Omnidirectional wheel and work vehicle including the same

Abstract

To provide an omnidirectional wheel having a structure in which each member is simple and easy to assemble.SOLUTION: The omnidirectional wheel 1 includes a rotary shaft 2, a wheel member 4 provided around the rotary shaft 2, a plurality of brackets 5 arranged at intervals on an outer peripheral edge of the wheel member 4, a plurality of first rollers 6 rotatably supported on both sides of the brackets 5, and a plurality of second rollers 7 arranged between the first rollers 6 and rotatably supported on the brackets 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an omnidirectional wheel and a work vehicle equipped with the same. [Background technology]

[0002] 2. Description of the Related Art Conventionally, an omnidirectional wheel has been known, which is configured by arranging a plurality of rollers in the circumferential direction of the wheel, the rollers rotating in a lateral direction perpendicular to the straight-ahead direction of the vehicle.

[0003] For example, the wheel described in Patent Document 1 has large-diameter rollers and small-diameter rollers arranged alternately in the circumferential direction, with rotational axes that run roughly along the circumferential direction, and the outer peripheries of the small-diameter rollers are rotatably supported by support members that protrude from plates around the wheel hub. Each large-diameter roller has a core member (bearing) at the rotational axis position, and the large-diameter roller is supported by abutting the core member against the aforementioned support members and shaft members that extend from the adjacent small-diameter rollers on both sides.

[0004] Furthermore, the wheel described in Non-Patent Document 1 is an improved version of the wheel in Patent Document 1, with multiple frames arranged around the wheel hub, with each large diameter roller supported at the center of each frame in the circumferential direction of the wheel, and adjacent small diameter rollers supported on both sides of each frame.

[0005] Furthermore, the wheels described in Patent Documents 2 and 3 have multiple brackets arranged around the hub (or rim), with multiple large-diameter rollers and multiple small-diameter rollers arranged alternately in the circumferential direction of the wheel. The large-diameter rollers and small-diameter rollers are all divided into two halves, and brackets are respectively arranged between the halves of the large-diameter rollers and between the halves of the small-diameter rollers. In other words, each bracket supports one of the halves of the large-diameter rollers or one of the halves of the small-diameter rollers on both sides. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3421290 [Patent Document 2] Patent No. 5778740 [Patent Document 3] Patent No. 6339424 [Non-patent literature]

[0007] [Non-Patent Document 1] Smooth Omni Wheel (Φ55mm): Robot Shop / Robot Shop Specializing in Robot-related Products (vstone.co.jp)”, [online], December 18, 2023, Japan Patent Association, [Searched December 18, 2023], Internet <URL:https: / / www.vstone.co.jp / robotshop / index.php?main_page=product_info&products_id=4394> Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, omnidirectional wheels have a complex structure in which rollers of different diameters are arranged alternately around the circumference of the wheel, but there is also a need to simplify each component, reduce the number of parts, simplify the assembly process, and reduce costs.

[0009] The present invention has been made to solve the problems of the prior art, and has as its object to provide an omnidirectional wheel having a structure in which each member is simple and easy to assemble. [Means for solving the problem]

[0010] An omnidirectional wheel according to one embodiment of the present invention comprises a rotation axis, a wheel member arranged around the rotation axis, a plurality of brackets arranged at intervals on the outer periphery of the wheel member, a plurality of first rollers rotatably supported on both sides of the brackets, and a plurality of second rollers arranged between the first rollers and rotatably supported on the brackets.

[0011] Both ends of the second roller may be located inside the corresponding first roller and supported by the corresponding bracket.

[0012] The first rollers may be annular members fitted onto both sides of the bracket so as to be rotatable relative to the bracket.

[0013] The bracket may support at least four rollers, including the first roller and the second roller.

[0014] The second roller may have a pair of roller center shafts that protrude from both ends in a direction substantially along the outer circumferential edge, and the roller center shafts may be supported by the bracket.

[0015] The bracket may have recesses on both sides, and the roller central shaft may be fitted into the recesses so as to be relatively rotatable and supported by the bracket.

[0016] On the outer peripheral edge of the first roller, a plurality of first lugs may be arranged radially around the center line of the first roller in a direction along the outer peripheral edge, and on the outer peripheral edge of the second roller, second lugs may be arranged to extend circumferentially around the center line of the second roller in a direction along the outer peripheral edge.

[0017] A work vehicle according to one embodiment of the present invention includes the omnidirectional wheel and a vehicle body that rotatably supports the rotation shaft of the omnidirectional wheel. [Effects of the Invention]

[0018] According to the omnidirectional wheel of the present invention, each member is simple and can be assembled relatively easily. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of an omni-directional wheel. [Figure 2]FIG. 1 is an outer side view of an omni-directional wheel. [Figure 3] FIG. 1 is an inner side view of the omni-directional wheel. [Figure 4] FIG. 1 is a front view of an omnidirectional wheel. [Figure 5] FIG. 1 is a side cross-sectional view of an omnidirectional wheel. [Figure 6] FIG. 10 is a front cross-sectional view of the omnidirectional wheel when the stopper is released. [Figure 7] FIG. 10 is a front view of the omni-directional wheel showing the stopper in the stopper release position. [Figure 8] FIG. 10 is a front cross-sectional view of the omnidirectional wheel when the stopper is in operation. [Figure 9] FIG. 10 is a front view of the omni-directional wheel showing the stopper in the stopper engaging position. [Figure 10] FIG. 10 is a front cross-sectional view of the omnidirectional wheel when a stopper with a different configuration is in operation. [Figure 11] FIG. 1 is a perspective view of the omni-directional wheel with the stopper removed. [Figure 12] FIG. 10 is a perspective view of a wheel member with a unit roller assembly assembled thereto. [Figure 13] FIG. 10 is an exploded perspective view showing a state in which the first roller has been removed from a bracket attached to a wheel member. [Figure 14] FIG. 10 is a perspective view of the wheel member with the unit roller assembly and the second roller assembled thereto. [Figure 15] FIG. 10 is an outer side view of the wheel member with the unit roller assembly and the second roller assembled thereto. [Figure 16] 10 is an exploded perspective view showing a state in which a first roller and a second roller have been removed from a bracket attached to a wheel member. FIG. [Figure 17] FIG. 10 is an exploded side view showing a state in which the first roller and the second roller have been removed from the bracket attached to the wheel member. [Figure 18] 1 is a perspective view showing a state in which a tractor, which is an example of a work vehicle equipped with omnidirectional wheels, is making a pivot turn. [Figure 19] 1 is a side view of a tractor, which is an example of a work vehicle equipped with omnidirectional wheels. [Figure 20] 1 is a diagram showing a drive / steering system structure of a work vehicle according to a first embodiment. [Figure 21] FIG. 6 is a diagram showing a drive system structure of a work vehicle according to a second embodiment. [Figure 22] FIG. 10 is a perspective view of a rover according to a third embodiment, which is another example of a work vehicle equipped with omnidirectional wheels. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, preferred embodiments of the omnidirectional wheel 1 and work vehicles 100, 200 according to the present invention will be described with reference to the accompanying drawings. [First embodiment] FIG. 1 is a perspective view of the omnidirectional wheel 1. FIG. 2 is an outer side view of the omnidirectional wheel 1. FIG. 3 is an inner side view of the omnidirectional wheel 1. FIG. 4 is a front view of the omnidirectional wheel 1. FIG. 5 is a side cross-sectional view of the omnidirectional wheel 1. FIG. 6 is a front cross-sectional view of the omnidirectional wheel 1 when the stopper 10 is released. FIG. 7 is a front view of the omnidirectional wheel 1 showing the stopper 10 in the stopper release position P1. FIG. 8 is a front cross-sectional view of the omnidirectional wheel when the stopper is activated. FIG. 9 is a front view of the omnidirectional wheel 1 showing the stopper 10 in the stopper activation position P2. FIG. 10 is a front cross-sectional view of the omnidirectional wheel 1 when a stopper 10 with a different configuration is activated.

[0021] FIG. 11 is a perspective view of the omnidirectional wheel 1 with the stopper 10 removed, showing the assembled (disassembled) structure of the omnidirectional wheel 1. FIG. 12 is a perspective view of the wheel member 4 with the unit roller assembly R attached. FIG. 13 is an exploded perspective view showing the first roller 6 removed from the bracket 5 attached to the wheel member 4. FIG. 14 is a perspective view of the wheel member 4 with the unit roller assembly R and second roller 7 attached. FIG. 15 is an outer side view of the wheel member 4 with the unit roller assembly R and second roller 7 attached. FIG. 16 is an exploded perspective view showing the first roller 6 and second roller 7 removed from the bracket 5 attached to the wheel member 4. FIG. 17 is an exploded side view showing the first roller 6 and second roller 7 removed from the bracket 5 attached to the wheel member 4.

[0022] As a diagram showing a work vehicle equipped with omnidirectional wheels 1, Fig. 18 is a perspective view showing a work vehicle (tractor) 100 equipped with omnidirectional wheels 1 making a pivot turn. Fig. 19 is a side view of a work vehicle (tractor) 100 equipped with omnidirectional wheels 1. Fig. 20 is a diagram showing the drive / steering system structure of the work vehicle 100 of the first embodiment.

[0023] The omnidirectional wheel 1 has, as basic wheel components for being supported as a wheel on the work vehicle 100, a hub 2 as a rotation axis (also called a central axis or axle) and a wheel member 4 provided around the hub 2. In this embodiment, the wheel member 4 is provided rotatably around the hub 2 via a bearing 3.

[0024] Hereinafter, the omnidirectional wheel 1 and the work vehicle 100 will be described with the center line of the hub 2 and the wheel member 4 referred to as the "wheel axis center Xw." The direction K1 in which the wheel axis center Xw extends (the direction along the wheel axis center Xw) will also be referred to as the "wheel axis center direction K1" (see FIG. 1, etc.). As shown in FIG. 4, etc., the hub 2 protrudes from the wheel member 4 on one of the two ends of the hub 2 and the wheel member 4 in the wheel axis center direction K1. This protruding portion of the hub 2 is attached to a knuckle arm 102a supported by the body 101 of the work vehicle 100, so that one side K2 of the omnidirectional wheel 1 is referred to as the "wheel inner side," and the opposite side K3 in the wheel axis center direction K1 is referred to as the "wheel outer side."

[0025] The rotation direction of the wheel member 4 around the hub 2 (wheel axis Xw) is the rotation direction of the omnidirectional wheel 1 as a wheel. This rotation direction is the circumferential direction around the wheel axis Xw, and this circumferential line is referred to as the "wheel circumferential line Cw," and the rotation direction along the wheel circumferential line Cw is referred to as the "wheel rotation direction" (see FIG. 1, etc.).

[0026] Note that the "wheel circumferential line Cw" does not specify a diameter. In other words, it is sufficient to specify the direction of wheel rotation about the wheel axis Xw, and any circumferential line of any diameter about the wheel axis Xw can be the wheel circumferential line Cw. The same applies to the first roller circumferential line Cr1 of the first roller 6, the second roller circumferential line Cr2 of the second roller 7, and the roller circumferential lines Cr of the rollers 6 and 7, which will be described later.

[0027] The omnidirectional wheel 1 has multiple rollers 6, 7 that are rotatable in a direction different from the rotation direction (wheel rotation direction) on the outer periphery of the wheel member 4. The multiple rollers 6, 7 are arranged radially around the hub 2. Each of the multiple rollers 6, 7 has a rotation center line Xr (roller axis Xr1, Xr2) that runs along the circumferential direction around the hub 2 (wheel circumferential line Cw).

[0028] The multiple rollers 6, 7 include multiple first rollers 6 and multiple second rollers 7. The multiple first rollers 6 and multiple second rollers 7 have protrusions (lugs) 6a, 7a on their outer peripheries. As will be described in detail later, the first roller 6 has multiple lugs 6a arranged radially on the outer periphery of the first roller 6, and the second roller 7 has one flange-shaped lug 7a extending along the outer periphery of the second roller 7.

[0029] As shown in Figures 2, 3, 5, etc., the omnidirectional wheel 1 has a plurality of brackets 5 arranged at intervals on the outer periphery (outer periphery) of the wheel member 4. A plurality of first rollers 6 are rotatably supported in pairs on both sides (support portions 5a) of each bracket 5. Specifically, a plurality of second rollers 7 are rotatably supported on separate adjacent brackets 5. In other words, each of the plurality of second rollers 7 is not disposed between a pair of first rollers 6 supported on a common bracket 5, but is disposed between a first roller 6 supported on one side of one bracket 5 and a first roller 6 supported on one side of another bracket 5 adjacent to the one bracket 5.

[0030] As shown in FIGS. 7, 9, etc., the first roller 6 has a plurality of radially arranged lugs 6a, each pair of which is arranged point-symmetrically about the roller axis Xr1. Therefore, as shown in FIGS. 5, 7, 9, 15, etc., the maximum diameter L1 of the first roller 6 is the diameter connecting the tips of the pair of lugs 6a arranged point-symmetrically, the farthest from the roller axis Xr1. On the other hand, as shown in FIGS. 5, 15, etc., the maximum diameter L2 of the second roller 7 is the diameter of the outer circumferential end of the flange-shaped lug 7a centered on the roller axis Xr2. As can be seen in FIGS. 5, 15, etc., the maximum diameter L1 of the first roller 6 is greater than the maximum diameter L2 of the second roller 7 (L1 > L2). For this reason, hereinafter, the first roller 6 may be referred to as the large-diameter roller, and the second roller 7 may be referred to as the small-diameter roller.

[0031] The brackets 5 are provided to protrude radially from the outer peripheral surface (outer peripheral edge) of the wheel member 4, centered on the wheel axis Xw, i.e., at intervals in the wheel rotation direction (direction along the wheel circumferential line Cw). The intervals between the brackets 5 are uniform, and the brackets 5 are arranged at equal intervals on the outer peripheral surface of the wheel member 4.

[0032] A pair of first rollers 6 is supported by each bracket 5, and the second rollers 7 are disposed in the gaps between the first rollers 6. Therefore, the multiple brackets 5, the multiple first rollers 6, and the multiple second rollers 7 are arranged along the outer circumferential direction of the wheel member 4 (the wheel rotation direction along the wheel circumferential line Cw).

[0033] A pair of second rollers 7 is supported by each bracket 5, and each bracket 5 supports four rollers 6, 7 including a first roller 6 and a second roller 7. However, it is sufficient that each bracket 5 supports at least four rollers 6, 7 including a first roller 6 and a second roller 7, and the number is not limited to four.

