Adjustable damping valve device for shock absorber

Abstract

The invention relates to an adjustable damping valve arrangement for a shock absorber, comprising a primary valve for hydraulically controlling a primary valve, the damping valve arrangement having a check valve arrangement for rectifying a control volume flow from a working space of the shock absorber to the primary valve, characterized in that the check valve arrangement is arranged in the primary valve. A primary valve body of the primary valve has a first pressure-bearing surface (D1) for an incoming flow from the first working space and a second pressure-bearing surface (D2) for an incoming flow from the second working space.

Description

Technical Field

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

[0002] DE 44 18 972 A1 relates to an adjustable damping valve arrangement comprising a valve housing on the piston rod of a shock absorber. The functional advantage of this damping valve arrangement is that a single fore-stage valve is used to actuate the main-stage valve for flows from the piston-rod-side working space and from the working space remote from the piston rod.

[0003] To this end, the damping valve arrangement has a total of four non-return valves. These rectify the volume flow from the piston rod-side working space and the working space remote from the piston rod to the backing valve, and ensure the outflow from the backing valve to both working spaces. The non-return valves for the switching flow are located on or within the main stage valve body.

[0004] The rectification of the volume flow of the backing valve is also relevant to the adjustment of the operating characteristics of the entire damping valve arrangement, since the backing valve also acts on the common main-stage valve. Although it is possible to provide pressure-bearing surfaces of different sizes on the main-stage valve for the two inflow directions from the working space, the damping force ratio achievable in the pull / push direction is insufficient for some applications. Summary of the Invention

[0005] The object of the present invention is to provide a damping valve arrangement having a primary valve which is effective in both operating directions of the shock absorber, wherein the damping force ratio is to be increased when the damping valve arrangement changes the inflow.

[0006] This object is achieved in that the primary valve body of the primary valve has a first pressure-bearing surface for the flow from the working space on the piston rod side and a second pressure-bearing surface for the flow from the working space remote from the piston rod.

[0007] The use of different pressure-bearing surfaces at the primary valve ensures a substantial asymmetry of the damping force, which can be easily determined via the area ratio of the two pressure-bearing surfaces.

[0008] Due to the simple basic design of the damping valve arrangement, the first pressure-bearing surface and the second pressure-bearing surface are acted upon jointly by an incoming flow from one of the two working spaces.

[0009] Another measure for achieving asymmetric damping force levels is that the primary valve has a first control chamber for the first pressure-bearing surface and a second control chamber for the second pressure-bearing surface, with the two control chambers being hydraulically separated. Targeted pressure control in the control chambers can additionally influence the operating behavior of the primary valve and, therefore, the mainstage valve.

[0010] Preferably, the primary valve body has a stepped profile, wherein the stepped portion forms the first pressure-bearing surface. For example, the end surface of the primary valve can serve as the second pressure-bearing surface.

[0011] Another measure for simplifying the flow path in the damping valve arrangement is to separate the first control chamber from the second control chamber by a check valve which prevents flow from the first control chamber to the second control chamber.

[0012] In another embodiment, both working spaces have separate flow connections with at least one throttle to the connected control chamber. The two throttle locations preferably have different throttle strengths. A lower throttle strength results in a higher pressure in the control chamber of the primary valve, which in turn increases the opening force acting on the primary valve. This, combined with a reduced hydraulic closing force acting on the main-stage valve, allows for a softer damping force characteristic.

[0013] According to an advantageous dependent claim, the first flow connection from the first working space to the primary valve comprises at least two throttles connected in series, wherein a first throttle of the two throttles is connected to the control line between the primary valve and the main-stage valve. The use of two throttles allows the hydraulic closing force characteristic at the main-stage valve body and the hydraulic opening force characteristic at the primary valve body to be determined separately.

[0014] Another option for determining the damping force characteristic of the damping valve arrangement is to connect the second control chamber to the second working space in an unthrottled manner. Thus, for the same inflow direction, different pressure levels can be provided for the two control chambers, thereby using a different control parameter at the primary valve.

[0015] For incoming flow from the first working space, the lifting behavior of the primary valve can also be influenced by refilling the second control chamber from the second working space through the restriction in the second flow path. The restriction in the second flow path counteracts the lifting force in the first control chamber by reducing the pressure in the second control chamber.

