CN215454060U

CN215454060U - Tree climbing type vibration harvesting machine

Info

Publication number: CN215454060U
Application number: CN202120379409.4U
Authority: CN
Inventors: 金晶; 许林云; 韩元顺; 潘广昊
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2021-02-20
Filing date: 2021-02-20
Publication date: 2022-01-11
Anticipated expiration: 2031-02-20

Abstract

The utility model relates to a tree-climbing type vibration harvester, wherein a whole machine mechanism comprises a grasping mechanism, a traveling mechanism, a vibration exciting traveling mechanism and a power mechanism. The grasping mechanism mainly comprises a left clamping ring, a right clamping ring, a left clamping wheel and a right clamping wheel. The running mechanism mainly comprises a driving wheel, a driven wheel, a motor, a reduction gearbox and a vehicle body. The vibration excitation mechanism is a working main part of the whole tree climbing type fruit tree vibration harvester and mainly comprises a motor, a reduction gearbox, a diaphragm type coupler, a helical gear and an eccentric block. The power mechanism selects the motor as a power source of the tree climbing robot. And a multi-stage reduction gearbox is used for converting the polarization mechanism and the travelling mechanism. The vibration energy transmission maximization can be realized to this hair to less exciting force obtains great benefit of gathering, avoids causing the damage to the fruit tree simultaneously.

Description

Tree climbing type vibration harvesting machine

Technical Field

The utility model relates to the field of vibration harvesting, in particular to a tree climbing type vibration harvester, which achieves the purpose of achieving higher recovery ratio with smaller exciting force.

Background

China is a large fruit producing country, the yield of various fruits is kept above one hundred million tons every year, and the planting area of forest fruits is increased day by day. The fruit cultivation area in China in 2005 was 10035.2 kilo hectares, which increased 2.73% compared with 9768.6 kilo hectares in 2004. The planting structure slowly tends to be reasonable, the planting proportion of the three fruits of pear, apple and orange is obviously reduced, and the planting proportion of the small mixed fruits is greatly improved. Correspondingly, the planting area of tall trees such as trees and fruits in China is greatly increased, the planting area of some tall trees such as gingkoes is increased by 2.7% compared with that of the gingkoes in the past year, tall trees such as oak trees are distributed from south to north in China, and particularly the planting area of the tall trees in the Yunnan reaches 1.5 hundred million square meters. Meanwhile, many fruit trees still have high growth due to poor pruning technology development, vigorous apical dominance.

For the tall and big fruit trees, the growth is vigorous, the growth of the main trunk is obviously independent, the traditional large forestry picking machine is not suitable to be used, the trunk and the branches are easy to be damaged, and the collection rate is low; and the small forestry harvesting machine often has insufficient power and small exciting force, and cannot achieve good harvesting effect, so that the manual harvesting or mechanical auxiliary harvesting mode is often used for harvesting the forest fruits at present, the efficiency is low, and the harvesting purity is poor.

In order to achieve a better picking effect and achieve the purpose of achieving a larger recovery ratio with a smaller exciting force, the obvious independent characteristics of the trunk of the tree are fully utilized, fruit picking is achieved by vibrating the top end of the tall tree, and it is necessary to research a tree climbing type vibration picking machine to change the existing picking mode of tall trees.

Disclosure of Invention

The utility model aims to provide a tree-climbing type vibration harvester aiming at the defects of the prior art. The utility model mainly aims to combine the characteristics of a tree climbing type robot and a vibration harvester, and discloses a brand-new tree climbing type fruit tree vibration harvester which is used for solving the problems that trees with top advantages are difficult to mechanically shake and harvest and the like in the decentralized planting of woodland orchards in China, so that the vibration energy transfer maximization is realized, the large harvesting benefit is obtained with small exciting force, and the damage to fruit trees is avoided.

The machine is small and exquisite and sensitive, can achieve the purpose of achieving a large recovery ratio with a small exciting force, fully utilizes the obvious independent characteristic of the trunk of the tree, and achieves fruit harvesting through vibrating the top end of the tall tree.

In order to achieve the purpose, the technical scheme provided by the utility model is as follows:

a tree-climbing type vibration harvester comprises a whole machine mechanism, a grasping mechanism, a traveling mechanism, a vibration exciting traveling mechanism and a power mechanism.

