Bending Fatigue Performanceof Symmetric and Asymmetric Composite Gear

Abstract

Gear is the principle power transmission element finding diverse industrial applications. Polymer gears have found major application in industries where load involved is less and the load transmission is in one direction only. In this work symmetric gear (20/20) asymmetric gears (20/34, 34/20) were chosen to understand the kinematic and load carrying performance. Unfilled and 20 % glass filled polypropylene materials were considered for molding symmetric and asymmetric gears

In this Paper, work kinematic performance was evaluated by commercial FEA package ANSYS. Gear tooth geometry was modelled. Symmetric and asymmetric gears were injection molded for bending fatigue performance evaluation. Since polymer gears are more prone to bending fatigue failure rather than that of contact fatigue, effort has been put to develop appropriate test facility. The bending fatigue performance of asymmetric gears, a fixture has been designed and fabricated in workshop. Addition of reinforcement found to improve load carrying capacity. Molded gears were subjected to sinusoidal variation of displacement and load required at every stage of cycles was measured and monitored. For both the considered materials, chosen loading frequency and chosen displacement magnitudes, the amount of load required for gear tooth deflection found to decreases. When the loading frequency increases molded gears exhibit improved load carrying performance. Drive side pressure angle and critical gear tooth section found to influence the bending load carrying performance of symmetric and asymmetric gears.