Air spring

Abstract

The invention belongs to the technical field of automobile suspensions, and particularly relates to an air spring which comprises a base, an air bag and a piston which are arranged from bottom to top, and an air containing cavity is defined by the base, the air bag and the piston. The piston is provided with a column cavity with a downward opening, a plunger in axial sliding sealing fit with the inner side wall of the piston is arranged in the column cavity, and the lower end of the plunger is connected to the base. The plunger divides the gas containing cavity into a main gas chamber and a compressed gas chamber, and the compressed gas chamber is located on the upper side of the top face of the plunger. The piston is provided with a first inflation inlet communicated with the main air chamber, a second inflation inlet communicated with the compression air chamber and an air outlet. And a one-way valve leading to the compressed air chamber is arranged on the second inflation port. Vehicle kinetic energy absorbed by the air spring is converted into telescopic motion of the plunger, power is provided for extracting gas from the compression gas chamber, compressing the gas in the compression gas chamber and conveying high-pressure gas out of the compression gas chamber, the high-pressure gas used by other devices is generated, and environment friendliness is achieved. Heat of the air spring is reduced, and service life of the air spring is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile suspension, and in particular relates to an air spring. Background Art

[0002] An air spring is a spring that uses compressed air as an elastic medium. Its working principle is to fill a sealed airbag with compressed air and use the compressibility of air to achieve elasticity. The up and down compression movement of the air spring absorbs the kinetic energy of the vehicle body to achieve vibration isolation and cushioning of the vehicle body, ensuring the driving comfort of the vehicle.

[0003] The existing air spring mainly includes a base, an airbag and a piston. The lower end of the airbag is sealed with the base, and the upper end of the airbag is sealed with the lower end of the piston. The base, airbag and piston form a closed air chamber. The base is connected to the wheel frame, and the piston is connected to the suspension. The air pump is used to inflate the air chamber in the airbag to adjust the stiffness of the air spring to meet the driving requirements of the vehicle on different road conditions and improve the driving comfort of the vehicle. When the vehicle vibrates up and down, the air spring converts the kinetic energy it absorbs into heat energy and discharges it into the air, resulting in energy waste. In addition, the heat dissipation process of the air spring will cause the air spring temperature to be high, accelerate the aging of the rubber airbag of the air spring, and shorten the life of the air spring. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an air spring which utilizes its own telescopic movement to convert the kinetic energy generated by the vibration of the vehicle body into the compression force of the compressed gas, thereby saving energy and protecting the environment, reducing the heat generated by the air spring, and extending the life of the air spring.

[0005] The technical solution adopted by the present invention to solve the technical problem is: an air spring, comprising a base, an airbag and a piston, wherein the base seals the lower port of the airbag, the piston seals the upper port of the airbag, and the base, the airbag and the piston form a closed gas chamber;

[0006] The piston has a column cavity with an opening facing downward, and a plunger is provided in the column cavity, which is axially slidably matched with the inner wall of the piston, and the plunger is sealed with the inner wall of the piston, and the lower end of the plunger is connected to the base; the plunger divides the gas chamber into a main gas chamber and a compression gas chamber isolated from each other, and the compression gas chamber is located on the upper side of the top surface of the plunger;

[0007] The piston is provided with a first charging port connected to the main air chamber, a second charging port connected to the compressed air chamber, and an air outlet connected to the compressed air chamber; the second charging port is provided with a one-way valve leading to the compressed air chamber.

[0008] Furthermore, the lower end of the piston is provided with an axial limiting portion which protrudes inwardly from the inner side wall of the piston.

[0009] Furthermore, the axial limiting portion is a ring plate structure integrally formed with the piston, and the axial limiting portion of the ring plate structure is coaxially arranged with the piston;

[0010] The piston comprises a piston cylinder with openings at both ends and a top plate welded on the upper part of the piston cylinder, the top plate seals the upper end of the piston cylinder, the top plate and the inner wall of the piston cylinder form a column cavity of the piston; the plunger is detachably connected to the base.

[0011] Furthermore, a limiting step is provided on the inner side wall of the upper portion of the piston cylinder, the top plate is located in the piston cylinder and the lower end surface of the top plate is in contact with the top surface of the limiting step.

