Patent Application
20210332867
The present invention generally relates to an air suspension assembly.
Air suspension assemblies are often used in the axle/suspension systems of a vehicle. They can also be used in other applications, such as, for example, cushioning the cab of a vehicle. Typically, the air suspension assemblies utilize boots to cushion the ride, dampen vibrations, and stabilize the vehicle. The air sleeve, operating as a rolling lobe, is ordinarily made of rubber and cords so that the air sleeve has a high enough strength to maintain air pressure inside the air sleeve. The use of an air sleeve requires a costly rubber-forming process and typically requires great air pressure to support it. Reinforcing cords are required and often an additional restraining cylinder is required to withstand this pressure.
One such an air suspension assembly is disclosed in U.S. Pat. No. 10,618,366. The air suspension assembly comprises a top and a bottom disposed on a center axis and spaced apart from one another. A bellows of an elastomeric material extends between a first end secured to the top and a second end secured to the bottom defining a chamber. The chamber extends between the top, the bottom, and the bellows for containing pressurized air, whereby a pressure of the pressurized air is controlled based on a force applied. The bellows has an interior surface and an exterior surface and including a plurality of convolutes extending between the first end and the second end.
The present invention provides for an air suspension assembly that is simple and cost-effective by replacing the rubber bellows previously used in other air suspension assemblies with a robust thermoplastic elastomer bellows. In addition, the invention also provides a simple and cost-effective manufacturing process of forming the bellows. Furthermore, the invention provides cost reduction by requiring a lower-power compressor to support the bellows.
It is one aspect of the present invention to provide an air suspension assembly. The air suspension assembly comprises a top and a bottom disposed on a center axis and spaced apart from one another. A bellows of an elastomeric material extends between a first end secured to the top and a second end secured to the bottom defining a chamber. The chamber extends between the top, the bottom, and the bellows for containing pressurized air, whereby a pressure of the pressurized air is controlled based on a force applied. The bellows has an interior surface and an exterior surface and including a plurality of convolutes extending between the first end and the second end. Each convolute of the plurality of convolutes includes a pair of outer lobes and an inner lobe with each outer lobe of the pair of outer lobes having an outer lobe thickness extending between the interior surface and the exterior surface of the bellows.
It is another aspect of the present invention to provide an air suspension assembly. The air suspension assembly comprises a top and a bottom disposed on a center axis and spaced apart from one another. A piston is disposed on the center axis spaced from the top. A bellows extends about the center axis between a first end secured to the top and a second end secured to the bottom connecting the top and the bottom defining a chamber extending between the top, the bottom, and the bellows. The bellows having an interior surface and an exterior surface. The bellows includes a plurality of convolutes extending between the first end and the second end. The chamber contains pressurized air in fluid communication with the piston. A pressure of the pressurized air is controlled based on a force applied to the air suspension assembly. A damper is connected to the piston and moveable between a compressed position and an undeformed position. A jounce bumper is connected to the top for absorbing energy of the damper when the air suspension assembly is compressed. The damper compresses the jounce bumper in the compressed position and the damper is spaced from the jounce bumper in the undeformed position.
It is another aspect of the present invention to provide a bellows of an air suspension assembly. The bellows comprises an interior surface and an exterior surface. A first end is secured to a top of the air suspension assembly. A second end is secured to a bottom of the air suspension assembly connecting the top and the bottom defining a chamber extending about a center axis between the top, the bottom, and the bellows. A plurality of convolutes extends between the first end and the second end. Each of the plurality of convolutes extends between a pair of outer lobes spaced from one another along the center axis. The outer lobe has an outer lobe thickness extending between the interior surface and the exterior surface of the bellows. An inner lobe disposed radially inwardly from the outer lobes and between the outer lobes. The inner lobe has an inner lobe thickness extending between the interior surface and the exterior surface of the bellows. The outer lobe thickness and the inner lobe thickness are approximately equivalent. A bridge portion extends between the inner lobe and each one of the pair of outer lobes. The bridge portion has a bridge portion thickness extending between the interior surface and the exterior surface of the bellows. Each of the outer lobe thickness and the inner lobe thickness is greater than the bridge portion thickness.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an air suspension assembly 20 constructed according to an embodiment of the present invention is generally shown in
The air suspension assembly 20, as generally shown in
The top 22 includes a plate 36, which may have a circular shape, disposed on the center axis A for securing the air suspension assembly 20 to the vehicle. A side wall 38 having a cylindrical shape extends perpendicularly outwardly from the plate 36, parallel to the center axis A, and radially inwardly towards the chamber 32. A base wall 40 extends radially inwardly from the side wall 38 toward the center axis A. The side wall 38 includes a plurality of first ridges 42, spaced from one another, extending outwardly from the side wall 38 and annularly about the side wall 38 in a perpendicular relationship with the center axis A to receive the first end 28 of the bellows 26. A first ring 44 having a circular shape is disposed on the bellows 26 at the first end 28 of the bellows 26 and extends annularly about the side wall 38 of the top 22 to secure the bellows 26 to the side wall 38 of the top 22. In other words, the first ring 44 sandwiches the first end 28 of the bellows 26 between the first ring 44 and the first ridges 42 of the side wall 38.
