抄録
The purpose of this research aims at practical use of the concave conical gear. Tool to generate concave conical gear is not a straight rack but also a conical-shaped wheel. This conical-shaped wheel is realized imaginarily, and this is called a "imaginary conical-shaped wheel". In this paper, first the characteristic of involute hob is demonstrated, and the hob helicoid is defined. This imaginary conical-shaped wheel is obtained as enveloping surface of the hob helicoid in anti-crowning motion. Secondly, the hobbing method for helical concave conical gear is developed, based on the generating method. Finally the helical concave conical gears are made for trial. Tooth surface of the test gears are measured and compared with theoretical ones. Both tooth surfaces are in good agreement.
