⑴Improve the guidance accuracy of bearings.

⑵Improve rigidity.

⑶ Reduce vibration and noise during operation.

⑷Prevent the sliding of the rolling elements relative to the inner and outer ring raceways caused by the inertial moment.

⑸Compensate for wear and pressure sinking during operation and extend working life.

⑹ Keep the rolling elements and bearing rings in the correct position.