Monitoring of rolling bearings using magnetic plug method:
1. Requirements for monitoring rolling bearings using magnetic plugs
(1) Magnetic plugs are only suitable for monitoring critical main bearings that are lubricated with oil and return oil through dedicated pipelines.
(2) The magnetic plug should be installed as close as possible to the monitored main bearing, on the main oil return channel, without any barriers from filters, oil pumps, or other hydraulic components in the middle.
(3) To improve monitoring efficiency, a rotary oil storage container with return oil inlet and outlet can be made. The oil storage container should be made in the shape of an inverted cone, and the magnetic plug should be installed at the bottom of the oil storage container. The inlet of the oil reservoir should be tilted at a certain angle to allow lubricating oil to enter it from the tangential direction. This is beneficial for the separation of abrasive particles from the swirling lubricating oil, which settles at the bottom and enters the magnetic plug through small holes, adsorbing on the end of the magnetic steel.
2. Under normal circumstances, the morphological characteristics of wear and tear particles
During the running in period and normal operation period of rolling bearings, the size of the abrasive particles generated is generally 0.01-0.015mm, mixed with some metal powder. The number of abrasive fragments generated during the running in period of new bearings is higher than that during normal operation. After entering the normal operation period, the number of abrasive fragments and metal powder will significantly decrease. The abrasive fragments appear fine and short in shape under the microscope, with irregular cross-sections.
3. Morphological characteristics of faulty wear abrasive particles
The main failure mode of rolling bearings is fatigue pitting. The size of abrasive fragments formed by rolling fatigue and peeling is generally 0.025-0.05mm. Sometimes there are larger fragments mixed with some metal powder. The steel ball abrasive fragments of ball bearings usually take the form of roughly circular, radially separated rose petals; The abrasive particles on the raceway present a roughly circular surface broken form; The roller abrasive fragments of roller bearings usually take the form of curled rectangular shapes with a length equal to 2-3 times the width; The abrasive fragments on the raceway generally appear as irregular rectangles.
Issues to be noted when monitoring rolling bearings using temperature measurement method:
By measuring the temperature rise during bearing operation, it is generally difficult to monitor local damage such as fatigue peeling, cracks, or indentations in rolling bearings, especially in the early stages of damage where it is almost impossible to detect any problems. When the temperature of the bearing rises after long-term normal operation, the problem reflected is generally not only serious, but also rapidly develops, causing bearing damage and failure. At this point, intermittent monitoring often leads to missed monitoring situations. If the temperature of the bearing exceeds 70-80 ℃ during monitoring, the machine should be stopped immediately for inspection.
For newly installed or readjusted rolling bearings, monitoring their temperature rise within a specified time using temperature measurement method can determine the quality of the bearing installation and adjustment, especially when the clearance is too tight, which may result in excessive temperature rise. Timely adjustment upon discovering problems is beneficial for extending the service life of rolling bearings.

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