PURPOSE: To manufacture a timing pulley made of steel sheet by one process, by providing tooth form on the inner periphery of a cylindrical die and on the outer periphery of a columnar punch and forming tooth form on the circumference from a cuplike material.
CONSTITUTION: When a dish-shaped material having a drawn fitting face is supplied on a counter punch 12, and a main punch 11 is lowered, the periphery of the material is drawn by an upper die 6 into cup-shape, and the trough part of the product is thrusted in toward the center by the conical slanted face of a lower die 5. The flow of the material on the conical slanted face 9 compresses the material while thrusting the material toward the crest side of the die. After giving plastic deformation to the material, the material is compressed by the trough side of the die 5 and crest side of the punch 11 to cause shifting of volume. Thus, forming of tooth form is completed.
YAMAZAKI SHIYOUICHI
MATSUNAGA SHIYUUICHI
| JPS57139432A | 1982-08-28 |