Abstract
In this research, it is not a gear of circular arc tooth profile, but a gear of circular arc tooth line that we named a circular arc gear. Therefore the profile has an involute curve as ordinary ones. Such a circular arc gear can be used as a double helical gear which transmits the power smoothly without thrust force. There are some kinds of double helical gear planers or shapers of heavy type. But the tooth profile of the double helical gear can not be ground, as its tooth line is not suitable for grinding. With the gear generator, which the writer, K. Hasegawa invented ten years ago, we can cut a tiny arc gear, a precision type gear, which can be ground, although it has some points to be improved. The writers studied the characteristics of trial arc gear.
