A Mixed Lubrication Model for Predicting the Lubrication Performance Degradation Behavior of Slipper Pair in Early Wear Failure

To reveal the lubrication performance degradation mechanism of the slipper pair in the high-pressure piston pump during early wear failure. The three-dimensional fractal function has been used to construct the surface morphology of the slipper, and combined with the oil film thickness equation to establish a mixed lubrication model of the slipper pair considering the microscopic change of the surface during the wear process. Based on the fractal theory, a method using fractal parameters (fractal dimension
$D$
and scale coefficient
$G$
) to describe the surface morphology change during the wear process is proposed. The variation of surface morphology, oil film thickness and pressure distribution of the slipper during wear degradation process are discussed, and the effect of wear depth on the degradation laws of leakage and oil film supporting force are analyzed. Finally, the wear degradation state simulation test of the slipper pair is carried out. The information on surface morphology, oil film thickness and leakage during wear process is recorded for the verification of the theoretical model. The proposed model can lay a theoretical foundation for accurately evaluating the performance degradation of the slipper pair and improving the fault prediction and predictive maintenance level of high-pressure piston pumps.