[0034] As shown in Figure 15 etc., the axis Xr1 of each first roller 6 and the axis Xr2 of the second roller 7 are aligned substantially along the wheel circumference Cw. Hereinafter, the axis Xr1 of each first roller 6 will be referred to as the "first roller axis Xr1." The direction along the first roller axis Xr1 will also be referred to as the "first roller axis direction." The axis Xr2 of each second roller 7 will also be referred to as the "second roller axis Xr2," and the direction along the second roller axis Xr2 will also be referred to as the "second roller axis direction."

[0035] Furthermore, the axis of rollers 6 and 7, which is the combination of the first roller axis Xr1 and the second roller axis Xr2, is referred to as the "roller axis Xr" (see Figures 6 to 9, 12, 15, etc.), and the direction along the roller axis Xr is sometimes referred to as the "roller axis direction."

[0036] The first roller 6 rotates in a direction along a circumferential line centered on the first roller axis Xr1. This circumferential line is perpendicular to the wheel circumferential line Cw, and this circumferential line is referred to as the "first roller circumferential line Cr1," and the direction of rotation along the first roller circumferential line Cr1 is referred to as the "first roller rotation direction" (see FIG. 12, etc.).

[0037] The second roller 7 rotates along a circumferential line centered on the second roller axis Xr2. This circumferential line is also perpendicular to the circumferential line defining the wheel rotation direction Cw, and this circumferential line is referred to as the "second roller circumferential line Cr2," and the rotation direction along the second roller circumferential line Cr2 is referred to as the "second roller rotation direction" (see Figure 14, etc.).

[0038] Furthermore, the circumferential line of rollers 6 and 7 formed by combining the first roller circumferential line Cr1 and the second roller circumferential line Cr2 is referred to as the "roller circumferential line Cr," and the direction of rotation of rollers 6 and 7 along the roller circumferential line Cr is sometimes referred to as the "roller rotation direction" (see Figures 1, 6 to 9, etc.).

[0039] A plurality of grooves 4a extending along the wheel axis direction K1 are formed on the outer peripheral surface of the wheel member 4. The base end of each bracket 5 is fitted into each groove 4a, and the bracket 5 is attached to the wheel member 4. As a result, the same number of brackets 5 as the grooves 4a are radially protruded from the wheel member 4 as described above (see FIG. 5, etc.). The plurality of grooves 4a are formed at equal intervals in the circumferential direction of the wheel member 4.

[0040] As can be seen in Figure 12, when viewed in a direction perpendicular to the wheel axis direction K1, the outer surface of the wheel member 4 is an arc-shaped curved surface that narrows toward the center line at the middle part in the wheel axis direction K1.

[0041] As shown in Figures 3, 4, 6 to 9, 12 to 14, 16, etc., a flange 4b ​​is provided at the wheel-inside K2 end of the wheel member 4. As shown in Figures 3, 4, 6 to 9, a flange 2a is also formed on the hub 2. The wheel-inside K2 end face of the flange 4b ​​of the wheel member 4 abuts against the wheel-outside K3 end face of the flange 2a of the hub 2. In addition, the wheel-inside K2 end of the bracket 5 attached to the wheel member 4 abuts against the wheel-outside K3 end face of the flange 4b ​​of the wheel member 4. The bracket 5 is locked to the hub 2 by fastening the flange 2a and the bracket 5 together via the flange 4b ​​with a fastening member (for example, a bolt).

[0042] Additionally, a stay portion 5d (see FIGS. 5 and 17) formed at the end of the bracket 5 on the wheel inner side K2 abuts against the end face of the wheel outer side K3 of the flange 4b ​​of the wheel member 4. The stay portion 5d is fastened to the flange 4b ​​with a fastening member (e.g., a bolt), thereby fixing the bracket 5 to the wheel member 4. This prevents the flange 4b ​​of the wheel member 4 from falling off the wheel inner side K2 of the bracket 5 from the wheel member 4.

[0043] On the other hand, the end face of the outer wheel side K3 of the bracket 5 attached to the wheel member 4 is flush with the outer wheel end face 4c (see Figures 6 to 9, 12 to 14, etc.) of the wheel member 4. As shown in Figures 6 to 9, etc., a wheel cover plate 9 abuts against the outer wheel end face 4c of the wheel member 4, and the bracket 5 and the wheel cover plate 9 are fixed with fixing members (for example, screws).

[0044] As shown in Figures 6, 8, etc., the tip of each bracket 5 attached to the wheel member 4 is arranged so as to describe an arc corresponding to the outer peripheral shape of the first roller 6. As shown in Figures 16 and 17, on both sides (in the axial direction of the first roller) of the tip of the bracket 5 arranged in such an arc shape, a disk-shaped support portion 5a corresponding to the inner diameter of the first roller 6 is protruded.

[0045] 13, 16, etc., the first roller 6 is an annular member. The first roller 6 is fitted onto both sides of the bracket 5 so as to be rotatable relative to the bracket 5. More specifically, as shown in FIG. 5, etc., the inner peripheral surface of the first roller 6 is in sliding contact with the outer peripheral surface of the support portion 5a, so that the first roller 6 is fitted onto the support portion 5a so as to be rotatable relative to the bracket 5.

[0046] When the first roller 6 is viewed from the first roller axial direction, the multiple lugs (first lugs) 6a protrude radially from the center line along the first roller axial direction relative to the outer circumferential surface of the first roller 6. The multiple lugs 6a are arranged at regular intervals (i.e., at equal intervals) along the outer periphery of the first roller 6. In other words, the outer circumferential surface of the first roller 6 extends between two adjacent lugs 6a, that is, a gap 6s is formed between the lugs 6a on the outer circumferential surface.

[0047] As described above, each bracket 5 supports a pair of first rollers 6 at the support portions 5a on both sides thereof. Hereinafter, a combination of one bracket 5 and the pair of first rollers 6 supported by the support portions 5a on both sides thereof will be referred to as a unit roller assembly R (see Figures 2, 3, etc.).

[0048] For the moment, of the two ends of the first roller 6 in the first roller axial direction, the end closest to the other first roller 6 included in the common roller assembly R will be referred to as the first end, and the other end on the opposite side as the second end. In this case, as can be seen from Figures 5 and 15, strictly speaking, the multiple lugs 6a of the first roller 6 are tapered as they move from the first end to the second end. Therefore, for the first roller 6, strictly speaking, the first end in the first roller axial direction, including the diameters of the multiple lugs 6a, is the maximum diameter portion of the first roller 6 having the aforementioned maximum diameter L1.

[0049] However, there is only a slight difference in diameter between the first end and the second end of the lug 6a of the first roller 6 in the first roller axial direction. Therefore, the multiple lugs 6a of the first roller 6 may have a substantially uniform diameter L1 over the entire length in the first roller axial direction. In other words, the entire area between both ends of the first roller 6 in the first roller axial direction may be a maximum diameter portion having substantially the maximum diameter L1.

[0050] As shown in Figure 5 etc., each second roller 7 is disposed between adjacent unit roller assemblies R (between the first roller 6 of one unit roller assembly R and the first roller 6 of the other unit roller assembly R). Both ends of the second roller 7 are located inside the corresponding first roller 6 and are supported by the corresponding brackets 5.

[0051] When the second roller 7 positioned in this position is viewed along the wheel axis Xw, the end of the second roller 7 on the first roller 6 side is located inside the first roller 6 and overlaps with the first roller 6. The second roller 7 has a barrel-shaped intermediate portion 7a in the axial direction of the second roller that is thick in the radial direction. The intermediate portion 7a, which is the largest diameter portion of the second roller 7 having a maximum diameter L2, forms the aforementioned lug (second lug) 7a that protrudes circumferentially around the second roller axis Xr2 along the outer periphery, i.e., in the shape of a flange. Hereinafter, the flange-shaped intermediate portion 7a and lug 7a may be interchangeably referred to as "lug."

[0052] As shown in Fig. 5 and other figures, the second rollers 7 have shaft members 8 that serve as rotational shafts. In other words, the second rollers 7 are provided around each shaft member 8. As shown in Fig. 14 and other figures, a bushing 8b is interposed between the shaft member 8 and the second rollers 7, allowing the second rollers 7 to rotate freely relative to the shaft member 8.

[0053] The second roller 7 has tapered end portions 7b (hereinafter referred to as "tapered end portions") on both sides in the axial direction of the second roller. The tapered end portions 7b have a smaller diameter than the intermediate portion 7a. The diameter of the tapered end portions 7b is set according to the inner diameter of the first roller 6.

[0054] 5, 17, etc., both ends of the shaft member 8 protrude as roller central shafts 8a from the center of the tapered end portions 7b on both sides in the second roller axial direction of the second roller 7. That is, the second roller 7 has a pair of roller central shafts 8a protruding from both ends in the direction along the outer circumferential edge.

[0055] 5, 7, 9, 12, 13, 16, 17, etc., an inclined notch 5b is formed in each support portion 5a of the bracket 5. The notch 5b is recessed from the side farther from the wheel member 4 to the side closer to the wheel member 4. The portion of the tapered end 7b of the second roller 7 that is closer to the wheel member 4 is placed in the internal space of the support portion 5a formed by this notch 5b.

[0056] 5, 14, 15, etc., the majority of the tapered end 7b of the second roller 7 is disposed in the inner space surrounded by the inner circumferential surface of the annular first roller 6 provided around the support portion 5a. On the other hand, the portion of the tapered end 7b of the second roller 7 that is farthest from the wheel member 4 protrudes outward from the inner space of the first roller 6.

[0057] Furthermore, as shown in Figures 5, 7, 9, 12, 13, 16, 17, etc., recesses 5c are formed on both sides (support portions 5a) of the bracket 5. The recesses 5c are shaft holes in the inclined surfaces that form the notches 5b that correspond to the roller central shaft 8a, which is the end of the shaft member 8 that protrudes from the tapered end portion 7b of the second roller 7. The roller central shaft 8a that protrudes from the tapered end portion 7b and is fitted into the notches 5b is fitted (inserted) into the recesses 5c so as to be relatively rotatable, and is supported by the support portions 5a.

[0058] As a result, both ends (narrowed ends 7b) of each second roller 7 are disposed inside the corresponding first roller 6 and are supported by the corresponding brackets 5.

[0059] In this way, in the omnidirectional wheel 1, each bracket 5 supports four rollers 6, 7, including a pair of first rollers 6 and a pair of second rollers 7, at support portions 5a on both sides in the roller axial direction (wheel rotation direction).

[0060] As described above, in this embodiment, the tapered end 7b of the second roller 7 is supported by (the support portion 5a, etc. of) the bracket 5. Therefore, the second roller 7 is not supported by the first roller 6. As a result, the first roller 6 does not require support strength to support the second roller 7, and the dimension of the first roller in the axial direction can be made relatively small. In other words, the dimension of the support portion 5a in the axial direction of the first roller can also be made relatively small accordingly.

[0061] In this way, by reducing the dimensions of the first roller 6 and the support portion 5a in the first roller axis direction, the width of the unit roller assembly R in the first roller axis direction is reduced, and accordingly the length in the second roller axis direction of the second roller 7 (i.e., the axial length of the shaft core member 8) arranged in the gap between the unit roller assemblies R is increased. Therefore, the maximum diameter (maximum diameter L2) of the barrel-shaped second roller 7 at the intermediate portion 7a (lug 7a) in the second roller axis direction is also increased.

[0062] The second roller 7 rotates around the axle member 8 to facilitate smooth movement of the omnidirectional wheel 1 when the wheel 1 moves in the wheel axis direction K1 while remaining in contact with the ground. By increasing the diameter (maximum diameter L2) of the middle portion 7a (lug 7a) of the second roller 7, which is the largest diameter portion of the second roller 7, as described above, even when the omnidirectional wheel 1 moves in the wheel axis direction K1 on relatively soft soil, a portion of the second roller 7 can protrude even slightly from the soil, allowing the wheel 1 to traverse the soil.

[0063] Furthermore, as shown in Figures 1, 2, 6 to 9, 11, etc., the omnidirectional wheel 1 is provided with a stopper 10 for preventing rotation of at least one of the rollers 6, 7. The stopper 10 provided on the omnidirectional wheel 1 and the roller structure of the omnidirectional wheel 1 corresponding to the stopper 10 will be described below.

[0064] First, at least one of the rollers 6, 7 of the omnidirectional wheel 1 has a hook that can come into contact with the stopper 10. That is, in the omnidirectional wheel 1 according to this embodiment, the stopper 10 does not have a surface that presses against the outer periphery of the roller, but the roller has a hook that can come into contact with the stopper 10. Therefore, the stopper 10 itself is not a complex structure such as a brake shoe with an arc-shaped surface, but can be constructed from a simple member such as a disk-shaped member described below.

[0065] Furthermore, the hooking portion of this roller restrains at least one of the rotations of the roller on one side and the other side by abutting against stopper 10. In other words, the hooking portion only needs to restrain rotation on one side of the roller's bidirectional rotation by abutting against stopper 10. Therefore, even if the area of ​​the hooking portion of the roller that abuts against stopper 10 is relatively small, it can sufficiently restrain rotation on that side of the roller.

[0066] The hooking portion of such a roller may be, for example, a groove formed in the outer peripheral surface of the roller, with the side walls on both sides of the groove serving as the hooking portion. Alternatively, the hooking portion may be a plurality of protrusions that protrude from the outer peripheral surface of the roller and can come into contact with stopper 10 on one side and the other side in the rotation direction of the roller.

[0067] In the omnidirectional wheel 1 according to this embodiment, the multiple lugs 6a (lugs 6a1 and 6a2 described below) of the first roller 6, which are provided to increase traction on soft ground, protrude from the outer circumferential surface of the first roller 6 and correspond to multiple protrusions that can come into contact with stoppers 10 on one side and the other side in the rotation direction of the first roller 6 (the first roller rotation direction along the first roller circumferential line Cr1). That is, each lug 6a of the first roller 6 is a hook that can come into contact with the stopper 10, and by each lug 6a coming into contact with the stopper 10 as the hook, at least one of the rotations of the first roller 6 on one side and the other side is suppressed.

[0068] The stopper 10 is a disk-shaped member that can enter the gap 6s between two adjacent lugs (protrusions) 6a (6a1, 6a2) of the first roller 6. That is, when the outer peripheral edge of the stopper 10, which is a disk-shaped member, enters the gap 6s between the lug 6a1 and the lug 6a2 of each first roller 6, the two lugs 6a1 and 6a2 that sandwich the gap 6s are disposed on one side and the other side of the outer peripheral edge of the stopper 10 in the rotation direction of the first roller 6. In this state, regardless of the direction (counterclockwise or clockwise) in which the first roller 6 rotates around the first roller axis Xr1, the outer peripheral edge of the stopper 10 abuts against either the lug 6a1 on one side of the rotation direction or the lug 6a2 on the other side, thereby preventing further rotation of the first roller 6 in that rotation direction. That is, the outer peripheral edge of the stopper 10 that enters the gap 6s restricts the rotation of the first roller 6.

