Abstract: On an inner peripheral surface of a bearing hole into which a shaft is inserted, concave oil supply surfaces arranged dispersively like separated islands and a sliding surface continuous around the oil supply surfaces to hold an outer peripheral surface of the shaft are formed: a maximum height difference between the sliding surface and the oil supply surfaces is not less than 0.01% and not more than 0.5% of an inner diameter Di of the sliding surface; a surface aperture area ratio of pores at the sliding surface is not more than 10%; a surface aperture area ratio of pores at the oil supply surfaces is more than 10% and less than 40%; and an area of each of the oil supply surfaces is not less than 0.03 mm2 and not more than 0.2×Di2 (mm2).

Abstract: An oil-impregnated sintered bearing comprises a bearing hole. In the bearing, sliding surfaces supporting an outer circumferential surface of a shaft and an oil supply surface whose diameter is larger than that of the sliding surfaces are formed on an inner circumferential surface of the bearing hole into which the shaft is inserted. The sliding surfaces and the oil supply surfaces are adjacent to each other in the axial direction of the bearing hole. A height gap “d1” between the sliding surfaces and the oil supply surface is not less than 0.01% and not more than 15% of an inner diameter of the sliding surfaces. A surface opening percentage of the sliding surfaces is not higher than 10%. A surface opening percentage of the oil supply surface is higher than 10%. An average circle-equivalent diameter of opening parts of pores on the sliding surfaces is not larger than 20 ?m.

Abstract: On an inner peripheral surface of a bearing hole into which a shaft is inserted, concave oil supply surfaces arranged dispersively like separated islands and a sliding surface continuous around the oil supply surfaces to hold an outer peripheral surface of the shaft are formed: a maximum height difference between the sliding surface and the oil supply surfaces is not less than 0.01% and not more than 0.5% of an inner diameter Di of the sliding surface; a surface aperture area ratio of pores at the sliding surface is not more than 10%; a surface aperture area ratio of pores at the oil supply surfaces is more than 10% and less than 40%; and an area of each of the oil supply surfaces is not less than 0.03 mm2 and not more than 0.2×Di2 (mm2).

Abstract: An oil-retaining sintered bearing in which friction coefficient can be reduced and a sliding property as a bearing can be improved by supplying a sufficient amount of oil to a sliding surface and preventing the supplied oil from moving to an interior from the sliding surface; a sliding surface 3 supporting an outer peripheral surface of a shaft and a helical oiling surface 4 around a shaft axis of a bearing hole are adjacently formed on an inner peripheral surface of the bearing hole into which the shaft is inserted; a surface open rate at the sliding surface 3 is not larger than 10%; and a surface open rate at the oiling surface exceeds 10%.

Abstract: In order to supply sufficient amount of oil to one or more sliding surfaces and to prevent the supplied oil from moving from the sliding surface(s) to an inside so as to achieve lower friction and improve sliding performance of a bearing, in an oil-impregnated sintered bearing 1, sliding surfaces 3 supporting an outer circumferential surface of a shaft 11 and an oil supply surface 4 in which a diameter is larger than that of the sliding surfaces 3 are formed on an inner circumferential surface of a bearing hole 2 into which the shaft 11 is inserted, to be adjacent in an axial direction of the bearing hole 2, a height gap “d1” between the sliding surfaces 3 and the oil supply surface 4 is not less than 0.

Abstract: An oil-retaining sintered bearing in which friction coefficient can be reduced and a sliding property as a bearing can be improved by supplying a sufficient amount of oil to a sliding surface and preventing the supplied oil from moving to an interior from the sliding surface; a sliding surface 3 supporting an outer peripheral surface of a shaft and a helical oiling surface 4 around a shaft axis of a bearing hole are adjacently formed on an inner peripheral surface of the bearing hole into which the shaft is inserted; a surface open rate at the sliding surface 3 is not larger than 10%; and a surface open rate at the oiling surface exceeds 10%.