Damping valve device for a shock absorber of a motor vehicle

Abstract

The invention comprises a vibration damper (10) of a motor vehicle, comprising an outer tube (12) and an inner tube (14) arranged coaxially thereto, and a working piston (18) arranged axially movable within the inner tube (14), which divides the interior of the inner tube (14) into a working chamber (22) on the piston rod side and a working chamber (24) remote from the piston rod, a damping valve device (54) arranged in the working piston (18), wherein the damping valve device (54) comprises: a coil (52), an axially movable armature (62) arranged at least partially within the coil (52), a main valve (68) with a main piston (76) which separates a pressure main control chamber (82a), a rebound main control chamber (82b) and a pilot control chamber (84) from one another, a pilot valve (70) which is designed such that it can be actuated in the rebound stage and in the compression stage by Hydraulic fluid can flow through,with a pilot working chamber (100) and a sliding tappet (102) arranged in the pilot working chamber (100), which is axially movable by means of the armature (62), and a connecting channel (98) arranged between the pilot control chamber (84) and the pilot working chamber (100) and fluidically connecting them, wherein the pressure main control chamber (82a) is fluidically connected to the pilot control chamber (84) via a first flow passage (86a) and the tension main control chamber (82b) is fluidically connected to the pilot control chamber (84) via a second flow passage (86b).

Description

[0001] The invention relates to a damping valve device for a shock absorber for motor vehicles, wherein the damping valve device has a main valve and a pilot valve.

[0002] DE 10 2020 215 480 A1 discloses a vibration damper with a damping valve device. The damping valve device has a pilot valve adjustable via a solenoid coil. Particularly during dynamic operation of the vibration damper, unstable behavior of the damping valve can occur when the main valve opens and closes. In addition, acoustic problems arise during the switching process of the main valve. Furthermore, the damping valve devices are relatively large and therefore take up a lot of space.

[0003] The object of the present invention is therefore to provide a damping valve device for a vibration damper which is particularly space-saving and at the same time has a stable damping behavior in both the compression stage and the rebound stage and can be produced cost-effectively.

[0004] This object is achieved according to the invention by a vibration damper with a damping valve device having the features of independent device claim 1. Advantageous further developments emerge from the dependent claims.

[0005] According to a first aspect, a vibration damper of a motor vehicle comprises an outer tube and an inner tube arranged coaxially therewith, and a working piston arranged axially movable within the inner tube, which divides the interior of the inner tube into a working chamber on the piston rod side and a working chamber remote from the piston rod. The vibration damper also comprises a damping valve device arranged in the working piston, wherein the damping valve device has a coil and an axially movable armature arranged at least partially within the coil. The damping valve device also comprises a main valve with a main piston, which fluidically separates a pressure main control chamber, a tension main control chamber, and a pilot control chamber from one another.The damping valve device also has a pilot valve, which is designed and arranged such that hydraulic fluid can flow through it in the rebound and compression stages. It has a pilot working chamber and a sliding plunger arranged in the pilot working chamber, which is axially movable by means of the armature. Furthermore, the damping valve device has a connecting channel arranged between the pilot control chamber and the pilot working chamber, fluidically connecting them. The main compression control chamber is fluidically connected to the pilot control chamber via a first flow passage, and the main rebound control chamber is fluidically connected to the pilot control chamber via a second flow passage.

[0006] The provision of a first and a second flow passage connecting the main control chambers to the pilot control chamber ensures flow through the pilot valve during the compression and rebound stages of the vibration damper. The compression main control chamber and the rebound main control chamber are each fluidically connected to the pilot control chamber.

[0007] The damping valve device is, for example, a pressure relief valve, which can preferably be pilot-operated. The main valve with the main piston is preferably designed to close and open the damping valve device, in particular the pressure relief valve. The main piston is preferably axially movable by means of the armature and / or the hydraulic pressure present in the pilot chamber.

[0008] A damping valve device designed as a pilot-operated pressure relief valve preferably comprises, in addition to the main valve, a pilot valve with a pilot working chamber and a sliding plunger arranged in the pilot working chamber, which is axially movable by means of the armature, and a connecting channel which is arranged between the pilot control chamber and the pilot working chamber and fluidically connects them to one another.

[0009] The damping valve device is arranged, for example, in a vibration damper for a motor vehicle. The vibration damper is, for example, a single-tube vibration damper or a multi-tube vibration damper, for example a twin-tube vibration damper. The vibration damper comprises, for example, an outer tube that forms an outer surface, in particular a housing, of the vibration damper. Arranged within the outer tube, coaxial with the outer tube, is an inner tube, also referred to as a damper tube. A compensation chamber is formed between the outer tube and the inner tube, which is preferably at least partially filled with a hydraulic fluid. For example, the compensation chamber is partially filled with a gas.

[0010] A working piston connected to a piston rod is preferably arranged within the inner tube in such a way that it is movable within the inner tube, wherein the inner tube is preferably designed as a guide for the working piston. A damping valve device, for example, is arranged on the working piston. The working piston divides the interior of the inner tube, in particular, into a first working chamber on the piston rod side and a second working chamber remote from the piston rod.

[0011] The vibration damper preferably has a sealing assembly that fluidically seals the interior of the outer tube on the piston rod side. Opposite the sealing assembly, at the end remote from the piston rod, the interior of the outer tube is preferably fluidically sealed by a base piece. In particular, a base valve is arranged on the base piece, which is attached to the end of the inner tube remote from the piston rod.

[0012] The damping valve device comprises a preferably cylindrical damping valve housing, which has a substantially tubular tube part and a housing upper part attached to the tube part or formed integrally therewith. The tube part has, for example, a connection area that has one or more connection contacts for an electrical power supply to the damping valve device. The connection contacts for an electrical power supply are preferably connected to a drive unit.

[0013] The damping valve device preferably has a drive designed as an electromagnet, in particular a coil with a plurality of windings made of a current-conducting wire. The coil is preferably arranged within a housing of the damping valve device and comprises, for example, a coil carrier onto which the windings of the coil are wound. The coil preferably at least partially or completely encloses an armature chamber that extends centrally in the axial direction. An armature is preferably mounted for axial movement within the armature chamber. The armature is preferably mounted within the armature chamber so as to be slidable in the axial direction and comprises, for example, a central armature rod, which is, for example, tubular in shape and extends centrally in the axial direction through the armature chamber.The armature space is preferably delimited by an at least partially hollow cylindrical pole tube, which preferably serves as a guide for the armature.

