 near the axially outward end of the barrel 13.

[0030] Multiple rolling elements 24c are arranged in an annular manner between the first raceway 24a and the second raceway 24b, and are in rolling contact with the mutually opposing inner end faces of the first raceway 24a and the second raceway 24b. The retainer 24d is an annular member positioned between the first raceway 24a and the second raceway 24b, and rotatably supports the multiple rolling elements 24c.

[0031] Furthermore, a cylindrical metal spacer block 35 is fitted onto the outer circumferential surface of the barrel support shaft 12 in the region axially outward from the thrust bearing 24 (second raceway 24b). The outer diameter of the spacer block 35 is set to be smaller than the inner diameter of the recess 30 on the barrel 13 side. A portion of the spacer block 35 is inserted into the recess 30 of the barrel 13 from the axial outside. One axial end face of the spacer block 35 abuts against the end face of the opposing wall 19 of the barrel holder 11, and the other axial end face of the spacer block 35 abuts against the outer end face of the second raceway 24b of the thrust bearing 24 (the end face opposite to the rolling element 24c).

[0032] An annular recess 36 is formed on the inner peripheral edge of the other axial end face of the spacer block 35, step-like indentation on the side separated from the second raceway 24b. The annular recess 36 is open radially inward from the side of the spacer block 35 facing the second raceway 24b in the axial direction. The bottom surface of the annular recess 36 is composed of a flat surface perpendicular to the axial direction of the spacer block 35. An annular elastic member 37 is housed in the annular recess 36. The elastic member 37 is composed of an O-ring made of, for example, rubber or elastic resin. The elastic member 37 is mounted on the outer peripheral surface of the barrel support shaft 12. The basic outer diameter of the elastic member 37 is set to be larger than the axial depth of the annular recess 36. When the barrel 13 and barrel support shaft 12 are assembled to the barrel holder 11 together with the thrust bearing 24 and spacer block 35, the elastic member 37 is sandwiched between the bottom surface of the annular recess 36 of the spacer block 35 (the surface facing the second raceway plate 24b) and the outer end surface of the second raceway plate 24b, and is elastically in close contact with the outer surface of the barrel support shaft 12. At this time, the elastic force of the elastic member 37 acts to press the second raceway plate 24b toward the first raceway plate 24a.

[0033] A groove 40 is formed on the outer circumferential surface of the barrel support shaft 12 in the portion facing the bearing housing portion 31 of the barrel 13, with the groove recessed radially inward. The groove 40 is formed on the outer circumferential surface of the barrel support shaft 12 with a constant width and constant depth. The groove 40 is formed in an axial range of the outer circumferential surface of the barrel support shaft 12 that includes at least the radially inward projection area of ​​the retainer 24d. More specifically, the groove 40 is formed in an axial range that spans the radially inward ends 24ai and 24bi of the inner end faces (faces facing each other) of the first raceway plate 24a and the second raceway plate 24b on the outer circumferential surface of the barrel support shaft 12, but does not span the radially inward ends 24ao and 24bo of the outer end faces (end faces opposite to the rolling elements 24c) of the first raceway plate 24a and the second raceway plate 24b. The depth d1 of the groove 40 formed in the barrel support shaft 12 is preferably 0.2 mm ≤ d1 < 0.5 mm.

[0034] Incidentally, the outer circumferential surface of the axial central region of the barrel support shaft 12 becomes the contact surface for the radial bearing 23, and the outer circumferential surface of the axial end region of the barrel support shaft 12 is precisely fastened and fixed to the barrel holder 11 (fixing groove 16 of the support flange 14). Furthermore, the outer circumferential surface of the axial central region of the barrel support shaft 12 and the outer circumferential surface of the axial end region of the barrel support shaft 12 have different required outer diameter dimensions. For this reason, the polishing of the outer circumferential surface of the axial central region of the barrel support shaft 12 and the polishing of the outer circumferential surface of the axial end region of the barrel support shaft 12 are performed in separate processes. The groove 40 formed in the barrel support shaft 12 also serves as a polishing groove to prevent the other polishing area from being polished when the outer circumferential surface of the central region of the barrel support shaft 12 is polished and when the outer circumferential surface of the end region of the barrel support shaft 12 is polished.

