Controllable or regulatable hydraulic shock absorber

A controllable hydraulic shock absorber, comprising:

• a piston;
• first and second working chambers divided from one another via said piston;
• a damping-control valve arrangement connecting said first and second chambers for exchanging hydraulic medium during stroke movements of said piston, said damping-control valve arrangement including a closing member, controlled via an electromagnet arrangement, which, when stressed into a closing position via a spring element, opens an orifice cross-section, said damping-control valve arrangement depending on the pressure difference between said first and second working chambers and on the force of said electromagnet arrangement and including an armature arrangement located between said closing member and said spring element, said electromagnet arrangement being a proportional magnet such that the adjusting force depends substantially solely on the intensity of electrical current passing through said electromagnet arrangement;
• wherein a force proportional valve serves as said damping-control valve arrangement, the damping force being substantially independent of the piston stroke speed and wherein said armature arrangement is loaded in both a direction to strengthen and weaken the closing force of said closing member dependent upon the passage of current through said electromagnet arrangement;
• and
• wherein said spring element is dimensioned to provide an optimal basic damping for hard and weak damping conditions corresponding to that of a non-controllable hydraulic shock absorber when said electromagnet arrangement is inoperative.