Under certain load, bearing in case of pitting experience before the revolution or hours, known as the bearing life.
The life of rolling bearing with revolution (or in the hours of work under a certain speed) definition: within the life of the bearing, should be in any of its bearing ring or rolling on initial fatigue damage (spalling or defect). Whatever the test in the laboratory or in actual use, can be clearly seen, under the same working conditions, the appearance of the same bearing the actual life. In addition there are several different definitions of bearing "life", one of which is known as the "service life", it represents a certain bearing before damage to the actual life is by the wear and tear, damage usually is not caused by fatigue, but due to abrasion, corrosion, damage to the seal, and so on.
To determine the standard of bearing life, bearing life and reliability.
Due to the manufacturing precision, material uniformity degree of difference, even the same material, same size with a batch of bearings, under the same working conditions, its lifespan is not the same. If using statistical life is 1 unit, the longest relative life is 4 units, the shortest 0.1 0.2 units, the ratio of the longest and the shortest life for 20-40 times. 90% of the bearings do not produce pitting, experienced revolutions or hours called bearing rated life.
Dynamic load rating
To compare the bearing of the bearing capacity of the pitting, regulations bearing rated life expectancy of one million (106), can withstand the maximum load as the basic dynamic load rating, expressed as a C.
Is bearing under dynamic load rating C, this work bearing one million r (106) and reliability of 90% pitting failure does not occur, the greater the C higher bearing capacity.
The basic dynamic load rating
1. The centripetal bearing means pure radial load
2. The thrust ball bearing is refers to the pure axial load
3. The angular contact bearing is refers to produce pure radial displacement of the radial component