Limiting method for metal joints in hinge device of low-floor vehicle

Abstract

The invention discloses a limiting method for a metal joint in a hinge device of a low-floor vehicle, and the limiting method comprises the step of limiting the transverse direction and the deflection direction of the metal joint, and the limiting method adopts a method of buffering first and then limiting to limit the transverse direction and the deflection direction. The mechanical property of the metal joint is further optimized, and the service life is prolonged.

Description

Technical Field

[0001] The invention relates to a limiting method, in particular to a limiting method for a metal joint in an articulated device of a low-floor vehicle, and belongs to the technical field of manufacturing articulated devices of low-floor vehicles. Background Art

[0002] Low-floor light rail vehicles, hereinafter referred to as low-floor vehicles, are new types of modern urban transportation equipment. They are generally composed of three, five or seven vehicles, connected by an articulated system, and the vehicle is less than 40 cm from the track surface. The vehicle body articulation device is an important part of the vehicle body connection of urban low-floor vehicles. At present, with the widespread application of low-floor vehicles in Europe, they are also being promoted in China, so the market demand for articulated devices is also increasing.

[0003] The body articulation device is arranged at the connecting parts at both ends of the body, generally adopting the cooperation mode of upper and lower hinge supports. Its main function is to connect multiple low-floor carriages, while meeting the vehicle's traction and braking force transmission requirements, and adapting to the needs of the vehicle passing through small-radius horizontal and vertical curves in urban traffic.

[0004] The metal joints of the low-floor vehicle articulation device are the core load-bearing components of the articulation device, and play the role of transmitting dynamic loads, such as longitudinal loads: transmitting traction and braking force, especially when starting on a slope or emergency braking, the metal joints need to withstand high load impact. Transverse loads: distribute centrifugal force when turning to avoid overloading of one side of the wheel. Vertical loads: cooperate with fixed hinges to support the weight of the suspension module to ensure the same height of the floor surface.

[0005] The metal joint needs to allow the vehicle to rotate around the vertical axis when turning (to adapt to small radius curves), while limiting excessive displacement to prevent rolling and nodding movements. Therefore, the limiting method of the metal joint needs to be designed.

[0006] A Chinese invention patent application with application publication number CN105822665A and application publication date August 3, 2016 discloses an integral metal joint bearing in a fixed hinge of a low-floor vehicle, comprising a metal joint outer seat sleeve, an outer rolling ball sleeve arranged inside the metal joint outer seat sleeve, an inner rolling ball arranged inside the outer rolling ball sleeve, and a wear-resistant bushing 1 arranged between the metal joint outer seat sleeve and the outer rolling ball sleeve: the inner rolling ball and the outer rolling ball sleeve as well as the outer rolling ball sleeve and the wear-resistant bushing 1 are all in spherical contact, and the metal joint outer seat sleeve, the outer rolling ball sleeve, the inner rolling ball and the wear-resistant bushing 1 are assembled into an integral metal joint bearing by screws.

[0007] The limiting method of the metal joint in the above patent document is different from the technical solution in this application.

[0008] In summary, how to design a limiting method for the metal joint in the articulated device of a low-floor vehicle, further optimize the mechanical properties of the product, and improve the service life is a technical problem that urgently needs to be solved. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a limiting method for the metal joint in the articulated device of a low-floor vehicle to address the defects in the prior art, further optimize the mechanical properties of the metal joint, and improve the service life.

[0010] To solve the above technical problem, the technical solution adopted by the present invention is: a limiting method for the metal joint in the articulated device of a low-floor vehicle, the limiting method includes limiting the lateral and deflection directions of the metal joint, and the limiting method limits the lateral and deflection directions by using a method of first buffering and then limiting.

[0011] Preferably, the metal joint includes an outer seat sleeve of the metal joint, an outer rolling ball sleeve arranged inside the outer seat sleeve of the metal joint, and an inner limiting block arranged inside the outer rolling ball sleeve. The opposite surfaces between the outer rolling ball sleeve and the inner limiting block are both set as mutually matching spherical surfaces. A wear-resistant ball sleeve I is vulcanized with rubber inside the outer seat sleeve of the metal joint. When the inner limiting block is locked on the outer seat sleeve of the metal joint through bolts so that the inner limiting block, the outer rolling ball sleeve, and the outer seat sleeve of the metal joint form a metal joint, the wear-resistant ball sleeve I is in spherical contact with the outer rolling ball sleeve; a wear-resistant ball sleeve II is arranged inside the outer rolling ball sleeve, and the opposite surfaces between the wear-resistant ball sleeve II and the inner limiting block are set as mutually matching spherical surfaces, and a gap H is left between the wear-resistant ball sleeve II and the inner limiting block; The method of first buffering and then limiting for lateral limiting means that during the working process, when a lateral force is received, the rubber first deforms to perform the first buffering, then the wear-resistant ball sleeve II is used for the second buffering, and finally the inner limiting block and the outer rolling ball sleeve are in indirect contact with each other for limiting.