[0014] The damping valve device preferably comprises a main valve and a pilot valve. The pilot valve is preferably arranged downstream of the main valve in the flow direction in both the compression stage and the rebound stage of the vibration damper. In particular, hydraulic fluid can flow through the damping valve device in both directions. The damping valve device arranged in the working piston preferably has exactly one main valve and / or exactly one pilot valve. A seal, in particular a sealing ring, is attached to the working piston, for example, and seals the working piston in a fluid-tight manner to the damper tube. The working piston preferably comprises a first fluid passage to the working chamber on the piston rod side. The damping valve device is preferably fluidly connected to the working chamber on the piston rod side via the first fluid passage.The first fluid passage is designed, for example, as a fluid inlet for admitting hydraulic fluid into the damping valve device when the piston rod moves in the pulling direction, and as a fluid outlet for discharging hydraulic fluid from the damping valve device when the piston rod moves in the pushing direction. The working piston preferably has a second fluid passage to the working chamber remote from the piston rod, via which the damping valve device is preferably fluidically connected to the second working chamber remote from the piston rod. The second fluid passage is preferably designed as a fluid inlet for admitting hydraulic fluid into an optional comfort valve and / or the main valve when the piston rod moves in the pushing direction, and as a fluid outlet for discharging hydraulic fluid from the optional comfort valve and / or the main valve when the piston rod moves in the pulling direction.

[0015] The main valve preferably comprises a main piston arranged for axial movement within a main working chamber. The main valve optionally comprises a housing part that at least partially delimits the main working chamber and forms an axial guide for the main piston. The main piston is preferably arranged such that it fluidically separates a pressure main control chamber, a tension main control chamber, and a pilot control chamber from one another. The main control chamber is understood to be the hydraulic chamber, which preferably directly adjoins the main piston and preferably applies a hydraulic force to it in the opening direction of the main valve.A main valve through which fluid can flow in the rebound and compression stages preferably has a pressure main control chamber designed and arranged such that it applies a hydraulic force in the opening direction to the main piston in the compression stage, and a rebound main control chamber designed and arranged such that it applies a hydraulic force in the opening direction to the main piston in the rebound stage. The main valve preferably has a main valve seat, wherein, in an open position of the main valve, a main flow channel is formed between the main piston and the main valve seat. The rebound main control chamber and the pressure main control chamber are preferably fluidly connected to one another via the main flow channel.The hydraulic pressure of the working chamber remote from the piston rod is preferably present in the pressure main control chamber, while the hydraulic pressure of the working chamber on the piston rod side is preferably present in the tension main control chamber.

[0016] The main valve seat is preferably formed on a guide element mounted in a fixed position within the damping device, wherein the main piston is movable relative to the guide element. In particular, a spring assembly is mounted on the main piston, which spring assembly rests against the main valve seat of the guide element when the main valve is in the closed position. The spring assembly preferably comprises a plurality of, in particular two, spring disks arranged coaxially to one another and preferably abutting one another. The spring disk of the spring assembly pointing toward the main pressure control chamber preferably rests against the main valve seat and, in particular, has a bypass opening.

[0017] The pilot control chamber is understood to be the hydraulic chamber, which preferably adjoins the main piston and preferably applies a hydraulic force to it in the closing direction of the main valve. The pilot control chamber is preferably arranged on the main piston opposite the main tension control chamber and the main pressure control chamber. For example, the main piston is designed such that the end face of the main piston facing the main pressure control chamber or the main tension control chamber, which is subjected to the hydraulic pressure of the main pressure control chamber or the main tension control chamber, is larger than the end face of the main piston facing the pilot control chamber, which is subjected to the hydraulic pressure of the pilot control chamber.

[0018] During operation of the damping valve device and upon movement of the piston rod in the compression direction, the hydraulic fluid preferably flows from the working chamber remote from the piston rod through the second fluid passage into the optional comfort valve, into the pressure main control chamber, wherein the pressure in the pressure main control chamber applies an opening force to the main piston and moves it axially upwards. The main piston lifts off the main valve seat and the hydraulic fluid flows through the main flow channel to the rebound main control chamber, in particular the second fluid passage, and then into the piston rod-side working chamber. At the same time, in particular hydraulically parallel thereto, a partial flow of the hydraulic fluid flows through the pressure flow passage in the main piston to the pilot control chamber and applies a closing force to the main piston in the direction of the main valve seat.The closing force determines the opening width of the main valve, in particular the cross-section of the main flow channel, which determines the damping force of the damping valve device. The pressure in the pilot control chamber is preferably adjusted by the pilot valve, wherein the hydraulic fluid flows from the pilot control chamber through the connecting channel into the pilot working chamber, which is opened by the sliding tappet. The opening width, in particular the outflow cross-section, of the connecting channel is preferably dependent on the axial position of the sliding tappet, which is adjusted by means of the solenoid coil. In the closed position of the pilot valve, the sliding tappet preferably completely closes the connecting channel, so that the hydraulic pressure in the pilot control chamber rises to a maximum value and the main valve is closed by pressing the main piston onto the main valve seat.In an open position of the pilot valve, the connecting channel is at least partially released by the sliding tappet.

[0019] According to a first embodiment, a flow throttle is arranged in each of the first flow passage and the second flow passage. The first flow passage preferably extends at least partially or completely through the main piston and preferably fluidically connects the pressure main control chamber to the pilot control chamber. In particular, the first flow passage extends centrally and in the axial direction through the main piston. The second flow passage is arranged, for example, in a fixed housing part of the damping valve device and fluidically connects the tension main control chamber to the pilot control chamber. The main piston has, for example, a first piston region, which is adjoined in the axial direction by a second piston region with a smaller diameter than the first piston region.The first flow passage preferably extends exclusively through the first piston region of the main piston, in particular centrally and axially through it into the pilot chamber. A flow throttle in each flow passage allows separate adjustment of the flow throttling in the rebound and compression stages.

[0020] According to a further embodiment, a check valve is arranged at each of the first flow passage and the second flow passage, so that hydraulic fluid can flow exclusively in one direction through the first and second flow passages. The first flow passage preferably has a check valve arranged such that hydraulic flow from the main tension control chamber into the pilot control chamber is permitted and prevented in the opposite direction. The second flow passage preferably has a check valve arranged such that hydraulic flow from the main pressure control chamber into the pilot control chamber is permitted and prevented in the opposite direction.A check valve in each of the flow passages allows the hydraulic flows in the rebound and compression stages to be directed into the pilot chamber, so that the same pilot chamber and the connected pilot valve can be used in both the rebound and compression stages.

[0021] According to a further embodiment, the first flow passage and the second flow passage are arranged completely separately from one another. This achieves separate flow guidance in the rebound and compression stages.

[0022] According to a further embodiment, the connecting channel for fluidically connecting the pilot chamber to the pilot working chamber is formed in the main piston. The connecting channel extends, in particular, centrally and axially through the main piston from the pilot chamber into a pilot working chamber. Preferably, the connecting channel forms the fluid inlet to the pilot valve. The pilot working chamber is preferably directly connected to the connecting channel in fluidically. Preferably, the connecting channel in the main piston ensures a simple, direct fluid connection between the pilot chamber and the pilot working chamber, with the hydraulic fluid flowing axially through the pilot working chamber in the direction of the armature.

[0023] According to a further embodiment, the sliding tappet rests against the main piston in the closed position of the pilot valve in such a way that it fluidically closes the connecting channel. The main piston preferably forms a pilot valve seat against which the sliding tappet rests when the pilot valve is closed. The contact of the sliding tappet with the main piston enables follow-up control, whereby the sliding tappet directly applies a closing force to the main piston, which is applied to the sliding tappet via the armature rod. This achieves a high level of operational reliability. The pilot valve preferably comprises a sliding tappet which is arranged so as to be axially movable within the pilot working chamber. The sliding tappet preferably rests against the armature with its end facing away from the main valve, so that the movement of the armature and the sliding tappet are mechanically coupled.

[0024] According to a further embodiment, the pilot valve has a pilot spring arranged such that it applies an axial force to the sliding plunger in the direction of the armature, in particular in the opening direction of the pilot valve. The pilot spring preferably serves as a fail-safe device in the event that the coil is inadvertently de-energized. The pilot spring preferably bears against the sliding plunger and the main piston. In particular, the pilot spring is designed as a spiral spring and bears within a hollow cylindrical region of the main piston. For example, the pilot spring is supported on an annular shoulder of the sliding plunger, which points in the direction of the working chamber remote from the piston rod.

[0025] According to a further embodiment, the damping valve device has a spring element which is attached to the main piston in such a way that it applies a spring force to the main piston in the closing direction of the main valve. The spring element is preferably attached to the side of the main piston facing away from the main valve seat. In particular, the spring element is arranged in such a way that it applies a spring force to the main piston in the direction of the valve seat. The spring element is designed, for example, as a spiral spring which bears against the inner surface of a hollow cylindrical region of the main piston and is supported on an end face of the main piston facing in the direction of the drive region. The spring element preferably bears with one end against a fixed housing part of the damping valve device.

[0026] According to a further embodiment, the main piston has a closing surface that borders the pilot control chamber and is arranged such that the hydraulic pressure present in the pilot control chamber applies an axial force to the closing surface of the main piston in the closing direction of the main valve, and wherein the closing surface is designed as a shoulder in the main piston. The main piston is preferably stepped and, in particular, has a first piston region pointing in the direction of the working region remote from the piston rod, which, with its outer diameter, preferably bears in a fluid-tight manner against a fixed housing part of the damping valve device. The first piston region is preferably substantially cylindrical.The first piston region is adjoined in particular by a second cylindrical piston region, which is arranged coaxially to the first piston region and preferably has a smaller diameter than the first piston region. An annular, preferably circular disk-shaped, end face is preferably formed on the first piston region, which faces in the direction of the drive region. The end face is preferably designed as a closing surface, in particular as a first closing surface, of the main piston and borders in particular on the pilot control chamber, so that the hydraulic pressure present in the pilot control chamber acts on the main piston, in particular the closing surface of the main piston, with an axial force in the closing direction of the main valve.

[0027] An annular end face is preferably formed on the second piston region, which faces in the direction of the drive region and is particularly designed as a second closing surface of the main piston in addition to the previously described closing surface. The second closing surface borders the pilot working chamber, so that the hydraulic pressure present in the pilot working chamber acts on the second closing surface of the main piston with an axial force in the closing direction of the main valve. The entire closing surface of the main piston therefore preferably comprises the first and second closing surfaces. In particular, the size and / or position of the closing surface of the main piston is the same for a tensile or compressive load on the vibration damper. The sliding tappet is preferably arranged and designed such that hydraulic fluid can flow through the connecting channel exclusively in one flow direction.

[0028] According to a further embodiment, the main piston has a pull opening area A Z , which is directly adjacent to the train's main control room and has a pressure opening area A D which is directly adjacent to the main pressure control room and where the ratio A Z / A D between the tension opening area A Z and the pressure opening area A D 1:1 to 5:1, in particular 2:1 to 4:1, preferably 3:1.

[0029] According to a further embodiment, the damping valve device has a first pilot outflow channel for fluidically connecting the pilot working chamber to the main rebound control chamber and a second pilot outflow channel for fluidically connecting the pilot working chamber to the main compression control chamber. This enables separate outflow of hydraulic fluid from the pilot working chamber during the rebound and compression stages.

[0030] The first pilot outflow channel is preferably formed in a fixed housing part of the vibration damper and preferably extends from the pilot working chamber into the main tension control chamber. The first pilot outflow channel preferably has a check valve arranged in such a way that a hydraulic flow from the pilot working chamber into the first fluid passage, in particular the piston rod-side working chamber, is permitted and prevented in the opposite direction. The first pilot outflow channel is arranged, for example, above the sliding tappet, in particular in the tension direction.

[0031] The second pilot outflow channel is preferably designed for the fluidic connection of the pilot working chamber to the working chamber remote from the piston rod. The second pilot outflow channel is formed in particular in the main piston and preferably extends axially through it, in particular through the first and second piston regions. The second pilot outflow channel preferably extends from the pilot working chamber into the main pressure control chamber. The second pilot outflow channel preferably has a check valve arranged such that a hydraulic flow from the pilot working chamber into the working chamber remote from the piston rod is permitted and prevented in the opposite direction.

[0032] According to a further embodiment, the damping valve device comprises a comfort valve through which hydraulic fluid can flow in the compression stage and the rebound stage. In particular, the comfort valve comprises at least one comfort spring washer package, which for example comprises at least one or a plurality of spring washers that rest on a comfort valve seat. The comfort valve preferably has two spring washer packages, one designed to dampen the hydraulic fluid during a movement of the piston rod in the retraction direction and the other spring washer package designed to dampen the hydraulic fluid during a movement of the piston rod in the compression direction. The comfort valve is preferably fluidically connected directly to the working chamber remote from the piston rod. The comfort valve preferably forms the end of the working piston pointing towards the base valve.

[0033] According to a further embodiment, the damping valve device comprises a bypass channel arranged in such a way that it fluidically connects the pressure main control chamber and the tension main control chamber. The bypass channel is preferably hydraulically configured parallel to the main flow channel as a bypass of the main valve. The bypass channel extends in particular from the pressure main control chamber to the tension main control chamber and fluidically connects them.

[0034] According to a further embodiment, a check valve is arranged on the bypass channel such that hydraulic fluid can flow through the bypass channel exclusively in one direction. The bypass channel preferably has a check valve that is arranged and designed such that it allows hydraulic flow from the pressure main control chamber into the rebound main control chamber and prevents flow in the opposite direction. In the bypass channel, in particular, a throttle element is arranged hydraulically connected in series with the check valve. The damping valve device additionally has, for example, a further bypass channel, which is preferably hydraulically connected in parallel to the bypass channel and in particular has a flow throttle. Hydraulic fluid can preferably flow through the further bypass channel in the rebound and compression stages of the vibration damper.

[0035] According to a further embodiment, the sliding tappet has an opening surface which, in the closed position of the pilot valve, at least partially rests against the main piston, and wherein the opening surface has a recess. The opening surface is preferably formed on the end face of the sliding tappet facing the connecting channel and is preferably arranged such that, in the closed position of the pilot valve, it completely closes the connecting channel. The opening surface preferably has a recess pointing in the axial direction, in particular a central one, which is, for example, conical. The recess is, for example, cylindrical, with a round, circular, or polygonal cross-section. The recess preferably serves to enlarge the opening surface and thus to adjust the opening pressure of the pilot valve. Description of the drawings

[0036] The invention is explained in more detail below using several embodiments with reference to the accompanying figures. Fig. 1 shows a schematic representation of a vibration damper in a longitudinal sectional view according to an embodiment. Fig. 2 shows a schematic representation of a damping valve device of a vibration damper in the compression stage in a longitudinal sectional view according to an embodiment. Fig. 3 shows a schematic representation of a damping valve device of a vibration damper in the rebound stage in a longitudinal sectional view according to an embodiment. Fig. 4 a schematic representation of a hydraulic circuit diagram of a damping valve device according to an embodiment. Fig. 5 a schematic representation of a hydraulic circuit diagram of a damping valve device according to an embodiment. Fig. 6 a schematic representation of a hydraulic circuit diagram of a damping valve device according to an embodiment.

[0037] Fig. 1 shows a vibration damper 10, wherein the vibration damper 10 is a multi-tube vibration damper, for example a two-tube vibration damper. The vibration damper 10 has an outer tube 12, which forms an outer surface, in particular a housing, of the vibration damper 10. An inner tube 14, which can also be referred to as a damper tube, is arranged coaxially within the outer tube 12. A compensation chamber 16 is formed between the outer tube 12 and the inner tube 14, which is preferably at least partially filled with a hydraulic fluid. For example, the compensation chamber 16 is partially filled with a gas.

[0038] Within the inner tube 14, a working piston 18 connected to a piston rod 20 is arranged such that it is movable within the inner tube 14, wherein the inner tube is preferably designed as a guide for the working piston 18. The working piston 18 has a damping valve device 54. The working piston 18 divides the interior of the inner tube 14 into a first working chamber 22, which is arranged on the piston rod side, and a second working chamber 24, which is arranged remote from the piston rod.

[0039] The interior of the outer tube 12 is fluidically sealed on the piston rod side by means of a closure assembly 34. Opposite the closure assembly 34, at the end remote from the piston rod, the interior of the outer tube 12 is fluidically sealed by means of a base piece 36. A base valve 38, for example, is arranged on the base piece 36 and is attached in particular to the end of the inner tube 14 remote from the piston rod. The base valve 38 is, for example, a check valve through which flow can occur in both directions or only in one direction. The second working chamber 24 is preferably fluidically connected to the compensation chamber 16 via the base valve 38. The piston rod-side end of the inner tube 14 and the outer tube 12 is preferably attached to the closure assembly 34.

[0040] The piston rod 20 has, for example, an optional pull stop which is subjected to a spring force via a spring element 42 during a movement in the pulling direction Z.

[0041] Fig. 2 shows an exemplary damping valve device 54, which is preferably arranged in the working piston 18 of the vibration damper 10. The damping valve device 54 is designed, for example, as a pilot-operated pressure relief valve and comprises a preferably cylindrical damping valve housing, which, for example, has a substantially tubular tube part 45 and a housing upper part 44, which is formed, for example, integrally with the tube part 45. The piston rod 20 is preferably attached to the housing upper part 44. The housing upper part 44 has, for example, a connection area (not shown), which has one or more connection contacts for an electrical power supply to the damping valve device 54. The connection contacts for an electrical power supply are preferably connected to a drive unit.

[0042] The damping valve device 54 has, for example, a drive region 48 and a valve region 50. The drive region 48 is arranged, for example, in the upper region of the damping valve device 54 facing the piston rod 20 and preferably substantially above, in particular in the pulling direction Z, the valve region 50. The drive region 48 preferably comprises a drive designed as an electromagnet. The electromagnet comprises a coil 52 with a plurality of windings made of a current-conducting wire. The coil 52 is preferably arranged within the tubular part 45 and concentrically thereto. For example, the coil 52 bears against the inner wall of the tubular part 45. A cover section 56 is arranged, for example, axially between the coil 52 and the upper housing part 44. The coil 52 preferably bears against the cover section 56 and is in particular fastened thereto.The cover section 56 is made, for example, from a metal, in particular a magnetic material, preferably a material with low magnetic resistance. The coil 52 comprises, for example, a coil carrier onto which the windings of the coil are wound. The coil 52 at least partially or completely encloses an armature chamber 60 that extends centrally in the axial direction. An armature 62 is mounted for axial movement within the armature chamber 60. The armature 62 is preferably cylindrical and has a diameter that is slightly smaller than the diameter of the armature chamber 60, such that the armature 62 is preferably mounted so as to be slidable in the axial direction. For example, the armature 62 comprises a central armature rod 65, which, for example, has a round cross-section and extends centrally in the axial direction through the armature chamber 60.The armature chamber 60 is preferably defined by an at least partially hollow-cylindrical pole tube 64. The pole tube 64 preferably has a bottom and is open, in particular, toward the valve region 50. The pole tube 64 is preferably formed from a magnetizable or magnetic material and has, for example, a magnetic separation 58.

[0043] Coil 52 is preferably designed and arranged such that, when energized, it creates a magnetic field having magnetic field lines that preferably extend substantially axially within armature chamber 60. Armature 62 is preferably formed from a magnetizable or magnetic material and is movable in the axial direction according to the magnetic field created by coil 52.

