Finite Element Analysis of Stress Relief in Teeth of Spur Gear by Varying Key Shaft’s Size and Location

This paper investigated the Finite Element Analysis (FEA) via ANSYS software of bending stresses in involute gears with different keys shape.It has described the use of ANSYS for predicting the effect of keys on stress distribution in spur gear.The numbers and location of keys used as parameters to observed its effect on the relief stress by changing of key sizes in spur gear.Two modules are used (m=2 and m=7) to tests the spur gear each with one, two, three and four keys position inclusive parallel key (rectangular cross section), parallel key (square cross section) and the other type is parallel key (circular cross section).This analysis of stress was carried out by observing the key factors that determine its relief, the introduction of sizing, location and number of the stress-relieving features at a certain place reaching to relieve maximum in stress performance, otherwise the strength decreases.Using single circular key as a stress reliving feature gives more stress reduction for m=2 and double circular key within m=7.The results for pitch circle diameter=50 mm, outside diameter=54 mm, root diameter=45 mm, center diameter=47 mm, fillet=0.4mm, thickness=3.14mm, and for Case-1-, when B=8 mm and h=7 mm, the maximum equivalent stress is 9635 MPa.In addition, when B=8 mm and h=8 mm, the maximum equivalent stress is 10081 MPa.Also, when the diameter of key=8 mm, the maximum equivalent stress is 9303 MPa.This paper revealed that minimum stresses, therefore, optimum key shaft for spur gears are single circular key for module 2 and double circular key for module 7, and that key geometry, size and number also determine the efficiency of the gears.