초록 ▼

A hydraulic dual-circuit brake system for a road vehicle with front-axle/rear-axle brake circuit division has a tandem main cylinder as a brake device. The primary output pressure space of the cylinders is associated with the front-axle brake circuit, and the secondary output pressure space of the c

A hydraulic dual-circuit brake system for a road vehicle with front-axle/rear-axle brake circuit division has a tandem main cylinder as a brake device. The primary output pressure space of the cylinders is associated with the front-axle brake circuit, and the secondary output pressure space of the cylinders is associated with the rear-axle brake circuit. A pressure modulator adjusts the front-axle/rear-axle braking force distribution in the direction of an approach to the, in each case, ideal braking force distribution, as a braking-pressure actuator for the rear-axle brake circuit. The pressure modulator has a drive pressure space, by the charging of which with the output pressure of an auxiliary pressure source under solenoid valve control, a braking pressure which can be coupled into the rear-wheel brakes can be built up in an output pressure space of the pressure modulator. This output pressure space is also connected to the output pressure space of the brake device provided for the rear-axle brake circuit. During normal braking action, the output pressure space of the pressure modulator is blocked off against the output pressure space of the brake device, and the pressure build-up in the rear-axle brake circuit is exclusively effected by the pressure modulator which is driven in the direction of a servo control for which a set point Ps correlated with the braking pressure in the front-axle circuit as ideal or almost ideal value is utilized as a reference variable.

대표청구항 ▼

A hydraulic dual-circuit brake system for a road vehicle, with a division of a front-axle brake circuit and a rear-axle brake circuit, comprising a braking-pressure generator having two output pressure spaces, each allocated to one of the two brake circuits, in which static pressure is built up prop

A hydraulic dual-circuit brake system for a road vehicle, with a division of a front-axle brake circuit and a rear-axle brake circuit, comprising a braking-pressure generator having two output pressure spaces, each allocated to one of the two brake circuits, in which static pressure is built up proportionally to an actuating force; and electro-hydraulic open-loop braking-pressure control device which, in at least one of closed-loop control phases of a closed-loop antiblocking and of a closed-loop drive slip control device with which the vehicle is also equipped, determines control of braking-pressure changing and braking-pressure holding phases, so as, in normal braking operation, to convey an adjustment of front-axle/rear-axle braking force distribution to an extent which at least approximately corresponds to an ideal braking force distribution both in a partial and in a full-braking range, the open-loop control device comprising sensors operatively arranged to generate electric output signals characteristic of the braking pressures and coupled into the brake circuits, an electronic open-loop control stage to which the output signals of the sensors are supplied as inputs to generate from a comparative processing of actual values, represented by the output signals of the sensors, of the braking force distribution with set points charcteristic of ideal braking force distribution, which are determined from vehicle-specific data in combination with data characteristic of ideal braking force distribution determined from vehicle-specific data in combination with data characteristic of at least one of an operating situation and a loading situation of the vehicle, electrical control signals required for driving the braking-pressure actuator, and a pressure modulator having an output pressure space movably delimited in a pressure-tight manner with respect to the drive pressure space by a piston and which is operatively connected to an associated brake circuit and also to an output pressure space of the braking-pressure generator, the output pressure space of the modulator being blocked off against the output pressure space of the braking-pressure generator with which the outlet pressure space of the braking-pressure actuator pressure modulator is associated in normal braking operation, and pressure build-up in one of the front-axle brake circuit and rear-axle brake circuit connected to the output pressure space of the pressure modulator is effected by valve-control pressure charging of the drive pressure space with output pressure of an auxiliary pressure source, the pressure build-up in the one brake circuit connected to the output pressure space of the pressure modulator being implemented by a servo control, for which a set point for the braking pressure in the brake circuit connected to the pressure modulator, correlated with the braking pressure in the other of the two brake circuits is an ideal value or approximately ideal value is utilized as a reference variable.