Patent Application
20240288047
This applications claims priority to Chinese Patent Application No. 202310181321.5, filed on Feb. 27, 2023, which is hereby incorporated by reference in its entirety.
The present invention generally relates to a damper assembly for a vehicle.
Damper assemblies are well known in the art for use in a vehicle. One such a damper assembly is disclosed in patent publication U.S. Pat. No. 5,706,920A which discloses a monotube damper assembly including a main tube disposed on a center axis and extending between a first end and a second end. The damper defines a fluid compartment between the first end and the second end for containing a working fluid. A main piston is slidably disposed in the fluid compartment dividing the fluid compartment into a rebound chamber and a compression chamber. A piston rod is disposed on the center axis extending along the center axis to a distal end and attached to the main piston for moving the main piston between a compression stroke and a rebound stroke.
Conventional, passive shock absorber valves offer a poor compromise between performance, safety and driving comfort. To improve this situation, active and semi-active suspensions are often proposed. They, however, require the use of additional sensors, ECUs and control algorithms, what makes them complicated and extremely expensive. For this reason, adaptive passive valves are becoming more and more popular and are desired by car manufacturers.
Various adaptive valve technologies provide damping characteristics that depend not only on damper velocity but also on excitation frequency. Such solutions allow to achieve high damping forces for low frequencies, related to body motions and low damping forces for high frequencies, related to vibrations of the wheels.
It is known in the art for damper assemblies to include a frequency-dependent valve assembly to provide the damper assembly with the ability to reduce the level of damping force for high frequency events to provide better comfort and road holding for occupants. However, known valve assemblies are generally expensive, complex and have limited capabilities for tuning. Furthermore, most existing frequency-dependent valves are configured as add-ons that are attached to an existing damper design. These add-on valves may significantly increase dead-length of a damper. Moreover, they often require drilling of additional, intersecting bypass holes, which is an expensive process that generates contaminants and can weakens portions of the damper, such as a valve tenon. Accordingly, an improved damper assembly is desired.
The present invention provides a damper assembly. The damper assembly includes a damper tube having a tubular shape extending along a center axis and defining a fluid compartment. The damper assembly also includes a piston attached to a damper rod and movable through the damper tube along the center axis and dividing the fluid compartment into a compression chamber and a rebound chamber, the piston including a piston body and a frequency-dependent (FD) valve. The piston body defines an intermediate chamber in fluid communication with the rebound chamber. The FD valve includes: an FD housing having a tubular shape surrounding an FD chamber, an FD slider disposed within the FD housing and dividing the FD chamber into an FD pressure chamber and an FD displacement chamber, an FD control stack configured to regulate fluid flow between the intermediate chamber and the FD pressure chamber, and an FD working disc configured to deflect together with the FD housing for regulating fluid flow between the rebound chamber and the compression chamber.
The present invention also provides a piston for a damper assembly. The piston includes a piston body that defines an intermediate chamber. The piston also includes a frequency-dependent (FD) valve. The FD valve includes: an FD housing having a tubular shape surrounding an FD chamber, an FD slider disposed within the FD housing and dividing the FD chamber into an FD pressure chamber and an FD displacement chamber, an FD control stack configured to regulate fluid flow between the intermediate chamber and the FD pressure chamber, and an FD working disc configured to deflect together with the FD housing for regulating fluid flow between a rebound chamber and a compression chamber.
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, it is one aspect of the present invention to provide a damper assembly 20, which may be used as a part of a suspension in a vehicle, such as a passenger car or truck. The damper assembly 20 of the present disclosure is shown as a monotube damper. However, the principles of the present disclosure may be used with other types of dampers, such as in a twin-tube damper.
The damper assembly 20 of the present disclosure provides a unique solution for the implementation of a frequency adaptive section within a piston valve assembly.
