Patent ID: 8393800

Claim:
A needle roller bearing comprising: a cylindrical outer ring formed by circumferentially connecting a first outer ring member having a center angle larger than 180° and a second outer ring member having a center angle smaller than 180°; a plurality of needle rollers arranged along an inner diameter surface of said outer ring; and a retainer including a pair of ring sections and a plurality of column sections arranged between said pair of ring sections, and having pockets for housing the plurality of needle rollers, between adjacent column sections, wherein d≦x≦D and a formula (1) below are satisfied in which reference D represents an inner diameter dimension of said outer ring, reference r represents a radius of said needle roller, reference d represents an outer diameter dimension of said retainer, and reference X represents a length of a line segment l 1 connecting circumferential ends of an inner diameter surface of said first outer ring member, and when a line l 2 passing through the center of said outer ring and parallel to the line segment l 1 passes through the center of one of said plurality of column sections, reference θ represents an angle formed between the line l 2 and a line l 3 connecting the center of said needle roller adjacent to the above column section to the center of said outer ring, [ Formula ⁢ ⁢ 1 ] ⁢ 2 ⁢ { ( D 2 - r ) ⁢ cos ⁢ ⁢ θ + r } < X . ( 1 )