Patent ID: 7988361

Claim:
A hydrodynamic type oil-impregnated sintered bearing, comprising: a porous bearing body of sintered metal having a bearing surface opposed to a sliding surface of a rotating shaft to be supported via a bearing clearance, and hydrodynamic pressure generating grooves slanting against an axial direction provided in the bearing surface; and lubricating oil or lubricating grease impregnated in pores inside the bearing body, wherein a rate of area of surface holes on the bearing surface is set within a range of 3%-15%, the surface holes being distributed substantially uniformly over the whole area of the bearing surface including areas of the hydrodynamic pressure generating grooves, wherein said lubricating oil or a base oil of said lubricating grease forms a lubricating film in the bearing clearance due to the hydrodynamic pressure generating grooves while circulating between an inside of the bearing body and the bearing clearance through the surface holes on the bearing surface, so that the lubricating film continuously supports the rotating shaft in a non-contact manner, and wherein said lubricating oil or a base oil of said lubricating grease is a lubricating oil selected from among mixtures of poly-α-olefin or hydrogenated compound thereof and ester, and further includes phosphoric ester defined by the following general formula: