Vibration damper for a motor vehicle

Abstract

The present invention relates to a vibration damper (10) for a vehicle, comprising: a damper tube (14) filled with hydraulic fluid, a working piston (18) connected to a piston rod (20) and arranged to be movable back and forth within the damper tube (14), wherein the interior of the damper tube (14) is divided by the working piston (18) into a first working chamber (22) on the piston rod side and a second working chamber (24) further away from the piston rod, an auxiliary piston (50) attached to the piston rod (20), and a pressure stop arrangement (48) with a pressure stop receptacle (68) provided within the damper tube (14) for receiving the auxiliary piston (50) in the compression stage, wherein the pressure stop receptacle (68) comprises a sleeve-shaped area (64) with a constant diameter and has at least one expansion (52) projecting radially from the sleeve-shaped area (64).

Description

[0001] The invention relates to a vibration damper for a motor vehicle with a pressure stop arrangement.

[0002] From DE 10 2015 121 140 A1, a hydraulic vibration damper with a hydraulic pressure stop is known. A hydraulic pressure stop typically serves to provide additional damping in the compression stage of the vibration damper. In known vibration dampers, an additional piston moves into a pressure stop chamber, thus generating additional damping when the piston rod moves in the compression direction. The components interacting in the pressure damping process must typically adhere to very precise manufacturing tolerances in order to compensate for, for example, lateral forces on the piston rod. Manufacturing these components is therefore usually very expensive. Furthermore, the installation space for a pressure stop within the vibration damper is limited.

[0003] Starting from this premise, the object of the present invention is to provide a vibration damper with a pressure stop arrangement that is cost-effective to manufacture and easy to assemble.

[0004] This problem is solved according to the invention by a vibration damper having the features of independent device claim 1. Advantageous embodiments are described in the dependent claims.

[0005] A vibration damper for a vehicle comprises, according to a first aspect, a damper tube filled with hydraulic fluid, a working piston connected to a piston rod and arranged to be movable back and forth within the damper tube, wherein the interior of the damper tube is divided by the working piston into a first working chamber on the piston rod side and a second working chamber further away from the piston rod. The vibration damper preferably also includes a sealing assembly that provides a fluid-tight seal for the damper tube on the piston rod side.Furthermore, the vibration damper comprises an additional piston attached to the piston rod and a pressure stop assembly with a pressure stop receptacle located inside the damper tube for receiving the additional piston in the compression stage. The pressure stop receptacle comprises a sleeve-shaped section with a constant diameter, preferably an inner diameter, and has at least one expansion projecting radially from the sleeve-shaped section. Such a sleeve-shaped section with a constant diameter allows for simple manufacturing of the pressure stop receptacle. In particular, the pressure stop receptacle is manufactured by cold extrusion. Thus, no machining is necessary, which makes the manufacturing of the pressure stop receptacle significantly more cost-effective. Preferably, the pressure stop receptacle is made of a steel such as DD13.

[0006] The vibration damper is, for example, a single-tube or a multi-tube vibration damper. For instance, a multi-tube vibration damper for a vehicle comprises an outer tube and an inner tube arranged coaxially to it, wherein a compensating chamber for receiving hydraulic fluid is formed between the outer tube and the inner tube, and a working piston connected to a piston rod, which is arranged to move back and forth within the inner tube. The interior of the inner tube is divided by the working piston into a first working chamber on the piston rod side and a second working chamber furthest from the piston rod. The compensating chamber is preferably at least partially filled with a gas, particularly at its upper end. The outer tube preferably forms at least part of the housing of the vibration damper. The inner surface of the inner tube is preferably designed as a guide for the working piston.The working piston preferably has a valve assembly connecting the first and second working chambers. In a monotube vibration damper, an outer tube is preferably not provided. The inner tube is referred to as the damper tube and, as described above with reference to the inner tube, accommodates the piston rod and the working piston.

