Regarding the problem of centrifugal fan causing the temperature of INA bearings to rise

A centrifugal fan is a mechanical device that relies on input mechanical energy to increase air pressure and deliver gas. This is a driving fluid machine. When using a centrifugal fan, high bearing temperature is a common fault. The reason for the high bearing temperature is as follows.

1. Poor lubrication, deterioration of grease or insufficient grease.

2. The assembly quality of the INA bearing is poor, the pre-tightening force is too large, and the working clearance is small.

3. The quality of the INA bearing itself is very poor, for example, the original does not need clearance, or the roller or retaining ring is defective.

4. The large bearing of the fan vibration bears the impact load.

5. The INA bearing is not sufficiently cooled, insufficient ventilation or lack of water.

When selecting centrifugal fan bearings, the unit of use will usually be replaced according to the prototype of the equipment manufacturer. In the above example, no attention is paid to whether the selection is appropriate, which is caused by improper selection of INA bearings. Since the shaft and bearing of the centrifugal fan usually choose H7/js6 or H7/k6, the number of matching bearings and bearing seat holes is generally JS7/h6. This kind of cooperation is not very close, and has a limited impact on bearing clearance. Because the connecting bolts of the bearing box and the upper cover are tightened, there is no need to move the centrifugal fan to have a higher speed and higher torque working temperature.

In order to prevent loosening, the tightening force is usually too large to make the working gap smaller. In addition, the INA bearing is heated to cause high temperature; or because the working clearance of the INA bearing is small, the free end bearing cannot automatically move with the thermal expansion of the shaft, so the axial load of the two bearings is too large, which causes the bearing to be damaged. Therefore, when replacing bearings in production, especially when the INA bearings of centrifugal fans have higher speeds and higher operating temperatures, please pay attention to the selection of INA bearings. First of all, please pay attention to whether the speed limit is appropriate. Second, choose C3 with a larger original gap. Group bearings.