Drive wheel and cart

Abstract

The present invention simplifies a configuration equipped with a differential omnidirectional movement mechanism, and reduces manufacturing costs. This drive wheel comprises: a first drive mechanism 22A including a first drive shaft 22Ac; a second drive mechanism 22B including a second drive shaft 22Bc; a first input shaft 25A and a second input shaft 25B on the same axis; a first output shaft 40A and a second output shaft 40B; a first transmission gear mechanism 13A for transmitting the rotational force of the first drive shaft to the first output shaft through the first input shaft; a second transmission gear mechanism 13B for transmitting the rotational force of the second drive shaft to the second output shaft through the second input shaft; an axle 37 to which a wheel 15 is fixed; a first conversion gear mechanism 14A for transmitting the rotational force of the first output shaft to the axle; a second conversion gear mechanism 14B for transmitting the rotational force of the second output shaft to the axle; and a turning shaft 35 for turning the wheel through the axle. The second transmission gear mechanism includes a gear that is fixed to the second input shaft and loosely fitted around the first input shaft.

Description

Drive wheels and bogies

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

[0002] Patent Document 1 discloses a drive wheel and a bogie using the drive wheel. The drive wheel includes a first input shaft and a second input shaft arranged coaxially, a first output shaft and a second output shaft arranged on separate axes, a first spur gear mechanism that transmits the rotational force of the first input shaft to the first output shaft, a second spur gear mechanism that transmits the rotational force of the second input shaft to the second output shaft, wheels connected to an axle, a turning shaft that rotatably supports the wheels via the axle, a first power conversion mechanism that transmits the rotational force of the first output shaft to one end of the axle, and a second power conversion mechanism that transmits the rotational force of the second output shaft to the other end of the axle.

[0003] Japanese Patent Application Laid-Open No. 2020-024033

[0004] The drive wheel described in Patent Document 1 includes a differential omnidirectional movement mechanism. It is desirable to simplify the basic configuration as much as possible while still including such a differential omnidirectional movement mechanism. The drive wheel described in Patent Document 1 has a three-layer structure consisting of a first input shaft, a cylindrical second input shaft, and a cylindrical pivot shaft, all stacked together. Therefore, to ensure smooth operation of each shaft, dimensional tolerances of each component must be strictly controlled, and the intricate interlocking of each component makes assembly time-consuming. For this reason, there is a concern that the drive wheel described in Patent Document 1 may increase manufacturing costs.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a drive wheel and a bogie that are equipped with a differential omnidirectional movement mechanism, have a simplified basic configuration, and can reduce manufacturing costs.

[0006] In order to achieve the above-mentioned object, one embodiment of the drive wheel of the present disclosure comprises a first drive mechanism having a first drive shaft, a second drive mechanism having a second drive shaft, coaxial first and second input shafts, an output shaft, a first transmission mechanism that transmits the rotational force of the first drive shaft to the output shaft via the first input shaft, a second transmission mechanism that transmits the rotational force of the second drive shaft to the output shaft via the second input shaft, a rotatable axle to which a wheel is fixed, a power conversion mechanism that transmits the rotational force of the output shaft to the axle, and a turning shaft that rotatably supports the wheel via the axle, and the second transmission mechanism includes a gear fixed to the second input shaft and loosely fitted around the first input shaft.

[0007] In a desirable aspect of the above-mentioned drive wheel, the first transmission mechanism includes a first transmission drive gear fixed to the first drive shaft, a first transmission main / driven gear fixed to the first input shaft and meshing with the first transmission drive gear, and a first transmission secondary driven gear fixed to the first input shaft for transmitting rotational force to the output shaft, and the second transmission mechanism includes a second transmission drive gear fixed to the second drive shaft, a second transmission main / driven gear fixed to the second input shaft and meshing with the second transmission drive gear, and a second transmission secondary driven gear fixed to the second input shaft integrally with the second transmission main / driven gear for transmitting rotational force to the output shaft.

[0008] In a preferred embodiment of the above-mentioned drive wheel, the output shaft includes a first output shaft and a second output shaft on separate axes, the first transmission mechanism transmits the rotational force of the first input shaft to the first output shaft, the second transmission mechanism transmits the rotational force of the second input shaft to the second output shaft, and the power conversion mechanism includes a first power conversion mechanism that transmits the rotational force of the first output shaft to one end of the axle, and a second power conversion mechanism that transmits the rotational force of the second output shaft to the other end of the axle.

[0009] In a preferred embodiment of the drive wheel, the first drive mechanism includes a first drive unit having the first drive shaft as an output shaft, and the second drive mechanism includes a second drive unit having the second drive shaft as an output shaft.

[0010] In a preferred embodiment of the drive wheel, the first drive mechanism applies a rotational force to the first drive shaft via a first belt mechanism, and the second drive mechanism applies a rotational force to the second drive shaft via a second belt mechanism.

[0011] In a preferred embodiment of the drive wheel, the drive wheel further comprises an angle detection shaft that is arranged coaxially with the first input shaft and the second input shaft, is fixed to the turning shaft, and has an angle detector connected thereto.

[0012] As a desirable aspect of the above-mentioned drive wheel, in the first transmission mechanism, the first transmission main driven gear has a smaller pitch circle diameter than the first transmission secondary driven gear, and in the second transmission mechanism, the second transmission main driven gear has a smaller pitch circle diameter than the second transmission secondary driven gear.

[0013] In a preferred embodiment of the drive wheel, the output shaft is single, and a first transmission output gear and a second transmission output gear are fixed coaxially to the output shaft, the first transmission mechanism has a rotation-reverse gear with which the first transmission secondary driven gear meshes, and the rotation-reverse gear meshes with the first transmission output gear, and the second transmission mechanism has the second transmission secondary driven gear meshing with the second transmission output gear.

[0014] In a preferred embodiment of the above-mentioned drive wheel, the output shaft includes a first output shaft and a second output shaft on separate axes, the first transmission mechanism integrally connects the first input shaft and the first output shaft, and the power conversion mechanism includes a first power conversion mechanism that transmits the rotational force of the first output shaft to a specified part of the axle, and a second power conversion mechanism that transmits the rotational force of the second output shaft to the specified part of the axle.

[0015] As a desirable aspect of the above-mentioned drive wheel, the first drive mechanism has the first drive shaft integrally connected to the first input shaft, and the second drive mechanism has a gear of the second transmission mechanism fixed to the second drive shaft.

[0016] In a preferred embodiment of the drive wheels, the rotational axis of the wheels, which intersects with the axis of the axle and runs along the vertical direction, is shifted horizontally from the axis of the pivot shaft in a direction perpendicular to the axis of the axle.

[0017] In order to achieve the above object, a bogie according to one aspect of the present disclosure includes any one of the drive wheels described above and a bogie body to which the drive wheel is attached.

[0018] According to the present disclosure, it is possible to simplify the basic configuration while providing a differential omnidirectional movement mechanism and reduce manufacturing costs.

[0019] FIG. 1 is a perspective view showing the basic configuration of a drive wheel of the first embodiment. FIG. 2 is a right side view showing the basic configuration of a drive wheel of the first embodiment. FIG. 3 is a cross-sectional view showing a drive system of a drive wheel of the first embodiment. FIG. 4 is a cross-sectional view showing a drive system of a drive wheel of the first embodiment. FIG. 5 is a plan view showing a drive system of a drive wheel of the first embodiment. FIG. 6 is a perspective view showing a drive system of a drive wheel of the first embodiment. FIG. 7 is a schematic diagram showing a drive force transmission path of a drive wheel of the first embodiment. FIG. 8 is a perspective view showing the basic configuration of a drive wheel of the second embodiment. FIG. 9 is a bottom view showing the basic configuration of a drive wheel of the second embodiment. FIG. 10 is a cross-sectional view showing a drive system of a drive wheel of the second embodiment. FIG. 11 is a schematic diagram showing a drive force transmission path of a drive wheel of the second embodiment. FIG. 12 is a cross-sectional view showing the basic configuration of a drive wheel of the third embodiment. FIG. 13 is a schematic diagram showing a drive force transmission path of a drive wheel of the third embodiment. FIG. 14 is a right side view showing a drive system of a drive wheel of the fourth embodiment. FIG. 15 is a cross-sectional view showing a drive system of a drive wheel of the fourth embodiment. FIG. 16 is a perspective view showing a drive system of a drive wheel of embodiment 4. FIG. 17 is a schematic diagram showing a drive force transmission path of a drive wheel of embodiment 4. FIG. 18 is a perspective view showing a basic configuration of a drive wheel of embodiment 5. FIG. 19 is a right side view showing a drive system of a drive wheel of embodiment 5. FIG. 20 is a perspective view showing a drive system of a drive wheel of embodiment 5. FIG. 21 is a schematic diagram showing a drive force transmission path of a drive wheel of embodiment 5. FIG. 22 is a perspective view showing a basic configuration of a drive wheel of embodiment 6. FIG. 23 is a cross-sectional view showing a drive system of a drive wheel of embodiment 6. FIG. 24 is a perspective view showing a drive system of a drive wheel of embodiment 6. FIG. 25 is a schematic diagram showing a drive force transmission path of a drive wheel of embodiment 6. FIG. 26 is a schematic diagram showing an example configuration of a bogie of an embodiment.

