Track Robot

Abstract

The present invention discloses a rail robot, comprising a frame arranged on a rail, a rail measuring device and a driving device arranged on the frame, and a limiting device arranged on the frame, wherein the driving device comprises a front driving assembly and a rear driving assembly arranged on the frame, and the front driving assembly comprises a front driving motor arranged on the frame, a front roller connected to the front driving motor via a first transmission member, and a guide structure connected to the front roller. The rail robot of the present invention solves the shortcomings of low accuracy in manual measurement in the prior art, and saves labor, making rail measurement more convenient, time-saving and labor-saving. The buffer structure of the present invention reduces the probability that the friction wheel will deviate from the rail surface and idle or slip when encountering potholes, etc.; the limiting device and protective device of the present invention enable the rail robot to move smoothly on the rail, reducing the risk of the rail robot deviating from the rail.

Description

Technical Field

[0001] The invention relates to the technical field of mobile robots, and in particular to a track robot. Background Art

[0002] Many fruit trees and other agricultural and forestry crops are planted in hills, slopes and other places where the terrain is not flat. These places are difficult to build, or the construction is not economical and reasonable. It is very inconvenient to transport goods up and down and back and forth. Therefore, people have developed rail transportation devices suitable for mountain transportation.

[0003] Mountain rail transport devices are increasingly being used, as they can replace manual labor to transport picked fruits, tea and other products down the mountain. However, the specific parameters of mountain rails, such as length and track conditions, still need to be measured and recorded manually, which takes a lot of time and effort, and the accuracy of the parameters measured manually is not high. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a track robot.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] A track robot comprises a frame arranged on a track, a track measuring device and a driving device arranged on the frame, and a limiting device arranged on the frame. The driving device comprises a front driving assembly and a rear driving assembly arranged on the frame. The front driving assembly comprises a front driving motor arranged on the frame, a front roller connected to the front driving motor through a first transmission member, and a guide structure connected to the front roller. In the above technical scheme, the driving device is used to drive the movement of the track robot of the present invention; the track measuring device is used to measure track parameters such as track length, which solves the shortcomings of low accuracy in manual measurement in the prior art, saves labor, and makes track measurement more convenient, time-saving and labor-saving; the limiting device enables the track robot to move smoothly on the track, reducing the risk of the track robot deviating from the track. The front driving motor drives the front roller through the first transmission member, thereby driving the track robot to move on the track, and the front roller realizes the steering function through the guide structure.

[0007] Preferably, the first transmission member includes a first belt transmission structure connected to the front drive motor, the first belt transmission structure includes a first synchronous pulley connected to the front drive motor and a second synchronous pulley connected to the front roller, and the first synchronous pulley and the second synchronous pulley are connected via a front synchronous belt. In the above technical solution, the motor shaft of the front drive motor is connected to the first synchronous pulley, the front drive motor drives the first synchronous pulley to rotate via the motor shaft, the first synchronous pulley drives the second synchronous pulley to rotate via the front synchronous belt, and the second synchronous pulley drives the front roller to roll, so that the roller drives the track robot to move on the track.

[0008] Preferably, the front drive motor is mounted on the frame through the front connection frame, the front roller is mounted on the bottom of the frame through the front wheel frame, and the front wheel frame is provided with a front transmission shaft for connecting the second synchronous pulley and the front roller. In the above technical solution, the front wheel frame is a U-shaped structure, the front roller is arranged between the two side walls of the U-shaped front wheel frame, the front transmission shaft passes through the front wheel frame and is rotatably connected to the front wheel frame through a bearing, and the front transmission shaft also passes through the center of the front roller and is fixedly connected to the front roller, so that the second synchronous pulley drives the front roller to rotate through the front transmission shaft.

[0009] Preferably, the guide structure includes a bearing seat fixed on the frame, a rotating shaft rotatably connected to the bearing seat, and the rotating shaft is connected to the front wheel frame. In the above technical solution, the rotating shaft realizes the steering of the front wheel frame, so that the front roller cooperates with the limit device to drive the rail robot of the present invention to turn.

