The present disclosure relates to a load-sense system such as a load-sense steering system that operates in a static load-sense mode for low flows and operates in a dynamic load-sense mode for high flows.

The present disclosure relates to a load-sense system such as a load-sense steering system that operates in a static load-sense mode for low flows and operates in a dynamic load-sense mode for high flows.

A hydraulic system for controlling a pair of steerable caster wheels includes a left side actuator and a right side actuator. A rear steering control valve is moveable between a first state for disabling direct control of the left and side actuators and a second state for enabling direct control the left and right side actuators to provide a steer response. A fluid connection continuously connects the pressure source and the fluidic tie rod fluid circuit in fluid communication when the rear steering control valve is disposed in one of the first state and the second state to continuously supply the pressurized fluid to the fluidic tie rod fluid circuit.

A secondary steering pump system may include a secondary steering pump, a bypass valve having a first bypass position configured for placing the secondary steering pump in fluid communication with a hydraulic tank and a second use/testing position configured for placing the secondary steering pump in fluid communication with a steering control circuit. The system may also include a solenoid valve configured for actuation by a solenoid and for selectively actuating the bypass valve from the first position to the second position. The system may also include a pressure sensor configured for sensing pressure in the system.

A secondary steering pump system may include a secondary steering pump, a bypass valve having a first bypass position configured for placing the secondary steering pump in fluid communication with a hydraulic tank and a second use/testing position configured for placing the secondary steering pump in fluid communication with a steering control circuit. The system may also include a solenoid valve configured for actuation by a solenoid and for selectively actuating the bypass valve from the first position to the second position. The system may also include a pressure sensor configured for sensing pressure in the system.

A turning system is configured to move a turning shaft to turn a left wheel and a right wheel of a vehicle. The turning shaft is configured to couple the left wheel and the right wheel to each other. A torsion bar is engaged with the turning shaft via a steering gear box. The turning system includes: a turning mechanism including (i) an electric turning mechanism including an electric motor configured to rotate a portion of the torsion bar which is located upstream of the steering gear box and (ii) a hydraulic turning mechanism configured to apply a moving force to the turning shaft in an axial direction, the moving force being produced by a hydraulic pressure; and an electric-motor controller configured to control the electric motor based on a frictional force in the turning mechanism and a road-surface reaction force that acts between (a) a tire on the left wheel and a tire on the right wheel and (b) a road surface.

A hydraulic steering arrangement includes a supply port arrangement having at least a supply port, a return port arrangement having at least a return port, a working port arrangement having two working ports, a first valve arrangement having a first supply side connected to the supply port arrangement and a first output side connected to the working port arrangement, a second valve arrangement having a second supply side connected to the supply port arrangement and a second output side connected to the working port arrangement, and a steering command device. In a neutral steering angle, the second valve arrangement connects the first output side to the return port arrangement and the first valve arrangement connects the second output side to the return port arrangement.

A hydraulic steering arrangement includes a supply port arrangement having at least a supply port, a return port arrangement having at least a return port, a working port arrangement having two working ports, a first valve arrangement having a first supply side connected to the supply port arrangement and a first output side connected to the working port arrangement, a second valve arrangement having a second supply side connected to the supply port arrangement and a second output side connected to the working port arrangement, and a steering command device. In a neutral steering angle, the second valve arrangement connects the first output side to the return port arrangement and the first valve arrangement connects the second output side to the return port arrangement.

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 gear apparatus (2) for a motor vehicle (1), comprising a hydraulic steering gear (11) and an electromechanical actuator (7) which is configured to actuate a working valve (10) of the hydraulic steering gear, it being possible for hydraulic fluid to be conducted out of a fluid reservoir (14) selectively into one of at least two working spaces (12) of the hydraulic steering gear (11) in a manner which is dependent on a position of the working valve (10), the steering gear apparatus (1) having a fallback device (16) which is configured, in particular in emergency operation of the steering gear apparatus (2), to selectively conduct hydraulic fluid into one of the at least two working spaces (12) independently of the position of the working valve (10).