[0016] In an alternative embodiment, the first control chamber is connected to the second control chamber on the outflow side via a supplementary flow channel, wherein the supplementary flow channel has a nonreturn valve that opens toward the second control chamber. This configuration ensures a sufficient supplementary flow into the second control chamber regardless of the connection between the second control chamber and the second working space. Consequently, the pressure conditions in the second working space have no influence on the supplementary flow of damping medium into the second control chamber.

[0017] In another variant, both flow connections have a first throttle for the control line to the main stage valve and a second throttle for the primary valve. This provides a larger adjustment range for the design of the damping valve arrangement.

[0018] On the other hand, both flow connections of the two working spaces to the first control chamber of the primary valve can be connected to a common second throttle in order to simplify the structural design of the damping valve arrangement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described in more detail with reference to the following drawings, wherein:

[0020] Figure 1 A damping valve arrangement is shown having a primary valve with a separate pressure-bearing surface for each incoming flow direction;

[0021] Figure 2 A primary valve is shown, wherein a throttle is provided upstream of the various pressure chambers;

[0022] Figure 3 Shown according to Figure 2 A primary valve having an unrestricted supplementary flow function;

[0023] Figure 4 A primary valve with two throttles connected in series is shown;

[0024] Figure 5 Shown according to Figure 4 A primary valve having an unrestricted supplementary flow function; and

[0025] Figure 6 Shown according to Figure 4 An alternative variant of the primary valve. DETAILED DESCRIPTION

[0026] Figure 1 The hydraulic circuit diagram shows a component of a shock absorber 3 with an adjustable damping valve assembly 1. The damping valve assembly 1 can be connected internally to the shock absorber 3, for example, at the piston rod or as a base valve, or externally via a connecting sleeve or hose connection. The damping valve assembly 1 includes a primary valve 7 that can be actuated by an actuator 5 for hydraulically controlling a main-stage valve 9. At least one return spring 11 preloads the primary valve into a defined initial operating position. The main-stage valve 9 provides hydraulic separation between a first working chamber 13 and a second working chamber 15. The first working chamber 13 interacts with a first annular pressure-bearing surface 19 of a main-stage valve body 21 via a first damping medium passage 17. A second pressure-bearing surface 23 of the main-stage valve body is acted upon via a second damping medium passage 25 of the second working chamber 15. When the main-stage valve 9 is open, the two working chambers 13 and 15 are interconnected via the two damping medium passages 17 and 25. Preferably, the working space 13 is compressed during an extension movement of the shock absorber 3 , whereas the working space 15 is compressed during a compression movement of the shock absorber 3 .

[0027] The damping valve arrangement 1 also includes a check valve assembly for rectifying the control volume flow from the working spaces 13, 15 of the shock absorber 3 to the common primary valve 7. A first check valve 29 is arranged in a first flow connection 27 between the first working space 13 and the primary valve 7. This first check valve opens in the flow direction toward the primary valve 7. A second flow connection 31 between the second working space 15 and the primary valve 7 includes a second check valve 33, which also opens when flow from the second working space 15 is directed toward the primary valve 7. A third check valve 35 and a fourth check valve 37 are arranged in a first discharge line 39 and a second discharge line 41, respectively, from the primary valve 7 to the two working spaces 13, 15. The third check valve 35 and the fourth check valve 37 open when flow from the primary valve 7 is directed toward the two working spaces 13, 15 and close in the opposite flow direction.

[0028] The primary valve body 43 of the primary valve 7 has a first pressure-bearing surface D1 for incoming flow from the first working space 13 and a second pressure-bearing surface D2 for incoming flow only from the second working space 15. The two pressure-bearing surfaces D1 and D2 have different areas. The product of the pressure acting on surfaces D1 and D2 and the areas of the two surfaces represents the lift force acting on the primary valve 7 in relation to the flow direction.

[0029] The primary valve 7 has a first control chamber 45 for the first pressure-bearing surface D1 and a second control chamber 47 for the second pressure-bearing surface D2, the two control chambers being hydraulically separated. For example, the primary valve body 43 has a stepped profile, with the step forming the first pressure-bearing surface D1. The end face of the primary valve body 43 forms the second pressure-bearing surface D2 and a sealing portion for the second control chamber 47.

