Vibration damper for motor vehicle

Abstract

The invention relates to a damper (10) for a vehicle, comprising a damper cylinder (14) filled with a hydraulic fluid, a working piston (18) connected to a piston rod (20) and arranged in the damper cylinder (14) so as to be movable back and forth, the interior of the damper cylinder (14) being divided by the working piston (18) into a first working chamber (22) and a second working chamber (24), a rebound stop device (28) comprising an auxiliary piston (30), the auxiliary piston coaxially surrounds the piston rod (20); and a spring-back stop receptacle (40), in particular in the form of a sleeve, mounted on the damper cylinder (14) for receiving the auxiliary piston (30) during a spring-back phase; wherein the auxiliary piston (30) is mounted on the piston rod (20) and is axially displaceable relative thereto, and the spring-back stop (28) has an elastic element (44) which is fastened to the auxiliary piston (30).

Description

[0001] The invention relates to a motor vehicle shock absorber with a rebound stop device.

[0002] Known hydraulic shock absorbers (e.g., patent DE 101 05 101 C1) include a hydraulic rebound stop. Hydraulic rebound stops are usually used to provide an additional damping effect in the end region of the rebound phase of the shock absorber. To this end, in the known shock absorber, when the piston rod moves in the rebound direction, an auxiliary piston enters the rebound stop chamber, thereby generating an additional damping effect. Components involved in rebound damping usually require very precise manufacturing tolerances, for example in order to compensate for transverse forces acting on the piston rod. As a result, the manufacturing costs of these components are usually very high.

[0003] Based on this, the object of the present invention is to provide a shock absorber with a rebound stop device, which can achieve a reliable damping effect through the rebound stop device, and at the same time the manufacturing cost of the rebound stop device should be low.

[0004] This object is achieved according to the invention by a vibration damper having the features of claim 1. Preferred developments are described in the dependent claims.

[0005] According to a first aspect, the present invention provides a shock absorber for a vehicle, comprising a shock absorber cylinder filled with hydraulic fluid and a working piston connected to a piston rod, the working piston being arranged in the shock absorber cylinder and being reciprocatingly movable. The interior of the shock absorber cylinder is divided by the working piston into a first working chamber on a side close to the piston rod and a second working chamber on a side away from the piston rod. In particular, the shock absorber further comprises a closing assembly for fluid-tightly closing the shock absorber cylinder on one side of the piston rod. In addition, the shock absorber further comprises a rebound stop device, which has an auxiliary piston, which concentrically surrounds the piston rod and has a rebound stop receptacle, in particular a sleeve-shaped, which is mounted on the shock absorber cylinder for accommodating the auxiliary piston during the rebound phase. The auxiliary piston is axially movable relative to the piston rod. The rebound stop device further comprises an elastic element fixed to the auxiliary piston. The elastic element is preferably mechanically arranged in series with the auxiliary piston.

[0006] The axial mobility of the auxiliary piston relative to the piston rod mechanically decouples the two elements from each other. Furthermore, the elastic element is additionally fixed to the auxiliary piston, ensuring that the elastic element is mechanically arranged in series with the auxiliary piston. When the piston rod moves in the rebound direction, the auxiliary piston also moves in the rebound direction and together with the elastic element arranged in series provides a damping effect for the rebound direction movement of the piston. In particular, when the auxiliary piston enters the rebound stop receptacle, the auxiliary piston provides a damping effect on the movement of the piston rod. The additionally arranged elastic element in series allows the use of a shorter length of the rebound stop receptacle, since even a shorter auxiliary piston damping stroke is sufficient. This reduces costs and simplifies the assembly process. Furthermore, in particular due to the series arrangement, the hydraulic rebound stop has a smoother response characteristic. In particular, the series arrangement of the elastic element with the auxiliary piston results in progressive damping, i.e. the damping force of the rebound stop increases with increasing piston speed.

[0007] The elastic element preferably serves to additionally damp the movement of the piston rod in the rebound direction. In particular, the elastic element is mounted axially relative to the piston rod and can be displaced. The fastening of the elastic element to the auxiliary piston also has the effect that the elastic element can be guided axially and that the elastic element is centered on the piston rod.

[0008] The shock absorber can be a single tube shock absorber or a multi-tube shock absorber. For example, a multi-tube shock absorber for a vehicle comprises an outer tube and an inner tube arranged coaxially with the outer tube, wherein a balance chamber is formed between the outer tube and the inner tube for accommodating a hydraulic fluid, a working piston is connected to a piston rod and arranged in the inner tube so as to be reciprocating, and the interior of the inner tube is divided into a first working chamber and a second working chamber by the working piston. The balance chamber is preferably at least partially filled with gas, in particular at its upper end. The outer tube preferably at least partially forms the housing of the shock absorber. The inner surface of the inner tube is preferably processed as a guide for the working piston. The working piston preferably comprises a valve device, by which the first and second working chambers are connected to each other. In particular, the inner tube has at least one passage opening for connecting a first working chamber near the piston rod with the annular chamber fluid, the passage opening being located in the first working chamber. In a single tube shock absorber, preferably no outer tube is provided. The inner tube is preferably referred to as a damping cylinder, which accommodates the piston rod and the working piston, as described above.

