Thermal-flow coupling characteristics of hydraulic pump's piston/cylinder interface oil film

YU Qi-kuan1, WANG Dong-yun1, LI Sheng-hu2, JING Bao-de1
(1.College of Engineering, Zhejiang Normal University, Jinhua 321004, China;
2.Hangzhou Lilong Hydraulic Co., Ltd., Hangzhou 311228, China)

Abstract: Aiming at the problem that the plunger oil film is ultrathin and easy to break than accelerate the wear failure of the plunger pair, the oiltemperature heatflow coupling model was established after taking into account the viscositytemperaturepressure effect. After the analysis of characteristics of plunger oil film under different inlet temperaturein plunger chamber, the relationship between with the inlet oil temperature and the overall oil temperature and oil film thickness was established. The finite volume method was used to discretize the Reynolds equation and the energy equation, and the discrete equation was solved by the cyclic tridiagonal matrix algorithm. Subsequently the temperature and eccentricity in the three regions of the plunger suboil film were measured on a 360° oil film property test bench.The results indicate that the temperature change of the plunger suboil film changes gently at the inlet end and the outlet end, but there is a slight peak, which rises linearly in the middle. The minimum oil film thickness of the plunger pair follows the temperature when it rises and becomes thinner, and in the oil discharge area, the change is more obvious. When the oil temperature exceeds 45 ℃, the oil film thermal balance is destroyed, and the minimum oil film thickness is drastically reduced.
Key words: oil film characteristics; heat-flow coupling; piston/cylinder interface; axial piston pump;cyclic tridiagonal matrix algorithm（CTDMA）