Patent ID: 7000444

Claim:
A die apparatus for use in a press for forging a bevel ring gear from an annular blank, the die apparatus comprising first and second assemblies relatively moveable towards each other along a longitudinal axis, the first assembly having a first bolster, an annular tooth cavity and an ejection punch, both the annular tooth cavity and the ejection punch having a common axis coincident with the longitudinal axis, the annular tooth cavity is supported by the first bolster and has a shape that is the obverse of the shape of the teeth of the bevel ring gear and faces the second assembly, the ejection punch is moveable relative to the first bolster along the longitudinal axis and has a head that protrudes from the first bolster, characterized in that at least a portion of the head of the ejection punch has a shape that is the obverse of the shape of at least a portion of the bore of the bevel ring gear, the second assembly having a second bolster, an annular punch and an annular die element, both the annular punch and the annular die element having a common axis coincident with the longitudinal axis, the annular die element is moveable relative to the second bolster along the longitudinal axis and at least a portion of the shape of the annular die element has a shape that is the obverse of the shape of at least a portion of the outer surface of the bevel ring gear, the annular punch is supported by the second bolster and at least a portion, of the shape of the annular punch has a shape that is the obverse of the shape of at least a portion of the back of the bevel ring gear, the head of the ejection punch overlaps the annular punch, in the direction of the longitudinal axis, as the first and second assemblies move towards each other thereby forming a closed annular die cavity, and wherein during operation of the die apparatus, the annular blank is placed in the die apparatus and first and second assemblies move relatively towards each other until the annular blank is forged to the shape of the bevel ring gear.