As a whole, bearing many parts, any failure, are declared bearing failure, that is, “can not be used”. So for different bearing parts, we have: Rolling body and ring: Bearing life usually refers to fatigue life. Fatigue is related to the load and speed of bearings. Therefore, the life of the rolling body and raceway of the bearing is affected by the bearing load and speed, and different loads and different speeds lead to different bearing life. Of course, mechanical engineers can see the relevant factors from the bearing life calculation. Here with a very simple example can explain: a bearing, with hand disk (equivalent to no load, low speed), is almost impossible to be broken, that is, its life is very, very long (close to infinite). But the same bearing, given a large load, running at a high speed, may soon fail. Therefore, in order to roughly estimate the fatigue life of bearings, we need to consider the load and speed, and simply ask “how long can the bearing be used” is unable to give the answer. Cage: The cage is subjected to reciprocating force inside the bearing, and fatigue will also occur under normal circumstances. At the same time, when the working condition changes, the cage will also be subjected to additional load. But under normal circumstances, the cage load compared with the roller and raceway, will be much smaller. Therefore, under normal circumstances, the fatigue life of the cage will exceed the bearing. (Abnormal conditions require additional consideration.) In addition, the cage of different materials will also be affected by the environmental temperature, so it is not expanded here. Seal: If the non-contact dustproof cover, the general dustproof cover does not bear any load. The fatigue life can be considered almost infinite (except for abnormal conditions). However, if the chemical reaction between the dust cover and the external environment, pollutants, etc. (such as slow oxidation, etc.) is taken into account, additional evaluation is also needed. For contact seal, the general seal material is rubber material. The life of the seal here is affected by the wear of the lip, as well as the chemical reaction (such as slow oxidation) between the seal material itself and the external environment and pollutants. The wear of the sealing lip is related to the compression force and relative moving speed of the lip and the anti-wear performance of the sealing material itself. Seal manufacturers should have relevant test data. Lubrication: Rolling bearings are generally used for grease lubrication, and the life of grease can be estimated according to the life of general grease. Interested readers can refer to “Motor Bearing Application Technology”, “Motor Bearing Fault Diagnosis and Analysis” and other related books for calculation. In addition, static (non-operating state) grease will also be affected by air oxidation, need to check with the relevant manufacturer.