Immediate downtime due to the failure of the bearing model itself is rare, such as due to installation errors or lack of lubrication. According to the operating conditions, it may take several minutes for the bearing to fail from the beginning to the actual failure, and in some cases it may take several months. When selecting the type of bearing monitoring, the application of the bearing and the consequences of failure when the bearing is running on the equipment should be used as the basis for the gradual deterioration of the condition. . 1.1 Subjective identification failure In most bearing applications, if the operator finds that the bearing system is not running smoothly or has abnormal noise, it can be judged that the bearing has been damaged, as shown in Table 1. Use technical equipment for bearing monitoring. When a bearing failure will cause a dangerous event or cause a long-term shutdown, accurate and long-term monitoring of the bearing's operation is required. Take engine turbines and paper machines as examples. In order to make monitoring reliable, it must be selected based on the expected failure type. Sufficient and clean lubricant is the main prerequisite for worry-free operation. The following methods can be used to detect undesirable changes: monitor the supply of lubricant, measure the oil pressure, measure the oil flow, detect the abrasive particles in the lubricant, regularly sample, use an electromagnetic probe to perform spectral analysis in the laboratory, and continuously sample the electromagnetic signal transmitter through a particle counter Continuous on-line detection of the number of particles flowing to measure the temperature. Generally, thermocouple 41 is used. Abnormal operation means failure. 1: Failure of the ring or rolling element found by the operator. Motor vehicle wheel amplitude increases. Inclination clearance increases. Guidance system Vibration saw: more shock and vibration at the connecting rod, reduced work accuracy due to pollution or insufficient lubrication, damage to the wear ring or rolling element, clearance or preload Change lathe: further development of the vibration pattern of the workpiece Cold rolling: cold-rolled material Periodic surface defects, such as tensile deformation, segregation streamlines, etc. Unusual operating noise: Rumble or irregular noise, horse hissing or humming noise, gradual changes in operating noise, excessive clearance, damage to the contact surface, pollution, unsuitable lubricants, damage to the operation due to changes in working clearance caused by temperature rise Surface (for example, due to pollution or fatigue) motor gear (because it is always submerged by the noise of the gear, so the noise of the bearing is difficult to identify) 2: The temperature change of the spindle bearing of the machine tool. Test conditions: n · dm u003d 750 000 min1 · mm. 3: The temperature change of the disturbed floating bearing. Test conditions: n · dm u003d 750 000 min1 · mm. By measuring the temperature, it is possible to reliably and relatively simply detect the bearing failure caused by insufficient lubrication. Conventional temperature characteristics: A stable temperature can be reached during smooth operation, as shown in Figure 2. Abnormal characteristics: The sudden increase in temperature may be caused by lack of lubrication or radial or axial overload of the bearing, see Figure 3. Unsteady temperature changes and continuous rise in temperature are usually due to deterioration of lubrication conditions, such as reaching the end of the grease life, see Figure 4. However, it is not appropriate to use the method of measuring temperature to judge the initial damage there, such as fatigue. 4: When the grease fails, the relationship between temperature change and time. Test conditions: n · dm u003d 200 000 min1 · mm. Partial damage of the bearing, such as dents, static corrosion or fracture caused by the rolling elements, can be detected in time through vibration measurement. The path, velocity, and acceleration sensors record the vibration waves caused by the pits under cyclic motion. These signals can be further processed in different ways, depending on the operating conditions and the expected credibility. The most common ones are: Measuring effective value Measuring vibration value Signal analysis experience through envelope detection shows that the latter is more reliable and applicable. With a special signal processing method, even damaged bearing parts can be found, as shown in Figures 5 and 6. For more information, please refer to our TI No. WL 80-63 'Diagnosing Rolling Bearings with a Bearing Analyzer'.