GM-18 CONSOLIDATION OF SURFACE LAYER OF P/M GEARS BY FINISH ROLLING WITH SCREW-SHAPED TOOL(GEAR MANUFACTURING)

Abstract

The purpose of this study is to examine a practical application of a finish rolling process using a screw-shaped tool to consolidate the surface layer of sintered Fe alloy gear teeth and to improve the tooth profile accuracy and the load carrying capacity. In this paper, preliminary rolling experiments of sintered Fe alloy rollers are firstly done. The target consolidation level of the surface layer of rollers can be achieved by setting the amount of rolling stock to more than 200μm. Two rollers fatigue tests prove that the surface fatigue durability is greatly improved by above 80% by finish rolling. In finish rolling experiments of sintered Fe alloy gears by the screw-shaped tool, the void rate in the surface layer of gear teeth can be decreased to the same extent as that of rollers by adjusting the amount of rolling stock normal to the tooth surface to 200um. Gears with a good tooth profile accuracy and a good surface finish are produced using the screw-shaped tool with a concave tooth profile. It is confirmed that the tooth surface and the fillet at the root of gears can be rolled in one pass.