[0020] Preferred embodiments of the drive wheels and bogies according to the present disclosure will be described in detail below with reference to the drawings. Note that the present invention is not limited to these embodiments, and when there are multiple embodiments, the present invention also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range.

[0021] FIG. 26 is a schematic diagram illustrating an example of the configuration of a carriage according to an embodiment.

[0022] The trolley 100 includes a trolley body 101 , a handle portion 102 , four drive wheels 110 ( 120 , 130 , 140 , 150 , 160 ), a power supply portion 104 , and a control device 105 .

[0023] The bogie body 101 is, for example, a flat plate material and has a rectangular shape in a plan view. A handle portion 102 is fixed to one longitudinal side of the bogie body 101. Four drive wheels 110 are attached to the four corners of the back side of the bogie body 101. The four drive wheels 110 are rotatable and steerable. In addition, a power supply portion 104 and a control device 105 are attached to the back side of the bogie body 101 between the front and rear drive wheels 110. 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 RAM. Therefore, in the bogie 100, the control device 105 controls the drive wheels 110.

[0024] The cart body 101 has a flat surface, so that an object to be transported can be placed on the flat surface. That is, the cart 100 can be configured as an automatic guided vehicle (AGV). The cart 100 can also be configured as a device that travels by placing equipment along the flat surface of the cart body 101. Examples of such equipment include a hand lifter, a forklift, a picking robot, and medical equipment.

[0025] The bogie 100 and the equipment are not limited to the above-described configuration in terms of the number and arrangement of the drive wheels 110. For example, in the above-described four-wheel configuration, the bogie 100 and the equipment may have a pair of drive wheels 110 attached to the rear side of the bogie 100 and a pair of driven wheels attached to the front side of the bogie 100. Furthermore, although not explicitly shown in the drawings, in a configuration with three or more wheels, the bogie 100 and the equipment may have one drive wheel 110 and all the other wheels may be driven wheels. Furthermore, although not explicitly shown in the drawings, in a configuration with three or more wheels, the bogie 100 and the equipment may have no driven wheels and all the wheels may be drive wheels 110. In other words, in a configuration with three or more wheels, the bogie 100 and the equipment may have at least one drive wheel 110.

[0026] [First Embodiment of Drive Wheel] The drive wheel 110 will now be described in detail. FIG. 1 is a perspective view showing the basic configuration of the drive wheel of the first embodiment. FIG. 2 is a right side view showing the basic configuration of the drive wheel of the first embodiment. FIG. 3 is a cross-sectional view (cross-sectional view A-A in FIG. 2) showing the drive system of the drive wheel of the first embodiment. FIG. 4 is a cross-sectional view (cross-sectional view B-B in FIG. 2) showing the drive system of the drive wheel of the first embodiment. FIG. 5 is a plan view showing the drive system of the drive wheel of the first embodiment. FIG. 6 is a perspective view showing the drive system of the drive wheel of the first embodiment. FIG. 7 is a schematic diagram showing the drive force transmission path of the drive wheel of the first embodiment.

[0027] In the following description, of the first, second, and third directions that intersect with one another, the first direction will be referred to as the "front-rear direction X," the second direction will be referred to as the "width direction Y," and the third direction will be referred to as the "up-down direction Z." The front-rear direction X, width direction Y, and up-down direction Z are perpendicular to one another. The front-rear direction X typically corresponds to the direction along which the drive wheels 110 move straight.

[0028] The drive wheel 110 has a main body 10 fixed to the bogie body 101 of the bogie 100 as described above, and based on this main body 10, a drive mechanism 11, a swivel section 12, a transmission mechanism 13, a power conversion mechanism 14, and wheels 15 are provided.

[0029] The main body 10 is formed in a plate shape with its plate surfaces facing up and down (see FIGS. 3 and 4). The drive mechanism 11 inputs rotational force and is provided mainly above the main body 10. The swivel unit 12 is located mainly below the main body 10. The transmission mechanism 13 transmits the rotational force input by the drive mechanism 11. The power conversion mechanism 14 transmits the rotational force of the transmission mechanism 13 to the wheels 15. The wheels 15 are single wheels that are rotatable by the rotational force input via the drive mechanism 11, the transmission mechanism 13, and the power conversion mechanism 14, and are steerable by the swivel unit 12.

[0030] The drive mechanism 11 includes a first drive mechanism 22A and a second drive mechanism 22B.

[0031] The first drive mechanism 22A includes a first drive unit 22Aa, a first reducer 22Ab, and a first drive shaft 22Ac. The first drive unit 22Aa is configured as a motor. The first reducer 22Ab reduces the rotational speed output by the first drive unit 22Aa and is integrally connected to the first drive unit 22Aa. The first drive shaft 22Ac rotates in accordance with the output of the first reducer 22Ab. In the drive wheel 110 of this embodiment, the first drive shaft 22Ac is configured as a drive unit integral with the first drive unit 22Aa and the first reducer 22Ab. The first drive mechanism 22A is attached to the main body 10 so that the axis O6 (see FIG. 3) of the first drive shaft 22Ac extends along the vertical direction Z.

[0032] The second drive mechanism 22B includes a second drive unit 22Ba, a second reducer 22Bb, and a second drive shaft 22Bc. The second drive unit 22Ba is configured as a motor. The second reducer 22Bb reduces the rotational speed output by the second drive unit 22Ba and is integrally connected to the second drive unit 22Ba. The second drive shaft 22Bc rotates in accordance with the output of the second reducer 22Bb. In the drive wheel 110 of this embodiment, the second drive shaft 22Bc is configured as a drive unit integral with the second drive unit 22Ba and the second reducer 22Bb. The second drive mechanism 22B is attached to the main body 10 so that the axis O7 (see FIG. 3) of the second drive shaft 22Bc extends along the vertical direction Z.

[0033] The swivel unit 12 includes a swivel shaft 35, a first support member 36A, and a second support member 36B. The swivel shaft 35 has an axis O1 at the center of its disk shape and is rotatably supported via bearings 45 (see FIGS. 3 and 4 ) provided on the outer periphery of the main body 10. This allows the swivel shaft 35 to be rotatable relative to the main body 10 around the axis O1.

[0034] The revolving shaft 35 is disposed so as to penetrate the first input shaft 25A coaxially with the axis O1 in the vertical direction Z and rotatably supports it via a bearing 43b (see FIG. 3). The first input shaft 25A is rotatably supported coaxially with the axis O1 relative to the main body 10 via a bearing 43a (see FIG. 3). Therefore, the first input shaft 25A is supported rotatably relative to the revolving shaft 35 about the axis O1, and is also supported rotatably relative to the main body 10 about the axis O1. In other words, the revolving shaft 35 is rotatable relative to the main body 10 regardless of the rotation of the first input shaft 25A. Therefore, the drive wheel 110 of this embodiment can input a rotational force to the first input shaft 25A located on the axis O1, which is the rotation axis of the wheel 15.

[0035] The revolving shaft 35 positions the second input shaft 25B along the vertical direction Z. The second input shaft 25B passes through the first input shaft 25A and is rotatably disposed outside the first input shaft 25A via a bearing 44 (see FIG. 3 ). Therefore, the second input shaft 25B is supported via the first input shaft 25A for relative rotation about the axis O1 relative to the revolving shaft 35, and is also supported for relative rotation about the axis O1 relative to the main body 10. In other words, the revolving shaft 35 is rotatable relative to the main body 10 regardless of the rotation of the second input shaft 25B. Therefore, the drive wheel 110 of this embodiment can input rotational force to the second input shaft 25B, which is located on the axis O1, which is the rotation axis of the wheel 15. With this configuration, the first input shaft 25A, the second input shaft 25B, and the revolving shaft 35 are rotatably disposed coaxially along the axis O1.

[0036] A first support member 36A and a second support member 36B are provided below the pivot shaft 35 so as to extend downward on both sides of the wheel 15 in the width direction Y. The wheel 15 is integrally provided with an axle 37 that extends in the width direction Y along an axis O2 that is perpendicular to the direction in which the axis O1 extends (the up-down direction Z). One end of the axle 37 along the axis O2 is rotatably supported by the first support member 36A via a bearing 48 (see FIG. 4 ), and the other end is rotatably supported by the second support member 36B via a bearing 48.

[0037] The rotating shaft 35 is disposed so as to penetrate the first output shaft 40A in the vertical direction Z parallel to the axis O1, and rotatably supports the first output shaft 40A via bearings 46 (see FIG. 4). Therefore, the first output shaft 40A is supported so as to be rotatable relative to the rotating shaft 35 about an axis O3 parallel to the axis O1.

