Some Obsevations on the "Wear" of Spur Gears

概要

論文の詳細を見る
Spur gears of 6 : 4 brass or of α-brass were engaged and driven with the speed of 15 rpm at room temperature. After driving, slip bands and dislocation etch pits near the tooth surface were observed through an optical microscope. Extruded or intruded broad slip bands and voids which appeared during driving along the slip band were sometimes observed; these are features of a fatigue failure. It was also observed that, at broad slip bands or microscopic cracks, small fragments fall off during driving. The arrangement of dislocation etch pits was quite different from that observed when α-brass plates were mutually worn away. (It is known that 6 : 4 brass consists of α and β' phases, therefore it may be possible to think that the part of α-phase in 6 : 4 brass acts in the same way as α-brass.) The tooth surface after driving looked flat and smooth with a naked eye; this state is customarily called a "wear" in the case of a gear. These phenomena and another results described in the text suggest that customarily called "wear" in a gear is a fatigue failure near the tooth surface.