[0069] As shown in Figures 6 and 7, the stopper 10 can be switched between a stopper release position (roller rotation allowance position, first position) P1 in which it does not abut against the lugs 6a (6a1, 6a2) of the first roller 6, which are protruding portions, thereby allowing the first roller 6 to rotate, and a stopper action position (roller rotation restriction position, second position) P2 in which it abuts against the lugs 6a (6a1, 6a2) of the first roller 6, which are protruding portions, thereby restricting the rotation of the first roller 6, as shown in Figures 8 and 9.

[0070] The outer peripheral edge of the stopper 10 at the stopper release position P1 is not located in the gap 6s between adjacent lugs 6a (lug 6a1 and lug 6a2), and the outer peripheral edge of the stopper 10 at the stopper action position P2 is located in the gap 6s between adjacent lugs 6a (lug 6a1 and lug 6a2).

[0071] The stopper 10 can be switched between a stopper release position P1 and a stopper activation position P2 by moving forward and backward in the wheel axis direction K1, which is the direction along the rotation axis (hub 2) of the omnidirectional wheel 1. Specifically, the stopper 10 in the stopper release position P1 is switched to the stopper activation position P2 by moving forward toward the wheel inner side K2 toward the omnidirectional wheel 1. On the other hand, the stopper 10 in the stopper activation position P2 is switched to the stopper release position P1 by moving backward from the omnidirectional wheel 1 toward the wheel outer side K3.

[0072] The outer peripheral edge of the stopper 10 at the stopper action position P2 comes into contact with the lug 6a, which is a protrusion on the first roller 6, and restricts the rotation of the first roller 6. As described above, the outer peripheral edge of the stopper 10, which is disposed at the stopper action position P2 by moving back and forth in the wheel axis direction K1, simultaneously enters the gaps 6s between the lugs 6a of all the first rollers 6 of the omnidirectional wheel 1, and restricts the rotation of all the first rollers 6 at once.

[0073] If the length of the gap 6s in the rotation direction of the first roller 6 is relatively tight, two lugs 6a will simultaneously abut on the outer peripheral edge of the stopper 10 on one and the other sides in the rotation direction of the first roller when the stopper 10 enters the gap 6s. In this way, if the design does not allow for a relatively tight gap 6s between the lugs 6a of the first roller 6, the stopper 10 in the stopper action position P2 will fix all of the first rollers 6 without allowing them to rotate at all in either direction in the rotation direction. In other words, this means that there is no play area in the gap 6s for the rotation of the first rollers 6.

[0074] On the other hand, if the gap 6s has a certain length in the rotation direction of the first roller 6, the first roller 6 can rotate from a rotation position where one lug 6a (e.g., 6a1) across the gap 6s abuts against the stopper 10 to a rotation position where the other lug 6a (e.g., 6a2) abuts against the stopper 10 without abutting against the stopper 10. That is, in this case, a play area that allows the rotation of the first roller 6 is provided in the gap 6s.

[0075] As mentioned above, the concept that the stopper 10 at the stopper action position P2 "restricts" the rotation of the first roller 6 includes a state in which there is no play area in the gap 6s where the outer edge of the stopper 10 enters, and the stopper 10 does not allow the first roller 6 to rotate at all, and a state in which the stopper 10 allows the first roller 6 to rotate only within the range in which there is a play area in the gap 6s.

[0076] Here, the multiple rollers 6, 7 of the omnidirectional wheel 1 include a second roller 7 in addition to the first roller 6. The second roller 7 has a different shape from the first roller 6. Specifically, as described above, the first roller 6 is a large-diameter roller and the second roller 7 is a small-diameter roller. Furthermore, the first roller 6 has multiple lugs 6a that protrude radially from its outer periphery, while the second roller 7 has a single flange-shaped lug 7a. The second roller 7 is disposed between at least two first rollers 6 along the outer periphery of the wheel member 4, centered on the wheel axis Xw, which is the rotation axis (hub 2) of the omnidirectional wheel 1.

[0077] For these multiple rollers 6, 7, the stopper 10 can enter the gap 6s between two adjacent protrusions (lugs 6a) of the first roller 6. The outer peripheral edge of the stopper 10 comes into contact with the protrusions (lugs 6a) and restricts the rotation of the first roller 6. In other words, compared to the second roller 7, the first roller 6, which is a large-diameter roller having multiple protrusions (lugs 6a), can more easily utilize the lugs 6a as hooks that can come into contact with the stopper 10 on one side and the other side of the rotation direction of the roller, and can more easily cooperate with the stopper 10.

[0078] 2, 3, 5, etc., the rollers 6, 7 of the omnidirectional wheel 1 include two first rollers 6 that are arranged symmetrically about the wheel axis Xw, which is the rotation axis (hub 2) of the omnidirectional wheel 1. As shown in FIGS. 2, 3, 6 to 9, etc., the diameter L4 of the stopper 10 is shorter than the distance L3 between the first roller axis Xr1, which is the rotation center line of the two first rollers 6 that are arranged symmetrically about that point (L3>L4).

[0079] As shown in Fig. 7, among the plurality of lugs 6a and gaps 6s of each first roller 6, two lugs 6a1, 6a2 and the gap 6s between the lugs 6a1, 6a2 are closest to the outer peripheral edge of the stopper 10 at the first position P1. Here, in each first roller 6, the lugs 6a1, 6a2 and the gap 6s between the lugs 6a1, 6a2 are on the side closer to the wheel axle center Xw of the wheel 1 in all directions than the first roller axle center Xr1, that is, on the side of the first roller 6 facing the outer peripheral surface of the wheel member 4, and are located closer to the wheel outer side K3 than the center position of the first roller 6 in the wheel axle direction K1. Therefore, with respect to the outer peripheral edge of the stopper 10 having a diameter L4 shorter than the distance L3 as described above, among the plurality of lugs 6a and gaps 6s of each first roller 6, the lugs 6a1, 6a2 and the gap 6s between the lugs 6a1, 6a2 are the closest.

[0080] With such a configuration, as soon as the stopper 10 at the stopper release position P1 moves to the wheel inner side K2 and reaches the stopper action position P2, as shown in Fig. 9, the outer peripheral edge of the stopper 10 enters the gap 6s between the lugs 6a1, 6a2.

[0081] Here, when the stopper 10 is at the stopper action position P2, in order to restrict the rotation of the first roller 6, only the outer peripheral edge that has entered the gap 6s is involved in the cooperation for the stopper 10. On the other hand, in the first roller 6, among the plurality of lugs 6a, only two lugs 6a1, 6a2 on one side and the other side in the first roller rotation direction that contact (or can contact) the outer peripheral edge of the stopper 10 that has entered the gap 6s are involved.

[0082] Therefore, for the stopper 10, in order to restrict the rotation of the first roller 6, the outer peripheral edge may be arranged at a position where it can contact the lugs 6a1, 6a2 on the wheel axle center Xw side of the first roller axle center Xr1 in the radial direction from the wheel axle center Xw. Thereby, the diameter L4 of the stopper 10 can be made shorter (L4 < L3) as described above, and the stopper 10 can be miniaturized.

[0083] On the other hand, for the first roller 6, of the multiple lugs 6a, only two, 6a1 and 6a2, may come into contact with the stopper 10 when the stopper 10 is operating. This reduces the load on the first roller 6 as a whole, improving durability. More specifically, the lugs 6a of each first roller 6 that become lugs 6a1 and 6a2 when the stopper 10 is operating are those that happen to be in the appropriate positions in the rotational direction of the first roller 6 at that time. It is not the case that specific lugs 6a always become lugs 6a1 and 6a2. In other words, it is highly likely that different first lugs 6a become lugs 6a1 and 6a2 each time the stopper 10 operates on the omnidirectional wheel 1. Therefore, the load on the first roller 6 due to the stopper 10 is reduced, improving durability of the first roller 6.

[0084] Furthermore, when the first roller 6 attempts to rotate toward one side in the first roller rotation direction and comes into contact with the lug 6a1 or 6a2, the outer peripheral edge of the stopper 10 at the stopper action position P2 applies a surface pressure to the lug 6a1 or 6a2 so that they face each other in the first roller rotation direction. In other words, even if the lug 6a1 or 6a2 attempts to rotate, the outer peripheral edge of the stopper 10 acts as a barrier and catches the lug 6a1 or 6a2. In this case, even if the contact area between the stopper 10 and the lugs 6a1, 6a2 is small, the stopper 10 can apply a strong rotation-blocking force in a direction that is effective for blocking the rotation of the first roller 6.

[0085] In this embodiment, the first roller 6 has a larger diameter than the second roller 7 and reaches closer to the wheel axis Xw than the second roller 7. Therefore, as described above, the outer peripheral edge of the stopper 10 at the stopper action position P2 enters the gap 6s between the lugs 6a1 and 6a2 of the first roller 6 and abuts against the lug 6a1 and / or 6a2, thereby preventing rotation of the first roller 6 in the roller rotation direction (the direction along the roller circumferential line Cr1). In this way, the stopper 10 prevents rotation of the multiple first rollers 6 but does not prevent rotation of the multiple second rollers 7.

[0086] That is, in this embodiment, the stopper 10 does not prevent the rotation of the second roller 7 by applying a frictional force, but rather allows only the outer peripheral edge portion thereof to enter the gap 6s between the lugs 6a1, 6a2 of the first roller 6, thereby making the lugs 6a1, 6a2 of the first roller 6 the engaging portions on one and the other sides in the direction of rotation. Therefore, the omnidirectional wheel 1 equipped with such stopper 10 is effective in terms of the aforementioned miniaturization of components, simplification of structure, reduction in cost, and improvement of durability.

[0087] The specific structure of the stopper 10 according to this embodiment, particularly with regard to switching between the stopper release position P1 and the stopper operating position P2, will now be described in detail. As described above, the wheel cover plate 9 is attached to the wheel outer end surface 4c of the wheel member 4 and the outer end surface (the end surface on the wheel outer side K3) of the bracket 5. As shown in Figures 6 and 8, the stopper shaft 11 protrudes from the wheel outer end of the hub 2 along the wheel axis Xw so as to pass through the wheel cover plate 9.

[0088] The stopper shaft 11 is inserted into the center hole of the disc-shaped stopper 10. On the stopper shaft 11, the stopper 10 is movable forward and backward (relatively movable) in the axial direction, i.e., in the wheel axial direction K1. By moving along this stopper shaft 11, the stopper 10 can be changed between a stopper release position (roller rotation permitting position) P1 shown in Figures 6 and 7 and a stopper action position (roller rotation preventing position) P2 shown in Figures 8 and 9.

[0089] In this embodiment, as described above, the stopper shaft 11 extending from the hub 2 is inserted into the center hole of the disc-shaped stopper 10, but this is not limiting. In order to allow the stopper 10 to move back and forth in the wheel axial direction K1 between the stopper release position P1 and the stopper action position P2, for example, a plurality of rod members may be provided to protrude from the wheel outer end face 4c of the wheel member 4 provided around the hub 2 to the wheel outer side K3, and these rod members may be inserted into the stopper 10 so as to be relatively movable.

[0090] In this embodiment, the stopper shaft 11 is a threaded shaft. For example, when positioning the stopper 10 at the stopper release position P1 shown in Fig. 6, a spacer nut 13 is screwed onto the stopper shaft 11. First, the stopper 10 is attached to the stopper shaft 11 at a position K3 on the wheel outer side than the spacer nut 13. Next, a fixing nut 12 is screwed onto the stopper shaft 11 at a position K3 on the wheel outer side than the stopper 10, and the stopper 10 is sandwiched and tightened between the fixing nut 12 and the spacer nut 13. As a result, the stopper 10 is fixed at the stopper release position P1, which is a certain distance away from the wheel cover plate 9 on the wheel outer side K3 in the wheel axis direction K1.

[0091] 6, two spacer nuts 13 are used to position the stopper 10 at the stopper release position P1, but the present invention is not limited to this. The number and size of the spacer nuts 13 may be determined according to the distance between the wheel cover plate 9 and the spacer nuts 13, which is set according to the diameter of the rollers 6 and 7 and the shapes of the lugs 6a and 7a.

[0092] In the above example, the spacer that is interposed between the wheel cover plate 9 and the stopper 10 and positions the stopper 10 at the stopper release position P1 is described as a nut as shown in the drawings, but is not limited to this. For example, the spacer may be a cylindrical member or the like having an axial length equal to the desired distance between the wheel cover plate 9 and the stopper 10.

[0093] In this way, the stopper 10 at the stopper release position P1 has no portions that come into contact with any of the rollers 6 and 7. Therefore, with respect to the stopper 10 at the stopper release position P1, all of the rollers 6 and 7 are free to rotate in the roller rotation direction Cr.

[0094] 8 and 9, the stopper 10 is attached to the stopper shaft 11 with the spacer nut 13 removed from the stopper shaft 11 (not provided on the stopper shaft 11). Furthermore, the fixing nut 12 is threaded onto the stopper shaft 11 at the wheel outer side K3 from the stopper 10 and then tightened toward the wheel inner side K2. As a result, the stopper 10 is fixed in position at the stopper action position P2 near the wheel cover plate 9 in the wheel axis direction K1.

[0095] As described above, the stopper 10 can be switched between a stopper release position P1 where it is disengaged from the rollers 6, 7 and a stopper engagement position P2 where it engages the rollers 6 by moving back and forth in the direction along the hub 2 (wheel axis Xw).

[0096] With the above configuration, the stopper 10 at the stopper action position P2 prevents rotation of at least the first roller 6, which has a larger diameter, of the rollers 6, 7, in the roller rotation direction Cr (direction along the first roller circumferential line Cr1). Having the stopper 10 at the stopper action position P2 in this way allows the omnidirectional wheel 1 to function as a wheel that rotates only in the wheel rotation direction (direction along the wheel circumferential line Cw; hereinafter referred to as the "wheel rotation direction Cw") about the wheel axis Xw, just like a normal wheel.

[0097] For example, when an agricultural vehicle equipped with omnidirectional wheels 1 is moved on a paved road to a field, it may be necessary to rotate the wheels only in the wheel rotation direction Cw to reliably transmit the driving force of the wheels to the road in the forward direction. In such a case, it is conceivable to set the stopper 10 to the stopper operating position P2 to reliably rotate the omnidirectional wheels 1 in the wheel rotation direction Cw.

[0098] On the other hand, an agricultural vehicle equipped with omnidirectional wheels 1 may repeatedly perform pivot turns and spin turns while traveling in a field with soft soil. In such cases, it is desirable for the rollers 6 and 7 to rotate not only in the wheel rotation direction Cw of the omnidirectional wheels 1 but also in the roller rotation direction Cr, which is perpendicular to the wheel rotation direction Cw, to exert traction force on the soft soil. In such cases, it is possible to set the stopper 10 to the stopper release position P1, allowing the omnidirectional wheels 1 to rotate freely in both the wheel rotation direction Cw and the roller rotation direction Cr.

