JP2000070310A - Front-drive and rear-steering type electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the stability in straight and turning traveling. SOLUTION: For example, in the right turn, rear wheels 6a, 6b are surely steered by a specified quantity in the left direction (the direction of the arrow) through a steering mechanism 9 based on the rotation quantity and the rotational direction of a steering motor 8 according to the operation quantity of a controller. That is, the rotation quantity and the rotational direction of the motor 8 are converted into the rotation quantity and the rotational direction of an output shaft 10a of worm gear sets, and when a first bracket 11 directly connected to the output shaft 10a is rotated by a specified quantity in the direction of the arrow in the figure, the rear wheel 6a is steered by a specified quantity in the same direction as a second bracket 16a fixed to an axle arm through a steering link 13a is rotated in the direction of the arrow. The rear wheel 6b is steered by a specified quantity in the same direction as a second bracket 16b fixed to an axle arm through a steering link 13b is rotated in the direction of the arrow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric walking vehicle suitable for the elderly and handicapped, and more particularly to a front-wheel-drive and rear-wheel-steering electric walking vehicle with improved stability during running.

[0002]

2. Description of the Related Art As an electric walking vehicle suitable for elderly people or people with disabilities who have weak legs or a handicap, Japanese Patent Application Laid-Open No. H10-10810 discloses an electric walking vehicle having a wheelchair or a standing posture. No. 57425. Of these, those that can be driven in a standing position
Recently, attention has been paid to the advantage of activating the elderly and the disabled. As shown in FIGS. 3 and 4, in such an electric traveling vehicle 100, a pair of batteries 102a and 102b are mounted on a front frame 101, and these batteries 1
02a, 102b drive the electric motors 105a, 105b via the controller 103 to drive the front wheels 104a, 104b.
05b, respectively, the occupants 1 such as the elderly and the disabled
06 operates the controller 103 to control the rotation speed and rotation direction of the electric motors 105a and 105b, and as shown in detail in FIG. Short pipes 108a and 108b are fixed to the ends, respectively. A rear wheel 110a is attached to a steering fork 109a fixed to the short pipes 108a and 108b, and a rear wheel 110b is attached to the steering fork 109b to form a so-called caster. ing.

[0003]

However, as a motorized walking vehicle suitable for the elderly and the handicapped, a conventional structure in which the front wheels are driven as shown in FIGS. 3 and 4 and the rear wheels form casters, or Although the explanation is omitted, the conventional structure that drives the rear wheel and the front wheel forms a caster has a problem in stability when running, especially when running on a road with a slope or a step. This makes it difficult for the occupant operating the walking vehicle to travel as intended. Furthermore, even in the case of turning, the structure of the conventional caster has a lack of stability, and the use of the electric walking vehicle is elderly or disabled. Was extremely important.

An object of the present invention is to provide a front-wheel-drive and rear-wheel-steering electric walking vehicle capable of ensuring stability during straight-ahead running and cornering.

[0005]

In order to solve the above problems, a front-wheel drive / rear-wheel steering electric walking vehicle according to the present invention is provided.
Elderly or handicapped, etc., is an electric walking vehicle having four wheels suitable for driving in a sitting posture or in a standing posture, and a front wheel, for example, a primary battery, a secondary battery, a chemical battery such as a fuel cell, or A first electric motor is driven by a power source supplied from a physical battery such as a solar cell (hereinafter, simply referred to as a battery), and a rear wheel is driven by a battery for the first electric motor, or The second electric motor is driven by another vehicle-mounted battery as a power source to enable steering, whereby the rear wheels are forcibly steered as intended by the occupant.・
Stability during cornering is ensured. By the way, the first
The electric motor drives each of the left and right front wheels,
It is preferable to use one for the left front wheel and one for the right front wheel.

