Design method of composite material upper cover plate of air spring for railway vehicle

Abstract

The invention relates to the technical field of air springs for railway vehicles, in particular to a design method of a composite upper cover plate of an air spring for railway vehicles, the air spring comprises a conical spring, a wearing plate, an air bag and the upper cover plate made of composite materials, bolt holes are formed in the upper cover plate in the circumferential direction, and metal steel sleeves are glued in the bolt holes. A middle hole located on the inner side of the bolt hole is formed in the middle of the upper cover plate, an air guide pipe is installed in the middle hole in a gluing mode, or the air guide pipe is installed in the middle hole in an interference press-fitting and gluing combined mode, or the air guide pipe is installed in the middle hole in an gluing and bolt connection combined mode, and a containing groove is formed in the lower end of the upper cover plate. The containing groove is located in the inner side of the bolt hole, and a metal friction plate is arranged in the containing groove. According to the scheme, the air spring is good in strength performance, the upper cover plate has the advantages of being light in weight, high in fatigue performance and high in environmental adaptability, and the technical effects of weight reduction and carbon reduction can be achieved.

Description

Technical Field

[0001] This invention relates to the field of air spring technology for rail vehicles, and specifically provides a design method for a composite material top cover plate for an air spring for rail vehicles. Background Technology

[0002] The air spring is an important elastic damping component in the secondary suspension of the bogie elastic suspension system of a railcar. It is installed between the train car body and the bogie and bears the vertical and horizontal loads between the car body and the bogie. The main functions of the air spring are to provide a comfortable ride, improve driving safety, and reduce the impact on the track and vehicle structure.

[0003] The air springs used in rails have a complex structure, usually assembled from multiple components such as an upper cover plate, air bladder, upper buckle, wear-resistant plate, support plate, and auxiliary spring. Currently, most components are made of metal materials, which results in a high carbon emission factor for the system, as well as a heavy weight and high raw material costs. Therefore, it is necessary to make the air springs lighter.

[0004] The top cover plate is a crucial component of the air spring. Existing top covers primarily use either aluminum or painted aluminum plates, which presents the following problems: 1) The wear-resistant plate below can only meet the requirement of a friction coefficient ≤0.1 when used in combination with the aluminum cover plate while greased. However, greasing is cumbersome to operate and maintain, and can easily lead to instability, affecting safety and reliability. Painting the aluminum cover plate involves a complex process, including multiple steps such as primer spraying, topcoat spraying, and baking / curing, resulting in high processing costs. Furthermore, the paint is flammable and has poor wear resistance. 2) Metal top covers are heavy and have high raw material costs, making lightweighting the air spring essential. 3) Metal top covers have high carbon emissions, failing to meet low-carbon and environmental protection requirements.

[0005] Therefore, it is necessary to design the top cover plate of the air spring, and replace the existing aluminum alloy top cover plate with a composite material top cover plate. This paper provides a design method for a composite material top cover plate for air springs used in rail vehicles, which can reduce weight and carbon emissions while ensuring strength performance and increasing the fatigue performance of the air spring. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a design method for a composite material top cover plate for air springs used in rail vehicles, which can improve the product's fatigue performance, increase strength, reduce stress concentration in bolts, and achieve weight reduction and carbon reduction.

[0007] This invention provides a design method for a composite material top cover plate of an air spring for rail vehicles. The air spring includes a conical spring, a wear plate located at the upper end of the conical spring, and an air bladder. The upper end of the air bladder is provided with a top cover plate located above the wear plate. The top cover plate is made of composite material. Bolt holes are opened circumferentially on the top cover plate, and metal steel sleeves are glued into the bolt holes. A central hole is opened in the middle of the top cover plate, located inside the bolt holes. An air guide pipe is installed in the central hole by adhesive bonding, or by interference fit combined with adhesive bonding, or by adhesive bonding combined with bolt connection, or by integral molding. The air guide pipe and the upper end face of the top cover plate are all sealed by adhesive bonding.

[0008] Furthermore, a column-shaped central hole is opened in the middle of the upper cover plate, and an air guide tube is installed in the central hole by adhesive. The air guide tube includes a lower end connecting platform that is adhesively connected or press-fitted to the inner wall of the column of the central hole. The lower end connecting platform forms a lateral stop during operation. An upper retaining platform is provided above the lower end connecting platform and extends outward. The upper retaining platform is adhesively bonded to the upper end surface of the upper cover plate.

