Design of Spur Gears Using Profile Modification

In this work, a profile modification technique was used in design of a spur gear. In this technique, the tooth-sum is varied to obtain the desired contact ratio and low contact stress for a specified center distance. A program has been developed using C language to compute the contact stresses by varying the amount of profile shift for a tooth-sum of 100 teeth (±4%). The selected tooth-sum of 96, 100, and 104 gears was subjected to cyclic loading using a back-to-back test rig. The morphology of the damaged gear tooth surface after cyclic loading was examined by scanning electron microscopy. The morphological investigation reveals that the degree of damage observed in negative number of teeth alterations is less compared to standard and positive alteration tooth-sum due to lower contact stress.