Valve arrangement for a shock absorber comprising a triple spring device

Abstract

The present disclosure relates to a valve arrangement for a shock absorber. The valve arrangement comprises a valve member axially movable relative to a housing and a triple spring arrangement comprising a first spring, a second spring and a coil spring arranged between the valve member and a coupling member coupled to the first spring and the second spring. The valve arrangement is adapted such that when the valve member is moved relative to a predetermined reference position by no more than a first stroke length, the first spring deflects to adjust a force balance of the valve member, when the valve member is moved beyond the first stroke length, the second spring deflects to adjust said force balance, and when the valve member is moved beyond a second stroke length greater than the first stroke length, the coil spring compresses to adjust said force balance. A shock absorber comprising such a valve arrangement and a method for controlling the flow of damping medium in a shock absorber are also disclosed.

Description

TECHNICAL FIELD

[0001] The present invention relates to a valve arrangement for a shock absorber for regulating the flow of damping medium between damping chambers of the shock absorber, and in particular to a valve arrangement comprising a triple spring arrangement enabling a desired damping force characteristic. BACKGROUND

[0002] Spring arrangements consisting of a weak spring and a hard spring, where the weak spring biases the hard spring and contributes to different spring qualities in different parts of the stroke, are used in many technical structures, such as in valves intended to control the flow of damping medium in a shock absorber. In particular in shock absorber applications, where the valve must have a precise damping pressure level without adjustable means, a low spring constant just at the beginning of the stroke is important. The low spring constant then transitions into a higher spring constant, which matches the high pressure that can occur in the shock absorber at fast movements.

[0003] EP 2201262 A1 describes a known design within the technical field of the invention.

[0004] It is desirable to improve the known designs so that a desired damping force characteristic can be achieved. However, some known inventions are difficult to provide a reliable solution due to poor tolerances of the springs intended to be used. Some solutions also provide solutions that occupy a considerable space in the limited space in a shock absorber.

[0005] Some solutions provide solutions that provide acceptable damping force characteristics in certain stroke length intervals, while sacrificing the quality of the damping force characteristics in other stroke length intervals.

[0006] There is therefore a need for an improved valve arrangement for a shock absorber that at least mitigates some of these problems. SUMMARY

[0007] It is an object of the present invention to provide an improved solution that mitigates the above-mentioned drawbacks of existing solutions. Furthermore, it is an object to provide a valve arrangement for a shock absorber that is able to provide a desired damping force characteristic. Here, the desired damping force characteristic can comprise a first damping force region with a slow increase in damping force in relation to a first stroke length interval, a second damping force region with a fast increase in damping force in relation to a subsequent second stroke length interval, and a third damping force region with a slower increase in damping force in relation to a further subsequent third stroke length interval. Furthermore, it is an object to provide a shock absorber incorporating such a valve arrangement, and it is also an object to provide a corresponding method for controlling the flow of damping medium between damping chambers of a shock absorber.

[0008] The present invention is based on the inventor's above-mentioned insight that the object can be achieved by incorporating a specifically designed triple spring arrangement in the valve arrangement. The triple spring arrangement comprises a helical spring, a first spring and a second spring, each adapted to deform in order to adjust the force balance of the valve member during different stroke length intervals corresponding to different damping force regions as mentioned above. The present invention further aims at providing a valve arrangement comprising a spring arrangement which is compact and simple and cheap to assemble, produce and adjust.

[0009] According to a first aspect of the present invention, a valve arrangement for a shock absorber is provided. The valve arrangement comprises a valve member which is axially movable relative to a housing, by which movement an opening defined by an interface between the valve member and a valve seat is adjusted. The valve arrangement comprises a spring arrangement. The spring arrangement comprises a first spring, a second spring and a helical spring arranged between the valve member and a coupling member coupled to the first spring and the second spring. The valve arrangement is adapted such that, when arranged in a shock absorber, a damping medium flow between damping chambers of the shock absorber is regulated by a force balance of the valve member, which force balance is partly or mainly generated by a damping medium pressure acting on the valve member depending on the damping medium flow and counteracting the action of the spring arrangement. The valve arrangement is further adapted such that, when the valve member is moved not more than a first stroke length relative to a predetermined reference position, the first spring is deflected to adjust said force balance, when the valve member is moved more than the first stroke length, the second spring is deflected to adjust said force balance, and when the valve member is moved more than a second stroke length greater than the first stroke length, the helical spring is compressed to adjust said force balance.

[0010] Hence, when the valve arrangement is arranged in a shock absorber accordingly, the damping force characteristic of the shock absorber is characterized according to the following at successively increasing stroke lengths: a first region of slowly increasing damping force corresponding to the first stroke length; a second region of rapidly increasing damping force corresponding to the second stroke length; a third region of slowly increasing damping force corresponding to a third stroke length greater than the second stroke length, which third stroke length is defined by the remaining stroke length that the valve member can be moved into the housing until being prevented from moving further.

[0011] More particularly, this desired damping force characteristic is achieved at least partly due to the spring arrangement comprising a first spring, a second spring and a helical spring, i.e. a triple spring arrangement, and how the spring arrangement is adapted to interact with the valve member when the valve member is moved relative to the housing.

[0012] As mentioned above, the valve member is adapted to engage with the valve seat. The valve seat can be a separate component from the housing. Further, the valve seat and the valve member can be adapted in shape and form to define a recess at their interface for distributing damping medium over a larger area at the interface. This can help to move the valve member in a controlled manner relative to the housing and away from the valve seat. The valve member can comprise a through hole axially aligned with the valve member, which is adapted to allow damping medium to flow through without forcing the valve member to be displaced relative to the valve seat.

