Abstract: The invention relates to a steering device for vehicles with a double-acting hydraulic working cylinder, which is divided into two working chambers by a piston, which is displaceably mounted in the working cylinder, to pivot at least one vehicle wheel, and a pressurizing means device producing a volume flow of a hydraulic medium, the hydraulic medium being supplied to a rotary slide valve, which supplies the volume flow, depending on the rotary slide valve position, to the working chambers of the double-acting hydraulic working cylinder or to a reservoir for the hydraulic medium, wherein when a certain pressure is exceeded in the feed line to the rotary slide valve, a pressure relief valve guides at least a part of the total volume flow of the hydraulic medium past the rotary slide valve in particular to the reservoir.

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: This invention relates to a servo valve which is constructed in the manner of a slide valve and particularly in the manner of a rotary slide valve. For changing the control characteristics the width of control gaps can be changed which exists in a normal or starting position. For this purpose, it is preferably provided that the control edges of the control gaps are aligned at least partially diagonally to the direction of the control strokes and the sliding part as well as the counter sliding part are completely or partially adjustable relative to one another transversely with respect to the direction of the control strokes.

Abstract: A device for the parameter-dependent control of a reaction force at an operating element, in particular a steering wheel of a motor vehicle, of a hydraulic power steering system. In this case, a parameter-dependent additional force is generated by an electric motor in addition to a hydraulically generated servo positioning force.

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.

Abstract: A hydraulic feedback control for hydraulic power steering systems having first and second shaft sections rotatable relative to one another within limits, and whose relative rotation controls a servo valve system. At least one compressor working chamber is provided in the form of a piston working chamber. A piston is arranged in the piston working chamber, and is displaceable therein and separate from the first shaft section. The piston is tensioned by a pressure in a piston working chamber against a spring engaged with the first shaft section. A maximum possible displacement travel of the piston relative to the second shaft section is limited by a stop mounted thereon. The feedback control is designed so that with limited frictional losses, controllable torques can be produced which counteract the relative rotation between the shaft sections.

Abstract: The invention relates to the control of a servo valve, in particular in a power steering system of a motor vehicle. Of two valve control parts which are coupled to one another with torsional elasticity by a torsion bar, one is connected merely non-positively to the assigned end of the torsion bar or to a part, which is arranged securely against rotation at the said end, in order to allow an adjustment while overcoming the non-positive engagement.

Abstract: A hydraulic power steering system has a servo valve which is arranged between the delivery and suction side of a hydraulic pump. The servo valve is open in the central or normal position and controls the pressure to at least one connection of a hydraulic servomotor. When an operating element of the power steering system is actuated, the servomotor serves to generate a servo positioning force which facilitates the adjustment of the operating element. The hydraulic pump has a drive which can be switched-off, or can be switched over to an extremely low capacity or standby operation, when no servo positioning force is required.

Abstract: A servo-assisted rack-and-pinion steering system has a helical-toothed rack and a helical-toothed pinion cooperating therewith. On the transmission of forces between the pinion and the rack, a torque relative to the longitudinal axis of the rack acts on the rack. The resulting rotation of the rack is utilized to control the servomotor via a lever arrangement.