| 摘要 |
PURPOSE:To reduce variance in the shape of a reference hole, and to prolong the life of a punch, etc., by forming the reference hole in cylindrical parts at a prescribed flank position from its side, and then piercing a hole connecting to the reference hole from the side after press-forming a stepped part. CONSTITUTION:A ram R is moved down to slide a punch 7 in a direction A, piercing a reference hole 8 in a flank of cylindrical parts 5. Then, the ram R is moved up to return the punch 7 to its original position. The cylindrical parts 5 having the reference hole 8 are covered on a punch 10, and pressed by a pad 11 conforming to the normal upper outward shape of the cylindrical parts. A die 12 conforming to the normal outward shape of the cylindrical parts is lowered to form a stepped part 5a by press work. In another stage, an angled hole 13 connecting to the reference hole 8 is pierced to obtain desired cylindrical parts. |
