CN110575327A

CN110575327A - Balance wheelchair

Info

Publication number: CN110575327A
Application number: CN201910972018.0A
Authority: CN
Inventors: 闫学堂
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2019-12-17

Abstract

The invention discloses a balance wheelchair, which belongs to the field of vehicles and comprises a wheelchair frame, a crawler traveling mechanism, a steering mechanism, a limiting mechanism, a seat, a self-locking rotation driving device and an electric cabinet, wherein the wheelchair frame comprises a lower supporting frame and supporting columns, the steering mechanism controls the crawler traveling mechanism to steer, a lower connecting rod is hinged between the two supporting columns, a U-shaped plate is fixed at the top ends of the two supporting columns, the U-shaped plates are connected through an upper connecting rod, the U-shaped plate, the lower connecting rod and the supporting columns form a four-bar mechanism together, and a positioning mechanism for limiting the deformation of the four-bar mechanism is installed on the supporting columns. When the wheelchair passes through a section with uneven pits or an obstacle section, the self-locking rotary driving device can automatically keep balance, when the inclination angle of the wheelchair exceeds a preset angle, the self-locking rotary driving device pulls the deflector rod through the chain, so that the four-bar mechanism deforms, the seat is kept horizontal, the wheelchair is prevented from turning on one side, and the wheelchair can easily cross obstacles, climb steps and descend steps through the crawler traveling mechanism.

Description

balance wheelchair

Technical Field

The invention relates to the field of vehicles, in particular to a balance wheelchair.

background

In the current society, the electric wheelchair has become a tool for walking instead of walking for some disabled people and old people, the electric wheelchair is suitable for walking on a flat road, but the electric wheelchair cannot always be a flat road when actually walking, and can run into an uphill road, a downhill road and some convex or concave roads in the walking process, so that the electric wheelchair cannot keep balance when passing through the road conditions, jolt and uncomfortable for passengers, and side turning can possibly occur.

When the electric wheelchair is used, the electric wheelchair is easy to lean backwards on the uphill and downhill road sections, and is easy to topple over when the lean angle is too large, so that continuous and stable climbing is difficult to realize when climbing steps, and people on the wheelchair cannot keep a horizontal sitting posture when the climbing angle is slightly large, and the electric wheelchair is easy to topple over when leaning backwards.

disclosure of Invention

in order to solve the problems, the invention designs a balance wheelchair, which adjusts a seat in real time according to the inclination angle of the seat so as to keep a passenger on the wheelchair in a horizontal sitting posture.

The technical scheme of the invention is that the balance wheelchair comprises a wheelchair frame, a crawler traveling mechanism, a steering mechanism, a limiting mechanism, a seat and an electric cabinet, wherein the wheelchair frame comprises a lower support frame and support columns, the crawler traveling mechanism is arranged at the bottom of the lower support frame, the steering mechanism for controlling the steering of the crawler traveling mechanism is arranged at the lower end of the lower support frame, two parallel support columns are fixed at the upper end of the lower support frame, a lower connecting rod is hinged between the two support columns, a U-shaped plate is fixed at the top ends of the two support columns, a first hinge shaft, a fixed shaft, a locking shaft and an inner slide plate are arranged in the U-shaped plate, the two first hinge shafts are connected through an upper connecting rod, the U-shaped plate, the lower connecting rod and the support columns form a four-bar mechanism together, and a positioning mechanism for limiting the deformation of the, a deflector rod is arranged on the fixed shaft, one end of the deflector rod is fixed with a chain fixing ring, and the other end of the deflector rod is provided with a locking part; a mounting bottom plate is fixed on the lower connecting rod, a self-locking rotation driving device is mounted on the mounting bottom plate, a chain wheel is mounted at the rotation end of the self-locking rotation driving device, the two chain fixing rings are connected with the chain wheel through chains in a tensioning mode, the two inner supporting sliding plates are connected with a bottom plate in a sliding mode, locking heads matched with the locking shafts are fixed at two ends of the bottom plate, and the bottom plate is fixedly connected with a seat through a connecting plate; the electric cabinet is arranged on the lower support frame, an angle sensor is arranged in the electric cabinet, and the electric cabinet is electrically connected with the crawler traveling mechanism, the steering mechanism, the limiting mechanism, the self-locking rotary driving device and the angle sensor.

