An in-situ measurement approach for the oil film characteristics of the spherical valve plate pair in axial piston pumps

Abstract

The three main ultra-thin oil films at the friction interface of piston pumps operate in a harsh environment of high pressure and speed, which is prone to carrying failure or leakage increase. Real-time monitoring of oil film performance is an ideal way to evaluate the structural design and conduct health management for pumps. However, the measurement scheme to simultaneously capture the oil film thickness, pressure, and temperature is absent. This paper presents a multi-parameter in-situ measurement approach for oil film characteristics, with application to spherical valve plate pairs. The added transition structure between the valve plate and the backend cover achieves both in-situ measurement and maximum protection of the pump's original parts and functions. A sophisticated test rig has been built to capture the oil film's performance at different pressures and speeds. The experimental results show that the approach can effectively assess the friction state of the valve plate pair.