[0013] As mentioned above, the valve arrangement is intended to regulate the flow of damping medium between the damping chambers of a shock absorber. The damping chambers can refer to the compression chamber and the rebound chamber. Further, the damping medium can flow through the opening defined by the interface between the valve member and the valve seat, thereby relieving the increased pressure build-up to some extent. In other words, the position of the valve member relative to the valve seat can regulate the flow of damping medium.

[0014] The coupling member can be adapted to facilitate the coupling of the helical spring with the first spring and the second spring. The coupling member can be adapted and mounted such that the first spring deflects before the second spring in response to the flow of damping medium and / or the movement of the valve member. The coupling member can represent a component of a triple spring arrangement, i.e. the spring arrangement can comprise the coupling member. The coupling member can be adapted to couple with the valve member, thereby maintaining the helical spring in place.

[0015] As mentioned, the first stroke length, the second stroke length and the third stroke length are measured relative to a predetermined reference position of the housing. The predetermined reference position refers to a position in the housing that is at least fixed during use. The stroke length of the valve member is then measured as the distance along the stroke path of the valve member in the housing, the valve member moving relative to said fixed position.

[0016] In the context of the present application, the expressions "slow" and "fast" used in association with the damping force in the different damping force regions should be understood to merely indicate the relation of the damping force behavior of the different damping force regions, i.e. the second damping force region is characterized by a more rapid increase of the damping force with respect to the stroke length compared to the damping force of the first and third damping force regions. Likewise, the first and third damping force regions are characterized by a more slow increase of the damping force with respect to the stroke length compared to the damping force of the second damping force region.

[0017] In the context of the present application, a "pressure responsive valve" should be understood as a valve adapted to achieve a larger flow opening in response to a pressure change. The pressure responsive valve can refer to a valve adapted to achieve a larger flow opening in response to an increase in pressure. Further, the pressure responsive valve can refer to a valve adapted to actuate from a closed state to an open state in response to a pressure change. Examples of pressure responsive valves can include a stack of shims, a poppet valve, etc.

[0018] In the context of the present application, low stroke speed, medium stroke speed and high stroke speed can primarily be seen as stroke speeds in the interval 0-1 m / s, 1-2 m / s and 2-4 m / s, respectively. Further stroke speeds above 4 m / s can be seen as included in the high stroke speed interval.

[0019] In the context of the present application, "arranged in series" is to be understood as object A and object B being arranged such that they are fluidly coupled to each other. The expression "fluidly coupled" is to be understood as object A being coupled to object B by any coupling means, such as a channel, a tube, a hose, or other connecting means through which a damping medium can flow. The coupling can be a direct coupling, or the coupling can be an indirect coupling. Furthermore, in the context of the present application, object A being "fluidly arranged between" object B and object C is to be understood as the placement of object A being in a fluid path extending between object B and object C. Thus, object A does not need to be "fluidly arranged" like floating.

[0020] In the context of the present application, "open state" is to be understood as object A being configured to allow a damping medium to flow through the object. Furthermore, "closed state" is to be understood as object A being configured to prevent a damping medium from flowing through the object.

[0021] In the context of the present application, "compression stroke" is to be understood as the movement of the piston head when it moves towards the compression chamber. Furthermore, "rebound stroke" is to be understood as the movement of the piston head when it moves towards the rebound chamber.

[0022] In the context of the present application, the expression "coupled to / coupled with" is to be understood as object A being mechanically connected to object B in some way, not necessarily directly mechanically connected - for example, there can be object C connecting object A with object B. Likewise, the expression "arranged between" and the like is to be understood as not being limited to the case where object C is arranged directly between object A and object B, but there can also be other objects D, E, etc. directly between object C and A and / or B.

[0023] According to one embodiment, the second spring has a higher spring constant than the first spring and the coil spring. This can constitute a way of ensuring that the first spring deflects before the second spring when the valve member is moved axially towards a higher stroke position. This has the advantage that it allows the triple spring arrangement to function as intended in a reliable and passive manner. A higher spring constant can be achieved due to differences in material and / or shape of the second spring relative to the first spring. For example, the second spring can be characterized by dimensions that are thicker, wider or shorter than the first spring.

[0024] According to a further embodiment, the helical spring is biased when the valve member is in a rest stroke position relative to the predetermined reference position. The rest stroke position can refer to when the valve member is engaged with the valve seat, i.e. rests on the valve seat. The helical spring can be biased between the coupling member and the valve member. The helical spring can be biased such that it only starts to compress after the first spring and the second spring have been deflected when the valve member is axially moved towards a higher stroke position. Further, the helical spring can be characterized by a spring constant which is lower than that of the second spring. This can represent a particular way of achieving a desired damping force characteristic. In addition, the spring constant of the helical spring can be equal to, higher than or lower than the spring constant of the first spring. The relationship and the magnitude of the difference can be adjusted in order to achieve a particular damping force characteristic in the first and third damping force regions. The rest stroke position can be a position which is axially offset relative to the predetermined reference position.

[0025] According to an embodiment, the coupling member is a spring cap which is adapted with latches for maintaining the bias of the helical spring while allowing it to be compressed in a controlled manner. Each respective latch can be arranged on a respective branch of the spring cap. Each respective branch can be flexible such that the latches can be displaced towards each other when being inserted into the valve member and when inserted, the latches engage with the valve member thereby maintaining the helical spring in a biased state. The length of the branches can determine how much the helical spring is biased when the valve member is in the rest stroke position. The spring cap can comprise two, three, four, five or more latches, each arranged on a respective branch. In a preferred embodiment, the spring cap comprises three latches.

