Adjustable damping valve device for a vibration damper

Abstract

Adjustable damping valve device for a vibration damper, comprising a damping valve housing in which a pre-stage valve for hydraulically controlling a main stage valve is arranged, wherein the damping valve housing is hydraulically connected to a piston rod-side and a piston rod-remote working chamber of a working cylinder of the vibration damper, wherein the damping valve device has a check valve arrangement for rectifying a control volume flow from the working chambers of the working cylinder to the pre-stage valve, wherein a pre-stage valve body of the pre-stage valve has a first pressurized surface for an inflow from the piston rod-side working chamber and a second pressurized surface for an inflow from the working chamber remote from the piston rod.

Description

The invention relates to an adjustable damping valve device for a vibration damper according to the preamble of claim 1.DE 44 18 972 A1 relates to an adjustable damping valve device which comprises a valve housing on a piston rod of a vibration damper. The functional advantage of this damping valve device consists in the use of a single pre-stage valve for controlling a main stage valve in the event of an inflow proceeding from a working space on the piston rod side and from a working space remote from the piston rod.For this purpose, the damping valve device has a total of four check valves which ensure the rectification of a volume flow proceeding from the working chamber on the piston rod side and the working chamber remote from the piston rod to the pre-stage valve and for the outflow from the rear chamber of the pre-stage valve to the two working chambers. The check valves which switch the inflow are embodied on or in the main stage valve body.The rectification of the volume flow for the pre-stage valve is also associated with an adaptation of the operating behavior of the entire damping valve device, since the pre-stage valve also acts on a common main stage valve. Although pressure can be applied to surfaces of different sizes at the main stage valve for the two inflow directions from the working spaces, the damping force ratio of the pull / pressure direction that can be achieved thereby is not sufficient for some applications.DE 41 09 471 A1 discloses a damping valve device with a pre-stage valve, which is connected with its conical valve body to a first control chamber. This first control chamber is supplied with flow independently of the working direction of the vibration damper by the use of a plurality of check valves via an access throttle. In the outflow direction, the pre-stage valve body has a second circular ring-shaped pressurized surface which is likewise loaded in the same direction independently of the working movement. The second control chamber is connected to a rear side of the pilot valve body via a pressure compensation channel. This pressure compensation channel serves to hydraulically connect a back chamber of the pre-stage valve to the flow channels of the damping valve device so that the pre-stage valve is not hydraulically blocked.DE 10 2015 218 292 A1 likewise discloses an adjustable damping valve device having a plurality of nonreturn valves for rectifying a volume flow through a pre-stage valve. Here too, the flow to the pre-stage valve is identical, regardless of the working direction.The object of the present invention is to realize a damping valve device with a pre-stage valve which acts for both working directions of the vibration damper, wherein the damping force ratio is to be increased when the damping valve device is subjected to alternating flow.The object is achieved by the features of claim 1.By utilizing two pressurized surfaces for different inflow directions of the damping valve device, a large effect with respect to the damping force characteristic can be achieved in a comparatively small installation space. The achievable difference between the damping force level during an extension movement of the piston rod in comparison with the achievable damping force level during an extension movement of the piston rod into the working cylinder is significantly greater than if only the pressurized surfaces on the main stage valve were used for this measure. The control chamber can also be a working chamber of the vibration damper. An important advantage of this design is the simplified assembly of the pre-stage valve and its higher functional reliability. If, for example, the second surface subjected to pressure is oriented counter to the direction of stroke of the plate-shaped valve body as a second functional section, then a distancing movement can be established between the two functional sections in the event of a pressure load on the second surface subjected to pressure, whereby the said radial expansion of the first surface subjected to pressure changes.When an inflow starts from one of the two working spaces, the first and the second pressure-impinged surface are loaded, and when an inflow starts from the other of the two working spaces, only the first pressure-impinged surface is loaded. By means of this measure, the desired