Bearing life

Under a certain load, the number of revolutions or hours the bearing experiences before pitting corrosion is called the bearing life.
The life of a rolling bearing is defined by the number of revolutions (or the number of hours of work at a certain speed): the bearing within this life should have preliminary fatigue damage (flaking or defect) on any of its bearing rings or rolling elements. However, no matter in the laboratory test or in actual use, it can be clearly seen that the bearing has the same appearance under the same working conditions, but 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 that a certain bearing can reach before damage is caused by wear and tear, and damage is usually not caused by fatigue, but Caused by wear, corrosion, seal damage, etc.
In order to determine the standard of bearing life, the bearing life and reliability are linked.
Due to the difference in manufacturing accuracy and material uniformity, even the same batch of bearings of the same material and size, used under the same working conditions, will have different life spans. 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 the longest to the shortest life is 20-40 times. 90% of the bearings do not produce pitting corrosion, and the number of revolutions or hours experienced is called the rated life of the bearing.

Rated dynamic load

In order to compare the bearing capacity of the bearing against pitting corrosion, when the rated life of the bearing is specified to be one million revolutions (106), the maximum load that can be carried is the basic dynamic load rating, denoted by C.
That is to say, under the action of the rated dynamic load C, the reliability of this kind of bearing working for one million revolutions (106) without pitting failure is 90%. The larger the C, the higher the load-carrying capacity.
For basic dynamic load rating
1. Radial bearing refers to pure radial load
2. Thrust ball bearing refers to pure axial load
3. Centripetal thrust bearing refers to the radial component that produces pure radial displacement