JP2014057672A - Wheel for wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel for power assistance that can be attached to or detached from a wheelchair, which is capable of imparting stable resistance force to a hand rim base part that swings to a wheel hub, with less maintenance load such as replacement of a component.SOLUTION: A hand rim base part 39 is rotatably supported by an axle 32 and rotates by the rotation of a hand rim. A wheel hub 383 is attached to the axle 32 and rotates by the rotation of the hand rim base part 39. A coil spring 40 is interposed between the hand rim base part 39 and the wheel hub 383, and biases the hand rim base part 39 or the wheel hub 383 in a direction of eliminating the relative displacement according to the operation force of the hand rim. An attenuation device 6 is interposed between the hand rim base part 39 and the wheel hub 383, and attenuates the biasing force of the coil spring 40 in a direction of generating resistance.

Description

  The present invention relates to a wheel of an electric wheelchair having a small battery, and more particularly to a wheelchair wheel provided with an input sensor for detecting an input of a motor and a hand rim.

  The wheelchair includes a frame, a seat, wheels, and a handle. The seat is attached to the frame. The wheels are attached to the frame. An annular hand rim is attached to the wheel. The wheel rotates when the occupant seated on the seat operates the hand rim. In such a wheelchair, a large force is required to rotate the wheel by operating the hand rim. For example, when moving a wheelchair over a long period of time or when moving on a slope, the occupant is significantly tired.

  Wheelchairs with attached batteries, motors and J / S controllers are used. In such a wheelchair, electric power is supplied from the battery to the motor by the occupant operating the J / S controller. The motor is rotated by the electric power from the battery, and the wheelchair moves. In a wheelchair equipped with a battery and a motor, fatigue when moving the wheelchair can be greatly reduced. However, in such a wheelchair, all the power necessary for movement is supplied from the motor. In such a wheelchair, a large-capacity battery is attached in preparation for driving the motor for a long time. Therefore, the weight of the entire wheelchair becomes heavy and it is difficult to lift the wheelchair. In such a wheelchair, for example, it is difficult to lift the wheelchair and put it on a car.

  In order to prevent an increase in the weight and size of the wheelchair and to reduce the labor required for the operation of the wheelchair, a wheelchair having a small battery and a motor has been considered. In this wheelchair, a part of the power required for movement is supplied from the motor as the passenger's hand rim is operated. In this wheelchair, the wheelchair moves by the power supplied from the motor in addition to the force with which the occupant operates the hand rim (see Patent Document 1).

  A wheelchair that can be assisted by a motor is provided with a configuration for detecting an operation of a passenger's hand rim. In the wheelchair described in Patent Document 1, the wheel includes a wheel hub and a hand rim base. Spokes are fixed to the wheel hub. A hand rim is fixed to the hand rim base. The wheel hub and the hand rim base can be rotated relative to each other. The wheel hub and the hand rim base are arranged side by side in the axial direction. The wheel hub includes a guide member that guides the expansion and contraction direction of the coil spring and a pair of stoppers that support both ends of the coil spring in the axial direction. The hand rim base portion includes a pair of stoppers disposed at both ends in the axial direction of the coil spring. When the hand rim base portion rotates relative to the wheel hub, the pair of stoppers rotate in the circumferential direction as the hand rim base portion rotates. For this reason, the coil spring is compressed by one of the pair of stoppers of the hand rim base portion and one of the pair of stoppers of the wheel hub. At this time, the hand rim base portion rotates relative to the wheel hub. In the wheelchair of Patent Document 1, relative rotation of the hand rim base portion with respect to the wheel hub is detected by a sensor. In the wheelchair of Patent Document 1, when the relative rotation of the hand rim base portion with respect to the wheel hub is detected, it is determined that the hand rim has been operated by the occupant. When an occupant's hand rim operation is detected, power for rotating the wheel is supplied from the motor. Further, the wheel is rotated by the power transmitted from the hand rim base portion to the wheel hub and the power supplied from the motor via the coil spring.

JP 09-215713 A

  When the hand rim is rotated forward, the direction in which the hand rim base portion is displaced relative to the wheel hub in the direction in which the wheelchair is moved forward is defined as the first rotation direction, and the reverse direction is defined as the second rotation direction. In the wheelchair of Patent Document 1, the wheel hub stopper and the hand rim base portion stopper overlap each other in the circumferential direction when the hand rim operating force is not applied. In the wheelchair of Patent Document 1, for example, when the hand rim is strongly displaced in the forward direction, the hand rim base portion is largely displaced in the first rotation direction with respect to the wheel hub. Thereafter, when the occupant releases his hand from the hand rim, the hand rim base portion is displaced in the second rotational direction with respect to the wheel hub by the elastic force of the coil spring. At this time, due to the elastic force of the coil spring and the inertial force of the hand rim base part, the hand rim base part may further rotate in the second rotational direction and vibrate around the neutral point rather than the position where the stoppers overlap in the circumferential direction. . In this case, the motor supplies the wheel with power to advance the wheelchair backward. Since a force in the direction opposite to the traveling direction is applied or an unintended assisting force is applied, smooth running is hindered.

  In order to solve the above problem, for example, it is conceivable to dispose a friction member such as a sponge between the wheel hub and the hand rim base. In such a configuration, friction occurs when the hand rim base portion swings with respect to the wheel hub. For this reason, in the above configuration, the hand rim base portion is less likely to be displaced from the neutral point where the wheel hub stopper and the hand rim base portion stopper overlap in the circumferential direction with respect to the wheel hub.

  Friction members such as sponges vary greatly in frictional force depending on the usage environment and the degree of deterioration. When a friction member such as a sponge is arranged between the wheel hub and the hand rim base as described above, the damping force for attenuating the vibration of the hand rim base with respect to the wheel hub is unstable. In the above configuration, a friction member such as a sponge wears during rotation of the hand rim base portion with respect to the wheel hub, and therefore needs to be frequently replaced.

  An object of the present invention is to provide a wheel that can give a stable resistance force to a hand rim base portion that swings with respect to a wheel hub and has a small maintenance burden such as replacement of members.

Means for Solving the Problems and Effects of the Invention

  The electric assist wheel according to the present invention is detachable from a wheelchair. The electric assisting wheel includes an axle, a hand rim, a hand rim base member, a wheel hub, an elastic member, and a damping device. The hand rim base member is rotatably supported on the axle and is rotationally displaced along with the rotational displacement of the hand rim. The wheel hub is attached to the axle and is rotationally displaced with the rotational displacement of the hand rim base member. The elastic member is interposed between the hand rim base member and the wheel hub, and urges the elastic member in a direction that eliminates relative displacement according to the operating force of the hand rim. The damping device is interposed between the hand rim base member and the wheel hub, and attenuates in a direction in which resistance is generated against the biasing force of the elastic member.

