Damping valve for shock absorber

Abstract

The invention relates to a damping valve for a vibration damper, comprising a valve disc having at least one surface which is subjected to pressure of a damping medium in a lifting direction and which is acted upon by a plurality of inflow channels in a valve body, the valve disc being preloaded by at least one closing spring against a valve seat surface contour of the damping valve body, the valve seat surface contour surrounds the outlet of the inflow channel, and wherein the valve disk performs a horizontal displacement movement relative to the valve seat surface contour as a function of a pressure acting on the pressure-bearing surface in the lifting direction and a closing force of the at least one closing spring.

Description

Technical Field

[0001] The invention relates to a damping valve for a shock absorber according to the preamble of patent claim 1 . Background Art

[0002] For the comfort and noise performance of a shock absorber, it is advantageous if the damping valve of the shock absorber has a defined opening behavior. Defined opening behavior means that the valve disk begins its opening movement at a defined area and continues from this area until it is terminated, for example, by a stop disk. In many cases, damping valves do not have a defined opening behavior because the pressure-bearing surfaces or other forces that determine the opening behavior act in an undefined manner. In damping valves with an annular groove that is essentially covered by the valve disk, since the entire annular groove is subjected to pressure during the working movement of the shock absorber, it is impossible to predict the circumferential region in which the valve disk will lift from the valve seat surface.

[0003] This operating behavior of damping valves has been known for some time, and various solutions have been developed. DE 21 09 398 A1 proposes an eccentric arrangement of the valve disk relative to the annular groove. This creates different points of force application on the valve disk, which lead to a defined opening behavior. However, it is difficult to determine the necessary eccentricity of the valve disk relative to the valve body or the flow-incoming surface in the damping valve body to achieve the desired effect.

[0004] DE 10 2010 040 458 A1 discloses an alternative solution in which the annular groove of the damping valve body has a meandering outer valve seat surface, resulting in varying lever arms in the circumferential direction. In this solution, eccentricity is achieved in the pressure-bearing flow-incoming surface on the underside of the valve disk. However, even with this solution, a loss of pressure-bearing surface must be accepted compared to an annular groove with constant width.

[0005] DE 10 2018 221 290 A1 proposes a damping valve having an annular groove with a constant cross-section in the circumferential direction. Unlike this, at least one of the valve seat surfaces radially delimiting the annular groove is designed with a profile that produces both line contact and surface contact between the valve seat surface and the valve disc resting on it within a defined circumferential region. Due to the different adhesion effects resulting from the line contact and surface contact, different opening forces can act on the valve disc, thereby causing a defined lifting motion of the valve disc. This solution eliminates any loss of pressure-bearing surface. However, creating a profile on at least one valve seat surface is difficult. Summary of the Invention

[0006] The object of the present invention is to provide a further solution to the problems of the lifting movement defined above.

[0007] This object is achieved in that the valve disk executes a horizontal displacement movement relative to the valve seat surface contour as a function of the pressure force acting in the lifting direction on the pressurized surface and the closing force of at least one closing spring.

[0008] The forces acting on the valve disc tend to displace the valve disc, thereby reinforcing the defined, one-sided valve opening behavior. This displacement movement does not require additional measures such as special adjustment devices.

[0009] To support the displacement movement, at least one valve disk is movably supported on a retaining pin on the damping valve body side. The retaining pin can be formed by a pin separate from the damping valve body, but can also be formed by a stepped geometry of the damping valve body.

[0010] Preferably, the valve disk has a limiting contour in the region of the receiving opening for the retaining pin, the major axes of which have different lengths. The limiting contour can correspond, for example, to the envelope of an oblong hole, an ellipse or an egg.

[0011] In order to support the mobility of the valve disc, the valve disc is supported so that it can move completely axially against the closing spring. In addition to the closing force of the closing spring, there should be no additional loading force in the valve disc assembly.

[0012] Preferably, multiple closing springs arranged in a ring should apply the closing force to the valve disk. This punctiform application of the closing force creates an area on the valve disk where the closing force is lower. The lifting movement typically begins there, with the relative deformation of the valve disk and the support provided by the closing springs causing the displacement movement of the valve disk.