[0012] Preferably, an upward-extending shaft column is further arranged on the inner spherical surface of the outer seat sleeve of the metal joint. The rubber includes a spherical rubber body, and the spherical rubber body is vulcanized and bonded between the inner spherical surface of the outer seat sleeve of the metal joint and the outer spherical surface of the wear-resistant ball sleeve I. One end of the spherical rubber body extends to form a sleeve-shaped rubber body, and the sleeve-shaped rubber body is used to wrap around the outer peripheral surface of the shaft column, and a radial distance K is left between the sleeve-shaped rubber body and the outer rolling ball sleeve; The method of first buffering and then limiting for deflection direction limiting means that during the working process, when the outer rolling ball sleeve deflects under the action of a force, during the process of the shaft column with the sleeve-shaped rubber body contacting the outer rolling ball sleeve, the sleeve-shaped rubber body first deforms to perform buffering, and then the shaft column and the outer rolling ball sleeve are in indirect contact with each other for limiting.

[0013] Preferably, one end of the spherical rubber body near the bottom of the shaft column is thickened with rubber, so that during the working process, the spacer sleeve can be buffered first and then limited.

[0014] Preferably, a first embedding groove is formed on the inner spherical surface of the outer rolling ball sleeve, and the wear-resistant ball sleeve II is embedded into the first embedding groove, so that the wear-resistant ball sleeve II is arranged on the inner spherical surface of the outer rolling ball sleeve.

[0015] Preferably, an annular step portion is arranged near the inner top of the outer rolling ball sleeve, an annular groove is arranged on the annular step portion, and a sealing ring is arranged in the annular groove; during assembly, by pressing the top plate against the annular step portion, the top plate is used to press against and contact the sealing ring to form a sealing structure.

[0016] Preferably, a second embedding groove is arranged on the side of the spacer sleeve closest to the outer rolling ball sleeve. During manufacturing, the spacer sleeve is first bonded to the outer seat sleeve of the metal joint by rubber vulcanization, and then the wear-resistant ball sleeve I is embedded into the second embedding groove on the spacer sleeve, so that the wear-resistant ball sleeve I is bonded to the inside of the outer seat sleeve of the metal joint by rubber vulcanization.

[0017] Preferably, an oil storage groove is arranged on the contact spherical surface between the wear-resistant ball sleeve I and the outer rolling ball sleeve, and lubricating grease is stored in the oil storage groove.

[0018] Preferably, the oil storage groove is arranged on the outer rolling ball sleeve.

[0019] Preferably, the oil storage groove is arranged on the wear-resistant ball sleeve I.

[0020] The beneficial effects of the present invention are as follows: through the structural design, the metal joint can be limited in the horizontal and deflection directions in a manner of buffering first and then limiting, thereby further optimizing the mechanical properties of the metal joint and increasing the service life. The rubber is set into a multi-layer split structure through multiple spacer sleeves, and the horizontal limit is carried out by the spherical contact between the wear-resistant ball sleeve I and the outer rolling ball sleeve. Such a design enables the metal joint to have a smaller deflection stiffness and torsional stiffness, so that the derivative stiffness of the vehicle body is smaller, and it can also ensure that the product has a larger vertical stiffness and radial stiffness, thereby further optimizing the mechanical properties of the product and increasing the service life. The inner limit block and the shaft column are installed through a stepped matching structure, and the further horizontal limit is carried out by the spherical contact between the wear-resistant ball sleeve II and the inner limit block, which can further improve the radial stiffness of the metal joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the axial sectional structure schematic diagram of the metal joint in Embodiment 1 of the present invention; Figure 2For Figure 1 Schematic enlarged structure diagram of part A in Figure 3 For Figure 1 Schematic enlarged structure diagram of part B in Figure 4 Axial sectional structure diagram of the articulated device of the low - floor vehicle in the embodiment of the present invention Figure 5 For Figure 1 Schematic enlarged structure diagram of part C in Figure 6 For Figure 1 Schematic enlarged structure diagram of part D in In the figure: 1. Outer seat sleeve of metal joint; 111. Axial column; 112. Step - shaped protruding part; 2. Outer rolling ball sleeve; 211. Annular step part; 212. Annular groove; 3. Inner limit block; 311. Step - shaped groove; 4. Rubber; 411. Spherical rubber body; 412. Sleeve - shaped rubber body; 5. Wear - resistant ball sleeve one; 6. Spacer sleeve; 7. Bolt; 8. Wear - resistant ball sleeve two; 9. Embedding groove one; 10. Metal joint; 11. Upper fixed support; 12. Lower fixed support; 13. Sealing ring; 14. Top plate; 15. Embedding groove two; 16. Oil storage tank. Specific embodiments