[0010] Preferably, the rear drive assembly includes a rear drive motor arranged on the frame, and a rear roller connected to the rear drive motor through a second transmission member; the second transmission member includes a second belt drive structure connected to the rear drive motor, the second belt drive structure includes a third synchronous pulley connected to the rear drive motor, and a fourth synchronous pulley connected to the rear roller, and the third synchronous pulley and the fourth synchronous pulley are connected through a rear synchronous belt; the rear drive motor is mounted on the frame through a rear connection, and the rear roller is mounted on the bottom of the frame through a rear wheel, and a rear transmission shaft for connecting the fourth synchronous pulley and the rear roller is provided on the rear wheel frame. In the above technical scheme, the motor shaft of the rear drive motor is connected to the third synchronous pulley, the rear drive motor drives the third synchronous pulley to rotate through the motor shaft, the third synchronous pulley drives the fourth synchronous pulley to rotate through the rear synchronous belt, and the fourth synchronous pulley rotates after the rear roller moves, so that the rear roller cooperates with the front roller to further drive the track robot of the present invention to move. The rear wheel frame is also a U-shaped structure, the rear roller is arranged between the two side walls of the U-shaped rear wheel frame, the rear transmission shaft passes through the rear wheel frame and is rotatably connected to the rear wheel frame through a bearing, and the rear transmission shaft also passes through the center of the rear roller and is fixedly connected to the rear roller, so that the fourth synchronous pulley drives the rear roller to rotate through the rear transmission shaft. The rear drive assembly serves as a follow-up rolling assembly, so there is no need to set a guide structure, saving costs and simplifying the structure.

[0011] Preferably, the track measuring device includes a bracket, an encoder arranged on the bracket, a friction wheel connected to the encoder, and a buffer structure arranged on the bracket, wherein the buffer structure includes a bearing seat arranged on the bracket, a buffer shaft slidably connected to the bearing seat, and a spring sleeved on the buffer shaft, wherein one end of the buffer shaft is fixedly connected to the frame, and the other end of the buffer shaft is inserted into the bearing seat and slidably connected to the bearing seat, one end of the spring is fixedly sleeved on the buffer shaft, and the other end of the spring is against the bearing seat. In the above technical scheme, the friction wheel fits the track, and the friction wheel rolls on the track. The track length can be accurately calculated by calculating the number of rolling circles of the friction wheel through the encoder, thereby solving the shortcomings of low accuracy in manual measurement in the prior art, saving labor, and making track measurement more convenient, time-saving and labor-saving. The buffer structure promotes the fit of the friction wheel to the track. When the friction wheel encounters potholes, the pressing force of the spring makes the friction wheel fit the track as much as possible, reducing the probability of the friction wheel detaching from the track surface and idling or slipping when encountering potholes, further increasing the accuracy of the track robot of the present invention in measuring the track length. Two buffer structures are arranged on the bracket, so that the track robot has a more stable buffer effect.

[0012] Preferably, the limiting device includes a left limiting assembly and a right limiting assembly respectively arranged on both sides of the frame through a left supporting plate and a right supporting plate. In the above technical scheme, the left limiting assembly cooperates with the right limiting assembly so that the rail robot of the present invention moves stably along the rail, and the left supporting plate and the right supporting plate are respectively arranged on both sides of the lower surface of the frame.

[0013] Preferably, the left support plate and the right support plate are both provided with an upper support seat and a lower support seat, and the left limit assembly and the right limit assembly both include a guide shaft, a guide wheel, and a guide wheel support. The guide shaft passes through the upper support seat and the lower support seat in turn and is installed on the upper support seat and the lower support seat. The guide wheel support is rotatably connected with the guide shaft, and the guide wheel is arranged on the guide wheel support. In the above technical scheme, the guide wheel is located on the side of the track. When the track robot deviates to one side, the guide wheel on this side is stressed and limits the track robot, so that the track robot moves stably on the track, reducing the probability of the track robot leaving the track. The upper support seat cooperates with the lower support seat to make the guide shaft more stable, and the guide wheel support can be rotatably connected with the guide shaft through a bearing, so that the guide wheel is suitable for tracks with curvature. Preferably, there are two left limit assemblies on the left side of the frame, and two right limit assemblies on the right side of the frame. The two left limit assemblies and the two right limit assemblies further increase the stability of the track robot moving on the track.

