214 Geometrical Design of Point-Contact Face Gear

Face gears can be substituted for bevel gears or hypoid gears. They can be used only in restricted applications today. Recently, a new application of face gears for helicopter transmissions has been proposed and face gears have attracted special interest. The geometrical design method for face gear was also clarified. Especially, it has become clear how the inner and outer diameters of ring gear are defined. In this paper, for avoiding the influence of machining and assembling errors on tooth bearing, the design method of point-contact face gear is described. Concretely, the gear tooth surface is generated by the cutter gear with the same module as and larger number of teeth than the pinion. It was shown that the contact point was able to be located in a preferable place on the gear tooth surface by the appropriate choice of the addendum modification coefficient of the cutter gear. By tooth contact analysis on the example of designing gear, the effectiveness of the design method was confirmed.