ROLLING BEARING WITH ELLIPTIC RACEWAY SURFACE

PROBLEM TO BE SOLVED: To solve such a problem with a conventional non-complete round bearing that, since the non-complete round amount (elliptic amount = major axis diameter - minor axis diameter) of the outer ring of a bearing unit is sufficient for a radial clearance and a preload state is produced in a minor axis diameter portion, the end faces of rolling elements interfere with the side face of a race, and the assembly becomes difficult. SOLUTION: The raceway surface 1b of an inner ring 1 is formed in a complete round shape, and the raceway surface of the outer ring2 is formed in an elliptic shape. The minor axis diameter S1 of the raceway surface 2b of the outer ring 2 of the bearing unit is increased larger than the circumscribing circular diameter Ew of the rolling elements 3 (S1 > Ew). Or the raceway surface 1b of the inner ring 1 is formed in an elliptic shape, and the raceway surface 2b of the outer ring 2 is formed in a complete round shape. The major axis diameter S2 of the raceway surface 2b of the inner ring 2 of the bearing unit is set smaller than the inscribing circular diameter Iw of the rolling elements (S2