Adjustable damping valve device for a vibration damper

Abstract

Adjustable damping valve device for a vibration damper, with a pre-stage valve for the hydraulic control of a main stage valve, wherein the pre-stage valve is connected to a piston rod-side and a piston rod-remote working chamber of a working cylinder of the vibration damper, wherein a check valve arrangement with at least two check valves for rectifying a control volume flow from the working chambers of the working cylinder to the pre-stage valve is arranged on a main stage valve body of the main stage valve, wherein the main stage valve body has at least one first throttle channel with a first check valve disc on a larger pitch circle and a second throttle channel with a second check valve disc on a smaller pitch circle, wherein both check valves are connected in the opening direction to a control chamber for the main stage valve body.

Description

[0001] The invention relates to an adjustable damping valve device for a vibration damper according to the preamble of patent claim 1.

[0002] DE 44 18 972 A1 relates to an adjustable damping valve device comprising a valve housing on a piston rod of a vibration damper. The functional advantage of this damping valve device lies in the use of a single pre-stage valve for controlling a main-stage valve with an inflow originating from a working chamber on the piston rod side and from a working chamber remote from the piston rod.

[0003] For this purpose, the damping valve assembly features a total of four check valves that ensure the equalization of the flow from the piston rod-side and the piston rod-remote working chambers to the pilot valve and the discharge from the rear chamber of the pilot valve to the two working chambers. The check valves that control the flow are located on or in the main stage valve body.

[0004] The arrangement of the check valves within the damping valve device is very difficult due to the limited installation space and the complexity of the flow paths.

[0005] The generic DE 692 03 374 T2 discloses a damping valve device with four check valves. Two check valves are connected to a common control chamber. However, here too, the flow paths to the pre-stage valve are complex and limited in terms of flow cross-section.

[0006] DE 38 27 255 A1 relates to an adjustable damping valve device in which the volume flow for a main stage valve is also rectified by concentrically arranged check valves, whereby a volume flow for a pre-stage valve is forwarded from the rectified main stage valve flow.

[0007] DE 40 16 807 A1 describes an adjustable damping valve device that has two check valves for equalizing a volume flow in the flow direction to a pre-stage valve. The two check valves are designed as disk valves and are positioned axially one above the other with a gap between them.

[0008] The object of the present invention is to provide a damping valve device with a compact check valve arrangement.

[0009] The problem is solved by the features of patent claim 1.

[0010] Due to the radial arrangement of the two check valves relative to each other, separate throttle channels are available, each of which can have different throttle characteristics. Furthermore, the channel layout is simple, and an existing control chamber can be used to guide fluid to the pre-stage valve. In a further advantageous embodiment, a check valve disc of one check valve acts as a stop for the check valve disc of the other check valve. This simplifies the design of the check valve arrangement.

[0011] According to an advantageous subclaim, a radially outer and a radially inner valve seat surface for each of the check valve discs form an annular groove into which at least one throttle channel of the check valve opens. In particular, the check valve disc forming the stop is stably mounted by its support on the valve seat surfaces and is protected from one-sided tilting. Furthermore, the diameter of the throttle channel has no influence on the size of the pressurized area on the check valve disc.

[0012] Furthermore, the valve seat surfaces of one annular groove are axially offset from the valve seat surfaces of the other annular groove. The clearance required for the lift path of one check valve disc is not achieved by complex valve assembly of the check valve forming the stop, but simply by the axial offset.

[0013] A further measure with regard to a simple structural design of the check valve arrangement is that the check valve disc forming the stop has a profile on the edge which, when axially overlapping with the other check valve disc in its stop position, provides a passage cross-section between the throttle channel of the open check valve and the control chamber of the main stage valve.

[0014] In a further advantageous embodiment, the profile of the check disc represents a guide profile for the check valve disc on the main stage valve body. The combination of the two functions of guidance and the formation of a passage cross-section results in an optimal surface distribution of the functions on the check valve disc. This creates a large annular sealing area and a comparatively large profile area, which, among other things, leads to a certain advantageous elasticity of the check valve disc.

