Acoustic diagnosis improves maintenance of grease lubricated bearings

This paper describes effectiveness of applying acoustic diagnosis to the greasing work. When we hear abnormal sounds from grease lubricated bearings, we try greasing. As a result, usually abnormal sounds fade away. But after a while sometimes the sounds appear again. Therefore we try greasing again. The sounds fade away at the time but later appear again. We try greasing again and again but the results are the same. By this time, the temperature of the bearing has increased a lot. If the temperature increases over the criteria, the life of the bearing and grease become short. We can avoid the repetitious greasing work with acoustic diagnosis. We can decide regreasing or not by the result of the diagnosis. Moreover we can find signs of wear of bearings by the result. (author)