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

Abstract

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.

Effect of solid particles in oil on tribological characteristics of the valve plate friction pair of a high-pressure vane pump

“…The working principle of the tester is explained as follows, as shown in Figure 3. 15 The rotor of vane pump test model was driven by the shaft. The rotor rotates at a certain speed.…”

“…The data of test force, shaft speed, and friction torque were collected by three kinds of sensors and transmitted to the computer for real-time processing. 15 To study the tribological characteristics of the friction pair composed of the rotor and valve plate, the vanes are not installed on the rotor during the test. The wear and friction coefficient of the valve plate can be obtained through the test…”

“…where w s is the wear rate of valve plate ( × 10 −8 mm 3 / Nm); f is the friction coefficient of the friction pair; Δm is the wear mass of valve plate (mg); ρ is the density of bronze coating on the valve plate (mg/mm 3 ); T is the friction torque of friction pair (N•m); R is the friction radius of friction pair (m); and N is the loading force of friction pair (N) 15 ; l is the sliding distance of the friction pair(m), it can be calculated using equation (3).…”

“…The friction and wear of the valve plate were tested by a friction and wear test system, and the system was shown in Figure 2. 15 And it mainly consisted of a friction and wear tester, a test model of vane pump, a data acquisition computer, and a hydraulic station. The small hydraulic station can supply the oil pressure and take away the heat of the oil for the vane pump test model.…”

“…The data of test force, shaft speed, and friction torque were collected by three kinds of sensors and transmitted to the computer for real-time processing. 15…”