Heat generation in Fe-C-Cu-MoS<inf>2</inf>-sintered spur gears under unlubricated conditions

In many applications, gears operate under unlubricated conditions and there is a need for new materials with a good friction and wear characteristics for use in these situations. A new alloy, Fe-C-Cu + MoS2, was developed using a powder metallurgy processing route for gear and bearing running under unlubricated operating conditions. Spur gears were compacted from the pre-alloyed powders and sintered. The gear performance was evaluated using a power absorption type gear test rig. The temperature rise measured during testing depends on the material composition, porosity, and coefficient of friction. A thin lubricant film formed in the MoS2-added gears affects the friction and thereby the heat generation during running. An optimum amount of MoS2 addition, 3 per cent, is found beneficial in reducing the surface temperature rise. The analytical model predicts the temperature rise with a reasonable accuracy. © IMechE 2007.