Pressure stop buffer for a vibration damper

Abstract

vibration damper (2) comprising - a damper tube at least partially filled with damping fluid, in which a piston rod is movable back and forth, wherein a working piston is movable along with the piston rod, by which the interior of the damper tube is divided into a working space on the piston rod side and a working space away from the piston rod, - at least one pressure stop buffer (1), wherein the at least one pressure stop buffer (1) comprises an outer contour (4) for at least partial inclusion in a dome bearing housing (3) and a hollow cylindrical basic structure with an inner contour (6) for coaxial arrangement on a piston rod (5) of the vibration damper (2), characterized by the fact that the outer contour (4) of the pressure stop buffer (1) has at least in an area relating to the at least partial reception in the strut bearing housing (3) a three-dimensionally structured surface (7) with several protrusions (8, 8', 8'', 8''') and / or several depressions (9, 9', 9'', 9'''), wherein the multiple protrusions (8, 8', 8'', 8''') and / or depressions (9, 9', 9'', 9''') are at least partially homogeneously distributed, at least in the area of ​​at least partial reception in the strut bearing housing (3), wherein more than 5% of the multiple protrusions (8, 8', 8'', 8''') at least in the area of ​​at least partial reception in the strut bearing housing (3) have a height in the range of 0.2 to 0.3 mm relative to the zero plane of a forming tool with which the pressure stop buffer (1) was manufactured.

Description

[0001] The present invention relates to a vibration damper with a pressure stop buffer. State of the art

[0002] Pressure stop buffers are known in the art in a variety of embodiments. Pressure stop buffers, also referred to as pressure stops, are typically mounted on the piston rod of a vibration damper and serve to limit the compression travel of vibration dampers without generating noise. Noise emission includes, for example, disturbing noises that can be perceived even in the interior of motor vehicles. Often, the noise can be attributed to relative movements between the pressure stop buffer and components of the vibration damper that are in contact with it. In particular, these can be relative movements between the piston rod and the pressure stop buffer mounted on that piston rod.Furthermore, the noise disturbance can also be caused, for example, by relative movements between a strut mount, particularly a strut mount housing, and the pressure stop buffer located within it. The main cause of the noise problem is considered to be the physical effect of stick-slip. This refers to the jerky sliding of solid bodies moving against each other.

[0003] A hollow cylindrical damping element as a pressure stop buffer is known from DE 202 10 603 U1. An isolator / vibration damper for a vehicle radiator is known from DE 10 2005 029 996 A1 and CN 102 941 802 A. An anti-vibration device for a running gear is known from US 2002 / 0 021 655 A1. A vibration damper head bearing is known from EP 0 480 649 A1. A hinged support bearing is known from EP 2 251 218 A1. A vibration damper with a stop buffer is known from DE 43 36 034 A1. A hydraulic vibration damper is also known from DE 40 29 490 A1.

[0004] The present invention therefore aims to provide a vibration damper with an improved pressure stop buffer, avoiding the aforementioned disadvantages. In particular, this improved pressure stop buffer is intended to offer an alternative solution to known pressure stop buffers. Furthermore, the replacement of pressure stop buffers should be safe, quick, and flexible, thus enabling the rapid elimination of noise pollution. Disclosure of the invention

[0005] This problem is solved with a vibration damper with pressure stop buffer according to claim 1.

[0006] The vibration damper with pressure stop buffer according to the invention has the advantage over conventional pressure stop buffers that the physical effect of stick-slip can be specifically influenced and thus the noise emission can be reduced or eliminated.

