Damping valve device for motor vehicle shock absorber

Abstract

The invention relates to a vibration damper for a motor vehicle, comprising an outer tube and an inner tube, and a working piston, a damping valve device arranged in the working piston, the damping valve device comprising a coil, an axially movable armature arranged at least partially within the coil, a main valve arranged in the coil, and a piston arranged in the main valve. The invention relates to a hydraulic system comprising a main valve, which has a main piston separating a compression main control chamber, a traction main control chamber and a pilot control chamber from one another, a pilot valve, which is designed such that a hydraulic fluid flow can pass through the pilot valve during a traction phase and a compression phase, and which has a pilot working chamber and a sliding tappet, the invention relates to a pilot valve having a pilot control chamber, a pilot working chamber, a sliding tappet arranged in the pilot working chamber and movable in the axial direction by means of the armature, and a connecting duct arranged between the pilot control chamber and the pilot working chamber.

Description

Technical Field

[0001] The invention relates to a damping valve arrangement for a motor vehicle shock absorber, wherein the damping valve arrangement comprises a main valve and a pilot valve. Background Art

[0002] DE 10 2020 215 480 A1 discloses a vibration damper having a damping valve arrangement with a pilot valve adjustable by a solenoid valve. Unstable behavior of the damping valve can occur, particularly during dynamic operation of the vibration damper, when the main valve opens and closes. Acoustic problems can also arise during the switching of the main valve. Furthermore, the damping valve arrangement is relatively large and therefore requires a large amount of installation space. Summary of the Invention

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

[0004] According to the invention, this object is achieved by a vibration damper having a damping valve arrangement having the features of independent device claim 1. Advantageous developments can be found in the dependent claims.

[0005] According to a first aspect, a vibration damper for a motor vehicle includes: an outer tube and an inner tube, the outer tube being coaxial with the inner tube; and a working piston configured to be axially movable within the inner tube and dividing the interior of the inner tube into a piston rod proximal working chamber and a piston rod distal working chamber. The vibration damper also includes a damping valve arrangement disposed within the working piston, wherein the damping valve arrangement includes a coil and an axially movable armature, the armature being at least partially disposed within the coil. The damping valve arrangement also includes a main valve having a main piston that fluidically separates a compression main control chamber, a traction main control chamber, and a pilot control chamber from one another. Furthermore, the damping valve arrangement includes a pilot valve designed and arranged to allow hydraulic fluid to flow through the pilot valve during both traction and compression phases, and the pilot valve includes a pilot working chamber and a sliding tappet disposed within the pilot working chamber and axially movable by means of the armature. The damping valve device also includes a connecting conduit that is provided between the pilot control chamber and the pilot working chamber and fluidically connects the pilot control chamber and the pilot working chamber to each other. The compression main control chamber is fluidically connected to the pilot control chamber via a first flow channel, and the traction main control chamber is fluidically connected to the pilot control chamber via a second flow channel.

[0006] Providing first and second flow passages for connecting the main control chamber to the pilot control chamber ensures fluid flow through the pilot valve during both the compression and traction phases of the vibration damper. The compression main control chamber and the traction main control chamber are each fluidly connected to the pilot control chamber.

[0007] The damping valve arrangement is, for example, a pressure-controlled valve, which can preferably be pilot-controlled. A main valve having a main piston is preferably designed for closing and opening the damping valve arrangement, in particular the pressure-controlled valve. The main piston is preferably axially movable by means of an armature and / or the hydraulic pressure prevailing in a pilot control chamber.

[0008] In addition to the main valve, the damping valve device designed as a pilot-controlled pressure control valve preferably also includes: a pilot valve having a pilot working chamber and a sliding tappet, which is arranged in the pilot working chamber and can be moved axially by means of an armature; and a connecting pipe, which is arranged between the pilot control chamber and the pilot working chamber and fluidly connects the pilot control chamber and the pilot working chamber to each other.

[0009] For example, a damping valve device is provided in a vibration damper of a motor vehicle. The vibration damper is, for example, a single-tube vibration damper or a multi-tube vibration damper, such as a twin-tube vibration damper. For example, the vibration damper includes an outer tube, which forms the outer surface of the vibration damper, in particular the housing. An inner tube, also known as the damper tube, is disposed within the outer tube and coaxially with the outer tube. A compensating chamber is formed between the outer and inner tubes. Preferably, the compensating chamber is at least partially filled with a hydraulic fluid. For example, the compensating chamber is partially filled with gas.

[0010] The working piston is connected to the piston rod and is preferably disposed within an inner tube, allowing it to move within the inner tube. The inner tube is preferably designed to serve as a guide for the working piston. For example, a damping valve arrangement may be provided on the working piston. The working piston divides the interior of the inner tube into a first piston rod proximal working chamber and a second piston rod distal working chamber.

[0011] The vibration damper preferably has a closure package that provides a fluid-tight seal against the interior of the outer tube proximally on the piston rod. Opposite the closure package, the interior of the outer tube at the distal end of the piston rod is preferably fluid-tightened by means of a base component. Specifically, the base component includes a base valve that is attached to the inner tube at the distal end of the piston rod.

[0012] The damping valve arrangement comprises a preferably cylindrical damping valve housing having a substantially tubular tube portion and an upper housing portion that is attached to the tube portion or formed integrally therewith. For example, the tube portion has a connection region with one or more connection contacts for supplying power to the damping valve arrangement. The connection contacts for the current supply are preferably connected to a drive unit.

[0013] The damping valve device preferably has a drive element designed as a solenoid, in particular a coil having a plurality of windings made of electrical conductors. The coil is preferably arranged in a housing of the damping valve device and, for example, comprises a coil carrier on which the windings of the coil are wound. Preferably, the coil at least partially or completely surrounds an armature space extending centrally in the axial direction. The armature is preferably mounted so as to be able to move axially in the armature space. The armature is preferably attached so as to be able to slide in the axial direction in the armature space and, for example, comprises a central armature rod, which, for example, has a tubular design and extends centrally in the axial direction through the armature space. 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 arrangement preferably comprises a main valve and a pilot valve. The pilot valve is preferably arranged behind the main valve in the flow direction, both in the compression phase and the traction phase of the vibration damper. Specifically, the hydraulic fluid can flow through the damping valve arrangement in both directions. Preferably, the damping valve arrangement arranged in the working piston has exactly one main valve and / or exactly one pilot valve. For example, a seal, in particular a sealing ring, is attached to the working piston, which seals the working piston relative to the damper tube in a fluid-tight manner. The working piston preferably comprises a first fluid channel leading to a proximal working chamber of the piston rod. The damping valve arrangement is preferably fluidically connected to the proximal working chamber of the piston rod via the first fluid channel. For example, when the piston rod moves in the traction direction, the first fluid channel is designed as a fluid inlet to allow hydraulic fluid to enter the damping valve arrangement; when the piston rod moves in the compression direction, the first fluid channel is designed as a fluid outlet to allow hydraulic fluid to flow out of the damping valve arrangement. The working piston preferably has a second fluid passage leading to a working chamber distal to the piston rod. The damping valve device is preferably fluidically connected to the second piston rod distal working chamber via this passage. When the piston rod moves in a compression direction, the second fluid passage is preferably designed as a fluid inlet to allow hydraulic fluid to enter the optional comfort valve and / or the main valve. When the piston rod moves in a traction direction, the second fluid passage is designed as a fluid outlet to allow hydraulic fluid to flow out of the optional comfort valve and / or the main valve.

