Pressure modulator arrangement for a boosting of brake force and for antilock control

A pressure modulator system for use with a statically operated, power-assisted, hydraulic brake sytem of a vehicle including brake pressure control device for providing a pedal pressure, a proportional control device for providing a proportional pressure which is proportional to and substantially greater than said pedal pressure, an auxiliary pressure source, a statically operated brake circuit and antilock control unit, said pressure modulator system comprising:

• a modulator housing;
• a modulator piston means in said modulator housing for defining a modulator output pressure space, which can be coupled to said brake circuit, from a first driving pressure space, into which said pedal pressure can be coupled to decrease said output pressure space, from a second driving pressure, space, into which said proportional pressure can be coupled to boost decreasing of said output pressure space, and from a counterpressure space into which an auxiliary pressure can be coupled to increase said output pressure space;
• and
• control valve means connectable to said brake pressure control device, said proportional control device, said auxiliary pressure source and said modulator housing for connecting said proportional pressure to said second driving space and relieving pressure in said counterpressure space in a normal braking position and for connecting said auxiliary pressure to said counterpressure space and relieving pressure from said second driving space in an antilocking position.