Adjustable damping valve device for an adjustable vibration damper

Abstract

Adjustable damping valve device (1) for a vibration damper (3), wherein the damping valve device (1) 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 (1), wherein the damping valve device (1) comprises a main stage valve (23) and a pre-stage valve (19) hydraulically controlling the main stage valve (23), wherein the pre-stage valve (19) has a control chamber (61) whose pressure level is influenced by a throttle cross-section of the pre-stage valve (19), wherein a pre-stage valve body (17) has a pressurized area in the stroke direction of the pre-stage valve body which, in the event of an inflow from both the piston rod-remote and the piston rod-side working chamber (25;27) in conjunction with the pressure in the control chamber (61) generates a lifting force, characterized in that the pre-stage valve (19) has an additional second pressurized surface (105) effective in the closing direction of the pre-stage valve for an inflow from one of the two working chambers (25; 27), wherein the second pressurized surface (105) interacts with a second control chamber (107) of the pre-stage valve (19).

Description

The invention relates to an adjustable damping valve device for an adjustable vibration damper according to the preamble of claim 1. DE 10 2008 041 735 B3 describes a damping valve device for an adjustable vibration damper, in which a main stage valve is hydraulically controlled by a pre-stage valve by adjusting the pressure level of at least one control chamber, connected to the rear of a main stage valve body, via the pre-stage valve. The pressure force in the control chamber exerts a hydraulic closing force on the main stage valve body. Previously, the design and dimensioning of such a damping valve device involved setting the areas of the main stage valve pressurized in the opening direction and those pressurized in the closing direction to a specific area ratio. Further parameters included the cross-section of the pressurized area in the stroke direction of the pre-stage valve and the closing force of a closing spring for the pre-stage valve. Additionally, the flow rates between the working chambers and the control chamber can also be varied. DE 41 08 471 A1 discloses a damping valve assembly with a pre-stage valve whose conical valve body is connected to a first control chamber. This first control chamber is supplied with flow via an access throttle through several check valves, independent of the operating direction of the vibration damper. In the outflow direction, the pre-stage valve body has a second annular pressurized surface, which is also subjected to the same load regardless of the operating movement. The second control chamber is connected to a rear side of the pre-stage valve body via a pressure equalization channel. This pressure equalization channel serves to hydraulically connect a back chamber of the pre-stage valve to the flow channels of the damping valve assembly, thus preventing the pre-stage valve from being hydraulically blocked. DE 40 16 807 C2 also discloses an adjustable damping valve device with several check valves for equalizing a volume flow through a pre-stage valve. Here too, the pre-stage valve is subjected to the same flow direction regardless of the operating direction. The same applies to DE 10 2015 218 292 A1. The object of the present invention is to provide a further usable setting parameter for a damping valve device. The problem is solved according to the invention by the features of claim 1. When the flow originates from one working chamber, the pre-stage valve is pressurized on a pressurized surface in the downstroke direction and, with the same flow direction, on a pressurized surface in the closing direction. However, when the flow originates from a different working chamber of the vibration damper, only a pressurized surface in the downstroke direction of the pre-stage valve is used. This asymmetry of the pressurized surfaces offers the advantage that, for example, the comfort setting is enhanced during compression of the vibration damper compared to so-called rebound damping, where the piston rod extends from the working cylinder, without compromising driving safety. Utilizing the pressurized surfaces on the pre-stage valve allows for a comparatively compact main stage valve. In a further advantageous embodiment, the second pressurized surface interacts with a second control chamber of the pre-stage valve. The separate control chamber within the damping valve assembly isolates those areas within the damping valve assembly that are not intended to, or do not need to, perform a hydraulic function for the pre-stage valve. To prevent the pre-stage valve from shutting down under extreme flow conditions, the second control chamber is operatively connected to a pressure relief valve. This limits the closing force component to the pre-stage valve. The opening point of the pressure relief valve can also be used as a tuning parameter to adapt the damping valve assembly, and thus the vibration damper, to a specific vehicle. With a view to a simple constructive implementation of the invention, the pre-stage valve body has a guide pin, wherein the guide pin carries the second pressurized surface. The guide pin of the pre-stage valve body engages in a through-opening of a partition within the damping valve assembly, and the second control chamber is at least partially formed by the partition. In addition, the partition wall separates a hydraulic space containing the pre-stage valve and the main stage valve from an actuator space of a valve housing of the damping valve assembly, thus forming an intermediate floor of the valve housing. For another function, the partition includes a channel system that connects one working chamber of the working cylinder with the second pressure chamber. The partition can be designed as a simple, relatively flat annular disc. The pressure relief valve is connected to the duct system. Consequently, the control chamber can be dimensioned independently of the design of the pressure relief valve. Furthermore, the partition is advantageously a functional component of the pressure relief valve. Consequently, the upstream valve can be geometrically optimized for the function of controlling the main stage valve. According to an advantageous dependent claim, a check valve disc of the pressure relief valve is supported against a valve seat surface of the partition. The pressure relief valve is designed as a poppet valve and therefore