The authors have developed the analytical geometry of face-gear drives, proposed the method for localization of bearing contact, developed computerized simulation of meshing and bearing contact, investigated the influence of gear misalignment on the shift of bearing contact and transmission errors. Application for design is discussed. The obtained results are illustrated with numerical examples.

The use of face-gears in helicopter transmissions was explored. A light-weight, split torque transmission design utilizing face-gears was described. Face-gear design is discussed. Topics included basic design geometry, tooth generation, limiting inner and outer radii, and recommendation for the gear ratio. Face-gear experimental studies were also included and the feasibility of face-gears in high-speed, high-load applications such as helicopter transmissions was demonstrated. Torque-split tests were performed and demonstrated an accurate split of torque using the face-gear concept.

The contents of the paper cover the determination of conditions: (i) of nonundercutting by axial and axial-radial generation of internal gears by shapers, and (ii) avoidance of interference by axial and axial-radial assembly. The authors have developed computer programs for simulation of undercutting and interference, design charts and a table that allow to determine the limiting number of teeth of the cutter and pinion considering the tooth number of internal gear as known. The details of developed algorithms are given in the Appendices. The paper is illustrated with computer graphics and numerical examples.