DAMPING-VALVE DEVICE WITH A PROGRESSIVE DAMPING-FORCE CHARACTERISTIC CURVE

Abstract

A damping valve device for a vibration damper has a restriction in connection with a valve element movable from an open position into a restriction position depending on the flow velocity of a damping medium inside the restriction. The valve element, as a variable-diameter annular element, moves in closing direction with increasing flow velocity of the damping medium within an annular groove of a valve support. The annular groove is constructed as a pressure space having at least one inflow orifice and at least one outflow orifice. The valve element is positioned at a radial distance from an annular groove base by centering elements.

Claims

1.-8. (canceled)

9. A damping valve device for a vibration damper, comprising: a restriction in connection with a valve element that is movable from an open position into a restriction position based on a flow velocity of a damping medium inside the restriction, wherein the valve element, as a variable-diameter annular element, moves in closing direction with increasing flow velocity of the damping medium within an annular groove of a valve support, wherein the annular groove is configured as a pressure space having at least one inflow orifice and at least one outflow orifice, and wherein the valve element is positioned at a radial distance from an annular groove base by centering elements.

10. The damping valve device according to claim 9, wherein the centering elements are formed by segments supported at the annular groove base.

11. The damping valve device according to claim 10, wherein the segments are combined to form a support ring.

12. The damping valve device according to claim 11, wherein the support ring forms the valve support with at least one spacer sleeve and two cover disks.

13. The damping valve device according to claim 10, wherein the segments have a smaller axial height than that of the pressure space.

14. The damping valve device according to claim 10, wherein a lateral surface of the valve element carries the segments.

15. The damping valve device according to claim 14, wherein the lateral surface of the valve element has receiving openings for the segments.

16. Damping valve device according to claim 9, wherein at least one side surface of the annular groove has centering elements for the valve element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Aspects of the invention will be described in more detail referring to the following description of the figures. In the drawings:

[0018] FIG. 1 is a fragmentary view of a vibration damper in the region of the damping valve device;

[0019] FIGS. 2-4 are the damping valve device according to FIG. 1 in detail; and

[0020] FIGS. 5-7 are valve supports.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0021] FIG. 1 shows a damping valve device 1 for a vibration damper 3 of optional construction type, shown only in a fragmentary manner. In addition to the damping valve device 1, the vibration damper 3 comprises a first damping valve 5 with a damping valve body which is constructed as a piston 7 and attached to a piston rod 9.

[0022] The damping valve body 7 divides a cylinder 11 of the vibration damper into a work space 13 on the piston rod side and a work space 15 remote of the piston rod, both of which are filled with damping medium. Passages 17; 19 for each through-flow direction are constructed on different pitch circles in the damping valve body 7. The configuration of the passages 17; 19 is merely exemplary. An outlet side of the passages 17; 19 is at least partially covered by at least one valve disk 21; 23.

[0023] For example, a valve support 25 of the damping valve device 1 is secured directly to the piston rod 9.

[0024] The valve support 25 has a circumferential annular groove 27 in which a valve element 29 with variable diameter is guided. This valve element 29 is radially movable or radially elastic and forms a valve body for a restriction 31 as part of the damping valve device 1. The valve element 29 forms the restriction 31 with an inner wall of the cylinder 11 which constitutes a flow guiding surface 33.

[0025] The valve element 29 is outfitted with a return spring 35 as is shown, for example, in an enlarged view in FIG. 2. A variable restriction cross section 39 which produces an additional damping force is situated between the flow guiding surface 33 and an outer lateral surface 37 of the valve element 29.

[0026] At a piston rod velocity in a first operating range, e.g., less than 1 m/s, the restriction 31 is completely open. The damping force is then generated only by the passages 17; 19 in combination with the valve disks 21; 23. With flow impinging on the valve disks 21; 23, the valve disks 21; 23 lift from their valve seat surface 41; 43. The lifting movement is limited in each instance by a supporting disk 45; 47.

[0027] In a second operating range with a piston rod velocity greater than the limit velocity of the first operating range, i.e., greater than 1 m/s, which was indicated by way of example, the valve element 29 moves into a restriction position and, in so doing, executes a closing movement in direction of the flow guiding surface 33. As a result of the high flow velocity of the damping medium in the restriction 31 which is shaped as an annular gap, a negative pressure forms, which leads to a radial expansion of the valve element 29. However, in order to preclude a blockage of the restriction 31 under any circumstances, the defined minimum cross-sectional opening area can be maintained, e.g., by the return spring 35.