[0013] To support the effect of the self-reinforcing, one-sided lifting movement of the valve disc, a support disc can also be mounted rotatably in the circumferential direction relative to the valve disc. Additionally or alternatively, the support disc can be mounted so as to be radially displaceable relative to the valve disc. The relative movement between the valve disc and the support disc, in particular the closing spring, promotes the desired lifting behavior of the valve disc.

[0014] In order to ensure a particularly effective supporting effect of the closing spring, the closing spring is fixedly connected to the supporting disk in the circumferential direction in order to limit the lifting of the valve disk.

[0015] According to an advantageous dependent claim, the closing spring is formed by an elastomeric element. The elastomeric element simplifies the use of a single spring.

[0016] To maximize the mobility of the valve disc, a cover plate can be optionally attached to the valve disc, supported axially movably in the direction of the closing spring. The inner diameter of the cover plate is smaller than the supporting surface of the axial retaining element, for mounting the valve disc on the damping valve body. This additional cover plate prevents the valve disc from disengaging from the locking head, thereby axially supporting the valve disc on the damping valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described with reference to the following drawings, wherein:

[0018] Figure 1 shows a cross-sectional view of an exemplary valve design;

[0019] Figure 2 Shown according to Figure 1 Exploded view of the damping valve;

[0020] Figure 3 Shown according to Figure 1 and Figure 2 A top view of the valve disc;

[0021] Figure 4 according to Figure 1 shows the lifting motion of the valve disc; and

[0022] Figure 5 according to Figure 3 The lifting movement of the valve disc is shown. DETAILED DESCRIPTION

[0023] Figure 1 A section through a shock absorber 1 is shown in the region of the damping valve 3. In this exemplary embodiment, the damping valve 3 is shown as a bottom valve in a twin-tube shock absorber, but the invention is in no way limited to this spatial or functional design.

[0024] The shock absorber 1 comprises a working cylinder 5 which is completely filled with a damping medium and in which a displacement element (not shown) is located at the piston rod. The damping medium is pressed through the damping valve 3 into the compensation chamber 7. The annular compensation chamber 7 is delimited on the outside by the reservoir tube 9 and on the inside by the working cylinder 5. The end-side bottom 11 closes the compensation chamber 7 and, if necessary, also carries the coupling mechanism 13 shown by way of example. The bottom 11 also supports the damping valve body 15 of the damping valve 3.

[0025] The damping valve body 15 comprises at least one through-channel 17, but preferably a first group of through-channels, which serve to allow fluid to flow from the working space 19 in the working cylinder into the compensation space 7 when the extruder is retracted into the working space 19. The at least one through-channel 17 is at least substantially closed by at least one valve disk 21, in this case by a valve disk group.

[0026] At least one through-channel 23 is arranged on the larger pitch circle of the damping valve body 15. During the displacement movement of the extruder from the working cylinder 5, flow flows through this through-channel in the direction of flow from the equalization chamber 7 toward the working chamber 19 in the working cylinder 5. At least one valve disk 25 also rests on the valve seat surface of the damping valve body 15 on the outlet side of the through-channel 23. The valve disk 25 is equipped with a support disk 27, in this case an elastic disk, to counteract the lifting movement of the valve disk 25. The support disk has a receiving opening 29 for an elastomeric element 31, which extends axially through the support disk 27 and is seated with a retaining head 35 on the back side facing away from the valve disk 25. The support disk 27 is supported so that it can rotate in the circumferential direction and move radially relative to the valve disk 25. The elastomeric element 31 forms a separate closing spring, which, arranged in an annular manner, applies the closing force to the valve disk 25. The closing spring is fixedly connected to the support disk 27 in the circumferential direction by axially passing through the support disk 27 to limit the lifting of the valve disk 25. Generally, the through-channel 17 and the at least one valve disk 21 of the pressure damping valve are designed based on a larger pressure difference than the through-channel 23 and the valve disk 25.

[0027] Combine Figure 2 It can be clearly seen that the connecting element 37, in this case a fastening rivet, passes through the damping valve body 15. The flat head 39 of the fastening rivet 37 clamps the valve disk assembly 21 against the annular clamping surface 41 of the damping valve body 15 in the direction of flow of the damping medium into the compensation chamber 7. Functionally, the fastening rivet forms a retaining pin 37 on the damping valve body, relative to which the at least one valve disk 25 is mounted so as to be radially displaceable.

