COMPOUND SCREW BODY FORM-ROLLING DIE STRUCTURE, COMPOUND SCREW BODY ADJUSTING DIE STRUCTURE, COMPOUND SCREW BODY FORM-ROLLING METHOD, AND COMPOUND SCREW BODY ADJUSTING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce a rolling failure with respect to a columnar screw material when forming a compound screw body, and enable mass production of a highly precise compound screw body.SOLUTION: A form rolling of a compound screw body D is performed by using a die member 10 having a relatively displaced rigid surface while press-contacting to a screw material B. The die member 10 forms an approximate parallelogram shape in a normal line direction view of a virtual surface 22 obtained by fastening between surface outermost parts. Two or more recesses 30 recessed from the virtual surface 22 include a compound screw part forming area U plurally arranged along a relatively displaced direction. Furthermore, the die member 10 is disposed in the upstream side and/or the downstream side in the compound screw part forming area U. Adjustment valleys 61, 62 extending in a strip shape and recessed on the virtual surface 22 is configured to have a compound screw part coordination area N tilted and formed by a lead angle of the compound screw part forming area U.