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Press in method is often used for assembly. The simple method is to use a copper rod and a hammer to knock the bearing race with interference fit symmetrically in a certain order to make the bearing press in smoothly. In addition, soft metal casing can also be driven by hand hammer or press. If the operation is improper, the seat ring will be deformed and cracked, or the hammer will hit the seat ring with non interference fit, and the raceway and Koyo bearing body will be indented or the bearing will be damaged indirectly.
During assembly of Koyo bearing, if its interference with shaft diameter is large, it is generally assembled by hot assembly method. Put the bearing into the oil barrel containing engine oil, and heat the outside of the oil barrel with hot water or flame. The process requires that the heated oil temperature be controlled at 80 ℃ ~ 90 ℃, generally not more than 100 ℃, and mostly not more than 120 ℃. After the bearing is heated, it shall be quickly taken out and sleeved on the journal. If the heating temperature is too high due to improper temperature control, the bearing will be tempered and the hardness will be reduced, and the bearing will be easy to wear, peel off and even crack during operation.
It can be seen from the above that the axial clearance of Koyo bearings with adjustable or non adjustable clearance shall be adjusted during assembly (but some bearings with non adjustable clearance do not need to leave axial clearance) to compensate for the thermal elongation of the shaft when the temperature rises, so as to ensure the normal operation of Koyo bearing body. If the axial clearance is too small, it will make the bearing difficult to rotate, heat, and even make the Koyo bearing body stuck or damaged; If the axial clearance is too large, it will cause abnormal sound during operation, and even cause serious vibration or damage to the cage.
The input shaft of most operating equipment is connected with the power shaft through the coupling, so the coupling must be aligned during assembly to make the driving shaft and the driven shaft on the same axis. Poor lubrication. The lubricating oil (or grease) used in Koyo bearings has a certain working temperature. When the temperature is too high, it will deteriorate, thus losing its lubricating effect and burning the bearings due to high temperature. In addition, poor quality of lubricating oil (or grease) itself or untimely refueling (grease) during operation will also cause bearing temperature rise or abnormal sound.
Rotor imbalance generally speaking, the rotor of operating equipment shall be subject to action and static balance before assembly, so there will be no problem with the bearing. However, during the operation of some rotors, due to the corrosion of media or the wear of solid impurities, or the bending of the shaft, unbalanced centrifugal force will be generated, resulting in bearing heating, vibration, serious wear of raceway and even damage. If the inspection and replacement are not timely, the bearing shall be inspected regularly according to the regulations during operation.
In case of heating, abnormal sound, vibration, etc., the bearing shall be stopped in time to find the cause and eliminate the fault. If serious fatigue peeling, oxidation corrosion, worn pits, cracks and hardness drop to HRC < 60, or there is too much noise to be adjusted, the bearing shall be replaced in time. If the inspection and replacement are not timely, it will cause serious damage to the bearing and even the rotor, thus affecting the normal production. In addition, vibration caused by improper bearing disassembly and loose equipment anchor bolts will also lead to indentation of Koyo bearing raceway and rolling element and cracking of inner and outer race of bearing.
(1) When replacing the bearing, carefully check the new bearing, and carefully check the shaft diameter, bearing seat hole and rotor;
(2) When assembling and disassembling the bearing, strictly implement the maintenance process and operate carefully to avoid bearing damage caused by improper assembly and disassembly;
(3) Refuel and change the oil on time to ensure that the working condition of the bearing is always in good condition;
(4) Check carefully during operation and eliminate hidden troubles in time.