[0035] Furthermore, a groove 45 is formed on the inner circumferential surface of the recess 30 on the barrel 13 side, recessing radially outward. The groove 45 is formed on the inner circumferential surface of the recess 30 with a constant width and constant depth. The groove 45 is formed in an axial range of the inner circumferential surface of the recess 30 that includes at least the radially outward projection area of ​​the retainer 24d. The depth d2 of the groove 45 formed on the inner circumferential surface of the recess 30 is preferably 0.2 mm ≤ d2 < 0.5 mm, similar to the depth d1 of the groove 40.

[0036] As described above, in this embodiment, the wheel 10 has grooves 40 formed in an axial range on the outer circumferential surface of the barrel support shaft 12, including at least the projected area radially inward of the cage 24d of the thrust bearing 24. Therefore, even if the gap between the first raceway 24a and the second raceway 24b of the thrust bearing 24 widens and the cage 24d of the thrust bearing 24 is displaced radially inward, the grooves 40 can prevent the cage 24d from interfering with the outer circumferential surface of the barrel support shaft 12. Therefore, when the wheel 10 of this embodiment is adopted, interference between the cage 24d of the thrust bearing 24 and surrounding members can be suppressed without requiring strict clearance control between members. This makes it possible to simplify manufacturing while suppressing the generation of wear particles caused by the cage 24d interfering with surrounding members.

[0037] Furthermore, in this embodiment, the wheel 10 has grooves 40 formed in an axial range that spans the radially inward ends 24ai and 24bi of the mutually opposing surfaces of the first raceway 24a and the second raceway 24b on the outer circumferential surface of the barrel support shaft 12. Therefore, even if the cage 24d fluctuates slightly in the axial direction when the gap between the first raceway 24a and the second raceway 24b of the thrust bearing 24 widens, it is possible to reliably avoid interference between the cage 24d and the outer circumferential surface of the barrel support shaft 12.

[0038] Furthermore, in this embodiment, the groove 40 of the wheel 10 is formed in an axial range that does not straddle the radially inward ends 24ai and 24bi of the end faces of the first raceway 24a and the second raceway 24b opposite to the rolling elements 24c on the outer circumferential surface of the barrel support shaft 12. Therefore, the groove 40 does not interfere with the stable support of the first raceway 24a and the second raceway 24b by the barrel support shaft 12. Consequently, when this configuration is adopted, the occurrence of play in the thrust bearing 24 can be suppressed and the quietness of the wheel can be improved.

[0039] Furthermore, in this embodiment, the wheel 10 has a groove 45 formed in the axial region of the inner circumferential surface of the recess 30 on the barrel 13 side, which includes at least the projected area radially outward of the cage 24d. Therefore, even if the gap between the first raceway 24a and the second raceway 24b of the thrust bearing 24 widens and the cage 24d of the thrust bearing 24 is displaced radially outward, the groove 45 prevents the cage 24d from interfering with the inner circumferential surface of the recess 30.

[0040] In this embodiment, the wheel 10 has a groove 40 formed on the outer circumferential surface of the barrel support shaft 12 and a groove 45 formed on the inner circumferential surface of the recess 30 on the barrel 13 side. However, it is also possible to form a relief groove on only one side, either the outer circumferential surface of the barrel support shaft 12 or the inner circumferential surface of the recess 30 on the barrel 13 side. Therefore, even if a relief groove (groove 45) is formed only on the inner circumferential surface of the recess 30 on the barrel 13 side, interference between the cage 24d of the thrust bearing 24 and the inner circumferential surface of the recess 30 on the barrel 13 side can be suppressed without requiring strict clearance management between the components.

[0041] Furthermore, in this embodiment, the wheel 10 has an elastic member 37 positioned between the spacer block 35 and the second raceway 24b, which are arranged around the barrel support shaft 12. This elastic member 37 contacts the end faces of the spacer block 35 and the second raceway 24b, as well as the outer circumferential surface of the barrel support shaft 12. As a result, the elasticity of the elastic member 37 constantly presses the second raceway 24b toward the first raceway 24a, thereby suppressing the widening of the gap between the first raceway 24a and the second raceway 24b. Therefore, when this configuration is adopted, the displacement of the retainer 24d in the radial direction and interference with the outer circumferential surface of the barrel support shaft 12 or the inner circumferential surface of the recess 30 can be further suppressed.

