DAMPER WITH VALVE PRE-CALL LIMITER

Abstract

Damping system for a vehicle (10), comprising: a pressure tube (30) containing a hydraulic fluid; a piston rod (34) extending inside the pressure tube (30) along a longitudinal axis (35); a piston assembly (32) which is slidably fitted into the pressure tube (30) for movement along the longitudinal axis (35), wherein the piston assembly (32) is coupled to the piston rod (34) and separates the pressure tube (30) into a first working chamber (44) and a second working chamber (46), wherein the piston assembly (32) comprises a piston body (60) and a valve assembly (62, 64) which controls the fluid flow between the first working chamber and the second working chamber; a frequency-dependent damper assembly comprising a damper housing (100) coupled to the piston rod (34), a piston sleeve (102) comprising a substantially tubular element extending around an outer surface (113) of the damper housing (100) and movable longitudinally relative to the damper housing (100) along the longitudinal axis (35) between a rest position and an engagement position, and a piston chamber (190) arranged between the damper housing (100) and the piston sleeve (102), which is fluidically connected to at least one of the first working chamber and the second working chamber; wherein a pressure increase within the piston chamber (190) generates an adaptive force on the piston sleeve (102), which moves the piston sleeve (102) longitudinally in the direction of the piston assembly (32) into the engagement position, wherein the piston sleeve (102) contacts the valve assembly (62, 64) in the engagement position to transmit the adaptive force to the valve assembly (62, 64) and to increase the resistance of the valve assembly (62, 64) to opening; and a piston travel limiter (208) which is positioned longitudinally between the damper housing (100) and the valve assembly (62, 64) and which touches the piston sleeve (102) when the piston sleeve (102) is in the engagement position in order to limit the longitudinal movement of the piston sleeve (102) in the direction of the piston body (60) and to limit the adaptive force exerted by the piston sleeve (102) on the valve assembly (62, 64).

Description

AREA

[0001] This disclosure relates to shock absorbers / dampers for motor vehicles. More specifically, this disclosure relates to shock absorbers / dampers that provide a different damping quantity based on the frequency and velocity of an input to the shock absorber / damper. STATE OF THE ART

[0002] The information in this section merely provides background information relating to the present disclosure and does not necessarily represent the state of the art.

[0003] Shock absorbers are typically used in conjunction with vehicle suspension systems or other suspension systems to dampen unwanted vibrations that occur during the movement of the suspension system. To dampen these unwanted vibrations, vehicle shock absorbers are generally connected between the sprung mass (body) and the unsprung mass (suspension / drivetrain) of the vehicle.

[0004] The most common types of shock absorbers for motor vehicles are monotube and twin-tube shock absorbers. In monotube shock absorbers, a piston is located in a fluid chamber defined by a pressure tube and connected to the vehicle's sprung mass via a piston rod. The pressure tube is connected to the vehicle's unsprung mass. The piston divides the pressure tube's fluid chamber into an upper working chamber and a lower working chamber. The piston incorporates a compression valve that limits the flow of hydraulic fluid from the lower working chamber to the upper working chamber during a compression stroke. The piston also incorporates a rebound valve that limits the flow of hydraulic fluid from the upper working chamber to the lower working chamber during a rebound stroke.Since the compression and rebound valves are able to limit the flow of hydraulic fluid, the shock absorber can generate a damping force that counteracts oscillations / vibrations that would otherwise be transferred from the unsprung mass to the sprung mass.

[0005] In a twin-tube shock absorber, a fluid reservoir is defined between the pressure tube and a reservoir tube arranged around the pressure tube. A base valve assembly is located between the lower working chamber and the fluid reservoir to control the flow of damping fluid between the lower working chamber and the fluid reservoir. The piston's compression stage valve is moved to the base valve assembly and replaced within the piston by a compression stage valve assembly. In addition to the compression stage valve, the base valve assembly includes a rebound stage check valve assembly. The compression stage valve of the base valve assembly generates the damping force during a compression stroke, and the piston's rebound stage valve generates the damping force during a rebound stroke.Both the compression stage valve arrangement and the rebound stage check valve arrangement allow fluid flow in one direction but prevent fluid flow in the opposite direction, and these check valves may be designed to also generate a damping force.

[0006] Together, the compression and rebound valves and / or check valve assemblies for the shock absorber function to control the fluid flow between the upper and lower working chambers of the shock absorber. By controlling the fluid flow between the two working chambers, a pressure drop is created between them, which contributes to the damping forces of the shock absorber. The compression valve, rebound valve, and check valve assemblies can be used to adjust the damping forces to control ride and handling, as well as noise, vibration, and harshness.

[0007] Typical passive shock absorbers provide the same damping force regardless of the input frequency. For a given input velocity, the damping force produced by a conventional passive shock absorber remains constant regardless of the input frequency. The primary driving frequency of a passenger car is typically in the range of 1 to 2 Hertz. When a vehicle travels over a road surface with a lower frequency input, higher damping is preferred to control the road inputs. A higher level of damping is also preferred during handling events (where directional stability is critical). For example, the vehicle may be subject to body roll during handling events. The body roll frequency in a typical passenger car is usually between 2 and 4 Hertz, depending on the roll stiffness and the height of the vehicle's center of gravity.While there are active and semi-active damping systems that change the damping of the shock absorber in real time to respond to different vehicle suspension inputs, there is a need for a passive shock absorber that provides frequency-dependent damping without complicated and expansive active or semi-active damping control systems.

[0008] DE 10 2014 210 704 A1 discloses a damping valve device for a vibration damper, comprising a damping piston with a check valve and a control arrangement with a control pot and a control piston axially movable therein, wherein the control pot is formed from a sheet metal and the control pot has at least one stop which projects into the control chamber, at least indirectly axially supports the control piston and defines a soft damping force characteristic, wherein the stop is produced by a plastic deformation of the control pot.

[0009] DE 10 2014 210 705 A1 discloses a damping valve device for a vibration damper, comprising a damping piston with a check valve and a control arrangement with a control piston. The invention is characterized in that a spring element arranged between the control piston and the check valve, which exerts a defined spring force on the valve disc axially in the direction of the flow channel and on the control piston in the direction of the pot base, is characterized in that a surface of the control piston facing the control chamber is larger than a surface of the valve disc bounded by the flow channel, and that a minimum cross-sectional area Az of the inlet connection opening into the control chamber and a minimum cross-sectional area Aa of the outlet connection leading out of the control chamber are dimensioned such that their ratio to each other is between 0.2 and 5 according to the condition.

[0010] DE 10 2016 217 112 A1 discloses a frequency-dependent damping valve arrangement of a vibration damper, for a motor vehicle, proposed, comprising: - a damping piston arranged within a cylinder at least partially filled with a damping fluid with a check valve, a control arrangement attached to the support, coaxial to the damping piston, comprising: - a control pot, as well as a control piston arranged in the control pot and axially displaceable on a support, - at least one first end stop for limiting the axial movement of the control piston within the control pot, wherein the end stop comprises a support disc and an adjusting disc, the adjusting disc being irreversibly plastically deformable and having a lower yield strength than the support disc and / or the carrier, and wherein the axial end position of the control piston is adjustable by plastic deformation of the adjusting disc. The damping valve arrangement according to the invention is characterized in that at least one of the components, the support disc and / or the carrier, defines a free space for receiving the material of the adjusting disc displaced by the plastic deformation. SUMMARY

[0011] This section provides a general overview of the disclosure and is not a comprehensive disclosure of its scope of protection or all of its features.