[0007] In a multi-tube vibration damper, the damper has, in particular, a sealing assembly designed and arranged to fluidically seal the interior of the outer tube on the piston rod side. The piston rod end of the inner tube is preferably attached to the sealing assembly. Opposite the sealing assembly, at the end furthest from the piston rod, the compensation chamber and the second working chamber are preferably fluidically sealed by means of a bottom piece. The compensation chamber is preferably fluidically connected to the first or second working chamber via openings in the inner tube. For example, the compensation chamber is sealed to the inner tube by means of a bottom element. A bottom valve is particularly arranged on the bottom element, which is preferably attached to the end of the inner tube furthest from the piston rod. The second working chamber is preferably fluidly connected to the compensation chamber via the bottom valve.The bottom valve is preferably a check valve that allows flow in both directions or only in one direction. For example, the bottom valve is designed as a check valve in the pull direction (outwards from the inner tube when the piston moves) and as a characteristic-generating valve in the push direction (inwards from the inner tube when the piston moves).

[0008] In a monotube vibration damper, the damper particularly features a sealing assembly designed and arranged to fluidically seal the interior of the damper tube on the piston rod side. The piston rod end of the damper tube is preferably attached to the sealing assembly. The sealing assembly is preferably arranged coaxially with the piston rod and surrounds it circumferentially. Opposite the sealing assembly, at the end furthest from the piston rod, the interior of the damper tube is preferably fluidically sealed by means of an axially movable sealing element. The sealing element preferably separates a gas chamber adjoining it in the axial direction from the working chamber filled with hydraulic fluid.

[0009] In the following description, the term vibration damper refers to both a multi-tube vibration damper and a single-tube vibration damper, where the damper tube is the inner tube of a multi-tube vibration damper.

[0010] The pressure stop arrangement is preferably arranged inside the damper tube, in particular in the end region of the damper tube furthest from the piston rod, and preferably includes the pressure stop receptacle.

[0011] The auxiliary piston preferably comprises a piston ring that is axially movable within the auxiliary piston and preferably has its outer circumferential surface in at least partial or complete fluid-tight contact with the inner wall of the pressure stop receptacle. The piston ring is preferably not fixed to the piston rod or the auxiliary piston. The piston ring and piston rod are, in particular, mounted so as to be movable relative to each other. The pressure stop assembly also includes a pressure stage working chamber, which is separated by the piston ring within the damper tube, especially the pressure stop receptacle. The auxiliary piston is fixed to the piston rod and arranged in the pressure direction relative to the working piston.The piston ring is, for example, circular, cylindrical or, in particular, c-shaped and has, for example, a through-opening designed as a slot, which represents a complete circumferential interruption of the annular piston ring.

[0012] The pressure stop arrangement preferably has a pressure stage working chamber separated by the piston ring within the pressure stop receptacle, wherein the interruption or passage opening at least partially or completely forms a bypass channel between the pressure stage working chamber and the working chamber remote from the piston rod. The pressure stage working chamber is preferably formed between the piston ring and the base of the pressure stop receptacle, which is particularly hollow cylindrical. The bypass channel is preferably formed by the interruption or passage opening in the piston ring and the space between the outer diameter of the auxiliary piston and the inner diameter of the pressure stop receptacle.

[0013] In the following, a movement in the direction of tension is understood to mean a movement in the direction of the locking package in the piston rod-side area of ​​the shock absorber, and a movement in the direction of compression is understood to mean a movement in the direction of the bottom valve in the area of ​​the shock absorber furthest from the piston rod.

[0014] In the compression stage, the piston rod moves in the compression direction, causing the piston ring to move within the compression stop chamber in the same direction. The bypass channel allows hydraulic fluid to flow from the compression stage working chamber when the piston ring moves in the compression direction, thus damping the piston rod movement in that direction.

[0015] According to a first embodiment, the expansion extends from the piston-rod-side end of the pressure stop receptacle in an axial direction, particularly in the pressure direction. Preferably, the expansion extends to the end face of the pressure stop receptacle. The expansion preferably forms a bypass path extending from the end face of the pressure stop receptacle between the wall of the pressure stop receptacle and the auxiliary piston. This bypass path allows fluid to flow from the pressure stage working chamber to the working chamber furthest from the piston rod.

