| 摘要 |
PURPOSE:To forge a connecting rod product free from fins in closed state from a preformed material by forming the preformed material provided with large and small spherical parts on both ends of a blank bar material, forming a yoked-shape with pressing a large spherical part by a side punch after closing with upper and lower metal molds, and pressurizing with double acting by upper and lower punches while restricting. CONSTITUTION:The preformed material 1 provided with the large and small spherical parts 2, 3 is formed by an electric upsetter on both ends of small diameter blank bar material corresponding to the rod part of the connecting rod. Then the whole preform body is heated to set between the upper and lower metal molds 11, 12 and to close the molds, then the side punch 51 is advanced. The large spherical part 2 is initiated to form the yoked-shape by the penetration of the semi-spherical projecting part 52 of this side punch 51. Then, the upper and lower punches 31, 41 are operated double acting while holding the side punch 51 by the large end part of the molds 13, 23. The preformed material 1 is them subjected to squash forming from up and down sides to form the connecting rod product in finish forging. |
