JP2011142972A - Electric wheelchair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce resistance when rotated on an asphalt road surface or the like and to prevent roll-in of an indoor carpet or the like, in a 4-wheel drive wheelchair. <P>SOLUTION: A driving chassis part 20 of the electric wheelchair 1 has right and left front wheels 30f and right and left rear wheels 30r driven by a motor respectively, and casters 50 are arranged behind the rear wheels further. A swing arm 45 is swingably supported by an arm support shaft 28 provided on the rear end wall of a chassis frame 21, and the casters 50 are supported by both right and left ends of the swing arm 45. Then, while the front wheels 30f and the casters 50 contact with the ground on a flat surface, setting is performed so that there is a predetermined gap between the rear wheels 30r and the flat surface. Since the sheelchair is driven on two wheels of the front wheels 30f only on a flat road surface or indoors, smooth rotation is made possible. On a ground road or a gravel road, the casters 50 are sunk in the road surface, the rear wheels 30r contact with the ground, a four-wheel drive state is attained, and high steering stability and the property of covering the whole ground are obtained. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric wheelchair.

Electric wheelchairs are used not only around houses but also as a means of transport for disabled and elderly people, and have expanded to roads in parks, gravel roads, farm roads and coastal sands.
In particular, four-wheel drive electric wheelchairs that use both front and rear wheels as driving wheels can travel stably on hills, pass through uneven steps smoothly, and have excellent straightness. Is desired.
An example of such a four-wheel drive electric wheelchair is disclosed in Japanese Patent Application Laid-Open No. 2004-344289.

JP 2004-344289 A

Here, when there is only one left and right drive wheel, the direction change is performed by a wheel steering type, and even when the left and right wheels are driven in the opposite direction in the case of turning, a circular path centered on the middle point of the left and right wheels. And the rolling direction of the wheel with respect to the running surface (for example, the ground surface) match, and a smooth turning is obtained.
On the other hand, in the four-wheel drive in which the left and right wheels are composed of two front and rear wheels, the direction change is performed in a differential rotation type due to the speed difference between the wheels on both sides. It becomes an intermediate point on the connecting line, and the rolling direction of the wheels does not match the circular track centered on the intermediate point (rotation center). For this reason, especially in the case of fixed-point turning, there is no problem with dirt roads or gravel roads where sand and soil slightly escape, but on a flat asphalt road surface or indoors, the resistance is considerably large, leading to deterioration in power consumption. There is a problem that a carpet or the like is involved when used indoors.

In order to cope with the above-mentioned problem in the four-wheel drive, Japanese Patent Application Laid-Open No. 2004-344289 arranges a plurality of rotors that can rotate in a direction orthogonal to the straight traveling direction of the wheels on the left and right front wheels, While running, the rotation of the rotor is prohibited, while at the time of turning, the rotor is free to rotate to allow a smooth lateral movement component to the front wheels.
However, in such a conventional four-wheel drive wheelchair, a complicated rotor structure must be incorporated in the wheel, and noise is generated due to the operation of the rotor, and above all, an increase in manufacturing cost and a decrease in durability are caused.

  Therefore, in the present invention, firstly, in view of the situation in which the use of electric wheelchairs is expanding while having a simple configuration that does not require a complicated structure on the wheels, the above-mentioned regardless of the indoor or outdoor state or the state of the running surface, An object of the present invention is to provide an electric wheelchair that is highly convenient by suppressing the occurrence of such problems.

  The present invention relates to a four-wheel drive electric wheelchair that uses a pair of left and right front wheels and a rear wheel as drive wheels, respectively, and includes a pair of left and right casters at the rear of the rear wheel, the casters having a swing shaft at the center. The swing arm is supported at both ends of a swing arm that can swing in a plane perpendicular to the longitudinal axis, and a predetermined gap is provided between the rear wheel and the flat surface when the front wheel and the caster are grounded on the flat surface. It was supposed to be.