[0009] Furthermore, a stepped central hole is opened in the middle of the upper cover plate. The central hole includes an upper cylindrical platform and a lower cylindrical hole. The inner diameter of the upper cylindrical platform is larger than the inner diameter of the lower cylindrical hole. The upper cylindrical platform is formed by opening the upper end face of the upper cover plate downwards. The air guide pipe includes an upper retaining platform placed on the upper cylindrical platform and a lower connecting platform connected to the lower cylindrical hole. The lower connecting platform forms a lateral stop during operation. The bottom end face of the upper retaining platform is glued to the upper end face of the upper cylindrical platform. The outer end face of the upper retaining platform is glued to the outer wall of the upper cylindrical platform. The lower connecting platform is connected to the cylindrical inner wall of the lower cylindrical hole by adhesive bonding or by interference fit.

[0010] Furthermore, a stepped central hole is opened in the middle of the upper cover plate. The central hole includes an upper cylindrical platform and a lower cylindrical hole. The inner diameter of the upper cylindrical platform is larger than the inner diameter of the lower cylindrical hole. The upper cylindrical platform is formed by opening the upper end face of the upper cover plate downwards. The air guide tube includes an upper retaining platform placed on the upper cylindrical platform. The bottom end face of the upper retaining platform is glued to the upper end face of the upper cylindrical platform, and the outer end face of the upper retaining platform is glued to the outer wall of the upper cylindrical platform.

[0011] Furthermore, a stepped central hole is formed in the middle of the upper cover plate. The central hole includes an upper cylindrical platform and a lower cylindrical hole. The upper cylindrical platform is formed by the upper end face of the upper cover plate facing downwards. The lower end face of the upper cover plate is formed by the portion of the lower cylindrical hole facing upwards, forming a lower cylindrical platform. The inner diameter of the upper cylindrical platform is larger than the inner diameter of the lower cylindrical platform, and the inner diameter of the lower cylindrical platform is larger than the inner diameter of the lower cylindrical hole. The air guide tube includes an upper retaining platform placed on the upper cylindrical platform. The bottom end face of the upper retaining platform is glued to the upper end face of the upper cylindrical platform, and the outer end face of the upper retaining platform is glued to the outer wall of the upper cylindrical platform. The upper cover plate has an installation hole that matches the fastening hole in the air guide tube, which is formed from the bottom end face of the lower cylindrical platform facing upwards. Fastening bolts are installed in the installation hole and the fastening hole. After the fastening bolts are installed, the fastening bolts are completely accommodated in the lower cylindrical platform or the bottom end face of the fastening bolts is flush with the lower end face of the upper cover plate.

[0012] Furthermore, a stepped central hole is opened in the middle of the upper cover plate. The central hole includes an upper cylindrical hole and a lower cylindrical platform. The lower cylindrical platform is formed by opening the lower end face of the upper cover plate facing upward. The inner diameter of the upper cylindrical hole is smaller than the inner diameter of the lower cylindrical platform. The air guide tube includes a lower end connecting platform placed in the lower cylindrical platform and an upper locking platform connected in the upper cylindrical hole. The side end face of the upper locking platform is glued or press-fitted to the hole wall of the upper cylindrical hole, and the lower end connecting platform is glued to the lower cylindrical platform.

[0013] Furthermore, a receiving groove is opened at the lower end of the upper cover plate. The receiving groove is located inside the bolt hole. A metal friction plate is installed in the receiving groove. A central through hole is opened in the middle of the metal friction plate to match the central hole.

[0014] Furthermore, the bottom end face of the lower end connecting platform of the air duct is located above the bottom end face of the metal friction plate.

[0015] Furthermore, stepped bolt holes are made on the upper cover plate, specifically including a column-shaped upper adhesive platform and a column-shaped lower adhesive hole. The inner diameter of the upper adhesive platform is larger than the inner diameter of the lower adhesive hole. The metal sleeve includes an upper steel sleeve glued to the upper adhesive platform and a lower steel sleeve glued to the lower adhesive hole. The upper end face of the upper steel sleeve faces downward and the inner end face of the lower steel sleeve has a tapered inner wall with a gradually decreasing inner diameter. The lower end of the tapered inner wall is the columnar inner wall of the lower steel sleeve, so that an upper tapered connecting hole and a lower columnar connecting hole are formed inside the metal sleeve. Connecting bolts are provided in the bolt holes, and a retaining ring is provided between the upper cover plate and the airbag. The connecting bolts lock the upper cover plate and the retaining ring in the upper tapered connecting hole and the lower columnar connecting hole.

