Improper handling of vibration affecting the stable operation of SKF high temperature bearings


Grease lubrication has a sealing method of pre-filling […]

Grease lubrication has a sealing method of pre-filling the sealed bearing with grease, and a filling method of filling an appropriate amount of grease inside the housing, and refilling or replacing it at regular intervals. In addition, for machines with multiple high-temperature bearings that need to be lubricated, a centralized grease supply method in which pipes are connected to each lubrication point is also used. Grease lubrication can be filled with grease for a long time without replenishment, and the structure of the sealing device is relatively simple, so it is widely used. Oil lubrication is relatively simple. Frequent lubrication can increase the service life of SKF bearings.


Imported bearings are allowed to have a slight running noise during work. If the noise is too loud or there is abnormal noise or impact, it indicates that the bearing is faulty.

The causes of noise produced by rolling bearings are more complicated. One is the wear of the mating surfaces of the inner and outer rings of the bearing. Due to this kind of wear, the matching relationship between the bearing and the housing, the high-temperature bearing and the shaft is destroyed, causing the axis to deviate from the correct position, causing abnormal noise when the shaft is moving at high speed. When SKF bearings are fatigued, the metal on the surface will peel off, which will also increase the radial clearance of the bearing and produce abnormal noise. In addition, insufficient bearing lubrication, formation of dry friction, and bearing breakage will cause abnormal noise. After the bearing is worn loose, the cage is loose and damaged, and abnormal noise will also be produced.


When the mechanism is running, the location where the bearing is installed is allowed to have a certain temperature. When touching the housing of the mechanism with your hand, it should be normal that you do not feel hot, otherwise it indicates that the bearing temperature is too high.


The reasons for the excessively high bearing temperature include: the quality of lubricating oil does not meet the requirements or deterioration, the viscosity of lubricating oil is too high; the mechanism assembly is too tight (insufficient clearance); the SKF bearing assembly is too tight; the bearing race is rotating on the shaft or in the housing; Too large; the bearing cage or rolling elements are broken, etc.


Selection and control of tolerances of shaft and bearing chamber: After the bearing is pressed into the bearing, it should rotate flexibly without any sense of blocking. If there is obvious inflexible rotation, it indicates that the size of the shaft is too large and the tolerance needs to be lowered. If the high temperature bearing is pressed into the shaft and turned by hand, there is an obvious sense of "sand", it may be that the tolerance of the shaft is too large or the roundness of the shaft is not good. Therefore, when controlling the tolerance of the shaft and the bearing chamber, the roundness must be controlled. At present, many domestic manufacturers only control the tolerance, but not the roundness.


Because SKF bearings are high-precision products, improper assembly can easily damage the bearing raceway and cause bearing damage. When assembling the bearing, there should be a special mold, which can not be knocked at will. When pressing into the shaft, only a small circle can be stressed, and a large circle can only be stressed. When assembling, it is required to use air pressure or hydraulic pressure. When pressing, the upper and lower touch should be outside the horizontal state. If there is a tilt, the bearing channel will be damaged due to the force, and the bearing will produce noise. In the past, many manufacturers thought it was a bearing problem. After our constant publicity, now the motor factory has realized that the problem is mainly the insulating paint. This problem is mainly because the acidic substance volatilized from the insulating paint forms corrosive substances at a certain temperature and humidity, which causes bearing damage after corroding the high-temperature bearing groove. At present, the problem can only be to choose a good insulating paint, and ventilate for a period of time after drying and assembly.

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