Elliptic gear wheel

Abstract

An elliptic gear wheel or rotor having a predetermined pitch circle which includes longer and shorter radius and intermediary portions between said longer and shorter radius portions, the longer and shorter radius portions have teeth of a greater tooth pressure angle than that of teeth on the intermediary portion, and a transmission gear device including at least two identical elliptic rotors of the above type mounted in their respective support shafts in intermeshing relationship to each other. A method of producing an elliptic rotor in which the pitch line of a cutter and the pitch circle of said rotor move relative to each other in rolling contact to cut teeth on the longer and shorter radius portions of the pitch circle with a greater tool pressure angle and cut teeth on the intermediary portion of the pitch circle with a smaller angle, the meshing faces of the shorter radius and intermediate portions of the pitch line are provided with backlash grooves extending in the axial direction of the rotor and facing the longer radius portion. An apparatus for producing an elliptic rotor comprising a horizontal rotary cutter, a vertical rotary blank supporting shaft mounted on a carriage assembly movable horizontally with respect to the cutter, a rack integral with the carriage, a gear wheel mounted on a base member in meshing with said rack to move the rack as the gear wheel rotates and at least one elliptic rotor blank mounted on the shaft for rotation with the shaft in meshing relationship with the cutter.

Dependencies are inferred from the claim text.