| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a forging crankshaft capable of providing the forging crankshaft for simultaneously attaining weight reduction and rigidity security.SOLUTION: A manufacturing method includes a die forging process of providing a burred forcing material of molding a shape of a crankshaft, a deburring process of providing a non-burr forging material 30 from the burred forging material and a push-in process of molding a recessed part Au by pushing a second metal mold 22 in a pin part side surface after drafting the non-burr forging material 30 by a pair of first metal molds (11 and 12), and in the die forging process, first surplus thickness parts (Aca and Ada) projecting from the outer periphery of both side parts (Ac and Ad) in the vicinity of a journal part J, are further molded, and in the push-in process, when drafting the non-burr forging material, the first surplus thickness parts (Aca and Ada) are crushed by the first metal molds (11 and 12), and a thickness of both side parts (Ac and Ad) in the vicinity of the journal part J is increased, and the recessed part Au is molded between mutual both side parts (Ac and Ad) in the vicinity of the journal part J among the pin part side surface.SELECTED DRAWING: Figure 11 |
