Patent Publication Number: US-2023160450-A1

Title: Linear and Progressive Valve Assemblies For Digressive Shock Absorber

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     FIELD OF INVENTION 
     The present general inventive concept relates to hydraulic shock absorbers, and, more particularly, to an improved damping valve stack in a hydraulic shock absorber. 
     BACKGROUND 
     Hydraulic shock absorbers dampen the release of energy stored in a compressed spring. Typically, a piston with orifices formed therein is forced through a reservoir of oil, and the resistance of the oil to flow through the orifices increases as the piston&#39;s velocity, or shaft velocity, through the oil increases. Shaft velocity is the result of vertical wheel speed during suspension movements. It is the relationship between shaft velocity and damping force that defines a shock absorber&#39;s performance (valving). Deflective disk valving was developed as a way to spring load the orifices of the piston, which increased damping forces at slow shaft velocities, and at the same time eliminated the excessive forces created by high-speed shaft movements. The result of such valving was a more linear response to shaft velocity, as opposed to the progressive (nearly exponential) response of the early technology. Another development was digressive valving, which is substantially the opposite of progressive, wherein the rate of increase of damping force begins to digress, relative to shaft velocity, past a certain point of the shaft velocity. Shocks can have such a digressive response on compression of the shock, rebound, or both, depending on the piston design. With digressive valving, undesirable high-speed damping forces can be eliminated without sacrificing low speed control. In modern technology both linear and digressive pistons are utilized to achieve optimum performance in a wide variety of racing and OEM markets. Such tuning of the shocks can affect performance and handling on wide ranges of bumps and other irregular road/track surfaces. Typically, a digressive valving will sacrifice a smooth ride for increased control at lower forces, and the force response will begin to level off relatively with higher shaft velocity, while linear valving will sacrifice some handling at the lower shaft velocities, and maintain a relatively linear force response as the shaft velocity increases. With this in mind, it may be desirable to develop a shock absorber that could combine different and tunable linear, digressive, and/or progressive responses. 
     BRIEF SUMMARY 
     According to various example embodiments of the present general inventive concept, a shock absorber valve assembly is provided that includes a linearizing plate configured to add linearization damping characteristics to a digressive bypass assembly, and/or a progressive support disk configured to add progressive damping characteristics to a linear valve assembly. 
     Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the present general inventive concept. 
     The foregoing and/or other aspects and advantages of the present general inventive concept may be achieved by providing a valving assembly to cause linear damping response in a shock absorber having a digressive piston, the valving assembly including a linearizing plate having a first side configured to contact a ridge of a digressive piston proximate an outer edge of the first side, a second side, opposite the first side, configured to have a substantially flat surface, and a plurality of flow openings configured to allow fluid flow between the first and second sides of the linearizing plate. 
     The foregoing and/or other aspects and advantages of the present general inventive concept may also be achieved by providing a valving assembly to cause progressive damping response in a shock absorber having a linear piston face, the valving assembly including a support disk configured to be located at an end of the valving assembly opposite a piston of the shock absorber, and a metering shim configured to be placed adjacent to the support disk, wherein a side of the support disk facing the piston is configured with a stepped down recess configured to seat the metering shim therein, and wherein the metering shim is configured to have a smaller diameter than a cover shim arranged between the support disk and the piston so as to provide a predetermined gap between the support disk and the cover shim. 
