Prediction on the lubrication and leakage performance of the piston–cylinder interface for axial piston pumps

Abstract

Hydraulic piston pump has the advantages of high efficiency and low-pressure pulsation and has been widely used in the field of construction and agriculture machinery. However, the oil leakage problem, especially the internal leakage of the piston, seriously affects the efficiency of the pump and causes unstable state and high noise. First of all, to improve the performance of the hydraulic pump, a nonlinear mathematical model of the Reynolds equation and energy equation was established to predict the oil film thickness and pressure distribution. What's more, the influence of multiple parameters such as pressure, temperature, swash plate angle, leakage clearance, and the length of leakage flow path on the internal leakage of the piston–cylinder interface was explored. Last but not the least, a test rig was built to measure the corresponding values and to evaluate the effectiveness of the mathematic model. Simulations and experiments consider the variables such as pressure, temperature, and swash plate angle. Both results show that the nonlinear mathematical model could predict the piston pair leakage accurately, so it could be an effective way to improve the design of the piston–cylinder surface structure, gaining higher efficiency.