Patent ID: 7726438

Claim:
Hydraulic steering system for a vehicle having at least two steering cylinders, in which cylinder pistons are displaceable, the position and/or direction of motion of which in the steering cylinders fix the steering angle and/or steering direction of steerable vehicle wheels relative to a body of the vehicle, wherein each of the displaceable cylinder pistons divides the associated steering cylinder into in each case two pressure chambers and having an, in terms of the volumetric displacement, variable first hydraulic pump, a first port of which is connected, depending on the steering direction to one of the pressure chambers of the first steering cylinder and to one of the pressure chambers of the second steering cylinder, wherein a second port of the variable first hydraulic pump is connected in a closed circuit to the other pressure chamber of the first steering cylinder and to the other pressure chamber of the second steering cylinder, and wherein the first input port of a 4/3-way adjusting valve is connected to the high-pressure port of a feed pump, the second input port thereof is connected to a hydraulic tank, the first output port thereof is connected to a first adjusting pressure chamber of a variation device and the second output port thereof is connected to a second adjusting pressure chamber of the variation device, wherein the variation of the first hydraulic pump in terms of the swiveling direction and the pressure medium volume delivered at its first port and the pressure medium volume delivered at its second port is effected by means of the variation device.