     Other features and aspects may be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The following example embodiments are representative of example techniques and structures designed to carry out the objects of the present general inventive concept, but the present general inventive concept is not limited to these example embodiments. In the accompanying drawings and illustrations, the sizes and relative sizes, shapes, and qualities of lines, entities, and regions may be exaggerated for clarity. A wide variety of additional embodiments will be more readily understood and appreciated through the following detailed description of the example embodiments, with reference to the accompanying drawings in which: 
         FIG.  1    illustrates an assembled view of a typical shock absorber piston assembly; 
         FIG.  2    illustrates an exploded view of a conventional shock absorber piston assembly having a digressive compression and rebound assembly; 
         FIG.  3    illustrates an exploded view of a linearized digressive compression assembly according to an example embodiment of the present general inventive concept; 
         FIG.  4 A  illustrates an exploded view of a portion of the compression assembly components of  FIG.  3    along with a digressive piston, and  FIG.  4 B  illustrates a plan view of a linearizing plate according to an example embodiment of the present general inventive concept; 
         FIGS.  5 A-B  respectively illustrate exploded and assembled cross-sections of the compression assembly components of  FIG.  4 A ,  FIG.  5 C  illustrates a partially exploded cross-section of an additional linearizing plate assembly being provided on the rebound side of the digressive piston according to an example embodiment of the present general inventive concept, and  FIG.  5 D  illustrates a cross-section of the assembled components of  FIG.  5 C ; 
         FIG.  6    illustrates an exploded view of a conventional shock absorber piston assembly having a linear compression and rebound assembly; 
         FIG.  7 A  illustrates an exploded view of a linear compression assembly having a progressive damping element according to an example embodiment of the present general inventive concept, and  FIG.  7 B  illustrates an exploded view of progressive damping elements provided in both linear compression and rebound assemblies according to an example embodiment of the present general inventive concept; 
         FIG.  8    illustrates an exploded view of a portion of the compression assembly components of  FIG.  7 A ; 
         FIGS.  9 A-B  respectively illustrate exploded and assembled cross-sections of the compression assembly components of  FIG.  8   ; and 
         FIG.  10    illustrates a cross-section of the compression assembly components of  FIG.  9 B  showing flexure of the cover shim toward a progressive support disk in response to force of fluid flow. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the example embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings and illustrations. The example embodiments are described herein in order to explain the present general inventive concept by referring to the figures. 
     The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the structures and fabrication techniques described herein. Accordingly, various changes, modification, and equivalents of the structures and fabrication techniques described herein will be suggested to those of ordinary skill in the art. The progression of fabrication operations described are merely examples, however, and the sequence type of operations is not limited to that set forth herein and may be changed as is known in the art, with the exception of operations necessarily occurring in a certain order. Also, description of well-known functions and constructions may be simplified and/or omitted for increased clarity and conciseness. 
     Note that spatially relative terms, such as “up,” “down,” “right,” “left,” “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over or rotated, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     In shock assemblies, “bleed” is how much fluid a shock will bypass through a piston and valve stacks as it moves in either direction (compression and rebound). With a linear piston having a substantially flat face, a small bleed hole in the piston, along with a pyramid stack of valving disks, produces a linear damping response. With a digressive piston having a piston ring or ridge and corresponding lowered area or recess within the ridge allowing preloading of the pyramid stack, small valving disks may be placed in the recess to decrease the preload and simulate a linear damping response. Linear pistons may have more and larger bleed holes, and multiple pyramid stacks of valving disks, to produce a progressive damping response, while sacrificing low speed control. 
     In digressive valve stacks the bypass disk, or bypass bleed plate, affects low to mid-range rebound. The amount of bypass built into either linear or digressive valvings directly affects the low speed performance. With linear designs the bypass flow is balanced with the strength of the valve stack. It is the amount of bypass area that sets the parameters for the valve stack design with both linear and digressive pistons. In some configurations the bypass plate&#39;s thickness and number of slots, or flow openings, in its perimeter determine the bypass area. Testing has shown that more bypass area in the valve stack means less low speed damping force, and less bypass area means more low speed damping force. In other configurations the bypass plate, or bypass shim, is formed by a cover plate such that the cover plate diameter determines the bypass area due to open area of fluid holes. Typically, in such a valve stack, there are a variety of shims that are ordered (moving away from the piston) as a pre-load shim, the bypass shim, the cover shim, and a support shim. The number of various ones of these shims, as well as the diameters and thicknesses, vary according to different particular valve stacks. In a standard digressive stack, with the pre-load plate next to the piston, more thickness of the pre-load plate causes the cover plate to have less pre-load, and therefore less overall damping force in the stack. The bleed plate controls the low-speed damping forces, wherein more total bleed area means less damping force, and less bleed means more damping force. The cover plate or shim determines the overall force of the stack once the stack opens. Until the stack opens, only the bleed effects the valving. The support plate or brake washer fine tunes the high-speed damping force. 
     Various example embodiments of the present general inventive concept may provide a novel valve stack that improves performance by providing a shock absorber valve assembly that includes a linearizing plate, or linearization conversion plate, configured to add linearization damping characteristics to a digressive bypass assembly, and/or a progressive support disk configured to add progressive damping characteristics to a linear valve assembly. It is noted that the terms shock and shock absorber may be used interchangeably in the descriptions that follow. The terms disk, shim, plate, etc., may also be used interchangeably in portions of these descriptions. 
