Single-piston membrane type air spring

Abstract

A single-piston membrane type air spring comprises a cylindrical shell of the air spring, an upper installation base and a piston, the upper installation base is used for being connected with a vehicle body, a fixing base is arranged at the lower end of the piston and used for being connected with a suspension swing arm, and a rubber air bag is arranged between the upper end of the piston and the upper installation base. One end of the rubber air bag is fixedly connected with the upper mounting seat, the other end of the rubber air bag is fixedly connected with the upper end of the piston, so that the lower part of a bag body of the rubber air bag surrounds the piston, the cylindrical shell is step-shaped and comprises a small-diameter section and a large-diameter section, and the inner diameter ratio of the large-diameter section to the small-diameter section is 1.05: 1-1.15: 1. The small-diameter section of the cylindrical shell is located at the lower end, the upper portion of the piston is located in the small-diameter section of the cylindrical shell, and the upper end of the piston is located at the transition portion of the small-diameter section and the large-diameter section of the cylindrical shell in the designed load state.

Description

Technical Field

[0001] The utility model relates to the field of air springs, and particularly to a single-piston diaphragm air spring. Background Art

[0002] In an automotive suspension system, diaphragm air springs are widely used in high-class buses, heavy trucks, and some special vehicles. They can effectively isolate vibrations and impacts caused by uneven road surfaces to provide a comfortable driving experience. At the same time, they can also automatically adjust the vehicle body height according to the vehicle's load condition to improve the vehicle's stability and passability.

[0003] If classified according to the number of pistons, diaphragm air springs generally include single-piston diaphragm air springs and double-piston rubber air springs. Among them, the single-piston diaphragm air spring has a relatively simple structure and lower cost, and is suitable for some application occasions with low requirements for elastic characteristics and sensitive to space and cost, such as the suspension system of small vehicles or some light mechanical equipment; while the double-piston rubber air spring has more precise and complex elastic characteristics and can flexibly adjust the stiffness according to different load and working condition requirements, and is commonly used in fields with high performance requirements such as heavy vehicles and large industrial equipment.

[0004] However, whether it is a single-piston diaphragm air spring or a double-piston rubber air spring, the cylinder serving as the air spring housing is a straight-column cylinder structure (straight tube shape). In the vibration state during vehicle driving, the piston compresses the rubber airbag as the suspension moves upward to form vibration damping. However, due to the relatively long piston of the single-piston diaphragm air spring, a certain yaw will occur when the piston moves upward. The greater the vibration during driving, the larger the yaw angle of the piston. Once the yaw angle reaches the upper limit, the upper end of the piston will collide with the air spring housing during large vibrations. Repeated collisions will cause the rubber airbag wall on the inner wall of the housing to be punctured, resulting in the failure of the air spring. Currently, there is no way to solve this problem of the single-piston diaphragm air spring, which seriously affects the service life of the single-piston diaphragm air spring. Summary of the Invention

[0005] The purpose of the utility model is to provide a single-piston diaphragm air spring in view of the corresponding deficiencies of the prior art. By setting the housing of the air spring as a stepped housing with a larger upper part and a smaller lower part, and extending the housing part that is prone to collide with the piston to the outside, the purpose of extending the service life of the single-piston diaphragm air spring can be achieved without changing the original design parameters of the piston. In this way, even if the yaw angle of the piston reaches its design upper limit, the piston will not collide with the air spring housing, fundamentally solving the problem that the rubber airbag of the traditional single-piston diaphragm air spring is easily punctured by the piston.

