Vehicle frame steering structure

Abstract

The utility model discloses a vehicle frame steering structure, which belongs to the technical field of vehicle frame steering, and comprises a chassis component, a steering control piece and a rear axle component, and the steering control piece is rotatably connected with the chassis component; the rear axle assembly is rotationally connected with the chassis assembly; the steering control piece and the rear axle assembly are connected in a rotating and sliding mode. According to the scheme, the chassis assembly and the rear axle assembly form a frame supporting structure together, the steering control piece can control the rotating direction of the front wheels and the rear wheels, the rear axle assembly, the chassis assembly and the steering control piece are of relatively independent structures, and when the steering control piece rotates, the rear axle assembly can swing along with the steering control piece; in addition, relative sliding can be generated between the steering control piece and the rear axle assembly, so that the rear axle assembly can only rotate, large forward displacement cannot be generated, and the turning radius of the frame can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to a vehicle frame structure, more specifically, to a vehicle frame steering structure. Background Art

[0002] The electric scooters for the elderly on the market are relatively large in size and have a large turning radius, making them inconvenient to use in relatively small spaces. For example, they are not easy to operate in a room. Users need to perform multiple forward and backward operations during the steering process to achieve a larger angle of turn, which greatly reduces the user experience.

[0003] For example: Chinese patent announcement number CN220833348U, announcement date April 26, 2024, the name of the utility model is a connecting rod four-wheel steering structure, the application discloses a steering structure of a vehicle frame, including a base connecting plate, a support frame is fixed on one side of the connecting plate, a clamping strip is fixed on one side of the bottom of the support frame, a sliding rod is slidably provided on the outer wall of the clamping strip, a connecting strip is fixed on one side of the sliding rod, a connecting strip is fixed on one side of the connecting strip, a connecting plate is fixed on one side of the connecting strip, a first connecting shaft is fixed on both sides of one side of the connecting plate, and a connecting rod is sleeved on the outer wall of the two first connecting shafts. The scheme is connected to the mounting base through an external steering shaft, and is also connected and fixed to the connecting plate. When the steering shaft is rotated, the connecting plate rotates, and the connecting plate rotates while being fixed to the connecting bar. The bottom connecting plate and the base connecting plate rotate with each other, thereby causing the support frame to slide on the sliding bar with the clamping strip, thereby causing the two movable wheels at the rear end to rotate together, realizing the four-wheel steering operation, thereby improving the practicality of the device. Utility Model Content

[0004] The utility model overcomes the problems of the existing frame being difficult to turn and having a large turning radius in a small space, and provides a frame steering structure. This solution can achieve the effect of a small turning radius of the frame and convenient steering, which provides convenience for users to use the scooter in a small space.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: a frame steering structure, including a chassis assembly, a steering control member and a rear axle assembly, wherein the steering control member is rotationally connected to the chassis assembly; the rear axle assembly is rotationally connected to the chassis assembly; and the steering control member and the rear axle assembly are rotationally and slidingly connected. In this solution, the chassis assembly and the rear axle assembly together constitute a frame support structure, the steering control member can control the rotation direction of the front and rear wheels, the rear axle assembly and the chassis assembly and the steering control member are relatively independent structures, and when the steering control member rotates, the rear axle assembly will also swing with the steering control member, and since relative sliding can also occur between the steering control member and the rear axle assembly, the rear axle assembly can only rotate and will not produce a large forward displacement, thereby effectively reducing the turning radius of the frame and providing convenience for users to use the scooter in a smaller space.

[0006] Preferably, the steering control member is provided with a slide groove, and the rear axle assembly is provided with a slider adapted to the slide groove. The sliding connection between the steering control member and the rear axle assembly is formed by the slide groove and the slider, wherein the slide groove can be provided on the steering control member, and the slider can be provided on the rear axle assembly.

[0007] Preferably, the rear axle assembly is provided with a slide groove, and the steering control member is provided with a slider adapted to the slide groove. The sliding connection between the steering control member and the rear axle assembly is formed by the slide groove and the slider, wherein the slide groove can be provided on the rear axle assembly and the slider can be provided on the steering control member.