Further, track running gear's quantity is three, track running gear includes U type support, bearing axle, mounting bracket, action wheel, follows driving wheel, track, driving motor, synchronous pulley and synchronous cog belt, but bearing axle rotatable installs between U type support, bearing axle both ends and mounting bracket fixed connection, install driving motor, action wheel and a plurality of follow driving wheel on the mounting bracket, all install synchronous pulley, two on action wheel and driving motor's the output shaft synchronous pulley is connected through synchronous cog belt transmission between the synchronous pulley, and the track is connected with action wheel and a plurality of follow driving wheel transmissions.

Further, one of them crawler travel mechanism of steering mechanism control turns to, steering mechanism includes the mounting panel, turns to motor, pinion, gear wheel and vertical scroll, open the bottom of the under bracing frame has the mounting groove, but the rotatable vertical scroll of installing in the mounting groove, the mounting panel is installed to the under bracing frame lower extreme, install on the mounting panel and turn to the motor, turn to and install the pinion on the motor output shaft, the gear wheel of being connected with the pinion meshing is installed to the vertical scroll lower extreme, the vertical scroll lower extreme with this crawler travel mechanism's U type support fixed connection, all the other two crawler travel mechanism's U type support is installed in the under bracing frame bottom.

Further, two all install positioning mechanism on the support column, positioning mechanism includes second articulated shaft, position sleeve, adjusting screw, slip spring holder, spring, steel ball, it has the draw-in groove of two symmetric distributions to open on the support column, rotatable the installation has the second articulated shaft in the support column, second articulated shaft both ends stretch out the support column and are fixed with the position sleeve, it has the spout of perpendicular and support column to open in the position sleeve, slidable mounting has the slip spring holder in the spout, the slip spring holder is fixed with the spring towards the one end of support column, the steel ball with the draw-in groove joint is installed to the spring other end, threaded connection has adjusting screw on the position sleeve, in the adjusting screw one end screw in spout with the butt of slip spring holder, the connecting rod is fixed on the position sleeve down.

Furthermore, the U-shaped plate is composed of a horizontal connecting plate and side vertical plates fixed on two sides of the horizontal connecting plate.

Further, the seat comprises a seat plate, armrests, a backrest, a baffle and pedals, the seat plate is fixed on the connecting plate, the backrest is fixed on one side of the seat plate, the baffle is fixed on the other side of the seat plate, the armrests are fixed on the backrest and the seat plate, and the pedals are fixed at the lower end of the baffle.

Furthermore, the self-locking rotation driving device comprises an electric motor and a worm gear reducer, and the electric motor is in transmission connection with the worm gear reducer.

the invention has the beneficial effects that:

1. when the wheelchair passes through a section with uneven pits or a section with obstacles, the wheelchair can automatically keep balance, and when the inclination angle of the wheelchair exceeds a preset angle, the self-locking rotary driving device pulls the deflector rod through the chain to deform the four-bar mechanism, so that the seat and a rider on the seat are kept horizontal, the rider is prevented from leaning backwards, the wheelchair is prevented from turning over, and the wheelchair is more comfortable and safer;

2. The crawler traveling mechanism is arranged, so that the wheelchair can easily cross obstacles, climb steps and lower steps, is suitable for various terrains, and is convenient for adjusting the traveling direction of the wheelchair through the steering mechanism.