requires only a small axial installation space. The invention will be explained in more detail using the following description of the figures. It shows: Fig. 1 Longitudinal section through the adjustable damping valve assembly Fig. 2 Detail view in the area of ​​the pre-stage valve according to Fig. 1 Fig. 1 shows a section through an adjustable damping valve assembly 1 for a vibration damper 3. In this embodiment, the damping valve assembly 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 assembly 1, can also be arranged spatially outside the vibration damper 1 and, for example, hydraulically connected via a pipe or hose connection. The damping valve assembly 1 comprises an electromagnetic actuator 11 with a solenoid coil 13 and an armature 15, which acts at its end on a pre-stage valve body 17 of a pre-stage valve 19. The force of the solenoid coil 13 acts against at least one return spring 21. The pre-stage valve 19 serves for the hydraulic actuation of a main stage valve 23, via which a piston rod-side working chamber 25 and a working chamber 27 remote from the piston rod are connected within the working cylinder 9. Fig. 1 shows radial connection channels 29 within a valve housing ring 31 as part of the damping valve housing 5, which connect the piston rod-side working chamber 25 to 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 one flow direction of the damping valve assembly 1. The two passive damping valves 33; 35 are used optionally.Regardless of the direction of operation of the piston rod 7 within the vibration damper 3, the volume flow rate of the damping medium located in the working cylinder 9, which determines the damping force, is displaced via the connecting channels 29, the main stage valve 23, and the two passive damping valves 33 and 35. A sealed piston 36, as a functional section of the damping valve housing 5, ensures spatial separation of the two working chambers 25 and 27. The main stage valve 23 comprises a main stage valve body 37 and a main stage valve seat surface 39, which is formed by a valve ring 41 within the valve housing ring 31. The main stage valve body 37 is guided axially displaceably within a stage opening 43 of the valve housing ring 31 and, together with the stage opening of the valve housing, forms a first control chamber 45. This first control chamber 45 is connected to the radial connection channels 29 via at least one first throttle channel 47, whereby, due to the throttling function of the throttle channel 47, a pressure drop exists between the pressure in the connection channels 29 and the first control chamber 45. The main stage valve body 37 has a valve stem 49 pointing towards the pre-stage valve 19, which has a pre-stage valve seat surface 51 at its end for the pre-stage valve body 17. (Fig. 2) The valve stem 49 is hollow and has at least one radial connection opening 53 to an axial channel 55 as part of the first control chamber 45, which, in the flow direction towards the pre-stage valve 19, has a second throttle channel 59 within an intermediate wall 57, which connects the first control chamber 45 with a second control chamber 61 between the intermediate wall 57 and the pre-stage valve 19 and provides for a further pressure drop between the first control chamber 45 and the second control chamber 61. Within the main stage valve body 37, at least one axial channel 63 with a throttling function similar to the first throttle channel 47 runs, connecting a connection chamber 65 of the damping valve assembly 1 to the first control chamber 45. Both the first throttle channel 47 and the axial channel 63 between the connection chamber 65 and the first control chamber 45 are equipped with a check valve 67; 69, which opens in the inflow direction into the first control chamber 45. This prevents a hydraulic short circuit of the pre-stage valve 19 via the first control chamber 45. The stroke of the pre-stage valve body 17 from the pre-stage valve seat surface 51 defines a throttle cross-section between the pre-stage valve body 17 and the pre-stage valve seat surface 51, which in turn determines the pressure level in both the first and second control chambers 45; 61. The pressures in the two control chambers 45; 61, multiplied by the axially pressurized areas on the main stage valve body 37, yield a closing force acting on the main stage valve body 37, which, for a given operating movement of the vibration damper 3, determines the damping force of the vibration damper 3. The damping medium passing through the pre-stage valve 19 reaches a return chamber 71 of the pre-stage valve 19 between the base of the valve housing ring 31 and the actuator 11, which is connected to a check valve assembly 73 comprising a check valve ring 75 fitted on both sides with at least one check valve disc 77; 79 (Fig. 2). 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 pre-stage valve 19 into the two working chambers 25; 27 of the working cylinder 9. In the direction of flow 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 the connection of the pre-stage valve 19 with the working chamber 27 located away 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 assembly 73 is approached by flow from one of the two working chambers 25; 27, the check valve 81; 83, which is directly approached by flow, i.e., bypassing the pre-stage valve 19, is closed. The check valve ring 75 centers itself on the valve housing ring 31 via its central through-hole 89. As shown in Fig. 2, the check valve ring 75 has an annular groove 91 in the direction of the return chamber 71, which in turn includes axial connection openings 93 to the channel system 87 in the valve housing ring 31. The annular groove 91 is radially bounded by two annular support surfaces 95; 97 for the check valve disc 77. An inner support surface 97 is interrupted by at least one radial channel 99, which connects the annular groove 91 to a radially inner connection channel 101. The connection channel 101 is directly connected to the return chamber 71 of the pre-stage valve 19. The lifting movement of the check valve disc 79 for the channel system 87 in the valve housing ring 31 is limited by the valve housing ring 31. A partition 103 serves to restrict the lifting movement of the check valve disc 77 on the upper side of the check valve ring 75 and additionally fixes the check valve ring 75 axially within the damping valve housing 5. In addition to a pressurized surface of the pre-stage valve 19 or the pre-stage valve body 17, effective in the downstroke direction and framed by the