Angular contact ball bearings are mainly used in machine tool spindle. In most cases, there is a lock on the outer ring which resulting in a ring groove. So the angular contact ball bearings applied to the machine spindle can not be filled smooth grease as other bearings on the other machine. If installing a set of smooth adjuvant system, it will not only increase the cost but also complicate machine's structure.
Barden Division of FAG has dealt with this problem. The advanced method is to embed a new fluted ring to the bearing. The groove’s depth should be shallow than that of normal bearing, and just fit for the gap from the outer ring flange. The application of this seal ring are helpful to avoid the leakage of smooth greace from both sides, as well as preventing the dirt intrusion.