Needle roller bearing

摘要

The needle roller bearing B in this embodiment comprises a cage 1 having a plurality of elongated window-shaped pockets 1a formed therein at predetermined circumferential intervals, and a plurality of needle rollers 2 rollably received and held in the pockets 1a. The four corners A of each pocket 1a of the cage 1 are provided with relief portions 1an4 each having a circumferentially recessed arcuate peripheral wall surface. The circumferential dimension between the circumferential top 1a41 of the relief potion 1a4 and the pocket wall surface 1a1 is set with respect to the diameter Dw of the needle rollers 2 such that 0.01