The grasping mechanism comprises a left clamping ring, a right clamping ring, a left clamping wheel and a right clamping wheel, the left clamping ring and the left clamping wheel are respectively controlled by an upper electric telescopic rod and a lower electric telescopic rod, and the motor drives the upper electric telescopic rod to stretch and contract so as to firmly grasp trees. The joint position of the grasping mechanism is fixed by pin connection, and the friction force borne by the grasping mechanism is reduced to ensure that the rotation is not restrained. And finally, connecting and fixing the left clamping ring and the left clamping wheel on the upper fixing plate and the lower fixing plate in a pin connection mode, wherein in order to ensure that the upper fixing plate and the lower fixing plate can fix the clamping device, a connecting interface with a certain length and a certain angle is required to extend out of the fixing plate.

The left clamping ring and the right clamping ring in the grasping mechanism are used for firstly and secondly grasping the trunk and encircling trees with different diameters. The external pin design is adopted on the outer side of the clamping ring, so that the electric rod can control the left clamping ring and the right clamping ring to open and close.

The plastic gaskets are additionally arranged on the inner sides of the left clamping ring and the right clamping ring in order to increase the friction force between the left clamping ring and the tree, and the friction force between the left clamping ring and the tree can be increased through the plastic gaskets, so that the phenomenon of falling back after clamping can be effectively prevented.

The clamping radius of the left clamping ring and the clamping radius of the right clamping ring of the grasping mechanism are adjustable after the assembly is completed, the final clamping radius of the clamping ring can be controlled by controlling the extension and retraction of the upper electric telescopic rod, and the tree can be attached to the clamping ring when clamped, so that the purposes of holding tightly and loosening are achieved.

The left clamping wheel and the right clamping wheel in the grasping mechanism are used for assisting climbing and assisting in clamping trees. The clamping wheel consists of a lower electric telescopic rod, a fixed rod and wheels. Wherein, being connected through the axletree between dead lever and the wheel, the axletree passes through the screw with the dead lever to be connected, and the wheel passes through the fixed pin with the axletree to be connected. The fixed rod is hollow, and two pin holes are reserved and are respectively connected with the fixed frame and the electric telescopic rod on the lower portion of the fixed plate through revolute pairs. The lower electric telescopic rod is connected with the fixing frame on the upper part of the lower fixing plate 7 through a pin, so that the purposes of stretching and fixing are achieved.

The grasping mechanism adopts an electric upper electric telescopic rod and an electric lower electric telescopic rod as power sources of the grasping mechanism. Compared with a hydraulic type and pneumatic type, the upper electric telescopic rod and the lower electric telescopic rod have the advantages of fast command execution, small size, portability, flexibility and convenience in realizing clamping and loosening functions.

The running mechanism mainly comprises a driving wheel, a driven wheel, a motor, a reduction gearbox and a vehicle body. The motor and the motor adopted by the vibration excitation mechanism are the same motor, and the same motor supplies energy to the vibration excitation mechanism and the walking mechanism. The body only serves to secure and support the components. The rotating speed generated by the motor is reduced by the gear in the reduction box and then transmitted to the driving wheel shaft, and the driving wheel shaft provides power for the driving wheel to drive the driving wheel to rotate. Thereby the drive wheel is rotatory and scrambles the promotion height on trees trunk, drives simultaneously and rotates from driving wheel and left centre gripping wheel and right centre gripping wheel together to reach the purpose of climbing trees.

The walking mechanism is designed to be the same in size with the driving wheel and the driven wheel in order to ensure the overall balance of the vehicle body during climbing. When the driving wheel and the driven wheel are designed, the tires of the driving wheel and the driven wheel are designed to be concave so as to better fit the radian of the tree. The tire is made of rubber, so that the friction force between the tire and the trunk can be increased to a certain extent, and the climbing process is smoother.

The vibration excitation mechanism is a working main part of the whole tree climbing type fruit tree vibration harvester and mainly comprises a motor, a reduction gearbox, a diaphragm type coupler, a helical gear and an eccentric block. The motor is connected with a belt wheel shaft in the reduction gearbox through a diaphragm type coupler, the belt wheel shaft is connected with a belt wheel to reduce the rotating speed provided by the motor and then transmits the rotating speed to the eccentric block input shaft through the diaphragm type coupler, and the transmission direction of power is modified through the helical gear, so that the eccentric block shaft rotates to drive the two eccentric blocks to rotate together, and polarization is realized.