As generally shown in
The damper assembly 20 also includes a damper rod 36 that extends along the center axis A. The damper rod 36 includes a rod end 38 located inside of the fluid compartment 32, 34. A piston 40 is attached to the damper rod 36 adjacent to the rod end 38, and configured to move with the damper rod 36 along the center axis A through the damper tube 22. The piston 40 divides the fluid compartment 32, 34 into a compression chamber 32 and a rebound chamber 34. The compression chamber 32 extends between the piston 40 and the gas cup 28, and the rebound chamber 34 extends between the second end 26 and the piston 40.
A first closure 42 seals the gas compartment 30 at the first end 24 of the damper tube 22. A damper mount 44 is attached to the first closure 42 and configured to attach the damper assembly 20 to a body of a vehicle (not shown). The damper assembly 20 of the present disclosure may be used in other configurations and/or orientations. For example, the damper mount 44 may connect the damper tube 22 of the damper assembly 20 to a chassis component of the vehicle 10.
The damper assembly 20 also includes a second closure 46 disposed adjacent to the second end 26 of the damper tube 22 to enclose the rebound chamber 34. The second closure 46 defines a bore 48 for the damper rod 36 to pass through. The second closure 46 may provide a fluid-tight seal with the damper rod 36 to prevent fluid from leaking out of the rebound chamber 34.
As also shown in
The piston 40 also includes a compression valve assembly 70, 72, 73, 74 configured to regulate fluid flow from the compression chamber 32 to the rebound chamber 34 during a compression stroke, with the damper rod 36 pushing the piston 40 toward the first end 24 of the damper tube 22. The compression valve assembly 70, 72, 73, 74 includes a compression disc retainer 70 having a ring shape disposed about the first rod extension 53 and contacting the first rod shoulder 52. The compression valve assembly 70, 72, 73, 74 also includes a first spacer ring 72 having a ring shape disposed about the first rod extension 53 adjacent to the compression disc retainer 70 and opposite from the first rod shoulder 52. The compression valve assembly 70, 72, 73, 74 also includes a compression disc stack 73, 74 covering an end of the compression passage 64 opposite from the compression chamber 32. The compression disc stack 73, 74 includes a plurality of first compression discs 73 and a plurality of second compression discs 74 that are wider than the first compression discs 73. However, the compression disc stack 73, 74 may include a different number of the first compression discs 73 and/or the second compression discs 74. Alternatively, the compression disc stack 73, 74 may include only discs having a uniform size. For example, the compression disc stack 73, 74 may include only the first compression discs 73 and/or only the second compression discs 74. The first spacer ring 72 has a smaller diameter than the compression disc stack 73, 74 and supports an inner portion of the compression disc stack 73, 74, leaving an outer portion of the compression disc stack 73, 74 unsupported and able to be deflected away from the compression passage 64 in response to a pressure differential thereacross, and to thereby regulate fluid flow through the compression passage 64 and into the rebound chamber 34.
The piston 40 also includes a rebound valve assembly 76, 78, 80 configured to regulate fluid flow from the rebound chamber 34 to the compression chamber 32 during a rebound stroke, with the damper rod 36 pulling the piston 40 toward the second end 26. The rebound valve assembly 76, 78, 80 includes a second spacer ring 76 having a ring shape disposed about the first rod extension 53 adjacent to the compression disc stack 73, 74 and opposite from the first spacer ring 72. The rebound valve assembly 76, 78, 80 also includes a rebound disc stack 78 including a plurality of discs covering an end of the second rebound passage 68 opposite from the frequency-dependent valve 90. The second spacer ring 76 has a smaller diameter than the rebound disc stack 78 and supports an inner portion of the rebound disc stack 78, leaving an outer portion of the rebound disc stack 78 unsupported and able to be deflected away from the second rebound passage 68 in response to a pressure differential thereacross, and to thereby regulate fluid flow through the second rebound passage 68 and into the compression chamber 32.
The rebound valve assembly 76, 78, 80 also includes a rebound bypass disc 80 disposed between the second rebound passage 68 and the rebound disc stack 78. The rebound bypass disc 80 has a disc shape with a plurality of notches in a peripheral edge thereof to provide a limited fluid communication between the second rebound passage 68 and the compression passage 64, which may equalize pressure therebetween and when the rebound disc stack 78 is not deflected away from the second rebound passage 68.