damping force difference can be increased once more.Thus, a functional section is formed by a control tappet which has a control surface acted upon by the pressure in the first control chamber. The control tappet can cooperate with a plate-shaped valve body known per se as a second functional section of the pre-stage valve.In a further advantageous embodiment, the control tappet for the pre-stage valve has a second surface which is subjected to pressure and is subjected to the pressure in the second control chamber of the pre-stage valve. The second pressure-applied surface can be used, for example, for the pressure in the control chamber to connect the two functional sections of the pre-stage valve to one another.A particularly space-saving design of the pre-stage valve is distinguished in that a functional section is guided axially movably within the main stage valve body.With regard to the design implementation, it is appropriate if the functional section that is axially movable within the main stage valve body penetrates the main stage valve body axially in the pressure direction to one of the working spaces and has a surface to which the pressure prevailing in this working space is applied.For defined positioning of the axially movable control tappet, a biasing spring connects the two functional sections of the pre-stage valve body to one another.It can also be provided that the pre-stage valve has three control chambers, wherein at least two control chambers are pressurized in the direction of withdrawal of the pre-stage valve in the inflow direction of the pre-stage valve from the working chambers. The third control chamber is used for both inflow directions of the damping valve device to provide a hydraulic force which moves the control plunger in the direction of the plate-shaped valve body and connects it to the latter.With regard to simple flow paths within the damping valve device, it can also be provided that a control chamber for the main stage valve body is connected to two control chambers of the pre-stage valve.In order to avoid a hydraulic short circuit via the pre-stage valve, a control chamber of the main stage valve and the second control chamber of the pre-stage valve are separated by a check valve, which blocks a flow from the control chamber of the main stage valve to the second control chamber of the pre-stage valve.The invention will be explained in more detail with reference to the following description of the figures.It shows: FIG. 1 is a section through the damping valve device FIGS. 2-4 show a detailed representation of the main stage valve body of FIG. 1 in various embodiments FIG. 5 shows an alternative embodiment to FIG. 1 FIG. 6 shows a detailed illustration of FIG. 4 FIG. 7 shows a detailed illustration of the nonreturn valve arrangement on the outflow side from the preliminary stage valve according to FIGS. 1 and. 5FIG. 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. The damping valve housing 5 and thus also the damping valve device 1 can however also be arranged spatially outside the vibration damper 1 and be hydraulically connected, for example, via a pipe or hose connection.The damping valve device 1 comprises an electromagnetic actuator 11 with a magnetic coil 13 and an armature 15, which acts on the end side on a pre-stage valve body 17 of a pre-stage valve 19. The force of the magnet coil 13 acts against at least one restoring spring 21.The pre-stage valve 19 serves for the hydraulic control of a main stage valve 23, via which a working chamber 25 on the piston rod side and a working chamber 27 remote from the piston rod are connected to one another within the working cylinder 9. FIG. 1 shows radial connecting 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 to the main stage valve 23. Between the working chamber 27 remote from the piston rod and the main stage valve 23, a passive damping valve 33; 35 is arranged for a respective flow direction of the damping valve device 1. The two passive damping valves 33; 35 are optionally used. 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 that 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 spaces 25; 27.The main stage valve 23 includes a main stage valve body 37 and a main stage valve seat surface 39 (see FIG. 2 ) formed by a valve ring 41 inside 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. In this case, the main stage valve body 37 is sealed off from an inner lateral surface 43A of the stage opening 43. The main stage valve body 37, a part of the jacket surface 43A and a bottom 43B of the stage opening 43 form a control chamber 45 for the main stage valve 23, which control chamber 45 is connected via at least one first throttle channel 47 to the radial connecting channels 29, wherein, due to the throttle function of the throttle channel 47, there is a pressure drop 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 has an effect as closing force for the main stage valve 23.The main stage valve body 37 has a valve pin 49 which points in the direction of the pre-stage valve 19 and has a pre-stage valve seat surface 51 on the end side for the plate-shaped pre-stage valve body 17. The valve pin 49 is hollow and has at least one radial connecting opening 53 to an axial channel in which the same pressure is present as in the first control chamber 45.