The power mechanism selects the motor as a power source of the tree climbing robot. The power mechanisms are fixed on the fixing plate through pins, a storage battery and a direct current motor are used as power sources, the multistage reduction gearbox is used for converting the polarization mechanism and the travelling mechanism, and power is provided for the two mechanisms simultaneously.

The motor speed of the power mechanism can be reduced within one-time speed reduction, and the reduction ratio is not too large due to space limitation.

This design simple structure, weight distribution is reasonable, and is easy and simple to handle, helps plucking the tall and big arbor and the forest that ordinary fruit tree shake harvester is difficult to gather.

Compared with the prior art, the research conclusion of the utility model is mainly reflected in the following aspects:

(1) the clamp ring of the technology is designed to be capable of embracing trees with different diameters. The external pin design is adopted at the outer side of the clamping ring, so that the electric rod can control the clamping ring to open and close. In order to increase the friction force between the clamping ring and the tree, the plastic washer is additionally arranged on the inner side of the clamping ring, and the friction force of the clamping ring is increased through the plastic washer, so that the phenomenon of falling back after clamping can be effectively prevented.

(2) Two wheels are laid on the vehicle body, the rear wheel is a driving wheel and is used for receiving power transmitted by the motor and converting the power into mechanical energy which overcomes the gravity to do work; the front wheel is the unpowered driven wheel, and its effect is the moment that the balanced automobile body received when the climbing for the automobile body can not take place to incline or turn on one's side when moving, stability when having improved the automobile body motion.

(3) The holistic balance of automobile body when this technique is in order to guarantee the climbing is the same for the size with drive wheel and follow driving wheel design. In order to make the wheel better cling to the trunk, the wheel is designed to have a certain radian when the wheel is designed. The tire is made of rubber, so that the friction force between the tire and the trunk can be increased to a certain extent, and the climbing process is smoother.

(4) The technology selects a design that a vehicle body carries a storage battery for climbing, the tree climbing type fruit tree vibration harvester provides energy for a motor, and the design that an eccentric block and a driving wheel are respectively controlled by using a double electromagnetic clutch is adopted, so that the tree climbing type fruit tree vibration harvester is convenient to start and stop;

this design evenly distributed the position of motor and storage battery, place motor and storage battery respectively in the both ends of automobile body for certain smoothness has during the automobile body climbing. Simultaneously, two eccentric blocks are used for completing the shaking work of the trunk, and the two eccentric blocks are arranged in the middle of the vehicle body in a front-back mode, so that the space in the vehicle is compact, and the vehicle body is more stable and reliable. This design is placed excitation mechanism inside the automobile body, and the focus can be guaranteed steadily in such design, can not appear because the eccentric block is external and the potential safety hazard that leads to when shaking the fruit tree.

Drawings

Fig. 1a is a schematic view (front view) of the vibration harvester for climbing trees of the utility model when the harvester is opened.

Fig. 1b is a schematic view (top view) of the vibration harvester for climbing fruit trees of the utility model when opened.

Fig. 2a is a schematic view (front view) of the vibrating harvester for climbing fruit trees of the present invention when closed.

Fig. 2b is a schematic view (top view) of the tree-climbing type fruit tree vibration harvester of the utility model when closed.

Fig. 3a is a grasping mechanism diagram (front view) of the tree climbing type fruit tree vibration harvester of the utility model.

Fig. 3b is a view (top view) of the grasping mechanism of the vibrating harvester for climbing fruit tree of the present invention.

Fig. 4a is a clamping range diagram (front view) of the clamping ring and the clamping wheel of the tree-climbing fruit tree vibration harvester of the utility model.

Fig. 4b is a view (top view) of the clamping range of the clamping ring and the clamping wheel of the tree-climbing fruit tree vibration harvester of the utility model.

Fig. 5 is a wheel attaching diagram of the walking mechanism of the tree-climbing fruit tree vibration harvester of the utility model.

Fig. 6 is a schematic diagram of a reduction gearbox in a walking mechanism of the tree-climbing fruit tree vibration harvester.