[0028] On the opposite cover side of the damping valve body 15, the outer valve seat surface 41 and the inner valve seat surface 43 delimit an annular groove 45, which forms the outlet side of the through-channel 23 with respect to the flow direction of the damping medium from the compensation chamber 7 into the working chamber 19 of the working cylinder 5. This shape of the valve seat surface is also merely an example. An annular valve seat surface may also be provided around each through-channel.

[0029] If necessary, a throttle ring 47 can be placed on this cover side, which causes a first pressure drop in the inflow direction into the through-channel 17. On the damping valve body 15, a seating surface 49 of the damping valve body 15 for the throttle ring 47 is located axially deeper than the two opposite seating surfaces 41, 43 for the valve disk 25, which protrude therefrom.

[0030] Both the valve disc 25 and the support disc 27 have a star-shaped profile 51, 53 with a notch, which allows the damping medium to enter the through-channel 17. The valve disc 25 and the support disc 27 are both mounted on a rod region 57 of a spring carrier element 59, on which the movably mounted support disc 27 is axially supported on a support surface 61 due to the axial preload of the elastomer element 31 ( Figure 1 ).

[0031] The shaft region 57 of the spring support element 59 axially overlaps the valve seat surfaces 41, 43 for the valve disk 25 and thus clamps the throttle ring 47 against the seating surface 49 of the damping valve body 15. The locking head 65 of the connecting element 37 ensures the preloading of the spring support element 59 with its shaft region 57. Figure 1 , a free space 63 is present between the support disk 27 and the valve disk 25 in the area of ​​the inner diameter, so that the support disk 27 can be moved in the direction of the valve disk 25 against the preload force of the elastomeric element 31. On the other hand, the valve disk 25 is also supported for full axial movement against the closing spring 31.

[0032] Figure 3 The valve disc 25 is shown in a top view. The inner reference circle 65 symbolically represents the diameter of the stem region 57. The dot-dash line shows the limiting contour 67 at the inner diameter of the valve disc 25. The fingers 69 pointing radially inwards define a passage cross section 71 for the flow into the through-channel 17 (see Figure 1 The main axes 75 , 77 of the delimiting contours have different lengths. In principle, the receiving opening 73 can also have a circular geometry that enables a radial movement path of the valve disk 25 relative to the valve seat surfaces 41 , 43 .

[0033] Another circle indicated by a dashed line represents a cover disk 79 which is optionally attached to the valve disk 25 and supported so as to be axially movable in the direction of the closing spring 31 (see FIG. Figure 1 ). Its inner diameter is smaller than the outer diameter of the support surface 61 of the retaining pin for mounting the valve disk on the damping valve body 15. However, the outer diameter of the cover disk 79 is dimensioned so that it overlaps the valve disk 25 even during the maximum radial movement of the valve disk 25 relative to the shaft region 57. In any case, the access cross section 71 to the through-channel 17 is retained. The cover disk 79 is intended to prevent the valve disk 25 from being able to escape from the support surface 61 if the receiving opening 73 is particularly large.

[0034] exist Figure 4 and Figure 5 The lifting behavior and interaction of the valve disc 25 with the support disc 27, in particular the closing spring 31, are shown in the combination of FIG. The unilateral lifting behavior of the valve disc 25 is caused, for example, by the contours of the valve seat surfaces 41, 43 and the shape of the annular groove 45. An initial wave-like lifting movement occurs, which, for example, Figure 4Contact with the elastic body 31 is brought about. Depending on the pressure acting on the pressure-bearing surface of the valve disc 25 in the lifting direction and the closing force of the at least one closing spring 31, the valve disc 25 performs a horizontal displacement movement relative to the valve seat surface contour or valve seat surfaces 41, 43. In this case, not only the valve disc 25 can perform displacement movement. The support disc 27 can also rotate in the circumferential direction or displace radially. To this end, the support disc 27 can also have a limiting contour 67 depending on the design of the valve disc 25. Regardless, the two discs 25, 27 are displaced relative to each other, so that the relationship between the valve disc 25, the damping valve body 15, and the closing spring 31 of the support disc 27 changes slightly during the next lifting of the valve disc. The gap between the receiving opening of the valve disc 25 and the shaft area 57 represents the maximum possible radial displacement of the valve disc 25. After the valve disc 25 is initially lifted from the valve seat surfaces 41, 43, it does not necessarily immediately assume its final position. This is typically an iterative process, with orientation designed to enhance a defined, unilateral valve disc lifting movement.