[0009] For a multi-tube shock absorber, the shock absorber comprises in particular a closure assembly which is designed and arranged to seal the internal fluid of the outer tube on the piston rod side. The end of the inner tube on the piston rod side is preferably fixed to the closure assembly. At the end opposite to the closure assembly and away from the piston rod, the interior of the outer tube is preferably sealed from the fluid by a bottom assembly. In particular, a bottom valve is provided on the bottom assembly, which is in particular mounted at the end of the inner tube away from the piston rod. The second working chamber is preferably connected to the balance chamber fluid via the bottom valve. The bottom valve is preferably a one-way valve through which the fluid can flow in both directions or only in one direction. For example, in the rebound direction of the piston moving outward from the inner tube, the bottom valve is designed as a one-way valve; in the compression direction of the piston moving toward the inner tube, the bottom valve is designed as a characteristic-defining valve.

[0010] In the case of a monotube shock absorber, the shock absorber comprises in particular a closure assembly which is designed and arranged to seal the interior of the shock absorber cartridge fluidically on the piston rod side. The end of the shock absorber cartridge on the piston rod side is preferably fixed to the closure assembly. At the end opposite to the closure assembly and remote from the piston rod, the interior of the shock absorber cartridge is preferably fluidically sealed by an axially movable sealing element. The sealing element preferably separates an axially adjacent gas space from a working chamber filled with hydraulic fluid. For example, the shock absorber has no bottom valve and comprises only a bottom assembly, wherein the bottom assembly forms a fluid-tight closure of the shock absorber cartridge and an adjustment valve is provided outside the shock absorber cartridge, which adjustment valve produces a damping effect, for example, in the compression direction. It is conceivable, in particular in a monotube shock absorber, to replace the bottom assembly with a separating piston which separates the working chamber remote from the piston rod from the gas space.

[0011] In the following description, the term "shock absorber" is understood to include multi-tube shock absorbers and single-tube shock absorbers, wherein the shock absorber tube refers to the inner tube of the multi-tube shock absorber. In the following, "movement in the rebound direction" is understood to be movement toward the closing component and into the area on the side of the shock absorber piston rod; "movement in the compression direction" is understood to be movement toward the bottom valve and into the area of ​​the shock absorber away from the piston rod. The closing component is preferably arranged coaxially with the piston rod and surrounds the periphery of the piston rod.

[0012] The shock absorber comprises a rebound stop device, which is designed to provide an additional damping effect for the piston movement during the rebound phase. The rebound stop device preferably comprises an auxiliary piston, a rebound stop chamber and a rebound stop receptacle. The rebound stop chamber is preferably formed as an annular chamber between the piston rod and the rebound stop receptacle in the first working chamber. The rebound stop receptacle is, for example, sleeve-shaped, in particular cylindrical, and preferably has a diameter smaller than the diameter of the inner tube. The rebound stop receptacle is preferably in fluid-tight contact with the inner wall of the shock absorber cylinder. For example, the rebound stop receptacle is made of plastic material or metal.

[0013] The auxiliary piston is fixed to the piston rod and can move axially relative to the piston rod. The auxiliary piston is, for example, installed in front of the working piston and located in the compression direction. The auxiliary piston is preferably arranged between the closing assembly and the working piston. The axial movement range of the working piston in the damping cylinder is preferably set so that only the auxiliary piston but not the working piston can enter the rebound stop chamber.

[0014] For example, the auxiliary piston comprises a plurality of or exactly one annular area which is arranged coaxially with respect to the piston rod and is movable with respect to the piston rod. The auxiliary piston is preferably designed such that when the piston rod moves in the rebound direction, the auxiliary piston at least partially closes the rebound stop chamber in a fluid-tight manner, wherein the auxiliary piston preferably has a channel to allow a fluid to flow through the auxiliary piston.

[0015] In the first embodiment, one end of the elastic element is mounted on the auxiliary piston, and the other end is connected to the fixed position of the piston rod via a fixed seat, and the auxiliary piston is preferably arranged on one side of the rebound direction of the fixed seat. The fixed seat is preferably arranged between the working piston and the bottom valve. The elastic element is preferably designed as a coil spring.

[0016] The elastic element is preferably fixedly connected to the piston rod via a fixing seat, so that the end of the elastic element facing the compression direction moves with the piston rod, while the end facing the rebound direction is movable relative to the piston rod and moves with the auxiliary piston. This ensures that the elastic element can be activated, in particular compressed, after the auxiliary piston enters the rebound stop receiving portion.

[0017] In another embodiment, the rebound stop device has a sealing ring between the auxiliary piston and the piston rod, which is used to seal the auxiliary piston from the piston rod. This prevents the flow of fluid between the auxiliary piston and the piston rod. In particular, it ensures that the hydraulic fluid can only be discharged from the rebound stop chamber through the gap of the piston ring, in particular into the first working chamber.