[0016] According to a further embodiment, the sleeve-shaped section has a constant diameter over the entire axial extent of the pressure stop receptacle, with the exception of the at least one expansion. Such a pressure stop receptacle is particularly easy to manufacture. Preferably, the pressure stop receptacle consists of the sleeve-shaped section, the at least one expansion, and a base. The pressure stop receptacle is particularly well-made in one piece.

[0017] According to another embodiment, the pressure stop receptacle has a plurality of expansions that are arranged at uniform intervals in the circumferential direction. For example, the pressure stop receptacle has at least two, three, four, or five expansions.

[0018] According to a further embodiment, the expansion has a first region located at the piston-rod end of the pressure stop receptacle and having a constant diameter along its axial extent. The diameter of the first region of the expansion of the pressure stop receptacle is preferably larger than the diameter of the sleeve-shaped region of the pressure stop receptacle. The first region preferably forms the piston-rod end of the expansion.

[0019] According to a further embodiment, the pressure stop receptacle is attached to the damper tube at the first section. Preferably, the pressure stop receptacle is fastened to the damper tube by means of the first section via a force-fit, form-fit, or material-fit connection. In particular, the pressure stop receptacle is attached to the damper tube exclusively at the first section. Preferably, the pressure stop receptacle is welded to the inner tube.

[0020] According to a further embodiment, the first region has a constant circumferential width over its axial extent. The circumferential width is understood to mean the extent in the circumferential direction, in particular a partial circular segment.

[0021] According to a further embodiment, the expansion has a second region that adjoins the first region directly in the axial direction and has a diameter that changes along its axial extent. Preferably, the diameter of the second region is decreased or increased in the axial direction. A changing diameter causes a change in the bypass path and thus in the damping in the compression stage. Preferably, the diameter decreases in the compression direction. Optionally, the diameter of the second region is constant.

[0022] According to another embodiment, the diameter of the second region decreases constantly in the axial direction, particularly in the compression direction. A stepwise change is also conceivable. A reduction in the compression direction results in progressive damping in the compression stage.

[0023] According to a further embodiment, the second region has a circumferential width that changes along its axial extent. According to another embodiment, the circumferential width of the second region preferably decreases constantly in the pressure direction. This also ensures progressive damping of the movement of the additional piston in the pressure stage.

[0024] According to a further embodiment, the pressure stop receptacle has a plurality of expansions, all of which are identical. According to a further embodiment, the expansion extends over approximately half the axial extent of the pressure stop receptacle. This achieves progressive damping of the piston movement up to approximately half the immersion depth of the piston in the pressure stop receptacle. Preferably, the expansions are arranged exclusively in the piston rod-side half of the pressure stop receptacle.

[0025] According to another embodiment, the pressure stop receptacle has a wall that has no bores or openings through which hydraulic fluid can flow through the wall in a radial direction.

[0026] An annular space, through which the hydraulic fluid can flow, is formed between the pressure stop receptacle and the damper tube. This annular space preferably forms a fluid connection between the working chamber furthest from the piston rod and the bottom valve, bypassing the pressure stop receptacle. In normal operation, when the auxiliary piston is not in the pressure stop receptacle, the receptacle does not present a flow obstruction and has a negligible effect on the vibration damper's behavior. Even when the auxiliary piston is inside the pressure stop receptacle, the receptacle does not present a flow obstruction, thus allowing flow to the bottom valve.

[0027] The pressure stop receptacle is preferably hollow cylindrical. The piston ring is preferably made of a plastic. Preferably, the piston ring is manufactured by injection molding. Manufacturing the piston ring from a plastic offers a cost-effective manufacturing process.

