Gears and Bearings Combined Faults Detection Using Hilbert Transform and Wavelet Multiresolution Analysis

Rotating machinery represents a significant class of mechanical systems, in which gears and bearings are the important and frequently encountered components that find wide spread industrial applications. Currently, vibratory analysis becomes the most reliable tool for the conditional maintenance of rotating machines. The associated techniques evolved so much that one passed from a simple late detection to the diagnosis, even the prediction. Researches in this field are directed towards the possibility of anearly detection, several signal processing techniques, often adapted to a precise defect type, were established throughout these last years. From those, demodulation by wavelets multiresolution analysis combined with Hilbert transform (Envelope analysis), which allowing making filtering and the demodulation at the same time. The objective of this work is the application of this technique for the detection of the faults in the rotatory machines and more particularly the gears and bearings combined faults.