1. Field of the Invention
This invention relates to a vibration damper, in particular a single-tube vibration damper, comprising a cylinder which is closed on the end by a piston rod guide which centers an axially movable piston rod with a piston, whereby the piston with its damping valves divides the cylinder into an upper and a lower work chamber, and a decompression stop in the form of a compression spring with a round wire cross section which is located in the top work chamber.
2. Background Information
A similar vibration damper of the prior art is disclosed, for example, in German Patent No. 26 55 705. On this shock absorber of the prior art, a spring is used as a mechanical compression stop, and is located in an upper work chamber which is formed by the cylinder and the piston rod. In the embodiment illustrated in FIGS. 1 and 2 of the prior art, a round wire spring is used which is designed so that it has some play or clearance with respect to the cylinder and the piston rod. The spring is held by means of a damping ring which forms a friction fit with the cylinder. This design can only be used to a limited extent in single-tube dampers, since in single-tube dampers, the cross section of the annulus of the upper work chamber is particularly small. Fastening problems arise in particular if the stop is to be a decompression stop which has no hydraulic components, since it is impossible to use a damping ring to hold the spring. In the variant illustrated in FIGS. 3 and 4 of the prior art, a cornered or polygonal spring is used which interferes with the cylinder and thereby forms an interference fit, the friction force of which holds the spring in the cylinder. A cornered spring is significantly more expensive than a round wire spring, which means that cornered or polygonal springs are used only rarely.