JP2016133176A - Electric assist device and hand driving movable body using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric assist device which switches assist of a motor between a functioning state and a stop state and achieves reduction in costs and weight.SOLUTION: An electric assist device includes: motors 21, each of which rotates a driving shaft 23A; wheels 13, each of which is provided at outer periphery part of the driving shaft 23A so as to rotate relative to the driving shaft 23A; and friction plates 24, each of which may be switched between an assist state, in which the friction plate 24 transmits a rotation force of the driving shaft 23A to the wheel 13, and a free state, in which the friction plate 24 interrupts transmission of the rotation force of the driving shaft 23A to the wheel 13. In the free state, the driving shaft 23A is functioned as a fixed shaft for freely rotating the wheel 13.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electric assist device applied to a push-motion moving body such as a silver car, a stroller, a shopping cart, a rehabilitation walking car, a carriage, and the like, and a push-motion moving body using the same.

  2. Description of the Related Art Conventionally, wheelchairs are electrically driven with wheels that are driven to rotate by a motor.

  In such an electric wheelchair, the rotation of the motor is normally transmitted to the wheel, and when the driving force by the motor is unnecessary, the connection between the motor and the wheel is cut off so that the rotation of the motor is not transmitted to the wheel. Some have a clutch mechanism (see, for example, Patent Documents 1 and 2).

JP 2005-69351 A International Publication No. 2012/046395

  However, the clutch mechanisms disclosed in Patent Documents 1 and 2 are complicated in structure and costly. In addition, since the clutch mechanism is complicated, a portion that connects the rotating shaft of the motor and the rotating shaft of the wheel is increased in size or weight.

  Assistance by a motor is also being considered for a hand-carried moving body such as a silver car that assists walking by pushing an elderly person while leaning on it. In the case of these hand-carrying moving bodies, cost reduction, weight reduction, and size reduction are desired. Even if a conventional clutch mechanism for a wheelchair is applied to such a hand-pushing moving body, it is difficult to reduce the cost, the weight, and the size.

  Accordingly, an object of the present invention is to provide an electric assist device capable of reducing the cost, the weight and the size of the electric assist device while being able to switch the on / off of the assist by the motor, and a hand moving body using the electric assist device. That is.

The present invention employs the following means in order to solve the above problems.
That is, the electric assist device of the present invention includes a motor that rotates a drive shaft, a wheel that is provided on an outer peripheral portion of the drive shaft and that is rotatable relative to the drive shaft, and the wheel that is driven by the drive shaft. A power transmission mechanism that can be switched between an assist state for transmitting the rotational force of the shaft and a free state for interrupting transmission of the rotational force of the drive shaft to the wheels, and in the free state, the drive shaft The wheel functions as a fixed shaft for freely rotating the wheel.

  According to such a configuration, the drive shaft can be used as the drive shaft as it is during the assist rotation in which the wheel is rotated using the rotational force of the motor, and the drive shaft as the fixed shaft when the wheel is rotated freely. Available. That is, the drive shaft can have two functions, and it is possible to switch the assist on / off by the motor with a simple structure. For this reason, the electric assist device can be reduced in cost, weight, and size.

  An electric assist device according to the present invention includes a motor that rotates a drive shaft, a wheel that is rotatably supported on a cylindrical portion formed on an outer peripheral side of the drive shaft on the outer peripheral surface of the motor, and the wheel A power transmission mechanism capable of switching between an assist state for transmitting the rotational force of the drive shaft and a free state for interrupting transmission of the rotational force of the drive shaft to the wheels, and in the free state, the cylindrical shape The portion is made to function as a fixed shaft for freely rotating the wheel.

  Thus, by making the cylindrical portion function as a fixed shaft for freely rotating the wheel, separately from the drive shaft, it is possible to switch the intermittent assist of the motor with a simple structure. For this reason, the electric assist device can be reduced in cost, weight, and size.

  In the electric assist device of the present invention, the power transmission mechanism is provided so as to be movable along the axial direction of the drive shaft, and is between a first position in the assist state and a second position in the free state. And a transfer mechanism that is movably provided, and a moving mechanism that moves the transfer member between the first position and the second position.

  According to such a configuration, the rotation of the drive shaft is transmitted to the wheel with respect to the transmission member by moving the transmission member to the first position that transmits the rotation of the drive shaft to the wheel. In other words, at the first position, the drive shaft and the wheel rotate together by the driving force of the motor. Further, when the transmission member is moved to the second position, the transmission of the rotation of the drive shaft to the wheel by the transmission member is released. In this state, since the wheel is rotatably supported on the outer peripheral portion of the drive shaft, the wheel can be rotated independently of the drive shaft. Thereby, the driving force of the motor is not transmitted to the wheels, and the assist by the motor can be released. For this reason, the presence or absence of transmission of the driving force of the motor can be easily switched. In addition, as a configuration for enabling switching between the intermittent assist of the motor, it is sufficient to include a transmission member and a moving mechanism for moving the transmission member between the first position and the second position, and a simple configuration. It becomes.

