The inner ring of the FAG spherical roller bearing used in the paper machine was found to be damaged by the envelope detection method. Spectrum of envelope signal between 0 and 200 Hz, bottom: intact bearing; top: damaged bearing nIR inner ring speed [min1] fIR inner ring signal frequency (cycle frequency) [Hz] 6: found by envelope detection The inner ring of the spherical roller bearing on the paper machine is damaged. 0 4 8 12 16 20 min 24 The relationship between temperature change and vibration value and lubrication stop time. FAG spindle bearing B7216E.TPA; P/C u003d 0.1; n u003d 9000 min1; fatigue damage of lubricant ISO VG100. Bearings in point contact (ball bearings) are the simplest; for roller bearings, damage can be reliably found using complex evaluation procedures such as envelope circle detection. However, this monitoring method is not suitable for observing lubrication conditions. As mentioned above, problems with the lubrication supply can be detected by temperature detection. Figure 7 shows this nicely. Vibration values u200bu200bare nowhere near as sensitive as temperature sensors. Therefore, if conditions permit, it is ideal to complement each other with temperature measurement and vibration measurement. 8: Development of fatigue damage of inner ring raceway of angular contact ball bearings. The time period for inspection from the onset of failure is given as a percentage of the nominal life L10. Emergency Bearing Replacement Program Remaining Life Once bearing damage is detected, the consequent question is whether the bearing should be replaced immediately or can continue to be used until the next scheduled machine downtime. There are several bearing conditions that must be considered before making a decision. For example, bearing damage may reduce the working accuracy of the machine tool, so the urgency of bearing replacement first considers how long the parts without quality defects can continue to be produced. Of course, due to the interruption of the oil supply system, the bearing suddenly locks due to overheating at high speed, and the bearing must be replaced immediately. In many cases, the machine can continue to operate without production quality issues despite bearing damage. How long it will last is related to bearing load, speed, lubrication and lubricant cleanliness. A large number of failure propagation tests under various loads have been carried out on ball bearings. Fatigue growth is slow under moderate loads, so bearing replacement is generally not required until the next expected downtime. Fatigue develops rapidly as the load increases. The fatigue starts to expand slowly, but as the fatigue area increases, the fatigue accelerates. Figure 8 (page 7), Figure 9 and Figure 10 show these findings. 9: The relationship between the size of the damaged area and the running time after the failure (when about 0.1 % of the circumferential track is peeled off) The remaining operating time is based on the relationship of stress conditions. Operating conditions before the first signs of fatigue failure: Elastohydrodynamic lubrication at its cleanest.