Determination of tapered roller bearing system life index considering bearings preload and shaft stiffness

Abstract

Rolling bearings are considered to be rigid supports of a pinned nature. In fact, rolling bearings develop displacements that depend on the external load and the stiffness of the shaft on which they are supported. In addition, tapered roller bearings use preloading, which has an additional effect on the displacements in the bearings. these displacements affect the internal deformations in the bearings and thus the actual load on the bearing. This paper presents a methodology for determining displacements in bearings and actual loads in bearings, taking into account shaft stiffness and preload clamping. Then the bearing life was determined. Based on the obtained bearing life, the bearing life index was determined for the adopted load variants. On the basis of the results obtained it can be concluded that the consideration of the durability of individual bearings is insufficient, because it usually happens that when the durability of one bearing increases, the durability of the other bearing decreases. According to the author, the best solution is to combine the durability of both bearings and to consider the durability of the whole bearing system, not the individual bearings.