[0018] In another embodiment, the sealing ring is mounted to be axially movable relative to the piston rod. The sealing ring is preferably mounted on the piston rod so as to be relatively slidable in the axial direction.

[0019] In another embodiment, the sealing ring is mounted on the auxiliary piston so as to be fixed in position relative to the piston rod. For example, a gap is formed between the piston rod and the auxiliary piston, which gap preferably allows relative movement. The sealing ring moves together with the auxiliary piston to ensure reliable sealing of the gap.

[0020] In another embodiment, the auxiliary piston has a first piston area and a second piston area, wherein the sealing ring is in close contact with the first and second piston areas. The sealing ring is preferably in close contact with the radially inward surface of each piston area. Preferably, the auxiliary piston is preferably composed of two parts and has a first piston area and a second piston area, which are respectively mounted on the piston rod and can be moved relative to the piston rod. The two-part form makes it possible to easily mount the auxiliary piston on the piston rod. The piston areas are, for example, annular in form and are preferably in close contact with each other or connected to each other.

[0021] The sealing ring is preferably arranged circumferentially around the piston rod and coaxial with the piston rod. In particular, the sealing ring is close to the inner surface of the second piston area, preferably located between the piston rod and the second piston area, for example, radially spaced from the second piston area. The inner surface of the second piston area preferably has a radially inward protrusion, which forms an axial support surface of the sealing ring for fluid-tight support of the sealing ring and the support surface of the second piston area. In addition, the sealing ring also particularly abuts against the first piston area, preferably against the end face of the first piston area. The sealing ring is preferably close to the installation area of ​​the first piston area. In particular, the sealing ring is tightly fitted at least to the piston rod, the first piston area and the second piston area.

[0022] In another embodiment, a piston ring is arranged between the first piston area and the second piston area, and the piston ring is installed between the first piston area and the second piston area and can move axially relative to the first piston area and the second piston area. The piston ring is preferably designed as a C-shaped ring with an opening. The piston ring can be installed axially and movably in particular.

[0023] In particular, the second piston region has a circumferential groove which opens in the direction of the first piston region. The piston ring is preferably mounted in the groove. The axial length of the piston ring is preferably smaller than the axial length of the groove, so that the piston ring is preferably mounted movably in the axial direction relative to the first and second piston regions. In particular, the movement of the piston ring is limited in the impact direction by the first piston region and in the rebound direction by the second piston region.

[0024] The outer diameter of the first piston zone and the outer diameter of the second piston zone are preferably smaller than the inner diameter of the rebound stop chamber, so that the hydraulic fluid can flow between the first piston zone, the second piston zone and the rebound stop chamber. The outer diameter of the piston ring preferably corresponds to the inner diameter of the rebound stop chamber and forms a fluid seal therewith. In particular, the inner diameter of the piston ring is larger than the inner diameter of the recess of the second piston zone, so that the hydraulic fluid can flow between the piston ring and the first and / or second piston zone. The auxiliary piston preferably has a bypass channel, which is formed between the inner diameter of the piston ring and the first and / or second piston zone, in particular extending on the circumference, preferably extending on the entire circumference. The bypass channel forms a fluid connection between the rebound stop chamber and the first working chamber, which is arranged along the compression direction of the auxiliary piston.

[0025] The auxiliary piston is preferably designed to be able to move the piston ring from an open position, in which the bypass channel is in particular completely open, to a closed position, in which the flow diameter of the bypass channel is reduced relative to the open position, in particular it is at least partially or completely closed by the piston ring. Preferably, in the closed position, the bypass channel is preferably completely formed by the opening of the piston ring, which forms a C-shaped ring.

[0026] In another embodiment, the first piston area and the second piston area are connected to each other by an interlocking, frictional and / or material-to-material adhesive connection. In particular, the first and second piston areas are immovable relative to each other.

[0027] In another embodiment, the first piston area has a mounting area for mounting the first piston area on the second piston area, wherein the mounting area has a plurality of at least partially radially inwardly directed connecting protrusions which interact with the cutouts of the second piston area to form an interlocking and / or frictional connection, in particular a snap-on connection.

[0028] The mounting area preferably forms one end of the first piston area, which points in the direction of the second piston area. The angle between the connecting protrusion and the axial direction in the direction of the piston rod is about 10 to 60°, preferably 20 to 40°, and in particular 30°. For example, the mounting area includes a plurality of arms extending in the axial direction, each of which has at least one connecting protrusion formed on it. In particular, the second piston area has a cutout, in particular an annular groove, with which the connecting protrusion engages. The connecting protrusion preferably forms a snap connection with the cutout of the second piston area. In particular, the second piston area has an axial support surface, which points in the direction of the elastic element and abuts against the elastic element. The support surface is, for example, planar.

