Damper valve device for a shock absorber

Abstract

The invention relates to a damping valve device with a throttle point for a shock absorber, comprising a valve seat with an annular groove, in which an annular valve element is arranged, the diameter of which can be varied, wherein the valve element together with a flow guide forms the throttle point, the cross section of which decreases with increasing flow speed of the damping medium inside the throttle point, the annular groove forms, by means of the side of the valve element and the annular groove side of the valve seat, a pressure chamber, which is connected to the working chamber of the shock absorber via an inflow opening and an outflow opening, wherein the outflow cross section of the outflow opening is defined by the annular groove side and the cover side of the valve element, the size of which is determined by the radial elongation of the valve element relative to the valve seat.

Description

Technical Field

[0001] The present invention relates to a damping valve device for a vibration damper as described in the preamble of claim 1. Background Technology

[0002] A damping valve device is known from document DE102016210790A1, in which a valve element that can be widened radially forms a throttling section together with a guide surface. This throttling section generates a greater damping force with increasing flow velocity by reducing the size of the throttling cross section, thereby making it follow a progressive damping force characteristic curve.

[0003] The valve element is housed in an annular groove and preloaded radially inward by a resilient retaining ring. The valve element may have a radial slit to reduce the force required for widening movements.

[0004] For this type of throttling section, there is a fundamental problem: the asymptotic trend of the damping force characteristic curve is very pronounced. Once the limiting flow velocity of the damping medium inside the throttling section is exceeded, the damping force suddenly and drastically increases. This operating characteristic may be acceptable for some applications, but it is a disadvantage for others. Summary of the Invention

[0005] The purpose of this invention is to minimize the disadvantages known from the prior art.

[0006] This objective is achieved by the annular groove forming a pressure chamber via the side of the valve element and the side of the annular groove of the valve seat. This pressure chamber is connected to the working chamber of the damper via an inlet opening and an outlet opening, wherein the outlet opening has an outlet cross-section defined by the side of the annular groove and the cover side of the valve element, and the size of the outlet cross-section is determined by the radial elongation of the valve element relative to the valve seat.

[0007] This achieves pressure control that depends on the regulating path of the valve element. Taking full advantage of this effect, the valve element's diameter is delayed when the outflow cross-section is large, while the valve element's response is more direct when the outflow cross-section is small.

[0008] The outflow cross-section of the outflow opening preferably has its maximum value at the initial position of the valve element associated with the maximum cross-section of the throttling portion. This initiates a slow closing motion of the valve element, resulting in a later asymptotic progression of the damping force in the damping force characteristic curve.

[0009] Optionally, the cover side has a rib structure. The rib structure provides an always-open outflow channel that affects the outflow cross-section. Furthermore, to minimize friction between the valve element and the valve seat, a guide edge is constructed on the side of the annular groove that does not engage with the contour of the cover side.

[0010] The rib structure is preferably constructed only on the outer surface area of ​​the cover side of the valve element. The radially inwardly closed profile of the cover side allows for the reduction of the outflow cross-section of the outflow opening in the simplest manner.

[0011] In the case of standardized valve elements, the rib structure can be very easily adapted to the desired damping force characteristic curve of the damping valve device by at least one additional ring element.

[0012] Another measure for determining the size of the outflow cross-section of the outflow opening is that the annular groove side of the valve seat facing the covered side has a groove extending in the circumferential direction.

[0013] It is also possible that, when designing the groove in the valve seat, the groove on the side of the annular groove is formed by an additional disc.

[0014] The auxiliary disc is preferably supported on the outer edge of the valve seat. If the auxiliary disc is fastened to the valve seat in a force-transmitting or form-fitting manner, slight material wear will occur, and the auxiliary disc can be easily removed from the outer edge of the valve seat.

[0015] To achieve a flexible transition between the maximum open cross-section and the minimum open cross-section of the outflow opening, the grooves in the side of the annular groove have different widths on the circumference. Attached Figure Description

[0016] The invention will be described in detail below with reference to the accompanying drawings.

[0017] in:

[0018] Figure 1 A cross-sectional view of the shock absorber in the area of ​​the damping valve assembly is shown;

[0019] Figure 2 It shows according to Figure 1 Detailed diagram of the damping valve device;

[0020] Figure 3 A detailed diagram of the valve seat is shown;

[0021] Figure 4 It shows according to Figure 2 Alternatives to the implementation methods. Detailed Implementation

[0022] Figure 1 A damping valve device 1 is shown, partially shown, for a damper 3 of any structural form. In addition to the damping valve device 1, the damper 3 also includes a first damping valve 5 with a damping valve body configured as a piston 7, which is fastened to a piston rod 9.

[0023] The damping valve body 7 divides the cylinder 11 of the damper into a working chamber 13 on the piston rod side and a working chamber 15 away from the piston rod, both of which are filled with damping medium. The damping valve body 7 is constructed with flow passages 17 and 19 for one flow direction on different pitch circles. Only illustrative examples of the flow passage design are considered. At least one valve disc 21 or 23 at least partially covers the outlet side of the flow passages 17 and 19.