[0012] According to one aspect of the present disclosure, a damping system for a vehicle is provided. The damping system includes a pressure tube and a piston assembly that is slidably fitted into the pressure tube. A piston rod extends within the pressure tube along a longitudinal axis, and the piston assembly is coupled to the piston rod. The pressure tube contains a hydraulic fluid, and the piston assembly divides the pressure tube into a first working chamber and a second working chamber. The piston assembly includes a piston body and a valve assembly. The valve assembly serves to control the hydraulic fluid between the first working chamber and the second working chamber.

[0013] The damping system also includes a frequency-dependent damper assembly. This assembly comprises a damper housing and a piston sleeve. The damper housing is coupled to the piston rod. The piston sleeve is longitudinally movable relative to the damper housing along its longitudinal axis between a rest position and an engagement position. A piston chamber is provided between the damper housing and the piston sleeve. This piston chamber is fluidically connected to at least one of the first and second working chambers. During operation, a pressure increase within the piston chamber generates an adaptive force on the piston sleeve, which moves the piston sleeve longitudinally toward the piston assembly into the engagement position. In the engagement position, the piston sleeve contacts the valve assembly and transmits the adaptive force to it.This in turn increases the opening resistance of the valve assembly, thereby increasing the damping provided by the valve assembly.

[0014] The damper system further includes a piston travel limiter positioned longitudinally between the damper body and the valve assembly. The piston sleeve contacts the piston travel limiter when it is in the engaged position. Accordingly, the piston travel limiter restricts the longitudinal movement of the piston sleeve and prevents it from moving further toward the piston body when in the engaged position. The piston travel limiter thus limits the adaptive force exerted by the piston sleeve on the valve assembly. Advantageously, the piston travel limiter prevents the piston sleeve from exerting excessive force on the valve assembly. Applying excessive force to the valve assembly is detrimental because it can cause a blockage condition in which the valve assembly does not open when it should.Excessive force can also cause permanent deformation of the valve assembly, impairing its operation. The piston travel limiter eliminates the possibility of the valve assembly seizing and improves the overall durability of the frequency-dependent damper assembly.

[0015] Further applications and advantages will become apparent from the description provided herein. It should be understood that the description and specific examples serve only for illustration and are not intended to limit the scope of protection afforded by this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described here serve only to illustrate selected embodiments and not all possible implementations, and are not intended to limit the scope of protection of the present disclosure. Fig. Figure 1 is an illustration of an exemplary vehicle equipped with a shock absorber in accordance with the teachings of the present disclosure; Fig. Figure 2 is a fragmentary side view of a shock absorber constructed according to the teachings of the present disclosure; Fig. Figure 3 is a fragmentary cross-sectional view of a shock absorber constructed according to the teachings of the present disclosure; Fig. Figure 4 is a perspective exploded view showing a piston assembly, a stack of rebound damping discs, a floating support disc, a disc spring, a piston travel limiter, and a piston sleeve of the in Fig. 3 illustrated shock absorber; Fig. Figure 5 is a fragmentary cross-sectional view of the in Fig. 3 illustrated shock absorber, which shows the piston sleeve in a rest position; Fig. 6A is a fragmentary cross-sectional view of the in Fig. 3 illustrated shock absorber, showing the piston sleeve in an engagement position; Fig. Figure 6B is a partial side view of an exemplary piston sleeve and an exemplary travel limiter of the shock absorber, taken from line 6-6 in Fig. 6A; Fig. Figure 6C is a partial side view of another exemplary piston sleeve and travel limiter of the shock absorber; Fig. Figure 7 is a fragmentary cross-sectional view showing a frequency-dependent damper assembly of the shock absorber; Fig. Figure 8A is a perspective exploded view of an exemplary check valve of the frequency-dependent damper assembly; Fig. Figure 8B is a perspective exploded view of another exemplary check valve of the frequency-dependent damper assembly; Fig. Figure 9 is a perspective exploded view of a floating valve arrangement of the frequency-dependent damper assembly; Fig. 10A is a fragmentary cross-sectional view of the in Fig. 3 illustrated shock absorber, which represents a floating piston of the frequency-dependent damper assembly in a seated position during a rebound stroke; Fig. 10B is a fragmentary cross-sectional view of the in Fig. 3 illustrated shock absorber, which shows the floating piston of the frequency-dependent damper assembly in a raised position during a rebound stroke; Fig. Figure 11 is a fragmentary cross-sectional view of the in Fig. 3 illustrated shock absorber, which represents the floating piston of the frequency-dependent damper assembly during a compression stroke; Fig. 12 is a fragmentary cross-sectional view of another shock absorber constructed according to the teachings of the present disclosure, with a floating disc added; Fig. Figure 13 is a fragmentary cross-sectional view of the in Fig. 12 illustrated shock absorbers, where the floating disc is thin; Fig. Figure 14 is a fragmentary cross-sectional view of the in Fig. 12 illustrated shock absorbers, where the floating disc is thick; Fig. Figure 15 is a fragmentary cross-sectional view of the in Fig. 12 illustrated shock absorbers, wherein the floating disc has a small diameter; and Fig. Figure 16 is a force-velocity diagram comparing several damping curves of shock absorbers constructed according to the teachings of the present disclosure.

[0017] Corresponding reference symbols designate corresponding parts across the different views of the drawings. DETAILED DESCRIPTION

[0018] The following description is merely exemplary and is not intended to limit the present disclosure, its filing or uses in any way.

[0019] Exemplary embodiments are provided to ensure that this disclosure is thorough and fully conveys the scope of protection to the person skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be obvious to the person skilled in the art that specific details need not be used, that exemplary embodiments can be embodied in many different forms, and that none of these should be interpreted as limiting the scope of protection of the disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0020] The terminology used herein serves only to describe certain exemplary embodiments and is not intended to be restrictive. As used herein, the singular forms "a" and "the" may also include the plural forms unless the context clearly indicates otherwise. The terms "comprises," "comprehensive," "including," and "indicating" are inclusive and therefore specify the presence of specified features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.The procedural steps, processes, and operations described herein are not to be interpreted as requiring their execution in the specific order discussed or presented, unless this order is specifically indicated. It is also understood that additional or alternative steps may be used.

[0021] When an element or layer is described as "on," "interacting with," "connected with," or "coupled with" another element or layer, it may be directly on, interacting with, connected to, or coupled with the other element or layer, or there may be intervening elements or layers. Conversely, when an element is described as "directly on," "directly interacting with," "directly connected with," or "directly coupled with" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted similarly (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes all combinations of one or more of the related listed elements.

[0022] Although the terms first, second, third, etc., may be used herein to describe different elements, components, areas, layers, and / or sections, these elements, components, areas, layers, and / or sections should not be restricted by these terms. These terms may only be used to distinguish one element, component, area, layer, or section from another. Terms such as "first," "second," and other numerical terms, when used herein, do not imply any sequence or order unless clearly indicated by the context.Thus, a first element, a first component, a first area, a first layer or a first section that will be discussed below could be referred to as a second element, a second component, a second area, a second layer or a second section without deviating from the teachings of the exemplary embodiments.

[0023] Spatial terms, such as "inside," "outside," "under," "below," "lower," "above," "higher," and the like, can be used here to facilitate description and to describe the relationship of one element or feature to one or more other elements or features, as illustrated in the figures. Spatial terms can also be used to encompass orientations of the device in use or operation beyond the one shown in the figures. For example, if the device in the figures is reversed, elements described as "under" or "below" other elements or features would then be oriented "above" them. Thus, the example term "under" can encompass orientations of both above and below.The device may be oriented differently (rotated by 90 degrees or in other orientations), and the spatial descriptions used herein may be interpreted accordingly.