  In the electric assist device of the present invention, an abutting portion that abuts against the transmission member is formed on the wheel, the transmission member is plate-shaped, and the first position that abuts against the abutting portion by the moving mechanism; and You may make it move along the axial direction of the said drive shaft between said 2nd positions spaced apart from the contact part.

  According to such a configuration, when the plate-shaped transmission member is abutted against the abutting portion, the driving force of the motor is transmitted to the wheel via the transmission member by the frictional force generated between the transmission member and the abutting portion. be able to.

  The abutting portion and the transmission member may each have a tapered contact surface whose diameter gradually decreases from the second position toward the first position.

  Furthermore, the transmission member may have an outer peripheral portion that abuts against the abutting portion.

  Thus, a large torque can be efficiently transmitted to a wheel because the transmission member hits the abutting portion at the outer peripheral portion.

  Moreover, the hand-held moving body of the present invention includes the above-described electric assist device.

  According to such a configuration, it is possible to switch ON / OFF of assist by the electric assist device with a simple configuration.

  According to the present invention, it is possible to easily switch the presence or absence of transmission of the driving force of the motor with a simple configuration. For this reason, it is possible to reduce the cost, the weight, and the size of the motor while it is possible to switch between assists by the motor.

It is a perspective view which shows an example of the hand-pushing moving body provided with the electric assist apparatus in embodiment of this invention. In the electric assist device according to the first embodiment of the present invention, it is a half cross-sectional view in a state where transmission of driving force is released. FIG. 3 is a half cross-sectional view in a state where a driving force is transmitted in the electric assist device of FIG. 2. In the electric assist device according to the second embodiment of the present invention, FIG. FIG. 5 is a half cross-sectional view in a state where a driving force is transmitted in the electric assist device of FIG. 4. In the electric assist device according to the third embodiment of the present invention, FIG. In 3rd Embodiment of this invention, it is a half sectional view in the state which transmits a driving force. In the electric assist device according to the fourth embodiment of the present invention, it is a half cross-sectional view in a state where transmission of driving force is released. In 4th Embodiment of this invention, it is a half sectional view in the state which transmits a driving force.

  Next, an electric assist device according to an embodiment of the present invention and a manually-moving body using the same will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view illustrating an example of a hand-pushing moving body including an electric assist device according to an embodiment of the present invention. FIG. 2 is a half cross-sectional view of the electric assist device according to the first embodiment of the present invention in a state where transmission of driving force is released. FIG. 3 is a half cross-sectional view of the electric assist device of FIG. 2 in a state where the driving force is transmitted.

(Electric assist silver car)
As shown in FIG. 1, the electrically assisted silver car (hand-held moving body) 10 includes a frame 11, a storage portion 12, and wheels 13.

The frame 11 includes a seat frame 11a that supports the storage unit 12, a back frame 11b that is provided at one end of the seat frame 11a and extends upward, and a leg frame 11c that extends downward from the seat frame 11a. And comprising.
Here, in the following description, in a plan view, the side on which the back frame 11b is provided with respect to the seat frame 11a is the rear side, the opposite side is the front side, and the left and right sides are sideways in the front-rear direction. Sometimes called.

  The storage unit 12 includes an article storage unit 12a that can store articles and the like therein, and a base unit 12b that covers the upper side of the article storage unit 12a and on which an article can be placed or seated. ing.

The wheel 13 is provided at the lower end of the leg frame 11c. The wheel 13 includes a wheel 13h and a tire 13t attached to the outer periphery of the wheel 13h.
In this embodiment, the leg frame 11c extends from the upper side to the lower side toward the four corners of the electrically assisted silver car 10 in a plan view. Thus, the wheels 13 are arranged at the four corners of the electrically assisted silver car 10. Here, of the four wheels 13, two wheels 13f provided on both sides in the width direction in front of the frame 11 are provided in pairs on both sides of the leg frame 11c. Further, the wheels 13r provided on both sides in the width direction behind the frame 11 are provided on the side of the leg frame 11c.

  The electrically assisted silver car 10 includes, for example, an electrically assisted mechanism that rotationally drives the wheels 13r on both sides in the rear width direction. The electric assist mechanism includes a drive unit (electric assist device) 20A (see FIGS. 2 and 3) that rotationally drives the wheel 13, a control unit 30 that is housed in the housing unit 12 and controls the operation of the drive unit 20A, It has.

(Drive unit)
As shown in FIGS. 2 and 3, the drive unit 20 </ b> A includes a motor 21, a speed reducer 22, a drive shaft 23 </ b> A, a friction plate (transmission member) 24, an urging member (movement mechanism) 25, and a pressing member. (Moving mechanism) 26.

