JP3531327B2 - Power steering device for electric wheelchair - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering device for an electric wheelchair. [0002] Some electric wheelchairs that are driven by the power of an electric motor are equipped with a power steering device. This power steering device is configured to steer the steered wheels (generally the front wheels) with the power of a motor unit that is different from the electric motor for traveling. A steering mechanism that steers the wheel, an electronic board that controls the operation of the motor unit, and a steering angle sensor that detects the steering angle of the steering wheel and inputs the steering angle to the electronic board are provided. These devices are all installed in the vicinity of the steering wheel, that is, in front of the lower part of the seating seat, and each component is individually fixed to the vehicle body frame. However, since the lower front part of the seating seat is close to the traveling road surface and is easily exposed to wind and rain, when the power steering device is installed at this position, particularly the electronic board and the steering angle sensor. It is necessary to ensure waterproofness. At the same time, it is necessary to ensure the radio wave resistance of the electronic board. Further, since a plurality of devices constituting the power steering device are individually fixed to the vehicle body frame in front of the lower part of the seating seat, it is difficult to attach and detach the entire power steering device, and maintenance is very easy. In addition, when a power steering device is mounted 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 body frame by welding or the like, which requires major modifications. It was. In addition, there is a portion where the equipment constituting the power steering device protrudes from the outer peripheral contour of the body frame, and there is a high possibility that this portion will collide with an external object and be damaged. If the entire power steering device is disposed on the inner side of the outer peripheral contour of the vehicle body frame, it becomes difficult to attach and detach each portion, and the maintainability is 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 the electronic board and the steering angle sensor and the radio wave resistance of the electronic board. An object of the present invention is to provide a power steering device for an electric wheelchair. Further, the second object of the present invention is to improve the maintainability by making it easy to attach and detach the entire power steering device, and to power steering without requiring a large-scale modification to an electric wheelchair without the power steering device. It is to make the device mountable. A third object of the present invention is to make it possible to prevent equipment constituting the power steering apparatus from colliding with an external object and being damaged without impairing maintainability. [0009] [Means for Solving the Problems] To achieve the above object, a power steering apparatus for an electric wheelchair according to the present invention, a steering mechanism for steering the steering helm, and a power source for the steering mechanism An electric wheelchair comprising: a motor unit comprising: an electronic board that controls the operation of the motor unit; and a steering angle sensor that detects the steering angle of the steered wheels and inputs the detected steering angle to the electronic board to control the operation of the motor unit. In the power steering apparatus, the steering mechanism section includes
Secure to the motor plate that supports the motor unit.
The rotating shaft is inserted into the specified sleeve.
A steered wheel is supported as a central part of the steering mechanism.
While providing the sector gear arm to rotate, set up a box-shaped circuit case which is open upward in a metal on top of the steering mechanism, as well as arranging the steering angle sensor and the electronic substrate within the circuit case, circuit and the case,
Coupled side by side the M o ter plates in the vehicle width direction, the connection to the vehicle body frame provided on an outer end portion of the outer end and the motor plate circuit case, the sector gear arm
Together with the motor plate sleeve
Boss formed into a cylindrical shape penetrating the floorboard of the case case
And insert the upper end of the pivot shaft into the circuit case
The steering angle is detected from the amount of rotation of this rotation shaft.
The steering angle sensor and the rotation amount of the rotation shaft are used as the steering angle sensor.
A steering angle transmission means to transmit to the circuit is installed in the circuit case.
I did it. [0014] 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 a power steering apparatus according to the present invention is applied as viewed from the right front side. The electric wheelchair 1 includes a body frame 2 made of, for example, a pipe. A seating seat 3 is installed on the top of the body frame 2, and armrests 4 are provided on the left and right sides of the seating seat 3. Yes. A rear wheel 5 as a drive wheel is pivotally supported at the rear lower part of the vehicle body frame 2, and a front wheel 6 as a steering wheel is provided at the front lower part of the vehicle body frame 2. A footrest 7 is provided in front of the front wheel 6. A power unit 8 in which a traveling electric motor and a power source battery are integrally formed is mounted below the seating seat 3, and the rear wheel 5 is driven by the power unit 8. It is like that. On the other hand, the front wheel 6 is supported by casters 9 so as to be able to turn 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 part of the seating seat 3. ing. This power steering device 11 performs a steering operation of the front wheels 6. For example, the right armrest 4 has a control box.
