The considerable stress of the formula of NSK Bearing Rated Life expectancy include: stress caused by external forces, by the surface conditions, lubrication, and the stress caused by the rolling contact surface in the kinematics . Through an integrated consideration of these stress NSK Bearing life, in specific applications, can predict more accurate to NSK Bearings performance and manifest.
   
Because of involves very complicated calculation and the content of the theory in detail is beyond the scope of this catalog. As a result, "SKF rated life" of a given are simplified, "Catalog" calculation. The user can through these terms, make full use of the bearings should be able to achieve life, reasonably put the overall size of machinery, and recognizing the lubrication of bearings and pollution impact on life expectancy.

Generally speaking, the rolling contact surface of the metal fatigue of rolling bearing are the main reason of NSK Bearings damaged .Therefore, a specific application, based on the rolling fatigue is sufficient to elect a suitable rolling bearing and its size. International Standard ISO 281 is the quasi-rolling contact surface of the metal fatigue as a foundation. But more importantly, should be put to do a full set of bearings are systems, there may be one of the components, namely, Cage, lubricants and seals, the life expectancy of Bearing durability plays in the same role, in some cases also played a leading role. Theoretically, when all the components achieve the same life expectancy, Life expectancy is the ideal job.

In other words, in order to let the actual work life of NSK Bearings reach the calculation Life ,at least the working life of its components must also need to reach the calculation of bearing life. Key components, including Cage, seals and lubricants. In real application, metal fatigue stillis  the most important factor.