Omnidirectional wheel and work vehicle provided with same

Abstract

The present invention provides an omnidirectional wheel that has traversing force in a direction different from an advancing direction, and is suitable as a wheel for a work vehicle.　An omnidirectional wheel (1) comprises: a wheel member (20); and rollers (40) that are rotatably supported along an outer peripheral portion (21) of the wheel member (20) in a second rotation direction (Cr) intersecting a first rotation direction (Cw), which is the rotation direction of the wheel member (20). The rollers (40) have protruding portions (45) that protrude from the outer peripheral portion of the rollers (40) so as to resist the rotation of the rollers (40) in the second rotation direction Cr.

Description

Omnidirectional wheel and work vehicle equipped with same

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

[0002] Conventionally, omnidirectional wheels have been known, such as those described in Patent Documents 1 and 2, which are configured with multiple rollers arranged circumferentially around the wheel, rotating in a lateral direction that intersects with the vehicle's straight-ahead direction.

[0003] When an omnidirectional wheel receives a force or load in a direction that crosses the direction of rotation of the wheel, a normal wheel would slip.However, the rollers of an omnidirectional wheel rotate in the direction of the force or load, so the wheel does not slip and is less likely to wear out.

[0004] Japanese Patent Publication "Patent No. 3682248" Japanese Patent Publication "Patent No. 5994175"

[0005] As an example of a vehicle equipped with omnidirectional wheels as described in Patent Documents 1 and 2, consider a case in which a tractor equipped with omnidirectional wheels is performing agricultural work in a field with soft soil. The wheels are driven to rotate by the power of a prime mover, and the direction of rotation can be changed by steering or switching between forward and reverse. When the tractor makes a sharp turn in the field, the wheels are subjected to forces and loads in a direction different from the direction of rotation, such as a direction intersecting (perpendicular to) the direction of rotation. However, the rollers rotate in that direction, preventing the wheels from skidding.

[0006] However, if the soil in the field is soft or the ground is uneven and uneven, the rollers will rotate while buried in the soil, which could cause the wheels to become stuck. While it would be possible to provide a means for providing grip on the soil and making it easier to escape from a stuck state, conventional omnidirectional wheels were not envisioned for use in situations where the rollers might become stuck, and Patent Documents 1 and 2 do not disclose or suggest such a means.

[0007] The present invention has been made to solve the problems of the prior art, and has as its object to provide an omnidirectional wheel suitable for use as a wheel on a work vehicle such as an agricultural tractor, and a work vehicle equipped with the same.

[0008] An omnidirectional wheel according to one embodiment of the present invention comprises a wheel member and a roller rotatably supported along the outer periphery of the wheel member in a second rotational direction that intersects a first rotational direction, which is the rotational direction of the wheel member, and the roller has a protrusion that protrudes from the outer periphery of the roller to resist rotation of the roller in the second rotational direction.

[0009] The roller may have a plurality of the protrusions, which may protrude radially from the outer periphery of the roller around the axis of the roller and be arranged in the second rotation direction.

[0010] The roller may have a shape whose diameter changes as it moves in the axial direction of the roller, and the protrusion may protrude from at least a portion of the outer periphery of the roller where the diameter is greatest.

[0011] The roller may have a first end and a second end that face each other in the axial direction of the roller, the diameter of the first end being larger than the diameter of the second end, and the protrusion may protrude beyond the outer periphery of at least the first end of the first and second ends.

[0012] The roller may have a shape that gradually reduces in diameter as it moves axially from the first end to the second end.

[0013] A plurality of the rollers may be arranged along the outer periphery of the wheel member in the first rotation direction.

[0014] The omnidirectional wheel may include a bracket attached to the outer periphery of the wheel member and supporting at least two of the plurality of rollers, and the at least two rollers supported by the bracket may include a first roller arranged on one side of the bracket and a second roller arranged on the other side of the bracket in the first rotational direction.

[0015] The bracket may have a roller insertion recess that opens on one side in the first rotation direction and a convex portion that protrudes on the other side, and each of the plurality of rollers may have a first end on the one side, a second end on the other side, and a bracket insertion recess that opens at the first end, and the second end of the first roller may be inserted into the roller insertion recess of the bracket, and the convex portion of the bracket may be inserted into the bracket insertion recess of the second roller.

[0016] The omnidirectional wheel may include brackets attached to the outer periphery of the wheel member and supporting the rollers, and a plurality of the brackets may be arranged along the outer periphery of the wheel member in the first rotational direction, and the plurality of brackets may include a first bracket supporting the rollers on one side and a second bracket supporting the rollers on the other side in the first rotational direction.

[0017] The protrusion has a first side surface facing the one side, a second side surface facing the other side, and an apex surface extending between the first side surface and the second side surface at a radial apex from the axis of the roller, and when the protrusion reaches a position where the apex surface faces the wheel member in the gap between the first bracket and the second bracket due to rotation of the roller in the second rotational direction, the first side surface faces the first bracket and the second side surface faces the second bracket.

[0018] A work vehicle according to one embodiment of the present invention may include the omnidirectional wheel, an axle connected to the wheel member of the omnidirectional wheel, and a vehicle body that rotatably supports the axle.

[0019] The omnidirectional wheels according to the present invention provide excellent traction even when the rollers rotate on soft soil, enabling a work vehicle equipped with omnidirectional wheels to perform work efficiently.

[0020] 1 is a perspective view of the omnidirectional wheel according to the first embodiment when the stopper is released. FIG. 2 is an outer side view of the omnidirectional wheel according to the first embodiment. FIG. 3 is an inner side view of the omnidirectional wheel according to the first embodiment. FIG. 4 is a partially enlarged outer side view of the omnidirectional wheel according to the first embodiment with the stopper and retaining plate removed. FIG. 5 is an outer side cross-sectional view of the omnidirectional wheel according to the first embodiment. FIG. 6 is a partially enlarged outer side cross-sectional view of the omnidirectional wheel according to the first embodiment, showing the combined roller and its periphery. FIG. 7 is a partially enlarged front cross-sectional view of the omnidirectional wheel according to the first embodiment, showing the engagement state between the bracket and the wheel member. FIG. 8 is a partially enlarged front cross-sectional view of the omnidirectional wheel according to the first embodiment, showing the engagement state between the bracket and the wheel member according to a modified example. FIG. 9 is a front cross-sectional view of the omnidirectional wheel according to the first embodiment, showing the positional relationship between the stopper and the roller when the stopper is released. FIG. 10 is a perspective view of the omnidirectional wheel according to the first embodiment when the stopper is actuated. FIG. 11 is a front cross-sectional view of the omnidirectional wheel according to the first embodiment, showing the positional relationship between the stopper and the roller when the stopper is actuated. FIG. 12 is a schematic front cross-sectional view of the omnidirectional wheel according to the first embodiment connected to the axle case of a work vehicle. FIG. 13 is an exploded perspective view of the omnidirectional wheel according to the first embodiment when the first roller and the second roller are assembled. 1 is a perspective view of the omnidirectional wheel according to the first embodiment when the first roller is assembled; FIG. 2 is an exploded perspective view of the omnidirectional wheel according to the first embodiment when a combined roller is assembled as the last roller; FIG. 3 is an exploded perspective view of the omnidirectional wheel according to the first embodiment when a combined roller is assembled alone; FIG. 4 is a perspective view of the omnidirectional wheel according to the second embodiment; FIG. 5 is an outer side view of the omnidirectional wheel according to the second embodiment; FIG. 6 is an inner side view of the omnidirectional wheel according to the second embodiment; FIG. 7 is a side cross-sectional view of the omnidirectional wheel according to the second embodiment; FIG. 8 is a front cross-sectional view of the omnidirectional wheel according to the second embodiment when the stopper is released; FIG. 9 is a front cross-sectional view of the omnidirectional wheel according to the second embodiment showing the stopper in the stopper release position; FIG. 10 is a front cross-sectional view of the omnidirectional wheel according to the second embodiment when the stopper is actuated; FIG. 11 is a front cross-sectional view of the omnidirectional wheel according to the second embodiment when the stopper is actuated by a stopper of a different configuration; FIG. 12 is a perspective view of the omnidirectional wheel according to the second embodiment with the stopper removed.1 is a perspective view of a wheel member of an omnidirectional wheel according to a second embodiment with a unit roller assembly installed; FIG. 2 is an exploded perspective view showing a state in which a first roller has been removed from a bracket attached to the wheel member of an omnidirectional wheel according to a second embodiment; FIG. 3 is a perspective view of a wheel member of an omnidirectional wheel according to a second embodiment with a unit roller assembly and a second roller installed; FIG. 4 is an outer side view of a wheel member of an omnidirectional wheel according to a second embodiment with a unit roller assembly and a second roller installed; FIG. 5 is an exploded perspective view of an omnidirectional wheel according to a second embodiment with a first roller and a second roller removed from a bracket attached to the wheel member; FIG. 6 is an exploded side view of an omnidirectional wheel according to a second embodiment with a first roller and a second roller removed from a bracket attached to the wheel member; FIG. 7 is a perspective view showing a tractor according to a third embodiment, which is an example of a work vehicle equipped with omnidirectional wheels, during a pivot turn; FIG. 8 is a side view of a tractor according to a third embodiment, which is an example of a work vehicle equipped with omnidirectional wheels; FIG. 9 is a diagram showing the structure of a drive / steering system of a work vehicle according to a third embodiment; FIG. 10 is a diagram showing the structure of a drive system of a work vehicle according to a fourth embodiment; FIG. 11 is a perspective view of a rover according to a fifth embodiment, which is another example of a work vehicle equipped with omnidirectional wheels.

[0021] [Omnidirectional Wheel According to First Embodiment] Hereinafter, an omnidirectional wheel 50 according to a first embodiment will be described with reference to the accompanying Figs. 1 to 16.

[0022] Figure 1 is a perspective view of the omnidirectional wheel 50 when the stopper 60 is released. Figure 2 is an outer side view of the omnidirectional wheel 50. Figure 3 is an inner side view of the omnidirectional wheel 50. Figure 4 is a partially enlarged outer side view of the omnidirectional wheel 50 with the stopper 60 and retaining plate 61 removed.

[0023] Fig. 5 is a cross-sectional view of the outer side of omni-directional wheel 50. Fig. 6 is a partially enlarged cross-sectional view of the outer side of omni-directional wheel 50 showing combination roller 40H and its surroundings.

[0024] Fig. 7 is a partially enlarged front cross-sectional view of the omnidirectional wheel 50, showing the engagement state between the bracket 30 and the wheel member 20. Fig. 8 is a partially enlarged front cross-sectional view of the omnidirectional wheel 50, showing the engagement state between a bracket 30M and a wheel member 20A according to a modified example.

[0025] Figure 9 is a front cross-sectional view of the omnidirectional wheel 50 showing the positional relationship between the stopper 60 and the roller 40 when the stopper is released. Figure 10 is a perspective view of the omnidirectional wheel 50 when the stopper is activated. Figure 11 is a front cross-sectional view of the omnidirectional wheel 50 showing the positional relationship between the stopper 60 and the roller 40 when the stopper is activated. Figure 12 is a schematic front cross-sectional view of the omnidirectional wheel 50 connected to the axle case 152 of the work vehicle 100.

[0026] 13 is an exploded perspective view of the omnidirectional wheel 50 when the first roller 40 and the second roller 40 are assembled, showing the assembled (disassembled) structure of the omnidirectional wheel 50. FIG. 14 is a perspective view of the omnidirectional wheel 50 when the first roller 40 is assembled. FIG. 15 is an exploded perspective view of the omnidirectional wheel 50 when the combined roller 40H is assembled as the last roller 40. FIG. 16 is an exploded perspective view of the omnidirectional wheel 50 when the combined roller 40H is assembled alone.

[0027] The omnidirectional wheel 50 has a wheel member 20 (see FIGS. 12 to 14, etc.) as a hub attached to an axle 157 (see FIG. 12) supported on the work vehicle 100, as a basic wheel component for being supported as a wheel on the work vehicle 100. The axle 157 and the wheel member 20 are arranged on the same axis and connected so as to be unable to rotate relative to each other.

[0028] Hereinafter, the omnidirectional wheel 50 and the work vehicle 100 will be described, with the axis line of the wheel member 20 and the axle 157 connected to the wheel member 20 referred to as the "wheel axis Xw." The direction K1 in which the wheel axis Xw extends (the direction along the wheel axis Xw) may be referred to as the "wheel axis direction K1" (see FIG. 1, etc.).

[0029] The rotation direction of the wheel member 20 around the wheel axis Xw is the rotation direction of the omnidirectional wheel 50 as a wheel. A circumferential line centered on the wheel axis Xw that defines the rotation direction of the wheel member 20 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 (first rotation direction)" (see FIG. 1, etc.).

[0030] 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 roller circumferential line Cr of the roller 40, which will be described later.

[0031] 7 and other drawings, the wheel member 20 has opposite end faces 25, 26 (surfaces perpendicular to the wheel axis Xw) in the wheel axis direction K1, and when the omnidirectional wheel 50 is attached to a vehicle (work vehicle 100), the end face located closer to the vehicle (inner side K2) is the inner end face 25, and the end face located farther from the vehicle (outer side K3) is the outer end face 26. A stopper 60, which will be described later, and the like are provided on the outer end face 26.

[0032] As can be seen in Figure 14 and other figures, the wheel member 20 has a cylindrical outer circumferential portion 21 that extends in the wheel axial direction K1 around the wheel axis Xw from the inner end surface 25 to the outer end surface 26. Also, as shown in Figures 1 to 6 and other figures, the omnidirectional wheel 50 includes rollers 40 that are supported along the outer circumferential portion 21 of the wheel member 20 so as to be rotatable in a roller rotation direction (second rotation direction) that intersects (is perpendicular to) the wheel rotation direction. Specifically, the rollers 40 are supported by brackets 30 attached to the outer circumferential portion 21 of the wheel member 20.

[0033] 1 to 4, in the omnidirectional wheel 50, a plurality of rollers 40 are arranged in the wheel rotation direction along the outer periphery 21 of the wheel member 20. Furthermore, in the omnidirectional wheel 50, in order to support the plurality of rollers 40, a plurality of brackets 30 are attached to the outer periphery 21 of the wheel member 20 and arranged in the wheel rotation direction (along the wheel circumferential line Cw).

[0034] 5 and 6, each of the rollers 40 has a roller shaft 41 at the position of the roller axis Xr (see FIG. 2) corresponding to the center line of rotation of the roller, and a main body 42 is circumferentially attached to the roller shaft 41. Each roller 40 is supported by the bracket 30 so as to be rotatable in the roller rotation direction along a roller circumference line Cr (see FIG. 1) centered on the roller axis Xr.

[0035] As can be seen from Figure 2, the direction of the roller axis Xr of each roller 40 corresponds to the tangent direction to the wheel circumferential line Cw. Therefore, there is an angle between the roller axis Xr of two adjacent rollers 40 that corresponds to the positional difference between the two rollers 40 in the wheel rotation direction. Hereinafter, this angle between the roller axis Xr will be referred to as the "roller angle θr."

[0036] Each roller 40 has a cylindrical body 42 attached to the roller shaft 41, and a plurality of lugs (protrusions) 45 protruding from the outer periphery of the body 42 are arranged in the direction of roller rotation (along the roller circumference line Cr shown in FIG. 1).

[0037] The above is a general configuration of the omnidirectional wheel 50, which is made up of the wheel member 20, bracket 30, and roller 40. Next, the specific structures of the wheel member 20, bracket 30, and roller 40 will be described in detail.

[0038] First, the specific structure of the wheel member 20 shown in Figures 1 to 16 will be described in detail. The wheel member 20 is a bent cylindrical plate-like member. The wheel member 20 has at least enough strength to rotatably support the roller 40 on the bracket 30 attached to its outer periphery 21. Such a wheel member 20 is made by plastic molding or blow molding of a synthetic resin material, but other configurations are also possible, and the material, configuration, etc. are not limited.

[0039] 7, 9, 11, etc., the wheel member 20 has a flange portion 27 that extends from the outer circumferential portion 21 toward the wheel axis Xw at a position closer to the outer end face 26 in the wheel axis direction K1. The wheel member 20 has an inner cavity surrounded by the outer circumferential portion 21. As shown in Figure 7, etc., the inner cavity of the wheel member 20 is partitioned by the flange portion 27 into an inner cavity 28 from the flange portion 27 to the inner end face 25, and an outer cavity 29 from the flange portion 27 to the outer end face 26.

[0040] Since the flange portion 27 is positioned closer to the outer end 26 in the wheel axis direction K1, the inner bore 28 is longer in the wheel axis direction K1 than the outer bore 29 and is therefore wider.

[0041] As shown in Figure 12, the axle 157 supported on the body 101 of the work vehicle 100 (via the axle case 152) is inserted into the inner bore 28 through the opening in the inner end surface 25 of the wheel member 20, and the tip of the axle 157 is attached and fixed to the flange portion 27 by bolting or the like, thereby fixing it to the wheel member 20.

[0042] As shown in Figures 7 and 14, a groove 23 is formed in the outer circumferential portion 21 of the wheel member 20, extending in the wheel axis direction K1 from the inner end surface 25 to the outer end surface 26. The groove 23 opens radially outward of the wheel member 20. As shown in Figures 6 and 7, a base end portion 31a of a bracket 30 is fitted into the groove 23. Therefore, the wheel member 20 is provided with a plurality of grooves 23, the same number as the number of brackets 30, arranged at approximately equal intervals along the wheel circumferential line Cw.

[0043] 7 and 14 , the groove 23 has a bottom end surface formed at a constant depth in the radial direction of the wheel member 20 over the entire area in the wheel axis direction K1 from the inner end surface 25 to the outer end surface 26. This bottom end surface serves as a contact portion 24 that comes into contact with the base end portion 31 a of the bracket 30 fitted into the groove 23 at the outer circumferential portion 21 of the wheel member 20.

[0044] The outer peripheral portion 21 of the wheel member 20, except for the contact portion 24 (including the inner surface of the groove 23), is a curved plate portion 22 that is bent so that the diameter changes as it moves in the wheel axis direction K1. In this embodiment, the curved plate portion 22 is curved in an arc shape in the wheel axis direction K1.

[0045] The contact portion 24 is the bottom end surface of a groove 23 of a constant depth in the radial direction of the wheel member 20 over the entire area in the wheel axis direction K1, and is therefore bent along the curved plate portion 22 in the wheel axis direction K1.

[0046] That is, the contact portion 24 is bent along the curved plate portion 22 so that the radial position of the wheel member 20 changes as the contact portion 24 moves in the wheel axis direction K1. The base end portion 31 a of the bracket 30 that is fitted into the groove 23 is bent in accordance with (along with) the bending of the contact portion 24 so that the base end portion 31 a can maintain contact with the contact portion 24 of the wheel member 20 without separating from the contact portion 24.

[0047] In this way, the difference in position in the wheel axis direction K1 changes the position in the radial direction of the wheel member 20 of the part where the contact portion 24 of the wheel member 20 and the base end portion 31 a of the bracket 30 come into contact. This ensures that the contact portion 24 and the base end portion 31 a of the bracket 30 are firmly engaged, preventing the bracket 30 from moving from its fixed position in the wheel axis direction K1 and coming off the wheel member 20.

[0048] In addition, in order to prevent the bracket 30 from coming off the wheel member 20 or from shifting in position in the wheel axis direction K1, it is not necessary for the contact portion 24 to be bent so that the diameter changes over the entire area in the wheel axis direction K1; it is sufficient that at least one part of the contact portion 24 that is positioned differently in the wheel axis direction K1 and the other part are positioned differently in the radial direction of the wheel member 20.

[0049] For example, as shown in Figure 8, in wheel member 20A, which is a modified example of wheel member 20, contact portion 24A, which is the bottom end surface of groove 23A, has a step 24Aa (a portion extending radially of wheel member 20) at one point midway in the wheel axis direction K1, and the radial positions of a first portion 24Ab extending from step 24Aa to the inner end 25 on the inner side K2 and a second portion 24Ac extending from step 24Aa to the outer side K3 to the outer end face 26 differ by the length Ls of step 24Aa in the radial direction of wheel member 20.

[0050] The first portion 24Ab and the second portion 24Ac of the contact portion 24A each extend flatly in the wheel axis direction K1 without bending along the way in the wheel axis direction K1. Therefore, in the first portion 24Ab, the radial position of the contact portion 24A remains constant even when moving in the wheel axis direction K1, and the same is true in the second portion 24Ac.

[0051] The base end 31a (31Ma) of the bracket 30 (bracket 30M in the modified example) is formed in a stepped shape to correspond to such contact portion 24A, and when inserted into the groove 23A, it engages with the contact portion 24A so as to mesh with it, and is held in a state in which it is difficult to come off at least on one side of the wheel axis direction K1, i.e., the inner side K2.

[0052] In this way, the contact portion 24 (24A) that comes into contact with the base end portion 31a (31Ma) of the bracket 30 (30M) attached to the wheel member 20 (20A) is formed so that the radial position of the wheel member 20 is different in at least two parts that are positioned differently in the wheel axis center direction K1, and thereby can engage with the base end portion 31a (31Ma) of the bracket 30 (30M) so as not to cause relative misalignment between the bracket 30 (30M) and the wheel member 20 in the wheel axis center direction K1.

[0053] The curved plate portion 22A forming the outer circumferential portion 21A of the wheel member 20A according to the modified example of Fig. 8 is bent in the wheel axis direction K1, similar to the curved plate portion 22 of the wheel member 20 shown in Fig. 7 etc. The contact portion 24 in Fig. 7 is bent along the curved plate portion 22 in the wheel axis direction K1, so that the bottom end surface of the groove 23 has a constant depth in the radial direction of the wheel member 20. On the other hand, the contact portion 24A in Fig. 8 is flat in the first portion 24Ab and the second portion 24Ac, regardless of the bending of the curved plate portion 22A in the wheel axis direction K1, so that the depth of the groove 23A, which is a modified example of the groove 23 in the radial direction of the wheel member 20, changes as one moves in the wheel axis direction K1.

