Noise-reduced valve arrangement

Abstract

Shock absorbers (20, 26) comprising: a pressure tube (30) that defines a fluid chamber; a piston arrangement (32) arranged within the pressure tube (30), wherein the piston arrangement (32) divides the fluid chamber into an upper working chamber (44) and a lower working chamber (46); a first valve arrangement which engages with the piston arrangement (32), wherein the first valve arrangement comprises a first circular valve body (60) and a first valve disk (80) which engages with the first circular valve body (60); wherein the first circular valve body (60) defines a first circular outer valve web (110) and a first non-circular inner valve web (112), wherein the first valve disk (80) engages with an entire upper surface of the first non-circular inner and first circular outer valve webs (112, 110), and wherein a center of the first circular outer valve web (110) is positioned in a center of the first circular valve body (60), characterized in that the first non-circular inner valve web (112) is a non-circular web with a circular section (AB) having its center in the center of the first circular valve body (60), a circular section (CD) having its center at a point spaced apart from the center of the first circular valve body (60), and with transition sections (BC; DA) between the circular sections (AB; CD); wherein the first circular valve body (60) defines a plurality of compression passages (70) and a plurality of expansion passages (72); and wherein the plurality of compression passages (70) is arranged only in a section of the area between the first circular outer valve web (110) and the first non-circular inner valve web (112), which corresponds to a position in the circumferential direction where the width between the first circular outer valve web (110) and the first non-circular inner valve web (112) is greater than the minimum width between the first circular outer valve web (110) and the first non-circular inner valve web (112).

Description

Area:

[0001] The present disclosure relates generally to hydraulic dampers or shock absorbers for use in a suspension system, such as a suspension system for motor vehicles. In particular, the present disclosure relates to a valve arrangement having an eccentric pressure area on a valve disk to control the opening of the valve arrangement. background

[0002] Shock absorbers are used in conjunction with vehicle suspension systems to absorb unwanted vibrations that occur while driving. To absorb these unwanted vibrations, the shock absorbers are generally connected between the sprung section (vehicle body) and the unsprung section (suspension) of the vehicle. A piston is located inside a pressure tube of the shock absorber, and the pressure tube is connected to the unsprung section of the vehicle. The piston is connected to the sprung section of the vehicle via a piston rod that extends through the pressure tube. The piston divides the pressure tube into an upper working chamber and a lower working chamber, each filled with hydraulic fluid.Because the piston, via a valve control, is able to restrict the flow of hydraulic fluid between the upper and lower working chambers when the shock absorber is compressed or extended, the shock absorber can generate a damping force that counteracts the vibrations that would otherwise be transmitted from the unsprung to the sprung section of the vehicle. In a twin-tube shock absorber, a fluid reservoir or compensating chamber is located between the pressure tube and the compensating tube. A bottom valve assembly is positioned between the lower working chamber and the compensating chamber to also generate a damping force that counteracts the vibrations that would be transmitted from the unsprung to the sprung section of the vehicle.

[0003] As described above for a twin-tube shock absorber, the valve control at the piston restricts the flow of damping fluid between the upper and lower working chambers when the shock absorber is extended to produce a damping force. The valve control at the bottom valve restricts the flow of damping fluid in the lower working chamber and the equalizer chamber when the shock absorber is compressed to produce a damping force. In a monotube shock absorber, the valve control at the piston restricts the flow of damping fluid between the upper and lower working chambers when the shock absorber is extended or compressed to produce a damping force. During driving, the suspension system compresses and extends.During compression, the shock absorber is compressed, forcing the damping fluid through the base valve in a twin-tube shock absorber or through a piston valve on the piston in a monotube shock absorber. A damping valve located at the base valve or on the piston controls the flow of damping fluid and thus the damping force generated. During rebound, the shock absorber extends, forcing the damping fluid through the piston in both twin-tube and monotube shock absorbers. A damping valve located on the piston controls the flow of damping fluid and thus the damping force generated.

