Drive wheel and electrically assisted vehicle

Abstract

To provide a drive wheel and an electrically assisted vehicle which are compact and excellent in durability.SOLUTION: The drive wheel includes: a drive bracket 31; a speed-reducer-equipped motor 32 fixed to the drive bracket 31 and configured to produce torque; a bearing 43 provided for the drive bracket 31; a drive axle 33 having a first end 33a supported on the drive bracket 31 with the bearing 43 interposed therebetween so as to be rotatable; and a drive wheel body 34 provided for the drive axle 33 and configured to rotate integrally with the drive axle 33. The speed-reducer-equipped motor 32 includes a case 51 fixed to the drive bracket 31 and a rotation output part 82 supported on the case 51 with a fourth bearing 81 interposed therebetween so as to be rotatable. The drive axle 33 has a second end 33b integrated with the rotation output part 82, and the second end 33b is supported on the case 51 with the rotation output part 82 and the fourth bearing 81 interposed therebetween so as to be rotatable.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to drive wheels and electric assist vehicles.

Background Art

[0002] Conventionally, an electric assist vehicle having drive wheels (drive wheels) provided at the lower part of a carriage has been known (see, for example, Patent Document 1). When moving the carriage manually, this vehicle can reduce the moving burden of the carriage because the drive wheels assist. For example, the drive wheel described in Patent Document 1 includes a torque transmission mechanism portion fixed to a bracket extending downward from the carriage, and an electric motor and a wheel attached to the torque transmission mechanism portion. The torque transmission mechanism portion includes a housing fixed to the bracket and a drive shaft protruding from the housing. The torque transmission mechanism portion outputs the rotation of the electric motor from the drive shaft. A wheel is attached to this drive shaft. That is, the drive shaft also serves as the axle of the wheel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when trying to use an electric assist vehicle for various purposes, for example, it is assumed that the electric assist vehicle is used on rough outdoor roads. However, in the above-mentioned conventional technology, since the drive shaft serving as the axle is cantilever-supported by the housing, the durability is low. For this reason, there was a possibility that problems would occur in the electric assist vehicle when used on rough roads. When trying to improve the durability by increasing the rigidity of the torque transmission mechanism portion, there is a problem that the device becomes large-sized and the usability of the electric assist vehicle deteriorates, such as becoming heavy.

[0005] Therefore, the present invention provides a drive wheel and an electric assist vehicle that are small in size and excellent in durability.

Means for Solving the Problems

[0006] In order to solve the above problems, in a first aspect of the present invention, the drive wheel includes a bracket, a drive unit fixed to the bracket that generates a rotational force, a first bearing provided on the bracket, an axle having a first end rotatably supported by the bracket via the first bearing, and a wheel body provided on the axle and rotating integrally with the axle. The drive unit includes a case fixed to the bracket and a rotational output unit rotatably supported by the case via a second bearing. The second end of the axle, which is opposite to the first end, is integrated with the rotational output unit, and the second end is rotatably supported by the case via the rotational output unit and the second bearing.

[0007] By configuring in this way, while utilizing the second bearing provided in the drive unit, the axle can be supported in a two-bearing manner in cooperation with the first bearing provided in the bracket. Therefore, a drive wheel that is small in size and excellent in durability can be provided.

[0008] In a second aspect of the present invention, in the drive wheel of the first aspect, the drive unit is a motor with a speed reducer. The motor with a speed reducer includes an electric motor housed in the case and a speed reduction mechanism unit housed in the case that reduces the rotation of the electric motor. The speed reduction mechanism unit includes the rotational output unit.

[0009] In this way, by utilizing the speed reduction mechanism unit, it becomes possible to obtain a high output even when the electric motor is miniaturized. Also, since the bearing in the speed reduction mechanism unit can be the second bearing, the entire drive unit can be miniaturized.

[0010] In the third aspect of the present invention, the electric vehicle includes the drive wheels of the first aspect or the second aspect, and a vehicle body provided with the drive wheels. The drive wheels are provided at least one on each of both sides in the vehicle width direction below the vehicle body, and the drive unit is disposed inside the vehicle width direction of the wheel body.