[0054] As described above, the contact portion 24 on the outer periphery 21 of the wheel member 20 is formed in a shape that takes into consideration contact (engagement) with the base end of the bracket 30, while the curved plate portion 22 on the outer periphery 21 of the wheel member 20 is formed in a shape that takes into consideration the situation around the omnidirectional wheel 50 when attached to the work vehicle 100.

[0055] Here, with reference to FIG. 12 , a state in which the omnidirectional wheels 50 are attached to a work vehicle 100 will be described. A work vehicle 100, such as an agricultural tractor, has a differential case 150, which houses a differential gear mechanism 154, pivotally supported on a vehicle body 101 by a center pin 151 in the front-to-rear direction. A pair of left and right differential yoke shaft cases 152a extend laterally from both the left and right sides of the differential case 150. Furthermore, a pair of left and right steering shaft cases 152b extend downward and outward from the left and right outer ends of the pair of left and right differential yoke shaft cases 152a. The pair of left and right differential yoke shaft cases 152a and the pair of left and right steering shaft cases 152b form an axle case (front axle case) 152. Note that FIG. 12 illustrates only the left axle case 152 of the pair of left and right axle cases 152 of the work vehicle 100.

[0056] The pair of left and right differential yoke shaft cases 152a respectively accommodate a pair of left and right differential yoke shafts 155 extending from the differential gear mechanism 154. The pair of left and right steering shaft cases 152b each accommodate a transmission mechanism 156 such as a reduction gear mechanism that interlocks and links the differential yoke shafts 155 and axles (hubs) 157, and the pair of left and right axles 157 protrude outwardly to the left and right from the pair of left and right steering shaft cases 152b.

[0057] The steering shaft case 152b functions as a steering shaft (kingpin) that can rotate around the steering axis Xs shown in Figure 12. Rotation of each steering shaft case 152b about the steering shaft allows the axle 157 to swing back and forth. Knuckle arms and the like extend from each steering shaft case 152b, and the knuckle arms of the pair of left and right steering shaft cases 152b are connected to each other via steering cylinders, tie rods, and the like.

[0058] In this way, the steering device 120 (see FIG. 36) of the work vehicle 100 is configured, which is made up of the pair of left and right steering shaft cases 152b, the knuckle arm, the steering cylinder, the tie rod, etc.

[0059] The steering device 120 will be described in detail later with reference to FIG.

[0060] The axle 157 serves as the wheel rotation axis (hub) of the omni-directional wheel 50 , and is inserted into the inner bore 28 of the wheel member 20 as described above, with its tip fixed to the flange portion 27 .

[0061] Assuming that the differential yoke shaft 155 is positioned horizontally, the axle 157 is tilted downward and outward on the left and right sides so that the tip end fixed to the flange portion 27 is lower than the base end connected to the transmission mechanism 156, so as to have a slight depression angle θ1. This depression angle θ1 is the camber angle (positive camber angle) θ1 of the omnidirectional wheels 50 of the work vehicle 100.

[0062] Similarly, assuming that the differential yoke shaft 155 is disposed horizontally, the steering axis Xs is inclined downward and outward on the left and right sides at a steering axis angle θ2 with respect to the vertical line VL.

[0063] Here, the tread of the omnidirectional wheel 50 is the apex (apex end surface 45a) of the lugs (protruding portions) 45 that protrude from the outer periphery of the plurality of rollers 40 arranged in the wheel rotation direction along the outer periphery 21 of the wheel member 20. Furthermore, of the plurality of lugs 45 of a ground-contact roller 40G, which is the roller 40 that has reached the lowest rotational position among the plurality of rollers 40 that rotate with the wheel member 20 in the wheel rotation direction, the apex (apex end surface 45a) of the lug 45 that has reached the lowest rotational position in the roller rotation direction (described below) is the ground-contact portion that actually comes into contact with the ground. The point at which the apex of the lug 45 of the lowest roller 40 comes into contact with the ground as the ground contact portion is referred to as the ground contact point Pg (see FIG. 9 ).

[0064] When the omnidirectional wheels 50 are steered using the steering device 120 of the work vehicle 100 configured as described above, the ground contact point Pg of the omnidirectional wheels 50 rotates as the steering shaft case 152b rotates about the steering axis Xs as the center of rotation. Now, consider the relationship between the ground contact point Pg of the omnidirectional wheels 50 and point Ps, where the steering axis Xs extends downward and intersects with the ground. If the ground contact point Pg is offset from point Ps in the wheel axis direction K1 of the omnidirectional wheels 50, this offset will cause the omnidirectional wheels 50 (rollers 40) to drag during steering.

[0065] Therefore, in order to reduce such drag and achieve smooth steering of the omnidirectional wheel 50, it is necessary to position the omnidirectional wheel 50 and support it on the work vehicle 100 so that the contact point Pg does not deviate from point Ps in the wheel axis direction K1, i.e., so that it coincides with point Ps.

[0066] The roller 40 has a maximum diameter at the protruding portion of the lug 45. In other words, the maximum diameter of the roller 40 is determined by factors such as the amount of protrusion of the lug 45. The position of the ground contact point Pg in the wheel axis direction K1 is determined by factors such as the relationship between the amount of protrusion of the lug 45 of the roller 40, the camber angle θ1 of the omnidirectional wheel 50, which corresponds to the depression angle θ1 of the axis of the axle 157 (wheel member 20), and the position of the flange portion 27 of the wheel member 20 (the portion where the tip of the axle 157 is attached) in the wheel axis direction K1.

[0067] In other words, the omnidirectional wheel 50 and the axle case 152 are designed so that the various settings described above are values ​​that allow the ground contact point Pg and point Ps to coincide with each other. According to this design, the inner bore 28 of the wheel member 20 of the omnidirectional wheel 50 is required to have a relatively large space so as to accommodate most of the steering shaft case 152b, as shown in FIG.

[0068] The axle 157 and wheel member 20 are positioned so that the wheel axis Xw is inclined downward toward the outer side K3 to ensure the camber angle θ1 of the omnidirectional wheel 50. Meanwhile, in the omnidirectional wheel 50 with the flange portion 27 of the wheel member 20 attached to the axle 157, the lugs 45 of the rollers 40 are close to the steering shaft case 152b. As described above, the wheel member 20, which is inclined downward and outward on the left and right, covers approximately the upper half of the rollers 40 located below it, both in the vicinity of the inner end face 25 and in the vicinity of the outer end face 26. Therefore, the diameter Dw1 of the outer peripheral edge of the inner end face 25 is made larger than the diameter Dw2 of the outer peripheral edge of the outer end face 26, so that the lower ends of the inner end face 25 and the outer end face 26 are at approximately the same height.

[0069] That is, the diameter ratio between the outer end (the outer peripheral edge of the outer end face 26) and the inner end (the outer peripheral edge of the inner end face 25) of the wheel member 20 is set to correspond to the camber angle θ1 of the omnidirectional wheel 50, which corresponds to the depression angle θ1 of the wheel axle center Xw of the wheel member 20.

[0070] Furthermore, the outer periphery 21 of the wheel member 20 is formed to bend along the roller rotation direction of the roller 40 so as to cover a plurality of lugs 45 that protrude radially from the outer periphery of the roller 40 arranged below it. In other words, the curved plate portion 22 of the outer periphery 21 of the wheel member 20 is bent in an arc shape so that the diameter changes as it moves in the wheel axis direction K1, and the contact portion 24, which is the radial bottom end surface of the groove 23, is bent along the curved plate portion 22.

[0071] The diameter of the curved plate portion 22 increases in the wheel axial direction K1 (inner side K2) from the outer end (the outer peripheral edge of the outer end surface 26) to the inner end (the outer peripheral edge of the inner end surface 25) which has a larger diameter than the outer end (the outer peripheral edge of the outer end surface 26). The corresponding shape of the curved plate portion 22 is like a wide-mouthed bottle that widens toward the inner end (the outer peripheral edge of the inner end surface 25), which is the open end.

[0072] Due to the configuration of the outer peripheral portion 21 of the wheel member 20 having the curved plate portion 22 that bends as described above, at least the portion of the curved plate portion 22 of the wheel member 20 including the inner end (the outer peripheral edge of the inner end surface 25) is positioned in the narrow gap between the lug 45 and the steering shaft case 152b that houses the axle 157, regardless of the rotation of the roller 40 in the roller rotation direction.

[0073] In other words, the curvature of the curved plate portion 22 (and the contact portion 24) of the outer periphery 21 of the wheel member 20 is set so that the curved plate portion 22 (and the contact portion 24 that bends along the curved plate portion 22) can be positioned in such a gap.

[0074] It should be noted that the diameter of the inner end (the outer peripheral edge of the inner end surface 25) of the wheel member 20 is not necessarily larger than the diameter of the outer end (the outer peripheral edge of the outer end surface 26). For example, in cases where application to a vehicle in which the axles are tilted outward and upward on the left and right sides to impart a negative camber angle to the omnidirectional wheels 50 is envisaged, the wheel member 20 may be configured such that the diameter of the outer end (the outer peripheral edge of the outer end surface 26) is larger than the diameter of the inner end (the outer peripheral edge of the inner end surface 25).

[0075] In other words, whether the omnidirectional wheel 50 supported by the work vehicle 100 has a positive camber angle or a negative camber angle, the wheel member 20 only needs to have the curved plate portion 22 with different diameters at the inner end (the outer peripheral edge of the inner end face 25) and the outer end (the outer peripheral edge of the outer end face 26) taking the camber angle into consideration, and the diameter ratio between the outer end (the outer peripheral edge of the outer end face 26) and the inner end (the outer peripheral edge of the inner end face 25) of the wheel member 20 is set corresponding to the camber angle of the omnidirectional wheel 50 corresponding to the angle of the wheel axle center Xw of the wheel member 20.

[0076] Next, the specific structure of the bracket 30 will be described in detail with reference to Figures 1 to 16. The bracket 30 is a bent plate-like member, as shown in Figures 13 and 14, etc. The bracket 30 has at least enough strength to rotatably support the roller 40 when attached to the outer periphery 21 of the wheel member 20. Such a bracket 30 is made by molding a synthetic resin plastic material, but it can also be made by bending, cutting, drilling, etc. a metal plate material, and there are no limitations on the material or structure.

[0077] 7, the bracket 30 has a flat support plate portion 31 having a width corresponding to the length Lw of the wheel axis Xw between the inner end surface 25 and the outer end surface 26 of the wheel member 20. One end of the support plate portion 31 is a base end portion 31a that is inserted into the groove 23 of the wheel member 20. The base end portion 31a is bent to correspond to the contact portion 24 of the wheel member 20 that bends in the wheel axis direction K1.

[0078] Furthermore, the contact portion 24 of the wheel member 20 may be configured so that at least one part and another part of the contact portion 24 that are positioned differently in the axial direction have different radial positions on the wheel member 20, and correspondingly, the base end portion 31a of the bracket 30 may also be configured to have at least one part and another part that are positioned differently in the radial direction on the wheel member 20 when attached to the outer periphery 21 of the wheel member 20, so as to correspond to the one part and the other part of the contact portion 24, respectively.

[0079] For example, as shown in Figure 8, the contact portion 24A of the aforementioned wheel member 20A, which is a modified example of the wheel member 20, has a first portion 24Ab and a second portion 24Ac separated by a step, and correspondingly, the base end portion 31Ma of the bracket 30M, which is a modified example of the bracket 30, is also formed in a shape having a similar step, so that the base end portion 31Ma of the bracket 30M inserted into the groove 23A reliably contacts (abuts) with the contact portion 24A with almost no gap, engages with at least the inner side K2 in the wheel axis direction K1 without any positional deviation, and is also prevented from falling off the outer circumferential portion 21A of the wheel member 20A.

[0080] As shown in Figure 5, etc., a plurality of brackets 30 are attached to the outer periphery 21 of the wheel member 20 by fitting the base end 31a of each bracket 30 into each groove 23, and these multiple brackets 30 attached to the wheel member 20 are arranged in the wheel rotation direction along the outer periphery 21 of the wheel member 20 (along the wheel circumferential line Cw in Figure 1).

[0081] Here, as shown in Figure 5, when viewed along the wheel axle center Xw, the support plate portion 31 of each bracket 30 attached to the wheel member 20 extends radially of the wheel member 20, and the support plate portions 31 of the multiple brackets 30 attached to the wheel member 20 protrude radially from the outer periphery 21 of the wheel member 20.

[0082] 14 and other figures, the bracket 30 has a screw hole 31c in the wheel axis direction K1 that opens in an end face (outer end face 31b) facing the outside K3 of the support plate portion 31. As shown in Figures 7 and 14 and other figures, the outer end face 31b is flush with the outer end face 26 of the wheel member 20 when the base end portion 31a of the support plate portion 31 is fitted into the groove 23 and engaged (contacted) with the contact portion 24.

[0083] 7, 9, 11, etc., an annular stop plate 61 abuts against the outer end surface 26 of the wheel member 20 and the outer end surfaces 31b of the support plate portions 31 of the plurality of brackets 30 attached to the wheel member 20. As shown in Fig. 13, etc., the stop plate 61 is provided with boss holes (or screw holes) 61a corresponding to the screw holes 31c of the plurality of brackets 30, and boss holes (or screw holes) 61b corresponding to the screw holes 26a opening in the outer end surface 26 of the wheel member 20.

[0084] 9, 11, 13, etc., screws or bolts are threaded into these boss holes and / or screw holes 31c, 61a, 26a, 61b to fasten the retaining plate 61 to the wheel member 20 and the plurality of brackets 30 attached to the wheel member 20. This reliably fixes the plurality of brackets 30 to positions in the wheel axis direction Xw where the outer end surface 31b of the support plate portion 31 is flush with the outer end surface 26 of the wheel member 20, preventing wobble of the brackets 30 in the wheel axis direction K1.

[0085] Furthermore, as shown in Figures 7, 9, 11, etc., when the base end 31a of the support plate portion 31 of the bracket 30 is inserted into the groove 23 and engaged (contacted) with the contact portion 24, the inner end surface 31d facing the inward K2 of the support plate portion 31 is flush with the inner end surface 25 of the wheel member 20.

[0086] 7, 9, 11, 14, etc., a flat stay 31e extending in the wheel axis direction K1 is formed on the support plate portion 31 of the bracket 30, and a screw hole 31f extending in the radial direction of the wheel member 20 is formed in the stay 31e. Meanwhile, the curved plate portion 22 of the outer circumferential portion 21 of the wheel member 20 is chamfered along the outer circumferential edge of the inner end face 25 between adjacent grooves 23 to form flat surfaces 22a, and a screw hole 22b extending in the radial direction of the wheel member 20 opens in each flat surface 22a.

[0087] As shown in Figure 14, when the base end 31a of the support plate portion 31 of the bracket 30 is inserted into the groove 23 and engaged with the contact portion 24, the stay 31e abuts against the flat surface 22a of the wheel member 20, and the screw hole 31f of the stay 31e and the screw hole 22b of the wheel member 20 are connected on the same axis.

[0088] The stays 31e of the brackets 30 are fastened to the wheel member 20 by screws or bolts threaded into the screw holes 31f, 22b. This reliably fixes the brackets 30 in positions in the wheel axis direction K1 where the inner end surfaces 31d of the support plate portions 31 are flush with the inner end surfaces 25 of the wheel members 20, further reliably preventing the brackets 30 from wobbling in the wheel axis direction K1.

[0089] 6, 14, etc., an L-shaped bent portion 32 is formed on the other end of the support plate portion 31 of each bracket 30, on the side opposite the base end portion 31a in the radial direction of the wheel member 20. When the base end portion 31a is fitted into the groove 23 and engaged with the contact portion 24, i.e., when the bracket 30 is attached to the outer periphery 21 of the wheel member 20, the L-shaped bent portion 32 has an L-shaped recessed portion 32a on one side in the wheel rotation direction along the wheel circumferential line Cw, and an L-shaped protruding portion 32b on the other side.

[0090] 6 and 13, each bracket 30 (representative bracket 30X representing the plurality of brackets 30) attached to the outer periphery 21 of the wheel member 20 supports at least two rollers 40 out of the plurality of rollers 40 arranged in the wheel rotation direction along the outer periphery 21. As shown in Fig. 6 and 13, the at least two rollers 40 supported by each bracket 30 (representative bracket 30X) include a first roller 40A arranged on one side of the bracket 30 in the wheel rotation direction, and a second roller 40B arranged on the other side of the bracket 30.

[0091] 6, 13, 14, etc., each roller 40 has a first end 40a on one side in the wheel rotation direction, a second end 40b on the other side, and a bracket insertion recess 40c that opens at the first end 40a. The second end 40b of the first roller 40A is inserted into the roller insertion recess 32a of the bracket 30 (representative bracket 30X), and the protrusion 32b of the bracket 30 (representative bracket 30X) is inserted into the bracket insertion recess 40c of the second roller 40B (see FIGS. 6, 14, etc.).

[0092] As can be seen in Figures 5, 6, etc., each roller 40 has a roller shaft 41 that serves as the center axis of rotation of the roller 40, and a first end 41a of the roller shaft 41 protrudes into the bracket insertion recess 40c at the first end 40a of the roller 40, and a second end 41b of the roller shaft 41 protrudes beyond the second end 40b of the roller 40.

[0093] 6 and other figures, each roller 40 has an axial hole 40d that defines the roller axial line Xr. The axial hole 40d is a through hole that opens on both the first end 40a (bracket insertion recess 40c) side and the second end 40b side.

[0094] The roller shaft 41 is longer than the shaft hole 40d in the roller shaft direction Xr. The roller shaft 41 is inserted through the shaft hole 40d, with the first end 41a protruding from the opening end of the shaft hole 40d on the first end 40a side and the second end 41b protruding from the opening end of the shaft hole 40d on the second end 40b side.

[0095] 6, flanged bushings 46 are provided at the opening end of the shaft hole 40d in the main body 42 (core post member 43) on the first end 40a side and the opening end on the second end 40b side. The bushings 46 are bearing members interposed between the outer peripheral surface of the roller shaft 41 and the inner peripheral surface of the main body 42 (core post member 43).

[0096] As shown in Figures 5, 6, 13, 14, etc., the L-shaped bent portion 32 of the bracket 30 has a first shaft support recess 32c that opens to one side in the wheel rotation direction at the roller insertion recess 32a, and a second shaft support recess 32d that opens to the other side in the wheel rotation direction at the protrusion 32b. 6 and 13, the second end 41b of the roller shaft 41 of the first roller 40A protrudes from the first roller 40A via a bushing 46 at the open end of the shaft hole 40d on the second end 40b side and is inserted into the first shaft support recess 32c in the bent portion 32 of the bracket 30 (representative bracket 30X), and the first end 41a of the roller shaft 41 of the second roller 40B protrudes from the second roller 40B via a bushing 46 at the open end of the shaft hole 40d on the first end 40a side and is inserted into the second shaft support recess 32d in the bent portion 32 of the bracket 30 (representative bracket 30X).

[0097] Conversely, as can be seen in Figure 6, etc., when viewed from each roller 40, the first end 41a of the roller shaft 41 is inserted into the second shaft support recess 32d of the bracket 30 on one side of the roller 40 in the wheel rotation direction, and the second end 41b of the roller shaft 41 is inserted into the first shaft support recess 32c of the bracket 30 on the other side of the roller 40 in the wheel rotation direction, so that the roller shaft 41 is supported at both ends of the roller 40 by two separate brackets 30.

[0098] As shown in Figure 6, in each bracket 30, the first shaft support recess 32c and the second shaft support recess 32d form an angle corresponding to the roller angle θr formed by the roller axes 41 (roller axis core lines Xr) of the first roller 40A and the second roller 40B.

[0099] In each bracket 30, the first shaft support recess 32c, which opens at the recess 32a on one side in the wheel rotation direction, also opens at the protrusion 32b on the other side in the wheel rotation direction, i.e., forms a through hole. As shown in Figure 13, etc., a stop plate 33 can be attached to the protrusion 32b so as to cover the opening end on the other side of the first shaft support recess 32c. In other words, when the second end 41b of the roller shaft 41 is inserted into the first shaft support recess 32c from the one side, the stop plate 33 can be attached to the protrusion 32b of the bracket 30 to prevent the second end 41b of the roller shaft 41 from coming out.

[0100] Next, a detailed description will be given of the specific structure of the roller 40. The roller 40 has the roller shaft 41 as described above, and the central axis of the roller shaft 41 is the roller axis line Xr of the roller 40.

[0101] As shown in Figures 5, 6, 7, 9, 11, 13, 14, etc., each roller 40 has a main body 42 mounted around the roller shaft 41. Specifically, the main body 42 is made up of a core post material 43 and an exterior material 44 mounted around the core post material 43. The core post material 43 is provided with a core hole 40d that defines the roller axial center line Xr.

[0102] The core pillar material 43 may be made of, but is not limited to, metal or synthetic resin so as to ensure the strength required for the rollers 40 of the omnidirectional wheel 50. The exterior material 44 forms the ground contact portion of the rollers 40 (strictly speaking, it forms the lugs 45 described below having top end surfaces 45a that form the ground contact portions of the rollers 40), so it may be made of, but is not limited to, a rubber member (natural or synthetic) suitable for ground contact.

[0103] The outer periphery of roller 40 is the outer periphery of main body 42, and is composed of exterior material 44 wrapped around core post material 43. In this way, lugs 45 are formed on the outer periphery of main body 42 made of exterior material 44. Lugs 45 are protruding parts that protrude from the outer periphery of roller 40 (main body 42) so as to resist rotation of roller 40 in the roller rotation direction.

