Pressure transformation ratio characteristics of kidney‐shaped holes variable four‐port hydraulic transformer

Abstract

The kidney-shaped holes variable four-port hydraulic transformer of inlet and outlet equal flow is proposed, such as the theory, the flow of port A and port B is the same and equivalent to a hydraulic motor. The flow of ports O and T is the same, and the equivalent of a hydraulic pump. The A and B kidney-shaped holes of the valve plate are the same. The O and T kidney-shaped holes are the same. The transformer ratio can be changed by adjusting the control angle of the valve plate. The mathematic models of displacement, angular torque, and pressure transformation ratio about the four-port hydraulic transformer are built. The derivative relationship between the pressure transformation ratio and flow of port B, recycling pressure difference, and viscosity is deduced, respectively. Based on it, the influence characteristics of the three factors on the pressure transformation ratio are obtained. The result of theoretical analysis and simulation shows that the increment in the flow of load circuits leads to a decrease in the pressure transformation ratio, while the decrease in viscosity and the increment in recycling pressure difference lead to an increase in the pressure transformation ratio.