[0016] Furthermore, a two-section bolt hole structure is provided in the upper cover plate, specifically including a column-shaped lower adhesive hole and a cone-shaped upper adhesive platform with an inner diameter that gradually decreases from top to bottom; the metal sleeve includes an upper steel sleeve glued to the upper adhesive platform and a lower steel sleeve glued to the lower adhesive hole, with an upper cone-shaped connecting hole formed in the upper steel sleeve and a lower column-shaped connecting hole formed in the lower steel sleeve; connecting bolts are provided in the bolt holes, and a retaining ring is provided between the upper cover plate and the airbag, with the connecting bolts locking the upper cover plate and the retaining ring in the upper cone-shaped connecting hole and the lower column-shaped connecting hole.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: The air spring in this invention uses a composite material top cover plate instead of the existing aluminum alloy top cover plate, which can achieve the effect of weight reduction and carbon reduction, with a weight reduction of >25% and a carbon reduction of >70%, and the strength performance reaches 400MPa.

[0018] The composite material top cover of the present invention has the following advantages over traditional metal top covers: 1) Lightweight: The composite material cover plate in this invention has a higher specific strength, and has higher strength and stiffness for the same weight of material; 2) High strength and fatigue resistance: The composite material cover plate in this invention can achieve better strength performance through topology optimization process, and at the same time has better fatigue performance; 3) Environmental adaptability: The composite material cover plate in this invention has a low coefficient of thermal expansion, maintains small structural deformation at high and low temperatures, and has good corrosion resistance; 4) Environmental friendliness: The composite material cover plate in this invention has a lower carbon emission factor compared to metal materials such as aluminum alloy; 5) The bolt hole positions on the upper cover plate of this invention are designed with metal inserts, which can greatly reduce stress concentration at the bolt hole positions; 6) The sealing ring has been eliminated. The air guide tube and the intermediate hole are connected by adhesive and bolts through gap assembly, or by pure adhesive, or by adhesive and interference fit. This ensures reliable sealing and connection, reduces the processing difficulty of the intermediate hole, and saves materials. At the same time, when the lower part of the air guide tube is pressed or glued into the intermediate hole, the lower end of the air guide tube is flush with the lower end of the air guide tube, and the lower end of the air guide tube can achieve a lateral stop function. 7) A metal friction plate is embedded on the lower surface of the lower cover plate. When the air spring fails, the metal friction plate rubs against the composite wear plate (low coefficient of friction), avoiding dry friction between the composite upper cover plate and the composite wear plate (high coefficient of friction), and also avoiding the need to apply grease to the original plate. This saves on the process while ensuring low friction effect. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the structure of the composite material top cover plate provided in Embodiment 1 of the present invention; Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of the structure of the composite material top cover plate provided in Embodiment 2 of the present invention; Figure 4 yes Figure 3 A magnified view of a section at point B in the middle; Figure 5 yes Figure 3 A magnified view of a section at point C; Figure 6 This is a schematic diagram of the structure of the composite material top cover plate provided in Embodiment 3 of the present invention; Figure 7 This is a schematic diagram of the structure of the composite material top cover plate provided in Embodiment 4 of the present invention; Figure 8 yes Figure 7 A partial schematic diagram; Figure 9 This is a schematic diagram of the structure of an air spring provided according to Embodiment 5 of the present invention; Figure 10 This is a schematic diagram of the structure of the composite material cover plate provided in Embodiment Six of the present invention.

