Rolling-Bearing Service Life Based on Probable Cause for Removal – A Tutorial
In bearing manufacturers’ catalogs and most engineering design books, the phenomena that limits bearing longevity and reliability is termed, “rolling-element fatigue.” This phenomena has been studied for over 120 years beginning in the 1890s with the pioneering work of Richard Stribeck in Germany, as well as the early part of the 20th Century with John Goodman in Great Britain and Arvid Palmgren in Sweden. Palmgren, in the first half of the 20th Century, was probably the most significant person to contribute to rolling-element bearing technology. In 1924 Palmgren provided the foundation for rolling bearing life calculation. He articulates that bearing life is not deterministic but that their lives are distributive. He meant that no two bearings in a group of bearings run under the same conditions will fail at the same time. He proposed the concept of an L10 life or a time at which 90% of a population of bearings will survive and where 10% have failed. He was perhaps the first person to propose a probabilistic approach to calculating the life of a machine element.