[0044] Adjacent to the hollow cylindrical region of the pole tube 64 in the axial direction and coaxially therewith is a pole tube element, which together form the pole tube 64, wherein the pole tube 64 is in particular designed in multiple parts, in one piece or in one part. The pole tube 64 has an upper tubular region with in particular a constant inner diameter, which is preferably designed as a hollow cylinder and extends, for example, from the cover section 56 in the axial direction up to beyond the armature 62. Adjacent to the upper hollow cylindrical region in the axial direction is a lower region with an enlarged diameter, wherein the outer surface of the pole tube 64 preferably extends up to the tubular part 45 and at least partially bears against it and is sealed fluid-tight to the tubular part 45, for example by a sealing element.The pipe part 45 encloses at least partially or completely in the axial and circumferential directions a valve region 50, which will be explained in more detail in one of the following sections.

[0045] The valve region 50 comprises, for example, a main valve 68 and a pilot valve 70. The damping valve device 54 arranged in the working piston 18 preferably has exactly one main valve 68 and / or exactly one pilot valve 70. Hydraulic fluid can preferably flow through the main valve 68 and / or the pilot valve 70 when the piston rod 20 moves in the pulling direction Z and in the pushing direction D. A seal 26, such as a sealing ring, is preferably attached to the working piston 18 and seals the working piston 18 in a fluid-tight manner to the damper tube 14. The seal 26 preferably bears fluid-tight against the outer surface of the working piston 18 and against the inner surface of the damper tube 14. The damping valve device 54 further optionally has a comfort valve 28. The comfort valve 28 is preferably designed so that hydraulic fluid can flow through it in both the pushing direction D and the pulling direction Z.In particular, the comfort valve comprises at least one comfort spring washer assembly, which, for example, comprises at least one or a plurality of spring washers resting on a comfort valve seat. The comfort valve 28 preferably has two spring washer assemblies, one of which is designed to dampen the hydraulic fluid during a movement of the piston rod 20 in the pulling direction Z and the other spring washer assembly is designed to dampen the hydraulic fluid during a movement of the piston rod 20 in the pushing direction D. The comfort valve 28 is preferably fluidically connected directly to the working chamber 24 remote from the piston rod. The comfort valve 28 is preferably arranged in the working chamber 24 remote from the piston rod and, in particular, forms the end of the working piston 18 pointing in the direction of the base valve 36.The comfort valve 28 comprises, for example, a comfort valve housing 32, which is preferably separate from the tubular part 45 and firmly connected thereto or formed integrally with the tubular part 45. For example, the comfort valve housing 32 has a larger outer diameter than the tubular part 45. Preferably, the seal 26 is attached to the comfort valve housing 42 and connected thereto in a fluid-tight manner. The comfort valve housing 32 preferably encloses the comfort spring washer packs 30 axially and circumferentially.

[0046] The working piston 18 comprises a first fluid passage 39 to the first working chamber 22, wherein the first fluid passage 39 is formed, for example, in the tubular part 45, for example as a circular opening. The damping valve device 54 is preferably fluidically connected to the first, piston rod-side, working chamber 22 via the first fluid passage 39. The first fluid passage 39 is designed, for example, as a fluid inlet for admitting hydraulic fluid into the damping valve device 54 during a movement of the piston rod 20 in the pulling direction Z, and as a fluid outlet for discharging hydraulic fluid from the damping valve device 54 during a movement of the piston rod in the pushing direction D.

[0047] The working piston 18, in particular the comfort valve 28, preferably has a second fluid passage 40 to the second working chamber 24, via which the damping valve device 54 is preferably fluidically connected to the second working chamber 24 remote from the piston rod. The second fluid passage 40 is designed, for example, as a fluid inlet for admitting hydraulic fluid into the comfort valve 28 and the main valve 68 when the piston rod 20 moves in the compression direction D, and as a fluid outlet for discharging hydraulic fluid from the comfort valve 28 and the main valve 68 when the piston rod moves in the tension direction Z.

[0048] During operation of the damping valve device 54, upon piston rod movement in the pulling direction Z, the hydraulic fluid flows, preferably from the first fluid passage 39 into the main valve 68, and into the pilot valve 70 and subsequently optionally through the comfort valve 28 and to the second fluid passage 40. The main valve 68 comprises a main piston 76, which is arranged to be axially movable within a main working chamber 78. The main valve 68 also comprises, for example, a housing part 80, which at least partially delimits the main working chamber 78 and forms an axial guide for the main piston 76. The housing part 80 is arranged, for example, coaxial with and within the tubular part 45. A gap, in particular an annular space, is preferably formed between the housing part 80 and the tubular part 45. The main piston 76 is preferably arranged within the housing part 80 and concentrically thereto.The main piston 76 preferably divides the main working chamber 78 into a pressure main control chamber 82a, a tension main control chamber 82b, and a pilot control chamber 84. The main piston 76 has, in particular, a first flow passage 86a, which extends through the main piston 76 and forms a fluidic connection between the pressure main control chamber 82a and the pilot control chamber 84. For example, the first flow passage 86a extends centrally and in the axial direction through the main piston 76. The housing part 80 has, for example, a second flow passage 86b, which forms a fluidic connection between the tension main control chamber 82b and the pilot control chamber 84. The second flow passage 86b is arranged, for example, at the same height as the first fluid passage 39. The first and second flow passages 86a,b preferably each have a respective flow throttle 96a,b, in particular a cross-sectional constriction.

[0049] The pressure main control chamber 82a is formed, for example, between the comfort valve 28 and the main piston 76. The rebound main control chamber 82b is preferably formed between the housing part 80 and the tubular part 45 as the previously described gap, in particular an annular chamber. The hydraulic pressure of the second working chamber 24, remote from the piston rod, is preferably present in the pressure main control chamber 82a, while the pressure of the first working chamber 22, on the piston rod side, is preferably present in the rebound main control chamber 82b.

[0050] A guide element 72 is arranged, preferably in a fixed position, in the damping valve device 54 between the main valve 68 and the comfort valve 28. The guide element 72 is, for example, tubular and serves to conduct hydraulic fluid from the comfort valve 28 to the main valve 68. For example, the guide element 72 at least partially forms the main pressure control chamber 82a. The guide element 72 is preferably directly or indirectly connected to the tubular part 45 and is arranged in a fixed position relative thereto. A main valve seat 90 is preferably formed on the guide element 72. For example, a spring assembly 77 is attached to the main piston 76, which spring assembly rests against the main valve seat 90 of the guide element 72 when the main valve 68 is in the closed position. The spring assembly 77 preferably comprises a plurality of, in particular two, spring washers that are arranged coaxially to one another and preferably rest against one another.The spring washer of the spring assembly 77 pointing in the direction of the main pressure control chamber 82a preferably rests against the main valve seat 90 and in particular has a bypass opening 74.