[0022] The technical solutions of the present invention will be further elaborated in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Embodiment: A method for limiting the position of a metal joint in an articulated device of a low - floor vehicle. The position - limiting method improves the lateral position - limiting and deflection - direction position - limiting of the metal joint, that is, a method of buffering first and then position - limiting is adopted for lateral and deflection - direction position - limiting.

[0024] The specific improvement method is as follows: As shown in Figure 1 and Figure 2 , the metal joint includes an outer seat sleeve 1 of the metal joint, an outer rolling ball sleeve 2 arranged inside the outer seat sleeve 1 of the metal joint, and an inner limit block 3 arranged inside the outer rolling ball sleeve 2. The opposite surfaces between the outer rolling ball sleeve 2 and the inner limit block 3 are both set to be mutually matching spherical surfaces. A wear - resistant ball sleeve one 5 is vulcanized by rubber 4 inside the outer seat sleeve 1 of the metal joint. When the inner limit block 3 is locked on the outer seat sleeve 1 of the metal joint through a bolt 7 so that the inner limit block 3, the outer rolling ball sleeve 2, and the outer seat sleeve 1 of the metal joint form a metal joint, the wear - resistant ball sleeve one 5 is in spherical contact with the outer rolling ball sleeve 2. As shown in Figure 1 and Figure 3As shown in the figure, an anti-wear ball sleeve II 8 is provided on the inner part of the outer rolling ball sleeve 2. The opposite surfaces between the anti-wear ball sleeve II 8 and the inner limit block 3 are set as mutually matching spherical surfaces. When the metal joint is in working conditions such as rotation or swing, a gap H is left between the anti-wear ball sleeve II 8 and the inner limit block 3. Multiple spacer sleeves 6 are provided in the rubber 4. The method of first buffering and then limiting for lateral limitation means that during the working process, when a lateral acting force is received, the rubber 4 first deforms to buffer, and then the anti-wear ball sleeve II 8 and the inner limit block 3 come into contact with each other for limitation. Here, the rubber 4 especially refers to the rubber located at the multiple spacer sleeves.

[0025] Both the anti-wear ball sleeve I 5 and the anti-wear ball sleeve II 8 can be made of wear-resistant materials such as polyester, copper-inlaid graphite, or PTFE. Here, since the anti-wear ball sleeve II 8 is not made of metal, during the limiting process, the anti-wear ball sleeve II 8 can also play the role of buffering again, that is, first buffer through the rubber 4 for the first time, then buffer again through the anti-wear ball sleeve II 8, and finally limit through the indirect contact between the inner limit block 3 and the outer rolling ball sleeve 2.

[0026] As Figure 1 shown in the figure, an upwardly extending shaft column 111 is further provided on the inner spherical surface of the outer seat sleeve 1 of the metal joint. The shaft column 111 and the outer seat sleeve 1 of the metal joint are of an integral structure. The rubber 4 includes a spherical rubber body 411. The spherical rubber body 411 is vulcanized and bonded between the inner spherical surface of the outer seat sleeve 1 of the metal joint and the outer spherical surface of the anti-wear ball sleeve I 5. One end of the spherical rubber body 411 extends to form a sleeve-shaped rubber body 412. The sleeve-shaped rubber body 412 is used to wrap around the outer peripheral surface of the shaft column 111. A radial spacing K is left between the sleeve-shaped rubber body 412 and the outer rolling ball sleeve 2. The method of first buffering and then limiting for deflection direction limitation means that during the working process, when the outer rolling ball sleeve 2 deflects under the action of a force, during the process of the shaft column 111 with the sleeve-shaped rubber body 412 coming into contact with the outer rolling ball sleeve 2, the sleeve-shaped rubber body 412 first deforms to buffer, and then the shaft column 111 and the outer rolling ball sleeve 2 come into indirect contact with each other for limitation.

