Bearings exhibit strong regularity and excellent repeatability during their use. Normal high-quality bearings (bearings) have relatively low vibration and noise at the beginning of use, but the spectrum is somewhat scattered and the amplitude is small, which may be due to some defects in the manufacturing process, such as surface burrs.

After exercising for a period of time, the vibration and noise maintain a certain level, and the spectrum is very single, with only one or two harmonics appearing. It is rare to see a frequency spectrum that is three times higher than the power frequency, and the bearing state is very stable, entering a stable working period.

After continuing to operate and entering the later stage of use, the vibration and noise of the bearing begin to increase, sometimes producing abnormal sounds, but the increase in vibration changes slowly. At this point, the kurtosis value of the bearing suddenly reaches a certain value. We believe that at this point, the bearing is exhibiting initial failure.

At this point, it is required to closely monitor the bearing and pay close attention to its changes. Afterwards, the kurtosis value of the bearing began to rapidly decrease and approach the normal value, while the vibration and noise began to significantly increase, and the amplitude of the increase began to accelerate. When the vibration exceeded the vibration standard (such as ISO2372 standard), the kurtosis value of the bearing also began to rapidly increase. When both the vibration standard and the kurtosis value exceeded the normal value (using kurtosis relative standard), we believe that the bearing has entered the late stage of fault production and requires timely maintenance of the equipment, Replace bearings.

The bearing exhibits late stage fault characteristics and usually takes no more than one week for serious faults (such as bearing damage such as shaft holding, burns, sand frame cracking, raceway wear, bead wear, etc.) to occur. The larger the equipment capacity, the faster the speed, and the shorter the interval time. Therefore, in actual bearing fault diagnosis, once late stage fault characteristics are discovered, it is necessary to decisively determine the presence of bearing faults and arrange maintenance as soon as possible.

The usage factors mainly refer to whether the installation, adjustment, maintenance, and repair meet the technical requirements. According to the technical requirements for bearing installation, use, maintenance, and upkeep, monitor and inspect the load, speed, working temperature, vibration, noise, and lubrication conditions of the running bearings. If any abnormalities are found, immediately identify the cause and make adjustments to restore normal operation. Installation conditions are one of the primary factors in use. Improper installation of bearings often leads to changes in the stress state between the various parts of the entire bearing, causing the bearing to operate abnormally and end its service life prematurely

The internal factors mainly refer to the three major factors that determine the quality of bearings, including structural design, manufacturing process, and material quality.

The metallurgical quality of bearing materials was once the main factor affecting the early failure of bearings. With the advancement of metallurgical technology, such as vacuum degassing of bearing steel, the quality of raw materials has been improved. The proportion of raw material quality factors in bearing failure analysis has significantly decreased, but it remains one of the main influencing factors of bearing failure. Proper material selection is still a factor that must be considered in bearing failure analysis.

The manufacturing of bearings generally involves multiple processing steps such as forging, heat treatment, turning, grinding, and assembly. The rationality, progressiveness and stability of each processing technology will also affect the service life of bearings. The heat treatment and grinding processes that affect the quality of finished bearings are often more directly related to the failure of bearings. In recent years, research on the deterioration layer on the working surface of bearings has shown a close relationship between grinding technology and bearing surface quality.

The main task of bearing service life analysis is to identify the main factors causing bearing failure based on a large amount of background materials, analysis data, and failure forms, in order to propose targeted improvement measures, extend the service life of bearings, and avoid sudden early failure of bearings.