[0004] In a twin-tube shock absorber, the piston and bottom valve typically comprise a multitude of compression passages and a multitude of expansion passages. During compression, the damping valve at the bottom valve opens the compression passages in the bottom valve to control fluid flow and generate a damping force. A fluid valve at the piston opens the compression passages in the piston to replace damping fluid in the upper working chamber; however, this check valve contributes little or nothing to the overall damping force. The damping valve at the piston closes the expansion passages of the bottom valve during compression or rebound.During rebound in a twin-tube shock absorber, the damping valve at the piston opens the expansion ports in the piston to control the fluid flow and generate a damping force. The fluid valve at the bottom valve opens the expansion ports in the bottom valve to replace damping fluid in the lower working chamber; however, this fluid valve contributes little or nothing to the overall damping force.

[0005] In a monotube shock absorber, the piston typically comprises multiple compression passages and multiple expansion passages. The shock absorber further includes means for compensating for the fluid flow through the rod volume, as is well known in the prior art. During compression, in a monotube shock absorber, the compression damping valve opens the compression passages in the piston to control the fluid flow and generate a damping force. The expansion damping valve closes the expansion passages of the piston during rebound. During rebound, in a monotube shock absorber, the expansion damping valve opens the expansion passages in the piston to control the fluid flow and generate a damping force.The compression damping valve on the piston closes the compression passages of the piston during a rebound movement.

[0006] For most shock absorbers, the damping valves are designed as a standard open / close valve, although some valves may include a drain for damping fluid. Due to this open / close design, pressure fluctuations can occur. These pressure fluctuations can result in high-frequency vibrations generated by the shock absorber, which can be an undesirable nuisance.

[0007] Prior art according to the preamble of claim 1 is disclosed in document DE 689 10 365 T2. Further prior art in the present technical field is known from documents DE 10 2011 004 739 A1, DE 10 2010 060 792 A1, DE 11 2004 001 829 B4, JP 2010-107 003 A, DE 11 2006 002 168 T5 and JP H10-196 703 A. Summary

[0008] This section provides a general summary of the revelation and is not to be understood as a comprehensive revelation of the entire realm or of its characteristics.

[0009] A valve assembly for a shock absorber comprises a valve disc that bears against inner and outer sealing ribs formed on a valve body. In the region between the inner and outer sealing ribs, fluid pressure acts against the valve disc to move the sealing disc away from the sealing ribs. The distance between the inner and outer sealing ribs varies radially depending on a position in the circumferential direction between the inner and outer sealing ribs. This controls the initial opening of the valve assembly. Then, as the fluid pressure increases, an additional circumferential region of the valve disc opens until the entire circumferential region of the valve disc is open. The object of the invention is to provide a noise-reduced valve assembly for a shock absorber. This object is achieved by the combination of features according to claim 1.

[0010] Further areas of application will become clear from the description provided here. The description and specific examples in this summary serve only as illustrations and not to limit the scope of protection of this disclosure. Drawings

[0011] The drawings described here serve only the purpose of describing selected embodiments and not all possible implementations; they also do not serve to limit the scope of protection of the present disclosure. Fig. Figure 1 is a representation of an automobile with shock absorbers incorporating the valve formation according to the present disclosure; Fig. Figure 2 is a side view, partially in cross-section, of a twin-tube shock absorber made of Fig. 1, which includes the valve design according to the present disclosure; Fig. Figure 3 is an enlarged side view, partially in cross-section, of a piston arrangement of the in Fig. 2 shock absorber shown; Fig. 4 is an enlarged side view, partially in cross-section, of a bottom valve arrangement of the in Fig. 2 shock absorbers shown; Fig. 5 is a top view of the piston body of the in Fig. 3 arrangement shown; Fig. 6 is a top view of the piston body, which is in Fig. 4 bottom valve arrangement shown; Fig. 7 is a top view of the valve disc, which is used both in the Fig. 3 piston arrangement as well as in the one shown in Fig. The bottom valve arrangement shown in section 4 is used.

[0012] The same reference symbols name the same parts in all views of the drawings. Detailed description

[0013] Exemplary embodiments are now described in more detail with reference to the attached drawings.