[0042] Furthermore, in this configuration, the elastic member 37 contacts the end face of the spacer block 35 and the second raceway plate 24b and the outer circumferential surface of the barrel support shaft 12. As a result, the elastic member 37 can suppress the generation of contact noise between the second raceway plate 24b and the spacer block 35, and the elastic member 37 can prevent the spacer block 35 from rotating against the outer circumferential surface of the barrel support shaft 12 without the need for fastening members or the like. Therefore, when this configuration is adopted, the number of dedicated parts for preventing the spacer block 35 from rotating against the outer circumferential surface of the barrel support shaft 12 can be reduced.

[0043] <Second Embodiment> Figure 5 is a cross-sectional view of the wheel 110 of this embodiment, similar to that shown in Figure 4. The wheel 110 of this embodiment has a basic configuration that is almost the same as that of the first embodiment, but the configuration of the spacer block 135, which is arranged around the barrel support shaft 12 adjacent to the thrust bearing 24, is different. In the first embodiment, the spacer block 35 has an annular recess 36 with a rectangular cross-section formed on the inner peripheral edge of the end face facing the second raceway 24b. However, in this embodiment, the annular recess 136 of the spacer block 135 is composed of a tapered surface 136a whose inner diameter gradually increases toward the second raceway 24b. When the barrel 13 and the barrel support shaft 12 are assembled to the barrel holder 11 together with the thrust bearing 24 and the spacer block 135, the elastic member 37 is sandwiched between the tapered surface 136a of the annular recess 136 of the spacer block 135 and the outer end face of the second raceway 24b, and also elastically close to the outer peripheral surface of the barrel support shaft 12.

[0044] Since the wheel 110 of this embodiment has a basic configuration that is almost the same as that of the first embodiment, it can obtain the same effects as the first embodiment described above. However, in this embodiment, since the annular recess 136 of the spacer block 135 of the wheel 110 is formed by a tapered surface 136a, when the spacer block 135 is assembled together with the thrust bearing 24 to the barrel support shaft 12, the barrel 13, and the barrel holder 11, the elastic member 37 can be efficiently pressed against the outer circumferential surface of the barrel support shaft 12 and the second raceway plate 24b. Therefore, by adopting this configuration, the separation restriction of the second raceway board 24b from the first raceway board 24a and the circumference restriction of the spacer block 135 can be made more reliable.

[0045] It should be noted that the present invention is not limited to the embodiments described above, and various design modifications are possible without departing from the spirit of the invention. For example, in the above embodiment, an O-ring made of rubber or elastic resin is exemplified as the elastic member 37 housed in the annular recess 36 (136) of the spacer block 35 (135), but the elastic member 37 is not limited to an O-ring. The elastic member 37 may be C-shaped or other shapes as long as it can apply an elastic reaction force to the outer circumferential surface of the second raceway plate 24b and the barrel support shaft 12. Furthermore, in the embodiments disclosed herein, those composed of multiple objects may be integrated, and conversely, those composed of a single object may be divided into multiple objects. Whether or not they are integrated, the invention is only necessary to achieve its objective. [Explanation of Symbols]

[0046] 1...Moving device, 3...Drive device (drive unit), 10, 110...Wheel (drive unit), 11...Barrel holder, 12...Barrel support shaft, 13...Barrel, 24...Thrust bearing (bearing), 24a...First raceway plate, 24b...Second raceway plate, 24c...Rolling element, 24d...Cage, 30...Recess, 31...Bearing housing, 35, 135...Spacer block, 37...Elastic member, 40...Groove, 45...Groove

Claims

1. A barrel holder that is driven to rotate, Multiple barrel support shafts are arranged on the outer circumference of the barrel holder so as to be inclined with respect to the rotation axis of the barrel holder, A barrel is a barrel-shaped rotating body that is rotatably supported on each of the barrel support shafts, and whose outer surface contacts the road surface as the barrel holder rotates, The barrel is positioned around the barrel support shaft near the axially outer end of the barrel and comprises a bearing having a cage, A groove is provided on the outer circumferential surface of the barrel support shaft in an axial range that includes at least the projected area radially inward of the retainer. The aforementioned bearing is, A first raceway plate that contacts the barrel side member in the axial direction, A second raceway plate that contacts the member on the barrel holder side in the axial direction, A plurality of rolling elements are positioned between the first raceway and the second raceway and are in rotatable contact with the first raceway and the second raceway. The system comprises a retainer positioned between the first raceway and the second raceway and supporting a plurality of rolling elements, The groove is provided on the outer circumferential surface of the barrel support shaft in an axial range that spans the ends of the mutually opposing surfaces of the first raceway plate and the second raceway plate.

