| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of a crack in a broken-out section.SOLUTION: A semifinished product of a connecting rod is introduced into a broken-out separation process in which a big end 14 is expanded in a radial direction to be broken out and separated into a body part 16 and a cap part 17. The semifinished product includes a notch 25 formed in an inner peripheral surface 24 of a crank pin hole 13 arranged in a central part of the big end 14 and served as a generation origin of a crack C in the broken-out separation, and a stepped portion 23 formed in an inner peripheral surface of a bolt hole 18 provided in both ends of the big end 14 and through which the crack C progresses and passes in the broken-out separation. |
