Anti-lock hydraulic brake system

Claim 1

An anti-lock hydraulic brake system for motor vehicles having vehicle wheels with wheel brakes with a pedal-actuated hydraulic brake power booster (3) having a booster chamber, with each of two hydraulically isolated static brake circuits connected to a separate working chamber of a tandem master cylinder, with each of two fluid inlet chambers of said master cylinder connected to one of said working chambers via a valve means, and with an auxiliary-pressure supply system (4, 5), wherein in the event of slip control pressure fluid is dynamically introducible into the static brake circuits by way of the booster chamber of the brake power booster, electromagnetically actuatable multi-directional control valves, said fluid inlet chambers, said valve means, and said working chambers, with inlet and outlet valves arranged in the pressure fluid paths leading from the wheel brakes to a brake pressure generator (1) and a pressure compensating reservoir, with a positioning device connected to the pedal for limiting the pedal travel and returning the pedal in the event of a control action and with wheel sensors and electronic switching circuits for the logical linkage and processing of sensor signals and for the generation of electric brake pressure control signals as a function of the rotational behavior of at least one wheel, and including pressure-controlled switches and monitoring switching circuits, wherein the front wheel brakes (7, 8) and the rear wheel brakes (9, 10) are respectively connected to one of the two static brake circuits (I, II), wherein the pressure fluid out of said auxiliary-pressure supply system (4, 5) and said brake power booster (3) is delivered into the two static brake circuits (I, II) from said booster chamber of said brake power booster (3) respectively by way of hydraulically isolated circuits having said multi-directional control valves (31, 32) respectively inserted therein which are switchable independently of each other, wherein the multi-directional control valves, in their inoperative positions, each connect the associated fluid inlet chamber with a pressure compensating reservoir, and, after having been switched over, hydraulically connect said fluid inlet chamber with the booster chamber, and wherein the positioning device (42) is connected to the rear wheel brake circuit (I) and is responsive to the multi-directional control valve (31) controlling the dynamic flow into the static brake circuit of the rear wheel brakes to translate said pedal toward its returned position.