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

The friction pair wear in a high-pressure vane pump caused by solid particles in oil is a significant factor that affects the pump's service life. The study investigates the effects of solid particles on the tribological characteristics of the valve plate friction pair of a high-pressure vane pump. The effects of varying solid particle diameters (5–20 μm) and concentrations (0.001–0.015%) on the friction coefficient, wear rate, and surface morphology of the valve plate friction pair in a high-pressure vane pump were investigated. In addition, to study the effect of diameter and concentration of solid particle on the vane pump's volumetric efficiency, the volumetric efficiency of the vane pump was tested. According to the results, when the solid particle concentration was 0.001%, the friction coefficient increased first and then decreased as the solid particle diameter increased, with no obvious running-in process. Furthermore, the wear rate increased first and then decreased as the solid particle diameter also increased. When the solid particle diameter was greater than 15 μm, the friction coefficient decreased as the concentration increased, and a distinct running-in process was unobserved. During this time, the relationship between the valve plate's wear rate and the solid particle concentration was approximately linear. The wear of the valve plate with solid particles included the impact of scraping wear as well as the abrasive wear and slight adhesive wear caused by solid particles. The vane pump's volumetric efficiency decreased as the solid particle diameter increased with a linear relationship. The volumetric efficiency of the pump also showed a downtrend when the solid particle concentration increased. This research provides a reference for valve plate design and improving the performance of high-pressure vane pumps.