Drawings

FIG. 1 is a schematic structural view of a balance wheelchair of the present invention;

FIG. 2 is a side elevational view of a balance wheelchair of the present invention;

FIG. 3 is a first state view of a balance wheelchair of the present invention climbing a step;

FIG. 4 is a second state diagram of a balance wheelchair of the present invention in climbing steps;

FIG. 5 is a partial schematic view of the installation position of the self-locking rotation driving device of the balance wheelchair of the invention;

FIG. 6 is an enlarged view of a portion of FIG. 1 at A;

FIG. 7 is an enlarged view of a portion of FIG. 1 at B;

FIG. 8 is an enlarged view of a portion of FIG. 2 at C;

FIG. 9 is an enlarged view of a portion of FIG. 4 at D;

FIG. 10 is a first partial schematic view of the track undercarriage of the present invention;

FIG. 11 is a second partial schematic view of the crawler attachment of the present invention;

In the figure, 1, a wheelchair frame; 11. a lower support frame; 12. a support pillar; 121. a card slot; 13. a lower connecting rod; 131. mounting a bottom plate; 14. a U-shaped plate; 141. a horizontal connecting plate; 142. a side vertical plate; 15. a first hinge shaft; 16. a fixed shaft; 17. a locking shaft; 18. an inner support sliding plate; 19. an upper connecting rod; 2. a crawler travel mechanism; 21. a U-shaped bracket; 22. a load bearing shaft; 23. a mounting frame; 24. a driving wheel; 25. a driven wheel; 26. a crawler belt; 27. a drive motor; 28. a synchronous pulley; 29. a synchronous toothed belt; 3. a steering mechanism; 31. mounting a plate; 32. a steering motor; 33. a pinion gear; 34. a bull gear; 35. a vertical shaft; 36. mounting grooves; 4. a base plate; 41. a connecting plate; 42. a locking head; 5. a seat; 51. a foot pedal; 52. a seat plate; 53. a handrail; 54. a backrest; 55. a baffle plate; 6. an electric cabinet; 61. an angle sensor; 7. a positioning mechanism; 71. a second hinge shaft; 72. a positioning sleeve; 73. an adjusting screw; 74. a sliding spring seat; 75. a spring; 76. steel balls; 8. a deflector rod; 81. a chain fixing ring; 82. a locking portion; 9. a self-locking rotary drive device; 91. a sprocket; 92. a chain; 93. an electric motor; 94. worm gear reducer.

Detailed Description

The invention will be described in detail with reference to the accompanying drawings, as shown in fig. 1-11, a balance wheelchair comprises a wheelchair frame 1, a crawler walking mechanism 2, a steering mechanism 3, a bottom plate 4, a seat 5 and an electric cabinet 6, wherein the wheelchair frame 1 comprises a lower support 11 and support columns 12, the crawler walking mechanism 2 is mounted at the bottom of the lower support 11, the steering mechanism 3 for controlling the steering of the crawler walking mechanism 2 is mounted at the lower end of the lower support 11, two parallel support columns 12 are fixed at the upper end of the lower support 11, a lower connecting rod 13 is hinged between the two support columns 12, a U-shaped plate 14 is fixed at the top ends of the two support columns 12, a first hinge shaft 15, a fixed shaft 16, a locking shaft 17 and an inner sliding plate 18 are mounted in the U-shaped plate 14, the two first hinge shafts 15 are connected through an upper connecting rod 19, the U-shaped plate 14, a positioning mechanism 7 for limiting the deformation of the four-bar linkage is arranged on the supporting column 12, a deflector rod 8 is arranged on the fixed shaft 16, one end of the deflector rod 8 is fixed with a chain fixing ring 81, and the other end of the deflector rod 8 is provided with a locking part 82; a mounting bottom plate 131 is fixed on the lower connecting rod 13, a self-locking rotary driving device 9 is mounted on the mounting bottom plate 131, a chain wheel 91 is mounted at the rotating end of the self-locking rotary driving device 9, the shape of the lower connecting rod 13 is as shown in fig. 1, the center of the chain wheel 91 is positioned at the central point of the central connecting line of the two second hinge shafts 71, the two chain fixing rings 81 are connected with the chain wheel 91 in a tensioning manner through a chain 92, the two inner sliding plates 18 are connected with a bottom plate 4 in a sliding manner, locking heads 42 matched with the locking shafts 17 are fixed at two ends of the bottom plate 4, and the bottom plate; the electric cabinet 6 is arranged on the lower support frame 11, an angle sensor 61 is arranged in the electric cabinet 6, and the electric cabinet 6 is electrically connected with the crawler traveling mechanism 2, the steering mechanism 3, the self-locking rotary driving device 9 and the angle sensor 61.