[0099] In addition, in this embodiment, as shown in Figure 9, the stopper 10 moves along the wheel axis Xw to the inner side K2 of the wheel, and abuts against the lug 6a (6a1, 6a2), thereby preventing the rotation of the first roller 6 in the roller rotation direction Cr, so the stopper 10 has a simple disk shape.

[0100] However, there are various methods for preventing the rotation of the rollers 6 (and / or rollers 7) other than the above-described method of abutting (making it possible for the abutment) the plate-shaped stopper 10 against the lug 6a, which is the protruding portion of the first roller 6. The shape, structure, etc. of the stopper 10 may be changed depending on the method selected from the various methods.

[0101] 10, a recess 10a, which is an annular groove centered on the wheel axis Xw, is formed on the wheel inner side K2 of the stopper 10. When the stopper 10 is placed in the stopper action position P2, the lug 6a of the first roller 6 fits into the recess 10a, thereby preventing the first roller 6 from rotating in the roller rotation direction.

[0102] Alternatively, the stopper 10 may be provided with teeth or claws, and the rotation of the first roller 6 may be locked by inserting the teeth or claws between the lugs 6a.

[0103] In the above example, the stopper 10 disposed at the stopper action position P2 restricts the rotation of the first roller 6. However, the stopper 10 at the stopper action position P2 only needs to restrict the rotation of at least the first roller 6, and may also restrict the rotation of the second roller 7 in addition to the first roller 6.

[0104] In this embodiment, the position can be changed between the stopper release position P1 and the stopper application position P2 depending on whether or not a spacer such as the illustrated spacer nut 13 is interposed between the stopper 10 and the wheel cover plate 9. Therefore, when changing the position to attach or detach the spacer, the stopper 10 and the fixing nut 12 must also be temporarily removed from the stopper shaft 11, as shown in FIG.

[0105] Therefore, it is conceivable to provide an actuator on the omni-directional wheel 1 for moving the stopper 10 in the wheel axis direction K1. This actuator may be, for example, a telescopic actuator such as a hydraulic cylinder, or a rotary actuator such as a hydraulic motor. In addition to hydraulic actuators, various actuators such as pneumatic actuators and electric actuators (e.g., electric motors) can serve as the actuator.

[0106] 18 to 20, the stopper control actuator is controlled by a control device 110 (described later) that is included in the work vehicle 100. The stopper control actuator can be operated by a worker sitting in the driver's seat of the work vehicle 100 and operating an operating tool to activate the actuator.

[0107] Furthermore, when an operator remotely controls work vehicle 100 using terminal device 135, the operator may operate terminal device 135 while taking into consideration the soil conditions displayed on a monitor, and control device 110 may control the stopper control actuator. Furthermore, if the vehicle is an autonomous vehicle, control device 110 may make a judgment based on detected soil conditions, etc., and control the stopper control actuator.

[0108] Next, a work vehicle 100 shown in Figures 18 to 20 will be described as an example of a work vehicle equipped with omnidirectional wheels 1. The work vehicle 100 shown in Figures 18 to 20 is a tractor to which a work implement can be attached.

[0109] The work vehicle 100 shown in Figures 18 to 20 comprises a body 101, first wheels 102 which are left and right omnidirectional wheels 1 supported on both the left and right sides of the body 101, a drive unit 105, and left and right second wheels 103 which are drive wheels supported on both the left and right sides of the body 101 in front of or behind the first wheels 102 and driven by the drive unit 105.

[0110] In the embodiment shown in FIGS. 18 to 20, the second wheel 103 is a tire-type wheel that, unlike the omnidirectional wheel 1, is a unidirectional wheel that can rotate in one direction (see the wheel rotation direction Cw of the omnidirectional wheel 1). Specifically, the second wheel 103 is a unidirectional wheel that rotates only in the rotation direction of the rotation shaft that supports the second wheel 103, i.e., only in the forward and backward directions. The second wheel 103 may also be a drive wheel (or drive sprocket) of a crawler-type traveling device. Alternatively, the second wheel 103, which is a drive wheel, may also be an omnidirectional wheel 1, and both the front and rear wheels of the work vehicle 100 may be omnidirectional wheels 1. Alternatively, the first wheel 102, which is an omnidirectional wheel 1, may be a rear wheel of the work vehicle 100, and the second wheel 103, which is a drive wheel, may be a front wheel of the work vehicle 100.

[0111] On the other hand, the first wheel 102 is an omnidirectional wheel 1. A rotation axis 2 (hub) of the first wheel 102 (omnidirectional wheel 1) is attached to a frame (in this embodiment, a knuckle arm 102a, described later) provided on the vehicle body 101. Note that the omnidirectional wheel 1 is not a tire-type wheel because the rollers 6, 7 do not constitute a tire. However, all of the rollers 6, 7 arranged along the outer periphery of the wheel member 4 rotate in the wheel rotation direction Cw, like a single tire.

[0112] The work vehicle 100 is also equipped with a first body turning device S1. The first body turning device S1 turns the body 101 by varying the rotation speed and / or rotation direction of the left and right second wheels 103. In the work vehicle 100, while the body 101 is turning by this first body turning device S1, the rollers (first roller 6 and / or second roller 7) that are in contact with the ground among the multiple rollers 6, 7 of the first wheel 102 can rotate in a second direction (roller rotation direction Cr). This rotation of the rollers allows the first body turning device S1 to smoothly turn the body 101 (i.e., change the traveling direction of the work vehicle 100).

[0113] The work vehicle 100 changes its traveling direction, i.e., turns the body 101, by using the first body turning device S1 to vary the rotational speeds of the left and right second wheels 103, which are drive wheels, and / or to vary the rotational directions of the left and right second wheels 103 (i.e., differentially rotate the left and right second wheels 103). The first body turning device S1 of the work vehicle 100 can also perform a pivot turn (spin turn) by reversing the rotation directions of the left and right second wheels 103. The first body turning device S1 of the work vehicle 100 can also perform a pivot turn (pivot turn) of the body 101 by stopping the rotation of one of the left and right second wheels 103 and rotating only the other second wheel 103.

[0114] Here, the state of the omnidirectional wheel 1 when the work vehicle 100 (body 101) makes a pivot turn will be described with reference to Figure 18. Figure 18 illustrates the state of the work vehicle 100 making a pivot turn counterclockwise. That is, the left second wheel 103 (left rear wheel 103L in this embodiment) on the inside of the turn rotates in the reverse (reverse rotation) direction Ci and moves in the reverse direction Mr. On the other hand, the right second wheel 103 (right rear wheel 103R in this embodiment) on the outside of the turn rotates in the forward (forward rotation) direction Co and moves in the forward direction Mf.

[0115] Due to such rotation of the left and right second wheels 103, the body 101 makes a pivot turn along a turning direction T, which is a horizontal rotation direction with the midpoint between the left and right second wheels 103 as the turning center. The first wheel 102 moves in the turning direction T together with the body 101 making the pivot turn. This movement in the turning direction T is not a rotational movement along the original rotation direction of the first wheel 102 as a wheel (the wheel rotation direction Cw described above), but a movement along the wheel axis Xw that is perpendicular to the wheel rotation direction Cw.

[0116] Here, in the work vehicle 100 according to this embodiment, an omnidirectional wheel 1 that can rotate in a wheel rotation direction Cw (first direction) and a roller rotation direction Cr (second direction) that is perpendicular to the wheel rotation direction Cw is used as the first wheel 102. The turning direction T is a direction that matches the roller rotation direction Cr of the first roller 6 or second roller 7 that comes into contact with the ground on the omnidirectional wheel 1. As a result, the first roller 6 or second roller 7 of the first wheel 102 that is in contact with the ground rotates along the roller rotation direction Cr, smoothing the movement of the first wheel 102 along the turning direction T. In addition, the load due to friction on the first roller 6 or second roller 7 that is in contact with the ground is reduced.

[0117] In the work vehicle 100, the driving device 105 of the traveling system, as will be described in detail later, can drive the left and right second wheels 103 independently of each other and at different rotational speeds and / or rotational directions. This driving device 105 functions as the first vehicle body turning device S1.

[0118] The work vehicle 100 may be provided with individual brakes or clutches (side clutches) on the left and right second wheels 103. In such a case, the work vehicle 100 can perform a pivot turn of the vehicle body 101 by applying the brake or disengaging the clutch of only one of the second wheels 103 to stop (or slow down) its rotation and rotating only the other second wheel 103. In such a case, the mechanism for operating the brakes of the left and right second wheels 103 or the mechanism for operating the clutches of the left and right second wheels 103 functions as a first vehicle body turning device S1 that turns the vehicle body 101 by varying the rotational speed and / or rotational direction of the left and right second wheels 103.

[0119] Furthermore, in the work vehicle 100, the left and right first wheels 102 and / or the left and right second wheels 103 may be steered wheels. A steered wheel is a wheel whose angle in the left and right direction relative to the vehicle body 101 can be changed, that is, whose turning angle (steering angle) in the left and right directions can be changed. When the work vehicle 100 is equipped with such steered wheels, it is equipped with a steering device 120 that changes the angle (steering angle) of the steered wheels in the left and right direction relative to the vehicle body 101.

[0120] When the work vehicle 100 is equipped with a first body turning device S1 that drives the left and right second wheels 103, which are drive wheels, at different rotational speeds and / or directions to turn the body 101 as described above, the work vehicle 100 may be equipped with such a steering device 120 as a second body turning device S2.

[0121] As will be described in detail later, the work vehicle 100 shown in Figures 19 and 20 is equipped with a drive unit 105 for driving the second wheel 103, which is a drive wheel, and a steering unit 120 for steering the first wheel 102, which is a steered wheel, with the drive unit 105 functioning as the first body turning device S1 and the steering unit 120 functioning as the second body turning device S2.

[0122] As shown in Figures 18 to 20, the first embodiment employs a tractor as an agricultural machine that can be fitted with a work device (implement) as the work vehicle 100 configured as described above (i.e., wheeled type). However, the work vehicle 100 equipped with omni-directional wheels 1 is not limited to tractors, and can be used as a work vehicle for a variety of uses and fields, such as agriculture and construction work. For example, combine harvesters and rice transplanters are possible examples of agricultural work vehicles. Furthermore, skid steer loaders, which are a type of wheel loader, are possible examples of construction work vehicles. For convenience of explanation, the structure of the work vehicle 100 will be described in detail below using a tractor as an example.

[0123] The work vehicle 100 shown in Figures 18 to 20 has a vehicle body 101 (machine body) supporting left and right first wheels 102, i.e., a left front wheel 102L and a right front wheel 102R, and left and right second wheels 103, i.e., a left rear wheel 103L and a right rear wheel 103R.

[0124] The vehicle body 101 supports various devices (on-board devices) provided on the work vehicle 100, such as the prime mover 104 and drive unit 105. An internal combustion engine, an electric motor, or the like may be used as the prime mover 104. If the prime mover 104 is an internal combustion engine, the work vehicle 100 is provided with a fuel tank provided on the vehicle body 101 for storing fuel to be supplied to the internal combustion engine serving as the prime mover 104. If the prime mover 104 is an electric motor, the work vehicle 100 is provided with a battery provided on the vehicle body 101 for storing power to be supplied to the electric motor serving as the prime mover 104.

[0125] Next, the working system structure of the work vehicle 100 as a tractor will be described. A working implement, such as an agricultural work implement for working in a field, is coupled to the vehicle body 101. Specifically, the working implement is coupled to the vehicle body 101 via a coupling device 115 provided at the front and / or rear of the vehicle body 101. The working implements as agricultural work implements include a tilling implement for tilling a field, a tilling implement for plowing, a ridge forming implement for forming ridges, a fertilizer spreading implement for spreading fertilizer, a pesticide spreading implement for spraying pesticides for pest control, a seed spreading implement for sowing seeds, a transplanter for planting crops (seedlings), a harvesting implement for harvesting crops, a reaping implement for reaping grass and the like, a spreading implement for spreading grass and the like, a grass collecting implement for collecting grass and the like, and a shaping implement for shaping grass and the like. The operator can select a working implement from the various types of working implements described above and couple it to the coupling device 115.

[0126] 18 to 20, the coupling device 115 is provided at the rear of the vehicle body 101, and couples a working device to the rear of the vehicle body 101. The coupling device 115 is configured, for example, with a three-point link mechanism. Also, as shown in FIG. 20, the coupling device 115 is equipped with one or more working hydraulic actuators 116 (hydraulic cylinders, etc.) for raising and lowering the working device attached to the coupling device 115 and adjusting the attitude of the working device.

[0127] In relation to the operation of the work hydraulic actuator 116, a control valve unit 112 is provided on the vehicle body 101, as shown in Figure 20. The work hydraulic actuator 116 is operated by receiving a supply of hydraulic oil via a control valve for controlling the work hydraulic actuator 116, which is included in the control valve unit 112. The control valve is a solenoid valve, and the amount of operation, direction of operation, etc. of the work hydraulic actuator 116 are controlled by a control device 110, which will be described later.

[0128] 20, a PTO shaft 113, which is a power take-off shaft, is provided at the front and / or rear of the vehicle body 101. If the work implement connected to the vehicle body 101 via the coupling device 115 is equipped with a work drive device (for example, if the work implement is a rotary tillage implement, a transmission mechanism that rotates and drives the tillage tine shaft), power from a prime mover 104 mounted on the vehicle body 101 of the work vehicle 100 is input to the drive device of the work implement via the PTO shaft 113.

[0129] In the vehicle body 101, a PTO transmission mechanism 114 is interposed midway along the power transmission system from the prime mover 104 to the PTO shaft 113. The PTO transmission mechanism 114 includes a PTO clutch that switches on and off the transmission of power from the prime mover 104 to the PTO shaft 113, a PTO transmission device that changes the rotational speed ratio of the PTO shaft 113 to the output rotation of the prime mover 104, and / or a PTO brake that stops the inertial rotation of the PTO shaft 113 when the PTO clutch is disengaged.

[0130] The PTO transmission mechanism 114 includes hydraulic actuators such as a piston for switching on and off the PTO clutch, which is a hydraulic clutch, and a shifter for selecting gears in the PTO transmission, which is a gear-type transmission. The control device 110 controls the corresponding control valves included in the control valve unit 112, thereby controlling the amount and / or direction of operation of the hydraulic actuators of the PTO transmission mechanism 114.

