Method of manufacturing a spur gear by cold forging

摘要

PROBLEM TO BE SOLVED: To provide a cold-forged component, which does not require a substantial correction to a tooth surface or a cam surface made by cutting after cold-forging, avoids excessive working load, and is further mass-produced as a component having high accuracy and little non-uniformity by a simple work after cold-forging, and to provide a method for manufacturing the same.;SOLUTION: A cold-forged component is manufactured by cold-forging a member to be worked with a first pressing means (a punch) and a second pressing means (a nockout) inside the inner circumferential surface of a die. Clearances for protrusion are set between the inner circumferential surface of the die and the outer circumferential surfaces of the first pressing means (a punch) and the second pressing means (a nockout) over the entire circumference. When conducting cold-forging, the outer circumferential edge part of the cold-forged component is protruded into the clearance for protrusion along the inner circumferential surface of the die over the entire circumference, so that burrs or pads are formed on the whole circumference of the outer edge part of the cold-forged component. When a pin is used as a third pressing means, the outer circumferential edge part of the cold-forged component is protruded into the clearance for protrusion along the inner circumferential surface of the die over the entire circumference, so that burrs or excess metal is formed on the whole circumference of the outer edge part of the cold-forged component.;COPYRIGHT: (C)2009,JPO&INPIT