[0104] In other words, when a force or load is applied to the omnidirectional wheels 50 supported on the work vehicle 100 in a direction different from the wheel rotation direction corresponding to the direction of travel, the rollers 40 rotate in the roller rotation direction without skidding, reducing friction with the ground. However, if there is no resistance at all in the roller rotation direction and the rollers 40 are able to rotate freely in that direction, when the rollers 40 become embedded in soft ground or the like, their traction force is weak, causing them to spin freely and become stuck. Therefore, in order to impart such traction force to the rollers 40, the omnidirectional wheels 50 have lugs (protrusions) 45 that protrude from the outer periphery of the rollers 40 (the outer surface of the exterior material 44), as described above.

[0105] 1 and other figures, the roller 40 has a plurality of lugs (protrusions) 45. The lugs (protrusions) 45 protrude radially from the outer periphery of the roller 40 (the outer periphery surface of the main body 42 (exterior material 44) excluding the lugs 45) around the roller axis Xr and are arranged in the roller rotation direction. As the omnidirectional wheel 50 rotates in the wheel rotation direction, the roller 40 that reaches the lowest position among the plurality of rollers 40 becomes the ground roller 40G that comes into contact with the ground.

[0106] The roller 40 (main body 42) has a shape in which the diameter changes as it moves in the direction along the roller axial line Xr (hereinafter referred to as the "roller axial direction"). Note that, as shown in Figures 7, 9, 11, etc., the diameter of the roller 40 refers to the diameter of the outer circumferential surface of the exterior material 44 of the main body 42, excluding the lugs (protrusions) 45, centered on the roller axial line Xr (roller shaft 41). Hereinafter, this will be referred to as the roller diameter Dr.

[0107] The shape of the roller 40 in which the diameter changes as it moves in the roller axial direction means that (the main body 42 of) the roller 40 is formed so that the radial expansion of the roller 40 changes as it moves in the roller axial direction. In other words, the roller 40 is not a columnar (cylindrical) shape with a constant diameter over the entire length from one end to the other in the roller axial direction, but has a structure in which at least two portions located at different positions in the roller axial direction have different diameters.

[0108] Specific examples of roller shapes in which at least two portions at different positions in the roller axial direction have different diameters include a shape formed by connecting two or more cylindrical (cylinder)-shaped portions of different diameters coaxially. For example, a roller formed by connecting a small-diameter cylindrical (cylinder) portion and a large-diameter cylindrical (cylinder) portion of a larger diameter coaxially (where the large-diameter portion and the small-diameter portion are joined, there is a step in the radial direction), or a roller formed by connecting three or more cylindrical (cylinder)-shaped portions of different diameters, such as small, medium, and large diameters, together in the roller axial direction (where the joints between the cylindrical (cylinder)-shaped portions of different diameters form a step).

[0109] Alternatively, the roller may have a shape with a smooth curved outer circumferential surface without any steps as described above. The roller 40 according to the present embodiment is also an example of a roller having such a curved shape. Examples of the overall shape of such a roller include a truncated cone shape in which the diameter gradually increases (or decreases) from one end of the roller in the axial direction to the other end, a cup (teacup, bowl, or basin) shape in which the diameter is substantially constant or decreases at a small rate from one end of the roller in the axial direction to the vicinity of the other end (the middle part in the axial direction) and then decreases at a large rate from the vicinity of the other end (the middle part in the axial direction) to the other end, a barrel shape or a rugby ball shape in which the central part in the roller axial direction is the largest diameter and is the most bulging in the radial direction, and a drum shape or anvil shape in which the central part in the roller axial direction is the smallest diameter and is narrowed.

[0110] 1 to 16, the roller 40 (main body 42) according to this embodiment can be said to have a bowl (cone) shape in which the roller diameter Dr gradually decreases from one end (first end 40a) to the other end (second end 40b) in the roller axial direction. The shape of the roller 40 will be described in more detail later.

[0111] The lugs (protrusions) 45 protrude from at least the portion of the outer periphery of the roller 40 (the outer periphery surface of the main body 42 (excluding the lugs 45)) where the roller diameter Dr is greatest. Therefore, a large distance is ensured between the top ends of the lugs 45 and the roller axis line Xr, and even if the roller 40 becomes the lowest ground-contacting roller 40G and sinks into soft ground, the upper part of the ground-contacting roller 40G is exposed above the soft ground, increasing the possibility of the roller 40 exerting its traction force.

[0112] The configuration in which the diameter Dr changes will now be described in detail. As described above, the roller 40 has a first end 40a and a second end 40b that face each other in the roller axial direction. As can be seen by comparing the shape of the roller 40 shown in Figures 1 to 6 and the roller diameter Dr shown in Figures 7, 9, and 11, the roller diameter Dr at the first end 40a is larger than the roller diameter Dr at the second end 40b, and the lug (protruding portion) 45 protrudes from the outer periphery of at least the first end 40a (the outer periphery surface of the main body 42 (excluding the lug 45)) of the first end 40a and the second end 40b.

[0113] More specifically, the roller 40 has a shape in which the roller diameter Dr gradually decreases as it moves from the first end 40a to the second end 40b in the axial direction (along the roller axis line Xr), i.e., a cup shape that tapers toward the second end 40b. The multiple lugs 45 are formed on the exterior material 44 of the main body 42 so as to be arranged along the outer periphery (roller circumferential line Cr) of the roller 40 at the first end 40a, which has the largest roller diameter Dr (hereinafter referred to as the "maximum roller diameter Drm" (see FIG. 14)) in the roller axial direction.

[0114] In addition, the roller 40 in this embodiment only has a plurality of lugs 45 arranged in a row at the first end 40a (this row of the plurality of lugs 45 is referred to as the "lug row 45L" (see Figure 2, etc.)), but in addition to this, a plurality of lugs (protrusions) arranged along the outer periphery of the roller 40 may also be provided, for example, in the middle of the roller axial direction.

[0115] Furthermore, the shape of the roller 40 may be, for example, a barrel shape with the maximum diameter Dr at the intermediate portion between the first end 40a and the second end 40b, and in this case, a plurality of lugs (protrusions) may be provided at least at the intermediate portion, arranged along the outer periphery of the roller 40.

[0116] 4 and other figures, the lugs 45 of each roller 40 have the same shape and the same dimensions. Each lug 45 has a three-dimensional shape that is approximately a truncated quadrangular pyramid (ingot), and its apex (the portion farthest from the roller axis Xr in the radial direction of the roller 40 (hereinafter referred to as the "roller radial direction")) forms an apex surface 45a that is a rectangular flat surface when viewed in the roller radial direction.

[0117] Of the four sides of the approximately rectangular shape defined by the top end surface 45a, two sides extend along the roller axial direction and face each other in the roller rotation direction, and the remaining two sides extend in the roller rotation direction and face each other in the roller axial direction.

[0118] In this embodiment, the two sides of the substantially rectangular top end surface 45a along the roller axial direction are long sides, and the two sides along the roller rotation direction are short sides, but this is not limited to this, and the long and short sides may be reversed. Alternatively, the top end surface 45a may be square when viewed in the roller radial direction. Furthermore, the shape of the top end surface 45a of the lug (protrusion) 45 as viewed in the roller radial direction may vary, and is not limited to the rectangular shape described in the embodiment or above.

[0119] Furthermore, the top end surface 45a does not have to be a flat surface, and may be, for example, one whose rising height (the radial protrusion of the roller 40) from the outer peripheral surface of the roller 40 (excluding the lug 45) changes as it moves in the direction of the roller axis or the direction of roller rotation.

[0120] The lug 45 has a pair of side surfaces 45b and a pair of side surfaces 45c that extend in the roller radial direction from the outer peripheral surface (other than the lug 45) of the main body 42 (exterior material 44) to the top end surface 45a.

[0121] In this embodiment, the overall three-dimensional shape of the lug 45 is a substantially quadrangular pyramid (ingot) shape as described above, and therefore the shape of each of the side surfaces 45b, 45c is a trapezoid that tapers toward the top surface 54a, but this shape is not limited to this. For example, the overall three-dimensional shape of the lug 45 may be a rectangular parallelepiped or cube, and the shape of each of the side surfaces 45b, 45c may be a rectangle or a square.

[0122] The pair of side surfaces 45b extend along the roller axial direction and face each other in the roller rotation direction (direction along the roller circumferential line Cr) (hereinafter, the side surfaces 45b are referred to as "axial side surfaces 45b"). The pair of side surfaces 45c extend along the roller rotation direction (the outer periphery of the roller 40) and face each other in the roller axial direction (hereinafter, the side surfaces 45c are referred to as "outer periphery side surfaces 45c").

[0123] The lugs 45 are arranged along the outer periphery of the roller 40 (main body 42) in the direction of roller rotation, so that the axial side surface 45b of each lug 45 faces, in the direction of roller rotation, the axial side surface 45b of another lug 45 adjacent to that lug 45. The gap G (see FIG. 9, etc.) between the adjacent lugs 45 on the outer periphery of the roller 40 is between the axial side surfaces 45b facing each other in this way.

[0124] 4, one of the pair of outer peripheral side surfaces 45c (referred to as "one-side side surface 45c1") faces one side in the wheel rotation direction, and the other (referred to as "other-side side surface 45c2") faces the other side in the wheel rotation direction. Each of the multiple lugs 45 moves toward or away from the outer peripheral portion 21 of the wheel member 20 as the roller 40 rotates.

[0125] When the lug 45 enters the gap between the support plate portions 31 of adjacent brackets 30 and reaches a position close to the outer periphery 21 of the wheel member 20 (the lug 45 that reaches this position is referred to as "lug 45X"), one side surface 45c1 comes close to and faces the support plate portion 31 of the bracket 30 on one side of the roller 40 in the wheel rotation direction (referred to as "first bracket 30A"), and the other side surface 45c2 comes close to and faces the support plate portion 31 of the bracket 30 on the other side of the roller 40 in the wheel rotation direction (referred to as "second bracket 30B").

[0126] 4, the top end surface 45a of the lug 45X is closest to the outer periphery 21 of the wheel member 20. In the above-described ground-contact roller 40G, the lug 45X is located at the highest position among the multiple lugs 45. The higher the top end surface 45a of the lug 45X is, the less likely the roller 40, including the multiple lugs 45, will become completely buried in soft ground or mud (get stuck), and the more likely it is that the roller 40's crossing ability will be increased (crossing performance will be improved).

[0127] Therefore, among the various parts of the main body 42 that are positioned differently in the direction of the roller axis, the roller 40 forms multiple lugs 45, i.e., lug row 45L, in the part corresponding to the first end 40a having the maximum roller diameter Drm, as described above.

[0128] As a result, when the roller 40 becomes a ground contact roller 40G, the top end surface 45a of the lug 45X becomes so high that it approaches the outer periphery 21 of the wheel member 20, and the roller 40 that has become a ground contact roller 40G can exert the traction force required of an omnidirectional wheel 50.

[0129] Furthermore, if the purpose is to raise the top end surface 45a (ground contact portion) of the ground contact roller 40G so that it does not sink into soft ground, etc., the lugs (protrusions) do not need to be multiple lugs 45 (i.e., lug row 45L) spaced at intervals corresponding to the gap G as described above; for example, they may be a single continuous lug (protrusion) with no gaps in between that runs around the entire outer periphery of the roller 40, like the lug 7a of the second roller 7 of the omnidirectional wheel 1 described below (see Figures 17 to 20, etc.).

[0130] However, the rollers 40 of the omnidirectional wheel 50 according to this embodiment are required to have an adequate grip on the ground by receiving an appropriate resistance to rotation in the roller rotation direction (second rotation direction) so as to prevent the rollers from getting stuck and spinning freely in the roller rotation direction (second rotation direction) on soft ground, while still being able to rotate freely in the roller rotation direction (second rotation direction) that intersects the wheel rotation direction (first rotation direction). Furthermore, the rollers 40 are required to have an adequate grip on the ground with a simple structure that ensures such grip, and are provided with lugs (protrusions) 45 that are configured to meet these requirements.

[0131] That is, the lugs (protrusions) 45 of the rollers 40 of the omnidirectional wheel 50 according to this embodiment protrude from the outer periphery of the rollers 40 (the outer periphery of the main body 42 (exterior material 44) excluding the lugs 45) so as to resist rotation of the rollers 40 in the roller rotation direction (second rotation direction). The resistance of the rollers 40 from the lugs 45 reduces the frequency of the rollers 40 spinning freely in the roller rotation direction (stuck state) on soft ground, for example.

[0132] In particular, the lug (protrusion) 45 of the roller 40 in the omnidirectional wheel 50 according to this embodiment has an axial side surface 45b extending in the direction of the roller axis, which intersects (is perpendicular to) the direction of roller rotation, as a portion that generates resistance to the rotation of the roller 40 in the direction of roller rotation.

[0133] In detail, each axial side surface 45b of each lug 45 is a surface facing the roller rotation direction (second rotation direction), and faces the gap G between adjacent lugs 45 in the roller rotation direction (second rotation direction).

[0134] Therefore, in an omnidirectional wheel 50 of a vehicle traveling on soft ground or the like, the axial side 45b (of the pair of axial side surfaces 45b, the axial side surface 45b that is the rearmost in the actual rotation direction of the ground contact roller 40G) of the ground contact lug 45G (see FIG. 9) that is located at the lowest end of the ground contact roller 40G and is actually in contact with the ground) encounters resistance from the soil that has entered the gap G immediately behind it as it moves rearward as the ground contact roller 40G rotates. As a result, resistance is generated at the axial side surface 45b against the rotation of the ground contact roller 40G in the roller rotation direction, and this resistance allows the ground contact roller 40G to ensure an appropriate grip on the ground so that it can avoid becoming stuck, even while rotating in the roller rotation direction.

[0135] Furthermore, for example, when a vehicle equipped with omnidirectional wheels 50 travels in a field such as a rice paddy where water is present to a certain depth above the ground surface, muddy water rather than soil and sand will seep into the gaps G between the lugs 45, and the muddy water that has penetrated into the gaps G will act as agitation resistance to the roller 40 attempting to rotate in the roller rotation direction, resulting in the muddy water being applied to the axial side surface 45b. In other words, even when a vehicle equipped with omnidirectional wheels 50 travels in a rice paddy or the like, the ground-contact lug 45G will receive resistance to the rotation of the ground-contact roller 40G in the roller rotation direction that occurs on the axial side surface 45b, just as when traveling on soft ground, and the like, thereby ensuring grip on the ground.

[0136] In this way, the lug (protrusion) 45 of the roller 40 in this embodiment protrudes from the outer periphery of the roller 40 (the outer periphery of the main body 42 (outer material 44) excluding the lug 45) so as to have an axial side 45b (a surface facing the roller rotation direction (second rotation direction)) that extends in the roller axial direction intersecting (orthogonal to) the roller rotation direction.

[0137] However, this is one specific embodiment of the lugs (protrusions) configured to protrude from the outer periphery of the roller 40 (the outer periphery of the main body 42 (exterior material 44) excluding the lugs 45) so as to resist rotation of the roller 40 in the roller rotation direction (second rotation direction). In other words, other specific embodiments of the lugs (protrusions) that protrude so as to resist rotation of the roller in this way are conceivable.

[0138] It is also possible to provide a lug that extends continuously around the entire circumference of the roller 40, like the lug 7a of the second roller 7 of the omnidirectional wheel 1 described below. Such a lug has a side surface that extends in the roller rotation direction (second rotation direction) of the roller 40, i.e., a surface that faces the wheel rotation direction (first rotation direction), and this surface can be a portion that generates resistance to the rotation of the omnidirectional wheel 50 in the wheel rotation direction (first rotation direction).

[0139] Now, in the case of the lug 45 according to this embodiment, the part where resistance to the rotation of the roller 40 (ground contact roller 40G) in the roller rotation direction occurs is the axial side 45b, so if you want to increase this resistance and improve the grip of the roller 40 on the ground, you can consider increasing the area of ​​the axial side 45b where this resistance occurs.

[0140] One way to increase the area of ​​the axial side 45b is to increase the width of the lug 45 between one side 45c1 and the other side 45c2 in the roller axial direction (the longitudinal length of the top end surface 45a and the axial side 45b).

[0141] Therefore, when each lug 45 becomes lug 45X, the width in the roller axis direction, i.e., the length along the roller axis of the top end face 45a and the axial side face 45b between the one side face 45c1 and the other side face 45c2, is increased until the one side face 45c1 comes as close as possible to the support plate portion 31 of the first bracket 30A and the gap between the one side face 45c1 and the support plate portion 31 of the first bracket 30A becomes suitably small, and the other side face 45c2 comes as close as possible to the support plate portion 31 of the second bracket 30B and the gap between the other side face 45c2 and the support plate portion 31 of the second bracket 30B becomes suitably small.

[0142] In this way, when the lug (protrusion) 45 of the roller 40 in this embodiment becomes the lug 45X that is closest to the outer periphery 21 of the wheel member 20, it is sandwiched between the first bracket 30A and the second bracket 30B, and therefore there is a limit to how much it can expand in the direction of the roller axis. By expanding to or near that limit, an appropriate resistance is applied to the rotation of the roller 40 in the direction of roller rotation, ensuring an appropriate grip force for the roller 40.

[0143] In order to ensure that the roller 40 receives the resistance generated by the axial side surfaces 45b of the lugs 45 at any rotational position of the roller 40 in the roller rotation direction (second rotation direction), it is preferable that a suitable number of axial side surfaces 45b (i.e., gaps G between the lugs 45 facing the axial side surfaces 45b) are arranged in the roller rotation direction (second rotation direction). In other words, it is preferable that the lug row 45L is formed by a suitable number of lugs 45.

[0144] Therefore, the lug (protrusion) 45 of the roller 40 according to this embodiment has a generally rectangular top end surface 45a when viewed in the radial direction of the roller 40, with the axial side surface 45b (the surface facing the roller rotation direction (second rotation direction)) being located on the long side of the generally rectangular top end surface 45a, and the outer circumferential side surface 45c (the surface facing the wheel rotation direction (first rotation direction)) being located on the short side of the generally rectangular top end surface 45a. In other words, the longitudinal direction of the generally quadrangular truncated pyramidal lug 45 is oriented in the roller axial direction, and the lateral direction is oriented in the roller rotation direction (second rotation direction).

[0145] That is, in each lug 45, the axial side surface 45b, which is the part that generates resistance to the rotation of the roller 40 in the roller rotation direction (second rotation direction), is arranged on the long side of the approximately rectangular top end surface 45a, so that each axial side surface 45b can generate sufficient resistance to ensure the grip force of the roller 40.

[0146] On the other hand, in each lug 45, the outer peripheral side surface 45c along the roller rotation direction (second rotation direction), which corresponds to the arrangement direction of the multiple lugs 45 in the lug row 45L, is arranged on the short side of the approximately rectangular top end surface 45a, so that an appropriate number of lugs 45 are arranged in the lug row 45L, and the roller 40 can reliably withstand the resistance generated on the axial side surface 45b of the lug 45 against rotation in the roller rotation direction (second rotation direction) at any rotation position of the roller 40 in the roller rotation direction (second rotation direction).

[0147] The omnidirectional wheel 50 secures gripping force by receiving resistance generated by the outer peripheral side surface 45 c against rotation in the wheel rotation direction (first rotation direction). The outer peripheral side surface 45 c is not continuous around the entire circumference of the roller 40 in the wheel rotation direction (first rotation direction), but is composed of multiple outer peripheral side surfaces 45 c arranged intermittently. However, the number of lugs 45 in the lug row 45L, the spacing between the lugs 45 as gap G, the area of ​​each outer peripheral side surface 45 c, and the like are set to values ​​suitable for providing the omnidirectional wheel 50 with appropriate resistance against rotation in the wheel rotation direction (first rotation direction).

[0148] Each roller 40 has a lug row 45L formed along the outer periphery of the first end 40a. The lug row 45L has a constant width in the roller axial direction, determined by the longitudinal lengths of the top end surface 45a and the axial side surface 45b. As described above, the roller axis lines Xr of a pair of adjacent rollers 40 intersect at the roller angle θr (see FIGS. 2 and 6 ). Therefore, as can be seen in FIGS. 1 to 6 , the spacing between the lug rows 45L narrows toward the outer periphery 21 of the wheel member 20 (i.e., the gap between adjacent lugs 45X is narrow enough to accommodate the thickness of the support plate portion 31 of the bracket 30). The spacing widens toward the outer periphery of the omnidirectional wheel 50, away from the outer periphery 21 of the wheel member 20.

[0149] Therefore, at the outer circumferential end of the omnidirectional wheel 50, between the lug rows 45L, there is a wide space free of protrusions such as the lugs 45, extending along the outer circumferential surface of the roller 40 (main body 42) in the wheel rotation direction (first rotation direction). By providing such a space, just before each lug 45 approaches the lowest position of the ground-contacting roller 40G and becomes a ground-contacting lug 45G (i.e., a lug 45 with its top end surface 45a in contact with the ground), the corner of the lug 45 between the top end surface 45a and the outer circumferential side surface 45c reliably contacts (or digs into) the ground.

[0150] In this way, when the lug 45 becomes the ground contact lug 45G, it exerts good grip on the ground, so that the ground contact lug 45G is pressed firmly against the ground with which it is in contact, and this pressing force presses the ground contact lug 45G against the ground (in the direction of gravity), contacting the roller 40 (ground contact roller 40G) in the roller rotation direction (second rotation direction), and providing resistance when the ground contact roller 40G tries to rotate in the roller rotation direction (second rotation direction).

[0151] That is, within one lug row 45L, the lug (protrusion) 45 is spaced apart from adjacent lugs (protrusions) 45, thereby providing an axial side surface 45b (extending in the roller axial direction) facing the roller rotation direction (second rotation direction); in addition, at the outer peripheral end of the omnidirectional wheel 50, a space is provided between the lug row 45L to which the lug 45 belongs and the adjacent lug row 45L, thereby providing an outer peripheral side surface 45c (extending in the roller rotation direction (second rotation direction)) facing the wheel rotation direction (first rotation direction).

