DIE STRUCTURE FOR FORM ROLLING OF DOUBLE-THREADED BODY METHOD FOR FORM ROLLING OF DOUBLE-THREADED BODY AND THREAD MATERIAL FOR FORM ROLLING OF DOUBLE-THREADED BODY

摘要

Rolling of both bodies is carried out using a die member having a surface of rigidity that is relatively displaced while pressing against the screw material. The die member has a substantially parallelogram shape with respect to the normal direction of the imaginary surface obtained by connecting the outermost portions of the surface, and has a plurality of recessed portions spontaneously tapered from the imaginary surface, And a tapered portion extending in a belt-like shape on the virtual surface so as to be inclined by a lead angle with respect to a direction in which the tread tapering from the virtual surface is relatively displaced, And an uneven-thread forming region in which the thread is formed. As a result, it is possible to mass-produce both bodies having the threaded portion and the both threaded portions with high precision and efficiency.;