       FIG.  1    illustrates an assembled view of a typical shock absorber piston assembly. As illustrated, the shock absorber piston assembly  100  includes a piston rod  104  on with a piston/valving assembly  106  mounted thereon. The piston/valving assembly  106  has compression assembly valving on one side of the piston, and rebound assembly valving on the other side of the piston. 
       FIG.  2    illustrates an exploded view of a conventional shock absorber piston assembly having a digressive compression and rebound assembly. It is noted that many of the drawings shown herein, including  FIG.  2   , show the shock absorber piston assembly in an inverted view, or upside down relative to how they would be arranged when installed, simply to better show various piston side characteristics of some of the components of the assembly. As illustrated in  FIG.  2   , a digressive piston  156  is provided with a compression assembly  108  on one side, and a rebound assembly  168  on the other side. Digressive pistons are formed with a ridge on the surface, and a corresponding recess formed inside the piston ridge and having a plurality of bleed or flow openings, which allows pre-loading of shims to affect the damping curve. Digressive shocks are produced by preloading the valve disks, typically between 0.002″ and 0.015″, in the recess inside the surface ridge on the digressive piston. The amount of preload changes the breakover point of the damping curve. Small variations in the preload thickness of these valve disk stacks may produce highly varying damping loads. Linear shocks have a flat surface of the piston, and thus variations in the valve disks are needed to try and create the desired damping curve, which will be described herein. 
     The compression assembly  108  of this shock is a conventional digressive compression only bypass assembly including (listed in order in the direction of the piston  156 ) a support disk  112 , a pair of clamp shims  116 , a support shim  120 , another support shim  122  of larger diameter than the support shim  120 , a cover shim  124 , a bleed shim  128  having a plurality of bleed openings  132  arranged around a perimeter of the bleed shim  128 , a preload shim  136 , a check valve spring  144 , and a check valve plate  148  that is configured to be received in a recessed ring on the compression side face of the piston  156 . The check valve spring  144  and check valve plate  148  form a check valve assembly  140 . The check valve plate  148  is a compression only bypass (COB) valve. 
     The rebound assembly  168  of this shock, located on the rebound side of the piston  156 , includes (in order leading away from the piston  156 ) a preload shim  172 , a bleed shim  176  having a bleed opening  180  located on a perimeter of the bleed shim  176 , a cover shim  184 , a support shim  188 , a pair of clamp shims  192 , and a brake washer  196 . A nut  200  is arranged to hold the piston assembly together on the piston rod  104 . 
     During a compression operation of the shock, the check valve plate  148 , which is configured to be seated in a corresponding recess of the digressive piston  156  to inhibit fluid flow through flow openings formed in that recess of the digressive piston  156 , opens up to allow more fluid to flow. The bleed is additive, and in this example assembly the flow openings in the bleed shim  128  in the compression assembly  108  are equal to approximately 6 mm 2 , and the opening in the bleed shim  176  in the rebound assembly  168  is equal to approximately 0.27 mm 2 . Thus, during compression, this shock assembly has 6.27 mm 2  of bleed area. When it is rebounding, the check valve spring  144  causes the check valve plate  148  to full seat in the digressive piston  156 , shutting the flow openings formed in the recess that receives the check valve plate  148 . Thus, there is only 0.27 mm 2  of bleed area in the rebound. This is generally the configuration found in the BILSTEIN COB digressive piston assembly. 
       FIG.  3    illustrates an exploded view of a linearized digressive compression assembly according to an example embodiment of the present general inventive concept. In this example embodiment, a compression assembly  212  includes many of the same components as the conventional compression assembly  108  illustrated in  FIG.  2   , but the bleed shim  128  and preload shim  136  have been replaced by a linearizing plate  216  that is configured to cause linear damping response of the digressive piston assembly. 