[0152] In this way, the axial side surface 45b and the circumferential side surface 45c of the lug (protrusion) 45 protruding from the outer periphery of the roller 40 are the parts that generate resistance to the rotation of the roller 40 in the roller rotation direction (second rotation direction).

[0153] As described above, the lugs (protrusions) 45 of the roller 40 in this embodiment protrude from the outer periphery of the roller 40 so as to provide resistance to the rotation of the roller 40 in the roller rotation direction (second rotation direction).

[0154] As mentioned above, there is a limit to how much the lugs 45, which are expected to enter the gaps between the support plate portions 31 of adjacent brackets 30 while the roller 40 is rotating, can expand in the axial direction of the roller 40. However, if it is desired to further increase the resistance of the lugs 45 to the rotation of the roller 40, it is also possible to increase the number of lug rows 45L and form multiple lug rows 45L on each roller 40 so that they are parallel to each other in the axial direction of the roller.

[0155] Here, as can be seen in Figure 4, if another lug row 45L is formed on the outer surface of the main body 42 (outer material 44) on the second end 40b side of the lug row 45L along the first end 40a, when the lugs 45 belonging to this other lug row 45L approach the outer periphery 21 of the wheel member 20 during rotation of the roller 40, they will enter the roller insertion recess 32a of the other bracket 30 (second bracket 30B) that is positioned in the bracket insertion recess 40c of another roller 40 adjacent to the other side of the roller 40.

[0156] Therefore, by modifying the shape of the main body 42 of the roller 40 or the shape of the bent portion 32 of the bracket 32 ​​so that the lugs 45 can pass through the roller insertion recess 32a in the bracket insertion recess 40c while the roller 40 is rotating, it is also possible to form multiple lug rows 45L on each roller 40 so that they are parallel to each other in the direction of the roller axis.

[0157] In the omnidirectional wheel 50 of this embodiment, one roller 40 is supported between every two adjacent brackets 30, and each roller 40 is provided with a single roller row 45L. The longitudinal direction of each lug 45, which is approximately a truncated quadrangular pyramid and belongs to this lug row 45L, is oriented in the direction of the roller axis and extended as far as possible in this longitudinal direction. This simple configuration realizes an omnidirectional wheel 50 equipped with rollers 40 that have an appropriate gripping force and receive appropriate resistance to the rotation of the rollers 40 in the roller rotation direction.

[0158] As described above, the roller 40 of the omnidirectional wheel 50 according to this embodiment has the width of the lugs 45 in the roller axial direction (the longitudinal length of the top end faces 45a and the axial side faces 45b) enlarged as much as possible, thereby providing a moderate resistance to rotation in the roller rotation direction due to the protrusion of the lugs (protrusions) 45, thereby ensuring grip on the ground. Furthermore, by forming the lugs 45 (lug row 45L) in the part of the main body 42 of the roller 40 that corresponds to the first end 40a having the maximum roller diameter Drm, the position of the top end face 45a of the lug 45X located at the top of the ground-contact roller 40G is raised, thereby ensuring traction on soft ground, etc.

[0159] In addition, it is also possible to increase the amount of protrusion of the lug 45 to the top end surface 45a in the radial direction of the roller 40 in order to increase the resistance to rotation of the roller 40 in the roller rotation direction, thereby improving the grip of the roller 40, and further to raise the position of the top end surface 45a of the lug 45X, which is the topmost part of the ground-contacting roller 40G, thereby improving the walking ability of the roller 40.

[0160] The above-described configuration of the lug 45 can be summarized as follows.

[0161] In other words, when the multiple brackets 30 attached to the outer periphery 21 of the wheel member 20 include a first bracket 30A that supports the roller 40 on one side in the wheel rotation direction and a second bracket 30B that supports the roller 40 on the other side, the lug (protrusion) 45 of the roller 40 has a one-side side surface (first side surface) 45c1 facing the one side, an other-side side surface (second side surface) 45c2 facing the other side, and a top end surface 45a extending between the one-side side surface (first side surface) 45c1 and the other-side side surface (second side surface) 45c2 at the radial apex from the roller axis line Xr, which is the axis of the roller 40. As the roller 40 rotates in the roller rotation direction, the lug (protrusion) 45 reaches a position where the top end surface 45a faces the wheel member 20 in the gap between the first bracket 30A and the second bracket 30B (i.e., becomes "lug 45X"), and one side surface (first side surface) 45c1 faces the first bracket 30A (support plate portion 31), and the other side surface (second side surface) 45c2 faces the second bracket 30B (support plate portion 31).

[0162] Thus, in the lug 45X, the gap between the top end surface 45a and the wheel member 20, the gap between one side surface 45c1 and the support plate portion 31 of the first bracket 30A, and the gap between the other side surface 45c2 and the support plate portion 31 of the second bracket 30B are all narrow, so that when the lug 45X is buried in soft ground or the like, a large surface area is ensured for the axial side surface 45b to come into contact with the soil, allowing a large surface pressure to be applied to the soil. This surface pressure acts as resistance to the rotation of the roller 40 (ground contact roller 40G) in the roller rotation direction, imparting a breaking force to the ground contact roller 40G against the soil and encouraging the ground contact roller 40G to escape from a stuck state.

[0163] Next, in relation to the lug 45 configured as described above, the stopper 60 attached to the axially outer side of the omnidirectional wheel 50 will be described in detail with reference to FIGS. 1, 2, 9 to 11, 13, etc.

[0164] First, as mentioned above, an annular retaining plate 61 is abutted against the outer end surface 26 of the wheel member 20 and the outer end surface 31b of the support plate portion 31 of the multiple brackets 30 attached to the wheel member 20, and is fastened to the wheel member 20 and the multiple brackets 30 with bolts or the like.

[0165] The stopper 60 has an overall annular plate-like shape, and is arranged parallel to the retaining plate 61 and is removably attached via locking members (fastening members) such as bolts, pins, screws, etc. inserted into one or more boss members 62 in the direction of the wheel axis.

[0166] The stopper 60 can be switched between two positions, a stopper release position P1 shown in Figures 1 and 9, and a stopper operating position P2 shown in Figures 10 and 11, by changing the position of the boss member 62 in the wheel axis direction.

[0167] 13 and other figures, when the stopper 60 is to be positioned at the stopper release position P1, each boss member 62 is positioned between the stopper 60 and the retaining plate 61 in the wheel axial direction K1, and while the boss members 62 are aligned with the boss holes 60a of the stopper 60 and the boss holes 61b of the retaining plate 61, a locking member such as a bolt is inserted through the boss holes 60a of the stopper 60, each boss member 62, and the boss holes 61b of the retaining plate 61, and inserted (screwed) into the locking holes (screw holes) 26a opening in the outer end surface 26 of the wheel member 20. In this way, the stopper 60 is fixed to the wheel member 20 when positioned at the stopper release position P1.

[0168] The stopper 60 at the stopper release position P1 is located at a position K3 outside the stop plate 61 that abuts against the outer end surface 26 of the wheel member 20, by the length of the boss member 62 in the wheel axis direction K1. In other words, at this time, the boss member 62 functions as a spacer that holds the stopper 60 at a position a certain distance away from the wheel member 20 (stop plate 61).

[0169] 10 and 11 , when the stopper 60 is to be positioned at the stopper action position P2, each boss member 62 is positioned outside the stopper 60 at a position K3 in the wheel axis direction K1, and while the boss holes 60a of the stopper 60 and the boss holes 61b of the stopper plate 61 are aligned, a locking member such as a bolt is inserted through each boss member 62, the boss holes 60a of the stopper 60, and the boss holes 61b of the stopper plate 61, and inserted (screwed) into the locking hole (screw hole) 26a opening in the outer end surface 26 of the wheel member 20. In this way, the stopper 60 is fixed to the wheel member 20 when positioned at the stopper action position P2.

[0170] When the stopper 60 is positioned at the stopper action position P2 and engaged with the wheel member 20 by an engaging member inserted into the boss member 62, the boss member 62 is not interposed between the stopper 60 and the retaining plate 61, and the stopper 60 is close to or abuts against the retaining plate 61, and is therefore fixed to the wheel member 20 in a state close to the outer end surface 26 of the wheel member 20.

[0171] The stopper 60 is aligned with the wheel axis center line Xw of the omnidirectional wheel 50, whether in the stopper release position P1 or the stopper engagement position P2. As shown in Figure 11, the diameter of the stopper 60 about the axis is set so that, when the stopper 60 is in the stopper engagement position P2, its outer peripheral edge can enter the gap G (see Figures 9 and 11, etc.) between the lug 45X (the axial side surface 45b) closest to the wheel member 20 and the adjacent lug 45Xa (the axial side surface 45b) of each of the multiple rollers 40.

[0172] Note that here, the lug 45X close to the wheel member 20 refers to one or more lugs 45 that have entered the gap between the support plate portions 31 of adjacent brackets 30 (the above-mentioned first bracket 30A and second bracket 30B shown in FIG. 4). If the width of the support plate portion 31 in the wheel axis direction K1 is wide, multiple lugs 45 can enter the gap between the support plate portions 31 and become the lug 45X close to the outer periphery 21 of the wheel member 20. In this embodiment, as can be seen from FIG. 9 and other figures, multiple lugs 45 (for example, about 3 to 5 lugs in the example of FIG. 9) become the lugs 45X.

[0173] On the other hand, the adjacent lug 45Xa here means a lug 45 that is adjacent to (one of) the lugs 45X but has not yet entered between the support plate portions 31.

[0174] With the above configuration, the outer peripheral edge of the stopper 60 at the stopper release position P1 is located outside the gap G between the lug 45X of each roller 40 and the adjacent lug 45Xa in the wheel axis direction K3, and does not enter the gap G. Therefore, the rollers 40 of the omnidirectional wheel 50 are free to rotate in the roller rotation direction (along the roller circumference line Cr) from the stopper 60 at the stopper release position P1.

[0175] Meanwhile, the outer peripheral edge of the stopper 60 in the stopper action position P2 fits into the gap G between the lug 45X of each roller 40 and the adjacent lug 45Xa, preventing rotation in the roller rotation direction of the roller 40. In other words, by positioning the stopper 60 in the stopper action position P2, the roller 40 will no longer rotate in a roller rotation direction different from (intersecting with) the wheel rotation direction, and the omnidirectional wheel 50 will be in a normal wheel state that is rotatable only in the wheel rotation direction (the direction of travel of the work vehicle 100).

[0176] Next, a procedure for arranging the plurality of brackets 30 and the plurality of rollers 40 along the outer periphery of the wheel member 20 and the configuration of at least one combined roller 40H included in the plurality of rollers 40 will be described.

[0177] In the following, in this procedure, the bracket 30 that is attached to the wheel member 20 first will be referred to as the "first bracket 30," the bracket 30 that is attached to the wheel member 20 Nth (an integer greater than or equal to 2) time will be referred to as the "Nth bracket 30," the roller 40 that is attached to the bracket 30 first will be referred to as the "first roller 40," the roller 40 that is attached to the bracket 30 Nth (an integer greater than or equal to 2) time will be referred to as the "Nth roller 40," etc.

[0178] First, as shown in Figure 14, the base end 31a of the first bracket 30 (hereinafter referred to as the "first bracket 30F") is fitted into the groove 23 of the wheel member 20, thereby attaching the first bracket 30F to the outer periphery 21 of the wheel member 20.

[0179] Here, preferably, the first bracket 30F attached to the wheel member 20 is held in a state where it is positioned above the wheel member 20, i.e., with the support plate portion 31 on the lower side and the bent portion 32 on the upper side.

[0180] Next, as shown in Figure 14, the first roller 40 (hereinafter referred to as the "first roller 40F") is placed on the convex portion 32b side of the first bracket 30F, and the convex portion 32b of the first bracket 30F is inserted into the bracket insertion recess 40c on the first end 40a side (large diameter side).

[0181] 13, the open end of the second shaft support recess 32d of the first bracket 30F on the surface of the protrusion 32b is aligned with the open end of the shaft hole 40d of the first roller 40F on the first end 40a side (in the bracket insertion recess 40c). At this time, the roller shaft 41 has not yet been provided on the first roller 40F.

[0182] In this way, after the first end 40a side of the first roller 40 is positioned relative to the convex portion 32b of the first bracket 30F attached to the wheel member 20, the second bracket 30 (hereinafter referred to as the "second bracket 30S") is attached to the wheel member 20 on the second end 40b side of the first roller 40F.

[0183] In this case, referring to the representative bracket 30X shown in Figure 13, the second bracket 30S attached to the wheel member 20 is arranged so that the bent portion 32 is aligned along the tapered second end 40b of the first roller 40, and the open end of the shaft core hole 40d of the first roller 40F on the second end 40b side is aligned with the open end of the first shaft support recess (through hole) 32c of the second bracket 30 on the roller 40 side (in the roller insertion recess 32a).

[0184] In this way, with the shaft core hole 40d of the first roller 40F aligned with the second shaft support recess 32d of the first bracket 30F and the first shaft support recess 32c of the second bracket 30S, the first end 41a of the roller shaft 41 is inserted into the first shaft support recess (through hole) 32c of the second bracket 30S from the convex portion 32b side of the second bracket 30S (see representative bracket 30X shown in Figure 13).

[0185] Eventually, the first end 41a of the roller shaft 41 is inserted further, passing through the shaft hole 40d of the first roller 40F and into the second shaft support recess 32d of the first bracket 30F, and eventually comes into contact with the innermost end of the second shaft support recess 32d of the first bracket 30F, completing the insertion.

[0186] At this time, the second end 41b of the roller shaft 41 enters the first shaft support recess (through hole) 32c of the second bracket 30S and does not protrude (extend) beyond the opening end of the surface of the convex portion 32b of the first shaft support recess (through hole) 32c.

[0187] In this state, in order to prevent the roller shaft 41 from slipping out, a stop plate 33 is attached and fixed to the convex portion 32b of the second bracket 30S (see representative bracket 30X in FIG. 13 ) by fastening with bolts, screws, etc. so as to close the open end of the first shaft support recess (through hole) 32c on the convex portion 32b side. Note that by closing the open end of the first shaft support recess 32c on the convex portion 32b side with the stop plate 33 in this way, the first shaft support recess 32c becomes a recess that is open only on the roller insertion recess 32a side.

[0188] The first bracket 30F corresponds to the second bracket 30H2 (see Figures 6 and 16) described below, which supports the combined roller 40H, which is the last roller 40, on the second side in the wheel rotation direction Cw. Therefore, the roller shaft 41 is not inserted into the first shaft support recess (through hole) 32c from the protrusion 32b side, but the second shaft member 41d described below is inserted into the first shaft support recess (through hole) 32c from the roller insertion recess 32a side.

[0189] Therefore, for the first bracket 30F, the opening end of the first shaft support recess (through hole) 32c on the protrusion 32b side is closed by the stop plate 33 before the first roller 40F is assembled.

[0190] In this way, the first roller 40F is supported so as to be freely rotatable in the roller rotation direction around the roller axis line Xr between the bracket 30 (first bracket 30F) attached to the wheel member 20 first and the bracket 30 (second bracket 30S) attached to the wheel member 20 second, with the roller axis 41 defining the roller axis line Xr supported at both ends by the first bracket 30F and the second bracket 30S.

[0191] Next, the second roller 40 (see second roller 40B in FIG. 13 ) is placed on the convex portion 32 b side of the second bracket 30 (see representative bracket 30X in FIG. 13 ), and the convex portion 32 b of the second bracket 30 is inserted into the bracket insertion recess 40 c of the first end 40 a of the second roller 40 (which does not have a roller shaft 41 at this stage), starting the process of supporting the second roller 40 between the second bracket 30 and the bracket 30 (third bracket 30) that is to be attached to the wheel member 20 thirdly. Thereafter, the process of supporting the first roller 40 between the first bracket 30 and the second bracket 30 described above is replaced with the process of supporting the second roller 40 between the second bracket 30 and the third bracket 30, and is repeated.

[0192] Thereafter, the above-mentioned process is repeated, so that the plurality of brackets 30 are sequentially attached to the wheel member 20, and the plurality of rollers 40 and their respective roller shafts 41 are sequentially attached (supported) to the plurality of brackets 30.

[0193] That is, after one roller 40 is arranged along the outer periphery 21 of the wheel member 20, other rollers 40 are sequentially arranged on one end side of the roller 40 in the axial direction Xr, so that a row of multiple rollers 40 is formed in the wheel rotation direction (first rotation direction) Cw.

[0194] At the start of the process of inserting the roller shaft 41 into each roller 40, the next roller 40 has not yet been provided on the side of the convex portion 32b of the bracket 30 supporting the second end 40b of that roller 40, so space is secured on the side of the convex portion 32b of the bracket 30 to align the roller shaft 41 with the first shaft support recess (through hole) 32c of the bracket 30 before inserting the roller shaft 41 into the open end on the convex portion 32b side of the first shaft support recess (through hole) 32c.

[0195] However, the last roller 40 is positioned between the first bracket 30 and the last bracket 30, and in this state, the open end on the convex portion 32b side of the first shaft support recess (through hole) 32c of the first bracket 30, which aligns with the second end portion 40b of the last roller 40, opens within the bracket insertion recess 40c of the first roller 40.In other words, the open end is covered by the outer periphery of the first roller 40, and there is no space in the first shaft support recess (through hole) 32c of the first bracket 30 to center the roller shaft 41 for the last roller 40.

[0196] Therefore, at least for the roller axle 41 of the last roller 40, a configuration of the roller 40 and an assembly procedure are required that allow the roller axle 41 to be assembled to the last roller 40 in a manner other than inserting the roller axle 41 through the first axle support recess 32c of the (first) bracket 30 along the second end of the roller 40.

[0197] Therefore, in this embodiment, as shown in Figures 1, 2, etc., the multiple rollers 40 include at least one (single in this embodiment) combined roller 40H, and the combined roller 40H includes at least the last roller 40 (the roller 40 last supported by the bracket 30).

[0198] The configuration of the combined roller 40H will be described in detail below.

[0199] As shown in FIGS. 1 and 2, the cylindrical main body 42 of the combined roller 40H is formed by combining a first member 42A and a second member 42B.

[0200] That is, the main body 42 of the combination roller 40H is divided into a first member 42A including a core pillar material 43A that is a part of the core pillar material 43 and an outer material 44A that is a part of the outer material 44, and a second member 42B including a core pillar material 43B that is the other part of the core pillar material 43 and an outer material 44B that is the other part of the outer material 44, as shown in Figures 6, 15, 16, etc.

[0201] In other words, by combining the first member 42A and the second member 42B, the core pillar material 43A and the core pillar material 43B are joined to form an integrated core pillar material 43, and the outer casing material 44A and the outer casing material 44B are joined to form an integrated outer casing material 44, thereby forming the main body 42 of the combination roller 40H.

[0202] The main body 42H of the roller 40H may be divided into the first member 42A and the second member 42B in any manner suitable for assembling the roller shaft 41 to the last roller 40. As a suitable example, it is considered that both the first member 42A and the second member 42B have lugs 45 having top end surfaces 45a that become the ground contact portions in the roller 40.

[0203] That is, in this example, the main body 42 of the combined roller 40H is formed by combining a first member 42A having a ground contact portion (top end surface of the lug 45) 45a and a second member 42B having a ground contact portion (top end surface of the lug 45) 45a. In the combined roller 40H configured in this manner, the ground contact portion 45a of the first member 42A and the ground contact portion 45a of the second member 42B are connected in the roller rotation direction (second rotation direction) Cr, thereby forming a lug row 45L (i.e., a row of ground contact portions 45a) similar to the lug row 45L (i.e., a row of ground contact portions 45a) of rollers 40 other than the combined roller 40H (see Figure 2, etc.).

[0204] To realize the combined roller 40H having such a configuration, in this embodiment, the main body 42 is divided into a first member 42A and a second member 42B by a plane including the shaft hole 40d that extends the entire length from the opening end on the first end 40a side to the opening end on the second end 40b side, as shown in Figures 15 and 16. Therefore, the first member 42A and the second member 42B are symmetrical to each other.

[0205] The relative positions of the first member 42A and the second member 42B relative to each other and their relative positions relative to the wheel member 20, etc. change as the combined roller 40H rotates in the roller rotation direction Cr in the completed omnidirectional wheel 50. In this embodiment, however, as shown in FIG. 15, when the combined roller 40H is finally assembled into the row of multiple rollers 40 along the outer periphery of the wheel member 20, the member positioned on the side facing the outer periphery 21 of the wheel member 20 is the first member 42A, and the member positioned on the side farther from the outer periphery 21 of the wheel member is the second member 42B.

[0206] It is not necessary to form the first member 42A and the second member 42B by dividing the main body 42 in half in this manner, and for example, the first member 42A may account for X% (0<X<100) of the entire main body 42, and the second member 42B may account for (100-N)% of the main body 42. Furthermore, the main body 42 of the combination roller 40H may be formed by combining three or more divided members.

[0207] A specific structure for joining the first member 42A and the second member 42B to form the integral main body 42 in this embodiment will be described with reference to FIGS. 15 and 16. FIG.

[0208] As shown in Fig. 16, a positioning recess 43a and a positioning protrusion 43b are formed on the joint surface (open upward in Fig. 16) of the core pillar material 43A of the first member 42A. A positioning protrusion corresponding to the recess 43a of the core pillar material 43A and a positioning protrusion corresponding to the protrusion 43b of the core pillar material 43A are formed on the joint surface (open downward in Fig. 16) of the core pillar material 43B of the second member 42B.

[0209] Furthermore, a pair of screw holes 43c, 43d are drilled in the core pillar material 43A of the first member 42A. A pair of screw holes 43c, 43d corresponding to the screw holes 43c, 43d of the core pillar material 43A are drilled in the core pillar material 43B of the second member 42B.

[0210] The outer material 44B of the second member 42B has a boss hole 44c that is coaxially connected to one of a pair of screw holes in the core column material 43B (in this embodiment, the screw hole with the core column material 43B corresponding to the screw hole 43c in the core column material 43A), and opens on the outer surface of the outer material 44B, as shown in Figures 1, 2, 16, etc.