[0038] The rotating shaft 35 is disposed so as to penetrate the second output shaft 40B in the vertical direction Z parallel to the axis O1, and rotatably supports the second output shaft 40B via a bearing 47 (see FIG. 4). Therefore, the second output shaft 40B is supported so as to be rotatable relative to the rotating shaft 35 about an axis O4 parallel to the axis O1.

[0039] As shown in FIGS. 4 to 6, the transmission mechanism 13 has a first transmission gear mechanism (first transmission mechanism) 13A and a second transmission gear mechanism (second transmission mechanism) 13B.

[0040] The first transmission gear mechanism 13A transmits the rotational force of the first drive shaft 22Ac to the first output shaft 40A via the first input shaft 25A. The first transmission gear mechanism 13A includes a first transmission drive gear 31A, a first transmission main driven gear 32A, a first transmission secondary driven gear 33A, and a first transmission output gear 34A. In the driving wheel 110 of this embodiment, the first transmission drive gear 31A, the first transmission main driven gear 32A, the first transmission secondary driven gear 33A, and the first transmission output gear 34A are each configured as a spur gear.

[0041] In the first transmission gear mechanism 13A, the first transmission drive gear 31A is fixed to the first drive shaft 22Ac of the first drive mechanism 22A. Therefore, the first transmission drive gear 31A rotates around the axis O6 of the first drive shaft 22Ac by the rotational force of the first drive mechanism 22A. The first transmission main driven gear 32A and the first transmission secondary driven gear 33A are fixed to the first input shaft 25A. Therefore, the first transmission main driven gear 32A and the first transmission secondary driven gear 33A rotate around the axis O1 of the first input shaft 25A. The first transmission output gear 34A is fixed to the first output shaft 40A. Therefore, the first transmission output gear 34A rotates around the axis O3 of the first output shaft 40A. The first transmission drive gear 31A meshes with the first transmission main driven gear 32A. The first transmission secondary driven gear 33A meshes with the first transmission output gear 34A. Therefore, the first transmission gear mechanism 13A transmits the rotational force of the first drive mechanism 22A from the first transmission drive gear 31A to the first transmission main driven gear 32A, thereby giving rotational force to the first input shaft 25A, and further transmits the rotational force of the first input shaft 25A from the first transmission secondary driven gear 33A to the first transmission output gear 34A, thereby giving rotational force to the first output shaft 40A.

[0042] The second transmission gear mechanism 13B transmits the rotational force of the second drive shaft 22Bc to the second output shaft 40B via the second input shaft 25B. The second transmission gear mechanism 13B includes a second transmission drive gear 31B, a second transmission main driven gear 32B, a second transmission secondary driven gear 33B, and a second transmission output gear 34B. In the drive wheel 110 of this embodiment, the second transmission drive gear 31B, the second transmission main driven gear 32B, the second transmission secondary driven gear 33B, and the second transmission output gear 34B are each configured as a spur gear.

[0043] In the second transmission gear mechanism 13B, the second transmission drive gear 31B is fixed to the second drive shaft 22Bc of the second drive mechanism 22B. Therefore, the second transmission drive gear 31B rotates about the axis O7 of the second drive shaft 22Bc by the rotational force of the second drive mechanism 22B. The second transmission main driven gear 32B and the second transmission secondary driven gear 33B are fixed to the second input shaft 25B. Therefore, the second transmission main driven gear 32B and the second transmission secondary driven gear 33B are loosely fitted around the outer side of the first input shaft 25A via the second input shaft 25B with play, and rotate about the axis O1 of the second input shaft 25B. The second transmission main driven gear 32B and the second transmission secondary driven gear 33B are disposed between the first transmission main driven gear 32A and the first transmission secondary driven gear 33A of the first transmission gear mechanism 13A. The second transmission output gear 34B is fixed to the second output shaft 40B. Therefore, the second transmission output gear 34B rotates around the axis O4 of the second output shaft 40B. The second transmission drive gear 31B meshes with the second transmission main driven gear 32B. The second transmission secondary driven gear 33B meshes with the second transmission output gear 34B. Therefore, the second transmission gear mechanism 13B transmits the rotational force of the second drive mechanism 22B from the second transmission drive gear 31B to the second transmission main driven gear 32B to impart the rotational force to the second input shaft 25B, and further transmits the rotational force of the second input shaft 25B from the second transmission secondary driven gear 33B to the second transmission output gear 34B to impart the rotational force to the second output shaft 40B.

[0044] In this transmission mechanism 13, the first transmission drive gear 31A of the first transmission gear mechanism 13A and the second transmission drive gear 31B of the second transmission gear mechanism 13B have the same pitch circle diameter and the same number of teeth. Also, in the transmission mechanism 13, the first transmission main driven gear 32A and the first transmission secondary driven gear 33A of the first transmission gear mechanism 13A and the second transmission main driven gear 32B and the second transmission secondary driven gear 33B of the second transmission gear mechanism 13B have the same pitch circle diameter and the same number of teeth. Also, in the transmission mechanism 13, the first transmission output gear 34A of the first transmission gear mechanism 13A and the second transmission output gear 34B of the second transmission gear mechanism 13B have the same pitch circle diameter and the same number of teeth.

[0045] As shown in FIGS. 1 to 6, the power conversion mechanism 14 has a first conversion gear mechanism (first power conversion mechanism) 14A and a second conversion gear mechanism (second power conversion mechanism) 14B.

[0046] The first conversion gear mechanism 14A transmits the rotational force of the first output shaft 40A to the axle 37. The first conversion gear mechanism 14A is composed of a first conversion drive gear 41A and a first conversion driven gear 42A. In the driving wheel 110 of this embodiment, the first conversion gear mechanism 14A and the first conversion driven gear 42A are composed of bevel gears.

[0047] The first conversion drive gear 41A is fixed to the lower part of the first output shaft 40A. Therefore, the first conversion drive gear 41A rotates around the axis O3 together with the first output shaft 40A. Furthermore, the first conversion driven gear 42A is fixed to one end of the axle 37. Therefore, the first conversion driven gear 42A rotates around the axis O2 together with the axle 37. The first conversion drive gear 41A meshes with the first conversion driven gear 42A. Therefore, the first conversion gear mechanism 14A converts the rotation of the first output shaft 40A around the axis O3 into rotation of the axle 37 around the axis O2.

[0048] The second conversion gear mechanism 14B transmits the rotational force of the second output shaft 40B to the axle 37. The second conversion gear mechanism 14B is composed of a second conversion drive gear 41B and a second conversion driven gear 42B. In the driving wheel 110 of this embodiment, the second conversion gear mechanism 14B and the second conversion driven gear 42B are composed of bevel gears.

[0049] The second conversion drive gear 41B is fixed to the lower part of the second output shaft 40B. Therefore, the second conversion drive gear 41B rotates around the axis O4 together with the second output shaft 40B. Furthermore, the second conversion driven gear 42B is fixed to the other end of the axle 37. Therefore, the second conversion driven gear 42B rotates around the axis O2 together with the axle 37. The second conversion drive gear 41B meshes with the second conversion driven gear 42B. Therefore, the second conversion gear mechanism 14B converts the rotation of the second output shaft 40B around the axis O4 into rotation of the axle 37 around the axis O2.

[0050] 2 and 5, the drive wheel 110 of the embodiment is disposed such that the rotational axis O5 of the wheel 15, which is aligned in the vertical direction intersecting the axis O2 of the axle 37, is offset in the horizontal direction (front-rear direction X) perpendicular to the axis O2 of the axle 37 with respect to the axis O1 of the turning shaft 35. Furthermore, the drive wheel 110 of the embodiment is disposed such that the axis O3 of the first output shaft 40A and the axis O4 of the second output shaft 40B overlap the axis O2 of the axle 37 in a plan view.

[0051] The drive wheel 110 can rotate and steer the wheels 15 by rotating the first input shaft 25A and the second input shaft 25B using the drive mechanism 11. For example, by rotating the first input shaft 25A and rotating the second input shaft 25B in the opposite direction to the first input shaft 25A, and by making the number of rotations (rotational speed) transmitted to the first input shaft 25A and the second input shaft 25B the same, the wheels 15 can be rotated without being steered. In this case, by making the number of rotations (rotational speed) of the first input shaft 25A and the second input shaft 25B different, the wheels 15 can be steered while rotating or stopped.

