Pre-compressed air spring and assembling method

Abstract

The invention relates to a pre-compressed air spring and an assembling method. The air spring comprises an upper cover, a cylinder barrel, an air bag and a conical rubber pile. Wherein the air bag is hermetically connected with the upper cover and the cylinder barrel respectively; a conical rubber pile and a sleeve are arranged in the cylinder barrel; the conical rubber-metal pad comprises a rubber-metal pad mandrel and a rubber-metal pad jacket; the rubber-metal pad outer sleeve is sleeved outside the rubber-metal pad core shaft; a central hole is formed in the bottom wall of the rubber reactor mandrel; the sleeve penetrates through the central hole and is fixedly connected with the cylinder barrel; when the air spring is in an air-free state, the conical rubber pile bears pressure to enable the rubber pile mandrel and the sleeve to move relatively, the center hole is separated from the sleeve, and the conical rubber pile bears load and deformation. The conical rubber pile is arranged in the cylinder barrel and is pre-compressed, so that the overall height of the conical rubber pile is reduced on the premise of ensuring the vertical rigidity of the conical rubber pile, the internal space of the cylinder barrel is fully utilized, and the damping effect of the air spring in an airless state is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of rail transit, and particularly relates to a pre-compressed air spring and an assembly method thereof. Background Art

[0002] In rail vehicles such as low-floor trams, the air spring, as a key component, is usually installed between the car body and the bogie, and has the functions of buffering and vibration reduction, which can effectively improve the running smoothness and riding comfort of the vehicle and reduce the impact on each component of the vehicle.

[0003] Based on the inherent characteristics of the low-floor design, the available installation space between the car body and the bogie is extremely limited. This requires that the air spring has a lower installation height and a smaller outer diameter on the basis of maintaining the original vertical and lateral vibration reduction performance to adapt to the compact installation environment.

[0004] In the prior art, due to the limited overall volume of the air spring, a cylinder or a similar metal structure is usually directly installed under the airbag. Moreover, in order to prevent the upper cover from directly contacting and rubbing against the cylinder in the airless state of the air spring, a flat conical rubber stack is installed in the cylinder to achieve further buffering and support. However, due to the relatively large vertical stiffness of the flat conical rubber stack, the vibration reduction effect of the air spring in the airless state is not ideal and cannot effectively meet the smooth running requirements of the vehicle under various working conditions. Summary of the Invention

[0005] The purpose of the present invention is to solve one of the above technical problems, and provide a pre-compressed air spring and an assembly method thereof.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A pre-compressed air spring, comprising: an upper cover, a cylinder, an airbag and a conical rubber stack;

[0008] The upper and lower mouths of the airbag are respectively sealed and connected to the upper cover and the cylinder;

[0009] A conical rubber stack and a sleeve are arranged in the cylinder;

[0010] The conical rubber stack includes a rubber stack core shaft and a rubber stack outer sleeve; the rubber stack outer sleeve is sleeved outside the rubber stack core shaft; a central hole is opened on the bottom wall of the rubber stack core shaft;

[0011] The sleeve penetrates through the central hole and is fixedly connected to the cylinder;

[0012] When the air spring is in the inflated state, the central hole is in contact with and connected to the sleeve, and the compressed gas inside the airbag bears the load and deformation; when the air spring is in the deflated state, the conical rubber stack bears the pressure, causing relative movement between the rubber stack core shaft and the sleeve, separating the central hole from the sleeve, forming a predetermined gap both horizontally and vertically, and the conical rubber stack bears the load and deformation.

[0013] In some embodiments of the present invention, rubber protrusions are provided at the bottom of the conical rubber stack; when the air spring is deflated and under heavy load, the rubber protrusions are in contact with the upper surface of the base.

[0014] In some embodiments of the present invention, the corresponding stiffness of the conical rubber stack body is K 1 , and the corresponding stiffness of the rubber protrusions is K 2 ; the combined stiffness of the conical rubber stack body and the rubber protrusions is K:

[0015] K = K 1 *K 2 / (K 1 +K 2 ).

[0016] In some embodiments of the present invention, a conical surface is provided in the central hole, and the sleeve is provided with a conical section that matches the conical surface. During the process of the central hole coming into contact with the sleeve, automatic centering is achieved through the cooperation of the conical surface and the conical section.

