1), bearing from start to use the first SKF Bearing Static Load Rating http://www.skf-nsk.org/ material fatigue phenomenon appeared during the period of the length and the bearing rotating speed, the size of the load, lubrication clean degree have relations.



2) under the surface shear stress and fatigue load is formed by periodic appears as a result, after a period of time, the shear stress is causing tiny crack skull, then gradually extends to the surface, when the rolling piece after the split cranium, then some crack block off, form the so-called "peeling phenomenon", and then continue to expand as peeling, bearing damage in use.



3), the above is the description of the bearing fatigue, it was originally occurred under the surface, while the original skin conditions are usually very mild, but increased with the increase of stress and crack block, lead to the spread of the peeling area, the damage situation usually lasts a long time, its phase is visible at the time of noise and vibration increase.



4), bicycle bearing damaged in the primary stage, is likely to be just turns hard to feel, and later found that the rotation are pitting, and once appeared pitting feeling, bearing is not can't use, just proceed in each beads and shaft gear and shaft bowl occurs more wear and more serious damage, because the bike is a way of low speed high extreme pressure type bearing, peeling phenomenon is serious, so even if the surface is not so used, but intangible silent your motivation of energy consumption, and the feeling of you is likely to be just think don't know why not ride a bad car.



5), so before bearing totally destroyed it, it provides users to find enough time, do not ignore the existence of this kind of friction, it will cause a decrease in the speed of riding, make long distance energy consumption greater speed slower.

If subtle for surface roughness, if there is proper thickness of lube film, the surface stress generated by the probability is quite low, which is why the choice of appropriate for the reason of engine oil for lubrication, however, if the load exceeds the oil film pressure value of pu (the fatigue load limit, such as high speed, high pressure shock), material fatigue will come sooner or later.

For modern high quality imported bearing, its nominal rating or basic life may be linked to a particular application of actual service life have very big difference. In a particular application, the service life is affected by various factors, including lubrication, pollution level, not in degree and installed correctly or not and environmental factors, etc.



So the ISO 281:1990 / Amd then contains a modified life equation to supplement the basic rating life calculation. The life and adopted a correction coefficient calculation method of the bearing lubrication, pollution and material fatigue limit count.



ISO 281:1990 / Amd then also allows bearing manufacturers recommend the appropriate method, to calculate according to the operating conditions of the available bearing life correction coefficient. Correction coefficient aSKF SKF bearing adopts the concept of fatigue load limit Pu, similar to other algorithm of machine parts. The value of the fatigue load limit is shown in the list of products. In addition, the correction coefficient aSKF bearings SKF bearing life also USES the lubricating condition (viscosity ratio) and a coefficient eta c said pollution levels to reflect the operating conditions of use.