As shown in fig. 2 and 5, the number of the crawler belt units 2 is three, as shown in fig. 6, 10 and 11, each crawler belt unit 2 includes a U-shaped bracket 21, a bearing shaft 22, a mounting bracket 23, a driving wheel 24, a driven wheel 25, a crawler belt 26, a driving motor 27, a synchronous pulley 28 and a synchronous cog belt 29, the bearing shaft 22 is rotatably mounted between the U-shaped brackets 21 through bearings, two ends of the bearing shaft 22 are fixedly connected with the mounting bracket 23, specifically, two ends of the bearing shaft 22 extend to the outer side wall of the mounting bracket 23 and are fixedly provided with blocking pieces, and the blocking pieces are fixedly connected with the bearing shaft 22 through screws, so that the bearing shaft 22 is fixedly connected with the mounting bracket 23; the mounting frame 23 is provided with a driving motor 27, a driving wheel 24 and a plurality of driven wheels 25, the driving motor 27 is fixedly mounted on the mounting frame 23, the driving wheel 24 and the plurality of driven wheels 25 are rotatably mounted on the mounting frame 23 through bearings, the output shafts of the driving wheel 24 and the driving motor 27 are respectively provided with a synchronous belt pulley 28, the two synchronous belt pulleys 28 are in transmission connection through a synchronous toothed belt 29, and the crawler belt 26 is in transmission connection with the driving wheel 24 and the plurality of driven wheels 25. The crawler belt traveling mechanisms 2 are internally provided with driving motors 27, all the driving motors 27 work synchronously to enhance the traveling capacity of the wheelchair, the driving motors 27 drive the driving wheels 24 to rotate through synchronous belt wheels 28 and synchronous toothed belts 29, and the driving wheels 24 drive the crawler belts 26 and the driven wheels 25 to move so as to realize the movement of the wheelchair; when the wheelchair passes through uneven road sections, the bearing shaft 22 is arranged, so that the mounting frame 23 can rotate relative to the U-shaped support 21, the bottom of the crawler belt 26 is in contact with the road surface, and the inclination angle of the wheelchair frame 1 is reduced.

the steering mechanism 3 controls one of the crawler belt traveling mechanisms 2 to steer, as shown in fig. 6, the steering mechanism 3 comprises a mounting plate 31, a steering motor 32, a pinion 33, a bull gear 34 and a vertical shaft 35; the bottom of the lower support frame 11 is provided with a mounting groove 36, a vertical shaft 35 is rotatably mounted in the mounting groove 36, specifically, two bearings are mounted in the mounting groove 36, the stand column is mounted in the two bearings, the bottom of the mounting groove 36 is fixedly provided with a plug, the bearing at the upper part is provided with an end cover, the end cover is fixedly connected with the stand column through a screw, the stand column can rotate relative to the wheelchair frame 1 through the arrangement of the two bearings, the plug is used for fixing the bearing at the lower part, and the end cover is used for fixing the top of the stand column, so that the stand column; the lower end of the lower support frame 11 is provided with an installation plate 31, the installation plate 31 is provided with a steering motor 32, the output shaft of the steering motor 32 is provided with a pinion 33, the lower end of a vertical shaft 35 is provided with a big gear 34 engaged and connected with the pinion 33, the lower end of the vertical shaft 35 is fixedly connected with the U-shaped support 21 of the crawler travelling mechanism 2, and the U-shaped supports 21 of the other two crawler travelling mechanisms 2 are arranged at the bottom of the lower support frame 11. The steering motor 32 is a stepping motor, when the steering motor 32 works, the small gear 33 is driven to rotate, the small gear 33 drives the large gear 34 and the vertical shaft 35 to rotate, the vertical shaft 35 drives the crawler traveling mechanisms 2 to rotate, steering is achieved, and after the steered crawler traveling mechanisms 2 move forwards, the other two crawler traveling mechanisms 2 can also follow the steering, and steering of the wheelchair is achieved.

