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What is motor bearing running and the harm it causes?

Date:2023-10-15   Author:XINDA MOTOR

The running outer ring of the motor means that due to wear between the motor bearing outer ring and the bearing seat, the matching gap between the bearing outer ring and the bearing seat is too large, which is called running outer ring or running outer ring. If the gap between the inner ring of the bearing and the shaft is too large due to excessive wear, it is called inner circle running or inner sleeve running. When the wear gap between the motor bearing and the shaft or bearing seat reaches a certain level, the friction between the motor rotor and the stator is called a motor sweep boring failure. The phenomenon is that the motor does not rotate, makes abnormal sound, generates heat, and the coil is burned out.

1. The harm caused by the running sleeve to the motor

(1) If the motor bearing has a running jacket problem, it will cause uneven air gaps in the motor, increase the no-load current of the motor, and reduce the motor power. Normally, the air gap of small and medium-sized asynchronous motors is between 0.2-1.5mm. If the air gap is uneven, the unilateral magnetic pull of the motor will increase, the stator and rotor of the motor will sweep, causing greater vibration and noise, and damage the rotating shaft. , damage the rolling bearings and seriously affect the use of the motor.

(2) If there is a problem with the inner sleeve of the motor bearing, it will cause the shaft neck to dissipate heat, and the lubricating oil at the bearing will also become liquid and leak due to the temperature rise, which will cause the rolling bearing to burn out due to lack of oil. In severe cases, it will The occurrence of scanning problems, accompanied by severe vibration and noise, will have a serious impact on the use effect and life of the motor.

2. Detailed solutions to the lap problem

(1) After the motor bearing running problem occurs, some places may use surface sealing and punching holes on the surface of the bearing chamber to repair it. However, as a result, the concentricity of the assembly motor bearing will not be high, and the motor's Disassembly and assembly are inconvenient, and will still damage the rolling bearings and cause damage to the motor. It cannot completely solve the rolling bearing running problem. At this stage, the more common and effective methods are potting and welding repair. Grouting is used when running the outer sleeve, and welding repair is used when running the inner sleeve. This method can not only ensure the quality of repair, but also prolong the operation of the motor. time.

(2) Specific operating conditions. When a rolling bearing has a running sleeve, the first thing to do is to disassemble the motor, clean the end cover of the running sleeve, measure the depth of the bearing chamber and calculate the value, and then draw a processing drawing based on the outer diameter of the motor bearing. In order to better ensure that the machined hole is round and meets the requirements, it is necessary to fix the end cover of the motor on the lathe chuck for alignment, and then expand the rolling bearing chamber of the original rolling bearing to 6-10mm.

After that, the sleeve is processed according to the size of the motor bearing outer ring and the rolling bearing inner ring. After completion, the end cover is inserted using the cold assembly method. During the process of inserting the end cap, please note that the processed sleeve must be completely submerged when placed in a metal container and immersed in liquid air, and it must be cooled for ten minutes before inlaying. In the future, it must be cooled and processed at room temperature. Achieve the required size.

When the inner sleeve of the motor bearing occurs, the processing drawing must be drawn first, and then repaired by welding repair method. The journal should be cleaned before welding repair. In order to better ensure the quality of welding repair, symmetrical welding method is usually used, and the welding current is controlled at 100A. After welding is completed, insulation material should be used for insulation to allow the shaft to cool naturally. Finally, it is cut and processed according to the processing drawing drawn in advance.