SHOCK-ABSORBING DAMPER WITH A SPRING PLATE FASTENED THERETO, AND METHOD FOR THE FASTENING OF A SPRING PLATE TO A SHOCK-ABSORBING DAMPER

Abstract

A device for damping vibrations may comprise a hollow damper tube, a piston rod with a piston fastened thereto, at least one spring plate, and at least one securing element. The piston may be disposed within the damper tube, and the spring plate may be disposed outside the damper tube. To achieve a reliable connection between the spring plate and the damper tube in a cost-effective manner, the spring plate may be connected to the damper tube in both a force-fitting manner and a form-fitting manner. The present disclosure further concerns motor vehicles that employ such devices, as well as methods for fastening spring plates to damper tubes.

Claims

1.-15. (canceled)

16. A device for damping vibrations, the device comprising: a hollow damper tube; a piston rod to which a piston is fastened, wherein the piston is disposed within the hollow damper tube; a spring plate disposed outside the hollow damper tube, wherein the spring plate is connected to the hollow damper tube in both a force-fitting manner and a form-fitting manner; and a securing element.

17. The device of claim 16 wherein the securing element connects the spring plate to the hollow damper tube in a form-fitting manner.

18. The device of claim 16 wherein the spring plate is connected to the hollow damper tube in the force-fitting manner by a press-fit connection.

19. The device of claim 16 wherein the spring plate is connected to the securing element in a force-fitting manner by a press-fit connection.

20. The device of claim 16 wherein the securing element comprises a securing ring.

21. The device of claim 16 wherein the securing element comprises a snap ring.

22. The device of claim 16 wherein the hollow damper tube comprises a groove for receiving the securing element.

23. The device of claim 22 wherein the groove is molded into an outer surface of the hollow damper tube and is annularly encircling.

24. The device of claim 16 wherein the spring plate is configured in an annular design and is disposed around the hollow damper tube.

25. The device of claim 16 wherein the spring plate comprises a step.

26. The device of claim 25 wherein the step is disposed on an inner side of the spring plate and is annularly encircling.

27. The device of claim 16 wherein the spring plate comprises metal.

28. The device of claim 16 wherein the spring plate comprises aluminum.

29. A motor vehicle comprising a device for damping vibrations, wherein the device comprises: a hollow damper tube; a piston rod to which a piston is fastened, wherein the piston is disposed within the hollow damper tube; a spring plate disposed outside the hollow damper tube, wherein the spring plate is connected to the hollow damper tube in both a force-fitting manner and a form-fitting manner; and a securing element.

30. A method for fastening a spring plate to a damper tube, the method comprising: providing a damper tube, a securing element, and a spring plate; molding a groove into the damper tube; inserting the securing element into the groove; pushing the spring plate onto the damper tube; and producing a press-fit connection between the spring plate and the damper tube by plastic deformation of the spring plate.

31. The method of claim 30 wherein the producing of the press-fit connection comprises moving at least two tools in an axial direction that act on both sides of the spring plate.

32. The method of claim 31 further comprising pushing the at least two tools onto the damper tube, wherein the at least two tools are annularly encircling.

33. The method of claim 31 wherein the at least two tools include projections with which the at least two tools act on the spring plate.

Description

[0027] The invention is explained in more detail below with reference to a drawing which illustrates merely one preferred exemplary embodiment. In the drawing:

[0028] FIG. 1: shows a device according to the invention in a sectioned view,

[0029] FIG. 2A: shows an enlarged detailed view of that region of the device which is denoted by II in FIG. 1, during a first production step,

[0030] FIG. 2B: shows an enlarged detailed view of that region of the device which is denoted by II in FIG. 1, during a second production step, and

[0031] FIG. 2C: shows an enlarged detailed view of that region of the device which is denoted by II in FIG. 1, after production has finished.

[0032] FIG. 1 illustrates a device 1 according to the invention for damping vibrations. The device 1 comprises a damper tube 2 which is shaped cylindrically and has a longitudinal axis 3 running in the axial direction. The damper tube 2 is of hollow design and in its interior can receive a liquid (not illustrated in FIG. 1), for example oil. The device 1 also comprises a piston rod 4, to the lower end of which a piston 5 is fastened. The piston rod 4 is arranged centrally in the damper tube 2 and therefore runs along the longitudinal axis 3. The piston 5 has at least one piston valve 6 and an encircling seal 7. The seal 7 prevents the liquid present in the damper tube 2 from flowing past the piston 5 during a movement of the piston 5. The liquid can therefore flow only through the piston valves 6, with flow energy being converted into heat.

[0033] The device 1 illustrated in FIG. 1 also comprises a spring plate 8 which is of annular or disk-shaped design and runs around the damper tube 2. The spring plate 8 serves as a stop of a helical spring 9, the coils of which run around the damper tube 2. As an alternative thereto, the spring plate 8 can serve as a stop of a pneumatic spring (not illustrated in FIG. 1). The spring plate 8 is fastened via a securing element 10 which connects the spring plate 8 to the damper tube 2 in a form-fitting manner in the direction of the longitudinal axis 3 and also via a frictional press-fit connection. The securing element 10 can be, for example, a securing ring or a snap ring. The securing element 10 is arranged in a groove 11 which is molded into the outer surface of the damper tube 2 and encircles the damper tube 2 annularly.

