Vibration Monitoring for Local Fault Detection in Synchronous Belts

The possibility of diagnosing the presence of a fault in a synchronous belt transmission during its work, without dismantling it, by monitoring the vibrations of the pulley support, was investigated in this work. After a few simulations with a multi-body numerical model, several experimental tests were carried out in an apparatus made up of a test bench, motion sensors, a system of signal acquisition and software for data processing. The behavior of mechanical transmissions with healthy and faulty synchronous belts was compared. The damage was simulated by removing a tooth from the belt. The results show that a localized defect on a synchronous belt modifies the frequency spectrum of the motion signals measured on the pulley support. From the experimental tests performed, the following results were obtained: the direction of vibrations measured on the pulley support must be chosen so as to be parallel to the direction of the taut side of the belt; the presence of a defect can be seen in the frequency spectrum by the change in the amplitude of the peaks at the first harmonics of the run frequency; the best condition to highlight the different behaviour in the power spectra occurs when the transmission is under load.