Abstract: A master cylinder (10) for a hydraulic vehicle brake system has a housing (34) and a bore (36) which is disposed therein and in which a hollow cylindrical primary piston (38), which acts on a pressure chamber (40), is guided in a sealing and axially displaceable manner. An axially displaceable, hollow cylindrical auxiliary piston (42) is accommodated in the primary piston (38), into which piston (42) an actuating piston (46) projects, which piston (46) is adapted to be actuated by means of an input member (24), is is guided in a sealing and displaceable manner in the auxiliary piston (42) and is resiliently preloaded away from the latter at least during braking. The actuating piston (46) has a first hydraulically active diameter (D1) and the auxiliary piston (42) has a second hydraulically active diameter (D2). The auxiliary piston (42) is rigidly coupled to the actuating piston (46) after covering a determined distance against its resilient preload.

Abstract: Two chambers (12, 14) in a booster casing (10) are separated by a movable wall (16) which is connected to a valve housing (22). The housing contains a movable sealing member (60) with which a first valve seat (24), formed in the valve housing (22), and a second valve seat (32), formed on a movable valve closing member (30), are associated. The valve closing member (30) is guided for axial displacement on a piston (42) and designed as the armature of an electromagnet (40) which is arranged inside the valve housing (22) in such a way that, when energized, it moves the valve closing member (30) away from the sealing member (60) against the resistance of a valve spring (38). The piston (42) is guided for axial displacement in the valve housing (22) and serves to transmit actuating forces from an actuator member (44) to an output member (50).

Abstract: A brake actuator assembly for motor vehicles. A mounting plate (14) formed with a central hole (60) serves for fastening a pneumatic brake pressure booster (22) to the splashboard (10) of a motor vehicle. The brake pressure booster (22) includes a rear housing portion (50) formed with a rearwardly projecting tubular connecting piece (52) which is pushed from the front through the central hole (60) in the mounting plate (14) and through a central recess (70) presented in a stiffening plate (66) which abuts against the mounting plate (60) from the rear. In this manner the brake pressure booster (22) is centered with respect to the mounting plate (14) and the stiffening plate (66). The stiffening plate (66) is formed in one piece with support blocks (68) for a pedal arrangement (20) of the usual kind in motor vehicles.

Abstract: A method of determining the coefficient of adhesion between a roadway and the wheels of a motorcycle provides for retarding the rear wheel of the motorcycle more strongly than the front wheel for a predetermined period of time and for comparing the rotational speeds or the rotational retardations of the front and rear wheels. Furthermore, the sloping of the motorcycle is measured directly so as to determine both the longitudinal coefficient of adhesion and the lateral coefficient of adhesion from the sloping. The coefficients of adhesion thus obtained serve for adjustment of threshold values for anti-lock braking of the motorcycle.

Abstract: The invention relates to a motor vehicle braking system, comprising a brake pedal (P) to generate brake pressure in an hydraulic fluid, a brake pressure booster (12) operated by differential pressure and adapted to be actuated by a first valve (V.sub.1) which is pressurized mechanically by the brake pedal (P), and a first sensor (S.sub.1) to detect the pressure generated by the brake pedal. A second sensor (S.sub.R, S.sub.L) is provided to detect vehicle deceleration or rotational retardation of braked wheel, and a data processing unit serves to compare the data determined by the sensors (S.sub.1, S.sub.R, S.sub.L) and to generate a control signal in response to the result of the comparison for a second valve (V.sub.2) which is controllable electrically and by which a pressure difference is adjustable in the brake pressure booster (12).

Abstract: An antilock brake system comprises a valve (20) in the flow path of the hydraulic fluid between a master cylinder (10) and a brake cylinder (18). To obtain on braking without antilock control a rapid pressure buildup in the brake cylinder (18) and a throttled pressure buildup when braking with antilock control, a valve (20) is provided in the hydraulic connecting conduit (14, 14', 14") between the master and brake cylinders and comprises a floating piston (50) which is subjected on the one side to the pressure of the hydraulic fluid in the master cylinder (10) and on its other side to the pressure of the hydraulic fluid in the brake cylinder (18). The floating piston (50) controls the valve in such a manner that when the pressure in the master cylinder (10) is greater by a predetermined amount than the pressure in the brake cylinder (18) only a throttled flow through the valve (20) is possible.

Abstract: A differential pressure control valve comprises a plunger (36) which is displaceable in a housing (30) by an electromagnet (32). By way of a stop (52) a first spring (44) presses the valve seat (V.sub.S) into its inoperative position against a first seat ring (60). In moving toward the valve seat (V.sub.S) the plunger (36) is cushioned by a second spring (42) before or as it touches the valve seat. Very sensitive actuation of the valve is obtained by the fact that the first spring exerts somewhat greater pressure than the second one.

Abstract: In an anti-lock brake system (ABS) for a motorcycle the driving stabilty is improved by measuring the position of lateral inclination of the motorcycle and adjusting at least one threshold value for the anti-skid control in response to the measurement. In another embodiment the transverse acceleration of the motor cycle is measured and an ABS threshold value adjusted accordingly.

Abstract: In an anti-lock vehicle braking system the brake pressure acting at the controlled wheel is controlled in such a manner that the threshold value with respect to the rotational retardation of the wheel at the beginning of a lowering or raising of pressure is increased briefly, during a control cycle, by a constant amount (S.sub.H -S.sub.G) with respect to a threshold base value (S.sub.G) in order to avoid any undesired control operations caused especially by axle vibrations, pot holes, and the like. The threshold value is then decreased in response to the period of time of the pressure reduction in the preceding control cycle. The decreasing of the threshold value is carried on to values S.sub.T below the threshold base value and maintained for a given time interval (t.sub.x -t.sub.y).

Abstract: A brake circuit for a vehicle having selectively brakeable rear wheels comprises separate master cylinders each connected to one rear wheel brake and separately operable by means of foot pedals. The outputs of the master cylinders are connected to a control valve which in turn is connected to front wheel hydraulic brakes of the vehicle. When either of the pedals is depressed without depressing the other pedal the control valve is effective to isolate the front brakes from the pressurized rear brake circuit. However, when the brake pedals are linked together by a plate so that both rear brakes are operated together with control valve establishes a communication between the output of one master cylinder and the front brakes, thereby allowing four wheel braking.