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 23, and for the pre-stage valve 19 the axial channel forms a first control chamber 57 with a pressure force component in the direction of the downward stroke of the pre-stage valve 19.At least one connecting channel 63 having a throttle function similar to the first throttle channel 47 runs within the main stage valve body 37, said connecting channel connecting a connecting chamber 65 of the damping valve device 1 to the first control chamber 45. Thus, the connection chamber 65 is also connected to the first control chamber 57 of the pre-stage valve 19. To avoid a hydraulic short circuit via the first control chamber 45, the throttle channel 47 and the connection channel 63 are each equipped with a check valve disk 67; 69, which opens in the direction of the control chamber 45 of the main stage valve body 37.In the present embodiment of the damping valve device 1, the pre-stage valve body 17 has a first pressurized surface D 1 for an inflow proceeding via the connection channels 29 and the throttle channel 47. The first pressurized surface D 1 is defined at the edge side by the precursor valve seat surface 51. The pre-stage valve body 17 comprises two functional sections which are movable and separable relative to one another, namely the plate-shaped pre-stage valve body 17 vwhich rests on the pre-stage valve seat surface 51 and a control plunger 17 swhich completely penetrates the first control chamber 57 of the pre-stage valve 19 in the pressure direction to the working chamber 27 remote from the piston rod, is guided within the main stage valve body 37 and projects as far as into a second control chamber 58 of the pre-stage valve 19. The second control chamber 58 is in this case identical to the connection chamber 65, which is in turn part of the working chamber 27 remote from the piston rod. The effective cross section of the control plunger 17s defines an inner edge of the first pressurized surface D 1. The two control chambers 57; 58 of the pre-stage valve 19 are hydraulically separated by a partition wall 60 of the valve housing ring 31, wherein the control plunger 17 sis guided within the partition wall 60 in an axially movable manner.An end face of the control plunger 17 sin the second control chamber 58 of the pre-stage valve 19 forms a second pressure-loaded surface D 2, for the pre-stage valve 19, which is effective only in the event of an inflow proceeding from the working chamber 27 remote from the piston rod.A biasing spring 99 connects the two functional sections 17 s; 17 vof the pre-stage valve body 17 in that the biasing spring 99 is supported on a valve disk 37 vof the main stage valve 23 and acts on a circumferential collar of the control plunger 17 s.When the damping valve device 1 is supplied with flow from the working chamber 27 remote from the piston rod, the damping medium passes the passive damping valve 35 and reaches the main stage valve 23 via the connecting chamber 65, As already described, the connecting chamber 65 represents the second control chamber 58, the pressure of which is effective on the surface D 2 of the pre-stage valve body 17 or of the control plunger 17 s, which surface is subjected to the second pressure, in the direction of excavation.A control volume flow flows via the connection channel 63 and the lifted non-return valve disk 69 into the first control chamber 45 and further into the second control chamber 55 of the main stage valve 23 or the first control chamber 57 of the pre-stage valve 19, respectively. the non-return valve disk 67 closes the throttle channel 47 in the direction of the connection openings 29. The pressure within the first control chamber 57 of the pre-stage valve 19 generates, in conjunction with the surface D 1 subjected to the annular pressure, a further hydraulic lifting force on the pre-stage valve body 17, in particular on the plate-shaped pre-stage valve body 17 v.When the damping valve device 1 is supplied with flow from the working chamber on the piston rod side, the damping medium enters the valve housing 5 via the connection openings 29 to the main stage valve 23 and reaches the first control chamber 45 of the main stage valve 23 via the throttle channel 47 and the lifted check valve disk 67. For an inflow from the working chamber 27 remote from the piston rod, the pre-stage valve 19 has the second surface D 2 subjected to pressure, wherein the pre-stage valve 19 has the first control chamber 57 for the first surface D 1 subjected to pressure and the second control chamber 58 for the second surface D 2 subjected to pressure, which are hydraulically separated, but the first and the second surfaces D 1; D 2 subjected to pressure are subjected to pressure in the case of an inflow starting from the working chamber 27 remote from the piston rod. The significant difference in surface area in the pressurized surfaces, namely the surface D 1 leads to a significantly greater lifting force on the pre-stage