Does using grease or oil to lubricate ball bearings help protect them from contaminants?

The use of lubricating grease or oil in ball bearings can indeed help them resist the invasion of pollutants to a certain extent. These two lubricants form a protective film inside the bearing, which not only reduces direct contact and friction wear between metals, but also plays a sealing role, effectively blocking external dust, moisture, and other pollutants from entering the bearing interior. Due to its viscous nature, lubricating grease can form a relatively solid lubricating film on the surface of bearings, which has a relatively strong resistance to pollutants; Lubricating oil forms a thin oil film inside the bearing through its fluidity. Although its ability to resist direct invasion of pollutants is slightly weaker, it can effectively prevent pollutants from entering with appropriate sealing devices. Therefore, selecting appropriate lubricants and maintaining good sealing of bearings are key to protecting them from contamination.