Basic performance requirements for monitoring the working status of rolling bearings
1. Requirements for monitoring rolling bearings using magnetic plugs
(1) Magnetic plugs are only suitable for monitoring critical main bearings lubricated with oil and returned through dedicated pipelines.
(2) The magnetic plug should be installed as close as possible to the main bearing being monitored, on the main channel for oil return, without the obstruction of a filter screen, oil pump, or other hydraulic components in the middle.
(3) In order to improve monitoring efficiency, a rotary oil storage tank with return oil inlet and outlet can be made. The oil reservoir should be designed in an inverted conical table shape, and the magnetic plug should be installed at the bottom of the oil reservoir. The oil inlet of the oil reservoir should be tilted at a certain angle to allow lubricating oil to enter from the tangential direction. This is beneficial for the separation of abrasive particles from the lubricating oil that circulates, settling at the bottom, entering the magnetic plug through small holes, and adsorbing on the end of the magnetic steel.
2. Morphological characteristics of wear particles under normal conditions
During the running in and normal operation periods of rolling bearings, the size of the abrasive fragments produced is generally 0.01-0.015mm, mixed with some metal powder. The number of abrasive particles generated by the new bearing during the running in period is higher than that during the normal operating period. After entering the normal operating period, the number of abrasive particles and metal powder will significantly decrease. The abrasive fragments appear in a thin and short shape under a microscope, with irregular cross-sections.
3. Morphological characteristics of faulty wear 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 appear in the form of roughly circular, radially separated rose petals; The abrasive debris in the raceway presents a roughly circular surface fragmentation form; The roller abrasive debris of roller bearings usually presents in a curled rectangular shape with a length equal to 2-3 times the width; The abrasive debris on the raceway generally presents an irregular rectangular shape.
The basic performance requirements of rolling bearings for materials depend on the working characteristics of the bearings. Generally speaking, imported bearing steel should have the following properties:
1) High contact fatigue strength.
2) High wear resistance.
3) High elastic limit and yield strength.
4) High and uniform hardness.
5) A certain impact toughness.
6) Good dimensional stability.
7) Good corrosion inhibition performance.
8) Good process performance.
For bearing materials working under special conditions, they should also have special properties that are suitable for their specific requirements, such as high temperature resistance, low temperature resistance, corrosion resistance, radiation resistance, and anti magnetic properties.