DE102008041995A1 - Vibration damper i.e. single-tube vibration damper, for use in vehicle, has outlet formed by open annular gap between shell of piston rod guide and inner wall of cylinder, and closing part arranged in gap - Google Patents

Abstract

The damper (1) has a cylinder (5) filled with a damping medium, and a piston rod (7) guided into the cylinder from a piston rod guide (3). The guide with a shell (17) lies at an inner wall (19) of the cylinder, and is sealed in a direction of a piston rod-sided working chamber (11). A contact region between the shell and the cylinder has an outlet (29), corresponding to the chamber, in a direction of an outer front surface (31) of the guide. The outlet is formed by an open annular gap between the shell and the inner wall, and a closing part (35) i.e. cap, is arranged in the gap.

Description

The The invention relates to a piston rod guide for a monotube vibration damper according to The preamble of claim 1.

at Vibration dampers in the single-pipe design are many times all components and the working media over the open end mounted or filled the cylinder. The cylinder closing piston rod guide features on the outer diameter via a first groove for a sealing ring and, axially towards the outer Offset face, over a second groove, in the cylinder partially for the axial fixation of the piston rod guide is dipped. During assembly, the vibration damper must be completely filled with oil, so that the cylinder is filled with a certain surplus becomes. Therefore, the damping medium in the assembly of the Piston rod guide, in particular due to the damping medium wetted mounting device, get into the second groove. When sifting, part of it will be in the second groove Damping medium in the direction of the outer face repressed. This excess damping medium can be external be removed with little effort. However, that is still critical to evaluate in the second groove located damping medium. During further assembly, but also at a later date, z. B. during assembly of the vibration in the vehicle, urges the damping medium trapped in the second groove from the gap between the cylinder and the piston rod guide in Direction of the face. Purely external can give the impression that the vibration damper leaking is. Only a check in a testing machine gives information, whether the vibration damper is defective, or whether a so-called "sham oiler" is present.

It There was also the idea that the second groove with the percolation in the direction of the piston rod side working space and the first groove for the seal in the direction of the end face of the vibration damper shifts. But you can not exclude that during the seepage very fine cracks arise in the cylinder, which then leads to a leakage of the vibration damper to lead.

From the DE 10 2005 041 230 A1 a piston rod guide for a monotube vibration damper is known in which an upper portion of an outer circumferential surface is provided with a knurling to dissipate excess oil from the assembly process. Alternatively, a curved groove for the filling of the cylinder with the piston rod is presented.

For the knurling of the piston rod is another work step necessary. Furthermore, the function of the piston rod guide Suffer. In the alternative variant with the curved infiltration the procedure becomes more complicated, since one from the outside can not tell at what distance to the top of the cylinder the seepage must be done to the groove too to meet.

task The present invention addresses the problem of assembly-related oil contamination to fix at a vibration damper.

According to the invention the task solved that the outflow of a open annular gap between the outer lateral surface the piston rod guide and the inner wall of the cylinder is formed, wherein a closure member disposed in the annular gap is.

Of the Annular gap can be dimensioned so large that z. B. a Extractor or a cleaning device, the piston rod excess oil can remove.

In Another advantageous embodiment has the piston rod guide a diameter reduction starting from an outer one Face on. The diameter reduction can be practically cost neutral be prepared because the piston rod guide very often is generated by sintering.

According to one advantageous subclaim is the closure part as a cap with a passage opening for the piston rod executed. The annular component engages evenly in the annular gap and thus assumes a support function for the piston rod guide. The cap is over fixed a press fit in the annular gap.

Of the Use of the cap has the advantage that the cap in addition can carry a sealing element to the piston rod.

Based The following description of the figures is intended to illustrate the invention in more detail be explained.

The only one is limited to the representation of a vibration damper 1 in the area of a piston rod guide 3 , The vibration damper comprises a cylinder 5 in which a piston rod 7 with a piston 9 is guided axially movable. The piston 9 divides the cylinder filled with damping medium, preferably a hydraulic damping medium, into a piston rod-side and a piston rod-distant working chamber 11 ; 13 , The piston rod guide 3 centers the piston rod 7 and has at its inner diameter via a piston rod seal 15 , Over its lateral surface 17 the piston rod guide is supported 3 radially on an inner wall 19 from the cylinder.