[0027] In this embodiment, by designing the above structure, the metal joint can be limited in a way of first buffering and then limiting in the lateral and deflection directions, thereby further optimizing the mechanical properties of the metal joint and improving the service life.

[0028] In this embodiment, the rubber 4 is arranged in a multi-layer split structure through a multi-layer spacer sleeve, and the spherical contact between the wear-resistant ball sleeve I and the outer rolling ball sleeve is utilized. Such a design enables the metal joint to have a relatively small deflection stiffness and torsional stiffness, thereby having a relatively small derivative stiffness on the vehicle body. At the same time, it can ensure that the product has a relatively large vertical stiffness and radial stiffness, further optimizing the mechanical properties of the product and increasing its service life. The spacer sleeve 6 can be made of metal materials. In addition, when the metal joint is in working conditions such as rotation or swing, due to the arrangement of the rubber, flexible frictional contact can be achieved between the outer seat sleeve of the metal joint and the outer rolling ball sleeve, thus avoiding the occurrence of excessive wear problems and increasing the service life of the entire product. In addition, the rubber can also reduce the noise generated by the vehicle body and reduce vibration. In addition, in the patent documents mentioned in the background technology, when the product rotates or swings, whether it is a large-angle movement or a small-angle movement, it is borne by the friction pair formed between the wear-resistant bushing and the outer rolling ball sleeve. After a long working time, excessive wear is likely to occur, thereby reducing the service life of the product. In this embodiment, when the metal joint makes a small-angle rotation or swing, it is borne by the deformation of the rubber located between the wear-resistant ball sleeve I and the outer seat sleeve of the metal joint. At this time, the wear-resistant ball sleeve I and the outer rolling ball sleeve are relatively stationary. Only when the metal joint makes a large-angle rotation or swing and the acting force exceeds the static friction force between the wear-resistant ball sleeve I and the outer rolling ball sleeve, relative movement will occur between the wear-resistant ball sleeve I and the outer rolling ball sleeve to form a friction pair. At this time, the product movement is borne jointly by the rubber deformation and the friction pair, thus greatly increasing the service life of the product.

[0029] In addition, wrapping the shaft column with a sleeve-shaped rubber body can achieve the functions of rust prevention and corrosion prevention. Another function is to increase the overall volume of the rubber and the vulcanization bonding area between the rubber and the outer seat sleeve of the metal joint, thereby further increasing the overall strength of the rubber.

[0030] As Figure 1 shown, the rubber at one end of the spherical rubber body 411 near the bottom of the shaft column 111 is thickened, so that it can play a role of buffering first and then limiting the spacer sleeve during the working process.

[0031] A stepped protrusion 112 is provided at the top of the shaft column 111, and a stepped groove 311 matching the stepped protrusion 112 is provided on the bottom surface of the inner limit block 3. During installation, the inner limit block 3 is snapped onto the shaft column 111 of the outer seat sleeve of the metal joint through the cooperation and contact between the stepped protrusion 112 and the stepped groove 311. Then, the inner limit block 3 is locked onto the outer seat sleeve of the metal joint by bolts 7, so that the inner limit block 3, the second wear-resistant ball sleeve 8, the outer rolling ball sleeve 2, the first wear-resistant ball sleeve 5, and the outer seat sleeve 1 of the metal joint form a metal joint. When the metal joint is in working conditions such as traction or braking, the gap H becomes zero, and the spherical contact between the second wear-resistant ball sleeve 8 and the inner limit block 3 is used for further lateral limitation. In this embodiment, the inner limit block and the shaft column are installed through a stepped matching structure. When the spherical contact between the second wear-resistant ball sleeve and the inner limit block is used for further lateral limitation, the radial stiffness of the metal joint can be further improved.

[0032] As Figure 3 shown, an inlay groove one 9 is formed on the inner spherical surface of the outer rolling ball sleeve 2, and the second wear-resistant ball sleeve 8 is embedded into the inlay groove one 9, so that the second wear-resistant ball sleeve 8 is arranged on the inner spherical surface of the outer rolling ball sleeve 2. Such an embedded structure design facilitates the subsequent replacement of the second wear-resistant ball sleeve and reduces the maintenance cost.