[0014] The following description is merely exemplary and is not intended to limit the present disclosure, application, or use. Fig. Figure 1 shows a vehicle with a suspension system including shock absorbers, each of which comprises a piston assembly according to the present invention, and which is generally designated by reference numeral 10. The vehicle 10 comprises a rear suspension 12, a front suspension 14, and a vehicle body 16. The rear suspension 12 has a transversely extending axle assembly (not shown) adapted to operatively support a pair of rear wheels 18. The rear axle is attached to the vehicle body by a pair of shock absorbers 20 and a pair of springs 22. Similarly, the front suspension 14 comprises a transversely extending front axle assembly (not shown) to operatively support a pair of front wheels 24. The front axle assembly is attached to the vehicle body 16 by a pair of shock absorbers 26 and a pair of springs 28.The shock absorbers 20 and 26 serve to dampen the relative movement of the unsprung section (i.e., front and rear suspensions 12, 14) with respect to the sprung section (i.e., the vehicle body 16) of the vehicle 10. Although the vehicle 10 is shown as an automobile with front and rear axle arrangements, the shock absorbers 20 and 26 can also be used in other vehicle types or applications, including, but not limited to, vehicles with non-independent rear suspensions, vehicles with independent front and / or independent rear suspensions, or other suspension systems known from the prior art. Furthermore, the term "shock absorber," as used here, is to be understood as encompassing dampers in general, and thus also McPherson struts and other damper designs known from the prior art.

[0015] Referring to Fig. Figure 2 shows the shock absorber 20 in more detail. Even if Fig. Figure 2 shows only the shock absorber 20; it is understood that the shock absorber 26 also includes the valve assembly described below for the shock absorber 20. The shock absorber 26 differs from the shock absorber 20 only in the way it is adapted to be attached to the sprung and unsprung mass of the vehicle 10. The shock absorber 20 comprises a pressure tube 30, a piston assembly 32, a piston rod 34, a compensating tube 36, and a bottom valve assembly 38.

[0016] The pressure tube 30 defines a working chamber 42. The piston assembly 32 is slidably arranged within the pressure tube 30 and divides the working chamber 42 into an upper working chamber 44 and a lower working chamber 46. A seal 48 is arranged between the piston assembly 32 and the pressure tube 30 to allow sliding movement of the piston assembly 32 relative to the pressure tube 30 without generating excessive frictional forces and to seal the upper working chamber 44 against the lower working chamber 46. The piston rod 34 is attached to the piston assembly 32 and extends through the upper working chamber 44 and through the upper end cap 50, which closes the upper end of the pressure tube 30. A sealing system seals the connection between the upper end cap 50, the compensating tube 36, and the piston rod 34.The end of the piston rod 34 opposite the piston assembly 32 is adapted to be attached to the sprung mass of the vehicle 10. The valve control within the piston assembly 32 controls the movement of the fluid between the upper working chamber 44 and the lower working chamber 46 during the movement of the piston assembly 32 within the pressure tube 30. Since the piston rod 34 extends only through the upper working chamber 44 and not through the lower working chamber 46, the movement of the piston assembly 32 with respect to the pressure tube 30 creates a difference in the amount of fluid displaced in the upper working chamber 44 compared to the amount of fluid displaced in the lower working chamber 46. This difference in the amount of fluid displaced is known as the "rod volume" flowing through the bottom valve assembly 38.

[0017] The compensating tube 36 surrounds the pressure tube 30 to define a fluid compensating chamber 52 located between the tubes 30 and 36. The lower end of the compensating tube 36 is closed by a bottom cap 54, which is adapted to be connected to the unsprung mass of the vehicle 10. The upper end of the compensating tube 36 is attached to the upper end cap 50. The bottom valve assembly 38 is located between the lower working chamber 46 and the compensating chamber 52 to control the fluid flow between the chambers 46 and 52. When the shock absorber 20 extends lengthwise, an additional volume of fluid is required in the lower working chamber 46 due to the "rod volume concept." Therefore, fluid will flow from the compensating chamber 52 to the lower working chamber 46 through the bottom valve assembly 38, as described below.When the shock absorber 20 is compressed lengthwise, excess fluid must be removed from the lower working chamber 46 due to the "rod volume concept". Therefore, fluid will flow from the lower working chamber 46 to the compensation chamber 42 through the bottom valve arrangement 38, as described below.