Description of the drawings: the device comprises a plastic washer 1, a left clamping ring 2, a right clamping ring 2-1, a right clamping wheel 11-1, an upper fixing plate 3, a pin 4, an upper electric telescopic rod 5, a vehicle body 6, a lower fixing plate 7, a lower electric telescopic rod 8, a fixing rod 9, a clamping wheel bent shaft 10, a left clamping wheel 11, a battery 12, a power mechanism fixing plate 13, a reduction gearbox 14, a driven wheel 15, a driving wheel 16, a motor 17, a diaphragm type coupler 18, a belt wheel shaft 19, a helical gear 20, an eccentric block 21 and a trunk 100.

Detailed Description

The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the utility model and not as limiting the scope of the utility model. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

As shown in the figure, the tree climbing type fruit tree vibration harvester comprises a whole machine mechanism, a grasping mechanism, a traveling mechanism, a vibration exciting traveling mechanism and a power mechanism.

The grasping mechanism comprises a left clamping ring 2, a right clamping ring 2-1, a left clamping wheel 11 and a right clamping wheel 11-1, the left clamping ring 2 and the left clamping wheel 11 are respectively controlled by an upper electric telescopic rod 5 and a lower electric telescopic rod 8, and a motor 17 drives the upper electric telescopic rod 5 to stretch and contract so as to firmly grasp the tree. The joint position of the grasping mechanism is fixed by connecting the pins 4, and the friction force borne by the grasping mechanism is reduced to ensure that the rotation is not restrained. And finally, the left clamping ring 2 and the left clamping wheel 11 are connected in a pin connection mode and fixed on the upper fixing plate 3 and the lower fixing plate 7, and in order to ensure that the upper fixing plate 3 and the lower fixing plate 7 can fix the clamping device, a connecting interface with certain length and angle is required to extend out of the fixing plate.

The left clamping ring 2 and the right clamping ring 2-1 in the grasping mechanism have the functions of firstly and secondly grasping the trunk 100 and grasping trees with different diameters. The outer side of the clamping ring adopts an external pin design, so that the electric rod can control the left clamping ring 2 and the right clamping ring 2-1 to open and close.

In order to increase the friction force between the left clamping ring 2 and the tree, the plastic washers 1 are additionally arranged on the inner sides of the left clamping ring 2 and the right clamping ring 2-1, and the friction force between the left clamping ring 2 and the right clamping ring 2-1 is increased through the plastic washers 1, so that the phenomenon of falling back after clamping can be effectively prevented.

The clamping radius of the left clamping ring 2 and the right clamping ring 2-1 of the grasping mechanism is adjustable after the assembly is completed, the final clamping radius of the clamping rings can be controlled by controlling the extension and retraction of the upper electric telescopic rod 5, and the tree can be attached to the tree when being clamped, so that the purposes of clasping and loosening are achieved.

The left clamping wheel 11 and the right clamping wheel 11-1 in the gripping mechanism are used for assisting climbing and assisting clamping of trees. The clamping wheel consists of a lower electric telescopic rod 8, a fixed rod 9 and wheels 11. The clamping wheel bent shaft 10 and the clamping wheel 11 are fixed through pin connection. Wherein, be connected through the axletree between dead lever 9 and the wheel 11, the axletree passes through the screw with the dead lever to be connected, and the wheel is connected through the fixed pin with the axletree. The fixed rod is hollow, and two pin holes are reserved and are respectively connected with the fixed frame and the electric telescopic rod on the lower portion of the fixed plate through revolute pairs. The lower electric telescopic rod 8 is connected with the fixing frame on the upper part of the lower fixing plate 7 through a pin, so that the purposes of stretching and fixing are achieved.

The grasping mechanism adopts an electric upper electric telescopic rod 5 and an electric lower electric telescopic rod 8 as power sources of the grasping mechanism. Go up electric telescopic handle 5 and electric telescopic handle 8 down compare fluid pressure type and pneumatic execution command fast, small, light nimble, be convenient for realize centre gripping and lax function.