[0211] In addition, the outer casing material 44A of the first member 42A also has a boss hole that is coaxially connected to one of the pair of screw holes 43c, 43d of the core pillar material 43A (screw hole 43d in this embodiment), and opens on the outer surface of the outer casing material 44A, similar to the boss hole 44c of the outer casing material 44B.

[0212] The first member 42A and the second member 42B abut against each other while being aligned with each other by fitting the convex portion of the core pillar material 43B of the second member 42B into the concave portion 43a of the core pillar material 43A of the first member 42A, and fitting the convex portion 43b of the core pillar material 43A of the first member 42A into the concave portion of the core pillar material 43B of the second member 42B.

[0213] At this time, the boss hole 44c of the outer material 44B of the second member 42B and the screw hole of the core column material 43B connected thereto are coaxially connected to the corresponding screw hole 43c of the core column material 43A of the first member 42A, and the boss hole of the outer material 44A of the first member 42A and the screw hole 43d of the core column material 43A connected thereto are coaxially connected to the corresponding screw hole of the core column material 43B of the second member 42B.

[0214] After this, a bolt (or screw) is screwed into the screw hole of the core column material 43B and the screw hole 43c of the core column material 43A of the first member 42A that communicates with it, via the boss hole 44c of the outer material 44B of the second member 42B, and another bolt (or screw) is screwed into the screw hole 43d of the core column material 43A and the screw hole of the core column material 43B of the second member 42B that communicates with it, via the boss hole of the outer material 44A of the first member 42A, thereby fastening the first member 42A and the second member 42B together, and the main body 42 of the combination roller 40H is completed.

[0215] The procedure for completing the main body 42 of the combined roller 40H as described above is carried out as a "combined roller completion process" described later in the manufacturing process of the omnidirectional wheel 50.

[0216] In the assembly process of the combination roller 40H, before joining the first member 42A and the second member 42B to form the main body 42, it is necessary to incorporate the roller shaft 41 of the combination roller 40H into one of the first member 42A and the second member 42B (in this embodiment, the first member 42A).

[0217] The procedure for assembling the roller shaft 41 of the combined roller 40H in this manner is carried out as a "roller shaft assembling process" described later in the manufacturing process of the omnidirectional wheel 50.

[0218] The manufacturing process of the omnidirectional wheel 50, including the "roller shaft assembly process" and the "combined roller completion process," will be described in detail later.

[0219] The structure of the main body 42 of the combined roller 40H has been described above. Next, the roller shaft 41 of the combined roller 40H will be described in detail.

[0220] As shown in FIGS. 6, 15, 16, etc., the roller shaft 41 of the combined roller 40H includes a first shaft member 41c and a second shaft member 41d that are separate and arranged on the same axis.

[0221] That is, as described above, the roller shaft 41 of each of the rollers 40 has a first end 41 a and a second end 41 b that face each other in the axial direction Xr. In the case of the roller shaft 41 of the combined roller 40H, the tip of the first shaft member 41 c is the first end 41 a, and the tip of the second shaft member 41 d is the second end 41 b.

[0222] As shown in Figures 6, 15, and 16, the combination roller 40H, like the other rollers 40, is supported by one bracket 30 (referred to as the "first bracket 30H1") on one side of the wheel rotation direction (first rotation direction) along the wheel circumference line Cw shown in Figure 1 etc., and is supported by another bracket 30 (referred to as the "second bracket 30H2") on the other side of the wheel rotation direction (first rotation direction).

[0223] In such a combined roller 40H, the first shaft member 41c of the roller shaft 41 is inserted into the second shaft support recess 32d of the first bracket 30H1, and the second shaft member 41d is inserted into the first shaft support recess 32c of the second bracket 30H2.

[0224] In this embodiment, the sum of the overall length of the first shaft member 41c and the overall length of the second shaft member 41d in the direction of the roller axis Xr is smaller than the length (overall length) of the entire roller shaft 41 in the direction of the roller axis Xr. In other words, within the shaft hole 40d of the combined roller 40H, there is a certain distance between the first shaft member 41c of the roller shaft 41 inserted in the second shaft support recess 32d of the first bracket 30H1 and the second shaft member 41d inserted in the first shaft support recess 32c of the second bracket 30H2.

[0225] A spacer shaft 41e is provided in the shaft hole 40d to fill this gap. That is, in this embodiment, the roller shaft 41 of the combined roller 40H is made up of a first shaft member 41c inserted into the second shaft support recess 32d of the first bracket 30H1, a second shaft member 41d inserted into the first shaft support recess 32c of the second bracket 30H2, and a spacer shaft 41e interposed between the first shaft member 41c and the second shaft member 41d.

[0226] Here, the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e may be independent members that are not connected to one another. More specifically, even if they abut against one another, they do not need to be in contact in a manner that transmits the rotation of one to the other.

[0227] In other words, what is required of the spacer shaft 41e is to approximately fix the positions of the first shaft member 41c and the second shaft member 41d in the direction of the roller axis core Xr so as to keep the first shaft member 41c inserted in the second shaft support recess 32d of the first bracket 30H1 and keep the second shaft member 41d inserted in the first shaft support recess 32c of the second bracket 30H2.

[0228] Therefore, if the positions of the first shaft member 41 c and the second shaft member 41 d in the direction of the roller axis Xr can be substantially fixed in this manner, the spacer shaft 41 e does not need to be provided between the first shaft member 41 c and the second shaft member 41 d. For example, within the shaft hole 40 d, a wall portion may be formed on the main body 42 (core post member 43) that prevents the first shaft member 41 c and the second shaft member 41 d from moving inward in the direction of the roller axis Xr (in the direction toward each other).

[0229] In addition, instead of the spacer shaft 41e, a portion similar to the spacer shaft 41e may be formed, for example, in the middle of the second portion 40d2 of the shaft hole 40d in the core pillar material 43B of the second member 42B, and when the second member 42B is assembled to the first member 42A, this portion may fit into the space between the first shaft member 41c and the second shaft member 41d that have already been inserted in the first portion 40d1 of the shaft hole 40d of the first member 42A.

[0230] 6, 15, and 16, flanged bushings 46 are provided at both axial ends of the shaft hole 40d of the combined roller 40H as bearing members interposed between the outer circumferential surface of the roller shaft 41 and the inner circumferential surface of the main body 42 (core post material 43), similar to rollers 40 other than the combined roller 40H. A first shaft member 41c is inserted into the bushing 46 at the opening end of the shaft hole 40d on the first end 40a side, and a second shaft member 41d is inserted into the bushing 46 at the opening end of the shaft hole 40d on the second end 40b side.

[0231] Next, the process of incorporating the combined roller 40H as the last roller 40 into the row of rollers 40 of the omnidirectional wheel 50 and completing the combined roller 40H will be described with reference to FIGS. 15 and 16.

[0232] For ease of explanation, the entity that performs the process or work may be described as the "manufacturer" of the omnidirectional wheel 50.

[0233] In the manufacturing process of the omnidirectional wheel 50, as described above, one roller 40 is arranged along the outer periphery 21 of the wheel member 20, and then other rollers 40 are sequentially arranged on one end side of the roller 40 in the axial direction Xr, thereby forming a row of rollers 40 in the wheel rotation direction (first rotation direction) Cw. This process of sequentially arranging rollers 40 to form a row of rollers 40 is referred to as the "roller arrangement process."

[0234] In this roller arranging step, the combined roller 40H is assembled last into the row, with the main body 42 missing at least one of the first member 42A and the second member 42B.

[0235] In this embodiment, when assembling the combined roller 40H, which is the last roller 40, into the row, as shown in FIG. 15, the space between the first bracket 30 (corresponding to the second bracket 30H2) for assembling the last roller 40 (combined roller 40H) and the last bracket 30 (corresponding to the first bracket 30H1) is positioned above the wheel member 20, and first, the first member 42A, which at this stage corresponds to approximately the lower half of the combined roller 40H, is assembled into this space.

[0236] That is, the combined roller 40H is finally assembled into the row of rollers 40 in the wheel rotation direction Cw, without the second member 42B, which corresponds to approximately the upper half of the combined roller 40H, at this stage.

[0237] Here, the first member 42A of the main body 42 of the combination roller 40H is positioned between the first bracket 30 (corresponding to the second bracket 30H2) and the last bracket 30 (corresponding to the first bracket 30H1) by inserting the convex portion 32b of the last bracket 30 (first bracket 30H1) into the bracket insertion recess 40c on the first end 40a side and inserting the second end 40b into the roller insertion recess 32a of the first bracket 30 (second bracket 30H2).

[0238] At this time, the contact surface of the first member 42A (consisting of a core pillar material 43A and an exterior material 44A) that contacts the second member 42B when the main body 42 is constructed is open (exposed) upward, including the first portion 40d1 of the axial hole 40d that is included in the first member 42A.

[0239] In other words, at this time, because the second member 42B is missing, space is created above the contact surface of the first member 42A, and by utilizing this space, the manufacturer of the omnidirectional wheel 50 can easily insert the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e into the first part 40d1 of the shaft hole 40d.

[0240] Depending on the manufacturing site conditions for the omnidirectional wheel 50, it may be easier to work if the space created by the absence of the second member 42B is located to the side of the first member 42A rather than above it. In such a case, the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e may be inserted with the contact surface of the first member 42A open to the side.

[0241] That is, when the main body 42 is missing the second member 42B of the first member 42A and the second member 42B, and the combined roller 40H is finally assembled into a row of multiple rollers 40, the manufacturer simply positions the first member 42A in the appropriate direction between the last bracket 30 (first bracket 30H1) and the first bracket 30 (second bracket 30H2).

[0242] After this, a "roller shaft incorporation process" is carried out in which the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e are fitted into the first portion 40d1 of the shaft hole 40d, and a "combined roller completion process" is carried out in which the missing second member 42B is combined with the first member 42A to complete the combined roller 40H, which is the last roller 40. These processes will be described in detail below.

[0243] First, as described above, in the first member 42A arranged between the last bracket 30 (first bracket 30H1) and the first bracket 30 (second bracket 30H2), the roller shaft assembly process is carried out in a state in which the first portion 40d1 of the shaft hole 40d is open upward.

[0244] In the roller shaft installation process, the first shaft member 41c and the second shaft member 41d are fitted (inserted) into the first portion 40d1, which is open upward. At this time, within the first portion 40d1 of the shaft hole 40d, the second shaft member 41d is positioned closer to the second end 40b than the first shaft member 41c in the direction of the roller shaft core Xr of the combined roller 40H.

[0245] Next, the first shaft member 41c inserted into the first portion 40d1 of the shaft hole 40d is slid outward toward the first end 40a along the roller axis line Xr, protruding from the opening end of the first portion 40d1 of the shaft hole 40d on the first end 40a side, and inserted into the second shaft support recess 32d of the last bracket 30 (first bracket 30H1).

[0246] On the other hand, the second shaft member 41d fitted into the first portion 40d1 of the shaft hole 40d is slid outward toward the second end 40b along the roller axis line Xr, protruding from the open end of the first portion 40d1 of the shaft hole 40d on the second end 40b side, and inserted into the first shaft support recess 32c of the first bracket 30 (second bracket 30H2).

[0247] In this way, the first shaft member 41c is inserted into the second shaft support recess 32d of the last bracket 30 (first bracket 30H1), and the second shaft member 41h2 is inserted into the first shaft support recess 32c of the first bracket 30 (second bracket 30H2), and the first shaft member 41c and the second shaft member 41d are positioned in the direction of the roller axis Xr.Then, the spacer shaft 41e is fitted into the first part 40d1 of the shaft hole 40d so as to fill the space between the first shaft member 41c and the second shaft member 41d within the first part 40d1 of the shaft hole 40d.

[0248] This maintains the state in which the first shaft member 41c is inserted into the second shaft support recess 32d of the last bracket 30 (first bracket 30H1) and the state in which the second shaft member 41d is inserted into the first shaft support recess 3c of the first bracket 30 (second bracket 30H2).

[0249] As a result of undergoing the roller shaft assembly process, which is the process of fitting the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e as described above, the first member 42A is supported on the first end 40a side by the last bracket 30 (first bracket 30H1) via the first shaft member 41c, and on the second end 40b side by the first bracket 30 (second bracket 30H2) via the second shaft member 41d, i.e., it is supported at both ends by the last bracket 30 (first bracket 30H1) and the first bracket 30 (second bracket 30H2).

[0250] After the first member 42A is thus supported at both ends, as described above, the second member 42B is joined to the first member 42A by engaging the recessed portion 43a and the protruding portion 43b of the first member 42A with the protruding portion and the recessed portion of the second member 42B, and further, as described above, the first member 42A and the second member 42B are fastened together by inserting bolts or the like into the boss hole 44c, the screw holes 43c, 43d, etc., and the final roller 40, the combined roller 40H, is completed.

[0251] As shown in Figure 16, the second member 42B has a second portion 40d2, which is the remaining portion of the shaft hole 40d excluding the first portion 40d1, and by assembling the second member 42B to the first member 42A as described above, the second portion 40d2 is combined with the first portion 40d1, and the shaft hole 40d is also completed so as to surround the roller shaft 41 of the combined roller 40H, which is composed of the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e.

[0252] As described above, by carrying out the roller arranging step, the roller shaft incorporating step, and the combined roller completing step, a row of all the rollers 40 including the combined roller 40H as the last roller 40 is completed.

[0253] Among these, the roller arrangement process is a process in which one roller 40 is arranged along the outer periphery 21 of the wheel member 20, and then other rollers 40 are sequentially arranged on one end side of the roller 40 in the axial direction Xr to form a row of multiple rollers 40 in the wheel rotation direction (first rotation direction) Cw, and finally, the combined roller 40H is incorporated into the row in a state in which the main body 42 is missing at least one of the first member 42A and the second member 42B (in this embodiment, the second member 42B).

[0254] The roller shaft assembly process is a process in which, after the roller arrangement process, the first shaft member 41A is inserted into the second shaft support recess 32d of the first bracket 30H1 and assembled into the combined roller 40H, and the second shaft member 41B is inserted into the first shaft support recess 32c of the second bracket 30H2 and assembled into the combined roller 40H.

[0255] The combined roller completion step is a step of completing the main body 42 of the combined roller 40H by adding the missing first member 42A and / or second member 42B after the roller shaft incorporation step.

[0256] By completing the combined roller 40H, which is the last roller 40, in this manner, all brackets 30 supporting all rollers 40 are provided on the outer periphery 21 of the wheel member 20. After this, for example, a stop plate 61 is fastened to the wheel member 20 and all brackets 30 along the outer end surface 26 of the wheel member 20, and the omnidirectional wheel 50 is completed.

[0257] All the rollers 40 supported along the outer periphery of the wheel member 20 may include a plurality of combined rollers 40H. That is, all the rollers 40 may include combined rollers 40H that are rollers 40 other than the last roller 40, in addition to the combined roller 40H that is the last roller 40. Furthermore, all the rollers 40 may be combined rollers 40H.

[0258] In this way, when the total number of rollers 40 includes a plurality of combined rollers 40H, the procedure for incorporating each combined roller 40H into the row of rollers 40 is the same as the procedure for incorporating the combined roller 40H as the last roller 40 described above.

[0259] That is, first, only the first member 42A as the main body 42, omitting the second member 42B, is placed between two adjacent brackets 30. Then, the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e, which are the roller shafts 41 of the combined roller 40H, are fitted into the exposed first portion 40d1 of the shaft hole 40d of the first member 42A. Thereafter, the missing second member 42B is assembled to the first member 42A so as to cover the first shaft member 41c, the second shaft member 41d, and the spacer shaft 41e fitted into the first portion 40d1 of the shaft hole 40d.

[0260] In this way, with respect to the combined roller 40H, the roller shaft 41 is not inserted into the main body 42 from the open end on the convex portion 32b side of the first shaft support recess (through hole) 32c of the bracket 30 that supports the second end 40b of the combined roller 40H, but rather the first shaft member 41c, second shaft member 41d, and spacer shaft 41e that constitute the roller shaft 41 are fitted into the first portion 40d1 of the shaft core hole 40d that is exposed between the bracket 30 on the first end 40a side and the bracket 30 on the second end 40b side, via the space created by the absence of the second member 42B.

[0261] Therefore, even if another roller 40 has already been assembled to the protrusion 32b of the bracket 30 supporting the second end 40b of the combined roller 40H before the combined roller 40H is assembled, the roller shaft 41 of the combined roller 40H (first shaft member 41c, second shaft member 41d, spacer shaft 41e) can be assembled to the main body 42 of the combined roller 40H, the first end 41a (first shaft member 41c) of the roller shaft 41 can be inserted into the second shaft support recess 32d of one bracket 30, and the second end 41b (second shaft member 41d) of the roller shaft 41 can be inserted into the first shaft support recess 32c of the other bracket 30.

[0262] In other words, for a roller 40 that is a combination roller 40H, the roller shaft 41 can be incorporated into its main body 42 regardless of whether other rollers 40 are already placed on the second end 40b side of the roller 40, i.e., regardless of which roller 40 that is a combination roller 40H is, and it is possible to achieve a state in which the main body 42 is supported at both ends by the brackets 30 on both sides via the roller shaft 41.

[0263] [Omnidirectional Wheel According to Second Embodiment] Hereinafter, an omnidirectional wheel 1 according to a second embodiment will be described with reference to the accompanying Figs. 17 to 33.

[0264] FIG. 17 is a perspective view of the omnidirectional wheel 1. FIG. 18 is an outer side view of the omnidirectional wheel 1. FIG. 19 is an inner side view of the omnidirectional wheel 1. FIG. 20 is a front view of the omnidirectional wheel 1. FIG. 21 is a side cross-sectional view of the omnidirectional wheel 1. FIG. 22 is a front cross-sectional view of the omnidirectional wheel 1 when the stopper 10 is released. FIG. 23 is a front view of the omnidirectional wheel 1 showing the stopper 10 in the stopper release position P1. FIG. 24 is a front cross-sectional view of the omnidirectional wheel when the stopper is activated. FIG. 25 is a front view of the omnidirectional wheel 1 showing the stopper 10 in the stopper activation position P2. FIG. 26 is a front cross-sectional view of the omnidirectional wheel 1 when a stopper 10 with a different configuration is activated.

[0265] FIG. 27 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. 28 is a perspective view of the wheel member 4 with the unit roller assembly R attached. FIG. 29 is an exploded perspective view showing the first roller 6 removed from the bracket 5 attached to the wheel member 4. FIG. 30 is a perspective view of the wheel member 4 with the unit roller assembly R and second roller 7 attached. FIG. 31 is an outer side view of the wheel member 4 with the unit roller assembly R and second roller 7 attached. FIG. 32 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. 33 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.

[0266] 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.

[0267] 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. 17, etc.). As shown in FIG. 20, 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 vehicle body 101 of the work vehicle 100. Therefore, this side K2 of the omnidirectional wheel 1 will be referred to as the "wheel inner side," and the opposite side K3 in the wheel axis center direction K1 will be referred to as the "wheel outer side."

[0268] 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. 17, etc.).

[0269] It should be noted 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.

[0270] The omnidirectional wheel 1 has a plurality of rollers 6, 7 that are rotatable in a direction different from the rotational direction (wheel rotation direction) on the outer periphery of the wheel member 4. The rollers 6, 7 are arranged radially around the hub 2. Each of the 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).

[0271] The plurality of rollers 6, 7 include a plurality of first rollers 6 and a plurality of second rollers 7. The plurality of first rollers 6 and the plurality of second rollers 7 are provided with protrusions (lugs) 6 a, 7 a on their outer peripheries. As will be described in detail later, the first roller 6 has a plurality of lugs 6 a radially arranged on the outer periphery of the first roller 6, and the second roller 7 has a single flange-shaped lug 7 a extending along the outer periphery of the second roller 7.

[0272] As shown in Figures 18, 19, 21, etc., the omnidirectional wheel 1 has multiple brackets 5 arranged at intervals on the outer periphery (outer periphery) of the wheel member 4. Pairs of multiple first rollers 6 are rotatably supported on both sides (support portions 5a) of each bracket 5. Specifically, multiple second rollers 7 are rotatably supported on separate adjacent brackets 5. In other words, each of the multiple second rollers 7 is not located between a pair of first rollers 6 supported on a common bracket 5, but is located 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 first bracket 5.

[0273] As shown in Figures 23 and 25, the first roller 6 has a plurality of radially arranged lugs 6a, each pair of which is arranged point-symmetrically around the roller axis Xr1. Therefore, as shown in Figures 21, 23, 25, 31, and so on, 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 Figures 21 and 31, 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 Figures 21 and 31, 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 will sometimes be referred to as the large-diameter roller, and the second roller 7 will sometimes be referred to as the small-diameter roller.

[0274] The brackets 5 are provided so as 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.

[0275] A pair of first rollers 6 is supported by each bracket 5, and the second rollers 7 are respectively disposed in the gaps between the first rollers 6. Therefore, the plurality of brackets 5, the plurality of first rollers 6, and the plurality of 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).

[0276] 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.

[0277] As shown in Figure 31 and other figures, 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."

[0278] Furthermore, the axis of the rollers 6 and 7, which is formed by integrating the first roller axis Xr1 and the second roller axis Xr2, is referred to as the "roller axis Xr" (see Figures 22 to 25, 28, 31, etc.), and the direction along the roller axis Xr is sometimes referred to as the "roller axis direction."

[0279] The first roller 6 rotates 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." The direction of rotation along the first roller circumferential line Cr1 is referred to as the "first roller rotation direction" (see, for example, Figure 28).

[0280] 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. 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, for example, Figure 30).

[0281] Furthermore, the circumferential line of the rollers 6, 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 the rollers 6, 7 along the roller circumferential line Cr is sometimes referred to as the "roller rotation direction" (see Figures 17, 22 to 25, etc.).

