A Fast Calculation Approach for Elastohydrodynamic Finite Line Contacts Applicable to Online Calculations of Rolling Bearing Models

Abstract

Finite line contacts in rolling element bearings are usually under the regime of elastohydrodynamic lubrication (EHL). To obtain deeper insights into bearing performance, it is necessary to directly couple EHL contact models into bearing models. However, the existing EHL contact models are either too time consuming to be employed in the bearing model or too simplified to consider tilting contact behaviors and actual roller profiles. A fast calculation approach for EHL finite line contacts is proposed by combining the empirical film thickness formulas that have been developed for decades and an improved slicing technique that considers the coupling behaviors between slices. The proposed approach can not only predict the contact stiffness (normal contact stiffness and tilting contact stiffness) and contact states (contact pressure and film thickness) accurately but also is universal for different profiled contacts and material properties. The proposed approach costs only a few milliseconds for a single load case, which enables it to be directly employed in bearing models. Besides, the proposed approach is more of a framework, the use of which can be extended by involving different film thickness formulas and correction factors to consider complicated EHL behaviors such as thermal effects, shear thinning effects, surface roughness, lubricant starvation, and so on.