[0028] The auxiliary piston preferably comprises a valve body with at least one or more axial through-bores, which are at least partially or completely covered by valve discs on the piston rod side. The valve discs are preferably pre-tensioned such that they allow flow from the pressure stage working chamber through the through-bores into the second working chamber above a certain pressure in the pressure stage working chamber. The through-bores, together with the valve discs, thus prevent a pressure increase in the pressure stage working chamber exceeding a certain value. In addition to the through-bores, a bypass channel is provided, offering an additional flow channel when the auxiliary piston moves in the pressure direction. The bypass channel is formed, in particular, between the valve body and the pressure stop receptacle, as well as by the interruption in the piston ring.

[0029] The valve body and the valve discs are preferably connected by a connecting element, such as a screw or rivet, for example with a washer. The piston ring is preferably arranged around the valve body such that it is axially, and in particular continuously, movable from a first position, in which it rests against a shoulder of the valve body, to a second position, in which it rests against a disc attached to the end face of the valve body. The valve body optionally has recesses on its outer surface, which are preferably aligned with cutouts in the disc, so that a bypass channel is formed between the pressure stage working chamber and the working chamber furthest from the piston rod. Optionally, the valve body has no recess, so that the bypass channel is formed exclusively by the through-hole in the piston ring.

[0030] When the piston rod moves in the compression direction, the auxiliary piston is moved into the pressure stop recess. During compression, the piston ring rests against the shoulder of the valve body, at least partially closing the bypass channel. When the auxiliary piston moves in the extension direction, the piston ring rests against the disc, preferably opening the bypass channel. The piston ring preferably serves as a throttling element to restrict the flow cross-section of the bypass channel. Description of the drawings

[0031] The invention is explained in more detail below with reference to several exemplary embodiments and the accompanying figures. Fig. Figure 1 shows a schematic representation of a section of a vibration damper in a longitudinal sectional view according to an exemplary embodiment. Fig. Figure 2 shows a schematic representation of a pressure stop mounting in a longitudinal section view according to an exemplary embodiment. Fig. Figure 3 shows a schematic representation of a pressure stop in a further longitudinal section view according to an exemplary embodiment. Fig. Figure 4 shows a schematic representation of a pressure stop recording in a perspective view according to an exemplary embodiment.

[0032] Fig. Figure 1 shows a vibration damper 10, which is, by way of example, a multi-tube vibration damper, specifically a two-tube vibration damper. The vibration damper 10 has an outer tube 12, which forms an outer surface, in particular a housing, of the vibration damper 10. Inside the outer tube 12, a damper tube 14, also referred to as an inner tube 14, is arranged coaxially to it. A compensation chamber 16 is formed between the outer tube 12 and the inner tube 14, which is preferably at least partially or completely filled with a hydraulic fluid. For example, the compensation chamber 16 is partially filled with a gas.

[0033] Within the inner tube 14, a working piston 18, connected to a piston rod 20, is arranged such that it is movable within the inner tube 14, the inner tube 14 preferably serving as a guide for the working piston 18. The working piston 18 preferably has a valve assembly. For example, the valve assembly comprises a rebound valve for damping the piston movement during the rebound stage and a compression valve for damping the piston movement during the compression stage. Preferably, the valves are each formed by a through-hole 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, located towards the piston rod, and a second working chamber 24, located further away from the piston rod. The end of the piston rod 20 protruding from the damper tube 14 is preferably connectable to the vehicle body.The working piston 18 is preferably fixedly attached to the piston rod. The vibration damper 10 comprises an additional piston 50 which is also fixedly attached to the piston rod 20, the additional piston 50 being attached to a section of the piston rod 20 adjoining the working piston in the pressure direction D. Preferably, the additional piston 50 is attached to the end of the piston rod 20 located inside the damper tube 14. An exemplary reinforcement, particularly a sleeve-shaped one, is provided between the working piston 18 and the additional piston 50, which is arranged coaxially around the piston rod 20 and attached to the piston rod 20.