[0017] In some embodiments of the present invention, a gasket is provided between the rubber stack outer sleeve and the cylinder barrel. The gasket is used to adjust the compression amount of the conical rubber stack, and the number of gaskets is positively correlated with the magnitude of the pre-pressure of the conical rubber stack.

[0018] In some embodiments of the present invention, a friction block is fixed to the top of the rubber stack core shaft. When the air spring is in the deflated state, the upper cover is in contact with and connected to the friction block.

[0019] In some embodiments of the present invention, after the central hole is separated from the sleeve, the horizontal predetermined gap is Dx0;

[0020] When the air spring is in the deflated state and the upper cover is subjected to a horizontal force, after the upper cover and the friction block have translated a predetermined distance, relative sliding occurs. The predetermined distance is Dx1, and Dx1 is less than Dx0.

[0021] In some embodiments of the present invention, the torsional angle range of the upper cover relative to the horizontal plane is from -α to α. When the upper cover is twisted within the range of -α to α, the central hole remains separated from the sleeve.

[0022] In some embodiments of the present invention, a flat support is further provided inside the cylinder barrel. The support is located below the conical rubber stack and is fixedly connected to the cylinder barrel; the end of the sleeve extending out of the rubber stack core shaft is connected to the support.

[0023] Some embodiments of the present invention further provide a method for assembling a pre-compressed air spring for assembling the above-mentioned pre-compressed air spring, including the following steps:

[0024] Place the base and the conical rubber stack in the cylinder in sequence;

[0025] Insert the sleeve into the central hole at the bottom of the rubber stack core shaft;

[0026] Apply pressure to the conical rubber stack using a preloading tooling, so that the central hole at the bottom of the rubber stack core shaft is separated from the sleeve;

[0027] Adjust the sleeve to a predetermined height using an adjustment tooling and then fixedly connect it to the cylinder;

[0028] Release the pressure of the preloading tooling on the conical rubber stack, so that the upper surface of the central hole at the bottom of the rubber stack core shaft contacts and is pressed by the sleeve;

[0029] Place the airbag in the center on the cylinder, and make the lower sub-mouth of the airbag be sealingly connected to the cylinder;

[0030] Place the upper cover in the center on the airbag, and make the upper sub-mouth of the airbag be sealingly connected to the upper cover.

[0031] The beneficial effects of the present invention are as follows:

[0032] 1. In the present invention, the rubber stack inside the cylinder is designed in a conical shape and pre-compressed. On the premise of ensuring the vertical stiffness of the conical rubber stack, the overall height of the conical rubber stack is reduced, making full use of the internal space of the cylinder. The overall structure is simple and compact, and is convenient for maintenance;

[0033] 2. In the present invention, a central hole is opened at the bottom of the rubber stack core shaft, and a sleeve is arranged therein. In the state where the air spring has no air, the rubber stack core shaft and the sleeve move relative to each other and separate, forming a predetermined gap both horizontally and vertically, so that the air spring realizes free deformation in the vertical, horizontal and torsional directions to a certain extent;

[0034] 3. In the present invention, the inner surface of the central hole is designed as a conical surface, and a conical section is arranged on the sleeve to cooperate with it. During the contact process between the central hole and the sleeve, under the cooperation of the conical surface and the conical section, the rubber stack core shaft can be aligned to the central position to achieve automatic centering;

[0035] 4. In the present invention, rubber protrusions are designed at the bottom of the conical rubber stack, reducing the stiffness of the conical rubber stack in the state of no air and heavy load, and avoiding the sudden increase in the stiffness of the conical rubber stack, which affects the riding comfort of the rail vehicle.

[0036] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the structure particularly pointed out in the specification, claims as well as the drawings. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the specific embodiments of the present invention will be described in detail below with reference to the drawings. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic structural diagram of a pre-compressed air spring;

[0039] Figure 2 It is a schematic structural diagram of a cylinder barrel and a conical rubber stack;

[0040] Figure 3 It is a schematic structural diagram of an upper cover, a conical rubber stack and a sleeve in a non-air state;

[0041] Figure 4 It is a schematic structural diagram of the upper cover moving horizontally by a distance Dx2 in a non-air state;

[0042] Figure 5 It is a schematic structural diagram of the upper cover rotating by an angle α in a non-air state;

[0043] Figure 6 It is a schematic structural diagram of a rubber protrusion contacting a support in a non-air and heavy-load state;