[0018] Referring to Fig. The piston assembly 32 comprises a first circular valve body 60, a compression valve assembly 62, and an expansion valve assembly 64. The compression valve assembly 62 is mounted on a shoulder 66 on the piston rod 34. The first circular valve body 60 is mounted on the compression valve assembly 62, and the expansion valve assembly 64 is mounted on the first circular valve body 60. A nut 68 secures the components to the piston rod 34.

[0019] The first circular valve body 60 defines a plurality of compression passages 70 and a plurality of expansion passages 72. The seal 48 comprises a plurality of ribs 74 that fit into a plurality of annular grooves 76 to allow sliding movement of the piston assembly 32.

[0020] The compression valve assembly 62 comprises a support disc 78, a valve disc 80, and a spacer disc 82. The support discs 78 bear against the shoulder 66 at one end and against the spacer disc 82 at the opposite end. The spacer disc 82 bears against the support disc 78 at one end and against the valve disc 80 at the other end. The valve disc bears against the spacer disc 82 at one end and against the first circular valve body 60 at the other end. The valve disc 80 bears against the first circular valve body 60 and closes the compression ports 70 while leaving the expansion ports 72 open. During compression, the fluid in the lower working chamber 46 is pressurized, causing fluid pressure to act against the valve disc 80.When the fluid pressure acting against the valve disc 80 exceeds the bending force of the valve disc 80, the valve disc 80 bends away from the first circular valve body 60 to open the compression passages 70 and allow fluid flow from the lower working chamber 46 to the upper working chamber 44. Normally, a low fluid pressure acting against the valve disc 80 causes the valve disc 80 to bend away, and the compression valve assembly 62 acts as a check valve between chambers 46 and 44, generating no or only partial damping forces. The damping characteristics of the shock absorber 20 during compression are typically controlled by the bottom valve assembly 38, which balances the fluid flow from the lower working chamber 46 to the compensation chamber 52 based on the "rod volume concept." During rebound, the compression passages 70 are closed by the valve disc 80.

[0021] The expansion valve assembly 64 comprises a spacer 84, a plurality of valve discs 86, a retainer 88, and a spring 90. The spacer 84 is threaded onto the piston rod 34 and positioned between the first circular valve body 60 and the nut 68. The spacer 84 holds the first circular valve body 60 and the compression valve assembly 62 while allowing the nut 68 to be tightened without compressing the valve discs 86. The support disc 78, the spacer disc 82, the valve disc 80, the first circular valve body 60, and the spacer 64 ensure a lasting, secure connection between the shoulder 66 and the nut 68, thus simplifying the tightening and securing of the nut 68 to the spacer 84 and, consequently, to the piston rod 34.The valve discs 86 are slidably mounted on the spacer 84 and bear against the first circular valve body 60 to close the expansion ports 72 while the compression ports 70 remain open. The holder 88 is also slidably mounted on the spacer 84 and abuts the valve discs 86. The spring 90 is mounted above the spacer 84 and positioned between the holder 88 and the nut 68, which is threaded onto the spacer 84. The spring 90 biases the holder 88 against the valve discs 86 and the valve discs 86 against the first circular valve body 60. When fluid pressure is applied to the valve discs 86, they will flex elastically at their outer circumferential edges to open the expansion valve assembly 64.A spacer washer 108 is arranged between the nut 68 and the spring 90 to control the preload for the spring 90 and thus the blow-off pressure, as described below. This allows the adjustment of the blow-off feature of the expansion valve assembly 64 to be separated from the adjustment of the compression valve assembly 62.

