Four-way shuttle vehicle and running driving assembly

Abstract

The utility model discloses a four-way shuttle vehicle and a running driving assembly, the four-way shuttle vehicle comprises two chassis assemblies, and the two chassis assemblies are connected through a cam mechanism so as to replace the chassis assembly in contact with a guide rail surface; a driving wheel and at least one driven wheel are arranged on each of two opposite side parts of a chassis of the chassis assembly, and each driven wheel is provided with a wheel surface moving on a guide rail surface and a limiting flange arranged on the inner side wall of a guide rail; and the distance between the driven wheels on the two side parts is set to enable the wheel surfaces of the driven wheels on the two side parts to be at least not separated from the guide rail surface. According to the driving wheel assembly, the driven wheel abuts against the inner side of the track, so that the vehicle can stably run on the track in a positioned mode, and the requirements for the track and the structure of the driving wheel can be lowered. The four-way shuttle vehicle is adopted, reversing running is achieved by replacing the two chassis assemblies running in different directions, the chassis assemblies adopt the design of the running wheel assemblies, and the requirements for the structure of the rail and the structure of the driving wheel are reduced as well.

Description

Technical Field

[0001] The utility model relates to the technical field of rail transport trolleys, in particular to a four-way shuttle vehicle and a travel drive assembly. Background Art

[0002] There are two main forms of shuttle vehicles in warehousing and logistics equipment: shuttle vehicle in-and-out storage system and shuttle vehicle storage system. The shuttle vehicles run on fixed tracks in a reciprocating or looping manner to transport goods to designated locations or docking equipment.

[0003] As for the existing shuttle vehicle structure, a drive motor and a transmission mechanism are mostly used to drive the wheels of the four-way shuttle vehicle to move. Each traveling wheel is a driving wheel to adapt to the unevenness of the guide rail, and the movement of the shuttle vehicle to the target position is mostly adjusted by steering. This type of chassis needs to accommodate a complex transmission structure and provide space for the driving wheel to move. In addition, the steering will change the position of the shuttle vehicle relative to the working plane during the movement, which will also affect the positioning accuracy and efficient operation of the shuttle vehicle.

[0004] Therefore, the existing shuttle vehicle adopts a motor to coordinate the steering and each wheel body is a driving wheel, which leads to a complex structure and control drive of the shuttle vehicle, which is not conducive to the actual debugging and application of the shuttle vehicle and efficient operation.

[0005] In addition, to keep the driving wheels moving stably on the track, high requirements are placed on the track structure or the structure of the driving wheels. Utility Model Content

[0006] The purpose of the utility model is to provide a four-way shuttle and a travel drive assembly to solve the technical problem in the prior art that the shuttle structure and control drive are complicated, which is not conducive to the actual debugging and application of the shuttle, because the existing shuttle adopts a motor to coordinate the steering and each wheel body is a driving wheel.

[0007] In order to solve the above technical problems, the utility model specifically provides the following technical solutions:

[0008] A four-way shuttle vehicle comprises two chassis assemblies, the travel directions of the two chassis assemblies are set to be perpendicular to each other, and the two chassis assemblies are connected by a cam mechanism, and the cam mechanism is used to make the two chassis assemblies move relative to each other to replace the chassis assembly in contact with the guide rail surface to change the direction of travel;

[0009] The chassis components at least have a chassis, and a driving wheel and at least one driven wheel are arranged on two opposite sides of the chassis, and the driven wheel has a wheel surface moving on the guide rail surface and a limiting rib arranged on the inner side wall of the guide rail;

[0010] The distance between the driven wheels on both sides is arranged so that the wheel surfaces of the driven wheels on both sides at least do not deviate from the guide rail surface.

[0011] As a preferred solution of the utility model, the driven wheels are provided in two, one driven wheel is provided in front of and behind the driving wheel in the driving direction;

[0012] The driven wheel comprises a rubber-coated wheel body, one side of the rubber-coated wheel body is concentrically provided with the limiting rib, and the rubber-coated wheel body is connected to the chassis via a rotating shaft.

