Vibration damper with a gas-filled casing

Abstract

Vibration damper (1) comprising a working cylinder (3) filled with damping medium, which forms a fluid channel (19) with an outer shell surface (15) and an intermediate tube (17) arranged on this shell surface (15), wherein the working cylinder (3) forms an annular space with an outer container tube (25) which acts as a compensation space (27) and in which a shell body (29) with a gas filling (31) is arranged, characterized in that the intermediate tube (17) is designed with a mounting protection element (39) which at least partially covers an end face (35) of the intermediate tube (17) opposite a mounting direction of the shell body (29), wherein the mounting protection element (39) has the same outer diameter as the intermediate tube (17) at the transition to the intermediate tube (17) and has a closed surface structure in the circumferential area of ​​a sliding surface (41) for the shell body (29).

Description

[0001] The invention relates to a vibration damper with a gas-filled encapsulation body according to the preamble of claim 1.

[0002] From DE 10 2020 201 457 A1, an adjustable vibration damper is known which has an intermediate tube which, together with a cylinder, forms a fluid connection between a piston rod-side working chamber and an adjustable damping valve device. The intermediate tube has end-end guide sections with a chambered seal, wherein the intermediate tube is frictionally fixed to the cylinder via the guide sections.

[0003] Such a vibration damper is also equipped with a gas-filled casing according to the design of DE 10 2015 218 296 A1. The manufacture and assembly of such an intermediate tube has disadvantages. Furthermore, great care must be taken when assembling the casing within a compensation chamber to avoid damaging its relatively thin shell.

[0004] A generic vibration damper is known from KR 10 2005 0104250 A1, which according to the Fig. 2. An elastic container for a gas volume. An intermediate tube is closed at its end by a sealing guide set that extends completely within the intermediate tube. An end face and a transition edge between the end face and an outer shell surface of the intermediate tube are uncovered within the compensation space.

[0005] The DE 103 20 005 B3 shows with the Fig. 6. A vibration damper with a support tube which, together with a cylinder, defines an annular space for a compensating element. The support tube is fixed to the piston rod guide. During assembly, a gas bag is axially secured between a bent end of the support tube and a shoulder of the piston rod guide and can thus be inserted into the cylinder as a protected assembly.

[0006] The object of the present invention is to simplify the use of a gas-filled encapsulation body in a vibration damper.

[0007] The problem is solved by the features of claim 1.

[0008] The advantage of the invention is that the intermediate tube can be designed solely for its function as an intermediate tube. An intermediate tube with a constant cross-section can be used, which is significantly more cost-effective than the prior art design.

[0009] Furthermore, the mounting protection element can, for example, have a conical or convex shape. This dimensioning of the outer diameter avoids any obstruction during transition.

[0010] The closed surface structure, i.e., the absence of grooves, ridges, or the like, is intended to achieve the gentlest possible frictional contact between the casing and the mounting protection element.

[0011] Preferably, the mounting protection element is formed by a cap separate from the intermediate tube. The mounting protection element only needs to withstand the mechanical stress present during installation.

[0012] With a view to a simple design and the goal of being able to use a simple working cylinder, the mounting protection element is force-fitted to the outer surface of the working cylinder.

[0013] To ensure sufficient inherent stability, the mounting protection element has a ribbed structure on the inside.

[0014] The ribbed structure also allows for clamping surfaces to be incorporated into the outer surface of the working cylinder. This enables larger dimensional tolerances in the working cylinder to be accommodated without causing excessive stress in the mounting protection element.

[0015] Another measure for a simple design is that the axial connection between the mounting protection element and the intermediate tube is designed as a butt joint. Consequently, a thin-walled intermediate tube can also be used, as no special connecting profile to the mounting protection element is required.

[0016] During the installation of the vibration damper, air pockets sometimes form within it. Therefore, an annular space enclosed by the mounting protection element is connected to the compensation chamber via at least one connection opening. During operation of the vibration damper, any air pockets present in the compensation chamber can be expelled via the pumping process between the compensation chamber and the working chamber.