[0029] In another embodiment, the rebound stop device comprises a rebound stop chamber, which is formed between the rebound stop housing, the auxiliary piston and the closure assembly, and the rebound stop chamber is only fluidically connected to the first working chamber. The rebound stop chamber is preferably defined by the rebound stop housing, the auxiliary piston and the closure assembly. The rebound stop chamber is preferably only hydraulically connected to the first working chamber and the piston rod-side working chamber. The closure assembly is preferably capable of completely closing the rebound stop chamber, so that the hydraulic fluid flows from the rebound stop chamber exclusively into the first working chamber, in particular only through the auxiliary piston, preferably through the bypass channel.

[0030] In another embodiment, at least a portion of the elastic element is arranged in the rebound stop chamber. In particular, during the rebound phase of the shock absorber, the elastic element is arranged in the rebound stop chamber.

[0031] In another embodiment, the auxiliary piston has a connection area for connecting the auxiliary piston and the elastic element, wherein the elastic element is connected to the connection area of ​​the auxiliary piston by interlocking and / or friction connection, in particular press fit. The auxiliary piston preferably forms a seat for the elastic element so that the elastic element and the auxiliary piston interact reliably. When the auxiliary piston moves in the rebound direction, the elastic element can provide additional damping for the auxiliary piston, thereby preventing the auxiliary piston from colliding with the end area of ​​the damper, in particular the closed component. The connection area, for example, has a profile structure. The profile structure is preferably formed on the outer periphery and / or inner periphery of the connection area. The role of the profile structure is to provide a more secure connection, in particular a press-fit connection, between the connection area of ​​the auxiliary piston and the elastic element. The profile structure preferably includes a plurality of protrusions located on the inward circumferential surface, wherein the protrusions are, for example, evenly spaced from each other, in particular extending axially or radially.

[0032] The elastic element is preferably a helical spring, wherein the inner diameter of the helical spring is smaller than the outer diameter of the connection area of ​​the auxiliary piston. The elastic element is preferably pressed or clamped on the connection area of ​​the auxiliary piston. In particular, at least one or two windings are fixed to the connection area. In particular, the end of the elastic element opposite the auxiliary piston is fixed to a mounted seat so as to be fixed in position. For example, when the piston rod moves in the rebound direction, the closing component forms an axial stop for the auxiliary piston. The elastic element is preferably fixed to the seat in a fixed position. The seat is preferably arranged coaxially with the piston rod, in particular fixed to the piston rod.

[0033] For example, the connecting region is adjacent to a region with a larger diameter than the connecting region in the direction of the first piston region, which region forms an axial bearing surface for the elastic element. When the auxiliary piston moves in the rebound direction, the elastic element preferably bears on this bearing surface. The bearing surface preferably points in the rebound direction and is in particular in the form of a plane.

[0034] For example, the second piston region of the auxiliary piston is formed from a plastic material. The second piston region is preferably formed by plastic injection molding. Such a piston region can be manufactured particularly cheaply. In contrast to the first piston region, the second piston region is preferably made only of plastic material, which piston region is located in the compression direction. During operation of the shock absorber, the loads acting on this region of the auxiliary piston are small, so that this region can be made of a less expensive material, such as plastic. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following text describes the present invention in more detail through multiple exemplary embodiments in conjunction with the accompanying drawings.

[0036] The present invention will be discussed in more detail below based on a number of exemplary embodiments and with reference to the accompanying drawings.

[0037] Figure 1 is a schematic longitudinal cross-sectional view of a shock absorber according to an exemplary embodiment.

[0038] Figure 2 is a schematic longitudinal sectional detail view of a shock absorber according to another exemplary embodiment.

[0039] Figure 3 is a schematic detail view of a shock absorber in a longitudinal sectional view according to another exemplary embodiment.

[0040] Figure 1 The shock absorber 10 is shown, where the shock absorber 10 is, for example, a multi-tube shock absorber, such as a twin-tube shock absorber. The shock absorber 10 has an outer tube 12, which forms the outer surface of the shock absorber 10, in particular the housing. Inside the outer tube 12 and arranged coaxially with the outer tube 12 is a shock absorber cylinder 14, also referred to as the inner tube 14. A balance chamber 16 is formed between the outer tube 12 and the inner tube 14, and this chamber is preferably at least partially or completely filled with a hydraulic fluid. For example, the balance chamber 16 is partially filled with gas.

[0041] The working piston 18 is connected to the piston rod 20 and is arranged inside the inner tube 14 so as to be movable inside the inner tube 14, where the inner tube 14 is preferably formed as a guiding device for the working piston 18. The working piston 18 preferably has a valve device. For example, the valve device includes a rebound stage valve for damping the movement of the piston during the rebound stage, and a compression stage valve for damping the movement of the piston during the compression stage. Each valve preferably consists of a channel opening passing through the piston and a valve disc assembly. The working piston 18 divides the interior of the inner tube 14 into a first working chamber 22 on the piston rod side and a second working chamber 24 remote from the piston rod. The piston rod 20 can preferably be connected to the vehicle body through one end thereof extending out of the shock absorber cylinder 14.

