A device for measuring the three-dimensional centroid height of an automobile

Abstract

This application relates to the field of automotive detection technology, specifically a device for measuring the three-dimensional centroid height of an automobile, which includes a bearing flat plate and a number of anti-skid tubes installed on the bearing flat plate. A connecting plate is installed on the anti-skid tube, the bottom of the connecting plate is in the same plane as the bottom of the anti-skid tube, a hydraulic cylinder is arranged on the top of the connecting plate, and a support member for supporting the vehicle frame is installed on the telescopic rod of the hydraulic cylinder. By replacing the flexible support method of the original vehicle frame, suspension and wheels with the rigid support method of the vehicle frame, support member and hydraulic cylinder, this application fixes the distance between the vehicle frame and the bearing flat plate, reduces the offset of the three-dimensional centroid of the vehicle during roll, and significantly improves the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method.

Description

Technical Field

[0001] This application relates to the technical field of vehicle detection, and particularly to a device for measuring the three-dimensional centroid height of a vehicle. Background Art

[0002] The three-dimensional centroid height of a vehicle is generally measured by the roll method. Affected by the roll angle and the anti-skid tube, the suspension and tires below the vehicle will deform when the vehicle rolls, resulting in the deviation of the three-dimensional centroid height of the vehicle during rolling from the actual centroid height, making the accuracy of the existing vehicle three-dimensional centroid height measurement device not high. Summary of the Invention

[0003] Aiming at the deficiencies of the existing technology, this application provides a device for measuring the three-dimensional centroid height of a vehicle. By replacing the flexible support method of the original vehicle frame, suspension and wheels with the rigid support method of the frame, support members and hydraulic cylinders, the distance between the vehicle frame and the bearing plate is fixed, the offset of the three-dimensional centroid of the vehicle during rolling is reduced, and the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method is significantly improved.

[0004] The above application purpose of this application is achieved through the following technical solutions:

[0005] A device for measuring the three-dimensional centroid height of a vehicle, including a bearing plate and a plurality of anti-skid tubes installed on the bearing plate. A connecting plate is installed on the anti-skid tube, the bottom of the connecting plate is in the same plane as the bottom of the anti-skid tube, a hydraulic cylinder is arranged on the top of the connecting plate, and a support member for supporting the vehicle frame is installed on the telescopic rod of the hydraulic cylinder;

[0006] The bearing plate has a plurality of bearing areas, and weighing sensors are arranged in the bearing areas.

[0007] Optionally, the support member includes a connecting member, the connecting member is installed on the top of the telescopic rod of the hydraulic cylinder, the top of the telescopic rod of the hydraulic cylinder is located in the middle of the connecting member, and supporting members are installed at both ends of the support member.

[0008] Optionally, one side of the supporting member close to the anti-skid tube has a baffle.

[0009] Optionally, the included angle between the supporting member and the baffle is an acute angle, and the opening of the included angle between the supporting member and the baffle faces away from the anti-skid tube.

[0010] Optionally, one end of the connecting plate close to the anti-skid tube extends out of the anti-skid tube, and the anti-skid tube is located in the middle of the connecting plate.

[0011] Optionally, the hydraulic cylinder is slidably connected to the connecting plate, and the hydraulic cylinder can translate on the connecting plate.

[0012] Optionally, there is a telescopic support rod between the anti-skid pipe and the support member. The top of the telescopic support rod is fixed to the support member, the bottom of the telescopic support rod is slidably connected to the connecting plate, and the telescopic support rod can translate on the connecting plate.

[0013] Optionally, the telescopic support rod includes an outer sleeve and an inner support rod slidably connected inside the outer sleeve. One end of the inner support rod extends out of the outer sleeve and is fixedly connected to the support member;

[0014] A conical tube is arranged inside the outer sleeve. The inner diameter of the conical tube continuously decreases in the direction away from the support member. A number of balls are arranged inside the conical tube. One end of the inner support rod away from the support member penetrates through the conical tube, and the number of the balls is distributed on the outside of the inner support rod;

[0015] The telescopic support rod is located on the side of the hydraulic cylinder close to the anti-skid pipe.

