NEEDLE ROLLER BEARING AND CRANKSHAFT SUPPORT STRUCTURE

摘要

A needle roller bearing (11) has an outer ring (12) including a first outer ring member (13) that has a center angle greater than 180 degrees and also including a second outer ring member (14) that has a center angle less than 180 degrees; needle rollers (15); and a retainer (16) including a pair of ring sections and also including column sections (17c) and column sections (18c) placed between the pair of ring sections. The needle roller bearing satisfies d < X < D and the expression (1) below, with D the inner diameter of the outer ring (12), r the radius of a needle roller (15), d the outer diameter of the retainer (16), X the length of a line segment l1 connecting circumferential ends of the inner diameter surface of the first outer ring member (13), and ? the angle which, when the column sections (17c) are placed on a straight line l2 passing through the center of the outer ring (12) and parallel to the line segment l1, is formed by the line l2 and a line l3 connecting the center of a needle roller (15) located adjacent to each column section (17c) and the center of the outer ring (12). (1)