[0028] FIG. 2 shows a detail of the damping valve device 1 according to FIG. 1. It can be seen from the enlargement that the annular groove 27, together with an inner lateral surface 55 of the valve element 29, annular groove side surfaces 57; 59 of the cover disks 51; 53 and an annular groove base 61, forms a pressure space 63 which is connected to the work space of the vibration damper 3 via at least one inflow orifice 65 and an outflow orifice 67. The pressure space 63 reinforces the negative pressure condition existing in the restriction 37 via a radially outwardly directed force component expanding the valve element 29. The functional designations of inflow orifice and outflow orifice are to be switched analogously for an oppositely impinging flow of the damping valve device.

[0029] The construction of the valve support 25 will be apparent when FIGS. 2, 3, and 4 are viewed in conjunction. The valve support 25 comprises, inter alia, the two cover disks 51; 53 that are connected to one another via a support ring 69. All three component parts are centered at the piston rod 9 via their through openings 71; 73; 75.

[0030] The valve element 29 according to one aspect of the invention comprises two legs 29A; 29B that are connected to one another via a pivot bearing 77. The pivot bearing 77 has no connection to the valve support 25 as is shown by the cover disks 51; 53 which are closed in the relevant surface region. Consequently, the valve element 29 can be arranged in any rotational orientation within the annular groove 27. The valve element 29 is positioned at a radial distance from the annular groove base 61 by centering element 79 so that the valve element 29 cannot occupy any random radial initial position inside the annular groove 27.

[0031] The centering element 79 is formed by segments 81, which are supported at the base 61 of the annular groove 27. As shown in FIGS. 2 to 4, the segments 81 are combined at the support ring 69. The segments 81 have a lower axial height than that of the pressure space 63 such that the damping medium in the pressure space 63 can flow around the segments 81. The segments 81 can be constructed comparatively flat because the pressure inside of the pressure space 63 is everywhere the same and, therefore, does not exert a particularly high load on the segments 81.

[0032] In the initial position of the damping valve device 1, the valve element 29 contacts the segments 81 by its inner lateral surface 55 (FIG. 2) and accordingly has a defined cross section of the restriction 31 in circumferential direction. It may very well be desirable for the segments 81 to have a different radial extension and, therefore, for the restriction cross section 39 to also result differently along the circumference of the valve element 29. But because of the centering elements 79, the different restriction cross section 39 is not undefined but rather is optimized for a desired damping force characteristic of the damping valve device.

[0033] FIG. 5 shows a modification of the valve support from FIGS. 2 to 4. By contrast, the support ring 69 forms the valve support 25 with at least one spacer sleeve 83 and two cover disks 51; 53. The support ring 69 is preferably constructed thin enough to enable production by punching. The axial installation space and, therefore, the surface area of the valve element 29 acted upon by pressure is determined by the spacer sleeves 83. Two spacer sleeves 83 are provided. However, the support ring 69 can also be arranged directly on one of the cover disks 51; 53. Like the rest of the component parts 51; 53, 69 of the valve support 25, the spacer sleeves 83 are also centered at the piston rod 9.

[0034] FIG. 6 shows a valve support 25 with a single spacer sleeve and two cover disks 51; 53 which form the annular groove 27. By contrast, the inner lateral surface 55 of the valve elements 29 supports the segments 81. The inner lateral surface 55 of the valve element 29 preferably has receiving openings 85 for the segments 81 in order to minimize the production expenditure for the centering elements.

[0035] FIG. 7 shows a valve support 25 with a centering function for the valve element. At least one side surface 57 of the annular groove 27 has the centering elements for the valve element. The centering elements 77 are achieved by a shoulder 87 at one of the two cover disks 51; 53. Only a slight axial extension of the shoulder 87 is needed for the centering elements 77 so that the shoulder 87 is also producible by an embossment of the cover disks 51; 53. A plurality of axial projections 89 are formed at a cover surface 91 of the valve element 29 in direction of the annular groove side surface 57 of the cover disk 51 which also has the shoulder 87. The plurality of axial projections 89 cooperate with the shoulder 87 to exercise the centering function for the valve elements 29 inside of the pressure space 63. A single spacer sleeve 83 without special shaping is also sufficient in this instance.

[0036] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.