[0006] The object of the present utility model is achieved by the following solution: A single-piston diaphragm air spring, comprising a cylindrical housing of the air spring, an upper mounting seat, and a piston. The upper mounting seat is used to connect with the vehicle body. A fixed seat is arranged at the lower end of the piston, and this fixed seat is used to connect with the suspension swing arm. A rubber airbag is arranged between the upper end of the piston and the upper mounting seat. One end of the rubber airbag is fixedly connected with the upper mounting seat, and the other end of the rubber airbag is fixedly connected with the upper end of the piston, so that the lower part of the airbag body of the rubber airbag surrounds the piston. The cylindrical housing is in a stepped shape, including a small-diameter section and a large-diameter section. The inner diameter ratio of the large-diameter section to the small-diameter section is 1.05:1 to 1.15:1. The small-diameter section of the cylindrical housing is located at the lower end, and the upper part of the piston is located in the small-diameter section of the cylindrical housing. The upper end of the piston is at the transition part between the small-diameter section and the large-diameter section of the cylindrical housing under the design load state.

[0007] Preferably, the ratio of the axial length of the large-diameter section to the small-diameter section of the cylindrical housing is 1:1.5 to 1:3.

[0008] Preferably, the transition part between the large-diameter section and the small-diameter section is conical, and the cone angle θ of this transition part is 40 to 90 degrees.

[0009] Preferably, a chamfered necking is provided at the lower end of the cylindrical housing.

[0010] Preferably, the yaw angle of the piston is -16° to 16°.

[0011] Preferably, the piston is provided with a blind hole. The upper bladder skin of the rubber airbag is fixedly connected with the lower end of the upper mounting seat through a clamping ring, and the lower bladder skin of the rubber airbag is fixedly connected with the upper end of the piston through a clamping ring, so that the bladder skin of the rubber airbag is sealed with the blind hole of the piston to form the air chamber of this air spring.

[0012] Preferably, a support ring is arranged inside the rubber airbag, and this support ring makes the bladder skin of the rubber airbag abut against the inner wall of the cylindrical housing.

[0013] Preferably, a dust cover is arranged between the lower part of the cylindrical housing and the fixed seat.

[0014] Preferably, the material of the cylindrical housing is aluminum alloy or aluminum-magnesium alloy.

[0015] The beneficial effects of the present utility model are as follows:

[0016] The cylindrical shell is stepped, including a small-diameter section and a large-diameter section. The inner diameter ratio of the large-diameter section to the small-diameter section is 1.05:1 to 1.15:1. The small-diameter section of the cylindrical shell is located at the lower end. The upper part of the piston is located within the small-diameter section of the cylindrical shell. The upper end of the piston is at the transition part between the small-diameter section and the large-diameter section of the cylindrical shell under the design load condition. The ratio of the axial length of the large-diameter section to the small-diameter section of the cylindrical shell is 1:1.5 to 1:3. The transition part between the large-diameter section and the small-diameter section is conical, and the cone angle θ of this transition part is 40 to 90 degrees. The yaw angle of the piston is -16° to 16°.

[0017] Since the shell of the air spring housing is not a straight cylindrical structure with the same inner diameter at both the upper and lower ends, but a stepped housing with a larger upper part and a smaller lower part. In this way, even if the shape (including length) of the piston is designed strictly according to the requirements of the vertical stiffness of the air spring, the purpose of extending the service life of the single-piston diaphragm air spring can be achieved. During vehicle driving, even if the yaw angle of the piston reaches its design upper limit, the piston will not collide with the air spring housing, fundamentally solving the problem that the rubber airbag of the traditional single-piston diaphragm air spring is easily punctured by the piston.

[0018] A chamfered necking is provided at the lower end of the cylindrical shell to prevent the lower end of the shell from being too sharp and puncturing the dust cover during vehicle driving.