[0131] Note that, in order to apply driving force from the work vehicle 100 to the working implement attached to the coupling device 115, in addition to the PTO shaft 113 as shown in Fig. 20, for example, a port (AUX port) for taking out hydraulic pressure from the work vehicle 100 may be provided, and hydraulic oil may be supplied from the work vehicle 100 to the hydraulic drive device provided on the working implement via the relevant control valve and AUX port in the control valve unit 112. Alternatively, if the working implement is equipped with an electric drive device, a control signal may be sent from the control device 110 of the work vehicle 100 to the drive device of the working implement via wired or wireless communication means.

[0132] Next, we will explain the traveling system structure of the work vehicle 100. The drive unit 105 of the traveling system of the work vehicle 100 drives the left rear wheel 103L and right rear wheel 103R (left and right second wheels 103), which are drive wheels, independently of each other. As the drive unit 105 having this structure, the work vehicle 100 is equipped with a pair of hydrostatic stepless transmissions (hereinafter referred to as "HST") 107, that is, a left HST 107L and a right HST 107R, as shown in FIG.

[0133] In the left HST 107L, a travel motor (hydraulic motor) 109L for driving the left rear wheel 103L and a hydraulic pump 108L that discharges hydraulic oil to the left travel motor 109L are fluidly connected via a pair of oil passages. In the right HST 107R, a travel motor (hydraulic motor) 109R for driving the right rear wheel 103R and a hydraulic pump 108R that discharges hydraulic oil to the right travel motor 109R are fluidly connected via a pair of oil passages.

[0134] The output shaft (motor shaft) of the left traveling motor 109L is operatively connected to the axle 103a of the left rear wheel 103L, which is the second left wheel 103. The output shaft (motor shaft) of the right traveling motor 109R is operatively connected to the axle 103a of the right rear wheel 103R, which is the second right wheel 103 (hereinafter, the traveling motors 109L and 109R will be collectively referred to as "traveling motor 109").

[0135] 20, the motor shaft of the traveling motor 109 and the axle 103a of the second wheel 103 are directly connected on the same axis. However, a transmission mechanism (such as a reduction mechanism) of a gear type or an endless belt type may be interposed between the motor shaft of the traveling motor 109 and the axle 103a of the second wheel 103.

[0136] The input shafts 108b of the hydraulic pumps 108L, 108R (collectively referred to as hydraulic pumps 108) are driven by the prime mover 104. Note that FIG. 20 does not illustrate a state in which the input shafts (pump shafts) 108b of the hydraulic pumps 108L, 108R are interlocked with the output shafts of the prime mover 104. Specific examples of a structure interlocking the prime mover 104 with the hydraulic pumps 108L, 108R include a gear-type transmission mechanism and a transmission mechanism using an endless belt such as a belt or chain. Furthermore, such a transmission mechanism may be a transmission mechanism with a speed change function that can change the speed ratio between the input side (prime mover 104 side) and the output side (hydraulic pump 108 side). Alternatively, such a transmission mechanism may not be provided, and the output shafts of the prime mover 104 may be directly connected to the input shafts (pump shafts) 108b of the hydraulic pumps 108L, 108R.

[0137] The hydraulic pumps 108 (108L, 108R) are variable displacement hydraulic pumps that are configured to be able to switch the flow direction of the hydraulic oil they discharge, and each includes a movable swash plate 108a. When the movable swash plate 108a is in the neutral position, the hydraulic pump 108 does not discharge hydraulic oil, and the rotation of the travel motor 109 and the second wheel 103 is stopped.

[0138] By tilting the movable swash plate 108a from the neutral position to the forward tilting direction, the travel motor 109 is rotated in the forward direction at a speed according to the tilt angle of the movable swash plate 108a by the unidirectional oil flow of the discharged oil from the hydraulic pump 108. As a result, the travel motor 109 rotates the second wheel 103 forward at that speed.

[0139] Furthermore, by tilting the movable swash plate 108a from the neutral position in the tilting direction for reverse travel, the oil flow in the other direction of the discharged oil from the hydraulic pump 108 rotates the traveling motor 109 in the reverse direction at a speed according to the tilt angle of the movable swash plate 108a. As a result, the traveling motor 109 rotates the second wheel 103 in reverse at that speed.

[0140] Therefore, by providing a difference in tilt angle or tilt direction between the movable swash plate 108a of the hydraulic pump 108L of the left HST 107L and the movable swash plate 108a of the hydraulic pump 108R of the right HST 107R, it is possible to make the flow rate and / or flow direction of the hydraulic oil discharged by the hydraulic pump 108L of the left HST 107L and the hydraulic pump 108R of the right HST 107R different. This makes it possible to make the rotational speed and / or rotational direction of the left traveling motor 109L and the right traveling motor 109R different, and to make the rotational speed and / or rotational direction of the left rear wheel 103L and the right rear wheel 103R different, thereby turning the body 101 (making the work vehicle 100 turn left or right).

[0141] In other words, in the work vehicle 100, the traveling system drive device 105 includes a pair of HSTs 107L and 107R, and functions as a first body turning device S1 that turns the body 101 by varying the rotation speed and / or rotation direction of the second wheels 103, which are the left and right drive wheels.

[0142] In the work vehicle 100 shown in FIG. 20, pilot pressure oil is applied to the pilot pressure receiving portions of the movable swash plates 108a of the hydraulic pumps 108L and 108R via the corresponding control valves (regulators) included in the control valve unit 112.

[0143] The control valves included in the control valve unit 112 are solenoid valves, and the excitation and de-energization of the solenoids are controlled in response to control signals output from the control device 110. Therefore, the control valves serving as regulators for controlling the movable swash plate 108a are also position (spool) controlled by the control device 110. In other words, the control device 110 controls the movable swash plates 108a of the hydraulic pumps 108L and 108R so that the driving device 105 of the traveling system functions as the first vehicle-body swing device S1.

[0144] The control of the movable swash plate 108a of the hydraulic pumps 108L, 108R by the control device 110 can be switched among a first mode (normal mode) in which the rotational speeds and rotational directions of the pair of second wheels 103 are made to match, a second mode (turning mode) in which the rotational directions of the pair of second wheels 103 are made to match but the rotational speeds are made different, and a third mode (spin turn mode) in which the rotational speeds of the pair of second wheels 103 are made to match but the rotational directions are made different. Therefore, when the control device 110 controls the movable swash plate 108a in the second mode or the third mode, the drive device 105 functions as the first vehicle-body turning device S1.

[0145] The control device 110 is a processing circuit including one or more processors. The control device 110 performs various controls related to the work vehicle 100, including controlling the movable swash plates 108a of the hydraulic pumps 108L, 108R so that the drive device 105 functions as the first vehicle-body swing device S1, as described above. The control device 110 is communicably connected to various devices mounted on the work vehicle 100 via an on-board network such as CAN, ISOBUS, LIN, or FlexRay.

[0146] The control device 110 includes one or more memories, various analog circuits, various digital circuits, etc. The one or more memories store (memorize) software programs and various data to be executed by one or more processors. The control device 110 can read software programs from one or more memories using one or more processors and execute various processes based on the software programs. Note that the control device 110 may also be able to execute various processes based on predetermined logic circuits using one or more processors.

[0147] The processor may be, for example, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC).

[0148] The control device 110 may execute various processes by having multiple physically separated processors cooperate with each other, and the configuration is not limited to the configuration described above. In such a case, the multiple processors are mounted on one or more computers that are physically separated from the work vehicle 100, and these processors are connected to each other so as to be able to communicate with each other via a network such as an in-vehicle network, a LAN, a WAN, or the Internet.

[0149] In addition, the software program may be stored in a recording medium (non-volatile memory such as HDD, SSD, CD-ROM, DVD-ROM, etc.) communicatively connected to the control device 110, or in an external server device connected via the network, and installed from there into the memory.

[0150] The work vehicle 100 may be a vehicle that can be driven manned or unmanned. Furthermore, the work vehicle 100 may be a vehicle that can be driven either manned or unmanned. The work vehicle 100 shown in Fig. 20 is equipped with an input device 131 and a detection device 132, which will be described later, so that it can be driven either manned or unmanned.

[0151] When the work vehicle 100 is capable of being operated by a person, a driver's seat is mounted on the vehicle body 101, and an input device 131 such as an input interface and operating tools such as a joystick and switches that are operated by the worker sitting in the driver's seat is also provided. The input device 131 is electrically connected to the control device 110 as shown in FIG. 20.

[0152] The control device 110 controls the corresponding control valve in the control valve unit 112 based on an input signal obtained by an operator operating the input device 131. By controlling the control valve by the control device 110 based on the signal obtained from the input device 131 in this way, for example, the tilt angle and tilt direction of the movable swash plates 108a of the hydraulic pumps 108L and 108R are changed, and the drive device 105 functions as the first vehicle body turning device S1, and the vehicle body 101 turns by varying the rotation speed and / or rotation direction of the left and right second wheels 103 (left rear wheel 103L and right rear wheel 103R).

[0153] In addition, the control valve is controlled by the control device 110 based on a signal received from the input device 131, and thereby, for example, a working hydraulic actuator 116 and a PTO transmission mechanism 114 are operated, and the height, posture, driving state, etc. of the working equipment connected to the vehicle body 101 via the connecting device 115 are controlled.

[0154] When the work vehicle 100 is capable of unmanned operation, the work vehicle 100 is provided with a detection device 132 such as a GPS positioning device and an imaging device that captures images of the surrounding environment. The detection device 132 is electrically connected to the control device 110 as shown in Fig. 20. Possible vehicle driving patterns for unmanned operation include automatic driving and remotely controlled driving.

[0155] In the case of autonomous driving, the control device 110 determines a command to one of the control valves included in the control valve unit 112 by, for example, comparing a target position on a preset driving route with the actual vehicle position obtained by detection by the detection device 132. Then, the control device 110 issues the determined command to the corresponding control valve of the control valve unit 112, causing the drive device 105 of the traveling system to function as the first vehicle body turning device S1 to turn the vehicle body 101, or controlling the working hydraulic actuator 116, etc. to raise and lower the working device.

[0156] On the other hand, in the case of traveling by remote control, the worker operates a portable or desktop terminal device 135 or the like to input a signal while checking the monitor display of the detection results of the detection device 132, and transmits the input signal to the control device 110 via an unmanned communication network or the like. The control device 110 determines a command to one of the control valves included in the control valve unit 112 based on the input signal received from the terminal device 135. The control device 110 then issues the determined command to the corresponding control valve in the control valve unit 112, thereby causing the drive device 105 of the traveling system to function as the first vehicle body turning device S1 to turn the vehicle body 101, or controlling the work hydraulic actuator 116 or the like to raise and lower the work implement.

[0157] The control device 110 switches modes in response to the operation of an operation switch that is included in the input device 131 and that accepts a mode selection operation. In the above-described example, the control device 110 can switch between the first to third modes, but the number and combination of modes are not limited to the above-described example as long as the drive device 105 functions as the first body turning device S1 so that at least the body 101 turns and / or makes a sharp turn.

[0158] For example, if the work vehicle 100 is provided with a steering device 120 as the second vehicle body turning device S2, the control device 110 only needs to be able to switch to at least one of the second mode and the third mode in addition to the first mode.

[0159] Furthermore, the work vehicle 100 does not necessarily have to be provided with a steering device 120 as the second vehicle body turning device S2, and in such a case, the control device 110 may be capable of switching to a third mode in addition to the second mode. Also, instead of or in addition to the third mode, the control device 110 may be capable of switching to a fourth mode (pivot turning mode) in which the control device 110 controls the drive device 105 to stop the second wheel 103 on the inside of the pair of second wheels 103 and drive the second wheel 103 on the outside of the pair of second wheels 103.

[0160] The control device 110 may also control the stopper control actuator in conjunction with the mode switching. For example, when the control device 110 controls the movable swash plate 108a in the first mode (normal mode), the control device 110 controls the stopper control actuator to position the stopper 10 at the stopper active position P2, and when the control device 110 controls the movable swash plate 108a in the second mode (swing mode) or the third mode (spin turn mode), the control device 110 controls the stopper 10 at the stopper release position P1.

[0161] Regarding the drive structure of the running system of the work vehicle 100, for example, the axles of the second wheels 103, which are the drive wheels, may be connected by a differential gear device, and the drive device 105 may have a structure with a single (common) output shaft (for example, a single HST or a stepped gear transmission, etc.) instead of a pair of HSTs 107L, 107R having a pair of output shafts (motor shafts of running motors 109L, 109R) for driving the left and right second wheels 103 separately, and output may be from the single output shaft to the differential gear device.

[0162] Even in such a configuration using a differential gear device, the left and right second wheels 103 driven by the drive unit 105 can be driven differentially. However, the differential of the left and right second wheels 103 using such a differential gear device is not a differential for turning the vehicle body 101, but a differential for preventing wheel drag or the like from occurring while the vehicle body 101 is turning, that is, a differential in response to the turning of the vehicle body 101.

[0163] Therefore, when the drive unit 105 is configured to output a driving force shared by the left and right second wheels 103 to the differential gear device as described above, it does not function as the first body turning device S1 that turns the body 101 by varying the rotation speed and / or rotation direction of the left and right second wheels 103.

[0164] Therefore, when the driving device 105 of the traveling system has such a configuration, for example, as described above, it is conceivable to provide individual brakes and / or clutches on the left and right second wheels 103, and have an operating device that operates these brakes and / or clutches function as a first body turning device S1 that turns the body 101 by varying the rotation speed and / or rotation direction of the left and right second wheels 103.

[0165] On the other hand, if the drive device 105 is configured to be able to drive the left and right second wheels 103 at different rotational speeds and / or directions, it can function as a first body turning device S1 that turns the body 101 using the differential between the left and right second wheels 103, and such a configuration is not limited to being realized in cases where it includes a pair of HSTs 107L, 107R as described above.

[0166] For example, instead of the pair of HSTs 107L, 107R, the drive device 105 may include a pair of electric motors, one for driving the left second wheel 103 (left rear wheel 103L) and the other for driving the right second wheel 103 (right rear wheel 103R). In this case, the control device 110 independently controls the outputs of the pair of electric motors so that the pair of electric motors have different rotation speeds and / or rotation directions (for example, independently controls the inverters provided in the pair of electric motors), and the drive device 105 functions as the first vehicle-body turning device S1.

[0167] Furthermore, even if the drive device 105 does not include a pair of hydraulic pumps 108L, 108R (i.e., does not constitute a pair of HSTs 107L, 107R), as long as it includes a pair of hydraulic motors 109, that is, a left travel motor 109L for driving the left second wheel 103 (left rear wheel 103L) and a travel motor 109R for driving the right second wheel 103 (right rear wheel 103R), it can become a first vehicle body turning device S1 that turns the vehicle body 101 by varying the rotation speed and / or rotation direction of the left and right second wheels 103. In this case, for example, it is conceivable that the control valve unit 112 includes a control valve that can change the flow rate and flow direction of hydraulic oil to the left travel motor 109L and a control valve that can change the flow rate and flow direction of hydraulic oil to the travel motor 109R, and the control device 110 independently controls each control valve. In other words, rather than controlling the tilting angle and / or tilting direction of the movable swash plate 108a of the hydraulic pump 108, the traveling motors 109L and 109R can be driven at different rotational speeds and / or rotational directions to turn the vehicle body 101 by controlling the position (spool) of the control valve included in the control valve unit 112.

