Affect the INA bearing fatigue life analysis of the failure reason

Internal factors mainly refers to the structure design, manufacturing process and material quality and so on three major factors in determining the quality of bearing. First of all, reasonable structure design and equipped with advanced, just can have a long bearing life. Bearing manufacturing generally go through forging, heat treatment, cutting, grinding and assembly, and multi-channel processing operations. The rationality of the processing technology, advanced, stability will also affect the service life of bearing. Which affects the quality of finished products bearing heat treatment and grinding process, tend to have a more direct relationship with bearing failure. In recent years the study of metamorphic layer of bearings working surface show that the grinding process and is close to the surface quality of the bearing. INA bearing materials of metallurgical quality were the main factors influencing the premature failure of the rolling bearing. As metallurgy technology, For example, the bearing steel vacuum degassing, etc. ) Progress, raw material quality is improved. Raw material quality factor in the bearing failure analysis share has declined obviously, but it is still one of the main influence factors of bearing failure. Select material adequacy is still bearing failure analysis factors must be considered. The main task of the INA bearing failure analysis, it is based on a lot of background material, analyze data and failure forms, find out the main factors of bearing failure, so that the improvement measures are put forward, prolonging bearing, avoid premature failure of the bearing of the sudden. ( 1) And the influencing factors of INA bearings fatigue life very much, can't all be estimated or through standard test conditions and to eliminate, this causes the bearing fatigue life has a great deal of actual discreteness, therefore, the fatigue life of bearing express parameters for rated L10 life, the meaning of the L10 in ISO standard of R281 clearly stipulated as follows: 'a batch of bearing enough on the same amount, the rated life L10 revolution ( Or the number of hours in at constant speed, 90% of this batch of bearing in the fatigue spalling occurring before can reach or exceed the number of revolutions ( Or hours) ”。 So far, all countries in the world to follow the rules. In some countries such as America, still use the concept of value in life. Median life LM refers to a group of INA bearings of the same values in life and means that 50% of the bearing before fatigue spalling can reach or exceed the total number of turns, or under a certain speed from time to time, the median life LM not the arithmetic mean of a batch of bearing life. Generally the median life LM is 5 times of the rated life. ( 2) , rated life concept applies only to enough of a batch of bearing, and does not apply to individual bearing. For example article 40 sets of 6204 bearing according to their use is its rated life is 1000 h without fatigue damage occurs, the rest 4 sets may be less than 1000 h would appear fatigue failure of bearing, rated fatigue life is the meaning of this batch of INA bearings in normal life play its material potential can be expected. So in most cases, users still when choosing INA bearings first as the fatigue life calculation, according to the actual failure categories, such as wear life, take the results in a smaller value for the calculation of bearing life.