Nissan Motor Company Limited

Hideyasu Akiyoshi

Shigeo Murata

Fumitaka Nishimura

A rolling process for producing a spur gear. The process comprises the following steps: (a) bringing gear teeth of a generally wheel-shaped toothed tool into press contact with a peripheral portion of a generally wheel-shaped gear material at which portion gear teeth are to be formed; and (b) bringing gear teeth of a generally wheel-shaped backup roller into press contact with the peripheral portion of the gear material in course of formation of the gear teeth under rolling so that the gear teeth of the backup roller are to be in mesh with the gear teeth formed at the peripheral portion of the gear material under the action of the toothed tool. The backup roller has an inclined section for forming a chamfered portion of each tooth of the spur gear to be produced. The inclined section is located at a position corresponding to the chamfered portion of the spur gear.

Apparatus and method for forming a gear

A toothed wheel is cold formed from a circular piece or plate of sheet metal by cold-forming an annular outer section of the sheet metal into a preform, while the sheet metal is held in a rotary holding unit and rotated about its preform axis. While the sheet metal is rotating, a thickening roller works against the sheet metal's an outer annular section to thicken the same and form a wheel having a generally uniform cross-sectional outer annular section and an integral central wall that extends radially inwardly from the outer annular section. The outer annular section is formed by a multi-stage cold rolling process, utilizing different thickening rollers. Then, while the preform is rotating, a curling roller works on the outer annular section to form an axially extending flange, forming a cylindrical or C-shaped wheel to form a final preform. Then, while the final preform is rotating, a tooth forming roller is meshed against the outer periphery of the flange. At the same time, a back-up roller engages the flange at a different location to further shape the flange.

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Kameoka, Japan

Hideyasu Akiyoshi