Gear Fault Diagnosis Based On Wavelet Analysis

With the development of science, technology and production, the technology of fault diagnosis for mechanical equipment is being valued and perfected increasingly. Gear is the key part in gear drive which is one of the most general modes in mechanical equipment and therefore fault diagnosis for gear can achieve great economy and society effect.Due to the unsteadiness of the vibration signal, conventional methods of gear fault diagnosis based on steady signal processing, which consist of time domain and frequency domain analysis method, are not as effective to local defect as to dispersed defect of gear. Possessing the property of time-frequency localization and the ability of unsteady signal processing, wavelet analysis has become the most conspicuous one in the new diagnosis methods in recent years.This paper has made the following researches on the application of wavelet analysis to local fault diagnosis for gear;1. The development of technology of fault diagnosis for gear, fault forms, mechanism and characteristics of gear vibration, and common methods of fault diagnosis for gear are mentioned systematically.2 The fundamental theory of wavelet analysis is introduced.3. A power spectrum analysis method based on the phase of complex- wavelet-transform, which derives fault information from gear vibration signal by phase, is presented.4. A method using transient frequency based on complex-analytical- wavelet-transform, which combines Hilbert transform with wavelet transform and possesses adaptive analytical ability, is proposed.5. A study is made on the energy spectrum estimation approach based on Gaussian- chirplet-transform, which is superior to conventional power spectrum estimation in local fault diagnosis for gear.Experimental results show these proposed methods, which can protrude the sideband structure of gear, are practical in gear fault diagnosis and of application and more thorough research value.