On a flat road surface or indoors, two-wheel drive is performed using only the front wheels, so that a large resistance is not received during turning, power consumption is reduced, and a carpet or the like is not involved during turning. On the other hand, on castors and gravel roads, casters sink on the road surface and the rear wheels come into contact with each other, resulting in a four-wheel drive state, so that high steering stability and running performance can be obtained.

It is an external appearance side view which shows embodiment of this invention. It is an external appearance rear view which shows embodiment. It is a top view which shows the internal structure of a drive chassis part. It is an AA arrow line view in FIG. It is explanatory drawing which shows operation | movement of a swing caster.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is an external side view of the embodiment, and FIG. 2 is an external rear view.
The electric wheelchair 1 is configured by attaching a chair device 2 on a drive chassis portion 20.
The chair device 2 includes a seat 5 on the main frame 3. The seat 5 includes a seating seat 6 that supports the user's buttocks and thighs, and a backrest portion 7 that supports the user's back. The main frame 3 may be provided with a slide mechanism for moving the seat 5 back and forth, a mechanism for changing the inclination of the seating seat 6, a reclining mechanism for inclining the backrest 7.

A pair of left and right footrest support bars 8 extend downward from the main frame 3, and a foldable footrest 9 that supports a user's foot is attached to the lower end of the footrest support bar 8.
Armrests 10 are provided on the left and right sides of the seating seat 6 via subframes 4 fixed to the main frame 3.
At the front end of the main frame 3, for example, a joystick lever 13 that allows the user to control the traveling direction and the traveling speed of the electric wheelchair is provided in an almost upright state. The joystick lever 13 may be arranged on either the left or right side according to the user.

3 is a plan view showing the internal configuration of the drive chassis 20, and FIG. 4 is a view taken along the line AA in FIG.
The drive chassis unit 20 includes left and right front wheels 30fl and 30fr and left and right rear wheels 30rl and 30rr, and drives these wheels. In the following description, each wheel is generically referred to as “wheel 30”, the front wheel is generically referred to as “front wheel 30f”, and the rear wheel is generically referred to as “rear wheel 30r”. For simplicity, the left front wheel is also called the “left front wheel”, and the right front wheel is also called the “right front wheel”. The same applies to the rear wheels.
Each wheel 30 has, for example, a balloon tire and has a wide shape.

The drive chassis 20 has bearings 32 (32fl, 32fr, 32rl, 32rr) for individually supporting the axles 31 of the wheels 30 on the chassis frame 21.
The chassis frame 21 includes a case-shaped main body 22 having a rectangular planar shape, and a flange 26 extending rearward from the main body 22.
When viewed from the side, the main body 22 has a trapezoidal shape in which an upper portion and a lower portion are chamfered at a front end and a rear end thereof, an upper surface is opened, and the opening is surrounded by a frame member 24. A cover plate that closes the opening may be attached.

The flange portion 26 is coupled to the rear wall 22c of the main body portion 22, and the lower surface 26d thereof is higher than the bottom wall 22d of the main body portion 22 and is parallel to the bottom wall 22d, and the upper surface 26a is coupled to the main body portion 22. The rear end wall 26c of the flange portion 26 has a smaller width in the height direction than the base of the main body portion 22 side.
The lateral width of the flange portion 26 is substantially the same width as the main body portion 22, and the side wall 26 b is on an extension line of the side wall 22 b of the main body portion 22.

The bearing 32 is fixed to the inner surface of the side wall 22 b of the main body 22.
A motor 35 is disposed between the bearing 32fl that supports the axle 31 of the left front wheel 30fl and the bearing 32rl that supports the axle 31 of the left rear wheel 30rl, and is connected to the axle 31 of the left front wheel 30fl by the reduction gear mechanism 33. Yes. The reduction gear mechanism 33 is configured integrally with the bearing 32rl.
An axle 31 from each wheel 30 passes through a bearing 32 and extends toward the center of the main body 22, and a pulley 36 is attached to the end. A belt 37 is stretched between the front and rear pulleys 36 and 36. Thus, a left wheel drive mechanism 40l is formed in which the left front wheel 30fl and the left rear wheel 30rl are rotationally driven by the motor 35 in the same direction.