[0016] Optionally, the telescopic support rod includes an outer sleeve and an inner support rod slidably connected inside the outer sleeve. One end of the inner support rod extends out of the outer sleeve and is fixedly connected to the support member;

[0017] A conical tube is arranged inside the outer sleeve. The inner diameter of the conical tube continuously increases in the direction away from the support member. A number of balls are arranged inside the conical tube. One end of the inner support rod away from the support member penetrates through the conical tube, and the number of the balls is distributed on the outside of the inner support rod;

[0018] The telescopic support rod is located on the side of the hydraulic cylinder away from the anti-skid pipe.

[0019] In summary, the present application has the following beneficial technical effects:

[0020] By replacing the flexible support method of the original vehicle frame, suspension and wheels with the rigid support method of the frame, support member and hydraulic cylinder, the distance between the vehicle frame and the bearing plate is fixed. Also, through the setting of the load cells in the bearing area, the operator can determine the tilt angle of the bearing plate according to the pressure of the vehicle wheels on the load cells, avoiding vehicle rollover or one-side wheel suspension, reducing the offset of the three-dimensional centroid of the vehicle during rollover, and significantly improving the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the front view schematic diagram of an embodiment of the present application;

[0022] Figure 2 is the installation schematic diagram of the telescopic support rod of an embodiment of the present application;

[0023] Figure 3It is a schematic cross-sectional view of a telescopic support rod according to an embodiment of the present application;

[0024] Figure 4 Installation schematic diagram of a telescopic support rod according to an embodiment of the present application;

[0025] Figure 5 Schematic cross-sectional view of a telescopic support rod according to an embodiment of the present application.

[0026] Reference numerals: 10, bearing plate; 11, bearing area; 12, load cell;

[0027] 20, anti-skid tube;

[0028] 30, connecting plate; 31, hydraulic cylinder; 32, support member; 33, connecting member; 34, supporting member; 35, baffle;

[0029] 40, telescopic support rod; 41, outer sleeve; 42, inner support rod; 43, conical tube; 44, ball. Detailed implementation manners

[0030] The present application will be further described in detail below with reference to the accompanying drawings.

[0031] In order to more clearly understand the technical solutions provided by the embodiments of the present application, first, a brief introduction to an existing method and device for measuring the three-dimensional centroid height of an automobile is given.

[0032] An existing device for measuring the three-dimensional centroid height of an automobile generally consists of a base and a bearing plate that is adjustable relative to the base at a lower position. The three-dimensional centroid height of the vehicle is measured by the roll method. When measuring the three-dimensional centroid height of the automobile, first move the vehicle onto the bearing plate, and the operator gradually increases the angle between the bearing plate and the base until there is no contact pressure between the tire on one side of the vehicle and the bearing plate, and then stop. According to the angle α between the bearing plate and the base and the wheelbase l of the vehicle at this time, the three-dimensional centroid height h of the vehicle can be calculated, and the calculation is carried out according to the following formula:

[0033]

[0034] Under ideal conditions, when the lifting angle of the bearing plate can just make the pressure between the tire on one side of the vehicle and the bearing plate zero, and the wheelbase of the vehicle is measured accurately, relatively accurate data of the three-dimensional centroid height of the vehicle can be obtained.

[0035] However, in reality, as the angle between the supporting plate and the base increases, the vehicle is in a tilted state, and the side at the bottom (hereinafter for the sake of ease of description and understanding, the side at the top when the vehicle is rolling is defined as the first side, and the side at the bottom when the vehicle is rolling is defined as the second side) The vehicle suspension and tires are under stress, the travel of the vehicle suspension is compressed, and the tires are also compressed. At this time, the anti-skid tube squeezes the tires on the second side of the vehicle, increasing the variables, which is difficult to compensate and eliminate by calculation. This also results in the measurement of the three-dimensional center of mass height of the vehicle using the roll method. The measured three-dimensional center of mass height of the vehicle deviates from the actual three-dimensional center of mass height of the vehicle, that is, the accuracy of the device in the prior art using the roll method to measure the three-dimensional center of mass height of the vehicle is low.

[0036] In order to solve the above technical problems, refer to Figure 1 The embodiment of the present application provides a device for measuring the three-dimensional centroid height of an automobile, comprising a bearing plate 10 and a plurality of anti-skid tubes 20 mounted on the bearing plate 10.