  In the wheel described above, the hand rim base member is relatively displaced with respect to the wheel hub as the passenger operates the hand rim. At this time, the elastic member is elastically deformed by the elastic member support portion between the hand rim base member and the wheel hub. The force that the occupant rotates the hand rim is transmitted from the hand rim base member to the wheel hub via the elastic member. At this time, the motor generates a driving force according to the displacement angle of the hand rim with respect to the wheel hub. The wheel is rotated by the driving force of the motor and the force that rotates the hand rim of the passenger. Thereafter, when the occupant releases his / her hand from the handle, the elastic member that has been elastically deformed generates a force to restore the original shape. Due to the action of the force, the hand rim is reversely rotated and the damping device applies a damping force to the hand rim in a direction to stop the rotation of the hand rim according to the displacement speed of the hand rim.

  Here, when the hand rim base member is displaced relative to the wheel hub, the damping device applies a damping force to the hand rim according to the rotational displacement speed of the hand rim. For this reason, a stable damping force acts on the hand rim in accordance with the displacement speed of the hand rim. Therefore, there is almost no resistance force for slow input displacement as in the case of occupant's hand rim operation, no force is input, and the damping force is effective in the direction to attenuate the vibration of the hand rim only when returning by the force of the elastic member. Generated automatically. Since the resistance force is generated by the damping device, it is not necessary to frequently perform maintenance such as replacing the friction member.

  In the wheel for electric assist according to another aspect of the present invention, the hand rim base member is attached to the wheel hub via a bearing.

  Here, the hand rim base member is easy to rotate with respect to the wheel hub. For this reason, the hand rim can be rotationally displaced with a small force.

  In the electric assist wheel according to another aspect of the present invention, the hand rim base member is arranged side by side with the wheel hub in the axial direction. The wheel hub is formed with support surfaces including end surfaces located at both ends in the circumferential direction and the radial direction of the elastic member. The hand rim base member is formed with a support portion including end surfaces positioned at both ends in the circumferential direction of the elastic member, overlapping the support surface in the circumferential direction.

  Here, when the hand rim base portion is rotationally displaced with respect to the wheel hub, the elastic member is compressed by the support surface and the support portion. When the occupant releases his hand from the hand rim, the hand rim base member is rotationally displaced in the opposite direction with respect to the wheel hub by the elastic member.

  In the electric assist wheel according to another aspect of the present invention, the wheel hub has a plurality of support surfaces formed at equal intervals in the circumferential direction. The hand rim base member has a plurality of support portions arranged at equal intervals in the circumferential direction. The attenuation device is disposed between two support surfaces and support portions adjacent to each other in the circumferential direction.

  Here, since the attenuation device is disposed between the two adjacent support portions and the support surface, the attenuation device can be disposed at a position overlapping the hand rim base member and the wheel hub in the axial direction. For this reason, the width | variety of a wheel can be made thin.

  In the electric assist wheel according to another aspect of the present invention, the damping device is fixed to either the hand rim base portion or the wheel hub, and the gear plate on which the gear teeth are formed, and the hand rim base member or the wheel hub. And a gear formed with gear teeth fixed to the other and meshing with the gear teeth of the gear plate. The damping device applies a damping force that reduces the rotational speed of the gear.

  Here, when the hand rim base member and the wheel hub are relatively rotated, the gear is rotated by the gear plate. By applying a damping force that reduces the rotational speed of the gear by the damping device, the gear is easily stopped.

  In the electrically assisted wheel according to another aspect of the present invention, the damping device includes a case in which a fluid is stored. A damping force that reduces the rotational speed of the gear is applied to the gear by the fluid.

  For example, when the rotational speed of the gear is attenuated using a friction member such as a sponge, the friction member is worn and frequent maintenance is required. Here, since the rotational speed of the gear can be reduced by the fluid, the maintenance burden can be reduced as compared with the case where the rotational speed of the gear is attenuated by using a friction member such as a sponge.

  In the electrically assisted wheel according to another aspect of the present invention, the damping device is disposed at substantially the same position as the elastic member in the radial direction.

1 is an overall left side view of a wheelchair according to the present invention. 1 is an overall rear view of a wheelchair. It is a partial left view which shows the whole wheel. FIG. 4 is an overall cross-sectional view taken along line AA in FIG. 3. It is a whole sectional view of a power unit and a hub. It is a partial expanded sectional view of the circumference | surroundings of a motor. It is a whole component figure which shows a rotor. It is a whole component figure which shows a stator. It is a side view of a power unit in the state where a case cover was removed. It is a partial expanded sectional view of the circumference | surroundings of a hand rim base part. It is the whole hub side view showing the hub of the state where the wheel cover was removed in the state where the hand rim is not operated from the outside. It is the elements on larger scale of FIG. 11 which shows the circumference | surroundings of a coil spring. It is JJ sectional drawing of FIG. It is a partial expanded side view which shows the circumference | surroundings of the coil spring of the state which the hand rim base part displaced with respect to the wheel hub. It is the elements on larger scale of FIG. 11 which shows the circumference | surroundings of a damping mechanism. It is a partial expanded sectional view which shows the periphery of a rotational displacement detection mechanism. It is component drawing of an annular magnet. It is component drawing of an annular plate. It is a side view of a power unit in the state where a wheel hub was removed. It is the elements on larger scale of FIG. 18 which shows the circumference | surroundings of a detection element. It is the schematic which shows the positional relationship of the annular magnet and annular plate in the state where the hand rim is not operated. It is the schematic which shows the positional relationship of the annular magnet and annular plate in the state by which the hand rim was most operated. It is a figure which shows the wheel in the state in which the hand rim is not rotating relatively with respect to a wheel hub. It is a figure which shows the wheel in the state which the hand rim rotated relatively with respect to the wheel hub. It is the elements on larger scale of FIG. 24 which shows the circumference | surroundings of a damping mechanism. It is a figure which shows the change of the voltage at the time of converting the detection result by a detection element into an electrical signal.

  Hereinafter, a wheelchair 1 according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description of the members will not be repeated. Hereinafter, the arrow F in the figure indicates the forward direction of the wheelchair 1. An arrow U in the figure indicates the upward direction of the wheelchair 1. An arrow R in the figure indicates the right direction of the wheelchair 1. An arrow L in the figure indicates the left direction of the wheelchair 1.

