Vibration dampers, in particular adjustable shock absorbers for motor vehicles

Abstract

Vibration damper (1) for motor vehicles, comprising a piston (3) guided within a cylinder tube (2) and axially displaceable therein, which is attached to a piston rod (4), divides the cylinder tube (2) into a first chamber (5) and a second chamber (6) and has connecting channels (13, 14, 15) through which a damping fluid arranged in the chambers (5, 6) flows, which extend from an end face (8) of the piston (3) facing the first chamber (5) to an opposite end face (9) of the piston (3) facing the second chamber (6), wherein The flowable connecting channels (13, 14, 15) are each arranged along circular circumferences with different radii, with openings of the connecting channels (13) being arranged radially furthest inwards on the end face (8) of the piston (3) facing an adjusting part (18), the openings of the connecting or bypass channels (15) being radially furthest outwards, and openings of the connecting channels (14) being arranged radially between the connecting channels (13, 15). and whereby exactly one adjusting element (18) is rotatably mounted on the piston rod (4) parallel to the end faces (8, 9) of the piston (3), which is rotationally symmetrical, and which is spring-loaded in one direction of rotation, and which has through-holes (20, 23) that are arranged distributed along a circumference with different radii, wherein the through-holes (20) associated with the connecting or bypass channels (15) of the piston (3) are arranged radially further outwards than the through-holes (23) associated with the connecting channels (13, 14), and which is associated with at least one connecting or bypass channel (15) and by whose rotation the flow cross-section of each associated connecting or bypass channel (15) is adjusted.bypass channel (15) is changeable, wherein the adjusting part (18) has a contact surface abutting one of the two end faces (8), which is penetrated by at least one through-bore (20) opening on one side towards the end face (8) and on the other side towards the corresponding chamber (5), wherein the end-face opening of the through-bore (20) in a first rotational position of the adjusting part (18) has no overlap with the end-face opening of the connecting or bypass channel (15) of the piston (3) abutting the adjusting part (18) and in a second rotational position of the adjusting part (18) has complete overlap with the end-face opening of the connecting or bypass channel (15) of the piston (3) abutting the adjusting part (18).

Description

[0001] The present invention relates to a vibration damper, in particular a damping-adjustable shock absorber for motor vehicles.

[0002] In general, today's vehicles include wheel suspensions, which comprise an arrangement of springs and shock absorbers designed to prevent or mitigate the transmission of shocks caused by road irregularities from a wheel to a vehicle body. Typical vibration or shock absorbers usually comprise a cylinder tube filled with a fluid, such as oil. An axially displaceable piston is guided within the cylinder tube. The piston is attached to a piston rod that protrudes from the cylinder tube and is connected to a part of the wheel suspension or the vehicle body. The cylinder tube is correspondingly connected to the other vehicle component, i.e., the vehicle body or the wheel suspension.

[0003] The piston divides the cylinder tube into a first chamber and a second chamber. The piston itself has connecting channels through which the fluid contained in the chambers can flow. The connecting channels extend from an end face of the piston facing the first chamber to an opposite end face of the piston facing the second chamber.

[0004] The resistance experienced by the fluid flowing through the connecting channels during axial movement of the piston within the cylinder barrel provides the desired damping force, which opposes the piston movement in the cylinder barrel. Damping-adjustable shock absorbers, i.e. shock absorbers whose damping force can be changed during use in a vehicle, also usually have switchable valve devices on the piston, with which, for example, additional connecting channels in the piston, also referred to herein as bypass channels, can be opened or closed in order to change the overall resistance opposed to the fluid flowing from one chamber to the other during axial movement of the piston in the cylinder barrel. Such known piston-cylinder arrangements orDue to the switchable valve devices provided on the piston, vibration dampers usually require a relatively large axial installation space of the piston and thus of the entire shock absorber.

[0005] DE 32 15 614 A1 relates to a hydraulic single-tube shock absorber with damping control, whereby the damping is controlled by rotational movement of one or more pistons around the longitudinal axis of the shock absorber tube, whereby the free cross-section of the hydraulic oil flow openings in the pistons is changed.

