Under a certain load, the number of rotations or hours that the bearing undergoes before pitting is called bearing life.
The life of a rolling bearing is defined as the number of revolutions (or hours of work at a given speed): bearings within this life shall suffer initial fatigue damage (spalling or defect) on any bearing ring or roller. However, no matter in the laboratory test or in the actual use, it can be clearly seen that under the same working conditions, the appearance of the same bearing, the actual life is very different. In addition, there are several different definitions of bearing "life", one of which is the so-called "working life", which means that the actual life of a bearing before damage can be achieved by wear, damage is usually not caused by fatigue, but by wear, corrosion, seal damage and other reasons.
In order to determine the standard of bearing life, the life and reliability of bearings are linked.
Because of the difference of manufacturing precision and material uniformity, even if the same material, the same size of the same batch of bearings, under the same working conditions, its life is not the same. If the statistical life is 1 unit, the longest relative life is 4 units, the shortest is 0.1-0.2 units, and the ratio of longest to shortest life is 20-40 times. 90% of bearings do not cause pitting, and the number of revolutions or hours experienced is known as the rated life of bearings.