JP2006116186A - Drive unit for electric vehicle and electric wheelchair having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive unit for an electric vehicle, which is reduced in size, improved in braking performance, and reduced in diameter of drive wheels, and an electric wheelchair having the same. <P>SOLUTION: Each of the drive units provided on the internal circumferences of the left/right driving wheels 80 is provided with a casing 30 cantilevered at the electric vehicle by an axle 22, a motor 40 stored inside the casing 30 and having a rotary shaft 43 coaxial with the axle 22, an electromagnetic brake 60 stored inside the casing 30, disposed closer to the side of the axle 22 than the motor 40 and braking the motor 40, and a housing 50 rotatably fitted around the outer circumference of the casing 30 and rotated by receiving the rotation of the motor 40. The driving wheel 80 is integrally rotatably disposed around the outer circumference of the housing 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a drive device used for an electric vehicle such as an electric wheelchair, and more specifically to an electric vehicle drive device having a drive wheel on the outer periphery and cantilevered with respect to the vehicle. is there.

Some electric vehicles such as an electric wheelchair include a driving device that individually drives left and right driving wheels by a motor. For example, in the drive device described in Patent Document 1, an opening of a hollow hub case rotatably attached to an axle is covered with a metal lid at the center of a drive wheel, and the opposite side of the lid from the hub case A case containing a drive wheel motor and an electromagnetic brake is fixed at a position offset with respect to the axle on the surface, and a reduction gear and a power control unit are housed in the hub case.
The lid is made of a metal having high thermal conductivity, and enhances the heat dissipation effect of the motor and the power control unit. Moreover, it has the structure which suppresses the overheating of a power control part by providing the attachment position of a power control part in the position away from the motor with respect to the axle.

Japanese Patent No. 3432977

In the above drive device, the motor and the electromagnetic brake are provided on the opposite side of the hub case with the cooling lid interposed therebetween, and are located offset from the axle, so the diameter of the drive device is large. Inevitably (about 30 to 40 cm), the wheel diameter provided on the outer periphery of the drive unit also becomes large.
When the wheel diameter increases, it may become difficult to move from the wheelchair to the bed, etc.When the wheel diameter increases, the wheelchair itself becomes larger and heavier. There was inconvenience.

  An object of the present invention is to provide a drive device for an electric vehicle capable of achieving a reduction in the size of the device and a reduction in the diameter of a drive wheel, and an improvement in braking performance, and an electric wheelchair provided with the drive device.

In order to solve the above-described problems, an electric vehicle drive device of the present invention includes:
In the drive device provided on the inner periphery of the left and right drive wheels of the electric vehicle,
A casing that is cantilevered by an electric vehicle by an axle;
A motor housed in the casing and having a rotational axis coaxial with the axle;
An electromagnetic brake housed in the casing and disposed on the axle side of the motor to brake the motor;
A housing that fits freely on the outer periphery of the casing and rotates in response to the rotation of the motor,
A drive wheel is arranged on the outer periphery of the housing so as to be integrally rotatable.

In the drive device of the present invention, since the axle supporting the drive device and the rotation shaft of the motor are provided coaxially, the drive device itself can be reduced in size and the diameter of the drive wheel attached to the outer periphery of the drive device can be reduced. be able to. In addition, since the rotation shaft and the rotation center of the drive wheel are the same, the reaction force can be prevented from being biased, and the reaction force can be received by the coaxial axle without bias.
By providing the electromagnetic brake on the axle side of the motor, the wiring of the electromagnetic brake can be shortened, the internal structure can be simplified, and the maintenance can be improved.

In the following description, an electric wheelchair (10) used by an elderly person or a handicapped person such as a foot will be described as an example of an electric vehicle.However, the present invention is not limited to a golf cart or a small vehicle. This can also be applied to electric vehicles.
FIG. 1 is a perspective view of an electric wheelchair (10) in which the drive device (20) of the present invention is disposed on left and right drive wheels (80) and (80), respectively. The electric wheelchair (10) includes a seat (11) and a backrest (12) on which a user sits, and a frame (13) extending downward from the seat (11) has a pair of left and right drive devices (20) ( 20) and driving wheels (80) and (80) are attached. Further, auxiliary wheels (14) (14) having a smaller diameter than the drive wheels (80) (80) are supported in front of the drive wheels (80) (80).
A control box (15) such as a battery, a power control unit and other control means is arranged at the lower part of the seat part (11), and a footrest pedal (16) (16 ) And elbow rests (17) and (17) are formed on the left and right sides of the seat (11). Furthermore, the operating device (18) operated by the user is provided on the side of one of the elbow rests (17), and the handle (19) (19) (19 ) Is extended.

  As the operating device (18), a joystick type can be exemplified, and a vehicle speed can be changed and a turning operation can be performed. The electric wheelchair (10) can be moved forward and backward by tilting the joystick forward or backward. Further, by tilting the joystick left and right, the electric wheelchair (10) can be turned left and right by changing the rotational speed of the left and right drive wheels (80) and (80).

