Patent attributes
A closed forging die and a forging method with which sagging can be reduced, a constant velocity joint and a universal joint can be made compact and lightweight, removal of a shaft tip thereof by machining prior to heat treatment is not required, and material costs and machining costs can be reduced by using a closed forging die includes openable dies, and punches that move in an opening/closing direction of the dies to pressurize a material in the dies. By using the die, a product having shaft portions formed radially is manufactured. A clearance is provided to each of the formed shaft portions between a tip surface, and abutting portions are provided to the dies side abutting against at least a tip side of an outer circumferential surface of the shaft portions.