The base wall 40 defines a hole 46 having a circular shape and disposed on the center axis A. A piston rod guide 48 having a cylindrical shape extends annularly about the center axis A and through the hole 46. The piston rod guide 48 may form a first central channel (not shown) extending along the center axis A for receiving a piston rod 50. A sleeve 52 is secured to the side wall 38 and extends annularly along the center axis A into the chamber 32. An internal spring 54 of an elastomeric material (e.g. a versatile thermoplastic elastomer), having a generally frustroconical shape, extends along the center axis A and is connected to and extends from the sleeve 52 of the top 22 into the chamber 32. According to an embodiment of the present invention, the internal spring 54 can be made from a heat resilient and/or chemical resistant material, such as a thermalplastic elastomer sold under the trademark Hytrel by DuPont. In some embodiments, the material (for example, Hytrel by DuPont) and dimensions of the bellows 26 may allow the bellows to be formed by blow-molding, as opposed to typical complex and costly rubber-forming techniques. The internal spring 54 defines a second central channel 56, having a generally cylindrical shape, disposed in-line with the first central channel and extending along the center axis A along the length of the internal spring 54 for allowing the piston rod 50 to extend into the chamber 32. In some embodiments, the internal spring 54 is a jounce bumper and may be made of a compressible material to absorb the energy of the damper 34 when the air suspension assembly 20 is compressed.
The damper 34 includes a housing 58 and a cap 60, each having a cylindrical shape and extending along the center axis A. The housing 58 extends between a proximal end (not shown) and a distal end 62. The distal end 62 is located in the chamber 32. The proximal end is located outside of the chamber 32 for connecting the air suspension assembly 20 to the vehicle. The cap 60 is secured to the housing 58 at the distal end 62 to form a compartment 64 inside the housing 58. The cap 60 and the housing 58 define a third central channel 66 extending along the center axis A for receiving the piston rod 50. It should be appreciated that, in some embodiments, the damper 34 may be a hydraulic damper with hydraulic fluid disposed inside the compartment 64, and the piston rod 50 may include a hydraulic piston 67 disposed inside the compartment 64 for interacting with the hydraulic fluid. The piston rod 50 and the hydraulic piston 67 are movable between a compression stroke and a rebound stroke. During the compression stroke, the piston rod 50 and the hydraulic piston 67 move axially away from the cap 60. During the rebound stroke, the piston rod 50 and the hydraulic piston 67 move axially toward the cap 60.
The housing 58 further defines two sets of bores 68, 70, including a first set of bores 68 and a second set of bores 70, axially spaced apart from one another. The first set of bores 68 is located adjacent the distal end 62 of the housing 58 and disposed about the center axis A. Each bore 68 of the first set of bores 68 is circumferentially spaced apart from adjacent bores of the first set of bores 68 for interacting with the cap 60. The cap 60 includes a plurality of protrusions 72 extending radially inwardly, wherein a protrusion 72 of the plurality of protrusions 72 is received in a bore of the first set of bores 68 to secure the cap 60 to the housing 58. The second set of bores 70 is located outside of the chamber 32 adjacent the bottom 24. The second set of bores 70 are spaced circumferentially from one another about the center axis A for interacting with the bottom 24.
The bottom 24 includes a body 74 extending annularly about the center axis A between the damper 34 and the bellows 26. The body 74 has a periphery 76 extending about the body 74. The body 74 includes a plurality of second ridges 78, axially spaced apart from one another, extending outwardly from the body 74 perpendicular to the center axis A for receiving the second end 30 of the bellows 26. A second ring 80 having a circular shape is disposed on the bellows 26 at the second end 30 of the bellows 26 and extending annularly about the body 74 of the bottom 24 to secure the bellows 26 to the body 74 of the bottom 24. In other words, the second end 30 of the bellows 26 is sandwiched between the second ring 80 and the second ridges 78 to secure the second end 30 of the bellows 26 to the bottom 24. The bottom 24 defines a fourth central channel 82 having a cylindrical shape disposed on the center axis A for receiving the damper 34. The bottom 24 further includes a collar portion 84 having a cylindrical shape extending along the center axis A for securing the bottom 24 to the damper 34. According to an embodiment of the present invention, the collar portion 84 may include at least one pin 86 extending radially inwardly toward the center axis A for engaging the second set of bores 70 of the housing 58 to secure the damper 34 to the bottom 24. It should be noted that the damper 34 can be secured to the bottom 24 using other ways, such as clamps, screws, or other well-known methods.