[0044] Figure 7 It is a schematic cross-sectional diagram of the mating relationship between a preloading tooling and an adjusting tooling;

[0045] Figure 8 It is a schematic structural diagram of the mating relationship between a preloading tooling and an adjusting tooling;

[0046] Among them, the reference numerals are:

[0047] 1. Upper cover; 2. Airbag; 3. Cylinder barrel; 31. Bottom pin; 4. Conical rubber stack; 41. Rubber stack core shaft; 411. Central hole; 42. Rubber stack outer sleeve; 43. Rubber protrusion; 5. Sleeve; 6. Fastener; 7. Gasket; 8. Friction block; 9. Support; 10. O-ring; 11. Preloading tooling; 12. Extension rod; 13. Torque wrench. Detailed Embodiments

[0048] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be described and explained below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments provided in the present application without making creative efforts fall within the scope of protection of the present application.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0050] In the case of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0051] The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments and the accompanying drawings of the specification.

[0052] As shown in the attached Figure 1 - attached Figure 6 As shown, in a schematic embodiment of a pre-compressed air spring of the present invention, the air spring includes an upper cover 1, a cylinder barrel 3, an airbag 2 and a conical rubber stack 4.

[0053] Among them, both the upper cover 1 and the cylinder barrel 3 are provided with mating surfaces for mating connection with the airbag 2. The upper and lower mouths of the airbag 2 are in interference fit with the upper cover 1 and the cylinder barrel 3 respectively to achieve sealed connection, and further achieve sealing of the pressure gas inside the air spring.

[0054] The upper cover 1 is connected to the vehicle body, and is sealed between the upper cover 1 and the vehicle body through an O-ring to prevent air leakage.

[0055] The cylinder barrel 3 is connected to the bogie. A bottom pin 31 is provided at the bottom of the cylinder barrel 3, and a pin hole mating with the bottom pin 31 is provided on the bogie. The bottom pin 31 is inserted into the pin hole to mate with the bogie for connection, so as to realize the installation and positioning of the cylinder barrel 3.

[0056] The cylinder barrel 3 is also provided with a semi-open cavity with an upward opening in the sealed space formed with the upper cover 1 and the airbag 2. A conical rubber stack 4 and a sleeve 5 are provided in the semi-open cavity of the cylinder barrel 3.

[0057] The conical rubber stack 4 is used to achieve the buffering and vibration damping functions of the air spring in the non-air state. Compared with other types of rubber stacks, its vertical stiffness and lateral deformation are more in line with the usage requirements, and it includes a rubber stack core shaft 41 and a rubber stack outer sleeve 42.

[0058] Among them, the rubber stack outer sleeve 42 is sleeved outside the rubber stack core shaft 41, and its outer wall is in contact connection with the inner side wall of the cylinder barrel 3.

[0059] The cross-section of the rubber stack core shaft 41 in the vertical direction is arranged in a U shape, and a central hole 411 is opened on its bottom wall.

[0060] The sleeve 5 passes through the central hole 411 and is fixedly connected to the cylinder barrel 3 through a fastener 6.

[0061] The outer diameter of one end of the sleeve 5 located inside the rubber stack core shaft 41 is larger than the diameter of the central hole 411 for limiting to prevent the sleeve 5 from disengaging from the rubber stack core shaft 41. The outer diameter of the end of the sleeve 5 extending out of the rubber stack core shaft 41 is smaller than the diameter of the central hole 411, which is convenient for the sleeve 5 to be inserted into the central hole 411 from top to bottom.

[0062] A layer of PTFE is coated on the outer surface of the sleeve 5 to reduce friction, reduce wear, and prevent the rubber stack core shaft 41 from being accidentally stuck when the conical rubber stack 4 rebounds.

[0063] During the installation process of the conical rubber stack 4, pre-compression is carried out to reduce the overall height of the air spring. Moreover, the pre-pressure F1 of the conical rubber stack 4 is less than the unloaded weight Fz0 of the vehicle body to ensure that the central hole 411 at the bottom of the rubber stack core shaft 41 can be separated from the sleeve 5 under the unloaded condition of the conical rubber stack 4.