[0015] The main valve preferably includes a main piston configured to move axially within a main working chamber. The main valve optionally includes a housing portion that at least partially delimits the main working chamber and forms an axial guide for the main piston. The main piston is preferably configured to fluidically separate a compression main control chamber, a traction main control chamber, and a pilot control chamber from one another. A main control chamber can be understood as a hydraulic space that is preferably directly connected to the main piston and impacts the main piston with a hydraulic pressure acting in the opening direction of the main valve. The main valve, which can be traversed by fluid during both the traction and compression phases, preferably has a compression main control chamber and a traction main control chamber. The compression main control chamber is designed and configured such that during the compression phase, the compression main control chamber impacts the main piston with a hydraulic pressure acting in the opening direction, while the traction main control chamber is designed and configured such that during the traction phase, the traction main control chamber impacts the main piston with a hydraulic pressure acting in the opening direction. The main valve preferably has a main valve seat, wherein in the open position of the main valve, a main flow channel is formed between the main piston and the main valve seat. The traction main control chamber and the compression main control chamber are preferably fluidically connected to each other via a main flow conduit. The hydraulic pressure of the piston rod distal working chamber is preferably applied to the compression main control chamber, wherein the hydraulic pressure of the piston rod proximal working chamber is preferably applied to the traction main control chamber.

[0016] The main valve seat is preferably formed on a guide element that is attached to the damping device in a fixed manner, with the primary piston being movable relative to the guide element. The spring assembly, which abuts the main valve seat of the guide element in the closed position of the main valve, is specifically attached to the main piston. The spring assembly preferably comprises a plurality of, in particular two, spring discs that are coaxially arranged relative to one another and preferably abut one another. The spring disc of the spring assembly that points in the direction of compression of the main control chamber preferably abuts the main valve seat and specifically has a bypass opening.

[0017] The pilot control chamber can be understood as a hydraulic space that is preferably directly connected to the main piston and impacts the main piston with a hydraulic force acting in the closing direction of the main valve. The pilot control chamber is preferably located on the main piston so as to face the traction main control chamber and the compression main control chamber. For example, the main piston is designed so that the end surface of the main piston facing the compression main control chamber or the traction main control chamber and impacted by the hydraulic pressure of the compression main control chamber or the traction main control chamber is larger than the end surface of the main piston facing the pilot control chamber and impacted by the hydraulic pressure of the pilot control chamber.

[0018] During operation of the damping valve arrangement and during movement of the piston rod in the compression direction, hydraulic fluid preferably flows from the distal working chamber of the piston rod, through the second fluid channel, into the optional comfort valve, and into the compression main control chamber. This compresses the pressure in the main control chamber, thereby impacting the main piston with an opening force and causing it to move axially upward. During this process, the main piston lifts from the main valve seat, and hydraulic fluid flows through the main flow duct to the traction main control chamber, particularly the second fluid channel, and then into the proximal working chamber of the piston rod. Simultaneously, and particularly when hydraulically connected in parallel therewith, a portion of the hydraulic fluid flows through the pressure flow channel in the main piston to the pilot control chamber, impacting the main position with a closing force in the direction of the main valve seat. This closing force determines the opening width of the main valve, particularly the cross-section of the main flow duct, which in turn determines the damping force of the damping valve arrangement. The pressure in the pilot control chamber is preferably set by a pilot valve, with hydraulic fluid flowing from the pilot control chamber through a connecting duct into the pilot working chamber and released by a sliding tappet. The opening width of the connecting duct, in particular the outflow cross section, preferably depends on the axial position of the sliding tappet, which is set by means of a solenoid. In the closed position of the pilot valve, the sliding tappet preferably completely closes the connecting duct, causing the hydraulic pressure in the pilot control chamber to build up to a maximum value, closing the main valve and pressing the main piston onto the main valve seat. In the open position of the pilot valve, the connecting duct is at least partially released by the sliding tappet.

[0019] According to a first embodiment, a flow throttle is provided in each of the first flow channel and the second flow channel. The first flow channel preferably extends at least partially or completely through the main piston and preferably fluidically connects the compression main control chamber to the pilot control chamber. Specifically, the first flow channel extends centrally in the axial direction through the main piston. The second flow channel is, for example, arranged in a fixed housing part of the damping valve device and fluidically connects the traction main control chamber to the pilot control chamber. For example, the main piston has a first piston area, which is adjacent to a second piston area with a smaller diameter than the first piston area in the axial direction. The first flow channel preferably extends completely through the first piston area of the main piston, in particular centrally in the axial direction through the main piston and extends into the pilot control chamber. The flow throttle in each flow channel allows the flow throttle to be set separately in the traction phase and the compression phase.

[0020] According to a further embodiment, a check valve is provided in each of the first and second flow channels, allowing hydraulic fluid to flow through each of the first and second flow channels in only one direction. The first flow channel preferably includes a check valve configured to allow hydraulic fluid to flow from the traction main control chamber into the pilot control chamber while preventing hydraulic fluid from flowing in the opposite direction. The second flow channel preferably includes a check valve configured to allow hydraulic fluid to flow from the compression main control chamber into the pilot control chamber while preventing hydraulic fluid from flowing in the opposite direction. The check valve in each flow channel can rectify the hydraulic fluid flow during the traction phase and the compression phase into the pilot control chamber, allowing the same pilot control chamber and adjacent pilot valves to be used during the traction phase and the compression phase.

[0021] According to a further embodiment, the first flow channel and the second flow channel are arranged completely separately from each other, so that separate flows can be guided during the traction phase and the compression phase.

