TIMKEN bearings show strong regularity and very good repeatability during their use. Normal high-quality bearings ( bearings ) have relatively small vibration and noise when they are first used, but the spectrum is a bit scattered and the amplitude is small, which may be due to some defects in the manufacturing process, such as surface burrs.
After a period of movement, the vibration and noise maintain a certain level, the spectrum is very simple, and only one or two times the frequency appear. It is rare to see a spectrum above three times the power frequency. The bearing state is very stable and enters a stable working period.
After continued operation and entering the later stage of use, the vibration and noise of the TIMKEN bearing began to increase, and sometimes abnormal noise appeared, but the vibration increase was slow. At this time, the kurtosis value of the bearing began to suddenly reach a certain value. We believe that at this time, the bearing showed an initial failure.
At this time, it is required to closely monitor the TIMKEN bearing and pay close attention to its changes. After that, the bearing kurtosis value began to drop rapidly and approached the normal value, while the vibration and noise began to increase significantly, and the increase began to accelerate. When the vibration exceeded the vibration standard ( such as ISO2372 standard ) , the bearing kurtosis value also began to increase rapidly. When it exceeded the vibration standard and the kurtosis value also exceeded the normal value ( the relative kurtosis standard can be used ) , we believe that the bearing has entered the late stage of failure and needs to repair the equipment and replace the bearing in time.
The time from when a bearing shows late-stage fault characteristics to when a serious fault occurs ( generally bearing damage such as shaft seizure, burns, sand rack spalling, raceway, bead wear, etc. ) usually does not exceed one week. The larger the equipment capacity and the faster the speed, the shorter the interval. Therefore, in actual bearing fault diagnosis, once late-stage fault characteristics are found, it should be decisively determined that the bearing is faulty and maintenance should be arranged as soon as possible.
1. The rolling sound of the bearing is checked by using a sound meter to check the size and quality of the rolling sound of the running bearing. Even if the bearing has slight damage such as peeling, it will emit abnormal and irregular sounds, which can be distinguished by a sound meter.
2. Bearing vibration Bearing vibration is very sensitive to TIMKEN bearing damage, such as peeling, indentation, rust, cracks, wear, etc., which will be reflected in the bearing vibration measurement. Therefore, the vibration size can be measured by using a special bearing vibration measuring device (frequency analyzer, etc.), and the specific abnormal situation cannot be inferred by frequency analysis. The measured values vary depending on the use conditions of the bearing or the installation position of the sensor, so it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.
3. Bearing temperature The bearing temperature can generally be inferred from the temperature outside the bearing chamber. It is more appropriate to use the oil hole to directly measure the bearing outer ring temperature. Usually, the temperature of TIMKEN bearings rises slowly as it starts to run and reaches a stable state after 1-2 hours.
