Abstract: In the fault diagnosis of multi-input and multi-output gearboxes and gearbox group, the orders of meshing frequency interfere with one another in the order tracking method, so it is difficult to use the order spectrum for gearbox fault diagnosis. In order to solve the problems mentioned above, a new method of fault diagnosis is proposed. The mono modulated gear meshing signals are filtered from vibration signal one by one with the adaptive time-varying filter whose center frequency is extracted by the sparse signal decomposition method based on multi-scale chirplet, and the bandwidth is set by the multiple of corresponding rotate speed. The fault diagnosis is conducted on the order spectrum of the filtered signals. The method effectively suppresses the influences of other gear meshing vibration from unrelated transmission systems and other non-order noise signals onto order spectrum. It favorably solves the problem of order interference, and enhances order spectrum more clearly, which provides an effective method for the fault diagnosis of multi-input and multi-output gearbox and gearbox group. A simulation and an application all are proved the effectiveness of the method.

Key words: Fault diagnosis, Gearbox, Order tracking, Sparse decomposition, Time-varying filter