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 method (300) and control arrangement (210) for controlling a vehicle (100) to freewheel with engine off. The vehicle (100) has an engine (260) for propelling the vehicle (100) and a hydraulic power steering system (400). The hydraulic power steering system (400) comprises a primary power steering pump (270a) arranged to be driven by the engine (260) and a secondary power steering pump (270b). The method (300) includes: determining (301) when to start freewheeling the vehicle (100) with its engine off; and prior to starting the freewheeling of the vehicle (100) with engine off, determining (302) to start the secondary power steering pump (270b).

A vortex reservoir for separation of an aerated portion of a hydraulic fluid includes an upper chamber and a lower chamber, in fluid communication with the upper chamber, having a lower chamber sidewall. The lower chamber includes a lower lower chamber and an upper lower chamber. The lower chamber includes a lower chamber partitioning plate. The lower chamber partitioning plate is located between the lower lower chamber and the upper lower chamber. The lower lower chamber is in fluid communication with the upper lower chamber via a gap between the lower chamber partitioning plate and the lower chamber sidewall.

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 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.

Hydraulic bi-directional flow switches are disclosed. A disclosed example apparatus includes a piston disposed in a fluid channel between a first fluid connection and a second fluid connection, where the first and second fluid connections define a fluid pathway for hydraulic steering fluid. The example apparatus also includes a detector to detect a movement of the piston away from a default position of the piston, where the piston is to displace from the default position when the hydraulic steering fluid flows along the fluid pathway.

A self-centering double ended hydraulic steering cylinder that uses no electronics and a method of making the same. The self-centering double ended hydraulic steering cylinder has an elongated housing having end caps at opposing ends of the housing, wherein first and second rod portions are slidably disposed through the end caps. A piston is slidably disposed within the housing, the first and second rod portions extending from the piston, the piston defining first and second hydraulic fluid chambers within the housing. On each opposing end cap is a coiled spring for urging the piston toward a neutral position with the housing. A miniscule passage is formed into the piston so that hydraulic fluid flow through the piston that allows the springs to push the piston back to the neutral position.

A system and method for detecting the functional state of a piloted or direct-operated isolation valve in a hydraulic circuit is presented. In some examples the hydraulic circuit is a steering circuit and the isolation valve provides selective isolation between a hydraulic actuator and one or more metering valves. In some examples, the isolation valve assembly is movable between a first position, in which fluid flow between the metering valve and the actuator is enabled, and a second position, in which fluid flow between the metering valve and the actuator is blocked. When the isolation valve assembly is moved to one of the first and second positions, an inlet port and a pressure sensing port of the isolation valve assembly are placed in fluid communication with each other. When the isolation valve assembly is moved to the other of the first or second position, a second inlet port and the pressure sensing port are placed in fluid communication.