[0024] With reference to Fig. Figure 1 illustrates a vehicle 10 including a rear suspension 12, a front suspension 14, and a body 16. The rear suspension 12 has a transverse rear axle assembly (not shown) adapted to functionally support the vehicle's rear wheels 18. The rear axle assembly is effectively coupled to the body 16 by a pair of shock absorbers 20 and a pair of coil springs 22. Similarly, the front suspension 14 includes a transverse front axle assembly (not shown) that functionally supports the vehicle's front wheels 24. The front axle assembly is effectively coupled to the body 16 by a second pair of shock absorbers 26 and a pair of coil springs 28. The shock absorbers 20 and 26 serve to dampen the relative movement of the unsprung section (i.e. front and rear wheel suspension 14, 12 respectively) and the sprung section (i.e.the body 16) of the vehicle 10. Although the vehicle 10 has been presented as a passenger car with front and rear axle assemblies, the shock absorbers 20 and 26 can be used with other types of vehicles or machines, or in other types of applications, such as vehicles that include independent front and / or independent rear suspension systems. Furthermore, the term "shock absorber" as used herein is intended to refer to shock absorbers and shock absorber systems in general, and thus includes MacPherson struts. It is also understood that the scope of protection of this disclosure is intended to include shock absorber systems for independent shock absorbers 20 and coil shock absorbers 26.

[0025] With further reference to Fig. Figure 2 shows the shock absorber 20 in more detail. Although Fig. Figure 2 shows only the shock absorber 20; it is understood that the shock absorber 26 also includes the piston arrangement described below for the shock absorber 20. The shock absorber 20 differs from the shock absorber 26 only in how it is adapted to be connected to the sprung and unsprung parts of the vehicle 10 and to the installation location of the coil spring 28 relative to the shock absorber 26.

[0026] The shock absorber 20 comprises a pressure tube 30, a piston assembly 32, and a piston rod 34. The pressure tube 30 and the piston rod 34 extend coaxially along the longitudinal axis 35. The pressure tube 30 defines an inner cavity 42. The piston assembly 32 is slidably arranged in the inner cavity 42 of the pressure tube 30 and divides the inner cavity 42 into a first working chamber 44 and a second working chamber 46. A seal 48 is arranged between the piston assembly 32 and the pressure tube 30, which allows sliding movement of the piston assembly 32 relative to the pressure tube 30 without generating excessive frictional forces and seals the first working chamber 44 against the second working chamber 46.

[0027] The piston rod 34 is attached to the piston assembly 32 and extends through the first working chamber 44 and through an upper end cap 50, which closes a first end 51 of the pressure tube 30. A fastening end 53 of the piston rod 34 opposite the piston assembly 32 is connected to the body 16 of the vehicle 10 (i.e., the sprung section of the vehicle 10). The pressure tube 30 is filled with hydraulic fluid and includes a connecting piece 54 at a second end 55 of the pressure tube 30, which is connected to the unsprung section of the suspension 12 and 14. The first working chamber 44 is thus positioned between the first end 51 of the pressure tube 30 and the piston assembly 32, and the second working chamber 46 is positioned between the second end 55 of the pressure tube 30 and the piston assembly 32. Suspension movements of the vehicle 10 cause extension / tension or compression movements of the piston assembly 32 in relation to the pressure tube 30.The valve in the piston assembly 32 controls the movement of the hydraulic fluid between the first working chamber 44 and the second working chamber 46 during the movement of the piston assembly 32 in the pressure tube 30. It is understood that the shock absorber 20 can be installed in a reverse orientation, with the mounting end 53 of the piston rod 34 connected to the unsprung section of the suspension 12 and 14 and the connecting piece 54 connected to the body 16 (i.e., the sprung section of the vehicle 10).

[0028] With further reference to the Fig. 3 and Fig. Figure 4 comprises the piston assembly 32, a piston body 60 attached to the piston rod 34, a compression stage valve assembly 62, a rebound stage valve assembly 64, and a frequency-dependent damper assembly 66. The piston rod 34 includes a reduced-diameter region 68 located at the end of the piston rod 34, which is arranged within the pressure tube 30, such that the reduced-diameter region 68 forms a shoulder 70 abutting the piston assembly 32. The piston body 60 is located on the reduced-diameter region 68, with the compression stage valve assembly 62 arranged longitudinally between the piston body 60 and the shoulder 70, and with the rebound stage valve assembly 64 arranged longitudinally between the piston body 60 and a threaded end 72 of the piston rod 34. The piston body 60 defines a plurality of compression stage flow channels 74 and a plurality of rebound stage flow channels 76.The pressure stage valve arrangement 62 serves to control the fluid flow of the hydraulic fluid through the plurality of pressure stage flow channels 74 in the piston body 60, and the rebound stage valve arrangement 64 serves to control the fluid flow of the hydraulic fluid through the plurality of rebound stage flow channels 76 in the piston body 60. Therefore, both the pressure stage valve arrangement 62 and the rebound stage valve arrangement 64 control the fluid flow between the first and the second working chamber 44, 46 and thus act together to form a first valve arrangement.

[0029] The pressure stage valve assembly 62 comprises a plurality of pressure stage valve plates 78 and a valve stop 80. The pressure stage valve plates 78 are arranged adjacent to the piston body 60 to cover the plurality of pressure stage flow channels 74. During a compression stroke of the shock absorber 20, fluid pressure builds up in the second working chamber 46 until the fluid pressure applied to the pressure stage valve plates 78 via the plurality of pressure stage flow channels 74 overcomes the load required to deflect the plurality of pressure stage valve plates 78. The pressure stage valve plates 78 deflect elastically to open the pressure stage flow channels 74 and allow the flow of hydraulic fluid from the second working chamber 46 to the first working chamber 44, as indicated by the arrows 82 in the figure. Fig. Figure 3 shows the valve stop 80 being arranged between the pressure stage valve plates 78 and the shoulder 70 to limit the deflection of the pressure stage valve plates 78.

[0030] The rebound valve assembly 64 comprises a plurality of rebound valve plates 86. The rebound valve plates 86 are arranged adjacent to the piston body 60 to cover the plurality of rebound flow channels 76. The frequency-dependent damper assembly 66 is screwed onto the threaded end 72 of the piston rod 34. A sleeve 88 is positioned longitudinally between the frequency-dependent damper assembly 66 and the plurality of rebound valve plates 86. The sleeve 88 extends annularly around the reduced-diameter region 68 of the piston rod 34. Therefore, when the frequency-dependent damper assembly 66 is screwed onto the threaded end 72 of the piston rod 34, the plurality of rebound valve plates 86 are clamped between the sleeve 88 and the piston body 60.During an extension or retraction stroke of the shock absorber 20, fluid pressure builds up in the first working chamber 44 until the fluid pressure applied to the rebound valve plates 86 overcomes the load required to deflect the rebound valve plates 86 through the rebound flow channels 76. The multiple rebound valve plates 86 deflect elastically, thereby opening the rebound flow channels 76 to allow the hydraulic fluid to flow from the first working chamber 44 to the second working chamber 46, as indicated by arrows 92 in Figure 1. Fig. 3 shown.

[0031] The entire frequency-dependent damper assembly 66 shifts longitudinally along its longitudinal axis during the extension / retraction and compression movements of the piston rod 34, as the frequency-dependent damper assembly 66 is fixed to the piston rod 34. Although the frequency-dependent damper assembly 66 is rigidly connected to the piston assembly 32, it is radially spaced inside the pressure tube 30 and therefore does not seal against the pressure tube 30.