[0006] DE 23 64 855 A1 discloses a shock absorber having a piston mounted on a piston rod. The piston consists of piston plates, one of which is rotatable about the piston rod. The piston rod is hollow. A rod is guided in the piston rod. The rod is connected to the piston plate. Openings, i.e., openings, are arranged in each of the piston plates, with the openings 6 being closed by spring-loaded valves.

[0007] US 4,964,492 A discloses a damping device with a solid body permeated with openings. A rotatable disc is arranged in the body. Openings of different diameters are arranged on a common circumference of the disc.

[0008] JP 2003-341332 A relates to a variable damping force suspension device supporting the front wheels of an automobile. A piston rod of a strut damper is mounted on a frame by ball bearings, and a damper body is attached to a wheel support. A first port, which generates a damping force during rebound, is formed on a piston. A control rod is provided that penetrates the piston rod in the axial direction, with the upper end of the control rod being attached to a wheel skirt. A damping force adjusting valve, which makes a throttle amount of the first port variable, is attached to the lower end of the control rod. Slits are provided on the damping force adjusting valve to increase the throttle amount of the first port when the front wheels are turned to predetermined steering angles.

[0009] DE 37 11 002 C1 describes a valve assembly for a telescopic vibration damper, a spring cylinder, or a level control system for the wheel suspension of motor vehicles. The valve assembly consists of a valve body with flow channels, two rotatably mounted control discs that interact with the flow channels, and a disc spring. The valve assembly has a valve body for each flow direction, and each valve body has at least two flow channels designated for one flow direction. These flow channels are spaced at different distances from the rotational axis of the valve body and open into annular grooves on one side of the valve body. The grooves are sealed by a disc spring.On the side of the valve body opposite the disc spring, a control disc is arranged. Each control disc has recesses that interact with the flow channels at the respective distance from the rotation axis, depending on the radial position of the flow channels. Each valve body contains a check valve for supplying pressure to the other valve body. The check valve has interacting holes in the disc spring, the valve body, and corresponding holes in the control discs, which are covered by a disc spring. The control discs are rotatable via a drive that runs inside the piston rod.

[0010] FR 1 602 000 A describes a hydraulic control device for lifting valves or plugs mounted on a shock absorber piston. The piston consists of a body drilled with pairs of transmission channels connected by a discharge channel. One of the channels of the pair is alternately equipped with a flow valve (shock) or a check valve (rebound) for the fluid. Plates are arranged on both sides of the piston. The plates have holes arranged alternately corresponding to a transmission channel equipped with a valve and a transmission channel without a valve of the following pair. The plates, integral with the piston body, have small-diameter openings opening into the channels equipped with valves and towards their rear, and are reset by a helical spring.Also described is an adjustment device comprising a column or sleeve surrounding the piston rod and having a disc as an integral part at one of its ends, which disc is supported on one of the plates rigidly connected to the piston body. The disc has groups of holes with a suitably increasing diameter, arranged in sectors within the radius of the transfer channels. The column or sleeve is equipped at its opposite end with a handling element with which the angular position of the disc can be varied. In order to vary the diameter of the inlet or outlet openings of the channels, the disc, which is integrated into the sleeve rotatably mounted on the piston rod, can be moved at a suitable angle with the aid of the handling element.

[0011] From US 2012 / 0 193 919 A1, for example, a shock absorber is known which has a piston guided axially in a cylinder tube, which divides the cylinder tube into a first and a second chamber. The piston comprises a piston housing in which connecting channels are provided through which a fluid present in the chambers can flow. The piston housing also has a rotatable rotor that can be driven by a control device external to the damper. The rotor has a spiral or blade-shaped structure so that the resistance of the fluid flowing past the rotor can be additionally increased or decreased by the rotation of the rotor. In this way, the damping force of the shock absorber can be changed and controlled depending on specific driving situations of a vehicle. A disadvantage of the piston-cylinder arrangement shown, however, is that the piston requires a relatively large amount of axial space.