[0013] As a preferred solution of the utility model, the driving wheel is connected to the chassis via a suspension shock-absorbing structure;

[0014] The suspension shock absorbing structure comprises a fixing frame fixedly arranged on the chassis, the fixing frame has a mounting groove opened along the axial direction of the driving wheel, and two guide rods are arranged in the mounting groove along the radial direction of the driving wheel;

[0015] The shaft end of the driving wheel is set on the guide rod through a mounting block, and the mounting block can move along the length direction of the guide rod. A spring sleeved on the guide rod is arranged between the mounting block and the top inner wall of the mounting groove, and the force of the spring on the mounting block is always downward along the axial direction of the guide rod.

[0016] As a preferred solution of the utility model, the driving wheel is a hub motor, and the hub surface of the hub motor travels on the guide rail surface.

[0017] As a preferred solution of the utility model, one of the chassis of the two chassis assemblies is located above the other chassis;

[0018] A plurality of guide shafts are vertically distributed on one of the chassis;

[0019] A plurality of bushings matched with the guide shafts are arranged on the other chassis.

[0020] As a preferred solution of the utility model, two support frames are symmetrically arranged on the chassis located below, the cam mechanism is arranged on the top of the two support frames, and a slot for the support frames to pass through is arranged in the middle of the chassis located below;

[0021] The cam mechanism comprises a rotating shaft mounted on the top of the two support frames, the rotating shaft is rotatably connected to the support frames, and a cam is arranged at the end of the rotating shaft located outside the support frames; a reversing block is arranged on the upper chassis, and a groove matching the cam is arranged on the surface of the reversing block facing the cam;

[0022] The cam is rotated by rotating the rotating shaft, driving the reversing block to move up and down relative to the support frame, thereby causing the two chassis to move relative to each other to replace the chassis component that contacts the guide rail surface.

[0023] The present invention provides a travel drive assembly, comprising a chassis, wherein a driving wheel and at least one driven wheel are arranged on two opposite sides of the chassis, wherein the driven wheel has a wheel surface moving on a guide rail surface, and a limit retaining edge abutting against an inner side wall of the guide rail;

[0024] The distance between the driven wheels on both sides is arranged so that the wheel surfaces of the driven wheels on both sides at least do not deviate from the guide rail surface.

[0025] As a preferred solution of the present invention, two driven wheels are provided, one driven wheel is provided in front of and behind the driving wheel in the driving direction;

[0026] The driven wheel comprises a rubber-coated wheel body, one side of the rubber-coated wheel body is concentrically provided with the limiting rib, and the rubber-coated wheel body is connected to the chassis via a rotating shaft.

[0027] As a preferred solution of the present invention, the driving wheel is a hub motor, and the wheel hub surface of the hub motor travels on the guide rail surface.

[0028] As a preferred solution of the present invention, the driving wheel is connected to the chassis via a suspension shock-absorbing structure;

[0029] The suspension shock absorbing structure comprises a fixing frame fixedly arranged on the chassis, the fixing frame has a mounting groove opened along the axial direction of the driving wheel, and two guide rods are arranged in the mounting groove along the radial direction of the driving wheel;

[0030] The shaft end of the driving wheel is set on the guide rod through a mounting block, and the mounting block can move along the length direction of the guide rod. A spring sleeved on the guide rod is arranged between the mounting block and the top inner wall of the mounting groove, and the force of the spring on the mounting block is always downward along the axial direction of the guide rod.

[0031] Compared with the prior art, the utility model has the following beneficial effects:

[0032] The four-way shuttle provided by the utility model is equipped with two sets of driving wheel groups, and the contact between the two sets of driving wheel groups and the guide rail surface is achieved by reversing, so that the shuttle in the utility model can move freely in four directions on a working plane with plane coordinate system construction conditions. The four-way shuttle of the utility model has a simple structure, has no guiding requirements for the guide rail of the shuttle, and can weaken the structural design of the guide rail, and has strong adaptability.

