JPH09192174A - Power steering device for motor-driven wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the waterproof property of an electronic substrate and a steering angle sensor and the radio wave resistance of the electronic substrate, to facilitate the attachment and detachment of the entire power steering device and to improve maintainability. SOLUTION: In this power steering device 11 for a motor-driven wheelchair, a metallic box-type circuit case 20 opened upwards is installed on a steering mechanism part 40, the electronic substrates 67 and 68 and the steering angle sensor 60 are arranged inside the circuit case 20, the turning shaft (sector shaft 44) of the steering mechanism part 40 is introduced inside the circuit case 20 from a lower part and a steering angle transmission means (sensor drive gear 45 and sensor driven gear 65) for transmitting the turning amount of the turning shaft to the steering angle sensor is put inside the circuit case 20. Also, the circuit case 20 and a motor plate 21 for supporting a motor unit 50 are lined up in a car width direction and connected and connection parts 25 and 30 to a car body frame 2 are formed on the outer end part of the circuit case 20 and the outer end part of the motor plate 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering device for an electric wheelchair.

[0002]

2. Description of the Related Art Some electric wheelchairs that are driven by the power of an electric motor have a power steering device. This power steering device is configured to steer the steered wheels (generally the front wheels) by the power of a motor unit that is different from the electric motor for traveling. The steering mechanism section for steering the wheels, an electronic board for controlling the operation of the motor unit, and a steering angle sensor for detecting the steering angle of the steered wheels and inputting the steering angle to the electronic board are provided. All of these devices are collectively installed in the vicinity of the steered wheels, that is, in the lower front of the seat, and the respective constituent parts are individually fixed to the vehicle body frame.

[0003]

However, since the front lower part of the seat is close to the road surface and is easily exposed to wind and rain, when the power steering device is installed at this position, especially the electronic board and the steering angle sensor are waterproof. It is necessary to secure At the same time, it is necessary to secure the resistance to radio interference of the electronic board.

Further, since a plurality of devices constituting the power steering device are individually fixed to the vehicle body frame in the lower front part of the seat, it is difficult to attach / detach the power steering device as a whole, and maintainability is very high. In addition, when mounting the power steering device on an electric wheelchair that does not have a power steering device, a large number of mounting brackets and the like must be newly installed on the vehicle body frame by welding, etc., and extensive modification is required. It was

Further, there is a portion where the components of the power steering device project from the outer peripheral contour of the vehicle body frame, and there is a high possibility that this portion collides with an external object and is damaged. If the entire power steering device is arranged inside the outer peripheral contour of the vehicle body frame, it will be difficult to attach and detach each part and the maintainability will be significantly deteriorated.

The present invention has been made to solve these problems, and a first object of the present invention is to improve the waterproofness of an electronic board and a steering angle sensor, and the electromagnetic wave resistance of the electronic board. An object of the present invention is to provide a power steering device for an electric wheelchair that can be used.

A second object of the present invention is to improve the maintainability by facilitating the attachment and detachment of the entire power steering device, and to improve the maintainability of an electric wheelchair without a power steering device without the need for major remodeling. It is to be able to install the device.

Further, a third object of the present invention is to prevent the devices constituting the power steering device from colliding with an external object and being damaged without impairing maintainability.

[0009]

In order to achieve the above object, a power steering device for an electric wheelchair according to the present invention has a steering mechanism section for steering steered wheels and a steering mechanism for steering the steering wheel. A power steering device for an electric wheelchair including a motor unit serving as a power source of a mechanism unit, an electronic board that controls the operation of the motor unit, and a steering angle sensor that detects a steering angle of a steered wheel and inputs the steering angle to the electronic board. A box-shaped circuit case made of metal and opening upward is installed above the steering mechanism section, and the electronic board and steering angle sensor are placed in this circuit case, and the rotation axis of the steering mechanism section is adjusted from below to the circuit. A steering angle transmitting means for introducing the rotation amount of the rotation shaft to the steering angle sensor is provided in the case and is provided in the circuit case.

Further, as described in claim 2, the circuit case and the motor plate for supporting the motor unit are connected side by side in the vehicle width direction, and the vehicle body is connected to the outer end portion of the circuit case and the outer end portion of the motor plate. A connection to the frame was provided.

Further, as described in claim 3, the body frame is constructed in a horizontally lying ladder type, and the circuit case and the motor plate are arranged between the overhang portions of the left and right vertical frame members.

Further, as described in claim 4, a box-shaped cover member having a downward opening is covered from above the circuit case and the motor plate, and the lower surface of the top plate of the cover member is closely attached to the circuit case. The frame part which fits in was provided.