valve 19 upon an inflow proceeding from the working chamber 27 on the piston rod side. This greater lifting force tends to open the pre-stage valve 19 more strongly at a low damping medium pressure within the working chamber 27 remote from the piston rod than at an identical pressure in the working chamber 25 on the piston rod side. The pressure in the first and in the second control chamber of the main stage valve is thus lowered, whereby the hydraulic closing force on the main stage valve body 37 is in turn reduced. As a result, the main stage valve 23 opens at a comparatively lower damping medium pressure in the working chamber 27 remote from the piston rod in comparison with an inflow from the working chamber 25 on the piston rod side.FIG. 3 shows an embodiment of the invention in which the control tappet 17 sdoes not protrude beyond the main stage valve body 37 as far as into the connection chamber 65, but rather the second control chamber 58 is designed as an axial channel which extends from the connection chamber 65 as far as the end face D 2 of the control tappet 17 s. In this example, the control chamber 58 is designed as a stepped bore, wherein the step can represent a support surface for the control tappet 17 s. In contrast to the embodiment according to FIG. 2, the control tappet 17 shas an annular control surface 66 which points in the direction of the plate-shaped pre-stage valve body 17 v. This control surface 66 in conjunction with the pressure in the first control control chamber 57 ensures a holding force on the control plunger 17 sfor permanent connection to the plate-shaped pre-stage valve body 17 v. When there is an incident flow from the working chamber 25 on the piston rod side, the holding force acts from the control surface 66, and if the working chamber remote from the piston rod is compressed, then the pressure on the surface D 2 subjected to the second pressure ensures the holding force. The holding forces can be of quite different magnitude.FIG. 4 discloses yet another possibility for configuring the control chambers 57; 58 and the control tappet 17 swith the aim of obtaining a hydraulic coupling between the two functional sections 17 s; 17 vof the pre-stage valve body 17. In this variant, the pre-stage valve 19 has three control chambers 57; 58; 105, wherein, when the pre-stage valve 19 is supplied with pressure from both working chambers 25; 27, at least two control chambers are pressurized in the direction of the stroke of the pre-stage valve 19. As in the embodiment according to FIG. 3, a stepped bore is present in the main stage valve body 37, but this bore has two shoulders, wherein one shoulder in each case forms a boundary between two adjacent control chambers. The control tappet 17 shas a simple stepped profile with a first longitudinal section 17 s 1, the diameter of which is smaller than the diameter of the first control chamber 57.The first longitudinal section 17 s 1 of the control plunger 17 sextends as far as a third control chamber 105, which adjoins the first control chamber 57 in the direction of the second control chamber 58.The third control chamber 105 has a diameter which is matched to the diameter of a first longitudinal section 17 s 1 of the control plunger 17 s, wherein the first longitudinal section 17 s 1 in each stroke position of the control plunger 17 sis in overlapping relationship with the third control chamber 105, such that the wall of the third control chamber 105 forms a guide for the control plunger 17 s. The second longitudinal section 17 s 2 of the control plunger 17 sis of the same diameter as the third control chamber 105 and extends within the second and third working chambers 58; 105.The third control chamber 105 has a separate connection opening 54 to the control chamber 45 of the main stage valve 23, and the diameter of this connection opening 54 can be selected to be significantly smaller than the diameter of the connection opening 53 between the first control chamber 57 of the pilot stage valve 19 and the control chamber 45 of the main stage valve 23, for example.When the pilot-stage valve 19 flows from the working chamber 25 on the piston rod side via the throttle channel 47 into the control chamber 45, both the first and the third control chamber 57; 105 are supplied with a control volume flow and exert a lifting force on the plate-shaped pilot-stage valve body 17 v. In this case, the annular pressure-impinged surface D 1 is effective in the first control chamber, and a likewise annular pressure-impinged surface D 3 is effective in the third control chamber. The area D 3 is determined from the diameter of the third control chamber 105, which is smaller than the diameter D1 of the first control chamber. The control tappet 17 sin the third control chamber 105 has the same diameter D 2 as in the second control chamber 58, which spatially adjoins the third control chamber 105. The size of the third pressurized surface D 3 is therefore determined by the diameter of the third control chamber 105 and the diameter of the first longitudinal section 17 s 1 of the control plunger 17 s.When there is an inflow via the connecting