[0033] The utility model also provides a traveling wheel assembly, which adopts a method in which a driven wheel abuts against the inner side of a track to allow the vehicle to stably position and travel on the track, which can reduce the requirements on the structure of the track itself and the driving wheel, and can be used for the straight-line travel of the trolley or as an accessory for a four-way shuttle vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the implementation or the prior art description. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0035] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the utility model;

[0036] Figure 2 This is a structural schematic diagram of the first chassis member of the vehicle body of the embodiment of the utility model;

[0037] Figure 3 It is a partial structural schematic diagram of the second chassis member of the trolley body of the embodiment of the utility model;

[0038] Figure 4 This is a schematic diagram of the connection structure between the first driving wheel or the second driving wheel and the suspension shock absorbing structure of an embodiment of the utility model;

[0039] Figure 5 It is a schematic structural diagram of the first driven wheel or the second driven wheel in an embodiment of the utility model.

[0040] The numbers in the figure represent the following:

[0041] 10-chassis assembly; 20-cam mechanism; 30-suspension shock absorbing structure; 40-support frame; 50-slot; 60-guide shaft; 61-limiting block; 70-sleeve;

[0042] 11- chassis; 12- driving wheel; 13- driven wheel; 14- limiting rib;

[0043] 21-rotating shaft; 22-cam; 23-steering block;

[0044] 31-fixed frame; 32-mounting block; 33-guide rod; 34-mounting slot; 35-spring;

[0045] 131-rubber-coated wheel body; 132-rotating shaft. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0047] like Figures 1 to 5 As shown, the utility model provides a four-way shuttle vehicle, including two chassis assemblies 10, the travel directions of the two chassis assemblies 10 are set to be perpendicular to each other, and the two chassis assemblies 10 are connected by a cam mechanism 20, and the cam mechanism 20 is used to make the two chassis assemblies 10 move relative to each other to replace the chassis assembly 10 that contacts the guide rail surface to change the direction of travel.

[0048] The chassis assembly 10 at least comprises a chassis 11, on which two opposite sides are provided a driving wheel 12 and at least one driven wheel 13, the driven wheel 13 having a wheel surface moving on the guide rail surface and a limiting rib 14 provided on the inner side wall of the guide rail.

[0049] The distance between the driven wheels 13 on both sides is arranged so that the wheel surfaces of the driven wheels 13 on both sides at least do not deviate from the guide rail surface.

[0050] The four-way shuttle provided in this embodiment is assembled by two sets of driving chassis, and the contact between the two sets of driving chassis and the guide rail surface is achieved by reversing. Specifically, the driving wheel 12 and the driven wheel 13 (referring to the two sides of the chassis 11) of one chassis assembly 10 (the first chassis assembly) are in contact with the guide rail surface, and there is a certain gap between the driving wheel 12 and the driven wheel 13 of the other chassis assembly (the second chassis assembly) and the guide rail surface.

[0051] When reversing, the cam structure 20 rotates, and the chassis 11 of the second chassis assembly drops as a whole, and its driving wheel 12 and driven wheel 13 contact the guide rail surface. As the cam of the cam structure 20 rotates, the second chassis assembly becomes the supporting chassis of the four-way shuttle and contacts the guide rail surface, and the first chassis assembly moves away from the guide rail surface, achieving a 90° reversal, so that the shuttle in the utility model can move freely in four directions on a working plane with the conditions for constructing a plane coordinate system.

[0052] The four-way shuttle has a simple structure and can weaken the design of the guide rail structure, and has strong adaptability.

[0053] There are two driven wheels 13, one driven wheel 13 is arranged in front and behind the driving wheel 12 in the driving direction, and the driven wheel 13 includes a rubber-coated wheel body 131, and a limiting rib 14 is concentrically arranged on one side of the rubber-coated wheel body 131. The rubber-coated wheel body 131 is connected to the chassis 11 through a rotating shaft 132.

[0054] The driving wheel 12 is a hub motor, and the hub surface of the hub motor runs on the guide rail surface, that is, the chassis structure of the four-way shuttle vehicle uses the hub motor directly as the driving wheel, which simplifies the driving mechanism of the chassis and reduces the overall height of the chassis, thereby helping to reduce the overall center of gravity height.

[0055] The four-way shuttle provided in this embodiment specifically sets a driving wheel in the middle of the side of the chassis, that is, the driving wheel 12 is located in the middle of the side of the chassis, and the driven wheels 13 are arranged in front and rear of the driving wheel 12, and the front and rear are specifically in terms of the direction in which the driving wheel 12 moves.