[0032] The frequency-dependent damper assembly 66 comprises a damper housing 100, a piston sleeve 102, and a check valve 104. The damper housing 100 includes a first end 105, which is screwed onto the threaded end 72 of the piston rod 34, a second end 106 opposite the first end 105, and a damper cavity 107 extending through the damper housing 100 from the first end 105 to the second end 106. The damper cavity 107 is thus defined by an inner surface 108 of the damper housing 100. The check valve 104 is located within the damper cavity 107 adjacent to the first end 105 and is held in place by a check valve carrier 109, which is screwed into the inner surface 108 of the damper housing 100. Alternatively, the check valve carrier 109 can be held in the damper housing 100 by a crimp or a support.The piston sleeve 102 encloses a first end 111 which is positioned adjacent to the first end 105 of the damper housing 100.

[0033] A flow channel 110, extending through the piston rod 34, is in fluid communication with the first working chamber 44 and a stage chamber 112, which are located in the damper cavity 107 adjacent to the first end 105 of the damper housing 100. The stage chamber 112 is partially defined by the damper housing 100 and the check valve 104. The piston sleeve 102 is an essentially tubular element that extends around an outer surface 113 of the damper housing 100 and includes a reduced-diameter section 170 and an increased-diameter section 172.The outer surface 113 of the valve housing 100 encloses a similarly stepped structure with a reduced-diameter section 176, an enlarged-diameter section 178, and a medium-diameter section 180, positioned longitudinally between the reduced-diameter section 176 and the enlarged-diameter section 178. A first seal 182 is positioned in a groove 184 of the valve housing 100. A second seal 186 is positioned in a second groove 188 of the valve housing 100. Due to the longitudinal position of the first seal 182, the second seal 186, and the intermediate section 180, a piston chamber 190 is provided between the outer surface 113 of the damper housing 100 and the piston sleeve 102. The recess 192 extends through the damper housing 100 between the damper cavity 107 and the piston chamber 190.

[0034] An end plate 191 is positioned in the damper cavity 107 and secured at the second end 106 of the damper housing 100. A floating piston 193 is housed within the damper cavity 107 and is positioned longitudinally relative to the valve housing 100 along the longitudinal axis 35 between a seating position ( Fig. 10A) and a detached position ( Fig. 10B) is displaceable. Within the damper cavity 107, a first and a second storage chamber 194, 195 are arranged, separated by the floating piston 193. The first storage chamber 194 is arranged longitudinally between the floating piston 193 and the check valve 104, and the second storage chamber 195 is arranged longitudinally between the floating piston 193 and the end plate 191. The first storage chamber 194 is in fluid communication with the second storage chamber 195 via a vent channel 196 extending through the floating piston 193. The size of the vent channel 196 can be modified to change the damping characteristics of the frequency-dependent damper assembly 66.For example, and without limitation, the vent channel 196 in the floating piston 193 can have a cross-sectional area that limits the volumetric flow rate of the fluid flowing between the first and second storage chambers 194, 195 to provide reduced damping when the movement of the piston rod 34 has a frequency above 6 hertz (Hz) and a velocity below 0.02 meters per second (m / s). According to this example, the cross-sectional area of ​​the vent channel 196 can be in the range of 0.1 to 3.0 square millimeters (mm²). 2 ) lay.

[0035] The floating piston 193 carries a seal 197 that prevents fluid from entering between the floating piston 193 and the inner surface 108 of the damper housing 100. The amount of axial travel undertaken by the floating piston 193 can be varied based on the placement of a stop 198 formed on the damper housing 100 and the relative position of the end plate 191. By varying the longitudinal position of these components, the maximum total volume of the first and second storage chambers 194, 195 can be varied to produce low-frequency deceleration.

[0036] The recess 192 brings the piston chamber 190 into fluid communication with the first storage chamber 194. When the piston chamber 190 is pressurized by the fluid flowing from the first storage chamber 194 through the recess 192 into the piston chamber 190, the piston sleeve 102 is moved longitudinally in the direction of the rebound valve arrangement 64 from a rest position ( Fig. 5) into an intervention position ( Fig. 6A) crowded. In the intervention position ( Fig. 6A) The piston sleeve 102 exerts an adaptive force on the rebound valve assembly 64. One magnitude of the adaptive force exerted by the piston sleeve 102 on the rebound valve assembly 64 is based on the pressure within the piston chamber 190 and the effective surface area on an annular web 199 on the piston sleeve 102, which extends between the reduced-diameter section 170 and the increased-diameter section 172 of the piston sleeve 102. A surface area of ​​the annular web 199, upon which the pressurized fluid acts, generates the adaptive force exerted by the piston sleeve 102 on the rebound valve assembly 64. It should be noted that the effective area of ​​the annular web 199 can be varied by changing the diameter difference between the reduced-diameter section 170 and the increased-diameter section 172 of the piston sleeve 102.By varying the surface of the bridge 199, the adaptive force exerted by the piston sleeve 102 on the rebound valve assembly 64 changes.

[0037] In the illustrated embodiment, the rebound valve assembly 64 includes a floating support disc 200 and an elastic element 201. The floating support disc 200 extends annularly around the sleeve 88 and can displace longitudinally relative to it. The floating support disc 200 is therefore movable longitudinally relative to the piston body 60. As is best done in Fig. As shown in Figure 4, the floating support disc 200 encloses an engagement surface 202, a cavity 203 of the floating support disc opposite the engagement surface 202, and an outer edge 204. The engagement surface 202 of the floating support disc 200 faces the plurality of rebound valve plates 86. The elastic element 201 is coupled to the piston rod 34 between the floating support disc 200 and the frequency-dependent damper assembly 66. The elastic element 201 exerts a preload force on the floating support disc 200, which biases the floating support disc 200 in the direction of the rebound valve arrangement 64.

[0038] Although other configurations are possible, in the illustrated embodiment the elastic element 201 is a disc spring that contacts the outer edge 204 of the floating support disc 200. When the piston sleeve 102 is in the engaged position ( Fig. 6A), the piston sleeve 102 contacts the elastic element 201, thereby transmitting the adaptive force to the elastic element 201. The adaptive force transmitted by the piston sleeve 102 to the elastic element 201 serves to increase the preload force exerted by the elastic element 201 on the floating support disc 200. The cavity 203 of the floating support disc faces the elastic element 201 and is configured such that the elastic element 201 is at least partially contained within the cavity 203 of the floating support disc when the piston sleeve 102 contacts the elastic element 201 in the engagement position. In the illustrated example, the floating support disc 200 has an annular step 205 in the cavity 203 of the floating support disc, which is dimensioned to accommodate the bending of the elastic element 201.It should be noted that the location and depth of the cavity 203 of the floating support disc and the annular step 205 are design parameters that can be modified to vary the magnitude of the preload force and the adaptive force exerted on the plurality of rebound valve plates 86. It is also understood that alternative embodiments are possible in which the floating support disc 200 and / or the elastic element 201 are omitted. Where the elastic element 201 is omitted, the piston sleeve 102 contacts the floating support disc 200 and exerts the adaptive force directly on it. If the floating support disc 200 is omitted, the piston sleeve 102 contacts the rebound valve plates 86 of the rebound valve assembly 64 and exerts the adaptive force directly on them.

[0039] In the illustrated example, the floating support disc 200 supports the multiple rebound valve plates 86 on an outer circumference. This ensures that a given amount of adaptive force generates a maximum amount of resistance for the rebound valve assembly 64, opposing its opening. The design of the piston sleeve 102 incorporates a smaller effective area for the annular web 199, which in turn allows for a smaller outer diameter for the enlarged-diameter section 172, thus affecting the packing. Optimizing the components also makes it possible to apply a single design to multiple bores, thereby reducing manufacturing effort.

