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Test run inspection items after high temperature bearing installation

Update:29-11-2019
Summary:

After the high-temperature bearing installation is comp […]

After the high-temperature bearing installation is completed, a test run check is performed to check whether the installation is correct. Small machines can be rotated by hand to confirm that they rotate smoothly. Inspection items include poor operation due to foreign objects, scars, and indentations, unstable torque due to poor installation and poor processing of the mounting seat, excessive torque due to too little clearance, installation error, and sealing friction, etc. Wait. If there is no abnormality, power operation can be started.

Power operation starts from no-load low speed, and gradually increases to rated operation under predetermined conditions. The test operation check items include whether there are abnormal sounds, changes in bearing temperature, lubricant leakage or discoloration, etc. If abnormality is found, the operation should be stopped immediately, the machine should be inspected, and if necessary, the high temperature bearing should be removed for inspection.

1. Prevention of assembly foreign matter: When the bearing is mounted on the rotor for dynamic balancing, it is easy to enter the iron shavings generated during dynamic balancing into the bearing, so it is better to perform dynamic balancing before installing the bearing. For ease of assembly, some manufacturers apply some oil or grease to the bearing chamber during assembly for lubrication, but it is often difficult for the operator to control the amount. If oil or grease accumulates more in the bearing chamber, it is very difficult when the bearing is rotating. Easy access to high-temperature bearings along the shaft. Bearing room Fortunately, do not apply oil or grease. If it is impossible to coat, control it so that there is no accumulation in the bearing room.

2. Prevention of paint rust: The feature of paint rust is that it is frequently used in sealed motors. The motor sounds good when it is assembled, but after some time in the warehouse, the abnormal noise of the motor becomes very large. Severe rust. In the past, many manufacturers would think that it was a bearing problem. After our continuous publicity, now the motor factory has realized that it is mainly a problem of insulating paint. The problem is mainly because the acidic substances volatile from the insulating varnish form corrosive substances at a certain temperature and humidity, which will cause high-temperature bearing damage after the bearing channel is corroded. This problem can only be solved by selecting a good insulation paint and ventilating it for a period of time after drying.

3. Selection and control of shaft and bearing chamber tolerances: After the bearing is pressed into the bearing, it should rotate flexibly without blocking. If there is obvious inflexibility in rotation, the size of the shaft is too large, and the tolerance must be adjusted downward. If the bearing presses into the shaft and rotates by hand with a clear "rustle" feeling, it may be that the tolerance of the shaft is too large or the roundness of the shaft is not good. Therefore, it is necessary to control the roundness when controlling the tolerance of the shaft and the bearing room. At present, many domestic manufacturers only control the tolerance and do not control the roundness.

4. Bearing assembly method: Because the bearing is a high-precision product, improper assembly can easily cause damage to the bearing channel, resulting in high-temperature bearing damage. The bearing should have a special mold when it is assembled, and it cannot be beaten at will. When the shaft is pressed, it can only be stressed by a small circle, and when it is pressed by a large circle, it can only be stressed by a large circle. It is required to use air pressure or hydraulic pressure during assembly, and it must be touched out of the horizontal state when press-fitting. If it is inclined, it will cause the bearing channel to be damaged due to stress, which will cause the bearing to conduct sound.

The life of high-temperature bearings is closely related to manufacturing, assembly and use. It must be done in every link to make high-temperature bearings in a good running state, thereby extending the service life of the bearings.

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