Patent ID: 8523451

Claim:
A roller bearing comprising: an inner ring raceway surface; an outer ring raceway surface; a plurality of rollers interposed between the inner ring raceway surface and the outer ring raceway surface; and a plurality of spacers, each of the spacers being provided between an adjacent pair of the rollers, and each of the spacers having at both axial ends thereof extended portions each facing end faces of the adjacent pair of the rollers, wherein each of the end faces of the rollers has a recessed portion formed therein and each of the extended portions of the spacers has a protruding portion that protrudes toward a corresponding one of the end faces of the rollers and extends into the recessed portion, wherein two of the protruding portions extend into each of the recessed portions, wherein the protruding portions and the recessed portions are arranged so as not to contact each other once mounted in the roller bearing, and wherein the outer ring raceway surface is a single continuous surface having a constant width and that forms a complete circle.