[0022] According to another embodiment, a connecting duct for fluidically connecting the pilot control chamber to the pilot working chamber is formed in the primary piston. The connecting duct extends centrally through the primary piston in the axial direction, from the pilot control chamber into the pilot working chamber. The connecting duct preferably forms a fluid inlet into the pilot valve. The pilot working chamber is preferably directly fluidically adjacent to the connecting duct. The connecting duct in the primary piston preferably ensures a simple, direct fluid connection between the pilot control 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 another embodiment, in the closed position of the pilot valve, the sliding tappet rests against the main piston so that the sliding tappet fluidically closes the connecting duct. The main piston preferably forms a pilot valve seat, against which the sliding tappet rests in the closed position of the pilot valve. The abutment of the sliding tappet against the main piston enables sequential control, wherein the sliding tappet directly impacts the main piston with a closing force applied to the sliding tappet via the armature rod. As a result, a higher operational reliability is achieved. The pilot valve preferably comprises a sliding tappet, which is arranged to be able to move axially 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 movements of the armature and the sliding tappet are mechanically coupled together.

[0024] According to another embodiment, the pilot valve includes a pilot spring, which is arranged such that it impacts the sliding tappet with an axial force acting in the direction of the armature, in particular in the opening direction of the pilot valve. The pilot spring preferably provides a failsafe function in the event of an accidental de-energization of the coil. The guide spring preferably abuts against the sliding tappet and the main piston. Specifically, the pilot spring is designed as a helical spring and abuts against the main piston within its hollow cylindrical region. For example, the pilot spring rests on an annular step on the sliding tappet that points toward the distal working chamber of the piston rod.

[0025] According to another embodiment, the damping valve assembly includes a spring element attached to the main piston such that the spring element impacts the main piston with a spring force acting 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. Specifically, the spring element is arranged so that it impacts the main piston with a spring force acting in the direction of the valve seat. For example, the spring element is designed as a coil spring, which abuts the inner surface of the hollow cylindrical area of the main piston and is supported on the end face of the main piston facing the drive area. The spring element preferably abuts, via one end, a stationary housing portion of the damping valve assembly.

[0026] According to another embodiment, the main piston has a closing surface connected to the pilot control chamber and is arranged so that the hydraulic pressure prevailing in the pilot control chamber impacts the closing surface of the main piston with an axial force acting in the closing direction of the main valve, and the closing surface is formed as a step in the main piston. The main piston is preferably of stepped design, in particular having a first piston area, which points in the direction of the distal working area of the piston rod and abuts against the fixed housing part of the damping valve device in a preferably fluid-tight manner via its outer diameter. The first piston area is preferably designed to be essentially cylindrical. The first piston area is specifically adjacent to a second cylindrical piston area, which is arranged coaxially with the first piston area and preferably has a smaller diameter than the first piston area. An annular end surface, preferably a disc-shaped end surface, pointing in the direction of the drive area is preferably formed on the first piston area. The end face is preferably designed as the closing face of the main piston, specifically the first closing face, and is specifically connected to the pilot control chamber, so that the hydraulic pressure prevailing in the pilot control chamber impacts the main piston, specifically the closing face of the main piston, with an axial force acting in the closing direction of the main valve.

[0027] In addition to the aforementioned closing surface, an annular end surface, oriented toward the drive region, is preferably formed on the second piston region. This annular end surface specifically forms the second closing surface of the main piston. The second closing surface is connected to the pilot working chamber, so that the hydraulic pressure prevailing in the pilot working chamber impacts the second closing surface of the main piston with an axial force acting in the closing direction of the main valve. Therefore, the entire closing surface of the main piston preferably includes the first and second closing surfaces. Specifically, the size and / or position of the main piston's closing surface are identical for both tensile and compressive loads on the vibration damper. The sliding tappet is preferably arranged and designed so that hydraulic fluid can flow through the connecting conduit in only one flow direction.

[0028] According to another embodiment, the main piston has a traction opening surface A which is directly connected to the traction main control chamber. Z , and has a compression opening surface A directly connected to the compression main control chamber D , and wherein the pulling opening surface A Z With compression opening surface A D The ratio A Z / A D It is 1:1 to 5:1, specifically 2:1 to 4:1, and preferably 3:1.

[0029] According to another embodiment, the damping valve arrangement comprises a first pilot outflow line for fluidically connecting the pilot working chamber to the traction main control chamber, and a second pilot outflow line for fluidically connecting the pilot working chamber to the compression main control chamber. Thus, hydraulic fluid can flow out of the pilot working chamber during both the traction phase and the compression phase.

[0030] The first pilot outflow line is preferably formed in a stationary housing portion of the vibration damper and preferably extends from the pilot working chamber into the traction main control chamber. The first pilot outflow line preferably includes a check valve configured to allow hydraulic flow from the pilot working chamber into the first fluid channel, particularly the piston rod proximal working chamber, while preventing hydraulic flow in the opposite direction. For example, the first pilot outflow line is preferably positioned above the sliding tappet relative to its traction direction.

[0031] The second pilot outflow conduit is preferably designed to fluidically connect the pilot working chamber to the piston rod distal working chamber. The second pilot outflow conduit is specifically formed in the primary piston and preferably extends axially through the primary piston, specifically through the first and second piston regions. The second pilot outflow conduit preferably extends from the pilot working chamber to the compression main control chamber. The second pilot outflow conduit preferably includes a check valve, which is configured to allow hydraulic flow from the pilot working chamber to the piston rod distal working chamber and prevent hydraulic flow in the opposite direction.

[0032] According to another embodiment, the damping valve arrangement includes a comfort valve through which the hydraulic fluid can flow during both the compression and traction phases. Specifically, the comfort valve includes at least one comfort spring disc pack, for example comprising at least one or more spring discs that abut against a comfort valve seat. The comfort valve preferably has two spring disc packs, one designed to damp the hydraulic fluid during movement of the piston rod in the traction direction, and the other designed to damp the hydraulic fluid during movement of the piston rod in the compression direction. The comfort valve is preferably directly fluidically connected to the distal working chamber of the piston rod. The comfort valve preferably forms the end of the working piston that points toward the base valve.

[0033] According to another embodiment, the damping valve arrangement includes a bypass line arranged such that the bypass line fluidically connects the compression main control chamber and the traction main control chamber to one another. The bypass line is preferably formed hydraulically in parallel with the main flow line, serving as a bypass for the main valve. Specifically, the bypass line extends from the compression main control chamber to the traction main control chamber, fluidically connecting the compression main control chamber and the traction main control chamber to one another.

