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 control system for steering rear caster wheels of a work machine. The control system has a steering mode that proportionally controls the steering of rear caster wheels while compensating the circuit to keep steering performance independent from the load generated by the rear caster wheels, a no steering mode that maintains the position of the rear caster wheels in the absence of a steering command, and a freewheeling mode that permits the rear caster wheels to rotate freely 360°.

A hydraulic control system for steering rear caster wheels of a work machine. The control system has a steering mode that proportionally controls the steering of rear caster wheels while compensating the circuit to keep steering performance independent from the load generated by the rear caster wheels, a no steering mode that maintains the position of the rear caster wheels in the absence of a steering command, and a freewheeling mode that permits the rear caster wheels to rotate freely 360°.

A power steering system includes a steering column assembly, a steering gear assembly, and a pressure sensor, and a torque sensor. The steering column assembly has a steering shaft and the steering gear assembly is operatively connected to the steering shaft. The steering gear assembly has an input shaft that extends through a valve housing and extends into a rack housing. The pressure sensor is arranged to provide a pressure signal indicative of a fluid pressure of at least one of a first cavity and a second cavity disposed within the rack housing.

A power steering system includes a steering column assembly, a steering gear assembly, and a pressure sensor, and a torque sensor. The steering column assembly has a steering shaft and the steering gear assembly is operatively connected to the steering shaft. The steering gear assembly has an input shaft that extends through a valve housing and extends into a rack housing. The pressure sensor is arranged to provide a pressure signal indicative of a fluid pressure of at least one of a first cavity and a second cavity disposed within the rack housing.

The invention relates to a steering system for at least one trailing or leading axle of a vehicle, comprising: a steering angle sensor for measuring a steering angle of wheels of a leading axle of the vehicle; a driving speed sensor for measuring a driving speed of the vehicle; an electric motor (1.2) that drives a hydraulic pump (2); a working cylinder (11) for steering the wheels of the trailing axle, which is joined to the hydraulic pump (2); a control device (1.1) which determines a trailing angle of wheels on the trailing axle of the vehicle, using the data of the steering angle sensor and the driving speed sensor, and which controls the electric motor in a corresponding manner, wherein the working cylinder (11) has a centre position borehole (1.3) via which hydraulic fluid can be emitted from the working cylinder (11), and a piston seals the centre position borehole (11.3) in the straight position of the wheels of the trailing axle, wherein the working cylinder (11) is connected to return valves (10 and 10.1), via which hydraulic fluid can flow back into a tank (6), wherein the centre position borehole (11.3) of the working cylinder (11) is connected to a centre position valve (12), via which hydraulic fluid can flow back into a tank (6), and wherein the return valves (10 and 10.1) and the centre position valve (12) are in the form of a poppet valve.

The present disclosure relates to a hydraulic steering device of an agricultural work vehicle comprising a steering pump for supplying a working fluid; an automatic steering unit which uses the working fluid to change the traveling direction of the agricultural work vehicle when automatic steering is performed by a control unit; a manual steering unit which uses the working fluid to change the traveling direction of the agricultural work vehicle when manual steering is performed by operating a steering handle; and an automatic cut-off unit which is for selectively cutting off the supply of the working fluid for the automatic steering to a steering cylinder of the agricultural work vehicle according to whether the manual steering is performed.

The present disclosure relates to a hydraulic steering device of an agricultural work vehicle comprising a steering pump for supplying a working fluid; an automatic steering unit which uses the working fluid to change the traveling direction of the agricultural work vehicle when automatic steering is performed by a control unit; a manual steering unit which uses the working fluid to change the traveling direction of the agricultural work vehicle when manual steering is performed by operating a steering handle; and an automatic cut-off unit which is for selectively cutting off the supply of the working fluid for the automatic steering to a steering cylinder of the agricultural work vehicle according to whether the manual steering is performed.

The present application provides a full hydraulic synchronous steering system for a low-speed heavy-load vehicle, where the system includes: a steering control mechanism and a steering actuator; by determining a desired steering curve between a steering wheel angle and a rear wheel angle, when a steering error exceeds an allowable error, a controller controls the opening and closing of an oil replenishment solenoid valve (5) and an oil discharge solenoid valve (4) to adjust an flow rate of the oil flowing into a steering cylinder (7), so as to ensure that the steering error is within an allowable error range, thereby implementing synchronous steering. A method for manipulating the full hydraulic synchronous steering system is further provided. The full hydraulic synchronous steering system and the method can improve synchronous steering capability of the low-speed heavy-load vehicle and change a steering ratio, thereby improving safety and direction feeling of a driver.

The present application provides a full hydraulic synchronous steering system for a low-speed heavy-load vehicle, where the system includes: a steering control mechanism and a steering actuator; by determining a desired steering curve between a steering wheel angle and a rear wheel angle, when a steering error exceeds an allowable error, a controller controls the opening and closing of an oil replenishment solenoid valve (5) and an oil discharge solenoid valve (4) to adjust an flow rate of the oil flowing into a steering cylinder (7), so as to ensure that the steering error is within an allowable error range, thereby implementing synchronous steering. A method for manipulating the full hydraulic synchronous steering system is further provided. The full hydraulic synchronous steering system and the method can improve synchronous steering capability of the low-speed heavy-load vehicle and change a steering ratio, thereby improving safety and direction feeling of a driver.