  The motor 21 is provided on the side of the leg frame 11c shown in FIG. The motor 21 receives power from a battery (not shown) stored in the storage unit 12 together with the control unit 30, and an output shaft (not shown) is rotationally driven. The motor 21 is integrally formed with a cylindrical support sleeve (cylindrical portion) 21 s that protrudes on the opposite side of the leg frame 11 c, that is, outward in the width direction W of the electrically assisted silver car 10.

  The reducer 22 decelerates the rotation of the output shaft of the motor 21 at a predetermined reduction ratio and transmits it to the drive shaft 23A. Here, the speed reducer 22 includes an appropriate speed reduction mechanism such as a planetary gear mechanism. The speed reducer 22 is provided inside the support sleeve 21s.

The drive shaft 23A includes a large diameter portion 23a and a small diameter portion 23b. The large diameter portion 23a has a disk shape and is formed on the drive shaft 23A on the speed reducer 22 side. The large-diameter portion 23a is rotatably provided inside the support sleeve 21s via a bearing 27.
The small diameter portion 23b has an outer diameter smaller than that of the large diameter portion 23a. The small diameter portion 23b is provided so as to protrude from the inner side of the support sleeve 21s toward the outer side W in the width direction of the electric assist silver car 10 with respect to the large diameter portion 23a.

  A wheel 13h constituting the wheel 13r is fitted on the outer peripheral side of the small diameter portion 23b via a bearing 28. A spacer 31 is provided between the bearing 28 and the large diameter portion 23a of the drive shaft 23A. Thereby, the wheel 13r is disposed concentrically with the drive shaft 23A, and is provided rotatably with respect to the drive shaft 23A. The wheel 13 h is integrally provided with a cylindrical portion (butting portion) 29 that protrudes outward in the width direction of the electrically assisted silver car 10. A tapered surface 29t is formed on the inner peripheral edge portion of the tip portion 29s of the cylindrical portion 29. The tapered surface 29t gradually increases in inner diameter as it goes outward in the width direction W of the electric assist silver car 10.

The friction plate 24 has a disk shape whose outer diameter is larger than that of the small diameter portion 23b. The friction plate 24 is supported so as to be movable along the central axis direction with respect to the small diameter portion 23b of the drive shaft 23A. For example, the friction plate 24 is attached to a spline shaft portion 23p formed in the small-diameter portion 23b, and can reciprocate within a certain dimension along the central axis direction of the spline shaft portion 23p. It is impossible to rotate relative to the portion 23p.
In the outer peripheral portion of the friction plate 24, a tapered surface 24t whose outer diameter gradually decreases toward the motor 21 side is formed on the outer peripheral edge portion on the motor 21 side.

  The urging member 25 urges the friction plate 24 toward the outer side W in the width direction of the electrically assisted silver car 10. As such an urging member 25, a spring member or the like can be appropriately employed. In this embodiment, as the urging member 25, a leaf spring having an annular shape and having an outer peripheral side 25b protruding outward in the width direction of the electric assist silver car 10 with respect to the inner peripheral side 25a is used. Such an urging member 25 is provided between the bearing 28 and the friction plate 24 via an annular thrust plate 32.

  As shown in FIG. 2, the urging member 25 has an inner peripheral side 25 a in contact with the bearing 28 and an outer peripheral side 25 b through a thrust plate 32 when the friction plate 24 is not pressed by a pressing member 26 described later. The friction plate 24 is urged toward the outside W in the width direction of the electrically assisted silver car 10. In this state, the taper surface 29t formed on the wheel 13h and the taper surface 24t of the friction plate 24 face each other with a gap C therebetween, and are brought into a non-contact state.

  The pressing member 26 presses the friction plate 24 toward the motor 21 side. The pressing member 26 includes a base member 33, a sliding contact member 34, and a lever member 35.

  The base member 33 is integrally provided on the friction plate 24 on the outer side W in the width direction of the electrically assisted silver car 10.

  The slidable contact member 34 is provided integrally with the base member 33, and has a slidable contact surface 34f that slidably contacts along a cam surface 35f of a lever member 35 described later.

  The lever member 35 is rotatably provided around a rotation shaft 36 provided integrally with the small diameter portion 23b of the drive shaft 23A. The lever member 35 is integrally provided with a cam surface 35f and an operation lever 35r. The cam surface 35f is formed on the outer peripheral surface of the lever member 35, and is formed such that the radius from the center of the rotation shaft 36 gradually increases along the circumferential direction. The operation lever 35r of the lever member 35 is formed to extend toward the outer peripheral side, and the lever member 35 rotates around the rotation shaft 36 by operating the operation lever 35r.

  Such a lever member 35 rotates around the rotation shaft 36 by operating the operation lever 35r. When the lever member 35 is turned in a direction in which the radius from the center of the rotation shaft 36 gradually increases on the cam surface 35f, the sliding surface 34f of the sliding member 34 is pressed against the cam surface 35f. Thereby, as shown in FIG. 3, the friction plate 24 slides to the motor 21 side together with the sliding contact member 34 and the base member 33, and the tapered surface 24t of the friction plate 24 abuts against the tapered surface 29t of the wheel 13h. At this time, the urging member 25 is pressed and elastically deformed while being sandwiched between the thrust plate 32 and the large diameter portion 23a of the drive shaft 23A.