<Overall configuration of wheelchair>
FIG. 1 is an overall left side view of a wheelchair 1 according to the present invention. In the following description, the front, rear, left, and right directions indicate the front, rear, left, and right directions as viewed from the occupant seated on the seat of the wheelchair 1. The center in the vehicle width direction means the center of the width of the vehicle body in the horizontal direction when viewed from the front. The vehicle width direction outer side means a direction toward the right side or a direction toward the left side from the center in the vehicle width direction. The inside in the vehicle width direction means a direction from the right side or the left side of the vehicle body toward the center in the vehicle width direction.

  The wheelchair 1 includes a pair of left and right body frames 2, a pair of left and right rear wheels 3, a battery 4, and a pair of left and right front wheels 5. Since FIG. 1 is a side view, one body frame 2, one rear wheel 3, and one front wheel 5 appear. The vehicle body frame 2 includes a handle 21, a handle support frame 22, a seat support frame 23, a footboard support frame 24 and a front wheel support frame 25. The handle 21 is gripped when a person other than the passenger operates the wheelchair 1. The handle 21 is located above the rear wheel 3. A part of the handle support frame 22 extends in the vertical direction. The seat support frame 23 supports a seat on which an occupant is seated. The seat support frame 23 is inclined downward from the front to the rear. One end of the seat support frame 23 is fixed to the handle support frame 22. A footboard support frame 24 is provided at the other end of the seat support frame 23. The footboard support frame 24 is disposed in front of the front wheel 5. A footboard (not shown) is attached to the footboard support frame 24. The front wheel support frame 25 is located above the front wheel 5. The front wheel support frame 25 supports the front wheel 5 rotatably.

  The rear wheel 3 is supported by the body frame 2. The rear wheel 3 is supported by the handle support frame 22. The battery 4 supplies electric power to the power source of the rear wheel 3. A part of the battery 4 is disposed behind the vehicle body frame 2. A part of the battery 4 is located above the upper end of the rear wheel 3. The front wheel 5 has a smaller diameter than the rear wheel 3.

  FIG. 2 is an overall rear view of the wheelchair 1. The wheelchair 1 includes a seat 26 and a backrest 27. The seat 26 and the backrest 27 are disposed between the pair of left and right body frames 2. The seat 26 is disposed between a pair of left and right seat support frames 23. The backrest 27 is disposed between the pair of left and right handle support frames 22. The backrest 27 supports the back of an occupant seated on the seat 26 of the wheelchair 1. Between the left rear wheel 3 and the battery 4 and the right wheel, there is a cable 28 including a cable for supplying electric power from the battery 4 to the power source of the left and right rear wheels 3 and a signal line for transmitting information on the left and right wheels. Has been placed. The rear wheel 3 includes a hand rim 31. The hand rim 31 is operated when the occupant advances the wheelchair 1. When the hand rim 31 is operated by the occupant, the rear wheel 3 rotates integrally with the hand rim 31. The hand rim 31 is disposed outside the rear wheel 3 in the vehicle width direction.

  FIG. 3 is a left side view showing the left rear wheel 3. In the following description, the radially inner side means a direction from the outer periphery of the wheel toward the center in a side view. The radially outer side means a direction from the center of the wheel toward the outer periphery of the wheel. The circumferential direction means a direction along the circumference around the axle.

  The rear wheel 3 includes a hub 33, a spoke 34, a rim 35, a tire 36, a hand rim 31, and a connection pipe 37. The hub 33 is disposed at the center of the rear wheel 3 in a side view. The spoke 34 is a wire-like member. A plurality of spokes 34 are disposed between the rim 35 and the hub 33. The rim 35 is disposed on the radially outer side of the spoke 34 in a side view. The rim 35 is annular in a side view. The tire 36 is disposed outside the rim 35 in the radial direction. The tire 36 is attached to the rim 35. The tire 36 is annular in a side view. The hand rim 31 is disposed on the radially inner side of the tire 36 in a side view. The hand rim 31 is disposed radially inward of the tire 36. The hand rim 31 is annular in a side view. A connection pipe 37 is disposed between the hand rim 31 and the hub 33. Three connection pipes 37 are arranged at equal intervals in the circumferential direction.

  FIG. 4 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a front cross-sectional view at a position passing through the axle 32 of the left rear wheel 3. In the following description, the axial direction means the direction in which the axle 32 extends. For convenience of explanation, in the following explanation, the side supported by the vehicle body frame 2 will be described as the axially inner side of the rear wheel 3, and the direction away from the vehicle body frame 2 in the axial direction will be described as the axially outer side of the rear wheel 3.

  The rear wheel 3 includes an axle 32. One end of the axle 32 is fixed to the handle support frame 22. The axle 32 extends in the left-right direction when viewed from the front. The hub 33 is attached to the outside of the housing including the axle 32. The spoke 34 is attached to the outer peripheral surface of the hub 33. A rim 35 is disposed at one end outside the spoke 34 in the radial direction. The hand rim 31 is disposed outside the rim 35 in the axial direction substantially parallel to the rim 35.

  FIG. 5 is an enlarged front sectional view of the hub 33. The hub 33 includes a hand rim base portion 39 and a wheel hub 383. A part of the power unit 38 is disposed inside the wheel hub 383. The power unit 38 includes a motor 381, a speed reduction mechanism 382, and a battery 4 (see FIG. 2 and the like).

  The motor 381 is disposed substantially at the center of the axle 32 in the axial direction. A speed reduction mechanism 382 is disposed on the right side of the motor 381. The speed reduction mechanism 382 transmits the power output from the motor 381 to the wheel hub 383. The speed reduction mechanism 382 includes a gear train 384.

  A wheel hub 383 is disposed on the right side of the speed reduction mechanism 382. The wheel hub 383 is attached to the axle 32 via a bearing 383a. The wheel hub 383 can rotate relative to the axle 32. Spokes 34 are fixed to the outer periphery of the wheel hub 383.

  FIG. 6 is a partially enlarged front view of the power unit 38. The power unit 38 includes a housing 331. The housing 331 includes a first housing 332, a second housing 333, and a case cover 334. A space B is formed between the first housing 332 and the second housing 333. In the space B, a motor 381 is accommodated. The case cover 334 forms a space C between the first housing 332 and the case cover 334. In the space C, a control board 336 and a speed reduction mechanism 382 are arranged. The first housing 332 is disposed inside the case cover 334 in the axial direction. The case cover 334 is fixed to the first housing 332 with bolts 335. A second housing 333 is fixed to the first housing 332. The second housing 333 is a flat plate case. The axle 32 is fixed to the housing 331 in such a structure that the axle 32 is sandwiched between the second housing 333 and the support plate 500.

