A heave piston for air spring and air spring

Abstract

The present application relates to the field of air spring, and relates to a heave piston for air spring and air spring, wherein the heave piston for air spring comprises a piston body, the piston body is sequentially provided with a lower mounting section, a supporting curved surface section for rolling cooperation with an air spring bag skin and an upper buckling section for fixed connection with a lower end of the bag skin from the axial direction, a center inner hole for the axial penetration of a piston rod of a shock absorber is arranged in the center of the piston body, a grease storage part and a gas seal part are arranged on the inner wall of the center inner hole, the grease storage part is used for storing lubricating grease to lubricate the relative movement surface between the piston rod and the piston body, the gas seal part is in interference fit with the piston rod of the shock absorber and is used for realizing the radial dynamic sealing between the heave piston and the piston rod. When the lubricating grease is gradually consumed, the lubricating grease in the grease storage part can be applied on the relative movement surface between the piston rod and the piston body, so that the problem of sealing failure caused by the consumption of the lubricating grease is solved.

Description

Technical Field

[0001] This invention relates to the field of air springs, and more particularly to an undulating piston for an air spring and an air spring. Background Technology

[0002] In modern automotive suspension systems, air springs are widely used to dampen shocks, stabilize vehicle performance, and improve ride comfort. Air springs effectively cushion external vibrations through the compression and expansion of air, providing a smoother ride. One of the core components of an air spring is the pulsating piston, which adjusts the spring's stiffness and function by changing the internal compressed air.

[0003] Relevant technology can be found in Chinese invention patent CN120557311A, which discloses an air spring support assembly and an air spring, including a shock absorber, a plane bearing, an upper friction-damping ring, a lower friction-damping ring, an air seal, and a locking nut. The plane bearing is positioned between the top surface of the shock absorber cylinder and the undulating piston on the air spring. An upper friction-damping ring is positioned between the top side of the shock absorber cylinder and the undulating piston on the air spring. A lower friction-damping ring is positioned between the bottom of the undulating piston on the air spring and the side of the cylinder. An air seal is positioned between the piston rod of the shock absorber and the undulating piston on the air spring and is locked by a locking nut. The air seal is existing technology, and common types include rubber O-rings, star-shaped rings (PTFE rings), and combined sealing rings. Lubricant is applied to the surface of the air seal and the piston rod of the shock absorber to reduce friction and wear between the air seal and the piston rod during movement, thereby improving the service life and operational stability of the air spring.

[0004] Regarding the aforementioned technologies, during the reciprocating motion of the piston rod, a small amount of grease will be carried out of the sealing area, leading to the gradual consumption of grease. At the same time, affected by the operating temperature, the base oil of the grease will evaporate and dry out, causing the lubrication state of the sealing contact surface to gradually deteriorate, ultimately resulting in increased frictional resistance, intensified dry friction of the sealing ring, and thus premature seal failure. Summary of the Invention

[0005] To address the problem of seal failure caused by grease loss, this invention provides an undulating piston for an air spring and an air spring.

[0006] In a first aspect, the fluctuating piston for an air spring provided by the present invention adopts the following technical solution: An undulating piston for an air spring includes a piston body. The piston body has, in the axial direction, a lower mounting section, a supporting curved surface section for rolling engagement with the air spring bladder, and an upper clamping section for fixed connection with the lower end of the bladder. The piston body has a central inner hole through which the piston rod of a shock absorber passes axially. A grease reservoir and an air seal are provided on the inner wall of the central inner hole. The grease reservoir stores grease to lubricate the relative moving surfaces between the piston rod and the piston body. The air seal is interference-fitted with the piston rod of the shock absorber to achieve a radial dynamic seal between the undulating piston and the piston rod.

[0007] Preferably, an mounting ring is detachably connected to the inner wall of the central inner hole, and the grease storage component includes a grease storage groove formed on the inner wall of the mounting ring. A sealing component is provided at the opening of the grease storage groove. The sealing component is connected to the air seal component. When the friction between the air seal component and the piston rod increases, the sealing component opens.

[0008] Preferably, the air seal component includes two air seals fixedly connected to the inner wall of the mounting ring, with the two air seals located on the upper and lower sides of the grease reservoir, respectively.

[0009] Preferably, the sealing component includes two sealing rings, which are respectively fixedly connected to the air seal and spliced ​​together to seal the grease reservoir.