[0012] Against this background, the object of the present invention is to provide a vibration damper, in particular a damping-adjustable shock absorber for motor vehicles, the damping force of which can be changed during its use, for example in a motor vehicle, and which, moreover, is particularly compact in the axial direction.

[0013] This object is achieved by a vibration damper having the features of claim 1.

[0014] A vibration damper, in particular a damping-adjustable shock absorber for motor vehicles, comprising a piston guided within a cylinder tube, axially displaceable therein, which is fastened to a piston rod, divides the cylinder tube into a first chamber and a second chamber and has connecting channels through which a damping fluid arranged in the chambers can flow, which extend from an end face of the piston facing the first chamber to an opposite end face of the piston facing the second chamber, wherein the flow-through connecting channels are each arranged distributed along circular circumferences with different radii, with openings of the connecting channels being arranged radially furthest inside on the end face of the piston facing an adjusting part, openings of the connecting or bypass channels being arranged radially furthest outside and openings of the connecting channels being arranged radially between the connecting channels, and where exactly one adjusting part is rotatably mounted on the piston rod parallel to the end faces of the piston, which adjusting part is rotationally symmetrical and which is spring-loaded in one direction of rotation, and which has through holes which are each distributed along a circular circumference with different radii, wherein the through holes assigned to the connecting or bypass channels of the piston are arranged radially further outwards than the through holes assigned to the connecting channels, and which is assigned to at least one connecting or bypass channel and through the rotation of which the flow cross section of each assigned connecting orBypass channel is changeable, wherein the adjusting part has a contact surface lying on one of the two end faces, which is penetrated by at least one through-bore opening on the one hand towards the end face and on the other hand towards the corresponding chamber, wherein the end-face-side opening of the through-bore in a first rotational position of the adjusting part has no overlap at all with the end-face-side opening of the connecting or bypass channel of the piston lying on the adjusting part and in a second rotational position of the adjusting part has complete overlap with the end-face-side opening of the connecting or bypass channel of the piston lying on the adjusting part.

[0015] Further particularly advantageous embodiments of the invention are disclosed in the subclaims.

[0016] It should be noted that the features listed individually in the following description can be combined with one another in any technically reasonable manner and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0017] As already mentioned, a vibration damper, in particular a damping-adjustable shock absorber for a motor vehicle, comprises a piston guided within a cylinder tube, axially displaceable therein, and attached to a piston rod. The piston divides the cylinder tube into a first chamber and a second chamber. Furthermore, the piston has connecting channels through which a damping fluid provided or arranged in the chambers can flow. The connecting channels extend from an end face of the piston facing the first chamber to an opposite end face of the piston facing the second chamber. The connecting channels have corresponding openings at the respective end faces.In addition, the vibration damper comprises precisely one adjusting part that can be rotated parallel to the end faces of the piston. This adjusting part is assigned to at least one connecting channel. By rotating the adjusting part, the flow cross-section of each associated connecting channel can be changed. In the context of the present invention, changing the flow cross-section includes both completely closing the connecting channel, in which no damping fluid can pass through the connecting channel, and completely opening the connecting channel, in which the damping fluid can flow through the connecting channel unhindered. Thus, the damping force of the proposed vibration damper can be changed or adjusted by varying the flow cross-sections of the respective connecting channels.The ability of the adjustment part to rotate parallel to the end faces of the piston also allows a particularly flat design of the adjustment part and thus of the piston as a whole with regard to the axial piston height, which also makes the vibration damper compact in the axial direction.

[0018] As also mentioned above, the adjusting part has a contact surface resting on one of the two end faces, which is penetrated by at least one through-bore opening on the one hand towards the end face and on the other hand towards the corresponding chamber. In a first rotational position of the adjusting part, the opening of the through-bore on the end face does not overlap at all with the opening of the connecting channel of the piston resting on the end face of the adjusting part. In a second rotational position of the adjusting part, it completely overlaps with the opening of the connecting channel of the piston resting on the end face of the adjusting part. Thus, by rotating the adjusting part, the connecting channel of the piston can be closed (first rotational position) or opened (second rotational position) towards the chamber of the cylinder tube on the side of the adjusting part.