A motor 35 is similarly arranged between a bearing 32fr that supports the axle 31 of the right front wheel 30fr and a bearing 32rr that supports the axle 31 of the right rear wheel 30rr, and between the pulleys 36 attached to the axle 31 from each wheel 30. A right wheel drive mechanism 40r is formed in which a belt 37 is stretched over and the right front wheel 30fr and the right rear wheel 30rr are driven to rotate in the same direction by the motor 35.
Note that a relief hole 25 for avoiding interference with the motor 35 is provided in the side wall 22b of the main body 22.
At the center in the left-right direction in the main body 22, a battery 42 is disposed between the left wheel drive mechanism 40l and the right wheel drive mechanism 40r. A motor controller (not shown) is also housed in the chassis frame 21 and connected to the joystick lever 13 by wiring.

As shown in FIGS. 2 and 3, the flange portion 26 includes an arm support shaft 28 that extends rearward in parallel with the lower surface 26 d from the center in the left-right direction of the rear end wall 26 c. A swing arm 45 is swingably supported on the arm support shaft 28.
The swing arm 45 has a boss portion 46 provided with a shaft hole 47 that penetrates the arm support shaft 28 in the center in the longitudinal direction (left and right direction), and has shaft holes 49 that are perpendicular to the shaft hole 47 at both ends. A caster support 48 is provided. That is, the shaft hole 49 of the caster support portion 48 is perpendicular to the lower surface 26 d of the flange portion 26.

  Since the arm support shaft 28 is parallel to the lower surface 26d of the collar portion 26 and the lower surface 26d is parallel to the bottom wall 22d of the main body portion 22, the swing arm 45 is perpendicular to the longitudinal axis of the electric wheelchair 1. The arm support shaft 28 swings in the plane with the axis center line of the arm support shaft 28 as the swing axis X. However, it may be swingable in the vertical plane extending in the vertical direction instead of a strict vertical plane.

The caster 50 includes a caster wheel 51, a wheel arm 53 that rotatably supports the caster wheel 51, and a swing shaft 55 that is offset from the rotation axis of the caster wheel 51 and extends from the wheel arm 53. The caster 50 supports the swing shaft 55 in the shaft hole 49 of the swing arm 45, and the caster wheel 51 can swing 360 ° about the shaft hole 49.
The caster wheel 51 is smaller in diameter and smaller than the wheel 30.

The distance L between the shaft holes 49 of the caster support portions 48 at both ends of the swing arm 45 is as far as possible in the range where the caster wheel 51 does not protrude outward from the left and right wheels 30 even when the caster wheel 51 swings to the outermost side in the left-right direction. It is set so that the caster wheel 51 does not interfere with the rear wheel 30r even when the swing arm 45 swings while being close to the row of wheels.
As described above, the drive chassis unit 20 has a configuration of “four-wheel drive + swing caster”.

Further, when the electric wheelchair 1 is stopped on a flat road surface with the swing shaft 55 inserted into the shaft hole 49 and the caster 50 supported by the caster support portion 48, the front wheel 30f and the caster wheel 51 are The layout of the wheels 30 and the casters 50 is set so that a predetermined gap of α = 10 mm is generated between the rear wheel 30r and the road surface, for example, when the user is on the road.
In other words, in a reference state in which the swing arm 45 is in a neutral position, that is, the straight line connecting the caster support portions 48 at both ends is horizontal, the straight line connecting the ground point of the front wheel 30f and the ground point of the caster 50 and the rear wheel 30r A predetermined gap α is provided between them.