[0010] Preferably, a support ring is fixedly connected to the inner wall of the central inner hole, a pressure ring is threaded into the central inner hole, the mounting ring is located between the support ring and the pressure ring, and both sides of the mounting ring are in contact with the support ring and the pressure ring, respectively.

[0011] Preferably, a plurality of limiting posts are fixedly connected to the lower pressure ring, and a plurality of limiting holes are provided on the mounting ring for the limiting posts to be inserted.

[0012] Preferably, an annular gasket that contacts the shock absorber is fixedly connected to the bottom of the central inner hole, and a sealing ring that contacts the piston rod of the shock absorber is integrally formed on the annular gasket.

[0013] Preferably, the upper clamping section has an annular fixing groove for clamping the lower end of the sac skin, and a first annular rib is fixedly connected to the top of the inner wall of the outer ring of the annular fixing groove.

[0014] Preferably, a plurality of second annular ribs are fixedly connected to the outer peripheral surface of the supporting curved surface segment.

[0015] Secondly, the air spring provided by the present invention adopts the following technical solution: An air spring includes an undulating piston for the air spring, a bladder, and a shock absorber.

[0016] In summary, the present invention has at least the following beneficial technical effects: 1. As the grease gradually wears down, the grease in the grease reservoir can be applied to the relative moving surfaces between the piston rod and the piston body, and the air seal component can scrape the excess grease back into the grease reservoir, avoiding waste and solving the problem of seal failure caused by grease wear. 2. As the grease is gradually depleted, the friction between the air seal component and the piston rod gradually increases. When the preset threshold is reached, the sealing component opens, and the grease in the grease reservoir flows out and is applied to the relative moving surface between the piston rod and the piston body through the air seal component. When the grease in the grease reservoir is used up, the mounting ring can be disassembled and replaced with a new mounting ring without discarding the entire air spring, thus avoiding resource waste. 3. When grease overflows, both the upper and lower air seals can scrape the excess grease back into the grease reservoir, preventing the grease from escaping to various places. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the air spring according to an embodiment of the present invention.

[0018] Figure 2 This is a bottom view of the air spring according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the structure of the shock absorber according to an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the piston body according to an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of the fluctuating piston according to an embodiment of the present invention.

[0022] Figure 6 This is a cross-sectional structural diagram of the piston body according to an embodiment of the present invention.

[0023] Figure 7 This is a schematic diagram of the mounting ring structure according to an embodiment of the present invention.

[0024] Figure 8 This is a schematic diagram of the gas seal structure according to an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached drawings: 1. Piston body; 11. Lower mounting section; 12. Support curved surface section; 121. Second annular rib; 13. Upper pressing section; 131. First annular rib; 14. Central inner hole; 15. Support ring; 16. Lower pressing ring; 17. Limiting post; 18. Annular gasket; 2. Blade; 3. Shock absorber; 31. Piston rod; 4. Mounting ring; 41. Grease reservoir; 42. Air seal; 43. Sealing ring; 44. Positioning ring. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1 -Appendix Figure 8 The present invention will be described in further detail below.

[0027] This invention discloses an undulating piston for an air spring and an air spring. (See reference...) Figures 1 to 4 The undulating piston for the air spring includes a piston body 1, which is injection molded. The piston body 1 has, in sequence along the axial direction, a lower mounting section 11, a support curved surface section 12 for rolling engagement with the air spring bladder 2, and an upper clamping section 13 for fixed connection with the lower end of the bladder 2. The piston body 1 has a central inner hole 14 through which the piston rod 31 of the shock absorber 3 passes axially. A grease reservoir and an air seal are provided on the inner wall of the central inner hole 14. The grease reservoir stores grease to lubricate the relative moving surfaces between the piston rod 31 and the piston body 1. The air seal is interference-fitted with the piston rod 31 of the shock absorber 3 to achieve a radial dynamic seal between the undulating piston and the piston rod 31. When the grease is gradually depleted, the grease in the grease reservoir can be applied to the relative moving surfaces between the piston rod 31 and the piston body 1, and the air seal can scrape excess grease back into the grease reservoir, avoiding waste and solving the problem of seal failure caused by grease depletion.