[0030] For the incoming flow from the first working space 13, only the first pressure surface D1 is loaded through the first flow connection 27, while for the incoming flow from the second working space 15, both the first pressure surface D1 and the second pressure surface D2 are loaded because the second flow connection 31 opens into the connection 49 in the first flow connection 27, and a third flow connection 51 exists between the second working space 15 and the second control chamber 47. The third flow connection 51 can open into the second discharge line 41 or directly into the second working space 15.

[0031] In addition to the two different pressure-bearing surfaces D1, D2 for each incoming flow direction, throttles 53, 55 are used as further regulating options in the first flow connection 27 and the second flow connection 31. The two throttles 53, 55 are respectively arranged between the working spaces 13, 15 and the connection 49 and thus influence the pressure level in the first control chamber 45 of the primary valve 7 and the pressure level in the control chamber 57 of the main-stage valve 9. The figure shows that the check valves 29, 33 can be connected hydraulically in series upstream or downstream of the respective throttles 53, 55 in the flow connections 27, 31 in the flow direction toward the first control chamber 45.

[0032] The first control chamber 45 is coupled via a control line 59 to the connection 49, to which the two flow connections 27, 31 are also coupled, and is also connected to the control chamber 57 of the main-stage valve 9. The pressure level in the first control chamber 45 of the primary valve 7 therefore determines the pressure level in the control chamber 57 of the main-stage valve 9.

[0033] When fluid flows from the first working space 13 into the damping valve arrangement 1, the first pressure-bearing surface 19 on the mainstage valve body 21 is acted upon via the first damping medium channel 17. Furthermore, when the first check valve 29 connected to the throttle 53 opens, the first control chamber 45 of the primary valve 7 is acted upon via the first flow connection 27. Depending on the actuation of the actuator 5, a lifting force is generated, which is determined in particular by the dimensions of the first pressure-bearing surface D1 on the primary valve body 43. The closed second check valve 33 prevents a hydraulic short circuit to the second working space 15.

[0034] The second control chamber 47 , which is enlarged during the lifting movement of the primary valve 7 , can be refilled with damping medium from the second working space 15 via the third flow connection 51 without throttling.

[0035] When flow from the second working space 15 to the damping valve arrangement 1 occurs, it flows through the second damping medium channel 25 in the lifting direction toward the second pressure-bearing surface 23 on the main stage valve body 21. Damping medium flows hydraulically and in parallel through the throttle 55 into the second flow connection 31 and, through the open second check valve 33, via the connection 49, into the first control chamber 45 of the primary valve 7. Simultaneously, the second control chamber 47 of the primary valve 7 is unthrottled via the third flow connection 51. This unthrottled inflow into the second control chamber 47 significantly increases the lifting force of the primary valve 7. Consequently, for the same output pressure in the second working space 15, a significantly greater hydraulic lifting force acts on the primary valve 7. For incoming flow from one of the working spaces 13 or 15, the third and fourth check valves 35 and 37 in the outlet lines 39 and 41 prevent bypassing of the primary valve 7.

[0036] according to Figure 2 The embodiment of the damping valve device 1 is based on Figure 1 The damping valve device 1 of FIG. 1 is different in that, in addition to the first connection 49, the second flow connection 31 also has a second connection 61, which connects the second flow connection 31 to the second control chamber 47 of the primary valve 7 via a bypass connection 63. The second connection 61 is arranged downstream of the throttle 55 in the flow direction toward the second control chamber 47. Therefore, the two control chambers 45, 47 are pressurized in the same way. Figure 1 Compared to the embodiment of FIG1 , for an incoming flow from the second working space 15, at the same excitation of the shock absorber, the damping valve arrangement 1 generates a smaller lifting force at the primary valve 7 due to the pressure drop at the first throttle 55 upstream of the bypass connection 63. Therefore, at the same pressure in the second working space 15, a greater closing force in the control chamber 57 of the main-stage valve 9 tends to be achieved at the main-stage valve 9, and thus an overall greater damping force is achieved at the main-stage valve 9.

[0037] For the incoming flow from the first working space 13, the second control chamber 47 must be filled during the lifting movement by flowing through the throttle 55. Therefore, the lifting movement of the primary valve 7 in this incoming flow direction, in particular after a change in the incoming flow direction, is slowed down or weakened.

