Driving wheel and bogie

Abstract

To provide a driving wheel and a bogie allowing stable traveling as suppressing yawing while being provided with a differential type all-direction movement mechanism.SOLUTION: A driving wheel 110 includes: a first input shaft 25A and a second input shaft 25B on the same axis; an axle 37 provided to intersect to the first input shaft 25A; a first wheel 15A and a second wheel 15B provided on the axle 37; a rotation shaft 35 rotatably provided on the same axis as the first input shaft 25A and the second input shaft 25B to revolvably support each of wheels 15A, 15B through the axle 37; a first rotational force transmission mechanism 13A transmitting rotational force of the first input shaft 25A to the first wheel 15A; and a second rotational force transmission mechanism 13B transmitting rotational force to the first wheel 15A with a rotation reversed to that of the first input shaft 25A of the second input shaft 25B at the same speed and to the second wheel 15B with the same rotation at the same speed.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a drive wheel and a carriage.

Background Art

[0002] Patent Document 1 shows a differential-type wheel drive device (drive wheel). This wheel drive device has two drive units and two wheels, and transmits the rotational force of one drive unit to one wheel and the rotational force of the other drive unit to the other wheel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the drive wheel described in Patent Document 1, in its embodiment, when the rotations of two input shafts connected to the wheels through a turning axis are the same, it is a combination for performing pure forward and backward movement. However, this combination is configured to transmit the rotational force from each input shaft extending vertically due to the meshing of bevel gears to each axle extending horizontally, and since the rotational directions of the two input shafts are the same, there is a movement (yawing) that sways left and right with respect to forward and backward movement, and this generates a force that rotates the turning axis. For this reason, conventionally, for example, there is a concern that when an external force that causes turning is applied during straight travel, the running becomes unstable.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a drive wheel and a carriage that can perform stable running while suppressing yawing while including a differential-type omnidirectional movement mechanism.

Means for Solving the Problems

[0006] To achieve the above object, a drive wheel according to an aspect of the present disclosure includes a first input shaft and a second input shaft on the same axis, an axle provided to intersect the first input shaft, a first wheel and a second wheel provided on the axle, a swivel shaft rotatably provided coaxially with the first input shaft and the second input shaft and supporting each of the wheels via the axle so as to be swiveling, a first rotational force transmission mechanism for transmitting the rotational force of the first input shaft to the first wheel, and a second rotational force transmission mechanism for transmitting a rotational force that rotates in the opposite direction to the first input shaft and has the same speed as the first input shaft to the second wheel in the same direction and at the same rotational speed as the first wheel.

[0007] As a desirable aspect of the above drive wheel, the first rotational force transmission mechanism is composed of a first conversion gear and a first conversion output gear provided on axes orthogonal to each other, and the second rotational force transmission mechanism is composed of a second conversion gear and a second conversion output gear provided on axes orthogonal to each other, and the first conversion gear, the first conversion output gear, the second conversion gear, and the second conversion output gear are bevel gears.

[0008] As a desirable aspect of the above drive wheel, it further includes an output shaft provided to intersect the first input shaft and the second input shaft, the first rotational force transmission mechanism transmits the rotational force of the first input shaft to the first wheel as rotation around the output shaft, and the second rotational force transmission mechanism transmits the rotational force of the second input shaft to the second wheel as rotation around the output shaft.

[0009] As a desirable aspect of the above drive wheel, it further includes an intersecting output shaft provided to intersect the first input shaft and parallel to the axle, and a parallel output shaft provided parallel to the second input shaft and intersecting the axle, the first rotational force transmission mechanism transmits the rotational force of the first input shaft to the first wheel as rotation around the intersecting output shaft, and the second rotational force transmission mechanism transmits the rotational force of the second input shaft to the second wheel as rotation around the parallel output shaft.

[0010] As a desirable aspect of the drive wheels, the drive wheels further include a first parallel output shaft provided parallel to the first input shaft on a shaft different from the first input shaft, and a second parallel output shaft provided parallel to the second input shaft on a shaft different from the second input shaft. The first rotational force transmission mechanism transmits the rotational force of the first input shaft to the first wheel via the first parallel output shaft, and the second rotational force transmission mechanism transmits the rotational force of the second input shaft to the second wheel via the second parallel output shaft.

[0011] As a desirable aspect of the drive wheels, the rotational axis centers of the respective wheels are displaced and arranged in a horizontal direction orthogonal to the axis center of each axle with respect to the axis center of the turning axis.

[0012] As a desirable aspect of the drive wheels, the drive wheels further include a first intermediate shaft provided parallel to the axle on a shaft different from the axle, and a second intermediate shaft provided parallel to the axle on a shaft different from the axle and coaxial with the first intermediate shaft. The first rotational force transmission mechanism transmits the rotational force of the first input shaft to the first intermediate shaft, and includes a first rotational force connection mechanism that transmits the rotational force from the first intermediate shaft to the first wheel. The second rotational force transmission mechanism transmits the rotational force of the second input shaft to the second intermediate shaft, and includes a second rotational force connection mechanism that transmits the rotational force from the second intermediate shaft to the second wheel. The first intermediate shaft and the first rotational force connection mechanism, and the second intermediate shaft and the second rotational force connection mechanism displace and arrange the rotational axis centers of the respective wheels in a horizontal direction orthogonal to the axis center of each axle with respect to the axis center of the turning axis.

[0013] As a desirable aspect of the drive wheels, the first rotational force connection mechanism includes a first winding transmission mechanism having a pair of winding carts and an endless winding transmission member wound around each of the winding carts, and the second rotational force connection mechanism includes a second winding transmission mechanism having a pair of winding carts and an endless winding transmission member wound around each of the winding carts.

[0014] As a desirable aspect of the drive wheel, a first elastic member that supports the first rotational force connection mechanism with an elastic force by swingably providing the first rotational force connection mechanism about the first intermediate shaft, and a second elastic member that supports the second rotational force connection mechanism with an elastic force by swingably providing the second rotational force connection mechanism about the second intermediate shaft are further included.

[0015] A cart according to one aspect of the present disclosure for achieving the above object includes any one of the above drive wheels and a cart body to which the drive wheel is attached.

Effect of the Invention

[0016] According to the present disclosure, it is possible to suppress yawing while having a differential type omnidirectional movement mechanism and perform stable traveling.

Brief Description of the Drawings

[0017]

Figure 1

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Figure 8

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Figure 22

Figure 23

DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, with reference to the drawings, preferred embodiments of the drive wheel and the carriage according to the present disclosure will be described in detail. Note that the present invention is not limited by this embodiment, and when there are a plurality of embodiments, those configured by combining each embodiment are also included. In addition, the constituent elements in the embodiment include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within a so-called equivalent range.

[0019] FIG. 23 is a schematic diagram showing a configuration example of the carriage according to the embodiment.

[0020] The carriage 100 includes a carriage body 101, a handle part 102, four drive wheels 110 (120, 130, 140), a power supply unit 104, and a control device 105.

[0021] The carriage body 101 is, for example, a flat plate material and has a rectangular shape in plan view. The handle part 102 is fixed to one side in the longitudinal direction of the carriage body 101. Four drive wheels 110 are mounted at the four corners on the back side of the carriage body 101. The four drive wheels 110 are rotatable and steerable. Further, the power supply unit 104 and the control device 105 are mounted on the back surface between the front and rear drive wheels 110 of the carriage body 101. The control device 105 includes a computer system. The computer system includes a processor such as a CPU and a memory such as a ROM or a RAM. Therefore, in the carriage 100, the control device 105 controls the drive wheels 110.

[0022] The carriage body 101 constitutes a flat surface, and the object to be transported can be placed on the flat surface. That is, the carriage 100 can be configured as an automatic guided vehicle (AGV). Further, the carriage 100 can be configured as a device that travels by arranging equipment along the flat surface of the carriage body 101. Examples of the device include various devices such as a hand lifter, a forklift, a picking robot, and medical equipment.

[0023] Note that the carriage 100 and the device are not limited to the configurations described above regarding the number and arrangement of the drive wheels 110. For example, in the four-wheel form described above, the carriage 100 and the device may have a pair of drive wheels 110 attached to the rear side of the carriage 100 and a pair of driven wheels attached to the front side of the carriage 100. Also, although not shown in the figure, in a form with three or more wheels, the carriage 100 and the device may have one drive wheel 110 and all other wheels being driven wheels. Also, although not shown in the figure, in a form with three or more wheels, the carriage 100 and the device may have no driven wheels and all wheels being drive wheels 110. That is, in a form with three or more wheels, the carriage 100 and the device only need to have at least one drive wheel 110.

[0024] [Embodiment 1 of Drive Wheel] Hereinafter, the drive wheel 110 will be described in detail. FIG. 1 is a perspective view showing the configuration of the drive wheel of Embodiment 1. FIG. 2 is a plan view of the drive wheel of Embodiment 1. FIG. 3 is a front view of the drive wheel of Embodiment 1. FIG. 4 is a side view of the drive wheel of Embodiment 1. FIG. 5 is a perspective view showing the drive system of the drive wheel of Embodiment 1. FIG. 6 is a cross-sectional view (sectional view taken along line A-A in FIG. 2) showing the drive system of the drive wheel of Embodiment 1. FIG. 7 is a cross-sectional view (sectional view taken along line B-B in FIG. 4) showing the drive system of the drive wheel of Embodiment 1. FIG. 8 is a schematic diagram showing the driving force transmission path of the drive wheel of Embodiment 1.

[0025] In the following description, among the first direction, the second direction, and the third direction that intersect each other, the first direction is referred to as the "front-rear direction X", the second direction is referred to as the "width direction Y", and the third direction is referred to as the "up-down direction Z". The front-rear direction X, the width direction Y, and the up-down direction Z are perpendicular to each other. The front-rear direction X typically corresponds to the direction along which the drive wheel 110 travels straight.

[0026] The drive wheel 110 has a main body 10 fixed to the carriage main body 101 of the carriage 100 as described above. Based on this main body 10, a drive mechanism 11, a swivel part 12, a rotational force transmission mechanism 13, and a wheel 15 are provided.

[0027] The main body 10 is formed in a plate shape with its plate surface facing vertically (see FIGS. 1 to 7). The drive mechanism 11 inputs a rotational force and is provided on the main body 10. The swivel unit 12 is disposed below the main body 10. The rotational force transmission mechanism 13 transmits the rotational force input by the drive mechanism 11 to the wheels 15. The wheels 15 are rotatable by the rotational force input via the drive mechanism 11 and the rotational force transmission mechanism 13, and can be steered by the swivel unit 12.

[0028] As shown in FIGS. 1 to 6, the drive mechanism 11 includes a first drive unit 21A and a second drive unit 21B. Note that FIG. 5 is a view seen from the opposite direction of the front-rear direction X compared to FIGS. 1 and the like.

[0029] The first drive unit 21A is composed of a motor. The first drive unit 21A is attached to the main body 10 such that the axis O6 (see FIG. 6) of the first drive shaft 21Ac extends along the vertical direction Z.