[0020] The reference numerals in the attached drawings include: 1. Conical spring; 2. Wear plate; 3. Airbag; 4. Upper cover plate; 5. Buckle; 6. Metal steel sleeve; 7. Middle hole; 8. Air duct; 9. Lower connecting platform; 10. Upper locking platform; 11. Upper cylindrical platform; 12. Lower cylindrical hole; 13. Fastening hole; 14. Mounting hole; 15. Fastening bolt; 16. Lower cylindrical platform; 17. Metal friction plate; 18. Upper adhesive platform; 19. Lower adhesive hole; 20. Upper steel sleeve; 21. Lower steel sleeve; 22. Conical inner wall; 23. Cylindrical inner wall; 24. Upper conical connecting hole; 25. Lower cylindrical connecting hole; 26. Upper cylindrical hole. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with the appendix. Figure 1-10 The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and do not constitute a limitation thereof.

[0022] A design method for a composite material top cover plate for an air spring used in rail vehicles, such as... Figure 9As shown, the air spring includes a conical spring 1, a wear plate 2 located at the upper end of the conical spring 1, and an airbag 3. The upper end of the airbag 3 is provided with an upper cover plate 4 located above the wear plate 2. The upper cover plate 4 is made of composite material. In this embodiment, the upper cover plate 4 is made of continuous fiber reinforced epoxy resin or continuous fiber reinforced nylon material. It is made by molding or vacuum injection molding. Those skilled in the art can also use other composite materials to make the upper cover plate 4 according to the actual situation. A buckle 5 is provided between the upper cover plate 4 and the airbag 3. The upper cover plate 4 is connected to the buckle 5, and the airbag 3 is fastened to the buckle 5. An air guide tube 8 is connected to the upper cover plate 4 and communicates with the airbag 3. Example 1

[0023] This implementation example Figure 1 , Figure 2 As shown, bolt holes are made circumferentially on the upper cover plate 4, and metal sleeves 6 are glued into the bolt holes. A central hole 7 is made in the middle of the upper cover plate 4, located inside the bolt holes. An air guide pipe 8 is installed in the central hole 7 by adhesive bonding. The air guide pipe 8 and the upper end face of the upper cover plate 4 are both glued together to achieve a seal. Therefore, the use of a sealing ring can be eliminated, which can save materials and process flow. The metal sleeve 6 can reduce stress concentration at the bolt holes and improve connection strength.

[0024] Specifically, a column-shaped central hole 7 is opened in the middle of the upper cover plate 4. An air guide pipe 8 is installed in the central hole 7 by adhesive. The air guide pipe 8 includes a lower end connecting platform 9 that connects to the inner wall of the column of the central hole 7. The lower end connecting platform 9 forms a lateral stop during operation. An upper locking platform 10 extends outward above the lower end connecting platform 9. The upper locking platform 10 is glued to the upper end face of the upper cover plate 4, which can achieve self-sealing at the connection between the upper locking platform 10 and the upper cover plate 4, thereby improving the service life of the product.

[0025] A stepped bolt hole is made on the upper cover plate 4, specifically including a column-shaped upper adhesive platform 18 and a column-shaped lower adhesive hole 19. The inner diameter of the upper adhesive platform 18 is larger than the inner diameter of the lower adhesive hole 19. The metal sleeve 6 includes an upper steel sleeve 20 glued to the upper adhesive platform 18 and a lower steel sleeve 21 glued to the lower adhesive hole 19. In this embodiment, the metal sleeve 6 is thicker, which can better improve the strength and reduce stress concentration. The column-shaped upper adhesive platform 18 and the column-shaped lower adhesive hole 19 are easy to process. During installation, the metal sleeve 6 can be pre-embedded and installed by mold opening, or it can be assembled manually without mold opening.

[0026] The upper end face of the upper steel sleeve 20 faces downward and the inner end face of the lower steel sleeve 21 is opened into a tapered inner wall 22 with a gradually decreasing inner diameter. The lower end of the tapered inner wall 22 is the cylindrical inner wall 23 of the lower steel sleeve 21, so that an upper tapered connecting hole 24 and a lower cylindrical connecting hole 25 are formed in the metal steel sleeve 6. A connecting bolt is provided in the bolt hole. The connecting bolt locks the upper cover plate 4 and the buckle ring 5 in the upper tapered connecting hole 24 and the lower cylindrical connecting hole 25.