[0015] Preferably, both check valve discs are centered on a guide pin of the main stage valve body. Only one common guide area is required, so this measure also promotes the simple design of the damping valve device.

[0016] The main stage valve body features an axial stop to limit the lift of the check valve disc. Especially when the profiled section is combined with a guide ring groove in the main stage valve body, the check valve disc, which acts as a stop, can be easily installed, and no additional components, such as a retaining ring for axially securing the check valve disc, are required.

[0017] Preferably, the axial stop is formed by the guide pin of the main stage valve body.

[0018] The invention will be explained in more detail with reference to the following description of the figures.

[0019] It shows: Fig. 1 Section through the damping valve device Fig. 2 Excerpt from Fig. 1 in the area of main stage valve-pre-stage valve Fig. 3 Detailed view in the area of the main stage valve Fig. 4 Check valve disc according to Fig. 1 - 3 as individual parts Fig. 5 Alternative version to the variant according to Fig. 2 - 4

[0020] The Fig. Figure 1 shows a section through an adjustable damping valve device 1 for a vibration damper 3. In this exemplary embodiment, the damping valve device 1 is shown in a damping valve housing 5 on an axially movable piston rod 7 within the working cylinder 9 of the vibration damper 1. However, the damping valve housing 5 and thus also the damping valve device 1 can also be arranged spatially outside the vibration damper 1 and connected hydraulically, for example, via a pipe or hose connection.

[0021] The damping valve device 1 comprises an electromagnetic actuator 11 with a solenoid coil 13 and an armature 15, which acts on the end of a pre-stage valve body 17 of a pre-stage valve 19. The force of the solenoid coil 13 counteracts at least one return spring 21.

[0022] The pre-stage valve 19 serves to hydraulically control a main stage valve 23, via which a piston rod-side working chamber 25 and a piston rod-remote working chamber 27 are connected to each other within the working cylinder 9. The Fig. 1 shows radial connection channels 29 within a valve housing ring 31 as a component of the damping valve housing 5, which connect the working chamber 25 on the piston rod side with the main stage valve 23. A passive damping valve 33; 35 is arranged between the working chamber 27 remote from the piston rod and the main stage valve 23, each for a flow direction of the damping valve device 1. The two passive damping valves 33; 35 are used optionally. Regardless of the working direction of the piston rod 7 within the vibration damper 3, the volume flow of the damping medium located in the working cylinder 9, which determines the damping force, is displaced via the connection channels 29, the main stage valve 23 and the two passive damping valves 33; 35. Otherwise, a sealed piston 36 as a functional section of the damping valve housing 5 ensures a spatial separation of the two working chambers 25; 27.

[0023] The main stage valve 23 comprises a main stage valve body 37 and a main stage valve seat surface 39 (see Fig. 2), which is formed by a valve ring 41 within the valve housing ring 31.

[0024] The main stage valve body 37 is guided for axial displacement within a step opening 43 of the valve housing ring 31. The main stage valve body 37 is sealed to an inner circumferential surface 43A of the step opening 43. The main stage valve body 37, a portion of the circumferential surface 43A, and a bottom 43B of the step opening 43 form a control chamber 45 for the main stage valve 23. This control chamber 45 is connected to the radial connecting channels 29 via at least one first throttle channel 47 on a larger pitch circle, wherein, due to the throttling function of the throttle channel 47, a pressure drop exists between the pressure in the connecting channels 29 and the control chamber 45. The pressure in the control chamber 45 exerts a compressive force on the main stage valve body 37, which acts as a closing force for the main stage valve 23.

[0025] The throttle channel 47 is covered by a first check valve disc 67. On a smaller pitch circle, the main stage valve body 37 has a second throttle channel 61 with a second check valve disc 69, with both check valves 47; 67 and 61; 69 being connected to the control chamber 45 in the opening direction. The second throttle channel 61 is connected to a connection chamber 65, which in turn is connected to the piston rod-side working chamber 27 via the two passive damping valves. The main function of the two check valves 47; 67 and 61; 69 is to prevent a hydraulic short circuit between the two working chambers 27; 29 via the control chamber 45 of the main stage valve 23.