[0056] A limiting structure is provided on the driven wheel 13, that is, by setting the limiting rib 14 on the unobstructed side of the guide rail and abutting against the side of the guide rail, there is no need to set a rib on the guide rail structure for the shuttle vehicle to travel, thereby simplifying the guide rail structure of the shuttle vehicle.

[0057] The limit baffle 14 does not rotate synchronously with the driven wheel 13, and rotates only when it collides with the side of the guide rail surface, so that the limit baffle 14 and the side of the guide rail are in line contact, reducing the resistance during the movement of the trolley.

[0058] Furthermore, the limiting rib on the driven wheel 13 of the four-way shuttle in this embodiment is rotatably connected to the driven wheel 13. At this time, the limiting baffle 14 is specifically annular or disc-shaped, and its diameter is larger than the driven wheel 13. After contacting the guide rail, it can rotate relative to the shuttle rail to reduce the resistance when the rib contacts the guide rail.

[0059] The driving wheel 12 of the four-way shuttle vehicle is provided with a suspension shock-absorbing structure 30 , through which the driving wheel 12 can adapt to a guide rail with certain undulations, thereby increasing compatibility with the unevenness of the guide rail of the trolley. The driving wheel 12 is connected to the chassis 11 via the suspension shock-absorbing structure 30 .

[0060] The suspension shock absorbing structure 30 includes a fixing frame 31 fixedly arranged on the chassis 11 . The fixing frame 31 has a mounting groove 34 opened along the axial direction of the driving wheel 12 . Two guide rods 33 are arranged in the mounting groove 34 along the radial direction of the driving wheel 12 .

[0061] The axial end of the driving wheel 12 is set on the guide rod 33 through the mounting block 32. The mounting block 32 can move along the length direction of the guide rod 33. A spring 35 is provided between the mounting block 32 and the top inner wall of the mounting groove 34 and is sleeved on the guide rod 33. The force of the spring 35 on the mounting block 32 is always downward along the axial direction of the guide rod 33, that is, the spring 35 is required to always apply a downward force to the driving wheel 12, so that the wheel surface of the driving wheel 12 is always in stably contact with the guide rail surface.

[0062] Under the action of the force of the spring 35, it is ensured that the driving wheel 12 is always in effective contact with the guide rail surface, and sufficient pressure is exerted on the guide rail to prevent the four-way shuttle from slipping during operation.

[0063] In this embodiment, one of the chassis 11 of the two chassis assemblies 10 is located above the other chassis 11; in order to avoid vibration during the switching process or when the shuttle vehicle moves on the special-shaped guide rail, which causes the upper and lower chassis 11 to contact, a plurality of guide shafts 60 are vertically distributed on one of the chassis 11; a plurality of sleeves 70 cooperating with the guide shafts 60 are arranged on the other chassis 11, and a limiting block 61 is arranged on the top of the guide shaft 60.

[0064] The guide shaft 60 is provided with a limit block 61 for limiting the relative movement position between the upper and lower chassis 11. The limit direction is concentric with the axial direction of the guide shaft, which increases the contact area between the two chassis during driving, reduces the force between the bearing and the shaft, and prolongs the life of the guide shaft.

[0065] Two support frames 40 are symmetrically arranged on the bottom chassis 11 , a cam mechanism 20 is arranged on the top of the two support frames 40 , and a slot 50 for the support frames 40 to pass through is arranged in the middle of the bottom chassis 11 .

[0066] The cam mechanism 20 includes a rotating shaft 21 installed on the top of two support frames 40. The rotating shaft 21 is rotatably connected to the support frames 40, and a cam 22 is provided at the end of the rotating shaft 21 located outside the support frames 40; a reversing block 23 is provided on the chassis 11 located above, and a groove 50 matching the cam 22 is provided on the surface of the reversing block 23 facing the cam 22.

[0067] The cam 22 is rotated by rotating the rotating shaft 21, driving the reversing block 23 to move up and down relative to the support frame 40, thereby causing the two chassis 11 to move relative to each other to replace the chassis assembly 10 that contacts the guide rail surface.

