Abstract: A hydraulic anti-lock brake system is disclosed in which the pressure in the wheel brakes can be regulated by means of an inlet valve and an outlet valve in response to the wheel rotational pattern. The wheel brake is supplied with pressure fluid out of the pumps through the inlet valve, and pressurized fluid is taken therefrom through the outlet valve. A differential pressure limiter (18) in front of the inlet valve (15) limits the difference in pressure allowed to build up across the inlet valve by closing a valve until a sufficient pressure build up occurs on the wheel brake. This considerably decreases the noise developed during valve operation. A pressure relief valve (30) insures that an evenly high pressure build-up takes place when the inlet valve (15) is closed by opening when a predetermined pressure difference develops across the inlet valve to allow a higher wheel brake pressure to equalize with the pressure upstream from the inlet valve.

Abstract: The pressure in the wheel brake of the system is controlled by an inlet valve 15 and an outlet valve 17 activated in response to the system controls. Fluid pressure from the pumps 13, is supplied to the wheel brake through the inlet valve 15, and discharged from the wheel brake through the outlet valve 17. By inserting a differential pressure limiter valve ahead of the inlet valve 15, the noise generated by the inlet valve is substantially reduced. A valve body 45 carries both the limiter valve seat and a discharge check valve seat, and respective closure balls 61, 62.

Abstract: Hydraulic brake systems are known wherein, for the purpose of brake control, a counterforce is built up in the booster (60) for actuation of the master brake cylinder which results in unloading the master brake cylinder. What is disadvantageous in the known system is that this counterforce also resets the pedal (pedal piston 3) so that vehement pedal movements will result from the control action. Therefore, our present invention suggests to interpose a transmission device (3, 4, 5, 6, 7) between the pedal and the actuator (booster) enabling to decouple actuator and pedal.