Further, as described in claim 5, the cover member is made of a non-metallic material, and the inner area of the frame portion is covered with the metal plate.

[0014]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an electric wheelchair to which the power steering device according to the present invention is applied, as seen from the front right diagonal direction.

The electric wheelchair 1 is provided with a body frame 2 made of, for example, a pipe, a seat 3 is installed on the upper part of the body frame 2, and armrests 4 are provided on the left and right of the seat 3. There is. A rear wheel 5 as a driving wheel is pivotally supported on the lower rear portion of the vehicle body frame 2, and a front wheel 6 as a steered wheel is provided on the lower front portion of the vehicle body frame 2. A foot rest 7 is provided in front of the front wheel 6.

Below the seat 3 is mounted a power unit 8 in which an electric motor for traveling and a battery for power supply are integrally formed, and the rear wheel 5 is driven by this power unit 8. It is like this.

On the other hand, the front wheel 6 is supported by casters 9 and is rotatable left and right. The power steering device 11 according to the present invention is installed above the front wheel 6, that is, in front of the lower portion of the seat 3. ing. The power steering device 11 is for steering operation of the front wheels 6.

Further, for example, a control box is provided on the right armrest portion 4.
The control box 12 is provided with a traveling speed adjusting switch 13, a forward / reverse switching switch 14, etc. on the upper surface of the control box 12, and a steering lever 15 for setting the traveling direction is provided on the front surface of the control box 12. Is provided. When the steering lever 15 is rotated to the left or right, the power steering device 11 steers the front wheel 6 according to the rotation direction and the rotation amount, and the traveling direction of the electric wheelchair 1 is determined.

FIG. 2 is a plan view showing the front portion of the vehicle body frame 2, the front wheels 6, and the power steering device 11. As shown in this figure, the vehicle body frame 2 is constructed in a ladder shape that lies horizontally by connecting a pair of left and right vertical frame members 17L, 17R with several horizontal frame members 18 extending in the vehicle width direction. A shaft portion 19 of a caster 9 that supports the front wheel 6 is pivotally supported at the tip ends of the vertical frame members 17L and 17R.

Then, as also shown in FIGS. 3 and 4,
The power steering device 11 is configured to include a box-shaped circuit case 20 that is made of metal and that opens upward, and a motor plate 21 that is made of sheet metal press. The circuit case 20 and the motor plate 21 are arranged side by side in the vehicle width direction and connected to each other. The overhang portions of the left and right vertical frame members 17L and 17R, that is, the left and right vertical frame members 17L and 17R.
Are arranged between the portions that extend forward of the lateral frame member 18 that is located furthest forward. The circuit case 20 is arranged on the right side in the traveling direction, and the motor plate 21 is arranged on the left side in the traveling direction.

The circuit case 20 is made of, for example, aluminum die-cast, and has a substantially rectangular plan shape as shown in FIG. 5, and a bay insertion portion 23 is formed at an end portion on the left side in the traveling direction, and a cylinder is provided in front of the insertion portion 23. -Shaped bosses 24 are integrally formed so as to penetrate the floor plate. A pair of front and rear connecting portions 25 are formed at the right end of the circuit case 20 in the traveling direction, and the connecting portions 25 are fastened and fixed to the right vertical frame member 17R by bolts 26. Further, a fixed bracket 27 and a fixed bracket 28 are provided at the rear edge and the left end of the circuit case 20, respectively.
And is fixed to the horizontal frame member 18.

On the other hand, as shown in FIGS. 4 and 6, the motor plate 21 has a pair of front and rear connecting portions 30 formed at an end portion on the left side in the traveling direction thereof. It is fastened and fixed to the vertical frame member 17L. Further, the motor plate 21 is formed with two fastening pieces 32 and 33, and the fastening piece 32 is fixed to the circuit case 20 with the bolt 34.
The fastening piece 33 is fastened to the fixed bracket 28 and the fastening piece 33 is fastened to the bottom surface of the circuit case 20 with a bolt 35. Therefore,
The motor plate 21 is overlapped and connected under the circuit case 20.

Further, a cylindrical sleeve 36 extending upward is fixed to the motor plate 21 by press fitting or the like.
The sleeve 36 is densely inserted into the boss 24 of the circuit case 20 from below when the motor plate 21 is connected to the circuit case 20. A gear hole 37 and three motor unit mounting holes 38 surrounding the gear hole 37 are formed near the sleeve 36.

Below the circuit case 20 and the motor plate 21, there is provided a steering mechanism section 40 for steering the front wheels 6 which are steered wheels (see FIG. 2). The steering mechanism section 40 is configured as follows, for example.

