What is the working principle of a hydraulic steering device?

Working Principle of the Hydraulic Steering Device In the neutral position (when the steering wheel is not rotated), the oil from the oil pump returns to the oil tank through the steering gear. During power steering, the oil from the oil pump enters the cycloidal pinwheel meshing metering motor (metering motor) through the servo valve, driving the rotor to follow the steering wheel. According to the magnitude, direction, and amount of the steering wheel's steering angle, hydraulic oil is pressed into the left or right chamber of the cylinder, pushing the guide wheel to achieve power steering. The oil on the other side of the cylinder returns to the oil tank through the slide 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 core, dial, and linkage shaft in the steering gear. The metering motor presses hydraulic oil into the cylinder and pushes the guide wheel to achieve manual power steering. The volume difference between the two chambers of the cylinder can be replenished from the oil tank through the return port. Since the steering gear is used for low-speed heavy-duty 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.