  The motor 381 includes a rotor 381a and a stator 381b. The rotor 381a is rotatable relative to the axle 32. The rotor 381a includes a motor shaft 381c, a support plate 381d, and a magnet 381e. The motor shaft 381c is rotatably supported on the axle 32. The support plate 381d is fixed to the axially inner end of the motor shaft 381c. The support plate 381d is disposed in the vicinity of the second housing 333. The magnet 381e is fixed to the support plate 381d. The magnet 381e is disposed with a predetermined gap from the stator 381b in the axial direction. The stator 381b is fixed to the first housing 332. The stator 381b is not rotatable relative to the axle 32.

  The speed reduction mechanism 382 includes a first gear 382a, a second gear 382b, a third gear 382c, a fourth gear 382h, and a transmission gear 383g. The first gear 382a is fixed to the outer periphery of the motor shaft 381c. The second gear 382b is arranged outside the first gear 382a in the radial direction. The second gear 382b meshes with the first gear 382a. The second gear 382b is rotatably attached to the shaft 382d via a bearing 382e. The shaft 382d is fixed to the first housing 332 and the support plate 500. The third gear 382c is disposed outside the second gear 382b in the radial direction. The shaft 382f of the third gear 382c is rotatably supported by the first housing 332 and the support plate 500 via a bearing 382g. The third gear 382c rotates integrally with the shaft 382f. The third gear 382c meshes with the second gear 382b. The third gear 382c has a larger diameter than the second gear 382b. The fourth gear 382h is fixed to the shaft 382f. The transmission gear 383g meshes with the fourth gear 382h.

  FIG. 7 is a component diagram of the rotor 381a. The back yoke 381d of the rotor 381a is a disk-shaped member centered on the motor rotation shaft. The back yoke 381d has three holes 381j formed between the motor shaft 381c and the magnet 381e in the radial direction. The magnet 381e is an annular member. The magnet 381e has magnetic poles arranged side by side in the circumferential direction. In the magnet 381e, the N pole and the S pole are alternately magnetized in the circumferential direction.

  FIG. 8 is a component diagram of the stator 381b. The stator 381b includes a stator core 381f. A plurality of teeth 381h are formed on the stator 381b. The plurality of teeth 381h are arranged at equal intervals in the circumferential direction. A coil (not shown) is wound around the tooth 381h.

  FIG. 9 is a side view of the power unit 38 with the bolt 335 (see FIG. 6) removed and the case cover 334 and the support plate 500 removed from the housing 331. FIG. The first gear 382a, the second gear 382b, and the third gear 382c included in the speed reduction mechanism 382 are arranged side by side on a straight line. The first gear 382a, the second gear 382b, and the third gear 382c are disposed from the radially inner side toward the outer side.

  FIG. 10 is a partially enlarged view of the hub 33 showing a configuration around the hand rim base portion 39. The hand rim base portion 39 is attached to the axle 32 via a wheel hub 383. A wheel hub 383 is disposed outside the case cover 334 in the axial direction. A hand rim base portion 39 is disposed on the outer side in the axial direction of the wheel hub 383. The wheel hub 383 is rotatably attached to the axle 32 via a bearing 383a. A nut 383b is provided on the outer side in the axial direction of the bearing 383a. The position of the wheel hub 383 in the axial direction is determined by the nut 383b. A cover 383c is provided outside the nut 383b in the axial direction so that the nut 383b cannot be seen from the outside of the hub 33. The wheel hub 383 can rotate relative to the axle 32. The outer peripheral end of the wheel hub 383 is bent toward the inner side in the axial direction to form a cylindrical portion 383e. The spoke 34 is fixed to the cylindrical portion 383e. A spring holding surface 383 f is formed on the wheel hub 383. A coil spring 40 is disposed on the spring holding surface 383f. The spring holding surface 383 f is a columnar surface along the shape of the coil spring 40. A spring cover 383j is fixed to the wheel hub 383. The spring cover 383j is fixed to the wheel hub 383 with screws 383k. The spring cover 383 j covers the coil spring 40 from the outside in the axial direction with respect to the axial direction of the axle 32. A columnar support surface 383p is formed on the spring cover 383j along a part of the shape of the coil spring 40. The coil spring 40 includes a large spring 401 and a small spring 402. A small spring 402 is disposed inside the large spring 401. The coil spring 40 biases the hand rim base portion 39 or the wheel hub 383 in a direction that eliminates relative displacement according to the operating force of the hand rim 31. The wheel hub 383 includes a transmission gear 383g. A fourth gear 382 h is formed on the shaft 382 f of the third gear 382 c of the speed reduction mechanism 382. The transmission gear 383g meshes with the fourth gear 382h. The transmission gear 383g is located inside the fourth gear 382h in the radial direction. The wheel hub 383 is provided with an arrangement space 383n of the damping device 6 located on the radially outer side of the transmission gear 383g.

  The hand rim base portion 39 is attached to the wheel hub 383 via a bearing 391 so as to be swingable. One end on the radially inner side of the connection pipe 37 is fixed to the hand rim base portion 39. For this reason, when the hand rim 31 (see FIG. 2) is rotated, the hand rim base portion 39 is displaced. A spring support portion 392 is formed on the hand rim base portion 39. The spring support portion 392 is disposed between the spring cover 383j and the spring holding portion 383f in the axial direction of the axle 32. A coil spring 40 is disposed on the spring support portion 392. A wheel cover 393 is attached to the outer side of the hand rim base portion 39 in the axial direction. The hand rim base portion 39 is provided with an arrangement space 395 for the damping device 6 outside the bearing 391 in the radial direction.

  The damping device 6 is arranged in the arrangement space 383 n of the wheel hub 383 and the arrangement space 395 of the hand rim base portion 39. The damping device 6 is disposed at a position overlapping the third gear 382c of the speed reduction device 382 in the radial direction. The damping device 6 generates a damping force on the hand rim base portion 39 in a direction in which resistance is generated with respect to the biasing force of the coil spring 40. The damping device 6 is disposed on the outer side in the axial direction of the fourth gear 382h. The damping device 6 applies a damping force that reduces the rotational speed of the hand rim base 39 when the hand rim base 39 rotates with respect to the wheel hub 383. The damping device 6 applies a damping force corresponding to the rotational speed of the hand rim base portion 39 to the hand rim base portion 39. The damping device 6 applies a resistance force to the hand rim base portion 39 in a direction that prevents the hand rim base portion 39 from rotating relative to the wheel hub 383. The damping device 6 includes a gear plate 61 and a damper device 62.