[0012] Furthermore, the second air inlet is arranged on the top plate, and the second air inlet is covered with filter cotton;

[0013] The upper surface of the filter cotton is located below the upper end surface of the piston cylinder.

[0014] Furthermore, a buffer limiter is provided in the compressed air chamber, and the buffer limiter is located between the plunger and the top plate.

[0015] Furthermore, the one-way valve comprises a guide rod, an axial limit plate and a one-way valve plate arranged in the compressed air chamber;

[0016] The guide rod is parallel to the axis of the plunger, and the upper end of the guide rod is connected to the top plate; the axial limit plate is fixedly mounted on the lower end of the guide rod and is spaced apart from the top plate; the one-way valve plate is arranged between the axial limit plate and the top plate, and the one-way valve plate is mounted on the guide rod and axially slides with the guide rod.

[0017] Furthermore, the plunger comprises a plunger body, the outer side of the plunger body is provided with an annular groove coaxial therewith, a first sealing ring is provided in the annular groove, and the first sealing ring protrudes from the outer side of the plunger body and seals with the inner side wall of the piston;

[0018] The first sealing ring is provided with an annular portion which is integrally formed therewith and protrudes upward from the upper end surface of the plunger body, and the annular portion is the buffer limiter.

[0019] Furthermore, a connecting rod is provided in the main air chamber, the upper end of the connecting rod is hinged to the plunger through a universal ball head, and the lower end of the connecting rod is detachably connected to the base.

[0020] Furthermore, the base is provided with an axially penetrating limiting step hole, and the large hole of the limiting step hole is located on a side close to the main air chamber;

[0021] The lower part of the connecting rod is provided with a shaft ring integrally formed therewith, the upper hoop of the connecting rod below the shaft ring is provided with a second sealing ring, and the connecting rod below the second sealing ring is provided with a threaded section; the second sealing ring is in sealing cooperation with the connecting rod;

[0022] The connecting rod passes through the limiting step hole, the second sealing ring is sealed with the hole wall of the large hole of the limiting step hole, the shaft ring is axially abutted with the top surface of the base; the threaded section protrudes downward from the base and is connected to a fastening nut, and the upper end surface of the fastening nut is tightly fitted with the base.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: an air spring is provided, wherein a plunger is arranged in the column cavity of the piston and axially slides with the side wall thereof to form a compressed air chamber with adjustable volume, the kinetic energy of the vehicle absorbed by the air spring is used to drive the plunger to extend and retract to change the volume of the compressed air chamber, and a one-way valve is arranged on the second charging port connected to the compressed air chamber to control the opening and closing of the second charging port. That is, during the stretching movement of the air spring, the air pressure in the compressed air chamber is less than the external atmospheric pressure, and the one-way valve opens the second charging port; during the compression movement of the air spring, the air pressure in the compressed air chamber is greater than the external atmospheric pressure, the one-way valve closes the second charging port and compresses the gas in the compressed air chamber into high-pressure gas, and the high-pressure gas generated by the compression movement of the air spring is discharged from the gas outlet to other devices for application, which is green and environmentally friendly. In addition, the present invention converts the kinetic energy of the vehicle absorbed by the air spring into the extension and retraction movement of the plunger, and finally converts it into the power of extracting gas into the compressed air chamber, compressing and pressurizing the gas in the compressed air chamber, and transmitting high-pressure gas to the outside of the compressed air chamber, thereby reducing the heat generation of the air spring, slowing down the aging of the airbag, and extending the service life of the air spring. By setting an axial limiter at the lower end of the piston to limit the plunger axially, the plunger is prevented from slipping out of the piston column cavity, which facilitates the installation of the plunger and improves the reliability of the air spring. By setting a push rod hinged to the plunger through a universal ball head, the plunger and the piston can be deflected by a certain angle relative to the base to adapt to the displacement of the base and the piston during the expansion and contraction of the air spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the axial cross-sectional structure of the present invention;

[0025] Figure 2 yes Figure 1 A schematic diagram of the enlarged structure of the middle part A;

[0026] Figure 3 yes Figure 1 A schematic diagram of the enlarged structure of the middle B part;

[0027] Figure 4 yes Figure 1 The enlarged structural diagram of the middle C part;

[0028] Figure 5 It is a schematic diagram of the axial cross-sectional structure of the base;