[0033] As Figure 4 shown, the entire metal joint 10 further connects adjacent vehicle bodies through an upper fixing support 11 and a lower fixing support 12. The entire metal joint 10 is applied to a vehicle body hinging device, meeting the vertical, lateral, longitudinal, and large offset torsion angle composite loading conditions; the metal joint 10 automatically centers, and the spherical surfaces of the outer seat sleeve 1 of the metal joint, the first wear-resistant ball sleeve 5, the outer rolling ball sleeve 2, the second wear-resistant ball sleeve 8, and the inner limit block 3 are all co-centered, and the metal joint 10 can make three independent relative rotations around this center of the sphere.

[0034] As Figure 1 and Figure 5 shown, an annular step portion 211 is provided at the inner top of the outer rolling ball sleeve 2, an annular groove 212 is provided on the annular step portion 211, and a sealing ring 13 is provided in the annular groove 212; during assembly, by pressing the top plate 14 against the annular step portion 211, the sealing ring 13 is pressed and contacted by the top plate 14 to form a sealing structure, thereby further improving the sealing performance of the entire product. The top plate 14 can be made of materials such as nylon.

[0035] As Figure 1 and Figure 2As shown, an inlay groove two 15 is provided on the side of the spacer sleeve 6 of the layer closest to the outer rolling ball sleeve 2. During manufacturing, first, the spacer sleeve 6 is vulcanized and bonded to the outer seat sleeve 1 of the metal joint through the rubber 4, and then the wear-resistant ball sleeve one 5 is embedded into the inlay groove two 15 on the spacer sleeve 6, so that the wear-resistant ball sleeve one 5 is vulcanized and bonded to the inside of the outer seat sleeve 1 of the metal joint through the rubber 4. Here, if the wear-resistant ball sleeve one is directly vulcanized and bonded to the rubber one, due to the material characteristics between the two, the bonding effect between them will not be very good; in addition, since the wear-resistant ball sleeve one can be made of wear-resistant materials such as polyester, copper-inlaid graphite or PTFE, in order to ensure its bonding effect, it is also necessary to study and analyze the bonding performance of various materials, which is relatively complicated; in addition, if the wear-resistant ball sleeve one is vulcanized and bonded to the rubber one, it is not convenient to replace the subsequent wear-resistant ball sleeve one, increasing the maintenance cost. Therefore, in this embodiment, first, the spacer sleeve is vulcanized and bonded to the rubber one, and then the wear-resistant ball sleeve one is installed on the spacer sleeve by an embedded method, so that the influence of the material characteristics of the wear-resistant ball sleeve one on the bonding effect does not need to be considered, thus ensuring the installation effect of the wear-resistant ball sleeve one, reducing the manufacturing difficulty, and in subsequent maintenance, the wear-resistant ball sleeve one can be replaced conveniently and quickly, and the maintenance cost is also reduced.

[0036] As Figure 1 and Figure 6 shown, an oil storage groove 16 is provided on the contact spherical surface between the wear-resistant ball sleeve one 5 and the outer rolling ball sleeve 2. The oil storage groove 16 can be provided on the outer rolling ball sleeve 2 or, as in this embodiment, on the wear-resistant ball sleeve one 5. During operation, by storing lubricating grease in the oil storage groove 16, the wear degree during product operation can be reduced, and the lubrication effect can be further improved.

[0037] In summary, through the structural design of the present invention, the metal joint can be limited in the horizontal and deflection directions in a way of first buffering and then limiting, thereby further optimizing the mechanical properties of the metal joint and increasing the service life. By using multiple spacer sleeves to form the rubber into a multi-layer split structure and using the spherical contact between the wear-resistant ball sleeve one and the outer rolling ball sleeve for horizontal limiting, such a design enables the metal joint to have a smaller deflection stiffness and torsional stiffness, so that the derivative stiffness of the vehicle body is smaller, and it can also ensure that the product has a larger vertical stiffness and radial stiffness, thereby further optimizing the mechanical properties of the product and increasing the service life. The inner limiting block and the shaft column are installed through a stepped matching structure, and the spherical contact between the wear-resistant ball sleeve two and the inner limiting block is used for further horizontal limiting, which can further improve the radial stiffness of the metal joint.

[0038] The "plurality" mentioned in the embodiments refers to a quantity of "two or more". The above embodiments are only for illustrating the present invention and not for limiting the present invention. Those skilled in the relevant technical field can also make various changes or transformations without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the present invention, and the protection scope of the present invention should be defined by each claim.

