A Trace Redundant Lubrication Piezoelectric Microjet for Bearing System

A piezoelectric microjet, which can achieve lubrication on demand, is designed to realize the trace redundant lubrication for bearings. The volume of the ejected oil droplet can reach 0.0147 μ L with the velocity of the droplet as 0.91 m/s. A coupling analysis method is proposed to analyze the influences of excitation and oil properties on the dynamic characteristics of droplets. Based on the theory of central oil film thickness, an oil volume prediction model for the trace redundant lubrication of deep groove ball bearings is given. Experiments are carried out, the proposed coupling analysis method is verified by comparing the analysis results with experimental data, and the relative errors are given. The designed microjet is proved to be effective for redundant lubrication by testing its actual lubricating performance. The numbers of voltage pulses, which are required to achieve trace redundant lubrication under different excitations and operating conditions, are given. The validity of the proposed oil volume prediction model is proved by comparing results obtained from experiments and theoretical calculations, and the relative errors are given.