Influence of EP Film Properties on Anti-scoring Performance of Gears

抄録

Using a power circulating gear testing machine, the influence of EP film properties on the anti-scoring performance was examined in air and nitrogen gas environments. An electron probe microanalyser and a transmission electron microscope are mainly used to determine the chemical composition and the structure of EP film on tooth surfaces. The findings are as follows : 1) In the case of sulphur-additive (dibenzyl-disulfide), EP film is much formed, and the chief compounds in EP film are FeS and FeS₂. FeS is observed more often in nitrogen gas environment than in an air one. 2) In the case of phosphorus-additive (dialkyl-phosphate), the compounds of Fe₃P and FePO₄ in EP film show a favorable effect for anti-scoring performance as well as the chemical polishing effects.