Finite Element Analyses of Non-Standard Spur Gears

Abstract

Gears are the mechanical components and are predominate as the most effective means of power transmission in mining equipment which encompasses a wide range of machinery used in the extraction of minerals and resources from the earth. Currently, gears in c equipment are prone to a different types of failures when they are subjected to impact, shock and fatigue loads. It is noticed from the literature that 34.4% of the failures are due to poor lubrication, 19.6% due to impurity, 17.7% due to fixing errors, 6.9% are due to excess load and 2.8% failures are due to handling errors. Further, more than 1,500 gear failures were examined throughout the investigation, and it was observed that tooth bending fatigue is the common mode, leading to tooth fracture at the root owing to bending stress. Bending stress developed at the tooth root can be minimized by modifying addendum of mating gears or the involute geometry. An additional alteration that is rarely used is to make the gear asymmetric or nonstandard. Therefore, in this research work attempts are made to generate non-standard spur gear tooth profile by varying pressure angle and profile shift using Matlab to estimate bending stress using FE software ANSYS. Bending stress calculated using the Lewis equation and FE analysis were compared to validate the FE procedure. It is noticed that bending stress was reduced to 42.14% by increasing the pressure angle from 200 to 400 without altering other gear parameters. Hence, the possibility of tooth break can be minimized with the use of non-standard spur gears.