[0011] By configuring in this way, it is not necessary to provide, for example, an axle for transmitting power between the drive wheels disposed on both sides in the vehicle width direction. Therefore, a sufficient space for passing foreign objects can be secured under the vehicle body. In addition, since the drive wheels have excellent durability, an electric vehicle that is easy to use even on rough roads can be provided. Further, since the drive unit is disposed inside the vehicle width direction of the wheel body, a small-sized electric vehicle with the vehicle width direction dimension suppressed as much as possible can be provided.

[0012] In the fourth aspect of the present invention, in the electric vehicle of the third aspect, the vehicle body is foldable between the two drive wheels disposed at least on both sides in the vehicle width direction.

[0013] No axle or the like is provided between the drive wheels disposed on both sides in the vehicle width direction. Therefore, the vehicle body can be folded between the two drive wheels disposed on both sides in the vehicle width direction. Thus, the arrangement space of the electric vehicle when not in use can be made as space-saving as possible.

[0014] In the fifth aspect of the present invention, in the electric vehicle of the third aspect or the fourth aspect, the drive wheels are detachably provided on the vehicle body. The drive wheels include a drive-side connector detachably provided on a power-source-side connector attached to a power-source-side harness extending from the power source of the vehicle body, and a drive-side harness electrically connecting the drive-side connector and the drive unit. The drive-side connector is fixed to the bracket.

[0015] By configuring it in this way, even when a power source is provided on the vehicle body side, the drive wheels can be easily attached to or detached from the vehicle body. By detaching the drive wheels, it becomes possible to stably place the vehicle body on the floor surface. In this way, a user-friendly electric vehicle can be provided.

Advantages of the Invention

[0016] According to the present invention, the drive wheels and the electric assist vehicle can be miniaturized and the durability can be improved.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0018] Next, embodiments of the present invention will be described with reference to the drawings.

[0019] <Electric Assist Basket Cart> FIG. 1 is a perspective view of an electric assist basket cart 1 as an electric assist vehicle. In the following description, the vertical direction and the horizontal direction shall refer to the state in which the electric assist basket cart 1 is placed on the road surface R. As shown in FIG. 1, the electric assist basket cart 1 includes a loading platform 2, a handle 3 provided on the loading platform 2, an operation unit 4 provided on the handle 3, and drive wheels 5 and driven wheels 6 provided below the loading platform 2.

[0020] The loading platform 2 includes a rectangular parallelepiped-shaped frame body 7 that is rectangular in shape and long in one direction when viewed from the vertical direction, and a basket body 8 housed in the frame body 7. The basket body 8 is formed of a deformable material such as a net, for example. Further, the basket body 8 is formed in a rectangular parallelepiped shape so as to correspond to the frame body 7, and has an opening 8a at the upper part. Of the side surfaces of the frame body 7, the short side surfaces 8b on both sides in the longitudinal direction of the basket body 8 can be folded so as to approach and separate from each other. Further, of the side surfaces of the frame body 7, the long side surfaces 8c on both sides in the short side direction of the basket body 8 can be folded so as to approach and separate from each other.

[0021] The handle 3 includes a support column 11 extending upward from the frame body 7 on one of the two short side surfaces 8b, and an annular grip portion 12 provided at the upper end of the support column 11. The user moves forward by pulling the electric assist basket cart 1 while holding the grip portion 12. That is, for the electric assist basket cart 1, the side on which the handle 3 of the short side surface 8b is provided is the front in the traveling direction. The traveling direction coincides with the longitudinal direction of the basket body 8.

[0022] In the following description, the longitudinal direction of the loading platform 2 is referred to as the front-rear direction, and the short side direction of the loading platform 2 orthogonal to the front-rear direction is referred to as the vehicle width direction. In the vehicle width direction, the right side and the left side when looking forward may be simply referred to as the right side and the left side. In FIG. 1, the postures of the drive wheels 5 and the driven wheels 6 are the postures when the electric assist basket cart 1 travels straight forward or backward. When explaining the drive wheels 5 and the driven wheels 6, the explanation is based on the posture when the electric assist basket cart 1 travels straight forward or backward.

[0023] The operation unit 4 controls the drive of the drive wheels 5. The operation unit 4 includes an operation unit main body 13 and a control device (not shown) that controls the drive of the drive wheels 5 based on the operation of the operation unit main body 13. The operation unit main body 13 is, for example, a so-called joystick. The operation unit main body 13 includes a housing 14 fixed to the grip part 12 and a lever 15 tiltably supported by the housing 14. Information on the tilting direction of the lever 15 is output as a signal to the control device. The control device performs drive control of the drive wheels 5 based on the signal output from the lever 15.

