Experimental Investigation of Lubrication Regimes in High-Speed Precision Rolling Bearings under Variable Load Conditions

Abstract

High-speed precision rolling bearings are essential components in aerospace systems, machine tools, electric vehicle drivetrains, gas turbines, high-speed spindles, robotics, and precision manufacturing equipment, where they support rotating shafts while minimizing friction and ensuring accurate motion transmission. The lubrication regime established between rolling elements and raceways significantly influences bearing friction, wear, temperature rise, vibration characteristics, fatigue life, and overall operational reliability. Under variable load conditions, the lubrication film continuously changes due to variations in contact pressure, rolling speed, lubricant viscosity, and thermal effects, causing transitions between boundary, mixed, and elastohydrodynamic lubrication (EHL) regimes. Improper lubrication may lead to excessive friction, surface fatigue, lubricant degradation, and premature bearing failure. This study presents an experimental investigation of lubrication regimes in high-speed precision rolling bearings operating under different rotational speeds and load conditions. The proposed research integrates bearing test rigs, friction torque measurements, temperature monitoring, vibration analysis, oil film thickness estimation, and wear characterization to evaluate lubrication performance under realistic operating environments. Experimental results demonstrate that optimized lubricant selection and operating conditions significantly improve lubrication film stability, reduce friction coefficient, minimize temperature rise, suppress vibration, and extend bearing service life. The proposed investigation provides valuable engineering guidelines for improving the efficiency, durability, and reliability of high-speed precision rolling bearing systems employed in advanced mechanical engineering applications