[0030] The second drive unit 21B is composed of a motor. The second drive unit 21B is attached to the main body 10 such that the axis O7 (see FIG. 6) of the second drive shaft 21Bc extends along the vertical direction Z.

[0031] The swivel unit 12 includes a swivel shaft 35 and a support member 36. The swivel shaft 35 has the center of the disc shape as the axis O1 and is rotatably supported via a bearing 45 (see FIGS. 6 and 7) provided between the swivel shaft 35 and the main body 10. Thereby, the swivel shaft 35 is supported so as to be relatively rotatable about the axis O1 with respect to the main body 10. The support member 36 is integrally provided on the plate-shaped lower surface of the swivel shaft 35.

[0032] The swivel unit 12 is disposed to penetrate vertically in the Z direction coaxially with the first input shaft 25A about the axis O1, and is rotatably supported with respect to the support member 36 via a bearing 43b (see FIG. 6). The first input shaft 25A is rotatably supported with respect to the main body 10 coaxially with the axis O1 via a bearing 43a (see FIG. 6). Accordingly, the first input shaft 25A is supported so as to be relatively rotatable about the axis O1 with respect to the swivel unit 12, and is also supported so as to be relatively rotatable about the axis O1 with respect to the main body 10. That is, the swivel unit 12 is provided so as to be rotatable with respect to the main body 10 regardless of the rotation of the first input shaft 25A. For this reason, the drive wheel 110 of the embodiment can input a rotational force to the first input shaft 25A on the axis O1 which is the swivel axis of the wheel 15.

[0033] The swivel unit 12 is disposed along the second input shaft 25B in the vertical direction Z. The second input shaft 25B is inserted through the first input shaft 25A and is rotatably disposed outside the first input shaft 25A via a bearing 44 (see FIG. 6). Accordingly, the second input shaft 25B is supported so as to be relatively rotatable about the axis O1 with respect to the swivel unit 12 via the first input shaft 25A, and is also supported so as to be relatively rotatable about the axis O1 with respect to the main body 10. That is, the swivel unit 12 is provided so as to be rotatable with respect to the main body 10 regardless of the rotation of the second input shaft 25B. For this reason, the drive wheel 110 of the embodiment can input a rotational force to the second input shaft 25B on the axis O1 which is the swivel axis of the wheel 15. With such a configuration, the first input shaft 25A, the second input shaft 25B, and the swivel unit 12 are rotatably disposed coaxially along the axis O1.

[0034] In the slewing section 12, the support member 36 supports the wheels 15. The wheels 15 are provided on the axle 37. The axle 37 is provided along the direction (the width direction Y in the figure) in which the axis O2 (see FIGS. 3, 4, and 6) orthogonal to the axis O1 extends. In the drive wheel 110 of the embodiment, the axle 37 is fixed to the support member 36. The wheels 15 are provided with a pair of first and second wheels 15A and 15B having the same diameter. As shown in FIG. 7, for the first wheel 15A and the second wheel 15B, one of the first wheels 15A is rotatably provided about the axis O2 with respect to one end of the axle 37 via a bearing 48A, and the other second wheel 15B is rotatably provided about the axis O2 with respect to the other end of the axle 37 via a bearing 48B.

[0035] In the slewing section 12, the support member 36 supports the output shaft 40. The output shaft 40 is provided along the axis O3 extending in the horizontal direction (width direction Y) orthogonal to the direction (vertical direction Z) in which the axis O1 extends. The output shaft 40 is fixed to the support member 36.

[0036] As shown in FIGS. 5 and 7, the rotational force transmission mechanism 13 includes a first rotational force transmission mechanism 13A and a second rotational force transmission mechanism 13B.

[0037] The first rotational force transmission mechanism 13A transmits the rotational force of the first drive unit 21A to the first input shaft 25A and transmits the rotational force of the first input shaft 25A to the first wheel 15A. The first rotational force transmission mechanism 13A includes a first drive gear 31A, a first driven gear 32A, a first conversion gear 41A, a first conversion output gear 42A, a first transmission gear 38A, and a first transmission output gear 39A. In the drive wheel 110 of the embodiment, the first drive gear 31A and the first driven gear 32A, the first transmission gear 38A and the first transmission output gear 39A are constituted by spur gears, and the first conversion gear 41A and the first conversion output gear 42A are constituted by bevel gears.

[0038] In the first rotational force transmission mechanism 13A, the first driving gear 31A is fixed to the first driving shaft 21Ac of the first driving unit 21A. Therefore, the first driving gear 31A rotates about the axis O6 of the first driving shaft 21Ac by the rotational force with which the first driving unit 21A is driven. The first driven gear 32A is fixed to the upper end portion of the first input shaft 25A. Therefore, the first driven gear 32A rotates about the axis O1 of the first input shaft 25A. The first conversion gear 41A is fixed to the lower end portion of the first input shaft 25A. Therefore, the first conversion gear 41A rotates about the axis O1 of the first input shaft 25A together with the first driven gear 32A. The first conversion output gear 42A is rotatably provided with respect to the output shaft 40 via a bearing 47A. Therefore, the first conversion output gear 42A rotates about the axis O3 of the output shaft 40. The first transmission gear 38A is integrally formed with the first conversion output gear 42A and is rotatably provided with respect to the output shaft 40 via a bearing 47A. Therefore, the first transmission gear 38A rotates about the axis O3 of the output shaft 40 integrally with the first conversion output gear 42A. The first transmission output gear 39A is integrally formed with the first wheel 15A and is rotatably provided with respect to the axle 37 via a bearing 48A. Therefore, the first transmission output gear 39A rotates about the axis O2 of the axle 37 integrally with the first wheel 15A.

[0039] And in the first rotational force transmission mechanism 13A, the first driving gear 31A meshes with the first driven gear 32A. The first conversion gear 41A meshes with the first conversion output gear 42A. The first transmission gear 38A meshes with the first transmission output gear 39A in its front-rear direction X. Therefore, the first rotational force transmission mechanism 13A transmits the rotational force of the first driving unit 21A from the first driving gear 31A to the first driven gear 32A to apply a rotational force to the first input shaft 25A, and further transmits the rotational force of the first input shaft 25A from the first conversion gear 41A to the first conversion output gear 42A to convert the direction of rotation to the output shaft 40, and transmits the rotational force of the first conversion output gear 42A from the first transmission gear 38A to the first transmission output gear 39A to apply a rotational force to the first wheel 15A.

[0040] The second rotational force transmission mechanism 13B transmits a rotational force that rotates in the opposite direction to the first input shaft 25A of the second input shaft 25B at the same speed and in the same direction and at the same rotational speed as the first wheel 15A to the second wheel 15B. The second rotational force transmission mechanism 13B includes a second drive gear 31B, a second driven gear 32B, a second conversion gear 41B, a second conversion output gear 42B, a second transmission gear 38B, and a second transmission output gear 39B. In the drive wheel 110 of the embodiment, the second drive gear 31B and the second driven gear 32B, the second transmission gear 38B and the second transmission output gear 39B are constituted by spur gears, and the second conversion gear 41B and the second conversion output gear 42B are constituted by bevel gears.

[0041] In the second rotational force transmission mechanism 13B, the second drive gear 31B is fixed to the second drive shaft 21Bc of the second drive unit 21B. Therefore, the second drive gear 31B rotates about the axis O7 of the second drive shaft 21Bc by the rotational force by which the second drive unit 21B is driven. The second driven gear 32B is fixed to the upper end portion of the second input shaft 25B. Therefore, the second driven gear 32B rotates about the axis O1 of the second input shaft 25B. The second conversion gear 41B is fixed to the lower end portion of the second input shaft 25B. Therefore, the second conversion gear 41B rotates about the axis O1 of the second input shaft 25B together with the second driven gear 32B. The second conversion output gear 42B is rotatably provided with respect to the output shaft 40 via a bearing 47B. Therefore, the second conversion output gear 42B rotates about the axis O3 of the output shaft 40. The second transmission gear 38B is integrally formed with the second conversion output gear 42B and is rotatably provided with respect to the output shaft 40 via a bearing 47B. Therefore, the second transmission gear 38B rotates about the axis O3 of the output shaft 40 integrally with the second conversion output gear 42B. The second transmission output gear 39B is integrally formed with the second wheel 15B and is rotatably provided with respect to the axle 37 via a bearing 48B. Therefore, the second transmission output gear 39B rotates about the axis O2 of the axle 37 integrally with the second wheel 15B.

[0042] And in the second rotational force transmission mechanism 13B, the second drive gear 31B meshes with the second driven gear 32B. The second conversion gear 41B meshes with the second conversion output gear 42B. The second transmission gear 38B meshes with the second transmission output gear 39B in its front-rear direction X. Therefore, the second rotational force transmission mechanism 13B transmits the rotational force of the second drive unit 21B from the second drive gear 31B to the second driven gear 32B to apply a rotational force to the second input shaft 25B, further transmits the rotational force of the second input shaft 25B from the second conversion gear 41B to the second conversion output gear 42B to convert the direction of rotation to the output shaft 40, and transmits the rotational force of the second conversion output gear 42B from the second transmission gear 38B to the second transmission output gear 39B to apply a rotational force to the second wheel 15B.

[0043] Also, as shown in FIGS. 2, 4, 6, and 7, in the drive wheel 110 of the embodiment, the rotation axis O5 of the wheels (the first wheel 15A and the second wheel 15B) is offset (displaced) in the horizontal direction (front-rear direction X) orthogonal to the axis O1 of the turning shaft 35. The rotation axis O5 of the wheels intersects the axis O2 of the axle 37 and extends along the vertical direction, and is a straight line parallel to the axis O1 passing through the center between the respective wheels 15A, 15B (the center between the points where the wheels 15A, 15B contact the ground). Such a configuration in which the rotation axis O5 of the wheels (the first wheel 15A and the second wheel 15B) is offset (displaced) in the horizontal direction (front-rear direction X) orthogonal to the axis O1 of the turning shaft 35 is achieved in the drive wheel 110 of the embodiment by the first transmission output gear 39A meshing with the first transmission gear 38A in the front-rear direction X, and the second transmission output gear 39B meshing with the second transmission gear 38B in the front-rear direction X.

[0044] This drive wheel 110 can rotate the first input shaft 25A and the second input shaft 25B by the drive mechanism 11 to rotate and steer each wheel 15A, 15B. For example, when the first input shaft 25A and the second input shaft 25B are rotated in opposite directions and the first wheel 15A and the second wheel 15B are rotated in the same direction, and the rotational speeds (rotation speeds) of the first wheel 15A and the second wheel 15B are made the same, by applying a rotational force to the first input shaft 25A and the second input shaft 25B, each wheel 15A, 15B can be rotated without being steered. At this time, by making the rotational speeds (rotation speeds) of the first wheel 15A and the second wheel 15B different, each wheel 15A, 15B can be steered while being rotated or stopped.