[0034] The interior of the outer tube 12 is preferably fluidically sealed on the piston rod side by means of a sealing assembly (not shown). Opposite the sealing assembly, at the end furthest from the piston rod, the compensation chamber 16 is preferably fluidly sealed by means of a bottom piece 36. The interior of the damper tube 14, in particular the second working chamber 24, is preferably also fluidly sealed by means of the bottom piece 36. It is also conceivable that a further bottom element is provided separately from the bottom piece, which seals the outer tube 12. An exemplary bottom valve 38 is arranged on the bottom piece 36, which is preferably attached to the end of the inner tube 14 furthest from the piston rod. The bottom valve 38 is preferably a check valve that allows 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 bottom valve 38. The piston rod end of the inner tube 14 is preferably attached to the closure assembly.

[0035] The outer tube 12 is preferably cylindrical and optionally has a smaller diameter at the piston rod end. The outer tube 12 is, by way of example, fluidically sealed to the piston rod 20 by a seal attached to the piston rod end of the outer tube 14.

[0036] The vibration damper 10 includes, by way of example, a pressure stop arrangement 48, which is arranged inside the damper tube 14, in particular in the end region of the damper tube 14 furthest from the piston rod. The pressure stop arrangement 48 preferably includes a pressure stop receptacle 68, which is arranged inside the inner tube 14 and is essentially hollow cylindrical. Preferably, the pressure stop receptacle 68 bears at least partially against the inner surface of the inner tube 14.

[0037] The auxiliary piston 50 includes, for example, a piston ring 30, which is axially movable within the auxiliary piston 50 and preferably bears at least partially or completely against the inner wall of the pressure stop receptacle 68 in a fluid-tight manner with its outer circumferential surface. Preferably, the piston ring 30 is axially movable within the auxiliary piston 50 such that the pressure stop receptacle 68 forms a guide for the piston ring 30. The piston ring 30, in particular, separates a pressure stage working chamber 56 within the pressure stop receptacle 68. The pressure stage working chamber 56 is preferably arranged entirely behind the piston ring 30 in the pressure direction D, within the pressure stop receptacle 68. Preferably, the pressure stop receptacle 68 bears partially against the inner wall of the damper tube 14 with its outer diameter.

[0038] The pressure stop receptacle 68 has, by way of example, a connection area 32 at its end region facing the working piston 18, which is preferably fixedly connected to the inner tube 14. In particular, the connection area 32 of the pressure stop receptacle 68 has a larger outer diameter than the remaining region of the pressure stop receptacle 68, which extends, in particular, from the connection area in the pressure direction D. Outside the connection area, the pressure stop receptacle 68 preferably has an outer diameter that is smaller than the inner diameter of the damper tube 14, so that the hydraulic fluid can flow between the damper tube 14 and the pressure stop receptacle 68. Preferably, the pressure stop receptacle 68 is positively locked, materially locked, and / or force-locked to the inner tube 14.

[0039] The auxiliary piston 50 comprises a valve body 58 with at least one or a plurality of axial through-bores 60, which are covered by valve discs 62. The valve discs 62 are attached to the piston rod end of the valve body 58 and are pre-tensioned such that they allow flow from the pressure stage working chamber 56 through the through-bores 60 into the second working chamber 24 above a certain pressure in the pressure stage working chamber 56. The through-bores 60 together with the valve discs 62 thus prevent a pressure increase in the pressure stage working chamber 56 exceeding a certain value.

[0040] The piston ring 30 is arranged circumferentially around the valve body 58 and is particularly axially movable. The piston ring 30 is, for example, annular, cylindrical, or, in particular, C-shaped and has, for example, a slotted opening that completely interrupts the circumferential circumference of the annular piston ring 30. Preferably, the piston ring has a plurality of openings, which are, in particular, formed as recesses in the inner wall and / or the piston rod-side end face of the piston ring 30. The valve body 58 has, for example, a radially outwardly projecting shoulder at its piston rod-side end, which forms an axial contact surface for the piston ring 30. The piston ring 30 is preferably designed such that it forms a fluid-tight seal with the inner wall of the damper tube 14.The piston ring 30 has, for example, a through-hole through which hydraulic fluid can flow. The auxiliary piston 50 preferably has a disk 34, which is arranged at the end of the auxiliary piston 50 furthest from the piston rod, in particular at the end of the valve body 58. The disk 34 preferably projects radially beyond the valve body 58 and forms an axial contact surface for the piston ring 30. The valve body 58, the valve disks 62, and the disk 34 are preferably connected by a connecting element, such as a screw or a rivet, for example with a washer.