[0019] Glossary

[0020] Design load condition: Since once the air spring is installed in the predetermined position, the piston will be subjected to a certain external pressure, which is usually called the design load. The air spring is in the design load condition when the relative compression stroke of the air spring is zero. That is to say, when the air spring is in the design load condition, taking the position of the piston at this time as the relative zero point, when the piston is subjected to an additional pressure at the installation position, the displacement of the piston from the initial position (relative zero point) to the end position, that is, the relative compression stroke of the air spring (note: the additional external pressure received by the piston does not include the design load of the air spring). The "ultimate tensile displacement" in the present invention refers to the upper limit value of the relative compression stroke, and the "ultimate compression displacement" refers to the lower limit value of the relative compression stroke. The "vertical design stiffness" refers to the vertical stiffness of the air spring when it is in the design load condition. Brief Description of the Drawings

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the stepped housing of the present invention in the embodiment;

[0023] Figure 3Schematic diagram of the structure of a traditional single-piston diaphragm air spring in the prior art in the embodiment;

[0024] Figure 4 Schematic diagram of the straight cylindrical housing structure described in the prior art in the embodiment;

[0025] Figure 5 Schematic diagram of the installation of a traditional single-piston diaphragm air spring on a vehicle suspension in the embodiment;

[0026] Figure 6 Schematic diagram of the installation of the present invention on a vehicle suspension in the embodiment;;

[0027] Figure 7 Schematic diagram of the collision of a traditional single-piston diaphragm air spring during vehicle driving in the embodiment;

[0028] Figure 8 Schematic diagram of the present invention when its piston reaches the upper limit value of the yaw angle during vehicle driving in the embodiment. Detailed implementation manners

[0029] Such as Figures 1 to 2As shown in the figure, a single-piston diaphragm air spring includes a cylindrical housing 3 of the air spring, an upper mounting seat 1, and a piston 8. The material of the cylindrical housing 3 is aluminum alloy or aluminum-magnesium alloy. The upper mounting seat 1 is used to connect to the vehicle body. A fixed seat 5 is provided at the lower end of the piston 8, and this fixed seat 5 is used to connect to the suspension swing arm. A rubber airbag 2 is provided between the upper end of the piston 8 and the upper mounting seat 1. One end of the rubber airbag 2 is fixedly connected to the upper mounting seat 1, and the other end of the rubber airbag 2 is fixedly connected to the upper end of the piston 8, so that the lower part of the bladder of the rubber airbag 2 surrounds the piston 8. The piston 8 is provided with a blind hole 9. The bladder skin of the upper part of the rubber airbag 2 is fixedly connected to the lower end of the upper mounting seat 1 through a clamping ring 6, and the bladder skin of the lower part of the rubber airbag 2 is fixedly connected to the upper end of the piston 8 through a clamping ring 6, so that the bladder skin of the rubber airbag 2 is sealed with the blind hole 9 of the piston 8 to form the air chamber of the air spring. A support ring 7 is provided inside the rubber airbag 2, and this support ring 7 makes the bladder skin of the rubber airbag 2 abut against the inner wall of the cylindrical housing 3. The cylindrical housing 3 is stepped, including a small-diameter section 3a and a large-diameter section 3b. The inner diameter ratio of the large-diameter section 3b to the small-diameter section 3a is 1.05:1 to 1.15:1. The small-diameter section 3a of the cylindrical housing 3 is located at the lower end. The upper part of the piston 8 is located inside the small-diameter section 3a of the cylindrical housing 3, and the upper end of the piston 8 is at the transition part 3c between the small-diameter section 3a and the large-diameter section 3b of the cylindrical housing 3 under the design load condition. The axial length ratio of the large-diameter section 3b to the small-diameter section 3a of the cylindrical housing 3 is 1:1.5 to 1:3. The transition part 3c between the large-diameter section 3b and the small-diameter section 3a is conical, and the cone angle θ of this transition part 3c is 40 to 90 degrees. The yaw angle of the piston 8 is -16° to 16°. A chamfered necking 3d is provided at the lower end of the cylindrical housing 3. A dust cover 4 is provided between the lower part of the cylindrical housing 3 and the fixed seat 5. Both ends of this dust cover 4 are respectively mounted on the cylindrical housing 3 and the fixed seat 5 of the piston 8, and are used to protect the exposed moving part of the bladder skin.

