Patent ID: 7337647

Claim:
A method for manufacturing a gear, wherein said gear is formed in a forging process by a first die having an inner peripheral surface on which a plurality of top surfaces corresponding to a bottom surface of said gear and projected side surfaces, corresponding to tooth surfaces thereof and sandwiching said top surface, connect smoothly to each other, said tooth surfaces and said bottom surfaces of said formed gear connect to each other smoothly, and wherein projected tooth surfaces of said formed gear are initially formed by movement of a first die having an inner peripheral surface to form a projected tooth profile compared with a final tooth profile of said gear, said inner peripheral surface of said first die has a concave part radially concave at a central part between parts of said inner peripheral surface corresponding to a tooth root side part and a tooth tip side part of said near tooth surface, and said projected tooth surfaces of said gear are finally formed by a second die having an inner peripheral surface configured to form final tooth surfaces of said gear corresponding to a final tooth profile of said gear.