chamber 65 or the working chamber 27 remote from the piston rod, the surface D 2 on the control tappet is acted upon directly. A portion of the control volume flows via the connecting channel 63 into the control chamber 45 and further into the first and third control chambers 57; 105, so that a total of three control chambers 57; 58; 105 are then active, the lifting force of which is in total greater than the lifting force when the pilot valve 19 is supplied with flow from the piston rod-side working chamber 25, wherein only the pressure force from the first and third control chambers 57; 105 of the pilot valve 19 is then active.The embodiment according to FIG. 5 shows a variant of the invention in which the two functional sections 17 s; 17 vof the pre-stage valve body 17 are mounted so as to be movable relative to one another at least in the longitudinal direction. Between the two functional sections 17 s; 17 v, an elastomeric coupling element 62 is present, which is axially prestressed against the plate-shaped pre-stage valve body 17 vby a tension spring 64, for example within the second control chamber 58. The axial compression of the coupling element 62 determines the cross section of a contact surface on the plate-shaped pre-stage valve body 17 v. The effective pressure-loaded surface D 1 within the first control chamber 57 is determined, as already described in connection with the preceding figures, from the inner diameter of the pre-stage valve seat surface 51 minus the contact surface of the coupling element 62 on the plate-shaped pre-stage valve body 17 v. Consequently, the radial extent of the first pressurized surface D 1 is determined by the relative axial position of the two functional portions 17 s; 17 vof the pilot valve body 17.Within the first control chamber 57 of the pre-stage valve 19, the control tappet 17 shas a stepped profile with the annular control surface 66, which is loaded by the pressure within the first control chamber 57 of the pre-stage valve 19 and moves the control tappet 17 sin the direction of the second control chamber 58 of the pre-stage valve 19 counter to the force of the tension spring 64.By means of the stroke of the pre-stage valve body 17 from the pre-stage valve seat surface 51, a throttle cross section is defined which in turn determines the pressure level both in the first and in the second control chamber 45; 55 of the main stage valve. The pressures in the two control chambers 45; 55 multiplied by the axially pressurized surfaces on the main stage valve body result in a closing force acting on the main stage valve body 37, which determines the damping force of the vibration damper 3 with a predetermined working movement of the vibration damper 3.Regardless of the configuration of the pre-stage valve with its control chambers and the control tappet, the damping medium displaced by the pre-stage valve 19 reaches, in all variants of the damping valve device, a return chamber 71 of the pre-stage valve 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 equipped on both sides with at least one check valve disk 77; 79. The check valve ring 75 represents a component which is separate and replaceable from the valve housing ring 31. The check valve disks 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 flow direction starting from the check valve arrangement 73 in the direction of the working chamber 25 on the piston rod side, the damping valve housing 5 has at least one, in this example, radial connecting opening 85. for the connection of 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 which opens into the connecting chamber 65. When the check valve arrangement 73 is supplied with flow starting from one of the two working spaces 25; 27, the check valve 81; 83 supplied with flow directly, i.e. bypassing the pre-stage valve 19, is closed.The check valve ring 75 is centered on the valve housing ring 31 via its central through-opening 89 and has an annular trench 91 in the direction of the rear chamber 71, which trench in turn comprises axial connection openings 93 to the channel system 87 in the valve housing ring 31. The annular groove 91 is radially delimited by two annular supporting surfaces 95; 97 for the nonreturn valve disc 77. An inner support surface 97 is interrupted by at least one radial channel 99, which connects the annular trench 91 to a radially inner connection channel 101. The connection channel 101 communicates the back chamber 71 of the pre-stage valve 19 with the connection openings 93 (FIG. 7 )The downward stroke movement of the check valve disk 79 for the channel system 87 in the valve housing ring 31 is limited by the valve housing ring 31. A cover ring 103 serves for the downward stroke movement of the check valve disk 77 on the upper side of the check valve ring 75, which additionally axially fixes the check valve ring 75 within the damping valve housing 5.When the damping valve device 1 according to FIGS. 5 to 7 is supplied with an inflow proceeding from a compression of the working chamber 27 remote from the piston rod, the damping medium passes the passive damping valve 35 and ensures, within the connection chamber 65, a