Sintered oil retaining bearing and fabrication method thereof

摘要

A sintered oil retaining bearing has a bearing bore through which a rotary shaft is inserted formed at a bearing main unit made of a porous sintered alloy. The inner circumferential wall serving as the bearing bore includes a center inner circumferential wall located at the center region of the inner circumferential wall, and one end side inner circumferential wall and other end side inner circumferential wall, located at one end side and the other end side, respectively, of the center inner circumferential wall in the direction of the rotary shaft. The center inner circumferential wall has a blinded portion where the air permeability is not more than 0.3x10-3darcy, and air permeability lower than that of the one end side and other end side inner circumferential wall.