First, a sector gear arm 41, which is the center of the steering mechanism 40, is pivotally supported by the sleeve 36 fixed to the motor plate 21. This sector gear arm 41
As shown in FIG. 7 and FIG.
42 and a substantially T-shaped sector arm fixed to its lower surface
43 and a sector shaft 44 that is fixed through the center of the sector gear 42.

The sector shaft 44, which serves as the rotation axis of the steering mechanism section 40, is inserted into the sleeve 36 of the motor plate 21 from below, and can rotate smoothly without any play. Therefore, the entire sector gear arm 41 can freely rotate about the sector shaft 44. A sensor drive gear 45, which also serves as a retainer for the sector gear arm 41, is provided integrally with the upper end portion of the sector shaft 44 so as to rotate together, and the rotation angle of the sector gear arm 41 is restricted on the lower surface of the circuit case 20. The sector stopper 46 (see FIG. 2) is fixed.

Further, as shown in FIG. 2, a caster lever 47 is integrally provided with the caster lever 47 on the caster 9 for supporting the front wheel 6. These caster levers 47 extend toward the front inside, and the tip end portions of both caster levers 47 and the left and right tip end portions of the sector arm 43 are connected by tie rods 48.

The steering mechanism section 40 is constructed as described above, and a motor unit serving as a power source of the steering mechanism section 40.
50 is supported on the motor plate 21. As shown in the enlarged view of FIG. 9, the motor unit 50 is a unit in which a motor section 51 and a reduction section 52 are integrated.
Three fixing portions 53 provided around 52 are overlapped on the motor unit mounting hole 38 of the motor plate 21, and bolts 54 (shown in FIG. 3) are fastened and fixed from below the motor plate 21. .

A worm gear 56 is attached to the main shaft 55 of the motor unit 51.
Is formed, and this worm gear 56 meshes with a large-diameter reduction gear 57 built in the reduction portion 52. On the lower surface of the reduction gear 57, a small-diameter output gear 58 is integrally provided for rotation,
The output gear 58 projects from the lower surface of the reduction gear 52, is exposed from the gear hole 37 of the motor plate 21 to the lower surface of the motor plate 21, and meshes with the sector gear 42 of the sector gear arm 41.

When the motor section 51 of the motor unit 50 operates, the rotation of the main shaft 55 drives the reduction gear 57 to output the output gear.
58 is rotated, and the rotation of the output gear 58 is transmitted to the sector gear 42 to rotate the sector gear arm 41. The rotation of the sector gear arm 41 is performed by the tie rod 48 through the left and right front wheels 6
The left and right front wheels 6 are simultaneously transmitted to the (caster 9) in the same direction to determine the traveling direction of the electric wheelchair 1.

A steering angle sensor 60 for detecting the steering angle of the front wheels 6 is provided in the circuit case 20. As shown in FIGS. 3 and 5, the circuit case 20
A fixing protrusion 61 is integrally formed in the vicinity of the boss 24, and the steering angle sensor 60 is fixed to the lower surface of the other end of a sensor fixing plate 63 fixed to the fixing protrusion 61 with a bolt 62.

The sensor driven gear 65, which is provided integrally with the rotary shaft 64 of the steering angle sensor 60, is engaged with the sensor drive gear 45 provided on the sector shaft 44, and the amount of rotation of the sector gear arm 41, that is, The steering angle of the front wheels 6 is transmitted to the steering angle sensor 60 via the sensor drive gear 45 and the sensor driven gear 65. In this way, the sensor drive gear 45 and the sensor driven gear
The reference numeral 65 functions as a steering angle transmission means for transmitting the rotation amount of the rotation shaft (sector shaft 44) of the steering mechanism section 40 to the steering angle sensor 60.

Further, as shown in FIGS. 2 to 4, two large and small electronic boards 67 and 68 are installed in the circuit case 20. These two electronic boards 67 and 68 are used for the steering command from the control box 12 (steering lever 15) and the steering angle sensor.
The operation of the motor unit 50 is controlled based on the steering angle data of the front wheels 6 input from 60.

The large electronic board 67 is arranged in the center of the circuit case 20, and its four corners are fastened to the four bosses 70 in the circuit case 20 with screws 69. In addition, the small electronic board 68 is a step portion provided on the right end side of the circuit case 20.
It is arranged on 71, and both ends thereof are fastened to the circuit case 20 with screws 72. Note that a plurality of heat radiation fins 73 are formed on the lower surface of the stepped portion 71 (see also FIG. 5), and the heat radiated by the heat generating portion such as a power transistor provided on the small electronic board 68 is radiated from the heat radiation fins 73. It is supposed to be done.

