Performance of Gears | Nature

ABSTRACT IN a paper by Messrs. Hyde, Tomlinson, and Allan, of the National Physical Laboratory, read before the Institution of Automobile Engineers on April 4, an interesting account was

given of researches which have been in progress at the Laboratory during the past few years on the performance of gears. The best gears are made of special alloy steels, either air or oil

hardened, and afterwards finished to an accuracy of a few ten-thousandths of an inch by grinding. The work of the Laboratory shows that such gears can transmit power with the very high

efficiency of more than 99 per cent. At the high speeds of rotation to which gears are subjected, a tooth out of its true position by less than a thousandth of an inch may come into mesh

with a shock sufficient to double or treble the normal pressure on the tooth. Although it has ample strength to withstand this augmented pressure as a steady load, if the effect is repeated

often enough the metal becomes fatigued, and the tooth may ultimately break off as a result of this fatigue. Thus the fatigue strength should be the criterion employed in design, rather than

the more usual considerations of static strength and durability. The experiments further showed that this type of gear can be run under load for many millions of revolutions with scarcely

any appreciable wear of the tooth faces, presupposing the best conditions of lubrication. It appears as though the lubricating oil, when functioning efficiently, almost completely holds the

steel surfaces apart by a highly tenacious film. Another feature of interest is that even ideally perfect gears must lose some of their running perfection when it is necessary for them to

transmit power under heavy loads. This is due to the small elastic bending of the teeth caused by the heavy load, which has the effect of disturbing the perfect uniformity of the motion

which the gear would otherwise transmit. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS OPTIONS Access through

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Read our FAQs * Contact customer support RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Performance of Gears. _Nature_ 129, 538–539 (1932).

https://doi.org/10.1038/129538d0 Download citation * Issue Date: 09 April 1932 * DOI: https://doi.org/10.1038/129538d0 SHARE THIS ARTICLE Anyone you share the following link with will be

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