Damage to bearings and monitoring during operation

In practical applications, only a portion of bearings are damaged, and the majority of bearings are used beyond the lifespan of the machine or equipment itself. Bearing damage is usually caused by wear, corrosion, seal damage, and other reasons. Generally speaking, one-third of bearing damage is fatigue damage; Another one-third of the bearing damage is due to poor lubrication; The other one-third of bearing damage is due to pollutants entering the bearings or improper installation and handling. In order to effectively eliminate problems in the application of bearings, it is necessary to analyze the causes of their symptoms, and this is also the best possible solution. The common symptoms of bearings are:

(1) The reason for "bearing overheating" is: ① incorrect selection of lubricating grease model; ② poor or excessive lubrication; ⑨ The lubricating grease contains impurities: ④ excessive load; ⑤ Insufficient bearing clearance and high friction damage caused by oil seals;

(2) The reason for "bearing noise" is: ① incorrect selection of lubricating grease model; ② Inappropriate lubrication; ③ Insufficient lubricating grease in the bearing box; ④ Inappropriate bearing clearance: ⑤ Water, acid, paint or other corrosive impurities and pollutants enter the bearing box;

(3) Bearing vibration "is caused by: ① sand particles, carbon powder or other pollutants entering the bearing box; ② Water, acid, paint or other corrosive impurities and pollutants enter the bearing box.

Bearings are the most essential rotating parts among all machines, therefore, they are the focus of our monitoring. Usually, the fault signals of bearings are judged and determined through three methods: "listening", "touching", and "observing": "noise", "temperature", and "vibration".

(1) Using listening to identify irregular operation is a common method. When the bearing emits sharp hissing, squeaking, or intermittent irregular sounds, it indicates that the bearing is in poor operating condition, and the noise varies with the speed of the bearing;

(2) Using touch to identify is also a common method. High temperature often indicates that the bearing is in an abnormal condition, and high temperature is also harmful to the bearing lubricant;

(3) Use observation method to comprehensively judge the quality of bearings.

2 Lubricating grease

In order to ensure the good and reliable operation of rolling bearings, sufficient lubrication must be applied. The main function of lubricants is to produce a thin film to separate the rotating parts of the bearing, to prevent direct metal contact between the rolling elements, raceways, and retainers, which can cause wear and corrosion of the bearing surface, reduce friction, and prevent solid and liquid contamination of the bearing. In theory, a well lubricated and ideal working condition bearing should have a lifespan of forever. However, in reality, this is not possible. But if the bearing is properly lubricated, it will achieve the longest working lifespan. Because lubricants form a layer of oil film between the sliding and rolling surfaces of bearings, even under heavy loads, direct metal contact and metal friction can be avoided. Therefore, proper lubrication and maintenance are required in various bearing applications.

Lubricating grease is the most commonly used lubricant for rolling bearings. Lubricating grease refers to a thick substance mixed with a semi fluid to solid base oil, which is a thickened mineral oil or synthetic oil. Lubricating grease is usually made of metal soap