Fault characteristic frequency analysis of elliptically shaped bearing

Elliptically shaped bearing (ESB) with complicated kinematics characteristic is easily damaged, there is not a theoretical formula for ESB fault characteristic frequency (FCF) due to its geometrical structure. A theoretical calculation method for ESB FCF based on analysis of the relationship between geometry and kinematics characteristics is proposed. The identification accuracy of fault type can be improved. The continuous Morlet wavelet transform (CMWT) combined with FFT-based Hilbert (FH) analysis (i.e., CMWT-FH) is utilized to extract the fault feature by suppressing the dominant rotational excitation of ESB against the FH method. Experiments are performed to verify the effectiveness of the proposed method. The experimental FCFs identified from the CMWT-FH spectrums of ESB signals are evidently close to the theoretical values calculated by using geometry and kinematics parameters of ESB (the errors are within 2%). The theoretical calculation method for ESB FCF has practical reference for the accurate detection in fault diagnosis. (C) 2020 Elsevier Ltd. All rights reserved.