Fault Feature Extraction of Elliptically Shaped Bearing Raceway
The elliptically shaped bearing (ESB) with a rigid, elliptical inner race and a flexible, thin-walled outer race is the most easily damaged core component of harmonic drive. The ESB rotates under cycle load of alternating stress due to its special elliptic structure. Hence, the impact noise produced by alternating between long axis and short axis is apt to conceal the fault features of ESB such as fatigue spalling and pitting. In order to diagnose the fault on raceway surface of ESB, a new method of CMWT-FH based on Continuous Morlet Wavelet Transform (CMWT) and FFT-based Hilbert (FH) spectrum analysis is proposed to extract the fault feature.