[0026] According to an embodiment, the predetermined rest stroke position is adjustable by inserting an adjustment shim of a preferred thickness between the valve seat and the valve housing. Thereby, it can be adjusted whether and how much the first spring will be biased when the valve member is in the rest stroke position, which in turn enables the damping force characteristic to be adjusted to a desired characteristic. The valve seat can be adapted with a protrusion for engagement with the adjustment shim. The width of the adjustment shim then determines how much the valve seat will be offset from the housing, which in turn also adjusts how much the valve member will be adjusted according to position when in the rest stroke position. When the valve arrangement is assembled into a shock absorber, the valve seat will be offset relative to the housing by an offset distance corresponding to the thickness of the adjustment shim. Advantageously, the valve arrangement can be adapted to be configured with one or more of a set of adjustment shims, which can then be selected in order to achieve a particular offset distance and thereby a desired bias of the first spring. The valve arrangement can be configured with a plurality of such adjustment shims in order to achieve a desired bias of the first spring. The set of adjustment shims can comprise adjustment shims with a thickness of up to 1 mm.

[0027] According to an embodiment, both the first spring and the second spring are provided by deflectable pad spring portions of a single pad spring. Thereby, the triple spring arrangement can be provided in a more compact form factor. The pad spring can be a circular pad spring.

[0028] According to an embodiment, the first spring is provided by an outer pad spring portion forming an outer rim of the pad spring, and an inner pad spring portion separate from the outer pad spring portion and connected to the outer pad spring portion via a flexible branch, such that the outer pad spring portion and the inner pad spring portion are deflectable relative to each other by a first deflection distance corresponding to the first stroke length. The second spring is provided by the inner pad spring portion, and an innermost pad spring portion separate from the inner pad spring portion but connected to the inner pad spring portion via a flexible branch, such that the inner pad spring portion and the innermost pad spring portion are deflectable relative to each other by a second deflection distance corresponding to the second stroke length. With this design, the first spring and the second spring occupy less space in the axial direction. Furthermore, this design results in a beneficial synergy with the coil spring, which can be dimensioned in terms of spring constant and biasing accordingly, such that the intended functionality is achieved.

[0029] According to an embodiment, the coupling member is a spring cap comprising a protrusion adapted to press onto the innermost pad spring portion. The spring cap can comprise a main body and a protrusion extending out of said main body in the axial direction. The protrusion can be adapted to engage with one of the first spring and the second spring, which can then facilitate coupling therewith. Further, the main body can be adapted to engage with the first spring or the second spring in a limiting manner, i.e. how much the protrusion protrudes out of the main body in the axial direction can determine how much the first spring or the second spring can deflect. In other words, this can determine the length of the first stroke length or the second stroke length.

[0030] According to an embodiment, the deflection distance between the outer pad spring portion and the inner pad spring portion is created by the first spring being biased between a first fixed part in the valve housing and the coil spring. Thereby, the first spring can be deflected in a reliable and controlled manner. Furthermore, the deflection of the first spring can be limited, which means that the first spring does not contribute to the damping force characteristics in the second damping force region or the third damping force region.

[0031] According to one embodiment, the deflection distance between the inner shim spring portion and the innermost shim spring portion is created by the second spring being biased between the second fixation member in the valve housing and the coupling member. In particular, the coupling member can be coupled with the innermost shim spring portion via the previously mentioned protrusion when the coupling member is a spring cap. The deflection distance between the inner shim spring portion and the innermost shim spring portion can be determined by how much the protrusion protrudes from the body of the spring cap. This provides a reliable way of ensuring that the deflection distance of the second spring is indeed limited and does not affect the damping force characteristics in the third damping force region.

[0032] According to one embodiment, the legs connecting the innermost shim spring portion to the inner shim spring portion extend in a radial direction from the center of the shim spring. The legs can be placed symmetrically between the inner shim spring portion and the innermost shim spring portion. The thickness, width and length can be formed accordingly in order to achieve the desired spring constant.

[0033] According to one embodiment, the legs connecting the inner shim spring portion and the outer shim spring portion extend in a circumferential direction of the shim spring. The legs can be placed symmetrically between the outer shim spring portion and the inner shim spring portion. The thickness, width and length can be formed accordingly in order to achieve the desired spring constant.

[0034] According to one embodiment, one or both of the first stroke length and the second stroke length is less than 2 mm, preferably less than 1 mm. By having a smaller stroke length, the valve arrangement can be manufactured in a more compact form factor.

[0035] According to one embodiment, the valve arrangement can be adapted to be arranged in a shock absorber comprising a pilot valve. The pilot valve can comprise one or more pilot valve members adapted to be axially displaceable relative to a pilot valve seat. The one or more pilot valve members can be adapted to be axially displaceable by a solenoid device configured to be able to generate a solenoid force acting on the one or more pilot valve members. The solenoid device can comprise an actuation member adapted to be movable in an axial direction to or from the one or more pilot valve members under influence of the solenoid device. The solenoid force is then generated by the solenoid device, forcing the actuation member to move towards and interact with the one or more pilot valve members. The pilot valve can comprise a pilot valve spring arranged to counteract the solenoid force acting on the pilot valve member. The pilot valve spring can be arranged to interact with the one or more pilot valve members in a direction counteracting the solenoid force. The pilot valve spring can constitute part of the one or more pilot valve members. The pilot valve spring can be a shim spring adapted to be movable between a first position interacting with the pilot valve seat and a second position positioned away from the pilot valve seat. The actuation member can be adapted to interact with the shim spring such that the shim spring is flexed into the first position. When the shim spring is in the second position, the actuation member can be in a position not interacting with the shim spring, or in a position in contact with the shim spring but not causing the shim spring to flex further. The shim spring can differently regulate a flow of damping medium when in the first and second positions. The solenoid force can be adjustable by adjusting the solenoid device.