[0007] The invention therefore relates to a vibration damper comprising a damper tube at least partially filled with damping fluid, in which a piston rod is movable back and forth, wherein a working piston is movable along with the piston rod, by which the interior of the damper tube is divided into a working chamber on the piston rod side and a working chamber away from the piston rod, at least one pressure stop buffer, wherein the pressure stop buffer comprises an outer contour for at least partial inclusion in a dome bearing housing and a hollow cylindrical basic structure with an inner contour for coaxial arrangement on a piston rod of the vibration damper, wherein the outer contour of the pressure stop buffer has a three-dimensionally structured surface with several protrusions and / or several depressions, at least in an area relating to the at least partial reception in the strut mount housing, and wherein the several protrusions and / or depressions are at least partially homogeneously distributed, at least in the area relating to the at least partial reception in the strut mount housing, wherein more than 5% of the several protrusions, at least in the area relating to the at least partial reception in the strut mount housing, have a height in a range of 0.2 to 0.3 mm relative to the zero plane of a forming tool with which the pressure stop buffer was manufactured. Detailed description of the invention

[0008] Within the scope of the present invention, a three-dimensionally structured surface is understood to be a surface which extends in at least three dimensions with respect to the design plane of the pressure stop buffer. The design plane corresponds to the so-called zero plane of a mold for manufacturing pressure stop buffers, wherein, in the manufacturing process, negative contours of the mold form the protrusions with respect to the zero plane and positive contours of the mold form the depressions with respect to the zero plane.

[0009] The three-dimensionally structured surface has several raised areas and / or several depressions.

[0010] Within the scope of the present invention, elevations and / or depressions are related to the design plane of the pressure stop buffer.

[0011] The multiple elevations and / or depressions are at least partially homogeneously distributed, at least in the area of ​​at least partial absorption in the strut mount housing.

[0012] In the context of the present invention, "homogeneously distributed" means a uniform distribution. For example, a uniform distribution exhibits a specific pattern on the structured surface.

[0013] According to a further embodiment of the invention, the multiple protrusions and / or depressions are at least partially heterogeneously distributed, at least in the area of ​​at least partial reception in the strut mount housing.

[0014] In the context of the present invention, "heterogeneously distributed" means an uneven distribution. For example, an uneven distribution does not exhibit a specific pattern on the structured surface.

[0015] The at least partially homogeneous and / or heterogeneous distribution can be arranged transversely and / or longitudinally to the circumferential direction of the pressure stop buffer.

[0016] According to a further embodiment of the invention, more than 25% of the protrusions, at least in the area of ​​at least partial absorption in the dome bearing housing, are greater than or equal to 0.1 mm with respect to the zero plane of a forming tool with which the pressure stop buffer was manufactured.

[0017] According to a further embodiment of the invention, less than 10% of the recesses, at least in the area of ​​at least partial reception in the dome bearing housing, have a depth in the range of 0.1 to 0.2 mm relative to the zero plane of a forming tool with which the pressure stop buffer was manufactured.

[0018] In a further embodiment of the invention, less than 5% of the recesses, at least in the area of ​​at least partial reception in the dome bearing housing, have a depth in the range of 0.2 to 0.3 mm relative to the zero plane of a forming tool with which the pressure stop buffer was manufactured.

[0019] According to a further embodiment of the invention, several clamping elements are arranged on the inner contour of the pressure stop buffer to form a clamping connection, whereby a clamping connection between the piston rod and the pressure stop buffer can be formed with the several clamping elements when the pressure stop buffer is arranged coaxially on the piston rod. Examples of clamping elements are clamping pads, clamping lamellae, clamping blocks and combinations thereof.

[0020] In a further embodiment of the invention, the several clamping elements have a geometrically shaped design that is at least partially threaded and are arranged in a threaded manner on the inner contour of the pressure stop buffer.

[0021] According to a further embodiment of the invention, the several clamping elements are grouped as clamping modules arranged in the longitudinal direction of the piston rod on the inner contour of the pressure stop buffer.

[0022] In a further embodiment of the invention, the several clamping elements and / or clamping modules are arranged in a spiral direction in opposite directions along the piston rod on the inner contour of the pressure stop buffer.

[0023] Within the scope of the present invention, "counter-clockwise" means that the slope of the multiple clamping elements and / or clamping modules alternately inverts in radial sequence, while the magnitude of the slope of the multiple clamping elements and / or clamping modules remains constant.

[0024] According to a further embodiment of the invention, the multiple clamping elements and / or clamping modules have a three-dimensionally structured surface at least in one area in relation to the coaxial arrangement on the piston rod.