[0026] The main stage valve body 37 has a guide pin 49 pointing in the direction of the pilot valve 19, which has a pilot valve seat surface 51 at its end for the plate-shaped pilot valve body 17. The guide pin 49 is hollow and has at least one radial connection opening 53 to an axial channel in which the same pressure is present as in the first control chamber 45. The radial connection opening can also be designed as a second throttle within a series circuit with the throttle channels 47; 61.

[0027] The axial channel forms a second control chamber 55 for the main stage valve with a second closing force on the main stage valve body 37. For the pre-stage valve 19, the axial channel represents a control chamber 57 with a pressure force component in the lift direction of the pre-stage valve 19.

[0028] The damping medium displaced by the pilot valve 19 reaches a return chamber 71 of the pilot valve 19 between the bottom 43B of the valve housing ring 31 and the actuator 11, which is connected to a check valve arrangement 73 comprising a check valve ring 75 which is equipped on both sides with at least one check valve disc 77; 79. The check valve ring 75 is a separate and replaceable component from the valve housing ring 31. The check valve discs 77; 79 on both sides in combination with the check valve ring 75 form two check valves 81; 83 for controlling the control volume outflow from the pilot valve 19 into the two working chambers 25; 27 of the working cylinder 9. In the flow direction starting from the check valve arrangement 73 in the direction of the piston rod-side working chamber 25, the damping valve housing 5 has at least one radial connecting opening 85 in this example.For connecting the pre-stage valve 19 to the working chamber 27 remote from the piston rod, the valve housing ring 31 has a channel system 87 that opens into the connection chamber 65. When the check valve arrangement 73 is approached by flow from one of the two working chambers 25; 27, the check valve 81; 83, which is approached directly, i.e., bypassing the pre-stage valve 19, is closed.

[0029] The check valve ring 75 is centered on the valve housing ring 31 via its central through-opening 89. The check valve ring 75 has an angled channel 91 in the direction of the rear chamber 71, which in turn includes axial connection openings 93 to the channel system 87 in the valve housing ring 31.

[0030] The overview of the Fig. 2 to 4 illustrate the structural design of the check valves 47; 67 and 61; 69.

[0031] A radially outer and a radially inner valve seat surface 95; 97; 101; 103 for each of the check valve discs 67; 69 form an annular groove 99; 105, into which the at least one throttle channel 47; 61 of the check valve opens. The valve seat surfaces 95; 97 of one annular groove have an axial offset 107 from the valve seat surfaces 101; 103 of the other annular groove.

[0032] The larger-diameter check valve disc 67 of one check valve acts as a stop for the smaller-diameter check valve disc 69 of the other check valve. The axial offset 107 between the annular grooves 99; 105 and the valve seat surfaces creates the necessary clearance for the lift-off movement of the check valve disc 69 when the check valve 47; 67 is closed. In principle, this clearance could also be achieved by equipping the check valve 47, 67 with a different valve disc configuration, but this would involve significantly greater assembly effort.

[0033] The check valve disc 67 forming the stop has a profile 109 on its edge, here on the inner diameter, which, when axially overlapping with the other check valve disc 69 in its stop position, provides a passage cross-section 111 between the throttle channel 69 of the open check valve and the control chamber 45 of the main stage valve 23. The profile 109 is formed by elastic fingers 113, each of which defines T-grooves whose greatest radial extent is larger than the outer diameter of the check valve disc 69.

[0034] The profiling 109 of the check disc 67 represents a guide profile 115 of the check valve disc 67 on the main stage valve body 37, in which the inner diameter of the guide profile 115 is adapted to a guide section 117 of the guide pin 49. ( Fig. 3) The guide profile 115 forms a clearance fit with the guide section 117, which guarantees a low displacement force for the movement of the check valve disc 67 on the guide pin 49.

