Abstract: The influence of phase reference estimation is addressed on the gearbox diagnosis . A method of phase estimation is developed based on Wigner distribution without tachometer. The objective is to supplement the current techniques of gearbox diagnosis based on time synchronous average. The proposed method focuses on the fact that gear local faults produce periodic local components in vibration signals. Based on a simplified vibration signal model, an analytic processing is proposed to describe the principle of the method. The technique is validated using dataset from a gearbox testbed. The results show that Wigner distribution is an effective tool for the phase estimation of gearbox vibration signal.

Key words: Fault diagnosis, Gearbox, Phase estimation, Wigner distribution