What to do if the bearing temperature is too high during use?
The bearing temperature is too high during use, which is similar to the abnormal situation of "fever". It is a common and harmful fault in various equipment. If the cause is unknown and the treatment is improper, it will reduce the service life of the bearing, increase the maintenance cost, and even cause the bearing to burn out. Therefore, it is necessary to quickly determine the cause of the high temperature and take appropriate measures to solve it, which is the guarantee for the continuous and safe operation of the equipment. There are many reasons for the excessive temperature of the bearing. The common problems are as follows.
(1) Poor lubrication. Lubrication has an important influence on the friction, wear, vibration, etc. of the bearing. Good lubrication is a necessary condition to ensure the normal operation of the bearing. According to statistics, about 40% of bearing damage is related to poor lubrication. The main effects of lubrication on bearings include: reducing friction and wear, preventing metal corrosion, preventing foreign matter from intruding, playing a sealing role, discharging friction heat, preventing the bearing temperature from rising too high, and extending the service life of the bearing.
The longer the bearing runs, the better the quality, but this is also closely related to the lubricant. Common factors that cause poor bearing lubrication include: ① insufficient lubricant (grease or oil); ② the lubricating oil pipe is blocked by foreign matter; ③ the quality of the lubricant (grease or oil) is problematic; ④ the lubricant (grease or oil) is not added on time; ⑤ the lubricant (grease or oil) contains impurities, etc. These factors will cause the bearing temperature to rise or wear out prematurely during use.
(2) Improper installation. Improper installation is another important reason for bearing heating. Because the correctness of bearing installation has a direct impact on its life and the accuracy of the main machine, the center line of the shaft and the bearing hole should coincide during installation. If the bearing is not installed correctly, the accuracy is low, and the deviation between the bearing rotation center and the hole axis center is large, a torque will be generated during rotation, causing the bearing to heat up, wear or the cage to get stuck. In addition, improper bearing installation will also generate vibration and abnormal noise, and will also increase the temperature rise.
(3) Insufficient cooling. Insufficient cooling is usually manifested as pipe blockage, improper cooler selection or installation, poor cooling effect, etc. If the cooler is blocked by scale on the lubrication pipeline, the cooling effect will be poor, especially in summer production. The more effective treatment method is to descale the cooler before summer every year.
(4) Inspection and replacement are not timely. If the bearing is found to be seriously fatigued, peeled, rusted, worn, cracked, or has too much noise and cannot be adjusted, if it is not replaced in time, it will cause the bearing to heat up, make abnormal noise, vibrate, etc., thus affecting normal production.
(5) Bearing fit. When installing the bearing, the fit between the inner diameter of the bearing and the shaft, and the outer diameter and the shell is very important. When the fit is too loose, the fitting surface will produce relative sliding called running or creep. Running will cause the bearing temperature to rise in a short time and the bearing to burn; once creep occurs, it will wear the fitting surface, damage the shaft or shell, and the wear powder will invade the inside of the bearing, causing heat. When the interference between the inner and outer diameters of the bearing and the hole shaft and the fitting surface is too large, the outer diameter of the outer ring will become smaller or the inner diameter of the inner ring will become larger, reducing the internal clearance of the bearing. Too small a clearance will cause the bearing to heat up during operation and damage the bearing. When the interference is too large, the inner ring of the bearing will also crack.
(6) Improper bearing selection. When selecting bearings, attention should be paid to the bearing's maximum speed and load capacity. Generally, bearings are not allowed to be used at overspeed or overload. If they work under the conditions of maximum speed and overload, the bearing temperature will increase and the bearing service life will be shortened, which is not worth the loss.