A STUDY ON AN OPTIMIZED DESIGN OF . A NONSTANDARD HELICAL GEAR PAIR FOR DIFFERENT GEAR MATERIALS

Abstract

The work presented in 'this dissertation deals with the optimization of•a non-standard helical gear set for different material combination of pinion and gear. Attention is focused upon reducing the volume of a gear set subjected to constraints on bending stress, pitting stress and involute interference. Before proceeding to the actual design and optimization .aspect, a brief review is done on the work of similar nature that was done by experimentalists and designers in the past. The review indicates that precise gear-ratio specification often makes it difficult or even impossible, to produce a workable planetary gear combination with standard gears. This is particularly true where space limitations must also be considered. Special centre distance, volume (or weight) or gear ratio's of ordinary gear combinations are equally impossible with standard gears. Non-standard gears can overcome such limitations. A lot of work has been done in case of standard gears but no such work has been reported on the optimization of non-standard helical gear-pairs for different gear material combination. The present work, is directed towards the optimization of a non- standard helical gear pair. The non-standard gears are generated through shifting of the cutter profile, which depends on the input parameters. The two different systems namely So-gearing and S-gearing which are normally used in non-standard gearing are undertaken in this work. An attempt has been made to examine the mode of failure of various material combinations at different input torques. The effect of gear ratio on pinion volume is also studied at different input power and speed combinations for various material combinations. (