[0022] During rebound, fluid in the upper working chamber 44 is pressurized, causing the fluid pressure to act against the valve discs 86. When the fluid pressure acting against the valve discs 86 exceeds the bending force of the valve discs 86, the valve discs 86 flex elastically and open the expansion passages, allowing fluid to flow from the upper working chamber 44 to the lower working chamber 46. The stiffness of the valve discs 86 and the size of the expansion passages determine the damping characteristics for the expansion valve assembly 64. When the fluid pressure within the upper working chamber 44 reaches a predetermined level, it exceeds the preload force of the spring 90, causing axial movement of the holder 88 and the multiple valve discs 86.The axial movement of the holder 88 and valve discs 86 fully opens the expansion passages 72, allowing a significant amount of damping fluid to flow through and creating a release of fluid pressure, which is necessary to prevent damage to the shock absorber 20 and / or the vehicle 10.

[0023] Referring to Fig. 4 The bottom valve assembly 38 comprises a second valve body 92, a compression valve assembly 94, and an expansion valve assembly 96. The compression valve assembly 94 and the expansion valve assembly 96 are attached to the valve body 92 using a rivet 98 or a bolt and nut. The valve body 92 defines a plurality of compression passages 102 and a plurality of expansion passages 104.

[0024] The compression valve assembly 94 comprises a plurality of valve discs 106, which are preloaded against the valve body 92 by the rivet 98. During compression, the fluid in the lower working chamber 46 is pressurized, and the fluid pressure within the compression passages 102 ultimately opens the compression valve assembly 94 by opening the valve disc 106 in one of the upper passages for the expansion valve assembly 64 in a similar manner. The compression valve assembly 62 opens to allow fluid flow from the lower working chamber 46 to the upper working chamber 44, and only the "rod volume" flows through the compression valve assembly 94. The damping characteristics of the shock absorber 20 are determined by the design of the compression valve assembly 94 and the bottom valve assembly 38.

[0025] The expansion valve assembly 96 comprises a support disc 78, a valve disc 80, and a spacer disc 82. The valve disc 80 rests against the valve body 92 and closes the expansion passages 104. The spacer disc 82 is located directly between the valve disc 80 and the support disc 78, and the support disc 78 is located directly between the spacer disc 82 and the rivet 98. During rebound, the fluid pressure in the lower working chamber 46 decreases, causing the fluid pressure in the compensation chamber 52 to act against the valve disc 80. When the fluid pressure acting against the valve disc 80 exceeds the bending force of the valve disc 80, the valve disc 80 bends away from the valve body 92 to open the expansion passages 104 and allow fluid flow from the compensation chamber 52 to the lower working chamber 46.Typically, a low fluid pressure acting against the valve disc 80 causes the valve disc 80 to deflect, and the compression valve assembly 94 acts as a check valve between the compensation chamber 52 and the lower working chamber 46, generating no or only partial damping force. The damping characteristics for the rebound are controlled by the expansion valve assembly, as described above.

[0026] Although the expansion valve assembly 64 is described as comprising a spacer 84 for a plurality of valve discs 86, a holder 88, and a spring 90, it is within the scope of this disclosure to replace the expansion valve assembly 64 with the compression valve assembly 62. If the compression valve assembly 62 is used as a replacement for the expansion valve assembly 60, the valve disc 80 would be redesigned such that the damping characteristics for the shock absorber 20 are maintained during an expansion movement.

[0027] Although the compression valve arrangement 94 is comprehensively depicted as a plurality of valve discs 106, it is within the scope of the present disclosure to replace the compression valve arrangement 94 with the expansion valve arrangement 96. If the expansion valve arrangement 96 is also used as a replacement for the compression valve arrangement 94, the valve disc 80 would be redesigned so that the damping characteristics of the shock absorber 20 are maintained during a rebound movement.

[0028] Referring to the Fig. 3, Fig. 5 and Fig. Section 7 shows the components of the compression valve assembly 62 in more detail. As in the Fig. 3 and Fig. As shown in Figure 5, the first circular valve body 60 comprises a first circular outer valve web 110 and a first non-circular inner valve web 112. The first circular outer valve web 110 is depicted as a circular web whose center is positioned at the center of the first circular valve body 60. The first non-circular inner valve web 112 is depicted as a non-circular web divided into four sections AB, BC, CD, and DA. Section AB is a circular section whose center is located at the center of the first circular valve body 60. Section CD is a circular section whose center is located at a point opposite the center of the first circular valve body 60. Fig. Sections BC and DA are spaced 5 to the left. Sections BC and DA are transition sections between sections AB and CD. Sections BC and DA can be linear sections of the first non-circular inner valve land 112, they can be curved sections of the first non-circular inner valve land 112, or they can have any shape necessary to generate the required performance of the compression valve assembly 62. The valve disc 80 engages with the entire upper surface of the first circular outer and first non-circular inner valve lands 110, 112.

