The Hollow-Ended Roller—A Solution for Improving Fatigue Life in Asymmetrically Loaded Cylindrical Roller Bearings

Abstract

To reduce the influence of misalignment (asymmetrical loading) on cylindrical roller bearings it is necessary to supplement the crown modifications of bearing elements. A unique hollow-ended roller design was developed for this purpose employing a three-dimensional finite element elasticity study to determine the stress state in the flexible rim section. The results when combined with the classical Hertzian contact stress distribution result in an accurate description of the shear stress field throughout the roller rim sections. Results of fatigue tests run under asymmetrically distributed loads supported the analytical efforts demonstrating significant improvements in L10 lives for the hollow-ended roller as compared to a solid roller. Peak stresses occurred in the vicinity of the contact area for both types of rollers with the solid exhibiting stresses 5 percent or more higher than those found in the hollow-ended type. Of equal importance, the observed failure mode for hollow-ended rollers under heavy load fatigue test conditions is one of conventional subsurface initiated O.D. spalling, thereby proving the rim design to be structurally sound.