[0045] Here, the operation of the drive wheel 110 will be described with reference to FIG. 8. In FIG. 8, for convenience, the wheels (the first wheel 15A and the second wheel 15B) are shown expanded in the vertical direction. When the drive wheel 110 rotates the first input shaft 25A in the A1 direction, the first conversion gear 41A provided on the first input shaft 25A rotates in the same direction, and the first conversion output gear 42A meshing with the first conversion gear 41A rotates in the A2 direction. When the first conversion output gear 42A rotates in the A2 direction, the first transmission gear 38A provided integrally with the first conversion output gear 42A rotates in the same direction. Then, the first transmission output gear 39A meshing with the first transmission gear 38A rotates in the C1 direction opposite to the A2 direction, and the first wheel 15A provided integrally with the first transmission output gear 39A is rotated in the same direction. On the other hand, when the drive wheel 110 rotates the second input shaft 25B in the B1 direction opposite to the A1 direction, the second conversion gear 41B provided on the second input shaft 25B rotates in the same direction, and the second conversion output gear 42B meshing with the second conversion gear 41B rotates in the B2 direction. When the second conversion output gear 42B rotates in the B2 direction, the second transmission gear 38B provided integrally with the second conversion output gear 42B rotates in the same direction. Then, the second transmission output gear 39B meshing with the second transmission gear 38B rotates in the C2 direction opposite to the B2 direction and the same as the C1 direction, and the second wheel 15B provided integrally with the second transmission output gear 39B is rotated in the same direction.

[0046] At this time, when the drive wheel 110 reduces the rotational speed of the second input shaft 25B with respect to the rotational speed of the first input shaft 25A so as to reduce the rotational speed of the second wheel 15B with respect to the rotational speed of the first wheel 15A, the turning shaft 35 rotates by the difference in rotational speed between the first wheel 15A and the second wheel 15B, and the first wheel 15A and the second wheel 15B turn and steer while being used for traveling. Further, when the drive wheel 110 stops the rotation of the first input shaft 25A or the second input shaft 25B, the rotational speed input to the first wheel 15A or the rotational speed input to the second wheel 15B becomes 0, and the first wheel 15A and the second wheel 15B turn and steer without being used for traveling.

[0047] The drive wheel 110 of such an embodiment includes the first input shaft 25A and the second input shaft 25B on the same axis, the axle 37 provided to intersect the first input shaft 25A, the first wheel 15A and the second wheel 15B provided on the axle 37, the turning shaft 35 rotatably provided on the same axis as the first input shaft 25A and the second input shaft 25B and supporting the respective wheels 15A, 15B so as to be turnable via the axle 37, the first rotational force transmission mechanism 13A that transmits the rotational force of the first input shaft 25A to the first wheel 15A, and the second rotational force transmission mechanism 13B that transmits a rotational force having the same speed as the first input shaft 25A but rotating in the opposite direction to the second input shaft 25B to the second wheel 15B in the same direction and at the same rotational speed as the first wheel 15A.

[0048] This drive wheel 110 has a differential type omnidirectional movement mechanism. That is, in the drive wheel 110, the rotational force of the first input shaft 25A is transmitted to the first wheel 15A by the first rotational force transmission mechanism 13A, and the rotational force of the second input shaft 25B is transmitted to the second wheel 15B by the second rotational force transmission mechanism 13B. This drive wheel 110 can switch the rotation of each of the wheels 15A, 15B and the steering of each of the wheels 15A, 15B by adjusting the rotational speeds of the first input shaft 25A and the second input shaft 25B.

[0049] In particular, in this drive wheel 110, the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B rotate the first input shaft 25A and the second input shaft 25B at the same speed in reverse rotation, and transmit this rotation to each of the wheels 15A and 15B in the same direction and at the same rotational speed. For this drive wheel 110, for example, the drive wheel described in Patent Document 1 has a configuration in which rotational force is transmitted from each input shaft extending vertically to each axle extending horizontally by meshing of bevel gears, and since the rotational directions of the two input shafts are the same, yawing that sways left and right occurs when moving forward and backward, which generates a force to rotate the turning axis. For example, an external force that causes turning is applied during straight travel, making the driving unstable. In this regard, the drive wheel 110 of the embodiment can perform stable driving while suppressing yawing because, by rotating the input shafts 25A and 25B on the same axis in reverse rotation, an external force that causes turning is not applied, for example, during straight travel.

[0050] Also, in this drive wheel 110, the first rotational force transmission mechanism 13A is composed of a first conversion gear 41A and a first conversion output gear 42A that are provided on axes (the first input shaft 25A and the output shaft 40) perpendicular to each other and mesh with each other, and are composed of bevel gears. The second rotational force transmission mechanism 13B is composed of a second conversion gear 41B and a second conversion output gear 42B that are provided on axes (the second input shaft 25B and the output shaft 40) perpendicular to each other and mesh with each other, and are composed of bevel gears.

[0051] As described above, the drive wheel described in Patent Document 1 has a configuration in which rotational force is transmitted from each input shaft extending vertically to each axle extending horizontally by meshing of bevel gears, and since the rotational directions of the two input shafts are the same, yawing that sways left and right occurs when moving forward and backward, which generates a force to rotate the turning axis. For example, an external force that causes turning is applied during straight travel, making the driving unstable. In this regard, even if this drive wheel 110 employs a rotation transmission mechanism composed of bevel gears provided on intersecting axes and meshing with each other, by rotating the input shafts 25A and 25B on the same axis in reverse rotation, an external force that causes turning is not applied, for example, during straight travel. Therefore, yawing can be suppressed and stable driving can be performed.

[0052] In addition, this drive wheel 110 further includes an output shaft 40 provided so as to intersect the first input shaft 25A and the second input shaft 25B. The first rotational force transmission mechanism 13A transmits the rotational force of the first input shaft 25A as a rotation around the output shaft 40 to the first wheel 15A, and the second rotational force transmission mechanism 13B transmits the rotational force of the second input shaft 25B as a rotation around the output shaft 40 to the second wheel 15B.

[0053] According to this drive wheel 110, the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B perform the transmission of the rotational force around the output shaft 40 extending in different directions from the coaxial first input shaft 25A and second input shaft 25B, realizing turning and steering.

[0054] In addition, in this drive wheel 110, the rotational axis centers O5 of the respective wheels 15A, 15B are arranged so as to be displaced in a horizontal direction orthogonal to the axis center O2 of the axle 37 with respect to the axis center O1 of the turning axis 35.

[0055] According to this drive wheel 110, when the respective wheels 15A, 15B are not being driven, the respective wheels 15A, 15B can be passively turned by an external force acting in the horizontal direction. That is, the carriage 100 can be automatically traveled and automatically steered, and an operator can manually travel and manually steer it.

[0056] In addition, the carriage 100 of the embodiment includes the above-described drive wheel 110 and a carriage body 101 to which the drive wheel 110 is attached. Therefore, the carriage 100 can perform stable traveling while having a differential-type omnidirectional movement mechanism.

[0057] [Embodiment 2 of the drive wheel] FIG. 9 is a perspective view showing the basic configuration of the drive wheel of Embodiment 2. FIG. 10 is a cross-sectional view showing the drive system of the drive wheel of Embodiment 2. FIG. 11 is a cross-sectional view showing the drive system of the drive wheel of Embodiment 2. FIG. 12 is a schematic diagram showing the driving force transmission path of the drive wheel of Embodiment 2.

[0058] The drive wheel 120 of Embodiment 2 mainly differs from the drive wheel 110 of Embodiment 1 described above in the configuration of the rotational force transmission mechanism 13, the configuration of the output shaft 40, and the configuration of the axle 37. In the following description of the drive wheel 120 of Embodiment 2, the same reference numerals are given to the parts equivalent to the drive wheel 110 described above, and the description thereof is omitted.

[0059] The output shaft includes an intersecting output shaft 40A and a parallel output shaft 40B.

[0060] The intersecting output shaft 40A is provided so as to intersect the first input shaft 25A. The intersecting output shaft 40A is provided along an axis O3 that extends orthogonal to the axis O1 of the first input shaft 25A (the second input shaft 25B and the turning shaft 35) on a different axis from the first input shaft 25A. As shown in FIG. 10, the intersecting output shaft 40A is rotatably provided around the axis O3 with respect to the support member 36 via a bearing 47A.

[0061] The parallel output shaft 40B is provided parallel to the second input shaft 25B. The parallel output shaft 40B is provided along an axis O4 that extends parallel to the axis O1 of the second input shaft 25B (the first input shaft 25A and the turning shaft 35) on a different axis from the second input shaft 25B. As shown in FIG. 11, the parallel output shaft 40B is rotatably provided around the axis O4 with respect to the support member 36 via a bearing 47B.

[0062] The axle includes a first axle 37A and a second axle 37B.

[0063] The first axle 37A is provided along an axis O2 that intersects (is orthogonal to) the axis O1 of the first input shaft 25A, the second input shaft 25B, and the turning shaft 35. As shown in FIG. 11, the first axle 37A is rotatably provided around the axis O2 with respect to the support member 36 via a bearing 48A.

[0064] The second axle 37B is provided along an axis O2 that intersects (is orthogonal to) the axes O1 of the first input shaft 25A, the second input shaft 25B, and the swivel shaft 35. As shown in FIG. 11, the second axle 37B is rotatably provided about the axis O2 via a bearing 48B with respect to the support member 36. The second axle 37B is provided coaxially with the first axle 37A and is provided side by side with the first axle 37A along the axis O2.

[0065] As shown in FIGS. 9 to 11, the rotational force transmission mechanism 13 includes a first rotational force transmission mechanism 13A and a second rotational force transmission mechanism 13B.

[0066] The first rotational force transmission mechanism 13A transmits the rotational force of the first drive unit 21A to the first input shaft 25A, and transmits the rotational force of the first input shaft 25A to the first wheel 15A as rotation around the intersecting output shaft 40A. The first rotational force transmission mechanism 13A includes a first drive gear 31A, a first driven gear 32A, a first conversion gear 41A, a first conversion output gear 42A, a first transmission gear 38A, and a first transmission output gear 39A. In the drive wheel 120 of the embodiment, the first drive gear 31A and the first driven gear 32A, the first transmission gear 38A and the first transmission output gear 39A are constituted by spur gears, and the first conversion gear 41A and the first conversion output gear 42A are constituted by bevel gears.

[0067] In the first rotational force transmission mechanism 13A, the first driving gear 31A is fixed to the first driving shaft 21Ac of the first driving unit 21A. Therefore, the first driving gear 31A rotates about the axis O6 of the first driving shaft 21Ac by the rotational force with which the first driving unit 21A is driven. The first driven gear 32A is fixed to the upper end portion of the first input shaft 25A. Therefore, the first driven gear 32A rotates about the axis O1 of the first input shaft 25A. The first conversion gear 41A is fixed to the lower end portion of the first input shaft 25A. Therefore, the first conversion gear 41A rotates about the axis O1 of the first input shaft 25A together with the first driven gear 32A. The first conversion output gear 42A is fixed to the intersecting output shaft 40A. Therefore, the first conversion output gear 42A rotates about the axis O3 of the intersecting output shaft 40A. The first transmission gear 38A is integrally formed with the first conversion output gear 42A and fixed to the intersecting output shaft 40A. Therefore, the first transmission gear 38A rotates about the axis O3 of the intersecting output shaft 40A integrally with the first conversion output gear 42A. The first transmission output gear 39A is integrally formed with the first wheel 15A and fixed to the first axle 37A. Therefore, the first transmission output gear 39A rotates about the axis O2 of the first axle 37A integrally with the first wheel 15A.