  FIG. 11 is an overall left side view of the hub 33 showing the hub 33 with the wheel cover 393 and the cover 383c removed. In FIG. 11, the configuration of the connection pipe 37 and the hand rim 31 is omitted for convenience of explanation.

  The spring holding surface 383f of the wheel hub 383 and the spring support portion 392 of the hand rim base portion 39 are located at the same position in the circumferential direction and the radial direction. Three spring holding surfaces 383f and spring support portions 392 are arranged side by side at equal intervals in the circumferential direction. An arc-shaped through hole 383m and an arc-shaped groove 383q are provided on the radially inner side of the spring holding surface 383f of the wheel hub 383. The through hole 383m is formed in the groove 383q. The groove 383q extends along the circumferential direction. In the radial direction, an annular groove 39 a is formed on the inner side of the spring support portion 392 of the hand rim base portion 39. The annular groove 39a is disposed at a position overlapping the through hole 383m and the groove 383q in the radial direction. An annular plate 50 is disposed in the annular groove 39a. The annular plate 50 is fixed to the hand rim base portion 39 with bolts 51. The bolt 51 is disposed on a boss portion 51a formed on the hand rim base portion 39 inside the groove 383q. A pin 394 is disposed inside the groove 383q and the through hole 383m.

  The damping device 6 is disposed between two adjacent coil springs 40 in the circumferential direction. The gear plate 61 is fixed to the wheel hub 383 by a pair of screws 61a. The damper device 62 is disposed on the radially outer side of the gear plate 61. The damper device 62 includes a case 621, a gear 622, a gear shaft 623, and a mounting plate 624. The attachment plate 624 is fixed to the hand rim base portion 39 with screws 62a.

  FIG. 12 is a partially enlarged view of FIG. FIG. 12 is an enlarged view of the periphery of the coil spring 40. A pair of sliders 403 are disposed at both ends of the coil spring 40. The slider 403 is a cylindrical member having a disc-shaped bottom 403a at one end. A large coil spring 401 and a small coil spring 402 are disposed on the inner peripheral side of the two sliders 403 disposed to face each other. The spring holding surface 383f and the support surface 383p of the spring cover 383j are formed in a columnar shape as described above. For this reason, a substantially cylindrical space is formed by the spring holding surface 383f and the spring cover 383j. The slider 403 can slide in the columnar space. The support surface 383p includes an end surface 383s corresponding to the bottom of the cylinder. The spring holding surface 383f includes an end surface 383h corresponding to the bottom of the cylinder. A part of the bottom 403a of the slider 403 is in contact with the end surface 383h of the spring holding surface 383f. Another portion of the bottom 403a of the slider 403 is in contact with the end surface 383s of the support surface 383p. Another portion of the bottom 403 a of the slider 403 is in contact with the support end 392 a of the spring support 392. For this reason, the coil spring 40 has its front-rear rotational position in the circumferential direction determined as a neutral point by the support end 392a of the spring support portion 392, the end surface 383s of the support surface 383p, and the end surface 383h of the spring holding surface 383f.

  A boss portion 51 a is formed around the bolt 51. A boss 51b is arranged at a position symmetrical to the boss 51a with the pin 394 interposed therebetween. The boss part 51 a and the boss part 51 b are formed integrally with the hand rim base part 39.

  13 is a cross-sectional view taken along line JJ in FIG. In FIG. 13, for the convenience of explanation, detailed configurations of the wheel hub 383, the hand rim base 39, the coil spring 40, and the spring cover 383j are omitted. The bottom 403a of the slider 403 is in contact with the wheel hub 383, the hand rim base portion 39, and the spring cover 383j in order from the inner side to the outer side in the axial direction of the axle 32 (from the left to the right in the drawing). The outer surface of the slider 403 in the axial direction of the axle 32 is in contact with the support surface 383p of the spring cover 383j. The inner surface of the slider 403 in the axial direction of the rotation axis (left and right direction of the paper surface) is in contact with the spring holding surface 383 f of the wheel hub 383. For this reason, the position of the coil spring 40 in the axial direction (the left-right direction on the paper surface) is determined by the support surface 383p of the spring cover 383j and the spring holding surface 383f of the wheel hub 383.

  FIG. 14 is a partially enlarged side view showing a state around the coil spring 40 when the hand rim base portion 39 is rotationally displaced with respect to the wheel hub 383. In FIG. 14, the hand rim base portion 39 is rotated in the direction of the arrow P. FIG. 14 shows a state in which the hand rim base portion 39 is rotating with respect to the wheel hub 383 up to a point where the boss portion 51a around the bolt 51 contacts the edge of the arc-shaped groove 383q. In this state, a slight space is provided between the pin 394 and the edge of the through hole 383m, and the pin 394 is not in contact with the edge of the through hole 383m. When the hand rim base portion 39 rotates by a predetermined amount in the direction of the arrow P, the boss portion 51a contacts the edge of the groove 383q. For this reason, the hand rim base part 39 cannot rotate in the direction of arrow P from the state of FIG. Similarly, when the hand rim base portion 39 is rotated in the direction opposite to the arrow P, the hand rim base portion 39 cannot rotate beyond the point where the boss portion 51b contacts the edge of the groove 383q. Thus, the relative rotation of the hand rim base portion 39 and the wheel hub 383 is limited to a predetermined range by the groove 383q, the boss portion 51a, and the boss portion 51b. When the hand rim base portion 39 rotates backward (in the direction of arrow P) with respect to the wheel hub 383 from the state of FIG. 12, the support end 392a of the spring support portion 392, the end surface 383h of the spring holding surface 383f, and the end surfaces of the support surface 383p The distance to 383s is reduced. Thus, the coil spring 40 is compressed by the support end 392a of the spring support portion 392, the end surface 383h of the spring holding surface 383f, and the end surface 383s of the support surface 383p.