the two supporting columns 12 are respectively provided with a positioning mechanism 7, as shown in fig. 8, each positioning mechanism 7 comprises a second hinge shaft 71, a positioning sleeve 72, an adjusting screw 73, a sliding spring 75 seat 74, a spring 75 and steel balls 76, the supporting columns 12 are provided with two clamping slots 121 which are symmetrically distributed, the second hinge shafts 71 are rotatably arranged in the supporting columns 12 through bearings, two ends of each second hinge shaft 71 extend out of the supporting column 12 and are fixedly provided with the positioning sleeves 72, sliding grooves which are vertical to the supporting columns 12 are formed in the positioning sleeves 72, the sliding spring 75 seats 74 are slidably arranged in the sliding grooves, one ends of the sliding spring 75 seats 74 facing the supporting columns 12 are fixedly provided with the springs 75, the other ends of the springs 75 are provided with the steel balls 76 which are clamped with the clamping slots 121, the positioning sleeves 72 are provided with internally threaded holes which are communicated with the sliding grooves, the adjusting screws 73 are in threaded connection with the internally threaded holes, the lower link 13 is fixed to the positioning sleeve 72. Under the action of the elastic force of the spring 75, one part of the steel ball 76 is positioned in the sliding groove, and the other part of the steel ball is pressed into the clamping groove 121, so that the positioning sleeve 72 is clamped with the supporting column 12, and the sliding spring 75 seat 74 slides in the sliding groove by rotating the adjusting screw 73, so that the compression amount of the spring 75 can be adjusted.

As shown in fig. 2, the U-shaped plate 14 is composed of a horizontal connecting plate 141 and side standing plates 142 fixed to both sides of the horizontal connecting plate 141.

as shown in fig. 1, the seat 5 includes a seat plate 52, armrests 53, a backrest 54, a baffle plate 55, and a footrest 51, the seat plate 52 is fixed to the horizontal connecting plate 41, the backrest 54 is fixed to one side of the seat plate 52, the baffle plate 55 is fixed to the other side of the seat plate 52, the armrests 53 are fixed to the backrest 54 and the seat plate 52, and the footrest 51 is fixed to the lower end of the baffle plate 55.

as shown in fig. 1 and 5, the self-locking rotation driving device 9 includes an electric motor 93 and a worm gear reducer 94, and the electric motor 93 is in transmission connection with the worm gear reducer 94. The motor 93 is a stepping motor, can accurately control the rotation angle, is convenient for pulling the deflector rod 8 to move, and realizes the self-locking function by arranging the worm gear reducer 94.

The working principle of the embodiment is as follows: a storage battery and a control circuit board are arranged in the electric cabinet 6, power is supplied to each electric element through the storage battery, and the work of each electric element is controlled through the control circuit board; when the vehicle travels, the driving motors 27 synchronously output power to drive the caterpillar band 26 to move, so that the wheels travel;

When the wheelchair is steered, the electric control box 6 controls the steering motor 32 to output a certain angular displacement according to a steering angle required to steer, so as to drive the pinion 33 to rotate, the pinion 33 drives the gearwheel 34 and the vertical shaft 35 to rotate, the vertical shaft 35 drives the U-shaped bracket 21 connected with the vertical shaft to rotate, so that the crawler travelling mechanisms 2 rotate to steer, and after the steered crawler travelling mechanisms 2 move forwards, the other two crawler travelling mechanisms 2 can also steer along with the steering to steer the wheelchair;

when the vehicle travels to a pothole or an obstacle road section or climbs and descends, the angle sensor 61 detects the change of the angle and sends a signal to the electric cabinet 6, when the inclination angle exceeds a preset angle, in order to avoid the passenger from excessively leaning backwards and turning over, the control circuit board controls the motor 93 to rotate forwards or backwards, the motor 93 outputs a certain angular displacement, the speed is reduced by the worm gear reducer 94, and the output end of the worm gear reducer 94 drives the chain wheel 91 to rotate;