Starting from the piston rod side working space 11 is a first groove 21 the piston rod guide 3 a cylinder seal 23 chambered, so that no damper medium from the cylinder during vibration damper operation 5 can escape.

During assembly of the vibration damper, the cylinder is open at the end 5 filled with the oily damping medium. Then push the piston together with the piston rod into the cylinder. This assembly step can be performed on a horizontally or vertically located cylinder. In any case, damping medium is located in the cylinder receiving mounting device. Finally, push the piston rod guide 3 on the piston rod until the piston rod guide has reached the mounting position shown. In this mounting condition has u. U. between the lateral surface 17 the piston rod guide and the inner wall 19 of the cylinder relative to the piston rod side working space 11 beyond poetry 23 Oil collected, especially in a second groove 25 that have a number of beads 27 for axially fixing the piston rod guide within the cylinder receives.

The said oil between the inner wall 19 and the lateral surface 17 is characterized by at least one outflow in the form of an annular gap 29 in the direction of an outer end face 31 the vibration damper dissipated and can be easily removed there in the further manufacturing process. The annular gap 29 extends from the second groove 25 to the outer end face 31 , For this, the piston rod guide has a diameter reduction 33 starting from the outer end face 31 on. Alternatively, one can also the annular gap by an increase in diameter on the inner wall 19 of the cylinder 5 To run. At the end of the manufacturing and, if necessary, cleaning process becomes a closure part 35 in the annular gap 29 arranged. The closure part 35 is as a cap with a through hole 37 for the piston rod 7 executed and is via a press fit in the annular gap 29 fixed.

The cap 35 can, if required, very easily an additional sealing element 39 to the piston rod 7 wear.

1

vibration

3

Piston rod guide

5

cylinder

7

piston rod

9

piston

11 13

workrooms in the cylinder

15

Piston rod seal

17

lateral surface the piston rod guide

19

inner wall of the cylinder

21

first Groove for cylinder seal

23

cylinder seal

25

second groove

27

beading

29

annular gap

31

outer Face of the piston rod guide

33

Diameter reduction the piston rod guide

35

closing part (Cap)

37

Through opening in the cap

39

additional poetry

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102005041230 A1 [0004]

Claims (5)

Vibration damper ( 1 ) comprising a cylinder filled with damping medium ( 5 ), in which a piston rod ( 7 ) of a piston rod guide ( 3 ) is guided axially movable, wherein the piston rod guide ( 3 ) with its lateral surface ( 17 ) on an inner wall ( 19 ) of the cylinder ( 5 ) and in the direction of a piston rod side working space ( 11 ) is sealed, wherein the contact area between the lateral surface ( 17 ) and the cylinder ( 5 ) relative to the piston rod side working space ( 11 ) beyond the sealing point ( 23 ) an outflow ( 29 ) in the direction of an outer end face ( 31 ) of the piston rod guide ( 3 ), characterized in that the outflow from an open annular gap ( 29 ) between the outer surface ( 19 ) of the piston rod guide ( 3 ) and the inner wall ( 19 ) of the cylinder ( 5 ) is formed, wherein a closure part ( 35 ) in the annular gap ( 29 ) is arranged. Vibration damper according to claim 1, characterized in that the piston rod guide ( 3 ) a diameter reduction ( 33 ) starting from the outer end face ( 31 ) having. Vibration damper according to claim 1, characterized in that the closure part ( 35 as a cap with a passage opening ( 37 ) for the piston rod ( 7 ) is executed. Vibration damper according to claim 3, characterized in that the cap ( 35 ) via a press fit in the annular gap ( 29 ) is fixed. Vibration damper according to claim 3, characterized in that the cap ( 29 ) a sealing element ( 39 ) to the piston rod ( 7 ) wearing.