A steering mechanism for a front-wheel drive / rear-wheel steering electric walking vehicle according to the present invention, which is particularly simple and engages with an output shaft of a second electric motor disposed parallel to the rear wheel axle. A first bracket directly connected to an output shaft of a reduction gear, for example, a worm gear pair or a bevel gear pair, which converts the rotation of the output shaft into rotation about an axis perpendicular to the output shaft; A pair of steering links rotatably mounted by a joint disposed forward of the output shaft of the reduction unit, and one end of one of the steering links rotatably mounted at one end by, for example, a joint; Is attached to one end of the rear wheel axle arm, and the other of the steering links is rotatably attached to one end by, for example, a joint, and the other end is fixed to the other of the rear wheel axle arm. When the vehicle travels straight as intended by the occupant, that is, for example, on a slope or a stepped road surface, the second electric motor forcibly applies the rear wheel axle arm. When the rear wheel that is mounted on the shaft is maintained in the straight running direction, while turning left and right,
Since the second electric motor operates to reliably steer the rear wheel to the left or right, stable turning can be performed. By the way, the form of the steering mechanism is different from that of the above-described steering mechanism, and the joint provided on the first bracket may be provided at a position rearward of the output shaft of the speed reduction unit. Of course. The “front” at the front position is
The term “rear” at the rear position refers to the retreating direction of the electric walking vehicle. The joint provided on the first bracket or the joint between the steering link and the second and third brackets is generally considered to be a ball joint, but is not limited thereto. Joint).

[0007]

FIG. 1 shows an example of an embodiment of the present invention.
This will be described with reference to FIGS. As shown in FIG. 1, a battery 3 is mounted on a front-wheel drive / rear-wheel steering electric walking vehicle 1 according to the present embodiment at a position between the left and right front wheels 2 a and 2 b above a front portion of a vehicle body. A drive motor (first electric motor) corresponding to the front wheels 2a, 2b
4a, 4b are connected, and the drive motors 4a, 4b
4b are attached to the axles of the front wheels 2a, 2b via reduction gears 5a, 5b, respectively, and the occupants such as the elderly and the handicapped operate the controllers (not shown) to rotate the drive motors 4a, 4b. The speed and the rotation direction can be controlled, whereby the electric walking vehicle 1 can be moved forward and backward, and the speed can be adjusted.

As shown in FIGS. 1 and 2, the electric walking vehicle 1 has a rear lower part of the vehicle body and right and left rear wheels 6.
a, 6b and the rear wheels 6a, 6b
The steering motors (second
An electric motor (motor) 8 is mounted, and the rear wheels 6a and 6b can be steered right and left by a steering motor 8 via a steering mechanism 9. The steering mechanism 9 is engaged with an output shaft of a steering motor 8 connected to the battery 3 and converts a rotation of the output shaft into a rotation about an axis perpendicular to the output shaft (a reduction gear unit). 10
A first bracket 11 directly connected to the output shaft 10a of the worm gear pair 10 and a ball joint (joint) 12 disposed at a position forward of the output shaft 10a of the worm gear pair 10 on the first bracket 11 so as to be rotatable. The steering links 13a, 13b provided, a steering link 13a is rotatably attached to one end by a ball joint (joint) 14, the other end is fixed to an axle arm 15a of the rear wheel 6a, and one end is provided. And a third bracket 16b fixed to the axle arm 15b of the rear wheel 6b at the other end while the steering link 13b is rotatably mounted by a ball joint (joint) 14. The operation controls the amount and direction of rotation of the steering motor 8. , The rear wheels 6a, 6b are steered.

The electric walking vehicle 1 is an electric vehicle having a structure in which occupants of the elderly and the disabled can operate in a standing posture, and the vehicle body structure itself is substantially the same as the vehicle body structure of FIG. Therefore, the vehicle body structure for the electric walking vehicle 1 is not shown, but the structure is outlined with reference to FIG. 3. The side cross section of the vehicle body has a substantially U-shaped frame shape, and The floor panel is fixed to the occupant so that the occupant can ride in the standing posture, and the battery 3 and the front wheels 2a and 2b are disposed on the front frame side, and a grip portion is provided at an upper end of the front frame. The rear wheels 6a and 6b are disposed on the rear frame side, and the upper end of the rear frame has a buttocks and waist receiving portions for supporting the buttocks and hips of the occupant. Is attached so that the elderly and the disabled can use it instead of walking.