[0038] according to Figure 3 The damping valve device 1 is based on Figure 2 In addition, the first control chamber 45 of the primary valve 7 is connected on the outflow side to the second control chamber 47 via a supplementary flow channel 65, wherein the supplementary flow channel 65 has a nonreturn valve 67 that opens in the flow direction toward the second control chamber 47. Therefore, the refilling of the second control chamber 47 is independent of the pressure conditions in the second working space 15 or the throttling effect of the throttle 55 in the second flow connection 31 between the second working space 15 and the second control chamber 47.

[0039] The flow from the second working space 15 around the primary valve 7 is prevented by the non-return valve 67. The damping medium flowing from the first working space 13 into the primary valve 7 flows into the second control chamber 47 of the primary valve 7, but flows out into the second working space 15 via the second outlet line 41 and through the second flow connection 31, because the throttle 55 in the second flow connection 31 presents a flow resistance that is greater than the line-related flow resistance in the second outlet line 41.

[0040] according to Figure 4 The damping valve device 1 has at least two throttles 53, 69 connected hydraulically in series in the first flow connection 27 from the first working space 13 to the primary valve 7, wherein the two throttles 53, 69 are connected to the control line 59 between the primary valve 7 and the main stage valve 9. The basic principle of the damping valve device 1 is similar to that according to Figure 1The second throttle 69 further reduces the pressure level in the first control chamber 45 compared to the second control chamber 47 in the primary valve 7. Simultaneously, by using the first of the two throttles 53 and 69, the pressure level in the control chamber 57 of the main-stage valve 9 can be predetermined in relation to the compression of the working spaces 13 and 15. If the first throttle 53 exerts a lesser throttling effect, a higher closing pressure will build up in the control chamber 57 of the main-stage valve 9, and vice versa. The second throttle 69 influences the pressure in the first control chamber 45 so that the lifting force acting on the primary valve 7 matches the predetermined damping force characteristic of the damping valve arrangement 1. The throttle 53 that acts first in the flow direction from the first working space 13 primarily determines the closing force trend in the control chamber 57 of the main stage valve 9, and the second throttle 69 determines the pressure in the first control chamber 45 of the primary valve 7 at which the required lifting force is achieved at the primary valve 7, in order to thereby adjust the damping force that can be generated by the main stage valve 9. Figure 1 As shown, the second control chamber 47 is refilled unthrottled from the second working space 15 via the third flow connection 51 .

[0041] In accordance with Figure 5 The embodiment of the damping valve device 1 basically has Figure 4 The difference is that, if combined Figure 3 As described, the supplementary filling passage 65 is used in conjunction with the check valve 67 .

[0042] Figure 4 The two flow connections 27, 31 are shown, each with a first throttle 53, 55 for the control line 59 to the main stage valve 9, and with a common second throttle 69 for the primary valve 7. Figure 5 In the embodiment, the two flow connections 27, 31 from the two working spaces 13, 15 to the first control chamber 45 of the primary valve 7 are likewise connected to a common second throttle 69. However, the second control chamber 47 of the primary valve 7 is additionally connected downstream of the throttle 55 in the second flow connection 31 and is therefore connected to the control chamber 45 according to FIG. Figure 4 Therefore, in the damping valve device 1, for the incoming flow from the second working space 15, the two control chambers 45, 47 are subjected to a reduced control pressure. Figure 4 Compared with the embodiment of the present invention, the lifting force at the primary valve 7 is further reduced, and the damping force characteristic tends to change slightly in the direction of higher damping force. Here, the supplementary flow channel 65 is also used in conjunction with the check valve 67.

[0043] according to Figure 6The damping valve arrangement 1 includes a first flow connection 27 connected in series with two throttles 53 and 69 located between the first working space 13 and the first control chamber 45 of the primary valve 7. A first connection 49, connecting the first flow connection 27 to the control line 57 leading to the main-stage valve 9, is located downstream of the first throttle 53 in the direction of flow from the first working space 13. A second throttle 69 follows in the direction of flow toward the first control chamber 45 of the primary valve 7 to further reduce the control pressure in the first control chamber 45. A second connection 61, connecting the second flow connection 31 to the first control chamber 45 of the primary valve 7, is located between the second throttle 69 and the first control chamber 45. Consequently, damping medium from the second working space 15 flows only through the one throttle 31, the open second check valve 33, and the second connection 61 before reaching the first control chamber 45 of the primary valve 7. Therefore, in this flow direction, the pressure level in the first control chamber 45 is higher than in the case of an inflow from the first working space 13 through the two throttles 53, 69 connected in series. Figure 1 As shown, it is directly affected by the second working space 15. In this variant, the difference in the damping force that can be achieved between the two flow directions of the damping valve device is significantly greater than that according to Figure 5 A variation of the damping valve device 1 .