[0064] As shown in the appendix Figure 1 As shown, when the air spring is in the inflated state, the central hole 411 is in contact connection with the sleeve 5, and the compressed gas inside the airbag 2 bears the load and deformation; as shown in the appendix Figure 3 As shown, when the air spring is in the non-air state, the conical rubber stack 4 bears the pressure to make the rubber stack core shaft 41 and the sleeve 5 move relative to each other, and the central hole 411 is separated from the sleeve 5, forming a predetermined gap both horizontally and vertically, and the conical rubber stack 4 bears the load and deformation.

[0065] In some embodiments of the present invention, as shown in the appendix Figure 2 As shown, the inner surface of the central hole 411 is set as a conical surface, and the sleeve is provided with a conical section with an outer wall matching the conical surface. When the air spring is in the inflated state, after the upper cover 1 is separated from the top of the rubber stack core shaft 41, the conical rubber stack 4 makes the central hole 411 and the sleeve 5 come into contact again under the action of the restoring force. During this process, with the cooperation of the conical surface and the conical section, the rubber stack core shaft 41 can be aligned to the central position to achieve automatic centering.

[0066] In some embodiments of the present invention, the fastener 6 is specifically a bolt, which penetrates the sleeve 5 from top to bottom and is inserted into the bottom of the cylinder barrel 3 and fixedly connected to the cylinder barrel 3. A washer is arranged between the bolt and the top of the sleeve 5 to prevent mutual wear.

[0067] In some embodiments of the present invention, as shown in the attached Figure 1 figure, to avoid the sleeve 5 damaging the body of the cylinder barrel 3, a flat support 9 is further arranged in the cylinder barrel 3. The support 9 is located below the conical rubber stack 4 and is fixedly connected to the cylinder barrel 3; the end of the sleeve 5 extending out of the rubber stack core shaft 41 is connected to the support 9. The material of the support 9 is hard metal to improve wear resistance, reduce costs and facilitate replacement.

[0068] In some embodiments of the present invention, as shown in the attached Figure 2 figure, in order to prevent the stiffness of the conical rubber stack 4 from rising steeply and improve comfort, a rubber protrusion 43 is arranged at the bottom of the conical rubber stack 4; when the air spring is airless and in a heavy load state, the rubber protrusion 43 is squeezed and deformed and is in direct or indirect contact connection with the bottom wall of the cylinder barrel 3. Specifically, the rubber protrusion 43 is in contact connection with the upper surface of the flat support 9 at the bottom of the cylinder barrel 3.

[0069] Specifically, as shown in the attached Figure 6 figure, when the vertical force is large, that is, in the case of heavy load, the conical rubber stack 4 is squeezed, and the rubber protrusion 43 at the bottom contacts the upper surface of the support 9, which is equivalent to connecting a rubber spring in series, and can further reduce the stiffness of the conical rubber stack 4, avoid the steep increase in the stiffness of the conical rubber stack 4 in the airless heavy load situation, and improve the riding comfort. At this time, the combined stiffness of the conical rubber stack 4 is K:

[0070] K = K 1 *K 2 / (K 1 +K 2 ).

[0071] Wherein, K 1 is the corresponding stiffness of the conical rubber stack 4 itself, and K 2 is the corresponding stiffness of the rubber protrusion 43.

[0072] In some embodiments of the present invention, as shown in the attached Figure 1 figure, a gasket 7 is arranged between the rubber stack outer sleeve 42 and the cylinder barrel 3. The gasket 7 is used to adjust the compression amount of the conical rubber stack 4, and the number of gaskets 7 is positively correlated with the magnitude of the pre-pressure of the conical rubber stack 4.

[0073] In some embodiments of the present invention, the conical rubber stack 4 needs to be tested before assembling the conical rubber stack 4 to determine its compression amount - vertical force relationship curve, and then determine the number of gaskets 7 to be added.

[0074] In some embodiments of the present invention, as shown in the attached Figure 1As shown, a friction block 8 is fixed to the top of the rubber core shaft 41. In the airless state of the air spring, the upper cover 1 is in contact connection with the friction block 8.

[0075] In some embodiments of the present invention, as shown in the appendix Figure 3 After the central hole 411 is separated from the casing 5, the lateral predetermined gap is Dx0.

[0076] As shown in the appendix Figure 4 As shown, in the airless state of the air spring, due to the relatively large lateral stiffness of the conical rubber stack 4 and the relatively small friction coefficient between the friction block 8 and the upper cover 1, usually less than 0.1, when a lateral force acts on the upper cover 1, relative sliding occurs between the upper cover 1 and the friction block 8 after a predetermined lateral movement distance, and the predetermined distance is Dx1, and Dx1 is less than Dx0, so as to prevent the rubber core shaft 41 from colliding with the casing 5 and causing damage.

