Abstract

Adjustable shock absorber, particularly for motor vehicles, which includes a cylinder containing damping fluid, an axially-movable piston rod which projects in a sealed manner into the cylinder, and a piston fastened to the rod and dividing the cylinder chamber into two working chambers interconnected by at least one passage which produces a damping force, the effective cross section of which can be adjusted by means of a throttle valve. The bypass includes a flexible membrane enclosed in a chamber such that on the one side of the membrane, there is at least one inflow passageway and at least one outflow passageway of the passage which can be sealed off from one another by the membrane, a control edge (or valve seat) which interacts with the membrane, and on the other side of the membrane, a control chamber carrying a control bypass flow and sealed off from the passage.