A hydraulic circuit, in particular to a hydraulic steering circuit for steering at least one vehicle axle, the hydraulic circuit including a first fluid path having a first end and a second end and providing fluid communication or selective fluid communication between the first end and the second end of the first fluid path; and a second fluid path providing fluid communication or selective fluid communication between the first end of the first fluid path and the second end (2) of the first fluid path, in parallel to the first fluid path or to a section thereof. In some aspects, the first fluid path includes a first hydraulic displacement unit; and the second fluid path includes at least a first proportional bypass control valve for controlling a bypass fluid flow in the second fluid path. The hydraulic steering circuit may be part of a driveline for a vehicle.

A hydraulic circuit, in particular to a hydraulic steering circuit for steering at least one vehicle axle, the hydraulic circuit including a first fluid path having a first end and a second end and providing fluid communication or selective fluid communication between the first end and the second end of the first fluid path; and a second fluid path providing fluid communication or selective fluid communication between the first end of the first fluid path and the second end (2) of the first fluid path, in parallel to the first fluid path or to a section thereof. In some aspects, the first fluid path includes a first hydraulic displacement unit; and the second fluid path includes at least a first proportional bypass control valve for controlling a bypass fluid flow in the second fluid path. The hydraulic steering circuit may be part of a driveline for a vehicle.

An operating method for a hydraulic servo steering system of a motor vehicle includes a steering cylinder that applies the supporting force to a steering gearing is integrated into a hydraulic circuit by means of a steering valve. The steering valve opening specifies the supporting force, wherein the supporting force is set by the steering valve in accordance with a steering torque applied to a steering wheel, by means of a gearing having play. The steering system further includes an actuator that acts on the gearing in order to cause relative adjustment of the gearing. The opening method provides for a compensation step in which, provided that a steering direction reversal is detected, the gearing is relatively adjusted by means of the actuator in a direction opposite the prior engagement direction of the gearing for a predefined duration or a predefined adjustment distance.

An operating method for a hydraulic servo steering system of a motor vehicle includes a steering cylinder that applies the supporting force to a steering gearing is integrated into a hydraulic circuit by means of a steering valve. The steering valve opening specifies the supporting force, wherein the supporting force is set by the steering valve in accordance with a steering torque applied to a steering wheel, by means of a gearing having play. The steering system further includes an actuator that acts on the gearing in order to cause relative adjustment of the gearing. The opening method provides for a compensation step in which, provided that a steering direction reversal is detected, the gearing is relatively adjusted by means of the actuator in a direction opposite the prior engagement direction of the gearing for a predefined duration or a predefined adjustment distance.

A valve system includes a valve configured to adjust a flow rate of hydraulic fluid in order to steer a work machine, and a control section configured to determine a command signal sent to the valve. The command signal determines a command flow rate of the hydraulic fluid based on a target flow rate corresponding to an input operation command and a change amount in the target flow rate. The control section is configured to control the change amount according to a magnitude of a reversal operation command when receiving the reversal operation command in order to operate the work machine in a direction opposite to a direction in which steering is operating. A work machine includes the valve system, a front frame, a rear frame, an articulate mechanism rotatably connecting the front frame to the rear frame, and a hydraulic actuator.

The present disclosure provides a steering system of an engineering vehicle, and a backhoe loader. The steering system includes: a direction control device, including a steering wheel, a steering cylinder and steerable wheels, the steering cylinder being in transmission connection with the steering wheel and the steerable wheels; a displacement sensor configured to detect a piston displacement of the steering cylinder; a return motor in transmission connection with the steerable wheels to drive the steerable wheels to return to a normal position; and a controller in signal connection with the displacement sensor and the return motor, and configured to output a control signal according to the piston displacement detected by the displacement sensor to manipulate the return motor to drive the steerable wheels to return. The backhoe loader includes the steering system.

A steering system for a work vehicle having a steerable wheel. The steering system includes a steering input device configured to provide a first steering input and a second steering input to move the steerable wheel. A pilot system is operatively connected to the steering input device and includes a first pilot line operatively connected to the first steering input and a second pilot line operatively connected to the second steering input. A piloted system is operatively connected to the pilot system and includes a direction control valve operatively connected to each of the first and second pilot lines and to a steering cylinder. The steering cylinder is coupled to the steerable wheel. The direction control valve responds to each of the pressure signals of the first and second pilot lines to adjust the position of the steering cylinder which in turn moves the steerable wheel.

A control apparatus controls the hydraulic connection between self steering wheels on a trailing vehicle, for example a grain cart, and the hydraulic system of a utility vehicle, for example a tractor, towing the trailing vehicle. An auxiliary circuit on the trailing vehicle forms a continuous loop receiving in series one or more wheel actuators associated with the self steering wheels. A valve arrangement is operable in a locked state or unlocked state in which the continuous loop is isolated from the tractor to prevent or allow a flow of fluid in the continuous loop regardless of the state of the tractor hydraulics. In a manual state, the flow in the loop is dependent upon the tractor hydraulics. In an automatic mode, a controller automatically operates the valve arrangement between the locked and unlocked states dependent upon one or more sensed operating conditions of the trailing vehicle.

A control apparatus controls the hydraulic connection between self steering wheels on a trailing vehicle, for example a grain cart, and the hydraulic system of a utility vehicle, for example a tractor, towing the trailing vehicle. An auxiliary circuit on the trailing vehicle forms a continuous loop receiving in series one or more wheel actuators associated with the self steering wheels. A valve arrangement is operable in a locked state or unlocked state in which the continuous loop is isolated from the tractor to prevent or allow a flow of fluid in the continuous loop regardless of the state of the tractor hydraulics. In a manual state, the flow in the loop is dependent upon the tractor hydraulics. In an automatic mode, a controller automatically operates the valve arrangement between the locked and unlocked states dependent upon one or more sensed operating conditions of the trailing vehicle.

In a steering assistance device 1, a steering control unit 74 causes a first auxiliary unit 14 to generate torque with reducing by a predetermined amount and causes a second auxiliary unit 20 to generate torque equal to or less than the decreased predetermined amount, in a case where the first auxiliary unit 14 is able to generate a steering assistance force such that a steering angle of a vehicle can reach a target steering angle determined according to curvature so as to make the vehicle travel in the center of a lane.