Which bearing feature is aimed at preventing contamination from entering the bearing?

The feature that effectively prevents contamination from entering the bearing is shields. Shields act as barriers that block dust, dirt, and other foreign particles from entering the internal components of the bearing. They create a protective environment around the bearing while allowing for some movement and lubrication flow, if designed appropriately.

Seals also provide a similar function, but their primary purpose is more about retaining lubrication within the bearing rather than solely blocking contamination. Lubrication is critical for reducing friction and wear but does not directly prevent contaminants from entering. Clearances refer to the spaces or gaps between components and influence the fit and operation of the bearing rather than serving as a protective measure against contamination.

Thus, shields are specifically designed to safeguard the bearing from external contaminants while still allowing for the necessary operation of the bearing mechanism.