[0036] The pilot valve can be adapted for fail-safe operation, i.e. a safety mode of operation when the solenoid force can inadvertently disappear. The pilot valve spring can push the pilot valve member to a position where the damping fluid can flow through the pilot valve member. In case the pilot valve spring forms part of the one or more pilot valve members, the shim spring can move to a less flexed position. The pilot valve can define a first damping medium flow path and a second medium flow path. When the solenoid device is operating normally, the pilot valve can regulate the damping medium flow along the first damping medium flow path. In particular, the damping medium flow can be regulated along the first damping medium flow path by the shim spring. Further, the size of the solenoid force can be related to how much the damping medium flow is regulated. During fail-safe operation, i.e. when the solenoid force is not present or insufficient to counteract the pilot valve spring, the first damping medium flow path can be closed, such that most or all of the damping medium flows along the second damping medium flow path. The pilot valve can be adapted to regulate the damping medium flow along the second damping medium flow path during fail-safe operation. The pilot valve can be adapted to do so by a fail-safe shim. Under fail-safe operation, the fail-safe shim can be in a biased state. In case the pilot valve spring forms part of the one or more pilot valve members and is the shim spring, the first damping medium flow path can be closed during fail-safe operation by the shim spring. The first damping fluid flow path can be defined in part by one or more channels extending through the pilot valve body.

[0037] The pilot valve spring can be a shim spring, such as a coil spring. According to a preferred embodiment, the pilot valve spring can be a shim spring. The pilot valve spring can be adapted to provide different spring forces by deflecting different spring portions depending on the position of the pilot valve member. The different spring portions can be adapted to abut an inner portion of the pilot valve. According to one embodiment, the pilot valve spring defines a first shim spring and a second shim spring connected to each other. The first shim spring can be defined by a first shim spring portion corresponding to an outer rim of the shim spring, and a second shim spring portion corresponding to an inner portion, which is connected to the first shim spring portion via a flexible branch. The second shim spring can be defined by a second shim spring portion corresponding to the inner portion, and a third shim spring portion corresponding to an innermost shim spring portion, which is connected to the inner portion via a flexible branch. The flexible branch connecting the first shim spring portion and the second shim spring portion can be two, three, four, five or more. The flexible branch connecting the second shim spring portion and the third shim spring portion can be two, three, four, five or more. The first shim spring can be characterized by a different spring constant than the second shim spring. The first shim spring can be characterized by a spring constant that is greater than the spring constant of the second shim spring. The first shim spring can be characterized by a spring constant that is smaller than the spring constant of the second shim spring. The flexible branch connecting the first shim spring portion and the second shim spring portion can extend in a circumferential direction. "Extending in a circumferential direction" can mean that the flexible branch extends a distance from one point of the first shim spring portion to one point of the second shim spring portion, which is offset in a circumferential direction relative to said one point of the first shim spring portion and a center point of the shim spring. The circumferential offset can be between 10-90 degrees. The flexible branch connecting the second shim spring portion and the third shim spring portion can also extend in a circumferential direction. The circumferential offset between the corresponding points can be between 10-90 degrees.

[0038] According to one embodiment, the valve arrangement is adapted to operate under influence of a pilot valve controlled by a solenoid device. The solenoid device can be controlled to adjust a pressure influencing operation of the valve arrangement. The solenoid device can adjust the pilot valve. The valve arrangement can be in fluid connection with the pilot valve. A damping medium flow can flow via the valve arrangement into the pilot valve. The pilot valve can be adapted to provide a first damping medium flow path and a second damping medium flow path. During normal operation, the damping medium flow can be adjusted by the pilot valve along the first damping medium flow path. During a failsafe operation, i.e. when the solenoid device no longer provides a solenoid force or at least a solenoid force of sufficient size, the pilot valve can adjust the damping medium flow along the second damping medium flow path. The first damping medium flow path and the second damping medium flow path can constitute parallel damping medium flow paths.

[0039] According to a second aspect of the present invention, a shock absorber is provided. The shock absorber comprises a valve arrangement according to the first aspect of the present invention or any one of the embodiments thereof. By having the valve arrangement in the shock absorber, the shock absorber can thus be operated in a desired manner. For example, the shock absorber can be characterized by the previously mentioned desired damping force characteristics.

[0040] According to a third aspect of the present invention, a method for controlling a flow of damping medium between damping chambers of a shock absorber is provided. This is done by a valve arrangement comprising a valve member being axially movable relative to a housing, by which movement an opening defined by an interface between the valve member and a valve seat is adjusted, and a spring arrangement comprising a first spring, a second spring and a helical spring arranged between the valve member and a coupling member coupled to the first spring and the second spring, wherein the flow of damping medium between the damping chambers of the shock absorber is regulated by a force balance of the valve member, which force balance is partly or mainly generated by a damping medium pressure acting on the valve member in dependence of the flow of damping medium and in opposition to an action of the spring arrangement. The method comprises the steps of adjusting said force balance by deflecting the first spring when the valve member is moved not more than a first stroke length relative to a predetermined reference position, adjusting said force balance by deflecting the second spring when the valve member is moved more than the first stroke length, and adjusting said force balance by compressing the helical spring when the valve member is moved more than a second stroke length greater than the first stroke length.

