Spherical gear coupling design space analysis for high misalignment applications

Abstract

Spherical gear couplings are machine elements that enable power transmission between highly misaligned shafts. The highly crowned tooth surfaces and the presence of undercut sections, have been a matter of disagreement between existing geometry generation methods available in the scientific literature. The main reason for this, are the geometry variations which arise in the generated parts, and consequently, the effect of such variations on the contact point location and clearance distribution. In this paper the influence of the main design parameters of spherical gear couplings (namely, the crowning ratio, the pitch diameter, the pressure angle, etc.), on the geometrical properties of the gear tooth surfaces are investigated. An algorithm to calculate the maximum misalignment angle is proposed, which is one of the most crucial design parameters. It shows that the values obtained with models existing in the literature are not applicable to highly crowned spherical gear couplings. Finally, design criteria are described to help the designer choose proper spherical gear coupling tooth geometry parameters to fit in a certain space and achieve a given maximum misalignment angle without further geometrical issues (undercut or pointed teeth).