Rolling bearing diagnostics by combination envelope analysis and Zoom-FFT

Envelope analysis has become an important approach for detection and diagnosis of rolling bearing incipient failure. But one of the on-going difficulties with envelope technique is to determine the best frequency band to envelop. This paper utilizes Hilbert zooming demodulation technique to diagnose rolling bearing early faults. Its significant novelty has two: on one hand, it gives a theoretical proof of the feasibility based on the analysis of,fault types and vibration signals of rolling bears; on the other hand, it integrates zooming and envelope analysis in frequency domain to get the demodulation spectrum of fault signal. Experiments. show that Hilbert zooming demodulation technique holds both high accuracy and fast speed in early fault diagnosis.