Vibration Damper, And Piston Valve For A Vibration Damper

Abstract

A vibration damper includes a piston rod (2) which transitions into a piston rod neck (4) while forming a contact shoulder (6) and guides a piston valve (1) at this piston rod neck (4), this piston valve (1) is pretensioned against the contact shoulder (6) of the piston rod (2). To reduce variances in damping force in batch fabrication of the vibration damper, a compensating disk (20) is fitted axially between the contact shoulder (6) and the piston valve (1), which compensating disk (20) is produced from a material with a lower yield strength compared to the piston rod (2) and/or compared to an immediately succeeding component of the piston valve (1).

Claims

1-10. (canceled)

11. A vibration damper comprising: a piston valve (1); a piston rod (2) having a piston rod neck (4) for carrying said piston valve (1); a contact shoulder (6) between said piston rod (2) and said piston rod neck (4); said piston valve (1) being pretensioned against said contact shoulder (6) of said piston rod (2); a compensating disk (20) fitted axially between said contact shoulder (6) and said piston valve (1), said compensating disk constructed from a material having a lower yield strength than a material forming said piston rod (2) and/or a material forming a component of said piston valve (1) immediately succeeding said piston rod (2).

12. The vibration damper according to claim 1, wherein said piston valve (1) comprises a piston body (7) having at least one passage (15) extending axially therethrough, said at least one passage (15) having an orifice (16); wherein said at least one passage (15) can be covered at each said orifice (16) with at least one valve disk, and wherein said piston body (7) and said at least one valve disk are placed between supporting disks (12, 13) on said piston rod neck (4).

13. The vibration damper according to claim 12, wherein said at least one passage (15) can be covered at each said orifice (16) with a valve disk package (9).

14. The vibration damper according to claim 12, additionally comprising an intermediate disk, and wherein said at least one valve disk contacts said intermediate disk (10; 11) on a side remote of said piston body (7), said intermediate disk (10; 11) extending radially over a portion of said at least one valve disk.

15. The vibration damper according to claim 11, wherein said piston valve (1) is a piston valve according to claim 18.

16. A method of assembling a vibration damper according to claim 11, comprising: initially sliding the compensating disk (20) and at least the immediately succeeding component of the piston valve (1) onto the piston rod neck (4) of the piston rod (2) against the contact shoulder (6); subsequently tensioning the compensating disk (20) and the at last immediately succeeding component of the piston valve (11) with a preload against the contact shoulder (6), the preload being above a subsequent assembly pretensioning force; and fastening the complete piston valve (1) to the piston rod neck (4) accompanied by pretensioning with the assembly pretensioning force.

17. A piston valve (21) for a vibration damper comprising: a piston body (22) placed axially between supporting disks (26), wherein at least one of the supporting disks (26) on an axial side (27) facing the piston body (22) is constructed so as to be at least partially concavely curved, while the piston body (22) is convexly curved at least partially at an axial side (28) facing the at least one supporting disk (26).

18. The piston valve (21) according to claim 17, wherein the piston body (22) is axially penetrated by at least one passage having an orifice, said at least one passage can be covered with at least one valve disk at each said orifice.

19. The piston valve (21) according to claim 18, wherein said at least one passage can be covered at at least one of said orifice with a valve disk package (23).

20. The piston valve (21) according to claim 18, wherein said at least one valve disk contacts an intermediate disk (25) on a side remote of the piston body (22), said intermediate disk (25) extending radially over a portion of said at least one valve disk.

21. The vibration damper according to claim 19, wherein said piston valve (1) is a piston valve according to claim 18.

22. A method of assembling a vibration damper according to claim 20, comprising: initially sliding the compensating disk (20) and at least the immediately succeeding component of the piston valve (1) onto the piston rod neck (4) of the piston rod (2) against the contact shoulder (6); subsequently tensioning the compensating disk (20) and the at last immediately succeeding component of the piston valve (11) with a preload against the contact shoulder (6), the preload being above a subsequent assembly pretensioning force; and fastening the complete piston valve (1) to the piston rod neck (4) accompanied by pretensioning with the assembly pretensioning force.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Advantageous embodiments of the invention are described in the following and shown in the drawings in which:

[0026] FIG. 1 is a sectional view of a part of a vibration damper according to a preferred embodiment form of the invention shown in the region of a piston valve;

[0027] FIG. 2 is a view of a detail Z from FIG. 1; and

[0028] FIG. 3 is a sectional view of a vibration damper in the region of a piston valve which is realized in accordance with a preferred configuration of the invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0029] FIG. 1 shows a sectional view of a portion of a vibration damper according to a preferred embodiment form of the invention which is shown in the region of a piston valve 1. Part of a piston rod 2 of the vibration damper can be seen. The outer diameter of this piston rod 2 decreases at the axial end via a step 3 to a piston rod neck 4. The piston rod 2 carries the piston valve 1 at this piston rod neck 4, the piston valve 1 being pretensioned against a contact shoulder 6 of the piston rod 2 via a fastening nut 5. This contact shoulder 6 is defined through step 3 and is provided as a substantially axially oriented annular contact surface.

[0030] The fastening nut 5 is fitted by an internal threadnot shown furtherto a corresponding external thread of the piston rod neck 4 and pretensions the piston valve against the contact shoulder 6. The piston valve comprises a plurality of components in the form of a piston body 7, valve disk packages 8 and 9, associated intermediate disks 10 and 11, and two supporting disks 12 and 13.