Claims

1. A limiting method for a metal joint in a low-floor vehicle articulation device, the limiting method including limiting the lateral and deflection directions of the metal joint, characterized in that: The limiting method limits the lateral and deflection directions by first buffering and then limiting.

2. The limiting method according to claim 1, wherein: The metal joint includes an outer seat sleeve of the metal joint, an outer rolling ball sleeve arranged inside the outer seat sleeve of the metal joint, and an inner limiting block arranged inside the outer rolling ball sleeve. The opposite surfaces between the outer rolling ball sleeve and the inner limiting block are both set as mutually matching spherical surfaces. A wear-resistant ball sleeve I is vulcanized inside the outer seat sleeve of the metal joint with rubber. When the inner limiting block is locked on the outer seat sleeve of the metal joint through bolts so that the inner limiting block, the outer rolling ball sleeve, and the outer seat sleeve of the metal joint form a metal joint, the wear-resistant ball sleeve I is in spherical contact with the outer rolling ball sleeve; a wear-resistant ball sleeve II is arranged inside the outer rolling ball sleeve, and the opposite surfaces between the wear-resistant ball sleeve II and the inner limiting block are set as mutually matching spherical surfaces, and a gap H is left between the wear-resistant ball sleeve II and the inner limiting block; The method of first buffering and then limiting for lateral limiting means that during the working process, when a lateral force is applied, the rubber first deforms to conduct the first buffering, then the wear-resistant ball sleeve II is used for secondary buffering, and finally the limiting is carried out through the indirect contact between the inner limiting block and the outer rolling ball sleeve.

3. The limiting method according to claim 2, characterized in that: On the inner spherical surface of the outer seat sleeve of the metal joint, an upward-extending shaft column is also arranged. The rubber includes a spherical rubber body, and the spherical rubber body is vulcanized and bonded between the inner spherical surface of the outer seat sleeve of the metal joint and the outer spherical surface of the wear-resistant ball sleeve I. One end of the spherical rubber body extends to form a sleeve-shaped rubber body, and the sleeve-shaped rubber body is used to wrap around the outer peripheral surface of the shaft column, and a radial distance K is left between the sleeve-shaped rubber body and the outer rolling ball sleeve; The method of first buffering and then limiting for deflection direction limiting means that during the working process, when the outer rolling ball sleeve deflects under the action of a force, during the process of the shaft column with the sleeve-shaped rubber body contacting the outer rolling ball sleeve, the sleeve-shaped rubber body first deforms to conduct buffering, and then the limiting is carried out through the indirect contact between the shaft column and the outer rolling ball sleeve.

4. The limiting method according to claim 3, wherein: Thicken the rubber at one end of the spherical rubber body near the bottom of the shaft column.

5. The limiting method according to claim 3, characterized in that: An embedding groove I is opened on the inner spherical surface of the outer rolling ball sleeve, and the wear-resistant ball sleeve II is embedded into the embedding groove I, so that the wear-resistant ball sleeve II is arranged on the inner spherical surface of the outer rolling ball sleeve.

6. The limiting method according to claim 3, wherein: An annular step portion is arranged near the inner top of the outer rolling ball sleeve, an annular groove is arranged on the annular step portion, and a sealing ring is arranged in the annular groove; during assembly, by pressing the top plate against the annular step portion, the top plate is pressed against and contacts the sealing ring to form a sealing structure.

7. The limiting method according to any one of claims 1 to 6, characterized in that: An embedding groove II is arranged on the side of the innermost spacer sleeve close to the outer rolling ball sleeve. During manufacturing, first, the spacer sleeve is vulcanized and bonded to the outer seat sleeve of the metal joint with rubber, and then the wear-resistant ball sleeve I is embedded into the embedding groove II on the spacer sleeve, so that the wear-resistant ball sleeve I is vulcanized and bonded inside the outer seat sleeve of the metal joint through rubber.

8. The limiting method according to claim 7, characterized in that: An oil storage groove is arranged on the contact spherical surface between the wear-resistant ball sleeve I and the outer rolling ball sleeve, and lubricating grease is stored in the oil storage groove.

9. The limiting method according to claim 8, wherein: The oil storage groove is arranged on the outer rolling ball sleeve.

10. The limiting method according to claim 8, wherein: The oil storage groove is arranged on the wear-resistant ball sleeve I.

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