[0029] Figure 6 It is a schematic diagram of the assembly structure of the connecting rod and the plunger;

[0030] Figure markings: 1-base; 11-annular portion; 12-installation cavity; 2-airbag; 3-piston; 31-first inflation port; 32-second inflation port; 33-air outlet; 34-axial limiting portion; 35-piston cylinder; 36-top plate; 37-limiting step; 38-filter cotton; 41-main air chamber; 42-compression air chamber; 43-buffer limiting member; 5-plunger; 51-plunger body; 52-first sealing ring; 6-connecting rod; 61-shaft ring; 62-second sealing ring; 63-threaded section; 64-fastening nut; 7-one-way valve; 71-guide rod; 72-axial limiting plate; 73-one-way valve plate. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] As attached Figure 1-6 As shown, an air spring comprises a base 1, an airbag 2 and a piston 3, wherein the base 1 seals the lower port of the airbag 2, and the piston 3 seals the upper port of the airbag 2, and the base 1, the airbag 2 and the piston 3 form a closed gas chamber; the piston 3 has a columnar cavity with an opening facing downward, and a plunger 5 is provided in the columnar cavity, which is axially slidably matched with the inner wall of the piston 3, and the plunger 5 is sealed with the inner wall of the piston 3, and the lower end of the plunger 5 is connected to the base 1; the plunger 5 divides the gas chamber into a main air chamber 41 and a compressed air chamber 42 isolated from each other, and the compressed air chamber 42 is located on the upper side of the top surface of the plunger 5; the piston 3 is provided with a first inflation port 31 connected to the main air chamber 41, a second inflation port 32 connected to the compressed air chamber 42, and an air outlet 33 connected to the compressed air chamber 42; the second inflation port 32 is provided with a one-way valve 7 leading to the compressed air chamber 42. The other gas chambers outside the compressed air chamber 42 are the main air chambers 41. The one-way valve 7 is used to control the opening and closing of the second inflation port 32.

[0033] The base 1 of the air spring is connected to the wheel frame, the piston 3 is connected to the suspension, and compressed gas is charged into the main air chamber 41 through the first air filling port 31 to meet the rigidity requirements of the vehicle. When the vehicle travels on an uneven road, the body and the suspension drive the entire air spring to expand and contract, causing the base 1 and the piston 3 to move relative to each other in the up and down directions. When the air spring is in tension, the base 1 and the piston 3 move away from each other. Relative to the piston 3, the base 1 drives the plunger 5 to move downward. The plunger 5 slides downward in the column cavity of the piston 3 to gradually increase the volume of the compressed air chamber 42, thereby making the air pressure in the compressed air chamber 42 lower than the external atmospheric pressure. Under the action of the air pressure difference, the one-way valve 7 opens while controlling the second inflation port 32 to open, and the external gas enters the compressed air chamber 42 through the second inflation port 32; when the air spring is in compression, the base 1 and the piston 3 move closer to each other. Relative to the piston 3, the base 1 drives the plunger 5 to move upward. The plunger 5 slides upward in the column cavity of the piston 3 to gradually squeeze the volume of the compressed air chamber 42 and the gas inside it. The gas pressure of the compressed air chamber 42 gradually increases, thereby making the air pressure in the compressed air chamber 42 higher than the air pressure of the external gas. Under the action of the high-pressure gas in the compressed air chamber 42, the one-way valve 7 closes and seals the second inflation port 32, and the high-pressure gas in the compressed air chamber 42 is discharged to other devices through the air outlet 33 for use, which is energy-saving and environmentally friendly. The present invention converts the kinetic energy of the vehicle absorbed by the air spring into the telescopic movement of the plunger 5, and finally into power for extracting gas into the compressed air chamber 42, pressurizing the gas in the compressed air chamber 42, and transmitting high-pressure gas outside the compressed air chamber 42, thereby reducing the heat generation of the air spring, slowing down the aging of the airbag, and extending the service life of the air spring.

