An Accuracy-Improved Torque Calculation Method for Ball Bearings Under Fully Flooded Lubrication—Part 1: Viscous Rolling Resistance Formulas for Contact and Non-Contact Zones

Abstract

Abstract. Accurate prediction of ball bearing torque is essential for reducing the energy loss in rotating machinery. Viscous rolling resistance, which dominates the ball bearing torque under fully flooded lubrication, has been estimated using regression formulas derived from isothermal elastohydrodynamic lubrication (EHL) analysis. However, existing regression formulas calculate different values due to differences in the integration domain and assumptions about contact position. This study proposes regression formulas for viscous rolling resistance that account for both contact and non-contact zones. For the non-contact zone, the proposed formula introduces the distance from the Hertzian contact center to each raceway edge as a parameter. Thereby, the proposed formulas enable accurate calculation across various Hertzian contact ellipse positions, sizes, and raceway widths. In addition, these proposed formulas demonstrate agreement with EHL analysis results and enable accurate estimation of the viscous rolling resistance across diverse integration domains compared to existing formulas.