[0034] According to another embodiment, a check valve is provided in the bypass line, allowing hydraulic fluid to flow through the bypass line only in one direction. The bypass line preferably includes a check valve that is arranged and designed to allow hydraulic fluid to flow from the compression main control chamber into the traction main control chamber and to prevent hydraulic fluid from flowing in the opposite direction. Specifically, a throttle element is provided that is hydraulically connected in series with the check valve in the bypass line. For example, the damping valve arrangement further includes a further bypass line that is preferably hydraulically connected in parallel with the bypass line and that includes a flow throttle valve. The hydraulic fluid can preferably flow through the further bypass line during both the traction and compression phases of the vibration damper.

[0035] According to another embodiment, the sliding tappet has an opening surface that, in the closed position of the pilot valve, at least partially abuts the main piston and has a gap. The opening surface is preferably formed on the end face of the sliding tappet that faces the connecting line and is preferably arranged such that it completely closes the connecting line in the closed position of the pilot valve. The opening surface preferably has a (particularly central) gap that points in the axial direction and, for example, is conical. For example, the gap is designed to be cylindrical with a circular, annular, or angular cross-section. The gap preferably serves to increase the opening surface and thereby set the opening pressure of the pilot valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be explained in more detail below with the aid of a number of exemplary embodiments with reference to the accompanying drawings, in which:

[0037] Figure 1schematically illustrates a longitudinal cross-sectional view of a vibration damper according to an exemplary embodiment;

[0038] Figure 2 schematically illustrates a longitudinal cross-sectional view of a damping valve device of a vibration damper in a compression phase according to an exemplary embodiment;

[0039] Figure 3 schematically shows a longitudinal sectional view of a damping valve device of a vibration damper according to an exemplary embodiment in a traction phase;

[0040] Figure 4 Schematically illustrates a hydraulic circuit diagram of a damping valve device according to an exemplary embodiment;

[0041] Figure 5 Schematically illustrates a hydraulic circuit diagram of a damping valve device according to an exemplary embodiment;

[0042] Figure 6 A hydraulic circuit diagram of a damping valve device according to an exemplary embodiment is schematically shown. DETAILED DESCRIPTION

[0043] Figure 1 A vibration damper 10 is shown, wherein the vibration damper 10 is a multi-tube vibration damper, such as a twin-tube vibration damper. The vibration damper 10 has an outer tube 12, which forms the outer surface of the vibration damper 10, in particular the housing. An inner tube 14, also referred to as a damper tube, is disposed coaxially within the outer tube 12. A compensating chamber 16 is formed between the outer tube 12 and the inner tube 14. Preferably, the compensating chamber 16 is at least partially filled with a hydraulic fluid. For example, the compensating chamber 16 can be partially filled with gas.

[0044] A working piston 18 is connected to a piston rod 20 and is disposed in an inner tube 14 such that it can move 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 arrangement 54. The working piston 18 divides the interior of the inner tube 14 into a first working chamber 22 and a second working chamber 24, the first working chamber being disposed proximate to the piston rod and the second working chamber being disposed distally therefrom.

[0045] The interior of the outer tube 12 is fluid-tight on the piston rod side by means of a closure pack 34. Opposite the closure pack 34, at the distal end of the piston rod, the interior of the outer tube 12 is fluid-tight by means of a base component 36. For example, a base valve 38 is provided on the base component 36, which is specifically attached to the distal end of the piston rod of the inner tube 14. For example, the base valve 38 is a check valve through which fluid can flow 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 proximal piston rod ends of the inner tube 14 and the outer tube 12 are preferably fastened to the closure pack 34.

[0046] For example, the piston rod 20 has an optional traction stop, which is impacted with a spring force by the spring element 42 during the movement in the traction direction Z.

[0047] Figure 2 An exemplary damping valve arrangement 54 is shown, which is preferably arranged in the working piston 18 of the vibration damper 10. The damping valve arrangement 54 is designed, for example, as a pilot-controlled pressure control valve and comprises a preferably cylindrical damping valve housing, for example, having a substantially tubular tube section 45 and an upper housing part 44, which is designed, for example, integrally with the tube section 45. The piston rod 20 is preferably attached to the upper housing part 44. For example, the upper housing part 44 has a connection region (not shown) with one or more connection contacts for supplying power to the damping valve arrangement 54. The connection contacts for the power supply are preferably connected to a drive unit.

[0048] For example, the damping valve device 54 includes a drive region 48 and a valve region 50. For example, the drive region 48 is located in the upper region of the damping valve device 54, facing the piston rod 20. The drive region is preferably located approximately above the valve region 50, particularly in the pulling direction Z. The drive region 48 preferably includes a drive element in the form of a solenoid. The solenoid includes a coil 52 having multiple windings made of an electrical conductor. The coil 52 is preferably located concentrically within the tube portion 45. For example, the coil 52 abuts against the inner wall of the tube portion 45. For example, a cover section 56 is axially disposed between the coil 52 and the upper housing portion 44. The coil 52 preferably abuts against the cover section 56, particularly, it is fastened to the cover section. The cover section 56 is, for example, made of metal, particularly a magnetic material, preferably a low magnetic resistance material. For example, the coil 52 includes a coil carrier around which the coil windings are wound. The coil 52 at least partially or completely surrounds the armature space 60, which extends centrally in the axial direction. The armature 62 is mounted so as to be axially movable within the armature space 60. The armature 62 is preferably cylindrical and has a diameter slightly smaller than the diameter of the armature space 60, so 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, for example having a circular cross-section, which extends centrally in the axial direction through the armature space 60. The armature space 60 is preferably bounded by an at least partially hollow cylindrical pole tube 64. The pole tube 64 preferably has a base and is designed to be open, particularly in the direction of the valve region 50. The pole tube 64 is preferably made of a magnetizable or magnetic material and has, for example, a magnetic separation 58.

[0049] The coil 52 is preferably designed and arranged so that when subjected to an electric current, a magnetic field is formed, the magnetic field lines of which preferably extend substantially in the axial direction in the armature space 60. The armature 62 is preferably made of a magnetizable or magnetic material and is movable in the axial direction, corresponding to the magnetic field formed by the coil 52.

[0050] The hollow cylindrical region of the pole tube 64 is axially adjacent and coaxial to the pole tube element, together forming the pole tube 64, wherein the pole tube 64 can be formed in multiple parts, integrally, or in a single part. The pole tube 64 has an upper tubular region with a particularly constant inner diameter, preferably in the form of a hollow cylinder, and extending, for example, from the cover portion 56 in the axial direction as far as beyond the armature 62. The upper hollow cylindrical region is axially adjacent to a lower region of increased diameter, wherein the outer surface of the pole tube 64 preferably extends as far as the tube portion 45 and at least partially abuts against it, sealing it in a fluid-tight manner relative to the tube portion 45, for example, by means of a sealing element. The tube portion 45 at least partially or completely surrounds the valve region 50 in the axial and circumferential directions, which will be explained in more detail in the following paragraphs.