[0028] Reference Figures 4 to 7 A mounting ring 4 is detachably connected to the inner wall of the central inner hole 14. The grease storage component includes a grease storage groove 41 formed on the inner wall of the mounting ring 4. A sealing component is provided at the opening of the grease storage groove 41, and the sealing component is connected to the air seal component. When the friction between the air seal component and the piston rod 31 increases, the sealing component opens. As the grease gradually depletes, the friction between the air seal component and the piston rod 31 gradually increases. When a preset threshold is reached, the sealing component opens, and the grease in the grease storage groove 41 flows out and is applied to the relative moving surface between the piston rod 31 and the piston body 1 through the air seal component. When the grease in the grease storage groove 41 is used up, the mounting ring 4 can be disassembled and replaced with a new mounting ring 4 without discarding the entire air spring, thus avoiding resource waste. The preset threshold is preset by those skilled in the art based on actual working conditions.

[0029] Reference Figures 2 to 7The gas seal component includes two gas seals 42 fixedly connected to the inner wall of the mounting ring 4. The two gas seals 42 are located on the upper and lower sides of the grease reservoir 41, respectively. When grease overflows, both upper and lower gas seals 42 can scrape the excess grease back into the grease reservoir component, preventing the grease from escaping to other places. At the same time, after the mounting ring 4 is removed, the integrated grease reservoir 41 can be directly replenished with grease and the gas seal component can be replaced without disassembling the piston body 1, bladder 2 and shock absorber 3 and other components, making maintenance convenient. The gas seal 42 can be a rubber O-ring, a star ring (PTFE ring), or any sealing structure used in actual use.

[0030] Reference Figures 3 to 7 The sealing component includes two sealing rings 43, which are fixedly connected to the air seal 42. The two sealing rings 43 are spliced ​​together to seal the grease reservoir 41. When the grease is gradually consumed, the friction between the air seal component and the piston rod 31 gradually increases. The piston rod 31 drives the air seal 42 to move more. The air seal 42 drives the two sealing rings 43 away from each other, and the grease can overflow.

[0031] A support ring 15 is fixedly connected to the inner wall of the central inner hole 14, and a pressure ring 16 is threaded into the central inner hole 14. The mounting ring 4 is located between the support ring 15 and the pressure ring 16, and both sides of the mounting ring 4 are in contact with the support ring 15 and the pressure ring 16 respectively. By rotating the pressure ring 16, the pressure ring 16 can be removed from the central inner hole 14, thereby facilitating the removal of the mounting ring 4.

[0032] Multiple limiting posts 17 are fixedly connected to the pressure ring 16. Multiple limiting holes are provided on the mounting ring 4 for the limiting posts 17 to be inserted into, so as to prevent the mounting ring 4 from shifting in the central inner hole 14. An elastic block is fixedly connected to the limiting post 17. A slot is provided on the limiting hole to cooperate with the elastic block, so as to facilitate the positioning of the mounting ring 4.

[0033] The bottom of the mounting ring 4 is fixedly connected to a positioning ring 44, and an annular positioning groove is provided above the support ring 15 for the positioning ring 44 to be placed, further preventing the mounting ring 4 from shifting in the central inner hole 14.

[0034] Reference Figure 4 An annular gasket 18 is fixedly connected to the bottom of the central inner hole 14 and contacts the shock absorber 3. A sealing ring is integrally formed on the annular gasket 18 and contacts the piston rod 31 of the shock absorber 3; further sealing the gap between the central inner hole 14 and the piston rod 31 of the shock absorber 3.

[0035] The upper clamping section 13 has an annular fixing groove for clamping the lower end of the skin 2. The top of the inner wall of the outer ring of the annular fixing groove is fixedly connected to a first annular rib 131. The first annular rib 131 can limit the lower end of the skin 2, thereby improving the stability of the connection between the skin 2 and the upper clamping section 13.

[0036] Multiple second annular ribs 121 are fixedly connected to the outer circumference of the supporting curved surface segment 12, which increases the strength of the supporting curved surface segment 12.

[0037] Reference Figures 1 to 3 An air spring includes an air spring undulating piston, a bladder 2, a shock absorber 3, and a roof plate connected to a vehicle. The bottom of the shock absorber 3 is connected to the suspension, the piston rod 31 of the shock absorber 3 is connected to the roof plate, the air spring undulating piston is bolted to the mounting seat on the shock absorber 3, the lower end of the bladder 2 is connected to the upper clamping section 13, and the upper end of the bladder 2 is connected to the roof plate.

