As a key component supporting the operation of the motor, the motor bearing plays an important role in ensuring the stable operation of the motor.For different motor structures and different applications, various factors need to be considered in terms of design, selection, use and maintenance, repair and replacement. All aspects must be done well in order to make the bearing in the best operating state, thereby extending the service life of the motor bearing.

When selecting the motor, the force of the shaft should be considered, and the vertical and axial load sizes should be compared with the sample data to determine whether enhanced bearings need to be selected.According to the load conditions and operating environment conditions, it is determined whether it is necessary to choose a refuel device.

Precautions for bearing use and maintenance：

1. The selection of the motor and the size of the load must be appropriate.The selection of the motor is too small, which is also an important factor in the heating of the bearing.

2. The amount of lubricating oil for bearings is very particular. Grease has good adhesion, wear resistance, temperature resistance, rust resistance and lubricity. It can improve high temperature oxidation resistance, delay aging, dissolve carbon deposits, prevent metal wear chips and oil stains from agglomeration, and improve mechanical wear resistance, pressure resistance and corrosion resistance.The grease in the bearing should not be too much.Too much grease is not only wasteful, but also harmful.The higher the speed of the bearing, the greater the harm.The more grease is filled, the greater the friction torque.Ball bearings are most suitable at 20% to 30%.Excessive lubricating oil leads to poor heat dissipation of the bearing, while too little lubricating oil will cause insufficient lubrication of the bearing and increase friction and temperature.

3. For motors with a power of less than 22KW, there is basically no refueling nozzle, and it is usually impossible to refuel. Such motor bearings are generally maintained once a year.During maintenance, first open the end cap of the non-axial extension end, and wash the bearing with a brush dipped in gasoline. Whether the rotating bearing is flexible and smooth, shake the bearing left and right, and determine whether the gap between the inner ring and the outer ring increases; if the bearing is not rotating flexibly or the outer ring is shaking a lot, replace it with a new bearing.Then open the end cap of the shaft extension end and remove the bottom corner bolts. At this time, the coupling can not be disassembled, and the stator can be pulled out for a certain distance (there is room to clean the bearing). After washing the bearing with gasoline, check the bearing in the same way. If there is no problem with the bearing, add the corresponding oil to both sides of the bearing (non-sealed bearing), and rotate the bearing while refueling. Be careful not to add too much. There is no oil outlet. Too much refueling may lock the bearing.Finally assemble, correct, and fix the motor.Clean up and clean up the scene.

4. For bearings of low-voltage motors greater than or equal to 22KW, we generally have more fuel nozzles. In addition, we accumulated the running time of the motor of this power in the DCS, and then refueled it regularly and quantitatively according to the oil and refueling time required in the manual.Generally, it is refueled when the motor is running, so that the oil can easily enter the bearing (pay attention to safety). After refueling, the temperature of the bearing will rise. If there is no problem with the bearing, after a few hours of operation, the bearing temperature will fall back to normal. State.The method of checking the bearing is the same as above.Clean up and clean up the scene.

5. For the bearings (non-slip tiles) of high-voltage motors, the usual refueling method is the same as above. While refueling, the dirty oil from the oil discharge port will also be cleaned up to avoid clogging the oil discharge port.The maintenance of bearings is generally once every 2 years. Open the gland of the shaft extension end and the non-shaft extension end bearing, and clean up all the oil in the oil chamber and the old oil on the bearing. The outer bearing surface can be cleaned with diesel oil, and the inward bearing surface can be cleaned with clean rags. Clean up the old oil (steam can also be used to clean the bearing if necessary). After the bearing is cleaned and cleaned, add the correct oil, which accounts for two-thirds of the oil chamber. It is appropriate.Disassemble the coupling and start the high-voltage motor at no load for a few hours. The bearing temperature will increase. When the bearing temperature drops back to normal, the high-voltage motor will be stopped. This step is mainly to allow the new refueling product to fully lubricate the bearing.Factory motor bearing maintenance generally does not adjust the bearing gap, and the adjustment of the bearing gap needs to go to a professional motor repair shop.Install the bearing gland, clean it, and clean up the site.

6. For low-voltage motors and high-voltage motor bearings with a power greater than or equal to 75KW, it is best to have PT100 temperature sensors at the shaft extension and non-shaft extension ends. Digital instruments are installed on-site and the temperature signal is connected to the DCS, so that the on-site inspection can visually see the bearing temperature, and DCS can also record the curve of the bearing's operating temperature, automatically warn and stop, so as to protect the bearing.For the bearings of the motors of these important equipment, experienced masters can usually use listening needles to monitor the sound of the bearings when they are running, and judge which stage the bearings are running at, so that they can know it in their hearts.

7. The selection of bearings is based on the size of the axial force on the bearing. When there is no axial force, deep groove ball bearings and cylindrical roller bearings are optional; when there is axial force, angular contact ball bearings and tapered roller bearings are optional.When choosing a bearing, the limit speed and load coefficient of the bearing should be considered.

8. For the replacement of bearings, it is necessary to remind everyone that special bearing tools must be used when the bearings are disassembled during the replacement process, so as to maximize the protection of the shaft from changing shape. In addition, when installing the bearings, the motor shaft must be polished with 1200 mesh gauze. When installing the bearings, the bearings should be heated to 70-80 degrees Celsius and quickly installed into the motor shaft. After the top is tightened, the lubricating oil should be installed after being placed at room temperature.

9. The service life of bearings is very long. Motor bearings below 30KW only need to be cleaned every year and the lubricating oil can be replaced. Motors above 30KW generally have refueling ports, and they are refueled regularly every six months. The amount of oil is added in accordance with the motor manual, generally 10 times the refueling gun, but during the refueling process, you must slow down twice and wait to see if the temperature of the motor rises. It is not advisable to refuel too much.

10. Listening to the sound, when you hear the sound of ”rustling“ and the sound of normal operation is different, this is an indication of the lack of oil in the bearing. When you hear the sound of ”click", it indicates that the bearing has been damaged and should be replaced immediately.