[0040] It should be noted that the radial position of the engagement surface 202 can be varied to exert a force on different sections of the plurality of rebound valve plates 86, thereby producing a different modification of the performance of the rebound valve assembly 64. To tailor the suspension characteristics to a specific vehicle application, it may be desirable to modify the system response and operation of the rebound valve assembly 64 based on the vehicle type and configuration. By using a number of different floating support discs 200 with an engagement surface 202 positioned in different radial positions, a common damper housing 100 and a common piston sleeve 102 can be used within the entire shock absorber family 20, 26.

[0041] Another feature of the floating support disc 200 concerns its degree of freedom of longitudinal translation, which enables the blow-off of the rebound valve arrangement 64. Fig. Figure 5 shows the piston sleeve 102 in the rest position, in which no force is exerted on the rebound valve assembly 64. As in Fig. As shown in Figure 6A, the longitudinal movement of the piston sleeve 102 towards the piston body 60 is limited by a piston travel limiter 208, which is positioned longitudinally between the damper housing 100 and the rebound valve assembly 64. Although other configurations are possible, in the illustrated embodiment a spacer 209 is positioned longitudinally between the piston travel limiter 208 and the elastic element 201. The spacer 209 extends annularly around the reduced-diameter region 68 of the piston rod 38. Accordingly, the elastic element 201 is clamped between the sleeve 88 and the spacer 209, and the piston travel limiter 208 is clamped between the spacer 209 and the first end 105 of the damper housing 100 when the frequency-dependent damper assembly 66 is screwed onto the threaded end 72 of the piston rod 34.The first end 111 of the piston sleeve 102 contacts the piston travel limiter 208 in the engagement position. Both the piston travel limiter 208 and the elastic element 201 are made of elastic materials that can bend, thus providing a soft stop for the piston sleeve 102 as the piston sleeve 102 approaches the engagement position. As shown in . Fig. As shown in Figure 3, the damper housing 100 can optionally include one or more stages 210 that contact the piston sleeve 102 in the rest position to provide a hard stop as the piston sleeve 102 approaches the rest position.

[0042] The piston travel limiter 208 touches the piston sleeve 102 when the piston sleeve 102 is in the engagement position ( Fig. 6A), to limit the longitudinal movement of the piston sleeve 102 in the direction of the piston body 60. As a result, the piston sleeve 102 limits the adaptive force that the piston sleeve 102 exerts on the elastic element 201, which is ultimately transmitted via the floating support disc 200 of the rebound valve assembly 64 to the plurality of rebound valve plates 86.

[0043] How best to Fig. As can be seen in Figure 4, the piston travel limiter 208 includes one or more tabs 211 that extend radially outwards towards the pressure tube 30. The piston sleeve 102 includes one or more notches 212 that are aligned circumferentially with the tabs 211 of the piston travel limiter 208, such that the notches 212 in the piston sleeve 102 engage the tabs 211 of the piston travel limiter 208 when the piston sleeve 102 moves longitudinally relative to the piston travel limiter 208 between the rest position ( Fig. 5) and the intervention position ( Fig. 6A) moves. Each notch 212 encloses an insert surface 213 that contacts the tab 211, which is slidably received therein when the piston sleeve 102 is in the engagement position ( Fig. 6A), which prevents the piston sleeve 102 from moving further towards the piston body 60. It should be noted that this arrangement could be reversed, with notches provided in the piston travel limiter 208 and tabs provided on the piston sleeve 102. It should also be noted that other protrusions or mechanical structures besides the tab 211 and notch 212 arrangement described herein are possible.

[0044] For example, in the Fig. In the embodiment shown in Figure 6B, the notches 212 in the piston sleeve 102 extend linearly along the piston sleeve 102 in a direction parallel to the longitudinal axis 35. As a result, the notches 212 have a rectangular profile 221 in side view. This configuration limits the longitudinal movement of the piston sleeve 102 in one direction when the tab 211 of the piston stroke limiter 208 contacts the insertion surface 213 of the notch 212, thus stopping the longitudinal movement of the piston sleeve 102 towards the piston body 60. The point of contact between the tab 211 and the insertion surface 213 of the notch 212 therefore defines the position of the piston sleeve 102 in the engagement position.

[0045] Fig. Figure 6C illustrates an alternative embodiment in which the notches 212' in the piston sleeve 102' have an L-shaped profile 223. Consequently, each notch 212' extends linearly along the piston sleeve 102' in a direction parallel to the longitudinal axis 35 to define a longitudinal section 225 of the notch 212', and circumferentially along the piston sleeve 102' to define a circumferential section 227 of the notch 212'. The piston sleeve 102' has a hook section 229 that extends over the circumferential section 227 of the notch 212'. The hook section 229 of the piston sleeve 102' has an inner surface 231 that faces the circumferential section 227 of the notch 212'. When installing the piston sleeve 102', the tab 211 of the piston travel limiter 208 is first engaged in the longitudinal section 225 of the notch 212'. Then the piston sleeve 102' is rotated relative to the piston travel limiter 208 to position the tab 211 in the circumferential section 227 of the notch 212'.This configuration limits the longitudinal movement of the piston sleeve 102' in two directions. The contact between the tab 211 of the piston travel limiter 208 and the insert surface 213' of the notch 212' limits the distance by which the piston sleeve 102 may move longitudinally towards the piston body 60. The point of contact between the tab 211 and the insert surface 213' of the notch 212' thus defines the position of the piston sleeve 102' in the engaged position. The contact between the tab 211 of the piston travel limiter 208 and the inner surface 231 of the detent section 229 of the piston sleeve 102' limits the distance by which the piston sleeve 102' may move longitudinally away from the piston body 60. The point of contact between the tab 211 and the inner surface 231 of the hook section 229 thus defines the position of the piston sleeve 102' in the rest position.Since the piston travel limiter 108 is made of an elastic material and can bend, this configuration provides soft stops in both the engaged and rest positions of the piston sleeve 102'. In both embodiments, which are described in the . Fig. 6B and Fig. As shown in Figure 6C, the notches 212, 212' are open to the first end 111 of the piston sleeve 102, 102' so that they are configured to receive the tabs 211 of the piston travel limiter 208 during the assembly of the frequency-dependent damper assembly 66.

[0046] How best to Fig. As can be seen in Figure 7, the end plate 191 of the frequency-dependent damper assembly 66 includes one or more channels 214, which are in fluid communication with the second storage chamber 195 and the second working chamber 46. The frequency-dependent damper assembly 66 also includes a floating valve assembly 215 (i.e., a second valve assembly) that is supported on the floating piston 193, such that the floating valve assembly 215 moves longitudinally with the floating piston 193 relative to the damper housing 100. Although other configurations are possible, in the illustrated embodiment, the floating valve assembly 215 is mounted on an extension section 216 of the floating piston 193, which extends longitudinally from the floating piston 193 to the end plate 191. A retainer 217 secures the floating valve assembly 215 to the extension section 216 of the floating piston 193.As a non-restrictive example, the extension section 216 of the floating piston 193 can be threaded, and the holder 217 can engage the extension section 216 in threaded engagement. The end plate 191 encloses an end plate cavity 220, which, together with the floating valve assembly 215, defines the second storage chamber 195. The end plate cavity 220 is spaced radially inward from the channels 214 in the end plate 191, which are positioned radially between the end plate cavity 220 and an outer circumference of the end plate 191. The extension section 216 of the floating piston 193 and the holder 217 are at least partially contained within the end plate cavity 220 when the floating piston 193 is in the seated position. Fig. 10A).