  By operating the lever member 35, a “free state” in which the rotational force of the motor 21 is not transmitted to the wheels 13 and an “assist state” in which the rotational force of the motor 21 is transmitted to the wheels 13 to assist the traveling of the electrically assisted silver car 10. Can be switched.

(Free state)
In the free state, the lever member 35 does not press the friction plate 24 by the cam surface 35f. In this state, the friction plate 24 is positioned at the second position P2 where the tapered surface 24t faces the tapered surface 29t formed on the wheel 13h with a gap C therebetween and is in a non-contact state.
In this state, the drive shaft 23A of the motor 21 and the wheel 13 are independent of each other. Since the wheel 13 is supported on the drive shaft 23A via the bearing 28, the wheel 13 is rotatable around the drive shaft 23A. That is, the drive shaft 23A functions as a fixed shaft that pivotally supports the wheel 13, and the wheel 13 rotates smoothly when the user manually pushes the electrically assisted silver car 10.

(Assist state)
In the assist state, when the lever member 35 is operated to press the slidable contact surface 34f of the slidable contact member 34 against the cam surface 35f, the friction plate 24 has a tapered surface 24t that abuts against the tapered surface 29t of the wheel 13h. Located at position P1. Then, the friction plate 24 and the wheel 13h rotate integrally by the frictional force generated between the tapered surfaces 24t and 29t. That is, as a result, the rotational force of the motor 21 is transmitted to the wheels 13 and the traveling of the electrically assisted silver car 10 can be assisted.
When shifting to the assist state, the control unit 30 may control the motor 21 to operate after detecting that the lever member 35 has been operated.

(effect)
According to the present embodiment, the friction plate 24 is moved to the first position P <b> 1 that transmits the rotation of the drive shaft 23 </ b> A to the wheel 13, so that the rotation of the drive shaft 23 </ b> A is directed toward the wheel 13. Is transmitted to. That is, at the first position P1, the wheel 13 rotates integrally with the drive shaft 23A by the driving force of the motor 21.
When the friction plate 24 is moved to the second position P2 so as to be separated from the wheel 13, the transmission of the rotation of the drive shaft 23A to the wheel 13 by the friction plate 24 is released. Thereby, the driving force of the motor 21 is not transmitted to the wheel 13, and the assist by the motor 21 can be released. In other words, the drive shaft 23A and the wheel 13 are arranged concentrically, and when the motor 21 is driven to drive the wheel 13 (in the assist state), the drive shaft 23A is used as a shaft for driving the wheel 13 to rotate. On the other hand, when the wheel 13 is freely rotated (free state), the drive shaft 23 </ b> A functions as a fixed shaft that pivotally supports the wheel 13.

  Moreover, the presence or absence of the assist by the motor 21 can be easily switched. In addition, as a configuration for switching presence / absence of the assist, it is sufficient if the friction plate 24 and the pressing member 26 for moving the friction plate 24 are provided, and the configuration is simple. Therefore, it is possible to reduce the cost, the weight, and the size of the motor 21 while the assist of the motor 21 can be switched.

  Further, if the plate-like friction plate 24 is abutted against the cylindrical portion 29, the driving force of the motor 21 is generated via the friction plate 24 by the friction force generated between the friction plate 24 and the cylindrical portion 29. Can be transmitted reliably.

  Further, the cylindrical portion 29 and the friction plate 24 have tapered surfaces 24t and 29t. Furthermore, the friction plate 24 has an outer peripheral portion that abuts against the cylindrical portion 29. As described above, the friction plate 24 abuts against the cylindrical portion 29 at the outer peripheral portion, whereby a large torque can be efficiently transmitted to the wheel 13.

(Second Embodiment)
Next, a description will be given of a second embodiment of the electric assist device according to the present invention and a hand-pushing moving body using the same. Note that in the second embodiment described below, the same reference numerals in the drawing denote the same components as in the first embodiment, and a description thereof will be omitted (the same applies to the following embodiments).
FIG. 4 is a half cross-sectional view of the electric assist device according to the second embodiment of the present invention in a state where transmission of driving force is released. FIG. 5 is a half cross-sectional view in the state where the driving force is transmitted in the electric assist device of FIG. 4.

  In the present embodiment, the electrically assisted silver car 10 includes, for example, an electrically assisted mechanism that rotationally drives the wheels 13r on both sides in the rear width direction. The electric assist mechanism includes a drive unit (electric assist device) 20B that rotationally drives the wheel 13, and a control unit 30 that is housed in the housing unit 12 and controls the operation of the drive unit 20B.