[0052] Here, the operation of the drive wheel 110 will be described. As shown in Figure 7, when the first input shaft 25A of the drive wheel 110 rotates in the A1 direction, the first transmission main driven gear 32A and the first transmission secondary driven gear 33A rotate in the same direction, and the first transmission output gear 34A meshing with the first transmission secondary driven gear 33A rotates in the A2 direction, which is opposite to the A1 direction. When the first transmission output gear 34A rotates in the A2 direction, the first conversion drive gear 41A, which is integral with the first transmission output gear 34A via the first output shaft 40A, rotates in the same direction. Then, the first conversion driven gear 42A meshing with the first conversion drive gear 41A rotates in the A3 direction, causing the axle 37, which is integral with the first conversion driven gear 42A, to rotate in the same direction. On the other hand, when the second input shaft 25B rotates in the B1 direction, which is opposite to the A1 direction, the second transmission main driven gear 32B and the second transmission secondary driven gear 33B rotate in the same direction, and the second transmission output gear 34B meshing with the second transmission secondary driven gear 33B rotates in the B2 direction, which is opposite to the B1 direction. When the second transmission output gear 34B rotates in the B2 direction, the second conversion drive gear 41B, which is integral with the second transmission output gear 34B via the second output shaft 40B, rotates in the same direction. Then, the second conversion driven gear 42B meshing with the second conversion drive gear 41B rotates in the B3 direction, causing the axle 37, which is integral with the second conversion driven gear 42B, to rotate in the same direction.

[0053] At this time, when the rotation speed of the second input shaft 25B is reduced relative to the rotation speed of the first input shaft 25A, the rotation speed input to the second transmission main driven gear 32B and the second transmission secondary driven gear 33B of the drive wheel 110 becomes lower than the rotation speed input to the first transmission main driven gear 32A and the first transmission secondary driven gear 33A. Then, the turning shaft 35 rotates by the rotation speed difference, and the wheel 15 turns and is steered. Also, when the rotation of the first input shaft 25A or the second input shaft 25B is stopped, the rotation speed input to the first transmission main driven gear 32A and the first transmission secondary driven gear 33A or the rotation speed input to the second transmission main driven gear 32B and the second transmission secondary driven gear 33B becomes zero, and the wheel 15 turns and is steered without rotating.

[0054] The drive wheel 110 of the embodiment includes a first drive mechanism 22A having a first drive shaft 22Ac, a second drive mechanism 22B having a second drive shaft 22Bc, a first input shaft 25A and a second input shaft 25B on the same axis, an output shaft (a first output shaft 40A and a second output shaft 40B on separate axes), a first transmission gear mechanism (first transmission mechanism) 13A that transmits the rotational force of the first drive shaft 22Ac to the output shaft via the first input shaft 25A, a second transmission gear mechanism (second transmission mechanism) 13B that transmits the rotational force of the second drive shaft 22Bc to the output shaft via the second input shaft 25B, a rotatable axle 37 to which the wheel 15 is fixed, a power conversion mechanism 14 (first conversion gear mechanism (first power conversion mechanism) 14A, second conversion gear mechanism (second power conversion mechanism) 14B) that transmits the rotational force of the output shaft to the axle 37, and a turning shaft 35 that rotatably supports the wheel 15 via the axle 37. Furthermore, the drive wheel 110 includes a second transmission mechanism 13B that includes gears (second transmission main driven gear 32B and second transmission secondary driven gear 33B) that are fixed to the second input shaft 25B and loosely fitted to the first input shaft 25A.

[0055] The drive wheel 110 has a differential omnidirectional movement mechanism. That is, in the drive wheel 110, the rotational force of the first input shaft 25A is transmitted to the output shaft (first output shaft 40A) via the first transmission gear mechanism 13A, the rotational force of the second input shaft 25B is transmitted to the output shaft (second output shaft 40B) via the second transmission gear mechanism 13B, the rotational force is transmitted from the output shaft (first output shaft 40A) to the axle 37 via the power conversion mechanism 14 (first conversion gear mechanism 14A), and the rotational force is transmitted from the output shaft (second output shaft 40B) to the axle 37 via the power conversion mechanism 14 (second conversion gear mechanism 14B). The drive wheel 110 can switch between the rotation of the wheels 15 connected to the axle 37 and the steering of the wheels 15 by adjusting the rotation speeds of the first input shaft 25A and the second input shaft 25B.

[0056] In particular, in the drive wheel 110, in the second transmission gear mechanism 13B, gears (second transmission main driven gear 32B and second transmission secondary driven gear 33B) are fixed to the second input shaft 25B and loosely fitted to the first input shaft 25A. As a result, the drive wheel 110 of the embodiment does not require the three-layer structure of the conventional drive wheel 110 (for example, Patent Document 1), and the basic configuration can be simplified. Moreover, the drive wheel 110 makes it easy to manage the dimensional tolerances of each part to ensure smooth gear operation, and further, assembly can be facilitated by preventing the parts from becoming complicatedly intertwined. Therefore, the drive wheel 110 of the embodiment can reduce manufacturing costs.

[0057] In the drive wheel 110, the second transmission gear mechanism 13B includes a second transmission drive gear 31B fixed to the second drive shaft 22Bc, a second transmission main driven gear 32B fixed to the second input shaft 25B and meshing with the second transmission drive gear 31B, and a second transmission sub driven gear 33B fixed to the second input shaft 25B integrally with the second transmission main driven gear 32B and for transmitting rotational force to the output shaft (second output shaft 40B). Furthermore, in the drive wheel 110, the first transmission gear mechanism 13A includes a first transmission drive gear 31A fixed to the first drive shaft 22Ac, a first transmission main driven gear 32A fixed to the first input shaft 25A and meshing with the first transmission drive gear 31A, and a first transmission sub driven gear 33A fixed to the first input shaft 25A and for transmitting rotational force to the output shaft (first output shaft 40A).

[0058] In this drive wheel 110, the second transmission main driven gear 32B and the second transmission secondary driven gear 33B are fixed integrally to the second input shaft 25B in the second transmission gear mechanism 13B. As a result, the basic configuration of the drive wheel 110 of this embodiment can be simplified. Moreover, according to this drive wheel 110, the first transmission main driven gear 32A and the first transmission secondary driven gear 33A are fixed integrally to the first input shaft 25A in the first transmission gear mechanism 13A. As a result, the basic configuration of the drive wheel 110 of this embodiment can be further simplified.

[0059] In addition, in this drive wheel 110, the output shaft includes a first output shaft 40A and a second output shaft 40B on separate axes, a first transmission gear mechanism 13A transmits the rotational force of the first input shaft 25A to the first output shaft 40A, a second transmission gear mechanism 13B transmits the rotational force of the second input shaft 25B to the second output shaft 40B, and the power conversion mechanism 14 includes a first conversion gear mechanism (first power conversion mechanism) 14A that transmits the rotational force of the first output shaft 40A to one end of the axle 37, and a second conversion gear mechanism (second power conversion mechanism) 14B that transmits the rotational force of the second output shaft 40B to the other end of the axle 37.

[0060] According to this drive wheel 110, the rotational forces of the first output shaft 40A and the second output shaft 40B are transmitted to one end and the other end of the axle 37, respectively. Therefore, this drive wheel 110 can increase the transmission capacity to the axle 37 while simplifying the basic configuration.

[0061] In addition, in this drive wheel 110, the first drive mechanism 22A is configured integrally with the first drive shaft 22Ac, and the second drive mechanism 22B is configured integrally with the second drive shaft 22Bc.

[0062] According to this drive wheel 110, the first drive mechanism 22A is integral with the first drive shaft 22Ac, and the second drive mechanism 22B is integral with the second drive shaft 22Bc, so that the basic configuration can be simplified.

[0063] In addition, in this drive wheel 110, the rotation axis O5 of the wheel 15, which intersects the axis O2 of the axle 37 and runs vertically, is positioned offset horizontally from the axis O1 of the turning shaft 35, perpendicular to the axis O2 of the axle 37.

[0064] With this drive wheel 110, when the wheel 15 is not driven, the wheel 15 can passively turn by an external force acting from the horizontal direction. In other words, the cart 100 can be automatically driven and steered, and can also be manually driven and steered by an operator.

[0065] Moreover, the bogie 100 of the embodiment includes the above-described drive wheels 110 and the bogie body 101 to which the drive wheels 110 are attached. Therefore, the basic structure of the bogie 100 can be simplified.

[0066] [Embodiment 2 of Drive Wheel] Fig. 8 is a perspective view showing the basic configuration of a drive wheel of embodiment 2. Fig. 9 is a bottom view showing the basic configuration of a drive wheel of embodiment 2. Fig. 10 is a cross-sectional view (cross-sectional view taken along CC in Fig. 9) showing the drive system of the drive wheel of embodiment 2. Fig. 11 is a schematic diagram showing the drive force transmission path of the drive wheel of embodiment 2.

[0067] The driving wheel 120 of the second embodiment differs from the driving wheel 110 of the first embodiment described above mainly in the configuration of the driving mechanism 11. In the following description of the driving wheel 120 of the second embodiment, parts equivalent to those of the driving wheel 110 described above are denoted by the same reference numerals, and description thereof will be omitted.

[0068] The drive mechanism 11 includes a first drive mechanism 22A and a second drive mechanism 22B.

