End-stop control valves for providing progressive damping forces in vibration dampers

Abstract

An end-stop control valve can progressively add end-of-stroke damping resistance to complement the damping force provided by a main piston in a damper tube. The end-stop control valve may include a piston that is secured on a piston rod and selectively engages a catch piston, both of which are longitudinally movable within the damper tube. As the piston approaches the catch piston, an annular pocket of hydraulic fluid is created longitudinally and radially between the piston and the catch piston. As the piston continues to approach the catch piston, a cross-sectional area through which hydraulic fluid exits the pocket decreases, thereby gradually increasing the resistance of the end-stop control valve. In addition, a spring disc secured on the piston rod may contact a valve seat on the catch piston and provide resistance by elastically deforming in a longitudinal direction before the contact surfaces of the piston and catch piston engage.