An investigation into defect induced excitations in rolling element bearings under dynamic radial load

External load on a bearing which supports the shaft is, normally, composed of static and time-varying components and are essentially dynamic in nature. The external load on a bearing is transferred to the housing in which the bearing is fixed through the elements of bearing viz., inner race, rolling elements and outer race. In the present work an investigation has been made to estimate the excitations caused by localized defects on different elements, viz., inner race, rolling element and outer race, of a bearing subjected to dynamic load. In this study, the dynamic load has been considered to be composed of a static and a harmonic component resulted due to a rotating unbalance. All the kinematic and dynamic parameters of the bearing have been assessed for dynamic loading and the spectra of excitations due to defects on different bearing elements have been obtained. Numerical results have been obtained for NJ204 bearing with a known radial clearance. The results show the variation in the spectra obtained for different contributions of external static and harmonic loading. These results are expected to satisfy some of the differences in experimental and theoretical spectra obtained by earlier researchers.