Braking pressure modulator

A braking pressure modulator comprising a volume-receiving unit including a displacement member in a working chamber, said volume receiving unit hydraulically interposed between a master brake cylinder and a wheel brake cylinder of a brake system, said volume receiving unit adapted to be uncoupled form the master brake cylinder by a separating valve coupled to said volume-receiving unit which separating valve closes automatically when the displacement member moves from one end position in said working chamber where at said displacement member modulates the pressure in the working chamber and wheel brake cylinder, an actuator including an adjusting member that is coupled to the displacement member by a gear unit having a transmission characteristic driven by a piston and diaphragm assembly operatively connected thereto, said piston and diaphragm assembly responsive to a pressure difference across said piston and diaphragm to generate an adjusting force that is dependent on the difference in pressure wherein the transmission of the gear unit varies in such a manner that a defined adjusting force of the actuator will be generated by a predetermined value of said differential pressure and said gear unit urges the displacement member in the direction of its one end position to modulate said pressure, said gear unit adapted to provided that forces acting on the displacement member or urging the displacement member in a direction toward an end position opposite said one end position remain substantially in a condition of balance with the adjusting force irrespective of the position of the displacement member when the displacement member leaves its one end position and begins movement in the opposite direction upon a predetermined maximum pressure being attained in the working chamber with the separating valve closed.