[0027] In this embodiment, the top cover plate 4 is lightweight and easy to process, and is suitable for wet friction with the wear-resistant plate 2 (PTFE, ultra-high molecular weight polyethylene, nylon, etc.) when coated with grease, resulting in a low coefficient of friction. Example 2

[0028] The difference between this embodiment and Embodiment 1 is that, for example, this embodiment... Figure 3 , Figure 4 , Figure 5 As shown, a stepped intermediate hole 7 is opened in the middle of the upper cover plate 4. The intermediate hole 7 includes an upper cylindrical platform 11 and a lower cylindrical hole 12. The inner diameter of the upper cylindrical platform 11 is larger than the inner diameter of the lower cylindrical hole 12. The upper cylindrical platform 11 is formed by opening the upper end face of the upper cover plate 4 downwards. The air guide pipe 8 includes an upper retaining platform 10 placed on the upper cylindrical platform 11 and a lower end connecting platform 9 connected to the lower cylindrical hole 12. The lower end connecting platform 9 forms a lateral stop during operation. The bottom end face of the upper retaining platform 10 is glued to the upper end face of the upper cylindrical platform 11, and the outer end face of the upper retaining platform 10 is glued to the outer wall of the upper cylindrical platform 11, which can achieve a seal without the need for a separate sealing ring. The lower end connecting platform 9 is connected to the cylindrical inner wall of the lower cylindrical hole 12 by interference fit. In this embodiment, the air guide pipe 8 is installed by a combination of interference fit and adhesive.

[0029] The upper cover plate 4 has a two-section bolt hole structure, specifically including a column-shaped lower adhesive hole 19 and a cone-shaped upper adhesive platform 18 with an inner diameter that gradually decreases from top to bottom. The metal sleeve 6 includes an upper steel sleeve 20 glued to the upper adhesive platform 18 and a lower steel sleeve 21 glued to the lower adhesive hole 19. An upper cone-shaped connecting hole 24 is formed in the upper steel sleeve 20, and a lower column-shaped connecting hole 25 is formed in the lower steel sleeve 21. A connecting bolt is provided in the bolt hole. A retaining ring 5 is provided between the upper cover plate 4 and the airbag 3. The connecting bolt locks the upper cover plate 4 and the retaining ring 5 in the upper cone-shaped connecting hole 24 and the lower column-shaped connecting hole 25.

[0030] A receiving groove is formed at the lower end of the upper cover plate 4, located inside the bolt hole. A metal friction plate 17 is installed inside the receiving groove, and a central through hole is formed in the middle of the metal friction plate 17 to match the central hole 7. Figure 5As shown, the bottom end face of the lower end connecting platform 9 of the air guide pipe 8 is located above the bottom end face of the metal friction plate 17. When the product malfunctions and the airbag 3 deflates, the upper cover plate 4 will rub against the wear-resistant plate 2. If both the upper cover plate 4 and the wear-resistant plate 2 are composite materials, the composite materials will directly rub against each other, resulting in a high coefficient of friction, which can reach 0.15-0.18. However, the product requires a coefficient of friction of less than 0.1. To meet this requirement, it can only be achieved by spraying grease onto the original plate. However, applying grease will increase costs, increase the process flow, and reduce work efficiency. In this solution, the upper cover plate 4 can rub against the wear-resistant plate 2, which can meet the requirement of a coefficient of friction of less than 0.1.

[0031] In this embodiment, by adding a metal friction plate 17 at the lower end of the upper cover plate 4, when the product malfunctions, the metal friction plate 17 rubs against the wear-resistant plate 2 of the composite material, that is, the friction between the metal and the composite material, which greatly reduces the coefficient of friction, meeting the requirement of a coefficient of friction of less than 0.1, and there is no need to apply grease. At the same time, the bottom end of the lower end connecting platform 9 of the air duct 8 is located above the bottom end of the metal friction plate 17, which may ensure that the wear-resistant plate 2 only rubs against the metal friction plate 17, avoiding friction between the wear-resistant plate 2 of the composite material and the lower end connecting platform 9 of the composite material. Example 3

[0032] The difference between this embodiment and Embodiment 2 is that, for example, this embodiment... Figure 6 As shown, a stepped intermediate hole 7 is opened in the middle of the upper cover plate 4. The intermediate hole 7 includes an upper cylindrical platform 11 and a lower cylindrical hole 12. The inner diameter of the upper cylindrical platform 11 is larger than the inner diameter of the lower cylindrical hole 12. The upper cylindrical platform 11 is formed by opening the upper end face of the upper cover plate 4 downward. The air guide tube 8 includes an upper retaining platform 10 placed on the upper cylindrical platform 11. The bottom end face of the upper retaining platform 10 is glued to the upper end face of the upper cylindrical platform 11, and the outer end face of the upper retaining platform 10 is glued to the outer side wall of the upper cylindrical platform 11. In this embodiment, the air guide tube 8 is connected by adhesive bonding. Example 4