[0069] The first drive mechanism 22A includes a first drive unit 22Aa, a first reducer 22Ab, and a first drive shaft 22Ac. The first drive unit 22Aa and the first reducer 22Ab are integrally configured and fixed to the lower part of the main body 10. The first drive mechanism 22A also includes a first belt mechanism 23A, which applies a rotational force to the first drive shaft 22Ac via the first belt mechanism 23A. The first belt mechanism 23A includes a first drive pulley 23Aa provided at the output part of the first reducer 22Ab, a first driven pulley 23Ab fixed to the first drive shaft 22Ac, and a first drive belt 23Ac. The first drive shaft 22Ac is rotatably supported by the main body 10 via a bearing 51 (see FIG. 10 ). Therefore, in the first belt mechanism 23A, the first drive pulley 23Aa rotates in accordance with the output of the first reducer 22Ab, and the rotational force of the first drive pulley 23Aa is transmitted to the first driven pulley 23Ab via the first drive belt 23Ac, thereby rotating the first drive shaft 22Ac. In this embodiment, the pulley ratio between the first drive pulley 23Aa and the first driven pulley 23Ab is set to 1:1.

[0070] The second drive mechanism 22B includes a second drive unit 22Ba, a second reducer 22Bb, and a second drive shaft 22Bc. The second drive unit 22Ba and the second reducer 22Bb are integrally configured and fixed to the lower part of the main body 10. The second drive mechanism 22B also includes a second belt mechanism 23B, which applies a rotational force to the second drive shaft 22Bc via the second belt mechanism 23B. The second belt mechanism 23B includes a second drive pulley 23Ba provided at the output part of the second reducer 22Bb, a second driven pulley 23Bb fixed to the second drive shaft 22Bc, and a second drive belt 23Bc. The second drive shaft 22Bc is rotatably supported by the main body 10 via a bearing 52 (see FIG. 10 ). Therefore, in the second belt mechanism 23B, the second drive pulley 23Ba rotates in accordance with the output of the second reducer 22Bb, and the rotational force of the second drive pulley 23Ba is transmitted to the second driven pulley 23Bb via the second drive belt 23Bc, causing the second drive shaft 22Bc to rotate. In this embodiment, the pulley ratio between the second drive pulley 23Ba and the second driven pulley 23Bb is set to 1:1.

[0071] As shown in FIG. 11, the drive wheel 120 and the bogie 100 can operate in the same manner as the drive wheel 110 and the bogie 100 of the first embodiment, and can obtain the same effects as the drive wheel 110 and the bogie 100.

[0072] In particular, in the drive wheel 120, the first drive mechanism 22A applies a rotational force to the first drive shaft 22Ac via the first belt mechanism 23A, and the second drive mechanism 22B applies a rotational force to the second drive shaft 22Bc via the second belt mechanism 23B.

[0073] According to this drive wheel 120, by applying the first belt mechanism 23A and the second belt mechanism 23B, it is possible to provide flexibility in the arrangement of the first drive unit 22Aa and the first reducer 22Ab, and the second drive unit 22Ba and the second reducer 22Bb, which are the main components of the first drive mechanism 22A and the second drive mechanism 22B. Specifically, this drive wheel 120 allows the main components of the first drive mechanism 22A and the second drive mechanism 22B to be arranged below the main body 10 along with other components (the power conversion mechanism 14, the wheels 15, the pivot shaft 35, and the axle 37). As a result, the overall height of this drive wheel 120 can be reduced. Furthermore, with this drive wheel 120, the pulley ratio between the first drive pulley 23Aa and the first driven pulley 23Ab and the pulley ratio between the second drive pulley 23Ba and the second driven pulley 23Bb in the first belt mechanism 23A and the second belt mechanism 23B can be changed from 1:1 to another value, thereby allowing the drive wheel 120 to fulfill the role of a reduction mechanism.

[0074] Moreover, the bogie 100 of the embodiment includes the above-described drive wheels 120 and the bogie body 101 to which the drive wheels 120 are attached. Therefore, the basic structure of the bogie 100 can be simplified.

[0075] [Embodiment 3 of the driving wheel] Fig. 12 is a cross-sectional view (corresponding to the cross-sectional position A-A in Fig. 2) showing the basic configuration of a driving wheel of embodiment 3. Fig. 13 is a schematic diagram showing the driving force transmission path of the driving wheel of embodiment 2.

[0076] The driving wheel 130 of the third embodiment differs from the driving wheel 110 described above in that an angle detector 50 is applied. In the following description of the driving wheel 130 of the third embodiment, the same parts as those of the driving wheel 110 described above are denoted by the same reference numerals, and the description thereof will be omitted.

[0077] The drive wheel 130 has an angle detection shaft 50A that is arranged coaxially with the first input shaft 25A and the second input shaft 25B. The angle detection shaft 50A is rotatably inserted through the first input shaft 25A, has a lower portion fixed to the revolving shaft 35, and an upper portion that penetrates the main body 10 and protrudes upward. Therefore, the angle detection shaft 50A is rotatable together with the revolving shaft 35 regardless of the main body 10.

[0078] The angle detector 50 is fixed to the main body 10 and detects the rotation of the angle detection shaft 50A fixed to the swivel shaft 35. Therefore, the angle detector 50 detects the relative rotation angle between the main body 10 and the swivel shaft 35. In the drive wheel 130, the detection signal of the angle detector 50 is input to the control device 105 of the bogie (equipment) 100. As a result, the control device 105 can control the rotation of the drive wheel 130.

[0079] As shown in FIG. 13, the drive wheel 130 and the bogie 100 can operate in the same manner as the drive wheel 110 and the bogie 100 of the first embodiment, and can obtain the same effects as the drive wheel 110 and the bogie 100.

[0080] [Fourth embodiment of drive wheels] Fig. 14 is a right side view showing a drive system of a drive wheel of a fourth embodiment. Fig. 15 is a cross-sectional view (corresponding to the cross-sectional position A-A in Fig. 2) showing a drive system of a drive wheel of a fourth embodiment. Fig. 16 is a perspective view showing a drive system of a drive wheel of a fourth embodiment. Fig. 17 is a schematic diagram showing a drive force transmission path of a drive wheel of a fourth embodiment.

[0081] The drive wheel 140 of the fourth embodiment differs from the drive wheel 110 described above in the configuration of the transmission mechanism 13. In the following description of the drive wheel 140 of the fourth embodiment, parts equivalent to those of the drive wheel 110 described above are denoted by the same reference numerals, and description thereof will be omitted.

[0082] The transmission mechanism 13 has a first transmission gear mechanism (first transmission mechanism) 13A and a second transmission gear mechanism (second transmission mechanism) 13B.

[0083] The first transmission gear mechanism 13A transmits the rotational force of the first drive shaft 22Ac to the first output shaft 40A via the first input shaft 25A. The first transmission gear mechanism 13A includes a first transmission drive gear 31A, a first transmission main driven gear 32A, a first transmission sub driven gear 33A, and a first transmission output gear 34A.

[0084] In the first transmission gear mechanism 13A of the drive wheel 140, the first transmission main driven gear 32A has a smaller pitch circle diameter than the first transmission sub driven gear 33A. Therefore, the first transmission drive gear 31A that meshes with the first transmission main driven gear 32A is disposed closer to the axis O1 together with the first drive shaft 22Ac (first drive mechanism 22A) than the drive wheel 110.

[0085] The second transmission gear mechanism 13B transmits the rotational force of the second drive shaft 22Bc to the second output shaft 40B via the second input shaft 25B. The second transmission gear mechanism 13B includes a second transmission drive gear 31B, a second transmission main driven gear 32B, a second transmission sub driven gear 33B, and a second transmission output gear 34B.

[0086] In the second transmission gear mechanism 13B of the drive wheel 140, the second transmission main driven gear 32B has a smaller pitch circle diameter than the second transmission sub driven gear 33B. Therefore, the second transmission drive gear 31B that meshes with the second transmission main driven gear 32B is disposed closer to the axis O1 together with the second drive shaft 22Bc (second drive mechanism 22B) than the drive wheel 110.

[0087] In this drive wheel 140, the first transmission gear mechanism 13A has a first transmission main driven gear 32A with a smaller pitch circle diameter than the first transmission secondary driven gear 33A, and the second transmission gear mechanism 13B has a second transmission main driven gear 32B with a smaller pitch circle diameter than the second transmission secondary driven gear 33B.

[0088] According to this drive wheel 140, by reducing the pitch circle diameters of the first transmission main driven gear 32A and the second transmission main driven gear 32B, it is possible to use a bearing 44 with a relatively small diameter, thereby reducing manufacturing costs. Furthermore, according to this drive wheel 140, by reducing the pitch circle diameters of the first transmission main driven gear 32A and the second transmission main driven gear 32B, it is possible to improve the layout efficiency of the drive mechanism 11.

[0089] As shown in FIG. 17, the drive wheel 140 and the bogie 100 can operate in the same manner as the drive wheel 110 and the bogie 100 of the first embodiment, and can obtain the same effects as the drive wheel 110 and the bogie 100.