[0024] Two drive wheels 5 and two driven wheels 6 are respectively provided. The drive wheels 5 and the driven wheels 6 are provided at the four corners of the lower part of the frame body 7. More specifically, the drive wheels 5 are provided at the rear and on both sides in the vehicle width direction of the lower part of the frame body 7. The driven wheels 6 are provided at the front and on both sides in the vehicle width direction of the lower part of the frame body 7. In this way, the distance between the drive wheels 5 and the driven wheels 6 arranged in the front-rear direction is longer than the distance between the two drive wheels 5 arranged in the vehicle width direction and the distance between the two driven wheels 6.

[0025] The driven wheel 6 includes a driven bracket 21 rotatably and detachably provided on the frame body 7, a driven axle 22 rotatably supported by the driven bracket 21, and a driven wheel body 23 fixed to the driven axle 22. Since the configuration of the driven bracket 21 is the same as that of the drive bracket 31 described later, the description here is omitted. The driven wheel body 23 includes a wheel 24 fitted and fixed to the driven axle 22 and a tire 25 fitted to the outer peripheral surface of the wheel 24.

[0026] <Drive Wheel> The two drive wheels 5 have the same configuration and are arranged symmetrically about the center in the vehicle width direction. Therefore, in the following description, only the drive wheel 5 arranged on the right side among the two drive wheels 5 will be described, and the description of the drive wheel 5 arranged on the left side will be omitted.

[0027] FIG. 2 is a perspective view of the drive wheel 5 on the right side as viewed obliquely from the front. FIG. 3 is a cross-sectional view taken along the rotation axis A1 of the drive wheel 5 shown in FIG. 2. As shown in FIGS. 1 to 3, the drive wheel 5 includes a drive bracket 31 rotatably and detachably provided on the frame body 7, a motor with a speed reducer 32 fixed to the drive bracket 31, a drive axle 33 supported by the motor with a speed reducer 32 and the drive bracket 31, and a drive wheel body 34 attached to the drive axle 33.

[0028] <Drive Bracket> The drive bracket 31 includes a support column 35 that can be inserted into and removed from the frame body 7 in the vertical direction, and a bracket body 36 integrally formed at the lower end of the support column 35. The support column 35 is formed long in the vertical direction. The support column 35 is rotatable around the axis A2 with respect to the frame body 7. The bracket body 36 is formed by bending a strip-shaped metal plate through pressing, and is formed in a U shape with an opening at the bottom. That is, the bracket body 36 includes a top plate 37 and two side plates 38, 39 (the first side plate 38 and the second side plate 39) that bend and extend downward from both sides in the vehicle width direction of the top plate 37.

[0029] Among the two side plates 38, 39, a through hole 38a penetrating the first side plate 38 in the thickness direction is formed at the lower end of the first side plate 38 on the outer side in the vehicle width direction (the left side in FIGS. 2 and 3). The first end portion 33a of the drive axle 33 on the outer side in the vehicle width direction is inserted into the through hole 38a. A bearing unit 41 is provided on the outer surface 38b on the outer side in the vehicle width direction (the left side) at the lower end of the first side plate 38. The bearing unit 41 includes a bearing housing 42 fixed to the outer surface 38b of the first side plate 38, and a bearing (an example of the first bearing in the claims) 43 housed in the bearing housing 42. The first end portion 33a of the drive axle 33 inserted into the through hole 38a is rotatably supported by this bearing 43.

[0030] <Motor with a Speed Reducer> The motor 32 with a speed reducer is fixed to the second side plate 39 on the inner side in the vehicle width direction (the right side in FIGS. 2 and 3) of the two side plates 38 and 39 by bolts 49 via a mounting stay 50. The motor 32 with a speed reducer includes a case 51 fixed to the inner surface 39a on the outer side in the vehicle width direction of the second side plate 39, and an electric motor 52 and a speed reduction mechanism portion 53 housed coaxially with the rotation axis A1 in the case 51. Hereinafter, the direction parallel to the rotation axis A1 will be referred to as the axial direction, the rotation direction centered on the rotation axis A1 will be referred to as the circumferential direction, and the direction orthogonal to the axial direction and the circumferential direction will be referred to as the radial direction for explanation.