[0034] The base 1 is used to seal the lower port of the airbag 2 and connect the air spring to the wheel frame. The base 1 can be a cylindrical structure with one end sealed, or a solid columnar structure. The piston 3 is used to seal the upper port of the airbag 2 and connect the air spring to the vehicle suspension. The airbag 2 is generally sleeved on the outer peripheral surface of the base 1 and the piston 3, and the airbag 2 and the base 1 can be sealed and matched, and the airbag 2 and the piston 3 can be sealed and matched by means of hoop connection, crimping, etc. The piston 3 can be an integral structure formed in one piece, or a combined structure assembled by a plate and a sleeve. The main air chamber 41 is used to contain compressed gas, and the stiffness of the entire air spring is adjusted by adjusting the pressure of the compressed gas in the main air chamber 41 of the air spring. The vehicle air pump inflates the main air chamber 41 through the first inflation port 31. The first inflation port 31 can be set on the outer side wall or top wall of the piston 3 and communicate with the main air chamber 41 through the air channel on the piston 3.

[0035] When the air spring stretching stroke is too large, the plunger 5 is easy to slip out of the lower port of the piston 3 and is difficult to reset, resulting in air spring failure. Preferably, the lower end of the piston 3 is provided with an axial limit portion 34 that protrudes inward from the inner side wall of the piston 3. The axial limit portion 34 axially limits the plunger 5 in the column cavity of the piston 3 to prevent the plunger 5 from falling out, thereby improving the reliability of the air spring. After the air spring is installed on the vehicle, a limit portion is provided on the vehicle suspension to prevent the plunger 5 from colliding with the axial limit portion 34.

[0036] The axial limiting portion 34 can be a plurality of protrusions distributed along the circumference of the piston 3, or a ring plate structure, which can be fastened to the piston 3 by bolts, latches and other connectors, or can be an integral structure formed integrally with the piston 3. As a further preferred embodiment, the axial limiting portion 34 is a ring plate structure formed integrally with the piston 3, and the axial limiting portion 34 of the ring plate structure is coaxially arranged with the piston 3. The reliability of the axial limiting portion 34 is improved, the structure is simple, and the processing is convenient. The piston 3 is integrally formed with the axial limiting portion 34, and the axial limiting portion 34 cannot be disassembled, resulting in that the plunger 5 cannot be loaded into the column cavity from the lower port of the piston 3. Therefore, the piston 3 includes a piston cylinder 35 with openings at both ends and a top plate 36 welded on the upper part of the piston cylinder 35, the top plate 36 seals the upper port of the piston cylinder 35, and the top plate 36 and the piston cylinder 35 surround the column cavity of the piston 3; the plunger 5 is detachably connected to the base 1. When assembling the air spring, first install the plunger 5 into the column cavity from the upper end of the piston 3, then let the plunger 5 pass through the lower end of the piston 3 and install it on the base 1, and finally seal and weld the top plate 35 on the piston 3.

[0037] The top plate 36 can be welded to the outside of the piston cylinder 35 or to the inside of the piston cylinder 35. Preferably, a limiting step 37 is provided on the inner side wall of the upper part of the piston cylinder 35, and the top plate 36 is located in the piston cylinder 35 and the lower end surface of the top plate 36 is in contact with the top surface of the limiting step 37. The limiting step 37 supports the top plate 36 to limit its axial position in the piston 3, thereby improving the assembly accuracy of the top plate 36 and reducing the volume deviation of the column cavity of the piston 3 and the compression air chamber 42.

[0038] The second air charging port 32 is the air inlet passage of the compressed air chamber 42, and the air outlet 33 is the output passage of the gas in the compressed air chamber 42. It should be ensured that the second air charging port 32 is always located above the limit position on the plunger 5. Specifically, the second air charging port 32 is arranged on the top plate 36. The second air charging port 32 can be a circular hole, a square hole, an annular hole or other structures. Preferably, the second air charging port 32 is covered with filter cotton 38 to prevent dust outside the air spring from entering the compressed air chamber 42. The filter cotton 38 can be bonded to the top plate 36, or it can be fixed to the top plate 36 by using structures such as anchor nails and bolts. The upper surface of the filter cotton 38 is located below the upper end surface of the piston cylinder 35 to prevent the filter cotton 38 from being covered by other structures, thereby ensuring that the second air charging port 32 is unobstructed when opened.