[0042] The interior of the outer tube 12 is fluid-sealed on the piston rod side by a sealing assembly 34. Opposite the sealing assembly 34, i.e., at the end remote from the piston rod, the interior of the outer tube 12 is fluid-sealed by a base 36. For example, a base valve 38 is installed on the base 36, and this base valve is particularly installed at the end of the inner tube 14 remote from the piston rod. The base valve 38 is preferably a check valve, and the fluid can pass through in both directions or only in one direction. The second working chamber 24 is preferably fluid-connected to the balance chamber 16 through the base valve 38. The piston rod side end of the inner tube 14 is preferably fixed to the sealing assembly 34.

[0043] For example, the end region of the outer tube 12 on the piston rod side is surrounded by a cap or seal 26. The cap or seal 26 preferably forms an end member of the outer tube 12 and a closure with respect to the piston rod 20.

[0044] The shock absorber 10 further comprises a rebound stop device 28 for providing additional damping for the piston movement in the rebound direction Z during the rebound phase. For example, the rebound stop device 28 comprises an auxiliary piston 30, a rebound stop chamber 32 and a rebound stop receptacle 40. The auxiliary piston 30 is preferably mounted on the piston rod 20 so that it can move in the axial direction. In the rebound direction Z, the auxiliary piston 30 is mounted in front of the working piston 18 so that when the piston rod 20 moves in the rebound direction Z, i.e. in the direction away from the shock absorber cylinder 14, the auxiliary piston 30 enters the rebound stop chamber 32 before the working piston 18 enters the rebound stop chamber 32. The axial movement range of the working piston 18 in the shock absorber cylinder 14 is preferably set so that only the auxiliary piston 30 but not the working piston 18 can enter the rebound stop chamber 32. The rebound stop receptacle 40 is preferably mounted in the end region of the shock absorber cylinder 14 pointing in the rebound direction Z, for example fixed by being connected to the closure component 34. The rebound stop chamber 32 is preferably formed between the rebound stop receptacle 40, the auxiliary piston 30 and the closure assembly 34 and is preferably defined by them. The rebound stop chamber 32 is preferably only hydraulically connected to the first working chamber 22, i.e., the working chamber 22 on the side close to the piston rod. The closure assembly 34 preferably completely fluid-tightly closes the rebound stop chamber 32, so that the hydraulic fluid can only flow from the rebound stop chamber 32 to the first working chamber 22, in particular only through the auxiliary piston 30.

[0045] The rebound stop chamber 32 is formed in an annular chamber between the piston rod 20 and the rebound stop receptacle 40. The rebound stop receptacle 40 is, for example, sleeve-shaped, in particular cylindrical, with a diameter that is smaller than the diameter of the inner tube 14. The rebound stop receptacle 40 preferably rests against the inner wall of the inner tube 14 in a fluid-tight manner. For example, the rebound stop receptacle 40 is made of a plastic material or metal. For example, the inner diameter and / or outer diameter of the rebound stop receptacle 40 is constant. The damping cylinder 14 has an inner diameter and / or outer diameter that is, in particular, constant.

[0046] The rebound stop device 28 further comprises an elastic element 44, in particular a helical spring. The elastic element 44 is coaxially arranged around the piston rod 20. The inner diameter of the elastic element 44 is preferably equal to or greater than the outer diameter of the piston rod 20, and the outer diameter of the elastic element 44 is equal to or less than the inner diameter of the inner tube 14, in particular the inner diameter of the rebound stop receptacle 40. The elastic element 44 is preferably movable in the axial direction relative to the piston rod 20. For example, one end of the elastic element 44 is supported on the auxiliary piston 30, and the other end thereof is supported on the seat 42. The seat 42 is, for example, fixedly connected to the elastic element 44 and is preferably coaxially arranged on the piston rod 20. In particular, the fixed seat 42 is mounted on the piston rod 20 in a fixed position. The closure assembly 34 forms, for example, an upper stop for the movement of the elastic element 44 and the auxiliary piston 30 in the rebound direction Z. The seat 42 preferably rests on the piston rod 20 in a fixed position when the piston rod 20 moves in the rebound direction Z. The outer diameter of the seat 42 is preferably smaller than the inner diameter of the inner tube 14 so that hydraulic fluid can flow between the inner tube and the seat 42. The outer diameter of the seat 42 is preferably small enough that it creates negligible flow resistance during piston movement.

[0047] Figure 2 and Figure 3 A more detailed schematic diagram of the auxiliary piston 30 is shown. The auxiliary piston 30 has a first piston region 46, in particular an annular piston region, which is mounted on the piston rod 20 and can move axially so that the piston region 46 can move relative to the piston rod 20, in particular slide axially relative to the piston rod 20.

