Method and device for monitoring a gear system

Abstract

The invention concerns a method for monitoring a gear system () comprising at least two wheels, each wheel having a characteristic frequency (f, f), a vibratory or acoustic signal representative of these vibrations having been acquired by a sensor (), a vibratory or acoustic digital signal x(t) having been obtained, the method comprising, for each characteristic frequency of the system (), the steps of filtering (E) the digital signal by means of a filter in such a way as to obtain an image monitoring signal of at least one vibratory component of at least one defect; determining (E) the square envelope of said monitoring signal, defined by the square absolute value of the Hilbert transform of the monitoring signal so as to extract an image of the modulating signals associated with the rotation of the wheels from the monitoring signal; determining (E) the synchronous average of said square envelope relative to the period of rotation of a wheel of interest chosen from the wheels of the gear, said average helping attenuate spurious components in the envelope originating from other mechanical sources; determining (E) a monitoring indicator dependent on said synchronous average, said monitoring indicator being defined by the square root of the synchronous average normalised by the median value of the synchronous average.