[0090] [Embodiment 5 of Drive Wheel] Fig. 18 is a perspective view showing the basic configuration of a drive wheel of embodiment 5. Fig. 19 is a right side view showing the drive system of the drive wheel of embodiment 5. Fig. 20 is a perspective view showing the drive system of the drive wheel of embodiment 5. Fig. 21 is a schematic diagram showing the drive force transmission path of the drive wheel of embodiment 5.

[0091] The drive wheel 150 of the fifth embodiment differs from the drive wheel 110 described above in the configurations of the transmission mechanism 13 and the power conversion mechanism 14. In the following description of the drive wheel 150 of the fifth embodiment, parts equivalent to those of the drive wheel 110 described above are denoted by the same reference numerals, and description thereof will be omitted.

[0092] The transmission mechanism 13 has a first transmission gear mechanism (first transmission mechanism) 13A and a second transmission gear mechanism (second transmission mechanism) 13B.

[0093] The first transmission gear mechanism 13A transmits the rotational force of the first drive shaft 22Ac to the first output shaft 40A via the first input shaft 25A. The first transmission gear mechanism 13A includes a first transmission drive gear 31A, a first transmission main driven gear 32A, a first transmission secondary driven gear 33A, a counter-rotating gear 33Aa, and a first transmission output gear 34A. In the drive wheel 150, the first transmission drive gear 31A, the first transmission main driven gear 32A, the first transmission secondary driven gear 33A, the counter-rotating gear 33Aa, and the first transmission output gear 34A are each composed of a spur gear.

[0094] In the first transmission gear mechanism 13A, the first transmission drive gear 31A is fixed to the first drive shaft 22Ac of the first drive mechanism 22A and rotates around the axis O6 of the first drive shaft 22Ac by the rotational force of the first drive mechanism 22A. The first transmission main driven gear 32A and the first transmission secondary driven gear 33A are fixed to the first input shaft 25A and rotate around the axis O1 of the first input shaft 25A. The counter-rotating gear 33Aa is supported on the pivot shaft 35 via a bearing (not shown) so as to be rotatable around an axis O8 parallel to the axes O1 and O3. The first transmission output gear 34A is fixed to the first output shaft 40A and rotates around the axis O3 of the first output shaft 40A. The first transmission drive gear 31A meshes with the first transmission main driven gear 32A. The first transmission secondary driven gear 33A meshes with the counter-rotating gear 33Aa. The counter-rotating gear 33Aa meshes with the first transmission output gear 34A. Therefore, the first transmission gear mechanism 13A transmits the rotational force of the first drive mechanism 22A from the first transmission drive gear 31A to the first transmission main driven gear 32A to impart the rotational force to the first input shaft 25A, and further transmits the rotational force of the first input shaft 25A from the first transmission sub driven gear 33A in a reversed direction by the counter-rotating gear 33Aa to the first transmission output gear 34A to impart the rotational force to the first output shaft 40A.

[0095] The second transmission gear mechanism 13B transmits the rotational force of the second drive shaft 22Bc to the first output shaft 40A via the second input shaft 25B. Here, in the drive wheel 150, the output shaft is the single first output shaft 40A, and there is no second output shaft. The second transmission gear mechanism 13B includes a second transmission drive gear 31B, a second transmission main driven gear 32B, a second transmission secondary driven gear 33B, and a second transmission output gear 34B. In the drive wheel 150 of this embodiment, the second transmission drive gear 31B, the second transmission main driven gear 32B, the second transmission secondary driven gear 33B, and the second transmission output gear 34B are each composed of spur gears.

[0096] In the second transmission gear mechanism 13B, the second transmission drive gear 31B is fixed to the second drive shaft 22Bc of the second drive mechanism 22B and rotates about the axis O7 of the second drive shaft 22Bc by the rotational force of the second drive mechanism 22B. The second transmission main driven gear 32B and the second transmission secondary driven gear 33B are fixed to the second input shaft 25B and rotate about the axis O1 of the second input shaft 25B. The second transmission main driven gear 32B and the second transmission secondary driven gear 33B are disposed between the first transmission main driven gear 32A and the first transmission secondary driven gear 33A of the first transmission gear mechanism 13A. The second transmission output gear 34B is fixed to the first output shaft 40A and rotates about the axis O3 of the first output shaft 40A. The second transmission drive gear 31B meshes with the second transmission main driven gear 32B. The second transmission secondary driven gear 33B meshes with the second transmission output gear 34B. Therefore, the second transmission gear mechanism 13B transmits the rotational force of the second drive mechanism 22B from the second transmission drive gear 31B to the second transmission main driven gear 32B to impart the rotational force to the second input shaft 25B, and further transmits the rotational force of the second input shaft 25B from the second transmission secondary driven gear 33B to the second transmission output gear 34B to impart the rotational force to the first output shaft 40A.

[0097] The power conversion mechanism 14 has a first conversion gear mechanism (first power conversion mechanism) 14A. The first conversion gear mechanism 14A is composed of a first conversion drive gear 41A and a first conversion driven gear 42A. The driving wheel 150 does not have a second conversion gear mechanism (second power conversion mechanism). The driving wheel 150 has the first conversion gear mechanism 14A composed of a cross gear.

[0098] The first conversion drive gear 41A is fixed to the lower part of the first output shaft 40A. Therefore, the first conversion drive gear 41A rotates around the axis O3 together with the first output shaft 40A. Furthermore, the first conversion driven gear 42A is fixed to one end of the axle 37. Therefore, the first conversion driven gear 42A rotates around the axis O2 together with the axle 37. The first conversion drive gear 41A meshes with the first conversion driven gear 42A. Therefore, the first conversion gear mechanism 14A converts the rotation of the first output shaft 40A around the axis O3 into rotation of the axle 37 around the axis O2.

[0099] Here, the operation of the drive wheel 150 will be described. As shown in FIG. 21 , when the first input shaft 25A of the drive wheel 150 rotates in the A1 direction, the first transmission main driven gear 32A and the first transmission secondary driven gear 33A rotate in the same direction, and the rotation-reversing gear 33Aa meshing with the first transmission secondary driven gear 33A rotates in the A2 direction, which is opposite to the A1 direction. When the rotation-reversing gear 33Aa rotates in the A2 direction, the first transmission output gear 34A meshing with the rotation-reversing gear 33Aa rotates in the C direction, which is opposite to the A2 direction. When the first transmission output gear 34A rotates in the C direction, the first conversion drive gear 41A, which is integral with the first transmission output gear 34A via the first output shaft 40A, rotates in the same direction. Then, the first conversion driven gear 42A meshing with the first conversion drive gear 41A rotates in the D direction, causing the axle 37, which is integral with the first conversion driven gear 42A, to rotate in the same direction. On the other hand, when the second input shaft 25B of the drive wheel 150 rotates in the B1 direction, which is opposite to the A1 direction, the second transmission main driven gear 32B and the second transmission secondary driven gear 33B rotate in the same direction, and the second transmission output gear 34B meshing with the second transmission secondary driven gear 33B rotates in the C' direction, which is opposite to the B1 direction and the same direction as the C direction. When the second transmission output gear 34B rotates in the C' direction, the first conversion drive gear 41A, which is integral with the second transmission output gear 34B via the first output shaft 40A, rotates in the same direction. Then, the first conversion driven gear 42A meshing with the first conversion drive gear 41A rotates in the D direction, causing the axle 37, which is integral with the first conversion driven gear 42A, to rotate in the same direction.

[0100] At this time, when the rotation speed of the second input shaft 25B is reduced relative to the rotation speed of the first input shaft 25A, the rotation speed input to the second transmission main driven gear 32B and the second transmission secondary driven gear 33B of the drive wheels 150 becomes lower than the rotation speed input to the first transmission main driven gear 32A and the first transmission secondary driven gear 33A. Then, the turning shaft 35 rotates by the rotation speed difference, and the wheels 15 turn and are steered. Also, when the rotation of the first input shaft 25A or the second input shaft 25B is stopped, the rotation speed input to the first transmission main driven gear 32A and the first transmission secondary driven gear 33A or the rotation speed input to the second transmission main driven gear 32B and the second transmission secondary driven gear 33B becomes zero, and the wheels 15 turn and are steered without rotating.

[0101] As shown in FIG. 21, the drive wheel 150 and the bogie 100 can operate in the same manner as the drive wheel 110 and the bogie 100 of the first embodiment, and can obtain the same effects as the drive wheel 110 and the bogie 100.

[0102] In particular, in the drive wheel 150, the output shaft is a single first output shaft 40A, and a first transmission output gear 34A and a second transmission output gear 34B are fixed coaxially to the first output shaft 40A, the first transmission gear mechanism 13A has a rotation-reverse gear 33Aa with which the first transmission secondary driven gear 33A meshes, and the rotation-reverse gear 33Aa meshes with the first transmission output gear 34A, and the second transmission gear mechanism 13B has a second transmission secondary driven gear 33B meshed with the second transmission output gear 34B.

