Patent ID: 8132965

Claim:
A hydrodynamic type grease-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 slating against an axial direction provided in the bearing surface; and a lubricant impregnated in pores inside said bearing body, wherein the lubricant impregnated into said bearing body is a lubricating grease comprising a thickener in a compounding ratio of from 0.1% to 5.0% by weight, wherein the rate of area of surface holes of the bearing surface is set within a range of 3%-15%, wherein 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 the inside of the bearing body and the bearing clearance through the surface holes of the bearing surface, so that the lubricating film continuously non-contact supports the rotating shaft, wherein the thickener of said lubricating grease is more than one type of urea compound selected from the group represented by the following formula (1): R1-NHCONH—R2-NHCONII—R3, (1) wherein R2 represents an aromatic hydrocarbon group having from 6 to 15 carbon atoms, R1 and R3 represent an aromatic hydrocarbon group having from 6 to 12 carbon atoms or an alkyl group having from 8 to 20 carbon atoms, and the rates of the aromatic hydrocarbon group in R1 and 123 range from 0% to 100% by mole.