[0031] The case 51 is formed such that its outer diameter gradually decreases toward the outer side in the vehicle width direction (the first side plate 38 side). An opening 51a is formed on the inner side in the vehicle width direction (the second side plate 39 side) of the case 51. A cover 54 is attached to the case 51 so as to close the opening 51a.

[0032] As the electric motor 52, for example, an inner rotor type brushless motor is used. The electric motor 52 includes a stator 55 fixed to the opening 51a side of the case 51, a rotor 56 disposed on the inner side in the radial direction of the stator 55, and a control board 59 disposed on the inner side in the vehicle width direction of the stator 55 and the rotor 56. The electric motor 52 is covered by the cover 54 from above the control board 59.

[0033] The stator 55 includes a stator core 57 formed in an annular shape and a coil 58 wound around the stator core 57. The stator core 57 is fixed to the case 51 such that the outer peripheral surface of the stator core 57 is fitted to the inner peripheral surface of the case 51. The coil 58 is connected to the control board 59.

[0034] The rotor 56 includes a rotor shaft 64 rotatably supported on the case 51 and the speed reduction mechanism portion 53 via a first bearing 61, a second bearing 62, and a third bearing 63, a disk-shaped rotor core 65 fitted and fixed to the rotor shaft 64, and a permanent magnet 66 provided on the outer peripheral surface of the rotor core 65. The axis A3 of the rotor shaft 64 coincides with the rotation axis A1. The permanent magnet 66 faces the stator 55 in the radial direction.

[0035] A plurality of switching elements (not shown in the figure) and a sensor 67 for detecting the rotation angle of the rotor shaft 64 are mounted on the control board 59. The sensor 67 outputs the information on the detected rotation angle of the rotor shaft 64 as a signal. Further, a motor harness 71 and a sensor harness 72 are connected to the control board 59.

[0036] The motor harness 71 is electrically connected to the coil 58. The sensor harness 72 is electrically connected to the sensor 67. These harnesses 71, 72 are drawn out to the outside through the case 51. A drive-side motor connector 73 is connected to the end of the drawn-out motor harness 71. A drive-side sensor connector 74 is connected to the end of the drawn-out sensor harness 72. These connectors 73, 74 are fixed to the drive bracket 31.

[0037] The speed reduction mechanism portion 53 is housed outside the electric motor 52 in the vehicle width direction of the case 51. For example, a so-called hypocycloid speed reduction mechanism is used for the speed reduction mechanism portion 53. The speed reduction mechanism portion 53 includes a rotation output portion 82 rotatably supported on the case 51 via a fourth bearing (an example of the second bearing in the claims) 81, and a plurality of gears 83 that reduce the rotation of the rotor shaft 64 and transmit it to the rotation output portion 82. Thereby, the rotation of the rotor shaft 64 is reduced and output by the rotation output portion 82.

[0038] The second end portion 33b of the drive axle 33 opposite to the first end portion 33a is fixed to the rotary output portion 82. More specifically, an outer flange portion 33c that projects radially outward is integrally formed on the second end portion 33b of the drive axle 33. A plurality of bolt insertion holes 84 penetrating in the axial direction are formed in the outer flange portion 33c. The bolt insertion holes 84 are arranged at equal intervals in the circumferential direction. A plurality of female screw portions 82a communicating with the bolt insertion holes 84 are formed in the rotary output portion 82.

[0039] Bolts 85 are respectively inserted into the bolt insertion holes 84 from above the outer flange portion 33c, and these bolts 85 are tightened to the female screw portions 82a. Thereby, the second end portion 33b of the drive axle 33 is fixed to the rotary output portion 82, and the drive axle 33 and the rotary output portion 82 are integrated. That is, the first end portion 33a of the drive axle 33 is rotatably supported by the drive bracket 31 via the bearing 43. The second end portion 33b of the drive axle 33 is rotatably supported by the case 51 via the rotary output portion 82 and the fourth bearing 81.

[0040] <Drive wheel body> The drive wheel body 34 is provided between the speed reduction motor 32 and the first side plate 38 of the drive bracket 31 in the drive axle 33. The drive wheel body 34 includes a wheel 101 fitted and fixed to the drive axle 33, and a tire 102 fitted to the outer peripheral surface of the wheel 101.

