Kabushiki Kaisha Sankyo Seiki Seisakusho

Nidec Sankyo Corporation

Sankyo Seiki Mfg. Co., Ltd

Toru Nakanishi

Hisaya Nakagawa

Michiaki Takizawa

Takehiko Yazawa

Takeshi Kaneko

A bearing unit comprises a cylindrical oil-impregnated bearing, in which a bearing bore to support a turning shaft is formed so as to enable the turning shaft to turn; a bearing holder, in which the oil-impregnated bearing is fixed by an inner bore; a first groove being formed in an axial direction on an inner circumferential surface of the oil-impregnated bearing; and a second groove being formed in an axial direction on at least one of an outer circumferential surface of the oil-impregnated bearing and an inner circumferential surface of the bearing holder. The second groove is formed so as to have a greater depth than that of the first groove. The second groove is also formed so as to have a larger cross section than that of the first groove.

Bearing unit

A sintered oil-impregnated bearing 20 used in a bearing device 30 is made by molding a mixture of a composite fine particles (main material) and a solid lubricant previously added to the main material in a proportion of about one weight percent to about three weight percent, wherein the main material comprises composite fine particles composed of iron powders having surfaces coated with copper, and the solid lubricant comprises fine particles made of an inorganic compound such as molybdenum disulfide and having surfaces coated with copper, sintering the mold at a temperature in a range of 650.degree. C. to 700.degree. C. to form a sintered body 20b, and impregnating the sintered body 20b with lubricant oil. Since the sintered body 20b itself has lubricity, the sintered oil-impregnated bearing is free from abrasion or seizure even if oil is used up.

Sintered oil-impregnated bearing, manufacturing method thereof, and

An object of this invention is to provide a bearing device for an electric motor in which a bearing holder holding an oil-impregnated bearing provides good area contact from the beginning and can be readily formed with high productivity. In the bearing device for an electric motor in which a bearing-supporting cylindrical recess is formed in one end face of a bearing holder in the form of a hollow cylinder, and an oil-impregnated bearing having a shaft-inserting hole is fixedly fitted in the bearing-supporting cylindrical recess in such a manner that the shaft-inserting hole of the oil-impregnated bearing is inclined with respect to the central axis P of the bearing holder; the bearing-supporting cylindrical recess of the bearing holder is defined by a cylindrical surface whose diameter is slightly smaller than the outside diameter of the oil-impregnated bearing and which is in parallel with the central axis P of the bearing holder, and an abutting annular surface inclined with respect to the central axis P, and the oil-impregnated bearing is arranged inclined in the bearing-supporting cylindrical recess being abutted against the abutting annular surface.

Bearing device for an electric motor

A sintered oil-impregnated bearing is disclosed having a plurality of evenly extending smoothed areas on the inner periphery surface for receiving a rotary shaft, the smoothed areas having a constant angular width of 10.degree. to 90.degree., the remaining surface areas between any adjoining two of said smoothed areas being kept porous. Such a sintered oil-impregnated bearing can be realized without the process of aging and ensures a good oil circulation on the smoothed surface areas, a high precision assembling operation because of the exactly circular and concentric configuration of the inner and outer peripheries and an easy and accurate alignment of the smoothed surface areas and the corresponding contact areas of the rotary shaft. Therefore, a sintered oil-impregnated bearing according to the invention is free from any metallurgical damage and can be manufactured in an existing manufacturing facility without significantly modifying the manufacturing equipment.

Growing community of inventors

Nagano, Japan

Toru Nakanishi