Life prediction for linear rolling element bearings: A new approach to reliable life assessment

A new approach to the life assessment for linear bearings using three-parameter Weibull distribution is discussed and theoretical basic dynamic load ratings are calculated for linear motion ball guides (LMBG) and ball bushes. Life test experiments are also carried out for these two types of linear bearings with varying design features for each type. The concept of a minimum life prior to which there is no failure, is introduced in the analysis of the life test data. The effects of introducing ball cages in LMBGs and rounding of the edges in the case of ball bushes on their lives, basic dynamic load ratings, and the lambdab(m) factors are examined. It is observed that compared with a two-parameter Weibull distribution, all analysis based on a three-parameter Weibull distribution clearly reveals the differences in the lives of linear bearings for changes in their designs.