[0014] Preferably, the track robot of the present invention further includes a protective device arranged on the frame, the protective device includes a protective rod connected to the guide shaft, the protective rod includes a first rod connected to the guide shaft, a second rod vertically connected to the first rod, and a third rod vertically connected to the second rod, the first rod, the second rod, and the third rod form a U-shape, and the track is located between the first rod and the third rod. In the above technical scheme, the protective device is arranged at the lower end of the frame, and the track is also located between the frame and the second rod. The protective device prevents the track robot from deviating from the track when encountering serious external interference, so that even if the track robot deviates from the track, it will not fall from the track, reducing the risk of the track robot falling and being damaged. Preferably, the number of protective devices is 2, and the first rods of the two protective devices are connected by a connecting rod.

[0015] Preferably, the front roller and the rear roller are magnetic wheels; the frame is also provided with a camera and a temperature and humidity sensor; and a magnet is also provided under the frame. In the above technical scheme, the track is generally made of iron or other metals. The magnetic wheel cooperates with the limit device to make the overall structure of the track robot light and simple, so that the track robot can run stably and at high speed on the track surface, and also reduces the probability of the track robot falling back due to insufficient power when climbing, which is convenient for the track robot to climb. The camera can collect the track conditions and the surrounding environment in real time, which is convenient for the staff to monitor the track conditions and the surrounding environment. The temperature and humidity sensor can collect the surrounding temperature and humidity information in real time, which further facilitates the staff to know the temperature and humidity of the upper environment without entering the mountain. If the staff wants to enter the mountain environment, it is convenient for the staff to prepare in advance. The installation and disassembly of the magnet can be facilitated by opening an installation slot under the frame. The magnet is located above the track and generates magnetic force with the track, which further makes the track robot fit with the track, reducing the probability of the track robot falling back due to insufficient power when climbing, which is convenient for the track robot to climb. The magnet can be located directly above the track, or multiple magnets can be evenly located above the track side, so that the magnetic force generated above the two sides of the track is also perpendicular to the track surface.

[0016] The present invention has the following beneficial effects:

[0017] 1. The track robot of the present invention solves the shortcomings of low accuracy in manual measurement in the prior art, saves labor, and makes track measurement more convenient, time-saving and labor-saving;

[0018] 2. The buffer structure reduces the probability of the friction wheel detaching from the track surface and idling or slipping when encountering potholes, etc., further increasing the accuracy of the track robot of the present invention in measuring the track length;

[0019] 3. The limit device and protective device enable the track robot to move smoothly on the track, reducing the risk of the track robot deviating from the track. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the track robot of the present invention;

[0021] Figure 2 is a schematic structural diagram of a front drive assembly of the present invention;

[0022] Figure 3 is a schematic structural diagram of a rear drive assembly of the present invention;

[0023] Figure 4 It is a schematic structural diagram of the track measurement device of the present invention;

[0024] Figure 5 Schematic diagram of the structure of the limiting device of the present invention

[0025] Figure 6 It is a schematic structural diagram of the protection device of the present invention.

[0026] In the figure: 1, track, 2, frame, 3, track measuring device, 31, bracket, 32, encoder, 33, friction wheel, 34, bearing seat, 35, buffer shaft, 36, spring, 4, driving device, 41, front driving assembly, 411, front driving motor, 412, front roller, 413, first synchronous pulley, 414, second synchronous pulley, 415, front synchronous belt, 416, front connecting frame, 417, front wheel frame, 418, front transmission shaft, 419, second bearing seat, 4110, rotating shaft, 42, rear driving assembly Parts, 421, rear drive motor, 422, rear roller, 423, third synchronous pulley, 424, fourth synchronous pulley, 425, rear synchronous belt, 426, rear connecting frame, 427, rear wheel frame, 428, rear transmission shaft, 5, limiting device, 51, left support plate, 52, right support plate, 53, upper support seat, 54, lower support seat, 55, guide shaft, 56, guide wheel support, 57, guide wheel, 6, protection device, 61, first rod, 62, second rod, 63, third rod, 7, camera, 8, temperature and humidity sensor. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and implementation modes.