       FIG.  4 A  illustrates an exploded view of a portion of the compression assembly components of  FIG.  3   . In the example embodiment illustrated in  FIG.  4 A , the linearizing plate  216  is configured with a first side  220  that is arranged to face the piston  156 , and a second side  224 , that has a substantially flat surface, opposite the first side  220  of the linearizing plate  216  and arranged to face away from the piston  156 . The first side  220  of the linearizing plate  216  is formed with an inner surface  232  formed around the central hole that receives the piston rod  104 , an outer ridge  228 , and a channel  236  formed between the inner surface  232  and outer ridge  228 . A plurality of flow holes  240  are formed in the channel  236  to allow fluid flow therethrough during travel of the piston  156  through the shock absorber. The outer ridge  228  of the first side  220  of the linearizing plate  216  is configured to contact a ridge  260  (illustrated in  FIGS.  5 A-B ) on the corresponding side of the digressive piston  156  to prohibit any of the fluid flowing through the plurality of flow holes  240  in the channel  236  from going outside of the ridge  260  of the digressive piston  156  when the linearizing plate  216  is moved into contact with the piston  156 . In various example embodiments, such as illustrated in  FIGS.  4 A and  4 B , a gasket or sealing ring  244  can be provided on a surface of the outer ridge  228  of the linearizing plate  216  to form a seal with the ridge  260  of the digressive piston  156  to aid in the prevention such fluid flow. In various example embodiments a groove  248  may be formed on the outer ridge  228  to seat the sealing ring  244  therein, while in other example embodiments the sealing ring  244  may be simply adhered to the flat surface of the outer ridge  228 .  FIG.  4 B  illustrates a plan view of the first side (piston facing side)  220  linearizing plate  216  according to an example embodiment of the present general inventive concept. In various example embodiments of the present general inventive concept, the inner surface  232  on the first side  220  of the linearizing plate  216  may project higher over the channel  236  than does the outer ridge  228 , to better interact with the check valve spring  144  and check valve plate  148  of the compression assembly  212  when the linearizing plate  216  is pressed toward the digressive piston  156 . When such contact is made, the flat surface of the second side  224  of the linearizing plate  216  effectively forms a flat face of the piston  156 , increasing linear damping force of the compression assembly  168  when so arranged. The linearizing plate  216  can be used on either or both sides of the digressive piston to increase linear damping response. A conventional linear stack may be provided on the side of the linearizing plate  216  opposite the piston, with the bleed set by the diameter of a cover shim relative to the flow openings formed on that side of the linearizing plate  216 . 
       FIGS.  5 A-B  respectively illustrate exploded and assembled cross-sections of the compression assembly components of  FIG.  4 A ,  FIG.  5 C  illustrates a partially exploded cross-section of an additional linearizing plate assembly being provided on the rebound side of the digressive piston according to an example embodiment of the present general inventive concept, and  FIG.  5 D  illustrates a cross-section of the assembled components of  FIG.  5 C . As illustrated in FIGS. SA-B, when the linearizing plate  216  and digressive piston  156  are forced together, the check valve spring  144  and check valve plate  148  are captured inside a piston recess  256  formed inside the piston ridge  260 , restricting some of the fluid flow through the inner flow openings  252  on the compression side of the digressive piston  156 . The digressive piston  266  illustrated in FIGS. SA-D is formed on one side with a circular channel  266  inside the piston recess  256  to work with a COB valving assembly. The channel  266  has an outer lip  258  and an inner lip  262  formed at a “bottom” of the channel  266 , i.e., the deep part of the channel  266 , on which the check valve plate  148  rests when biased in the direction of the piston  156  by the check valve spring  144 . The inner portion of the check valve spring  144  is effectively sandwiched between the inner surface  232  of the linearizing plate  216  and the center portion of the piston  156  rising an inner border of the channel  266 . With a digressive piston such as the piston  156 , the inner flow openings  252  formed inside the piston ridge on one side of the digressive piston lead to outer flow openings  254  formed outside the piston ridge on the other side of the digressive piston. Roughly speaking, there is approximately 150 mm 2  of flow area going in both directions through the digressive piston  156 . The check valve plate  148  is configured to be seated in the piston channel  266  by the check valve spring  144  to restrict fluid flow through the flow openings in the piston recess  256  during some phases of the shock response. As illustrated in  FIG.  5 B , with the linearizing plate  216  pressed against the digressive piston  156 , the sealing ring  244  on the outer ridge  228  of the linearizing plate  216  forms a seal with the piston ridge  260 , preventing flow from either side over the piston ridge  260  itself. The channel  236  is configured to allow fluid flow about the edges of the check valve plate  148  and through the inner flow openings  252  of the digressive piston  156 . As also illustrated in  FIG.  5 B , when the linearizing plate  216  is pressed fully against the digressive piston  