[0033] The difference between this embodiment and Embodiment 1 is that, for example, this embodiment... Figure 7 , Figure 8As shown, a stepped central hole 7 is formed in the middle of the upper cover plate 4. The central hole 7 includes an upper cylindrical platform 11 and a lower cylindrical hole 12. The upper cylindrical platform 11 is formed by opening the upper end face of the upper cover plate 4 downwards. The lower end face of the upper cover plate 4 is formed by opening the portion outside the lower cylindrical hole 12 upwards to form a lower cylindrical platform 16. The inner diameter of the upper cylindrical platform 11 is larger than the inner diameter of the lower cylindrical platform 16, and the inner diameter of the lower cylindrical platform 16 is larger than the inner diameter of the lower cylindrical hole 12. An installation hole 13 matching the fastening hole 13 in the air guide pipe 8 is formed on the upper cover plate 4 from the bottom end face of the lower cylindrical platform 16 upwards. Hole 14, mounting hole 14 and fastening hole 13 are provided with fastening bolts 15. After the fastening bolts 15 are installed, the fastening bolts 15 are completely contained in the lower columnar platform 16 or the bottom end face of the fastening bolts 15 is flush with the lower end face of the upper cover plate 4 to prevent interference. The air guide tube 8 includes an upper retaining platform 10 placed on the upper columnar platform 11. The bottom end face of the upper retaining platform 10 is glued to the upper end face of the upper columnar platform 11, and the outer end face of the upper retaining platform 10 is glued to the outer side wall of the upper columnar platform 11. In this embodiment, the air guide tube 8 is installed by means of glued connection and bolt connection. Example 5

[0034] The difference between this embodiment and Embodiment 4 is that, for example, this embodiment... Figure 9 As shown, the upper cover plate 4 has a two-section bolt hole structure, specifically including a column-shaped lower adhesive hole 19 and a cone-shaped upper adhesive platform 18 with an inner diameter that gradually decreases from top to bottom. The metal sleeve 6 includes an upper steel sleeve 20 glued to the upper adhesive platform 18 and a lower steel sleeve 21 glued to the lower adhesive hole 19. An upper cone-shaped connecting hole 24 is formed in the upper steel sleeve 20, and a lower column-shaped connecting hole 25 is formed in the lower steel sleeve 21. A connecting bolt is provided in the bolt hole. A retaining ring 5 is provided between the upper cover plate 4 and the airbag 3. The connecting bolt locks the upper cover plate 4 and the retaining ring 5 in the upper cone-shaped connecting hole 24 and the lower column-shaped connecting hole 25. Example 6

[0035] The difference between this embodiment and Embodiment 3 is that, for example, this embodiment... Figure 10 As shown, a stepped central hole 7 is opened in the middle of the upper cover plate 4. The central hole 7 includes an upper cylindrical hole 26 and a lower cylindrical platform 16. The lower cylindrical platform 16 is formed by opening the lower end face of the upper cover plate 4 upward. The inner diameter of the upper cylindrical hole 26 is smaller than the inner diameter of the lower cylindrical platform 16. The air guide tube 8 includes a lower end connecting platform 9 placed in the lower cylindrical platform 16 and an upper locking platform 10 connected in the upper cylindrical hole 26. The side end face of the upper locking platform 10 is glued or press-fitted to the hole wall of the upper cylindrical hole 26. The lower end connecting platform 9 is glued to the lower cylindrical platform 16. The structure in this embodiment is easy to install. When the load causes the air pressure in the airbag 3 to push upward, and the air pressure is very high, the lower end connecting platform 9 will form a limit in the lower cylindrical platform 16 to prevent the air guide tube 8 from being pushed out, thereby improving the connection strength of the air guide tube 8 and the service life of the product. Example 7

[0036] The difference between this embodiment and embodiment one is that the air guide pipe 8 is installed in the middle hole 7 by integral molding, that is, the air guide pipe 8 is located in the middle hole 7, and the air guide pipe 8 and the upper cover plate 4 are integrally molded. In this embodiment, the air guide pipe 8 is also made of composite material, and the air guide pipe 8 and the upper cover plate 4 are molded as a whole.

