Abstract: An oil-impregnated sintered bearing which does not tend to produce squealing noises is provided. The oil-impregnated sintered bearing can be used as a bearing of an electric motor that may be intermittently used for a short time, such as a bearing of a window regulator motor. The oil-impregnated sintered bearing includes pores that include middle-sized pores with circle-equivalent diameters of 45 to 63 ?m at 0.9 to 2.5%, interparticle pores with circle-equivalent diameters of 63 to 75 ?m at 0.1 to 1.2%, and large interparticle pores with circle-equivalent diameters of larger than 75 ?m at not more than 3%, with respect to the total number of the pores.

Abstract: A hard phase forming alloy powder, for forming a hard phase dispersed in a sintered alloy, consists of, by mass %, 15 to 35% of Mo, 1 to 10% of Si, 10 to 40% of Cr, and the balance of Co and inevitable impurities. A production method, for a wear resistant sintered alloy, includes preparing a matrix forming powder, the hard phase forming alloy powder, and a graphite powder. The production method further includes mixing 15 to 45% of the hard phase forming alloy powder and 0.5 to 1.5% of the graphite powder with the matrix forming powder into a raw powder. The production method further includes compacting the raw powder into a green compact having a predetermined shape and includes sintering the green compact. A wear resistant sintered alloy exhibits a metallic structure in which 15 to 45% of a hard phase is dispersed in a matrix. The hard phase consists of, by mass %, 15 to 35% of Mo, 1 to 10% of Si, 10 to 40% of Cr, and the balance of Co and inevitable impurities.

Abstract: A process for producing a sintered composite sliding part having an outer member made of an Fe-based wear resistant sintered member in which a hard phase is dispersed in a matrix at 15 to 70% by volume and an inner member made of a stainless ingot steel. The matrix is made of an Fe-based alloy including 11 to 35% by mass of Cr, and the hard phase is formed by precipitating and dispersing at least one selected from the group consisting of intermetallic compounds, metallic silicides, metallic carbides, metallic borides, and metallic nitrides in an alloy matrix made of at least one selected from the group consisting of Fe, Ni, Cr, and Co. The outer member is formed with a hole, the inner member is closely fitted into the hole, and the outer member and the inner member are diffusion bonded together.

Abstract: An iron-based sintered sliding member consists of, by mass %, 0.1 to 10% of Cu, 0.2 to 2.0% of C, 0.03 to 0.9% of Mn, 0.52 to 6.54% of S, and the balance of Fe and inevitable impurities. The iron-based sintered sliding member satisfies the following First Formula in which [S %] represents mass % of S and [Mn %] represents mass % of Mn in the overall composition. The iron-based sintered sliding member exhibits a metallic structure in which pores and sulfide particles are dispersed in the matrix that includes a martensite structure at not less than 50% by area ratio in cross section. The sulfide particles are dispersed at 3 to 30 vol. % with respect to the matrix. [S %]=0.6×[Mn %]+0.5 to 6.