Periodic overhaul of equipment, operation inspection and inspection of bearings removed during replacement of peripheral parts are carried out to determine whether they can be reused or whether they are in good or bad use.
At the initial stage, the noise is normal, the temperature is normal, the energy of vibration peak can be measured by ultrasound and acoustic emission. The defective outer ring of bearing and the total amount of vibration are small. There is no discrete peak of bearing fault frequency and the remaining life is more than 10%.
In the second stage, the noise increases slightly, the temperature is normal, the ultrasonic, the acoustic emission, the energy of vibration peak increases greatly, the defective outer ring of bearing, the total amount of vibration (total vibration acceleration and total vibration speed) increases slightly, the bearing fault frequency can be clearly seen in the logarithmic scale spectrum, and it is difficult to see in the linear scale spectrum, the noise level increases significantly, and the remaining life is 5%.
Stage 3, audible noise, slightly higher temperature, very high ultrasonic, acoustic emission, vibration peak energy, bearing outer ring fault, total vibration acceleration and total vibration speed have increased greatly. The spectrum of linear scale clearly shows the bearing fault frequency and its harmonic and side band, the noise level of vibration spectrum has increased significantly, and the remaining life is less than 1%.
In the fourth stage, the intensity of noise changes, temperature increases obviously, ultrasonic, acoustic emission, vibration peak energy increases rapidly, and then gradually decreases. The total fault state, vibration speed and vibration displacement of the outer bearing ring before damage significantly increase, the total vibration acceleration decreases, and the lower fault frequency of self-aligning roller bearing accounts for the dominant vibration peak. The noise level in the vibration spectrum is very high and the remaining life is less than 0.2%.