[0068] like Figure 2 or Figure 3 As shown, the utility model provides a travel drive assembly, including a chassis 11, a driving wheel 12 and at least one driven wheel 13 are arranged on two opposite sides of the chassis 11, and the driven wheel 13 has a wheel surface moving on the guide rail surface, and a limiting retaining edge 14 abutting against the inner side wall of the guide rail;

[0069] The distance between the driven wheels 13 on both sides is arranged so that the wheel surfaces of the driven wheels 13 on both sides at least do not deviate from the guide rail surface.

[0070] There are two driven wheels 13, one driven wheel 13 is arranged in front of and behind the driving wheel 12 in the driving direction, and the driven wheel 13 includes a rubber-coated wheel body 131, and the limiting rib 14 is concentrically arranged on one side of the rubber-coated wheel body 131. The rubber-coated wheel body 131 is connected to the chassis 11 through a rotating shaft 132.

[0071] The limiting ribs 14 of the driven wheels 13 on both sides of the chassis 11 are both located at the inner side of the driven wheels 13 .

[0072] Or the limiting rib 14 of one of the driven wheels 13 on the same side of the chassis 11 is located at the inner side of the driven wheel 13 , and the limiting rib 14 of another driven wheel 13 is located at the outer side of the driven wheel 13 .

[0073] The driving wheel 12 is a hub motor, and the hub surface of the hub motor runs on the guide rail surface.

[0074] like Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, the driving wheel 12 is connected to the chassis 11 through a suspension damping structure 30. The driving wheel 12 of the four-way shuttle vehicle has a suspension damping structure 30, which enables the driving wheel 12 to adapt to a guide rail with certain undulations, thereby increasing compatibility with unevenness of the trolley guide rail.

[0075] The suspension shock absorbing structure 30 includes a fixing frame 31 fixedly mounted on the chassis 11. The fixing frame 31 has a mounting groove 34 opened along the axial direction of the driving wheel 12. Two guide rods 33 are arranged in the mounting groove 34 along the radial direction of the driving wheel 12. The two guide rods 33 can ensure that the mounting block 32 moves up and down stably along the guide rods 33.

[0076] The axial end of the driving wheel 12 is set on the guide rod 33 through the mounting block 32. The mounting block 32 can move along the length direction of the guide rod 33. A spring 35 sleeved on the guide rod 33 is provided between the mounting block 32 and the top inner wall of the mounting groove 34. The force of the spring 35 on the mounting block 32 is always downward along the axial direction of the guide rod 33.

[0077] In this embodiment, the suspension shock-absorbing structure 30 of the driving wheel 12 is controlled by the compression limit of the spring 35 and the springs 35 are provided on the upper and lower ends of the mounting block 32, so that the mounting block 32 has upper and lower limits, which constrains the floating range of the driving wheel 12. The pressure of the suspension shock-absorbing structure 39 on the driving wheel 12 can be controlled within a certain range, so that the driving wheel 12 fits the guide rail surface, ensuring smooth operation of the trolley during the process.

[0078] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A four-way shuttle vehicle, characterized in that: The vehicle comprises two chassis assemblies (10), the travel directions of the two chassis assemblies (10) being arranged to be perpendicular to each other, and the two chassis assemblies (10) being connected via a cam mechanism (20), the cam mechanism (20) being used to cause the two chassis assemblies (10) to move relative to each other so as to replace the chassis assembly (10) in contact with the guide rail surface, so as to change the direction of travel; The chassis assembly (10) at least comprises a chassis (11), and a driving wheel (12) and at least one driven wheel (13) are arranged on two opposite sides of the chassis (11), and the driven wheel (13) has a wheel surface that moves on the guide rail surface, and a limiting retaining edge (14) arranged on the inner side wall of the guide rail; The distance between the driven wheels (13) on both sides is arranged so that the wheel surfaces of the driven wheels (13) on both sides at least do not deviate from the guide rail surface.

2. A four-way shuttle vehicle according to claim 1, characterized in that: The driven wheels (13) are provided in two numbers, one driven wheel (13) being provided in front of and behind the driving wheel (12) in the travel direction; The driven wheel (13) comprises a rubber-coated wheel body (131), the limiting retaining edge (14) being coaxially arranged on one side of the rubber-coated wheel body (131), and the rubber-coated wheel body (131) being connected to the chassis (11) via a rotating shaft (132).

