Abstract
Tribology recognizes its significance largely through maintenance activities and, at the same time, maintenance embraces a great number of tribological machine items. Maintenance tribology has therefore played an important role in successful machinery operations. In particular, since most failures of machines having rotating parts are caused by damage to bearings, there exist increasing demands for detecting damaged bearings at an early stage. From this point of view, the author introduces some diagnostic evaluation methods of machinery abnormalities based on maintenance tribology. The topics introduced here include such research activities as oil monitoring and analysis, diagnostic monitoring by vibration, acoustic emission and ultrasonic technique.