[0037] A connecting plate 30 is installed on the anti-skid tube 20, the bottom of the connecting plate 30 is in the same plane as the bottom of the anti-skid tube 20, a hydraulic cylinder 31 is arranged on the top of the connecting plate 30, and a support member 32 for supporting the frame is installed on the telescopic rod of the hydraulic cylinder 31;

[0038] The carrying plate 10 has a plurality of carrying areas 11 , and weighing sensors 12 are disposed in the carrying areas 11 .

[0039] The following is a brief introduction based on specific usage scenarios.

[0040] When in use, the operator moves the vehicle onto the loading plate 10, ensuring that each wheel is respectively on the weighing sensor 12 of the loading area 11, and then the operator starts the hydraulic cylinder 31, the telescopic rod of the hydraulic cylinder 31 rises, and the support member 32 at the top thereof will support the frame of the vehicle, so that the distance between the vehicle frame and the upper surface of the loading plate 10 is fixed.

[0041] If the tilting method without using the technical solution provided in the embodiment of the present application is used as a comparative example, in the comparative example, the components actually supporting the vehicle are a combination of the frame, suspension and wheels. Thus, when the angle of the supporting plate 10 is raised and the vehicle tilts, the suspension and tires on the first side of the vehicle are bound to be compressed, which will cause the measured three-dimensional center of mass height to be inconsistent with the actual three-dimensional center of mass height; whereas in the embodiment of the present application, the components actually supporting the vehicle are the frame, the bearing member and the hydraulic cylinder 31, and the entire supporting component is rigid. Thus, when the vehicle tilts, the three-dimensional center of mass of the vehicle will not be offset due to the compression of the vehicle suspension and tires.

[0042] The operator controls the continuous tilting of the bearing plate 10. As the bearing plate 10 tilts, the vehicle thereon will also roll over. When the pressure of a number of wheels on the second side of the vehicle on the weighing sensors 12 in a number of bearing areas 11 on this side becomes zero, stop raising the angle of the bearing plate 10. The operator records the angle between the bearing plate 10 and the horizontal plane at this time to calculate the three-dimensional centroid height of the vehicle.

[0043] In the comparative example, generally, the angle of the bearing plate 10 is increased in stages, and the increase in the angle between the bearing plate 10 and the horizontal plane is stopped when the wheels on the second side of the vehicle leave the bearing plate 10. In this case, since the wheels on the second side of the vehicle leave the bearing plate 10, the actual roll angle of the vehicle is not equal to the angle between the bearing plate 10 and the horizontal plane, which leads to the deviation of the three-dimensional centroid of the vehicle. In the embodiment of the present application, through the setting of the bearing area 11 and the weighing sensors 12 in the bearing area 11, the operator can obtain the data of the weighing sensors 12 to real-time control the pressure of the wheels on the first side of the vehicle on the bearing plate 10. When the pressure of the wheels on the second side of the vehicle on the plate is zero, the operator can stop raising the angle between the bearing plate 10 and the horizontal plane, avoiding the suspension of the wheels on the second side of the vehicle, which may cause the vehicle to roll over and affect the measurement of the three-dimensional centroid position of the vehicle.

[0044] Generally speaking, in the embodiment of the present application, the flexible support method of the original vehicle frame, suspension and wheels is replaced by the rigid support method of the vehicle frame, the support member 32 and the hydraulic cylinder 31, fixing the distance between the vehicle frame and the bearing plate 10. And through the setting of the weighing sensors 12 in the bearing area 11, the operator can determine the tilting angle of the bearing plate 10 according to the pressure of the vehicle wheels on the weighing sensors 12, avoiding the vehicle rollover or the suspension of one side of the wheels, reducing the deviation amount of the three-dimensional centroid of the vehicle during rollover, and significantly improving the accuracy of measuring the three-dimensional centroid of the vehicle by the rollover method.

[0045] It can be noted that in the embodiment of the present application, the hydraulic cylinder 31 and the support member 32 support the vehicle to be measured. The hydraulic cylinder 31 is far away from the anti-skid tube 20 through the connecting plate 30. Since the position of the anti-skid tube 20 is fixed, the relative position of the vehicle during rollover is fixed by the support member 32 and the hydraulic cylinder 31, preventing the vehicle from further sliding down to the first side. During the whole measurement period, the anti-skid tube 20 does not contact the wheels of the vehicle, thus avoiding the situation that the anti-skid tube 20 squeezes the vehicle tires and causes the deviation of the three-dimensional centroid of the vehicle from the actual situation.