[0051] For example, valve area 50 includes a main valve 68 and a pilot valve 70. Preferably, the damping valve arrangement 54 disposed in the working piston 18 includes exactly one main valve 68 and / or exactly one pilot valve 70. Preferably, hydraulic fluid can flow through the main valve 68 and / or the pilot valve 70 during movement of the piston rod 20 in both the traction direction Z and the compression direction D. A seal 26, such as a sealing ring, is preferably attached to the working piston 18 and seals the working piston 18 against the damper tube 14 in a fluid-tight manner. The seal 26 preferably abuts against the outer surface of the working piston 18 and the inner surface of the damper tube 14 in a fluid-tight manner. Furthermore, the damping valve arrangement 54 optionally includes a comfort valve 28. The comfort valve 28 is preferably designed to allow hydraulic fluid to flow through it in both the compression direction D and the traction direction Z. Specifically, the comfort valve includes at least one comfort spring disk package, for example, comprising at least one or more spring disks abutting a comfort valve seat. The comfort valve 28 preferably has two spring disc packs, one of which is designed to damp the hydraulic fluid during movement of the piston rod 20 in the traction direction Z, and the other of which is designed to damp the hydraulic fluid during movement of the piston rod 20 in the compression direction D. The comfort valve 28 is preferably directly fluidically connected to the piston rod distal working chamber 24. Preferably, the comfort valve 28 is disposed in the piston rod distal working chamber 24 and, in particular, forms the end of the working piston 18 that points toward the base valve 36. For example, the comfort valve 28 includes a comfort valve housing 32, which is preferably formed separately from and fixedly connected to the tube portion 45, or integrally formed with the tube portion 45. For example, the outer diameter of the comfort valve housing 32 is larger than that of the tube portion 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 surrounds the comfort spring disc pack 30 axially and circumferentially.

[0052] The working piston 18 includes a first fluid channel 39 leading to the first working chamber 22, wherein the first fluid channel 39 is formed, for example, in the tube portion 45, for example, as a circular opening. The damping valve arrangement 54 is preferably fluidically connected to the first piston rod proximal working chamber 22 via the first fluid channel 39. For example, when the piston rod 20 moves in the traction direction Z, the first fluid channel 39 forms a fluid inlet for admitting hydraulic fluid into the damping valve arrangement 54. When the piston rod moves in the compression direction D, the first fluid channel 39 forms a fluid outlet for discharging hydraulic fluid from the damping valve arrangement 54.

[0053] The working piston 18, in particular the comfort valve 28, preferably has a second fluid passage 40 leading to the second working chamber 24. The damping valve device 54 is preferably fluidically connected to the second piston rod distal working chamber 24 via this second fluid passage. For example, when the piston rod 20 moves in the compression direction D, the second fluid passage 40 forms a fluid inlet for allowing hydraulic fluid to enter the comfort valve 28 and the main valve 68; when the piston rod moves in the traction direction Z, the second fluid passage 40 forms a fluid outlet for discharging hydraulic fluid from the comfort valve 28 and the main valve 68.

[0054] During operation of the damping valve arrangement 54, when the piston rod moves in the traction direction Z, hydraulic fluid preferably flows from the first fluid passage 39 into the main valve 68 and the pilot valve 70, then optionally through the comfort valve 28 and into the second fluid passage 40. The main valve 68 includes a primary piston 76, which is arranged to move axially within a primary working chamber 78. For example, the main valve 68 also includes a housing portion 80, which at least partially defines the primary working chamber 78 and provides an axial guide for the primary piston 76. For example, the housing portion 80 is disposed coaxially within the tubular portion 45. A gap, particularly an annular space, is preferably formed between the housing portion 80 and the tubular portion 45. The primary piston 76 is preferably disposed concentrically within the housing portion 80. The primary piston 76 preferably divides the primary working chamber 78 into a compression main control chamber 82a, a traction main control chamber 82b, and a pilot control chamber 84. The master piston 76 specifically has a first flow channel 86a that extends through the master piston 76 and forms a fluid connection between the compression main control chamber 82a and the pilot control chamber 84. For example, the first flow channel 86a extends centrally in the axial direction through the master piston 76. The housing portion 80 has a second flow channel 86b that forms a fluid connection between the traction main control chamber 82b and the pilot control chamber 84. For example, the second flow channel 86b is arranged at the same height as the first flow channel 39. The first and second flow channels 86a, 86b preferably each have a respective flow throttle 96a, 96b, in particular a cross-sectional constriction.

[0055] For example, the compression main control chamber 82a is formed between the comfort valve 28 and the main piston 76. The traction main control chamber 82b is preferably formed as the above-mentioned gap, in particular the annular space, between the housing portion 80 and the tube portion 45. The hydraulic pressure of the second piston rod distal working chamber 24 is preferably dominant in the compression main control chamber 82a, wherein the hydraulic pressure of the first piston rod proximal working chamber 22 is preferably dominant in the traction main control chamber 82b.

[0056] A guide element 72 is preferably positioned in a fixed manner in the damping valve arrangement 54 between the main valve 68 and the comfort valve 28. For example, the guide element 72 is tubular and serves to guide the hydraulic fluid from the comfort valve 28 to the main valve 68. For example, the guide element 72 at least partially forms the compression main control chamber 82a. The guide element 72 is preferably connected directly or indirectly to the pipe section 45 and positioned in a fixed manner relative to the pipe section. A main valve seat 90 is preferably formed on the guide element 72. For example, a spring assembly 77 is connected to the main piston 76, and when the main valve 68 is in the closed position, the spring assembly 77 abuts the main valve seat 90 of the guide element 72. The spring assembly 77 preferably includes a plurality of, in particular two, spring discs, which are coaxially arranged relative to one another and preferably abut one another. The spring disc of the spring assembly 77 that faces toward the compression main control chamber 82a preferably abuts the main valve seat 90 and, in particular, has a bypass opening 74.

[0057] In the open position of the main valve 68 (in which the main piston 76 moves 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 duct 92 is formed between the main piston 76 and the main valve seat 90. The main flow duct 92 forms a fluid connection between the first working chamber 22 and the second working chamber 24. Specifically, the main flow duct 92 forms a fluid connection between the compression main control chamber 82a and the traction main control chamber 82b. Optionally, the damping valve device 54 has a bypass duct 88, which is preferably formed hydraulically in parallel with the main flow duct 92 and serves as a bypass for the main valve 68. For example, the bypass duct 88 extends from the compression main control chamber 82a to the traction main control chamber 82b and fluidically connects the compression main control chamber and the traction main control chamber to each other. The bypass conduit 88 preferably has a check valve that is arranged and designed such that it allows hydraulic flow from the pressure main control chamber 82a to flow into the traction main control chamber 82b and blocks hydraulic flow in the opposite direction.