The travelling mechanism mainly comprises a driving wheel 16, a driven wheel 15, a motor 17, a reduction box 14 and a vehicle body 6. The motor 17 and the motor adopted by the excitation mechanism are the same motor, and the same motor supplies energy to the excitation mechanism and the traveling mechanism. The vehicle body 6 only serves to fix and support the respective components. The rotational speed generated by the motor is reduced by the gear in the reduction box 14 and then transmitted to the driving wheel shaft, and the driving wheel shaft provides power for the driving wheel 16 to drive the driving wheel 16 to rotate. The driving wheel 16 rotates and climbs on the trunk of the tree to lift the height, and simultaneously drives the driven wheel 15 and the left clamping wheel 11 and the right clamping wheel 11-1 to rotate together, so that the purpose of climbing the tree is achieved.

In order to ensure the balance of the whole body when climbing, the walking mechanism designs the driving wheel 16 and the driven wheel 15 to be the same in size. In designing the drive wheel 16 and the driven wheel 15, the tires of the drive wheel 16 and the driven wheel 15 are designed to be concave so as to better conform to the arc of a tree. The tire is made of rubber, so that the friction force between the tire and the trunk can be increased to a certain extent, and the climbing process is smoother.

The vibration excitation mechanism is a working main part of the whole tree climbing type fruit tree vibration harvester and mainly comprises a storage battery 12, a motor 17, a reduction box 14, a diaphragm type coupling 18, a helical gear 20 and an eccentric block 21. The motor 17 is connected with a belt wheel shaft 19 in the reduction gearbox 14 through a diaphragm type coupling 18, the belt wheel shaft 19 is connected with a belt wheel to reduce the rotating speed provided by the motor 17 and then transmit the reduced rotating speed to the eccentric block input shaft through the diaphragm type coupling 18, and the transmission direction of the power is modified through the bevel gear 20, so that the eccentric block shafts rotate to drive the two eccentric blocks 21 to rotate together, and polarization is realized.

The power mechanism selects the motor 17 as a power source of the tree climbing robot. The power mechanisms are fixed on the fixing plate 13 through pins, a storage battery 12 and a direct current motor 17 are used as power sources, the multistage reduction gearbox 14 is used for converting the polarization mechanism and the travelling mechanism, and power is provided for the two mechanisms at the same time. The battery 12, the motor and the reduction box form a power mechanism. The power mechanism fixing plate 13 fixes the power mechanism.

The motor speed of the power mechanism can be reduced within one-time speed reduction, and the reduction ratio is not too large due to space limitation. The working process and the working principle of the utility model are as follows: the electric telescopic rods 5 of the clamping rings 2 and 2-1 are initially in a contracted state, and the electric telescopic rods 8 of the clamping wheels 11 and 11-1 are initially in a stretched state. The working personnel sleeve the clamping wheel 11 and the clamping ring 11-1 on the trunk, start the electric telescopic rods 8 of all the grasping devices, and the electric telescopic rods 8 of the clamping wheel 11 and the clamping ring 11-1 will contract, so that the tires of the clamping wheel and the

tires

15 and 16 of the walking mechanism slowly adhere to the tree and firmly hold the trunk; simultaneously, the electric telescopic rods 5 of the clamping rings 2 and 2-1 will be stretched, so that the clamping rings 2 and 2-1 slightly hold the trunk. And then the motor 17 is started, the rotating speed generated by the motor 17 is subjected to multi-stage speed reduction through the gears in the reduction gearbox 14, the clutches are combined and separated, at the moment, the rotating speed of the motor 17 is completely transmitted to the driving wheel 16 after being subjected to speed reduction, the driving wheel 16 grips the trunk and starts to rise through the friction force between the trunk and the tires, meanwhile, the driven wheel 15 is driven to rotate, and under the action of the driving wheel 16, the climbing type fruit tree vibration harvester rises to reach the designated height within the specified time. Before reaching the designated height, the ground worker should remotely control the clutch inside the reduction gearbox 14 to separate and combine the clutch, at the moment, the rotating speed of the motor 17 is completely transmitted to the eccentric block 21 of the polarization mechanism through belt wheel deceleration and bevel gear meshing, and the vehicle body will continuously rise to the designated height by means of inertia. When the tree trunk is lifted to a designated height, a worker remotely operates the electric telescopic rods 5 of the clamping rings 2 and 2-1, and the clamping rings 2 and 2-1 which originally hold the tree trunk gently clamp the tree trunk tightly and suspend the tree trunk at a designated position. At the moment, the polarizing mechanism shakes the top end of the trunk, so that the fruit obtains centrifugal force, and when the centrifugal force borne by the fruit is greater than the binding force of the fruit stem, the fruit falls off and falls into a fruit collecting device on the ground. After the picking work is finished, the worker remotely controls the clutch to enable the clutch to be combined and separated, the remote control motor 17 rotates reversely, and meanwhile, the clamping rings 2 and 2-1 are remotely operated to clamp the tree trunk with force and suspend the tree trunk at a specified position. At this moment, the polarizing mechanism shakes the top end of the trunk, so that the electric telescopic rod 5 for the fruit is obtained slightly contracts, and the electric telescopic rod returns to the state of slightly clamping the tree when the tree just begins to climb. At the moment, the motor 17 rotates reversely, the tree-climbing fruit tree vibration harvester falls back, and the tree-climbing fruit tree vibration harvester cannot fall back continuously due to the limitation of the clamping rings 2 and 2-1 when the tree-climbing fruit tree vibration harvester falls to the initial height. At this time, the worker should turn off the motor 17, operate the electric