[0029] As in Fig. As shown in Figure 5, the area between the first circular outer valve web 110 and the first non-circular inner valve web 112 has a width in the radial direction of the first circular valve body 60, which varies in width with respect to its position in the circumferential direction.

[0030] When fluid pressure acts against the valve disc 80, which closes the area between the outer valve web 110 and the first non-circular inner valve web 112, the section of the area between the first circular outer valve web 110 and the first non-circular inner valve web 112 that has the greatest width exerts a greater force on the valve disc 80, since a larger area of ​​the valve disc 80 is exposed to the fluid pressure. Therefore, the section of the valve disc 80 that lies in the area of ​​greatest width between the valve webs 110 and 112 opens first, followed by further sections of the valve disc 80 in direct proportion to the width in these sections. The curve determining the opening of the compression valve assembly 62 can be specified by the shape of the first circular outer valve web 110 and the first non-circular inner valve web 112.

[0031] As in Fig. As shown in Figure 5, the multiple compression passages 102 are arranged only in a section of the area between the first circular outer valve web 110 and the first non-circular inner valve web 112, corresponding to a position in the circumferential direction where the width between the first circular outer valve web 110 and the first non-circular inner valve web 112 is greater than the minimum width between the first circular outer valve web 110 and the first non-circular inner valve web 112. This position of the compression passages 70 directs the fluid flow and fluid pressure directly to the wider sections on the valve disk 80, ensuring that the section of the valve disk 80 with the greatest width opens first.

[0032] Referring to the Fig. 4, Fig. 6 and Fig. Section 7 shows components of the expansion valve assembly 96 in more detail. As in the Fig. 4 and Fig. As shown in Figure 6, the second valve body 92 comprises a second outer valve web 110A and a second non-circular inner valve web 112A. The outer valve web 110A is depicted as a circular web whose center is positioned at the center of the circular valve body 92. The second non-circular inner valve web 112A is depicted as a non-circular web with four sections AA-BB, BB-CC, CC-DD, and DD-AA. Section AA-BB is a circular section whose center is positioned at the center of the valve body 92. Section CC-DD is a circular section whose center is positioned at a point opposite the center of the valve body 92. Fig. Sections BB-CC and DD-AA are transitional sections between sections AA-AB and CC-DD. Sections BB-CC and DD-AA can be linear sections of the second non-circular inner valve web 112A, curved sections of the second non-circular inner valve web 112A, or any shape necessary to generate the required performance of the compression valve assembly 62. The valve disc 80 engages with the entire upper surface of the outer and second non-circular inner valve webs 110A and 112A.

[0033] As in Fig. As shown in Figure 6, the area between the outer valve web 110A and the second non-circular inner valve web 112A has a width extent in the radial direction of the valve body 92, which varies with respect to the position in the circumferential direction of the width extent.

[0034] When fluid pressure acts against the valve disc 80, which closes the area between the outer valve web 110 and the second non-circular inner valve web 112A, the section of the area with the greatest width exerts a greater force on the valve disc 80, since a larger area of ​​the valve disc 80 is exposed to the fluid pressure. Therefore, the section of the valve disc 80 located at the greatest width of the area between the valve webs 110A and 112A opens first, followed by other sections of the valve disc 80 in direct proportion to the width of these other sections. The curve determining the opening of the compression valve assembly 62 can be specified by the shape of the outer valve web 110A and the second non-circular inner valve web 112A.

