BOSTON gear bearing is a type of rolling-element bearing similar to an epicyclic gear. Gear bearings consist of a number of smaller 'satellite' gears which revolve around the center of the bearing along BOSTON GEAR Bearing a track on the outsides of the internal and satellite gears, and on the inside of the external gear. Each gear is in between two concentric rings. Therefore, the widths of the satellite gears must all be the same.

In order for the surfaces to provide efficient axial meshing, the teeth must either be beveled or made with engagement. This avoids misalignment, sticking, and reduces sliding friction in the bearing. For instance, the illustrations present implementations of bearing gears with beveled teeth NSK 6202du Bearing and rollers on their adjacent end faces as well as a herringbone engagement to provide minimal axial shift due to opposite sloping teeth.