As shown in fig. 3 and 4, when the wheelchair climbs a left side step, the angle sensor 61 detects the inclination angle of the wheelchair frame 1, when the inclination angle exceeds a preset value, the sprocket 91 rotates clockwise, the chain 92 pulls the right shifter lever 8 to move, the right shifter lever 8 rotates by a certain angle, and the locking part 82 of the chain pushes the bottom plate 4 to move upwards and leftwards, so that the locking head 42 on the left side is positioned right below the locking shaft 17, the center of the sprocket 91 is always positioned at the central point of the connecting line of the centers of the two second hinge shafts 71, the elongation and the contraction of the left and right sides of the chain 92 are the same, the lower link 13 and the right lower column start to deform under the pulling force of the chain 92 due to the chain segment length of the chain 92 on the right side of the sprocket 91, the steel ball 76 is forced to be pressed into the chute and then separated from the clamping, the inner support sliding plate 18 on the left side supports the bottom plate 4 together, so that the bottom plate 4 is kept in a horizontal state;

When the steel ball passes through the step, the self-locking rotary driving device 9 drives the chain wheel 91 to rotate according to the detection data of the angle sensor 61, the length of the left chain segment and the right chain segment of the chain 92 is adjusted, when the steel ball passes through the step and travels to a flat section, the left supporting column 12 and the right supporting column 12 are restored to be in the equal height state, the upper connecting rod 19 and the lower connecting rod 13 are restored to be in the horizontal parallel state, and the lower connecting rod 13 drives the positioning sleeve 72 to rotate, so that the.

the technical solutions described above only represent the preferred technical solutions of the present invention, and some possible modifications to some parts of the technical solutions by those skilled in the art all represent the principles of the present invention, and fall within the protection scope of the present invention.

Claims

1. the balance wheelchair is characterized by comprising a wheelchair frame (1), a crawler traveling mechanism (2), a steering mechanism (3), a limiting mechanism (4), a seat (5) and an electric cabinet (6), wherein the wheelchair frame (1) comprises a lower support frame (11) and support columns (12), the crawler traveling mechanism (2) is installed at the bottom of the lower support frame (11), the steering mechanism (3) for controlling the crawler traveling mechanism (2) to steer is installed at the lower end of the lower support frame (11), two parallel support columns (12) are fixed at the upper end of the lower support frame (11), a lower connecting rod (13) is hinged between the two support columns (12), a U-shaped plate (14) is fixed at the top ends of the two support columns (12), a first articulated shaft (15), a fixed shaft (16), a locking shaft (17) and an inner articulated sliding plate (18) are installed in the U-shaped plate (14), the two first articulated shafts (15) are connected through an upper articulated shaft (19), the upper connecting rod (19), the U-shaped plate (14), the lower connecting rod (13) and the supporting column (12) form a four-bar mechanism together, a positioning mechanism (7) used for limiting deformation of the four-bar mechanism is mounted on the supporting column (12), a shifting rod (8) is mounted on the fixed shaft (16), a chain fixing ring (81) is fixed at one end of the shifting rod (8), and a locking part (82) is arranged at the other end of the shifting rod; a mounting bottom plate (131) is fixed on the lower connecting rod (13), a self-locking rotary driving device (9) is mounted on the mounting bottom plate (131), a chain wheel (91) is mounted at the rotary end of the self-locking rotary driving device (9), two chain fixing rings (81) are connected with the chain wheel (91) in a tensioning mode through chains (92), a bottom plate (4) is connected onto the two inner supporting sliding plates (18) in a sliding mode, locking heads (42) matched with the locking shafts (17) are fixed at two ends of the bottom plate (4), and the bottom plate (4) is fixedly connected with the seat (5) through a connecting plate (41); the electric cabinet (6) is installed on the lower support frame (11), an angle sensor (61) is arranged in the electric cabinet (6), and the electric cabinet (6) is electrically connected with the crawler traveling mechanism (2), the steering mechanism (3), the limiting mechanism (4), the self-locking rotary driving device (9) and the angle sensor (61).

