Development of a New Life Equation for Ball and Roller Bearings 2000-01-2601
The conventional rolling bearing life equation (1), which is based on the theory of Lundberg and Palmgren, has a problem in that it does not match the actual bearing life in all operating conditions. For instance, while the actual life of a bearing under clean lubrication is 20 times longer than the calculated life, actual life under contaminated lubrication is as low as one-tenth of the calculated life.
To solve this problem, the following life equation (Eq. 1: Advanced Bearing Life Equation) was developed with the aNSK life modification factor:
The new aNSK factor is based on data from bearing life aNSK tests involving over 450 roller bearings and over 550 ball bearings under a variety of operating conditions. The new life equation with the aNSK factor showed a satisfactory fit between calculated life and actual life.