To work the gear having the quality of a sound and small module and a high tooth depth by finishing/form rolling with the die having the tooth group of the prescribed pressure angle after roughly form rolling the object to be form rolled using the die having the tooth group of larger pressure angle than the prescribed pressure angle.
The object 6 to be form rolled is held between an upper and lower dies using a rough form rolling die 1, roughly form rolled at the form rolling speed of about 15000mm/min, and the object 6 to be form rolled without turning up is obtained. The object 6 to be form rolled after rough form rolling is held between the upper and lower dies in the same way as in rough form rolling using the finishing/ form rolling die, and finished/form rolled at the form rolling speed of about 15000mm/ min. Moreover, the addendum of biting tooth group of the finishing/form rolling die is preferably formed into about the same shape as the bottom of the object 6 to be form rolled after rough form rolling. By this way, the object 6 to be form rolled after rough form rolling becomes e.g. 9.80mm in the addendum circle diameter, e.g. 10.450mm in the addendum circle diameter just before finishing/form rolling completion, and the object 6 to be form rolled becomes high tooth depth at the time of completing finishing/form rolling, whereby the addendum circle diameter is allowed to be e.g. 10.800mm.
KUCHIKI TAKAYOSHI
SAITO TAKUMA
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