[0047] Fig. Figure 8A illustrates the check valve 104, which includes a support disc 284, a spacer disc 286, a detent disc 288, and a support disc 290. Each of the discs 284, 286, 288, and 290 is arranged adjacent to the other and is clamped against the damper housing 100 by the check valve carrier 109. Fig. 3) The detent disk 288 encloses a movable flap 292, which is connected to an outer ring 294 via a hinge 296. The deflection of the flap 292 towards the first storage chamber 194 is limited by the support disk 290. During a pull stroke, fluid enters the center of the detent disk 288 through the recesses 295 of the support disk 284 and through a passage 298. The detent disk 288 is a spring steel disk, allowing the flap 292 to move relative to the outer ring 294 during a compression stroke. The spacer disk 286 has an enlarged recess 299 compared to a recess 301 of the support disk 290. During a compression stroke, the flap 292 is pre-tensioned into the recess 299 to allow a fluid flow from the first storage chamber 194 through the check valve 104 and into the stage chamber 112.The thickness of the spacer 286 varies the travel of the flap 292 and thus the flow cross-section through the recess 299. Accordingly, the fluid flow through the check valve 104 is throttled comparatively less during a compression stroke and comparatively more during a contraction stroke.

[0048] Fig. Figure 8B illustrates an alternative design for a check valve 104', which includes a support washer 284', a spacer washer 286', a detent washer 288', a vent washer 289', a seat washer 290', and a seal 291'. Each of the washers 284', 286', 288', 289', 290' is arranged adjacent to the other and is clamped against the damper housing 100 by the check valve carrier 109 ( Fig. 3) The seal 291' is provided with an opening 293'. The ratchet disc 288' encloses a movable flap 292', which is connected to an outer ring 294' via a hinge 296'. The circumferential slot 297' extends around the flap 292', except where the hinge 296' connects the flap 292' to the outer ring 294'. This gives the circumferential slot 297' a C-shaped form. The deflection of the flap 292' towards the step chamber 112 is limited by the support disc 284'. During a pull stroke, fluid passes through the opening 293' in the seal 291', through recesses 295' in the support disc 284', through an enlarged recess 299' in the spacer disc 286' and through the circumferential slot 297' in the detent disc 288'.The passage opening 298' in the vent disc 289' contains a circular section 302' located centrally in the vent disc 289', a circumferential section 304' aligned with the circumferential slot 297' in the detent disc 288', and a passage 305' extending radially between the circular section 302' and the circumferential section 304' of the passage opening 298'. The seat disc 290' overlaps the circumferential section 304' and the passage 305' and therefore blocks the longitudinal fluid flow through the circumferential section 304' and the passage 305' of the passage opening 298'.Thus, during a pull stroke, a fluid flow enters the circumferential section 304' from the circumferential slot 297' in the detent disc 288' and then flows radially inwards through the passage 305' in the vent disc 289' to the circular section 302' of the passage opening 298' and then out of the check valve 104' through the recess 301' in the seat disc 290'. The circumferential section 304' of the passage opening 298' can be wider than the pivot part 296' of the detent disc 288' to prevent the pivot part 296' from completely blocking the circumferential section 304' of the passage opening 298', even if the pivot part 296' overlaps part of the circumferential section 304' of the passage opening 298'. The detent disc 288' is a spring steel disc, allowing the flap 292' to move relative to the outer ring 294' during a compression stroke. The enlarged recess 299' of the spacer disc 286' is larger than the recess 301' of the seat disc 290'.During a compression stroke, the flap 292' is biased into the recess 299' to allow fluid flow from the first storage chamber 194 through the check valve 104' and into the stage chamber 112. More precisely, the fluid flow passes through the recess 301' and the through-hole 298', past the deflected flap 292' (via the circumferential slot 297' in the detent disc 288' and the enlarged recess 299' in the spacer disc 286'), through the recesses 295' in the support disc 284', and out of the check valve 104' through the opening 293' in the seal 291'. The thickness of the spacer disc 286' varies the travel of the flap 292' and thus the flow cross-section through the recess 299'. Accordingly, the fluid flow through the check valve 104' is throttled comparatively less during a compression stroke and comparatively more during a pull stroke.

[0049] How best to in the Fig. 7 and Fig. As can be seen in Figure 9, the floating valve assembly 215 includes one or more valve plates 218a, 218b, which are elastic and positioned longitudinally between the floating piston 193 and the end plate 191. The plate 218b of the floating valve assembly 215 contacts a lip 219 of the end plate 191 when the floating piston is in the seated position ( Fig. 10A), and the plate 218b is spaced longitudinally from the lip 219 of the end plate 191 when the floating piston 193 is in the raised position ( Fig. 10B). The plate 218b of the second valve assembly 215 includes one or more vent ports 303 arranged around an outer circumference of the plate 218b. The vent ports 303 are in fluid communication with the channels 214 in the end plate 191. Accordingly, the vent ports 303 allow fluid to be vented from the second storage chamber 195 and into the channels 214 when the plate 218b is in contact with the end plate 191, which is the case when the floating piston 193 is in the seated position ( Fig. 10A). Each vent port 303 has a cross-sectional area that reduces a volumetric flow rate of the fluid flowing between the second storage chamber 195 and the channels 214 in the end plate 191 when the floating piston 193 is in the seated position ( Fig. 10A), compared to the volumetric flow rate of the fluid flowing between the second storage chamber 195 and the channels 214 in the end plate 191 when the floating piston 193 is in the lifted position ( Fig. 10B). For example, and without limitation, each of the vent connections 303 in plate 218b can have a cross-sectional area of ​​0.1 to 3.0 square millimeters (mm²). 2 exhibit.

[0050] The operation of the shock absorber 20 varies based on the direction and frequency of the input forces. A low-frequency rebound mode is described below. As in Fig. As shown in Figure 3, during a tensile stroke, fluid is compressed in the first working chamber 44 and flows between the first working chamber 44 and the second working chamber 46 through the tensile flow channel 76, overcoming the load required to deflect the tensile valve plates 86 of the tensile valve assembly 64 so that fluid flows as indicated by arrow 92. As shown in Fig. As shown in Figure 10A, the fluid pressure in the first working chamber 44 also flows through the channel 110 in the piston rod 34 and into the stage chamber 112. From the stage chamber 112, fluid passes through the check valve 104 and enters the first storage chamber 194. Consequently, the pressure of the fluid in the first storage chamber 194, which is downstream of the check valve 104, is lower than the pressure of the fluid in the stage chamber 112. The pressure of the fluid in the first storage chamber 194 holds the floating piston 193 in the seated position. Since the recesses 192 in the damper housing 100 fluidically connect the first storage chamber 194 and the piston chamber 190, fluid flows from the first storage chamber 194 to the piston chamber 190 along the flow path F1, so that the pressure of the fluid in the first storage chamber 194 fills the piston chamber 190 during the low-frequency rebound stage, forcing the piston sleeve 102 into the engagement position.The adaptive force of the piston sleeve 102 is exerted on the rebound valve plates 86 and generates increased resistance against the rebound valve assembly 64, which counteracts the opening of the rebound valve assembly 64 during low-frequency rebound conditions. It should be noted that a certain time interval is required for fluid to flow from the stage chamber 112 to the first storage chamber 194 and the piston chamber 190. This time delay for providing the controlled pressure build-up in the first storage chamber 194 and the piston chamber 190 by the check valve 104 provides frequency-dependent damping.