[0282] 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 number of grooves 4a are radially protruded from the wheel member 4 as described above (see FIG. 21, etc.). The plurality of grooves 4a are formed at equal intervals in the circumferential direction of the wheel member 4.

[0283] As can be seen in Figure 28, 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.

[0284] As shown in Figures 19, 20, 22 to 25, 28 to 30, 32, etc., a flange 4b ​​is provided at the wheel inboard side K2 end of the wheel member 4. As shown in Figures 19, 20, 22 to 25, a flange 2a is also formed on the hub 2. The wheel inboard side K2 end face of the flange 4b ​​of the wheel member 4 abuts against the wheel outboard side K3 end face of the flange 2a of the hub 2. In addition, the wheel inboard side K2 end of the bracket 5 attached to the wheel member 4 abuts against the wheel outboard side 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 bracket 5 together via the flange 4b ​​with a fastening member (e.g., a bolt).

[0285] Additionally, a stay portion 5d (see FIGS. 21 and 33) formed at the wheel inner side K2 end of the bracket 5 abuts against the wheel outer side K3 end face of the flange 4b ​​of the wheel member 4. The bracket 5 is fixed to the wheel member 4 by fastening the stay portion 5d to the flange 4b ​​with a fastening member (e.g., a bolt). 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.

[0286] 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 22 to 25, 28 to 30, etc.) of the wheel member 4. As shown in Figures 22 to 25, 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).

[0287] 22, 24, 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 32 and 33, 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.

[0288] 29, 32, 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. 21, 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.

[0289] 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, compared 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, i.e., a gap 6s is formed between the lugs 6a on the outer circumferential surface.

[0290] 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 18, 19, etc.).

[0291] 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 21 and 31, 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.

[0292] However, there is only a small difference in diameter between the first end and the second end of the lug 6 a of the first roller 6 in the first roller axial direction. Therefore, the multiple lugs 6 a 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.

[0293] 21 and other figures, 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.

[0294] When the second roller 7 disposed in this position is viewed along the wheel axis Xw, the end of the second roller 7 facing the first roller 6 is located inside the first roller 6 and overlaps 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 the maximum diameter L2, forms the aforementioned lug (second lug) 7a that protrudes circumferentially around the second roller axis Xr2, i.e., in the outer circumferential direction, like a flange. Hereinafter, the flange-shaped intermediate portion 7a and lug 7a may be interchangeably referred to as "lug."

[0295] As shown in Figure 21 and other figures, the second roller 7 has a shaft member 8 that serves as a rotational shaft. In other words, the second roller 7 is provided around each shaft member 8. As shown in Figure 30 and other figures, a bushing 8b is interposed between the shaft member 8 and the second roller 7, allowing the second roller 7 to rotate freely relative to the shaft member 8.

[0296] The second roller 7 has tapered end portions 7b (hereinafter referred to as "tapered end portions") on both sides of the second roller in the axial direction. The tapered end portions 7b have a diameter smaller than that of the intermediate portion 7a. The diameter of the tapered end portions 7b is set according to the inner diameter of the first roller 6.

[0297] 21, 33, etc., both ends of the shaft member 8 protrude as roller center shafts 8a from the center of the tapered end 7b on both sides in the second roller axial direction of the second roller 7. In other words, the second roller 7 has a pair of roller center shafts 8a protruding from both ends in the direction along the outer periphery.

[0298] 21, 23, 25, 28, 29, 32, 33, 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.

[0299] 21, 30, 31, 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.

[0300] 21, 23, 25, 28, 29, 32, 33, 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.

[0301] 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.

[0302] 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 the support portions 5a on both sides in the roller axis direction (wheel rotation direction).

[0303] 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.

[0304] By reducing the dimensions of the first roller 6 and the support portion 5a in the first roller axis direction in this way, 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) disposed 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.

[0305] The second rollers 7 rotate around the axle members 8 to facilitate smooth movement of the omnidirectional wheels 1 in the wheel axis direction K1 while in contact with the ground. The large diameter (maximum diameter L2) of the middle portions 7a (lugs 7a), which are the largest diameter portions of the second rollers 7, allows even a small portion of the second rollers 7 to protrude from the soil, enabling the omnidirectional wheels 1 to traverse the soil even when the omnidirectional wheels 1 move in the wheel axis direction K1 on relatively soft soil.

[0306] 17, 18, 22 to 25, 27, 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.

[0307] First, at least one of the rollers 6, 7 of the omnidirectional wheel 1 has a hook portion 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 portion 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, which will be described later.

[0308] 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 the stopper 10. In other words, the hooking portion only needs to restrain rotation on one side of the two-way rotation of the roller by abutting against the stopper 10. Therefore, even if the area of ​​the hooking portion of the roller that abuts against the stopper 10 is relatively small, it can sufficiently restrain rotation on that side of the roller.

[0309] 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 protruding from the outer peripheral surface of the roller and capable of contacting the stopper 10 on one side and the other side in the rotational direction of the roller.

[0310] 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 abut against 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 abut against the stopper 10, and by abutting against the stopper 10 as the hook, each lug 6a suppresses at least one of the rotation of the first roller 6 on one side and the other side.

[0311] The stopper 10 is a disc-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 disc-shaped member, enters the gap 6s between the lug 6a1 and lug 6a2 of each first roller 6, the two lugs 6a1, 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 rotational direction of the first roller 6. In this state, regardless of the direction (counterclockwise or clockwise) in which the first roller 6 rotates about the first roller axis Xr1, the outer peripheral edge of the stopper 10 abuts against either the lug 6a1 on one side of the rotational direction or the lug 6a2 on the other side, thereby preventing further rotation of the first roller 6 in that rotational direction. That is, the outer peripheral edge of the stopper 10 that enters the gap 6s restricts the rotation of the first roller 6.

[0312] As shown in Figures 22 and 23, 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, and allows 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, and restricts the rotation of the first roller 6, as shown in Figures 24 and 25.

[0313] 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).

[0314] 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.

[0315] The outer peripheral edge of the stopper 10 at the stopper action position P2 comes into contact with the lug 6a, which is a protruding portion of 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.

[0316] If the length of the gap 6s in the rotation direction of the first roller 6 is relatively tight, the 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 gap 6s between the lugs 6a of the first roller 6 is designed to be relatively tight, 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 no play area for rotation of the first rollers 6 is provided in the gap 6s.

[0317] 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 first roller 6 to rotate is provided in the gap 6s.

[0318] As mentioned above, the concept that the stopper 10 in 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 peripheral 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 a play area is provided in the gap 6s.

[0319] 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.

[0320] 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 rotational direction of the roller, and can more easily cooperate with the stopper 10.

[0321] 18, 19, 21, etc., the rollers 6, 7 of the omnidirectional wheel 1 include two first rollers 6 arranged symmetrically about the wheel axis Xw, which is the rotation axis (hub 2) of the omnidirectional wheel 1. As shown in FIGS. 18, 19, 22 to 25, 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 arranged symmetrically about the point (L3>L4).

[0322] 23 , of the multiple lugs 6 a and gaps 6 s of each first roller 6, two lugs 6 a 1 and 6 a 2 and the gap 6 s between the lugs 6 a 1 and 6 a 2 are closest to the outer circumferential edge of the stopper 10 in the stopper release position P1. Here, in each first roller 6, the lugs 6 a 1 and 6 a 2 and the gap 6 s between the lugs 6 a 1 and 6 a 2 are located closer to the wheel axis X w of the omnidirectional wheel 1 than the first roller axis X r1, i.e., on the side of the first roller 6 facing the outer circumferential surface of the wheel member 4, and are located closer to the wheel outer side K3 than the center of the first roller 6 in the wheel axis direction K1. Therefore, of the multiple lugs 6 a and gaps 6 s of each first roller 6, the lugs 6 a 1 and 6 a 2 and the gap 6 s between the lugs 6 a 1 and 6 a 2 are closest to the outer circumferential edge of the stopper 10, which has a diameter L 4 shorter than the distance L 3 as described above.

[0323] With this configuration, as soon as the stopper 10, which was in the stopper release position P1, moves to the inner side K2 of the wheel and reaches the stopper action position P2, the outer peripheral edge of the stopper 10 enters the gap 6s between the lugs 6a1 and 6a2, as shown in Figure 25.

[0324] When the stopper 10 is in the stopper action position P2, only the outer peripheral edge portion of the stopper 10 that has entered the gap 6s cooperates to restrict the rotation of the first roller 6. On the other hand, of the multiple lugs 6a of the first roller 6, only two lugs 6a1 and 6a2 on one side and the other side in the rotation direction of the first roller abut (or are able to abut) against the outer peripheral edge portion of the stopper 10 that has entered the gap 6s.

[0325] Therefore, in order to restrict the rotation of the first roller 6, the stopper 10 should be positioned so that its outer peripheral edge can abut against the lugs 6a1, 6a2 that are closer to the wheel axis center Xw than the first roller axis center Xr1 in the radial direction from the wheel axis center Xw. This allows the diameter L4 of the stopper 10 to be shortened (L4<L3) as described above, and the stopper 10 can be made smaller.

[0326] On the other hand, for the first roller 6, only two of the multiple lugs 6a, 6a1 and 6a2, are likely to 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 more likely that different first lugs 6a become lugs 6a1 and 6a2 each time the stopper 10 is operating 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.

[0327] Furthermore, when the first roller 6 attempts to rotate in one direction in the first roller rotation direction and comes into contact with the lug 6a1 or 6a2 on that side, 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 exists 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.

[0328] In this embodiment, the first roller 6 has a larger diameter than the second roller 7 and reaches closer to the wheel axle center 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.

[0329] 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 of the stopper 10 to enter the gap 6s between the lugs 6a1 and 6a2 of the first roller 6, thereby allowing the lugs 6a1 and 6a2 of the first roller 6 to serve as latching portions on one and the other sides in the direction of rotation. Therefore, the omnidirectional wheel 1 with such stopper 10 is effective in terms of the aforementioned miniaturization of components, simplification of structure, reduction in cost, and improvement of durability.

[0330] 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 active 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 22 and 24, 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.

[0331] 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 back and forth (relatively movable) in the axial direction, i.e., 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 22 and 23 and a stopper action position (roller rotation preventing position) P2 shown in Figures 24 and 25.

[0332] As described above, in this embodiment, 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 application position P2, for example, a plurality of rod members may be provided protruding from the wheel outer end surface 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.

[0333] 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 Figure 22, 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.

[0334] 22, two spacer nuts 13 are used to position the stopper 10 at the stopper release position P1, but this is not limitative. 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 6 a and 7 a.

[0335] 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.

[0336] In this way, the stopper 10 in 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 in the stopper release position P1, all of the rollers 6 and 7 are free to rotate in the roller rotation direction Cr.

[0337] 24 and 25, 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.

[0338] As described above, the stopper 10 can be switched between a stopper release position P1 in which it is disengaged from the multiple rollers 6, 7 and a stopper engagement position P2 in which it engages the multiple rollers 6 by moving back and forth in a direction along the hub 2 (wheel axis Xw).

[0339] With the above configuration, the stopper 10 in the stopper action position P2 prevents rotation in the roller rotation direction Cr (direction along the first roller circumferential line Cr1) of at least the large-diameter first roller 6 of the rollers 6, 7. With the stopper 10 in the stopper action position P2, the omnidirectional wheel 1 functions 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.

[0340] 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.

[0341] On the other hand, an agricultural vehicle equipped with omnidirectional wheels 1 may repeatedly perform pivot turns and spin turns while traveling through 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 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.

[0342] In addition, in this embodiment, as shown in Figure 25 etc., the stopper 10 moves along the wheel axis Xw to the inner side K2 of the wheel and comes into contact with 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.

[0343] However, there are various possible 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 plate-shaped stopper 10 to abut) 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.

[0344] 26, 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.

[0345] 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 6 a.

[0346] 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.

[0347] 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.

[0348] Therefore, it is conceivable to provide an actuator on the omnidirectional 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) may also be used as the actuator.

[0349] 34 to 36, such a 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.

[0350] Furthermore, when an operator remotely controls work vehicle 100 using terminal device 135, the operator may operate terminal device 135 while taking into account 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.

[0351] The stopper control actuator and the control structure of the actuator in the work vehicle 100 described above can also be applied as an actuator that moves the stopper 60 of the omnidirectional wheel 50, which is the omnidirectional wheel in the first embodiment, and as a control structure of the actuator in the work vehicle 100 when equipped with the omnidirectional wheel 50.

[0352] [Work Vehicle According to Third Embodiment] Next, a work vehicle 100 shown in Figs. 34 to 36 will be described as an example of a work vehicle equipped with omni-directional wheels (omni-wheels) W (work vehicle according to a third embodiment).

[0353] As a diagram showing a work vehicle equipped with omnidirectional wheels W, Fig. 34 is a perspective view showing a work vehicle (tractor) 100 equipped with omnidirectional wheels W making a pivot turn. Fig. 35 is a side view of a work vehicle (tractor) 100 equipped with omnidirectional wheels W. Fig. 36 is a diagram showing the drive / steering system structure of the work vehicle 100.

[0354] The omnidirectional wheel W provided on the work vehicle 100 may be configured to include at least a wheel member (e.g., wheel member 20 or wheel member 4) supported on the work vehicle 100 as a normal wheel so as to be rotatable in a wheel rotation direction (first rotation direction) along the vehicle's traveling direction, and a roller supported along the outer periphery of the wheel member so as to be rotatable in a roller rotation direction (second rotation direction) that intersects (is different from) the wheel rotation direction (first rotation direction), which is the rotation direction of the wheel member. The omnidirectional wheel 50 shown in Figures 1 to 16 (and the omnidirectional wheel 50A in Figure 8) and the omnidirectional wheel 1 shown in Figures 17 to 33 are examples of such omnidirectional wheels W.

[0355] Therefore, the omnidirectional wheel W shown in Figures 34 and 35 has the appearance of the omnidirectional wheel 50 shown in Figures 1 to 16, but this does not mean that the omnidirectional wheel W shown in Figures 34 and 35 is limited to the omnidirectional wheel 50, and may be replaced with, for example, one having the appearance of the omnidirectional wheel 1 shown in Figures 17 to 33.

[0356] The work vehicle 100 shown in Figures 34 to 36 is a tractor to which a work device (implement) can be attached.

[0357] The work vehicle 100 shown in Figures 34 to 36 comprises a vehicle body 101, first wheels 102 which are left and right omnidirectional wheels W 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 on both the left and right sides of the vehicle body 101 in front of or behind the first wheels 102 and driven by the drive unit 105.

[0358] 34 to 36, the second wheel 103 is a tire-type wheel that is a unidirectional wheel that can rotate in one direction (see the wheel rotation direction Cw of the omnidirectional wheel 50 or the omnidirectional wheel 1), unlike the omnidirectional wheel W. Specifically, the second wheel 103 is a unidirectional wheel that can rotate only in the rotation direction of the rotation shaft that supports the second wheel 103, i.e., in the forward and reverse directions.

[0359] The second wheel 103 may be a drive wheel (or drive sprocket) of a crawler-type traveling device. Furthermore, the second wheel 103, which is a drive wheel, may also be an omnidirectional wheel W, and all of the front and rear wheels of the work vehicle 100 may be configured as omnidirectional wheels W. Furthermore, the first wheel 102, which is an omnidirectional wheel W, 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.

[0360] On the other hand, the first wheel 102 is an omnidirectional wheel W. The rotation axis (wheel member 20 of the omnidirectional wheel 50 or hub 2 of the omnidirectional wheel 1) of the first wheel 102 (omnidirectional wheel W) 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 W is not a tire-type wheel because the multiple rollers (roller 40 of the omnidirectional wheel 50 or rollers 6 and 7 of the omnidirectional wheel 1) do not constitute a tire. However, all of the rollers (roller 40 of the omnidirectional wheel 50 or rollers 6 and 7 of the omnidirectional wheel 1) arranged along the outer periphery of the wheel member (wheel member 20 of the omnidirectional wheel 50 or wheel member 4 of the omnidirectional wheel 1) rotate in the wheel rotation direction Cw like a single tire.

[0361] The work vehicle 100 also includes 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. While the work vehicle 100 is turning the body 101 using this first body turning device S1, the rollers (rollers 40, or the first roller 6 and / or the second roller 7) that are in contact with the ground among the multiple rollers of the first wheels 102 (rollers 40 of the omnidirectional wheel 50, or rollers 6, 7 of the omnidirectional wheel 1) 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).

[0362] The work vehicle 100 changes its traveling direction, i.e., turns the vehicle body 101, by using the first vehicle 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 rotating the left and right second wheels 103). The first vehicle 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 vehicle body turning device S1 of the work vehicle 100 can also perform a pivot turn (pivot turn) of the vehicle body 101 by stopping the rotation of one of the left and right second wheels 103 and rotating only the other second wheel 103.

[0363] 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 34. Figure 34 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.

[0364] Due to this rotation of the left and right second wheels 103, the vehicle 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 vehicle 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 aforementioned wheel rotation direction Cw), but a movement along the wheel axis Xw that is perpendicular to the wheel rotation direction Cw.

[0365] In the work vehicle 100 according to this embodiment, an omnidirectional wheel 1 rotatable in a wheel rotation direction Cw (first direction) and a roller rotation direction Cr (second direction) 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.

[0366] 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 directions. This driving device 105 functions as the first vehicle body turning device S1.

[0367] The work vehicle 100 may be equipped 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 brakes 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.

[0368] 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-right direction relative to the vehicle body 101 can be changed, that is, whose turning angle (steering angle) can be changed left and right. 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-right direction relative to the vehicle body 101.

[0369] If 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 also be equipped with such a steering device 120 as a second body turning device S2.

[0370] As will be described in detail later, the work vehicle 100 shown in Figures 35 and 36 is equipped with a drive device 105 for driving the second wheel 103, which is a drive wheel, and a steering device 120 for steering the first wheel 102, which is a steered wheel, and the drive device 105 functions as the first vehicle body turning device S1 and the steering device 120 functions as the second vehicle body turning device S2.

[0371] As shown in Figures 34 to 36, the third embodiment employs a tractor as an agricultural machine capable of mounting an implement as the work vehicle 100 (i.e., wheeled type) having the above configuration. However, the work vehicle 100 equipped with omnidirectional 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 considered as work vehicles for agriculture. Furthermore, a skid steer loader, which is a type of wheel loader, is considered as a work vehicle for construction work. For convenience of explanation, the structure of the work vehicle 100 will be described in detail below using a tractor as an example.

[0372] The work vehicle 100 shown in Figures 34 to 36 has a body 101 (machine body) that supports left and right first wheels 102, which are a left front wheel 102L and a right front wheel 102R, and left and right second wheels 103, which are a left rear wheel 103L and a right rear wheel 103R.

[0373] The vehicle body 101 supports various devices (on-board devices) provided on the work vehicle 100, such as a prime mover 104 and a 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 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 supplied to the electric motor serving as the prime mover 104.

[0374] 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 performing work 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 implement as an agricultural work implement includes a tilling implement for tilling a field, a tilling implement for performing tilling work, 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 performing seed sowing work, a transplanter for planting crops (seedlings), a harvesting implement for harvesting crops, a reaping implement for reaping grass, etc., a spreading implement for spreading grass, etc., a grass collecting implement for collecting grass, etc., a shaping implement for shaping grass, etc. The operator can select a working implement from the various types of working implements described above and couple it to the coupling device 115.

[0375] 34 to 36, 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. 36, 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.

[0376] 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 36. 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.

[0377] 36 , 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), the power of the 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.

[0378] In the vehicle body 101, a PTO transmission mechanism 114 is provided 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 turns on and off the power transmission from the prime mover 104 to the PTO shaft 113, a PTO speed change 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.

[0379] 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.

[0380] 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 Figure 36, 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.

[0381] 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 independently drives the left rear wheel 103L and right rear wheel 103R (left and right second wheels 103), which are the drive wheels. As shown in FIG. 20 , the work vehicle 100 is equipped with a pair of hydrostatic stepless transmissions (hereinafter referred to as "HST") 107, i.e., a left HST 107L and a right HST 107R, as the drive unit 105 having this structure.

[0382] 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.

[0383] The output shaft (motor shaft) of the left travel 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 travel motor 109R is operatively connected to the axle 103a of the right rear wheel 103R, which is the second right wheel 103 (hereinafter, the travel motors 109L and 109R will be collectively referred to as "travel motor 109").

[0384] 36, 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.

[0385] 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. 36 does not illustrate the 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 be omitted 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.

[0386] 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.

[0387] 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 corresponding 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.

[0388] Furthermore, by tilting the movable swash plate 108a from the neutral position in the tilting direction for reverse travel, the travel motor 109 is rotated in the reverse direction at a speed according to the tilt angle of the movable swash plate 108a by the oil flow in the other direction of the discharged oil from the hydraulic pump 108. As a result, the travel motor 109 rotates the second wheel 103 in the reverse direction at that speed.

[0389] Therefore, by providing a difference in tilt angle or tilt direction between the adjustable swash plate 108a of the hydraulic pump 108L of the left HST 107L and the adjustable 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 travel motor 109L and the right travel 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).

[0390] In other words, in the work vehicle 100, the driving device 105 of the traveling system 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 rotational speed and / or rotational direction of the second wheels 103, which are the left and right drive wheels.

[0391] In the work vehicle 100 shown in FIG. 36, pilot pressure oil is applied to the pilot pressure receiving portions of the movable swash plates 108a of the hydraulic pumps 108L, 108R via the corresponding control valves (regulators) included in the control valve unit 112.

[0392] The control valves included in the control valve unit 112 are solenoid valves, and the excitation and de-energization of the solenoids is 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, 108R so that the driving device 105 of the traveling system functions as the first vehicle body turning device S1.

[0393] The control of the movable swash plates 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 plates 108a in the second mode or the third mode, the drive device 105 functions as the first vehicle body turning device S1.

[0394] 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 turning 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.

[0395] 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.

