Application of synchronous averaging to vibration monitoring of rolling element bearings

In this paper, the high frequency resonance technique, used for many years in the early detection of failure in rolling element bearings by vibration analysis, is combined with the technique of synchronous averaging, which has long been applied to vibration analysis of gears for the early detection of failure. It is shown that by synchronising the averaging of the envelope signal with a trigger signal taken from the rotation of the shaft, a representation is obtained for a bearing under radial load of the influence of the load distribution and the effects of the transfer path to the vibration transducer. By synchronising with the rotation speed of the shaft relative to the cage, an estimate is obtained of the distribution of the damage on the inner race of the bearing, and of the variations between rolling elements. The techniques are demonstrated by experiments on a laboratory test rig with a rolling bearing under radial load and multiple simulated spalls on the inner race. (C) 2000 Academic Press.