Abstract: The hydraulic damper according to the invention has at least one restricted communication passage (47) between its two working chambers (8, 9) whose cross section is controlled by a viscous restriction valve (51) positioned via a control pressure of a fluid of a control damper with at least one secondary chamber (41, 42) delimited in a secondary cylinder (39) by a control piston (40), which cylinder and control piston are integrally attached, one to the main body (1), the other to the damping piston (4) of the damper, such that the damping law of the control fluid positioning said valve (51) is linked to the relative displacements of the main body (1) and damping piston (4).Application to the equipping of elastic-return struts with integral damping, in particular for helicopter rotors and blades. FIG. 2.

Abstract: A suspension for a set of two wheels of a vehicle comprises two arms oscillating about an axis X--X transverse with respect to the vehicle and each bearing a wheel, and dampers associated with said arms to counteract and damp the vertical movements of the wheels. The dampers comprise an assembly of two concentric tubes made of composite fiber-synthetic resin material coaxial to the transverse axis X--X of oscillation of the arms. The ends of the tubes are connected to each other and with one of the arms, and the outer tube of the assembly of tubes is connected to the chassis of the vehicle at at least one point close to the middle of its length.