Fag bearing cage fracture belongs to accidental abnormal failure mode. Let’s analyze the causes of plastic bearing cage fracture from the following five aspects.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
1. Poor lubrication of fag bearing: the plastic bearing is in poor oil state, which is easy to form adhesive wear and deteriorate the working surface. The tear caused by adhesive wear is easy to enter the cage, resulting in abnormal load on the cage, which may lead to cage fracture.
2. Fag bearing creep phenomenon: creep mostly refers to the sliding phenomenon of the ferrule. When the interference of the mating surface is insufficient, the load point moves to the surrounding direction due to sliding, resulting in the deviation of the position of the ferrule relative to the shaft or shell to the circumferential direction.
3. Material defects of fag bearing cage: cracks, large heterometallic inclusions, shrinkage cavities, bubbles and riveting defects, lack of nails, cushion nails or the gap between the joint surfaces of two halves of cage, serious riveting injury, etc. may cause cage fracture.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
4. Abnormal load of fag bearing cage: improper installation, inclination, excessive interference, etc. are easy to reduce the clearance, aggravate the friction and heat generation, soften the surface, and premature abnormal peeling.
With the expansion of peeling, the peeling foreign matter enters the cage pocket, resulting in the operation block of the cage and additional load, aggravating the wear of the cage. Such a deteriorated cyclic effect may cause the cage to fracture.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
5. The intrusion of hard foreign matters in fag bearing, which intensifies the wear of cage and produces abnormal additional load, and may also lead to the fracture of cage.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
Grease lubrication includes the sealing method of filling grease in the sealed bearing in advance, and the filling grease supply method of filling an appropriate amount of grease in the shell and replenishing or replacing it at regular intervals. In addition, the centralized grease supply mode with pipes connected to each lubrication place is also adopted for the machinery with multiple IKO bearings that need lubrication.
Grease lubrication can be filled with grease for a long time without supplement, and the structure of its sealing device is relatively simple, so it is widely used. Oil lubrication is relatively simple. Regular lubrication can improve the service life of joint bearings.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
The imported bearing is allowed to make slight running noise during operation. If the noise is too loud or there is abnormal noise or impact sound, it indicates that the bearing is faulty.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
The causes of rolling bearing noise are complex. One is the wear of the mating surfaces of the inner and outer rings of the bearing. Due to this wear, the matching relationship between bearing and shell, IKO bearing and shaft is damaged, resulting in the axis deviation from the correct position and abnormal noise when the shaft moves at high speed.
When the joint bearing is tired, the metal on its surface will peel off, which will also increase the radial clearance of the bearing and produce abnormal noise. In addition, insufficient bearing lubrication, dry friction and bearing breakage will produce abnormal sound.
After the bearing is worn and loose, the cage is loose and damaged, which will also produce abnormal noise.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
When the mechanism is running, the part where the bearing is installed is allowed to have a certain temperature. When touching the mechanism shell by hand, it should be normal to feel that it is not hot. Otherwise, it indicates that the bearing temperature is too high.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
The reasons for high bearing temperature include: the quality of lubricating oil does not meet the requirements or deteriorates, and the viscosity of lubricating oil is too high; The mechanism assembly is too tight (insufficient clearance); The assembly of spherical plain bearing is too tight;
The bearing race rotates on the shaft or in the shell; Excessive load; Broken bearing cage or rolling element, etc.Improper treatment of Vibration Affecting the stable operation of IKO joint bearing
Selection and control of shaft and bearing housing tolerance: the bearing shall rotate flexibly without blocking feeling after being pressed into the bearing. If there is obvious inflexible rotation, it indicates that the size of the shaft is too large and the tolerance should be reduced.
If the IKO bearing rotates by hand after being pressed into the shaft, there is an obvious “rusty” feeling, 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 shaft and bearing chamber, it is also necessary to control the roundness. At present, many domestic manufacturers only control the tolerance, not the roundness.
Because the joint bearing is a high-precision product, if it is not assembled properly, it is easy to damage the bearing channel and lead to bearing damage. The bearing shall be equipped with a special mold during assembly, which cannot be knocked at will.
When pressing the shaft, only the small ring can be stressed, and when pressing the large ring, only the large ring can be stressed. Air pressure or hydraulic pressure is required during assembly. During press assembly, the upper and lower touch shall be outside the horizontal state.
If there is inclination, the bearing channel will be damaged due to stress and the bearing will produce conduction sound. In the past, many manufacturers thought it was the bearing problem. After our continuous publicity, now the motor factory has realized that the main problem is the insulating paint.
This problem is mainly because the acidic substances volatilized from the insulating paint form corrosive substances at a certain temperature and humidity, which corrodes the IKO bearing channel and leads to bearing damage. At present, the problem can only be to select good insulating paint and assemble after drying and ventilation for a period of time.