  FIG. 15 is a partially enlarged view of FIG. FIG. 15 is an enlarged view of the periphery of the attenuation device 6. The gear plate 61 includes a plate base 611 and a gear 612 that is a part of a cylindrical gear. The plate base 611 is located on the radially inner side with respect to the gear 612. The gears 612 and 622 formed on the gear plate 61 constitute a gear mesh. Oil is stored inside the case 621 of the damper device 62. The gear 622 is disposed on the inner side in the axial direction of the case 621. The gear shaft 623 of the gear 622 is parallel to the axle 32 (see FIG. 10). A part of the gear shaft 623 is disposed inside the case 621. When the gear shaft 623 rotates, the oil in the case 621 is agitated and resistance is generated with respect to the gear shaft 623. The damper device 62 applies a damping force to the gear 622 by a mechanism similar to that of an oil damper used in a motorcycle or the like.

  For example, when the hand rim base portion 39 and the wheel hub 383 are relatively rotationally displaced, the gear 622 rotates with respect to the gear plate 61. At this time, the agitation resistance of the oil stored in the case 621 increases according to the speed of the gear 622. As the oil is stirred, a damping force acts on the gear 622. In accordance with the damping force, the amplitude of vibration centered on the neutral point of the hand rim 31 is attenuated.

  The support plate 500, the wheel hub 383, and the hand rim base portion 39 are provided with a rotational displacement detection mechanism 41 that detects the rotation of the hand rim base portion 39 with respect to the power unit 38. Below, the structure of the rotational displacement detection mechanism 41 is demonstrated with reference to FIG.

  FIG. 16 is a partially enlarged front view of the hub 33 showing the periphery of the rotational displacement detection mechanism 41. The rotational displacement detection mechanism 41 includes an annular magnet 42, an annular plate 43, and a detection element 44. The annular magnet 42 is attached to the wheel hub 383 by screws 421. The annular magnet 42 is disposed inside the transmission gear 383g in the radial direction. The inner diameter of the annular plate 43 is located inside the annular magnet 42 in the radial direction (see the upper side in FIG. 16). A part of the annular plate 43 is disposed at a position overlapping the annular magnet 42 in the radial direction (see the lower side in FIG. 16). The annular plate 43 is integrated with a pin 394 fitted to the plate 50 fixed to the hand rim base portion 39 with bolts 51. For this reason, the annular plate 43 rotates with respect to the power unit 38 together with the hand rim base portion 39. The pin 394 passes through the wheel hub 383 in the axial direction. The detection element 44 is a so-called Hall element. The detection element 44 can detect magnetism. The detection element 44 converts the detected magnetism into an electrical signal and outputs it to the control unit. The detection element 44 is fixed to the support plate 500. The detection element 44 is located inside the annular plate 43 in the axial direction. The detection element 44 is located inside the annular magnet 42 and the annular plate 43 in the radial direction. A metal plate 441 is disposed outside the detection element 44 in the axial direction. The metal plate 441 overlaps a part of the annular plate 43 in the radial direction. For this reason, the detection element 44 does not directly detect the magnetism from the annular magnet 42 but detects the magnetism via the annular plate 43 and the metal plate 441. The magnetism detected by the detection element 44 is output to the control unit as an electrical signal.

  FIG. 17 is a component diagram of the annular magnet 42. In the annular magnet 42, S poles 422 and N poles 423 are alternately arranged in the circumferential direction. The annular magnet 42 is provided with nine S poles 422 and N poles 423. The annular magnet 42 is attached to the fixed plate 424. The fixing plate 424 is a member for fixing the annular magnet 42 to the wheel hub 383. The fixing plate 424 has holes 425 (mounting holes and knock holes). When the annular magnet 42 is attached to the wheel hub 383, a knock pin is inserted into the knock hole and fixed with a screw 421 (see FIG. 16).

  FIG. 18 is a component diagram of the annular plate 43. The annular plate 43 includes a base 431 and nine protrusions 432. The base 431 is annular. The base 431 is disposed at a position overlapping the metal plate 441 in the radial direction (see FIG. 16). In the radial direction, the width of the base portion 431 is narrower than the width of the protrusion 432. The protrusion 432 extends outward from the base 431 in the radial direction. The protrusions 432 are arranged at equal intervals in the circumferential direction. Nine protrusions 432 are arranged in the circumferential direction at intervals of 40 °. The protrusion 432 is disposed at a position overlapping the annular magnet 42 in the radial direction.

  FIG. 19 is an overall side view of the power unit 38 with the case cover 334 removed from the power unit 38. A two-dot chain line D in FIG. 19 indicates a first direction in which the gears of the speed reduction mechanism 382 are arranged. A two-dot chain line G indicates a line that passes through the center of the rear wheel 3 and extends in a direction orthogonal to the two-dot chain line D in the plane on which the rear wheel 3 is disposed. Two detection elements 44 are fixed around the axle 32. A direction in which the damping mechanism 382 extends is defined as a first direction (two-dot chain line D). The pair of detection elements 44 are arranged at substantially symmetrical positions across the two-dot chain line D in the front-rear direction (left-right direction in the drawing).

  20 is a partially enlarged view of FIG. FIG. 20 shows the periphery of a pair of detection elements 44. A line passing through one detection element 44a and the center of the axle 32 is defined as a line K. A line passing through the other detection element 44b and the center of the axle 32 is defined as a line L. The sum of the angle E formed by the line K and the first direction D and the angle F formed by the line L and the first direction D is 140 ° (= E + F).

  Since the pair of detection elements 44 are arranged at an interval of 140 °, for example, when the N pole 423 of the annular magnet 42 is located on the axially outer side of one detection element 44a, the other detection is performed. The S pole 422 of the annular magnet 42 is disposed outside the element 44b in the axial direction (see FIG. 17). The voltage of the electric signal output from each detection element 44a, 44b is added in the control unit. For example, in a state where the protrusion 432 is positioned on the outer side in the axial direction of one detection element 44a, the other detection element 44b is positioned in the middle of the adjacent protrusion 432 when viewed from the outer side in the axial direction (see FIG. 18). (See position Q).

  FIG. 21 is a schematic diagram showing the positional relationship between the annular magnet 42 and the annular plate 43 in a state where the annular plate 43 is not rotating with respect to the annular magnet 42 (a state where the hand rim 31 is not operated). As shown in FIG. 21, when the hand rim 31 is not operated by the occupant, the axially outer side of the protrusion 432 (the back side of the paper in FIG. 21) is located between the N pole 423 and the S pole 422. Yes. In this state, the magnetism of the N pole 423 moves to the S pole 422 through the protrusion 432. At this time, since the magnetism does not pass through the base 431, the magnetism is not detected by the detection element 44. When the hand rim 31 is operated by the occupant, the hand rim base portion 39 is rotationally displaced relative to the wheel hub 383. The pin 394 (see FIG. 15) is rotationally displaced along with the rotational displacement of the hand rim base portion 39. The annular plate 43 is rotationally displaced relative to the annular magnet 42 by the rotational displacement of the pin 394. When the operating force of the hand rim 31 is increased and the boss 51a of the bolt 51 is in contact with the edge of the groove 383q (see FIG. 14), the positional relationship between the annular magnet 42 and the annular plate 43 is as shown in FIG. And change. FIG. 22 shows a state where the annular plate 43 is rotated about 5 degrees in the clockwise direction in FIG. 21 with respect to the annular magnet 42. At this time, the protrusion 432 is located closer to the N pole 423 than the S pole 422. For this reason, a part of the magnetism of the N pole 423 passes through the base 431 and is detected by the detection element 44.

