Analysis of Friction Characteristics of Valve Plate Pair in an Axial Piston Pump Considering Cylinder Block Dynamics

Abstract The lubrication properties and friction characteristics of the valve plate pair play a vital role in determining the overall lifespan of the axial piston pump, which makes the analysis of these parameters of significant importance. In this paper, the lubrication model of the cylinder block/valve plate sliding interface of the axial piston pump, considering elastic deformation and cylinder block dynamics, is established. The oil film carrying pressure and asperity microcontact pressure are calculated using the Reynolds equation, Greenwood–Williamson asperity microcontact model, and Hertz contact theory. The dynamic analysis is carried out, and the Newton–Raphson iterative method is introduced to solve the nonlinear equations. The influence of working pressure, cylinder speed, and sealing belt width on the friction characteristics of the valve plate pair is analyzed using the numerical calculation model. The simulation results demonstrate the dynamic changes of the cylinder block and the impact of them on lubrication properties and friction characteristics. The experimental results of the friction coefficient at different cylinder speeds are consistent with the simulation results in trend and accurately reflect the fluctuation of the friction coefficient.