[0396] The processor is, for example, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a field programmable gate array (FPGA), and an application specific integrated circuit (ASIC).

[0397] 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.

[0398] In addition, the software program may be stored on a recording medium (non-volatile memory such as HDD, SSD, CD-ROM, DVD-ROM, etc.) communicatively connected to the control device 110, or on an external server device connected via the above-mentioned network, and installed from there into the above-mentioned memory.

[0399] 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. 36 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.

[0400] When the work vehicle 100 can be operated by a person, a driver's seat is installed in 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.

[0401] 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, 108R are changed, 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).

[0402] In addition, by controlling the control valves by the control device 110 based on signals obtained from the input device 131, for example, the working hydraulic actuator 116 and the 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.

[0403] 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 or 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. 36. Possible patterns for vehicle operation in unmanned operation include automatic operation and remotely controlled operation.

[0404] 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. The control device 110 then issues the determined command to the corresponding control valve in 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 or the like to raise and lower the working device.

[0405] 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 driving 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 or the like to raise and lower the working device.

[0406] 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 example described above, the control device 110 can switch between the first to third modes, but the number and combination of modes are not limited to those in the example described above 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.

[0407] For example, if the work vehicle 100 is provided with a steering device 120 as a second 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.

[0408] Furthermore, the work vehicle 100 does not necessarily have to be provided with the 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. Furthermore, instead of or in addition to the third mode, the control device 110 may be capable of switching to a fourth mode (pilot turning mode) in which the drive device 105 is controlled 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.

[0409] 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 60 or 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 60 or the stopper 10 at the stopper release position P1.

[0410] 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 the running motors 109L, 109R) for driving the left and right second wheels 103 separately, and output from the single output shaft to the differential gear device.

[0411] 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 differentially rotated. However, the differential rotation of the left and right second wheels 103 using such a differential gear device is not a differential rotation for turning the vehicle body 101, but a differential rotation to prevent wheel drag or the like from occurring while the vehicle body 101 is turning, that is, a differential rotation in response to the turning of the vehicle body 101.

[0412] Therefore, when the drive device 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 making the rotational speed and / or rotational direction of the left and right second wheels 103 different.

[0413] Therefore, when the driving device 105 of the running system is configured in this manner, 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 rotational speed and / or rotational direction of the left and right second wheels 103.

[0414] 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.

[0415] 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 (for example, independently controls the inverters provided in the pair of electric motors) so that the pair of electric motors have different rotation speeds and / or rotation directions, and the drive device 105 functions as the first vehicle-body turning device S1.

[0416] 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 travel motors 109 that are hydraulic motors, i.e., 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 inclined plate 108a of the hydraulic pump 108, the travel 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.

[0417] Note that the pair of travel (hydraulic) motors 109 (including those included in HSTs 107L, 107R as shown in FIG. 20 and those that do not constitute an HST as described above) included in the drive device 105 serving as the first vehicle body turning device S1, the pair of electric motors described above, and the like may serve as wheel motors and be mounted inside or outside the wheel members that constitute each of the second wheels 103. In this way, by using the pair of motors (electric motors, hydraulic motors, etc.) for driving the left and right second wheels 103 as wheel motors, the work vehicle 100 can be made more compact.

[0418] The work vehicle 100 shown in Figures 35 and 36 further configures the left and right first wheels 102 (left front wheel 102L, right front wheel 102R), which are omnidirectional wheels W, as steerable wheels with a changeable steering angle. Note that the steering angle is the wheel turning angle, i.e., the left and right rotation angle from the forward and backward straight ahead direction, and as described above, 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.

[0419] 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.

[0420] 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 operator, a steering shaft (stem) 122 that is the rotation axis 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 is actuated by switching the steering valve 123.

[0421] 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, causing the piston rod 125b to slide in the left and right axial directions, thereby turning 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.

[0422] 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.

[0423] 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.

[0424] In this way, in the work vehicle 100 shown in Figure 36, as described above, 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.

[0425] Here, the first wheel 102, which is the steering wheel, is an omnidirectional wheel W (the omnidirectional wheel 50 or the omnidirectional wheel 1). Therefore, the roller of the first wheel 102 that is in contact with the ground (the roller 40 of the omnidirectional wheel 50 or the roller 6 and / or roller 7 of the omnidirectional wheel 1) 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 W, the turning of the vehicle body 101 by the steering device 120 can be smoothed.

[0426] 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 wheels 102 to assist in the turning. In this case, the rotation of the first wheels 102 whose steering angle has been changed in the wheel rotation direction Cw and the rotation of the rollers of the first wheels 102, which are omnidirectional wheels W (the rollers 40 of the omnidirectional wheels 50, or the rollers 6 and / or 7 of the omnidirectional wheels 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.

[0427] 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.

[0428] In this way, when the second wheel 103, which is a drive wheel, is 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 changing 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).

[0429] Furthermore, in the work vehicle 100, when the second wheel 103, which is a drive wheel, is used as a steered wheel, the first wheel 102 may be used as a non-steered wheel, and only the second wheel 103 may be used as 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.

[0430] Furthermore, in the work vehicle 100, the second wheel 103, which is a drive wheel, may be an omnidirectional wheel W (omnidirectional wheel 50 or omnidirectional wheel 1), and further, the second wheel 103, which is both a drive wheel and a steered wheel, may be an omnidirectional wheel W (omnidirectional wheel 50 or omnidirectional wheel 1). In other words, all four wheels of the work vehicle 100 may be drive wheels, steered wheels, and omnidirectional wheels W. Note that 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 W.

[0431] In addition, for a work vehicle 100 equipped with two body turning devices S1 and S2 as shown in Figure 36, 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.

[0432] For example, when work vehicle 100 is being driven by a person, the worker may operate steering handle 121 to select turning of vehicle body 101 by steering left and right first wheels 102 (left front wheel 102L, right front wheel 102R) with steering device 120. Also, the worker may operate a joystick or the like included in input device 131 to select turning of vehicle body 101 by differentially driving left and right second wheels 103 (left rear wheel 103L, right rear wheel 103R) with drive device 105 (HST 107L, 107R).

[0433] Furthermore, 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.

[0434] 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 inclined 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.

[0435] 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., which of the body turning devices S1 and S2 should be used to turn the body 101, or whether the body 101 should be turned using both body turning devices S1 and S2, and based on this determination, etc., the body 101 may be turned using the first body turning device S1 and / or the second body turning device S2.

[0436] [Work vehicle according to fourth embodiment] In the third 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.

[0437] If the work vehicle 100 is equipped only with a 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 rotation 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.

[0438] On the other hand, as mentioned above, if the work vehicle 100 is equipped with a first body turning device S1 that makes the rotation speed and / or rotation direction of the left and right second wheels 103, which are the drive wheels, different (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 as the second body turning device S2.

[0439] Figure 37 is a diagram showing the drive system structure of a work vehicle (tractor) 100 (work vehicle according to a fourth embodiment) equipped with omnidirectional wheels 1. The work vehicle 100 of the fourth embodiment shown in Figure 37 has such a structure.

[0440] The work vehicle 100 in Fig. 37 will be described. Note that members, parts, etc. designated by the same reference numerals as those shown in Fig. 37 are the same as or similar to those designated by the same reference numerals in Fig. 36, and descriptions thereof will be omitted unless otherwise specified.

[0441] In the work vehicle 100 of Figure 37, the drive unit 105, like the drive unit 105 of Figure 36, 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.

[0442] On the other hand, the first wheels 102 (left front wheel 102L, right front wheel 102R) which are omnidirectional wheels W are not steered wheels supported on the vehicle body 101 via knuckle arms 102a. In Figure 37, the first wheels 102 which are omnidirectional wheels W are provided at the outer end of axles 102b which extend in the left-right direction and are rotatably supported on the vehicle body 101, and cannot rotate left or right relative to the vehicle body 101.

[0443] In other words, in the fourth embodiment, when the first wheel 102 is, for example, an omnidirectional wheel 50, the wheel member 20 is not connected to an axle 157 journaled on a steering shaft case 152b that functions as a steering shaft (kingpin) as shown in FIG. 12, but may be directly connected to, for example, a differential yoke shaft 155 protruding from the left and right ends of a differential yoke shaft case 152a shown in FIG. 12.

[0444] Furthermore, if the first wheel 102 is, for example, an omnidirectional wheel 1, the wheel member 4 may be attached to an axle 102b rotatably supported on the vehicle body 101 as shown in FIG. 37 without providing a hub 2 and a bearing 3.

[0445] Hereinafter, the description will be given on the assumption that the rotation axis of the first wheel 102 in the fourth embodiment is the axle 102b.

[0446] For example, when the drive unit 105 (HST107L, 107R) functions as the first vehicle body turning device S1 and the vehicle body 101 makes a pivot turn or an ultra-pivot turn, the left and right first wheels 102 remain in contact with the ground and move as the vehicle body 101 turns without rotating left or right relative to the vehicle body 101.

[0447] Here, since the first wheel 102 is an omnidirectional wheel W, the turning direction of the vehicle body 101 (turning direction T shown in FIG. 18 ) coincides with the rotation direction (roller rotation direction Cr) of the roller in contact with the ground (roller 40 of the omnidirectional wheel 50, or the first roller 6 or second roller 7 of the omnidirectional wheel 1). Therefore, the roller in contact with the ground (roller 40, or the first roller 6 or second roller 7) rotates, and the first wheel 102 does not skid (slide with friction) on the ground.

[0448] 37 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.

[0449] 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.

[0450] 37 , 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 traction motor 109, which is linked to the axle 103 a 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 102 b of the first wheel (front wheel) 102.

[0451] However, the 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 transmission mechanism 140 is not limited to one that uses a transmission shaft 141 with a universal joint and a bevel gear mechanism as shown in Fig. 21, and 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.

[0452] 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.

[0453] However, in the work vehicle 100 of Figure 37, the drive unit 105 functions as the first body turning device S1 to turn the body 101, so it is necessary to ensure a difference in rotational speed and / or rotational direction between the left and right second wheels 103 (left rear wheel 103L and right rear wheel 103R) during the turn.

[0454] To achieve this, it is necessary to make the axles 102b of the left and right first wheels 102 (left front wheel 102L and right front wheel 102R) independent from each other so that the rotation (changes in rotation speed and rotation direction) of the first wheel 102 and the second wheel 103 on the same left and right sides of the vehicle body 101 (left front wheel 102L and left rear wheel 103L, and right front wheel 102R and right rear wheel 103R) can be synchronized.

[0455] For this reason, in the work vehicle 100 of Fig. 37, 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, in the work vehicle 100 of Fig. 21, two separate transmission shafts 141 are provided, and each transmission shaft 141 interconnects the first wheel 102 and second wheel 103 (travel motors 109 interconnected to them) on the same left or right side of the vehicle body 101.

[0456] 37 is capable of switching its travel mode between a four-wheel drive mode and a two-wheel drive mode. To this end, in each transmission mechanism 140, a clutch 142 is provided between the transmission shaft 141 and the axle 102b of the first wheel 102.

[0457] 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).

[0458] The clutch 142 is a hydraulic clutch that is turned on and off by a hydraulic actuator 143 such as a piston that is hydraulically operated. 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.

[0459] When the work vehicle 100 is being driven by a person, the worker operates a driving mode selection switch or the like included in the input device 131, and the control device 110 reads the signal from the switch or the like and controls the control valve for controlling the hydraulic actuator 143.

[0460] The clutch 142 is not limited to a hydraulic clutch, but 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.

[0461] [Work vehicle according to fifth embodiment] In the third and fourth embodiments described above, a tractor has been used as an example of a work vehicle equipped with omnidirectional wheels 1, but omnidirectional wheels W may also be provided on work vehicles other than tractors. Figure 38 is a perspective view of a work vehicle (rover) 200 according to a fifth embodiment equipped with omnidirectional wheels 1. The work vehicle 200 is, for example, an unmanned exploration vehicle (rover).

[0462] 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 W via vertical pivot shafts 203 and axle cases 204 at four locations on the traveling frame (vehicle body) 202: the left front end, right front end, left rear end, and right rear end. In other words, the work vehicle 200 is equipped with four omnidirectional wheels W.

[0463] It should be noted that the omnidirectional wheel W shown in FIG. 38 has the appearance of the omnidirectional wheel 1 shown in FIGS. 17 to 33, but this does not mean that the omnidirectional wheel W shown in FIG. 38 is limited to the omnidirectional wheel 1, and may be replaced with, for example, an omnidirectional wheel 50 having the appearance shown in FIGS. 1 to 16.

[0464] All four omnidirectional wheels W of the work vehicle 200 are drive wheels. Each omnidirectional wheel W 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 W of the work vehicle 100, and the second wheel 103, which is the drive wheel.

[0465] These axle drive motors 205 are housed in the respective axle cases 204 and rotate the omnidirectional wheels W. That is, in the fifth embodiment, the wheel members of the omnidirectional wheels W (the wheel members 20 of the omnidirectional wheels 50 or the wheel members 4 of the omnidirectional wheels 1) are attached to the drive shafts 205a of the axle drive motors 205. That is, the rotation shaft of the omnidirectional wheels W in the fifth 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 wheels W.

[0466] 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.

[0467] 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 (car body) 202 by varying the rotation speed and / or rotation direction between the omnidirectional wheel W supported on the left side of the traveling frame (car body) 202 and the omnidirectional wheel W supported on the right side of the traveling frame (car body) 202.

[0468] Each omnidirectional wheel W can rotate horizontally (left and right) together with its axle case 204 around the rotation shaft 203. That is, each omnidirectional wheel W 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 W around the rotation shaft 203, the steering actuator or the like can function as the second body turning device S2.

[0469] When the multiple axle drive motors 205 function as the first body turning device S1 to change the rotational speed and / or rotation direction of the left and right omnidirectional wheels W to turn the running frame (body) 202, or when the steering actuator functions as the second body turning device S2 to turn the omnidirectional wheel 1 as a steering wheel left and right, the roller that is in contact with the ground among the multiple rollers of the omnidirectional wheel W (roller 40 of omnidirectional wheel 50, or rollers 6, 7 of omnidirectional wheel 1) rotates 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.

[0470] 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 W, can be provided as a rover with such high traction capability.

[0471] 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 W. Alternatively, the work vehicle 200 may be provided with a device that switches the stopper (60 of the omnidirectional wheel 50 or the stopper 10 of the omnidirectional wheel 1) provided on each omnidirectional wheel W between a stopper release position (stopper release position) P1 and a stopper activation position (stopper activation position) P2, and the omnidirectional wheel W may be configured to act as a unidirectional wheel only at that time by switching the stopper (stopper 60 or stopper 10) to the stopper activation position (stopper activation position) P2.

[0472] The functions and effects of each configuration of the omnidirectional wheel 50 and the work vehicles 100, 200 equipped with the omnidirectional wheel 50 described above will be described below.

[0473] The configuration, actions, and effects described below also include matters that are common to the omnidirectional wheel 1 and the work vehicles 100 and 200 equipped with the omnidirectional wheel 1 .

[0474] (Item A1) An omnidirectional wheel (50) comprising: a wheel member (20); and a roller (40) rotatably supported along an outer periphery (21) of the wheel member (20) in a second rotation direction (Cr) that intersects with a first rotation direction (Cw) that is a rotation direction of the wheel member (20), wherein the roller (40) has a protrusion (45) that protrudes from the outer periphery of the roller (40) so as to resist rotation of the roller (40) in the second rotation direction (Cr).

[0475] As a result, the rollers 40 rotate in the second rotation direction Cr, providing the characteristics of an omnidirectional wheel with good turning ability without skidding, while the protruding portions 45 that protrude to resist the rotation of the rollers 40 come into contact with the ground and provide good grip on the soil, etc., thereby ensuring ease of escaping from a stuck state, which is required in agricultural fields, etc., and making it possible to provide an omnidirectional wheel 50 suitable for use on agricultural work vehicles, etc.

[0476] (Item A2) The omnidirectional wheel 50 according to Item A1, wherein the roller 40 has a plurality of the protrusions 45, the plurality of protrusions 45 protruding radially from the outer periphery of the roller 40 around an axis Xr of the roller 40 and arranged in the second rotation direction Cr.

[0477] This allows the above-described characteristics of the protrusion 45 to be exhibited regardless of the rotational position in the second rotational direction Cr at which the roller 40 of the omnidirectional wheel 50 comes into contact with the ground.

[0478] (Item A3) The omnidirectional wheel 50 according to Item A1 or A2, wherein the roller 40 has a shape in which the diameter Dr changes as the roller 40 moves in the axial direction Xr, and the protrusion 45 protrudes from at least a portion of the outer periphery of the roller 40 where the diameter Dr is maximum.

[0479] This further increases the diameter from the axis Xr of the roller 40 to the top of the protrusion 45, improving the grip of the protrusion 45 on the soil, etc., and making it easier for the omnidirectional wheel 50 to escape from a stuck state.

[0480] (Item A4) The omnidirectional wheel 50 according to Item A3, wherein the roller 40 has a first end 40a and a second end 40b that face each other in an axial direction Xr of the roller 40, the diameter Dr of the first end 40a is larger than the diameter Dr of the second end 40b, and the protrusion 45 protrudes beyond an outer periphery of at least the first end 40a of the first end 40a and the second end 40b.

[0481] This allows the protrusions 45 to optimally grip the soil, etc., in an omnidirectional wheel 50 having rollers 40 with a shape (e.g., cup-shaped) in which the diameter of the first end 40a is larger than that of the second end 40b.

[0482] (Item A5) The omnidirectional wheel 50 according to Item A4, wherein the roller 40 has a shape in which the diameter Dr gradually decreases as the roller 40 moves from the first end 40a to the second end 40b in the axial direction Xr.

[0483] This allows the omnidirectional wheel 50, which has a roller 40 that has a tapered (e.g., cup-shaped) shape from the first end 40a to the second end 40b, to optimally grip the soil, etc., with the protrusion 45.

[0484] (Item A6) The omnidirectional wheel 50 according to any one of Items A1 to A5, wherein a plurality of the rollers 40 are arranged in the first rotation direction Cw along the outer circumferential portion 21 of the wheel member 20.

[0485] This allows the above-described properties of the protrusion 45 to be exhibited regardless of which of the rollers 40 of the omnidirectional wheel 50 is in contact with the ground.

[0486] (Item A7) The omnidirectional wheel 50 according to Item A6, further comprising a bracket 30 attached to the outer circumferential portion 21 of the wheel member 20 and supporting at least two rollers 40 of the plurality of rollers 40, wherein the at least two rollers 40 supported by the bracket 30 include a first roller 40A arranged on one side of the bracket 30 in the first rotation direction Cw and a second roller 40B arranged on the other side of the bracket 30.

[0487] This allows one bracket 30 to support at least two rollers 40, including a first roller 40A on one side and a second roller 40B on the other side, thereby reducing the number of parts required to support all rollers 40 arranged in the first rotation direction Cw on the omnidirectional wheel 50 on the outer periphery 21 of the wheel member 20, and contributing to cost reduction.

[0488] (Item A8) The omnidirectional wheel 50 according to Item A7, wherein the bracket 30 has a roller insertion recess 32 a that opens on the one side in the first rotation direction Cw and a protrusion 32 b that protrudes on the other side, and each of the plurality of rollers 40 has a first end 40 a on the one side, a second end 40 b on the other side, and a bracket insertion recess 40 c that opens at the first end 40 a, and the second end 40 b of the first roller 40A is inserted into the roller insertion recess 32 a of the bracket 30, and the protrusion 32 b of the bracket 30 is inserted into the bracket insertion recess 40 c of the second roller 40B.

[0489] As a result, the convex portion 32b of the bracket 30 is positioned within the bracket insertion recess 40c of the second roller 40B, and the second end 40b of the first roller 40A inserted into the roller insertion recess 32a of the bracket 30 is also positioned within the bracket insertion recess 40c of the second roller 40B. In other words, the first roller 40A and the second roller 40B are supported by the bracket 30 with the second end 40b of the first roller 40A inserted into the bracket insertion recess 40c on the side of the first end 40a of the second roller 40B. In this way, the multiple rollers 40 are well-arranged without gaps in the first rotation direction Cw, and each roller 40 is reliably supported by the bracket 30 so that the rollers 40 do not interfere with each other in the second rotation direction Cr.

[0490] (Item A9) The omnidirectional wheel 50 according to Item A1 or A2, further comprising: brackets 30 attached to the outer circumferential portion 21 of the wheel member 20 and supporting the rollers 40, a plurality of the brackets 30 being arranged along the outer circumferential portion 21 of the wheel member 20 in the first rotation direction Cw, the plurality of brackets 30 including a first bracket 30A supporting the rollers 40 on one side in the first rotation direction Cw and a second bracket 30B supporting the rollers 40 on the other side.

[0491] As a result, the roller 40 is supported on one side by the first bracket 30A and on the other side by the second bracket 30B in the first rotation direction Cw, and can therefore rotate in the second rotation direction Cr in a stable state.

[0492] (Item A10) The omnidirectional wheel 50 according to Item A9, wherein the protrusion 45 has a first side surface 45c1 facing the one side, a second side surface 45c2 facing the other side, and an apex surface 45a extending between the first side surface 45c1 and the second side surface 45c2 at an apex in a radial direction from the axis Xr of the roller 40, and when the protrusion 45 reaches a position where the apex surface 45a faces the wheel member 20 in the gap between the first bracket 30A and the second bracket 30B due to rotation of the roller 40 in the second rotation direction Cr, the first side surface 45c1 faces the first bracket 30A and the second side surface 45c2 faces the second bracket 30B.

[0493] As a result, the protrusion 45, which moves forward and backward relative to the wheel member 20 as the roller 40 rotates in the second rotation direction Cr, can penetrate into the gap between the first bracket 30A and the second bracket 30B when approaching the wheel member 20, and can reach the limit of the position at which it can approach the wheel member 20.This ensures that the diameter length from the axis Xr of the roller 40 to the apex (apex surface 45a) of the protrusion 45 is at its maximum, improving the grip of the protrusion 45 on soil, etc., and making it easier for the omnidirectional wheel 50 to escape from a stuck state.