156 , the flat second side  224  of the linearizing plate  216  effectively forms a linear piston face, causing linear response of the digressive piston  156 . While the linearizing plate  156  forming a linear face on a digressive piston  156  is only shown on the compression side in this illustrated example, it could just as easily be located on the rebound side of the digressive piston, or on both sides of the digressive pistons (as illustrated in  FIGS.  5 C-D ). As illustrated in  FIG.  5 B , the flow holes  240  of the linearizing plate  216  are configured to channel fluid to the inner flow openings  252  of the digressive piston, thus providing similarly configured linear piston faced flow openings. A conventional linear stack, with the bleed set by the diameter of the cover shim  124  covering the flow holes  240 , can therefore be provided on the flat second side  224  of the linearizing plate  216 , as illustrated in  FIG.  3   . In various example embodiments, the flow holes  240  of the linearizing plate  216  may be configured to have 150 mm 2  of flow area, to match the flow area of the digressive piston  156 . As illustrated in  FIGS.  5 C-D , the linearizing plate  216  can also be used on the rebound side of the digressive piston  156  to cause a linear damping response on the rebound side as well. Although the rebound side of the digressive piston  156  has the piston ridge  260  which allows the digressive characteristics, the rebound side does not have the channel  266  to accommodate the check valve assembly  140  that is provided in the compression assembly  212  of  FIG.  3   . Therefore, instead of having a check valve spring  144  and check valve plate  148  between the linearizing plate  216  and the digressive piston  156 , a preload shim  136  may be placed between the linearizing plate  216  and the digressive piston  156 . The preload shim  136  is held between the inner surface  232  of the linearizing plate  216  and the extending central portion of the digressive piston  156  inside the rebound side piston ridge  260 . The size of the preload shim  136  may be chosen to cause the desired blow characteristics through the linearizing plate  216  and digressive piston  156 . Otherwise, the fit and operation of the linearizing plate  216  on the rebound side of the digressive piston  156  is much the same as that on the compression side. Thus, the linearizing plate  216  may be used on either or both sides of a digressive piston. 
       FIG.  6    illustrates an exploded view of a conventional shock absorber piston assembly having a linear compression and rebound assembly. As illustrated in  FIG.  6   , a linear piston  284  is provided with a compression assembly  264  on one side, and a rebound assembly  296  on the other side. The compression assembly  264  of this shock is a conventional linear compression assembly including (listed in order in the direction of the piston  284 ) a support disk  268 , a pair of clamp shims  272 , a support shim  276 , another support shim  278  having a larger diameter than the support shim  276 , and a cover shim  280  configured to contact the compression side of the linear piston  284 . 
     The rebound assembly  296  of this shock, located on the rebound side of the piston  284 , includes (in order leading away from the piston  284 ) a cover shim  300 , a plurality of support shims  304  formed with decreasing diameter moving away from the rebound side of the piston  284 , a pair of clamp shims  308 , and a brake washer  312 . A nut  200  is arranged to hold the piston assembly together on the piston rod  104 . 
     The basic difference between the linear piston  284  and the digressive piston  156  is the flat surface of the linear piston  284 . Because the linear piston  284  does not have the piston ridge  260  and corresponding piston recess  256  inside the ridge  260 , there is no way to pre-load the shims. The linear piston  284  works by the cover shims on the flat surface of the linear piston  284  simply opening, and from the diameter of the cover shims, which determine how much of the flow openings in the linear piston  284  are covered by the cover shims. 
       FIG.  7 A  illustrates an exploded view of a linear compression assembly having a progressive damping element according to an example embodiment of the present general inventive concept, and  FIG.  7 B  illustrates an exploded view of progressive damping elements provided in both linear compression and rebound assemblies according to an example embodiment of the present general inventive concept. In the example embodiment illustrated in  FIG.  7 A , a compression assembly  324  includes many of the same components as the conventional compression assembly  264  illustrated in  FIG.  6   , but the support disk  268  has been replaced by a progressive support disk  328 , or progressive plate, that is configured to increase progressive damping response of the linear piston assembly. In this example embodiment one of the clamp shims  272  of the compression assembly  264  of  FIG.  6    has also been omitted, and a metering shim  332  has been added to interact with the progressive support disk  328  to tune the damping effect of the progressive support disk  328 . Such tuning may be done by using different thickness of the metering shim  332 , and/or providing different quantities of metering shims. As illustrated in  FIG.  7 B , a rebound assembly  326  may include substantially the same components as the compression assembly  324 , in a mirror image leading away from the linear face piston  284 . Therefore, a valving assembly including the progressive support disk  328  may be located on either or both the compression and rebound sides of the linear piston  284 . 
