Zf Friedrichshafen Ag

Andreas Föster

Steffen Heyn

Heinz-Joachim Gilsdorf

Thomas Kutsche

Alfred Wirth

An adjustable damping valve device for a vibration damper includes a housing with an axially movable valve body. The valve body has in the direction of a valve seat surface a pressure-loaded surface Awhich is operative in the lift direction of the valve body and a surface Awhich is loaded by pressure in the closing direction, wherein a resultant force comprising a force of at least one valve spring and an actuating force of an actuator acts on the valve body, and wherein an additional surface Aof the valve body is pressure loaded by damping medium in closing direction of the valve body. The damping valve device has an emergency operation valve by means of which a pressure level can be at least indirectly adjusted in a control space for an emergency operation. The emergency operation valve is operative only in one flow direction.

Adjustable damping valve device having an emergency operation valve

Actuator which can be actuated electromagnetically includes a coil, a magnetically conductive actuator sleeve being fixed in the magnetic field thereof. The magnetic field passes radially from the actuator sleeve to an axially movable armature and passes axially in the area of a pole plane from the armature to a return member which is stationary with respect to the actuator and, in so doing, generates a magnetic force which displaces the armature. The actuator sleeve for the magnetic flux of the coil has at least two functionally parallel passage areas having different cross sections for receiving the armature which has a conducting profile complementary to the actuator sleeve.

Actuator which can be actuated electromagnetically, particularly for an adjustable damping valve of a vibration damper

The vibration damper with an adjustable damping force includes a cylinder filled with a damping medium, a piston rod axially movable in the cylinder and carrying a piston which divides the cylinder into a first working space on the piston rod side and a second working space on the side away from the piston rod, a first adjustable damping valve which is connected to at least one of the two working spaces by means of a fluid connection, at least one second valve which is connected hydraulically in parallel to the first adjustable damping valve, and a third damping valve arranged in series to and upstream from both the first and second valves, the third damping valve moving in a closing direction as a function of a flow velocity of the damping medium through the third damping valve.

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Schweinfurt, Germany

Andreas Föster