| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing a preform for forging a connecting rod having a large end part, a small end part and a rod part between the large and small end parts. SOLUTION: A lower die equipped with a plurality of segmental dies 103 capable of opening and closing comprising a chucking part 103a that constrains a shank part W'c of the preform material and a formed part of an upper edge that coincides with the shape of an undercut part at the side of the shank part W'c of the block part W'b for the small end is progressed in order to a plurality of forging press. The axial length and diameter of a wide-opened part 110a, 120a, 130a and 140a are extended and enlarged in order from an upper die of a fore-standing forging press station toward that of a rear-standing press station by setting an upper punch 150 having a formed part 150a that coincides with the shape of a part other than the undercut part of the block part for the small end to a rearmost-standing forging press station, by setting the upper die 110, 120, 130 and 140 that is installed at the outside of an extended part W'd and a forging press punch 111, 121, 131 and 141 to the remaining press stations, and by forming the wide-opened part 110a, 120a, 130a and 140a at an inner periphery of a lower part of each upper die.
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