       FIG.  8    illustrates an exploded view of a portion of the compression assembly  324  components of  FIG.  7 A . As illustrated in  FIG.  8   , the cover shim  280 , support shims  278  and  276 , and clamp shim  272  decrease in diameter in a direction away from the linear piston  284 , this portion of the compression assembly  324  ending with the metering shim  332  and progressive support disk  328 . The side of the progressive support disk  328  facing the piston  284  is formed to be stepped down twice in the direction of the opening through which the piston rod  104  passes through the progressive support disk  328 . As illustrated in  FIG.  8   , the side of the progressive support disk  328  facing the piston  284  is configured with an outer surface  334  forming an outer perimeter of that side of the progressive support disk  328 , a middle surface  336  stepped down from the outer surface  334 , and an inner surface  338  stepped down from the middle surface  336 . The inner surface  338  of the progressive support disk  328  is configured to seat the metering shim  332  therein. Thus, instead of having a flat surface, such as that shown on the piston side of the support disk  268  of  FIG.  6   , the progressive support disk  328  has a progressive surface. Therefore, by replacing the support disk  268  with the progressive support disk  328  and metering shim  332 , a linear damping response can be made more progressive. 
       FIGS.  9 A-B  respectively illustrate exploded and assembled cross-sections of the compression assembly components of  FIG.  8   . As illustrated in  FIGS.  9 A-B , a thickness of the metering shim  332  determines the amount of a vertical gap  340  between the cover shim  280  and the outer surface  334  of the progressive support disk  328 . The gap  340  can be made greater by increasing the thickness of the metering shim  332 , or metering shims  332 , or can be made smaller by decreasing the thickness of the metering shim(s)  332 . When the force on the cover shim  280  is sufficient to flex the edges of the cover shim  280  so as to contact the outer surface  334  of the progressive support disk  328 , the flow window is then fixed.  FIG.  10    illustrates a cross-section of the compression assembly components of  FIG.  9 B  showing the flexure of the cover shim  280 , as well as the support shims  276  and  278 , toward the progressive support disk  328  in response to force of fluid flow. From the point at which the cover shim  280  contacts the progressive support disk  328 , the flow window will not change. From that point on, there will a progressive change in the compression force, which in some example embodiments will be of some polynomial approximate to cubed. Although the progressive assembly of this example embodiment is illustrated as being located on the compression side of the piston, it could also be arranged on the rebound side, or on both sides of the piston. With various example embodiments of the present general inventive concept using such a progressive support disk, progressive compression can be achieved independently from what bleed is chosen, or what clamp shim diameter is present, and the assembler is given more flexibility in the support shim stack between the progressive support disk and the piston. By varying the gap  340 , the progressive response at a given shaft speed may be as much as tripled, or more. For example, a typical digressive piston valved to make 125 pounds of force at 10 inches/s of shaft velocity may make 165 pounds of force at 20 inches/s of shaft velocity. A true linear assembly valved to make 125 pounds of force at 10 inches/s of shaft velocity will make approximately 250 pounds of force at 20 inches/s of shaft velocity. An assembly employing a progressive support disk of the present general inventive concept that makes 125 pounds of force at 10 inches/s may make, for example, as much as 400-500 pounds of force at 20 inches/s of shaft velocity. 
     Thus, a stepped progressive support disk with a metering shim as described herein can be used in place of a conventional support disk. The metering shim may be used to set a gap between a cover shim and the progressive support disk, and the gap can be varied by changing the thickness of the metering shim or metering shims. When the cover shim flexes enough to come in contact with the progressive support disk, the flow window is fixed, and from that point on a progressive force response is achieved. In this way, progressive compression is achieved independently of a chosen bleed or clamp shim diameter, and flexibility is added in the stack underneath, in the support disk. 
