Regulating Axial Clearance of Bearing
The axial clearance of a bearing is the distance between the inner ring and the outer ring along the axial direction. In the process of bearing installation, when the bearing encounters load, the bearing must be adjusted at the outer end of the inner ring, and the strict adjustment of the axial clearance can ensure the normal functioning and operation of the bearing.
1. Determining the Clearance Gap of Bearings
The installation of a bearing should start with determining the desired axial clearance of the bearing. Regardless of type of bearing, the basic requirements for its axial clearance should be based on the load size, the maximum speed and the working temperature of the bearing. The axial clearance of a light radial load bearing is generally selected within 0.010~0.030mm, a heavy radial load bearing within 0.030~0.080mm. Under the condition of a heavy axial load, this clearance range will be larger, generally selected at 0.050~0.120mm, and the bearing of a large axial load should generally be selected within 0.080~0.210mm.
2. Methods for adjusting the clearance gap of bearings
(1) Adjustment of bearing clearance by pressing the outer end of inner ring
The axial clearance of a bearing is adjusted by a fitting device. The pressing force is usually generated by bolts. There are two kinds of pressure loading ,one is a eccentric pin and another is a cylindrical sleeve. For example, when the eccentric pin is used for pressing, the two eccentric pins are spaced at 180°, and the clearing adjusting bolt is placed at the outer end of the bearing’s inner ring. Rest the two pins on the two pins, tighten the bolts to make the dersired distance between the pins, thus making the required axial clearance.
(2) Adjustment of bearing clearance by direct pressing of bearing inner ring
This method is suitable for adjusting the clearance of bearing, which is directly pressed on the surface of tail end inner ring. The rotary speed is usually within 150-200rpm. The adjustment should be gradually started from the side, rather than a one-time adjustment, and it is stopped when the required axial clearance is reached.
(3) Adjustment of bearing clearance with heat shrinkage
Heat shrinkage is suitable when the axial clearance of the bearing is too large. If a cylindrical sleeve is used, an appropriate amount of heating shrinkable material is bonded on the inner wall of the outer end of the inner ring, and the relative position of the inner and outer rings can be pushed each other as the temperature of the heat shrinkable material is increased. To prevent the heat shrinkable material from moving in the axial direction, a press block is used to squeeze the heat shrinkable material with a bearing after it achieves enlargement.
3. Major Issues in Adjustment of Clearance Gap
(1) The axial clearance should not be too small: If the axial clearance is too small, it will increase the fatigue of the bearing and make the bearing not work in normal.
(2) The bearing should be shallowly loaded: The too large stress of loading may cause the inner ring to deform and make the bearing not work in normal.
(3) When the bearing is assembled and disassembled，The pressing ring should not be excessively forced and the pressing distance should not be too large or too small.
In conclusion, the adjustment of the axial clearance of the bearing is necessary and critical to its proper operation. So when it is installed， it is necessary to be adjusted in accordance with the regulations and noted of the corresponding points.
