Application of Wavelet Packet and Hilbert Operator to the Fault Diagnosis of Rolling Bearing

The fault signal of rolling bearing has the feature of nonstationarity. To apply wavelet packet to decompose and reconstruct the vibrational signals collected from testing at first, then the Hilbert operator was applied to achieve the purpose of demodulating the envelope. Finally, the signals after refining envelope spectrum will expand the information of defects. And then extracting the characteristic frequency of fault signals and judging the fault location of the bearing. The experimental analysis shows that wavelet packet and Hilbert operator could be applied to extract the characteristic defect frequency of rolling bearing effectively, and in the other word this method is effective to detect the class of local damage of rolling bearing.