[0048] The first piston area 46 preferably forms the end of the auxiliary piston 30 pointing toward the closure assembly 34. In the compression direction D, the first piston area 46 is adjacent to the second piston area 48. The piston areas 46 and 48 are arranged coaxially relative to the piston rod 20 and are preferably mounted so as to be able to move axially. For example, at least one surface of the second piston area 48 is in contact with the first piston area 46. In particular, the first and second piston areas 46 and 48 each have an axial stop surface that abuts against each other. The second piston area 48 is preferably connected to the first piston area by form fit, material bonding and / or friction. For example, the first piston area 46 is connected to the second piston area 48 by an interference fit or a clamping connection. The first piston area 46 preferably has an annular groove 50, which forms a pressure fit with the first piston area 46, preferably the lower end area of ​​the first piston area. The second piston area 48 preferably has an inner diameter that is greater than the outer diameter of the piston rod 20, so that the second piston area 48 can move relative to the piston rod 20. A piston ring 52 is arranged between the first and second piston areas 46 and 48. The piston ring 52 is, for example, a C-shaped ring having an opening 62 .

[0049] For example, the first piston area 46 has an outer diameter area that exceeds the second piston area 48 in the radial direction, and the area preferably forms an axial bearing surface for the piston ring 52. The outer diameters of the first piston area 46, the second piston area 48 and the piston ring 52 are preferably smaller than the inner diameter of the inner tube 14 at any point, thereby forming a fluid channel between the inner tube 14 and the first and second piston areas 46, 48 and the piston ring 52.

[0050] In particular, the second piston region 48 forms the end of the auxiliary piston 30 pointing toward the bottom valve 38. For example, the second piston region 48 has a connecting region 54 at the end close to the bottom valve for connecting the second piston region 48 to the elastic element 44. In particular, the diameter of the connecting region 54 is smaller than the diameter of the rest of the second piston region 48. The connecting region 54 preferably has an outer diameter that corresponds to or is larger than the inner diameter of the elastic element 44. The elastic element 44 is preferably connected to the connecting region 54 of the second piston region 48 by form fit and / or friction. In particular, the elastic element 44 is pressed onto the connecting region 54 of the second piston region 48. In particular, the elastic element 44 is pressed onto the connecting region 54 of the second piston region 48 by a press fit of at least one, two or more lower spring windings. The connecting region 54 preferably has a substantially constant outer diameter. The connecting region 54 adjoins a region with a larger diameter than the connecting region in the direction of the first piston region 46, which forms an axial bearing surface for the elastic element 44. In particular, the second piston region 48 has a circumferential groove 56 that opens toward the first piston region 46. The piston ring 52 is preferably arranged in the groove 56. The axial length of the piston ring 52 is preferably smaller than the axial length of the groove 56, so that the piston ring 52 can be axially movable relative to the first and second piston areas 46, 48. The first and second piston areas 46, 48 are preferably immovable relative to each other. The movement of the piston ring 52 is preferably limited by the first piston area 46 in the compression direction D and by the second piston area 48 in the rebound direction Z. The movement of the piston rod 20 in the compression direction D preferably drives the auxiliary piston 30 to move together with the piston rod 20 in the compression direction D. When the piston rod 20 moves in the rebound direction Z, the auxiliary piston 30 also moves in the rebound direction Z and enters the rebound stop receptacle 40 after exceeding a certain Z-direction deflection. The piston ring 52 preferably has an outer diameter that corresponds to the inner diameter of the rebound stop receptacle 40, so that the auxiliary piston 30 rests at least partially or completely on the rebound stop receptacle 40 in a fluid-tight manner. When the auxiliary piston 30 enters the rebound stop receptacle 40 , its movement is damped, so that the movement of the auxiliary piston 30 relative to the piston rod 20 in the rebound direction Z is slowed down and the elastic element 44 is preferably compressed.

[0051] The auxiliary piston 30 is preferably dimensioned so that the auxiliary piston 30 closes the rebound stop chamber 32 in a fluid-tight manner when the piston rod 20 moves in the rebound direction Z. For example, the damping cylinder 14 has a constant inner diameter, and the rebound stop receptacle 40 is located in the end region on the side close to the piston rod and abuts against this inner diameter. For example, the rebound stop receptacle 40 has an end region remote from the piston rod and an end region close to the piston rod, wherein the end region remote from the piston rod has, for example, a conically tapering inlet region toward the bottom valve 38, so that the outer diameter of the rebound stop chamber 32 preferably increases gradually from the inner diameter of the damping cylinder 14 to the first inner diameter of the rebound stop receptacle 40, preferably changes continuously. The conical inlet region of the rebound stop receptacle 40 preferably adjoins a region with a constant inner diameter.

[0052] The rebound stop receiving portion 40 is preferably abutted against the closing component 34 by a side end region of the closing component, and preferably forms a fluid seal. In particular, the rebound stop receiving portion 40 is fixed together with the closing component 34 by form fit, material bonding and / or friction connection.

[0053] In addition, the rebound stop receptacle 40 further has, for example, a plurality of radial protrusions extending in the axial direction, which preferably extend from the inlet region in the axial direction by about 40% to 60% of the length of the rebound stop receptacle 40. These protrusions are preferably designed such that their area gradually decreases in the rebound direction. In the context of this specification, the inner diameter of the rebound stop receptacle 40 refers to the inner diameter without considering the protrusions.

