METHOD FOR MANUFACTURING OIL-RETAINING BEARING FOR PETROL PUMP MOTOR IN POWDER METALLURGY

摘要

A method for manufacturing an oil-retaining bearing for a petrol pump motor in powder metallurgy comprises: powder mixing: mixing the following raw material powder in weight percentage:70% to 85% of Sn element powder, 5% to 10% of composite graphite powder, and the balance copper powder; low-temperature diffusion: conducting low-temperature diffusion on evenly-mixed powder in a diffusion furnace by means of nitrogen protection; compression molding: arranging the powder subjected to low-temperature diffusion in a mold for compression molding to form pressed blanks; sintering processing: sintering the pressed blanks in the N and H reducing atmosphere to form a sintered alloy body; finishing and surface polishing: pressing and reshaping the sintered alloy body by using a pressing mold; and oil-immersion processing: arranging a pressed member into a vacuum oil immersion machine to perform oil-immersion processing. In the manufacturing method, copper-coated graphite powder is added to serve as a solid lubricant to allow Cu-Sn alloy to be combined more easily in a low temperature; in addition, graphite is evenly mixed and is not prone to segregation.