[0031] As can further be seen from FIG. 1, the piston body 7 carries a seal 14 at an outer diameter. The piston body 7 makes contact with a circumferential cylindrical tubenot shown in more detailof the vibration damper via this seal 14 which serves to seal a gap between the piston body 7 and cylindrical tube. Further, the piston body 7 is axially penetrated by a plurality of passages, of which only one passage 15 is visible in the section plane of FIG. 1, which allow a damping medium to pass between spaces of the vibration damper which are separated from one another by the piston body 7.

[0032] Over the course of the in-and-out movements of the piston rod 2 and, therefore, also of the piston body 7, there is a displacement of the damping medium between the separate spaces of the vibration damper. The damping medium is displaced through the passages 15 of the piston body 7 from one space to the other. The passages are covered in the region of their orifices, which are oriented toward each axial side of the piston body 7, via the valve disk package 8 and 9, respectively, at that location. In the case of orifice 16 of passage 15, this is valve disk package 9.

[0033] The respective orifice is released only after a certain pressure has been reached in the associated passages, which pressure is sufficient to lift the respective valve disk package 8 and 9, respectively, from an associated valve disk 17 and 18, respectively. Accordingly, the valve disk packages 8 and 9, respectively, influence the flow of the damping medium via the passages and subject it to resistance.

[0034] A defined bending of the individual valve disks of the valve disk packages 8 and 9 is realized by the associated intermediate disk 10 and 11, respectively, which additionally axially contacts the outermost valve disk of the respective valve disk package 8 and 9, respectively, for this purpose and overlaps the latter radially with the valve disks, after which the bending is to take place.

[0035] However, the configuration of the step 3 of the piston rod 2 and, therefore, the definition of the contact shoulder 6 are subject to tolerances related to manufacture which can result in shape deviations of the contact shoulder 6 in batch fabrication of the vibration damper. In particular, an angle a can have deviations, which angle a, as is shown by detail Z in FIG. 2, is defined by an outer diameter 19 of the piston rod neck 4 and the contact shoulder 6. Ideally, this angle a is exactly 90 so that an exactly axially oriented contact surface is defined for the piston valve 1. However, in the course of tolerance-dependent shape deviations, angle a can also be greater than or less than 90, which would result in loss of preload in the first case and in an increased pretensioning of the valve disk packages 8 and 9 in the second case.

[0036] In order to compensate for the above-mentioned tolerance-dependent shape deviations of the contact shoulder 6, the vibration damper according to the invention has as a special feature a compensating disk 20 which is fitted on the piston rod neck 4 axially between the piston valve 1 and contact shoulder 6. This compensating disk 20 is produced from a material having a lower yield strength than the material of the piston rod 2 and also of the immediately adjacent component of the piston valve 1 in the form of the supporting disk 12. As a result, the compensating disk 20 deforms plastically when a defined preload is applied and contacts the contact shoulder 6 and supporting disk 12 in positive engagement so that shape deviations are compensated.

[0037] To assemble the piston valve 1 on the piston rod 2, the compensating disk 20 and supporting disk 12 are first slid on the piston rod neck 4 and subsequently pretensioned with the preload against the contact shoulder 6 so that the above-mentioned plastic deformation of the compensating disk 20 occurs. Subsequently, the remaining components of the piston valve 1 are also guided on the piston rod neck 4 and pretensioned against the contact shoulder 6 by means of the fastening nut 5 by applying an assembly pretensioning force, i.e., a defined tightening torque of the nut, this assembly pretensioning force being smaller than the preload for the plastic deformation of the compensating disk 20.

[0038] FIG. 3 shows a sectional view of a part of a vibration damper in the region of a piston valve 21 which is realized according to a preferred embodiment of the invention. This piston valve 21 comprises a piston body 22 which is axially penetratednot shownby at least one passage. An orifice of this passage is covered via a valve disk package 23 which is pretensioned against an associated valve seat 24 of piston body 22.

[0039] The valve disk package 23 releases the respective orifice of the respective passage after reaching a certain pressure in the passage, wherein a defined bending of the valve disks of the valve disk package 23 is shown via an axially adjacent intermediate disk 25. This intermediate disk 25 extends radially to the extent beyond which the desired bending of the valve disks of the valve disk package 23 is to take place.

[0040] A corresponding valve disk package and an associated intermediate disk are preferably provided on the opposite axial side of the piston body 22 which is not shown in FIG. 3. All of the components which are accordingly provided are received axially between two supporting disks, of which only supporting disk 26 is shown in FIG. 3.

[0041] To increase a pretensioning of the valve disks of the valve disk package 23 against the valve seat 24 and, accordingly, to reduce the risk of damping force variances in batch fabrication of the piston valve 21, the supporting disk 26 and the piston body 22 are outfitted with curvatures 29 and 30, respectively, on facing sides 27 and 28. The concave curvature 29 extends from an inner diameter of the supporting disk 26 radially along a portion of the side 27, while the convex curvature 30 is carried out along the entire radial extension of the side 28 of the piston body 22. Since consequently the contact surfaces for the valve disks of the valve disk package 23 and of the intermediate disk 25 are also not axial but are curved, the pretensioning of the valve disks of the valve disk package 23 against the valve seats 24 is ultimately increased.

[0042] Consequently, damping force variances in batch fabrication can be appreciably reduced by means of the configuration according to the invention of a vibration damper and a piston valve.

[0043] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.