Sintered oil impregnated bearing and its manufacturing method

Abstract

In a sintered oil impregnated bearing constructed of a bearing main body made of a porous type sintered alloy on which is formed a bearing hole for inserting a rotating shaft therethrough, the pores on the axially lying sliding face of the inner peripheral surface of the bearing hole on which the rotating shaft slides are crushed. The sintered oil impregnated bearing is manufactured, at the time of forming powder compact, by forming a through hole defining the bearing hole, by a rod having a roughening section formed thereon, thereby crushing the pores which are in contact with the roughening section, and afterward by sintering the powder compact. Because the pores on the sliding face are crushed, the lubricating oil on the sliding face does not leak, thereby forming a strong oil film having no oil pressure drop on the sliding face, and thus preventing the local contact between the rotating shaft and the sliding face. It is therefor is possible to lower the coefficient of friction of the bearing.

Dependencies are inferred from the claim text.