[0041] The present invention is defined by the appended independent claims, embodiments are set forth in the appended dependent claims, in the following description and in the attached drawings. BRIEF DESCRIPTION OF DRAWINGS

[0042] The present invention will be described in more detail in the following, with reference to the appended drawings, in which:

[0043] Figure 1 A valve arrangement according to one embodiment of the present invention is shown assembled to a solenoid for a shock absorber;

[0044] Figure 2 An exploded perspective view of a valve arrangement according to one embodiment of the present invention is shown;

[0045] Figure 3 An exploded side view of a valve arrangement according to one embodiment of the present invention is shown;

[0046] Figures 4a to 4d A cross-sectional view of a valve arrangement according to one embodiment of the present invention is shown;

[0047] Figure 5 A spring of a spring arrangement according to one embodiment of the present invention is shown;

[0048] Figure 6 A damping force characteristic achieved by a valve arrangement according to one embodiment of the application is shown;

[0049] Figure 7 A spring according to one embodiment of the application is shown;

[0050] Figure 8a and Figure 8b A sectional view of a valve arrangement and a pilot valve with fail-safe operation according to one embodiment of the application is shown;

[0051] Figure 9a and Figure 9b Each shows a shock absorber according to one embodiment of the application, and

[0052] Figure 10 A flow chart of a method according to one embodiment of the application is shown. DETAILED DESCRIPTION

[0053] The present application will be described hereinafter more fully with reference to the accompanying drawings, in which preferred embodiments of the application are shown. The application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art. In the drawings, like numbers refer to like elements throughout.

[0054] Figure 1 A valve arrangement 1 according to one embodiment of the application is shown. The valve arrangement 1 is adapted to be arranged in or to a shock absorber 200a, 200b and to regulate the flow of damping medium between damping chambers (commonly referred to as compression and rebound chambers) of the shock absorber. However, in Figure 1 for a more concentrated presentation of the valve arrangement 1, all parts of the shock absorber 200a, 200b except the solenoid 100 are omitted from the illustration. See Figure 9a , Figure 9b different types of shock absorbers 200a, 200b incorporating the valve arrangement 1 and the solenoid 100 are demonstrated.

[0055] As shown in Figure 1 , the valve arrangement 1 comprises a valve member 3 which is axially movable relative to a housing 4. The housing 4 is provided with a generally cylindrical shape into which the valve member 3 is inserted via an opening towards the bottom, as can be seen in Figure 1 . The valve member 3 is adapted to be axially moved in the housing 4 away from a valve seat 2 on which the valve member 3 rests when in a rest stroke position X0' (see Figure 4a). When the valve member 3 is axially moved relative to the housing 4, an opening defined by the interface between the valve member 3 and the valve seat 2 is adjusted. This opening is closed when the valve member 3 rests on the valve seat 2, but is opened when the valve member 3 is axially displaced from the valve seat, thus allowing a flow of damping medium to flow through the opening. When the valve member 3 is moved even further away from the valve seat 2, the opening between the two is increased, which thus allows an even greater flow of damping medium. The valve member 3 is thus adapted to be movable relative to the housing 4 in response to a flow of damping medium Q flowing through the valve seat 2 towards the valve member 3. The axial displacement, i.e. the stroke length, of the valve member 3 is measured relative to a fixed and predetermined reference position X0 of the housing 4 (see e.g. Figure 4a ).

[0056] Further, as can be seen in Figure 1 , the valve member 3 is provided with a through hole, the size and form of which is adapted to allow a certain flow of damping medium to pass through the through hole. If the flow of damping medium is greater than the size of the through hole of the valve member is provided for, a pressure build-up occurs, acting on the valve member 3, causing the valve member to be further displaced in the axial direction from the valve seat 2 into the housing 4. This allows the damping fluid flow to be adjusted by the valve device 1.

[0057] The valve device 1 further comprises a spring device. The spring device comprises a first spring 6a, a second spring 6b and a coil spring 5. This “triple spring device” is adapted to resist the axial movement of the valve member 3, biasing the valve member to return into a rest stroke position towards the valve seat 2. In the embodiment shown in Figure 1 , the first spring 6a and the second spring 6b are provided by deflectable pad spring portions of a single pad spring 6. The coil spring 5 is arranged between the valve member 3 and a coupling member 7. In Figure 1 , the coupling member 7 is a spring cap adapted to be coupled to the end of the coil spring 5. The spring cap 7 is latched in the valve member 3 in a sliding manner, such that the coil spring 5 is securely held in place. The latching mechanism is provided by a set of latches arranged on respective flexible branches, which branches are flexible such that the branches flex towards each other, thus allowing the spring cap 7 to be partially inserted into the valve member 3. When inserted, the branches flex away from each other, which thus places the latches in place, preventing the spring cap from being detached from the valve member 3.

[0058] In one embodiment, the coil spring 5 is biased when the valve member 3 is in the rest stroke position X0'. How much the coil spring 5 is biased depends on the length of the coil spring 5, the depth of the valve member 3 cavity in which the coil spring 5 is placed, and the length of the branches of the spring cap 7. These parameters can be varied accordingly to achieve certain damping force characteristics.

[0059] According to some embodiments, in Figure 2 and Figure 3Each of the components of the valve arrangement 1 can be seen in the figure. As can be seen here, the spring cap 7 is arranged such that it is in contact with the washer spring 6. Further, the spring cap 7 is provided with a protrusion 71 extending in axial direction. The purpose of this protrusion is to engage with the innermost washer spring portion 62 of the washer spring 6. The first spring 6a and the second spring 6b are coupled to each other, and the protrusion 71 of the spring cap 7 enables a smaller interaction area, which facilitates the washer spring 6 to deform as intended.

[0060] According to one embodiment, it is desired that the first spring 6a is in a biased state when the valve member 3 is in the rest stroke position X0'. The bias of the first spring 6a is adjusted to press on the washer spring 6 such that with increasing stroke length, the first spring 6a is deflected first and then the second spring 6b is deflected. The valve arrangement 1 allows for the insertion of one or more adjustment washers 8 between the valve seat 2 and the housing 4. This allows for adjusting the offset distance between the valve seat 2 and the housing 4, and thus the rest stroke position of the valve member 3.