pre-stage valve seat surface 51, the pre-stage valve 19 has a second pressurized surface 105, effective in the closing direction of the pre-stage valve 19, for flow from the piston rod-side working chamber 25. The second pressurized surface 105 interacts with a second control chamber 107 of the pre-stage valve 19. The pre-stage valve body 17 has a guide pin 109 facing the actuator 11, which supports the annular, second pressurized surface 105. The second pressurized surface 105 is formed by a circumferential shoulder of the guide pin 109. The guide pin 109 of the pre-stage valve body 19 engages in a through-opening 11 of the partition 105 fixed to the valve housing 5 within the damping valve assembly 1, the second control chamber 105 being at least partially formed by the partition 103. The through-opening 111 within the partition 103 has a step that forms a bottom 113 of the second pressure chamber 105. Furthermore, the partition 103 separates a valve chamber containing the pre-stage valve 19 and the main stage valve 23 from an actuator chamber 117 within the valve housing 5 of the damping valve assembly 1.The partition 103 also includes a channel system 119 that connects the piston rod-side working chamber 25 of the working cylinder 9 with the second pressure chamber 105. To limit the closing force on the pre-stage valve 19, the second control chamber 105 is operatively connected to a pressure relief valve 121. The pressure relief valve 121 is connected to the channel system 119 within the partition 103. The partition 103 is a functional component of the pressure relief valve 121. A valve disc 123 of the pressure relief valve 121 bears against a valve seat surface 125 of the partition 103. When a flow of fluid approaches the damping valve assembly 1, starting from a compression of the working chamber 27 furthest from the piston rod, the damping medium passes through the passive damping valve 35 and pressurizes the main stage valve body 37 within the connection chamber 65, within a pressurized area defined by the main stage valve seat surface 39. A control flow reaches the first control chamber 45 via the axial channel 69 and the open check valve 69, and further via the second throttle channel 59 to the second control chamber 61 within the valve stem 49. The pressure within the second control chamber 61 acts in the downward stroke direction of the pre-stage valve body 17. A hydraulic closing force is exerted on the main stage valve body 37 via the pressures in the two control chambers 45 and 61.The control volume flow passes through 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. 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 assembly 1. When fluid flows towards the damping valve assembly 1 from the piston rod-side working chamber 25, the displaced damping medium abuts 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 within the stage opening 43 of the valve housing ring 31. This pressure force also causes a lifting force on the main stage valve body. Hydraulically, the first control chamber 45 is also pressurized via the first throttle channel 47, resulting in a pressure increase in the second control chamber 61, which, together with the pressure increase in the first control chamber 45, causes a closing force on the main stage valve body 37.The control volume flow, which flows through the pre-stage valve 19 into the return chamber 71, also reaches the connecting channel 101, passes through the at least one radial channel 99 into the annular groove 91, and can then flow through the connecting openings 93 in combination with the channel system 87 into the connecting chamber 65 and then further through the passive damping valve 33 into the working chamber 27 furthest 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 opposing flow from the piston rod-side working chamber 25, so that the use of the four check valves 67, 69, 81, and 83 ensures that the control volume flow is directed in the opening direction through the pre-stage valve 19. A second control flow is present, originating from the piston rod-side working chamber 25 and leading to the pre-stage valve 19. This flow is fed via the connecting opening 85 into the channel system 119 within the partition 103 and into the second control chamber 107 of the pre-stage valve 19. The pressure within the second control chamber 107 exerts a closing force on the pre-stage valve 19. This balances the pressure force within the control chamber 61 in the guide pin 47 of the main stage valve body 23 and the pressure force in the second control chamber 107. If the pressure level within the second control chamber 107 exceeds a defined limit, the valve disc 123 of the pressure relief valve 121 lifts, and the resulting open connection to the return chamber 71 of the pre-stage valve 19 allows flow, together with the first control flow, from the control chamber 61 via the channel system 87 towards the connection chamber 65. Reference sign 1 Adjustable damping valve assembly 3 Vibration damper 5 Damping valve housing 7 Piston rod 9 Working cylinder 11 Actuator 13 Solenoid coil 15 Armature 17 Pre-stage valve body 19 Pre-stage valve 21 Return spring 23 Main stage valve 25 Piston rod-side working chamber 27 Piston rod-remote working chamber 29 Radial connection channel 31 Valve housing ring 33 Passive damping valve 35 Passive damping valve 36 Piston 37 Main stage valve body 39 Main stage valve seat surface 41 Valve ring 43 Stage opening of the valve housing ring 45 First control chamber 47 First throttle channel 49 Valve pin 51 Pre-stage valve seat surface 53 Connection opening 55 Axial channel 57 Intermediate wall 59 Second throttle channel 61 Second control chamber 63 Axial channel 65 Connection chamber 67 Check valve 69 Check valve 71 Return chamber 73 Check valve assembly 75 Check valve ring 77 Check valve disc 79 Check valve disc 81 Check valve 83 Check valve 85 Connecting opening 87 Channel system 89 Through opening 91Ring trench 93 Connection opening 95 Support surface 97 Support surface 99 Radial channel 101 Connection channel 103 Partition wall 105 Second pressurized surface 107 Second control chamber 109 Guide pin of the pre-stage valve body 111 Through opening of the partition wall 113 Bottom of the second control chamber of the pre-stage valve 115 Valve chamber of the damping valve assembly 117 Actuator chamber 119 Channel system within the partition wall 121 Pressure relief valve for the second control chamber 123 Valve disc of the pressure relief valve 125 Valve seat surface of the pressure relief valve