[0041] The piston ring 30 is preferably arranged around the valve body 58 such that it is axially, and in particular continuously, movable from a first position, in which it rests against the shoulder of the valve body 58, to a second position, in which it rests against the disk 34. The valve body 58 optionally has recesses on its outer surface, which are preferably aligned with cutouts in the disk 34, so that a bypass channel is formed between the pressure stage working chamber 56 and the working chamber 24 furthest from the piston rod. Optionally, the valve body 58 has no recess, so that the bypass channel is formed exclusively by the through-hole in the piston ring 30.

[0042] During operation of the shock absorber 10 and when the piston rod 20 moves in the compression direction D, the auxiliary piston 50 is moved into the pressure stop receptacle 68, particularly in the compression direction D towards the bottom of the pressure stop receptacle 68. When the auxiliary piston 50 moves in the compression direction D, the piston ring 30 rests against the shoulder of the valve body 58 and at least partially closes the bypass channel. When the auxiliary piston 50 moves in the extension direction Z, the piston ring 30 rests against the disk 34 and preferably opens the bypass channel. The piston ring 30 preferably serves as a throttling element to restrict the flow cross-section of the bypass channel.

[0043] Fig. 2, Fig. 3 to Fig.Figure 4 shows the pressure stop receptacle 68 in different sectional views and in a perspective view. The pressure stop receptacle 68 is, by way of example, cylindrical and has a wall 70. By way of example, the wall 70 of the pressure stop receptacle 68 has no bores or openings through which hydraulic fluid can flow. The pressure stop receptacle 68 preferably has a plurality of expansions 52 formed in the wall 70. Preferably, the pressure stop receptacle 68 comprises a cylindrical region 64 having a constant diameter. The expansions 52 are preferably diameter enlargements of the pressure stop receptacle 68 and project, in particular, radially from the cylindrical region 64.

[0044] By way of example, the pressure stop receptacle 68 has five expansions 52. The majority of expansions 52 are preferably arranged at uniform intervals in the circumferential direction. The expansions 52 preferably each have a first region 32, which is arranged at the piston rod-side end of the pressure stop receptacle 68 and, in particular, has a diameter that is constant over the axial extent of the first region. Preferably, the first region 32 is designed as a fastening area that is firmly connected to the inner wall of the damper tube 14. In particular, the pressure stop receptacle 68 is connected to the damper tube 14 via the first region 32 by a material-fit, positive-fit, or force-fit connection. The first region 32 preferably has a circumferential width that is constant over the axial extent.

[0045] The expansions 52 each preferably have a second region 66 that extends directly to the first region 32 in the axial direction, particularly in the direction furthest from the piston rod. The second region 66 has a diameter that changes along its axial extent. Specifically, the diameter of the second region 66 decreases in the axial direction, particularly towards the base 36 or in the pressure direction D. Preferably, the diameter decreases constantly in the axial direction. The second region 66 preferably has a circumferential width that changes along its axial extent. Preferably, the circumferential width decreases in the axial direction, particularly towards the base 36 or in the pressure direction D.

[0046] The expansions 52 extend, for example, over approximately half the axial extent of the pressure stop receptacle 68. Preferably, the expansions 52 are all identical. The lower half of the pressure stop receptacle 68, pointing towards the base piece 36, is preferably completely hollow cylindrical with a constant diameter in the axial direction and, in particular, comprises the cylinder base. The expansions 52 preferably extend axially from the piston rod end, especially the end face. In particular, the pressure stop receptacle 68 consists of the expansions 52, the sleeve-shaped section 64, and the base 72.

