Utilization of Synchronous Averaging of Vibration for Diagnosis of Gear System to Estimate Tooth Error

Generally, gear vibration behavior has base frequencies equal to meshing frequency and its harmonics. But it has become known that slight undulation even on ground gear surface sometimes generate peculiar vibration behavior that is non-integer order of meshing frequency, and it is called ‘ghost noise’. In the normal cases, the gear pair that is the source of vibration can be located by considering mesh frequencies of each gear pair and their harmonics. But if ghost noise components exist, it becomes difficult to detect which gear pair is the source. Therefore diagnosis method to detect ghost noise source with measuring vibration is required. In this study, we proposed the utilization of synchronous averaging to distinguish the source of ghost noise components. With this method, we could separate the effect of driving and driven gear from each other. The estimation results with synchronous averaging were verified with precise tooth surface measurements.