[0068] And in the first rotational force transmission mechanism 13A, the first driving gear 31A meshes with the first driven gear 32A. The first conversion gear 41A meshes with the first conversion output gear 42A. The first transmission gear 38A meshes with the first transmission output gear 39A in its front-rear direction X. Therefore, the first rotational force transmission mechanism 13A transmits the rotational force of the first driving unit 21A from the first driving gear 31A to the first driven gear 32A to apply a rotational force to the first input shaft 25A, and further transmits the rotational force of the first input shaft 25A from the first conversion gear 41A to the first conversion output gear 42A to convert the direction of rotation to the intersecting output shaft 40A, and transmits the rotational force of the first conversion output gear 42A from the first transmission gear 38A to the first transmission output gear 39A to apply a rotational force to the first wheel 15A.

[0069] The second rotational force transmission mechanism 13B transmits a rotational force that rotates in the opposite direction to the first input shaft 25A of the second input shaft 25B at the same speed and in the same direction and at the same rotational speed as the first wheel 15A to the second wheel 15B. The second rotational force transmission mechanism 13B includes a second drive gear 31B, a second driven gear 32B, a second connecting gear 33B, a second connecting output gear 34B, a second conversion gear 41B, and a second conversion output gear 42B. In the drive wheel 120 of the embodiment, the second drive gear 31B and the second driven gear 32B, and the second connecting gear 33B and the second connecting output gear 34B are constituted by spur gears, and the second conversion gear 41B and the second conversion output gear 42B are constituted by bevel gears.

[0070] In the second rotational force transmission mechanism 13B, the second drive gear 31B is fixed to the second drive shaft 21Bc of the second drive unit 21B. Therefore, the second drive gear 31B rotates about the axis O7 of the second drive shaft 21Bc by the rotational force with which the second drive unit 21B is driven. The second driven gear 32B is fixed to the upper end portion of the second input shaft 25B. Therefore, the second driven gear 32B rotates about the axis O1 of the second input shaft 25B. The second connecting gear 33B is fixed to the lower end portion of the second input shaft 25B. Therefore, the second connecting gear 33B rotates about the axis O1 of the second input shaft 25B together with the second driven gear 32B. The second connecting output gear 34B is fixed to the upper side of the parallel output shaft 40B. Therefore, the second connecting output gear 34B rotates about the axis O4 of the parallel output shaft 40B. The second conversion gear 41B is fixed to the lower side of the parallel output shaft 40B. Therefore, the second conversion gear 41B rotates about the axis O4 of the parallel output shaft 40B together with the second connecting output gear 34B. The second conversion output gear 42B is integrally formed with the second wheel 15B and is fixed to the second axle 37B. Therefore, the second conversion output gear 42B rotates about the axis O2 of the second axle 37B integrally with the second wheel 15B.

[0071] And in the second rotational force transmission mechanism 13B, the second drive gear 31B meshes with the second driven gear 32B. The second connecting gear 33B meshes with the second connecting output gear 34B in the front-rear direction X thereof. The second conversion gear 41B meshes with the second conversion output gear 42B. Therefore, the second rotational force transmission mechanism 13B transmits the rotational force of the second drive unit 21B from the second drive gear 31B to the second driven gear 32B to apply a rotational force to the second input shaft 25B, and further transmits the rotational force of the second input shaft 25B from the second connecting gear 33B to the second connecting output gear 34B to change the rotational position in the front-rear direction X and apply a rotational force to the parallel output shaft 40B, and transmits the rotational force of the parallel output shaft 40B from the first conversion gear 41A to the first conversion output gear 42A to change the rotational direction to the second axle 37B and apply a rotational force to the second wheel 15B.

[0072] Also, as shown in FIGS. 9 to 11, in the drive wheel 120 of the embodiment, the rotational axis O5 of the wheels (the first wheel 15A and the second wheel 15B) is displaced (offset) in the horizontal direction (front-rear direction X) orthogonal to the axis O1 of the turning shaft 35. The rotational axis O5 of the wheels intersects the axes O2 of the respective axles 37A, 37B and extends along the vertical direction, and is a straight line passing through the center between the respective wheels 15A, 15B (the center between the points where the wheels 15A, 15B contact the ground) and parallel to the axis O1. In the drive wheel 120 of the embodiment, such a configuration in which the rotational axis O5 of the wheels (the first wheel 15A and the second wheel 15B) is displaced (offset) in the horizontal direction (front-rear direction X) orthogonal to the axis O1 of the turning shaft 35 is achieved by the first transmission output gear 39A meshing with the first transmission gear 38A in the front-rear direction X and the second connecting output gear 34B meshing with the second connecting gear 33B in the front-rear direction X.

[0073] The drive wheel 120 can rotate the first input shaft 25A and the second input shaft 25B by the drive mechanism 11 to rotate and steer each of the wheels 15A and 15B. For example, by rotating the first input shaft 25A and the second input shaft 25B in opposite directions and applying a rotational force to the first input shaft 25A and the second input shaft 25B so that the first wheel 15A and the second wheel 15B rotate in the same direction and the rotational speeds (rotation rates) of the first wheel 15A and the second wheel 15B are the same, the wheels 15A and 15B can rotate without being steered. At this time, by making the rotational speeds (rotation rates) of the first wheel 15A and the second wheel 15B different, the wheels 15A and 15B can be steered in a rotating or stopped state.

[0074] Here, the operation of the drive wheel 120 will be described with reference to FIG. 12. In FIG. 12, for the sake of convenience, the wheels (the first wheel 15A and the second wheel 15B) are shown unfolded in the vertical direction. When the drive wheel 120 rotates the first input shaft 25A in the A1 direction, the first conversion gear 41A provided on the first input shaft 25A rotates in the same direction, and the first conversion output gear 42A meshing with the first conversion gear 41A rotates in the A2 direction. When the first conversion output gear 42A rotates in the A2 direction, the first transmission gear 38A provided integrally with the first conversion output gear 42A rotates in the same direction. Then, the first transmission output gear 39A meshing with the first transmission gear 38A rotates in the C1 direction opposite to the A2 direction, and the first wheel 15A provided integrally with the first transmission output gear 39A rotates in the same direction. On the other hand, when the drive wheel 120 rotates the second input shaft 25B in the B1 direction opposite to the A1 direction, the second driven gear 32B and the second connection gear 33B provided on the second input shaft 25B rotate in the same direction, and the second connection output gear 34B meshing with the second connection gear 33B rotates in the B2 direction opposite to the B1 direction. When the second connection output gear 34B rotates in the B2 direction, the second conversion gear 41B provided integrally with the second connection output gear 34B via the parallel output shaft 40B rotates in the same direction. Then, the second conversion output gear 42B meshing with the second conversion gear 41B rotates in the C2 direction the same as the C1 direction of the first wheel 15A, and the second wheel 15B provided integrally with the second conversion output gear 42B rotates in the same direction.

[0075] At this time, when the drive wheel 120 reduces the rotational speed of the second input shaft 25B with respect to the rotational speed of the first input shaft 25A so as to reduce the rotational speed of the second wheel 15B with respect to the rotational speed of the first wheel 15A, the turning shaft 35 rotates by the rotational speed difference between the first wheel 15A and the second wheel 15B, and the first wheel 15A and the second wheel 15B turn and steer while being used for traveling. Further, when the drive wheel 120 stops the rotation of the first input shaft 25A or the second input shaft 25B, the rotational speed input to the first wheel 15A or the rotational speed input to the second wheel 15B becomes 0, and the first wheel 15A and the second wheel 15B turn and steer without being used for traveling.

[0076] The drive wheel 120 of such an embodiment includes, similarly to the drive wheel 110, a first input shaft 25A and a second input shaft 25B on the same axis, axles 37, 37B provided so as to intersect the first input shaft 25A, a first wheel 15A and a second wheel 15B provided on the axles 37, 37B, a turning shaft 35 rotatably provided on the same axis as the first input shaft 25A and the second input shaft 25B and supporting each wheel 15A, 15B so as to be turnable via the axles 37, 37B, a first rotational force transmission mechanism 13A that transmits the rotational force of the first input shaft 25A to the first wheel 15A, and a second rotational force transmission mechanism 13B that transmits a rotational force having the same speed as the first input shaft 25A but rotating in the opposite direction to the second wheel 15B in the same direction and at the same rotational speed as the first wheel 15A.

[0077] This drive wheel 120 has, similarly to the drive wheel 110, a differential type omnidirectional movement mechanism and can perform stable traveling while suppressing yawing.

[0078] Further, in this drive wheel 120, the first rotational force transmission mechanism 13A includes a first conversion gear 41A and a first conversion output gear 42A provided on axes (the first input shaft 25A and the intersecting output shaft 40A) orthogonal to each other and meshing with each other, and the first conversion gear 41A and the first conversion output gear 42A are constituted by bevel gears. The second rotational force transmission mechanism 13B includes a second conversion gear 41B and a second conversion output gear 42B provided on axes (the parallel output shaft 40B and the second axle 37B) orthogonal to each other and meshing with each other, and the second conversion gear 41B and the second conversion output gear 42B are constituted by bevel gears.

[0079] Similar to the drive wheel 110, this drive wheel 120 can also adopt a rotation transmission mechanism composed of bevel gears provided on intersecting axes and meshing with each other, and has a differential omnidirectional movement mechanism, which can suppress yawing and perform stable driving.

[0080] In addition, this drive wheel 120 further includes an intersecting output shaft 40A provided parallel to the vehicle axle (the first vehicle axle 37A) and intersecting the first input shaft 25A, and a parallel output shaft 40B provided parallel to the second input shaft 25B and intersecting the vehicle axle (the second vehicle axle 37B). The first rotation force transmission mechanism 13A transmits the rotation force of the first input shaft 25A to the first wheel 15A as rotation around the intersecting output shaft 40A, and the second rotation force transmission mechanism 13B transmits the rotation force of the second input shaft 25B to the second wheel 15B as rotation around the parallel output shaft 40B.

[0081] Here, in the drive wheel 110 described above, since the rotation direction is converted from the axis center O1 of the coaxial turning shaft 35 to the output shaft 40 in the paths of the first rotation force transmission mechanism 13A and the second rotation force transmission mechanism 13B, different gears for converting the rotation direction had to be used in the first rotation force transmission mechanism 13A and the second rotation force transmission mechanism 13B. Usually, when considering the strength of the gears, the design is made according to the smaller gears, and the larger gears become over-specification, so it is desired to make the sizes of the gears the same as much as possible. In this regard, according to the drive wheel 120, in the path of the first rotation force transmission mechanism 13A, the rotation direction is converted from the axis center O1 of the turning shaft 35 to the intersecting output shaft 40A, and then the rotation force is transmitted to the first wheel 15A of the first vehicle axle 37A. In the path of the second rotation force transmission mechanism 13B, the rotation position is changed from the axis center O1 of the turning shaft 35 to the parallel output shaft 40B, and further the rotation direction is converted from the parallel output shaft 40B to the second vehicle axle 37B to transmit the rotation force to the second wheel 15B. Thereby, according to the drive wheel 120, the same gears can be used for converting the rotation direction in the first rotation force transmission mechanism 13A and the second rotation force transmission mechanism 13B, so that the strengths of the parts can be matched and the parts can be easily procured.