[0035] As in Fig. As shown in Figure 6, the plurality of expansion passages 104 are arranged in only one section of the area between the outer valve web 110 and the second non-circular inner valve web 112A, which corresponds to a position in the circumferential direction where the width between the outer valve web 110 and the second non-circular inner valve web 112A is greater than a minimum width between the outer valve web 110 and the second non-circular inner valve web 112A. This position of the expansion sections 104 directs the fluid flow and fluid pressure directly to sections of the valve disk 80 with a greater width, thus ensuring that the section of the valve disk 80 with the greatest width opens first.

[0036] Even though the compression valve arrangement 62 and the expansion valve arrangement 96 are shown as embodiments with clamped valve discs, it is within the scope of protection of the present disclosure to use any other valve design for shock absorbers known from the prior art, including, but not limited to, designs in which the valve disc is preloaded against the piston body or the valve body by the preloading element, such as a coil spring, a flange spring or other preloading elements.

Claims

[1] Shock absorber (20, 26) comprising: a pressure tube (30) that defines a fluid chamber; a piston arrangement (32) arranged within the pressure tube (30), wherein the piston arrangement (32) divides the fluid chamber into an upper working chamber (44) and a lower working chamber (46); a first valve arrangement which engages with the piston arrangement (32), wherein the first valve arrangement comprises a first circular valve body (60) and a first valve disk (80) which engages with the first circular valve body (60); wherein the first circular valve body (60) defines a first circular outer valve web (110) and a first non-circular inner valve web (112), wherein the first valve disk (80) engages with an entire upper surface of the first non-circular inner and first circular outer valve webs (112, 110), and wherein a center of the first circular outer valve web (110) is positioned in a center of the first circular valve body (60), characterized by , that the first non-circular inner valve web (112) is a non-circular web with a circular section (AB) having its center in the center of the first circular valve body (60), a circular section (CD) having its center at a point spaced apart from the center of the first circular valve body (60), and with transition sections (BC; DA) between the circular sections (AB; CD); wherein the first circular valve body (60) defines a plurality of compression passages (70) and a plurality of expansion passages (72); and wherein the plurality of compression passages (70) is arranged only in a section of the area between the first circular outer valve web (110) and the first non-circular inner valve web (112), which corresponds to a position in the circumferential direction where the width between the first circular outer valve web (110) and the first non-circular inner valve web (112) is greater than the minimum width between the first circular outer valve web (110) and the first non-circular inner valve web (112). [2] Shock absorber (20, 26) according to claim 1, wherein a radial distance between the first non-circular inner and the first circular outer valve web (112, 110) varies depending on a position, in circumferential direction, of the radial distance. [3] Shock absorber (20, 26) according to claim 1, further comprising: a compensating tube (36) surrounding the pressure tube (30) and a compensating chamber (42) defined between the pressure tube (30) and the compensating tube (36); a second valve arrangement engaging with a bottom valve arrangement (38) of the shock absorber (20, 26), wherein the second valve arrangement comprises a second valve body (92) and a second valve disk (106) engaging with the second valve body (92); wherein the second valve body (92) defines a second outer valve web (110A) and a second non-circular inner valve web (112A), wherein the second valve disk (106) engages with the second non-circular inner and second outer valve webs (112A, 110A). [4] Shock absorber (20, 26) according to claim 3, wherein the second outer valve bridge (110A) is a circular valve bridge. [5] Shock absorber (20, 26) according to claim 3, wherein the second non-circular inner valve web (112A) comprises a first circular section (AA-BB). [6] Shock absorber (20, 26) according to claim 5, wherein the second non-circular inner valve web (112A) comprises a second circular section (CC-DD). [7] Shock absorber (20, 26) according to claim 6, wherein the second non-circular inner valve web (112A) between the first and second circular sections (AB) comprises a first and second transition section (BB-CC, DD-AA). [8] Shock absorber (20, 26) according to claim 3, wherein a radial distance between the second non-circular inner and the second outer valve web (112A, 110A) varies depending on a position, in circumferential direction, of the radial distance. [9] Shock absorber (20, 26) according to claim 8, wherein a plurality of expansion passages (104) determined by the first circular valve body (60) are arranged circumferentially at a position between the second non-circular inner and second outer valve webs (112A, 110A) where the radial distance is greater than a smallest radial distance between the second non-circular inner and first outer valve webs (112A, 110).

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