The service life of the bearing has been tested before leaving the factory. However, due to the different environment or method of use, the service life of the bearing is different from the actual one. Some bearings have problems before they reach their service life, so they have to be replaced in advance. Today, the editor will introduce to you what kind of fault conditions require bearing replacement.
There are special mathematical formulas for the calculation of the fault frequency of these bearings, but it is troublesome in practical work. The more convenient method is to use special software. As long as the information of bearing model and manufacturer is input, the corresponding fault frequency of various bearings can be obtained. On the whole, the fault frequency precursors can be analyzed by the following conditions:
Four stages of rolling bearing failure frequency:
The first stage is the embryonic stage when the bearing begins to fail. At this time, the temperature is normal, the noise is normal, the total amount and spectrum of vibration speed are normal, but the total amount and spectrum of peak energy have signs, reflecting the initial stage of bearing failure. At this time, the real bearing fault frequency occurs in the ultrasonic section of about 20-60khz.
In the second stage, the temperature is normal, the noise increases slightly, the total amount of vibration speed increases slightly, and the change of vibration spectrum is not obvious, but the peak energy increases greatly, and the spectrum is more prominent. At this time, the bearing fault frequency occurs in the range of about 500hz-2khz.
In the third stage, the temperature rises slightly, the noise can be heard, and the total vibration speed increases greatly, and the bearing fault frequency and its harmonics and sidebands are clearly visible in the vibration speed spectrum. In addition, the noise level in the vibration speed spectrum increases significantly, and the total peak energy becomes larger and the spectrum is more prominent than that in the second stage. At this time, the bearing fault frequency appears in the range of about 0-1khz. It is suggested to replace the bearing at the later stage of the third stage. At this time, the rolling bearing fault features such as wear visible to the naked eye should have appeared.
In the fourth stage, the temperature increased significantly, the noise intensity changed significantly, the total vibration speed and the total vibration displacement increased significantly, and the bearing fault frequency on the vibration speed spectrum began to disappear, which was replaced by a larger random broadband high-frequency noise; The total peak energy increases rapidly, and some unstable changes may occur. Never let the bearing run in the fourth stage of fault development, otherwise catastrophic damage may occur.
According to the research results, the whole service life of the general rolling bearing is from the time when the bearing is installed and put into use, before it > Within 80% of the service life, the bearing is normal. And then corresponding to the development of rolling bearing fault, its remaining life in the first stage is 10% ～ > 20% L10, 5% - 10% L10 in the second stage, 1% - 5% L10 in the third stage, and about 1H or 1% L10 in the fourth stage.
Therefore, when facing bearing problems in actual work, considering the unpredictable sudden harm of the fourth stage of bearing fault development, it is recommended to replace the bearing at the later stage of the third stage, which can not only avoid the expansion of the fault and the occurrence of more serious accidents, but also ensure the service life of the rolling bearing as much as possible, and according to the visible wear and tear on the bearing at this time The failure characteristics of rolling bearings such as parts damage are quite convincing.
As for the identification in the later stage of the third stage of bearing fault development, it is necessary to comprehensively consider the above theoretical characteristics in combination with the actual temperature, noise, velocity spectrum, peak energy spectrum, total trend of velocity and peak energy and actual experience.