[0038] In another embodiment, the grease reservoir 41 can be configured as an annular groove structure, evenly distributed circumferentially along the inner wall of the mounting ring 4. The cross-sectional shape of the grease reservoir 41 can be rectangular or trapezoidal. The volume of the grease reservoir 41 is designed according to the operating conditions to ensure sufficient grease is provided during the normal wear cycle of the air seal 42. The grease reservoir 41 can be pre-filled with lithium-based grease with a base oil viscosity of 150–220 cSt. This grease has excellent water resistance, oxidation resistance, and wide temperature range performance. It maintains stable lubrication performance within a temperature range of 40°C to 120°C, adapting to the actual working environment of automotive suspension systems.

[0039] In another embodiment, the sealing ring 43 can be made of polytetrafluoroethylene (PTFE) or oil-resistant rubber, and its inner contact surface is provided with micro-radial grooves. Under normal sealing conditions, the splicing surfaces of the two sealing rings 43 are kept tightly fitted by the elastic force of the air seal 42, achieving a reliable seal on the grease reservoir 41. When the frictional force between the air seal 42 and the piston rod 31 exceeds a preset threshold, the piston rod 31 drives the air seal 42 to generate axial displacement during relative movement. The air seal 42 transmits this displacement to the sealing ring 43 through its connection with the sealing ring 43. Under the action of axial force, the two sealing rings 43 separate from each other, and the grease in the grease reservoir 41 slowly seeps out along the micro-radial grooves on the inner side of the sealing ring 43, and is evenly coated on the surface of the piston rod 31, so that the coefficient of friction is quickly reduced to the normal range. The sealing ring 43 then resets and closes, realizing automatic adjustment of the grease supply.

[0040] In another embodiment, the disassembly and assembly method of the mounting ring 4 can be further optimized. The outer circumferential surface of the pressure ring 16 is provided with a wrench mating groove. Maintenance personnel can use a special wrench to rotate the pressure ring 16 and pull it out downward along the internal thread of the central inner hole 14. After the pressure ring 16 is removed, the mounting ring 4 can be removed downward because it loses its axial restraint. After replacing the new mounting ring 4, the pressure ring 16 is screwed back in to the specified torque to complete the installation. The entire replacement process does not require disassembly of major components such as the bladder skin 2, shock absorber 3, and top plate. The maintenance time per operation is significantly shortened compared to the traditional method, effectively reducing the maintenance cost throughout the entire life cycle.

[0041] In another embodiment, the engagement between the limiting post 17 and the limiting hole of the mounting ring 4 can be further designed as a quick-connect positioning structure. The top of the limiting post 17 has a spherical protrusion, and the entrance of the limiting hole has a tapered guide surface that matches the spherical protrusion. When the mounting ring 4 is inserted, the spherical protrusion automatically aligns along the guide surface and engages with the slot in the limiting hole, achieving tool-free quick positioning. During disassembly, by pushing the mounting ring 4 axially downwards, the spherical protrusion is compressed, causing its elastic base to disengage from the slot, allowing the mounting ring 4 to be easily removed. This quick-connect positioning structure improves the reliability of the mounting ring 4's positioning and simplifies maintenance procedures.

[0042] In another embodiment, the cross-sectional shape of the second annular rib 121 can be semi-circular or triangular, and the spacing between two adjacent second annular ribs 121 is set to 5–15 mm. This allows the second annular rib 121 to form multi-point line contact with the inner wall of the bladder 2 when the bladder 2 rolls on the supporting curved section 12, effectively limiting the axial movement of the bladder 2 and improving the guiding accuracy of the bladder 2. At the same time, the second annular rib 121 can evenly distribute the radial pressure of the bladder 2 on the supporting curved section 12, reducing local stress concentration and extending the service life of the supporting curved section 12. The material of the second annular rib 121 is integrally injection molded with the piston body 1, and its surface is sandblasted, with the friction coefficient controlled within the range of 0.15–0.25, balancing the guiding effect on the bladder 2 and the need to reduce the wear of the bladder 2.

[0043] In another embodiment, the annular gasket 18 is fixedly connected to the bottom of the central inner hole 14 by an interference fit. An interference of 0.02–0.05 mm is provided between the outer cylindrical surface of the annular gasket 18 and the bottom stepped surface of the central inner hole 14 to ensure that the annular gasket 18 does not loosen or fall off under vehicle vibration and temperature changes. The lip of the integrally formed sealing ring on the annular gasket 18 has an interference of 0.1–0.3 mm with the piston rod 31 of the shock absorber 3. The lip adopts a double-lip structure, with the outer lip for dust prevention and the inner lip for sealing, effectively preventing external moisture and dust from intruding through the gap between the piston rod 31 and the central inner hole 14, further improving the overall sealing performance and reliability.