[0046] In some possible implementation manners of the embodiment of the present application, the anti-skid tube 20 can be installed and fixed in position through an iron chain and a number of ring bodies provided on the bearing plate 10.

[0047] As a feasible specific implementation manner of an embodiment of the present application, the support member 32 includes a connecting member 33, the connecting member 33 is installed at the top of the telescopic rod of the hydraulic cylinder 31, the top of the telescopic rod of the hydraulic cylinder 31 is located in the middle of the connecting member 33, and support members 34 for supporting the vehicle frame are installed at both ends of the support member 32.

[0048] Combined with a specific usage scenario, when the vehicle reaches the specified measurement location, the operator raises the hydraulic cylinder 31, so that the support members 34 at both ends of the connecting member 33 raise to support the vehicle frames on both sides. In this way, the vehicle frames on both sides rise at the same speed simultaneously, completing the rigid fixation of the position between the vehicle and the loading plate 10. The method of supporting the vehicle on both sides simultaneously can significantly improve the stability of the vehicle during fixation, further reduce the offset amount when the vehicle rolls over, and further improve the accuracy of measuring the three-dimensional centroid height of the vehicle.

[0049] In some possible implementation manners of an embodiment of the present application, the support member 34 may be in a concave shape, that is, there is a through groove in the middle of the top of the support member 34 for accommodating the vehicle frame. As the hydraulic cylinder 31 rises, the support member 34 with a concave cross-section contacts the vehicle frame, and the vehicle frame is embedded in the groove at the top of the support member 34. In this way, the support member 34 locks the vehicle frame in a rigid contact and restriction manner.

[0050] In some possible implementation manners of an embodiment of the present application, a baffle 35 is provided on one side of the support member 34 close to the anti-skid tube 20, that is, a baffle 35 for blocking the vehicle frame is provided on one side of the support member 34 close to the first side of the vehicle. In this way, when the vehicle has a tendency to slide towards the first side when rolling over, the baffle 35 can block the vehicle. While preventing the vehicle from sliding out of the loading plate 10 when rolling over, it also enables the vehicle to be fixed in position without contacting the anti-skid tube 20, avoiding the extrusion of the vehicle tires by the anti-skid tube 20, reducing the offset amount of the vehicle when measuring the three-dimensional centroid height, and improving the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method.

[0051] In some possible implementation manners of an embodiment of the present application, the included angle between the support member 34 and the baffle 35 is an acute angle, and the opening of the included angle between the support member 34 and the baffle 35 faces away from the anti-skid tube 20. In this way, when the loading plate 10 rolls over, the vehicle on its top will slide downwards, and its frame will enter the included angle between the support member 34 and the baffle 35, thereby rigidly restricting the position of the vehicle. While preventing the vehicle from sliding out of the loading plate 10 when rolling over, it also enables the vehicle to be fixed in position without contacting the anti-skid tube 20, avoiding the extrusion of the vehicle tires by the anti-skid tube 20, reducing the offset amount of the vehicle when measuring the three-dimensional centroid height, and improving the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method.

[0052] As a feasible specific implementation manner of an embodiment of the present application, one end of the connecting plate 30 close to the anti-skid tube 20 extends out of the anti-skid tube 20, and the anti-skid tube 20 is located in the middle of the connecting plate 30. In this way, when the anti-skid tube 20 has a tendency to turn over downward, the end of the connecting plate 30 extending out of the anti-skid tube 20 will closely adhere to the bearing plate 10, preventing the anti-skid tube 20 from turning over downward, ensuring the relative positions of the hydraulic cylinder 31 and the bearing member, reducing the offset of the three-dimensional centroid height of the vehicle measured, and improving the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method.

