Sintered bearing for motor-type fuel pump with excellent corrosion resistance, wear resistance and conformability

摘要

Provided is a novel bearing for motor-type fuel pump that comprises a Zn-P-Ni-Sn-C-Cu-based sintered alloy. The bearing has a corrosion resistance to a coarse gasoline containing sulfur or an organic acid(s); a superior wear resistance; and a superior conformability with a shaft as a counterpart. Thus, the bearing is suitable even for use in a downsized fuel pump. The bearing has a structure in which a base comprises 3 to 13% by mass of Zn, 0.1 to 0.9% by mass of P, 10 to 21% by mass of Ni, 3 to 12% by mass of Sn, 1 to 8% by mass of C and a remainder composed of Cu and inevitable impurities; the base comprises a solid solution phase of a Zn-Ni-Sn-Cu alloy; a Sn alloy phase containing not smaller than 15% by mass of Sn is formed in grain boundaries of the base; a porosity of 8 to 18% is exhibited; and free graphite is distributed in pores.