Controllable hydraulic vibration absorber

A controllable hydraulic vibration absorber for automotive vehicles with a power cylinder defining an interior space sub-divided by a piston slidable by a piston rod into a first and a second power chamber, a connecting tube which is approximately positioned coaxially with said power cylinder and which Jointly with the power cylinder defines a connecting duct, a balancing chamber defined by one of an external balancing chamber and an external tube approximately positioned coaxially with the connecting tube and partly filled with oil and which is in connection with said first power chamber through said connecting duct and in connection with said second power chamber through a non-return valve, a switching valve which is subject to the pressure existing within said second power chamber and a controllable vibration absorber valve which affords variation of a vibration absorbing power, said non-return valve and said switching valve being both coaxial with said power cylinder and forming a valve assembly, said controllable vibration absorber valve being configured to include a seat valve to allow flow through said absorber valve in one direction only and operatively positioned between said connecting duct and said balancing chamber, said switching valve being inserted between said second power chamber and said connecting duct.