[0019] According to an advantageous embodiment of the invention, the adjusting part is designed to assume any intermediate rotational position between the first rotational position and the second rotational position. In this way, the flow cross-section of the piston's connecting channel, and thus the damping force of the vibration damper, can be continuously varied or adjusted.

[0020] As explained above, exactly one adjustment part is provided. This is, as mentioned, rotationally symmetrical and rotatably mounted on the piston rod. Thus, in this design, the axis of rotation of the adjustment part is identical to the longitudinal axis of the piston. Furthermore, the through-bores of the adjustment part located on the end face of the piston, as well as the connecting channels of the piston assigned to the through-bores, are each distributed around a circle with the same radius. The center of these circles lies on the longitudinal axis of the piston. The key advantage of this design is that the flow cross-sections of several connecting channels can be influenced with just one adjustment part, which enables a particularly simple and compact shock absorber design.

[0021] Preferably, an electromagnetic actuator is provided or arranged on the adjustment part, which causes the adjustment part to rotate. As described above, the adjustment part is spring-loaded in one direction of rotation. The electromagnetic actuator is preferably an annular actuator, which consequently has only a small axial height. The spring loading of the adjustment part in one direction of rotation enables the use of a simple actuator that adjusts only in one direction of rotation. The return of the adjustment part can then be effected by the spring element providing the spring load.

[0022] Further features and advantages of the invention will become apparent from the following description of a non-limiting embodiment of the invention, which is explained in more detail below with reference to the drawing. In this drawing, schematically: Fig. 1 a partial cross-sectional view of a vibration damper according to the invention, Fig. 2 a plan view of an adjusting part of the vibration damper from Fig. 1, Fig. 3 a plan view of the adjusting part of the vibration damper from Fig. 1 facing end face of a piston, Fig. 4 a flow diagram during a compression stage of the vibration damper Fig. 1 with closed bypass channels, Fig. 5 a flow pattern during a rebound stage of the vibration damper Fig. 1 with closed bypass channels, Fig. 6 a flow diagram during a compression stage of the vibration damper from Fig. 1 with open bypass channels and Fig. 7 a flow pattern during a rebound stage of the vibration damper Fig. 1 with open bypass channels.

[0023] In the different figures, parts that are equivalent in terms of their function are always provided with the same reference symbols, so that they are usually only described once.

[0024] Fig. Figure 1 schematically illustrates, in a partial cross-sectional view, the basic structure of an embodiment of a vibration damper 1 according to the invention, in this case a damping-adjustable shock absorber for a motor vehicle. The shock absorber 1 has a piston 3 guided within a cylinder tube 2 and axially displaceable therein. The piston 3 is attached to a piston rod 4 and divides the cylinder tube 2 into a first chamber 5 and a second chamber 6. The chambers 5 and 6 are filled with a damping fluid, for example, oil.

[0025] How Fig. As can be seen from Figure 1, a sealing ring 7 is firmly attached to the circumferential surface of the piston 3. This enables the axial sliding of the piston 3 within the cylinder tube 2. In addition to supporting the sliding, the sealing ring 7 also prevents damping fluid from undesirably flowing between the inner wall of the cylinder tube 2 and the circumferential surface of the piston 3.

[0026] Furthermore, an annular spring assembly 10 and 11 are mounted on an end face 8 facing the first chamber 5 and on an opposite end face 9 facing the second chamber 6. The annular spring assembly 10 and 11 are in the Fig. 1, the shock absorber 1 is clamped against the respective end faces 8 and 9 by means of a screw nut 12.

[0027] Furthermore, the piston 3 has a plurality of different connecting channels 13, 14 and 15, which extend from the end face 8 facing the first chamber 5 to the end face 9 facing the second chamber 6. The connecting channels 13, 14 and 15 are each arranged on circles with different radii in the piston 3, as will be described below in connection with the description of the Fig. 3 will become even clearer. In principle, the connecting channels 13, 14, and 15 can be flowed through by the damping fluid present in chambers 5 and 6.