[0061] Figure 4a A cross-sectional view is shown when the valve seat 2 is arranged in the housing 4, showing the case represented by the gap between the adjustment washer 8 and the fixed portion 43 of the housing 4. When properly assembled, there is no gap between the valve seat 2 and the housing 4, or any gap between the valve seat 2, the housing 4, and any adjustment washers placed in between. Further, by inserting adjustment washers 8 of a preferred thickness, the relative position of the valve seat 2 with respect to the housing 4 can be adjusted. This thus adjusts the rest stroke position X0' of the valve member 3 in the housing 4. If no adjustment washers 8 are inserted, the valve seat 2 and the housing 4 can abut each other, which thus further positions the rest stroke position of the valve member 3 on the housing 4. Assuming that the dimensions of the valve member 3 and the spring arrangement are not changed, the further the rest stroke position of the valve member 3 is positioned in the housing 4, the more the first spring 6a is biased. Vice versa, the thicker the adjustment washers are, or the more adjustment washers are included, the further the rest stroke position of the valve member 3 is positioned in the outward direction of the housing 4. This thus reduces the extent to which the first spring 6b is biased when the valve member 3 is in the rest stroke position. Thus, it can be the case that the first spring is not biased at all when the valve member 3 is in the rest stroke position.

[0062] From Figure 4a It can be understood that in the shown embodiment, the first spring 6b is biased when the valve member 3 is in the rest stroke position - which can be understood as the washer spring 6 being in a fully undeflected state, but the valve seat 2 not yet fully inserted into the housing 4.

[0063] When arranged in a shock absorber, the damping medium flow between the damping chambers of the shock absorber is regulated by a force balance of the valve member 3. The force balance is partially or mainly generated by the damping medium, which acts on the valve member 3 depending on the damping medium flow and counteracts the action of the spring arrangement. Thus, when the damping medium acts on the valve member 3 and cannot flow through the valve member bore to the necessary extent, the pressure increases and the valve member 3 is forced away from the valve seat 2. In response to this movement, the first spring 6a deflects, so that the deflectable spring portion of the shim spring moves towards the fixed portion 42 of the housing 4. Since the coil spring is biased by the spring cap 7, this coil spring does not compress further until the first and second springs have first deflected. When the stroke length XI (as measured from a predetermined reference position X0 of the housing 4) is reached, the deflectable spring portion abuts the fixed portion 42, which prevents the first spring 6a from deflecting more. This is shown in Figure 4b .

[0064] When the valve member 3 moves beyond the stroke length XI, the second spring 6b begins to deflect. How much the second spring 6b can deflect depends on how far the protrusion of the spring cap 7 protrudes from the body of the spring cap 7. Once the body of the spring cap 7 abuts the shim spring 6, the second spring 6b is prevented from deflecting further, as shown in Figure 4c . Once this happens (at the second stroke length X2), the coil spring 5 will begin to compress to the maximum stroke length X3, in which case the valve member 3 abuts the outer edge of the shim spring, as shown in Figure 4d .

[0065] Figure 5 The shim spring 6 is shown in more detail, and the coil spring 5 is shown. The shim spring 6 is shaped in size and form to provide the first spring 6a and the second spring 6b. The first spring 6a is provided by an outer shim spring portion 60 forming an outer edge of the shim spring 6, and an inner shim spring portion 61 separate from the outer shim spring portion 60 and connected to the outer shim spring portion via a flexible branch 63, so that the outer shim spring portion 60 and the inner shim spring portion 61 can deflect relative to one another. The outer shim spring portion 60 and the inner shim spring portion 61 can deflect relative to one another by a first deflection distance corresponding to the first stroke length XI. The second spring 6b is provided by the inner shim spring portion 61, and an innermost shim spring portion 62 separate from the inner shim spring portion 61 but connected to the inner shim spring portion via a flexible branch 64, so that the inner shim spring portion 61 and the innermost shim spring portion 62 can deflect relative to one another. The inner shim spring portion 61 and the innermost shim spring portion 62 can deflect relative to one another by a second deflection distance corresponding to the second stroke length X2.

[0066] Further, in Figure 5In the middle, the flexible branches 64 connecting the innermost washer spring portion 62 to the inner washer spring portion 61 are shown as extending in a radial direction from the center of the washer spring 6. However, the flexible branches 64 can instead extend in a circumferential manner. The flexible branches 64 are five in total, and are arranged symmetrically between the innermost washer spring portion 62 and the inner washer spring portion 61. The flexible branches 63 connecting the inner washer spring portion 61 to the outer washer spring portion 60 extend in a circumferential direction of the washer spring 6. The flexible branches 63 are two in total, and are placed symmetrically between the inner washer spring portion 61 and the outer washer spring portion 60.

[0067] The damping force characteristic obtained by the present invention is shown in Figure 6 In the middle, the flexible branches 64 connecting the innermost washer spring portion 62 to the inner washer spring portion 61 are shown as extending in a radial direction from the center of the washer spring 6. However, the flexible branches 64 can instead extend in a circumferential manner. The flexible branches 64 are five in total, and are arranged symmetrically between the innermost washer spring portion 62 and the inner washer spring portion 61. The flexible branches 63 connecting the inner washer spring portion 61 to the outer washer spring portion 60 extend in a circumferential direction of the washer spring 6. The flexible branches 63 are two in total, and are placed symmetrically between the inner washer spring portion 61 and the outer washer spring portion 60.