  4 and 5, the drive unit 20B includes a motor 21, a speed reducer 22, a drive shaft 23B, a friction plate (transmission member) 44, an urging member (movement mechanism) 45, and a pressing member. 26.

  The motor 21 is provided on the side of the leg frame 11c shown in FIG. The motor 21 is integrally formed with a cylindrical support sleeve 21 s that protrudes on the side opposite to the leg frame 11 c, that is, outward in the width direction W of the electrically assisted silver car 10.

  The speed reducer 22 is provided inside the support sleeve 21s.

The drive shaft 23B includes a large diameter portion 23a and a small diameter portion 23b. The large-diameter portion 23a is rotatably provided inside the support sleeve 21s via a bearing 27.
The small diameter portion 23b is provided so as to protrude from the inner side of the support sleeve 21s toward the outer side W in the width direction of the electric assist silver car 10 with respect to the large diameter portion 23a.

  A wheel 13 h is fitted on the outer peripheral side of the support sleeve 21 s of the motor 21 via a bearing 48. As a result, the wheel 13r is arranged concentrically with the drive shaft 23B and is rotatably provided to the motor 21. The wheel 13 h is integrally provided with a cylindrical portion (abutting portion) 41 that protrudes outward in the width direction of the electrically assisted silver car 10. The tip 41s of the cylindrical portion 41 protrudes outward in the width direction W of the electrically assisted silver car 10 from the support sleeve 21s. A tapered surface 41t whose inner diameter gradually increases toward the outer side W in the width direction of the electrically assisted silver car 10 is formed on the inner peripheral edge of the tip portion 41s of the cylindrical portion 41.

The friction plate 44 has a disk shape whose outer diameter is larger than that of the small diameter portion 23b. The friction plate 44 is supported so as to be movable along the central axis direction with respect to the small diameter portion 23b of the drive shaft 23B. For example, the friction plate 44 is attached to a spline shaft portion 23p formed in the small-diameter portion 23b, and can reciprocate within a range of a certain dimension along the central axis direction of the spline shaft portion 23p. It is impossible to rotate relative to 23p.
In the outer peripheral portion of the friction plate 44, a tapered surface 44t whose outer diameter gradually decreases toward the motor 21 side is formed on the outer peripheral edge portion on the motor 21 side.

The urging member 45 urges the friction plate 44 toward the outside W in the width direction of the electrically assisted silver car 10. As such an urging member 45, a spring member or the like can be appropriately employed. In this embodiment, as the urging member 45, a leaf spring is used that is annular and whose outer peripheral side 45b protrudes outward in the width direction of the electric assist silver car 10 with respect to the inner peripheral side 45a. However, not only the leaf spring but also various spring members such as a coil spring can be appropriately employed. Further, it is sufficient that the friction plate 44 can be urged toward the outer side W in the width direction of the electrically assisted silver car 10. For example, an air damper or the like can be employed.
The biasing member 45 of this embodiment is provided between the large-diameter portion 23a of the drive shaft 23B and the friction plate 44 via an annular thrust plate 42.

  As shown in FIG. 4, in the state where the friction plate 44 is not pressed by the pressing member 26, the urging member 45 has the inner peripheral side 45 a in contact with the bearing 48 and the outer peripheral side 45 b through the thrust plate 42. 44 is urged toward the outside W in the width direction of the electrically assisted silver car 10. In this state, the taper surface 41t formed on the wheel 13h and the taper surface 44t of the friction plate 44 face each other with a gap C therebetween, and are brought into a non-contact state.

  The pressing member 26 presses the friction plate 44 toward the motor 21 side. The pressing member 26 includes a base member 33, a sliding contact member 34, and a lever member 35.

  The base member 33 is integrally provided on the friction plate 44 on the outer side W in the width direction of the electrically assisted silver car 10.

  The slidable contact member 34 is provided integrally with the base member 33, and has a slidable contact surface 34f that slidably contacts along a cam surface 35f of a lever member 35 described later.

  The lever member 35 is rotatably provided around a rotation shaft 36 provided integrally with the small diameter portion 23b of the drive shaft 23B. The lever member 35 is integrally provided with a cam surface 35f and an operation lever 35r.

  Such a lever member 35 rotates around the rotation shaft 36 by operating the operation lever 35r. When the lever member 35 is rotated in a direction in which the radius from the center of the rotation shaft 36 in the cam surface 35f gradually increases, the sliding contact surface 34f of the sliding contact member 34 is pressed against the cam surface 35f. As a result, as shown in FIG. 5, the friction plate 44 slides toward the motor 21 together with the sliding contact member 34 and the base member 33, and the tapered surface 44t of the friction plate 44 abuts against the tapered surface 41t of the wheel 13h. At this time, the urging member 45 is pressed and elastically deformed while being sandwiched between the thrust plate 42 and the large diameter portion 23a of the drive shaft 23B.