[0028] In particular, the first row of connecting channels 13, together with the annular spring assembly 10, provides the damping of a compression stage of the shock absorber 1, indicated by a dotted arrow 16, during which the piston 3 is pressed into the cylinder tube 2 via the piston rod 4, such as when a vehicle wheel is compressed. The second row of connecting channels 14, however, together with the annular spring assembly 11, provides the damping of a rebound stage of the shock absorber 1, indicated by the arrow 17, during which the piston 3 is pulled out of the cylinder tube 2 by the piston rod 4, such as when the vehicle wheel rebounds. The functioning of the connecting channels 13 and 14 in combination with the respective annular spring assemblies 10 and 11 during the compression and rebound stages 16 and 17, respectively, of the shock absorber 1 is generally known and will not be described further here.The third row of connecting channels 15 provides so-called bypass channels through which the damping fluid can flow under certain operating conditions of the shock absorber 1, explained below, in addition to flowing through the connecting channels 13 and 14, respectively.

[0029] The flow of the damping fluid through the connecting or bypass channels 15 is Fig. 1 is controlled by means of an adjusting part 18 which is rotatable parallel to the end faces 8 and 9 of the piston 3. In the present case, exactly one adjusting part 18 is provided, which is rotationally symmetrical and has through holes 20 running parallel to the longitudinal axis 19 of the piston 3 and arranged along a circular circumference. As shown in Fig. 1, the radius of the circumference along which the through-bores 20 of the adjusting part 18 are arranged corresponds to the radius of the circumference along which the connecting channels 15 of the piston 3 are arranged. The centers of both circles also lie on the longitudinal axis 19 of the piston 3. Thus, both circles are congruent, and the through-bores 20 are correspondingly assigned to the connecting channels 15.

[0030] In order to be able to control the flow cross-section of the connecting or bypass channels 15 assigned to the through-bores 20 by rotating the adjusting part 18, the adjusting part 18, in the case shown here, has a contact surface resting on the end face 8, which is penetrated by the through-bores 20 in such a way that the through-bores 20 open, on the one hand, toward the end face 8 of the piston 3 and, on the other hand, toward the chamber 5. Thus, depending on the rotational position of the adjusting part 18, the through-bores 20 can be brought into no, partial, or complete overlap with the connecting channels 15 of the piston 3.In particular, the adjusting part 18 can be rotated at least into a first rotational position in which the end-face openings of the through-bores 20 have no overlap at all with the end-face openings of the connecting channels 15 of the piston 3 adjacent to the adjusting part 18, and into a second rotational position in which the end-face openings of the through-bores 20 have complete overlap with the end-face openings of the connecting channels 15 of the piston 3 adjacent to the adjusting part 18. In this way, the flow of the damping fluid through the connecting or bypass channels 15 can be controlled, or at least switched on and off, both during the compression and rebound stages of the shock absorber.

[0031] In other words, the Fig. 1, the damping fluid in the first rotational position of the adjusting part 18 during the compression or rebound stage of the shock absorber 1 does not flow through the connecting or bypass channels 15 in the piston 3 between the chambers 5 and 6, but only through the connecting channels 13 and 14. In the second rotational position of the adjusting part 18, however, the damping fluid can also flow through the connecting or bypass channels 15 between the chambers 5 and 6 during the compression or rebound stage of the shock absorber 1, whereby the flow resistance opposite the piston 3 and thus the damping force provided by the shock absorber 1 is reduced.