[0024] In addition, the shock absorber has a pull stop 25 that contacts a stop surface on one side of the cylinder, such as the piston rod guide 27, from the defined extension movement of the piston rod 9.

[0025] The traction stop 25 includes a valve seat 29, which is directly fixed to the piston rod via a form-fit connection. An annular elastic element 31 is provided on the upper side of the valve seat 29, which is held in place by a small radial prestress even when the piston rod 9 oscillates. The elastic element 31 acts as an additional support spring from the stop point on the stop surface.

[0026] The valve seat 29 has a surrounding annular groove 33 in which a valve element 35 of variable diameter is guided. This valve element 35 is radially movable or radially elastic and forms a valve body for a throttling portion 37 as part of a damping valve device 1. The valve element 35 forms the throttling portion 37 together with the inner wall 39 of the cylinder 11, where the inner wall 39 is a guide surface. In principle, the invention can also be implemented in a valve seat dependent on a pull stop.

[0027] The valve element 35 carries the return spring 41 on its outer side, for example, in the form of a retaining ring. A variable throttling cross section 45 exists between the inner wall 39 and the outer surface 43 of the valve element 35, which generates an additional damping force.

[0028] When the piston rod speed is within a first operating range, for example, less than 1 m / s, the throttling section 37 is fully open. The damping force is then generated solely by the flow passages 17 and 19 connected to the valve discs 21 and 23. When flow occurs into the valve discs 21 and 23, they are lifted off their seat surfaces 47 and 49. This stroke is defined by the support discs 51 and 53, respectively.

[0029] In a second operating range with a limit speed greater than the first operating range, i.e., greater than the piston rod speed of 1 m / s given exemplarily, the valve element 35 rotates into the throttling section and performs a closing movement toward the guide surface 39 there. Due to the higher flow velocity of the damping medium, a negative pressure is formed in the throttling section 37, which is formed as an annular gap, causing radial widening of the valve element 35. However, in order to prevent the throttling section 37 from becoming blocked under any circumstances, the defined minimum cross-sectional area is maintained by the return spring 41.

[0030] Figure 2 It shows Figure 1 The enlarged view shows a damping valve assembly fastened to the piston rod 9 using various fastening techniques. As can be seen in the enlarged view, the annular groove 33 forms a pressure chamber 63 via the inner surface 55 of the valve element 35, the sides 57 and 59 of the annular groove, and the bottom surface 61 of the annular groove. This pressure chamber is connected to the working chamber 13 of the damper 3 via an inflow opening 65 and an outflow opening 67. The pressure chamber 63 generates a radially outward force that widens the valve element 35, supporting the negative pressure present in the throttling section 37.

[0031] In order to allow the pressure level established in the pressure chamber 63 to be released again, thereby enabling the damping valve device 1 to switch back to its maximum throttling cross section, the pressure chamber 63 has an outlet opening 67. However, the outlet opening 67 is not formed by an axial opening in the valve seat 29, but by the annular groove side 59 of the valve seat 29 and the cover side 69 of the valve element 35.

[0032] However, the cross-section of the outflow opening 67 is not constant, but its size is determined by the radial elongation of the valve element 35 relative to the valve seat 29.

[0033] When the outflow cross-section has its maximum value in the initial position of the valve element associated with the maximum cross-section of the throttling section 37, it proves to be beneficial to vehicle comfort. When the throttling section 37 is fully open, the minimum damping force is generated, so the valve element 35 only achieves the closing movement toward the guide surface 39, i.e., the inner wall of the cylinder 11, after a certain pressure has been formed in the pressure chamber 63. Pressure buildup is achieved through a larger outflow cross-section.

[0034] The inner side 55 of the valve element 35 is inclined toward the pressure chamber 35. When pressure is applied, the inclined side 55 provides a vertical component of force that causes the valve element 35 to move toward the annular groove side 59 opposite the inflow opening 65. Therefore, at the start of pressure buildup, when the cover side 69 of the valve element 35 abuts against the annular groove side 59, a greater outflow cross-section with a greater height can be provided compared to the case where pressure is built up earlier. To form the prescribed outflow cross-section, the cover side 69 has a rib structure 71. A radial groove 73 is formed by the rib structure 71, and the outflow cross-section is defined by its cross-section.

[0035] Optionally, the rib structure 71 is implemented only on the outer surface region 75 of the cover side 69 of the valve element 35. The radially inner surface region 77 is flat and without profile. The axial elongation of the closed inner surface region 77 can also be chosen so that the guide edge 79, together with the rib structure 71 and the inner surface region 77, forms a spool valve on the annular groove side 59, which keeps at least the remaining cross-section of the outflow opening 67 open at all times.

[0036] In principle, the rib structure 71 can be molded into the cover side 69. The dashed line below the cover side is intended to symbolize that the rib structure can also be formed by at least one additional ring element 81.