[0008] Preferably, a first hinge shaft is provided on a side of the chassis assembly remote from the rear axle assembly, a steering control member being hingedly connected to the first hinge shaft, and a steering rod is further provided on the first hinge shaft. The steering rod, the steering control member, and the chassis assembly are hingedly connected together via the first hinge shaft, and when the steering rod rotates, the steering control member is driven to rotate together, thereby achieving rotation of the vehicle frame.

[0009] Preferably, a second hinge shaft is provided on a side of the chassis assembly proximate to the rear axle assembly, the second hinge shaft being hingedly connected to a side of the rear axle assembly distal from the steering control member. The chassis assembly and rear axle assembly are further hingedly connected together via the second hinge shaft, which is located at the rear of the chassis assembly and rear axle assembly to ensure rotation of the rear axle assembly.

[0010] Preferably, the chassis assembly is provided with a front wheel assembly on a side close to the first articulated shaft. The front wheel assembly is steered by a steering control member on the first articulated shaft to provide front steering for the vehicle frame.

[0011] Preferably, the rear axle assembly is provided with a rear wheel assembly on a side close to the second articulated shaft. The rear wheel assembly is controlled by the rear axle assembly and a steering control member on the first articulated shaft to provide rear-side steering for the vehicle frame.

[0012] Preferably, the steering control member is further provided with an auxiliary assembly, comprising a universal connecting rod, one end of which is rotatably connected to the steering control member, and the other end of which is rotatably connected to the front wheel assembly. The universal connecting rod connects the steering control member and the front wheel assembly, and rotation of the steering control member pulls the universal connecting rod, thereby driving the wheels of the front wheel assembly to steer.

[0013] Preferably, the pivot point between the universal joint and the steering control member is offset from the first hinge axis. To ensure that the universal joint controls the front wheel assembly, the distance between the hinge point of the universal joint on the steering control member and the front wheel assembly must be different from the distance between the first hinge axis and the front wheel assembly. In other words, the positions of the universal joint and the first hinge axis must be offset.

[0014] Preferably, the chassis assembly is provided with a reinforcement assembly, the reinforcement assembly comprising a connecting rod arranged in the chassis assembly. The reinforcement assembly is a connecting rod structure, which can be arranged on the chassis assembly to improve the structural strength of the chassis assembly and make the frame structure more stable.

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1) the present solution has the effect of a small turning radius of the frame and convenient steering, and can realize the turning of the frame in a relatively small space; (2) the structure is simple, the production cost is low, and it has good economic benefits; (3) the structural strength of the frame is higher and the stability performance is better, which can effectively improve the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a top view of the utility model in the initial state.

[0017] Figure 2 It is a bottom view of the utility model in the initial state.

[0018] Figure 3 It is a top view of the utility model in the right turning state.

[0019] Figure 4 It is a bottom view of the utility model in the right turning state.

[0020] Figure 5 It is a schematic diagram of the auxiliary components of the present invention.

[0021] Figure 6 This is an axonometric drawing of the present invention.

[0022] Figure 7 This is an exploded view of the present invention.

[0023] Figure 8 This is a schematic diagram of Example 2 of the present utility model.

[0024] In the figure: 1. Chassis assembly, 1.1. Base rod, 1.2. Articulated seat, 1.3. Connecting part, 2. Steering control part, 3. Rear axle assembly, 4. Slide groove, 5. Slider, 6. First articulated axis, 7. Second articulated axis, 8. Front wheel assembly, 8.1. Front wheel, 9. Rear wheel assembly, 9.1. Rear wheel, 10. Auxiliary assembly, 10.1. Universal connecting rod, 11. Reinforcement assembly, 11.1. Connecting rod. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be further described below with reference to specific embodiments and in conjunction with the accompanying drawings.