12, a travel speed adjustment switch 13, a forward / reverse switching switch 14 and the like are disposed on the upper surface of the control box 12, and a steering lever 15 for setting a traveling direction is disposed on the front surface of the control box 12. Is provided. When the steering lever 15 is turned left and right, the power steering device 11 steers the front wheel 6 according to the turning direction and the turning amount, and the traveling direction of the electric wheelchair 1 is determined. FIG. 2 is a plan view showing the front portion of the body frame 2, the front wheels 6, and the power steering device 11. As shown in FIG. As shown in this figure, the body frame 2 is configured 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 front ends of the vertical frame members 17L and 17R. As shown in FIGS. 3 and 4,
The power steering device 11 includes a box-shaped circuit case 20 made of metal and opened upward, and a motor plate 21 made of sheet metal press. The circuit case 20 and the motor plate 21 are connected side by side in the vehicle width direction, and 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.
Is disposed between the portions extending forward from the most lateral frame member 18. The circuit case 20 is disposed on the right side in the traveling direction, and the motor plate 21 is disposed 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. A bay portion 23 is formed at the end on the left side in the advancing direction, and a cylinder is formed in front of the circuit case 20. A boss 24 is integrally formed so as to penetrate the floor board. 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 fixing bracket 27 and a fixing bracket 28 are provided at the rear edge portion and the left end portion of the circuit case 20, respectively.
To be fixed to the horizontal frame member 18. On the other hand, as shown in FIGS. 4 and 6, the motor plate 21 is formed with a pair of front and rear connecting portions 30 at the end on the left side in the traveling direction. Fastened to the vertical frame member 17L. Also, the motor plate 21 is formed with two fastening pieces 32, 33, and the fastening piece 32 is a circuit case 20 with a bolt 34.
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 from below into the boss 24 of the circuit case 20 when the motor plate 21 is connected to the circuit case 20. In the vicinity of the sleeve 36, a gear hole 37 and three motor unit mounting holes 38 surrounding the gear hole 37 are formed. Below the circuit case 20 and the motor plate 21, there is provided a steering mechanism 40 for steering the front wheels 6 as steering wheels (see FIG. 2). The steering mechanism 40 is configured as follows, for example. First, a sector gear arm 41 that forms the center of the steering mechanism 40 is pivotally supported on 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 fixed through the central portion of the sector gear 42 are assembled. The sector shaft 44, which serves as the rotation axis of the steering mechanism 40, is inserted into the sleeve 36 of the motor plate 21 from below and can rotate smoothly without play. Therefore, the entire sector gear arm 41 can freely rotate about the sector shaft 44. A sensor drive gear 45 that also serves to prevent the sector gear arm 41 from coming off is provided at the upper end of the sector shaft 44, and the rotation angle of the sector gear arm 41 is regulated on the lower surface of the circuit case 20. A sector stopper 46 (see FIG. 2) is fixed. As shown in FIG. 2, a caster lever 47 is pivotally integrated with the caster 9 that supports the front wheel 6. These caster levers 47 extend inward and forward, respectively, and the tip portions of both caster levers 47 and the left and right tip portions of the sector arm 43 are connected by tie rods 48. The steering mechanism section 40 is configured as described above, and a motor unit serving as a power source for the steering mechanism section 40.
50 is supported on the motor plate 21. As shown in an enlarged view in FIG. 9, the motor unit 50 has a motor part 51 and a speed reduction part 52 integrated with each other.
Three fixing portions 53 provided around 52 are superposed 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. . The main shaft 55 of the motor unit 51 has a worm gear 56.