[0041] In addition, the electric assist wheelchair cart 1 is provided with a battery (power source) (not shown). A power supply side harness 91 is connected to the battery. The power supply side harness 91 extends between the battery and the drive bracket 31. A power supply side connector 92 is connected to the end of the power supply side harness 91. A drive side motor connector 73 is connected to the power supply side connector 92. Thereby, the power of the battery is supplied to the coil 58 via the control board 59.

[0042] In addition, a control harness 93 (not shown) is connected to a control device (not shown). The control harness 93 extends from the control device (not shown) to the drive bracket 31. A control connector 94 is connected to the end of the control harness 93. A drive-side sensor connector 74 is connected to the control connector 94. As a result, the information on the rotation angle of the rotor shaft 64 detected by the sensor 67 on the control board 59 is output to the control device as a signal.

[0043] <Operation of the Electric-Assist Basket Trolley> Next, the operation of the electric-assist basket trolley 1 will be described. When the user grips the grip portion 12 of the handle 3 and pulls the load platform 2 forward, the lever 15 of the operation unit 4 tilts forward. Then, a control device (not shown) drives the drive wheels 5 based on the operation of the lever 15. At this time, the power of a battery (not shown) is supplied to the respective coils 58 of the left and right drive wheels 5 via the control board 59. In each electric motor 52 of the drive wheels 5, power is selectively supplied to a desired coil 58 based on the rotation angle of the rotor shaft 64 by the sensor 67.

[0044] When power is supplied to the coil 58, a predetermined linked magnetic flux is formed in the stator 55. A magnetic attractive force or repulsive force is generated between this linked magnetic flux and the permanent magnet 66 of the rotor 56. As a result, the rotor 56 is rotated, and further, the rotation output unit 82 and the drive axle 33 are rotated via the speed reduction mechanism unit 53. Also, the drive wheel body 34 is rotated integrally with the drive axle 33. Thus, when the user attempts to move the load platform 2, it is assisted by the drive wheels 5.

[0045] Here, when you want to go straight ahead, keep the lever 15 tilted forward. In this case, the left and right drive wheels 5 continue to rotate at the same speed. On the other hand, for example, when you want to change the course of the electric assist wheelchair cart 1 diagonally forward, tilt the lever 15 in the direction of the desired course. Then, a control device (not shown) causes a speed difference to occur between the left and right drive wheels 5. For example, when you want to change the course of the electric assist wheelchair cart 1 to the right, slow down the rotational speed of the right drive wheel 5 with respect to the left drive wheel 5. As a result, the course of the electric assist wheelchair cart 1 is changed to the right.

[0046] The same applies when reversing the electric assist wheelchair cart 1. In this case, the user reverses by pushing the carrier 2. At this time, tilt the lever 15 backward. When you want to change the course of the electric assist wheelchair cart 1 diagonally backward, it is the same as the case of changing the course diagonally forward described above. In addition, for example, when the lever 15 is tilted in the left - right direction, the left and right drive wheels 5 are stopped.

[0047] When the electric assist wheelchair cart 1 is running, the drive axle 33 has its first end 33a rotatably supported by the drive bracket 31 via the bearing 43. The drive axle 33 has its second end 33b rotatably supported by the case 51 via the rotary output portion 82 and the fourth bearing 81. That is, the drive axle 33 is supported in a two - supported manner by the drive bracket 31 and the motor 32 with a speed reducer. Therefore, compared with the case of supporting the drive axle 33 in a cantilevered manner, the rigidity of the drive wheel 5 can be increased.

[0048] Therefore, according to the above - mentioned drive wheel 5, sufficient durability can be obtained even when the electric assist wheelchair cart 1 travels on a rough road. In order to support the drive axle 33 in a two - supported manner, the fourth bearing 81 of the motor 32 with a speed reducer is utilized. Therefore, in order to support the drive axle 33 in a two - supported manner, for example, it is not necessary to provide two bearings on the drive bracket 31. Thus, while improving the durability of the drive wheel 5, it can be miniaturized.

[0049] As a drive unit for the drive wheels 5, a motor 32 with a speed reduction mechanism 53 is used. By utilizing the speed reduction mechanism 53, it is possible to obtain high output even when the electric motor 52 is miniaturized. In addition, the drive axle 33 can be supported in a both-end-supported manner by utilizing the fourth bearing 81 in the speed reduction mechanism 53. Therefore, even when the motor 32 with a speed reduction mechanism is used, the drive wheels 5 as a whole can be miniaturized.