[0058] The main piston 76 is preferably of stepped design, for example, having a first piston region 113 which points in the direction of the distal working region 24 of the piston rod and rests against the housing part 80 in a fluid-tight manner due to its outer diameter. For example, the first piston region 113 is essentially cylindrical. The first piston region 113 is adjacent to a second cylindrical piston region 114 which is arranged coaxially with the first piston region 113 and has a smaller diameter than the first piston region 113. An annular end face 46 pointing in the direction of the drive region 48 is preferably formed on the main piston 76, in particular on the first piston region 113. The end face 46 serves as a closing surface A of the main piston 76. S The pilot control chamber 84 is adjacent to the pilot control chamber 84, so that the hydraulic pressure prevailing in the pilot control chamber 84 impacts the main piston 76, in particular the closing surface 46 of the main piston 76, with an axial force acting in the closing direction of the main valve. The pilot control chamber 84 is preferably bounded by the closing surface 46, the housing portion 80, and the main piston 76 (in particular, the second region of the main piston 76). A first flow channel 86a, which connects the compression main control chamber 82a, preferably extends only through the first region of the main piston 76, in particular centrally through the main piston in the axial direction into the pilot control chamber 84. The first flow channel 86a preferably includes a check valve, which is configured to allow hydraulic flow from the compression main control chamber 82a to enter the pilot control chamber 84 and prevent hydraulic flow in the opposite direction. Similarly, the second flow channel 86b preferably includes a check valve, which is configured to allow hydraulic flow from the traction main control chamber 82b to enter the pilot control chamber 84 and prevent hydraulic flow in the opposite direction.

[0059] An annular end surface A pointing toward the drive region 48 is preferably formed on the main piston 76 , in particular on the second piston region 114 . SP Except for the closed surface A S In addition, end face A SP Also serves as another, specifically second closing surface A of the main piston 76 SP and is connected to the pilot working chamber 100, so that the hydraulic pressure prevailing in the pilot working chamber 100 impacts the main piston 76, especially the closing surface A of the main piston 76, with an axial force acting in the closing direction of the main valve 68. SP .

[0060] A spring element 94 is attached to the side of the main piston 76 facing away from the main valve seat 90. The spring element 94 is arranged so that it strikes the main piston 76 with a spring force acting in the direction of the valve seat 90. For example, the spring element 94 is a helical spring which bears against the inner surface of the hollow cylindrical region of the housing part 80 and is supported by one end against the end face 46 of the main piston 76, in particular the closing face A. SOn the other hand, the end face points in the direction of the drive region 48. The spring element 94 is preferably supported by the other end on the housing part 80. For example, the housing part has a groove in which the spring element 94 is arranged.

[0061] A connecting duct 98 is preferably formed in the primary piston, which extends, in particular, from the pilot control chamber 84 centrally in the axial direction through the primary piston 76 into the pilot working chamber 100. The connecting duct 98 preferably forms a fluid inlet into the pilot valve 70. For example, the region of the primary piston 76 pointing in the direction of the drive region 48 is designed as a hollow cylinder, wherein the interior of the hollow cylindrical region preferably at least partially forms the pilot working chamber 100. The pilot working chamber 100 is preferably directly fluidically adjacent to the connecting duct 98.

[0062] For example, the pilot valve 70 includes a sliding tappet 102 that is axially movable within the pilot working chamber 100. The sliding tappet 102 preferably abuts the armature 62, particularly the armature rod 65, at its end distal from the main valve 68, such that the movements of the armature 62 and the sliding tappet 102 are coupled, at least during movement of the armature 62 in the direction of the sliding tappet 102. In the closed position of the pilot valve 70, the sliding tappet 102 preferably abuts the main piston 76, completely closing the connecting conduit 98. In the open position of the pilot valve 70, the sliding tappet 102 is lifted from the main piston 76, opening the connecting conduit 98 and establishing fluid flow between the pilot control chamber 84 of the main valve 68 and the pilot working chamber 100. The sliding tappet 102 is preferably attached so as to be axially movable relative to the main piston 76. In particular, the sliding tappet 102 is axially guided by the primary piston 76 and preferably bears against the inner wall of the hollow cylindrical region of the primary piston 76 in a fluid-tight manner.

[0063] For example, the sliding tappet 102 has a T-shaped longitudinal cross-section, wherein the sliding tappet 102 has a first region that faces the connecting pipe 98 and has a larger cross-section than the cross-section of the connecting pipe 98, and a second region that faces the armature 62 and has a larger cross-section than the cross-section of the first region. The second region preferably extends over the entire cross-section of the pilot working chamber 100.

[0064] In the closed position, the sliding tappet 102 preferably abuts against a first valve seat formed in the primary piston 76. The sliding tappet 102 of the pilot valve 70 preferably has at least one passage hole or a plurality of passage holes 112, which extend through the sliding tappet 102 in the axial direction and form a flow duct for the hydraulic fluid through the sliding tappet 102. The flow channel 112, in particular the pilot working chamber 100, is preferably fluidically connected to the first fluid channel 39 and the second fluid channel 40.

[0065] The pilot valve 70 preferably includes a pilot spring 108, which is arranged so that it impacts the sliding tappet 102 with an axial force acting in the direction of the armature 62, particularly in the opening direction of the pilot valve 70. The pilot spring 108 preferably serves as a fail-safe in the event of coil de-energization and is designed to allow hydraulic fluid to escape through the pilot outflow line 104a, particularly the fail-safe valve therein. The pilot spring preferably bears against the sliding tappet 102 and the primary piston 76. Specifically, the pilot spring 108 is designed as a coil spring and bears against the primary piston 76 within its hollow cylindrical region. For example, the pilot spring 108 rests on an annular step of the sliding tappet 102 that points toward the distal piston rod working chamber 24.

[0066] The sliding tappet 102 preferably has an opening surface 110 formed on a first area thereof facing the connecting duct 98 and configured to close the connecting duct 98 in the closed position of the pilot valve 70. For example, the opening surface 110, also referred to as the pilot opening surface AP, preferably has a central gap, oriented in the axial direction and, for example, conical in shape. For example, the gap can be cylindrical with a circular, annular, or angular cross-section. The gap preferably serves to enlarge the opening surface and thereby set the opening pressure of the pilot valve 70.