  FIG. 2 is a cross-sectional view of the drive device (20) of the present invention and the left drive wheel (80) attached to the drive device (20). 3 is a side view of the drive device 20 as viewed from the direction of arrow A in FIG. 2, and FIG. 4 is a side view of the drive device 20 as viewed from the opposite direction.

The drive device (20) is provided in a casing (30) in which an axle (22) attached to the frame (13) of the electric wheelchair (10) projects toward the frame (13) side, and the casing (30). The motor (40), the rotation shaft (43) of the motor (40) and the reduction gear (48), and the housing (50) and the casing (30) that are rotatable with respect to the casing (30). And an electromagnetic brake (60) that links the rotating shaft (43) of the motor (40) in a brakeable manner. A drive wheel (80) is fitted on the outer periphery of the drive device (20).
The casing (30) and the housing (50) are preferably formed of a metal material having high thermal conductivity, for example, an aluminum alloy, in order to improve heat dissipation characteristics.

The casing (30) that is cantilevered by the frame (13) via the axle (22) can be divided into three in the axial direction. The inner casing (31) located on the frame (13) side is closed by an end plate (32) to which the tip of the axle (22) is fixed, and the other end is open. The axle (22) can be attached by press-fitting into the inner casing (31).
One end of the middle casing (35) is fixed to the inner casing (31). The inner peripheral surface includes an annular plate (36) extending toward the rotating shaft (43) of the motor (40), and a bearing (rotatingly supporting the rotating shaft (43) on the inner peripheral edge of the annular plate (36) ( 36a). An electromagnetic brake (60) is attached to the annular plate (36) on the inner casing (31) side, and a stator (46) of the motor (40) is fixed to the rear surface.
One end of the outer casing (37) is fixed to the middle casing (35) and surrounds the outer periphery of the stator (46). An annular end plate (38) is provided at the other end of the outer casing (37), and a bearing (37) that rotatably supports the rotating shaft (43) of the motor (40) is provided on the inner peripheral edge of the end plate (38). 38a) is arranged. A reduction gear (48) is attached to the outer surface of the end plate (38).

The wiring (24) for energizing the stator (46) and the electromagnetic brake (60) penetrates (32a) the end plate (32) of the inner casing (31), and the control box ( 15).
As shown in FIG. 2, the end plate (32) of the inner casing (31) is formed with a plurality of radiating fins (34) in addition to the through hole (32a) through which the wiring (24) passes. The radiating fin (34) is air-cooled by rotation of a blade (52) provided in a housing (50) described later.

The rotor (42) of the motor (40) rotates so as to face the stator (46) and the rotating shaft (43) supported by the bearings (36a) (38a) so as to be coaxial with the axle (22). It is composed of a laminated metal plate (44) fitted to the shaft (43).
The frame side of the rotating shaft (43) passes through the inside of the electromagnetic brake (60), and a key groove (43a) that engages with the inner driver (62) of the electromagnetic brake (60) is cut. The inner driver (62) is engaged with the brake disc (61).
The other end of the rotating shaft (43) meshes with the reduction gear (48).

As the electromagnetic brake (60), a known non-excited operation brake can be used. When the electromagnetic brake (60) is energized, the coil (63) is energized to release the brake, and when not energized, the brake disc (61) is crimped by the spring force to directly brake the rotating shaft (43). be able to. Thereby, braking performance can be improved.
The electromagnetic brake (60) is provided closer to the axle (22) than the motor (40). By providing the electromagnetic brake (60) on the axle (22) side in this way, the wiring (24) of the electromagnetic brake (60) can be shortened, the internal structure can be simplified, and maintainability can be improved. Can be achieved.
If the electromagnetic brake (60) is placed outside the reduction gear (48), the wiring (24) of the electromagnetic brake (60) must be routed outside the reduction gear (48) and motor (40). The internal structure becomes complicated, leading to an increase in the size of the device and a decrease in maintainability.

The reduction gear (48) can be exemplified by a planetary gear mechanism. The reduction gear (48) is supported between an end plate (38) of the outer casing (37) and a holding plate (39) fixed facing the end plate (38). The reduction gear (48) meshes with an internal gear (55) cut inside the lid (54) that closes the tip of the housing (50).
When the rotor (42) rotates by energizing the stator (46), the driving force is transmitted to the lid (54) via the reduction gear (48) and the internal gear (55), and the housing (50) rotates. To do.

The frame side of the housing (50) is supported by the inner casing (31) via a bearing (30a), and the opening at the other end is closed by a lid (54).
The lid (54) has the internal gear (55) cut off as described above, and can freely rotate through the bearing (39a) on the shaft (39b) protruding from the center of the holding plate (39). It is supported.
On the frame side of the housing (50), a plurality of blades (52) (52) are projected toward the axle (22). The blades (52) and (52) are opposed to the heat dissipating fins (34) and (34) of the inner casing (31), and the rotation of the housing (50) causes the blades (52 and 52) to dissipate the heat dissipating fins (34). Air is sent to (34) to act as a cooling fan. Thereby, the heat generated from the motor (40), the electromagnetic brake (60), etc. is efficiently dissipated without staying inside.