[0082] Further, in this drive wheel 120, the rotation axes O5 of the respective wheels 15A and 15B are displaced and arranged in a horizontal direction orthogonal to the axis O2 of each axle 37A and 37B with respect to the axis O1 of the turning axis 35.

[0083] According to this drive wheel 120, when the respective wheels 15A and 15B are not driven, the respective wheels 15A and 15B can be passively turned by an external force acting in the horizontal direction. That is, the carriage 100 can be automatically traveled and automatically steered, and an operator can manually travel and manually steer it.

[0084] Further, the carriage 100 of the embodiment includes the above-described drive wheel 120 and a carriage main body 101 to which the drive wheel 120 is attached. Therefore, the carriage 100 can perform stable traveling while including a differential type omnidirectional movement mechanism.

[0085] [Embodiment 3 of Drive Wheel] FIG. 13 is a perspective view showing the configuration of the drive wheel of Embodiment 3. FIG. 14 is a front view of the drive wheel of Embodiment 3. FIG. 15 is a side view of the drive wheel of Embodiment 3. FIG. 16 is a perspective view showing the drive system of the drive wheel of Embodiment 3. FIG. 17 is a cross-sectional view (E-E cross-sectional view of FIG. 15) showing the drive system of the drive wheel of Embodiment 3. FIG. 18 is a cross-sectional view (F-F cross-sectional view of FIG. 15) showing the drive system of the drive wheel of Embodiment 3. FIG. 19 is a cross-sectional view (G-G cross-sectional view of FIG. 15) showing the drive system of the drive wheel of Embodiment 3. FIG. 20 is a schematic diagram showing the driving force transmission path of the drive wheel of Embodiment 3.

[0086] The drive wheel 130 of Embodiment 3 is mainly different from the above-described drive wheel 110 in the configuration of the rotational force transmission mechanism 13, the configuration of the output shaft 40, and the configuration of the axle 37. In particular, the drive wheel 130 of Embodiment 3 is mainly different from the above-described drive wheel 110 in that the rotational force transmission mechanism 13 includes a first rotational force connection mechanism 16A and a second rotational force connection mechanism 16B. The drive wheel 130 of Embodiment 3 targets the first rotational force connection mechanism 16A and the second rotational force connection mechanism 16B as features. In the following description of the drive wheel 130 of Embodiment 3, the same reference numerals are given to the equivalent parts as those of the above-described drive wheel 110, and the description thereof is omitted.

[0087] The output shaft includes a first parallel output shaft 40A and a second parallel output shaft 40B.

[0088] The first parallel output shaft 40A is provided in parallel with the first input shaft 25A. The first parallel output shaft 40A is provided on a shaft different from the first input shaft 25A, along an axis O3 that extends parallel to the axis O1 of the first input shaft 25A (the second input shaft 25B and the turning shaft 35). As shown in FIG. 18, the first parallel output shaft 40A is rotatably provided about the axis O3 with respect to the turning shaft 35 via a bearing 46.

[0089] The second parallel output shaft 40B is provided in parallel with the second input shaft 25B. The second parallel output shaft 40B is provided on a shaft different from the second input shaft 25B, along an axis O4 that extends parallel to the axis O1 of the second input shaft 25B (the first input shaft 25A and the turning shaft 35). As shown in FIG. 18, the second parallel output shaft 40B is rotatably provided about the axis O4 with respect to the turning shaft 35 via a bearing 47.

[0090] In the turning section 12, a first support member 36Aa and a second support member 36Ba are fixed to the lower side of the turning shaft 35 for the drive wheel 130. The first support member 36Aa and the second support member 36Ba are provided to face each other in the width direction Y on the drawing. Also, in the turning section 12 of the drive wheel 130, a first swing support member 36Ab is provided on the first support member 36Aa, and a second swing support member 36Bb is provided on the second support member 36Ba.

[0091] The axle includes a first axle 37A and a second axle 37B.

[0092] The first axle 37A (see FIGS. 16 and 19) is provided coaxially with the second axle 37B as will be described later, and is provided along an axis O2 that intersects (is orthogonal to) the axis O1 of the first input shaft 25A, the second input shaft 25B, and the turning shaft 35 shown in FIG. 17. As shown in FIG. 19, the first axle 37A is rotatably provided about the axis O2 with respect to the first swing support member 36Ab via a bearing 48A.

[0093] The second axle 37B (see FIGS. 15, 16, and 19) is provided along an axis O2 that intersects (is orthogonal to) the axes O1 of the first input shaft 25A, the second input shaft 25B, and the swivel shaft 35 shown in FIG. 17, in the same manner as the first axle 37A. As shown in FIG. 19, the second axle 37B is rotatably provided about the axis O2 with respect to the second swing support member 36Bb via a bearing 48B. The second axle 37B is provided coaxially with the first axle 37A and is provided side by side with the first axle 37A along the axis O2.

[0094] The drive wheels 130 include a first intermediate shaft 50A and a second intermediate shaft 50B.

[0095] As shown in FIG. 14, the first intermediate shaft 50A is provided along an axis O8 that extends parallel to the axis O2 of the first axle 37A on a different axis from the first axle 37A. As shown in FIG. 18, the first intermediate shaft 50A is rotatably provided about the axis O8 with respect to the first support member 36Aa via a bearing 51Aa. Further, the first intermediate shaft 50A is rotatably provided about the axis O8 with respect to the first swing support member 36Ab via a bearing 51Ab. Therefore, the first swing support member 36Ab is attached to the first support member 36Aa fixed to the swivel shaft 35 via the first intermediate shaft 50A and is provided to be swingable about the axis O8. For this reason, the first axle 37A provided on the first swing support member 36Ab is provided to be swingable about the axis O8 integrally with the first swing support member 36Ab.

[0096] As shown in FIG. 14, the second intermediate shaft 50B is provided along an axis O8 that is on a different axis from the second axle 37B and extends parallel to the axis O2 of the second axle 37B. As shown in FIG. 18, the second intermediate shaft 50B is rotatably provided about the axis O8 with respect to the second support member 36Ba via a bearing 51Ba. Further, the second intermediate shaft 50B is rotatably provided about the axis O8 with respect to the second swing support member 36Bb via a bearing 51Bb. The second intermediate shaft 50B is provided coaxially with the first intermediate shaft 50A and arranged side by side with the first intermediate shaft 50A along the axis O8. Therefore, the second swing support member 36Bb is attached to the second support member 36Ba fixed to the swivel shaft 35 via the second intermediate shaft 50B and is provided so as to be swingable about the axis O8. For this reason, the second axle 37B provided on the second swing support member 36Bb is provided so as to be swingable about the axis O8 integrally with the second swing support member 36Bb.

[0097] As shown in FIGS. 13 to 19, the rotational force transmission mechanism 13 includes a first rotational force transmission mechanism 13A and a second rotational force transmission mechanism 13B.

[0098] The first rotational force transmission mechanism 13A transmits the rotational force of the first drive unit 21A to the first input shaft 25A and transmits the rotational force of the first input shaft 25A to the first wheel 15A. The first rotational force transmission mechanism 13A includes a first drive gear 31A, a first driven gear 32A, a first connecting gear 33A, a first connecting output gear 34A, a first conversion gear 41A, a first conversion output gear 42A, and a first rotational force connection mechanism 16A. In the drive wheel 130 of the embodiment, the first drive gear 31A and the first driven gear 32A, and the first connecting gear 33A and the first connecting output gear 34A are constituted by spur gears, and the first conversion gear 41A and the first conversion output gear 42A are constituted by bevel gears.

[0099] In the first rotational force transmission mechanism 13A, as shown in FIG. 17, the first drive gear 31A is fixed to the first drive shaft 21Ac of the first drive unit 21A. Therefore, the first drive gear 31A rotates about the axis O6 of the first drive shaft 21Ac by the rotational force with which the first drive unit 21A is driven. The first driven gear 32A is fixed to the upper end portion of the first input shaft 25A. Therefore, the first driven gear 32A rotates about the axis O1 of the first input shaft 25A. The first connecting gear 33A is fixed to the lower end portion of the first input shaft 25A. Therefore, the first connecting gear 33A rotates integrally with the first driven gear 32A about the axis O1 of the first input shaft 25A. As shown in FIG. 18, the first connecting output gear 34A is fixed to the upper end portion of the first parallel output shaft 40A. Therefore, the first connecting output gear 34A rotates about the axis O3 of the first parallel output shaft 40A. The first conversion gear 41A is fixed to the lower end portion of the first parallel output shaft 40A. Therefore, the first conversion gear 41A rotates integrally with the first connecting output gear 34A about the axis O3 of the first parallel output shaft 40A. The first conversion output gear 42A is fixed to the first intermediate shaft 50A. Therefore, the first conversion output gear 42A rotates about the axis O8 of the first intermediate shaft 50A.

[0100] The first rotational force connection mechanism 16A is configured as a first winding transmission mechanism having a pair of first winding wheels 55A and an endless first winding transmission member 56A wound around each first winding wheel 55A. The pair of first winding wheels 55A are configured as pulleys, and the first winding transmission member 56A is configured as a timing belt. Or, the pair of first winding wheels 55A are configured as sprockets, and the first winding transmission member 56A is configured as a chain. As shown in FIG. 18, one of the first winding wheels 55A is fixed to the first intermediate shaft 50A. Therefore, one of the first winding wheels 55A rotates about the axis O8 of the first intermediate shaft 50A. As shown in FIG. 19, the other first winding wheel 55A is fixed to the first axle 37A. Therefore, the other first winding wheel 55A rotates about the axis O2 of the first axle 37A. Note that the first rotational force connection mechanism 16A is provided so as to be swingable about the axis O8 of the first intermediate shaft 50A integrally with the first swing support member 36Ab. Further, in the first rotational force connection mechanism 16A, the first swing support member 36Ab is connected to the pivot shaft 35 via the first elastic member 54A, so that the swing about the axis O8 is supported with an elastic force. The first elastic member 54A is composed of, for example, a coil spring that generates an elastic force and a damper that is inserted into the coil spring and absorbs the impact applied to the coil spring.

