Abstract: A reaction arrangement on a hydraulic servo-valve arrangement which is designed in the manner of a rotary-slide arrangement, with a rotary slide and with a control bush coaxially surrounding the rotary slide and rotatable relative to the latter, in particular for power steering systems of motor vehicles. Arranged on a shaft part located on the rotary-slide side are axial V-grooves, into which reaction bodies can be pressed with controllable hydraulic pressure. The reaction bodies are guided radially on a bush portion connected fixedly in terms of rotation to the control bush.

Abstract: In a hydraulic power steering for a motor vehicle with a hydraulic servomotor and a servovalve arrangement in communication with opposite servomotor actuating chambers by way of separate communication conduits through which the actuating chambers can be pressurized or depressurized for the operation of the servomotor depending on a force applied by an operator to a steering means, the communication conduits include valve arrangements permitting, when they are open, the release of hydraulic fluid from the actuating chambers but blocking the release of hydraulic fluid when they are closed thereby hydraulically locking the power steering.