  By operating the lever member 35, a “free state” in which the rotational force of the motor 21 is not transmitted to the wheels 13 and an “assist state” in which the rotational force of the motor 21 is transmitted to the wheels 13 to assist the traveling of the electrically assisted silver car 10. Can be switched.

(Free state)
In the free state, the lever member 35 does not press the friction plate 44 by the cam surface 35f. In this state, the friction plate 44 is positioned at the second position P2 where the tapered surface 44t faces the tapered surface 41t formed on the wheel 13h with a gap C therebetween and is in a non-contact state.
In this state, the wheel 13 is rotatably supported by the support sleeve 21 s via the bearing 48. In other words, the support sleeve 21s functions as a fixed shaft for freely rotating the wheel 13.

(Assist state)
In the assist state, when the lever member 35 is operated to press the sliding contact surface 34f of the sliding contact member 34 against the cam surface 35f, the tapered surface 44t of the friction plate 44 abuts against the tapered surface 41t of the wheel 13h. Thus, the friction plate 44 and the wheel 13h rotate integrally by the frictional force generated between the tapered surfaces 44t and 29t. That is, as a result, the rotational force of the motor 21 is transmitted to the wheels 13 and the traveling of the electrically assisted silver car 10 can be assisted.

(effect)
According to this embodiment, since the wheel 13 is rotatably supported by the support sleeve 21s formed in the motor 21, it can rotate independently of the drive shaft 23B. In such a configuration, the presence or absence of transmission of the driving force from the motor 21 to the wheel 13 can be easily switched by moving the friction plate 24. In addition, it is sufficient to provide the friction plate 24 and the pressing member 26, and the configuration is simple. As described above, it is possible to reduce the cost and the weight while switching the intermittent assist by the motor 21.

  The wheel 13 is rotatably supported by a support sleeve 21 s formed on the motor 21. Therefore, it is not necessary to support the wheel 13 with the drive shaft 23B. Thereby, compared with the said 1st Embodiment, it becomes possible to shorten the drive shaft 23B, and the drive unit 20B can be reduced in size and thickness.

(Third embodiment)
Next, a description will be given of a third embodiment of the electric assist device according to the present invention and a hand-held movable body using the same.
FIG. 6 is a half cross-sectional view of the electric assist device according to the third embodiment of the present invention in a state where transmission of driving force is released. FIG. 7 is a half cross-sectional view in the state where the driving force is transmitted in the electric assist device of FIG. 6.

  As shown in FIGS. 6 and 7, the difference between the first embodiment and the third embodiment is that the configuration for transmitting the driving force from the drive shaft 23 </ b> A to the wheel 13 is different. That is, the drive unit (electric assist device) 20C of the third embodiment includes a transmission plate 344 and connecting pins 311 and 312 in place of the friction plate 24, the urging member 25, and the pressing member 26 of the first embodiment. ing.

  More specifically, the transmission plate 344 is provided on the distal end side of the drive shaft 23A so as to rotate integrally with the drive shaft 23A. The transmission plate 344 includes a disk-shaped plate main body 344a and a flange portion 344b integrally provided on the outer side W in the width direction of the plate main body 344a.

  The outer diameter of the plate body 344a is set slightly smaller than the inner diameter of the cylindrical portion 29 provided on the wheel 13h. And it arrange | positions in the radial direction inner side of the cylindrical part 29 so that relative rotation with respect to this cylindrical part 29 is possible. On the other hand, the outer diameter of the flange portion 344 b is set to be approximately the same as the outer diameter of the cylindrical portion 29. The flange portion 344b has an end surface 344c facing the axial end surface 29u of the cylindrical portion 29 in the axial direction with a gap C1 therebetween. Further, the thickness of the plate body 344a is set to be thicker than the thickness of the flange portion 344b.

Here, an insertion recess 344d into which the connecting pin 311 can be inserted is formed on the outer peripheral surface of the plate body 344a. On the other hand, the cylindrical portion 29 is formed with a through hole 29v that penetrates in the radial direction and into which the connecting pin 311 can be inserted at a position corresponding to the insertion recess 344d.
The flange portion 344b is formed with a through hole 344e that penetrates in the axial direction and into which the connecting pin 312 can be inserted. On the other hand, an insertion recess 29w into which the connecting pin 312 can be inserted is formed in the cylindrical portion 29 at a position corresponding to the through hole 344e.

With this configuration, as shown in FIG. 6, when the connecting pin 311 is inserted into the insertion recess 344d and the through hole 29v, and the connection pin 312 is inserted into the insertion recess 29w and the through hole 344e, the transmission plate 344 The wheel 13h is connected. Thus, the “assist state” is established in which the rotational force of the motor 21 is transmitted to the wheels 13 to assist the traveling of the electrically assisted silver car 10.
On the other hand, as shown in FIG. 7, when the connecting pin 311 is removed from the insertion recess 344d and the through hole 29v, and the connection pin 312 is removed from the insertion recess 29w and the through hole 344e, the transmission plate 344 and the wheel 13h are connected. Canceled. As a result, a “free state” in which the rotational force of the motor 21 is not transmitted to the wheel 13 is set. That is, the drive shaft 23 </ b> A functions as a fixed shaft that pivotally supports the wheel 13.