[0039] The one-way valve 7 on the second air filling port 32 is used to control the opening and closing of the second air filling port 32, so that the one-way valve 7 opens the second air filling port 32 when the plunger 5 moves downward, and closes the second air filling port 32 when the plunger 5 moves upward. Specifically, the one-way valve 7 includes a guide rod 71, an axial limit plate 72 and a one-way valve plate 73 arranged in the compressed air chamber 42; the guide rod 71 is parallel to the axis of the plunger 5, and the upper end of the guide rod 71 is connected to the top plate 36; the axial limit plate 72 is fixedly installed at the lower end of the guide rod 71 and is spaced apart from the top plate 36; the one-way valve plate 73 is arranged between the axial limit plate 72 and the top plate 36, and the one-way valve plate 73 is installed on the guide rod 71 and axially slides with the guide rod 71. During the upward compression movement of the plunger 5, the gas pressure in the compressed air chamber 42 is greater than the external atmospheric pressure, and the gas in the compressed air chamber 42 pushes the one-way valve plate 73 to slide upward so that the one-way valve plate 73 fits on the lower end surface of the top plate 36 to close the second inflation port 32; during the downward pull-down movement of the plunger 5, the gas pressure in the compressed air chamber 42 is less than the external atmospheric pressure, and the external gas pushes the one-way valve plate 73 to slide downward to reset so that the one-way valve plate 73 is spaced apart from the lower end surface of the top plate 36, and the second inflation port 32 is opened. The one-way valve plate 73 can be connected to the top plate 36 or the axial limit plate 72 through an elastic member, and the elastic member can be a rubber elastic member or a coil spring. The one-way valve plate 73 can be a rigid valve plate or an elastic valve plate. In order to prevent the second inflation port 32 from leaking when the plunger 5 squeezes the compression air chamber 42, it is necessary to ensure the flatness of the upper end surface of the rigid valve plate and the lower end surface of the top plate 36 so that the one-way valve plate 73 and the top plate 36 are sealed and matched, that is, the processing accuracy of the one-way valve plate 73 and the top plate 36 is required to be high, and the cost is also high. Therefore, the one-way valve plate 73 is preferably an elastic valve plate. When the plunger 5 squeezes the compression air chamber 42, the air pressure in the compression air chamber 42 will cause the elastic valve plate to elastically deform and cling to the top plate 36, thereby improving the sealing of the second inflation port 32. The guide rod 71 and the axial limit plate 72 can be an integral structure formed in one piece, or they can be independent parts. The guide rod 71 can be installed on the top plate 36 by welding, interference crimping or threaded connection. Specifically, the guide rod 71 is threadedly connected to the top plate 36, and the guide rod 71 and the axial limit plate 72 are an integral structure formed in one piece, which is convenient for the assembly, disassembly and replacement of the one-way valve plate 73.

[0040] The plunger 5 slides up and down in the column cavity of the piston 3 to adjust the volume and air pressure of the compressed air chamber 42, providing power for the input, pressurization and output of the gas in the compressed air chamber 42. In order to avoid bad road conditions, the air spring compression movement amplitude is too large, causing the plunger 5 to move to the upper limit position and rigidly collide with the top plate 36. Preferably, a buffer limiter 43 is provided in the compressed air chamber 42, and the buffer limiter 43 is located between the plunger 5 and the top plate 36. The buffer limiter 43 is used to limit the plunger 5 axially in the column cavity of the piston 3 to avoid the plunger body 5 and the inner top wall of the piston 3. The rigid collision improves the driving comfort of the vehicle. The buffer limiter 43 is an elastic member, which can be an elastic buffer member made of rubber or a coil spring. The buffer limiter 43 can be installed on the plunger 5, and can also be set at the top of the column cavity of the piston 3.

[0041] The plunger 5 can be an integral structure formed in one piece, or a combined structure assembled from multiple parts; it can be a rubber column structure, or a combined structure assembled from a skeleton and a rubber ring wrapped outside the skeleton. Preferably, the plunger 5 includes a plunger body 51, and the outer side surface of the plunger body 51 is provided with an annular groove coaxial therewith, and a first sealing ring 52 is provided in the annular groove. The first sealing ring 52 protrudes from the outer side surface of the plunger body 51 and seals with the inner side wall of the piston 3 to improve the airtightness of the compressed air chamber 42. As a further preference, the first sealing ring 52 is provided with an annular portion that is integrally formed therewith and protrudes upward from the upper end surface of the plunger body 51, and the annular portion is the buffer limiter 43, which simplifies the structure.

