Abstract
The load distribution and life formula for LMBG (Linear Motion Ball Guides) system constructed by two guide blocks on one rail are derived and the theoretical analysis is carried out concerning the basic dynamic.load ratings which are considered with the fluctuations of load distributions, the effect of linear strokes, load eccentricities, conformity factors etc., then the fatigue life test series made up two crowning patterns of guide block raceways are carried out. The results are as follows : (1) The basic dynamic load ratings of LMBG system increase in accordance with the increase in the strokes and decrease in the conformity factors, and decrease in accordance with the increase in the load eccentricities. (2) Theoretically, the probability of flaking occurrence in the guide block raceways is greater than that of the rail, because of the differences between the number of stress cycles and the basic dynamic load rating for the block and rail. (3) In the experiment, the most flaking occurrences are from the rail raceways due to the materials difference from the block and rail. (4) The life test results fit well to the 3-parameter Weibull distribution which is introduced to the location parameter i.e. the minimum life and the Weibull slope m=10/9. (5) The estimated basic dynamic load ratings from two test series are 50% and 90% for the theoretical values, respectively.
