Outer Ring Modifications

Standard Snap Ring Groove N Snap Ring Inserted NR

Most applications require the outside surface of the bearing’s outer ring to be straight (without channels or lips, etc.). This is to be considered "normal" and needs no designation as a specifier. Some application designs call for the bearing to be held in place by using a snap ring, a narrow, thin steel external ring applied (or snapped) to the bearing for positioning purposes. This requires a groove to be machined into the outer ring of the bearing that will accept the snap ring. This modification is referred to as the snap ring groove and is designated with the suffix N by NTN. If the bearing is supplied with a snap ring installed in the bearing’s snap ring groove, the NTN suffix designation is NR.

Other application designs specify the bearing to be supplied with a flange or flanged outer ring. (The ring is formed with a flat extension to the outside edge of the outer ring which is used for positioning purposes.) NTN’s designation for this design is the prefix FL.

The primary purpose of both the snap ring and flanged outer ring is to position and hold the bearing’s outer ring in its proper position in the housing.