(effect)
Therefore, according to the above-described third embodiment, in addition to the same effects as those of the above-described first embodiment, the drive unit 20C having a simpler structure than the drive unit 20A of the first embodiment can be obtained. it can.
In the third embodiment described above, the case where the two connecting pins 311 and 312 are provided has been described. However, the present invention is not limited to this, and only one of the two connecting pins 311 and 312 may be provided.

(Fourth embodiment)
Next, a description will be given of a fourth embodiment of an electric assist device according to the present invention and a hand-pushing moving body using the same.
FIG. 8 is a half cross-sectional view of the electric assist device according to the fourth embodiment of the present invention in a state where transmission of driving force is released. FIG. 9 is a half cross-sectional view in the state where the driving force is transmitted in the electric assist device of FIG. 8.

As shown in FIGS. 8 and 9, the drive unit (electric assist device) 20A of the first embodiment is different from the drive unit (electric assist device) 20D of the fourth embodiment from the drive shaft 23A. The configuration for transmitting the driving force to the wheels 13 is different.
More specifically, a clutch ring 411 is fitted and fixed to the inner peripheral edge of the tip 29s of the cylindrical portion 29 formed on the wheel 13h. A spline 411 a is formed on the inner peripheral surface of the clutch ring 411.

On the other hand, on the tip side of the drive shaft 23A, a two-sided portion 412 is formed at a position opposed to the cylindrical portion 29 of the wheel 13h in the radial direction, and the clutch plate 413 is pivoted on the two-sided portion 412. It is mounted so that it can reciprocate in the direction and cannot rotate relative to it.
The clutch plate 413 is formed in a substantially disk shape, and a through-hole 413a into which the two-sided portion 412 can be inserted is formed in a substantially radial center. As a result, the clutch plate 413 is attached to the two-way portion 412 so as to be able to reciprocate and not to be relatively rotatable.

A spline 413 b is formed on the outer periphery of the clutch plate 413. The spline 413b can mesh with the spline 411a of the clutch ring 411 that is fitted and fixed to the cylindrical portion 29 of the wheel 13h.
Further, a coil spring 414 is provided on the radially inner side of the cylindrical portion 29 and between the bearing 28 and the clutch plate 413. The coil spring 414 always biases the clutch plate 413 toward the axially outward W.

(Free state)
Under such a configuration, as shown in FIG. 8, in the free state, the lever member 35 does not press the clutch plate 413 by the cam surface 35f. In this state, the clutch spring 414 causes the clutch plate 413 to be positioned at the second position P2 where the engagement with the clutch ring 411 of the cylindrical portion 29 is disengaged.
In this state, the drive shaft 23A of the motor 21 and the wheel 13 are independent of each other. Since the wheel 13 is supported on the drive shaft 23A via the bearing 28, the wheel 13 is rotatable around the drive shaft 23A. That is, the drive shaft 23A functions as a fixed shaft that pivotally supports the wheel 13, and the wheel 13 rotates smoothly when the user manually pushes the electrically assisted silver car 10.

(Assist state)
As shown in FIG. 9, in the assist state, when the lever member 35 is operated to press the sliding contact surface 34f of the sliding contact member 34 against the cam surface 35f, the clutch plate 413 resists the elastic force of the coil spring 414. And is located at the first position P1 where it engages with the clutch ring 411 of the cylindrical portion 29. Then, the clutch plate 413 and the wheel 13h rotate integrally. That is, as a result, the rotational force of the motor 21 is transmitted to the wheels 13 and the traveling of the electrically assisted silver car 10 can be assisted.

(effect)
Therefore, according to the fourth embodiment described above, in addition to the same effects as those of the first embodiment described above, the rotational force of the motor 21 can be transmitted to the wheels 13 more efficiently.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and includes various modifications made to the above-described embodiments without departing from the spirit of the present invention.
For example, the above-described embodiments can be combined or replaced.

  In the first, second, and fourth embodiments, the friction plate 24 is moved by the pressing member 26. However, the present invention is not limited to this. For example, the friction plate 24 may be moved using a cylinder, or the friction plate 24 may be moved by rotating a helical gear, an inclined cam or the like coaxially with respect to the drive shaft. . In addition, the friction plate 24 can be moved by an appropriate mechanism.