[0047] The expansions 52 preferably form a bypass path between the wall 70 of the pressure stop receptacle 68 and the auxiliary piston 50. For example, the bypass path is tapered in the pressure direction, so that the flow cross-section of the bypass path decreases in the pressure direction. The inner wall of the damper tube 14 and the outer wall of the pressure stop receptacle 68 are preferably spaced apart from each other. Preferably, the sleeve-shaped section 64 is spaced apart from the damper tube 14, so that hydraulic fluid can flow between the damper tube 14 and the sleeve-shaped section 64 of the pressure stop receptacle 68. Reference symbol list 10 vibration dampers 12 Outer pipe 14 Damper tube / inner tube 16 compensation area 18 working pistons 20 piston rod 22 first workroom 24 second workroom 30 piston rings 32 Connection area 34 discs 36 bottom piece 38 Bottom valve 48 Pressure stop arrangement 50 additional pistons 52 expansions 56 pressure stage working space 58 valve bodies 60 through holes 62 valve discs 64 cylindrical area 66 second area 68 Pressure stop holder 70 Wall of the pressure stop mount 72 Floor Z direction of travel D Pressure direction QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2015 121 140 A1

[0002]

Claims

[1] Vibration damper (10), for a vehicle, comprising: - a damper tube filled with hydraulic fluid (14), - a working piston (18) connected to a piston rod (20), which is arranged to be movable back and forth inside the damper tube (14), wherein the interior of the damper tube (14) is divided by the working piston (18) into a first working chamber (22) on the piston rod side and a second working chamber (24) farther from the piston rod, - an additional piston (50) which is attached to the piston rod (20) and - a pressure stop arrangement (48) with a pressure stop receptacle (68) located inside the damper tube (14) for receiving the additional piston (50) in the compression stage, characterized by , that the pressure stop receptacle (68) comprises a sleeve-shaped area (64) with a constant diameter and has at least one expansion (52) that protrudes radially from the sleeve-shaped area (64). [2] Vibration damper (10) according to claim 1, wherein the widening extends from the piston rod side end of the pressure stop receptacle (68) in the axial direction. [3] Vibration damper (10) according to one of the preceding claims, wherein the sleeve-shaped area (64) has a constant diameter over the entire axial extent of the pressure stop receptacle (68), except for the at least one expansion (52). [4] Vibration damper (10) according to one of the preceding claims, wherein the pressure stop receptacle (68) has a plurality of expansions (52) which are arranged uniformly spaced apart from each other in the circumferential direction. [5] Vibration damper (10) according to one of the preceding claims, wherein the expansion (52) has a first region (32) which is arranged at the piston rod side end of the pressure stop receptacle (68) and has a diameter constant over the axial extent of the first region (32). [6] Vibration damper (10) according to claim 5, wherein the pressure stop receptacle (68) is attached to the damper tube (14) via the first area (32). [7] Vibration damper (10) according to claim 5 or 6, wherein the first region (32) has a circumferential width that is constant over the axial extent. [8] Vibration damper (10) according to one of claims 5 to 7, wherein the expansion (52) has a second area (66) which is directly connected to the first area (32) in the axial direction and has a diameter that changes over the axial extent of the second area (66). [9] Vibration damper (10) according to claim 8, wherein the diameter of the second region (66) decreases constantly in the axial direction. [10] Vibration damper (10) according to one of claims 8 or 9, wherein the second region (66) has a circumferential width that changes over the axial extent. [11] Vibration damper (10) according to one of claims 8 to 10, wherein the circumferential width of the second region (66) decreases constantly in the pressure direction (D). [12] Vibration damper (10) according to one of the preceding claims, wherein the pressure stop receptacle (68) has a plurality of expansions (52) which are all identically designed. [13] Vibration damper (10) according to one of the preceding claims, wherein the widening (52) extends over about half of the axial extent of the pressure stop receptacle (68). [14] Vibration damper (10) according to one of the preceding claims, wherein the pressure stop receptacle (68) has a wall (70) and wherein the widening (52) forms a bypass path between the wall (70) of the pressure stop receptacle (68) and the additional piston (50). [15] Vibration damper (10) according to one of the preceding claims, wherein the pressure stop receptacle (68) has a wall (70) which has no bores or openings through which hydraulic fluid can flow through the wall (70) in a radial direction.

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