Four phases of rolling bearing failure

The deteriorating development of the rolling bearing is not a linear process, but a process index. In different degradation stages, within the scope of fault information in different frequency band, so should use different methods of fault detection. The industry is generally accepted that the degradation course of rolling bearing can be divided into four stages. Figure 1 illustrates a typical bearing fault development phase 1 - — Bearing failure early bearing at this stage in the first time the surface microscopic cracks or lattice mismatch, while bearing surface can't see the crack or small spalling, the vibration signal not obvious impact to low frequency signal, using traditional acceleration sensor can't pick up the fault signal, but The Times or micro crack on the surface of the lattice mismatch will produce acoustic emission signals or stress wave signal. Therefore, at this stage of bearing fault characteristic mainly reflects in the ultrasonic frequency, can through the acoustic emission sensor to pick up or acceleration sensor based on resonance, its main performance for the measured signal peak or energy. Figure 2 bearing vibration signal characteristics of degradation stage 1 phase 2 - — Bearing failure stage at this stage the bearing of the micro degradation started from surface to surface extension, and the bearing contact surface crack or small spalling damage point. When surface and the damage point contact bearing components, can form a certain frequency of shock pulse, based on Fourier transform, the short-term impact of the signal in frequency domain is a broadband signal, so the impact signal will inevitably provoke bearing parts of high-frequency inherent frequency resonance occurs, so that the vibration strengthening, through the acceleration sensor can pick up to this part of the signal, using envelope demodulation technique could observe bearing fault characteristic frequency, at the end of phase 2 can also observe the frequency doubling fault characteristic frequency. At this stage, bearing fault characteristic frequency temporary submerged in high to low frequency noise, so the fault characteristic frequency observation clear fault characteristic frequency. Figure 3 bearing vibration signal characteristics of degradation stage 2 stage 3 - — Bearing failure rapid development at this stage, with the accelerating development of bearing damage, damage to the impact of the bearing contact surface is more and more intense, in the bearing fault characteristic frequency of resonance frequency demodulation frequency doubling of more and more, and the size of cyclical impact energy was enough to directly observed through the power spectrum of vibration signals, this time can be directly in the clear on the power spectrum of bearing vibration signals of the fault characteristic frequency, and the trend of frequency doubling, more and more. Figure 4 bearing vibration signal characteristics of degradation stage 3 phase 4 - — Bearing failure at this stage, the end of rolling bearing has nearly reached the end of life, injury point can be seen by the naked eye, bearing movement become particularly large noise, temperature rise sharply. At this point directly on the power spectrum can not only clear bearing fault characteristic frequency and the frequency doubling, if damage points alternately into the load zone, also can see obvious beside the fault characteristic frequency modulation frequency. In the fourth stage of the end of the spectrum lines become is not very clear, will form a bulge in the power spectrum 'thatched heap', also the high frequency vibration energy in also may not rise but lower at this moment, if it is found that the high frequency of monitoring quantity began to decline, not on the surface of bearing condition better, but that the end of the bearing is close to the life. Figure 5 bearing vibration signal characteristics of degradation stage 4