[0053] As a feasible specific implementation manner of an embodiment of the present application, the hydraulic cylinder 31 is slidably connected to the connecting plate 30, and the hydraulic cylinder 31 can translate on the connecting plate 30. By translating the hydraulic cylinder 31, the hydraulic cylinder 31 is in a suitable supporting position, ensuring that the supporting member 32 at the top of the hydraulic cylinder 31 presses against the vehicle frame before the vehicle rolls. Before the roll starts, the operator can lock the position of the hydraulic cylinder 31 by means of bolt locking. In this way, the position of the vehicle is fixed when it rolls, avoiding the offset of the three-dimensional centroid height caused by the vehicle movement, and improving the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method.

[0054] As a feasible specific implementation manner of an embodiment of the present application, referring to Figure 2 , there is a telescopic support rod 40 for fixing the height of the support member 32 between the anti-skid tube 20 and the support member 32. The top of the telescopic support rod 40 is fixed to the support member 32, and the bottom of the telescopic support rod 40 is slidably connected to the connecting plate 30. The telescopic support rod 40 can translate on the connecting plate 30. By fixing the distance between the support member 32 and the connecting plate 30, the support member 32 is fixed, thereby reducing the possible offset when the vehicle rolls and improving the accuracy of measuring the three-dimensional centroid of the vehicle by the roll method.

[0055] In some possible implementation manners of an embodiment of the present application, referring to Figure 2 and Figure 3, the telescopic support rod 40 is located on the side of the hydraulic cylinder 31 close to the anti-skid tube 20. The telescopic support rod 40 includes an outer sleeve 41 and an inner support rod 42 slidably connected inside the outer sleeve 41. One end of the inner support rod 42 extends out of the outer sleeve 41 and is fixedly connected to the support member 32. A tapered cylinder 43 is arranged inside the outer sleeve 41. The inner diameter of the tapered cylinder 43 continuously decreases in the direction away from the support member 32. A number of balls 44 are arranged inside the tapered cylinder 43. One end of the inner support rod 42 away from the support member 32 penetrates through the tapered cylinder 43. The number of balls 44 are distributed on the outside of the inner support rod 42. After the telescopic rod of the hydraulic cylinder 31 extends out completely, with the tilting of the bearing platform, the connecting plate 30 on the first side is under the pressure of the vehicle and has a tendency to approach the bearing plate 10. Since the inner support rod 42 of the telescopic support rod 40 is fixedly connected to the connecting member 33, when the connecting member 33 applies pressure to the inner support rod 42, a number of balls 44 inside the tapered cylinder 43 of the outer sleeve 41 simultaneously have a tendency to move downward. However, restricted by the tapered cylinder 43, the balls 44 will prevent the inner support rod 42 from sinking, fixing the relative position of the inner support rod 42, and thus fixing the position of the connecting member 33, avoiding the connecting member 33 from approaching the bearing plate 10. In this way, the offset amount of the three-dimensional centroid height measurement of the vehicle is reduced, and the accuracy of measuring the three-dimensional centroid of the vehicle by the tilting method is improved. After the measurement is completed, the operator can unlock the inner support rod 42 by removing the balls 44.

[0056] In some possible implementation manners of the embodiments of the present application, with reference to Figure 4 and Figure 5, the telescopic support rod 40 is located on the side of the hydraulic cylinder 31 away from the anti-skid tube 20. The telescopic support rod 40 includes an outer sleeve 41 and an inner support rod 42 slidably connected inside the outer sleeve 41. One end of the inner support rod 42 extends out of the outer sleeve 41 and is fixedly connected to the support member 32. A tapered cylinder 43 is provided inside the outer sleeve 41. The inner diameter of the tapered cylinder 43 continuously increases in the direction away from the support member 32. A number of balls 44 are provided inside the tapered cylinder 43. One end of the inner support rod 42 away from the support member 32 penetrates through the tapered cylinder 43. The number of balls 44 is distributed on the outside of the inner support rod 42. After the telescopic rod of the hydraulic cylinder 31 extends out completely, with the tilting of the load platform, the connecting plate 30 on the second side is under the pressure of the vehicle and has a tendency to move away from the load flat plate 10. Since the inner support rod 42 of the telescopic support rod 40 is fixedly connected to the connecting member 33, when the connecting member 33 applies pressure to the inner support rod 42, a number of balls 44 inside the tapered cylinder 43 of the outer sleeve 41 simultaneously have an upward movement tendency. However, restricted by the tapered cylinder 43, the balls 44 will prevent the inner support rod 42 from moving upward, fixing the relative position of the inner support rod 42, thereby fixing the position of the connecting member 33 and preventing the connecting member 33 from moving away from the load flat plate 10. In this way, the offset of the three-dimensional centroid height of the vehicle during measurement is reduced, and the accuracy of measuring the three-dimensional centroid of the vehicle by the tilting method is improved. Before the measurement starts, that is, before the telescopic rod of the hydraulic cylinder 31 rises, the operator can release the lock on the inner support rod 42 by temporarily removing the balls 44 and reset the balls 44 after the telescopic rod of the hydraulic cylinder 31 rises to a fixed height to fix the position of the inner support rod 42.