A box-shaped cover member having a downward opening
75 is mounted on the circuit case 20 and the motor plate 21 (see FIGS. 2 and 4). This cover member 75 is
As shown in FIGS. 10 and 11, a flat top plate 76, a front plate 77 hanging from the front edge of the top plate 76, and short side plates 78 located on the left and right of the top plate 76 are provided. Further, a frame portion 79 that is closely fitted to the circuit case 20 is provided on the lower surface of the top plate 76. Engaging claws 80 are formed at four locations on the frame 79, and the engaging claws 80 are locked to the engaging stepped portions 81 provided on the peripheral surface of the circuit case 20 to cover the cover. The member 75 is positioned and the inside of the circuit case 20 is waterproofed.

The cover member 75 is made of a non-metal material such as plastic, and the inner area of the frame portion 79 is covered with a metal plate 82 having the same shape. This metal plate 82
Is fixed in the frame 79 by adhesion or fitting, but the metal plate 82 may be embedded inside when the cover member 75 is molded with resin.

The frame 79 of the cover member 75 is the circuit case
When fitted to the circuit case 20, the upper opening of the circuit case 20 is closed by the metal plate 82, so that the electronic boards 67 and 68 housed in the circuit case 20 are greatly improved in resistance to electromagnetic interference. . Further, since the cover member 75 is made of synthetic resin and the metal plate 82 is small, it is possible to reduce the weight of the cover member 75.

In the power steering device 11 configured as described above, as described above, the box-shaped circuit case 20 made of metal and opening upward is installed on the steering mechanism section 40, and Electronic board 67,6 in case 20
8 and the steering angle sensor 60 are arranged, and the steering mechanism
The sector shaft 44, which is the axis of rotation of 40, is the circuit case
It is introduced from below into the inside of the shaft 20, and the rotation amount of the sector shaft 44 is transmitted to the steering angle sensor 60 by the sensor drive gear 45 and the sensor driven gear 65.

Due to this structure, the circuit case 20 makes the electronic boards 67, 68 and the steering angle sensor 60 waterproof, and
The electronic boards 67 and 68 are significantly improved in the resistance to electromagnetic interference. In particular, since the introduction portion of the sector shaft 44 is on the lower surface of the circuit case 20, it is difficult to be exposed to the wind and rain, and excellent waterproofness is brought about.

Further, the circuit case 20 and the motor plate 21 supporting the motor unit 50 are connected side by side in the vehicle width direction, and the outer end portion of the circuit case 20 and the outer end portion of the motor plate 21 are attached to the body frame 2. Since the connecting portions 25, 30 to the left and right vertical frame members 17L, 17R are provided, the entire power steering device 11 is unitized.

Therefore, the four bolts 26 and 31 for fixing the connecting portions 25 and 30 on both sides to the vertical frame members 17L and 17R and the one bolt 29 for fixing the circuit case 20 to the horizontal frame member 18 are attached and detached. Power steering device 11
The whole body can be easily attached to and detached from the vehicle body frame 2 and the maintainability is greatly improved. Also, in an electric wheelchair that is not equipped with a power steering device, a large number of bolt holes need only be machined in the vehicle body frame to create a large scale. The power steering device can be mounted without any special modification.

Further, the body frame 2 is constructed in a ladder shape lying horizontally, and its vertical frame members 17L, 17
Since the circuit case 20 and the motor plate 21 are arranged between the R overhang portions, the devices constituting the power steering device 11 do not project from the outer peripheral contour of the vehicle body frame 2 and therefore are not connected to external objects. The damage due to the collision can be avoided, and since the power steering device 11 is not arranged inside the larger than the outer peripheral contour of the vehicle body frame 2, good maintainability can be maintained.

[0043]

As described above, in the power steering device for an electric wheelchair according to the present invention, a box-shaped circuit case made of metal and having an opening at the top is installed on the steering mechanism part, and the box-shaped circuit case is installed in the circuit case. The electronic board and the steering angle sensor are arranged, and the turning shaft of the steering mechanism is introduced from below into the circuit case, and the steering angle transmitting means for transmitting the turning amount of the turning shaft to the steering angle sensor is provided in the circuit case. Since it is provided in the electronic circuit board, the waterproofness of the electronic circuit board and the steering angle sensor and the electromagnetic wave resistance of the electronic circuit board can be improved.

In the power steering device for an electric wheelchair according to the present invention, the circuit case and the motor plate supporting the motor unit are connected side by side in the vehicle width direction, and the outer end portion of the circuit case and the outer end portion of the motor plate are connected. Since the connection part to the vehicle body frame is provided on the and, the power steering device is unitized as a whole to facilitate attachment / detachment to / from the vehicle body frame, improve maintainability, and make a major modification to the electric wheelchair without the power steering device. The power steering device can be installed without need.