[0042] The plunger 5 can be vertically fixedly connected to the base 1, or can be hinged to the base 1; the plunger 5 can be directly connected to the base 1, or can be transferred to the base 1 through other connecting parts. Preferably, a connecting rod 6 is provided in the main air chamber 41, the upper end of the connecting rod 6 is hinged to the plunger 5 through a universal ball head, and the lower end of the connecting rod 6 is detachably connected to the base 1. The connecting rod 6 and the base 1 can be deflected at a certain angle relative to the plunger 5 to adapt to the relative deflection of the base 1 and the piston 3 during the telescopic movement of the air spring. The outer diameter of the connecting rod 6 should be smaller than the inner diameter of the axial limit portion 34 of the ring plate structure, so that it can be connected to the base 1 after passing through the column cavity of the piston 3 from top to bottom.

[0043] The connecting rod 6 and the base 1 can be connected by bolts or pins. Specifically, the base 1 is provided with an axially through-going limiting step hole, and the large hole of the limiting step hole is located on the side close to the main air chamber 41; the lower part of the connecting rod 6 is provided with a shaft collar 61 integrally formed therewith, and a second sealing ring 62 is provided on the connecting rod 6 below the shaft collar 61, and a threaded section 63 is provided on the connecting rod 6 below the second sealing ring 62; the second sealing ring 62 is sealed with the connecting rod 6; the connecting rod 6 passes through the limiting step hole, and the second sealing ring 62 is sealed with the hole wall of the large hole of the limiting step hole, and the shaft collar 61 is axially abutted with the top surface of the base 1; the threaded section 63 protrudes downward from the base 1 and is connected with a fastening nut 64, and the upper end surface of the fastening nut 64 is tightly fitted with the base 1. The outer diameter of the shaft collar 61 is larger than the aperture of the large hole 11 of the limiting step hole. The shaft ring 61 and the fastening nut 64 cooperate with each other to position and install the connecting rod 6 in the limiting step hole on the base 1 . The second sealing ring 62 is used to seal the gap between the limiting step hole and the connecting rod 6 to ensure the air tightness of the main air chamber 41 .

[0044] During installation, the connecting rod 6 is first connected to the plunger 5, and then the connecting rod 6 is inserted into the column cavity from the upper end of the piston 3. The connecting rod 6 passes through the column cavity of the piston 3 from top to bottom and drives the plunger 5 to enter the column cavity of the piston 3. The axial limiting portion 33 limits the plunger 3 in the column cavity of the piston 3. The lower end of the connecting rod 6 passes through the limiting step hole of the base 1 so that the shaft ring 61 abuts against the upper end surface of the base 1 to pre-position the connecting rod 6 axially, so that the second sealing ring 62 and the connecting rod 6 are sealed and matched, and the connecting rod 6 is positioned and installed on the base 1 by tightening the nut 64. Finally, the sealing top plate 34 is sealed and welded in the column cavity of the piston 3 to seal the compressed air chamber 42.

[0045] As a further preference, the base 1 is provided with a downwardly protruding annular portion 11, the annular portion 11 and the base 1 enclose a downwardly opening mounting cavity 12, the lower end of the threaded section 63 on the connecting rod 6 and the fastening nut 64 are both located in the mounting cavity 12. The connecting rod 6 and the fastening nut 64 are prevented from interfering with other structures outside the air spring.

[0046] The terms "upper", "lower", "top", "bottom", "inside" and "outside" in the present invention are relative positional relationships and cannot be understood as limitations on specific positions. The embodiments of this specific implementation are all preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An air spring, comprising a base (1), an airbag (2) and a piston (3), wherein the base (1) seals a lower end of the airbag (2), the piston (3) seals an upper end of the airbag (2), and the base (1), the airbag (2) and the piston (3) form a closed gas chamber; characterized in that: The piston (3) has a column cavity with an opening facing downward, and a plunger (5) is provided in the column cavity and is axially slidably matched with the inner wall of the piston (3). The plunger (5) is sealed with the inner wall of the piston (3), and the lower end of the plunger (5) is connected to the base (1); the plunger (5) divides the gas chamber into a main gas chamber (41) and a compressed gas chamber (42) that are isolated from each other, and the compressed gas chamber (42) is located on the upper side of the top surface of the plunger (5); The piston (3) is provided with a first inflation port (31) connected to the main air chamber (41), a second inflation port (32) connected to the compressed air chamber (42), and an air outlet (33) connected to the compressed air chamber (42); the second inflation port (32) is provided with a one-way valve (7) leading to the compressed air chamber (42).