[0028] like Figure 1-6 As shown, the track robot of this embodiment includes a frame 2 arranged on the track 1, a track measuring device 3 and a driving device 4 arranged on the frame 2, and a limiting device 5 arranged on the frame 2. The driving device 4 includes a front driving component 41 and a rear driving component 42 arranged on the frame 2. The front driving component 41 includes a front driving motor 411 arranged on the frame 2, a front roller 412 connected to the front driving motor 411 through a first transmission member, and a guide structure connected to the front roller 412.

[0029] In this embodiment, the first transmission member includes a first belt drive structure connected to the front drive motor 411, the first belt drive structure includes a first synchronous pulley 413 connected to the front drive motor 411, and a second synchronous pulley 414 connected to the front roller 412, and the first synchronous pulley 413 and the second synchronous pulley 414 are connected through a front synchronous belt 415.

[0030] In this embodiment, the front drive motor 411 is arranged on the frame 2 through the front connecting frame 416, and the front roller 412 is arranged at the bottom of the frame 2 through the front wheel frame 417. The front wheel frame 417 is provided with a front transmission shaft 418 for connecting the second synchronous pulley 414 and the front roller 412.

[0031] In this embodiment, the guide structure includes a first bearing seat 419 fixed on the frame 2 and a rotating shaft 4110 rotatably connected to the first bearing seat 419 , and the rotating shaft 4110 is connected to the front wheel frame 417 .

[0032] In this embodiment, the rear drive assembly 42 includes a rear drive motor 421 arranged on the frame 2, and a rear roller 422 connected to the rear drive motor 421 through a second transmission member; the second transmission member includes a second belt drive structure connected to the rear drive motor 421, and the second belt drive structure includes a third synchronous pulley 423 connected to the rear drive motor 421, and a fourth synchronous pulley 424 connected to the rear roller 422, and the third synchronous pulley 423 is connected to the fourth synchronous pulley 424 through a rear synchronous belt 425; the rear drive motor 421 is arranged on the frame 2 through a rear connecting frame 426, and the rear roller 422 is arranged at the bottom of the frame 2 through a rear wheel frame 427, and the rear wheel frame 427 is provided with a rear transmission shaft 428 for connecting the fourth synchronous pulley 424 and the rear roller 422.

[0033] In this embodiment, the track measuring device 3 includes a bracket 31, an encoder 32 arranged on the bracket 31, a friction wheel 33 connected to the encoder 32, and a buffer structure arranged on the bracket 31. The buffer structure includes a second bearing seat 34 arranged on the bracket 31, a buffer shaft 35 slidably connected to the second bearing seat 34, and a spring 36 sleeved on the buffer shaft 35. One end of the buffer shaft 35 is fixedly connected to the frame 2, and the other end of the buffer shaft 35 is inserted into the second bearing seat 34 and slidably connected to the second bearing seat 34. One end of the spring 36 is fixedly sleeved on the buffer shaft 35, and the other end of the spring 36 is against the second bearing seat 34.

[0034] In this embodiment, the limiting device 5 includes a left limiting assembly and a right limiting assembly which are respectively arranged on both sides of the frame 2 through a left supporting plate 51 and a right supporting plate 52 .

[0035] In this embodiment, the left support plate 51 and the right support plate 52 are both provided with an upper support seat 53 and a lower support seat 54, and the left limit assembly and the right limit assembly both include a guide shaft 55, a guide wheel 57, and a guide wheel support 56. The guide shaft 55 passes through the upper support seat 53 and the lower support seat 54 in sequence and is installed on the upper support seat 53 and the lower support seat 54. The guide wheel support 56 is rotatably connected to the guide shaft 55, and the guide wheel 57 is arranged on the guide wheel support 56.