[0017] To ensure the removal of air inclusions as quickly and reliably as possible, the mounting protection element is equipped with at least one connection opening at each end. This allows the annular space to be flushed by the vapor medium, which is set in motion in the compensation chamber via the flow between the connected working chamber and the compensation chamber, thereby removing air inclusions from the annular space.

[0018] The following description of the figures will be used to explain the invention in more detail.

[0019] It shows: Fig. 1 Sectional view through a vibration damper according to the invention Fig. 2 and 3 Detailed illustrations regarding the assembly process Fig. 4 and 5 Mounting protection element in different views Fig. 6 Sectional view through vibration damper in the assembled state

[0020] The Fig. Figure 1 shows an example of a vibration damper 1 with a working cylinder 3 filled with damping medium. A piston rod 5 with a piston 7 is guided axially within the working cylinder 3. The piston 7 divides the working cylinder 3 into a working chamber 9 on the piston rod side and a working chamber 11 on the other side. Depending on the desired function of the vibration damper 1, the piston 7 can be designed as a closed displacer, with at least one pressure relief valve, or with damping valves known per se. The working chamber 9 on the piston rod side is closed at its end by a piston rod guide 13.

[0021] An outer surface 15 of the working cylinder 3 and an intermediate tube 17 arranged on this surface 15 form a fluid channel 19. The fluid channel 19, via at least one connecting opening 21, can serve as a flow connection between the piston rod-side working chamber 9 and an adjustable damping valve assembly 23, but also for a connection with the working chamber 11 furthest from the piston rod or a bottom valve (not shown). The specific function of the fluid channel 19 is irrelevant to the invention.

[0022] Furthermore, the working cylinder 3 forms an annular space with an outer reservoir tube 25, which acts as a compensation chamber 27 for the volume of damping medium displaced by the piston rod 5. The piston rod guide 13 also seals the compensation chamber 27 at its end and is sealed to the reservoir tube 25.

[0023] The compensation chamber 27 is filled with a volume of damping medium and additionally accommodates a shell 29 containing a gas filling 31. The gas filling 31 maintains the volume of damping medium under pressure preload to minimize foaming of the damping medium.

[0024] The intermediate tube 17 is designed as a rigid tubular body, the open end of which, pointing towards the piston rod guide 13, is closed by a sealing guide set 33. Due to the operating pressures that occur, the intermediate tube is often made of a metallic material. However, the choice of material is not relevant to the invention. The sealing guide set 33 is located at an axial distance from an end face 35 of the intermediate tube 17. This results in a short annular space 37 between the intermediate tube 17 and the working cylinder 3, as shown in the detailed illustration according to the Fig. 2 and Fig. Show 3.

[0025] The intermediate tube 17 is equipped with a mounting protection element 39, which at least partially covers the end face 35 of the intermediate tube 17 opposite the mounting direction of the housing body 29. Specifically, the mounting protection element is oriented towards the piston rod guide 13. The mounting protection element 39 is formed by a cap separate from the intermediate tube 17. The mounting protection element 39 is force-fitted to the outer surface 15 of the working cylinder 3 and is located entirely within the damping medium volume inside the compensation chamber 27. The pressure level inside the compensation chamber 27 is significantly lower than the peak pressure inside the intermediate tube 17, so the mounting protection element 39 can easily be made of a plastic material.

[0026] The mounting protection element 39 has the same outer diameter at the transition to the intermediate tube 17 as the intermediate tube 17. An axial connection between the mounting protection element 39 and the intermediate tube 17 is designed as a butt joint. The mounting protection element 39 also rests against the working cylinder 3 with a minimal end face, resulting in a conical basic shape. A convex contour or a hollow profile can also be provided. The mounting protection element 39 has a sliding surface 41 around its circumference for the housing body 29. This sliding surface 41, in turn, has a closed surface structure to ensure optimal sliding properties.

