In an auxiliary power assisted master cylinder arrangement for a vehicle brake system to generate a controlled brake pressure in associated wheel brake cylinders, there is provided a brake valve with a preceding servo travel simulator to effect a control of the wheel brake cylinders of a vehicle. In one construction of the arrangement, there is interposed between two master cylinder units a pedal-operable device including mechanical cross links connecting with the master cylinder units as well as another cross link connecting with the brake valve. The brake valve is movable into engagement with the servo travel simulator, while the pedal-operable device, under normal braking conditions, is acted upon by the controlled pressure from an auxiliary power source in opposition to the pedal pressure and includes a lock providing for interlocking of all mechanical links in the event of a failure of auxiliary power. In another construction, each master cylinder unit is preceded by a second lock which is normally released with auxiliary power available and, in the event of a failure of the auxiliary power, couples the master cylinder units with the associated cross links at least in the direction of pedal operation. The present invention is advantageously employed as a brake slip control apparatus.

A method and a multi-circuit brake booster for feeding back disruptions of any arbitrary kind, even of an associated anti-skid brake system, to a then-changed brake pedal characteristic, the influence on the brake valve triggering being effected via a travel simulator device. The transmitting member in the travel simulator device is a travel simulator spring enabling a predetermined idle pedal travel, and this spring responds whenever, in response to an arbitrarily generated disruption signal, a lockable storage element assumes its other position and mechanically engages a transmitting member in the chain from brake pedal actuation to brake valve slide actuation in an arresting manner. Upon reaching a predetermined amount of biasing, as a result of the further compression of the travel simulator spring, the opening of the brake valve then takes place abruptly, with a corresponding increase in brake pressure and a corresponding increase in vehicle deceleration.

A brake booster, combined with an anti-skid apparatus for a master brake cylinder. The brake booster is controlled by a brake valve and has a first booster piston displaceable by a brake pedal via a tappet for emergency braking and hydraulically pressurizable for braking with brake boosting, and a second booster pinion, which is only hydraulically displaceable. With normal braking, both booster pistons operate simultaneously. In case of skidding the first booster piston is hydraulically fixed in its operative position during a first, low brake pressure reduction and the second booster piston is relieved of boost pressure and performs reductions in brake pressure. If these are not sufficient, the first booster piston is also displaced in the direction of its initial position. Whereby the first booster piston pressures against the tappet via a spring mounted between it and the tappet which, in turn, acts on the brake pedal. Dependent on the magnitude of the reduction in the brake pressure during the second brake pressure reduction, the displacements of the first booster piston are more or less and act via the spring on the brake pedal with greater or lesser force.

An auxiliary-energy-operable hydraulic brake system for automotive vehicles, in which a valve device connected to a pressure medium source and to an unpressurized reservoir and controlling an actuating pressure is operable by an actuating element which, irrespective of its direction of actuation, may be pressurized by a reaction force depending on the actuating pressure. The valve device is operable electromagnetically and controllable by an electric switching device connected with the actuating element.

A braking pressure generating apparatus for a vehicle includes a hydraulic pressure generator for generating and outputting a power pressure irrespective of an operation of a brake pedal, and an input member connected with the brake pedal. A regulation valve is disposed coaxially with the input member to regulate the power pressure outputted from the hydraulic pressure generator to a predetermined pressure corresponding to the braking operation force of the brake pedal and output the predetermined pressure. The regulation valve includes a body and a valve portion movably disposed in the body. A force distribution device is disposed between the input member and the regulation valve to the distribute braking operation force applied to the input member the valve portion and the body of the regulation valve.