Characterization of Vibration Transmission Paths for Gearbox Condition Monitoring

For gearbox condition monitoring, the position of the accelerometers can be crucial for the detection of possible defects. However, little information can be found in the literature for engineers in setting up condition monitoring. This study is to investigate the characteristics of gear vibration and its transmission path for sensor placement and reliable fault diagnosis. Vibration sources produced by gear meshing are transferred to the accelerometer through a path of shafts, bearings, and gearbox housing. Each transfer path has its own transfer function which is almost impossible to predict accurately that changes the vibrations in both magnitude and phase, varying significantly with the operating conditions. This study begins with the estimation of the path by the Frequency Response Function (FRF) technique and then it develops a response based estimation method to revise the base path adaptive to operating conditions for more accurate fault estimation. Both theoretical analysis and test result show that a better diagnosis when the path information is included in vibration signal processing and feature selection.