[0054] The outer diameter of the first and second piston areas 46, 48 is preferably designed to be smaller than the inner diameter of the rebound stop receptacle 40 in any case, so that the hydraulic fluid can flow between the first and second piston areas 46, 48 and the rebound stop receptacle. The outer diameter of the piston ring 52 preferably corresponds to the inner diameter of the rebound stop receptacle 40 and forms a fluid seal therewith. In particular, the inner diameter of the piston ring 52 is larger than the inner diameter of the recess 56 of the second piston area 48, so that the hydraulic fluid can flow between the piston ring 52 and the first and / or second piston area 46, 48. The auxiliary piston 30 preferably has a bypass channel 64, which is formed between the inner diameter of the piston ring 52 and the first and / or second piston area 46, 48 and extends in particular along the circumference, preferably covering the entire circumference. The bypass channel 64 forms a fluid connection between the rebound stop chamber 32 and the first working chamber 22 in the compression direction of the auxiliary piston 30.

[0055] The auxiliary piston 30 is preferably designed to enable the piston ring 52 to move from an open position to a closed position. In the open position, the bypass channel 64 is in particular fully open; in the closed position, the flow diameter of the bypass channel 64 is reduced relative to the open position, in particular partially or completely closed by the piston ring 52. Preferably, in the closed position, the bypass channel 64 is formed only by the opening 62 of the piston ring 52 as a C-ring.

[0056] The second piston area 48 has an axial bearing surface 66 for abutting against the piston ring 52 in the closed position. The bearing surface 66 is preferably designed to form a fluid-tight seal with the piston ring 52, in particular over the entire circumference of the piston ring 52. For example, the bearing surface 66 is designed as a flat surface or has a contour corresponding to the surface contour of the piston ring 52, thereby forming a fluid-tight connection.

[0057] The first piston area 46 has an axial bearing surface 68 for contacting the piston ring 52 in the open position. The bearing surface 68 is preferably designed so that when the piston ring 52 abuts against the bearing surface 68, the hydraulic fluid can flow through the bypass channel 64, in particular between the bearing surface 68 and the piston ring 52. The bearing surface 68 preferably has a contour structure, in particular a plurality of grooves 70 and protrusions 72. For example, the grooves 70 are formed on the outer circumference of the first piston area 46 and form an axial flow channel in the direction from the working chamber 22 on the piston rod side to the rebound stop chamber 32.

[0058] The auxiliary piston 30 is preferably designed such that, when it moves in the rebound direction Z, the piston ring 52 bears against the second piston region 48, in particular against the axial bearing surface 66, in a fluid-tight manner. When the auxiliary piston 30 moves in the rebound stop receptacle 40, the piston ring 52 also bears against the inner wall of the rebound stop receptacle 40 in a fluid-tight manner, so that the hydraulic fluid can only flow through the opening 62 of the piston ring 52, which is formed as a C-ring. The auxiliary piston 30 is preferably designed such that, when it moves in the rebound stop receptacle 40 in the compression direction D, the piston ring 52 bears against the first piston region 46, in particular against the axial bearing surface 68, and the hydraulic fluid can flow between the contour of the bearing surface 68 and the piston ring 52, as well as through the bypass channel 64.

[0059] For example, the first piston region 46 has a mounting region 60 for mounting the first piston region 46 on the second piston region 48. The mounting region 60 preferably forms the end of the first piston region 46 facing the second piston region 48. In particular, the mounting region 60 has a plurality of at least partially radially inwardly directed connecting projections 74, which preferably point to the piston rod 20 at an angle of about 10° to 60°, more preferably 20° to 40°, in particular 30° relative to the axial direction. For example, the second piston region 48 has a cutout 50, in particular an annular groove, for accommodating the connecting projection 74. The connecting projection 74 preferably forms a snap connection with the cutout of the second piston region 48. For example, the mounting region 60 has a profile structure, which is provided with a plurality of projections on an outwardly directed circumferential surface, which are, for example, evenly distributed with respect to each other, in particular extending in the axial direction. The second piston region 48 also has an axial bearing surface 78, which faces the elastic element 44 and against which the elastic element 44 rests. The bearing surface 78 is, for example, in the form of a flat surface.

[0060] For example, the rebound stop 28 has a sealing ring 76 which is arranged around the circumference of the piston rod 20 and coaxially therewith. The sealing ring 76 preferably abuts the piston rod 20 so that it can slide in the axial direction. In particular, the sealing ring 76 is arranged between the auxiliary piston 30 and the piston rod 20. For example, the sealing ring 76 is arranged between the first piston area 46 and the second piston area 48. In particular, the sealing ring 76 abuts against the inner surface of the second piston area 48, preferably between the piston rod 20 and the second piston area 48, and for example radially at a certain distance from the second piston area 48. The inner surface of the second piston area 48 preferably has a radially inward projection, which forms an axial stop surface for the sealing ring 76, so that the sealing ring 76 is in fluid-tight contact with the stop surface of the second piston area 48. The sealing ring 76 also abuts in particular against the first piston area 46, preferably against the end face of the first piston area 46. The sealing ring 76 preferably abuts against the mounting area 60 of the first piston area 46 in a fluid-tight manner. In particular, the sealing ring 76 bears against at least the piston rod 20 , the first piston region 46 and the second piston region 48 in a fluid-tight manner.

