Patent ID: 6186602
Filing Date: 2001-02-13
Classification: B60T

Abstract:
A hydraulic brake system for a vehicle comprising wheel brakes for four wheels, in which the wheels are distributed on a first and a second vehicle axle, comprising an external hydraulic energy source, and has electrically controllable service brake valve devices disposed between said energy source and the wheels, a first braking power transmitter (38) that is actuated by a brake pedal, for carrying out service brake operations by operation of the service brake valve devices, a dual-circuit master cylinder, said master cylinder is actuated by the brake pedal and is intended for carrying out an auxiliary brake operation by muscle-powered energy via said brake pedal, wherein between the master cylinder and wheel brakes that are supplied from said master cylinder, a normally open operation mode reversing valve (17, 18) is disposed in each brake circuit, said reversing valve is switched into a closed position for the service brake operation, and wherein at least the service brake valve devices are controlled by a controlling and regulating device, a cylinder/piston device (52, 53) is interposed between the wheel brakes (5, 6) of the vehicle axle that is designed for a greater braking contribution to the vehicle braking and the associated, electrically controllable service brake valve devices (27, 28), and that the wheel brakes (5, 6) designed for the greater braking contribution to the vehicle braking are connected to the operation mode reversing valves (17, 18) associated with the two brake circuits of the master cylinder 9, a normally closed volume diversion valve (63, 64) is connected to the wheel brakes (5, 6) which are connected to the cylinder/piston device (52, 53), that said volume diversion valves (63, 64) are connected to a reservoir (14) of the external hydraulic energy source (19) and are opened by the controlling and regulating device (37) in the event that a brake pressure reduction that is controlled by service brake valves (27, 28) or a wheel brake slip reduction proves to be insufficient.