Tribological Behavior of Friction Pairs in a High-Pressure Vane Pump under Variable Working Conditions

The tribological behavior of the friction pairs in a high-pressure vane pump under variable working conditions was experimentally studied; in particular, the effects of the varying sliding velocity (1.45-3.61 m/s) and contact pressure (0.11-0.44 MPa) on the friction coefficient and wear rate of the friction pairs in pumps with and without vanes in the vane slot of rotor were investigated. In both cases, the friction coefficient increased with increasing sliding velocity and decreased when the increase of contact pressure in two cases when the contact pressure is 0.22 MPa. Further, the wear rate decreased with increasing contact pressure. With increasing velocity, the friction coefficient was more influenced by the vane compared with wear rate. The main tribological mechanism of wear surface of the valve plate is mechanical ploughing. At a sliding velocity of 2.89 m/s, both with and without vanes, increasing the contact pressure resulted in a reduced friction coefficient and enhanced wear rate. When the contact pressure increased, the vane did not significantly influence the friction coefficient and wear rate. During this time, the wear surface morphology of the valve plate exhibited mainly mechanical plowing and adhesion wear marks.