Patent ID: 8061786

Claim:
A brake system for motor vehicles comprising a master cylinder ( 1 ), a first piston ( 2 ) which is coupled to a brake pedal ( 3 ) by way of a push rod ( 28 ) that transmits actuating forces, a second piston ( 4 ) for actuating the master cylinder ( 1 ), a third piston ( 5 ) which is configured to be actuated by the first piston ( 2 ) and to be moved into a force-transmitting connection with the second piston ( 4 ), at least one elastic element ( 6 , 7 ) forming a pedal travel simulator, a coupling element for coupling the movements of the first and the third pistons, said coupling element being activated depending on the displacement travel of the third piston ( 5 ) in a housing ( 20 ), a space ( 11 ) between the second ( 4 ) and the third pistons ( 5 ) to which hydraulic pressure is applicable, and pressurization of the space ( 11 ) loads the second and third pistons ( 4 , 5 ) in opposite direction, as well as a pressure-supplying module ( 13 ), which enables both filling of the space ( 11 ) with pressure fluid as well as its evacuation, wherein a fourth piston ( 8 ) is arranged between the first piston ( 2 ) and the third piston ( 5 ) and delimits a hydraulic compartment ( 9 ) in interaction with the third piston ( 5 ), wherein said compartment has a hydraulic connection to a pressure fluid supply tank ( 31 ) closable by a brake pedal application and wherein said compartment is configured to allow a hydraulic pressure build-up by actuating forces, and wherein the hydraulic pressure introduced into the compartment ( 9 ) allows actuating a valve assembly ( 10 ), which varies the pressure introduced into the space ( 11 ).