  In the wheelchair 1, the detection results detected by the two detection elements 44 are added by the control unit. The control unit determines the output of the motor 381 based on the calculation result obtained by adding the two detection results.

<Operation>
FIG. 23 shows the hub 33 with the wheel cover 393 and the cover 383c removed in a state where no force is applied to the hand rim 31 from the outside. In FIG. 23, the spokes 34, the tires 36, etc. are omitted. When the occupant rotates the hand rim 31 backward (clockwise in FIG. 23) from the state of FIG. 23, the hand rim base 39 rotates clockwise in FIG. 23 about the axle 32 as the hand rim 31 rotates. (See FIG. 24). The hand rim base portion 39 is rotationally displaced in the direction of the arrow H. At this time, as shown in FIG. 24, the coil spring 40 is compressed by the support end 392a of the spring support portion 392, the end surface 383s of the support surface 383p, and the end surface 383h of the spring holding surface 383f. That is, the state changes from the state of FIG. 12 to the state of FIG. In this state, an angular displacement (rotational displacement) according to the operating force of the hand rim 31 occurs. Here, the hand rim base portion 39 is rotatable with respect to the wheel hub 383 until the pin 394 fixed to the hand rim base portion 39 contacts the edge of the arc-shaped through hole 383 m provided in the wheel hub 383. . In a state where the coil spring 40 is compressed, a part of the force of the occupant operating the hand rim 31 is transmitted from the hand rim 31 to the wheel hub 383 via the connection pipe 37, the hand rim base portion 39 and the coil spring 40.

  At this time, as shown in FIG. 25, the gear 622 moves forward with the rotation of the hand rim base portion 39 in the arrow H direction. The gear 622 is rotated by the gear plate 61 in the clockwise direction (the direction of the arrow H) in the side view of the hub 33. According to the rotation of the gear 622, the oil stored in the case 611 and the hand rim base 39 according to the speed of the hand rim base 39 in the counterclockwise direction (direction of arrow M) in the side view of the hub 33. Resistance. For this reason, the rotational speed of the hand rim base 39 is reduced.

  Next, an operation for detecting a relative rotational displacement of the hand rim base portion 39 with respect to the wheel hub 383 will be described. When the hand rim 31 is rotated by the occupant, the hand rim base portion 39 rotates with respect to the wheel hub 383 until the boss portion 51a of the bolt 51 contacts the edge of the groove 383q. The hand rim base portion 39 rotates relative to the wheel hub 383 by an angle corresponding to the operating force. At this time, the annular plate 43 (see FIGS. 16 and 18) rotates around the axle 32 and is displaced relative to the annular magnet 42. When the annular plate 43 rotates relative to the annular magnet 42, the protrusion 432 moves in the circumferential direction on the inner side in the axial direction of the annular magnet 42 (change from the state of FIG. 21 to the state of FIG. 22). As the protrusion 432 moves, the magnetism detected by the detection element 44 changes. Based on the change in magnetism detected by the detection element 44, the relative rotational displacement of the hand rim base portion 39 with respect to the wheel hub 383 is detected. At this time, the detection element 44 detects a change in magnetism due to the rotational displacement of the annular magnet 42 and the annular plate 43. The magnetism detected by the detection element 44 is converted into an electrical signal and then output to the control unit.

  The detection result of the detection element 44 is output to the control unit. The control unit determines the output of the motor 381 based on the relative rotation amount of the hand rim base unit 39 with respect to the wheel hub 383. When the output of the motor 381 is determined, electric power is supplied from the battery 4 to the coil of the stator 381b. When electric power is supplied to the coil of the stator 381b, the rotor 381a rotates with respect to the stator 381b. When the rotor 381a rotates, the motor shaft 381c rotates. The first gear 382a is rotated by the rotation of the motor shaft 381c. When the first gear 382a rotates, power is transmitted to the wheel hub 383 via the second gear 382b, the third gear 382c, the fourth gear 382h, and the transmission gear 383g (FIG. 10). Thus, the wheelchair 1 is moved by the resultant force of the power from the motor 381 and the force for operating the hand rim 31 of the passenger.

  Thereafter, when the occupant releases his hand from the hand rim 31, the coil spring 40 rotates the hand rim base portion 39 in the direction of arrow M in FIG. 24 with respect to the wheel hub 383. At this time, the gear 622 moves backward. The gear 622 is rotated backward in the direction of arrow M by the gear plate 61. At this time, the damping force acts on the hand rim base portion 39 to reduce the rotational speed of the hand rim base portion 39 with respect to the wheel hub 383. For this reason, in the wheelchair 1, it can suppress that the hand rim base part 39 rotates in the arrow M direction exceeding the state of FIG.

  When the wheelchair 1 moves by operating the hand rim 31 by the occupant, the rear wheel 3 continues to rotate for a while by the power from the motor 381 and the power based on the occupant operating the hand rim 31. At this time, the annular magnet 42 and the annular plate 43 are in the state shown in FIG. However, there are attachment intersections in each member such as the hand rim base 39 and the wheel hub 383. For this reason, even when the hand rim berth portion 39 and the wheel hub 383 rotate integrally, the detection element 44 detects magnetism because the annular plate 43 is slightly displaced with respect to the annular magnet 42. The magnetism detected by the detection element 44 is called magnetic noise.