[0168] Note that the pair of travel (hydraulic) motors 109 (including those included in HSTs 107L, 107R as shown in FIG. 20 and those not constituting an HST as described above) included in drive device 105 as first vehicle body turning device S1, the pair of electric motors described above, etc. may serve as wheel motors and be mounted inside or outside the wheel members that constitute each second wheel 103. In this way, by using wheel motors as the pair of motors (electric motors, hydraulic motors, etc.) for driving the left and right second wheels 103, it is possible to make the work vehicle 100 more compact.

[0169] The work vehicle 100 shown in Figures 19 and 20 further configures the left and right first wheels 102 (left front wheel 102L, right front wheel 102R) which are omnidirectional wheels 1 as steerable wheels with a changeable steering angle. Note that the steering angle is the angle at which the wheels turn, i.e., the left and right rotation angle from the direction of straight forward and backward travel, and as described above, it is also the left and right rotation angle of the steered wheels relative to the vehicle body 101. Each of the first wheels 102 (left front wheel 102L, right front wheel 102R) which are steerable wheels is supported via a knuckle arm 102a so as to be rotatable in the left and right directions relative to the vehicle body 101. Specifically, the rotation shaft 2 (hub) of each first wheel 102 is connected to the knuckle arm 102a.

[0170] The knuckle arms 102a of the left and right first wheels 102 (left front wheel 102L, right front wheel 102R) are connected to each other via a tie rod 126 and a power steering cylinder 125. When the power steering cylinder 125 is actuated, the left and right first wheels 102 rotate left and right around the pivot shafts of the knuckle arms 102a, and the steering angles of the left and right first wheels 102 are changed.

[0171] The work vehicle 100 is equipped with a steering device 120 for changing the steering angle of the first left and right wheels 102, which are steered wheels. The steering device 120 is made up of a steering handle (steering wheel) 121 that can be operated by the worker, a steering shaft (stem) 122 that is the rotation shaft of the steering handle 121, an electric steering motor 124 that rotates the steering shaft 122 via a gear mechanism, a steering valve 123 that is switched by the rotation of the steering shaft 122, and a power steering cylinder 125 that has a piston 125a that operates by switching the steering valve 123.

[0172] The power steering cylinder 125 has a piston 125a and a piston rod 125b extending outward to the left and right from both sides of the piston 125a, and the left and right outer ends of the piston rod 125b are connected to the knuckle arms 102a of the left and right first wheels 102 (left front wheel 102L, right front wheel 102R), respectively. The steering valve 123 changes the amount of oil supplied to oil chambers on both sides of the piston 125a in the steering cylinder 125, thereby sliding the piston rod 125b in the left and right axial directions, and thereby turns the left and right first wheels 102 (left front wheel 102L, right front wheel 102R) left and right relative to the vehicle body 101 via the respective knuckle arms 102a.

[0173] When the work vehicle 100 is being driven by a person, the worker operates the steering handle 121 to rotate the steering shaft (stem) 122. This switches the steering valve 123, activates the power steering cylinder 125, steers the left and right first wheels 102 (left front wheel 102L and right front wheel 102R), and turns the vehicle body 101.

[0174] The steering shaft (stem) 122 is connected to the output shaft of the electric steering motor 124 via a gear mechanism. The rotational drive of the electric steering motor 124 is controlled by the control device 110. When the work vehicle 100 is traveling in an unmanned operation, the control device 110 controls the amount of rotation and / or direction of rotation of the electric steering motor 124 based on signals obtained from the detection device 132, the terminal device 135, etc., and the steering shaft 122 rotates accordingly. This rotation of the steering shaft switches the steering valve 123, operates the power steering cylinder 125, steers the left and right first wheels 102 (left front wheel 102L and right front wheel 102R), and turns the vehicle body 101.

[0175] As described above, in the work vehicle 100 shown in Figure 20, the drive device 105 for driving the second wheel 103, which is the drive wheel, functions as the first body turning device S1, and the steering device 120 for steering the first wheel 102, which is the steered wheel, functions as the second body turning device S2.

[0176] Here, the first wheel 102, which is the steering wheel, is an omnidirectional wheel 1. Therefore, the roller 6 and / or roller 7 of the first wheel 102 that is in contact with the ground rotates in a roller rotation direction Cr that is different from the wheel rotation direction Cw, thereby smoothing the left and right rotation of the first wheel 102 by the steering device 120. In other words, because the first wheel 102, which is the steering wheel, is an omnidirectional wheel 1, the turning of the vehicle body 101 by the steering device 120 can be smoothed.

[0177] It is also conceivable that, while the first body-turning device S1 is turning the body 101 by differentially rotating the left and right second wheels 103, the second body-turning device S2 may steer the first wheel 102 to assist in the turning. In this case, the rotation of the first wheel 102, whose steering angle has been changed, in the wheel rotation direction Cw and the rotation of the rollers 6, 7 of the first wheel 102, which is the omnidirectional wheel 1, in the roller rotation direction Cr, assist the first body-turning device S1 in turning the body 101 by differentially rotating the left and right second wheels 103.

[0178] The second wheels 103, which are drive wheels, may also be steered wheels. In particular, even though the left and right second wheels 103 are drive wheels, they are driven independently by the respective travel motors 109L, 109R, and therefore are easier to support individually on the vehicle body 101 by knuckle arms so as to be rotatable left and right, compared to left and right drive wheels that are connected to each other via a differential gear device. In other words, the work vehicle 100 can easily be modified to have a structure in which the second wheels 103, which are drive wheels, are steered wheels.

[0179] In this way, when the second wheel 103, which is a drive wheel, is also a steering wheel, the turning of the body 101 of the work vehicle 100 can be achieved by the drive device 105 or the like acting as the first body turning device S1 by varying the rotational speed and / or rotation direction of the left and right second wheels 103, or by the steering device 120 acting as the second body turning device S2 by changing the steering angle of the second wheel 103 (the left and right angle relative to the body 101).

[0180] Furthermore, in the work vehicle 100, when the second wheel 103, which is a drive wheel, is a steered wheel, the first wheel 102 may be a non-steered wheel, and only the second wheel 103 may be a steered wheel. Alternatively, in this case, both the first wheel 102 and the second wheel 103 may be steered wheels, that is, all four wheels may be steered wheels. In other words, in the work vehicle 100, the first wheel 102 and / or the second wheel 103 may be steered wheels.

[0181] Furthermore, in the work vehicle 100, the second wheel 103, which is a drive wheel, may be an omnidirectional wheel 1, and further, the second wheel 103, which is both a drive wheel and a steered wheel, may be an omnidirectional wheel 1. In other words, all four wheels of the work vehicle 100 may be drive wheels, steered wheels, and omnidirectional wheels 1. The work vehicle (rover) 200 in FIG. 22, which will be described in detail later, is an example of a work vehicle in which all four wheels supported by the vehicle body are drive wheels, steered wheels, and omnidirectional wheels 1.

[0182] In addition, for a work vehicle 100 equipped with two body turning devices S1 and S2 as shown in Figure 20, it is possible to allow the worker to select which of the body turning devices S1 and S2 (i.e., the drive device 105 and the steering device 120) to use to turn the body 101.

[0183] For example, when the work vehicle 100 is being driven by a person, the worker may operate the steering handle 121 to select turning of the vehicle body 101 by steering the left and right first wheels 102 (left front wheel 102L, right front wheel 102R) with the steering device 120. Alternatively, the worker may operate a joystick or the like included in the input device 131 to select turning of the vehicle body 101 by differentially driving the left and right second wheels 103 (left rear wheel 103L, right rear wheel 103R) with the drive device 105 (HST 107L, 107R).

[0184] In addition, when the work vehicle 100 is being driven by a person, when the worker is using one of the body turning devices S1, S2 selected by the worker to turn the body 101, the control device 110 may control the other device not selected by the worker to assist in the turning.

[0185] For example, while an operator is steering the left and right first wheels 102 (left front wheel 102L, right front wheel 102R) using the steering handle 121, the control device 110 may control the movable swash plates 108a of the hydraulic pumps 108L, 108R to differentially move the second wheels 103 (left rear wheel 103L, right rear wheel 103R) to assist in turning the vehicle body 101 by steering the first wheels 102.

[0186] Alternatively, when the work vehicle 100 is traveling unmanned, the control device 110 may determine, based on the detection results of the detection device 132, etc., whether the body 101 should be rotated using either the body rotation device S1 or S2, or whether the body 101 should be rotated using both the body rotation devices S1 and S2, and based on this determination, etc., the body 101 may be rotated using the first body rotation device S1 and / or the second body rotation device S2. [Second embodiment] In the first embodiment described above, the work vehicle 100 is described as being equipped with both the first body turning device S1 and the second body turning device S2. However, the work vehicle 100 may be equipped with only one of the first body turning device S1 and the second body turning device S2.

[0187] If the work vehicle 100 is equipped only with the second body turning device S2 (steering device 120) that steers the first wheel 102, which is a steering wheel and an omnidirectional wheel 1, the drive device 105 does not need to be able to make the rotational speed and / or rotational direction of the left and right second wheels 103 different to function as the first body turning device S1, and therefore may be configured to output a driving force shared by the left and right second wheels 103 to a differential gear device that connects the axles of the left and right second wheels 103, as described above.

[0188] On the other hand, as mentioned above, if the work vehicle 100 is equipped with a first body turning device S1 that varies the rotational speed and / or rotational direction of the left and right second wheels 103, which are drive wheels (differentially rotating the left and right second wheels 103), it is also possible to make the first wheels 102 non-steerable wheels and omit the steering device 120 serving as the second body turning device S2. Figure 21 is a diagram showing the drive system structure according to a second embodiment of a work vehicle (tractor) 100 equipped with omnidirectional wheels 1. The work vehicle 100 of the second embodiment shown in Figure 21 realizes such a structure.

[0189] The work vehicle 100 in Fig. 21 will be described. Note that components, parts, etc. designated by the same reference numerals as those shown in Fig. 20 are the same as or similar to those designated by the same reference numerals in Fig. 20, and descriptions thereof will be omitted unless otherwise specified.

[0190] In the work vehicle 100 of Figure 21, the drive unit 105, like the drive unit 105 of Figure 20, is equipped with a pair of HSTs 107L, 107R consisting of an HST 107L for driving the left second wheel 103 (left rear wheel 103L) and an HST 107R for driving the right second wheel 103 (right rear wheel 103R), and functions as a first body turning device S1.

[0191] On the other hand, the first wheels 102 (left front wheel 102L, right front wheel 102R) of the omnidirectional wheel 1 are not steered wheels supported on the vehicle body 101 via knuckle arms 102a. In FIG. 21 , the first wheels 102 of the omnidirectional wheel 1 are provided at the outer end of an axle 102b that extends in the left-right direction and is rotatably supported on the vehicle body 101, and cannot rotate left or right relative to the vehicle body 101. That is, in the second embodiment, the first wheels 102 are not provided with a hub 2 or a bearing 3, and the wheel member 4 is attached to the axle 102b that is rotatably supported on the vehicle body 101. That is, the rotation axis of the first wheels 102 in the second embodiment is the axle 102b.

[0192] Therefore, for example, when the drive unit 105 (HST 107L, 107R) functions as the first body turning device S1 and the body 101 makes a pivot turn or a super pivot turn, the left and right first wheels 102 remain in contact with the ground and move as the body 101 turns without rotating left or right relative to the body 101.

[0193] Here, since the first wheel 102 is an omnidirectional wheel 1, the turning direction of the vehicle body 101 (turning direction T shown in Figure 18) coincides with the rotation direction (roller rotation direction Cr) of the first roller 6 or second roller 7 in contact with the ground, so the first roller 6 or second roller 7 in contact with the ground rotates, and the first wheel 102 does not skid (slide with friction) on the ground.

[0194] 21 is a four-wheel drive vehicle in which the first wheels 102, which are omnidirectional wheels 1, are also driven wheels. As a structure for transmitting driving force to the left and right first wheels 102, a transmission mechanism 140 is provided on each of the left and right sides of the vehicle body 101, which interlocks and connects the axle 102b of the first wheel 102 and the axle 103a of the second wheel 103 on the same left or right side of the vehicle body 101.

[0195] The transmission mechanism 140 includes a left transmission mechanism 140L and a right transmission mechanism 140R. The left transmission mechanism 140L transmits the output of the left traveling motor 109L to the axle 102b of the left front wheel 102L, which is the first left wheel 102. Therefore, the left transmission mechanism 140L synchronizes the rotation of the left front wheel 102L with the rotation of the left rear wheel 103L. The right transmission mechanism 140R transmits the output of the right traveling motor 109R to the axle 102b of the right front wheel 102R, which is the first right wheel 102. Therefore, the right transmission mechanism 140R synchronizes the rotation of the right front wheel 102R with the rotation of the right rear wheel 103R.

[0196] 21, each transmission mechanism 140 includes a transmission shaft 141 having universal joints at both ends. One end (rear end) of the transmission shaft 141 is connected via a bevel gear mechanism to the motor shaft of the travel motor 109, which is operatively linked to the axle 103a of the second wheel (rear wheel) 103. The other end (front end) of the transmission shaft 141 is connected via a bevel gear mechanism to the axle 102b of the first wheel (front wheel) 102.

[0197] However, the power transmission mechanism 140 may have any structure as long as it interlocks and connects the axle 102b of the first wheel 102 and the axle 103a of the second wheel 103 on the same left or right side of the vehicle body 101. In other words, the power transmission mechanism 140 is not limited to one using a transmission shaft 141 with a universal joint and a bevel gear mechanism as shown in Fig. 21, but may have a structure that interlocks and connects the motor shaft of the traveling motor 109 and the axle 102b of the first wheel 102 using, for example, a belt-pulley mechanism or a chain-sprocket mechanism.

[0198] Furthermore, if the axles 102b of the left and right first wheels 102 (left front wheel 102L and right front wheel 102R) are connected to each other by a differential gear device and the output of the drive unit 105 is transmitted to this differential gear device, then only one transmission shaft can be used to transmit power to the differential gear device.

