Spectral properties of signals from a gear-pair transmission with evolving damage

摘要

In this paper we analyze signals recorded by a number of accelerometers located on the gearbox casing of the Mechanical Diagnositc Test Bed (MDTB) at Penn State's Applied Research Laboratory. It is well known that the set of excited frequencies for a gear-pair is quite large, with the largest magnitudes located around the gear pair meshing frequency and its harmonics. However, we hsow these gear-pair spectra exhibit a simple structure not previously reported. In particular, we show the significance of the return frequency, defined as the meshing frequency divided by the least common multiple of the numbers of teeth on the pinion and gear: almost all of the observed RPM-dependent frequencies are located at numliples of this frequency, throughout the life of the gear-pair. We also show how spectral data for different RPMs cna be used, in principle, to estimate the frequency response characteristics for the signal transmission path connecting the excitation source (the gear pair) to an externally mounted sensor.