According to an embodiment of the present invention, the bellows 26 may have a varying bellows thickness T formed between an interior surface 88 disposed adjacent the chamber 32 and an exterior surface 90 disposed outside of the chamber 32. The bellows 26 has a series of convolutes 92, each having a generally sinusoidal-shaped (e.g., “W”-shaped) cross-section, extending between the first end 28 and the second end 30 to provide strength to the bellows 26 and to allow the bellows 26 to compress and retract. Referring now to
The outer lobe 93 has an exterior outer lobe radius R1 and an interior outer lobe radius R2, thereby defining an outer lobe thickness To extending between the exterior surface 90 and the interior surface 88. The inner lobe 94 has an exterior inner lobe radius R3 and an interior inner lobe radius R4, thereby defining an inner lobe thickness TI extending between the interior surface 88 and the exterior surface 90. As illustrated, the outer lobe thickness TO may vary along the profile of the outer lobe 93 with the outer lobe thickness TO being the greatest at an outer tip 98 of the outer lobe 93. The inner lobe 94 thickness may also vary along the profile of the inner lobe 94 with the inner lobe thickness TI being the greatest at an inner tip 100 of the inner lobe 94. The bridge portion 96 has a bridge portion thickness TB extending between the interior surface 88 and the exterior surface 90. Each convolute 92 has a height H extending between the outer lobes 93 and a width W extending between the outer diameter DO and the inner diameter DI. The inner lobe 94 is disposed along a mid-plane M of the convolute 92, which may be roughly half of the height H. It should be appreciated that the bridge portion 96 may have a slight radius of curvature (i.e., a bridge portion exterior radius and a bridge portion interior radius) between the outer lobe 93 and the inner lobe 94, or may be have a generally linear profile. According to an embodiment of the present invention, the bellows 26 may include about 16 convolutes extending between the first end 28 and the second end 30 of the bellows 26. It should be appreciated that, in some embodiments of the present invention, the bellows 26 may be molded to or fastened to a hardened sleeve portion disposed amid the convolutes 92 or between the plurality of convolutes 92 and the top 22 or the bottom 24 to provide additional structural integrity to the bellows 26.
In operation, the bottom 24, the damper 34, and the bellows 26 are moveable along the center axis A between an undeformed position, as illustrated in
The dimensions of the convolute 92 in the undeformed position, as illustrated in
In the undeformed position, the interior inner lobe radius R3 may be about 4.22 millimeters and extend about 30 degrees on one side of the mid-plane M and 30 degrees on the other side of the mid-plane M. In other words, interior inner lobe radius R3 may extend 2.13 mm on either side of the mid-plane M. The outer lobe thickness TO may vary across the profile of the outer lobe 93, but may be about at least about 6.13 millimeters. The inner lobe thickness TI may also vary across the profile of the inner lobe 94, but may be at least about 6.25 millimeters. The exterior surface 88 of the bridge portion 96 may extend at an angle of about 11 degrees relative to outer lobe 93 and the interior surface 90 of the bridge portion 96 may extend at an angle of about 8 degrees relative to the outer lobe 94. In other words, the bridge portion thickness TB may vary across the profile of the bridge portion 96. For example, the bridge portion thickness TB may increase between the outer lobe 93 and the inner lobe 94.
According to an embodiment of the present invention, a valve (not shown) may be disposed in fluid communication with the chamber for changing pressure in the chamber 32 (i.e., controlling pressurized air contained in the chamber 32) in response to a force applied to the air suspension assembly 20. By controlling a pressure of the pressurized air to the chamber 32 based on the force applied to the air suspension assembly 20, the bellows 26 may be stiffened and the thrust of the air spring may be adjusted. In some embodiments, the pressurized air in the chamber corresponds to a position of the bottom 24 relative to the top 22. For example, the valve may be configured to selectively apply between 0 and at least about 5 bars of air pressure to the chamber 32 to control the full range of the air suspension assembly 20. The strength of the bellows 26 due to the convolute 92 design may allow for the air suspension assembly 20 to function and be controlled with a lower-powered compressor. For example, the thickness, height, width, curvature, and number of convolutes 92 may provide resiliency to the air suspension assembly 20.
With reference to
Obviously, many modifications and variations of the present invention (for example as a standalone air spring assembly compare to the assembly described previously as being built around a damper) are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. The use of the word “said” in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word “the” precedes a word not meant to be included in the coverage of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202110217133.4 | Feb 2021 | CN | national |
This application claims the benefit of U.S. Provisional Application Patent Ser. No. 63/016,237, filed on Apr. 27, 2020, and Chinese Patent Application No. 202110217133.4 filed on Feb. 26, 2021, the entire disclosures of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63016237 | Apr 2020 | US |