[0030] As Figures 3 to 4 shown in the figure, the structure of a traditional single-piston diaphragm air spring also includes a cylindrical housing, an upper mounting seat 1, a rubber airbag 2, a dust cover 4, a fixed seat 5 (i.e., the flange for fixing the piston 8 on the suspension swing arm 300), a clamping ring 6, a support ring 7, a piston 8, and a blind hole 9. Different from the present invention, the cylindrical housing of the traditional single-piston diaphragm air spring is a straight cylindrical housing 10, and the inner diameters of the upper and lower ends of this straight cylindrical housing 10 are the same. A chamfered necking is also provided at the lower end of the straight cylindrical housing 10 to prevent the lower end from being too sharp.

[0031] The reciprocating, lateral, and yaw angle thresholds of this traditional single-piston diaphragm air spring are determined by the movement space of the piston and the housing. To meet the requirements of the suspension reciprocating motion, the length of the piston is generally designed to be very long. If the designed value of the yaw angle threshold of the piston is relatively large at this time, in the vibration state during vehicle driving, once the yaw angle of the piston reaches the upper limit, the upper end of the piston will collide with the air spring housing during large vibrations.

[0032] Through the improvement of the original straight cylindrical housing 10 of the present utility model, the housing of the air spring is set as a stepped housing with a larger upper part and a smaller lower part, and the housing part that was originally prone to collide with the piston is extended outward. Without changing the original design parameters of the piston, the purpose of extending the service life of the single-piston diaphragm air spring can be achieved. In this way, even if the yaw angle of the piston reaches its design upper limit, the piston will not collide with the air spring housing, fundamentally solving the problem that the rubber airbag of the traditional single-piston diaphragm air spring is easily punctured by the piston. When designing the single-piston diaphragm air spring using the structure described in the present utility model, the shape and length of the piston 8 are also designed strictly according to the vertical stiffness requirements. However, since the aluminum shell is designed as a stepped shape, the problem of "once the yaw angle of the piston reaches the upper limit during the vibration state of vehicle driving, it will cause the upper end of the piston to collide with the air spring housing during large vibrations" can be avoided.

[0033] As Figures 5 to 6 shown, the present utility model and the traditional single-piston diaphragm air spring are respectively installed at the same position of the vehicle suspension, and the shock absorber 100 is used to connect the vehicle body 200 and the suspension swing arm 300, so that the installation space between the vehicle body 200 and the suspension swing arm 300 is the same. The following comparative experiments are conducted using the present utility model and the traditional single-piston diaphragm air spring:

[0034] I. Experimental environment and design conditions

[0035] 1-1) The installation space height of the air spring is 281 mm, and the maximum installation diameter of the air spring is 170 mm;

[0036] 1-2) The design load is 12987 N, and the vertical design stiffness is 112 N / mm;

[0037] 1-3) The ultimate tensile displacement is 53.1 mm, and the ultimate compression displacement is -51.6 mm;

[0038] 1-4) The burst pressure is greater than 4 MPa;

[0039] II. Some design parameters of the traditional single-piston diaphragm air spring

[0040] 2-1) The piston length is 185 mm;

[0041] 2-2) The piston yaw threshold range is -16° to 16°;

[0042] 2-3) The inner diameter of the housing is 140 mm, and the wall thickness of the housing is 2.5 mm;

[0043] III. Partial design parameters of the present utility model (other parameters are designed in a conventional manner)

[0044] 3-1) The piston length is 185 mm;

[0045] 3-2) The piston yaw threshold range is -16° to 16°;

[0046] 3-3) The inner diameter of the small-diameter section 3a of the cylindrical housing 3 is 140 mm, the inner diameter of the large-diameter section 3b is 150 mm, and the inner diameter ratio of the large-diameter section 3b to the small-diameter section 3a is 1.07:1;

[0047] 3-4) The axial length of the large-diameter section 3b of the cylindrical housing 3 is 40 mm, and the axial length of the small-diameter section 3a is 76 mm. The axial length ratio of the large-diameter section 3b to the small-diameter section 3a of the cylindrical housing 3 is 1:1.9;

[0048] 3-5) The cone angle θ (i.e., the cone apex angle) of the transition part 3c between the large-diameter section 3b and the small-diameter section 3a of the cylindrical housing 3 is 74°;

[0049] 3-6) The wall thickness of the housing is 2.5 mm.

