Ferrographic analysis of pivot jewel bearing in oil-bath lubrication

The wear mechanism and life of the pivot jewel bearing in oil bath lubrication needs to be well understood. Forty five spinning wear test sets were built to reveal the wear behavior and wear life to achieve proper design of pivot bearing for high speed application such as in flywheels for energy storage, small centrifuges and fabric spindles. The ferrographic analysis of the used oil in wear test showed that the wear debris particles had the length of 0.5-30 of micrometers, had glossy surface and distributed on the ferrogram in strings. Some special wear particles such as ball, curling chip, and sliver were also found on the ferrogram. Four main kinds of substances in the wear particles were iron, iron oxides, non-ferrous metal and friction polymer. Image segmentation by recognition of background color presented the covered area of the wear particles on the freogram, and the volume of the wear particles was calculated according to the characteristics of the particles. The wear particle quantity analysis showed that the jewel-pivot bearing in oil lubrication could be used for long time duration in the vertical support system of small, high speed rotating machinery.