pressurization of the main stage valve body 37 within a pressurization surface bounded by the main stage valve seat surface 39. A control volume flow reaches second control chamber 58 of the pre-stage valve 19 via the connection channel 63; at least one radial channel 72 connects the second control chamber 58 of the pre-stage valve 19 to the first control chamber 45 of the main stage valve 23 The check valve 70, formed for example via a slightly prestressed O-ring on the valve pin 49 of the main stage valve body 37, is open in this case. The control volume flow continues the flow path via the at least one connection opening 53 into the first annular control chamber 57 of the pilot valve 19. Thus, the first pressurized surface D 1 on the pilot valve body 17 and the second pressurized surface D 2 on the control plunger 17s are loaded in the direction of the downward stroke of the pilot valve 19.By means of the pressures in the two control chambers 45; 55, a hydraulic closing force is also exerted on the main stage valve body 37. The control volume flow flows via the pre-stage valve 19 and the non-return valve disk 77, which is lifted from the non-return valve ring 75, through the connecting opening 85 into the working chamber 27 on the piston rod side.The damping medium acting on the nonreturn valve 83 via the duct system 87 in the valve housing ring 31 closes this nonreturn valve 83, and the nonreturn valve 68 of the main stage valve body 37 is also closed in this inflow situation of the damping valve device 1.When the damping valve device 1 is supplied with flow from the working chamber 25 on the piston rod side, 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 which extends inside the lateral surface 43A of the valve housing ring 31. This pressure force also causes a lifting force on the main stage valve body 37. Hydraulically in parallel, the first control chamber 45 of the main stage valve 23 is also pressurized 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 pressure increase, together with the pressure increase in the first control chamber 45, causes a closing force on the main stage valve body 37.The pressure in the control chamber 45 closes the check valve 70 to the second control chamber 58 of the pre-stage valve 19, The control volume flow in the first control chamber 57 of the pre-stage valve also exerts a lifting force here on the plate-shaped pre-stage valve body 17 v, but only on the ring-shaped surface D 1. subjected to the first pressure. As a result, the first control chamber 57 of the pre-stage valve 19 is also hydraulically separated from the second control chamber 58 of the pre-stage valve 19. The control tappet 17 sis loaded against the force of the tension spring 64 via the control surface 66 acted upon by the pressure in the first control chamber 57 of the pilot valve 19. Starting from a defined pressure level within the first control chamber 57 of the pre-stage valve 19, the control plunger 17 smoves in the direction of the second control chamber 58 of the pre-stage valve 19, as a result of which the compression of the elastomeric coupling element 62 to the plate-shaped pre-stage valve body 17 vsides and the cross section of the pressurized surface D 1 increases as a result. This surface area and thus a force increase on the pre-stage valve body 17 vcan be used to tend to open the pre-stage valve 19 more strongly. If it is desired to do without the pressure-dependent change in the size of the first pressure-loaded surface D 1 then the control tappet 17 scan be used fixedly with the plate-shaped preliminary stage valve body 17 vand a control tappet without a control surface 66.The control volume flow flowed out into the rear chamber 71 through the pre-stage valve 19 then likewise reaches the connection channel 101, reaches the annular trench 91 via the at least one radial channel 99 and can then flow out into the connection chamber 65 via the connection openings 93 in combination with the channel system 87 and then further through the passive damping valve 33 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 inflow from the piston rod-side working chamber 25, so that by using the total of four check valves 68; 70; 81; 83 used, rectification of the control volume flow by the pre-stage valve 19 is achieved.Reference numerals denote reference numerals1 Adjustable damping valve device 3 Vibration damper 5 Damping valve housing 7 Piston rod 9 Working cylinder 11 Actuator 13 Solenoid 15 Armature 17 Pilot stage valve body 17 sControl plunger of the pilot stage valve body 17 vPlate-shaped pilot stage valve body 19 Pilot stage valve 21 Restoring spring 23 Main stage valve 25 Piston rod-side working chamber 27 Working chamber 29 Radial connecting passage 31 Valve housing ring 33 Passive damping valve 35 Passive damping valve 36 Piston 37 Main stage valve body 37V Valve disk of the main stage valve body 37A Closing body of the main stage valve body 37B Separating piston of the main stage valve body 39 Main stage valve seat surface 41 Valve ring 43 Stage opening of the valve housing ring 43A Lateral surface of the stage opening 43B Bottom of the stage opening 45 First control