In the electric wheelchair 1, the left wheels 30fl and 30rl and the right wheels 30fr and 30rr are rotationally driven in the same direction during forward traveling or backward traveling.
The direction change is performed by a differential rotation method based on the difference in speed between the left and right wheels, and the traveling direction changes to a lower speed side. The fixed-point rotation is performed by driving the left wheels 30fl and 30rl and the right wheels 30fr and 30rr in the opposite directions.
On the flat road surface, the rear wheel 30r is floated by the predetermined distance α and does not come into contact with the road surface, so that the two-wheel drive is performed only by the front wheels 30fl and 30fr. On the ground road or gravel road, the caster wheel has a small diameter and a small width. Since 51 slightly sinks into the road surface, the rear wheels 30rl and 30rr are also grounded to change to the four-wheel drive state.

  Since the caster 50 is supported by the swing arm 45, and the swing arm 45 is supported by the chassis frame 21 at one point of the boss portion, when the two wheels are driven with the rear wheel 30r floating, as shown in FIG. Even when there is a step and the height of the road surface through which the caster 50 passes differs between the left and right, the caster wheels 51, 51 of both the left and right casters follow the change in the road surface due to the swinging of the swing arm 45. . Therefore, by operating this swing caster, it is possible to finely pick up the difference in level between the left and right, and the height of the level difference seen from the chassis frame 21 side is reduced because it is the central support between the left and right casters 50, 50. In addition, the stability is greatly improved and the impact load at the time of passing through a step or the like is reduced.

The embodiment is configured as described above. In the four-wheel drive electric wheelchair using the pair of left and right front wheels 30f and the rear wheel 30r as drive wheels, the pair of left and right casters 50 are provided behind the rear wheel 30r. The left and right casters 50 are supported at both ends of a swing arm 45 that can swing in a vertical plane with the arm support shaft 28 of the chassis frame 21 that supports the shaft hole 47 of the central boss portion 46 as a swing axis. In the state where the front wheel 30f and the caster 50 are grounded on the flat surface, the predetermined gap α is provided between the rear wheel 30r and the flat surface. First, on a flat road surface or an equivalent room, etc. Since it is a two-wheel drive with only the front wheels 30fl and 30fr, it does not receive a large resistance at the time of turning, and the operation is smooth, thus reducing power consumption, and also a carpet at the time of turning. Also eliminated that would involving.
On the other hand, since the caster wheel 51 sinks on the road surface due to the road surface characteristics on a ground road, a gravel road, etc., the rear wheels 30rl and 30rr come into contact with the four-wheel drive state, so that high steering stability and running performance can be obtained.
In order to obtain such an operation, it is not particularly necessary to add a complicated structure to the front wheel 30f or the rear wheel 30r, and this is realized at a low cost.

The left and right wheels are respectively driven by a left wheel drive mechanism 40l and a right wheel drive mechanism 40r that drive one of the front wheel 30f or the rear wheel 30r by the motor 35 and transmit one rotation of the front wheel or the rear wheel to the other. Compared with the case where a motor is provided for each individual wheel, the number of motors is reduced, and the cost can be reduced.
In particular, the left wheel drive mechanism 40l and the right wheel drive mechanism 40r each include a pulley 36 attached to each axle 31 of the front wheel 30f and the rear wheel 30r, and a belt 37 spanned between the pulleys 36, so that the configuration is simple. It can be brought close to the vicinity of the bearing 32 to be compact, and the degree of freedom of battery arrangement for driving the motor is high.

  Further, the swing arm 45 is configured to be supported by the arm support shaft 28 of the flange portion 26 extending rearward from the main body portion 22 that houses the left wheel drive mechanism 40l and the right wheel drive mechanism 40r in the chassis frame 21, and thus the caster 50 is supported. A caster 50 is added to a four-wheel drive electric wheelchair that is not provided by simply attaching a collar portion 26 having an arm support shaft 28 to the rear wall of the chassis frame main body. The configuration of the “caster” can be easily realized.