[0037] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0038] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A design method for a composite material top cover plate of an air spring for rail vehicles, the air spring comprising a conical spring (1), a wear plate (2) located at the upper end of the conical spring (1), and an air bladder (3), wherein the upper end of the air bladder (3) is provided with a top cover plate (4) located above the wear plate (2), characterized in that, The top cover plate (4) is made of composite material. Bolt holes are opened along the circumference of the top cover plate (4), and metal steel sleeves (6) are glued into the bolt holes. A middle hole (7) is opened in the middle of the top cover plate (4) and located inside the bolt holes. The air guide pipe (8) is installed in the middle hole (7) by gluing, or by interference fit and gluing, or by gluing and bolt connection, or by integral molding. The air guide pipe (8) and the upper end face of the top cover plate (4) are sealed by gluing.

2. The design method for the composite material top cover plate of the air spring for rail vehicles according to claim 1, characterized in that, A column-shaped central hole (7) is opened in the middle of the upper cover plate (4), and an air guide pipe (8) is installed in the central hole (7) by adhesive bonding. The air guide pipe (8) includes a lower end connecting platform (9) that is adhesively connected or press-fitted to the inner wall of the column of the central hole (7). The lower end connecting platform (9) forms a lateral stop during operation. An upper locking platform (10) is provided above the lower end connecting platform (9) and extends outward. The upper locking platform (10) is adhesively bonded to the upper end surface of the upper cover plate (4).

3. The design method for the composite material top cover plate of the air spring for rail vehicles according to claim 1, characterized in that, A stepped intermediate hole (7) is opened in the middle of the upper cover plate (4). The intermediate hole (7) includes an upper cylindrical platform (11) and a lower cylindrical hole (12). The inner diameter of the upper cylindrical platform (11) is larger than the inner diameter of the lower cylindrical hole (12). The upper cylindrical platform (11) is formed by the upper end face of the upper cover plate (4) facing downward. The air guide pipe (8) includes an upper locking platform (10) placed on the upper cylindrical platform (11) and a lower end connecting platform (9) connected to the lower cylindrical hole (12). The lower end connecting platform (9) forms a transverse stop during operation. The bottom end face of the upper locking platform (10) is glued to the upper end face of the upper cylindrical platform (11). The outer end face of the upper locking platform (10) is glued to the outer wall of the upper cylindrical platform (11). The lower end connecting platform (9) is connected to the cylindrical inner wall of the lower cylindrical hole (12) by glue or by interference fit.

4. The design method for the composite material top cover plate of the air spring for rail vehicles according to claim 1, characterized in that, A stepped intermediate hole (7) is opened in the middle of the upper cover plate (4). The intermediate hole (7) includes an upper cylindrical platform (11) and a lower cylindrical hole (12). The inner diameter of the upper cylindrical platform (11) is larger than the inner diameter of the lower cylindrical hole (12). The upper cylindrical platform (11) is formed by opening the upper end face of the upper cover plate (4) downward. The air guide pipe (8) includes an upper retaining platform (10) placed on the upper cylindrical platform (11). The bottom end face of the upper retaining platform (10) is glued to the upper end face of the upper cylindrical platform (11), and the outer end face of the upper retaining platform (10) is glued to the outer wall of the upper cylindrical platform (11).

5. The design method for the composite material top cover plate of the air spring for rail vehicles according to claim 1, characterized in that, A stepped intermediate hole (7) is opened in the middle of the upper cover plate (4). The intermediate hole (7) includes an upper cylindrical platform (11) and a lower cylindrical hole (12). The upper cylindrical platform (11) is opened with the upper end face of the upper cover plate (4) facing downward. The lower end face of the upper cover plate (4) is opened with the portion outside the lower cylindrical hole (12) facing upward to form a lower cylindrical platform (16). The inner diameter of the upper cylindrical platform (11) is larger than the inner diameter of the lower cylindrical platform (16), and the inner diameter of the lower cylindrical platform (16) is larger than the inner diameter of the lower cylindrical hole (12). The air guide tube (8) includes an upper clamping platform (10) placed on the upper cylindrical platform (11). The bottom end face of the platform (10) is glued to the top end face of the upper columnar platform (11), and the outer end face of the upper platform (10) is glued to the outer wall of the upper columnar platform (11). The upper cover plate (4) has an installation hole (14) that matches the fastening hole (13) in the air guide pipe (8) from the bottom end face of the lower columnar platform (16). Fastening bolts (15) are provided in the installation hole (14) and the fastening hole (13). After the fastening bolts (15) are installed, the fastening bolts (15) are completely contained in the lower columnar platform (16) or the bottom end face of the fastening bolts (15) is flush with the bottom end face of the upper cover plate (4).