[0068] Figure 1 Also depicted is a pilot valve 12 fluidly connected to the valve device 1. The pilot valve 12 comprises a washer spring 9, a pilot valve seat 14 and a pilot valve body 11. In Figure 1In the embodiment shown in the figures, the pilot valve seat 14 is formed as an integral part of the valve housing 4. Alternatively, the pilot valve seat can be formed as a separate part from the valve housing, but fixedly attached to the valve housing. The shim spring 9 comprises an outer shim spring portion and an innermost shim spring portion, which is connected to the outer shim spring portion via a flexible branch, either directly or via an intermediate inner shim spring portion, which is connected to the outer shim spring portion via a flexible branch. Thereby, the shim spring 9 is adapted to move partially between a first position, where the innermost shim spring portion interacts with the valve seat 14 to adjust the flow of damping medium through the pilot valve seat 14, and a second position, remote from the pilot valve seat 14. The outer shim spring portion of the shim spring 9 is essentially fixed with respect to, but offset from, the pilot valve seat 14. Thus, the innermost shim spring portion is biased to move in a direction towards the second position, either when interacting with the valve seat 14 in the first position, or when displaced from the second position at least. The position of the innermost shim spring portion is controlled by the solenoid device 100, which is configured to generate a solenoid force acting on the innermost shim spring portion via the actuation member 13, which is axially displaceable with respect to the pilot valve body 11 to interact with the innermost shim spring portion. Further, the pilot valve body 11 is shaped in size and form to define a cavity extending in the axial direction, in which the actuation member 13 is movable.

[0069] The pilot valve body 11 further defines one or more pilot valve body channels extending from an opening facing the pilot valve seat 14 and to a respective auxiliary opening leading out to the surroundings of the pilot valve body 11. In the embodiment shown in the figures, two such auxiliary openings are shown. Figure 1 The one or more pilot valve body channels are further at least partially defined by a gap between the actuation member 13 and the pilot valve body 11. As shown in Figure 1 The actuation member 13 is narrower than the through hole of the pilot valve body 11, resulting in said gap, as shown in

[0070] The shim spring 9 can have a shape as illustrated in Figure 7 Figure 7 ​The pilot shim spring 9 shown in

[0071] The pilot shim spring 9 can also be adapted in shape and size to provide one or more openings 95 near the outer diameter of the shim spring, as shown in Figure 7 Figure 7 The one or more openings can be three, as shown in Figure 8a The one or more openings 95 are able to put the pilot valve body 11 in fluid communication with the valve housing 4 through the pilot valve seat, as shown in

[0072] The damping medium flow can flow through these one or more openings via the main port in the pilot valve seat and / or the auxiliary valve port in the pilot valve seat. Figure 8a Figure 8b These and also the fail-safe operation are shown in more detail.

[0073] In Figure 8a , the pilot valve operates normally, which means that the solenoid force F s ​​acting on the shim spring 9, causes the innermost shim spring portion 92 to be pushed towards the valve seat 14. Thus, the damping medium flow is regulated at the interface 15 between the valve seat 14 and the innermost shim spring portion 92. A first damping medium flow path continues from this regulating interface 15 into a pilot valve body channel formed in the pilot valve body 11, along a gap between the actuating member 13 and the inner face of the pilot valve body 11, and then through a secondary opening to the surroundings of the pilot valve body 11. This first damping medium flow path is indicated by the arrow in Figure 8a When the shim spring 9 is in this state, it is biased to return to a position of less flexure, which means that the solenoid force F s acting on the shim spring 9, the shim spring will move away from the pilot valve seat 14.

[0074] However, when the solenoid device 100 intentionally or unintentionally stops generating the solenoid force F s acting on the innermost shim spring portion 92, the innermost shim spring portion 92 will move away from the valve seat 14 into a second position, in which it blocks the first damping medium flow path Q1 by covering the pilot valve body channel opening in the pilot valve body 11. In this state, the damping medium flow is forced to flow along a second damping medium flow path Q2, as shown in Figure 8b , in which the fail-safe shim regulates the damping medium flow. In particular, the regulation takes place at an interface 16 formed between the fail-safe shim and the shim spring 9.

[0075] Hereby, the pilot valve 12 can provide damping medium flow regulation even if the solenoid device stops generating the solenoid force F s .

[0076] Figure 9a 、 Figure 9b A shock absorber according to different embodiments of the present application is shown. Figure 9a A shock absorber 200a of a three-cylinder design is shown, which comprises a valve arrangement 1 and a solenoid device 100. In this design, the valve arrangement 1 regulates the damping medium flow in both the rebound stroke and the compression stroke. Figure 9b A shock absorber 200b of a two-cylinder design is shown, which comprises a first valve arrangement and a second valve arrangement 1, and corresponding solenoid devices 100. In this design, one of the two valve arrangements regulates the damping medium flow during the rebound stroke, while the other of the two valve arrangements regulates the damping medium flow during the compression stroke.

[0077] Figure 10A flow chart illustrating a method according to an embodiment of the present application is shown. The method S0 relates to a method for controlling the flow of damping medium between damping chambers of a shock absorber by means of a valve arrangement 1. The valve arrangement 1 comprises a valve member 3 which is axially movable relative to a housing 4, by which movement an opening defined by the interface between the valve member 3 and a valve seat 2 is adjusted. The valve arrangement 1 used by the method comprises a spring arrangement comprising a first spring 6a, a second spring 6b and a coil spring 5 arranged between the valve member 3 and a coupling member 7 coupled to the first spring 6a and the second spring 6b. The flow of damping medium between damping chambers of a shock absorber is regulated by a force balance of the valve member 3, which force balance is partly or mainly generated by a damping medium pressure acting on the valve member 3 in opposition to the action of the spring arrangement, which depends on the flow of damping medium. The method comprises the steps of adjusting S1 said force balance by deflecting the first spring 6a when the valve member 3 is moved not more than a first stroke length X1 relative to a predetermined reference position X0, adjusting S2 said force balance by deflecting the second spring 6b when the valve member 3 is moved more than the first stroke length X1, and adjusting S3 said force balance by compressing the coil spring 5 when the valve member 3 is moved more than a second stroke length X2 which is greater than the first stroke length X1.