[0032] As in Fig. 1, the adjusting part 18 is rotatably mounted on the piston rod 4 to enable its rotation parallel to the end face 8 of the piston 3 or about the longitudinal axis 19 of the piston 3. In particular, an electromagnetic actuator 21 is provided on the adjusting part 18 of the shock absorber 1, with the aid of which the adjusting part 18 can be rotated. The actuator is preferably an annular actuator, since this has only a small axial height and thus enables a compact design of the arrangement comprising piston 3 and adjusting part 18 and thus of the piston-cylinder arrangement 1 as a whole, i.e. of the shock absorber 1, in the axial direction of the piston 3. Furthermore, the adjusting part 18 in the presently illustrated case is spring-loaded in one direction of rotation by means of a spring element 22. The spring loading of the adjusting part 18 in one direction of rotation enables the use of an actuator that adjusts only in one direction of rotation.The return of the adjustment part 18 is effected by the spring element 22 providing the spring load.

[0033] In order to enable the flow of the damping fluid between the chambers 5 and 6 through the connecting channels 13 and 14 during a compression and rebound stage of the shock absorber, the adjusting part 18 further has a series of further through-bores 23, which are also arranged distributed over a circular circumference in the adjusting part 18.

[0034] Fig. 2 shows a plan view of the adjustment part 18 of the vibration damper 1 Fig. 1 as seen from above. It can be clearly seen how the through-bores 20 and 23 are each arranged distributed along a circular circumference with different radii, wherein the through-bores 20 assigned to the connecting or bypass channels 15 of the piston 3 are arranged radially further outwards than the through-bores 23 assigned to the connecting channels 13 and 14.

[0035] Fig. 3 shows a plan view of the adjusting part 18 of the vibration damper 1 Fig. 1 facing end face 8 of the piston 3. Here, too, it can be seen that the connecting channels 13, 14 and 15 are each arranged distributed along circular circumferences with different radii, wherein the openings of the connecting channels 13 are arranged radially furthest inside on the end face 8 of the piston 3 facing the adjusting part 18, the openings of the connecting or bypass channels 15 are arranged radially furthest outside and the openings of the connecting channels 14 are arranged radially between the connecting channels 13 and 15.

[0036] The Fig. 4 to 7 show flow patterns through the arrangement of piston 3 and adjusting part 18 of the Fig. 1 shown shock absorber 1.

[0037] Fig. 4 shows a flow diagram during a pressure stage 16 of the vibration damper 1 Fig. 1 with connecting or bypass channels 15 closed by the adjusting part 18. As shown in Fig. As can be seen from the flow arrows shown in Figure 4, the damping fluid flows at the pressure stage 16 from the chamber 6 through the connecting channels 13, the annular spring assembly 10 and the through holes 23 into the chamber 5.

[0038] Fig. 5 shows a flow pattern during a rebound stage 17 of the vibration damper 1 Fig. 1 with connecting or bypass channels 15 closed by the adjusting part 18. As shown in Fig. As can be seen from the flow arrows shown in Figure 5, the damping fluid flows at the pressure stage 17 from the chamber 5 through the through holes 23, the connecting channels 14 and the annular spring assembly 11 into the chamber 6.

[0039] Fig. 6 shows a flow diagram during a pressure stage 16 of the vibration damper 1 Fig. 1 with connecting or bypass channels 15 opened by the adjusting part 18. In addition to the Fig. 4 shown flow through the connecting channels 13, the ring spring assembly 10 and the through holes 23, the damping fluid flows in the Fig. 6, also from the chamber 6 through the connecting or bypass channels 15 and the perforations 20 into the chamber 5.

[0040] Fig. 7 shows a flow pattern during a rebound stage 17 of the vibration damper 1 Fig. 1 with connecting or bypass channels 15 opened by the adjusting part 18. In addition to the Fig. 5 shown flow through the through holes 23, the connecting channels 14 and the annular spring assembly 11, the damping fluid flows in the Fig. 7, also from chamber 5 through the perforations 20 and the connecting or bypass channels 15 into chamber 6.

[0041] The damping force provided by the shock absorber 1 is in the ranges shown in the Fig. 4 and Fig. 5 shown cases due to the closed connecting or bypass channels 15 larger than in the Fig. 6 and Fig. 7, in which the connecting or bypass channels 15 can additionally be flowed through by the damping fluid.