6. The design method for the composite material top cover plate of the air spring for rail vehicles according to claim 1, characterized in that, A stepped intermediate hole (7) is opened in the middle of the upper cover plate (4). The intermediate hole (7) includes an upper cylindrical hole (26) and a lower cylindrical platform (16). The lower cylindrical platform (16) is formed by opening the lower end face of the upper cover plate (4) upward. The inner diameter of the upper cylindrical hole (26) is smaller than the inner diameter of the lower cylindrical platform (16). The air guide pipe (8) includes a lower end connecting platform (9) placed in the lower cylindrical platform (16) and an upper locking platform (10) connected in the upper cylindrical hole (26). The side end face of the upper locking platform (10) is glued or press-fitted to the hole wall of the upper cylindrical hole (26). The lower end connecting platform (9) is glued to the lower cylindrical platform (16).

7. The design method of the composite material top cover plate for the air spring of a rail vehicle according to any one of claims 1-6, characterized in that, A receiving groove is opened at the lower end of the upper cover plate (4). The receiving groove is located inside the bolt hole. A metal friction plate (17) is set in the receiving groove. A central through hole is opened in the middle of the metal friction plate (17) to match the central hole (7).

8. The design method for the composite material top cover plate of the air spring for rail vehicles according to claim 7, characterized in that, The bottom end face of the lower end connecting platform (9) of the air duct (8) is located above the bottom end face of the metal friction plate (17).

9. The design method of the composite material top cover plate for the air spring of a rail vehicle according to any one of claims 1-6, characterized in that, A stepped bolt hole is made on the upper cover plate (4), specifically including a column-shaped upper adhesive platform (18) and a column-shaped lower adhesive hole (19). The inner diameter of the upper adhesive platform (18) is larger than the inner diameter of the lower adhesive hole (19). The metal sleeve (6) includes an upper steel sleeve (20) glued to the upper adhesive platform (18) and a lower steel sleeve (21) glued to the lower adhesive hole (19). The upper end face of the upper steel sleeve (20) faces the inner end face of the lower steel sleeve (21) and the inner end face faces downward. The tapered inner wall (22) with a gradually decreasing diameter has a cylindrical inner wall (23) at the lower end of the tapered inner wall (22) that forms an upper tapered connecting hole (24) and a lower cylindrical connecting hole (25) inside the metal steel sleeve (6). A connecting bolt is provided in the bolt hole, and a buckle (5) is provided between the upper cover plate (4) and the airbag (3). The connecting bolt locks the upper cover plate (4) and the buckle (5) in the upper tapered connecting hole (24) and the lower cylindrical connecting hole (25).

10. The design method of the composite material top cover plate for the air spring of a rail vehicle according to any one of claims 1-6, characterized in that, The upper cover plate (4) has a two-section bolt hole structure, specifically including a column-shaped lower adhesive hole (19) and a cone-shaped upper adhesive platform (18) with an inner diameter that gradually decreases from top to bottom; the metal sleeve (6) includes an upper steel sleeve (20) glued to the upper adhesive platform (18) and a lower steel sleeve (21) glued to the lower adhesive hole (19). An upper cone-shaped connecting hole (24) is formed in the upper steel sleeve (20), and a lower column-shaped connecting hole (25) is formed in the lower steel sleeve (21); the bolt hole is provided with a connecting bolt, and a buckle (5) is provided between the upper cover plate (4) and the airbag (3). The connecting bolt locks the upper cover plate (4) and the buckle (5) in the upper cone-shaped connecting hole (24) and the lower column-shaped connecting hole (25).

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