     In various example embodiments a metering shim  332  may be provided adjacent to a conventional support disk  268  having a flat surface to produce the aforementioned gap between the cover shim  280  and the support disk  268 , and to thus introduce progressive damping force to a linear stack assembly. 
     Various example embodiments of the present general inventive concept may provide a valving assembly to cause linear damping response in a shock absorber having a digressive piston, the valving assembly including a linearizing plate having a first side configured to contact a ridge of a digressive piston proximate an outer edge of the first side, a second side, opposite the first side, configured to have a substantially flat surface, and a plurality of flow openings configured to allow fluid flow between the first and second sides of the linearizing plate. The first side of the linearizing plate may be configured to contact the ridge of the digressive piston so as to prohibit fluid flow between the first side of the linearizing plate and the ridge of the digressive piston. The valving assembly may further include a sealing ring provided proximate the outer edge of the first side of the linearizing plate and configured to seal a space between the first side of the linearizing plate and the ridge of the digressive piston. The first side of the linearizing plate may include an outer ridge, an inner surface, and a channel formed between the outer ridge and inner surface, the plurality of flow openings being located in the channel. The valving assembly may further include a sealing ring provided on the outer ridge and configured to seal a space between the outer ridge of the linearizing plate and the ridge of the digressive piston. The valving assembly may further include a groove formed on the outer ridge and configured to at least partially receive the sealing ring. The inner surface may project higher than the outer ridge. The inner surface may be configured to compress a check valve spring and check valve plate against a surface of the digressive piston inside the ridge of the digressive piston. The flow openings may be configured to have substantially the same flow area as a flow area of the digressive piston inside the ridge of the digressive piston. The plurality of flow openings may be configured to allow control of bleed by varying an outer diameter of an adjacent cover shim. The valving assembly may further include another linearizing plate arranged on a ridge on an opposite side of the digressive piston in a substantially mirrored arrangement, so as to form a split-bleed linear piston assembly with the digressive piston. 
     Various example embodiments of the present general inventive concept may provide a valving assembly to cause progressive damping response in a shock absorber having a linear piston face, the valving assembly including a support disk configured to be located at an end of the valving assembly opposite a piston of the shock absorber, and a metering shim configured to be placed adjacent to the support disk, wherein a side of the support disk facing the piston is configured with a stepped down recess configured to seat the metering shim therein, and wherein the metering shim is configured to have a smaller diameter than a cover shim arranged between the support disk and the piston so as to provide a predetermined gap between the support disk and the cover shim. The side of the support disk facing the piston may include an outer surface, a middle surface stepped down from the outer surface, and an inner surface stepped down from the middle surface, wherein the inner surface is configured to seat the metering shim therein. The middle surface may be configured to have a diameter larger than a plurality of shims between the support disk and the cover shim, such that the cover shim contacts the outer surface when the cover shim flexes so as to contact the support disk. The valving assembly may be provided on both sides of the linear piston to cause progressive damping response on both compression and rebound sides of the linear piston. The linear piston face may be formed by a linearizing plate provided adjacent to a linear piston. Thus, valving assemblies on both the compression and rebound sides of a piston may include the linearizing plate and/or progressive support disk, depending on the type of piston and desired responses. 
     Numerous variations, modifications, and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of the present general inventive concept. For example, regardless of the content of any portion of this application, unless clearly specified to the contrary, there is no requirement for the inclusion in any claim herein or of any application claiming priority hereto of any particular described or illustrated activity or element, any particular sequence of such activities, or any particular interrelationship of such elements. Moreover, any activity can be repeated, any activity can be performed by multiple entities, and/or any element can be duplicated. 
     It is noted that the simplified diagrams and drawings included in the present application do not illustrate all the various connections and assemblies of the various components, however, those skilled in the art will understand how to implement such connections and assemblies, based on the illustrated components, figures, and descriptions provided herein, using sound engineering judgment. Numerous variations, modification, and additional embodiments are possible, and, accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of the present general inventive concept. 
     While the present general inventive concept has been illustrated by description of several example embodiments, and while the illustrative embodiments have been described in detail, it is not the intention of the applicant to restrict or in any way limit the scope of the general inventive concept to such descriptions and illustrations. Instead, the descriptions, drawings, and claims herein are to be regarded as illustrative in nature, and not as restrictive, and additional embodiments will readily appear to those skilled in the art upon reading the above description and drawings. Additional modifications will readily appear to those skilled in the art. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.