[0035] Reference Signs List

[0036] 1 shock absorber

[0037] 3 Damping valve

[0038] 5 working cylinders

[0039] 7 Compensation Space

[0040] 9 container tube

[0041] 11 bottom

[0042] 13 Connecting mechanism

[0043] 15 Damping valve body

[0044] 17 Through Channel

[0045] 19 Workspace

[0046] 21 Valve disc

[0047] 23 Through Channel

[0048] 25 valve disc

[0049] 27 Support Plate

[0050] 29 Receiving opening

[0051] 31 Elastomer elements

[0052] 33 dorsal

[0053] 35 Keep Head

[0054] 37 Retaining pin

[0055] 39 flat head

[0056] 41 External valve seat surface

[0057] 43 Inner valve seat surface

[0058] 45 annular groove

[0059] 47 throttle ring

[0060] 49 Placement surface

[0061] 51 Centering contour

[0062] 53 Centering contour

[0063] 55 centering diameter

[0064] 57-bar area

[0065] 59 Spring bracket element

[0066] 61 Support surface

[0067] 63 Free Space

[0068] 65 reference circle

[0069] 67 Restricted Contour

[0070] 69 finger-like part

[0071] 71 Passage Section

[0072] 73 receiving opening

[0073] 75 spindle

[0074] 77 Spindle

[0075] 79 Cover the plate.

Claims

1. A damping valve (3) for a shock absorber (1), comprising a valve disk (25) having at least one surface which is acted upon by the pressure of a damping medium in a lifting direction, said surface being acted upon by a plurality of inflow channels (23) in a valve body (15) of the damping valve, wherein: The valve disc (25) is preloaded toward the valve seat surface contour (41, 43, 45) of the damping valve body (15) by at least one closing spring (31), wherein the valve seat surface contour (41, 43, 45) surrounds the outlet of the inflow channel (23), characterized in that the valve disc (25) performs a horizontal displacement movement relative to the valve seat surface contour (41, 43, 45) depending on the pressure acting on the pressure-bearing surface in the lifting direction and the closing force of the at least one closing spring (31).

2. The damping valve (3) according to claim 1, characterized in that The at least one valve disk (25) is mounted radially displaceably on a retaining pin (37) on the valve body side of the damping valve.

3. The damping valve (3) according to claim 2, characterized in that The valve disk (25) has a limiting contour (67) in the region of a receiving opening (73) for the retaining pin (37), the main axes (75, 77) of which have different lengths.

4. Damping valve (3) according to at least one of claims 1 to 3, characterized in that The valve disc (25) is supported so as to be fully axially movable against the closing spring (31).

5. The damping valve (3) according to claim 4, characterized in that A plurality of closing springs (31) arranged in an annular shape introduce the closing force into the valve disk (25).

6. Damping valve (3) according to at least one of claims 1 to 5, characterized in that A support disk (27) is supported so as to be rotatable relative to the valve disk (25) in the circumferential direction.

7. Damping valve (3) according to at least one of claims 1 to 6, characterized in that The support disc (27) is supported so as to be movable radially relative to the valve disc (25).

8. Damping valve (3) according to at least one of claims 5 to 7, characterized in that The closing spring (31) is fixedly connected to the support disk (27) in the circumferential direction so as to limit the lifting of the valve disk (25).

9. The damping valve (3) according to claim 8, characterized in that The closing spring (31) is formed by an elastomeric element.

10. Damping valve (3) according to at least one of claims 1 to 9, characterized in that A cover disk (79) is attached to the valve disk (25) in the direction of the closing spring (31) and is supported so as to be axially movable. The inner diameter of the cover disk is smaller than the outer diameter of the support surface (61) of the axial retaining pin (37) for mounting the valve disk on the damping valve body (15).

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