[0026] Example 1: Figures 1 to 7 The illustrated vehicle frame steering structure includes a chassis assembly 1, a steering control member 2, and a rear axle assembly 3, all of which are hingedly connected. Specifically, the steering control member 2 is arranged at the bottom of the front side (the side in which the vehicle frame moves forward) of the chassis assembly 1. The rear axle assembly 3 is an overall tripod structure, with the front side of the rear axle assembly 3 adjacent to the front side of the chassis assembly 1 and the rear side of the rear axle assembly 3 adjacent to the rear side of the chassis assembly 1. One end of the steering control member 2 is hingedly connected to the front side of the chassis assembly 1, while the other end of the steering control member 2 is rotatably connected to the front side of the rear axle assembly 3 and can also slide relative to it. The rear side of the chassis assembly 1 is hingedly connected to the rear side of the rear axle assembly 3. When the steering control member 2 rotates, the steering control member 2 drives the front side of the rear axle assembly 3 to rotate, and since relative sliding can occur between the steering control member 2 and the rear axle assembly 3, the steering control member 2 does not pull the rear axle assembly 3 to move forward and backward when rotating. The rear axle assembly 3 can only rotate and swing to a certain extent, so that the entire frame does not produce excessive forward displacement during the steering process, that is, the turning radius of the frame is reduced, which can provide users with a good turning experience in a smaller space.

[0027] Specifically, the chassis assembly 1 is a frame structure that is narrower at the front and wider at the rear. A base bar 1.1 is disposed at the front of the chassis assembly 1. A first hinge shaft 6 is disposed in the middle of the base bar 1.1. The first hinge shaft 6 is hingedly connected to the steering control member 2. An articulated seat 1.2 is disposed at the rear of the chassis assembly 1. A second articulated shaft 7 is disposed on the articulated seat 1.2. The articulated seat 1.2 is rotatably connected to the rear side of the rear axle assembly 3 via the second articulated shaft 7. In other words, both the steering control member 2 and the rear axle assembly 3 can rotate relative to the chassis assembly 1.

[0028] The steering control member 2 is a relatively short plate-like structure. The steering control member 2 is arranged at the bottom of the chassis assembly 1, and the front side of the steering control member 2 is hinged to the first hinge shaft 6, and the rear side of the steering control member 2 is connected to the front side of the rear axle assembly 3. Specifically, the rear axle assembly 3 is an isosceles triangle structure, and the front side of the rear axle assembly 3 is where the vertex is located. A slide groove 4 is provided on the front side of the rear axle assembly 3, and the direction of the slide groove 4 is along the front-to-back direction of the rear axle assembly 3. A slider 5 is provided on the rear side of the steering control member 2, and the slider 5 of the steering control member 2 can slide in the slide groove 4 on the rear axle assembly 3. When the vehicle frame is in the initial state, the steering control member 2 and the rear axle assembly 3 are both along the front-to-back direction of the vehicle frame. At this time, the slider 5 is located in the slide groove 4 away from the steering control member 2.

[0029] A steering rod (not shown in the figure) is also arranged at the location of the first articulated shaft 6. The steering rod is the direction control component of the entire frame and is arranged together with the first articulated shaft 6. When the steering rod is turned to the right, the first articulated shaft 6 rotates to the right and drives the steering control component 2 to rotate to the right. The steering control component 2 rotates with the location of the first articulated shaft 6 as the center of the circle. After the steering control component 2 rotates, the rear side of the steering control component 2 drives the rear axle assembly 3 to rotate to the left. At the same time, the slider 5 on the steering control component 2 slides in the slide groove 4 on the rear axle assembly 3, thereby preventing the steering control component 2 from pulling the rear axle assembly 3 forward during the rotation process. The rear axle assembly 3 can only rotate a certain angle with the rear wheel assembly 9 as the center of the circle. When the steering rod is rotated into place, the vehicle body can be started and a turn can be made. Similarly, when the steering rod is turned to the left, the principle is the same.

[0030] A front wheel assembly 8 is also provided on the front side of the chassis assembly 1. The front wheel assembly 8 includes two front wheels 8.1, one on each side of the base bar 1.1. Specifically, L-shaped connectors 1.3 are provided on each side of the base bar 1.1. The center of the connectors 1.3 is a hollow C-shaped structure. The center of the connectors 1.3 is sleeved over the ends of the base bar 1.1 to form a rotational connection. An auxiliary assembly 10 is also arranged on the steering control member 2. The auxiliary assembly 10 includes two sets of universal joints 10.1. The universal joints 10.1 are arranged between the connecting member 1.3 and the steering control member 2. Specifically, one end of the universal joint 10.1 is hinged to the steering control member 2 and located between the first hinge shaft 6 and the slider 5. The other end of the universal joint 10.1 is hinged to one end of the connecting member 1.3. The connecting member 1.3 is hinged to the universal joint 10.1 at one end, and the middle of the connecting member 1.3 is hinged to the end of the base rod 1.1. The other end of the connecting member 1.3 is fixed to the front wheel 8.1. The two sets of front wheels 8.1 and the two sets of universal joints 10.1 are symmetrically arranged on either side of the steering control member 2, with the hinge point between the connecting member 1.3 and the universal joint 10.1 located behind the base rod 1.1. A rear wheel assembly 9 is arranged at the rear side of the rear axle assembly 3 . The rear wheel assembly 9 includes two rear wheels 9 . 1 , which are rotatably connected to both sides of the rear portion of the rear axle assembly 3 .

