Abstract: Periodic impulse in vibration signals is one of the key indicators to diagnose localized damage of bearing elements. A new method, so called time-wavelet energy spectrum, is proposed for rolling element bearing fault diagnosis. The feature of periodic impulses in both time domain and frequency domain can be extracted effectively by this method. This method is applied to analyzing the vibration signals of bearings under normal and faulty (with damage on outer race, inner race and ball respectively) statuses, and its performance is compared with the traditional envelope demodulation method. It is found that the time-wavelet energy spectrum is more effective in extracting the periodic impulses features produced by localized bearing damage than the envelope demodulation analysis. It can not only extract the relatively significant fault feature of outer race damage, but also extract the weaker fault features of inner race damage and ball damage.

Key words: Fault diagnosis, Rolling element bearing, Time-wavelet energy spectrum, Wavelet transform