What is the working principle of a hydraulic steering device?

Hydraulic Steering Device Working Principle In the neutral position (when the steering wheel is not rotated), oil from the pump returns to the oil tank through the steering gear. During power steering, oil from the pump enters the cycloid pinion meshing metering motor (metering motor) through the servo valve, driving the rotor to follow the steering wheel. According to the angle, direction, and amount of steering wheel rotation, hydraulic oil is pressed into either the left or right chamber of the cylinder, pushing the guide wheel to achieve power steering. Oil from the other side of the cylinder returns to the oil tank through the spool valve. During manual power steering, when the engine is off, the steering wheel is operated by manual force. The rotor of the metering motor is driven by the valve spool, dial, and linkage shaft in the steering gear. The metering motor presses hydraulic oil into the cylinder and pushes the guide wheel, achieving manual power steering. The volume difference between the two chambers of the cylinder can be supplemented by the oil tank through the return port. Since the steering gear is used in low-speed heavy vehicles, to prevent the steering wheel from kicking back, the structure is designed as a non-responsive structure. External forces acting on the guide wheel cannot be transmitted to the steering wheel, and the driver has no road feel.