OIL-IMPREGNATED SINTERED BEARING AND PRODUCTION METHOD THEREFOR

摘要

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 mum at 0.9 to 2.5%, interparticle pores with circle-equivalent diameters of 63 to 75 mum at 0.1 to 1.2%, and large interparticle pores with circle-equivalent diameters of larger than 75 mum at not more than 3%, with respect to the total number of the pores.