A hydraulic steering system (1) includes a steering command device (2) having a steering sensor (3), a steering motor (6), a wheel sensor (9), a pressure source (P), and control means (12) controlling a fluid supply from the pressure source (P) to the steering motor (6), wherein the control means (12) has an open loop control (19). Such a steering system should have a good relationship between steering input from the operator and steering behaviour of the vehicle to be steered. To this end the control means (12) include in addition to the open loop control (19) a closed loop control (20), wherein cross-over transition means (21) are provided which are connected to the open loop control (19) and to the closed loop control (20) and control a transition between the open loop control (19) and the closed loop control (20).

A hydraulic steering system (1) includes a steering command device (2) having a steering sensor (3), a steering motor (6), a wheel sensor (9), a pressure source (P), and control means (12) controlling a fluid supply from the pressure source (P) to the steering motor (6), wherein the control means (12) has an open loop control (19). Such a steering system should have a good relationship between steering input from the operator and steering behaviour of the vehicle to be steered. To this end the control means (12) include in addition to the open loop control (19) a closed loop control (20), wherein cross-over transition means (21) are provided which are connected to the open loop control (19) and to the closed loop control (20) and control a transition between the open loop control (19) and the closed loop control (20).

A hydraulic steering arrangement (1) is described comprising a supply port arrangement having a pressure port (P) and tank port (T), a working port arrangement having two working ports (L, R), a steering unit (2) arranged between the supply port arrangement and the working port arrangement and a steering valve (3) arranged between the supply port arrangement and the working port arrangement. Such a steering arrangement should have a safety means. To this end in a manual steering mode the steering valve (3) is connected to the working port arrangement through the steering unit (2).

The present embodiments relate to a steering assist device and method, and a steering system. The steering assist device comprises: first and second input-side steering control modules for controlling an input-side steering motor so that an input-side instrument connected to a steering wheel is assisted; and first and second output-side steering control modules for controlling an output-side steering motor so that an output-side instrument mechanically separated from the input-side instrument and connected to a wheel is assisted, wherein the first and second input-side steering control modules and the first and second output-side steering control modules arbitrate a role assignment and can control a corresponding steering motor from among the input-side steering motor and the output-side steering motor according to the role assignment arbitration result.

The invention relates to a hydraulic steering device that hydraulically connects a steering cylinder to a supply system, whereby the supply system is hydraulically operatively connectable to the steering cylinder via a steering valve to form a main flow connection and the supply system is hydraulically operatively connectable to the steering cylinder via a flow regulation valve arrangement to form a branch flow connection that circumvents the main flow connection, whereby the flow regulation valve arrangement is triggerable by an electric control unit and the flow regulation valve arrangement comprises valve groups that are triggerable individually, which are respectively connected in the forward flow and return flow of the branch flow connection and a release-shutoff valve is assigned to the flow regulation valve arrangement. It is provided that the release-shutoff valve is connected between the flow regulation valve arrangement and the steering cylinder.

The present invention relates to a hydraulic steering system for a vehicle, in particular an industrial truck, comprising: a steering cylinder having two chambers and a hydraulic connection at each of the two chambers for activating a steering movement of at least one wheel of the vehicle; at least one hydraulic pump; at least one hydraulic tank for receiving hydraulic oil; and a steering block which comprises: two first hydraulic connections for connecting to the two hydraulic connections of the steering cylinder; at least two second hydraulic connections for supplying hydraulic oil from the hydraulic pump to the steering block and feeding the hydraulic oil back into the hydraulic tank; and a controllable valve assembly which receives control signals from a steering angle detection device and is designed to convey hydraulic oil to the steering cylinder on the basis of said control signals; the controllable valve assembly being further designed to be shiftable into at least one neutral position in which it allows a flow of hydraulic oil between the two chambers of the steering cylinder. The hydraulic steering system further comprises a pump device which is designed to stimulate the flow of hydraulic oil between the two chambers of the steering cylinder when the valve assembly is in the neutral position.

A hydraulic steering system (1) is provided having a steering device (2) and a symmetrically acting steering motor (3), said steering device (2) comprising a supply port arrangement having a high pressure port (P) and a low pressure port (T), a working port arrangement having two working ports (L, R), a control valve (14), two working lines (18, 19) each connecting said control valve (14) with one of said working ports (L, R), and a measuring motor (23). Such a hydraulic steering system should show a comfortable steering behavior. To this end said measuring motor (23) is arranged in one of said working lines (18, 19).

A hydraulic steering system (1) is provided having a steering device (2) and a symmetrically acting steering motor (3), said steering device (2) comprising a supply port arrangement having a high pressure port (P) and a low pressure port (T), a working port arrangement having two working ports (L, R), a control valve (14), two working lines (18, 19) each connecting said control valve (14) with one of said working ports (L, R), and a measuring motor (23). Such a hydraulic steering system should show a comfortable steering behavior. To this end said measuring motor (23) is arranged in one of said working lines (18, 19).

A hydraulic steering device hydraulically connects a steering cylinder to a supply system, wherein the supply system can be operatively connected hydraulically to the steering cylinder via a steering valve in order to configure a main flow connection, and the supply system can be operatively connected hydraulically to the steering cylinder via a flow control valve arrangement in order to configure an auxiliary flow connection which bypasses the main flow direction.

A hydrostatic steering device for an agricultural utility vehicle including a steering orbitrol, which can be controlled via a steering handle and by which a dual-action steering cylinder can be extended in accordance with a steering operation occurring at the steering handle. Depending on the operation direction of the steering handle, a first orbitrol connection forms a supply fed from a hydraulic high-pressure source, and a second orbitrol connection forms a return which communicates with a hydraulic reservoir, to actuate opposing working chambers of the steering cylinder. A hydraulic leakage flow occurring between the first and second orbitrol connections can be compensated with regard to a hydraulic operation of the steering cylinder via a valve assembly communicating with the high-pressure source and the hydraulic reservoir.