[0050] Separate motors 32 with speed reduction mechanisms are provided for the two drive wheels 5 respectively. Therefore, it is not necessary to provide, for example, an axle for power transmission between the left and right drive wheels 5. Thus, a sufficient space for passing foreign objects can be secured under the loading platform 2. In addition, since the drive wheels 5 have excellent durability, an electric assist basket cart 1 that is easy to use even on rough roads can be provided. The two drive wheels 5 have motors 32 with speed reduction mechanisms arranged inside them in the vehicle width direction respectively. Therefore, a small electric assist basket cart 1 with the vehicle width dimension suppressed as much as possible can be provided.

[0051] The frame 7 of the loading platform 2 is foldable such that the short side surfaces 8b on both sides in the longitudinal direction approach and separate from each other. Also, the frame 7 is foldable such that the long side surfaces 8c on both sides in the short direction approach and separate from each other. That is, since it is not necessary to provide, for example, an axle for power transmission between the left and right drive wheels 5, the frame 7 between these left and right drive wheels 5 can be folded. Therefore, when the electric assist basket cart 1 is not in use, the arrangement space of the electric assist basket cart 1 can be made as space-saving as possible.

[0052] The connectors 73 and 74 of each harness 71 and 72 drawn out from the motor 32 with a speed reducer are fixed to the drive bracket 31. Therefore, for example, when removing the drive wheel 5 from the loading platform 2, the power supply connector 92 is removed from the drive side motor connector 73. Also, the control side connector 94 is removed from the drive side sensor connector 74. By doing only this, the drive wheel 5 can be easily removed from the loading platform 2. In this way, while it is necessary to electrically connect a battery and control equipment (not shown) to the drive wheel 5, the drive wheel 5 and the loading platform 2 can be easily attached and detached. By removing the drive wheel 5, it is also possible to stably place the loading platform 2 on the road surface R. In this way, a user-friendly electric assist basket cart 1 can be provided.

[0053] Since the durability of the drive wheel 5 can be improved while reducing its size, it is possible to contribute to Goal 7, "Ensure access for all to affordable, reliable and sustainable modern energy", Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation", and Goal 12, "Ensure sustainable consumption and production patterns", of the Sustainable Development Goals (SDGs) led by the United Nations.

[0054] Since a user-friendly electric assist basket cart 1 can be provided, it is possible to contribute to Goal 11, "Make cities and human settlements inclusive, safe, resilient and sustainable", of the Sustainable Development Goals (SDGs) led by the United Nations.

[0055] The present invention is not limited to the above-described embodiments, and includes those obtained by making various changes to the above-described embodiments without departing from the gist of the present invention.

[0056] For example, in the above-described embodiment, the case where the drive wheel 5 and the operation unit 4 are provided on the electric assist basket cart 1 as an electric assist vehicle has been described. However, it is not limited to this, and the above-described drive wheel 5 and operation unit 4 can be applied to various loading platforms, carts, racks, wagons, etc. that require transportation. The shape of the loading platform 2 is not limited to a rectangular parallelepiped shape, and various shapes may be used.

[0057] In the above-described embodiment, the case where the electric assist cage bogie 1 is changed to a desired path by providing a speed difference between the left and right drive wheels 5 has been described. However, the present invention is not limited to this, and the path of the electric assist cage bogie 1 may be changed by rotating the left and right drive wheels 5 in opposite directions respectively.

[0058] In the above-described embodiment, the case where the frame body 7 is foldable such that the short side surfaces 8b on both sides in the longitudinal direction approach and separate from each other, and the frame body 7 is foldable such that the long side surfaces 8c on both sides in the short direction approach and separate from each other has been described. However, the present invention is not limited to this, and it is sufficient that the frame body 7 is foldable between at least two drive wheels 5 arranged on both sides in the vehicle width direction.

[0059] In the above-described embodiment, the case where a motor 32 with a speed reducer is provided as the drive unit of the drive wheel 5 has been described. However, the present invention is not limited to this, and any structure that serves as the drive source of the drive wheel body 34 may be used. For example, an electric motor 52 may be used alone instead of the motor 32 with a speed reducer. It is sufficient that the bearing provided in the drive unit and the bearing 43 provided in the drive bracket 31 cooperate to support the drive axle 33 in a two-bearing support manner.

