3 motor rolling bearing disassembly
1) Disassembly of the motor rolling bearing
Several methods of disassembly for the removal of motor rolling bearings are as follows:
a. Disassemble with a puller: The puller should be of appropriate size. The claws of the puller should be fastened to the inner ring of the bearing and should not be placed on the outer ring, otherwise the bearing will be damaged. The tip of the lead screw of the puller is aligned with the center of the shaft, and the rotation is slower and the force is even.
b. Disassemble with copper rod: copper rod on the inner ring of the bearing, tap the copper rod with a hammer, knock out the bearing, and knock it evenly along the opposite sides of the inner circumference of the bearing. Don’t just knock one side, the force should not be too strong. .
c. Rest on the cylinder. Disassemble: Two iron plates are clamped under the inner ring of the bearing, resting on a cylinder (the inner diameter of the cylinder is slightly larger than the outer diameter of the rotor), and the copper block is placed on the end surface of the shaft. Hit with a hammer and focus on the center of the shaft. Put some cotton yarn in the cylinder to prevent the rotor and shaft from breaking when the bearing is removed. When the bearing is gradually loosened, the force is weakened. The bearing can also be removed from the press.
d. Heating and disassembly: If the bearing assembly is too tight or the bearing is oxidized and not easy to disassemble, the inner ring of the bearing can be heated to expand and loosen. Before heating, wrap the shaft with a damp cloth to prevent heat from spreading. Drain the oil on the inner ring of the bearing with a mechanical oil of about 100 °C. Disassemble it by the above method.
2) Installation of motor rolling bearings
Wash the original rust preventive oil (new bearing) or grease (old bearing) before installation.
The new bearing should be placed in transformer oil of 70~80 °C for about 5 minutes. After all the anti-rust oil is dissolved, take out the drip, put it in the gasoline tank, and then dry it with compressed air. After drying, add pure new grease as specified. If the bearing is not cleaned or the grease contains impurities and moisture, it will easily damage the bearing. The bearing sleeve has two methods of cold sleeve and hot sleeve on the journal. Before the set, the journal part should be wiped clean and the inner bearing cap that has been cleaned and greased should be put on.
a. Cold sleeve method: put the bearing on the shaft, align the journal, use a length of iron pipe (the inner diameter is slightly larger than the diameter of the journal, the outer diameter is slightly smaller than the outer diameter of the inner ring of the bearing), and the end of the iron pipe is placed on the bearing. On the inner ring, hammer the other end of the iron pipe and knock the bearing into it. It is best to press in with a press.
b. Hot sleeve method: the bearing is heated in transformer oil, the temperature is 80~100 °C, and the heating is 20~40min. The heating temperature should not be too high and the time should not be too long to avoid bearing annealing. When heating, the bearing should be placed on the mesh frame, not in contact with the bottom of the box or the wall of the tank. The oil surface will submerge the bearing, and the oil should be able to convect and heat the bearing evenly. In the case of conditions, it is best to heat the bearing on the bearing heater at a temperature of 100 ° C for 3 min.
When hot sets, heat the bearing all the way to the shoulder. If the sleeve does not enter, use a sleeve to hold the inner ring and gently tap it with a hammer. After the bearing is set, the transformer oil in the bearing is blown off with compressed air.
3) Grease for motor rolling bearing
Motor rolling bearing grease generally uses No. 3 lithium base grease or composite No. 3 lithium base grease, and can also be used with composite calcium base and calcium sodium base grease. The filling amount of grease should be 1/2~1/3 of the space of the bearing chamber, and the motor with high speed can be slightly reduced.
The judgment and disassembly of the motor rolling bearing fault requires certain experience and skill. This requires technicians and operators engaged in motor repair work to accumulate through practical work and summarize the long-term field work.
