| 摘要 |
A method is provided for forming a one-piece sheet metal toothed wheel including a central sheet metal wall of predetermined thickness and a series of integral teeth on the periphery of the central wall. The method comprises a combination of steps the initial one is cold-forming a circular piece of sheet metal into a preform having an outer annular section of generally uniform cross-sectional configuration and an integral sheet metal central wall. The next step is rotating (1) the rotary holding unit with the preform secured thereto about the preform axis, and (2) the tooth-forming tool unit about the rotational axis thereof in a predetermined rotational relation wherein the axes are parallel and the rotational speeds are synchronized. The third step is performed while the rotary holding unit with the preform secured thereto and the tooth-forming tool unit are in the predetermined rotational relation, effecting a relative movement between the units and the axes thereof in a direction toward one another to engage the tooth-forming periphery of the tooth-forming tool unit in cooperating metal-deforming relation until the sheet metal of the outer portion of the annular section is cold-formed into a series of initially-formed teeth, peripheries of the series of initially-formed teeth being cold-formed by rolling contact with the tooth-forming periphery of the tooth-forming tool unit. Each of the initially-formed teeth has a pair of oppositely disposed operative surfaces defined between a crest portion and a trough portion. The final step is to form the series of integral teeth by removing material from the pair of operative surfaces.
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