Simulation and experimental research on the axial piston pump with series three-windows in valve plate

Abstract

To drive hydraulic cylinder directly by hydraulic pump closed-loop represents a hot research area in the field of electro-hydraulic control technology today, and is the most direct means to improve the energy efficiency of electro-hydraulic control system. So far, this technology has been well applied to the pump-controlled symmetric hydraulic cylinder. But for the differential cylinder that widely used in hydraulic technology, satisfactory results have not been achieved yet due to the constraint of asymmetric flow. Therefore, based on the principle of asymmetric valve controlled asymmetric cylinder in valve controlled cylinder technology, an innovative idea of asymmetric pump controlled asymmetric cylinder to address this problem is put forward. One scheme is to transform the oil suction window of the existing axial piston pump into two series windows. When in use, one window is connected to the rod chamber of the hydraulic cylinder and another is communicated with a low-pressure oil tank. So the differential cylinders can be directly controlled by changing the displacement or rotation speed of the pumps. With the software SimulationX, a hydraulic pump simulation model is set up, which considers the movement characteristics of individual piston, compressibility of oil as well as flow distribution area that changes with rotation angle. The pump structure parameters, especially the sizes of unloading groove of the valve plate, are determined through digital simulation, and the flow pulse characteristics of the pump are analyzed, on the basis of which the whole components for three distribution-window axial piston pump arranged in series are designed, and furthermore the prototype pumps are made. Moreover, the basic characteristics such as pressure, flow and noise of the pumps under different rotation speeds are measured on the test bench. The experiments verify the correctness of the principle.