[0050] As Figures 7 to 8 shown, when the piston yaw angle of the traditional single-piston diaphragm air spring reaches 16°, the piston will collide with the bladder skin on the inner wall of the housing, while when the piston yaw angle of the present utility model reaches 16°, the piston will not collide with the bladder skin on the inner wall of the housing. Thus, it can be seen that under the same conditions, the service life of the present utility model is longer.

[0051] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. Any modifications made by those skilled in the art without departing from the spirit of the present utility model fall within the protection scope of the present utility model.

Claims

1. A single-piston diaphragm air spring, comprising a cylindrical housing (3) of the air spring, an upper mounting seat (1), and a piston (8). The upper mounting seat (1) is used for connecting with the vehicle body. A fixed seat (5) is arranged at the lower end of the piston (8), and the fixed seat (5) is used for connecting the suspension swing arm. A rubber airbag (2) is arranged between the upper end of the piston (8) and the upper mounting seat (1). One end of the rubber airbag (2) is fixedly connected with the upper mounting seat (1), and the other end of the rubber airbag (2) is fixedly connected with the upper end of the piston (8), so that the lower part of the airbag body of the rubber airbag (2) surrounds the piston (8). It is characterized in that, The cylindrical housing (3) is stepped and includes a small-diameter section (3a) and a large-diameter section (3b). The inner diameter ratio of the large-diameter section (3b) to the small-diameter section (3a) is 1.05:1 to 1.15:

1. The small-diameter section (3a) of the cylindrical housing (3) is located at the lower end. The upper part of the piston (8) is located within the small-diameter section (3a) of the cylindrical housing (3), and the upper end of the piston (8) is at the transition part (3c) between the small-diameter section (3a) and the large-diameter section (3b) of the cylindrical housing (3) under the design load condition.

2. The single-piston diaphragm air spring according to claim 1, characterized in that, The ratio of the axial length of the large-diameter section (3b) to the small-diameter section (3a) of the cylindrical housing (3) is 1:1.5 to 1:

3.

3. The single-piston diaphragm air spring according to claim 1, characterized in that, The transition part (3c) between the large-diameter section (3b) and the small-diameter section (3a) is conical, and the cone angle θ of this transition part (3c) is 40 to 90 degrees.

4. The single-piston diaphragm air spring according to claim 1, characterized in that, A chamfered necking (3d) is provided at the lower end of the cylindrical housing (3).

5. The single-piston diaphragm air spring according to claim 1, characterized in that, The yaw angle of the piston (8) is -16° to 16°.

6. The single-piston diaphragm air spring according to claim 1, characterized in that The piston (8) is provided with a blind hole (9). The upper skin of the rubber airbag (2) is fixedly connected to the lower end of the upper mounting seat (1) through a clamping ring (6), and the lower skin of the rubber airbag (2) is fixedly connected to the upper end of the piston (8) through a clamping ring (6), so that the skin of the rubber airbag (2) is sealed with the blind hole (9) of the piston (8) to form the air chamber of this air spring.

7. The single-piston diaphragm air spring according to claim 1, characterized in that, A support ring (7) is provided inside the rubber airbag (2), and this support ring (7) makes the skin of the rubber airbag (2) abut against the inner wall of the cylindrical housing (3).

8. The single-piston diaphragm air spring according to claim 1, wherein A dust cover (4) is provided between the lower part of the cylindrical housing (3) and the fixed seat (5).

9. The single-piston diaphragm air spring according to claim 1, characterized in that, The material of the cylindrical housing (3) is aluminum alloy or aluminum-magnesium alloy.

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