Abstract: The invention relates to a hydraulic power steering system for motor vehicles, in the case of which the manual steering wheel is normally connected only by way of a control system with respect to the drive with a servomotor operating the steered vehicle wheels. In the event of a malfunctioning of the control system, a hydraulic forced coupling is automatically established between the servomotor and a hydraulic delivery unit which is constantly forcibly coupled with the steering handle, in order to form a "hydraulic linkage".

Abstract: A vehicle steering system has an electronic control system for coupling a steering device and the steered wheels of the vehicle, with the steering angle setpoint signal passing though a filter before a setpoint/actual value comparison is made. The filter passes essentially only those frequencies below an adjustable transition frequency. A switch is made to a low transition frequency when there is to be a direct translation between the steering device and the steered wheels of the vehicle.

Abstract: A steering apparatus includes a user-actuable steering-angle input device with an associated steering shaft, a steering-angle setting device coupled nonmechanically to the steering-angle input device and a reaction torque device which is coupled to the steering shaft. The reaction torque device produces a reaction torque mechanically and has at least one element which can be deflected elastically in a linear manner and is coupled to the mechanism by a driver unit acting axle steering shaft. In certain embodiments, a steering-shaft pinion and a rack which is coupled to the latter serves as a piston rod for at least one piston that can be deflected elastically in a linear manner. The at least one piston is guided in axially moveable fashion in a cylinder and, together with the piston rod, forms the driver unit.

Abstract: A control motor is provided which steers the vehicle wheels via a steering gear and a hydraulic servo motor is operatively connected to the steered vehicle wheels for supporting the control motor in following the control movements of a steering means operated by a vehicle operator, a servo valve arrangement is provided which controls hydraulic fluid admission to the hydraulic servo motor such that hydraulic fluid is admitted to the hydraulic servo motor only when the steering forces transmitted through the steering gear exceed a predetermined threshold value so that the vehicle wheels are steered by the control motor only when the forces transmitted through the steering gear are below the threshold value.

Abstract: A steering system for non-track vehicles, and a method of controlling a steering transmission ratio of a non-track vehicle, in which the steering transmission ratio between the adjusting paths of the steering handle and the steered wheels is changed corresponding to a characteristic diagram as a function of the driving speed as well as of the adjusting paths of the steering handle or the steered wheels.

Abstract: A hydraulic power steering system is provided in which a manual steering device and the steering vehicle wheels are normally coupled only by way of a control path with a desired-value generator operated by the manual steering device and an actual-value generator operated by the steering vehicle wheels. For controlling a hydraulic servomotor used for the steering operation of the steering vehicle wheels, a servo valve arrangement is operated by a desired-value/actual-value comparison. Only when there is a disturbance in the control path, will a hydraulic forced coupling take place between the manual steering device and the steering vehicle wheels.

Abstract: In a hydraulic power steering for motor vehicles having a steering control element, a position setting unit connected to the steering control element, a control motor connected to the position setting unit by way of a control circuit and a servo valve having control parts which are supported so as to be rotatable relative to each other but operatively interconnected by spring means retaining them in a central open position relative to each other, one of the control parts is operatively connected to the control motor and the other is connected to a steering gear mechanism associated with the steered wheels of the motor vehicle, and a hydraulic servomotor is associated with the vehicle wheel steering mechanism and hydraulically connected to the servo valve to receive hydraulic fluid therefrom depending on the relative rotary positions of the servo valve control parts.

Abstract: In a reaction simulator for a control system, particularly a vehicle steering system, including a control handle, particularly a steering wheel, for providing a master set point value for a slave control structure, particularly the operating mechanism of a vehicle steering system, the reaction simulator comprises a return spring arrangement biasing the handle into a rest position and force generating means for applying forces to the handle for simulating direct coupling of the handle and the slave control structure.