[0078] In the drawings and specification, there have been disclosed preferred embodiments and examples of the application, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the application being set forth in the following claims.

Claims

1. A valve arrangement (1) for a shock absorber, the valve arrangement comprising: a valve member (3) axially movable relative to a housing (4), by moving an opening defined by an interface between the valve member (3) and a valve seat (2) is adjusted, a spring arrangement comprising a first spring (6a), a second spring (6b) and a coil spring (5) arranged between the valve member (3) and a coupling member (7) coupled to the first spring (6a) and the second spring (6b), wherein the valve arrangement (1) is adapted such that, when arranged in a shock absorber, a damping medium flow between damping chambers of the shock absorber is adjusted by a force balance of the valve member (3), the force balance being partly or mainly generated by a damping medium pressure depending on the damping medium flow and acting on the valve member (3) counter to an action of the spring arrangement (5, 6a, 6b, 7), and when the valve member (3) is moved not more than a first stroke length (XI) relative to a predetermined reference position (X0), the first spring (6a) deflects to adjust said force balance, when the valve member (3) is moved more than the first stroke length (XI), the second spring (6b) deflects to adjust said force balance, and when the valve member (3) is moved more than a second stroke length (X2) greater than the first stroke length (XI), the coil spring (5) compresses to adjust said force balance, wherein the second spring (6b) has a higher spring constant than the first spring (6a) and the coil spring (5).

2. Valve device (1) according to claim 1, wherein When the valve member (3) is in a predetermined rest stroke position (X0') relative to the predetermined reference position (X0), the coil spring (5) is biased.

3. Valve device (1) according to any one of claims 1 to 2, wherein The coupling member (7) is a spring cap adapted with a latch (72) for maintaining the bias of the coil spring while allowing the coil spring (5) to be compressed in a controlled manner.

4. Valve device (1) according to claim 2, wherein The predetermined rest stroke position (X0') is adjustable by inserting an adjustment shim (8) having a thickness between the valve seat (2) and the housing (4).

5. Valve device (1) according to claim 2, wherein Both the first spring (6a) and the second spring (6b) are provided by deflectable shim spring portions (60, 61, 62) of a single shim spring (6).

6. Valve device (1) according to claim 5, wherein The first spring (6a) is provided by an outer washer spring portion (60) forming an outer rim of the washer spring (6), and an inner washer spring portion (61) separate from the outer washer spring portion (60) and connected to the outer washer spring portion via a flexible branch (63), such that the outer washer spring portion (60) and the inner washer spring portion (61) are deflectable relative to each other by a first deflection distance corresponding to the first stroke length (X1), and wherein the second spring (6b) is provided by the inner washer spring portion (61), and an innermost washer spring portion (62) separate from the inner washer spring portion (61) but connected to the inner washer spring portion via a flexible branch (64), such that the inner washer spring portion (61) and the innermost washer spring portion (62) are deflectable relative to each other by a second deflection distance corresponding to the second stroke length (X2).

7. Valve device (1) according to claim 6, wherein The coupling member (7) is a spring cap comprising a protrusion (71) adapted to press onto the innermost washer spring portion (62).

8. Valve device (1) according to any one of claims 6 to 7, wherein The deflection distance between the outer washer spring portion (60) and the inner washer spring portion (61) is biased by the first spring (6a) between a first fixed part (41) in the housing (4) and the coupling member (7).

9. Valve device (1) according to any one of claims 6 to 7, wherein, The deflection distance between the inner washer spring portion (61) and the innermost washer spring portion (62) is biased by the second spring (6b) between a second fixed part (42) in the housing (4) and the coil spring (5).

10. Valve device (1) according to any one of claims 6 to 7, wherein The branch (64) connecting the innermost washer spring portion (62) to the inner washer spring portion (61) extends in a direction from a center of the washer spring (6).

11. Valve device (1) according to any one of claims 6 to 7, wherein The branch (63) connecting the inner washer spring portion (61) and the outer washer spring portion (60) extends in a circumferential direction of the washer spring (6).

12. Valve arrangement (1) according to any one of claims 1 to 2, 4 to 7, adapted to be operated under influence of a pilot valve (12) controlled by a solenoid device.

13. Shock absorber comprising a valve arrangement (1) according to any one of the preceding claims.

14. A method for controlling the flow of damping medium between damping chambers of a shock absorber by means of a valve arrangement, which valve arrangement comprises: a valve member (3) axially movable relative to a housing (4), by movement an opening defined by an interface between the valve member (3) and a valve seat (2) is adjusted; and a spring arrangement comprising a first spring (6a), a second spring (6b) and a coil spring (5) arranged between the valve member (3) and a coupling member (7) coupled to the first spring (6a) and the second spring (6b), wherein a damping medium flow between damping chambers of the shock absorber is regulated by a force balance of the valve member (3), the force balance being partially or predominantly generated by a damping medium pressure depending on the damping medium flow and acting on the valve member (3) counter to an action of the spring arrangement (5, 6a, 6b, 7), The method comprises the steps of: when the valve member (3) is moved by not more than a first stroke length (X1) relative to a predetermined reference position (X0), the force balance is adjusted by deflecting the first spring (6a), when the valve member (3) is moved by more than the first stroke length (X1), the force balance is adjusted by deflecting the second spring (6b), and when the valve member (3) is moved by more than a second stroke length (X2) which is greater than the first stroke length (X1), the force balance is adjusted by compressing the coil spring (5), wherein the second spring (6b) has a higher spring constant than the first spring (6a) and the coil spring (5).

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