[0067] The pilot valve 70 preferably includes a first pilot outflow conduit 104a designed and arranged to fluidly connect the pilot working chamber 100 to the first fluid channel 39, preferably to the piston rod proximal working chamber 22. For example, the first pilot outflow conduit 104a is formed in the housing portion 80, particularly in a housing element 106 fixedly connected thereto, and preferably extends from the pilot working chamber 100 to the traction main control chamber 82b. The first pilot outflow conduit 104a preferably includes a check valve configured to enable hydraulic flow from the pilot working chamber 100 to flow into the first fluid channel 39 and to prevent hydraulic flow in the opposite direction.

[0068] The pilot valve 70 preferably includes a second pilot outflow conduit 104b designed and arranged to fluidly connect the pilot working chamber 100 to the second fluid passage 40, preferably to the piston rod distal working chamber 24. For example, the second pilot outflow conduit 104b is formed in the master piston 76 and preferably extends axially through the master piston, specifically through the first and second piston regions. The second pilot outflow conduit 104b preferably extends from the pilot working chamber 100 to the compression main control chamber 82a. The second pilot outflow conduit 104b preferably includes a check valve configured to allow hydraulic flow from the pilot working chamber 100 to flow into the second fluid passage 40 while preventing hydraulic flow in the opposite direction.

[0069] During operation of the damping valve arrangement 54, when the piston rod 20 moves in the compression direction D, hydraulic fluid flows through the second fluid passage 40 into the optional comfort valve 28 and into the compression main control chamber 82a. The pressure in the compression main control chamber 82a thereby impacts the main piston 76 with an opening force, causing it to move axially upward. During this process, the main piston 76 lifts from the main valve seat 90, and hydraulic fluid flows through the main flow channel 92 into the traction main control chamber 82b, specifically the second fluid passage 39. Simultaneously, a sub-flow of hydraulic fluid flows through the first flow channel 86a in the main piston 76 into the pilot control chamber 84, impacting the main piston 76 with a closing force acting in the direction of the main valve seat 90. This closing force determines the opening width of the main valve 68, specifically the cross-section of the main flow channel 92, which in turn determines the damping force of the damping valve arrangement 54. The pressure in the pilot control chamber 84 is set by the pilot valve 70, where hydraulic fluid flows from the pilot control chamber 84 through the connecting line 98 into the pilot working chamber 100, where it is released via a sliding tappet 102. The opening width of the connecting line 98 depends on the axial position of the sliding tappet 102, which is set, in particular, pre-set, by means of the solenoid 54. In the closed position of the pilot valve 70, the sliding tappet 102 preferably completely closes the connecting line 98, causing the hydraulic pressure in the pilot control chamber 84 to increase to a maximum value. The main valve 68 closes and, preferably, is impacted by a force acting in the closing direction, thereby pressing the main piston 76 against the main valve seat 90. In the open position of the pilot valve 70, the sliding tappet 102 at least partially releases the connecting line 98, allowing hydraulic fluid to flow through a passage hole 112 in the sliding tappet 102 and, via a first pilot outflow line 104a disposed downstream of the passage hole 112, into the traction main control chamber 82b, in particular, the second fluid passage 39. Another sub-flow may optionally flow through a bypass conduit 88 which fluidly connects the compression main control chamber 82a to the traction main control chamber 82b. Figure 2The arrows in illustrative diagram schematically illustrate fluid flows during movement of the piston rod 20 in the compression direction D, wherein the solid line represents the main flow through the main valve 68 , and the dotted line represents the pilot flow through the pilot valve 70 and the bypass flow through the bypass conduit 88 .

[0070] Figure 3 Shown Figure 2 The damping valve device 54 is shown, wherein the fluid flow during the movement of the piston rod in the traction direction is shown. The main piston 76 preferably has a traction opening surface A Z and compression opening surface A D . Compression opening surface A D It is the surface directly connected between the main piston 76 and the compression main control chamber 82a, wherein the traction opening surface A Z It is the surface where the main piston 76 is directly connected to the traction main control chamber 82b. For example, the traction opening surface A Z and compression opening surface A D The ratio between Z / A D ) is 1:1 to 5:1, in particular 2:1 to 4:1, preferably 3:1.

[0071] Figure 4 The hydraulic circuit diagram of the damping valve arrangement 54 is shown, wherein the solid line represents the main volume flow and the dashed line represents the pilot flow. The working chambers 22, 24 of the vibration damper 54 are fluidically connected to each other by the main volume flow flowing through the main valve 68 of the damping valve arrangement 54. The pilot valve 70 is preferably connected hydraulically in parallel with the main valve 68. Specifically, the pilot valve 70 is designed so that it acts on the closing surface A of the main piston 76. S The hydraulic pressure on the pilot valve 70 is specifically set as a function of the position of the sliding tappet 102 of the pilot valve 70. The piston rod distal working chamber 24 is preferably fluidly connected to the pilot valve 70 via the first flow channel 86a, for example, via a throttle valve 96a and a check valve. The piston rod proximal working chamber 22 is preferably fluidly connected to the pilot valve 70 via the second flow channel 86b, for example, via a throttle valve 96b and a check valve.

[0072] Figure 5 Another example of a hydraulic circuit diagram of the damping valve device 54 is shown. Figure 4 The bypass conduit 88 is substantially the same, with the bypass conduit 88 additionally being provided between the piston rod distal working chamber 24 and the piston rod proximal working chamber 22. For example, a throttle element and a check valve are provided in the bypass conduit 88 so as to be hydraulically connected in series with each other, so that the hydraulic fluid can flow through the bypass conduit 88 in only one direction, specifically from the piston rod distal working chamber 24 into the piston rod proximal working chamber 22. The bypass conduit 88 is preferably provided hydraulically in parallel with the pilot valve 70 and / or the main valve 68.

[0073] Figure 6 Another example of a hydraulic circuit diagram of the damping valve device 54 is shown. Figure 4 or Figure 5 Essentially corresponding, the damping valve arrangement 54 additionally has a further bypass line 116 which is preferably connected hydraulically in parallel with the bypass line 88 and, in particular, has a flow throttle. During the traction and compression phases of the vibration damper 10 , the hydraulic fluid flow can preferably be passed through the further bypass line 116 .

