Electronic Theses and Dissertations




Srijana Shah



Document Type


Degree Name

Master of Science


Mechanical Engineering

Committee Chair

Hsiang Hsi Lin

Committee Member

Teong E. Tan

Committee Member

John I. Hochstein


One of the major concern in the design of power transmission gear is the reduction of gear dynamic load. Research on gear noise and vibration has revealed that the basic mechanics of noise generated from gearing is gear box vibration excited by the dynamic load. This thesis studies the effect of tooth spacing errors on the dynamic load of high contact ratio spur gear subjected to unideal loading conditions. Spur gear is the simplest kind gear available. Spur gears have their teeth parallel to the axis of rotation and are used for transmitting power between two parallel shafts. Three types of spacing error distribution are defined and studied: type I (short span), type II (medium span), and type III (long span). Three different kinds of modification have been considered: linear, parabolic 1, parabolic II. The range of loading is changed from 0.75 times to 1.25 times of design load which is 2200 lb.-inch. A computer simulation has been conducted to investigate the effectiveness of profile modification for reducing dynamic loads in high-contact-ratio gears with different tooth spacing errors. The simulation examined varying amplitudes of spacing errors and differences in the span of teeth over which the errors occur. The dynamic analysis was performed using a revised version of a NASA gear dynamics code, modified to take into consideration the tooth spacing errors in the dynamic analysis. The findings of this study can be used to design robust tooth profile modification for improving the dynamic performance of high-contact-ratio gear sets with different tooth spacing errors when subjected to unideal loading condition.


Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.