Vibration damper

Abstract

Vibration damper comprising a cylinder in which a piston rod is guided with freedom of axial movement, where the piston rod cooperates with a piston arrangement comprising a first, stationary piston and at least one additional piston, which is supported on the piston rod with freedom of axial movement against the elastic force of at least one restoring spring, where the cylinder is divided by the stationary piston and by the minimum of one axially movable piston into a working space on the side of the piston facing the piston rod, a working space on the side of the piston facing away from the piston rod, and a working space between the two pistons, where valve-equipped through-openings control a connection between the working spaces, and where the axial movement of the minimum of one axially movable piston is limited by a hydraulic pressure stop.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional diagram of the piston arrangement mounted on the piston rod; and

FIG. 2 shows an exploded view of the arrangement according to FIG. 1.

Claims

1. A vibration damper comprising: a cylinder;a piston rod guided with freedom of axial movement in the cylinder;a first piston fixed to the piston rod so that the first piston is stationary with respect to the piston rod, said first piston bounding a first working space facing away from the piston rod;a second piston mounted on the piston rod with freedom to move axially with respect to the first piston against the force of at least one restoring spring, said second piston bounding a second working space facing the piston rod and an intermediate working space between the pistons;at least two openings equipped with non-return valves in each of said pistons, said openings connecting said working spaces; anda hydraulic pressure stop limiting the movement of said second piston in at least one direction with respect to said first piston.

2. The vibration damper of claim 1 wherein the pressure stop comprises a displacer sleeve and a stop cup, said displacer sleeve being received in said stop cup to limit movement of said second piston with respect to said first piston.

3. The vibration damper of claim 2 further comprising a spring collar fixed to the second piston, one of said displacer sleeve and said stop cup being fixed to a side of said collar facing away from said second piston.

4. The vibration damper of claim 2 further comprising a spring collar fixed to the piston rod and facing the second piston, one of said displacer sleeve and said stop cup being fixed to a side of said collar facing said second piston.

5. The vibration damper of claim 2 wherein the displacer sleeve has a cross-section which increases as it enters the stop cup, thereby increasing throttling of hydraulic fluid as the sleeve enters the cup.

6. The vibration damper of claim 5 wherein the stop cup has an inner wall and the sleeve has an outer surface which define a damping cross-section therebetween, said damping cross-section diminishing to a residual damping cross-section as said sleeve enters the stop cup.

7. The vibration damper of claim 2 wherein the restoring spring limits an annular space between the restoring spring and the piston rod, the displacer sleeve being located inside the annular space.

8. The vibration damper of claim 2 wherein the displacer sleeve comes to rest axially in the stop cup before the restoring spring has used up all of its elastic travel.

9. The vibration damper of claim 2 wherein one of said displacer sleeve and said stop cup is made of plastic.

10. The vibration damper of claim 2 wherein the stop cup has a displacer space which is bounded radially by a wall of the stop cup and a lateral surface of the piston rod.