[0199] 21, however, in order to turn the vehicle body 101 by causing the drive unit 105 to function as the first vehicle body turning device S1, it is necessary to ensure a difference in rotational speed and / or a difference in rotational direction between the left and right second wheels 103 (the left rear wheel 103L and the right rear wheel 103R) during the turn. To achieve this, it is necessary to separate the axles 102b of the left and right first wheels 102 (the left front wheel 102L and the right front wheel 102R) so that the rotations (changes in rotational speed and rotational direction) of the first wheel 102 and the second wheel 103 on the same left and right side of the vehicle body 101 (the left front wheel 102L and the left rear wheel 103L, and the right front wheel 102R and the right rear wheel 103R) can be synchronized.

[0200] For this reason, in the work vehicle 100 of Figure 21, the axles 102b of the left and right first wheels 102 (left front wheel 102L and right front wheel 102R) are not connected to each other by a differential gear device. Instead, the work vehicle 100 of Figure 21 is provided with two separate transmission shafts 141, and each transmission shaft 141 interconnects the first wheel 102 and second wheel 103 (travel motor 109 interconnected to) on the same left or right side of the vehicle body 101.

[0201] 21 is capable of switching the travel mode between four-wheel drive mode and two-wheel drive mode. For this reason, in each transmission mechanism 140, a clutch 142 is provided between the transmission shaft 141 and the axle 102b of the corresponding first wheel 102. By simultaneously engaging the clutches 142 of the left transmission mechanism 140L and the right transmission mechanism 140R, the travel mode of the work vehicle 100 is set to four-wheel drive mode (a mode in which both the first wheel 102 and the second wheel 103 are driven). By simultaneously disengaging the clutches 142 of the left transmission mechanism 140L and the right transmission mechanism 140R, the travel mode of the work vehicle 100 is set to two-wheel drive mode (a mode in which only the second wheel 103 is driven).

[0202] The clutch 142 is a hydraulic clutch, and is switched on and off by a hydraulic actuator 143 such as a hydraulically operated piston. Hydraulic oil is supplied to the hydraulic actuator 143 via a corresponding control valve. The control valve is controlled by the control device 110, which operates the hydraulic actuator 143 to switch the clutch 142. When the work vehicle 100 is being driven by a person, the worker operates a travel mode selection switch or the like included in the input device 131, and the control device 110 reads a signal from the switch or the like and controls the control valve for controlling the hydraulic actuator 143.

[0203] It should be noted that the clutch 142 is not limited to a hydraulic clutch, and may be an electromagnetic clutch, etc. In this case, a hydraulic actuator for turning the clutch 142 on and off and a corresponding control valve are not provided. [Third embodiment] In the first and second embodiments described above, a tractor has been used as an example of a work vehicle equipped with omnidirectional wheels 1, but work vehicles other than tractors may also be equipped with omnidirectional wheels 1. Figure 22 is a perspective view of a work vehicle (rover) 200 according to a third embodiment equipped with omnidirectional wheels 1. The work vehicle 200 is, for example, an unmanned exploration vehicle (rover).

[0204] The work vehicle 200 has a main body case 201 mounted on a traveling frame (vehicle body) 202. The work vehicle 200 also supports omnidirectional wheels 1 at four locations on the traveling frame (vehicle body) 202: the left front end, right front end, left rear end, and right rear end, via vertical rotating shafts 203 and axle cases 204. In other words, the work vehicle 200 is equipped with four omnidirectional wheels 1.

[0205] All four omnidirectional wheels 1 of the work vehicle 200 are drive wheels. Each omnidirectional wheel 1 can rotate as the axle case 204 rotates around the vertical axis of the rotating shaft 203. The work vehicle 200 is equipped with four axle drive motors (electric motors) 205 that can rotate in both forward and reverse directions to rotate each of the four omnidirectional wheels 1 (rotation in the wheel rotation direction Cw (rotation direction around the wheel axis Xw) of the omnidirectional wheels 1 in FIG. 1, etc.). Therefore, each wheel of the work vehicle 200 corresponds to both the first wheel 102, which is the omnidirectional wheel 1 of the work vehicle 100, and the second wheel 103, which is the drive wheel.

[0206] These axle drive motors 205 are housed in the respective axle cases 204 and rotate the omnidirectional wheels 1. That is, in the third embodiment, the omnidirectional wheels 1 are not provided with the hubs 2 and bearings 3, and the wheel members 4 are attached to the drive shafts 205a of the axle drive motors 205. That is, the rotation shaft of the omnidirectional wheel 1 in the third embodiment is the drive shaft 205a of the axle drive motors 205. That is, the output of the axle drive motors 205 rotates the drive shaft 205a, which is the rotation shaft of the omnidirectional wheel 1.

[0207] The axle drive motor 205 may be an electric motor with a gear. In this case, the axle, which is the rotation axis of the omni-directional wheel 1, and the drive shaft 205a of the axle drive motor 205 may be connected via a gear.

[0208] A control device 210 is housed in the main body case 201, and the control device 210 controls the rotation direction and rotation speed of each axle drive motor 205. Therefore, the drive device of the work vehicle 200, which is made up of these four axle drive motors 205, can function as a first body turning device S1 that turns the traveling frame (body) 202 by varying the rotation speed and / or rotation direction of the omnidirectional wheel 1 supported on the left part of the traveling frame (body) 202 and the omnidirectional wheel 1 supported on the right part of the traveling frame (body) 202.

[0209] Each omnidirectional wheel 1 can rotate horizontally (left and right) together with its axle case 204 around the rotation shaft 203. In other words, each omnidirectional wheel 1 functions as a steering wheel. A steering actuator (such as an electric motor) may be attached to each rotation shaft 203 to rotate the axle case 204 around the rotation shaft 203. If the control device 210 or the like uses the steering actuator to control the rotation of the omnidirectional wheel 1 around the rotation shaft 203, the steering actuator or the like can function as the second body turning device S2.

[0210] When the multiple axle drive motors 205 function as the first body turning device S1 to change the rotation speed and / or rotation direction of the left and right omnidirectional wheels 1 to turn the running frame (body) 202, or when the steering actuator functions as the second body turning device S2 to turn the omnidirectional wheels 1 as steering wheels to the left and right, the rollers 6, 7 of the omnidirectional wheels 1 that are in contact with the ground rotate in the roller rotation direction Cr, so that the horizontal rotation is smooth and the work vehicle 200, which is a rover, can smoothly change its traveling direction.

[0211] Furthermore, it is desirable for a rover, which is an exploration vehicle, to have high traction capability when traveling in any direction, and the work vehicle 200, which has four omnidirectional wheels 1, can be provided as a rover with such high traction capability.

[0212] In the work vehicle 200, which is a rover, at least one of the four wheels (for example, only the left and right front wheels, or only the left and right rear wheels) may be a unidirectional wheel rather than an omnidirectional wheel 1. Alternatively, the work vehicle 200 may be provided with a device that switches the stopper 10 provided on each omnidirectional wheel 1 between a stopper release position P1 and a stopper engagement position P2, and the omnidirectional wheel 1 may be configured to act as a unidirectional wheel only at that time by switching the stopper 10 to the stopper engagement position P2.

[0213] The functions and effects of each configuration of the omnidirectional wheel 1 and work vehicles 100, 200 described above will be described below.

[0214] (Item A1) The omnidirectional wheel 1 comprises a rotating shaft (hub) 2, a wheel member 4 arranged around the rotating shaft 2, a plurality of brackets 5 arranged at intervals on the outer periphery of the wheel member 4, a plurality of first rollers 6 rotatably supported on both sides (support portions 5a) of the bracket 5, and a plurality of second rollers 7 arranged between the first rollers 6 and rotatably supported on the bracket 5.

[0215] With the above configuration, the bracket 5 supports both the first roller 6 and the second roller 7, thereby reducing the number of brackets 5 in the omnidirectional wheel 1 and contributing to a reduction in the manufacturing cost of the omnidirectional wheel 1. Furthermore, the bracket 5 supports both the first roller 6 and the second roller 7 on both sides (support portions 5a) and does not support the rollers 6, 7 in the center, so the center portion can be made thin. Therefore, the bracket 5 can be made of a lightweight, compact, and simply structured member, and can be easily attached to the wheel member 4, contributing to a simplification of the assembly process.

[0216] (Item A2) An omnidirectional wheel 1 described in item A1, in which both ends (support portions 5a) of the second roller 7 are each located inside the first roller 6 on the corresponding side and supported by the bracket 5 on the corresponding side.

[0217] With the above configuration, the bracket 5 can support the first roller 6 and the second roller 7 in close proximity, allowing the central portion to be made thinner. Therefore, the bracket 5 can be made of lightweight, compact, and simply structured components, and it can be easily attached to the wheel member 4, contributing to a simplification of the assembly process.

[0218] (Item A3) The omnidirectional wheel 1 described in item A1 or A2, in which the first roller 6 is an annular member and is fitted externally to both sides (support portions 5a) of the bracket 5 so as to be rotatable relative to the bracket 5.

[0219] The above configuration simplifies the support structure for the first roller 6 on the bracket 5, contributing to cost reduction of the omnidirectional wheel 1 due to the simplified structure of the bracket 5 and the first roller 6. Furthermore, by shortening the central axis of the first roller 6, which is an annular member, in combination with the ability to form the bracket 5 into a thin plate as described above, the axial width of the unit roller assembly R, which is made up of the bracket 5 and the pair of first rollers 6 supported on both sides of it, can be reduced. This increases the gap between the first rollers 6 for arranging the second rollers 7, allowing the axial length of the second rollers 7 to be increased, and for example, the diameter of the maximum diameter portion of the middle portion 7a of the barrel-shaped second roller 7 can be increased. Therefore, when the omnidirectional wheel 1 is used as a vehicle wheel, the traction force of the second rollers 7 can be improved.

[0220] (Item A4) The omnidirectional wheel (1) according to any one of items (A1) to (A3), wherein the bracket (5) supports at least four rollers including the first roller (6) and the second roller (7).

[0221] With the above configuration, one bracket 5 supports at least four rollers, which reduces the number of brackets 5 and contributes to reducing the cost of the omnidirectional wheel 1.

[0222] (Item A5) The omnidirectional wheel 1 described in item A4, wherein the second roller 7 has a pair of roller center shafts 8a protruding from both ends in a direction generally along the outer circumferential edge, and the roller center shafts 8a are supported by the bracket 5.

[0223] With the above configuration, each second roller 7 is supported at both ends by a pair of brackets 5 via a pair of roller central shafts 8a. Because each bracket 5 only needs to support one end of the second roller 7 via the roller central shaft 8a, it can be configured using simple, lightweight members, which also contributes to cost reduction.

[0224] (Item A6) The omnidirectional wheel 1 described in item A5, in which the bracket 5 has recesses 5c on both sides (support portions 5a), and the roller central shaft 8a is fitted into the recesses 5c so as to be rotatable relative to the bracket 5 and is supported by the bracket 5.

[0225] With the above configuration, each second roller 7 is supported at both ends by the pair of brackets 5 via the pair of roller central shafts 8a. In order to support one end of the second roller 7, it is only necessary to form a recess 5c in the bracket 5 into which the roller central shaft 8a is fitted. Therefore, the bracket 5 can be made of a simple, lightweight member, which also contributes to cost reduction.

[0226] (Item A7) The omnidirectional wheel 1 according to any one of items A1 to A6, wherein a plurality of first lugs 6a are arranged on the outer peripheral edge of the first roller 6 radially around the center line of the first roller 6 in the direction along the outer peripheral edge, and a plurality of second lugs 7a are arranged on the outer peripheral edge of the second roller 7 so as to extend circumferentially around the center line of the second roller 7 in the direction along the outer peripheral edge.

[0227] With the above configuration, the radial first lugs 6a of the first roller 6 pierce the soil in a point-like manner, and the circumferential second lugs 7a of the second roller 7 pierce the soil in a line-like manner. In this way, by combining lugs 6a, 7a with different piercing patterns on the omnidirectional wheel 1, the traction force of the omnidirectional wheel 1 can be increased.

[0228] (Item A8) A work vehicle (100, 200) comprising an omnidirectional wheel (1) according to any one of items A1 to A7, and a vehicle body (101, 202) that supports the rotation shaft (2) of the omnidirectional wheel (1) so that it can rotate freely.

[0229] With the above configuration, work vehicles 100, 200 with excellent turning maneuverability can be provided at low cost by including omnidirectional wheels 1 having rollers 6, 7 that are rotatable in a roller rotation direction Cr that is different from the wheel rotation direction Cw.

[0230] (Item B1) An omnidirectional wheel (1) comprising a rotating shaft (2), a wheel member (4) arranged around the rotating shaft (2), a plurality of rollers (6, 7) supported on the outer periphery of the wheel member (4) so ​​as to be rotatable in a direction different from the rotation direction of the wheel member (4), and a stopper (10), wherein at least one of the plurality of rollers (6, 7) has a hook portion (6a) that can abut against the stopper (10).

[0231] With the above configuration, when it is desired to rotate omnidirectional wheel 1 only in the normal wheel rotation direction (wheel rotation direction Cw) around rotation axis 2 (wheel axis center Xw) and not in the roller rotation direction, stopper 10 and hook portion 6a cooperate to prevent rotation in the roller rotation direction. Here, because the structure for preventing roller rotation (hook portion 6a) is provided on the roller rather than stopper 10, the stopper 10 can be configured simply and at low cost.

[0232] (Item B2) The omnidirectional wheel 1 according to item B1, wherein the hook portion 6a abuts against the stopper 10 to suppress at least one of rotation of one side and rotation of the other side of the roller.

[0233] With the above configuration, hook portion 6a only needs to restrain rotation of one side or the other side of the roller by abutting against stopper 10. Therefore, compared to a configuration in which a stopper configured like a brake shoe is pressed against the outer circumferential surface of the roller to restrain rotation of the roller in both directions, the contact area between hook portion 6a and stopper 10 to restrain roller rotation can be smaller, and the structure for restraining roller rotation can be simplified.

[0234] (Item B3) The omnidirectional wheel 1 described in item B1 or B2, wherein, of the plurality of rollers 6, 7, at least one roller having the hook portion 6a is a first roller 6, and the hook portion 6a is a plurality of protrusions 6a1, 6a2 that protrude from the outer peripheral surface of the first roller 6 and can abut against the stopper 10 on one side and the other side in the rotation direction of the first roller 6.

[0235] The multiple protrusions 6a1, 6a2 of the first roller 6 can be used as hooks that can restrain the rotation of the roller by abutting against the stopper 10. If the first roller 6 is a roller with lugs, the lugs 6a can be used as they are as the multiple protrusions 6a1, 6a2. In other words, since there is no need to process the roller to provide the hooks, an omnidirectional wheel 1 that can restrain the rotation of the roller in the rotational direction can be provided at low cost.

[0236] (Item B4) The omnidirectional wheel 1 according to item B3, wherein the stopper 10 is capable of entering a gap 6s between two adjacent protrusions 6a1, 6a2.