[0494] (Item A11) A work vehicle 100 including the omnidirectional wheel 50 according to Item A1 or A2, an axle 157 connected to the wheel member 20 of the omnidirectional wheel 50, and a vehicle body 101 that rotatably supports the axle 157.

[0495] As a result, the rollers 40 rotate in the second rotation direction Cr, giving the omnidirectional wheel the characteristics of good turning ability without skidding, but the protruding portions 45 that protrude to resist the rotation of the rollers 40 come into contact with the ground and provide good grip on the soil, etc., so that the omnidirectional wheels 50 also ensure ease of escaping from a stuck state, which is required in agricultural fields, etc., and a work vehicle 100 that is highly useful as a work vehicle for agricultural use, etc., can be provided.

[0496] (Item B1) An omnidirectional wheel 50 comprising: a wheel member 20 having a cylindrical outer circumferential portion 21 extending in an axial direction; a bracket 30 attached to the outer circumferential portion 21 of the wheel member 20; and a roller 40 supported by the bracket 30 so as to be rotatable in a second rotation direction Cr that intersects with a first rotation direction Cw that is a rotation direction of the wheel member 20, wherein the outer circumferential portion 21 of the wheel member 20 is provided with a contact portion 24 that comes into contact with the bracket 30 attached to the wheel member 20 and extends in the axial direction Xw of the wheel member 20, and at least one part of the contact portion 24 that is positioned differently in the axial direction Xw is positioned differently in the radial direction of the wheel member 20.

[0497] As a result, simply by attaching the bracket 30 supporting the roller 40 to the outer periphery 21 of the wheel member 20 in a state in contact with the contact portion 24, it is possible to prevent the bracket 30 from shifting in position relative to the wheel member 20 in the axial direction Xw, thereby improving the ease of assembly of the omnidirectional wheel 50 and contributing to a reduction in the manufacturing cost of the omnidirectional wheel 50, and also making it possible to provide an omnidirectional wheel 50 with a stable structure that does not allow such shifting to occur.

[0498] (Item B2) The omnidirectional wheel 50 according to Item B1, wherein the wheel member 20 has a groove 23 formed in the outer circumferential portion 21, the groove 23 extending in the axial direction Xw, the bracket 30 is fitted into the groove 23 to be attached to the wheel member 20, and the contact portion 24 is a bottom end surface of the groove 23 in the radial direction.

[0499] This allows the bracket 30 to be in contact with the contact portion 24 as described above simply by fitting the bracket 30 into the groove 23, further improving the ease of assembly of the omnidirectional wheel 50.

[0500] (Item B3) The omnidirectional wheel 50 according to Item B1 or B2, wherein a portion of the outer circumferential portion 21 of the wheel member 20 other than the contact portion 24 is a curved plate portion 22 that is bent so that a diameter Dw changes as the portion moves in the axial direction Xw, and the contact portion 24 is bent along the curved plate portion 22.

[0501] As a result, by simply providing the contact portion 24 in a bent state along the curved plate portion 22 on the wheel member 20 having a curved shape derived from the curved plate portion 22, it is possible to provide a wheel member 20 having a contact portion 24 that can prevent the bracket 30 from shifting out of position relative to the wheel member 20, as described above, thereby improving the simplicity and ease of processing of the wheel member 20.

[0502] (Item B4) The omnidirectional wheel 50 according to Item B3, wherein the wheel member 20 has, in the axial direction Xw, an inner end 25 that is closer to the vehicle when attached to the vehicle and an outer end 26 that is farther from the vehicle, and the curved plate portion 22 has different diameters Dw1, Dw2 at the inner end 25 and the outer end 26.

[0503] This allows for the provision of an omnidirectional wheel 50 with a structure adapted to situations where, when mounted on a vehicle, it is desirable for the wheel to have different diameters at its inner and outer ends to correspond to the structure of the vehicle adjacent to the wheel.

[0504] (Item B5) The omnidirectional wheel 50 according to Item B4, wherein a diameter Dw1 at the inner end 25 of the curved plate portion 22 is larger than a diameter Dw2 at the outer end 26 of the curved plate portion 22.

[0505] This makes it possible, for example, to insert a steering shaft case 152b or the like, which functions as a steering shaft to be arranged inside the wheel, into the inner bore 28 of the wheel member 20, which opens at the inner end 25 having a large diameter Dw1, and connect the axle 157 protruding from the steering shaft case 152b to the wheel member 20, thereby increasing the adaptability of the omnidirectional wheel 50 when it is attached to a work vehicle as a steering wheel, etc.

[0506] (Item B6) The omnidirectional wheel 50 according to Item B5, wherein the diameter Dw of the curved plate portion 22 increases as it moves from the outer end 26 to the inner end 25 in the axial direction Xw.

[0507] As a result, when the omnidirectional wheel 50 is attached to a vehicle as described above, the steering axle case 152b is positioned within the inner cavity 28 surrounded by the outer periphery 21 of the wheel member 20, and the roller 40 is positioned outside the outer periphery 21 of the wheel member 20. In this situation, the wheel member 20 (its outer periphery 21), which has a shape whose diameter Dw increases as it moves from the outer end 26 to the inner end 25, is positioned appropriately in the gap between the steering axle case 152b and the roller 40, thereby further increasing the adaptability of the omnidirectional wheel 50 when it is attached to a work vehicle as a steering wheel as described above.

[0508] (Item B7) The omnidirectional wheel 50 according to any one of Items B4 to B6, wherein a diameter ratio between the outer end 26 and the inner end 25 of the wheel member 20 is set corresponding to a camber angle θ1 of the omnidirectional wheel 1 that corresponds to a depression angle θ1 of the axis Xw of the wheel member 20.

[0509] This further enhances the adaptability of the omnidirectional wheel 50, even assuming a case where the omnidirectional wheel 50 is attached to a vehicle with a camber angle θ1 appropriate for the wheel of the vehicle.

[0510] (Item B8) The omnidirectional wheel 50 according to any one of Items B4 to B7, wherein the roller 40 has a protruding portion 45 that protrudes from an outer periphery of the roller 40, the wheel member 20 is connected to an axle 157 of a work vehicle 100, and the curvature of the curved plate portion 22 of the wheel member 20 is set so that a portion including at least the inner end 25 of the curved plate portion 22 is positioned between the protruding portion 45 and an axle case 152 (steering shaft case 152 b) that houses the axle 157, regardless of rotation of the roller 40 in the second rotation direction Cr.

[0511] As a result, when the omnidirectional wheel 50 is attached to a vehicle as described above, the steering axle case 152b is positioned within the inner cavity 28 surrounded by the outer periphery 21 of the wheel member 20, and the roller 40 having the protrusion 45 is positioned outside the outer periphery 21 of the wheel member 20. In this situation, the wheel member 20 (its outer periphery 21), which has a shape whose diameter Dw increases as it moves from the outer end 26 to the inner end 25, is positioned appropriately in the gap between the steering axle case 152b and the protrusion 45 of the roller 40, thereby further increasing the adaptability of the omnidirectional wheel 50 when it is attached to a work vehicle as a steering wheel as described above.

[0512] (Item B9) A work vehicle 100 including an omnidirectional wheel 50 according to any one of Items B1 to B8, an axle 157 connected to the wheel member 20 of the omnidirectional wheel 50, and a vehicle body 101 that rotatably supports the axle 157.

[0513] This improves ease of assembly, resulting in lower costs, and makes it possible to provide a work vehicle 100 equipped with omnidirectional wheels 50 having a stable structure that prevents misalignment of the bracket 30 relative to the wheel member 20 in the axial direction Xw.

[0514] (Item C1) An omnidirectional wheel 50 comprising: a wheel member 20; and a plurality of rollers 40 rotatably supported along an outer circumferential portion 21 of the wheel member 20 in a second rotation direction Cr that intersects with a first rotation direction Cw, which is a rotation direction of the wheel member 20, wherein each of the plurality of rollers 40 has a roller axle 41 that is disposed along the first rotation direction Cw and serves as a center of rotation of the roller 40 in the second rotation direction Cr, and a cylindrical body 42 that is provided around the roller axle 41, and the plurality of rollers 40 includes at least one combined roller 40H, and the cylindrical body 42 of the combined roller 40H is formed by combining a first member 42A having a ground contact portion 45 a and a second member 42B having the ground contact portion 45 a.

[0515] As a result, during the manufacturing process of the omnidirectional wheel 50, while the plurality of rollers 40 are arranged in a row along the first rotation direction Cw, the main body 42 of the combined roller 40H is disassembled into the first member 42A and the second member 42B and assembled into the row, and then the first member 42A and the second member 42B are assembled to complete the main body 42 with the ground contact portion 45a (the top end surfaces 45a of the lugs 45), simplifying the process of assembling the row of the plurality of rollers 40 along the outer circumferential portion 21 of the wheel member 20. In this way, the omnidirectional wheel 50 has a configuration that improves the ease of assembly of the plurality of rollers 40, including the combined roller 40H.

[0516] (Item C2) The omnidirectional wheel 50 according to Item C1, wherein in the combined roller 40H, the ground contact portion 45a of the first member 42A and the ground contact portion 45a of the second member 42B are connected in the second rotation direction Cr.

[0517] As a result, during the manufacturing process of the omnidirectional wheel 50, by combining the first member 42A and the second member 42B as described above to complete the main body 42, it is possible to complete the row of multiple ground contact portions 45a on the main body 42 of the roller 40H. In this way, the omnidirectional wheel 50 has a configuration that is improved not only in terms of ease of assembly of multiple rollers 40 including the combined roller 40H, but also in terms of ease of assembly of the combined roller 40H with the ground contact portions 45a.

[0518] (Item C3) The omnidirectional wheel 50 according to Item C1 or C2, wherein the roller shaft 41 of the combined roller 40H includes a first shaft member 41c and a second shaft member 41d that are separate and arranged on the same axis.

[0519] As a result, when the main body 42 of the combined roller 40H is disassembled into the first member 42A and the second member 42B as described above and the shaft hole 40d is exposed, the space created by the disassembly can be used to easily insert the first shaft member 41c and the second shaft member 41d, which are shorter than the entire length of the roller shaft 41, into the shaft hole 40d, and then the first member 42A and the second member 42B can be combined to complete the main body 42 with the first shaft member 41c and the second shaft member 41d as the roller shaft 41. In this way, the omnidirectional wheel 50 has a configuration that improves the ease of assembly of the combined roller 40H with the roller shaft 41, in addition to the ease of assembly of multiple rollers 40 including the combined roller 40H.

[0520] (Item C4) The omnidirectional wheel 50 according to Item C3, wherein the roller shaft 41 of each of the plurality of rollers 40 has a first end 41 a and a second end 41 b that face each other in the axial direction Xr, and a tip of the first shaft member 41 c is the first end 41 a of the roller shaft 41 of the combined roller 40H, and a tip of the second shaft member 41 d is the second end 41 b of the roller shaft 41 of the combined roller 40H.

[0521] As a result, the first shaft member 41c and the second shaft member 41d incorporated in the combined roller 40H function as the first end 41a and the second end 41b of the roller shaft 41 of each of the plurality of rollers 40 including the combined roller 40H. Therefore, the combined roller 40H is configured to be supported at both ends, at the first end 41a and the second end 41b of the roller shaft 41, like the rollers 40 other than the combined roller 40H.

[0522] (Item C5) The omnidirectional wheel 50 according to Item C4, comprising a plurality of brackets 30 attached to the outer circumferential portion 21 of the wheel member 20 and arranged in the first rotational direction Cw, wherein each of the plurality of brackets 30 has a first shaft support recess 32 c that opens to the one side in the first rotational direction Cw and a second shaft support recess 32 d that opens to the other side, the plurality of brackets 30 including a first bracket 30H1 that supports the combined roller 40H on the one side in the first rotational direction Cw and a second bracket 30H2 that supports the combined roller 40H on the other side in the first rotational direction Cw, the first shaft member 41 c being inserted into the second shaft support recess 32 d of the first bracket 30H1, and the second shaft member 41 d being inserted into the first shaft support recess 32 c of the second bracket 30H2.

[0523] As a result, when the main body 42 of the combined roller 40H is disassembled into the first member 42A and the second member 42B as described above and the shaft hole 40d is exposed, the first shaft member 41c and the second shaft member 41d, which are shorter than the full length of the roller shaft 41, can be easily inserted into the shaft hole 40d using the space created by the disassembly. When the first shaft member 41c and the second shaft member 41d are fitted into the shaft hole 40d, the first shaft member 41c is inserted into the second shaft support recess 32d of the first bracket 30H1, and the second shaft member 41d is inserted into the first shaft support recess 32c of the second bracket 30H2, so that the main body 42 of the disassembled combined roller 40H is supported at both ends by the first bracket 30H1 and the second bracket 30H2. Then, by combining the first member 42A and the second member 42B, the main body 42 can be completed with the first shaft member 41c and the second shaft member 41d as the roller shafts 41. In this way, the omnidirectional wheel 50 has a configuration that improves not only the ease of assembly of multiple rollers 40, including the combined roller 40H, but also the ease of assembly of the combined roller 40H with the roller shafts 41 that are supported at both ends by the two brackets 30 (30H1, 30H2).

[0524] (Item C6) A work vehicle 100 including an omnidirectional wheel 50 according to any one of Items C1 to C5, an axle 157 connected to the wheel member 20 of the omnidirectional wheel 50, and a vehicle body 101 that rotatably supports the axle 157.

[0525] This makes it possible to provide a work vehicle 100 equipped with omnidirectional wheels 50 having a configuration that is improved in terms of ease of assembly of multiple rollers 40, including the combined roller 40H.

[0526] (Item C7) A method for manufacturing the omnidirectional wheel 50 according to any one of Items C1 to C4, the method comprising: a roller arranging step of arranging one roller 40 along the outer circumferential portion 21 of the wheel member 20, and then sequentially arranging other rollers 40 on one end side of the roller 40 in the axial direction Xr to form a row of the plurality of rollers 40 in the first rotation direction Cw, and finally assembling the combined roller 40H into the row with the main body 42 missing at least one of the first member 42A and the second member 42B; and a combined roller completing step of, after the roller arranging step, adding the missing first member 42A and / or the missing second member 42B to complete the main body 42 of the combined roller 40H.

[0527] As a result, in the roller arranging process for forming a row of multiple rollers 40 along the first rotation direction Cw, at the stage of assembling the combined roller 40H into the row last, the main body 42 can be disassembled into the first member 42A and the second member 42B and assembled into the row, and then the first member 42A and the second member 42B can be assembled into the row in the combined roller completing process to complete the main body 42 with the ground contact portion 45a, facilitating the process of sequentially arranging the multiple rollers 40 along the outer circumferential portion 21 of the wheel member 20 to complete the row of rollers 40. In this way, it is possible to provide a manufacturing method for an omnidirectional wheel 50 that is improved in terms of ease of assembly of multiple rollers 40, including the combined roller 40H.

[0528] (Item C8) A method of manufacturing the omnidirectional wheel 50 according to Item C5, further comprising: a roller arranging step of arranging one roller 40 along the outer circumferential portion 21 of the wheel member 20, and then sequentially arranging other rollers 40 on one end side of the roller 40 in the axial direction Xr to form a row of the plurality of rollers 40 in the first rotation direction Cw, and finally incorporating the combined roller 40H into the row in a state in which the main body 42 is missing at least one of the first member 42A and the second member 42B; and a method of manufacturing the omnidirectional wheel 50 according to Item C5, further comprising: a roller arranging step of arranging the first axial member 41 after the roller arranging step; a roller shaft assembling step of inserting the first member 42A and the second member 42B into the second shaft support recess 32d of the first bracket 30H1 and assembling the combined roller 40H, and inserting the second shaft member 41d into the first shaft support recess 32c of the second bracket 30H2 and assembling the combined roller 40H; and a combined roller completing step of, after the roller shaft assembling step, filling in the missing first member 42A and / or the second member 42B to complete the main body 42 of the combined roller 40H.

[0529] As a result, during the roller arrangement process in which a row of multiple rollers 40 is formed along the first rotation direction Cw, in order to finally incorporate the combined roller 40H into the row, the main body 42 is disassembled into the first member 42A and the second member 42B and then assembled into the row. With the shaft hole 40d exposed, the space created by the disassembly can be used to carry out the roller shaft assembly process, and the first shaft member 41c and the second shaft member 41d, which are shorter than the full length of the roller shaft 41, can be easily inserted into the shaft hole 40d. When the first shaft member 41c and the second shaft member 41d are fitted into the shaft hole 40d, the first shaft member 41c is inserted into the second shaft support recess 32d of the first bracket 30H1, and the second shaft member 41d is inserted into the first shaft support recess 32c of the second bracket 30H2, so that the main body 42 of the disassembled combined roller 40H is supported at both ends by the first bracket 30H1 and the second bracket 30H2. Subsequently, the combined roller completion process is performed to combine the first member 42A and the second member 42B, thereby completing the main body 42 with the first shaft member 41c and the second shaft member 41d as the roller shafts 41. In this way, a manufacturing method for an omnidirectional wheel 50 can be provided that is improved in terms of ease of assembly of multiple rollers 40, including the combined roller 40H, as well as ease of assembly of the combined roller 40H with the roller shafts 41 supported at both ends by the two brackets 30 (30H1, 30H2).

[0530] 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.

[0531] DESCRIPTION OF SYMBOLS 20: Wheel member 21: Outer periphery 22: Curved plate portion 23: Groove 24: Contact portion (bottom end surface of groove) 25: Inner end surface 26: Outer end surface 30: Bracket 30A: First bracket 30B: Second bracket 30H1: First bracket 30H2: Second bracket 31: Support plate portion 31a: Base end portion 32: Bent portion 32a: Roller insertion recess 32b: Convex portion 32c: First shaft support recess (through hole) 32d: Second shaft support recess 33: Stop plate 40: Roller 40A: First roller 40B: Second roller 40H: Combined roller 40a: First end portion 40b: Second end portion 40c: Bracket insertion recess 40d: Shaft hole 41 : Roller shaft 41a : First end 41b : Second end 41c : First shaft member 41d : Second shaft member 41e : Spacer shaft 42 : Main body 42A : First member 42B : Second member 45 : Lug (protruding portion) 45a : Top end surface (ground contact portion) 45b : Side surface along axis 45c : Side surface along outer periphery 45c1 : First side 45c2 : Second side 50 : Omnidirectional wheel 60 : Stopper 61 : Retaining plate 62 : Boss member 100 : Work vehicle (tractor) 101 : Body 152 : Axle case 157 : Axle 200 : Work vehicle (rover) 202 : Body (traveling frame) Cr : Roller rotation direction Cw : Wheel rotation direction θ1 : Camber angle (depression angle) Dw : ​​Roller diameter Dw1 : Inner end diameter Dw2 : Outer end diameter

Claims

1. An omnidirectional wheel comprising: a wheel member; and a roller supported along the outer periphery of the wheel member so as to be rotatable in a second rotational direction that intersects a first rotational direction that is the rotational direction of the wheel member, wherein the roller has a protrusion that protrudes from the outer periphery of the roller so as to resist rotation of the roller in the second rotational direction.

2. The omnidirectional wheel according to claim 1, wherein the roller has a plurality of protrusions, the plurality of protrusions protruding radially from the outer periphery of the roller with the axis of the roller as the center and arranged in the second rotation direction.

3. An omnidirectional wheel according to claim 1 or 2, wherein the roller has a shape whose diameter changes as it moves in the axial direction of the roller, and the protrusion protrudes from at least the part of the outer periphery of the roller where the diameter is greatest.

4. An omnidirectional wheel according to claim 3, wherein the roller has a first end and a second end that face each other in the axial direction of the roller, the diameter of the first end is larger than the diameter of the second end, and the protrusion protrudes beyond the outer periphery of at least the first end of the first and second ends.

5. The omni-directional wheel of claim 4, wherein the rollers have a shape that gradually reduces in diameter as they transition axially from the first end to the second end.

6. The omnidirectional wheel according to claim 1 or 2, wherein a plurality of the rollers are arranged along the outer periphery of the wheel member in the first rotation direction.

7. The omnidirectional wheel according to claim 6, further comprising a bracket attached to the outer periphery of the wheel member and supporting at least two of the plurality of rollers, wherein the at least two rollers supported by the bracket include a first roller disposed on one side of the bracket in the first rotational direction, and a second roller disposed on the other side of the bracket.

8. An omnidirectional wheel as set forth in claim 7, wherein the bracket has a roller insertion recess that opens on the one side in the first rotation direction and a protrusion that protrudes on the other side, and each of the plurality of rollers has a first end on the one side, a second end on the other side, and a bracket insertion recess that opens at the first end, the second end of the first roller is inserted into the roller insertion recess of the bracket, and the protrusion of the bracket is inserted into the bracket insertion recess of the second roller.

9. The omnidirectional wheel according to claim 1 or 2, further comprising brackets attached to the outer periphery of the wheel member and supporting the rollers, a plurality of the brackets being arranged along the outer periphery of the wheel member in the first rotational direction, and the plurality of brackets including a first bracket supporting the rollers on one side and a second bracket supporting the rollers on the other side in the first rotational direction.

10. An omnidirectional wheel according to claim 9, wherein the protrusion has a first side surface facing the one side, a second side surface facing the other side, and an apex surface extending between the first side surface and the second side surface at an apex in a radial direction from the axis of the roller, and when the protrusion reaches a position where the apex surface faces the wheel member in the gap between the first bracket and the second bracket due to rotation of the roller in the second rotational direction, the first side surface faces the first bracket and the second side surface faces the second bracket.

11. A work vehicle comprising: an omnidirectional wheel according to claim 1 or 2; an axle connected to the wheel member of the omnidirectional wheel; and a vehicle body that rotatably supports the axle.

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