[0031] When the steering rod rotates right, the front side of the steering control member 2 rotates rightward about the first articulation axis 6, while the rear side of the steering control member 2 swings leftward about the first articulation axis 6. At this point, both sets of universal joints 10.1 on the vehicle frame are displaced to the left. As a result, the left front wheel 8.1 is pushed by the left universal joint 10.1 and swings rightward under the action of the left connector 1.3. The right front wheel 8.1 is pulled by the right universal joint 10.1 and swings rightward under the action of the right connector 1.3, thus completing the rightward steering of the front wheel assembly 8. As the rear side of the steering control member 2 swings leftward, the steering control member 2 drives the front side of the rear axle assembly 3 to swing leftward, causing the entire rear axle assembly 3 to swing leftward, and driving both rear wheels 9.1 on the rear axle assembly 3 to swing leftward synchronously. This synchronizes the rotation of the front and rear wheel assemblies 8 and 9 on the vehicle frame, with the front and rear wheel assemblies rotating in opposite directions, ensuring that the vehicle frame can turn and move forward normally. Similarly, when the steering rod is turned to the left, the principle is the same.

[0032] It should be noted that the rotation angle of the steering control member 2 is related to the position of the chute 4 and the slider 5. When the slider 5 is located behind the chute 4, the vehicle frame is in its initial state. When the slider 5 is located in front of the chute 4, the vehicle frame is in its maximum rotation angle position for turning left or right. Therefore, the length of the chute 4 limits the maximum steering angle of the vehicle frame to a certain extent. Of course, a limit block (not shown) can also be arranged at the bottom of the base rod 1.1 to limit the maximum steering angle of the vehicle frame. Specifically, the limit block can be arranged on one side of the connecting member 1.3 to limit the maximum rotation angle of the connecting member 1.3, that is, to limit the maximum steering angle of the vehicle frame.

[0033] A reinforcement assembly 11 is also arranged on the chassis assembly 1. Specifically, connecting rods 11.1 connected horizontally and vertically are arranged in the frame of the chassis assembly 1. The connecting rods 11.1 are welded to the chassis assembly 1 to ensure the overall strength and stability of the chassis assembly 1 and improve the safety performance of the frame.

[0034] It should be noted that, in this embodiment, the front side and the rear side are relative to the side of the frame in the forward direction and the side of the frame in the reverse direction.

[0035] Example 2: Figure 8 Combined with Figures 1 to 7 The illustrated vehicle frame steering structure includes a chassis assembly 1, a steering control member 2, and a rear axle assembly 3, all of which are hingedly connected. Specifically, the steering control member 2 is arranged at the bottom of the front side (the side in which the vehicle frame moves forward) of the chassis assembly 1. The rear axle assembly 3 is an overall tripod structure, with the front side of the rear axle assembly 3 adjacent to the front side of the chassis assembly 1 and the rear side of the rear axle assembly 3 adjacent to the rear side of the chassis assembly 1. One end of the steering control member 2 is hingedly connected to the front side of the chassis assembly 1, while the other end of the steering control member 2 is rotatably connected to the front side of the rear axle assembly 3 and can also slide relative to it. The rear side of the chassis assembly 1 is hingedly connected to the rear side of the rear axle assembly 3. When the steering control member 2 rotates, the steering control member 2 drives the front side of the rear axle assembly 3 to rotate, and since relative sliding can occur between the steering control member 2 and the rear axle assembly 3, the steering control member 2 does not pull the rear axle assembly 3 to move forward and backward when rotating. The rear axle assembly 3 can only rotate and swing to a certain extent, so that the entire frame does not produce excessive forward displacement during the steering process, that is, the turning radius of the frame is reduced, which can provide users with a good turning experience in a smaller space.

