Brake system with slip control for automotive vehicles with a driven axle and a non-driven axle

Claim 1

A brake system including slip control and traction control for automotive vehicles having a driven axle and a non-driven axle, comprising: a master cylinder having a working chamber connected to a pressure medium storage/pressure compensation reservoir and also being connected to an inlet valve of a non-driven wheel brake via a first pressure supply line; an auxiliary pressure supply system, said supply system operating during brake slip control and traction slip control phases and connected via at least one non-return valve and a second pressure supply line to an inlet valve of a driven wheel brake; an outlet valve at each wheel brake connecting said brake to said reservoir; a control valve connected between the working chamber and the reservoir, said control valve being open when a master cylinder piston is in a rest position and being closed upon brake actuation when the auxiliary pressure supply system is not operating, said valve regulating a fluid pressure in the working chamber when the auxiliary pressure supply system is operating so as to maintain said regulated fluid pressure in proportion to a brake pedal force; and an additional multi-directional valve connecting the driven wheel brake inlet valve with the non-driven wheel brake inlet valve, said additional multi-directional valve being located in a line intersecting with said second pressure supply line between said supply system and the inlet valve of said driven wheel brake, control means being provided to control said additional multi-directional valve so that said additional multi-directional valve is closed during the traction slip control phase and is open at all other times so as to connect driven to non-driven wheel brake circuits; whereby fluid pressure in the working chamber as augmented by the auxiliary pressure supply system is applied to both driven and non-driven wheel brakes during normal braking and brake slip control phases, and fluid pressure from the auxiliary pressure supply system alone is applied to only the driven wheel brake during the traction slip control phase.