Still referring to
The FD valve 90 also includes an FD control stack 92, 94, 98, 100 disposed around the second rod extension 55 between the intermediate chamber 67 and the FD slider 102. The FD control stack 92, 94, 98, 100 is best shown in the exploded diagram on
A coil spring 106 contacts the FD slider 102 and biases the FD slider 102 toward the FD control stack 92, 94, 98, 100.
An FD working disc stack 120 including one or more FD working discs overlies the spring retainer 112 and contacts a rim 119 of the FD housing 110. The FD working disc stack 120 is configured to deflect together with the FD housing 110 for regulating fluid flow between the rebound chamber 34 and the compression chamber 32 by applying additional force to the FD housing 110. The FD working disc stack 120 includes an FD bypass disc 114 having a number of notches in a peripheral edge thereof to allow fluid from within the FD displacement chamber 118 to flow into the compression chamber 32. The FD valve 90 also includes a fourth spacer ring 122 having a ring shape disposed about the third rod extension 57 and adjacent to the FD working disc stack 120 and opposite from the spring retainer 112. The fourth spacer ring 122 has a smaller diameter than the FD working disc stack 120 and supports an inner portion of the FD working disc stack 120, leaving an outer portion of the FD working disc stack 120 unsupported and able to be deflected together with the FD housing 110 in response to a pressure differential thereacross, and to thereby regulate fluid flow from the FD displacement chamber 118 and into the compression chamber 32.
The FD valve 90 also includes an FD disc retainer 124 having a disc shape disposed around the third rod extension 57 and overlying the fourth spacer ring 122, opposite from the FD working disc stack 120. A fastener 126 is disposed around the third rod extension 57 and contacting the FD disc retainer 124 for securing the FD valve 90 to the damper rod 36. The fastener 126 may include a nut that threadedly engages the third rod extension 57, although other types of fasteners may be used.
As shown on
As also shown in
As shown in
As best shown in
During the rebound stroke, fluid flows from the rebound chamber 34 via the first rebound passage 66 and the intermediate chamber 67, through the control orifice 96 in the FD control disc 94 and into the FD pressure chamber 116, causing the FD slider 102 to move in an axial direction toward the rod end 38. In other words, the control orifice 96 in the FD control disc 94 provides fluid communication between the intermediate chamber 67 and the FD pressure chamber 116, as indicated by the small flow arrow on
When a sufficient pressure occurs in the FD pressure chamber 116, the FD slider 102 moves axially towards the rod end 38 (i.e. away from the FD control stack 92, 94, 98, 100, thus increasing volume of the FD pressure chamber 116. The FD bypass disc 114 located adjacent to the FD working disc stack 120 enables oil to freely flow into and out of the FD displacement chamber 118, where the coil spring 106 is located, and thus enables free movement of the FD slider 102.
Operation of the FD valve 90 is tuned by flow area of the control orifice 96 in the FD control disc 94, spring rate and preload of the coil spring 106 as well as quantity and thickness of the discs of the FD working disc stack 120. The FD working disc stack 120 is responsible for generating primary damping force of FD valve 90, while FD control stack 92, 94, 98, 100 is responsible for FD valve enhancement at low frequencies. The FD working disc stack 120 also holds the FD housing 110 housing in place and biases the FD housing 110 in an axial direction towards the slotted disc 92 when the FD valve 90 closes.
The FD slider 102 may engage the catch surface 158 to define a maximum axial travel limit of the FD slider 102, which may limit a maximum pressure level in the FD pressure chamber 116. When the FD slider 102 contacts the catch surface 158, the FD slider 102 may push the FD housing 110 away from the slotted disc 92, providing enhanced flow through the FD valve 90, as illustrated in
In some embodiments, the FD valve 90 can operate as an open system where the input and output (i.e. passages providing fluid flow into and out of the FD pressure chamber 116) are isolated. For example, and as shown in
Obviously, many modifications and variations of the present invention 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. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202310181321.5 | Feb 2023 | CN | national |
