When not turning, the control valve remains open, and the working chambers on both sides of the power cylinder piston communicate with the low-pressure oil return pipe and do not work. The oil output from the impeller pump flows back to the oil storage tank through the control valve. Because the throttling resistance of the steering pressure and the flow limiting valve is very small, the pressure of the output oil of the impeller pump is also very low, and the impeller pump is actually in an idling state.
When turning, the driver turns the steering wheel to drive the steering shaft and gear, so that when the distribution valve is in the working position corresponding to a certain turning direction, the corresponding working chamber in the steering power cylinder is disconnected from the oil return pipeline, and is connected to the output pipe of the impeller pump. The road is connected, and the other cavity is still connected to the oil return pipeline. The ground steering resistance is transmitted to the piston rod with the rack through the tie rod, forming a pipeline resistance much higher than the throttling resistance of the steering control valve. As a result, the output pressure of the impeller pump increases sharply. The high-pressure liquid enters the side of the power cylinder piston through the control valve, pushes the piston, and then pushes the rack to act as an afterburner.
The greater the steering angle, the greater the steering force, the longer the piston travel, the higher the pressure, and the greater the steering afterburner. When the steering wheel stops rotating, the control valve immediately returns to the middle position, so that the power cylinder stops working, that is, it has a follow-up function.