Patent ID: 6119831
Filing Date: 2000-09-19
Classification: F16F

Abstract:
A controllable vibration damper for motor vehicles, comprising:a cylinder having two ends and containing a damping fluid;a piston rod sealingly entering said cylinder through one of said two ends and axially movable with respect to said cylinder;a damping piston connected to an end of said piston rod and dividing said cylinder into first and second working spaces;a damping valve mounted in said damping piston having an axially displaceable valve body and a valve housing having a first valve seat;a damping passage passing through said damping valve;a precontrolling means arranged in an actuation chamber in said valve housing and comprising an axially movable first valve element mounted within said valve housing, a drive element axially displaceably arranged in said valve housing, a spring element arranged between said first valve body and said drive element for urging said first valve element against a second valve seat arranged on said valve body, and an actuator for axially displacing said drive element, said first valve element communicating with said second working space through a first passage having a prerestricting element so that said first valve element applies a pressure to said spring element in response to a pressure in said second working space, said valve body comprising a second passage connecting said actuation chamber and said first working space, wherein a cross-section of an area between said first valve element and said second valve seat controls a flow of said damping fluid through said damping passage when said vibration damper is acted on in a first direction; andsaid valve body directly axially displaceable by a pressure in said first working space when said vibration damper is acted on in a second direction for controlling a flow of said damping fluid through said damping passage when said vibration damper is acted on in said second direction.