[0036] Specifically, the chassis assembly 1 is a frame structure that is narrower at the front and wider at the rear. A base bar 1.1 is disposed at the front of the chassis assembly 1. A first hinge shaft 6 is disposed in the middle of the base bar 1.1. The first hinge shaft 6 is hingedly connected to the steering control member 2. An articulated seat 1.2 is disposed at the rear of the chassis assembly 1. A second articulated shaft 7 is disposed on the articulated seat 1.2. The articulated seat 1.2 is rotatably connected to the rear side of the rear axle assembly 3 via the second articulated shaft 7. In other words, both the steering control member 2 and the rear axle assembly 3 can rotate relative to the chassis assembly 1.

[0037] The steering control member 2 is a relatively short plate-like structure. The steering control member 2 is arranged at the bottom of the chassis assembly 1, and the front side of the steering control member 2 is hinged to the first hinge shaft 6, and the rear side of the steering control member 2 is connected to the front side of the rear axle assembly 3. Specifically, the rear axle assembly 3 is an isosceles triangle structure, and the front side of the rear axle assembly 3 is where the vertex is located. A slider 5 is provided on the front side of the rear axle assembly 3, and a slide groove 4 is provided on the rear side of the steering control member 2. The direction of the slide groove 4 is along the front-to-back direction of the steering control member 2, and the slider 5 of the rear axle assembly 3 can slide in the slide groove 4 on the steering control member 2. When the vehicle frame is in the initial state, the steering control member 2 and the rear axle assembly 3 are both along the front-to-back direction of the vehicle frame. At this time, the slider 5 is located in the slide groove 4 away from the rear axle assembly 3.

[0038] A steering rod (not shown in the figure) is also arranged at the location of the first articulated shaft 6. The steering rod is the direction control component of the entire frame and is arranged together with the first articulated shaft 6. When the steering rod is turned to the right, the first articulated shaft 6 rotates to the right and drives the steering control component 2 to rotate to the right. The steering control component 2 rotates with the location of the first articulated shaft 6 as the center of the circle. After the steering control component 2 rotates, the rear side of the directional control component 2 drives the rear axle assembly 3 to rotate to the left. At the same time, the slider 5 on the rear axle assembly 3 slides in the slide groove 4 on the steering control component 2, thereby preventing the steering control component 2 from pulling the rear axle assembly 3 forward during the rotation process. The rear axle assembly 3 can only rotate to a certain angle with the rear wheel assembly 9 as the center of the circle. When the steering rod is rotated into place, the vehicle body can be started and a turn can be made. Similarly, when the steering rod is turned to the left, the principle is the same.

[0039] A front wheel assembly 8 is also provided on the front side of the chassis assembly 1. The front wheel assembly 8 includes two front wheels 8.1, one on each side of the base bar 1.1. Specifically, L-shaped connectors 1.3 are provided on each side of the base bar 1.1. The center of the connectors 1.3 is a hollow C-shaped structure. The center of the connectors 1.3 is sleeved over the ends of the base bar 1.1 to form a rotational connection. An auxiliary assembly 10 is also arranged on the steering control member 2. The auxiliary assembly 10 includes two sets of universal joints 10.1. The universal joints 10.1 are arranged between the connecting member 1.3 and the steering control member 2. Specifically, one end of the universal joint 10.1 is hinged to the steering control member 2 and located between the first hinge axis 6 and the slide groove 4. The other end of the universal joint 10.1 is hinged to one end of the connecting member 1.3. The connecting member 1.3 is hinged to the universal joint 10.1 at one end, and the middle of the connecting member 1.3 is hinged to the end of the base rod 1.1. The other end of the connecting member 1.3 is fixed to the front wheel 8.1. The two sets of front wheels 8.1 and the two sets of universal joints 10.1 are symmetrically arranged on either side of the steering control member 2, with the hinge point between the connecting member 1.3 and the universal joint 10.1 located behind the base rod 1.1. A rear wheel assembly 9 is arranged at the rear side of the rear axle assembly 3 . The rear wheel assembly 9 includes two rear wheels 9 . 1 , which are rotatably connected to both sides of the rear portion of the rear axle assembly 3 .