2. The wheel according to claim 1, wherein the groove is provided on the outer circumferential surface of the barrel support shaft in an axial range that does not straddle the ends of the end faces of the first and second raceway plates opposite to the rolling elements.

3. The axial end of the barrel is provided with a recess that is recessed inward in the axial direction. The bearing is positioned in a bearing housing surrounded by the recess of the barrel and the outer circumferential surface of the barrel support shaft. The wheel according to claim 1 or 2, wherein a groove is provided in the axial range of the inner circumferential surface of the recess, including at least the projected area radially outward of the retainer.

4. The aforementioned bearing is, A first raceway plate that contacts the barrel side member in the axial direction, A second raceway plate that contacts the member on the barrel holder side in the axial direction, A plurality of rolling elements are positioned between the first raceway and the second raceway and are in rotatable contact with the first raceway and the second raceway. The system comprises a retainer positioned between the first raceway and the second raceway and supporting a plurality of rolling elements, Between the end face of the second raceway plate opposite to the rolling element and the barrel holder, a spacer block is positioned which is mounted on the outer surface of the barrel support shaft. The wheel according to claim 1, wherein an elastic member is disposed between the spacer block and the second raceway plate, and the elastic member contacts the spacer block, the end face of the second raceway plate opposite to the rolling element, and the outer circumferential surface of the barrel support shaft.

5. The system comprises a wheel and a drive device for rotating the wheel, The aforementioned wheel is A barrel holder that is driven to rotate, Multiple barrel support shafts are arranged on the outer circumference of the barrel holder so as to be inclined with respect to the rotation axis of the barrel holder, A barrel is a barrel-shaped rotating body that is rotatably supported on each of the barrel support shafts, and whose outer surface contacts the road surface as the barrel holder rotates, The barrel is positioned around the barrel support shaft near the axially outer end of the barrel and comprises a bearing having a cage, A groove is provided on the outer circumferential surface of the barrel support shaft in an axial range that includes at least the projected area radially inward of the retainer. The aforementioned bearing is, A first raceway plate that contacts the barrel side member in the axial direction, A second raceway plate that contacts the member on the barrel holder side in the axial direction, A plurality of rolling elements are positioned between the first raceway and the second raceway and are in rotatable contact with the first raceway and the second raceway. The system comprises a retainer positioned between the first raceway and the second raceway and supporting a plurality of rolling elements, The groove is provided in the drive unit on the outer circumferential surface of the barrel support shaft in an axial range that spans the ends of the mutually opposing surfaces of the first raceway plate and the second raceway plate.

6. The vehicle comprises a wheel, a drive device for rotating the wheel, and a vehicle body on which the wheel and the drive device are supported. The aforementioned wheel is A barrel holder that is driven to rotate, Multiple barrel support shafts are arranged on the outer circumference of the barrel holder so as to be inclined with respect to the rotation axis of the barrel holder, A barrel is a barrel-shaped rotating body that is rotatably supported on each of the barrel support shafts, and whose outer surface contacts the road surface as the barrel holder rotates, The barrel is positioned around the barrel support shaft near the axially outer end of the barrel and comprises a bearing having a cage, A groove is provided on the outer circumferential surface of the barrel support shaft in an axial range that includes at least the projected area radially inward of the retainer. The aforementioned bearing is, A first raceway plate that contacts the barrel side member in the axial direction, A second raceway plate that contacts the member on the barrel holder side in the axial direction, A plurality of rolling elements are positioned between the first raceway and the second raceway and are in rotatable contact with the first raceway and the second raceway. The system comprises a retainer positioned between the first raceway and the second raceway and supporting a plurality of rolling elements, The groove is provided on the outer circumferential surface of the barrel support shaft in an axial range that spans the ends of the mutually opposing surfaces of the first raceway plate and the second raceway plate.

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