Life Test of Ceramic Ball Bearings by Staircase Method

Abstract

For the ceramic ball bearings in the step of the practical use, for which it is required to build up the data base on the various conditions in the life test, the sample size and testing time are the important problems in the life tests. The staircase method is discussed for these problems. This paper presents the life tests by the staircase method which involves comparison with the basic dynamic load rating by Weibull method, using the two kinds of ceramic ball bearings which differ from each other in the determining mechanisms of life. As the results the basic dynamic load rating by the staircase method is in agreement with that by Weibull method, and the testing time in the staircase method is shorter than that in Weibull method. It appears that the basic dynamic load rating of alumina ball bearings is extremely lower than that of silicon nitride ball bearings.