[0044] Reference Signs List

[0045] 1 Damping valve device

[0046] 3 shock absorbers

[0047] 5 Actuator

[0048] 7 Primary valve

[0049] 9 Main stage valve

[0050] 11 Return spring

[0051] 13 First Workspace

[0052] 15 Second Workspace

[0053] 17 First damping medium channel

[0054] 19 First pressure-bearing surface at the main stage valve

[0055] 21 Main stage valve body

[0056] 23 Second pressure-bearing surface at the main stage valve

[0057] 25 Second damping medium channel

[0058] 27 First flow connection

[0059] 29 Check valve in first flow connection

[0060] 31 Second flow connection

[0061] 33 Check valve in the second flow connection

[0062] 35 Check valve

[0063] 37 Check valve

[0064] 39 discharge line

[0065] 41 Discharge line

[0066] 43 Primary valve body

[0067] 45 Primary control chamber of primary valve

[0068] 47 Secondary control chamber of primary valve

[0069] 49 connection part

[0070] 51 Third flow connection

[0071] 53 Throttling Unit

[0072] 55 Throttle

[0073] 57 Main stage valve control room

[0074] 59 Control line between main valve and primary valve

[0075] D1 First pressure-bearing surface

[0076] D2 Second pressure surface

[0077] 61 Second connecting portion

[0078] 63 Bypass connection

[0079] 65 Supplementary flow channel

[0080] 67 Check valve in the supplementary flow channel

[0081] 69 Throttling Department.

Claims

1. An adjustable damping valve arrangement (1) for a shock absorber (3), comprising a primary valve (7) for hydraulically controlling a main stage valve (9), wherein: The damping valve device (1) has a check valve assembly (73) for rectifying a control volume flow from the working space (13, 15) of the shock absorber (3) to the primary valve (7), characterized in that the primary valve body (43) of the primary valve (7) has a first pressure-bearing surface (D1) for an incoming flow from the first working space (13) and a second pressure-bearing surface (D2) for an incoming flow from the second working space (15).

2. The adjustable damping valve device (1) according to claim 1, characterized in that: For an incoming flow from one of the two working spaces (15), the first pressure-bearing surface (D1) and the second pressure-bearing surface (D2) are loaded.

3. The adjustable damping valve device (1) according to claim 1 or 2, characterized in that: The primary valve (7) has a first control chamber (45) for the first pressure-bearing surface (D1) and a second control chamber (47) for the second pressure-bearing surface (D2), the first control chamber and the second control chamber being hydraulically separated.

4. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 3, characterized in that The primary valve body (43) has a stepped profile, wherein the stepped portion forms the first pressure-bearing surface (D1).

5. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 4, characterized in that Both working spaces (13, 15) have a separate flow connection (27, 31) with at least one throttle point (53, 55) leading to a connected control chamber (45, 47).

6. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 5, characterized in that A first flow connection (27) from the first working space (13) to the primary valve (7) has at least two throttles (53, 69) connected in series, wherein a first throttle (53) of the two throttles (53, 69) is connected to a control line (59) between the primary valve (7) and the main stage valve (9).

7. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 6, characterized in that The second control chamber (47) is connected to the second working space (15) in an unthrottled manner.

8. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 6, characterized in that The second control chamber (47) is refilled from the second working space (15) through the throttle portion (55) of the second flow path (31).

9. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 8, characterized in that Both flow connections (27, 31) have a first throttle (53, 55) for a control line (59) to the main stage valve (9) and a second throttle (69) for the primary valve.

10. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 9, characterized in that The two flow connections (27, 31) of the two working spaces (13, 15) to the first control chamber (45) of the primary valve (7) are both connected to a common second throttle (69).

11. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 10, characterized in that The first control chamber (45) is connected to the second control chamber (47) on the outflow side via a supplementary flow channel (65), wherein the supplementary flow channel (65) has a nonreturn valve (67) which opens in the direction of the second control chamber (47).

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