[0051] In the open position of the main valve 68, in which the main piston 76 is moved axially away from the main valve seat 90, the main piston 76 and the spring assembly 77 are lifted from the main valve seat 90, so that a main flow channel 92 is formed between the main piston 76 and the main valve seat 90. The main flow channel 92 forms a fluid connection between the first and second working chambers 22, 24. In particular, the main flow channel 92 forms a fluid connection between the pressure main control chamber 82a and the tension main control chamber 82b. Optionally, the damping valve device 54 has a bypass channel 88, which is preferably hydraulically designed parallel to the main flow channel 92 as a bypass of the main valve 68. The bypass channel 88 extends, for example, from the pressure main control chamber 82a to the tension main control chamber 82b and connects them fluidically.Preferably, the bypass channel 88 has a check valve arranged and configured to allow hydraulic flow from the pressure main control chamber 82a into the tension main control chamber 82b and prevent it in the opposite direction.

[0052] The main piston 76 is preferably stepped and has, for example, a first piston region 113 pointing in the direction of the working region 24 remote from the piston rod, which bears fluid-tight with its outer diameter against the housing part 80. The first piston region 113 is, for example, essentially cylindrical. Adjoining the first piston region 113 is a second cylindrical piston region 114, which is arranged coaxially to the first piston region 113 and has a smaller diameter than the first piston region 113. On the main piston 76, in particular on the first piston region 113, an annular end face 46 is preferably formed, which points in the direction of the drive region 48. The end face 46 serves as a closing surface A Sof the main piston 76 and borders on the pilot control chamber 84, so that the hydraulic pressure present in the pilot control chamber 84 acts on the main piston 76, in particular the closing surface 46 of the main piston 76, with an axial force in the closing direction of the main valve. The pilot control chamber 84 is preferably delimited by the closing surface 46, the housing part 80 and the main piston 76, in particular the second region of the main piston 76. The first flow passage 86a for connecting the pressure main control chamber 82a preferably extends exclusively through the first region of the main piston 76, in particular centrally and in the axial direction through it into the pilot control chamber 84. The first flow passage 86a preferably has a check valve which is arranged in such a way that a hydraulic flow from the pressure main control chamber 82a into the pilot control chamber 84 is enabled and prevented in the opposite direction.The second flow passage 86b preferably also has a check valve arranged to allow hydraulic flow from the main train control chamber 82b into the pilot control chamber 84 and prevent flow in the opposite direction.

[0053] On the main piston 76, in particular on the second piston region 114, there is preferably an annular end face A SP which points in the direction of the drive area 48. The end face A SP serves in addition to the closing surface As as a further, in particular second, closing surface A SP of the main piston 76 and borders on the pilot working chamber 100, so that the hydraulic pressure present in the pilot working chamber 100, the main piston 76, in particular the closing surface A SP of the main piston 76, is subjected to an axial force in the closing direction of the main valve 68.

[0054] On the side of the main piston 76 facing away from the main valve seat 90, a spring element 94 is attached, which is arranged such that it applies a spring force to the main piston 76 in the direction of the valve seat 90. The spring element 94 is, for example, a spiral spring that bears against the inner surface of a hollow cylindrical region of the housing part 80 and is supported with one end on the end face 46, in particular the closing surface As, of the main piston 76 facing in the direction of the drive region 48. The spring element 94 is preferably supported with the other end on the housing part 80. For example, the housing part has a groove in which the spring element 94 is arranged.

[0055] A connecting channel 98 is preferably formed in the main piston 76, which extends, in particular, centrally and in the axial direction through it from the pilot control chamber 84 into a pilot working chamber 100. The connecting channel 98 preferably forms the fluid inlet into the pilot valve 70. The region of the main piston 76 facing in the direction of the drive region 48 is, for example, hollow-cylindrical in shape, with the interior of the hollow-cylindrical region preferably at least partially forming the pilot working chamber 100. The pilot working chamber 100 is preferably fluidically connected directly to the connecting channel 98.

[0056] The pilot valve 70 comprises, for example, a sliding plunger 102, which is arranged for axial movement within the pilot working chamber 100. The sliding plunger 102 preferably bears against the armature 62, in particular the armature rod 65, with its end facing away from the main valve 68, so that the movement of the armature 62 and the sliding plunger 102 are coupled, at least during the movement of the armature 62 in the direction of the sliding plunger 102. In a closed position of the pilot valve 70, the sliding plunger 102 preferably bears against the main piston 76 such that the connecting channel 98 is completely closed by the sliding plunger 102. In an open position of the pilot valve 70, the sliding plunger 102 is lifted from the main piston 76, so that the connecting channel 98 is opened by the sliding plunger 102 and a fluid flow occurs between the pilot control chamber 84 of the main valve 68 and the pilot working chamber 100.The sliding plunger 102 is preferably mounted so as to be axially movable relative to the main piston 76. In particular, the sliding plunger 102 is guided axially by the main piston 76 and preferably rests against the inner wall of the hollow cylindrical portion of the main piston 76, particularly in a fluid-tight manner.

[0057] The sliding plunger 102 has, for example, a T-shaped longitudinal section, wherein the sliding plunger 102 has a first region facing the connecting channel 98 with a cross-section that is larger than the cross-section of the connecting channel 98, and a second region facing the armature 62 with a larger cross-section than the first region. The second region preferably extends over the entire cross-section of the pilot working chamber 100.

[0058] In the closed position, the sliding tappet 102 preferably rests against a first valve seat formed in the main piston 76. The sliding tappet 102 of the pilot valve 70 preferably has at least one or a plurality of passage bores 112 that extend axially through the sliding tappet 102 and form a flow channel for hydraulic fluid through the sliding tappet 102. The flow passages 112 and in particular the pilot working chamber 100 are preferably fluidically connected to the first fluid passage 39 and the second fluid passage 40.