[0061] List of Reference Numerals

[0062] 10 Shock absorber

[0063] 12 Outer tube

[0064] 14 vibration damping cylinder / inner tube

[0065] 16 Balance chamber

[0066] 18 Working piston

[0067] 20 Piston rod

[0068] 22 First working chamber

[0069] 24 Second working chamber

[0070] 26 Seals

[0071] 28 Rebound stop

[0072] 30 Auxiliary piston

[0073] 32 Rebound stop chamber

[0074] 34 Closure components

[0075] 36 Base

[0076] 38 Foot valve

[0077] 40 Rebound stop receiving portion

[0078] 42 seats

[0079] 44 Elastic element

[0080] 46 First Piston Area

[0081] 48 Second Piston Zone

[0082] 50 slots

[0083] 52 Piston ring

[0084] 54 Connection area

[0085] 56 grooves

[0086] 60 Installation area

[0087] 62 Opening

[0088] 64 Bypass channel

[0089] 66 Axial bearing surface of the first piston area

[0090] 68 Axial bearing surface of the second piston area

[0091] 70 Notch

[0092] 72 bulge

[0093] 74 Connection protrusion

[0094] 76 Sealing ring

[0095] 78 Support surface

[0096] Z springback direction

[0097] D Compression direction

Claims

1. A shock absorber (10) for a vehicle, comprising: - a damping cylinder (14) filled with hydraulic fluid, - a working piston (18) connected to a piston rod (20) and arranged in the damping cylinder (14) so ​​as to be movable forward and backward, wherein the interior of the damping cylinder (14) is divided into a first working chamber (22) and a second working chamber (24) by the working piston (18), - A rebound stop (28) having: - an auxiliary piston (30) which concentrically surrounds the piston rod (20), and a sleeve-shaped rebound stop receptacle (40) mounted on the damping cylinder (14) for receiving the auxiliary piston (30) during the rebound phase, -characterized in that - the auxiliary piston (30) is mounted on the piston rod (20) and is axially movable relative to the piston rod (20), and The rebound stop (28) has an elastic element (44) which is fastened to the auxiliary piston (30).

2. The shock absorber (10) according to claim 1, wherein one end of the elastic element (44) is mounted on the auxiliary piston (30), and the other end of the elastic element is mounted through a seat (42) so as to be connected in a fixed position relative to the piston rod (20).

3. The shock absorber (10) according to any of the preceding claims, wherein the rebound stop device (28) comprises a sealing ring (76) between the auxiliary piston (30) and the piston rod (20), the sealing ring being arranged to provide a fluid seal of the auxiliary piston (30) relative to the piston rod (20).

4. The shock absorber (10) according to claim 3, wherein the sealing ring (76) is mounted so as to be axially movable relative to the piston rod (20).

5. The shock absorber (10) according to any one of claims 3 and 4, wherein the sealing ring (76) is mounted on the auxiliary piston (30) so as to be connected in a fixed position relative to the auxiliary piston (30).

6. The shock absorber (10) according to any one of claims 3 to 5, wherein the auxiliary piston (30) has a first piston area (46) and a second piston area (48), and the sealing ring (76) abuts against the first and second piston areas (46, 48) in a fluid-tight manner.

7. The shock absorber (10) according to any one of the preceding claims, wherein the auxiliary piston (30) has a first piston area (46) and a second piston area (48), and a piston ring (52) is arranged between the first and second piston areas (46, 48), and the piston ring (52) is mounted to be axially movable relative to the first and second piston areas (46, 48).

8. The shock absorber (10) according to any one of claims 6 and 7, wherein the first and second piston areas (46, 48) are connected to each other by an interlocking connection, a friction connection and / or a substance-to-substance adhesive connection.

9. A shock absorber (10) according to any one of claims 6 to 8, wherein the first piston area (46) has a mounting area (60) for mounting the first piston area (46) on the second piston area (48), and wherein the mounting area (60) has a plurality of at least partially radially inward connecting protrusions (74) that interact with cutouts in the second piston area (48) to form an interlocking and / or friction connection, in particular a latching connection.

10. A shock absorber (10) according to any of the preceding claims, wherein the rebound stop device (28) comprises a rebound stop chamber (32), which is formed between a rebound stop receptacle (40), an auxiliary piston (30) and a closing component (34) of a fluid-tight damping cylinder (14) on the piston rod side, and the rebound stop chamber is only fluidically connected to the first working chamber (22).

11. The shock absorber (10) according to claim 1, wherein the elastic element (44) is arranged at least partially in a rebound stop receptacle (40).

12. A shock absorber (10) according to any of the preceding claims, wherein the auxiliary piston (30) has a connection area (54) for connecting the auxiliary piston (30) to the elastic element (44), and wherein the elastic element (44) is connected to the connection area (54) of the auxiliary piston (30) by an interlocking and / or friction connection, in particular a press-fit connection.

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