Effect of Change of Spur Gear Tooth Parameters on Bending and Contact Stresses
No Thumbnail Available
Date
2014-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
The bending and surface stress of the gear tooth is considered to be one of the main contributors
for the failure of the gear in a gear set. After the investigation of shot peening to increase the
tooth bending strength and surface durability in gears, the surface roughness generated during
shot peening leads to macro and micropitting is now considered the dominant restriction on gear
life and performance. Thus, analysis of stresses has become popular as an area of research on
gears to minimize or to reduce the failures and for optimal design of gears. This thesis
investigated the effect of tooth parameters monitoring the stresses induced on spur gear by
optimizing face width, root fillet radius, and number of teeth relative to weight of spur gear set.
The involute profile of Spur gear has been modeled and the simulation was carried out for the
bending and contact stresses. To estimate bending and contact stresses, 3D models were
generated by modeling software CATIA V5r16, simulation was done by finite element software
package ANSYS 12.0, and optimization was done using Design Expert Dx7 numerical
optimization method. Analytical method of calculating gear bending stresses uses Lewis and
AGMA bending equation. For contact stresses Hertz contact equation are used. The Study was
conducted by varying the face width, number of teeth and root fillet radius to find its effect on
the bending and contact stress of spur gear. It was therefore observed that the maximum bending
stress and contact stress decreases with increasing face width, number of teeth and root fillet
radius relative to spur gear set weight. Using the Design expert software Dx7 the optimal points
were selected at face width 37.24mm, root fillet radius 3mm, and number of teeth 22.At these
value contact stress was reduced from 389.31Mpa to 294.56Mpa (24.34%) and bending stress
was reduced from 105.14Mpa to 49.65Mpa (52.80%).So that, it is recommendable to use optimal
values of tooth parameters during design work to reduce stresses. It means stress reduction
results in better tooth root load capacity, micropitting resistance, prolongs gear service life.
Description
Keywords
Mechanical Design Stream