The Design of a Novel Mechanical Transmission for Speed Reduction

Abstract:

The design of a novel transmission for speed reduction is reported in this paper. The transmission is based on the layout of pure-rolling indexing cam mechanisms, and hence, eliminates backlash and friction, which are the main drawbacks of gear transmissions. The design relies on a unified methodology for indexing cam mechanisms, whereby the same procedure is used to design planar, spherical, and spatial mechanisms. Two versions of the speed reducer, that we term Speed-o-Cam, are described here, namely, planar, to couple shafts of parallel axes, and spherical, to couple shafts of intersecting axes. By means of a cascade of two planar versions of Speed-o-Cam, moreover, coaxial shafts can be coupled. The proposed design thus eliminates the drawbacks of gear transmissions without bringing about those of harmonic drives or epicyclic transmissions, which nevertheless work only for coaxial shafts.