| 摘要 |
PURPOSE:To provide the titled work which decreases the piping defect in the annular corner part of the base thereof, has a long effective tooth length and prevents the deterioration in the rigidity of the pulley in the corner part by forming a rough surface constituting a resistance element in the press direction to the inside peripheral surface of the work. CONSTITUTION:A disk-shaped blank material made of a steel plate is supplied into a counter punch 20. The peripheral edge of the blank is dranw to a cup shape by an upper die 16 when a main punch 18 formed with a tooth profile 182 on the outside peripheral surface is lowered. The vally of the product is pushed toward the center along the tapered surface of a lower die 14 formed with a tooth profile 141 corresponding to the tooth profile 182, by which the ruggedness of the tooth profile shape is formed on the outside periphery of the product. The peak of the tooth profile 182 of the punch 18 is formed with multiple stages of straight beads 182a in the direction intersecting orthogonally with the blanking direction of the press. The beads 5a conforming to the shape of the beads 182a are thus formed to the inside of the peak of the product tooth profile 5. The ends of the beads 182a bite to the inside surface of the material, by which the excessive material flow is prevented and the piping defect at the corcner is prevented. |