chamber 47 First throttle passage 49 Valve pin 51 Pilot stage valve seat surface 53 Connection opening 55 Second control chamber of the main stage valve 57 First control chamber of the pre-stage valve 58 Second control chamber of the pre-stage valve 60 Partition wall 61 Second control chamber 62 Coupling element 63 Connection channel 64 Tension spring 65 Connection chamber 66 Control surface on the control plunger 67 Check valve disk 68 Check valve 69 Check valve disk 70 Check valve 71 Return chamber 72 Radial channel 73 Check valve arrangement 75 Check valve ring 77 Check valve disk 79 Check valve disk 81 Check valve 83 Check valve 85 Connection opening 87 Channel system 89 Through opening 91 Annular groove 93 Connection opening 95 Support surface 97 Support surface 99 Bias spring 101 Connection channel 103 Cover ring 105 Third control chamber D 1 First pressurized surface D 2 Second pressurized surface d 3 third pressurized surface

Claims

Adjustable damping valve device (1) for a vibration damper (3), comprising a damping valve housing (5) in which a preliminary stage valve (19) for the hydraulic control of a main stage valve (23) is arranged, wherein the damping valve housing (5) is hydraulically connected to a working chamber (25; 27), on the piston rod side and remote from the piston rod, of a working cylinder (9) of the vibration damper (3), wherein the damping valve device (1) is connected via a check valve arrangement (73) for rectifying a control volume flow proceeding from the working chambers (25; 27) of the working cylinder (9) to the pre-stage valve (19), characterized in that a pre-stage valve body (17) of the pre-stage valve (19) has a first pressurized surface D 1 for an inflow from the working chamber (25) on the piston rod side and a second pressurized surface D 2 for an inflow from the working chamber (27) remote from the piston rod side, wherein the pre-stage valve (19) has a first control chamber (57) for the first pressurized surface D 1 and a second control chamber (58) for the second pressurized surface D 2 which are hydraulically separated, wherein the pre-stage valve body (17) has two functional sections (17v; which are movable relative to one another; 17 s), which together radially delimit the first pressurized surface D 1 on the pre-stage valve body (17), wherein the radial extent of the first pressurized surface D 1 is determined via the relative axial position of the two functional sections (17 s; 17 v) to one another.Adjustable damping valve device (1) according to Claim 1, characterized in that, in the case of an inflow proceeding from one of the two working spaces (25; 27), the first and the second pressure-loaded surface D 1; D 2 is loaded, and, in the case of an inflow proceeding from the other of the two working spaces (25), only the first pressure-loaded surface D 1 is loaded.Adjustable damping valve device (1) according to Claim 1, characterized in that a functional section is formed by a control tappet (17s), which has a control surface (66) which is acted upon by the pressure in the first control chamber (57).Adjustable damping valve device (1) according to at least one of Claims 1 to 3, characterized in that the control tappet (17s) for the pre-stage valve (19) has a second pressure-loaded surface D 2 which is loaded by the pressure in the second control chamber (58) of the pre-stage valve (19).Adjustable damping valve device (1) according to at least one of Claims 1 - 4, characterized in that the functional section (17s) is guided axially movably within the main stage valve body (37).Adjustable damping valve device (1) according to Claim 5, characterized in that the functional section (17s) which is axially movable within the main stage valve body (37) penetrates the main stage valve body (37) axially in the pressure direction to one of the working spaces (27) and has a pressurized surface D 2 which is dependent on the pressure prevailing in this working space (27).Adjustable damping valve device (1) according to at least one of Claims 1 - 6, characterized in that a prestressing spring (99) connects the two functional sections (17s; 17v) of the pre-stage valve body (17) to one another.Adjustable damping valve device (1) according to at least one of Claims 1 to 7, characterized in that the pre-stage valve (19) has three control chambers (57; 58; 105), wherein at least two control chambers are pressurized in the direction of stroke of the pre-stage valve (19) out of the working chambers (25; 27).Adjustable damping valve device (1) according to Claim 8, characterized in that a control chamber (45) for the main stage valve body (37) is connected to two control chambers (57; 58) of the pre-stage valve (19).Variable damping valve device (1) according to at least one of Claims 1 to 3, characterized in that the first control space (45) of the main stage valve (23) and the second control space (58) of the pre-stage valve (19) are separated by a nonreturn valve (70) which blocks a flow from the first control space (45) of the main stage valve (23) to the second control space (58) of the pre-stage valve (19).

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