How to correctly judge the running law and fault of rolling bearing

The rolling bearing shows strong regularity during its use, and the repeatability is very good. Normal high-quality bearings (rolling bearings) at the beginning of use, vibration and noise are relatively small, but the spectrum is somewhat scattered, the amplitude is small, may be due to some defects in the manufacturing process, such as surface burrs caused.

After a period of movement, vibration and noise to maintain a certain level, the spectrum is very single, only 1. double frequency. Rarely appear more than three times the frequency spectrum, the bearing state is very stable, into a stable working period. After continuing to run into the later stage of use, the vibration and noise of the rolling bearing begin to increase, sometimes abnormal sound occurs, but the change of vibration increase is relatively slow, at this time, the bearing kurtosis value begins to suddenly reach a certain value.

We believe that at this time, the rolling bearing is manifested as an initial failure. At this time, it is necessary to closely monitor the rolling bearing and pay close attention to its changes. After that, the bearing kurtosis value began to decrease rapidly and approached the normal value, while the vibration and noise began to increase significantly and its increasing amplitude began to accelerate. When the vibration exceeded the vibration standard (such as the ISO2372 standard), the bearing kurtosis value also began to increase rapidly. When both the vibration standard and the kurtosis value also exceeded the normal value (available kurtosis relative standard), we believe that the bearing has entered the late failure stage, it is necessary to repair the equipment and replace the rolling bearing in time.

Rolling bearings show late fault characteristics to the occurrence of serious failure (generally bearing damage such as shaft holding, burns, sand spalling, raceway, bead wear, etc.) time is not more than one week, the larger the equipment capacity, the faster the speed, the shorter the interval time. Therefore, in the actual rolling bearing fault diagnosis, once the late fault characteristics are found, the bearing fault should be judged decisively and the maintenance should be arranged as soon as possible.