[0035] In the present example, both check valve discs 67; 69 are centered on the guide pin 49 of the main stage valve body. The guide diameter on the guide section 117 for the check valve disc 69 is slightly larger than the guide diameter for the check valve disc 67. The reason for this is that the main stage valve body 37 has an axial stop 119 for limiting the lift of the check valve disc 67, which is formed by the guide pin 49 of the main stage valve body. For this purpose, the guide pin has an annular groove 121 for receiving the profiling 109 of the check valve disc 67. Axially above the annular groove 121, the guide pin 49 has a short conical profile 123, which slightly widens the inner diameter of the profiling 109 during the assembly movement of the check valve disc 67, so that a groove side surface of the annular groove 121 can form the axial stop 119 for the check valve disc.

[0036] The execution according to Fig. 5 describes a comparison to the Fig.1 to 3 very similar, but not inventive, damping valve device 1. Deviating from this, the check valve arrangement for the check valve discs 61; 69 of the throttle channels 47; 67 has a separate stop disc 125, which is arranged on the guide pin 47 of the main stage valve body 37. The check valve discs 67; 69 are designed as simple annular discs without profiling, wherein the larger check valve disc 67 is centered on an annular wall 37R of the main stage valve body 37 and the smaller valve disc on the guide pin 47. Two closing springs 127; 129 ensure a defined position of the check valve discs 67; 69, e.g. when the damping medium flow is at rest within the damping valve device 1. Here too, the valve discs 67; 69 rest on valve seat surfaces 95; 97; 101; 103, so that an overpressure in the control chamber 45 always supports the check valve disc currently resting on the valve seat surfaces in its closing function.The stop disc 125 has, for example, openings 131 running in the circumferential direction, which ensure the connection between the control chamber 45 and the connection opening when the check valve discs 67; 69 are in the stop position.

[0037] Regardless of the design of the check valves 47; 67; 61; 69, the damping medium passes through the passive damping valve 35 when flowing towards the damping valve device 1, starting from a compression of the working chamber 27 remote from the piston rod, and ensures, within the connection chamber 65, a pressurization of the main stage valve body 37 within a pressurization area delimited by the main stage valve seat surface 39.

[0038] A hydraulic closing force is exerted on the main stage valve body 37 via the pressures in the two control chambers 45; 55. The control volume flow flows via the pre-stage valve 19 and the check valve disc 77, which is lifted from the check valve ring 75, through the connecting opening 85 into the piston rod-side working chamber 27.

[0039] The damping medium acting on the check valve 83 via the channel system 87 in the valve housing ring 31 closes this check valve 83. The check valve 67 in the main stage valve body 37 is also closed in this flow situation of the damping valve device 1.

[0040] When the damping valve device 1 flows from the piston rod-side working chamber 25, the displaced damping medium is applied to an annular surface of the main stage valve body 37, which extends radially outside the main stage valve seat surface 39 of the main stage valve 23 and inside the outer surface 43A of the valve housing ring 31. This pressure force likewise causes a lifting force on the main stage valve body 37. In parallel, the first control chamber 45 of the main stage valve 23 is also pressurized hydraulically via the first throttle channel 47, whereupon a pressure increase also occurs in the second control chamber 55 of the main stage valve 23, which, together with the pressure increase in the first control chamber 45, causes a closing force on the main stage valve body 37.