[0051] Fig. Figure 10A illustrates a fluid flow through the frequency-dependent damper assembly 66 when the shock absorber is subjected to 20 low-frequency rebound inputs. As shown in Fig. As shown in Figure 10A, a first fluid flow path 400 is defined during the pull stroke of the piston arrangement 32 when the fluid pressure in the first storage chamber 194 is higher than the fluid pressure in the second storage chamber 195 and the floating piston 193 is in the seated position. The first fluid flow path 400 extends from the first working chamber 44 and through the channel 110 in the piston rod 38. The fluid in the first fluid flow path 400 then flows through the check valve 104 into the first collecting chamber 194. From there, the fluid in the first fluid flow path 400 flows through the vent channel 196 in the floating piston 193 and into the second storage chamber 195. The fluid in the first fluid flow path 400 then flows from the second storage chamber 195 through the vent ports 303 in the plate 218b of the floating valve assembly 215, through the channels 214 in the end plate 191, and out into the second working chamber 46.

[0052] With reference to Fig. When the damper enters rebound mode during a high-frequency input mode, fluid enters the stage chamber 112 and the first and second reservoir chambers 194 and 195 at a higher volumetric flow rate through channel 110 in piston rod 34. This higher volumetric flow rate is limited when the fluid flows through vent ports 303 in plate 218b, causing a pressure increase in the second reservoir chamber 195. This pressure increase in the second reservoir chamber 195 moves the floating piston 193 into the released position ( Fig. 10B), which allows the fluid to flow out of the first and second storage chambers 194, 195 at a higher volumetric flow rate than when the floating piston 193 is in the lifted position ( Fig. 10A). This creates a blow-off state in the frequency-dependent damper assembly 66, whereby pressure drops in the first and second storage chambers 194, 195 and in the piston chamber 190 cause the piston sleeve 102 to move into the rest position. In the rest position, the piston sleeve 102 exerts no adaptive force on the rebound valve plates 86, and therefore the rebound valve assembly 64 provides less damping during high-frequency rebound inputs.

[0053] Due to the nature of the high-frequency rebound inputs, a piston rod stroke reversal occurs before the fluid has time to build up pressure within the piston chamber 190. This time requirement prevents additional stress on the piston sleeve 102. The pressure in the piston chamber 190, which can drive the movement of the piston sleeve 102 relative to the pressure in the first storage chamber 194, determines the magnitude of the adaptive force that the piston sleeve 102 will generate. This, in turn, depends on the input frequency. At higher frequencies, there is insufficient time to fill the piston chamber 190. At lower frequencies, fluid pressure builds up in the piston chamber 190 and acts on the web 199 of the piston sleeve 102 to move the piston sleeve 102 into the engagement position and generate the adaptive force.It should be noted that during a pull stroke of either high or low frequency, the fluid flow path through the piston arrangement 32 along arrows 82 remains the same (. Fig. 3) The only change is the magnitude of the adaptive force on the rebound valve plates 86 to limit the opening of the rebound valve assembly 64.

[0054] Fig. Figure 10B illustrates a fluid flow through the frequency-dependent damper assembly 66 when the shock absorber is subjected to 20 high-frequency rebound inputs. As shown in Fig. As shown in Figure 10B, a second fluid flow path 402 is defined during a pull stroke of the piston arrangement 32 when the fluid pressure in the first storage chamber 194 is less than or equal to the fluid pressure in the second storage chamber 195 and the floating piston 193 is in the lifted position. The second fluid flow path 402 extends from the first working chamber 44 and through the channel 110 in the piston rod 34. The fluid flowing in the second fluid flow path 402 flows through the check valve 104 into the first collecting chamber 194. Fluid flowing in the second fluid flow path 402 flows through the vent channel 196 in the floating piston 193 from the first storage chamber 194 to the second storage chamber 195. Fluid flowing in the second fluid flow path 402 then flows between the plate 218b of the second valve assembly 215 and the lip 219 of the end plate 191, through the channels 214 in the end plate 191 and out into the second working chamber 46.It should be noted that the volumetric flow rate of the fluid passing through the first fluid flow path is 400 (. Fig. 10A) flows, compared to the fluid flowing through the second fluid flow path 402 ( Fig. 10B) flows, less (i.e. more restricted).

[0055] Since the shock absorber 20 reaches its limit or compresses, the pressure in the first working chamber 44 is lower than in the second working chamber 46. As in Fig. As shown in Figure 3, during a compression stroke, fluid in the second working chamber 46 is compressed and flows between the second working chamber 46 and the first working chamber 44 through the pressure stage flow channel 74, overcoming the load required to deflect the pressure stage valve plates 78 of the pressure stage valve assembly 62, so that fluid flows as indicated by arrows 82. Simultaneously, the pressure in the second working chamber 46, and thus in the channels 214 in the end plate 191, pushes the floating piston 193 into the released position, thereby resetting the frequency-dependent damper assembly 66 for the next cycle. When the floating piston 193 is in the released position during a compression stroke, fluid flows from the second working chamber 46 through the channels 214 in the end plate 191, through the frequency-dependent damper assembly 66, and into the first working chamber 44.

[0056] Fig. Figure 11 illustrates a fluid flow through the frequency-dependent damper assembly 66 when the shock absorber 20 is subjected to a compression stroke. During a compression stroke, fluid flows from the piston chamber 190 through the recesses 192 along flow path F2 to the first storage chamber 194. A third fluid flow path 404 is also defined during the compression stroke of the piston assembly 32 when the fluid pressure in the second storage chamber 195 is higher than the fluid pressure in the first storage chamber 194, which moves the floating piston 193 into the raised position. The third fluid flow path 404 extends from the second working chamber 46 through the channels 214 in the end plate 191, between the lip 219 of the end plate 191 and the plate 218b of the floating valve assembly 215, and into the second storage chamber 195.Fluid flowing through the third fluid flow path 404 flows through the vent channel 196 in the floating piston 193 from the second storage chamber 195 to the first storage chamber 194. Fluid in the third fluid flow path 404 then flows through the check valve 104, through the channel 110 in the piston rod 34 and out into the first working chamber 44.

[0057] During the compression stroke, the pressure in the first working chamber 44, the channel 110, and the stage chamber 112 is lower than the pressure in the first storage chamber 194, allowing fluid to flow from the high-pressure to the low-pressure side through the check valve 104. The fluid presses the detent disc 288 against a spring force of the check valve 104, resulting in pressure relief within the first storage chamber 194. This allows the pressure in the first storage chamber 194 to be relieved.

[0058] Several features of the shock absorber 20 can be varied to tune the operating characteristics exhibited during frequency-dependent damping. For example, the check valve 104 provides throttling for fluid flowing through the piston rod 34 to the first storage chamber 194. The size of the orifice and / or the number of recesses in the check valve 104 is tunable and results in different frequency-dependent damping. It should be noted that the check valve 104 can be shaped as desired and manufactured from a number of different materials with varying degrees of flexibility. In the illustrated embodiments, the adaptive force of the piston sleeve 102 is exerted on the rebound valve assembly 64.However, it should be noted that the frequency-dependent damper assembly 66 could be configured such that the adaptive force of the piston sleeve 102 is exerted on the compression stage valve assembly 62.