[0037] Another component of the slide valve described above may form an annular groove side 59 facing the covered side, the annular groove side having a groove 83 extending in the circumferential direction, which partially defines the outflow cross-section of the outflow opening. A particularly large outflow cross-section exists in the region of the groove 83. In this respect, it is possible that the groove 83 of the annular groove side 59 is formed by an auxiliary disc 85, which is preferably supported on the outer edge 87 of the valve seat 29.

[0038] Combination Figure 2 and Figure 3 It is clear that the groove 83 in the side 59 of the annular groove can have different widths on the circumference in order to prevent the outflow cross-section of the outflow opening 67 from suddenly narrowing.

[0039] Figure 4A variant of the damping valve device 1 is shown, in which the rib structure of the cover side 69 is omitted. Instead, the cover side is divided into a radially inwardly protruding region 89 and an external surface region 75. The protruding region 89 has a height "h" smaller than the height "H" of the guide edge 79, so that no form-fit connection is formed between the protruding region 89 of the cover side 69 of the valve element 35 and the groove 83 in the valve seat 29. Furthermore, the guide edge 79 is so far separated from the protruding region 89 in its radial position that no form fit is formed between the protruding region 89 and the guide edge 79, even in the maximum widening position of the valve element 35. Here, a spool valve is also formed on the cover side 69 and the annular groove side 59 of the valve element 35, by means of which the cross-section of the outlet opening can be changed according to the radial widening movement of the valve element 35.

[0040] List of reference numerals in the attached diagram:

[0041] 1 Damping valve device

[0042] 3. Vibration dampers

[0043] 5 First damping valve

[0044] 7 Damping valve body

[0045] 9 Piston rod

[0046] 11 Cylinder

[0047] 13 Working chamber on one side of the piston rod

[0048] 15. Working chamber away from the piston rod

[0049] 17. Crossflow channel

[0050] 19 Crossflow Channel

[0051] 21 Valve disc

[0052] 23 Valve disc

[0053] 25. Traction stop

[0054] 27 Piston rod guide section

[0055] 29 Valve seat

[0056] 31 Elastic element

[0057] 33 Annular groove

[0058] 35 Valve Components

[0059] 37. Throttling location

[0060] 39 Inner wall

[0061] 41. Return spring

[0062] 43 Side View

[0063] 45 Throttling cross section

[0064] 47 Valve seat face

[0065] 49 Valve seat face

[0066] 51 Support level

[0067] 53 Support level

[0068] 55 Inner side

[0069] 57. Side of the annular groove

[0070] 59. Side of the annular groove

[0071] 61 Bottom surface of the annular groove

[0072] 63 Pressure Chamber

[0073] 65 Inflow Opening

[0074] 67. Outflow opening

[0075] 69 Coverage side

[0076] 71-rib structure

[0077] 73 Radial groove

[0078] 75 External surface area

[0079] 77 Internal surface area

[0080] 79 Guided Edge

[0081] 81 Additional ring element

[0082] 83 slots

[0083] 85 Additional Discs

[0084] 87 Outer edge

[0085] 89. Raised area

Claims

1. A damping valve device (1) for a shock absorber (3) having a throttling portion (37), the damping valve device comprising a valve seat (29) having an annular groove (33) in which a valve element (35) of variable diameter is arranged, wherein the valve element (35) together with a guide surface (39) forms the throttling portion (37), the cross-section of the throttling portion decreasing as the flow velocity of the damping medium inside the throttling portion (37) increases, characterized in that, The annular groove (33) forms a pressure chamber (63) by means of the side (43) of the valve element (35) and the annular groove side (57, 59) of the valve seat (29). The pressure chamber is connected to the working chamber (13) of the damper (3) via an inlet opening (65) and an outlet opening (67). The outlet opening (67) is defined by the annular groove side (59) and the covering side (69) of the valve element (35). The size of the outlet opening (67) is determined by the radial elongation of the valve element (35) relative to the valve seat (29).

2. The damping valve device according to claim 1, characterized in that, The outflow cross-section of the outflow opening (67) has a maximum value at the initial position associated with the maximum cross-section (45) of the valve element (35) and the throttling portion (37).

3. The damping valve device according to claim 1 or 2, characterized in that, The cover side (69) has a rib structure (71).

4. The damping valve device according to claim 3, characterized in that, The rib structure (71) is constructed on the surface region (75) outside the cover side (69) of the valve element (35).

5. The damping valve device according to claim 4, characterized in that, The rib structure (71) is formed by at least one additional ring element (81).

6. The damping valve device according to claim 5, characterized in that, The annular groove side (59) facing the cover side (69) has a groove (83) extending in the circumferential direction, which at least partially defines the outflow cross section of the outflow opening (67).

7. The damping valve device according to claim 6, characterized in that, The groove (83) on the side (59) of the annular groove is formed by an auxiliary disk (85).

8. The damping valve device according to claim 7, characterized in that, The auxiliary disc (85) is supported on the outer edge (87) of the valve seat (29).

9. The damping valve device according to claim 8, characterized in that, The grooves (83) in the side (59) of the annular groove have different widths on the circumference.

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