The dynamic behaviour of a system that includes a rolling bearing

Abstract

To enable a reduction of cost and time-to-market, fast and accurate predictions are required of the dynamic characteristics of new products in the earliest stage of design. A growing number of these new products have rotating components, which are supported by rolling element bearings. Although ball and roller bearings have a significant and complex contribution to the dynamic behaviour of machinery, they are often subjected to rigorous assumptions in the case of modelling. At present many bearing models still fail to describe adequately the stiffness of the outer (and inner) rings and the actual stiffness and mass distribution of the connecting bearing housings, the time-dependent variations of the bearing stiffness (parametric excitation), the damping in the elastohydrodynamically lubricated contacts and the vibrations generated by form deviations. Therefore, a new method is presented, which accurately describes the time-dependent stiffness and mass properties of a rolling bearing application in an efficient way. The method enables a full transient analysis to study the effect of time dependent system properties, form deviations and mounting errors. Also the damping in ball and roller bearings is assessed, by comparing the results of advanced numerical simulations with experimental data. The new modelling method is used to investigate how damping and parametric excitation interact in a real bearing application. The increased level of accuracy that is obtained with the present method is elucidated by validation measurements.