Patent ID: 7677073

Claim:
A method of manufacturing a gear, by cold-forging, a gear having a finished gear tooth profile, comprising the steps of: in an initial cold-forging step, cold-forming a preform to produce a gear element having a first gear tooth profile of a first tooth thickness; in an intermediate cold-forging step forming a gear element of a second tooth profile, following the initial cold-forging step, using a die having a surface with a die tooth profile extending from an opening at one end to a second end, opposite the one end, pressing the gear element with a punch or pin into the opening of the die and axially along the surface with the die tooth profile, whereby, before the gear element reaches the second end, without a reduction in the tooth thickness of more than 10% of the first thickness, a dedendum portion of the gear element including bottom lands of the tooth profile is pressed radially inward and an addendum portion of the gear element is caused to expand radially outward, wherein when the gear element reaches the second end (1) tooth thickness of the teeth of the second tooth profile remains substantially identical to the first tooth thickness or the tooth thickness of teeth in the second tooth profile is reduced no more than 10% of the first tooth thickness and (2) spaces remain between the outer tips of the teeth of the second tooth profile of the expanded addendum portion and the die tooth profile; and a sizing step, following the intermediate step, wherein the gear element is finished to have the finished gear tooth profile.