In actual production, condition monitoring and fault diagnosis of rolling bearing is an important link in equipment maintenance and management. Because its rolling bearing is widely used in equipment, the state of rolling bearing is directly related to the operation state of rotating equipment, especially in continuous large-scale production enterprises, it is widely used in important parts of large-scale rotating equipment. After long-term practice and exploration, some practical skills of practical fault diagnosis of rolling bearing have been accumulated.
In practice, attention should be paid to the selection of measuring point location and acquisition method. In order to truly and accurately reflect the vibration state of the rolling bearing, it is necessary to pay attention to the accuracy and authenticity of the collected signals. Therefore, the measuring points shall be arranged near the bearing. There is generally a rear fan cover at the free end of the motor, and the measuring points shall be selected in the fixing screws of the fan cover, which has a good monitoring effect. In addition, attention must be paid to the multiple acquisition and analysis of vibration signals for comprehensive comparison. To get an accurate conclusion.
In the long-term production condition monitoring, we found that the rolling bearing showed a strong regularity and good repeatability in its use. When the normal high-quality bearing is put into use, the vibration and noise are relatively small, but the spectrum is scattered and the amplitude is small, which may be caused by some defects in the manufacturing process, such as surface burrs. After a period of movement, the vibration and noise maintain a certain level, and the spectrum is very single, only one or two times the frequency. The frequency spectrum above three times of power frequency rarely appears, and the bearing state is very stable and enters the stable working period.
After continuous operation, in the later stage of use, the bearing vibration and noise begin to increase, and sometimes abnormal sound occurs, but the change of vibration increase is slow. At this time, the bearing kurtosis value begins to suddenly reach a certain value. At this time, the bearing shows initial failure. At this time, it is required to closely monitor the bearing and pay close attention to its changes. Thereafter, the bearing kurtosis value begins to decrease rapidly and approaches the normal value, while the vibration and noise begin to increase significantly, and the increase amplitude begins to accelerate. When the vibration exceeds the vibration standard (such as ISO2372 standard), the bearing kurtosis value also begins to increase rapidly.
When both the vibration standard and the kurtosis value exceed the normal value (kurtosis relative standard can be used), It is considered that the bearing has entered the late fault production, so it is necessary to repair the equipment and replace the rolling bearing in time. The bearing shows the characteristics of late fault. The time from the occurrence of serious fault (generally bearing damage, such as shaft holding, burn, sand frame spalling, raceway, bead wear, etc.) is mostly less than one week. The larger the equipment capacity, the faster the speed, and the shorter the interval. Therefore, in the actual rolling bearing fault diagnosis, once the late fault characteristics are found, the bearing fault should be determined and the maintenance should be arranged as soon as possible.