The effect of elasticity in powder metal gears on tooth loading and mean coefficient of friction

Abstract

Powder metal gears have a lower density than conventional steel gears due to their intrinsic porosity from the manufacturing process. This also results in a lower elasticity leading to larger deformations and lower contact pressure in a gear contact. By using different modelling tools (namely FEA and available commercial software), the load behavior along the line of action is studied to compare the influence of lower elasticity with standard wrought steel elasticity for FZG-C type gears. A further step is taken analyzing this effect on the mean coefficient of friction through the recalculation of the gear mesh power loss factor. Conclusions observed are differences in load distribution and marginal differences in the gear mesh power loss factor when comparing sintered and wrought steel FZG-C type gears. Sintered steel showed a marginally longer line of action and simultaneously a decrease of the single tooth contact length when compared to wrought steel, while differences in the gear mesh power loss factor proved non-essential due to the spread in previously measured experimental data.