[0036] In this embodiment, the track robot of this embodiment also includes a protective device 6 arranged on the frame 2, the protective device 6 includes a protective rod connected to the guide shaft 55, the protective rod includes a first rod 61 connected to the guide shaft 55, a second rod 62 vertically connected to the first rod 61, and a third rod 63 vertically connected to the second rod 62. The first rod 61, the second rod 62, and the third rod 63 form a U-shape, and the track 1 is located between the first rod 61 and the third rod 63.

[0037] In this embodiment, the front roller 412 and the rear roller 422 are both magnetic wheels; a camera 7 and a temperature and humidity sensor 8 are also provided on the frame 2; and a magnet is also provided under the frame 2.

[0038] In the description of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if the terms "first", "second", "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Simple replacement without changing the creative content of the present invention is considered to be the same creation. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. Track robot, characterized in that: The invention comprises a vehicle frame (2) arranged on a track (1), a track measuring device (3) and a driving device (4) arranged on the vehicle frame (2), and a limiting device (5) arranged on the vehicle frame (2); the driving device (4) comprises a front driving assembly (41) and a rear driving assembly (42) arranged on the vehicle frame (2); the front driving assembly (41) comprises a front driving motor (411) arranged on the vehicle frame (2), a front roller (412) connected to the front driving motor (411) via a first transmission member, and a guide structure connected to the front roller (412); The track measuring device (3) comprises a bracket (31), an encoder (32) arranged on the bracket (31), a friction wheel (33) connected to the encoder (32), and a buffer structure arranged on the bracket (31), wherein the buffer structure comprises a second bearing seat (34) arranged on the bracket (31), a buffer shaft (35) slidably connected to the second bearing seat (34), and a spring (36) sleeved on the buffer shaft (35), wherein one end of the buffer shaft (35) is fixedly connected to the vehicle frame (2), and the other end of the buffer shaft (35) is inserted into the second bearing seat (34) and slidably connected to the second bearing seat (34), and the spring (36) is sleeved on the buffer shaft (35). The end of the spring (36) is fixedly sleeved on the buffer shaft (35), the other end of the spring (36) is against the second bearing seat (34), the friction wheel (33) is in contact with the track (1), the friction wheel (33) rolls on the track (1), the buffer structure promotes the friction wheel (33) to be in contact with the track (1), when the friction wheel (33) encounters a pothole, the pressing force of the spring makes the friction wheel (33) in contact with the track (1), reducing the probability of the friction wheel (33) detaching from the surface of the track (1) and idling or slipping when encountering a pothole. Two buffer structures are provided on the bracket (31), so that the track robot has a more stable buffer effect; The limiting device (5) comprises a left limiting assembly and a right limiting assembly respectively arranged on both sides of the frame (2) through a left supporting plate (51) and a right supporting plate (52); the left limiting assembly cooperates with the right limiting assembly to enable the track robot to move stably along the track; the left supporting plate and the right supporting plate are respectively arranged on both sides of the lower surface of the frame; The left support plate (51) and the right support plate (52) are both provided with an upper support seat (53) and a lower support seat (54); the left limit assembly and the right limit assembly both include a guide shaft (55), a guide wheel (57), and a guide wheel support seat (56); the guide shaft (55) passes through the upper support seat (53) and the lower support seat (54) in sequence and is installed on the upper support seat (53) and the lower support seat (54); the guide wheel support seat (56) is rotatably connected to the guide shaft (55); the guide wheel (57) is arranged on the guide wheel support seat (56); the guide wheel (57) is located on the side of the track (1); when the track robot deviates to one side, the guide wheel (57) on that side The force is applied to the track robot and the position is limited, so that the track robot can move stably on the track (1), and the probability of the track robot leaving the track (1) is reduced. The upper support seat (53) cooperates with the lower support seat (54) to make the guide shaft (55) more stable. The guide wheel (57) support is rotatably connected to the guide shaft (55) through a bearing, so that the guide wheel (57) is suitable for a track (1) with a curvature. There are two left-side limit assemblies on the left side of the frame (2), and there are two right-side limit assemblies on the right side of the frame (2). The two left-side limit assemblies and the two right-side limit assemblies further increase the stability of the track robot moving on the track (1); The vehicle frame (2) further comprises a protection device (6) arranged on the vehicle frame (2), the protection device (6) comprising a protection rod connected to the guide shaft (55), the protection rod comprising a first rod (61) connected to the guide shaft (55), a second rod (62) vertically connected to the first rod (61), and a third rod (63) vertically connected to the second rod (62), the first rod (61), the second rod (62), and the third rod (63) forming a U-shape, the track (1) being located between the first rod (61) and the third rod (63), the protection device (6) being arranged at the lower end of the vehicle frame (2), the track (1) being also located between the vehicle frame (2) and the second rod (62), the protection device (6) preventing the track robot from deviating from the track when encountering serious external interference, so that the track robot does not fall from the track even if it deviates from the track (1), thereby reducing the risk of the track robot falling and being damaged, the number of the protection devices (6) is two, and the first rods (61) of the two protection devices (6) are connected by a connecting rod; The front roller (412) and the rear roller (422) are both magnetic wheels; a camera (7) and a temperature and humidity sensor (8) are also provided on the vehicle frame (2); and a magnet is also provided below the vehicle frame (2); The magnetic wheel cooperates with the limit device to enable the track (1) robot to run on the track (1) surface, reducing the probability of the track (1) robot falling back due to insufficient power when climbing a slope, and facilitating the track (1) robot to climb a slope; the camera (7) collects the track (1) road conditions and the surrounding environment in real time, facilitating the staff to monitor the track (1) road conditions and the surrounding environment; the temperature and humidity sensor (8) collects the surrounding temperature and humidity information in real time, and facilitates the installation and removal of the magnet by providing an installation slot under the frame (2); the magnet is located above the track (1) and generates magnetic force with the track (1), further allowing the track (1) robot to fit with the track (1), reducing the probability of the track (1) robot falling back due to insufficient power when climbing a slope, and facilitating the track (1) robot to climb a slope; the plurality of magnets are evenly located above the side of the track (1), so that the magnetic force generated above the two sides of the track (1) is also perpendicular to the track (1) surface.