Further, in the power steering device for an electric wheelchair according to the present invention, the body frame is constructed in a horizontally lying ladder type, and the circuit case and the motor plate are arranged between the overhang portions of the left and right vertical frame members. Therefore, it is possible to prevent the devices constituting the power steering device from colliding with an external object and being damaged without impairing maintainability.

In the power steering device for an electric wheelchair according to the present invention, a box-shaped cover member having a downward opening is mounted from above the circuit case and the motor plate, and the circuit board is provided on the lower surface of the top plate of the cover member. Since the frame portion that tightly fits in the case is provided, the waterproofness inside the circuit case can be significantly improved.

In the power steering device for an electric wheelchair according to the present invention, the cover member is made of a non-metal material,
Since the inner area of the frame portion is covered with the metal plate, it is possible to improve the electromagnetic wave resistance of the electronic board housed in the circuit case without increasing the weight of the cover member.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electric wheelchair to which a power steering device according to the present invention is applied, as seen from diagonally right front.

FIG. 2 is a plan view showing a front portion of a vehicle body frame, front wheels, and a power steering device.

FIG. 3 is a perspective view of the power steering device as viewed from diagonally left rear.

4 is a vertical cross-sectional view of the power steering device taken along the line IV-IV in FIG.

FIG. 5 is a plan view of a circuit case.

FIG. 6 is a plan view of a motor plate.

FIG. 7 is a plan view of a sector gear arm.

8 is a vertical cross-sectional view of the sector gear arm taken along the line VIII-VIII in FIG.

FIG. 9 is a plan view of a motor unit.

FIG. 10 is a bottom view of the cover member.

11 is a vertical cross-sectional view of the cover member taken along the line XI-XI of FIG.

[Explanation of symbols]

 1 Electric Wheelchair 2 Body Frame 6 Front Wheels that are Steering Wheels 11 Power Steering Device 17L, 17R Vertical Frame Member 20 Circuit Case 21 Motor Plate 25, 30 Coupling Section 40 Steering Mechanism Section 44 Sector Shaft that is the Rotating Shaft of the Steering Mechanism Section 50 Motor unit 60 Steering angle sensor 45 Sensor drive gear constituting steering angle transmission means 65 Sensor driven gear constituting steering angle transmission means 67,68 Electronic board 75 Cover member 76 Top plate 79 Frame 82 Metal plate

Claims (5)

[Claims] 1. A steering mechanism section 40 for steering steered wheels (front wheels 6), a motor unit 50 as a power source of the steering mechanism section 40, and electronic boards 67, 68 for controlling the operation of the motor unit 50. , Electronic board 67,68 by detecting the steering angle of the steering wheel
In a power steering device for an electric wheelchair equipped with a steering angle sensor 60 for input to a steering wheel, a box-shaped circuit case 20 made of metal and opening upward is installed on the steering mechanism section 40, and an electronic device is installed in the circuit case 20. The boards 67, 68 and the steering angle sensor 60 are arranged, and the turning shaft (sector shaft 44) of the steering mechanism section 40 is introduced into the circuit case 20 from below, and the turning amount of this turning shaft is determined by the steering angle sensor 60. 11. A power steering device for an electric wheelchair characterized in that a steering angle transmitting means (sensor drive gear 45, sensor driven gear 65) for transmitting to a vehicle is provided in the circuit case 20. 2. The circuit case 20 and a motor plate 21 supporting the motor unit 50 are connected side by side in the vehicle width direction, and the outer end of the circuit case 20 and the outer end of the motor plate 21 are connected to the body frame 2. The power steering device 11 for an electric wheelchair according to claim 1, wherein the connecting portions 25, 30 are provided. 3. The circuit frame 20 and the motor plate 21 are arranged between the overhang portions of the left and right vertical frame members 17L and 17R, wherein the body frame 2 is formed in a horizontally lying ladder type. Power steering device for electric wheelchair 11. 4. A box-shaped cover member 75 opening downward,
The electric wheelchair according to any one of claims 1 to 3, wherein the circuit case (20) and the motor plate (21) are covered from above, and a frame portion (79) tightly fitted to the circuit case (20) is provided on a lower surface of a top plate (76) of the cover member (75). Power steering device 11. 5. The steering device 11 for an electric wheelchair according to claim 4, wherein the cover member 75 is made of a non-metallic material, and an inner area of the frame portion 79 is covered with a metal plate 82.