[0025] According to a further embodiment of the invention, the three-dimensionally structured surface of the multiple clamping elements (10, 10', 10'', 10'''') and / or clamping modules (11, 11', 11") has multiple protrusions and / or multiple depressions.

[0026] In a further embodiment of the invention, the basic structure of the pressure stop buffer comprises a base of polyisocyanate polyaddition products, preferably based on cellular polyurethane elastomers, which may optionally contain polyurea structures, particularly preferably based on cellular polyurethane elastomers preferably with a density according to DIN 53420 of 200 to 1100 kg / m³ 3 preferably from 300 to 800 kg / m² 3 , a tensile strength according to DIN 53 571 of greater than or equal to 2 N / mm² 2 preferably from 2 to 8 N / mm 2 an elongation according to DIN 53571 of 300, preferably 300 to 700% and a tear strength according to DIN 53515 of greater than or equal to 8 N / mm, preferably 8 to 25 N / mm.

[0027] According to a further embodiment of the invention, the basic structure of the pressure stop buffer comprises a base made of a thermoplastic material. Examples of thermoplastic materials are all plastics suitable for injection molding. Suitable thermoplastic materials include polycondensates, polymers, and polyadducts. Suitable thermoplastic polycondensates are polyamides, in particular 6,6-polyamide, polycarbonates, polyesters, preferably polyterephthalates such as polyethylene terephthalate and polybutylene terephthalate, polyphenylene oxides, polysulfones, and polyvinyl acetates.Suitable thermoplastic polymers are polyolefins, in particular polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, as well as polyvinyl chloride, polyvinylidene chloride, polymethyl methacrylate, polyacrylonitrile, polystyrene, high-impact polystyrene, polyacetals, polyvinyl alcohols, polyvinyl acetate, polyoxymethylene, and poly-p-xylylene, or combinations thereof. Suitable thermoplastic polyadducts are, in particular, thermoplastic polyurethanes.

[0028] Other suitable thermoplastic materials, in particular thermoplastic polymers, are styrene-acrylonitrile copolymers (SAN), α-methylstyrene-acrylonitrile copolymers, styrene-methyl methacrylate copolymers and styrene-maleic acid nyride copolymers, as well as acrylonitrile-butadiene-styrene polymers (ABS), acrylonitrile-styrene-acrylate polymers (ASA), polyoxymethylene (POM), polyamide, polypropylene or combinations thereof.

[0029] Another aspect of the invention comprises a vibration damper comprising - a damper tube at least partially filled with damping fluid, in which a piston rod is movable back and forth, wherein a working piston is movable along with the piston rod, by which the interior of the damper tube is divided into a working chamber on the piston rod side and a working chamber away from the piston rod, - at least one pressure stop buffer, wherein the at least one pressure stop buffer has an outer contour for at least partial inclusion in a strut mount housing and a hollow cylindrical basic structure with an inner contour for coaxial arrangement on the piston rod of the vibration damper, wherein the outer contour of the pressure stop buffer has a three-dimensionally structured surface, at least in an area where it is at least partially recessed in the strut mount housing. The vibration damper may comprise further embodiments of the aforementioned pressure stop buffer according to the invention. Brief description of the drawings

[0030] The pressure stop buffer according to the invention is explained with reference to the drawings. Fig. Figure 1 schematically shows an oblique view of a pressure stop buffer according to an embodiment of the invention. Fig. Figure 2 schematically shows a longitudinal section of a pressure stop buffer according to Fig. 1 with clamping elements formed in the inner contour according to an embodiment of the invention, Fig. Figure 3 schematically shows a longitudinal section of a vibration damper with a pressure stop buffer according to Fig. 2 according to an embodiment of the invention.

