Today, the diagnosis of gearbox defects is considered as one of the vital components of the industry, to improve the performance of various industries. The torsional vibration signal of the gearbox has qualitative and quantitative differences compared to the transverse vibration due to the difference in its nature and transmission path, and it is considered a suitable option for gearbox troubleshooting. In this research, the transverse and torsional vibrations of a simple one-stage gearbox were extracted through dynamic modeling of six degrees of freedom. Using the potential energy method, the hardness of engagement of the gear teeth and the effect of the crack in its root were investigated and the effect of the defect on the vibrations of the system was observed. Fault detection methods that use vibration analysis were analyzed in three domains of time, frequency and time-frequency on the transverse and torsional vibration signals of the system. Also, with the help of these methods, the growth of the crack and its location were identified, and the transverse and torsional vibration performance of the gearbox at different speeds was eva‎luated to diagnose the crack defect. Due to the non-stationary conditions of gearboxes in reality, it is of great importance to detect the fault of gearboxes in variable speed conditions. Based on this, after modeling the variable speed conditions of the gearbox and extracting its vibration equations, the vibration signals of the system were analyzed using the method of Variational mode decomposition, and with the help of Hilbert transform, the spectrum of the modes was formed, and the crack defect was diagnosed according to the rotation frequency of the gears. Also, in this research, a laboratory system was designed and built to verify the simulation results.

علي لقماني

سعيد ضيائي راد

حميدرضا ميردامادي , رضا تيكني