THRUST ROLLER BEARING

PROBLEM TO BE SOLVED: To provide a thrust roller bearing, in which wear of a roller is reduced and torque is reduced. SOLUTION: The thrust roller bearing includes: a plurality of rollers; and a retainer 20 in which retaining holes 22 retaining these rollers are circumferentially formed at equal intervals. A radially flat annular plate 24 is formed to the retainer 20, on an inner diameter side of the retaining holes 22. In the annular plate 24 of the retainer 20, lightened parts 30 circumferentially extended in a circular-arc manner at a center angle of 45 degrees are formed at four portions which are rotation symmetry on the same circumference. Wedge-like parts 32 getting thinner from circumferential ends toward the circumferential center are formed at both circumferential ends of the lightened parts 30, and through-holes 34 axially penetrating the lightened parts are formed at the circumferential centers of the lightened parts 30. Dynamic pressure is generated in the lightened parts 30 of the retainer 20 by rotation of the retainer 20. COPYRIGHT: (C)2011,JPO&INPIT