Next, the operation of the electric walking vehicle 1 when traveling straight and turning will be described with reference to the drawings. In the case of straight running, the rear wheel 6 is forcibly driven by the steering motor 8.
Since a and 6b are maintained in the straight traveling direction, the occupant can operate the controller to control the rotation speed and the rotation direction of the drive motors 4a and 4b, and can travel straight or backward at the desired speed. In the case of turning, a controller operation for controlling the rotation speed and rotation direction of the steering motor 8 is required. For example, in the case of turning right, when the controller is instructed to turn right by operating the controller, the rear wheel 6a is turned through the steering mechanism 9 based on the rotation amount and the rotation direction of the steering motor 8 according to the operation amount. , 6b are securely steered by a predetermined amount to the left (in the direction of the arrow in FIG. 1). That is, the rotation amount and the rotation direction of the steering motor 8 are controlled by the output shaft 10 of the worm gear pair 10.
When the first bracket 11 directly connected to the output shaft 10a is rotated by a predetermined amount in the direction of the arrow in FIG. 3, the rear wheel 6a is fixed to the axle arm 15a via the steering link 13a. Second bracket 1
The steering wheel 6a is steered by a predetermined amount in the same direction as it rotates in the direction of the arrow in FIG.
As the second bracket 16b fixed to the axle arm 15b via the 3b rotates in the direction of the arrow in FIG.

In this case, the steering amount of the rear wheels 6a and 6b, that is, the steering angle of the rear wheel 6b is larger than that of the rear wheel 6a, but the turning radius corresponding to the steering amount of the rear wheel 6b is: The center of turning of both is smaller than that of the rear wheel 6a, and
A and 2b are set so as to coincide on the extension line of the axle, and both draw concentric circles. Thus, the right and left rear wheels 6a and 6b can be turned smoothly without slipping around the turning center (Ackerman's principle).

By the way, in the electric walking vehicle 1, when turning right as described above, control is performed such that a difference occurs in the rotation speed of the front wheels 2a, 2b with the steering of the rear wheels 6a, 6b. That is, by detecting the amount of steering, the rotational speed of the front wheel 2a is increased and the front wheel 2b
If control is performed to reduce the rotation speed of
Since a sharp right turn can be performed, it is preferable to improve the function.

[0013]

According to the electric walking vehicle with front-wheel drive and rear-wheel steering according to the present invention, it is possible to ensure stability during straight running and turning traveling.

[Brief description of the drawings]

FIG. 1 is a plan view of a suspension portion of an electric walking vehicle according to an embodiment.

FIG. 2 is a view as viewed in the direction of the arrow A in FIG.

FIG. 3 is a side sectional view of a conventional electric walking vehicle.

FIG. 4 is a perspective view of a rear portion of the electric walking vehicle shown in FIG. 3;

[Description of Signs] 1 Electric walking vehicle 4a, 4b Drive motor (first electric motor) 6a, 6b Rear wheel 7a, 7b Axle 8 Steering motor (second electric motor) 9 Steering mechanism 10 Worm gear pair (reduction unit) 10a Output shaft 11 First bracket 12, 14 Ball joint (joint) 13a, 13b Steering link 15a, 15b Axle arm 16a Second bracket 16b Third bracket

Claims (2)

[Claims] 1. An electric walking vehicle having four wheels suitable for the elderly and handicapped, wherein a front wheel is driven by a first electric motor and a rear wheel is steered by a second electric motor. An electric walking vehicle with drive and rear wheel steering. 2. A steering mechanism operated by the second electric motor engages with an output shaft of the second electric motor disposed in parallel with the rear wheel axle, and controls rotation of the output shaft. A first bracket directly connected to the output shaft of the reduction unit for converting rotation around an axis perpendicular to the shaft, and a joint of the first bracket disposed at a position forward of the output shaft of the reduction unit. A pair of steering links respectively attached to one end, a second bracket having one end rotatably attached to one end of the steering link and the other end fixed to one of the axle arms of the rear wheel, and The front wheel drive / rear according to claim 1, further comprising a third bracket fixedly attached to the other of the steering links and the other end fixed to the other of the axle arms of the rear wheels. Wheel steering electric walking Train.