| 摘要 |
The present invention provides 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, remove of a shaft tip thereof by machining prior to heat treatment is not required, and material costs and machining costs can be reduced. The closed forging die according to the present invention includes openable dies ( 11, 12 ), and punches ( 14, 15 ) that move in an opening/closing direction of the dies ( 11, 12 ) to pressurize a material in the dies ( 11, 12 ). By using the die, a product ( 16 ) having shaft portions ( 17 ) formed radially is manufactured. A clearance ( 26 ) is provided to each of the formed shaft portions ( 17 ) between a tip surface ( 17 a), and abutting portions ( 25 ) are provided to the dies side abutting against at least a tip side of an outer circumferential surface of the shaft portions ( 17 ).
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