  In the first and second embodiments, the friction plate 44 is mounted on the spline shaft portion 23p formed in the small diameter portion 23b, and reciprocates within a range of a certain dimension along the central axis direction of the spline shaft portion 23p. The case has been described in which it is movable and cannot rotate relative to the spline shaft portion 23p. Further, in the fourth embodiment, a two-sided portion 412 is formed in the drive shaft 23A, a through hole 413a is formed in the clutch plate 413 so as to correspond thereto, and the clutch plate 413 is axially disposed with respect to the drive shaft 23A. The case where the reciprocating motion is provided and the relative rotation is impossible is described. However, the present invention is not limited to this, and it is only necessary that the friction plate 44 and the clutch plate 413 are reciprocally movable with respect to the drive shafts 23A and 23B (small diameter portion 23b) and are not relatively rotatable. For example, a D cut may be formed in the small diameter portion 23b, and a hole that can be fitted in the D cut may be formed in the friction plate 44.

  Further, in the first and second embodiments, in order to transmit power from the friction plates 24, 44 to the wheel 13h, tapered surfaces 24t, 44t are formed on the friction plates 24, 44 and tapered surfaces 29t, The case where 41t was formed and the frictional force produced between both was utilized was demonstrated. However, the present invention is not limited to this, and it is only necessary that the power is transmitted from the friction plates 24 and 44 to the wheel 13h by abutting the friction plates 24 and 44 and the wheel 13h. For example, a convex portion may be formed on one of the friction plate 24 and the wheel 13h, and a concave portion into which the convex portion can be inserted may be formed on the other.

  In addition, in the first and second embodiments, the case has been described in which the friction plates 24 and 44 are used to transmit and release the power of the drive shafts 23A and 23B to the wheel 13h. In the third embodiment, the case where the driving power 23A is transmitted to and released from the wheel 13h using the connecting pins 311 and 312 has been described. Further, in the fourth embodiment, the case where the power of the drive shaft 23A is transmitted to and released from the wheel 13h using the clutch ring 411 and the clutch plate 413 has been described. However, the present invention is not limited to these, and various mechanisms can be employed as long as the power of the drive shafts 23A and 23B can be transmitted to and released from the wheel 13h.

In each of the above embodiments, the electrically assisted silver car 10 is taken as an example of the hand-held moving body. However, the present invention is not limited to this, and the present invention is similarly applied to a stroller, a shopping cart, a rehabilitation walking car, a carriage, and the like. Can be applied to.
In addition to this, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate without departing from the gist of the present invention.

10 ... Electric assist silver car (hand-held moving body)
13, 13r ... wheels 20A, 20B, 20C, 20D ... drive unit (electric assist device)
21 ... motor 21s ... support sleeve (cylindrical part)
23A, 23B ... Drive shaft 24 ... Friction plate (transmission member)
24t ... taper surface 25 ... urging member (moving mechanism)
26 ... Pressing member (moving mechanism)
29 ... Cylindrical part (butting part)
29t ... Tapered surface 29v, 344e ... Through hole (power transmission mechanism)
29w, 344d ... Insertion recess (power transmission mechanism)
30 ... Control part 41 ... Cylindrical part (butting part)
41t ... taper surface 44 ... friction plate (transmission member)
44t ... Tapered surface 45 ... Biasing member (moving mechanism)
311, 312 ... connecting pin (power transmission mechanism)
411 ... Clutch ring 413 ... Clutch plate (transmission member)

Claims (7)

A motor that rotates the drive shaft;
A wheel provided on an outer peripheral portion of the drive shaft and provided to be rotatable relative to the drive shaft;
A power transmission mechanism capable of switching between an assist state for transmitting the rotational force of the drive shaft to the wheel and a free state for interrupting transmission of the rotational force of the drive shaft to the wheel;
With
In the free state, the drive shaft causes the drive shaft to function as a fixed shaft for freely rotating the wheel. A motor that rotates the drive shaft;
On the outer peripheral surface of the motor, a wheel rotatably supported by a cylindrical portion formed on the outer peripheral side of the drive shaft;
A power transmission mechanism capable of switching between an assist state for transmitting the rotational force of the drive shaft to the wheel and a free state for interrupting transmission of the rotational force of the drive shaft to the wheel;
With
In the free state, the cylindrical portion functions as a fixed shaft for freely rotating the wheel. The power transmission mechanism is
A transmission member provided so as to be movable along an axial direction of the drive shaft, and provided so as to be movable between a first position in the assist state and a second position in the free state;
The electric assist device according to claim 1, further comprising: a moving mechanism that moves the transmission member between the first position and the second position. An abutting portion that abuts against the transmission member is formed on the wheel,
The transmission member is plate-shaped, and is moved along the axial direction of the drive shaft between the first position that abuts against the abutting portion and the second position that is separated from the abutting portion by the moving mechanism. The electric assist device according to claim 3, wherein the electric assist device moves.   The said abutting part and the said transmission member each have the taper-shaped contact surface from which a diameter reduces gradually toward the said 1st position from the said 2nd position, respectively. Electric assist device.   The electric assist device according to claim 4, wherein an outer peripheral portion of the transmission member hits the abutting portion.   A hand-pushing moving body comprising the electric assist device according to any one of claims 1 to 6.

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