Experimental investigation of power loss in altered tooth sum gearing

Joseph Gonsalvis, H. R. Prakash, H. K. Sachidananda

Abstract

Gears are the most efficient power transmission elements. Power loss in transmission is an important parameter which determines the efficiency of the system. The tooth action from the beginning to the end of contact along the path contact consists of slide/ roll motion, while rolling being predominant at the pitch point, sliding takes its share at the begin and end points. The coefficient of friction is higher during approach compared to the recess; therefore power loss in gearing can be regulated by designing gears to maintain tooth action which will lower the power loss. Altering the toothsum of a gear pair working between a specified center distance and module introduces profile shift, which can be used effectively in designing gears for higher efficiency. Unlike other types of gearing the altered tooth-sum gearing provides a greater amount of freedom in using large values of profile shift which is commonly not in use. The alteration in number of teeth can be varied up to ± 4% of tooth-sum. This paper presents about the methods to select the number of teeth to be altered on a tooth-sum and to use the resulting profile shift coefficients to obtain tooth action which lowers the sliding power loss. Few cases of altered tooth-sum gearing are considered for experimental investigations for a tooth-sum of 100 to demonstrate the proprieties of altered tooth-sum gearing. The findings indicate clearly that altered tooth-sum gearing can be employed in designing gears to achieve higher efficiency.

Keywords

Profile shift; Operating pressure angle; contact ratio; path of contact; power loss; efficiency

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IMEKO-TC14-2007-46.pdf

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IMEKO TC

TC14 - Measurement of Geometrical Quantities

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