Vibration diagnosis method of multistage gearing to point out ghost noise source due to amplitude fluctuation analysis

Ground gears sometimes bring peculiar vibration called 'ghost noise' whose frequency is non-integer order of mesh frequency. The cause of ghost noise is surface undulation due to manufacturing process. But the undulation is slight and detection with tooth surface measurement sometimes become difficult. To point out source gear of ghost noise, we propose 'amplitude fluctuation analysis' that assumes ghost noise has the cycle of least common multiple tooth number of meshing pair because just the same tooth pair mesh again. The proposed method can make clear which gear pair is the source of ghost noise. Combining this method and synchronous averaging method, we can point out the source gear completely. Experimental verification results with double reduction helical gear system shows that proposed method is effective.