[0044] In another embodiment, the fit between the first annular rib 131 on the upper clamping section 13 and the annular fixing groove can be further refined. The cross-section of the first annular rib 131 is an isosceles trapezoid with an upper inclined angle of 30–45° and a lower inclined angle of 60–75°. During installation, the lower end of the air spring 2 is guided smoothly into the annular fixing groove along the upper inclined surface. After the elastic deformation of the air spring 2 material passes over the first annular rib 131, it recovers and is locked by the lower inclined surface of the first annular rib 131. During vehicle operation, when the air spring 2 is subjected to axial pull-out force, the lower inclined surface of the first annular rib 131 forms a barrier, effectively preventing the air spring 2 from coming off the upper clamping section 13, thus improving the overall safety and reliability of the air spring. The groove depth of the annular fixing groove is designed to be 1.2–1.5 times the wall thickness of the lower end of the air spring 2, ensuring that the lower end of the air spring 2 is completely embedded in the fixing groove, increasing the contact area and further improving the connection strength.

[0045] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A undulating piston for an air spring, comprising a piston body (1), wherein the piston body (1) is provided sequentially in the axial direction as a lower mounting section (11), a supporting curved surface section (12) for rolling engagement with an air spring bladder (2), and an upper clamping section (13) for fixed connection with the lower end of the bladder (2), wherein the piston body (1) is provided with a central inner hole (14) through which the piston rod (31) of a shock absorber (3) passes axially, characterized in that: A grease storage component and an air seal component are provided on the inner wall of the central inner hole (14). The grease storage component is used to store grease to lubricate the relative moving surface between the piston rod (31) and the piston body (1). The air seal component is interference-fitted with the piston rod (31) of the shock absorber (3) to achieve radial dynamic sealing between the undulating piston and the piston rod (31).

2. The undulating piston for an air spring according to claim 1, characterized in that: An installation ring (4) is detachably connected to the inner wall of the central inner hole (14). The grease storage component includes a grease storage groove (41) opened on the inner wall of the installation ring (4). A sealing component is provided at the opening of the grease storage groove (41). The sealing component is connected to the air seal component. When the friction between the air seal component and the piston rod (31) increases, the sealing component opens.

3. The undulating piston for an air spring according to claim 2, characterized in that: The air seal component includes two air seals (42) fixedly connected to the inner wall of the mounting ring (4), and the two air seals (42) are located on the upper and lower sides of the grease reservoir (41), respectively.

4. The undulating piston for an air spring according to claim 3, characterized in that: The sealing component includes two sealing rings (43), which are fixedly connected to the air seal (42) respectively. The two sealing rings (43) are spliced ​​together to seal the grease reservoir (41).

5. The undulating piston for an air spring according to claim 2, characterized in that: A support ring (15) is fixedly connected to the inner wall of the central inner hole (14), and a pressure ring (16) is threaded into the central inner hole (14). The mounting ring (4) is located between the support ring (15) and the pressure ring (16), and the two sides of the mounting ring (4) are in contact with the support ring (15) and the pressure ring (16) respectively.

6. The undulating piston for an air spring according to claim 5, characterized in that: Multiple limiting posts (17) are fixedly connected to the pressure ring (16), and multiple limiting holes are provided on the mounting ring (4) for the limiting posts (17) to be inserted.

7. The undulating piston for an air spring according to claim 1, characterized in that: The bottom of the central inner hole (14) is fixedly connected to an annular gasket (18) that contacts the shock absorber (3), and a sealing ring that contacts the piston rod (31) of the shock absorber (3) is integrally formed on the annular gasket (18).

8. The undulating piston for an air spring according to claim 1, characterized in that: The upper clamping section (13) is provided with an annular fixing groove for clamping the lower end of the bladder skin (2), and the top of the inner wall of the outer ring of the annular fixing groove is fixedly connected with a first annular rib (131).

9. The undulating piston for an air spring according to claim 1, characterized in that: Multiple second annular ribs (121) are fixedly connected to the outer circumferential surface of the supporting curved surface segment (12).

10. An air spring, characterized in that, Includes the undulating piston, bladder (2), and shock absorber (3) for air springs as described in any one of claims 1-9.

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