Patent ID: 6250416
Filing Date: 2001-06-26
Classification: B60R,B62D

Abstract:
Hydraulic power steering system witha steering wheel (1), alsosteerable vehicle wheels positively coupled to the latter for steering adjustment, anda double-acting hydrostatic servomotor (4) positively coupled to the steerable vehicle wheels and/or the steering handle,a hydraulic pressure-generating device (11, 13),a relatively pressureless hydraulic reservoir (12),a control-valve arrangement (7, 8) which has two parallel three-way pressure-reducing valves (7, 8) assigned in each case to one side or connecting line (5, 6) of the servomotor (4) and which makes it possible to connect both sides of the servomotor (4) to the pressure-generating device (11, 13),a sensor (16) for detecting forces or moments transmitted between the steering wheel(1) and the steerable vehicle wheels, and alsoan electronic control device (15) which is connected, on the input side, to the sensor (16) and which controls the control-valve arrangement (7, 8) as a function of the forces or moments transmitted between the steering wheel (1) and the steerable vehicle wheels, in such a way that the servomotor (4) generates a boosting force in order to reduce a manual force perceptible on the steering wheel (1), characterized in thatthe pressure-generating device (11, 13) has a hydraulic pressure accumulator (11),the three-way pressure-reducing valves (7, 8) are provided with a controllable motor-pressure desired value, andthe control-valve arrangement (7, 8) is controlled by controlling the motor-pressure desired values of the pressure-reducing valves (7, 8).