Signal processing techniques for gears quality control and for detecting specific defects

The vibration of an electrical motor with a three stage epicyclical gear has been used for the assessment of its quality and for determining the presence of three kinds of defects in the system. The vibration has been measured via a tri-axial accelerometer allowing to monitor the vibration in the three directions (radial, tangential and axial) and to combine their information for the damage detection issue. A statistical processing analysis has been performed on a sample of 100 good motors and 30 damaged ones in order to individuate the latter ones. This procedure can also be applied for quality control of the motors in production lines where the damaged motors can be discarded and deepen controlled. The discarded motors, i.e. the damaged ones, have undergone a further deterministic analysis for the identification of the defect typology. This procedure is deterministic because it allows to recognize the defects by analyzing the frequencies of maximum vibration level linked to the cinematic of the epicyclical gear. By combining the two levels of processing, damaged motors can be discarded in on-line quality control and the defect individuated afterwards.