Hydraulic shock absorber with compression filtering

Abstract

The invention relates to a shock absorber (), in particular for a motor vehicle, which comprises: a cylinder () containing a hydraulic fluid; a main piston () actuated by a rod (), defining in the cylinder a first main chamber () and a second main chamber (), the second main chamber containing the rod; a hydraulic fluid vessel (); and a valve () placed in the flow of the hydraulic fluid between the first main chamber and the second main chamber or between the first main chamber and the vessel. The valve comprises a mobile gate () engaging with a seat (), a spring () tending to urge the gate against the seat thereof, and a mobile valve piston (), defining a first valve chamber () and a second valve chamber () in the valve, said mobile valve piston being capable of compressing the spring and closing the gate. The shock absorber also includes a control restriction () mounted in the flow of the hydraulic fluid from the first main chamber () during a compression movement, the control restriction being capable of generating a pressure difference acting on the respective surfaces of the mobile valve piston in a direction that tends to compress the spring during a compression movement and a means () for slowing the movement of the mobile valve piston ().