[0103] According to this drive wheel 150, the rotational force of the first input shaft 25A and the second input shaft 25B is transmitted to the first output shaft 40A. Furthermore, in this drive wheel 150, the first conversion gear mechanism 14A transmits the rotational force of the first output shaft 40A to the axle 37. As a result, the basic configuration of the drive wheel 150 can be simplified.

[0104] Moreover, the bogie 100 of the embodiment includes the above-described drive wheels 150 and the bogie body 101 to which the drive wheels 150 are attached. Therefore, the basic structure of the bogie 100 can be simplified.

[0105] [Sixth embodiment of drive wheel] Fig. 22 is a perspective view showing the basic configuration of a drive wheel of the sixth embodiment. Fig. 23 is a cross-sectional view showing the drive system of the drive wheel of the sixth embodiment. Fig. 24 is a perspective view showing the drive system of the drive wheel of the sixth embodiment. Fig. 25 is a schematic diagram showing the drive force transmission path of the drive wheel of the sixth embodiment.

[0106] The drive wheel 160 of the sixth embodiment differs from the drive wheel 110 described above in the configurations of the transmission mechanism 13 and the power conversion mechanism 14. In the following description of the drive wheel 160 of the sixth embodiment, parts equivalent to those of the drive wheel 110 described above are denoted by the same reference numerals, and description thereof will be omitted.

[0107] The transmission mechanism 13 has a first transmission mechanism 13A and a second transmission gear mechanism (second transmission mechanism) 13B.

[0108] The first transmission mechanism 13A transmits the rotational force of the first drive shaft 22Ac to the first output shaft 40A via the first input shaft 25A. In the first transmission mechanism 13A, the first input shaft 25A and the first output shaft 40A are integrally formed and disposed to extend in the vertical direction Z. That is, the first input shaft 25A and the first output shaft 40A can be configured as the same thing. The first input shaft 25A and the first output shaft 40A are rotatably supported on the main body 10 via bearings 43b (see FIG. 23). Furthermore, the first input shaft 25A and the first output shaft 40A are rotatably supported on the pivot shaft 35 via bearings 43a (see FIG. 23). Therefore, the first input shaft 25A and the first output shaft 40A are supported rotatably relative to the revolving shaft 35 about the coaxial axis O1 (the axis of the first input shaft 25A) and the axis O3 (the axis of the first output shaft 40A), and are also supported rotatably relative to the main body 10 about the axes O1 and O3. In other words, the revolving shaft 35 is rotatable relative to the main body 10 regardless of the rotation of the first input shaft 25A. Therefore, the drive wheel 160 of the embodiment can input a rotational force to the first input shaft 25A on the axis O1, which is the revolving axis of the wheel 15.

[0109] In the first transmission mechanism 13A, the first input shaft 25A is fixed integrally to the first drive shaft 22Ac of the first drive mechanism 22A, and rotates about the axis O6 of the first drive shaft 22Ac by the rotational force generated by the first drive mechanism 22A. That is, the axis O1 of the first input shaft 25A, the axis O3 of the first output shaft 40A, and the axis O6 of the first drive shaft 22Ac are integrally arranged on the same axis and rotate integrally.

[0110] The second transmission gear mechanism 13B transmits the rotational force of the second drive shaft 22Bc to the second output shaft 40B via the second input shaft 25B. The second transmission gear mechanism 13B includes a second transmission drive gear 31B, a second transmission main driven gear 32B, a second transmission secondary driven gear 33B, a counter-rotating gear 33Ba, and a second transmission output gear 34B. In the drive wheel 160 of this embodiment, the second transmission drive gear 31B, the second transmission main driven gear 32B, the second transmission secondary driven gear 33B, the counter-rotating gear 33Ba, and the second transmission output gear 34B are each composed of a spur gear.

[0111] In the second transmission gear mechanism 13B, the second transmission drive gear 31B is fixed to the second drive shaft 22Bc of the second drive mechanism 22B and rotates about the axis O7 of the second drive shaft 22Bc by the rotational force of the second drive mechanism 22B. The second transmission main driven gear 32B and the second transmission secondary driven gear 33B are fixed to the second input shaft 25B and rotate about the axis O1 of the second input shaft 25B. The rotation counter gear 33Ba is supported on the pivot shaft 35 via a bearing 53 (see FIG. 23 ) so as to be rotatable about the axis O9 parallel to the axes O1 and O4. The second transmission output gear 34B is fixed to the second output shaft 40B and rotates about the axis O4 of the second output shaft 40B. The second transmission drive gear 31B meshes with the second transmission main driven gear 32B. The second transmission secondary driven gear 33B meshes with a rotation-reversing gear 33Ba. The rotation-reversing gear 33Ba meshes with a second transmission output gear 34B. Therefore, the second transmission gear mechanism 13B transmits the rotational force of the second drive mechanism 22B from the second transmission drive gear 31B to the second transmission main driven gear 32B to impart the rotational force to the second input shaft 25B, and further reverses the rotational force of the second input shaft 25B from the second transmission secondary driven gear 33B by the rotation-reversing gear 33Ba and transmits it to the second transmission output gear 34B to impart the rotational force to the second output shaft 40B.

[0112] The power conversion mechanism 14 has a first conversion gear mechanism (first power conversion mechanism) 14A and a second conversion gear mechanism (second power conversion mechanism) 14B.

[0113] The first conversion gear mechanism 14A transmits the rotational force of the first output shaft 40A to the axle 37. The first conversion gear mechanism 14A is composed of a first conversion drive gear 41A and a conversion driven gear 42. In the drive wheel 160, the first conversion drive gear 41A and the conversion driven gear 42 are composed of cross-hair gears.

[0114] The first conversion drive gear 41A is fixed to the lower part of the first output shaft 40A and rotates around the axis O3 together with the first output shaft 40A. The conversion driven gear 42 is fixed to the axle 37 and rotates around the axis O2 of the axle 37. The first conversion drive gear 41A meshes with the conversion driven gear 42. Therefore, the first conversion gear mechanism 14A converts the rotation of the first output shaft 40A around the axis O3 into rotation around the axis O2 of the axle 37.

[0115] The second conversion gear mechanism 14B transmits the rotational force of the second output shaft 40B to the axle 37. The second conversion gear mechanism 14B is composed of a second conversion drive gear 41B and the conversion driven gear 42. In the drive wheel 160, the second conversion drive gear 41B is composed of a cross gear.

[0116] The second conversion drive gear 41B is fixed to the lower part of the second output shaft 40B and rotates around the axis O4 together with the second output shaft 40B. The second conversion drive gear 41B meshes with the conversion driven gear 42. Therefore, the second conversion gear mechanism 14B converts the rotation of the second output shaft 40B around the axis O4 into rotation of the axle 37 around the axis O2.

[0117] In this power conversion mechanism 14, the first conversion drive gear 41A of the first conversion gear mechanism 14A and the second conversion drive gear 41B of the second conversion gear mechanism 14B have the same pitch circle diameter and the same number of teeth.

[0118] In the drive wheel 160, the first output shaft 40A and the second output shaft 40B are both disposed on one end side of the axle 37. The first output shaft 40A has an axis O1, which is the center of the pivot shaft 35, and an axis O3 that is coaxial with each other. The second output shaft 40B has an axis O4 that is offset in the front-to-rear direction X from the axis O3 of the first output shaft 40A. In the power conversion mechanism 14, a first conversion drive gear 41A is fixed to the first output shaft 40A, and a second conversion drive gear 41B is fixed to the second output shaft 40B, and these gears mesh with a conversion driven gear 42 fixed to the axle 37. With this configuration, the drive wheel 160 is disposed such that the rotation axis O5 of the wheel 15, which is aligned along the vertical direction intersecting the axis O2 of the axle 37, is offset in the horizontal direction (approximately the front-to-rear direction X) perpendicular to the axis O2 of the axle 37, from the axis O1 of the pivot shaft 35.

[0119] Here, the operation of the drive wheel 160 will be described. As shown in FIG. 25 , when the first input shaft 25A of the drive wheel 160 rotates in the A1 direction, the first output shaft 40A integral with the first input shaft 25A rotates in the same direction, A2, and the first conversion drive gear 41A rotates in the same direction via the first output shaft 40A. Then, the conversion driven gear 42 meshing with the first conversion drive gear 41A rotates in the D direction, imparting a rotational force in the D direction to the axle 37 integral with the conversion driven gear 42. Meanwhile, when the second input shaft 25B of the drive wheel 160 rotates in the B1 direction, which is opposite to the A1 direction, the second transmission main driven gear 32B and the second transmission secondary driven gear 33B rotate in the same direction. Then, the second transmission output gear 34B rotates in the B2 direction, which is opposite to the A2 direction of the first output shaft 40A, via the rotation-reversing gear 33Ba meshing with the second transmission secondary driven gear 33B. When the second transmission output gear 34B rotates in the B2 direction, the second conversion drive gear 41B, which is integrally provided with the second transmission output gear 34B via the second output shaft 40B, rotates in the same direction. As a result, the conversion driven gear 42 meshing with the second conversion drive gear 41B rotates in the D direction, imparting a rotational force in the D direction to the axle 37 integral with the conversion driven gear 42. Here, since the A2 direction and the B2 direction are opposite rotational directions, if the first input shaft 25A and the second input shaft 25B rotate at the same rotation speed, the wheel 15 rotates without turning.

