Influence of the De-Noising Method by Spectral Subtraction on the Diagnosis of Rolling Bearings

摘要

The aim of this article is to show the interest of the spectral subtraction for the improvement of the sensitivity of the scalar indicators (crest factor, kurtosis) within the application of a conditional maintenance by vibratory analysis on ball bearings. If we consider the case of a bearing in good condition of use, the distribution of the amplitudes in the signal is a gaussian kind. When the bearing damages, the appearance of spellings comes to disturb this signal, modifying this distribution. This modification goes through the presence of periodical impulses produced each time a rolling element meets a discontinuity on its way. Nevertheless, the presence of background noise induced by random impulse excitations can have an influence on the values of these temporal indicators. The de-noising of these signals by spectral subtraction in different frequency bands allows to improve the sensitivity of these indicators and to increase the reliability of the diagnosis.