telescopic rods

5 and 8 to enable the clamping mechanism to loosen the trunk, take down the climbing type fruit tree vibration harvester, complete one-time harvesting operation and prepare for harvesting the next tree.

The technical means disclosed in the utility model scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features.

Claims

1. The utility model provides a tree climbing formula vibration harvester which characterized in that: the harvester comprises a grasping mechanism, an excitation mechanism, a traveling mechanism and a power mechanism; the gripping mechanism comprises a left clamping ring, a right clamping ring, a left clamping wheel and a right clamping wheel, the left clamping ring and the left clamping wheel are respectively controlled by an upper electric telescopic rod and a lower electric telescopic rod, and a motor drives the electric telescopic rods to stretch; the joint position of the grasping mechanism is fixedly connected by a pin, and the left clamping ring and the left clamping wheel are connected in a pin connection mode and are fixed on the upper fixing plate and the lower fixing plate; the travelling mechanism comprises a driving wheel, a driven wheel, a motor, a reduction box and a vehicle body; the vehicle body, the motor and the reduction gearbox are fixed on the fixing plate together, the driven wheel and the driving wheel are fixed on the vehicle body and are fixed in the vertical direction, the driving wheel is arranged below the vehicle body, and the driven wheel is arranged above the vehicle body; the vibration excitation mechanism comprises a vibration excitation motor, a reduction gearbox, a diaphragm type coupler, a helical gear and an eccentric block; the exciting motor is connected with a belt wheel shaft in the reduction box through a diaphragm type coupler, and the belt wheel shaft is connected with a belt wheel to reduce the rotating speed provided by the exciting motor, transmit the reduced rotating speed to the eccentric block input shaft through the diaphragm type coupler and be connected with the helical gear.

2. The tree-climbing vibration harvester according to claim 1, characterized in that: the outer side of the clamping ring is designed by an external pin, so that the electric rod can control the left clamping ring and the right clamping ring 2 to open and close; plastic washers are added on the inner sides of the left clamping ring and the right clamping ring 2.

3. A tree-climbing vibration harvester according to claim 2, characterized in that: the left clamping ring and the right clamping ring of the grasping mechanism control the final clamping radius of the clamping rings by controlling the expansion and contraction of the electric rods.

4. The tree-climbing vibration harvester of claim 1, characterized in that: the left clamping wheel and the right clamping wheel in the grasping mechanism are respectively connected through an axle, the axle is connected with the fixing rod through a screw, and the wheel is connected with the axle through a fixing pin; the fixed rod is hollow, and two pin holes are reserved and are respectively connected with the fixed frame and the electric telescopic rod at the lower part of the fixed plate through revolute pairs; the electric telescopic rod is connected with the fixing frame on the upper part of the fixing plate through a pin.

5. The tree-climbing vibration harvester of claim 1, characterized in that: the motor is the same as the exciting motor.

6. The tree-climbing vibration harvester of claim 1, characterized in that: the driving wheel and the driven wheel are the same in size, and tires of the driving wheel and the driven wheel are concave.