Development of Harmonic Drive Combining Four Arcs for Conventional Kinematic Application

Abstract

This paper proposes a modified harmonic cam, which is used to design a harmonic drive. Conventional harmonic drives using a sinusoidal cam type pertain to an elastic body concept and are thus difficult to design and evaluate. Unlike the conventional sinusoidal cam, the proposed harmonic cam involves a combination of four arcs. Such cams can be designed based on a rigid body concept, and thus, the tooth profile can be designed and analyzed using the established gear theory. The novel harmonic cam is designed by exploiting four-arc combinations, and guides for designing harmonic drives with involute and cycloid angular teeth are presented. A harmonic drive with a difference of two teeth between the circular spline and flex spline is designed. The operation, tooth engagement, and interference are validated through a mock-up production using a 3D printer and gear simulation program. The findings can facilitate the facile design and manufacturing of harmonic drives.

Possibilities of Using Selected Additive Methods for the Production of Polymer Harmonic Drive Prototypes

“…New design solutions must be tested, preferably with prototypes, before deployment. For laboratory research, harmonics drives can be made quickly and cheaply from polymers using 3D-printing methods [10,11].…”

“…The harmonic drive has a very complicated design and a principle of work [3,10]. Its main components are the flexspline, the circular spline, and the wave generator, which are shown in Figure 1.…”