[0074] Reference Signs List

[0075] 10 Vibration damper

[0076] 12 outer tube

[0077] 14 inner tube

[0078] 16 Compensation chamber

[0079] 18 Working piston

[0080] 20 piston rod

[0081] 22 First / piston rod proximal working chamber

[0082] 24 Second / piston rod distal working chamber

[0083] 26 seals

[0084] 28 Comfort Valve

[0085] 30 Comfort Springform Pan Buns

[0086] 32 Comfort valve housing

[0087] 34 closed packages

[0088] 36 base parts

[0089] 38 base valve

[0090] 39 first fluid channel leading to the first working chamber 22

[0091] 40 leads to the second fluid channel of the second working chamber 24

[0092] 42 Spring element

[0093] 44 Upper part of the shell

[0094] 45 tube section

[0095] 46 end face / closed face

[0096] 48 drive area

[0097] 50 valve area

[0098] 52 Coil

[0099] 54 Damping valve device

[0100] 56 Covering part

[0101] 58 Magnetic separation

[0102] 60 Armature space

[0103] 62 Armature

[0104] 64 diodes

[0105] 65 armature rod

[0106] 68 Main valve

[0107] 70 pilot valve

[0108] 72 guide elements

[0109] 74 bypass opening

[0110] 76 Main piston

[0111] 77 Spring Assembly

[0112] 78 Main working chamber

[0113] 80 shell part

[0114] 82a,b Traction / compression main control chamber

[0115] 84 pilot control chamber

[0116] 86a,b flow channel

[0117] 88 Bypass pipe

[0118] 90 Main valve seat

[0119] 92 Main flow pipe

[0120] 94 spring elements

[0121] 96a,b flow throttle valve

[0122] 98 connecting pipes

[0123] 100 pilot working chamber

[0124] 102 sliding tappet

[0125] 104a First pilot outflow pipe

[0126] 104b Second pilot outflow pipe

[0127] 106 housing components

[0128] 108 pilot spring

[0129] 110 Opening surface of sliding tappet

[0130] 112 channel holes

[0131] 113 First Piston Area

[0132] 114 Second Piston Area

[0133] 116 Another bypass pipe

[0134] A S The first closing surface of the main piston 76

[0135] A D Compression opening surface of main piston 76

[0136] A Z The traction opening surface of the main piston 76

[0137] A SP Second closing surface of the primary piston 76 .

Claims

1. A vibration damper (10) for a motor vehicle, comprising: an outer tube (12) and an inner tube (14), the inner tube being arranged coaxially with the outer tube, and a working piston (18) configured to be movable in the axial direction within the inner tube (14) and to divide the interior of the inner tube (14) into a piston rod proximal working chamber (22) and a piston rod distal working chamber (24), A damping valve device (54) is arranged in the working piston (18), wherein the damping valve device (54) has: Coil (52), an armature (62) capable of moving in an axial direction, the armature being at least partially disposed within the coil (52), a main valve (68) having a main piston (76) which separates a compression main control chamber (82a), a traction main control chamber (82b) and a pilot control chamber (84) from one another, A pilot valve (70) designed to allow a hydraulic fluid flow to pass through the pilot valve in both a traction phase and a compression phase, the pilot valve comprising a pilot working chamber (100) and a sliding tappet (102) disposed in the pilot working chamber (100) and movable in the axial direction by means of the armature (62); and a connecting pipe (98) provided between the pilot control chamber (84) and the pilot working chamber (100) and fluidically connecting the pilot control chamber and the pilot working chamber to each other, It is characterized in that The compression main control chamber (82a) is fluidly connected to the pilot control chamber (84) through the first flow passage (86a), and the traction main control chamber (82b) is fluidly connected to the pilot control chamber (84) through the second flow passage (86b).

2. The vibration damper (10) according to claim 1, wherein a flow throttle valve (96a, 96b) is provided in each of the first flow channel (86a) and the second flow channel (86b).

3. A vibration damper (10) according to any one of the preceding claims, wherein a check valve is respectively provided on the first flow channel (86a) and the second flow channel (86b), so that the hydraulic fluid can respectively flow through the first flow channel (86a) and the second flow channel (86b) in only one direction.

4. The vibration damper (10) according to any one of the preceding claims, wherein the first flow channel (86a) and the second flow channel (86b) are arranged to be separated from each other.

5. The vibration damper (10) according to any one of the preceding claims, wherein the connecting duct (98) for fluidly connecting the pilot control chamber (84) to the pilot working chamber (100) is formed in the main piston (76).

6. The vibration damper (10) according to claim 5, wherein in the closed position of the pilot valve (70), the sliding tappet (102) abuts against the main piston (76) so that it fluidically closes the connecting duct (98).

7. A vibration damper (10) according to any one of the preceding claims, wherein the pilot valve (70) has a pilot spring (108), which is arranged so that it impacts the sliding tappet (102) with an axial force acting in the direction of the armature (62).

8. A vibration damper (10) according to any one of the preceding claims, wherein the damping valve device (54) has a spring element (94), which is attached to the main piston (76) so that the spring element impacts the main piston (76) with a spring force acting in the closing direction of the main valve (68).

9. The vibration damper (10) according to any one of the preceding claims, wherein the main piston (76) has a closing surface (A) connected to the pilot control chamber (84). S ), and is arranged so that the hydraulic pressure prevailing in the pilot control chamber (84) impacts the closing surface (A) of the main piston (76) with an axial force acting in the closing direction of the main valve (68) S ), and wherein the closed surface (A S ) is formed as a step in the main piston (76).

10. The vibration damper (10) according to any one of the preceding claims, wherein the main piston (76) has a traction opening surface (A) directly connected to the traction main control chamber (82b). Z ), and having a compression opening surface (A) directly connected to the compression main control chamber (82a) D ), and wherein the traction opening surface (A Z ) and the compression opening surface (A D ) between the ratio (A Z / A D ) is 1:1 to 5:1, specifically 2:1 to 4:1, preferably 3:

1.

11. A vibration damper (10) according to any one of the preceding claims, wherein the damping valve device (54) has a first pilot outflow conduit (104a) for fluidly connecting the pilot working chamber (100) to the traction main control chamber (82b) and a second pilot outflow conduit (104b) for fluidly connecting the pilot working chamber (100) to the compression main control chamber (82a).

12. A vibration damper (10) according to any one of the preceding claims, wherein the damping valve arrangement (54) comprises a comfort valve (28) through which a hydraulic fluid flow can pass in the compression phase and in the traction phase.

13. A vibration damper (10) according to any one of the preceding claims, wherein the damping valve arrangement (54) comprises a bypass conduit (88) arranged such that the bypass conduit fluidically connects the compression main control chamber (82a) and the traction main control chamber (82b) to each other.

14. The vibration damper (10) of claim 13, wherein a check valve is provided on the bypass conduit (88) such that hydraulic fluid flow is only possible in one direction through the bypass conduit (88).

15. The vibration damper (10) according to any one of the preceding claims, wherein the sliding tappet (102) has an opening surface (A P ), in the closed position of the pilot valve (70), the opening surface at least partially abuts against the main piston (76), and wherein the opening surface (A P ) has a gap.

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