| 摘要 |
PURPOSE:To form a spiral groove deep and free from a flaw in the groove edge and groove wall by forming a spiral groove under the normal groove width and pitch at the 1st process and profile-forming a groove at the succeeding process basing on the formed groove. CONSTITUTION:A manufacturing equipment is constituted of cold-drawing die devices 1, 2. A die 4 of the device 1 is provided with a spiral-groove forming part 3 and is made rotatable around its axis. A free die 9, provided with a spiral-groove forming part 8 capable of forming a groove deeper than the forming part 3, is incorporated freely rotatably in the device 2, and is made forcibly rotatable around its axis. A standard spiral groove B is formed by drawing an original bar-material A through the die 4 while rotating the die 4. Next, the material A is passed through the die 9 to form deeply the groove B by the forming part 8 while profiling the groove B. At the 2nd process and subsequent operations, the die 9 is forcibly rotated by a torque motor 12 while compensating the amount of profile-resistance caused by profiling the spiral groove. |