2. The rail robot according to claim 1, characterized in that: The first transmission member comprises a first belt transmission structure connected to the front drive motor (411), the first belt transmission structure comprises a first synchronous pulley (413) connected to the front drive motor (411), and a second synchronous pulley (414) connected to the front roller (412), and the first synchronous pulley (413) and the second synchronous pulley (414) are connected via a front synchronous belt (415).

3. The rail robot according to claim 2, characterized in that: The front drive motor (411) is arranged on the vehicle frame (2) via a front connecting frame (416), the front roller (412) is arranged on the bottom of the vehicle frame (2) via a front wheel frame (417), and the front wheel frame (417) is provided with a front transmission shaft (418) for connecting the second synchronous pulley (414) and the front roller (412).

4. The rail robot according to claim 3, characterized in that: The guide structure comprises a first bearing seat (419) fixedly arranged on the vehicle frame (2), a rotating shaft (4110) rotatably connected to the first bearing seat (419), and the rotating shaft (4110) is connected to the front wheel frame (417).

5. The track robot according to claim 1, 2, 3 or 4, characterized in that: The rear drive assembly (42) comprises a rear drive motor (421) arranged on the vehicle frame (2), and a rear roller (422) connected to the rear drive motor (421) via a second transmission member; the second transmission member comprises a second belt transmission structure connected to the rear drive motor (421), the second belt transmission structure comprises a third synchronous pulley (423) connected to the rear drive motor (421), and a fourth synchronous pulley (424) connected to the rear roller (422), the third synchronous pulley (423) and the fourth synchronous pulley (424) being connected via a rear synchronous belt (425); the rear drive motor (421) is arranged on the vehicle frame (2) via a rear connecting frame (426), the rear roller (422) is arranged at the bottom of the vehicle frame (2) via a rear wheel frame (427), and the rear wheel frame (427) is provided with a rear transmission shaft (428) for connecting the fourth synchronous pulley (424) and the rear roller (422).

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