[0120] At this time, when the rotation speed of the second input shaft 25B is reduced relative to the rotation speed of the first input shaft 25A, the rotation speed input from the second conversion drive gear 41B to the axle 37 via the conversion driven gear 42 becomes lower than the rotation speed input from the first conversion drive gear 41A to the axle 37 via the conversion driven gear 42. This causes the turning shaft 35 to rotate by the rotation speed difference, turning and steering the wheels 15. Furthermore, when the rotation of the first input shaft 25A or the second input shaft 25B is stopped, the rotation speed input from the first conversion drive gear 41A or the second conversion drive gear 41B to the axle 37 via the conversion driven gear 42 becomes zero, and the wheels 15 turn and steer without rotating.

[0121] As shown in FIG. 21, the drive wheel 160 and the bogie 100 can operate in the same manner as the drive wheel 110 and the bogie 100 of the first embodiment, and can obtain the same effects as the drive wheel 110 and the bogie 100.

[0122] In particular, in the drive wheel 160, the rotational force of the first input shaft 25A is directly transmitted to the first output shaft 40A. Furthermore, in this drive wheel 160, the first conversion gear mechanism 14A transmits the rotational force of the first output shaft 40A to the conversion driven gear 42, which is a predetermined part of the axle 37, and the second conversion gear mechanism 14B transmits the rotational force of the second output shaft 40B to the conversion driven gear 42, which is the predetermined part of the axle 37. As a result, the basic configuration of the drive wheel 160 can be simplified.

[0123] Moreover, the bogie 100 of the embodiment includes the above-described drive wheels 160 and the bogie body 101 to which the drive wheels 160 are attached. Therefore, the basic structure of the bogie 100 can be simplified.

[0124] [Modifications] In the above-described drive wheels 110, 120, 130, 140, 150, and 160, the transmission mechanism 13 has been described as a spur gear, but this is not limited thereto. For example, the transmission mechanism 13 may be a helical gear. Furthermore, in the above-described drive wheels 110, 120, 130, and 140, the power conversion mechanism 14 has been described as a bevel gear, but this is not limited thereto. For example, although not explicitly shown in the figures, the power conversion mechanism 14 may be a screw gear, a helical gear, a worm gear, a crown gear, a universal joint, or the like. Furthermore, in the above-described drive wheel 150, the power conversion mechanism 14 has been described as a screw gear, but this is not limited thereto. For example, although not explicitly shown in the figures, the power conversion mechanism 14 may be a bevel gear, a helical gear, a worm gear, a crown gear, a universal joint, or the like. Furthermore, in the above-described drive wheel 160, the power conversion mechanism 14 has been described as a screw gear, but this is not limited thereto. For example, although not shown, the power conversion mechanism 14 may be a bevel gear, a helical gear, a worm gear, a crown gear, or the like.

[0125] 13A First transmission gear mechanism (first transmission mechanism) 13B Second transmission gear mechanism (second transmission mechanism) 14A First conversion gear mechanism (first power conversion mechanism) 14B Second conversion gear mechanism (second power conversion mechanism) 15 Wheel 22A First drive mechanism 22Ac First drive shaft 22B Second drive mechanism 22Bc Second drive shaft 23A First belt mechanism 23B Second belt mechanism 25A First input shaft 25B Second input shaft 25C Angle detection shaft 31A First transmission drive gear 31B Second transmission drive gear 32A First transmission main driven gear 32B Second transmission main driven gear 33Aa Rotation counter gear 33A First transmission secondary driven gear 33B Second transmission secondary driven gear 34A First transmission output gear 34B Second transmission output gear 35 Swivel shaft 37 Axle 40A First output shaft (output shaft) 40B Second output shaft (output shaft) 50 Angle detector 100 Bogie 101 Bogie body 110, 120, 130, 140, 150, 160 Drive wheels

Claims

1. A drive wheel comprising: a first drive mechanism having a first drive shaft; a second drive mechanism having a second drive shaft; first and second input shafts on the same axis; an output shaft; a first transmission mechanism for transmitting a rotational force of the first drive shaft to the output shaft via the first input shaft; a second transmission mechanism for transmitting a rotational force of the second drive shaft to the output shaft via the second input shaft; a rotatable axle to which a wheel is fixed; a power conversion mechanism for transmitting the rotational force of the output shaft to the axle; and a turning shaft for rotatably supporting the wheel via the axle, wherein the second transmission mechanism includes a gear fixed to the second input shaft and loosely fitted around the first input shaft.

2. The drive wheel according to claim 1, wherein the first transmission mechanism includes a first transmission drive gear fixed to the first drive shaft, a first transmission main driven gear fixed to the first input shaft and meshing with the first transmission drive gear, and a first transmission secondary driven gear fixed to the first input shaft for transmitting rotational force to the output shaft, and the second transmission mechanism includes a second transmission drive gear fixed to the second drive shaft, a second transmission main driven gear fixed to the second input shaft and meshing with the second transmission drive gear, and a second transmission secondary driven gear fixed to the second input shaft integrally with the second transmission main driven gear for transmitting rotational force to the output shaft.

3. A driving wheel as described in claim 1, wherein the output shaft includes a first output shaft and a second output shaft on separate axes, the first transmission mechanism transmits the rotational force of the first input shaft to the first output shaft, the second transmission mechanism transmits the rotational force of the second input shaft to the second output shaft, and the power conversion mechanism includes a first power conversion mechanism that transmits the rotational force of the first output shaft to one end of the axle, and a second power conversion mechanism that transmits the rotational force of the second output shaft to the other end of the axle.

4. A drive wheel as described in claim 1, wherein the first drive mechanism includes a first drive section having the first drive shaft as an output shaft, and the second drive mechanism includes a second drive section having the second drive shaft as an output shaft.

5. A drive wheel as described in claim 1, wherein the first drive mechanism applies a rotational force to the first drive shaft via a first belt mechanism, and the second drive mechanism applies a rotational force to the second drive shaft via a second belt mechanism.

6. The drive wheel according to claim 1, further comprising an angle detection shaft that is arranged coaxially with the first input shaft and the second input shaft, fixed to the rotating shaft, and connected to an angle detector.

7. A drive wheel according to claim 2, wherein, in the first transmission mechanism, the first transmission main driven gear has a smaller pitch circle diameter than the first transmission secondary driven gear, and, in the second transmission mechanism, the second transmission main driven gear has a smaller pitch circle diameter than the second transmission secondary driven gear.

8. A driving wheel as set forth in claim 2, wherein the output shaft is a single one, and a first transmission output gear and a second transmission output gear are fixed coaxially to the output shaft, the first transmission mechanism has a rotation-reversing gear with which the first transmission secondary driven gear meshes, and the rotation-reversing gear meshes with the first transmission output gear, and the second transmission mechanism has a second transmission secondary driven gear with which the second transmission output gear meshes.

9. A drive wheel as described in claim 1, wherein the output shaft includes a first output shaft and a second output shaft on separate axes, the first transmission mechanism integrally connects the first input shaft and the first output shaft, and the power conversion mechanism includes a first power conversion mechanism that transmits the rotational force of the first output shaft to a specified portion of the axle, and a second power conversion mechanism that transmits the rotational force of the second output shaft to the specified portion of the axle.

10. The drive wheel according to claim 9, wherein the first drive mechanism has the first drive shaft integrally connected to the first input shaft, and the second drive mechanism has a gear of the second transmission mechanism fixed to the second drive shaft.

11. A drive wheel according to any one of claims 1 to 10, wherein the axis of rotation of the wheel, which runs vertically and intersects with the axis of the axle, is shifted horizontally relative to the axis of the pivot shaft in a direction perpendicular to the axis of the axle.

12. A bogie comprising: a drive wheel; and a bogie body to which the drive wheel is attached, wherein the drive wheel comprises: a first drive mechanism having a first drive shaft; a second drive mechanism having a second drive shaft; coaxial first and second input shafts; an output shaft; a first transmission mechanism for transmitting the rotational force of the first drive shaft to the output shaft via the first input shaft; a second transmission mechanism for transmitting the rotational force of the second drive shaft to the output shaft via the second input shaft; a rotatable axle to which a wheel is fixed; a power conversion mechanism for transmitting the rotational force of the output shaft to the axle; and a swivel shaft for rotatably supporting the wheel via the axle, wherein the second transmission mechanism includes a gear fixed to the second input shaft and loosely fitted around the first input shaft.

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