[0059] The pilot valve 70 preferably has a pilot spring 108 arranged such that it applies an axial force to the sliding plunger 102 in the direction of the armature 62, in particular in the opening direction of the pilot valve 70. The pilot spring 108 preferably serves as a fail-safe device in the event that the coil is de-energized and is designed such that the hydraulic fluid flows out via the pilot outflow channel 104a and in particular a fail-safe valve arranged therein. The pilot spring preferably bears against the sliding plunger 102 and the main piston 76. In particular, the pilot spring 108 is designed as a spool spring and bears within the hollow cylindrical region of the main piston 76. For example, the pilot spring 102 is supported on an annular shoulder of the sliding plunger 102, which points in the direction of the working chamber 24 remote from the piston rod.

[0060] The sliding tappet 102 preferably has an opening surface 110, which is formed on the first region of the sliding tappet facing the connecting channel 98 and is arranged such that it closes the connecting channel 98 in the closed position of the pilot valve 70. The opening surface 110 is also referred to, for example, as the pilot opening surface A P and preferably has an axially directed, in particular central, recess, which is, for example, conical. The recess can, for example, be cylindrical, with a round, circular, or angular cross-section. The recess preferably serves to enlarge the opening area and thus to adjust the opening pressure of the pilot valve 70.

[0061] The pilot valve 70 preferably comprises a first pilot outflow channel 104a, which is designed and arranged for the fluidic connection of the pilot working chamber 100 to the first fluid passage 39, preferably the piston rod-side working chamber 22. The first pilot outflow channel 104a is formed, for example, in the housing part 80, in particular in a housing element 106 firmly connected thereto, and preferably extends from the pilot working chamber 100 into the main train control chamber 82b. The first pilot outflow channel 104a preferably has a check valve arranged such that a hydraulic flow from the pilot working chamber 100 into the first fluid passage 39 is enabled and prevented in the opposite direction.

[0062] The pilot valve 70 preferably comprises a second pilot outflow channel 104b, which is designed and arranged for the fluidic connection of the pilot working chamber 100 to the second fluid passage 40, preferably the working chamber 24 remote from the piston rod. The second pilot outflow channel 104b is formed, for example, in the main piston 76 and preferably extends axially therethrough, in particular through the first and second piston regions. The second pilot outflow channel 104b preferably extends from the pilot working chamber 100 into the main pressure control chamber 82a. The second pilot outflow channel 104b preferably has a check valve arranged such that a hydraulic flow from the pilot working chamber 100 into the second fluid passage 40 is enabled and prevented in the opposite direction.

[0063] During operation of the damping valve device 54, upon movement of the piston rod 20 in the pressure direction D, the hydraulic fluid flows through the second fluid passage 40 into the optional comfort valve 28, into the pressure main control chamber 82a. The pressure in the pressure main control chamber 82a applies an opening force to the main piston 76, causing it to move axially upward. The main piston 76 lifts off the main valve seat 90, and the hydraulic fluid flows through the main flow channel 92 to the rebound main control chamber 82b, in particular the second fluid passage 39. At the same time, a partial flow of the hydraulic fluid flows through the first flow passage 86a in the main piston 76 to the pilot control chamber 84, applying a closing force to the main piston 76 in the direction of the main valve seat 90.The closing force determines the opening width of the main valve 68, in particular the cross-section of the main flow channel 92, which determines the damping force of the damping valve device 54. The pressure in the pilot control chamber 84 is adjusted by the pilot valve 70, with the hydraulic fluid flowing from the pilot control chamber 84 through the connecting channel 98 into the pilot working chamber 100, which is opened by the sliding tappet 102. The opening width of the connecting channel 98 depends on the axial position of the sliding tappet 102, which is adjusted, in particular predetermined, by means of a solenoid coil 54.In the closed position of the pilot valve 70, the sliding tappet 102 preferably completely closes the connecting channel 98, so that the hydraulic pressure in the pilot control chamber 84 rises to a maximum value and the main valve 68 is closed and preferably subjected to a force in the closing direction by pressing the main piston 76 onto the main valve seat 90. In an open position of the pilot valve 70, the connecting channel 98 is at least partially opened by the sliding tappet 102, so that a hydraulic flow flows through the passage bores 112 in the sliding tappet 102 and flows via a first pilot outflow channel 104a arranged downstream of the passage bores 112 to the main traction control chamber 82b, in particular the second fluid passage 39. A further partial flow optionally flows through the bypass channel 88, which fluidically connects the pressure main control chamber 82a with the tension main control chamber 82b.The fluid flow when the piston rod 20 moves in the pressure direction D is in . Fig. 2 is schematically represented by the arrows, wherein the solid line represents the main flow through the main valve 68 and the broken line represents the pilot flow through the pilot valve 70 and the bypass flow through the bypass channel 88.

[0064] Fig. 3 shows the damping valve device 54 of the Fig. 2, wherein the fluid flow is shown during a movement of the piston rod in the pulling direction. The main piston 76 preferably has a pulling opening area A Z and a pressure opening area A D The pressure opening area A D is the area of ​​the main piston 76 directly adjacent to the pressure main control chamber 82a, whereby the pull opening area A Z the area of ​​the main piston 76 directly adjacent to the main control chamber 82b. The ratio (A Z / A D ) between the tension opening area AZ and the pressure opening area A D is for example 1:1 to 5:1, in particular 2:1 to 4:1, preferably 3:1.

[0065] Fig. Figure 4 shows a hydraulic circuit diagram of a damping valve device 54, wherein the solid lines represent the main volume flow and the broken lines the pilot flow. The working chambers 22, 24 of the vibration damper 54 are fluidically connected to one another via the main volume flow flowing through the main valve 68 of the damping valve device 54. The pilot valve 70 is preferably hydraulically connected in parallel to the main valve 68. In particular, the pilot valve 70 is designed such that it Sof the main piston 76, in particular depending on the position of the sliding tappet 102 of the pilot valve 70. The working chamber 24 remote from the piston rod is preferably fluidically connected to the pilot valve 70 via the first flow passage 86a, for example via a flow throttle 96a and a check valve. The working chamber 22 on the piston rod side is preferably fluidically connected to the pilot valve 70 via the second flow passage 86b, for example via a flow throttle 96b and a check valve.

[0066] Fig. Figure 5 shows another example of a hydraulic circuit diagram of a damping valve device 54, which is essentially the same as that of Fig. 4, wherein a bypass channel 88 is additionally arranged between the working chamber 24 remote from the piston rod and the working chamber 22 on the piston rod side. For example, a throttle element and a check valve are arranged hydraulically connected in series in the bypass channel 88, so that hydraulic fluid can flow through the bypass channel 88 exclusively in one direction, namely from the working chamber 24 remote from the piston rod into the working chamber 22 on the piston rod side. The bypass channel 88 is preferably arranged hydraulically parallel to the pilot valve 70 and / or the main valve 68.