The 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 provided integrally with the rotation,
The output gear 58 protrudes from the lower surface of the speed reducing portion 52 and is further 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 unit 51 of the motor unit 50 is activated, the rotation of the main shaft 55 drives the reduction gear 57 to output gear.
The rotation of the output gear 58 is transmitted to the sector gear 42 and the sector gear arm 41 is rotated. The sector gear arm 41 is rotated through the tie rod 48 to the left and right front wheels 6.
The left and right front wheels 6 are simultaneously rotated in the same direction to determine the traveling direction of the electric wheelchair 1. Incidentally, 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 FIG. 3 and FIG.
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 the sensor fixing plate 63 fixed to the fixing protrusion 61 with a bolt 62. A sensor driven gear 65 provided integrally with the rotating shaft 64 of the steering angle sensor 60 meshes with a 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. Thus, sensor drive gear 45 and sensor driven gear
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 substrates 67 and 68 are installed in the circuit case 20. The two electronic boards 67 and 68 are provided with a steering command from the control box 12 (steering lever 15) and a 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 at the center of the circuit case 20, and its four corners are fastened to four bosses 70 in the circuit case 20 with screws 69. In addition, the small electronic board 68 is a step 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. A plurality of radiating fins 73 are formed on the lower surface of the stepped portion 71 (see also FIG. 5), and heat radiated from a heat generating portion such as a power transistor provided on the small electronic substrate 68 is radiated from the radiating fins 73. It has come to be. A box-shaped cover member opening downward
75 is mounted on the circuit case 20 and the motor plate 21 (see FIGS. 2 and 4). This cover member 75
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. In addition, a frame portion 79 is provided on the lower surface of the top plate 76 so as to be closely fitted to the circuit case 20. Engaging claws 80 are formed at four positions on the frame portion 79, and these engaging claws 80 are engaged with an engaging step portion 81 provided on the peripheral surface of the circuit case 20 to cover the frame portion 79. The member 75 is positioned, and the inside of the circuit case 20 is waterproofed. The cover member 75 is made of a non-metallic material such as plastic, and the area inside the frame portion 79 is covered with a metal plate 82 having the same shape. This metal plate 82
Is fixed in the frame portion 79 by adhesion or fitting, but the metal plate 82 may be embedded inside the cover member 75 during resin molding. The frame portion 79 of the cover member 75 is a circuit case.
When fitted to 20, the upper opening of the circuit case 20 is blocked by the metal plate 82, so that the resistance to radio interference of the electronic boards 67 and 68 accommodated in the circuit case 20 is greatly improved. . Further, since the cover member 75 is made of synthetic resin and the metal plate 82 is small, the cover member 75 can be reduced in weight. As described above, the power steering device 11 configured as described above includes a box-shaped circuit case 20 that is made of metal and opens upward. Electronic board 67,6 in case 20
8 and the steering angle sensor 60 are disposed, and the steering mechanism section
Sector shaft 44, which is the 40 rotation axis, is the circuit case
The rotation amount of the sector shaft 44 is introduced into the inside 20 and transmitted to the steering angle sensor 60 by the sensor drive gear 45 and the sensor driven gear 65. Because of this structure, the circuit case 20 allows the electronic boards 67 and 68 and the steering angle sensor 60 to be waterproof,
The radio wave resistance of the electronic boards 67 and 68 is greatly improved. In particular, since the introduction portion of the sector shaft 44 is located on the lower surface of the circuit case 20, it is difficult to be exposed to wind and rain, resulting in excellent waterproofness. The circuit case 20 and the motor plate 21 that supports the motor unit 50 are connected side by side in the vehicle width direction, and the body frame 2 is connected to the outer end of the circuit case 20 and the outer end of the motor plate 21. 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. For this reason, 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 one bolt 29 for fixing the circuit case 20 to the horizontal frame member 18 are attached and detached. Just power steering device 11
