Vertical Motors: Why Angular Contact Ball Bearings Are Used At The Locating End

Vertical motors adopt angular contact ball bearings at the locating end mainly to realize axial positioning, support the self-weight of the rotor, and guarantee structural rigidity and running accuracy.

As the rotor is installed vertically, its self-weight produces a sustained downward axial force, together with extra axial loads from working loads and fluid impact. Ordinary deep groove ball bearings can only bear a small amount of axial force and are prone to axial play, failing to keep the rotor stably positioned. In comparison, angular contact ball bearings can withstand large unidirectional or bidirectional axial loads, which effectively restrain the rotor from axial movement and maintain its operating position.

These bearings feature high support rigidity. While bearing axial loads, they also undertake radial loads. With reasonable mounting methods, they can resist overturning moments and prevent rotor swing. Especially for pumps, fans and other equipment subject to axial impact, they ensure smooth operation and reduce vibration and noise.

The locating end of vertical motors requires precise control over rotor axial clearance. Angular contact ball bearings allow accurate preload adjustment. This avoids axial play caused by excessive clearance as well as bearing overheating and seizure resulting from over-tightening, enabling long-term stable operation.

At the locating end of vertical motors, a single angular contact ball bearing or paired bearings are generally used to carry the rotor weight and external axial loads, with the mounting direction designed to primarily bear downward axial force. A single bearing is usually mounted in the standard form: the outer ring fits closely with the end cover, and the inner ring forms an interference fit with the shaft journal. Oriented to bear the downward axial force generated by the rotor, the bearing also provides reliable radial support.

For working conditions with large axial loads or high rigidity requirements, two angular contact ball bearings are installed back-to-back with their large ends facing outward. This structure can bear bidirectional axial forces and greatly enhance the capacity to resist overturning moments. During installation, a proper preload shall be applied by means of lock nuts, spacer sleeves or compression of the end cover, so as to eliminate internal clearance without causing overheating due to excessive preload.