[0034] FIG. 2A shows an enlarged detailed view of that region of the device which is denoted by II in FIG. 1, during a first production step. In particular, the connecting region between the damper tube 2 and the spring plate 8 is illustrated in the enlarged view. Those regions of the device which have already been described in conjunction with FIG. 1 are provided with corresponding reference signs in FIG. 2A. It can be seen in FIG. 2A that the damper tube 2 has a cylindrical outer surface with an outside diameter D2a and that the spring plate 8 has a cylindrical inner surface with an inside diameter D8i, wherein, in the production step shown in FIG. 2A, the outside diameter D2a of the damper tube 2 is smaller than the inside diameter D8i of the spring plate 8.

[0035] This has the consequence that the spring plate 8 can be pushed loosely onto the damper tube 2. The encircling groove 11 is molded into the damper tube 2 from the outside and serves as a seat for the securing element 10. In order to form a form-fitting connection, the securing element 10 has an inside diameter D10i and an outside diameter D10a, wherein the inside diameter D10i of the securing element 10 is smaller than the outside diameter D2a of the damper tube 2, and wherein the outside diameter D10a of the securing element 10 is greater than the outside diameter D2a of the damper tube 2. In the case of the production step shown in FIG. 2A, the inside diameter D10a of the securing element 10 corresponds to the outside diameter D11a of the groove 11. The spring plate has an encircling step 12 on its inner side. The step 12 has an inside diameter D12i which, in the production step shown in FIG. 2A, is greater than the outside diameter D10a of the securing element 10. The spring plate 8 can thereby be pushed loosely onto the securing element 10.

[0036] FIG. 2B illustrates an enlarged detailed view of that region of the device 1 which is denoted by II in FIG. 1, during a second production step. Those regions of the device 1 which have already been described in conjunction with FIG. 1 or FIG. 2A are also provided with corresponding reference signs in FIG. 2B. In contrast to the first production step (FIG. 2A), in the second production step (FIG. 2B), two annular tools 13 are pushed onto the damper tube 2 on both sides of the spring plate 8. The tools 13 have projections 14 which are arranged on that side of the respective tool 13 which is assigned to the spring plate 8. The two tools 13 are moved toward each other in the axial direction—i.e. along the longitudinal axis 3—and in this case plastically deform certain regions of the spring plate 8. The direction of movement of the tools 13 is illustrated schematically in FIG. 2B by means of arrows.

[0037] FIG. 2C finally shows an enlarged detailed view of that region of the device 1 which is denoted by II in FIG. 1, after production has finished. Also in FIG. 2C, those regions of the device 1 which have already been described in conjunction with FIG. 1 to FIG. 2B are provided with corresponding reference signs. FIG. 2C shows a state in which the spring plate 8 has been plastically deformed by the tools 13, and the tools 13 have already been pulled off again from the damper tube 2. Clearly visible is a plastic deformation of the spring plate 8, which results in the inside diameter D8i′ of the spring plate 8 having been reduced in size and now corresponding to the outside diameter D2a of the damper tube 2. A radial relative movement between the spring plate 8 and the damper tube 2 is therefore no longer possible. The plastic deformation of the spring plate 8 also results in the inside diameter D12i′ of the step 12 having been reduced in size and now corresponding to the outside diameter D10a of the securing element 10. Also, a radial relative movement between the spring plate 8 and the securing element 10 is therefore no longer possible. Frictional connections arise at the contact surface between the spring plate 8—in particular its step 12—and the securing element 10, and also at the contact surface between the spring plate 8 and the damper tube 2, because of the friction.

[0038] The variant of the device 1 described in FIG. 1 to FIG. 2C is a single-tube damper. However, the described features, in particular the connection between the spring plate 8 and the damper tube 2, can also be transferred to other designs of shock absorbers, in particular to two-tube dampers.

LIST OF REFERENCE SIGNS

[0039] 1: Device for damping vibrations [0040] 2: Damper tube [0041] 3: Longitudinal axis (of the damper tube 2) [0042] 4: Piston rod [0043] 5: Piston [0044] 6: Piston valve [0045] 7: Seal [0046] 8: Spring plate [0047] 9: Helical spring [0048] 10: Securing element [0049] 11: Groove [0050] 12: Step [0051] 13: Tool [0052] 14: Projection [0053] D2a: Outside diameter (of the damper tube 2) [0054] D8i, D8i′: Inside diameter (of the spring plate 8) [0055] D10a: Outside diameter (of the securing element 10) [0056] D10i: Inside diameter (of the securing element 10) [0057] D11a: Outside diameter (of the groove 11) [0058] D12i, D12i′: Inside diameter (of the step 12)