[0059] The Fig. Figures 12-15 show alternative embodiments in which a floating disc 500 extends annularly around the spacer 209 at a position located longitudinally between the elastic element 201 on one side and the piston travel limiter 208 on the other. The floating disc 500 is movable longitudinally relative to the spacer 209. The elastic element 201 has a radius 502, and the floating disc 500 has a radius 504, which may be equal to the radius 502 of the elastic element. In these alternative embodiments, the piston sleeve 102 contacts the floating disc 500 instead of directly contacting the elastic element 201. Accordingly, the floating disc 500 transmits the adaptive force from the piston sleeve 102 to the elastic element 201. The design of the floating disc 500 can be varied to change the magnitude of the adaptive force exerted on the elastic element 201.For example, the thickness of the 500 mm floating disc can be varied to increase or decrease the magnitude of the adaptive force exerted on the elastic element. Fig. 13. The thickness of the floating disc 500' was reduced (i.e., the floating disc 500' is thinner), resulting in the application of a smaller adaptive force to the elastic element 201 without changing the design, size, or position of the piston travel limiter 208 and the piston sleeve 102. Fig. 14. The thickness of the 500" floating disc was increased (i.e., the 500" floating disc is thicker), resulting in the application of a larger adaptive force to the elastic element 201 without changing the design, size, or position of the piston travel limiter 208 and the piston sleeve 102. Fig. 15 the radius 504 of the floating disc 500''' was reduced and is therefore smaller than the radius 502 of the elastic element, which leads to the application of a smaller adaptive force to the elastic element 201 without changing the design, size or position of the piston travel limiter 208 and the piston sleeve 102.

[0060] Fig. Figure 16 is a diagram illustrating the frequency-dependent damping of the frequency-dependent damper assembly 66 during a rebound stroke. The vertical or y-axis of the diagram represents the adaptive force exerted by the piston sleeve 102 on the rebound valve assembly 64 in pounds (lbs.), and the horizontal or x-axis of the diagram represents the velocity of the piston rod 34 in meters per second (m / s). The dashed line 600 illustrates the relationship between force and velocity during a rebound stroke of a shock absorber 26 without the piston stroke limiter 208 disclosed herein. The force is high at higher velocities, which can create a blocking condition in which the rebound valve assembly 64 does not open and no fluid flows from the first working chamber 44 through the rebound flow channel 76 in the piston assembly 32 into the second working chamber 46.The solid lines 602 and 604 illustrate the relationship between force and velocity during a rebound stroke of the shock absorbers 26, which have the piston travel limiter 208 disclosed herein. The adaptive force exerted by the piston sleeve 102 on the rebound valve assembly 64 is lower in the high-speed section of the diagram, so no locking condition occurs. In the illustrated example, the solid line 602 corresponds to that shown in [reference missing]. Fig. 12 embodiment shown, while the solid line 604 of the in Fig. 13 corresponds to the embodiment shown. The thinner floating disc 500' in the embodiment of Fig.13 results in a reduced force being exerted on the rebound valve assembly 64. The dashed line 606 illustrates the frequency-dependent damping effects of the frequency-dependent damper assembly 66 disclosed herein, which includes the floating piston 193 and the vent channel 196. This design exerts less force on the rebound valve assembly 64 during low-speed rebound inputs.

Claims

[1] Damping system for a vehicle (10), comprising: a pressure tube (30) containing a hydraulic fluid; a piston rod (34) extending inside the pressure tube (30) along a longitudinal axis (35); a piston assembly (32) which is slidably fitted into the pressure tube (30) for movement along the longitudinal axis (35), wherein the piston assembly (32) is coupled to the piston rod (34) and separates the pressure tube (30) into a first working chamber (44) and a second working chamber (46), wherein the piston assembly (32) comprises a piston body (60) and a valve assembly (62, 64) which controls the fluid flow between the first working chamber and the second working chamber; a frequency-dependent damper assembly comprising a damper housing (100) coupled to the piston rod (34), a piston sleeve (102) comprising a substantially tubular element extending around an outer surface (113) of the damper housing (100) and movable longitudinally relative to the damper housing (100) along the longitudinal axis (35) between a rest position and an engagement position, and a piston chamber (190) arranged between the damper housing (100) and the piston sleeve (102), which is fluidically connected to at least one of the first working chamber and the second working chamber; wherein a pressure increase within the piston chamber (190) generates an adaptive force on the piston sleeve (102), which moves the piston sleeve (102) longitudinally in the direction of the piston assembly (32) into the engagement position, wherein the piston sleeve (102) contacts the valve assembly (62, 64) in the engagement position to transmit the adaptive force to the valve assembly (62, 64) and to increase the resistance of the valve assembly (62, 64) to opening; and a piston travel limiter (208) which is positioned longitudinally between the damper housing (100) and the valve assembly (62, 64) and which touches the piston sleeve (102) when the piston sleeve (102) is in the engagement position in order to limit the longitudinal movement of the piston sleeve (102) in the direction of the piston body (60) and to limit the adaptive force exerted by the piston sleeve (102) on the valve assembly (62, 64). [2] Damper system according to claim 1, wherein the valve arrangement (62, 64) has a floating support disc (200) which is fitted to slide on the piston rod (34) for movement along the longitudinal axis (35), wherein the floating support disc (200) is positioned in the longitudinal direction between the piston travel limiter (208) and the piston body (60). [3] Damper system according to claim 2, wherein the valve arrangement (62, 64) comprises an elastic element (201) coupled to the piston rod (34) between the floating support disc and the piston travel limiter (208), wherein the elastic element is positioned to exert a preload force on the floating support disc (200) which preloads the floating support disc (200) in the direction of the piston body (60). [4] Damper system according to claim 3, wherein the piston sleeve (102) contacts the elastic element in the engagement position to transmit the adaptive force to the elastic element and to increase the preload force exerted by the elastic element on the floating support disc (200). [5] Damper system according to claim 4, wherein the elastic element is a disc spring (201) and wherein the floating support disc (200) has an outer rim (204) and a cavity (203) for the floating support disc (200) which is positioned radially between the piston rod (34) and the outer rim (204), wherein the cavity (203) of the floating support disc is positioned to at least partially accommodate the elastic element when the elastic element bends as the floating support disc (200) moves longitudinally along the longitudinal axis (35) in the direction of the damper housing (100). [6] Damper system according to claim 3, wherein the piston body (60) has at least one flow channel (74, 76) which is arranged in fluid communication with the first and the second working chamber, and wherein the valve arrangement (62, 64) has at least one valve plate (78, 86) which is elastic and controls the fluid flow through the at least one flow channel (74, 76) in the piston body (60) by closing and opening the at least one flow passage depending on the fluid pressure in the first and the second working chamber and the preload force which the elastic element exerts on the floating support disc (200). [7] Damper system according to claim 3, further comprising: a floating disc (500) which is fitted slidably on the piston rod (34) for movement along the longitudinal axis (35), wherein the floating disc (500) is positioned longitudinally between the piston travel limiter (208) and the elastic element. [8] Damper system according to claim 1, wherein the piston travel limiter (208) has at least one tab (211) extending radially outwards in the direction of the pressure tube (30), and the piston sleeve (102) has at least one notch (212) positioned such that it slidably receives the at least one tab (211) of the piston travel limiter (208) when the piston sleeve (102) moves longitudinally relative to the piston travel limiter (208) along the longitudinal axis (35) between the rest position and the engagement position. [9] Damper system according to claim 8, wherein the at least one notch (212) includes an insert surface (213) which contacts the at least one tab (211) of the piston travel limiter (208) when the piston sleeve (102) is in the engagement position, thereby preventing the piston sleeve (102) from moving further towards the piston body (60). [10] Damper system according to claim 9, wherein the at least one notch (212) has an L-shaped profile (223) and has a longitudinal section (225) and a circumferential section (227) and wherein the at least one tab (211) of the piston travel limiter (208) is positioned in the circumferential section (227) of the at least one notch (212).

Images