[0042] The vibration damper according to the invention has been explained in more detail using an exemplary embodiment illustrated in the figures. The vibration damper according to the invention described above is not limited to the embodiment disclosed herein, but also encompasses other embodiments with the same effect. In particular, it is conceivable that the adjusting part can assume any desired intermediate rotational position between the first and second rotational positions described above. In this way, the flow cross-section and thus the flow resistance acting against the piston can be continuously varied during the compression and rebound stages of the shock absorber.

[0043] In a preferred embodiment, the vibration damper according to the invention is used as a damping-adjustable shock absorber on a wheel suspension of a motor vehicle for damping the compression and rebound movements of the wheel rotatably held by the wheel suspension. List of reference symbols: 1 vibration damper 2 cylinder tube 3 pistons 4 piston rod 5 First Chamber 6 Second Chamber 7 Sealing ring 8 End face facing 5 9 End face facing 6 10 ring spring package 11 Ring spring package 12 screw nut 13 connecting channel 14 connecting channel 15 connecting channel 16 pressure levels 17 rebound 18 Adjustment part 19 Longitudinal axis of 3 20 through holes 21 Actuator 22 Spring element 23 Through hole X First spatial direction Y Second spatial direction Z Third spatial direction

Claims

[1] Vibration damper (1) for motor vehicles, comprising a piston (3) guided within a cylinder tube (2) and axially displaceable therein, which is fastened to a piston rod (4), divides the cylinder tube (2) into a first chamber (5) and a second chamber (6) and has connecting channels (13, 14, 15) through which a damping fluid arranged in the chambers (5, 6) can flow, which extend from an end face (8) of the piston (3) facing the first chamber (5) to an opposite end face (9) of the piston (3) facing the second chamber (6), wherein the flow-through connecting channels (13, 14, 15) are each arranged distributed along circular circumferences with different radii, wherein openings of the connecting channels (13) are arranged radially furthest inside on the end face (8) of the piston (3) facing an adjusting part (18), the openings of the connecting or bypass channels (15) are arranged radially furthest outside and openings of the connecting channels (14) are arranged radially between the connecting channels (13, 15), and where exactly one adjusting part (18) is rotatably mounted on the piston rod (4) parallel to the end faces (8, 9) of the piston (3), which adjusting part is rotationally symmetrical and which is spring-loaded in one direction of rotation, and which has through-bores (20, 23) which are each distributed along a circular circumference with different radii, wherein the through-bores (20) assigned to the connecting or bypass channels (15) of the piston (3) are arranged radially further outwards than the through-bores (23) assigned to the connecting channels (13, 14), and which is assigned to at least one connecting or bypass channel (15) and by the rotation of which the flow cross-section of each assigned connecting or bypass channelBypass channel (15) is variable, wherein the adjusting part (18) has a contact surface lying on one of the two end faces (8) and is penetrated by at least one through-bore (20) opening on the one hand towards the end face (8) and on the other hand towards the corresponding chamber (5), wherein the end-face-side opening of the through-bore (20) in a first rotational position of the adjusting part (18) has no overlap at all with the end-face-side opening of the connecting or bypass channel (15) of the piston (3) lying on the adjusting part (18) and in a second rotational position of the adjusting part (18) has complete overlap with the end-face-side opening of the connecting or bypass channel (15) of the piston (3) lying on the adjusting part (18). [2] Vibration damper (1) according to claim 1, characterized bythat the adjusting part (18) is designed to assume any intermediate rotational position between the first rotational position and the second rotational position. [3] Vibration damper (1) according to claim 1 or 2, characterized by that the through-bores (20) of the adjusting part (18) adjacent to the end face (8) of the piston (3) and the connecting or bypass channels (15) of the piston (3) assigned to the through-bores (20) are each arranged distributed over a circular circumference with the same radius, the center of which lies on the longitudinal axis (19) of the piston (3). [4] Vibration damper (1) according to one of the preceding claims, characterized by that an electromagnetic actuator (21) is arranged on the adjusting part (18) which causes the rotation of the adjusting part (18). [5] Vibration damper (1) according to one of the preceding claims, which is a damping-adjustable shock absorber.

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