Automobile gear, bearing and differential will produce vibration when working. Once there is a fault, the amplitude distribution of its vibration signal will change, so the vibration signal is the carrier of the fault characteristics of automobile main reducer. If the speed of driving wheel of automobile gear pair is N1; If the speed of the driven wheel is N2, the rotation frequency of the automobile gear is:
The change frequency of meshing stiffness of automobile gear (i.e. meshing frequency) is:
The speed fluctuation of automobile gear, uneven tooth pitch and eccentricity of automobile gear shaft will lead to frequency modulation and a family of sidebands around the meshing frequency. The interval of sidebands is the rotation frequency of automobile gear shaft.