The whole body can be easily attached to and detached from the body frame 2 and the maintainability is greatly improved. For an electric wheelchair that does not have a power steering device, a large number of bolt holes are simply formed in the body frame. The power steering device can be installed without requiring any remodeling. Further, the vehicle body frame 2 is constructed in a ladder shape which lies horizontally, and its vertical frame members 17L, 17
Since the circuit case 20 and the motor plate 21 are disposed between the overhang portions of the R, the devices constituting the power steering device 11 do not protrude from the outer peripheral contour of the vehicle body frame 2, so Can be avoided, and the power steering device 11 is not arranged on the inner side of the outer contour of the vehicle body frame 2 so that the maintainability can be kept good. As described above , according to the power steering device for an electric wheelchair according to the present invention, the waterproofness of the electronic board and the steering angle sensor and the radio wave resistance of the electronic board are improved. At the same time, the entire power steering device is unitized to make it easy to attach and detach to the body frame to improve maintainability, and the power wheelchair without the power steering device can be installed without requiring major modifications. be able to. [0045]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an electric wheelchair to which a power steering apparatus according to the present invention is applied as viewed from the right front side. 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 the left rear side. 4 is a longitudinal sectional view of the power steering device taken along line IV-IV in FIG. 2; 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 longitudinal sectional view of the sector gear arm taken along line VIII-VIII in FIG. FIG. 9 is a plan view of the motor unit. FIG. 10 is a bottom view of a cover member. 11 is a longitudinal sectional view of a cover member taken along line XI-XI in FIG. [Explanation of Symbols] 1 Electric wheelchair 2 Body frame 6 Front wheel 11 which is a steering wheel Power steering device 17L, 17R Vertical frame member 20 Circuit case 21 Motor plate 25, 30 Connecting portion 40 Steering mechanism portion 44 Rotating shaft of the steering mechanism portion Sector shaft 50 Motor unit 60 Steering angle sensor 45 Sensor drive gear 65 constituting steering angle transmission means Sensor driven gear 67,68 constituting steering angle transmission means Electronic board 75 Cover member 76 Top plate 79 Frame portion 82 Metal plate

Continuation of front page (56) References JP-A-1-269671 (JP, A) JP-A-59-10103 (JP, A) JP-A-58-177651 (JP, A) JP-A-54-103291 (JP) , A) Japanese Patent Publication Sho 63-53180 (JP, A) Japanese Utility Model Sho 58-133329 (JP, U) Japanese Patent Publication Sho 61-55387 (JP, B1) Japanese Patent Publication Sho 30-30773 (JP, B1) 1-36689 (JP, Y2) Special Table 60-500435 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) A61G 5/04

Claims (1)

(57) [Claims] [Claims] [Claims] [Claims] [Claims] [Claim 1] Steering mechanism for steering a steering wheel, a motor unit as a power source of the steering mechanism, an electronic board for controlling the operation of the motor unit, steering and input to the electronic board to detect a steering angle of the wheels, the electric wheelchair of the power steering device including a steering angle sensor for controlling the actuation of the motor unit to the electronic board, the steering engine
The structure has a motor plug that supports the motor unit.
The rotating shaft is inserted into the sleeve fixed to the rate.
And pivotally supported by the center of the steering mechanism.
While providing a sector gear arm that rotates the steering wheel,
The box-shaped circuit case which is open upward in a metal was placed on the steering mechanism, as well as arranging the steering angle sensor and the electric <br/> element substrate in this circuit case, and circuit case, the motor over coater plates side by side in the vehicle width direction are connected, the connection to the vehicle body frame provided on an outer end portion of the outer end and the motor plate circuit case, the sector
The rotation axis of the gear arm and the sleeve of the motor plate
Formed in a cylindrical shape that penetrates the floor of the circuit case
Insert the bottom end of the rotating shaft into the boss
The steering angle is calculated from the amount of rotation of this rotating shaft.
The steering angle sensor for detecting
The steering angle transmission means for transmitting to the steering angle sensor is a circuit cable.
A power steering device for an electric wheelchair characterized by being provided in a chassis.