A Study of the Efficiency of a Double-Action Worm Gear Set

Abstract

A double-action worm gear set—so called because the worm has both rotational and longitudinal degrees of freedom—has been invented primarily for use in a motorized spacecraft hinge. This paper presents an analysis of the mechanical efficiency of the double-action worm gear set, together with preliminary test results. Results of analysis and test show that the double-action feature of the worm makes it possible to control the forward and backward driving efficiency of the gear set. Compared to a standard worm gear set, the double-action worm gear set has the advantages of the ability to absorb small applied displacements to the wormwheel shaft in an unlocked position, the ability to be non-backdrivable with a high degree of certainty when locked against an end stop and the ability to maintain a specific preload in a locked position.