  The side wall 22b of the main body portion 22 is provided with a clearance hole that avoids interference with the motor 35. Since the motor 35 faces the outside of the main body portion 22 and radiates heat in this clearance hole, heat generation of the motor is also suppressed.

  In the embodiment, the predetermined gap α between the rear wheel 30r and the flat road surface is set to 10 mm. However, the present invention is not limited to this, and the tire 30 may have a tire bending characteristic or a caster wheel gravel road. The value of the predetermined gap α may be set accordingly, and the predetermined gap α may be adjusted and set in accordance with the user's preference and request regarding the switching timing between the two-wheel drive and the four-wheel drive.

Further, the left wheel drive mechanism 40l and the right wheel drive mechanism 40r each drive the front wheel 30f directly by the motor 35 and transmit the rotation to the rear wheel 30r via the pulley and the belt, but the present invention is not limited to this. . For example, the rear wheel 30r can be directly driven by a motor, and the rotation can be transmitted to the front wheel 30f via a pulley, a belt, or other means.
Further, each of the left wheel drive mechanism 40l and the right wheel drive mechanism 40r is preferable in that the front wheel and the rear wheel are driven by one motor 35, and the number of motors is small. However, the present invention is a small and inexpensive wheel-in motor or the like. However, it is not excluded that each wheel is driven by a dedicated motor.

  The swing arm 45 has a shaft hole 47 in its boss portion 46, and the shaft hole 47 is inserted into the arm support shaft 28 of the chassis frame 21 so as to swing. The swing arm may be swingable by supporting the shaft of the swing arm in a shaft hole provided on the chassis frame side.

DESCRIPTION OF SYMBOLS 1 Electric wheelchair 2 Chair apparatus 3 Main frame 4 Sub frame 5 Seat 6 Seating seat 7 Backrest part 8 Footrest support bar 9 Footrest 10 Armrest 13 Joystick lever 20 Drive chassis part 21 Chassis frame 22 Main body part 22b Side wall 22c Rear wall 22d Bottom wall 24d Frame member 25 Escape hole 26 Gutter 26a Upper surface 26b Side wall 26c Rear end wall 26d Lower surface 28 Arm support shaft 30f, 30fl, 30fr Front wheel 30r, 30rl, 30rr Rear wheel 31 Axle 32, 32fl, 32fr, 32rl, 32rr Bearing 33 Reduction gear Mechanism 35 Motor 36 Pulley 37 Belt 40l Left wheel drive mechanism 40r Right wheel drive mechanism 42 Battery 45 Swing arm 46 Boss part 47, 49 Shaft hole 48 Caster support part 50 Caster 51 C Tahoiru 53 Wheel arm 55 swing axis X oscillation axis

Claims (4)

In a four-wheel drive electric wheelchair with a pair of left and right front wheels and rear wheels as drive wheels,
A pair of left and right casters is provided behind the rear wheel,
The casters are supported at both ends of a swing arm having a swing shaft in the center and swingable in a vertical plane,
An electric wheelchair characterized in that a predetermined gap is provided between the rear wheel and the flat surface in a state where the front wheel and the caster are grounded on a flat surface.   The left and right drive wheels are respectively driven by a left wheel drive mechanism and a right wheel drive mechanism that drive one of the front wheels or rear wheels by a motor and transmit the rotation to the other of the front wheels or rear wheels. The electric wheelchair according to claim 1.   The electric wheelchair according to claim 2, wherein each of the left wheel driving mechanism and the right wheel driving mechanism includes a pulley attached to each of the axles of the front wheel and the rear wheel, and a belt stretched between the pulleys.   4. The electric wheelchair according to claim 2, wherein the swing arm is supported by an arm support shaft of a buttock extending rearward from a main body portion housing the left wheel drive mechanism and the right wheel drive mechanism in a chassis frame. .

Images