[0031] In the Fig. Figure 1 is a schematic oblique view of a pressure stop buffer 1 with a hollow cylindrical base structure comprising an outer contour 4 and an inner contour 6. The outer contour 4 has a three-dimensional (topographic) surface structure 7. The three-dimensional (topographic) surface structure 7 has several protrusions (8, 8', 8'', 8''') and / or several depressions (9, 9', 9'', 9'''). The several protrusions (8, 8', 8'', 8''') and / or several depressions (9, 9', 9'', 9''') are at least partially homogeneously distributed. Several clamping elements 10, 10', 10'', 10''' are arranged on the inner contour 6 of the pressure stop buffer 1, with one clamping element 10 being shown by way of example.

[0032] In the Fig. Figure 2 is a schematic longitudinal section of the pressure stop buffer 1 according to Fig.Figure 1 shows the clamping elements 10, 10', 10'', 10''' formed in the inner contour 6. The pressure stop buffer 1 comprises the outer contour 4 and the inner contour 6, with the clamping elements 10, 10', 10'', 10''' of the inner contour 6 shown arranged. The multiple clamping elements 10, 10', 10'', 10''' shown have a threaded geometric design. Furthermore, the multiple clamping elements 10, 10', 10'', 10''' shown are grouped together as clamping modules 11, 11', 11''.

[0033] In the Fig. Figure 3 is a schematic longitudinal section of a vibration damper 2 with the pressure stop buffer 1 according to Fig. Figure 2 shows the pressure stop buffer 1. It is arranged coaxially on a piston rod 5 of the vibration damper 2 and is received in a dome bearing housing 3. The three-dimensional (topographical) surface structure 7 is formed at least in one area of ​​the at least partial receiving of the pressure stop buffer 1. Brief description of the experimental examples

[0034] Exemplary pressure-stop buffers according to the invention were manufactured using injection molding. A cellular elastomer (PUR (NDI) Cellasto MH24-45) was used as the plastic material. Subsequently, the surface of the manufactured pressure-stop buffer was scanned and evaluated using a 3D scanner. The three-dimensional (topographic) surface structure of the outer contour of the pressure-stop buffer was captured and evaluated using a 3D scanner. An ATOS Core 135 with ATOS Professional Software (V8 SR1) was used as the sensor for data acquisition, and the GOM Inspect Professional V8 SR1 from GOM, Gesellschaft für Optische Messtechnik mbH, Mittelweg 7-8, 38106 Braunschweig, Germany, was used for evaluation.

[0035] First, a reference surface, corresponding to the zero plane of the forming tool used, was constructed, and the surface comparison was performed against this surface. For this purpose, as many areas as possible of the "smooth base surface," i.e., the zero plane for the part to be analyzed, were selected, and a triangulated polynomial surface was constructed (Construct Surface Triangulated Polynomial Surface). In the software, "all" was selected as the parameter for surface degree 5 and for points used.

[0036] This area was converted into a CAD file using the CAD Actual Mesh operation, and a surface comparison was then performed on this CAD file.

[0037] The following Table 1 shows, by way of example, the evaluated data of a measurement series of the elevations and depressions of the three-dimensional surface structure of the outer contour of the pressure stop buffer according to the invention, measured with the 3D scan. Table 1: Raised and recessed areas of the three-dimensional surface structure of the outer contour of the pressure stop buffer according to the invention, measured by 3D scan. Min [mm] Max [mm] Percentage [%] 0,3 5 0,2 0,3 5 0,1 0,2 25 -0,1 0,1 40 -0,2 -0,1 10 -0,3 -0,2 5 -0,3 5

[0038] The following Table 2 shows, by way of example, the evaluated data of a measurement series of the elevations and depressions of the three-dimensional surface structure of the inventive inner contour of the pressure stop buffer measured with the 3D scan. Table 2: Raised and recessed areas of the three-dimensional surface structure of the inventive inner contour of several clamping elements of the pressure stop buffer, measured by 3D scan. Min [mm] Max [mm] Percentage [%] 0,3 5 0,2 0,3 5 0,1 0,2 25 -0,1 0,1 40 -0,2 -0,1 10 -0,3 -0,2 5 -0,3 5 Commercial applicability