[0101] In the first rotational force transmission mechanism 13A, the first drive gear 31A meshes with the first driven gear 32A. The first connecting gear 33A meshes with the first connecting output gear 34A. The first conversion gear 41A meshes with the first conversion output gear 42A. The first rotational force connection mechanism 16A has the first winding transmission member 56A wound around each first winding wheel 55A in the front-rear direction X. Therefore, the first rotational force transmission mechanism 13A transmits the rotational force of the first drive unit 21A from the first drive gear 31A to the first driven gear 32A to apply a rotational force to the first input shaft 25A, and transmits the rotational force of the first input shaft 25A from the first connecting gear 33A to the first connecting output gear 34A to apply a rotational force to the first parallel output shaft 40A. Subsequently, the rotational force of the first parallel output shaft 40A is transmitted from the first conversion gear 41A to the first conversion output gear 42A to change the direction of rotation to the first intermediate shaft 50A, and the rotational force of the first intermediate shaft 50A is transmitted to the first axle 37A by the first rotational force connection mechanism 16A to apply a rotational force to the first wheel 15A.

[0102] The second rotational force transmission mechanism 13B transmits the rotational force of the second drive unit 21B to the first input shaft 25A and transmits the rotational force of the second input shaft 25B to the second wheel 15B. The second rotational force transmission mechanism 13B includes a second drive gear 31B, a second driven gear 32B, a second connecting gear 33B, a second connecting output gear 34B, a second conversion gear 41B, a second conversion output gear 42B, and a second rotational force connection mechanism 16B. In the drive wheel 130 of the embodiment, the second drive gear 31B and the second driven gear 32B, and the second connecting gear 33B and the second connecting output gear 34B are constituted by spur gears, and the second conversion gear 41B and the second conversion output gear 42B are constituted by bevel gears.

[0103] In the second rotational force transmission mechanism 13B, as shown in FIG. 17, the second drive gear 31B is fixed to the second drive shaft 21Bc of the second drive unit 21B. Therefore, the second drive gear 31B rotates about the axis O7 of the second drive shaft 21Bc by the rotational force with which the second drive unit 21B is driven. The second driven gear 32B is fixed to the upper end portion of the second input shaft 25B. Therefore, the second driven gear 32B rotates about the axis O1 of the second input shaft 25B. The second connecting gear 33B is fixed to the lower end portion of the second input shaft 25B. Therefore, the second connecting gear 33B rotates integrally with the second driven gear 32B about the axis O1 of the second input shaft 25B. As shown in FIG. 18, the second connecting output gear 34B is fixed to the upper end portion of the second parallel output shaft 40B. Therefore, the second connecting output gear 34B rotates about the axis O4 of the second parallel output shaft 40B. The second conversion gear 41B is fixed to the lower end portion of the second parallel output shaft 40B. Therefore, the second conversion gear 41B rotates integrally with the second connecting output gear 34B about the axis O4 of the second parallel output shaft 40B. The second conversion output gear 42B is fixed to the second intermediate shaft 50B. Therefore, the second conversion output gear 42B rotates about the axis O8 of the second intermediate shaft 50B.

[0104] The second rotational force connection mechanism 16B is configured as a second winding transmission mechanism having a pair of second winding wheels 55B and an endless second winding transmission member 56B wound around each second winding wheel 55B. The pair of second winding wheels 55B are configured as pulleys, and the second winding transmission member 56B is configured as a timing belt. Alternatively, the pair of second winding wheels 55B are configured as sprockets, and the second winding transmission member 56B is configured as a chain. As shown in FIG. 18, one of the second winding wheels 55B is fixed to the second intermediate shaft 50B. Accordingly, one of the second winding wheels 55B rotates about the axis O8 of the second intermediate shaft 50B. As shown in FIG. 19, the other second winding wheel 55B is fixed to the second axle 37B. Accordingly, the other second winding wheel 55B rotates about the axis O2 of the second axle 37B. Note that the second rotational force connection mechanism 16B is provided so as to be swingable about the axis O8 of the second intermediate shaft 50B integrally with the second swing support member 36Bb. Further, in the second rotational force connection mechanism 16B, the second swing support member 36Bb is connected to the pivot shaft 35 via the second elastic member 54B, so that the swing about the axis O8 is supported with an elastic force. The second elastic member 54B is composed of, for example, a coil spring that generates an elastic force and a damper that is inserted into the coil spring and absorbs the impact applied to the coil spring.

[0105] And in the second rotational force transmission mechanism 13B, the second driving gear 31B meshes with the second driven gear 32B. The second connecting gear 33B meshes with the second connecting output gear 34B. The second conversion gear 41B meshes with the second conversion output gear 42B. The second rotational force connection mechanism 16B has the second winding transmission member 56B wound around each second winding wheel 55B in the front-rear direction X. Therefore, the second rotational force transmission mechanism 13B transmits the rotational force of the second driving unit 21B from the second driving gear 31B to the second driven gear 32B to apply a rotational force to the second input shaft 25B, and transmits the rotational force of the second input shaft 25B from the second connecting gear 33B to the second connecting output gear 34B to apply a rotational force to the second parallel output shaft 40B. Subsequently, the rotational force of the second parallel output shaft 40B is transmitted from the second conversion gear 41B to the second conversion output gear 42B to convert the direction of rotation to the second intermediate shaft 50B, and the rotational force of the second intermediate shaft 50B is transmitted to the second axle 37B by the second rotational force connection mechanism 16B to apply a rotational force to the second wheel 15B.

[0106] Also, in the drive wheel 130 of the embodiment, the rotation axis O5 of the wheels (the first wheel 15A and the second wheel 15B) shown in FIG. 19 is offset (displaced) in the horizontal direction (front-rear direction X) perpendicular to the axis O1 of the turning shaft 35 as shown in FIG. 15. The rotation axis O5 of the wheels intersects the axes O2 of the respective axles 37A, 37B and extends along the vertical direction, and is a straight line passing through the center between the respective wheels 15A, 15B (the center between the points where the wheels 15A, 15B contact the ground) and parallel to the axis O1. Such a configuration in which the rotation axis O5 of the wheels (the first wheel 15A and the second wheel 15B) is offset (displaced) in the horizontal direction (front-rear direction X) perpendicular to the axis O1 of the turning shaft 35 is achieved in the drive wheel 130 of the embodiment by the first winding transmission member 56A being wound around each first winding wheel 55A in the front-rear direction X and the second winding transmission member 56B being wound around each second winding wheel 55B in the front-rear direction X in the first rotational force connection mechanism 16A and the second rotational force connection mechanism 16B.

[0107] This drive wheel 130 can rotate and steer each wheel 15A, 15B by rotating the first input shaft 25A and the second input shaft 25B by the drive mechanism 11. For example, by rotating the first input shaft 25A and the second input shaft 25B in opposite directions, rotating the first wheel 15A and the second wheel 15B in the same direction, and applying a rotational force to the first input shaft 25A and the second input shaft 25B so that the rotational speeds (rotation rates) of the first wheel 15A and the second wheel 15B are the same, each wheel 15A, 15B can be rotated without being steered. At this time, by making the rotational speeds (rotation rates) of the first wheel 15A and the second wheel 15B different, each wheel 15A, 15B can be steered in a rotating or stopped state.

[0108] Here, the operation of the drive wheel 130 will be described with reference to FIG. 20. In FIG. 20, for convenience, the wheels (the first wheel 15A and the second wheel 15B) are shown by unfolding them in the vertical direction. When the drive wheel 130 rotates the first input shaft 25A in the A1 direction, the first connecting gear 33A provided on the first input shaft 25A rotates in the same direction, and the first connecting output gear 34A meshing with the first connecting gear 33A rotates in the A2 direction opposite to the A1 direction. When the first connecting output gear 34A rotates in the A2 direction, the first conversion gear 41A provided integrally with the first connecting output gear 34A rotates in the same direction, and the first conversion output gear 42A meshing with the first conversion gear 41A rotates in the A3 direction which is a different direction. Then, in the first winding transmission member 16A, the other first winding wheel 55A rotates in the CA direction which is the same direction as the A3 direction, and rotates the first wheel 15A provided integrally with the other first winding wheel 55A in the same direction. On the other hand, when the drive wheel 130 rotates the second input shaft 25B in the B1 direction opposite to the A1 direction, the second connecting gear 33B provided on the second input shaft 25B rotates in the same direction, and the second connecting output gear 34B meshing with the second connecting gear 33B rotates in the B2 direction opposite to the B1 direction. When the second connecting output gear 34B rotates in the B2 direction, the second conversion gear 41B provided integrally with the second connecting output gear 34B rotates in the same direction, and the second conversion output gear 42B meshing with the second conversion gear 41B rotates in the B3 direction which is a different direction. Then, in the second winding transmission member 16B, the other second winding wheel 55B rotates in the CB direction which is the same direction as the B3 direction, and rotates the second wheel 15B provided integrally with the other second winding wheel 55B in the same direction.

[0109] At this time, when the drive wheel 130 reduces the rotational speed of the second input shaft 25B with respect to the rotational speed of the first input shaft 25A so as to reduce the rotational speed of the second wheel 15B with respect to the rotational speed of the first wheel 15A, the turning shaft 35 rotates by the difference in rotational speed between the first wheel 15A and the second wheel 15B, and the first wheel 15A and the second wheel 15B turn and steer while being used for traveling. Also, when the drive wheel 130 stops the rotation of the first input shaft 25A or the second input shaft 25B, the rotational speed input to the first wheel 15A or the rotational speed input to the second wheel 15B becomes 0, and the first wheel 15A and the second wheel 15B turn and steer without being used for traveling.

[0110] The drive wheel 130 of such an embodiment, similar to the drive wheel 110, includes a first input shaft 25A and a second input shaft 25B on the same axis, axles 37A, 37B provided intersecting the first input shaft 25A, a first wheel 15A and a second wheel 15B provided on the axles 37A, 37B, a swivel shaft 35 rotatably provided coaxially with the first input shaft 25A and the second input shaft 25B and supporting each wheel 15A, 15B so as to be swiveling via the axles 37A, 37B, a first rotational force transmission mechanism 13A for transmitting the rotational force of the first input shaft 25A to the first wheel 15A, and a second rotational force transmission mechanism 13B for transmitting a rotational force having the same speed as the first input shaft 25A but rotating in the opposite direction to the second input shaft 25B to the second wheel 15B in the same direction and at the same rotational speed as the first wheel 15A.

[0111] This drive wheel 130, similar to the drive wheel 110, has a differential type omnidirectional movement mechanism and can perform stable running while suppressing yawing.

[0112] Also, in this drive wheel 130, the first rotational force transmission mechanism 13A is composed of a first conversion gear 41A and a first conversion output gear 42A provided on axes (a first parallel output shaft 40A and a first intermediate shaft 50A) perpendicular to each other and meshing with each other, and the first conversion gear 41A and the first conversion output gear 42A are composed of bevel gears. The second rotational force transmission mechanism 13B is composed of a second conversion gear 41B and a second conversion output gear 42B provided on axes (a second parallel output shaft 40B and a second intermediate shaft 50B) perpendicular to each other and meshing with each other, and the second conversion gear 41B and the second conversion output gear 42B are composed of bevel gears.

[0113] This drive wheel 130, similar to the drive wheel 110, can also adopt a rotation transmission mechanism composed of bevel gears provided on intersecting axes and meshing with each other, has a differential type omnidirectional movement mechanism, and can perform stable running while suppressing yawing.