[0041] The control volume flow flowing through the pilot valve 19 into the return chamber 71 then also reaches the connection channel 101, passes through the at least one radial channel 99 into the angle channel 91 and can then flow through the connection openings 93 in combination with the channel system 87 into the connection chamber 65 and then further through the passive damping valve 35 into the working chamber 27 remote from the piston rod. Here, too, the check valve 81 is closed in the direction of the piston rod-side working chamber 25 by the opposite flow from the piston rod-side working chamber 25, so that the use of the total of four check valves 67; 69; 81; 83 achieves a rectification of the control volume flow through the pilot valve 19. Reference symbol 1 Adjustable damping valve device 3 vibration dampers 5 Damping valve housing 7 Piston rod 9 working cylinders 11 Actuator 13 Solenoid coil 15 anchors 17 Pre-stage valve body 19 Pre-stage valve 21 Return spring 23 Main stage valve 25 piston rod side working space 27 Working space remote from the piston rod 29 radial connection channel 31 Valve housing ring 33 passive damping valve 35 passive damping valve 36 pistons 37 Main stage valve body 37R Ring wall of the main stage valve body 39 Main stage valve seat surface 41 Valve ring 43 Step opening of the valve housing ring 43A Shell surface of the step opening 43B Bottom of the step opening 45 first control room 47 first throttle channel 49 guide pins 51 Pre-stage valve seat surface 53 Connection opening 55 second control chamber of the main stage valve 57 Control chamber of the pre-stage valve 61 second throttle channel 65 Connection compartment 67 Check valve disc 69 Check valve disc 71 backcourt 73 Check valve arrangement 75 Check valve ring 77 Check valve disc 79 Check valve disc 81 Check valve 83 Check valve 85 connection opening 87 canal system 89 Passage opening 91 Angle channel 93 Connection opening 95 outer valve seat surface 97 inner valve seat surface 99 Ringgraben 101 outer valve seat surface 103 inner valve seat surface 105 Ringgraben 107 axial offset 109 Profiling 111 Passage cross-section 113 fingers 115 Leadership Profile 117 Guide Section 119 Axial stop 121 Ring groove 123 conical profile 125 stop disc 127 closing spring 129 closing spring 131 Opening in stop disc

Claims

[1] Adjustable damping valve device (1) for a vibration damper (3), with a pre-stage valve (19) for hydraulically controlling a main-stage valve (23), wherein the pre-stage valve (19) is connected to a piston rod-side and a piston rod-remote working chamber (25; 27) of a working cylinder (9) of the vibration damper (3), wherein at least two check valves (47; 67; 61; 69) are arranged on a main-stage valve body (37) of the main-stage valve (23) for rectifying a control volume flow from the working chambers (25; 27) of the working cylinder (9) to the pre-stage valve (19), wherein the main-stage valve body (37) has at least one first throttle channel (47) with a first check valve disc (67) on a larger pitch circle and a second throttle channel (61) with a second check valve disc (69) on a smaller pitch circle, wherein both check valves (47; 67; 61;69) are connected in the opening direction to a control chamber (45) for the main stage valve body (37) and the check valve disc (67) of one check valve performs a stop function for the check valve disc (69) of the other check valve.; [2] Adjustable damping valve device (1) according to claim 1, characterized by in that a radially outer and a radially inner valve seat surface (95; 97; 101; 103) for one of the check valve discs (67; 69) form an annular groove (99; 105) into which the at least one throttle channel (47; 61) of the check valve opens. [3] Adjustable damping valve device (1) according to claim 2, characterized by that the valve seat surfaces (95; 97) of one annular trench (99) have an axial offset to the valve seat surfaces (101; 103) of the other annular trench (105). [4] Adjustable damping valve device (1) according to one of claims 1 to 3, characterized bythat the check valve disc (67) forming the stop has a profiling (109) on the edge side which, when axially overlapping with the other check valve disc (69) in its stop position, provides a passage cross-section (111) between the throttle channel (61) of the open check valve (61; 69) and the control chamber (45) of the main stage valve (23). [5] Adjustable damping valve device (1) according to claim 4, characterized by that the profiling (119) of the check valve disc represents a guide profile of the check valve disc on the main stage valve body. [6] Adjustable damping valve device (1) according to claim 5, characterized by that both check valve discs (67; 69) are centered on a guide pin (47) of the main stage valve body (37). [7] Adjustable damping valve device (1) according to claim 5, characterized bythat the main stage valve body (37) has an axial stop (119) for limiting the stroke of the check valve disc (67). [8] Adjustable damping valve device (1) according to claim 6 or 7, characterized by that the axial stop (119) is formed by the guide pin (49) of the main stage valve body (37).

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