[0039] Pressure stop buffers of the type described above are used in the production of vibration dampers, especially vibration dampers for motor vehicles. Reference symbol list 1 pressure stop buffer 2 vibration dampers 3 strut mount housings 4 Outer contour 5 piston rod 6 Inner contour 7 three-dimensionally structured surfaces 8, 8', 8'', 8''' elevation(s) 9, 9', 9'', 9''' Depth(s) 10, 10', 10'', 10''' clamping element(s) 11, 11', 11'' terminal module(s)

Claims

[1] vibration damper (2) comprising - a damper tube at least partially filled with damping fluid, in which a piston rod is movable back and forth, wherein a working piston is movable along with the piston rod, by which the interior of the damper tube is divided into a working space on the piston rod side and a working space away from the piston rod, - at least one pressure stop buffer (1), wherein the at least one pressure stop buffer (1) comprises an outer contour (4) for at least partial inclusion in a dome bearing housing (3) and a hollow cylindrical basic structure with an inner contour (6) for coaxial arrangement on a piston rod (5) of the vibration damper (2), characterized by , that the outer contour (4) of the pressure stop buffer (1) has at least in an area relating to the at least partial reception in the strut bearing housing (3) a three-dimensionally structured surface (7) with several protrusions (8, 8', 8'', 8''') and / or several depressions (9, 9', 9'', 9'''), wherein the multiple protrusions (8, 8', 8'', 8''') and / or depressions (9, 9', 9'', 9''') are at least partially homogeneously distributed, at least in the area of ​​at least partial reception in the strut bearing housing (3), wherein more than 5% of the multiple protrusions (8, 8', 8'', 8''') at least in the area of ​​at least partial reception in the strut bearing housing (3) have a height in the range of 0.2 to 0.3 mm relative to the zero plane of a forming tool with which the pressure stop buffer (1) was manufactured. [2] Vibration damper (2) with pressure stop buffer (1) according to claim 1, characterized by, that the multiple elevations (8, 8', 8'', 8''') and / or depressions (9, 9', 9'', 9''') are at least partially heterogeneously distributed, at least in the area of ​​the at least partial reception in the dome bearing housing (3). [3] Vibration damper (2) with pressure stop buffer (1) according to one of claims 1 to 2, characterized by , that several clamping elements (10, 10', 10'', 10''') are arranged on the inner contour (6) of the pressure stop buffer (1) to form a clamping connection, wherein a clamping connection between the piston rod (5) and the pressure stop buffer (1) can be formed with the several clamping elements (10, 10', 10'', 10''') when the pressure stop buffer (1) is arranged coaxially on the piston rod (5). [4] Vibration damper (2) with pressure stop buffer (1) according to claim 3, characterized by, that the several clamping elements (10, 10', 10'', 10''') have at least a threaded geometric design in sections and are arranged thread-like on the inner contour (6) of the pressure stop buffer (1). [5] Vibration damper (2) with pressure stop buffer (1) according to one of claims 3 to 4, characterized by , that the several clamping elements (10, 10', 10'', 10''') are grouped as clamping modules (11, 11', 11'') in the longitudinal direction of the piston rod on the inner contour (6) of the pressure stop buffer (1). [6] Vibration damper (2) with pressure stop buffer (1) according to one of claims 3 to 5, characterized by , that the multiple clamping elements (10, 10', 10'', 10'''') and / or clamping modules (11, 11', 11'') are arranged in a spiral direction in opposite directions in the longitudinal direction of the piston rod on the inner contour (6) of the pressure stop buffer (1). [7] Vibration damper (2) with pressure stop buffer (1) according to one of claims 3 to 6, characterized by, that the multiple clamping elements (10, 10', 10'', 10'''') and / or clamping modules (11, 11', 11'') have a three-dimensional structured surface (7) at least in one area in relation to the coaxial arrangement on the piston rod (5). [8] Vibration damper (2) with pressure stop buffer (1) according to claim 7, characterized by , that the three-dimensionally structured surface (7) of the multiple clamping elements (10, 10', 10'', 10''') and / or clamping modules (11, 11', 11'') has multiple protrusions (8, 8', 8'', 8''') and / or multiple depressions (9, 9', 9'', 9''').

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