Patent ID: 7726451
Filing Date: 2010-06-01
Classification: F16F

Abstract:
1. A vibration damper with an amplitude-selective damping force, comprising: a damping medium-filled cylinder and a piston rod axially movably guided in said cylinder and carrying a piston arrangement which divides said cylinder into a first working space on one axial side of said piston arrangement and a second working space on the opposing axial side of said piston arrangement; an axially movable switching ring arranged on said piston arrangement for axial movement between two stop surfaces on said piston arrangement, said switching ring controlling a flow connection between said first and second working spaces in response to an amplitude of movement of said piston rod, said flow connection being defined by said piston arrangement and said cylinder, said piston arrangement having a working surface defining a pilot opening cross section to said flow connection when said switching ring is positioned against one of said stop surfaces, said piston arrangement further defining a bypass channel arranged parallel to said flow connection and having at least two connecting openings to said flow connection, at least one of said two connecting openings being arranged upstream of one of said stop surfaces in each flow direction, said piston arrangement comprises a spacer sleeve defining said bypass channel, wherein an outside surface of said spacer sleeve defines a longitudinal profile allowing a flow to pass between said switching ring and said spacer sleeve; and a check valve arrangement separating said flow connection from said bypass channel in each of said flow directions, said check valve arrangement comprising two check valves which close in opposing directions.