[0114] Further, in this drive wheel 130, a first intermediate shaft 50A provided parallel to the first axle 37A on a different axis from the first axle 37A, and a second intermediate shaft 50B provided parallel to the second axle 37B on a different axis from the second axle 37B and coaxially with the first intermediate shaft 50A are further included. The first rotational force transmission mechanism 13A includes a first rotational force connection mechanism 16A that transmits the rotational force of the first input shaft 25A to the first intermediate shaft 50A and transmits the rotational force from the first intermediate shaft 50A to the first wheel 15A. The second rotational force transmission mechanism 13B includes a second rotational force connection mechanism 16B that transmits the rotational force of the second input shaft 25B to the second intermediate shaft 50B and transmits the rotational force from the second intermediate shaft 50B to the second wheel 15B. The first intermediate shaft 50A and the first rotational force connection mechanism 16A, and the second intermediate shaft 50B and the second rotational force connection mechanism 16B are arranged with the rotational axis O5 of each wheel 37A, 37B shifted in the horizontal direction orthogonal to the axis O2 of each axle 37A, 37B with respect to the axis O1 of the swivel shaft 35.

[0115] Here, in the drive wheel 110 described above, since the rotational direction is converted from the axis O1 of the coaxial swivel shaft 35 to the output shaft 40 in the paths of the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B, different gears for converting the rotational direction had to be used in the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B. Usually, when considering the strength of the gears, the design is made according to the smaller gears, and the larger gears become over-specification, so it is desired to make the sizes of the gears the same as much as possible. In this regard, according to the drive wheel 130, in the path of the first rotational force transmission mechanism 13A, the rotational position is converted from the axis O1 of the swivel shaft 35 to the first parallel output shaft 40A, and further the rotational direction is converted from the first parallel output shaft 40A to the first intermediate shaft 50A to transmit the rotational force to the first wheel 15A of the first axle 37A. In the path of the second rotational force transmission mechanism 13B, the rotational position is changed from the axis O1 of the swivel shaft 35 to the second parallel output shaft 40B, and further the rotational direction is converted from the second parallel output shaft 40B to the second intermediate shaft 50B to transmit the rotational force to the second wheel 15B. Thereby, according to the drive wheel 130, the same gears for converting the rotational direction can be used in the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B, so that the strengths of the components can be matched and the components can be easily procured.

[0116] Moreover, according to this drive wheel 130, when each of the wheels 15A and 15B is not being driven, the wheels 15A and 15B can be passively swiveled by an external force acting in the horizontal direction. That is, the carriage 100 can be automatically driven and automatically steered, and an operator can manually drive and manually steer it.

[0117] Also, in this drive wheel 130, the first rotational force connection mechanism 16A is composed of a first winding transmission mechanism having a pair of winding carts 55A and an endless winding transmission member 56A wound around each winding cart 55A, and the second rotational force connection mechanism 16B is composed of a second winding transmission mechanism having a pair of winding carts 55B and an endless winding transmission member 56B wound around each winding cart 55B.

[0118] Although it is also possible to use a gear mechanism for the first rotational force connection mechanism 16A and the second rotational force connection mechanism 16B, in this case, three or more odd-numbered gears are required, which leads to an increase in size or an increase in the complexity of the structure due to the use of a larger number of gears, thus inhibiting the degree of freedom in arrangement. In this regard, according to this drive wheel 130, since it does not cause an increase in size or complexity, the degree of freedom in arrangement can be improved.

[0119] Also, in this drive wheel 130, a first elastic member 54A that swingably supports the first rotational force connection mechanism 16A about the first intermediate shaft 50A and supports the first rotational force connection mechanism 16A with an elastic force, and a second elastic member 54B that swingably supports the second rotational force connection mechanism 16B about the second intermediate shaft 50B and supports the second rotational force connection mechanism 16B with an elastic force are further included.

[0120] According to this drive wheel 130, the impact applied to each of the wheels 15A and 15B by the first elastic member 54A and the second elastic member 54B can be absorbed by the elastic force, and the running stability can be further improved.

[0121] Also, the carriage 100 of the embodiment includes the above-described drive wheel 130 and a carriage body 101 to which the drive wheel 130 is attached. Therefore, the carriage 100 can perform stable running while having a differential-type omnidirectional movement mechanism.

[0122] Incidentally, although not shown in the figures, in the drive wheel 130 of the embodiment, the first intermediate shaft 50A and the second intermediate shaft 50B are fixed to the first wheel 15A and the second wheel 15B respectively to form the first axle 37A and the second axle 37B, and by eliminating the first rotational force connection mechanism 16A and the second rotational force connection mechanism 16B, and the first elastic member 54A and the second elastic member 54B, the same operational effects as those of the drive wheel 110 described above can be obtained.

[0123] [Embodiment 4 of the drive wheel] FIG. 21 is a perspective view showing the configuration of the drive wheel of Embodiment 4. FIG. 22 is a schematic diagram showing the driving force transmission path of the drive wheel of Embodiment 4.

[0124] The drive wheel 140 of Embodiment 4 is mainly different from the drive wheel 110 described above in the configuration of the rotational force transmission mechanism 13, the configuration of the output shaft 40, and the configuration of the axle 37. Further, the drive wheel 140 of Embodiment 4 is different from the drive wheel 130 described above in that the first intermediate shaft 50A and the second intermediate shaft 50B are fixed to the first wheel 15A and the second wheel 15B respectively to form the first axle 37A and the second axle 37B, and the first rotational force connection mechanism 16A and the second rotational force connection mechanism 16B, and the first elastic member 54A and the second elastic member 54B are eliminated, and the first conversion gear 41A and the first conversion output gear 42A, and the second conversion gear 41B and the second conversion output gear 42B are different in that they are screw gears, and other configurations are the same. Therefore, in the following description of the drive wheel 140 of Embodiment 4, the same reference numerals are given to the equivalent parts of the drive wheels 110 and 130 described above, and the description thereof is omitted.

[0125] The output shaft includes a first parallel output shaft 40A and a second parallel output shaft 40B.

[0126] As shown in FIGS. 21 and 22, the first parallel output shaft 40A is provided parallel to the first input shaft 25A. As shown in FIG. 22, the first parallel output shaft 40A is provided on a shaft different from the first input shaft 25A and extends along an axis O3 parallel to the axis O1 of the first input shaft 25A (the second input shaft 25B and the turning shaft 35). The first parallel output shaft 40A is rotatably provided about the axis O3 via a bearing with respect to a support member 36 fixed to the turning shaft 35.

[0127] As shown in FIGS. 21 and 22, the second parallel output shaft 40B is provided parallel to the second input shaft 25B. As shown in FIG. 22, the second parallel output shaft 40B is provided on a shaft different from the second input shaft 25B and extends along an axis O4 parallel to the axis O1 of the second input shaft 25B (the first input shaft 25A and the turning shaft 35). The second parallel output shaft 40B is rotatably provided about the axis O4 via a bearing with respect to a support member 36 fixed to the turning shaft 35.

[0128] The axle includes a first axle 37A and a second axle 37B.

[0129] The first axle 37A is provided along an axis O2 that intersects (is orthogonal to) the axis O1 of the first input shaft 25A, the second input shaft 25B, and the turning shaft 35. The first axle 37A is rotatably provided about the axis O2 via a bearing with respect to the support member 36.

[0130] The second axle 37B is provided along an axis O2 that intersects (is orthogonal to) the axis O1 of the first input shaft 25A, the second input shaft 25B, and the turning shaft 35. The second axle 37B is rotatably provided about the axis O2 via a bearing with respect to the support member 36. The second axle 37B is provided coaxially with the first axle 37A and is provided side by side with the first axle 37A along the axis O2.

[0131] As shown in FIG. 21, the rotational force transmission mechanism 13 includes a first rotational force transmission mechanism 13A and a second rotational force transmission mechanism 13B.

[0132] The first rotational force transmission mechanism 13A transmits the rotational force of the first drive unit 21A to the first input shaft 25A and transmits the rotational force of the first input shaft 25A to the first wheel 15A. The first rotational force transmission mechanism 13A includes a first drive gear 31A, a first driven gear 32A, a first connecting gear 33A, a first connecting output gear 34A, a first conversion gear 41A, and a first conversion output gear 42A. In the drive wheel 140 of the embodiment, the first drive gear 31A and the first driven gear 32A, the first connecting gear 33A and the first connecting output gear 34A are constituted by spur gears, and the first conversion gear 41A and the first conversion output gear 42A are constituted by helical gears.

[0133] The second rotational force transmission mechanism 13B transmits the rotational force of the second drive unit 21B to the first input shaft 25A and transmits the rotational force of the second input shaft 25B to the second wheel 15B. The second rotational force transmission mechanism 13B includes a second drive gear 31B, a second driven gear 32B, a second connecting gear 33B, a second connecting output gear 34B, a second conversion gear 41B, and a second conversion output gear 42B. In the drive wheel 140 of the embodiment, the second drive gear 31B and the second driven gear 32B, the second connecting gear 33B and the second connecting output gear 34B are constituted by spur gears, and the second conversion gear 41B and the second conversion output gear 42B are constituted by helical gears.

[0134] Further, in the drive wheel 140 of the embodiment, the rotational axis centers of the wheels (the first wheel 15A and the second wheel 15B) are offset (displaced) in the horizontal direction (front-rear direction X) orthogonal to the axis of the turning axis 35. The rotational axis centers of the wheels intersect the axes of the respective axles 37A, 37B and extend along the vertical direction, and are straight lines passing through the center between the respective wheels 15A, 15B (the center between the points where the wheels 15A, 15B contact the ground) and parallel to the axis of the turning axis 35. In such a configuration where the rotational axis centers of the wheels (the first wheel 15A and the second wheel 15B) are offset (displaced) in the horizontal direction (front-rear direction X) orthogonal to the axis of the turning axis 35, in the drive wheel 140 of the embodiment, the first connecting gear 33A and the first connecting output gear 34A mesh with each other in the front-rear direction X, and the second conversion gear 41B and the second conversion output gear 42B mesh with each other in the front-rear direction X.

[0135] This drive wheel 140 can rotate the first input shaft 25A and the second input shaft 25B by the drive mechanism 11 to rotate and steer each of the wheels 15A, 15B. For example, by rotating the first input shaft 25A and the second input shaft 25B in opposite directions and rotating the first wheel 15A and the second wheel 15B in the same direction, and by applying a rotational force to the first input shaft 25A and the second input shaft 25B so that the rotational speeds of the first wheel 15A and the second wheel 15B are the same, the wheels 15A, 15B can be rotated without being steered. At this time, by making the rotational speeds of the first wheel 15A and the second wheel 15B different, the wheels 15A, 15B can be steered while rotating or stopped.