Claims

Adjustable damping valve device (1) for a vibration damper (3), wherein the damping valve device (1) 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 (1), wherein the damping valve device (1) comprises a main stage valve (23) and a pre-stage valve (19) hydraulically controlling the main stage valve (23), wherein the pre-stage valve (19) has a control chamber (61) whose pressure level is influenced by a throttle cross-section of the pre-stage valve (19), wherein a pre-stage valve body (17) has a pressurized area in the stroke direction of the pre-stage valve body which, in the event of an inflow from both the piston rod-remote and the piston rod-side working chamber (25;27) in conjunction with the pressure in the control chamber (61) generates a lifting force, characterized in that the pre-stage valve (19) has an additional second pressurized surface (105) effective in the closing direction of the pre-stage valve for an inflow from one of the two working chambers (25; 27), wherein the second pressurized surface (105) interacts with a second control chamber (107) of the pre-stage valve (19). Adjustable damping valve device (1) according to claim 1, characterized in that the second control chamber (107) is operatively connected to a pressure relief valve (121). Adjustable damping valve device (1) according to one of claims 1 or 2, characterized in that the pre-stage valve body (17) has a guide pin (109) wherein the guide pin (109) carries the second pressurized surface (105). Adjustable damping valve device (1) according to claim 3, characterized in that the guide pin (109) of the pre-stage valve body (17) engages in a through-opening (111) of a partition (103) within the damping valve device (1) and the second control chamber (107) is at least partially formed by the partition (103). Adjustable damping valve assembly (1) according to claim 4, characterized in that the partition (103) separates a valve chamber (115) with the pre-stage valve (19) and the main stage valve (23) from an actuator chamber (117) of a valve housing (5) of the damping valve assembly (1). Adjustable damping valve device (1) according to claim 4 or 5, characterized in that the partition (103) comprises a channel system (119) that connects a working chamber (25; 27) of the working cylinder (9) with the second pressure chamber (107). Adjustable damping valve device (1) according to claim 6, characterized in that the pressure relief valve (121) is connected to the channel system (11). Adjustable damping valve device (1) according to claim 7, characterized in that the partition (103) is a functional component of the pressure relief valve (119). Adjustable damping valve device (1) according to claim 8, characterized in that a valve disc (123) of the pressure relief valve (121) is supported on a valve seat surface (125) of the partition wall (103).

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