2. The air spring according to claim 1, characterized in that: The lower end of the piston (3) is provided with an axial limiting portion (34) which protrudes inwardly from the inner side wall of the piston (3).

3. The air spring according to claim 2, characterized in that: The axial limiting portion (34) is a ring plate structure integrally formed with the piston (3), and the axial limiting portion (34) of the ring plate structure is coaxially arranged with the piston (3); The piston (3) comprises a piston cylinder (35) with openings at both ends and a top plate (36) welded to the upper part of the piston cylinder (35); the top plate (36) seals the upper end of the piston cylinder (35); the top plate (36) and the inner wall of the piston cylinder (35) form a column cavity of the piston (3); the plunger (5) is detachably connected to the base (1).

4. The air spring according to claim 3, characterized in that: A limiting step (37) is provided on the inner side wall of the upper portion of the piston cylinder (35); the top plate (36) is located in the piston cylinder (35) and the lower end surface of the top plate (36) is in contact with the top surface of the limiting step (37).

5. The air spring according to claim 4, characterized in that: The second air filling port (32) is arranged on the top plate (36), and the second air filling port (32) is covered with filter cotton (38); The upper surface of the filter cotton (38) is located below the upper end surface of the piston cylinder (35).

6. The air spring according to claim 3, characterized in that: A buffer stopper (43) is provided in the compression air chamber (42), and the buffer stopper (43) is located between the plunger (5) and the top plate (36).

7. The air spring according to claim 3, characterized in that: The one-way valve (7) comprises a guide rod (71), an axial limit plate (72) and a one-way valve plate (73) arranged in the compressed air chamber (42); The guide rod (71) is parallel to the axis of the plunger (5), and the upper end of the guide rod (71) is connected to the top plate (36); the axial limit plate (72) is fixedly mounted on the lower end of the guide rod (71) and is spaced apart from the top plate (36); the one-way valve plate (73) is arranged between the axial limit plate (72) and the top plate (36), and the one-way valve plate (73) is mounted on the guide rod (71) and is axially slidably matched with the guide rod (71).

8. The air spring according to claim 6, characterized in that: The plunger (5) comprises a plunger body (51), the outer side surface of the plunger body (51) is provided with an annular groove coaxial therewith, a first sealing ring (52) is provided in the annular groove, and the first sealing ring (52) protrudes from the outer side surface of the plunger body (51) and is in sealing cooperation with the inner side wall of the piston (3); The first sealing ring (52) is provided with an annular portion which is integrally formed therewith and protrudes upwards from the upper end surface of the plunger body (51); the annular portion is the buffer stopper (43).

9. The air spring according to any one of claims 1 to 8, characterized in that: A connecting rod (6) is provided in the main air chamber (41), the upper end of the connecting rod (6) is hinged to the plunger (5) via a universal ball head, and the lower end of the connecting rod (6) is detachably connected to the base (1).

10. The air spring according to claim 9, characterized in that: The base (1) is provided with an axially penetrating limiting step hole, wherein the large hole of the limiting step hole is located on a side close to the main air chamber (41); The lower part of the connecting rod (6) is provided with a shaft ring (61) integrally formed therewith, the upper hoop of the connecting rod (6) below the shaft ring (61) is provided with a second sealing ring (62), and the connecting rod (6) below the second sealing ring (62) is provided with a threaded section (63); the second sealing ring (62) is in sealing cooperation with the connecting rod (6); The connecting rod (6) passes through the limiting step hole, the second sealing ring (62) is sealed with the hole wall of the large hole of the limiting step hole, and the shaft ring (61) is axially abutted with the top surface of the base (1); the threaded section (63) protrudes downward from the base (1) and is connected to a fastening nut (64), and the upper end surface of the fastening nut (64) is tightly fitted with the base (1).

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