[0027] How the synthesis of Fig. 4 and Fig. As shown in Figure 5, the mounting protection element 39 has an internal ribbed structure 43. The ribbed structure 43 extends over the entire circumference and is axially limited to a longitudinal section. Between the adjacent ribs of the ribbed structure 43, zones 45 are present, which provide a certain degree of elasticity to the mounting protection element 43, thus compensating for a certain degree of out-of-roundness of the working cylinder 3. Furthermore, the ribbed structure 43 is provided with clamping surfaces 47 for the outer surface 15 of the working cylinder 3.

[0028] An annular space 49 enclosed by the mounting protection element 39 is connected to the compensation space 27 via at least one connection opening 51; 53. The annular space 49 is connected to the annular space 37. Preferably, the mounting protection element is provided at both ends with at least one connection opening 51; 53. The connection openings 51; 53 are formed by axial grooves to the working cylinder and radial grooves to the intermediate tube 17.

[0029] The Fig. Figure 6 shows the vibration damper 1 after the Fig. 1 within the assembly process. The container tube 25 and the working cylinder 3 are not yet connected to the piston rod guide 13. The position of the casing body 29 relative to the intermediate tube 17 corresponds to the illustration. Fig. 3. The casing body 29 is connected to the piston rod guide via a filling port 55.

[0030] During a further assembly movement, the casing body 29 slides over the assembly protection element 39 deeper into the compensation chamber 27. After completion of the assembly, the casing body 29 continues to rest against the assembly protection element 39, as shown in the Fig. 1 and Fig. 3 show. The connection openings 51; 53 remain at least partially open and allow the degassing of the annular space 49 of the mounting protection element 39. Reference sign 1 vibration damper 3 working cylinders 5 piston rod 7 pistons 9 piston rod-side working space 11 working space far from piston rod 13 Piston rod guide 15 lateral surface area 17 Intermediate pipe 19 Fluid channel 21 Connecting opening 23 Damping valve device 25 Container pipe 27 compensation area 29 Enclosing bodies 31 Gas filling 33 Seal guide set 35 End face of the intermediate tube 37 annular space 39 Mounting protection element 41 Sliding surface 43 rib structure 45 zone 47 clamping surface 49 Ring space 51 Connection opening 53 Connection opening 55 Filling port

Claims

[1] Vibration damper (1) comprising a working cylinder (3) filled with damping medium, which forms a fluid channel (19) with an outer shell surface (15) and an intermediate tube (17) arranged on this shell surface (15), wherein the working cylinder (3) forms an annular space with an outer container tube (25) which acts as a compensation space (27) and in which a shell body (29) with a gas filling (31) is arranged, characterized by , that the intermediate tube (17) is provided with a mounting protection element (39) which at least partially covers an end face (35) of the intermediate tube (17) opposite a mounting direction of the shell body (29), wherein the mounting protection element (39) has the same outer diameter as the intermediate tube (17) at the transition to the intermediate tube (17) and has a closed surface structure in the circumferential area of ​​a sliding surface (41) for the shell body (29). [2] Vibration damper (1) according to claim 1, characterized by, that the mounting protection element (39) is formed by a cap separate from the intermediate tube (17). [3] Vibration damper (1) according to at least one of claims 1 or 2, characterized by , that the mounting protection element (39) is force-fitted to the outer surface (15) of the working cylinder (3). [4] Vibration damper (1) according to at least one of claims 1 to 3, characterized by , that the mounting protection element (39) has a ribbed structure (43) on the inside. [5] Vibration damper (1) according to claim 4, characterized by , that the rib structure (43) is provided with clamping surfaces (47) to the outer surface (15) of the working cylinder (3). [6] Vibration damper (1) according to at least one of claims 1 to 5, characterized by , that the axial connection between the mounting protection element (39) and the intermediate tube (17) is designed as a butt joint. [7] Vibration damper (1) according to at least one of claims 1 to 6, characterized by , that an annular space (49) enclosed by the mounting protection element (39) is connected to the compensation space (27) via at least one connection opening (51; 53). [8] Vibration damper (1) according to claim 7, characterized by , that the mounting protection element (39) is provided at both ends with at least one connection opening (51; 53).

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