  For example, in a state where the hand rim base portion 39 and the wheel hub 383 are integrally rotated with respect to the power unit 38, the annular magnet 42 and the annular plate 43 are rotated together in the positional relationship of FIG. In this state, magnetic noise is detected in each of the detection elements 44a and 44b. FIG. 26 shows an example of the voltage when the detection result of the detection element 44 is converted into an electric signal when magnetic noise is detected. The vertical axis represents voltage. The horizontal axis indicates time. FIG. 26A shows the voltage of an electric signal based on the detection result of one detection element 44a. FIG. 26B shows the voltage of the electric signal based on the detection result of the other detection element 44b. As shown in FIGS. 26 (a) and 26 (b), the electrical signal based on the detection result of one of the detection elements 44 and the electrical signal based on the detection result of the other detection element 44 are inverted in phase. Yes. Therefore, when the two are added together, the waveform is completely cancelled. For this reason, even if it is a case where magnetic noise is detected by the detection element 44, it can prevent that detection accuracy falls.

  Even when the hand rim 31 is being operated, magnetic noise may be detected due to wheelchair vibration or the like. However, as described above, the magnetic noise can be canceled by adding the result of the detection element 44. it can. FIG. 26 is an example, and the same detection result as that in FIG. 26 is not always obtained.

<Features of this embodiment>
The wheelchair 1 described in the above embodiment includes the damping device 6 that applies a damping force corresponding to the operation speed of the hand rim base portion 39 to the hand rim base portion 39. For this reason, in the damping device 6, the damping force is not configured to fluctuate depending on use, such as wear of the friction member. Therefore, the damping force can be stably applied to the hand rim 31. Since a damping force is applied to the hand rim 31 from the damping device 6, it is not necessary to replace the friction member more frequently than when a friction member is disposed between the wheel hub 383 and the hand rim base portion 39, for example. In addition, the neutral point does not vary due to friction.

  In the wheelchair 1 described above, the hand rim 31 including the hand rim base portion 39 is attached to the wheel hub 383 via a bearing 391. For this reason, the hand rim base portion 39 can be rotated with respect to the wheel hub 383 with a smaller force than when a friction member is attached between the hand rim base portion 39 and the wheel hub 383. Therefore, when the occupant releases his hand from the hand rim 31, the state shown in FIG.

  In said wheelchair 1, the damping device 6 is arrange | positioned between the coil springs 40 adjacent in the circumferential direction. For example, when the damping device 6 is arranged at a position overlapping the coil spring 40 in the circumferential direction, the damping device 6 and the coil spring 40 are arranged side by side in the axial direction. Since the damping device 6 and the coil spring 40 can be disposed at the same position in the axial direction, the width in the axial direction can be reduced.

  The motor 381 attached to the wheel 3 after being attached to the wheelchair 1 described in the above embodiment does not protrude from the surface of the power unit 38. For this reason, it can attach to the frame of various shapes compared with the structure where the motor is extended in the vehicle width direction of a wheel.

  In the rear wheel 3 attached to the wheelchair 1 described in the above embodiment, the rotational displacement detection mechanism 41 is arranged in an annular shape around the axle 32. For this reason, the axial width of the power unit 38 can be reduced as compared with the case where the mechanism for detecting the relative rotation between the wheel hub 383 and the hand rim base 39 has a configuration extending in the axial direction. For this reason, the vehicle width of the wheelchair 1 can be made small.

[Other Embodiments]
(1) Although the axial gap type motor is used as the motor in the wheelchair 1 of the above embodiment, the present invention is not limited to this. For example, a radial gap motor may be used as the motor.

  (2) In the wheelchair 1 of the above embodiment, the damping device 6 is a device using an oil damper configuration, but the present invention is not limited to this. In the present invention, other configurations such as a magnetic damper may be used as the damping device.

  (3) In the wheelchair 1 of the above embodiment, the hand rim base portion 39 is connected to the wheel hub 383 via the bearing 391, but the present invention is not limited to this. The hand rim base portion 39 may be connected to the wheel hub 383 in a state in which the hand rim base portion 39 is easy to rotate relative to the wheel hub 383. For example, sufficient oil may be filled between the hand rim base portion 39 and the wheel hub 383.

DESCRIPTION OF SYMBOLS 1 Wheelchair 2 Body frame 3 Rear wheel 6 Damping device 31 Hand rim 32 Axle 33 Hub 34 Spoke 35 Rim 36 Tire 37 Connection pipe 38 Power unit 39 Hand rim base part 40 Coil spring 61 Gear plate 62 Damper device 381 Motor 382 Deceleration mechanism 383 Wheel hub 383f Spring holding surface 383g Transmission gear 392 Spring support

Claims (8)

An electric assist wheel that can be attached to and detached from a wheelchair,
The axle,
With hand rims,
A hand rim base member that is rotatably supported by the axle and that is rotationally displaced in accordance with the rotational displacement of the hand rim;
A wheel hub attached to the axle and rotationally displaced with rotational displacement of the hand rim base member;
An elastic member interposed between the hand rim base member and the wheel hub and biasing in a direction to eliminate relative displacement according to the operating force of the hand rim;
A damping device that is interposed between the hand rim base member and the wheel hub and attenuates in a direction in which resistance is generated against the biasing force of the elastic member;
With
Electric assist wheel. The electrically assisted wheel according to claim 1,
The hand rim base member is attached to the wheel hub via a bearing;
Electric assist wheel. The electrically assisted wheel according to claim 1 or 2,
The hand rim base member is arranged side by side in the axial direction with the wheel hub,
The wheel hub is formed with support surfaces including end surfaces located at both ends in the circumferential direction and the radial direction of the elastic member,
The hand rim base member is formed with a support portion including end surfaces positioned at both ends in the circumferential direction of the elastic member, overlapping the support surfaces at both ends in the circumferential direction.
Electric assist wheel. The electrically assisted wheel according to claim 2 or 3,
The wheel hub is formed with a plurality of support surfaces at equal intervals in the circumferential direction,
In the hand rim base member, a plurality of the support portions are arranged at equal intervals in the circumferential direction,
The attenuation device is disposed between two support surfaces and support portions adjacent to each other in the circumferential direction.
Electric assist wheel. The electrically assisted wheel according to claim 4,
The attenuation device comprises:
A gear plate fixed to either the wheel hub or the hand rim base member and having gear teeth formed thereon;
A gear tooth fixed to either the hand rim base member or the wheel hub and formed with gear teeth meshing with the gear teeth of the gear plate,
The damping device applies a damping force to reduce the rotational speed of the gear;
Electric assist wheel. The electric assist wheel according to claim 5,
The attenuation device includes a case in which a fluid is stored,
A damping force that reduces the rotational speed of the gear is applied to the gear by the fluid.
Electric assist wheel. The electric assist wheel according to claim 6,
The damping device is arranged at the same position as the elastic member in the radial direction.
Electric assist wheel. A wheelchair provided with the wheel according to any one of claims 1 to 7.

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