[0040] When the steering rod rotates right, the front side of the steering control member 2 rotates rightward about the first articulation axis 6, while the rear side of the steering control member 2 swings leftward about the first articulation axis 6. At this point, both sets of universal joints 10.1 on the vehicle frame are displaced to the left. As a result, the left front wheel 8.1 is pushed by the left universal joint 10.1 and swings rightward under the action of the left connector 1.3. The right front wheel 8.1 is pulled by the right universal joint 10.1 and swings rightward under the action of the right connector 1.3, thus completing the rightward steering of the front wheel assembly 8. As the rear side of the steering control member 2 swings leftward, the steering control member 2 drives the front side of the rear axle assembly 3 to swing leftward, causing the entire rear axle assembly 3 to swing leftward, and driving both rear wheels 9.1 on the rear axle assembly 3 to swing leftward synchronously. This synchronizes the rotation of the front and rear wheel assemblies 8 and 9 on the vehicle frame, with the front and rear wheel assemblies rotating in opposite directions, ensuring that the vehicle frame can turn and move forward normally. Similarly, when the steering rod is turned to the left, the principle is the same.

[0041] It should be noted that the rotation angle of the steering control member 2 is related to the position of the chute 4 and the slider 5. When the slider 5 is located in front of the chute 4, the vehicle frame is in its initial state. When the slider 5 is located behind the chute 4, the vehicle frame is in its maximum rotation angle position for turning left or right. Therefore, the length of the chute 4 limits the maximum steering angle of the vehicle frame to a certain extent. Of course, a limit block (not shown) can also be arranged at the bottom of the base rod 1.1 to limit the maximum steering angle of the vehicle frame. Specifically, the limit block can be arranged on one side of the connecting member 1.3 to limit the maximum rotation angle of the connecting member 1.3, that is, to limit the maximum steering angle of the vehicle frame.

[0042] A reinforcement assembly 11 is also arranged on the chassis assembly 1. Specifically, connecting rods 11.1 connected horizontally and vertically are arranged in the frame of the chassis assembly 1. The connecting rods 11.1 are welded to the chassis assembly 1 to ensure the overall strength and stability of the chassis assembly 1 and improve the safety performance of the frame.

[0043] It should be noted that, in this embodiment, the front side and the rear side are relative to the side of the frame in the forward direction and the side of the frame in the reverse direction.

Claims

1. A frame steering structure, characterized in that: include chassis components; a steering control member, the steering control member being rotatably connected to the chassis assembly; a rear axle assembly, the rear axle assembly being rotatably connected to the chassis assembly; The steering control component and the rear axle assembly are connected in a rotational and sliding manner.

2. A frame steering structure according to claim 1, characterized in that: The steering control component is provided with a slide groove, and the rear axle assembly is provided with a sliding block adapted to the slide groove.

3. A frame steering structure according to claim 1, characterized in that: The rear axle assembly is provided with a slide groove, and the steering control component is provided with a sliding block adapted to the slide groove.

4. A frame steering structure according to claim 2 or 3, characterized in that: A first articulated shaft is provided on a side of the chassis assembly away from the rear axle assembly. A steering control component is hinged on the first articulated shaft. A steering rod is also provided on the first articulated shaft.

5. A frame steering structure according to claim 4, characterized in that: A second articulated shaft is provided on a side of the chassis assembly close to the rear axle assembly, and the second articulated shaft is hinged to a side of the rear axle assembly away from the steering control component.

6. The frame steering structure according to claim 4, characterized in that: A front wheel assembly is provided on one side of the chassis assembly close to the first hinge shaft.

7. The frame steering structure according to claim 5, characterized in that: A rear wheel assembly is provided on one side of the rear axle assembly close to the second articulated shaft.

8. The frame steering structure according to claim 6, characterized in that: The steering control member is also provided with an auxiliary component, which includes a universal connecting rod, one end of which is rotatably connected to the steering control member, and the other end of which is rotatably connected to the front wheel assembly.

9. The frame steering structure according to claim 8, characterized in that: The rotation points of the universal connecting rod and the steering control component are staggered with the first hinge axis.

10. A vehicle frame steering structure according to any one of claims 1 to 3, characterized in that: A reinforcement assembly is provided on the chassis assembly, and the reinforcement assembly includes a connecting rod arranged in the chassis assembly.

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