Characteristics of transmission error and vibration of broken tooth contact

One of the most important research topics relating to the development of a vibration-based condition monitoring system for a gearbox is that of quantitative analysis and testing of the effect of gear tooth damage on gearbox vibration. This paper presents a finite element model of the Transmission error (TE) and its associated characteristics, together with experimental results of vibration of broken tooth contact in a spur gear. The two-dimensional finite element model is developed to analyze the TE of the spur gear, and the TE for both the normal contact and broken tooth contact state of the spur gear pair are analyzed. As a result, the developed FE model well represents the difference in the static TE for a single-tooth and double-tooth contact of the undamaged and damaged gear pair. The Peak-to-peak magnitude of the static TE of the full-tooth fractured gear pair is significantly higher than that of undamaged gear pair. While the Peak-to-peak TE (PPTE) of the damaged gear tooth increases with increasing load, the ratio of PPTE of the undamaged gear pair and the full-tooth fractured gear pair decreases exponentially with increasing load. This shows that, to determine the fault level of gearbox, it is necessary to carefully apply the condition indicator when analyzing the impulse character of a vibration signal.