Analysis of Lubrication Characteristics of Electric Spindle Bearings

During the operation of the electric spindle, the spindle bearings undergo high-speed rotation, and good lubrication conditions are crucial. Poor lubrication can cause bearing contact fatigue, frictional damage, spindle abnormal noise, excessive vibration, spindle seizure, and other failures. Angular contact ball bearings are commonly used in electric spindle bearings, and lubrication is often achieved through grease lubrication. This study focuses on the analysis of the kinematic relationship of the 7009AC angular contact ball bearing under load conditions. NLGI3 lithium-based grease is used as the lubricant, and computational fluid dynamics (CFD) is employed as the numerical analysis method. The volume of fluid (VOF) is used to kinematically describe the flow field, and the distribution of grease under different speed conditions is obtained through computer numerical simulation and visualization processing. The results indicate that under high-speed conditions, the proportion of grease distribution on the outer raceway is greater than that on the inner raceway. As the speed increases, the pressure of the grease oil film decreases, and the film thickness increases.