The drive wheel (80) includes a cylindrical hub case (82) that fits and rotates integrally with the outer periphery of the housing (50) of the drive device (20), and a plurality of spokes (83) provided on the outer periphery of the hub case (82). ), An annular rim (84) linking the tips of the spokes (83), and a rubber tire (85) fitted to the rim (84).
The drive wheel (80) is preferably formed at a position where the drive device (20) does not protrude from the tire (85). In the case of this embodiment, by providing the spoke (83) at the tip side of the hub case (82), that is, the position opposite to the axle (22), the protrusion amount of the drive device (20) from the tire (85) Is made smaller.

The drive device (20) configured as described above is fixed to the electric wheelchair (10) in a state where the axle (22) is cantilevered to the frame (13). When the drive device (20) is used without being detached from the electric wheelchair (10), the drive device (20) may be fixed to the frame (13) by bolting or the like. When it is necessary to remove the drive wheel (80) together with the drive unit (20) for reasons such as loading in a car, the purpose is to prevent axial removal so that the drive unit (20) can be easily removed. It is good also as a structure. A member that receives the torque reaction force of the motor (40) may be provided as necessary.
When the user instructs the electric wheelchair (10) to move forward, backward, or turn via the actuator (18), the electromagnetic brake (60) is energized, the brake is released, and the stator (46) is energized. And the rotor (42) rotates. When the rotor (42) rotates, the driving force is transmitted from the rotating shaft (43) to the housing (50) via the reduction gear (48) and the internal gear (55), and the housing (50) rotates. As a result, the drive wheels (80) (80) fixed to the housing (50) rotate, and the electric wheelchair (10) moves forward and backward. Further, the turning is performed by changing the rotational speeds of the left and right drive devices (20).

According to the drive device (20) of the present invention, since the electromagnetic brake (60) is provided on the axle (22) side as described above, the wiring (24) of the electromagnetic brake (60) can be shortened. There is an advantage that the internal structure can be simplified and improvement in maintainability can be achieved.
Moreover, since the electromagnetic brake (60) directly brakes the rotating shaft (43) of the motor (40), the braking performance can be improved.

  Further, the drive device (20) of the present invention is provided with the axle (22) supporting the drive device (20) and the rotation shaft (43) of the motor (40) coaxially, so that the drive device (20) itself Miniaturization (diameter of about 15 cm or less) can be achieved, and the diameter of the drive wheel (80) attached to the outer periphery of the drive device (20) can be reduced. Further, since the rotation centers of the rotating shaft (43) and the drive wheel (80) are the same, the reaction force can be prevented from being biased, and the reaction force can be received by the coaxial axle (22) without bias.

Further, according to the drive device (20) of the present invention, the casing (30) is provided with the radiation fins (34), and the blades (52) and (52) for cooling the radiation fins (34) are provided on the housing (50). In addition, since the casing (30) and the housing (50) are made of a material having high thermal conductivity, heat generated by driving the motor (40) or the like does not accumulate inside the driving device (20), and it is efficient. Can dissipate heat.
In the above embodiment, the radiating fin (34) is formed integrally with the housing (50), but it may be formed by a separate member, or provided in the hub case (82) of the drive wheel (80). May be.

  INDUSTRIAL APPLICABILITY The present invention is useful as a drive device for an electric vehicle that can achieve downsizing of the device and can reduce the diameter of drive wheels.

It is a perspective view of an electric wheelchair. It is sectional drawing of the drive device and drive wheel of this invention. It is the side view which looked at FIG. 2 from the arrow A direction. It is the side view which looked at FIG. 2 from the direction opposite to the arrow A.

Explanation of symbols

(10) Electric wheelchair
(20) Drive unit
(22) Axle
(30) Casing
(34) Radiation fin
(40) Motor
(43) Rotating shaft
(50) Housing
(60) Electromagnetic brake
(80) Drive wheel

Claims (3)

In the drive device provided on the inner periphery of the left and right drive wheels (80) (80) of the electric vehicle,
A casing (30) that is cantilevered to the electric vehicle by an axle (22);
A motor (40) housed inside the casing (30) and having a rotating shaft (43) coaxial with the axle (22);
An electromagnetic brake (60) housed in the casing (30) and disposed on the axle (22) side of the motor (40) to brake the motor (40);
A housing (50) that fits freely on the outer periphery of the casing (30) and rotates by receiving the rotation of the motor (40),
A drive device characterized in that a drive wheel (80) is disposed on an outer periphery of a housing (50) so as to be integrally rotatable.   The drive device according to claim 1, wherein the electromagnetic brake (60) directly brakes the rotating shaft (43) of the motor (40).   An electric wheelchair comprising the electric vehicle drive device (20) according to claim 1 or 2 on the left and right.

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