| 摘要 |
PROBLEM TO BE SOLVED: To provide a form rolling die for a screw having a full dog point which can prevent an outer circumferential surface of a work to be form-rolled from being slipped, and prevent the separation and breakage of a male screw or the like of a screw part of a shaft-like member caused by the slip. SOLUTION: In this form rolling die 1, when a screw part 21 of a screw component is form-rolled on the outer circumferential surface of the work by a permanent screw form rolling surface 2, a full dog point of the screw component is form-rolled by a full dog point form rolling surface 3, and a full dog point thread groove and a full dog point thread are formed on the full dog point part by a thread 5 for the full dog point and a thread groove 7 for the full dog point. Since the full dog point part of the screw component form-rolled by the full dog point form rolling surface 3 is form-rolled while the thread 5 for the full dog point and the thread groove 7 for the full dog point bite in the outer circumferential surface thereof, the shaft of the work is prevented from being slipped on an abutting surface on the full dog point form rolling surface 3. The permanent thread form-rolled on the outer circumferential surface of the work is not peeled by the slip, and the breakage of the screw part of the screw component can be prevented.
|