[0057] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A device for measuring the three-dimensional centroid height of an automobile, comprising a bearing flat plate (10) and a plurality of anti-skid pipes (20) mounted on the bearing flat plate (10). Characterized in that, A connecting plate (30) is mounted on the anti-skid pipe (20), the bottom of the connecting plate (30) is in the same plane as the bottom of the anti-skid pipe (20), a hydraulic cylinder (31) is arranged on the top of the connecting plate (30), and a support member (32) for supporting the vehicle frame is mounted on the telescopic rod of the hydraulic cylinder (31). The bearing flat plate (10) has a plurality of bearing areas (11), and load cells (12) are arranged in the bearing areas (11). The support member (32) includes a connecting member (33), the connecting member (33) is mounted on the top of the telescopic rod of the hydraulic cylinder (31), and support members (34) are mounted at both ends of the support member (32). One side of the support member (34) close to the anti-skid pipe (20) has a baffle (35). The included angle between the support member (34) and the baffle (35) is an acute angle, and the opening of the included angle between the support member (34) and the baffle (35) faces away from the anti-skid pipe (20). One end of the connecting plate (30) close to the anti-skid pipe (20) extends out of the anti-skid pipe (20), and the anti-skid pipe (20) is located in the middle of the connecting plate (30).

2. A device for measuring the three-dimensional centroid height of an automobile according to claim 1, Characterized in that, The hydraulic cylinder (31) is slidably connected to the connecting plate (30), and the hydraulic cylinder (31) can translate on the connecting plate (30).

3. A device for measuring the three-dimensional centroid height of an automobile according to claim 2, Characterized in that, There is a telescopic support rod (40) between the anti-skid pipe (20) and the support member (32), the top of the telescopic support rod (40) is fixed on the support member (32), the bottom of the telescopic support rod (40) is slidably connected to the connecting plate (30), and the telescopic support rod (40) can translate on the connecting plate (30).

4. A device for measuring the three-dimensional centroid height of an automobile according to claim 3, Characterized in that, The telescopic support rod (40) includes an outer sleeve (41) and an inner support rod (42) slidably connected inside the outer sleeve (41), and one end of the inner support rod (42) extends out of the outer sleeve (41) and is fixedly connected to the support member (32). A conical cylinder (43) is arranged inside the outer sleeve (41), the inner diameter of the conical cylinder (43) continuously decreases in the direction away from the support member (32), a plurality of balls (44) are arranged inside the conical cylinder (43), and one end of the inner support rod (42) away from the support member (32) penetrates through the conical cylinder (43), and the plurality of balls (44) are distributed on the outer side of the inner support rod (42). The telescopic support rod (40) is located on the side of the hydraulic cylinder (31) close to the anti-skid pipe (20).

5. A device for measuring the three-dimensional centroid height of an automobile according to claim 3, Characterized in that, The telescopic support rod (40) includes an outer sleeve (41) and an inner support rod (42) slidably connected inside the outer sleeve (41). One end of the inner support rod (42) extends out of the outer sleeve (41) and is fixedly connected to the support member (32). A conical tube (43) is provided inside the outer sleeve (41). The inner diameter of the conical tube (43) continuously increases in the direction away from the support member (32). A number of balls (44) are provided inside the conical tube (43). One end of the inner support rod (42) away from the support member (32) penetrates through the conical tube (43), and the number of the balls (44) is distributed on the outer side of the inner support rod (42). The telescopic support rod (40) is located on the side of the hydraulic cylinder (31) away from the anti-skid tube (20).

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