[0060] In the above-described embodiment, the case where the drive bracket 31 has a bracket body 36 formed in a U shape with an opening at the bottom has been described. The case where a bearing unit 41 having a bearing 43 is provided on the outer surface 38b of the first side plate 38 of the bracket body 36 has been described. However, the present invention is not limited to this, and the shape of the drive bracket 31 and the arrangement position of the bearing 43 (bearing unit 41) can be arbitrarily changed.

Explanation of Reference Numerals

[0061] 1... Electric assist wheelchair (electric assist vehicle), 2... Loading platform (vehicle body), 3... Handle, 4... Operation unit, 5... Driving wheel, 6... Driven wheel, 7... Frame (vehicle body), 8... Wheelchair body (vehicle body), 8a... Opening, 8b... Short side surface, 8c... Long side surface, 11... Support column, 12... Gripping part, 13... Operation unit main body, 14... Housing, 15... Lever, 21... Driven bracket, 22... Driven axle, 23... Driven wheel body, 24... Wheel, 25... Tire, 31... Driving bracket (bracket), 32... Motor with speed reducer (driving part), 33... Driving axle (axle), 33a... First end, 33b... Second end, 33c... Outer flange part, 34... Driving wheel body (wheel body), 35... Support column, 36... Bracket main body, 37... Top plate, 38... First side plate, 38a... Through hole, 38b... Outer surface, 39... Second side plate, 39a... Inner surface, 41... Bearing unit, 42... Bearing housing, 43... Bearing (first bearing), 50... Mounting stay, 51... Case, 51a... Opening, 52... Electric motor, 53... Speed reduction mechanism part, 54... Cover, 55... Stator, 56... Rotor, 57... Stator core, 58... Coil, 59... Control board, 61... First bearing, 62... Second bearing, 63... Third bearing, 64... Rotor shaft, 65... Rotor core, 66... Permanent magnet, 67... Sensor, 71... Motor harness, 72... Sensor harness, 73... Driving side motor connector, 74... Driving side sensor connector, 81... Fourth bearing (second bearing), 82... Rotational output part, 82a... Female thread part, 83... Gear, 84... Bolt insertion hole, 85... Bolt, 91... Power supply side harness, 92... Power supply side connector, 93... Control side harness, 94... Control side connector, 101... Wheel, 102... Tire, A1... Axis of rotation, A2... Axle center, A3... Axle center, R... Road surface

Claims

1. A bracket, a drive unit fixed to the bracket and generating a rotational force, a first bearing provided on the bracket, an axle having a first end rotatably supported on the bracket via the first bearing, a wheel body provided on the axle and rotating integrally with the axle, characterized in that: the drive unit includes a case fixed to the bracket, a rotary output unit rotatably supported in the case via a second bearing, and is characterized in that a second end of the axle, opposite to the first end, is integrated with the rotary output unit, and the second end is rotatably supported in the case via the rotary output unit and the second bearing. A drive wheel characterized by the above.

2. The drive unit is a motor with a speed reducer, and the motor with a speed reducer includes an electric motor housed in the case, a speed reduction mechanism housed in the case and reducing the rotation of the electric motor, and is characterized in that the speed reduction mechanism includes the rotary output unit. The drive wheel according to claim 1, characterized by the above.

3. The drive wheel according to claim 1 or claim 2, and a vehicle body provided with the drive wheel, characterized in that: the drive wheels are provided one by one at least on both sides in the vehicle width direction below the vehicle body, and the drive unit is arranged inside the vehicle width direction of the wheel body. An electric assist vehicle characterized by the above.

4. The vehicle body is foldable between two drive wheels arranged at least on both sides in the vehicle width direction. The electric assist vehicle according to claim 3, characterized by the above.

5. The drive wheel is detachably provided on the vehicle body, and the drive wheel includes a drive-side connector detachably provided on a power-source-side connector attached to a power-source-side harness extending from the power source of the vehicle body, and a drive-side harness electrically connecting the drive-side connector and the drive unit, and is characterized in that the drive-side connector is fixed to the bracket. The electric assist vehicle according to claim 3, characterized by the above.

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