3. A four-way shuttle vehicle according to claim 1, characterized in that: The driving wheel (12) is connected to the chassis (11) via a suspension shock-absorbing structure (30); The suspension shock absorbing structure (30) comprises a fixing frame (31) fixedly arranged on the chassis (11), the fixing frame (31) having a mounting groove (34) opened along the axial direction of the driving wheel (12), and two guide rods (33) are arranged in the mounting groove (34) along the radial direction of the driving wheel (12); The shaft end of the driving wheel (12) is arranged on the guide rod (33) via a mounting block (32); the mounting block (32) is movable along the length direction of the guide rod (33); a spring (35) sleeved on the guide rod (33) is arranged between the mounting block (32) and the top inner wall of the mounting groove (34); the force of the spring (35) on the mounting block (32) is always downward along the axial direction of the guide rod (33).

4. A four-way shuttle according to any one of claims 1 to 3, characterized in that: The driving wheel (12) is a wheel hub motor, and the wheel hub surface of the wheel hub motor travels on the guide rail surface.

5. The four-way shuttle vehicle according to claim 1, characterized in that: One of the chassis (11) of the two chassis assemblies (10) is located above the other chassis (11); A plurality of guide shafts (60) are vertically distributed on one of the chassis (11); A plurality of shaft sleeves cooperating with the guide shaft (60) are arranged on the other chassis (11).

6. A four-way shuttle vehicle according to claim 5, characterized in that: Two support frames (40) are symmetrically arranged on the bottom chassis (11), the cam mechanisms (20) are arranged on the tops of the two support frames (40), and a slot (50) for the support frames (40) to pass through is arranged in the middle of the bottom chassis (11); The cam mechanism (20) comprises a rotating shaft (21) mounted on the top of the two support frames (40), the rotating shaft (21) being rotatably connected to the support frames (40), and a cam (22) being arranged at an end of the rotating shaft (21) located outside the support frames (40); a reversing block (23) is arranged on the upper chassis (11), and a surface of the reversing block (23) facing the cam (22) is provided with a slot (50) matching the cam (22); The cam (22) is rotated by rotating the rotating shaft (21), driving the reversing block (23) to move up and down relative to the support frame (40), thereby causing the two chassis (11) to move relative to each other to replace the chassis assembly (10) in contact with the guide rail surface.

7. A travel drive assembly, characterized in that: It comprises a chassis (11), wherein a driving wheel (12) and at least one driven wheel (13) are arranged on two opposite sides of the chassis (11), and the driven wheel (13) has a wheel surface that moves on a guide rail surface, and a limiting retaining edge (14) that abuts against an inner side wall of the guide rail; The distance between the driven wheels (13) on both sides is arranged so that the wheel surfaces of the driven wheels (13) on both sides at least do not deviate from the guide rail surface.

8. A travel drive assembly according to claim 7, characterized in that: The driven wheels (13) are provided in two numbers, one driven wheel (13) being provided in front of and behind the driving wheel (12) in the travel direction; The driven wheel (13) comprises a rubber-coated wheel body (131), the limiting retaining edge (14) being coaxially arranged on one side of the rubber-coated wheel body (131), and the rubber-coated wheel body (131) being connected to the chassis (11) via a rotating shaft (132).

9. A travel drive assembly according to claim 8, characterized in that: The driving wheel (12) is a wheel hub motor, and the wheel hub surface of the wheel hub motor travels on the guide rail surface.

10. A travel drive assembly according to any one of claims 7 to 9, characterized in that: The driving wheel (12) is connected to the chassis (11) via a suspension shock-absorbing structure (30); The suspension shock absorbing structure (30) comprises a fixing frame (31) fixedly arranged on the chassis (11), the fixing frame (31) having a mounting groove (34) opened along the axial direction of the driving wheel (12), and two guide rods (33) are arranged in the mounting groove (34) along the radial direction of the driving wheel (12); The shaft end of the driving wheel (12) is arranged on the guide rod (33) via a mounting block (32); the mounting block (32) is movable along the length direction of the guide rod (33); a spring (35) sleeved on the guide rod (33) is arranged between the mounting block (32) and the top inner wall of the mounting groove (34); the force of the spring (35) on the mounting block (32) is always downward along the axial direction of the guide rod (33).

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