[0077] In some embodiments of the present invention, as shown in the appendix Figure 5 As shown, the torsional angle range of the upper cover 1 relative to the horizontal plane is -α to α. When the upper cover 1 twists within the range of -α to α, the central hole 411 and the casing 5 remain separated, that is, the upper cover 1 can freely rotate within the range of ±α without the core shaft contacting the casing 5.

[0078] The working principle of the pre-compressed air spring provided by the embodiments of the present invention is as follows:

[0079] When the air spring is inflated and working normally, the airbag 2 and the internal compressed gas between it and the upper cover 1 and the cylinder barrel 3 bear the load and deformation, playing a buffering and vibration damping role, and the internal conical rubber stack 4 does not work.

[0080] In the case of the air spring being airless, the airbag 2 no longer functions. The upper cover 1 contacts the friction block 8 at the top of the rubber core shaft 41 under the weight of the vehicle body. The conical rubber stack 4 bears the pressure, and the rubber core shaft 41 moves downward and separates from the sleeve. At this time, there are certain vertical and lateral gaps between the central hole 411 of the rubber core shaft 41 and the casing 5, and the conical rubber stack 4 is relatively free, and it bears vertical, lateral, torsional and other loads and deformations.

[0081] Among them, for the lateral load, due to the relatively large lateral stiffness of the internal conical rubber stack 4 and the relatively small friction coefficient between the friction block 8 and the upper cover 1, under the action of the lateral force, relative sliding will occur between the upper cover 1 and the friction block 8 before the central hole 411 of the rubber core shaft 41 laterally contacts the casing 5, so as to prevent the rubber core shaft 41 from colliding with the casing 5 and causing damage. As shown in the appendix Figure 4 As shown, the maximum lateral movement distance Dx1 of the rubber core shaft 41 before the relative sliding between the upper cover 1 and the friction block 8 is less than the predetermined gap Dx0. As shown in the appendix Figure 5 As shown, the maximum torsional angle of the upper cover 1 relative to the horizontal plane is α, that is, the upper cover 1 can freely rotate within the range of ±α without the core shaft contacting the casing 5.

[0082] Some embodiments of the present invention further provide a method for assembling a pre-compressed air spring for assembling the above-mentioned pre-compressed air spring, as shown in the attached Figure 7 - attached Figure 8 figure, including the following steps.

[0083] Place a predetermined number of gaskets 7 inside the cylinder barrel 3.

[0084] Place the support 9 and the conical rubber stack 4 inside the cylinder barrel 3 in sequence.

[0085] Insert the sleeve 5 into the central hole 411 at the bottom of the rubber stack core shaft 41. The outer wall of the conical section of the sleeve 5 fits with the tapered surface of the central hole 411 of the rubber stack core shaft 41 and self-aligns.

[0086] Insert the fastener 6 bolt into the sleeve 5.

[0087] Apply a downward pressure Fz1 to the conical rubber stack 4 using the preloading tooling 11, so that the central hole 411 at the bottom of the rubber stack core shaft 41 is separated from the sleeve 5, and the bottom of the sleeve 5 contacts the upper surface of the support 9.

[0088] Insert the adjustment tooling into the preloading tooling 11, tighten the fasteners 6 such as bolts to a predetermined torque, and adjust the sleeve 5 to a predetermined height. Among them, the adjustment tooling is an Allen wrench and an extension rod 11.

[0089] Slowly release the pressure of the preloading tooling 11 on the conical rubber stack 4, so that the upper surface of the central hole 411 at the bottom of the rubber stack core shaft 41 contacts and is pressed by the sleeve 5, and the installation of the components inside the cylinder barrel 3 is completed.

[0090] After the installation of the components inside the cylinder barrel 3 is completed, place the friction block 8 at the top of the rubber stack core shaft 41 and align it in the center, and install and fix it with screws.

[0091] Place the airbag 2 in the center on the support seat of the cylinder barrel 3, and use a nylon rod and a rubber hammer to tap the lower collar of the airbag 2 in place, so that the lower collar of the airbag 2 fits tightly with the support seat of the cylinder barrel 3 and is hermetically connected.