2. The balance wheelchair as claimed in claim 1, wherein the number of the crawler belt walking mechanisms (2) is three, each crawler belt walking mechanism (2) comprises a U-shaped support (21), a bearing shaft (22), a mounting frame (23), a driving wheel (24), a driven wheel (25), a crawler belt (26), a driving motor (27), a synchronous pulley (28) and a synchronous toothed belt (29), the bearing shaft (22) is rotatably mounted between the U-shaped supports (21), two ends of the bearing shaft (22) are fixedly connected with the mounting frame (23), the mounting frame (23) is provided with the driving motor (27), the driving wheel (24) and the driven wheels (25), the output shafts of the driving wheel (24) and the driving motor (27) are provided with the synchronous pulleys (28), and the two synchronous pulleys (28) are in transmission connection through the synchronous toothed belt (29), the caterpillar band (26) is in transmission connection with the driving wheel (24) and a plurality of driven wheels (25).

3. The balance wheelchair as claimed in claim 2, wherein the steering mechanism (3) controls one of the crawler traveling mechanisms (2) to steer, the steering mechanism (3) comprises a mounting plate (31), a steering motor (32), a pinion (33), a gearwheel (34) and a vertical shaft (35), a mounting groove (36) is formed in the bottom of the lower support frame (11), the vertical shaft (35) is rotatably mounted in the mounting groove (36), the mounting plate (31) is mounted at the lower end of the lower support frame (11), the steering motor (32) is mounted on the mounting plate (31), the pinion (33) is mounted on an output shaft of the steering motor (32), the gearwheel (34) meshed with the pinion (33) is mounted at the lower end of the vertical shaft (35), and the lower end of the vertical shaft (35) is fixedly connected with the U-shaped bracket (21) of the crawler traveling mechanism (2), the U-shaped supports (21) of the other two crawler traveling mechanisms (2) are arranged at the bottom of the lower support frame (11).

4. The balance wheelchair as claimed in any one of claims 1 to 4, wherein two of the supporting columns (12) are respectively provided with a positioning mechanism (7), each positioning mechanism (7) comprises a second hinge shaft (71), a positioning sleeve (72), an adjusting screw (73), a sliding spring (75) seat (74), a spring (75) and a steel ball (76), the supporting column (12) is provided with two symmetrically distributed clamping grooves (121), the second hinge shaft (71) is rotatably arranged in the supporting column (12), two ends of the second hinge shaft (71) extend out of the supporting column (12) and are fixed with the positioning sleeve (72), a sliding groove perpendicular to the supporting column (12) is formed in the positioning sleeve (72), the sliding groove is internally provided with the sliding spring (75) seat (74) in a sliding manner, and one end of the sliding spring (75) seat (74) facing the supporting column (12) is fixed with the spring (75), the steel ball (76) with draw-in groove (121) joint is installed to the spring (75) other end, threaded connection has adjusting screw (73) on position sleeve (72), adjusting screw (73) one end screw in the spout in with slide spring (75) seat (74) butt, lower connecting rod (13) are fixed on position sleeve (72).

5. a balance wheelchair according to claim 1, characterised in that the U-shaped plate (14) is formed by a horizontal web (41) and side uprights (142) fixed to the two sides of the horizontal web (41).

6. a balance wheelchair according to claim 1, characterised in that the seat (5) comprises a seat plate (52), armrests (53), a backrest (54), a apron (55) and footrests (51), the seat plate (52) being fixed to the connecting plate (41), the backrest (54) being fixed to one side of the seat plate (52), the apron (55) being fixed to the other side of the seat plate (52), the armrests (53) being fixed to the backrest (54) and the seat plate (52), the footrests (51) being fixed to the lower end of the apron (55).

7. A balance wheelchair in accordance with claim 1, characterised in that the self-locking rotary drive (9) comprises an electric motor (93) and a worm gear reducer (94), the electric motor (93) being in driving connection with the worm gear reducer (94).