Impact velocity modelling and signal processing of spur gear vibration for the estimation of defect size

Gears are one of the most common elements in any rotating machinery. If gear defect can be assessed, gearbox maintenance schedule can be optimally planned. This paper presents an impact velocity model relating measurable vibration signal to the defect size on the gear tooth flank. The analytical model was verified experimentally. The experimental results support the effectiveness of the analytical model in estimating defect size. In addition, experimental vibration signals were decomposed using empirical mode decomposition (EMD) technique. These decomposed oscillatory functions are called intrinsic mode functions (IMFs). Kurtosis value of selected IMF was calculated for early detection of fault.