[0092] Place the upper cover 1 in the center on the airbag 2, move the combination of the upper cover 1, the airbag 2 and the cylinder barrel 3 to the inflation equipment, and use pressure to press the upper collar of the airbag 2 in place, so that the upper collar of the airbag 2 fits tightly with the upper cover 1 and is hermetically connected, and the assembly is completed.

[0093] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same and similar parts among the various embodiments can be referred to each other.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A pre-compressed air spring, characterized in that: include: Upper cover, cylinder, air bag and conical rubber pile; The upper and lower sub-ports of the airbag are respectively sealed and connected to the upper cover and the cylinder; A conical rubber pile and a sleeve are arranged in the cylinder; The conical rubber pile includes a rubber pile core shaft and a rubber pile outer sleeve; the rubber pile outer sleeve is sleeved on the outside of the rubber pile core shaft; the bottom wall of the rubber pile core shaft is provided with a central hole; The sleeve passes through the central hole and is fixedly connected to the cylinder; When the air spring is inflated, the center hole is in contact with the sleeve, and the compressed gas inside the airbag bears the load and deformation; when the air spring is deflated, the conical rubber pile is under pressure so that the core axis of the rubber pile and the sleeve move relative to each other, the center hole is separated from the sleeve, and a predetermined gap is formed in the horizontal and vertical directions, and the conical rubber pile bears the load and deformation.

2. The pre-compressed air spring according to claim 1, characterized in that: A rubber protrusion is arranged at the bottom of the conical rubber pile; when the air spring is deflated and in a heavy-loaded state, the rubber protrusion contacts the upper surface of the base.

3. The pre-compressed air spring according to claim 2, characterized in that: The corresponding stiffness of the conical rubber pile body is K1, and the corresponding stiffness of the rubber protrusion is K2; the combined stiffness of the conical rubber pile body and the rubber protrusion is K: K = K1*K2 / (K1+K2).

4. The pre-compressed air spring according to claim 1, characterized in that: The center hole is provided with a conical surface, and the sleeve is provided with a conical section matching the conical surface. In the process of contact between the center hole and the sleeve, automatic centering is achieved with the cooperation of the conical surface and the conical section.

5. The pre-compressed air spring according to claim 1, characterized in that: A gasket is arranged between the rubber pile outer shell and the cylinder barrel, and the gasket is used to adjust the compression amount of the conical rubber pile. The number of the gaskets is positively correlated with the size of the pre-pressure of the conical rubber pile.

6. The pre-compressed air spring according to claim 1, characterized in that: A friction block is fixed on the top of the rubber pile core shaft, and when the air spring is deflated, the upper cover is in contact with and connected to the friction block.

7. The pre-compressed air spring according to claim 5, characterized in that: After the central hole is separated from the sleeve, the predetermined lateral gap is Dx0; When the air spring is deflated, when the upper cover is subjected to a lateral force, the upper cover and the friction block slide relative to each other after lateral displacement by a predetermined distance, wherein the predetermined distance is Dx1, and Dx1 is smaller than Dx0.

8. The pre-compressed air spring according to claim 1 or 5, characterized in that: The torsion angle range of the upper cover relative to the horizontal plane is -α to α. When the upper cover is twisted within the range of -α to α, the central hole and the sleeve remain separated.

9. The pre-compressed air spring according to claim 1, characterized in that: A flat support is further arranged in the cylinder, the support is located below the conical rubber pile and is fixedly connected to the cylinder; the end of the sleeve extending out of the core shaft of the rubber pile is connected to the support.

10. A method for assembling a pre-compressed air spring, used for assembling the pre-compressed air spring according to any one of claims 1 to 9, characterized in that: The following steps are involved: Place the base and the conical rubber pile in the cylinder in sequence; Insert the sleeve into the center hole at the bottom of the rubber pile mandrel; Use a pre-pressing tool to apply pressure to the conical rubber pile so that the center hole at the bottom of the rubber pile core shaft is separated from the sleeve; Use the adjusting tool to adjust the sleeve to a predetermined height and then fix it to the cylinder; Releasing the pressure of the pre-pressing tool on the conical rubber pile, so that the upper surface of the central hole at the bottom of the core shaft of the rubber pile is in contact with the sleeve and under pressure; Place the airbag centrally on the cylinder barrel so that the lower opening of the airbag is sealed and connected to the cylinder barrel; Place the upper cover on the airbag in the center so that the upper opening of the airbag is sealed and connected with the upper cover.

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