[0067] Fig. Figure 6 shows another example of a hydraulic circuit diagram of a damping valve device 54, which is essentially the same as that of Fig. 4 or Fig.5, wherein the damping valve device 54 additionally has a further bypass channel 116, which is preferably hydraulically connected in parallel to the bypass channel 88 and, in particular, has a flow restrictor. Hydraulic fluid can preferably flow through the further bypass channel 116 during the rebound and compression stages of the vibration damper 10. List of reference symbols 10 vibration dampers 12 Outer tube 14 inner tube 16 Compensation room 18 working pistons 20 piston rod 22 first / piston rod side working chamber 24 second / piston rod remote working chamber 26 Seal 28 Comfort valve 30 comfort spring washer package 32 comfort valve housing 34 closure package 36 floor pieces 38 bottom valve 39 first fluid passage to the first working chamber 22 40 second fluid passage to the second working chamber 24 42 spring element 44 Upper case 45 Pipe part 46 Front face / closing face 48 drive range 50 valve range 52 coil 54 Damping valve device 56 lid section 58 magnetic separation 60 anchor room 62 anchors 64 Pole tube 65 anchor rod 68 Main valve 70 Pilot valve 72 Guide element 74 Bypass opening 76 main pistons 77 spring package 78 Main workroom 80 Housing part 82a,b Main control room for tension / compression 84 Pre-control room 86a,b flow passage 88 Bypass channel 90 Main valve seat 92 Main flow channel 94 spring element 96a,b Flow restrictor 98 connecting channel 100 pilot workspace 102 sliding tappets 104a first pilot outflow channel 104b second pilot outflow channel 106 Housing element 108 pilot spring 110 Opening area of ​​the sliding tappet 112 through hole 113 first piston area 114 second piston area 116 additional bypass channel A S first closing surface of the main piston 76 A D Pressure opening area of ​​the main piston 76 A Z Main piston opening area 76 A SP second closing surface of the main piston 76 QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 215 480 A1

[0002]

Claims

[1] Vibration damper (10) of a motor vehicle, an outer tube (12) and an inner tube (14) arranged coaxially thereto and a working piston (18) arranged axially movable within the inner tube (14), which divides the interior of the inner tube (14) into a working chamber (22) on the piston rod side and a working chamber (24) remote from the piston rod, a damping valve device (54) arranged in the working piston (18), the damping valve device (54) comprising: a coil (52), an axially movable armature (62) arranged at least partially within the coil (52), a main valve (68) with a main piston (76) which separates a pressure main control chamber (82a), a tension main control chamber (82b) and a pilot control chamber (84) from each other, a pilot valve (70) which is designed such that it can be flowed through by hydraulic fluid in the rebound stage and in the compression stage, with a pilot working chamber (100) and a sliding tappet (102) arranged in the pilot working chamber (100) which is axially movable by means of the armature (62), and a connecting channel (98) which is arranged between the pilot control chamber (84) and the pilot working chamber (100) and fluidically connects them, characterized by , that the pressure main control chamber (82a) is fluidically connected to the pilot control chamber (84) via a first flow passage (86a) and the tension main control chamber (82b) is fluidically connected to the pilot control chamber (84) via a second flow passage (86b). [2] Vibration damper (10) according to claim 1, wherein a flow throttle (96a,b) is arranged in each of the first flow passage (86a) and the second flow passage (86b). [3] Vibration damper (10) according to one of the preceding claims, wherein a check valve is arranged at each of the first flow passage (86a) and the second flow passage (86b), so that hydraulic fluid can flow through the first and the second flow passage (86a,b) exclusively in one direction. [4] Vibration damper (10) according to one of the preceding claims, wherein the first flow passage (86a) and the second flow passage (86b) are arranged separately from each other. [5] Vibration damper (10) according to one of the preceding claims, wherein the connecting channel (98) is formed in the main piston (76) for fluidically connecting the pilot control chamber (84) to the pilot working chamber (100). [6] Vibration damper (10) according to claim 5, wherein the sliding tappet (102) in the closed position of the pilot valve (70) bears against the main piston (76) in such a way that it fluidically closes the connecting channel (98). [7] Vibration damper (10) according to one of the preceding claims, wherein the pilot valve (70) has a pilot spring (108) arranged to apply an axial force to the sliding plunger (102) in the direction of the armature (62). [8] Vibration damper (10) according to one of the preceding claims, wherein the damping valve device (54) comprises a spring element (94) which is attached to the main piston (76) in such a way that it applies a spring force to the main piston (76) in the closing direction of the main valve (68). [9] Vibration damper (10) according to one of the preceding claims, wherein the main piston (76) has a closing surface (A S) which is adjacent to the pilot control chamber (84) and is arranged such that the hydraulic pressure present in the pilot control chamber (84) closes the closing surface (A S ) of the main piston (76) is subjected to an axial force in the closing direction of the main valve (68) and wherein the closing surface (A S ) is formed as a shoulder in the main piston (76). [10] Vibration damper (10) according to one of the preceding claims, wherein the main piston (76) has a tension opening area (A Z ), which is directly adjacent to the train main control room (82b) and has a pressure opening area (A D ) which is directly adjacent to the main pressure control chamber (82a) and wherein the ratio (A Z / A D ) between the pull opening area (A Z ) and the pressure opening area (A D ) 1:1 to 5:1, in particular 2:1 to 4:1, preferably 3:

1. [11] Vibration damper (10) according to one of the preceding claims, wherein the damping valve device (54) has a first pilot outflow channel (104a) for fluidically connecting the pilot working chamber (100) to the main tension control chamber (82b) and a second pilot outflow channel (104b) for fluidically connecting the pilot working chamber (100) to the main pressure control chamber (82a) [12] Vibration damper (10) according to one of the preceding claims, wherein the damping valve device (54) comprises a comfort valve (28) through which hydraulic fluid can flow in the compression stage and in the rebound stage. [13] Vibration damper (10) according to one of the preceding claims, wherein the damping valve device (54) comprises a bypass channel (88) arranged to fluidically connect the pressure main control chamber (82a) and the tension main control chamber (82b). [14] Vibration damper (10) according to claim 13, wherein a check valve is arranged on the bypass channel (88) such that the bypass channel (88) can be flowed through by hydraulic fluid exclusively in one direction. [15] Vibration damper (10) according to one of the preceding claims, wherein the sliding tappet (102) has an opening area (A P ) which, in the closed position of the pilot valve (70), at least partially bears against the main piston (76) and wherein the opening area (A P ) has a recess.

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