[0136] Here, the operation of the drive wheel 140 will be described with reference to FIG. 22. In FIG. 22, for the sake of convenience, the wheels (the first wheel 15A and the second wheel 15B) are shown by being developed in the vertical direction. When the drive wheel 140 rotates the first input shaft 25A in the A1 direction, the first connecting gear 33A provided on the first input shaft 25A rotates in the same direction, and the first connecting output gear 34A meshing with the first connecting gear 33A rotates in the A2 direction opposite to the A1 direction. When the first connecting output gear 34A rotates in the A2 direction, the first conversion gear 41A provided integrally with the first connecting output gear 34A rotates in the same direction, and the first conversion output gear 42A meshing with the first conversion gear 41A rotates in the CA direction in a different direction. Then, the drive wheel 140 rotates the first wheel 15A provided integrally with the first conversion output gear 42A in the CA direction. On the other hand, when the drive wheel 130 rotates the second input shaft 25B in the B1 direction opposite to the A1 direction, the second connecting gear 33B provided on the second input shaft 25B rotates in the same direction, and the second connecting output gear 34B meshing with the second connecting gear 33B rotates in the B2 direction opposite to the B1 direction. When the second connecting output gear 34B rotates in the B2 direction, the second conversion gear 41B provided integrally with the second connecting output gear 34B rotates in the same direction, and the second conversion output gear 42B meshing with the second conversion gear 41B rotates in the CB direction in a different direction. Then, the drive wheel 140 rotates the second wheel 15B provided integrally with the second conversion output gear 42B in the CB direction.

[0137] At this time, when the drive wheels 140 reduce the rotational speed of the second input shaft 25B with respect to the rotational speed of the first input shaft 25A so as to reduce the rotational speed of the second wheel 15B with respect to the rotational speed of the first wheel 15A, the turning shaft 35 rotates by the difference in rotational speed between the first wheel 15A and the second wheel 15B, and the first wheel 15A and the second wheel 15B turn and steer while being used for traveling. Further, when the drive wheels 130 stop the rotation of the first input shaft 25A or the second input shaft 25B, the rotational speed input to the first wheel 15A or the rotational speed input to the second wheel 15B becomes 0, and the first wheel 15A and the second wheel 15B turn and steer without being used for traveling.

[0138] The drive wheels 140 of such an embodiment are the same as the drive wheels 110, and include coaxial first input shaft 25A and second input shaft 25B, axles 37A and 37B provided intersecting the first input shaft 25A, first wheel 15A and second wheel 15B provided on the axles 37A and 37B, a turning shaft 35 rotatably provided coaxially with the first input shaft 25A and the second input shaft 25B and supporting each wheel 15A and 15B so as to be turnable via the axles 37A and 37B, a first rotational force transmission mechanism 13A for transmitting the rotational force of the first input shaft 25A to the first wheel 15A, and a second rotational force transmission mechanism 13B for transmitting a rotational force that rotates in the opposite direction to the first input shaft 25A and has the same speed as the first input shaft 25A to the second wheel 15B in the same direction and at the same rotational speed as the first wheel 15A.

[0139] This drive wheel 140 has a differential type omnidirectional movement mechanism like the drive wheel 110, and can perform stable traveling while suppressing yawing.

[0140] Further, in this drive wheel 140, a first parallel output shaft 40A provided parallel to the first input shaft 25A on a different axis from the first input shaft 25A and a second parallel output shaft 40B provided parallel to the second input shaft 25B on a different axis from the second input shaft 25B are further included. The first rotational force transmission mechanism 13A transmits the rotational force of the first input shaft 25A to the first wheel 15A via the first parallel output shaft 40A, and the second rotational force transmission mechanism 13B transmits the rotational force of the second input shaft 25B to the second wheel 15B via the second parallel output shaft 40B.

[0141] Here, since the drive wheels 110 described above convert the rotation direction from the axis O1 of the coaxial swivel shaft 35 to the output shaft 40 in the paths of the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B, different gears for converting the rotation direction had to be used in the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B. Usually, when considering the strength of the gears, the design is made according to the smaller gear, and the larger gear becomes over-specification. Therefore, it is desired to make the sizes of the gears the same as much as possible. In this regard, according to the drive wheel 140, in the path of the first rotational force transmission mechanism 13A, the rotational position is converted from the axis O1 of the swivel shaft 35 to the first parallel output shaft 40A, and further the rotation direction is converted from the first parallel output shaft 40A to the first axle 37A to transmit the rotational force to the first wheel 15A of the first axle 37A. In the path of the second rotational force transmission mechanism 13B, the rotational position is changed from the axis O1 of the swivel shaft 35 to the second parallel output shaft 40B, and further the rotation direction is converted from the second parallel output shaft 40B to the second axle 37B to transmit the rotational force to the second wheel 15B. Thus, according to the drive wheel 140, the same gears for converting the rotation direction can be used in the first rotational force transmission mechanism 13A and the second rotational force transmission mechanism 13B. Therefore, the strengths of the components can be matched, and the components can be easily procured.

[0142] Also, in this drive wheel 140, the rotational axes of the respective wheels 15A, 15B are displaced and arranged in a horizontal direction orthogonal to the axes of the respective axles 37A, 37B with respect to the axis of the swivel shaft 35.

[0143] According to this drive wheel 140, when the respective wheels 15A, 15B are not driven, the respective wheels 15A, 15B can be passively swiveled by an external force acting in the horizontal direction. That is, the carriage 100 can be automatically traveled and automatically steered, and an operator can manually travel and manually steer it.

[0144] Further, the carriage 100 of the embodiment includes the above-described drive wheel 140 and a carriage body 101 to which the drive wheel 140 is attached. Therefore, the carriage 100 can perform stable traveling while including a differential omnidirectional movement mechanism.

[0145] [Modification Example] In the drive wheels 110, 120, 130, and 140 described above, the gears described as spur gears may be composed of, for example, helical gears. Also, in the drive wheels 110, 120, 130, and 140 described above, the gears described as bevel gears or screw gears may be composed of, for example, worm gears, crown gears, or universal joints.

Explanation of Signs

[0146] 13A First rotational force transmission mechanism 13B Second rotational force transmission mechanism 15A First wheel 15B Second wheel 16A First rotational force connection mechanism (first winding transmission member) 16B Second rotational force connection mechanism (second winding transmission member) 25A First input shaft 25B Second input shaft 35 Swivel shaft 37 Axle 37A First axle 37B Second axle 40 Output shaft 40A Cross output shaft 40A First parallel output shaft 40B Parallel output shaft 40B Second parallel output shaft 50A First intermediate shaft 50B Second intermediate shaft 54A First elastic member 54B Second elastic member 100 Carriage 101 Carriage body 110, 120, 130, 140 Drive wheels

Claims

1. A first input shaft and a second input shaft on the same axis, an axle provided to intersect the first input shaft, a first wheel and a second wheel provided on the axle, a swivel shaft rotatably provided on the same axis as the first input shaft and the second input shaft and supporting each wheel so as to be swiveling via the axle, a first rotational force transmission mechanism for transmitting the rotational force of the first input shaft to the first wheel, a second rotational force transmission mechanism for transmitting a rotational force having the same speed as the first input shaft but rotating in the opposite direction to the first input shaft to the second wheel in the same direction and at the same rotational speed as the first wheel, comprising a drive wheel.

2. The first rotational force transmission mechanism is composed of a first conversion gear and a first conversion output gear provided on axes orthogonal to each other and meshing with each other, and the first conversion gear and the first conversion output gear are bevel gears, The second rotational force transmission mechanism is composed of a second conversion gear and a second conversion output gear provided on axes orthogonal to each other and meshing with each other, and the second conversion gear and the second conversion output gear are bevel gears, The drive wheel according to Claim 1.

3. Further comprising an output shaft provided to intersect the first input shaft and the second input shaft, The first rotational force transmission mechanism transmits the rotational force of the first input shaft to the first wheel as rotation around the output shaft, The second rotational force transmission mechanism transmits the rotational force of the second input shaft to the second wheel as rotation around the output shaft, The drive wheel according to Claim 1.

4. An intersecting output shaft that intersects the first input shaft and is provided parallel to the axle, A parallel output shaft that is parallel to the second input shaft and intersects the axle, further comprising The first rotational force transmission mechanism transmits the rotational force of the first input shaft to the first wheel as rotation around the intersecting output shaft, The second rotational force transmission mechanism transmits the rotational force of the second input shaft to the second wheel as rotation around the parallel output shaft, The drive wheel according to Claim 1.

5. A first parallel output shaft provided parallel to the first input shaft on a shaft different from the first input shaft, A second parallel output shaft provided parallel to the second input shaft on a shaft different from the second input shaft, further comprising The first rotational force transmission mechanism transmits the rotational force of the first input shaft to the first wheel via the first parallel output shaft, The second rotational force transmission mechanism transmits the rotational force of the second input shaft to the second wheel via the second parallel output shaft, The drive wheel according to Claim 1.

6. The rotational axis centers of the respective wheels are displaced and arranged in a horizontal direction orthogonal to the axis center of the respective axles with respect to the axis center of the swivel shaft. The drive wheel according to any one of claims 1 to 5.

7. A first intermediate shaft provided parallel to the axle on a different shaft from the axle; A second intermediate shaft provided parallel to the axle and coaxial with the first intermediate shaft on a different shaft from the axle; further comprising The first rotational force transmission mechanism includes a first rotational force connection mechanism that transmits the rotational force of the first input shaft to the first intermediate shaft and transmits the rotational force from the first intermediate shaft to the first wheel. The second rotational force transmission mechanism includes a second rotational force connection mechanism that transmits the rotational force of the second input shaft to the second intermediate shaft and transmits the rotational force from the second intermediate shaft to the second wheel. The first intermediate shaft and the first rotational force connection mechanism, and the second intermediate shaft and the second rotational force connection mechanism are arranged such that the rotational axis of each wheel is displaced in a horizontal direction perpendicular to the axis of each axle with respect to the axis of the turning axis. The drive wheel according to claim 1.

8. The first rotational force connection mechanism consists of a first winding transmission mechanism having a pair of winding wheels and an endless winding transmission member wound around each winding wheel. The second rotational force connection mechanism consists of a second winding transmission mechanism having a pair of winding wheels and an endless winding transmission member wound around each winding wheel. The drive wheel according to claim 7.

9. A first elastic member that supports the first rotational force connection mechanism with an elastic force by swingably providing the first rotational force connection mechanism about the first intermediate shaft; A second elastic member that supports the second rotational force connection mechanism with an elastic force by swingably providing the second rotational force connection mechanism about the second intermediate shaft; further comprising The drive wheel according to claim 7 or 8.

10. A drive wheel; A bogie body to which the drive wheel is attached; comprising The drive wheel A first input shaft and a second input shaft on the same axis; A first axle provided intersecting the first input shaft; A second axle provided intersecting the second input shaft and coaxial with the first axle; A first wheel provided on the first axle; A second wheel provided on the second axle; A turning shaft rotatably provided on the same axis as the first input shaft and the second input shaft and supporting each wheel via each axle so as to be turnable; A first rotational force transmission mechanism that transmits the rotational force of the first input shaft to the first wheel; A second rotational force transmission mechanism that transmits a rotational force having the same speed as the first input shaft but rotating in the opposite direction to the second wheel in the same direction and at the same rotational speed as the first wheel; including A bogie.

Images