The fault analysis of gearbox based on time delay correlation demodulation technology

Vibration analysis is an important mean for gear condition monitoring and fault diagnosis. This paper starts with the analysis on the characteristics of correlation function. It was found through theoretical analysis that the autocorrelation function does not change the modulation characteristics of the modulated signal, but has a significant characteristic of noise reduction. Thereby, the delay correlation demodulation method is established for the diagnosis of gear vibration fault. Implementation steps of this method are as follows: the first step is the autocorrelation analysis of the measured vibration signals; the second is the delay of autocorrelation function; the final step is the Hilbert transform demodulation of time-delayed autocorrelation function.