A Comparison Of Vibration Amplitudes Of A Rotor Bearing System Due To Various Types Of Defects In Rolling Element Bearings

A comparative study for the prediction of amplitudes of a rotor bearing system for both localized and distributed defects in rolling element bearings has been reported in this paper. The rotor bearing system has been modeled as a multiple degree of freedom system and the excitation to the system has been assumed to be caused due to the presence of defects in inner race of the bearing. The types of defect studied include local defect such as pits and spalls and distributed defect in the form of race waviness. Discrete spectra have been obtained for both the types of defects. Significant components have been predicted at the harmonics of inner race characteristic defect frequency for both the types of defect and sidebands about the characteristic defect frequency have been predicted at the multiples of shaft frequency. Amplitudes of all these spectral components have also been obtained. Numerical results for all these components have been calculated for NJ 204 bearing. A comparison of these results for the two types of defects concludes the paper.