| 摘要 |
PURPOSE:To provide the titled blank from which a connecting rod having no overlap can be produced by improving the yield of a material of which the metal in the part corresponding to at least the large end of the connecting rod is formed to a spherical shape or the shape resembling thereto by a rational and simple closed-die forging method. CONSTITUTION:The blank 10 for forging this connecting rod is formed to the shape of which the metal in the part 11 corresponding to the large end thereof is formed to a spherical shape or the shape (approximately spherical or polyhedral shape, etc.) resembling thereto. The metal in the part 12 corresponding to the small end is preferably made into the similar shape. An I section part 4 is made to the shape having the metal enough to be filled in the stage of closed-die forging and is preferably of a circular cylindrical shape. Upper and lower punches 6a, 6b, 7a, 7b are first fixed to the retreat position of the stroke shown in the figure and thereafter the stock 10 is imposed between upper and lower dies 5a and 5b and is press-welded by the dies 5a, 5b by which the part 4 is formed to the prescribed shape. While the dies 5a, 5b are closed, the stock is compressed by the punches 6a, 6b, 7a, 7b by which only the large end 11 and small end 12 are formed to the prescribed shapes. |