[0237] With the above configuration, stopper 10 can be prevented from rotating the roller of omnidirectional wheel 1 by simply inserting stopper 10 into gap 6s between protrusions 6a1, 6a2. Because stopper 10 does not require a biasing means or the like that is required when a brake shoe is configured to press against the outer circumferential surface of the roller, the configuration of stopper 10 can be simplified.

[0238] (Item B5) The omnidirectional wheel 1 according to item B4, wherein the stopper 10 is a disc-shaped member.

[0239] With the above-described configuration, the stopper 10 can be made of low-cost members with a simple shape.

[0240] (Item B6) The omnidirectional wheel 1 described in item B3 or B4 is switchable between a first position P1 where the stopper 10 does not come into contact with the protrusions 6a1, 6a2 and allows the first roller 6 to rotate, and a second position P2 where the stopper 10 comes into contact with the protrusions 6a1, 6a2 and restricts the rotation of the first roller 6.

[0241] With the above configuration, by simply changing the position of the stopper 10, the omnidirectional wheel 1 can be switched between a state in which the rotation of the first roller 6 is permitted and a state in which the rotation of the first roller 6 is restricted.

[0242] (Item B7) The omnidirectional wheel 1 according to item B6, wherein the outer peripheral edge portion of the stopper 10 at the first position P1 is not located in the gap 6s between the two adjacent protrusions 6a1, 6a2, and the outer peripheral edge portion of the stopper 10 at the second position P2 is located in the gap 6s.

[0243] With the above configuration, changing the position of the stopper 10 between the first position P1 and the second position P2 is based on the simple operation of whether or not to insert the stopper 10 into the gap 6s. Therefore, the configuration for changing the position of the stopper 10 is simple.

[0244] (Item B8) The omnidirectional wheel (1) according to item (B7), wherein the stopper (10) is switched between the first position (P1) and the second position (P2) by moving forward and backward in a direction along the rotation shaft (2).

[0245] With the above configuration, the position of the stopper 10 can be changed between the first position P1 and the second position P2 by a simple operation of moving the stopper 10 back and forth in a direction along the rotation shaft 2. Therefore, the configuration for changing the position of the stopper 10 is simple.

[0246] (Item B9) The omnidirectional wheel (1) according to item (B5), wherein the outer peripheral edge of the stopper (10) abuts against the protrusions (6a1, 6a2) to restrict the rotation of the first roller (6).

[0247] With the above-described configuration, the portion of the stopper 10 that comes into contact with the protruding portions 6a1 and 6a2 of the roller 6 is only the outer peripheral edge portion, which leads to a reduction in size and simplification of the stopper 10.

[0248] (Item B10) The omnidirectional wheel 1 according to any one of items B3 to B9, wherein the plurality of rollers 6, 7 includes a second roller 7 in addition to the first roller 6, and the stopper 10 is capable of entering a gap 6s between two adjacent protrusions 6a1, 6a2 of the first roller 6.

[0249] With the above configuration, while the omnidirectional wheel 1 includes separate first and second rollers 6 and 7, the gap 6s between the protrusions 6a1 and 6a2 of the first roller 6, into which the stopper 10 can enter, can be used to suppress rotation of the first roller 6, while there is no need to consider suppressing rotation of the second roller 7. This simplifies the configuration of the stopper 10.

[0250] (Item B11) The omnidirectional wheel (1) according to item (B10), wherein the second roller (7) has a different shape from the first roller (6).

[0251] With the above configuration, the omnidirectional wheel 1 includes the first roller 6 and the second roller 7, which have different shapes. While the stopper 10 can suppress the rotation of the first roller 6, it is not necessary to consider suppressing the rotation of the second roller 7. Therefore, the configuration of the stopper 10 can be simplified.

[0252] (Item B12) The omnidirectional wheel 1 according to item B10 or B11, wherein the second roller 7 is arranged between at least two of the first rollers 6 along the outer periphery of the wheel member 4 centered on the rotation axis 2.

[0253] With the above configuration, when the second rollers 7 are arranged between the first rollers 6 of the omnidirectional wheel 1, the stopper 10 can suppress the rotation of the first rollers 6, but does not need to consider suppressing the rotation of the second rollers 7. This simplifies the configuration of the stopper 10.

[0254] (Item B13) The omnidirectional wheel 1 described in any one of items B3 to B10, wherein the plurality of rollers 6, 7 includes a second roller 7 in addition to the first roller 6, and the outer peripheral edge portion of the stopper 10 abuts against the protrusions 6a1, 6a2 to regulate the rotation of the first roller 6.

[0255] With the above configuration, while the omnidirectional wheel 1 includes separate first and second rollers 6 and 7, the rotation of the first roller 6 can be suppressed by the contact between the outer peripheral edge of the stopper 10 and the protrusions 6a1 and 6a2 of the first roller 6, while there is no need to consider suppressing the rotation of the second roller 7. This simplifies the configuration of the stopper 10.

[0256] (Item B14) The omnidirectional wheel (1) according to item (B13), wherein the second roller (7) has a different shape from the first roller (6).

[0257] With the above configuration, the omnidirectional wheel 1 includes the first roller 6 and the second roller 7, which have different shapes. While the stopper 10 can suppress the rotation of the first roller 6, it is not necessary to consider suppressing the rotation of the second roller 7. Therefore, the configuration of the stopper 10 can be simplified.

[0258] (Item B15) The omnidirectional wheel 1 according to item B13 or B14, wherein the second roller 7 is arranged between at least two of the first rollers 6 along the outer periphery of the wheel member 4 centered on the rotation axis 2.

[0259] With the above configuration, when the second rollers 7 are arranged between the first rollers 6 of the omnidirectional wheel 1, the stopper 10 can suppress the rotation of the first rollers 6, but does not need to consider suppressing the rotation of the second rollers 7. This simplifies the configuration of the stopper 10.

[0260] (Item B16) The omnidirectional wheel 1 described in item B5, wherein the plurality of rollers 6, 7 include two of the first rollers 6 arranged point-symmetrically around the rotation axis 2, and the diameter L4 of the stopper 10 is shorter than the distance L3 between the rotation center lines Xr1 of the two first rollers 6 arranged point-symmetrically.

[0261] With the above configuration, the stopper 10 can be made smaller.

[0262] (Item B17) A work vehicle (100, 200) comprising an omnidirectional wheel (1) according to any one of items B1 to B16, and a vehicle body (101, 202) that supports the rotation shaft (2) of the omnidirectional wheel (1) so that it can rotate freely.

[0263] With the above configuration, it is possible to provide a work vehicle 100, 200 that is equipped with an omnidirectional wheel 1 with a stopper 10 and that can easily switch the omnidirectional wheel 1 between a unidirectional wheel state and an omnidirectional wheel state.

[0264] (Item C1) A work vehicle 100, 200 includes a vehicle body 101, 202, first wheels 102 which are left and right omnidirectional wheels 1 supported on both the left and right sides of the vehicle body 101, a drive unit 105, and left and right second wheels 103 which are drive wheels supported in front of or behind the first wheels 102 on both the left and right sides of the vehicle body 101, 202 and driven by the drive unit 105.

[0265] With the above configuration, it is possible to make use of the performance of the omnidirectional wheels 1 to configure a work vehicle 100 (tractor), 200 (rover) with excellent turning ability.

[0266] (Item C2) The work vehicle (100, 200) according to item C1, wherein the second wheel (103) is a unidirectional wheel that can rotate in one direction.

[0267] With the above configuration, the work vehicles 100, 200 can be configured to travel stably by rotating the second wheel 103, which is a unidirectional wheel, in the direction of travel.

[0268] (Item C3) The work vehicle 100, 200 described in item C1 or C2, wherein the omnidirectional wheel 1 is a wheel that can rotate in a first direction (wheel rotation direction Cw) and a second direction (roller rotation direction Cr) perpendicular to the first direction.

[0269] With the above configuration, even if the vehicle body 101, 202 moves in a second direction (roller rotation direction Cr) different from the first direction (wheel rotation direction Cw), the omnidirectional wheel 1 can rotate in the second direction, allowing the vehicle body 101 to move smoothly.

[0270] (Item C4) The work vehicle 100, 200 described in any one of items C1 to C3, wherein the omnidirectional wheel 1 comprises a rotating shaft (hub) 2, a wheel member 4 arranged around the rotating shaft 2, a plurality of first rollers 6 supported at intervals on the outer circumferential edge of the wheel member 4 so as to be rotatable in a direction different from the rotation direction of the wheel member 4, and a plurality of second rollers 7 rotatably arranged between the first rollers 6.

[0271] The above configuration allows the wheel member 4 to rotate in the normal wheel rotation direction Cw, and the first roller 6 and second roller 7 to rotate in a roller rotation direction Cr different from the wheel rotation direction Cw.

[0272] (Item C5) The work vehicle 100, 200 according to any one of items C1 to C4, wherein the first wheel 102 is a front wheel and the second wheel 103 is a rear wheel.

[0273] With the above configuration, the front wheels of the work vehicles 100, 200, which have rear drive wheels, become omnidirectional wheels 1, ensuring excellent turning performance and wheel traction in a direction different from the wheel rotation direction Cw.

[0274] (Item C6) The work vehicle 100, 200 is described in any one of items C3 to C5, wherein the first wheel 102, which is the omnidirectional wheel 1, has a plurality of rollers 6, 7 whose rotation direction is the second direction (roller rotation direction Cr (direction along roller circumferential lines Cr1, Cr2)), and is equipped with a first body turning device S1 (drive device 105) that turns the body 101 by making the rotation speed or rotation direction of the left and right second wheels 103 different from each other, and wherein, while the body 101 is turning by the first body turning device S1, the rollers 6, 7 of the first wheel 102 that are in contact with the ground can rotate in the second direction (roller rotation direction Cr).

[0275] With the above configuration, when the first body turning device S1 functions to turn the vehicle by differential (in rotation speed and / or rotation direction) of the left and right second wheels 103, when the body 101 moves in a direction different from the wheel rotation direction Cw and stress or load is applied to the first wheel 102 in that direction, the rollers 6, 7 rotate correspondingly, thereby allowing the body 101, 202 to turn smoothly in that direction.

[0276] (Item C7) The work vehicle 100, 200 described in item C6, wherein the drive device 105 is capable of driving the left and right second wheels 103 at different rotational speeds and / or rotational directions, and the drive device 105 functions as the first body turning device S1.

[0277] With the above configuration, the drive device 105 functions as the first body turning device S1 by utilizing the structure that allows the drive device 105 to drive the left and right second wheels 103 at different rotational speeds and / or rotational directions. Therefore, there is no need to add a new device as the first body turning device S1, and it is possible to reduce the number of components of the work vehicles 100, 200 and to reduce costs.

[0278] (Item C8) The left and right first wheels 102 and / or the left and right second wheels 103 are steering wheels whose angle in the left-right direction relative to the vehicle body 101, 202 can be changed, and the work vehicle 100, 200 described in item C6 or C7 is equipped with a steering device 120 as a second vehicle body turning device S2 that turns the vehicle body 101, 202 by changing the angle in the left-right direction of the steering wheels relative to the vehicle body 101, 202.

[0279] With the above configuration, work vehicles 100, 200 can be configured to simultaneously execute the turning of the vehicle bodies 101, 202 by having the drive device 105 etc. function as the first vehicle body turning device S1 and the turning of the vehicle bodies 101, 202 by having the steering device 120 function as the second vehicle body turning device S2 so as to assist each other. Also, work vehicles 100, 200 can be configured to select whether to turn the vehicle bodies 101, 202 by the first vehicle body turning device S1 or the second vehicle body turning device S2.

[0280] (Item C9) The left and right first wheels 102 and / or the left and right second wheels 103 are steering wheels whose angle in the left and right direction relative to the vehicle body 101, 202 can be changed, and the work vehicle 100, 200 described in any of items C1 to C7 is equipped with a steering device 120 that turns the vehicle body by changing the angle in the left and right direction of the steering wheels relative to the vehicle body 101, 202.

[0281] With the above configuration, the vehicle bodies 101, 202 can be turned by steering the steering wheels using the steering device 120. When the vehicle body turns, the rollers 6, 7 in the omnidirectional wheel 1 that are in contact with the ground rotate in a direction substantially along the turning direction of the vehicle body 101, 202, making the turn smooth.

[0282] (Item C10) The work vehicle 100, 200 according to any one of items C1 to C9, wherein the second wheel 103 is an omnidirectional wheel 1.

[0283] The above configuration makes it possible to provide work vehicles 100, 200 in which all wheels are omnidirectional wheels and the effect of this function (ability to rotate in both the first and second directions) can be enjoyed by all wheels (both front and rear wheels).

[0284] Although the embodiments of the present invention have been described above, the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0285] 1: Omnidirectional wheels 2: Rotating shaft (hub) 4: Wheel parts 5: Bracket 5a: Support part 5c: Recess 6: First roller (roller) 6a: First lug 7: Second roller (roller) 7a: Second lug (middle) 8a: Roller central axis 100: Work vehicle (tractor) 101: Body 200: Work vehicle (Rover) 202: Body (running frame) Cr: Roller rotation direction Cw: Wheel rotation direction R: Unit roller assembly

Claims

1. A rotation axis; a wheel member provided around the rotation shaft; a plurality of brackets spaced apart from one another on the outer periphery of the wheel member; a plurality of first rollers rotatably supported on both sides of the bracket; a plurality of second rollers disposed between the first rollers and rotatably supported by the bracket; Equipped with omnidirectional wheels.

2. 2. The omnidirectional wheel according to claim 1, wherein both ends of the second roller are located inside the corresponding first roller and supported by the corresponding bracket.

3. 3. The omnidirectional wheel according to claim 1, wherein the first rollers are annular members fitted onto both sides of the bracket so as to be rotatable relative to the bracket.

4. 3. The omni-directional wheel according to claim 1, wherein the bracket supports at least four rollers, including the first roller and the second roller.

5. the second roller has a pair of roller center shafts that protrude from both ends in a direction substantially along the outer circumferential edge, 5. The omnidirectional wheel according to claim 4, wherein the roller central shaft is supported by the bracket.

6. The bracket has recesses on both sides, 6. The omnidirectional wheel according to claim 5, wherein the roller center shaft is fitted into the recess so as to be relatively rotatable and is supported by the bracket.

7. a plurality of first lugs disposed on an outer circumferential edge of the first roller radially around a centerline of the first roller in a direction along the outer circumferential edge; 3. The omnidirectional wheel according to claim 1, wherein a second lug is provided on the outer circumferential edge of the second roller so as to extend circumferentially around the centerline of the second roller in a direction along the outer circumferential edge.

8. an omnidirectional wheel according to claim 1 or 2; a vehicle body that rotatably supports the rotation shaft of the omnidirectional wheel; A work vehicle equipped with

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