Hitachi Chemical Company, Ltd.

Hitachi Powdered Metals Co., Ltd.

Naoki Nishizawa

Hidekazu Tokushima

Hideaki Kawata

Takeshi Yanase

The oil-impregnated sintered bearing made of iron-copper sintered alloy consisting of 10-59% of Cu, 0.5-3% of Sn, and balance of Fe and impurities, includes pores in the iron-copper sintered alloy matrix of not less than 800 per mm, has pores exposed at 20-50% by area ratio at the inner circumferential surface with diameters greater than 100 &#x3bc;m, not more than 0.5%, respectable to the total pores number. The pores number with diameters greater than 80 &#x3bc;m and not greater than 100 &#x3bc;m, not more than 0.1%, respectable to the total pores number with diameters greater than 60 &#x3bc;m and not greater than 80 &#x3bc;m is 0.5-1.5%, respectable to the total pores number, with diameters greater than 40 &#x3bc;m and not greater than 60 &#x3bc;m is 0.8-3% respectable to the total pores number, and the remainder pores are with diameters less than 40 &#x3bc;m.

Oil-impregnated sintered bearing and production method therefor

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 &#x3bc;m at 0.9 to 2.5%, interparticle pores with circle-equivalent diameters of 63 to 75 &#x3bc;m at 0.1 to 1.2%, and large interparticle pores with circle-equivalent diameters of larger than 75 &#x3bc;m at not more than 3%, with respect to the total number of the pores.

Growing community of inventors

Kashiwa, Japan

Naoki Nishizawa