CORE DIE FOR FORMING BEND AND REMOVING OF CORE DIE AFTER FORMING BEND

摘要

PURPOSE:To reduce drawing resistance and to improve accuracy of products by dividing a core die by a dividing face along the direction of curvature of the core die into two segmental core dies having different positions of center of gravity and drawing by turning each segmental core die turning them in opposite direction toward respective deviation sides of center of gravity. CONSTITUTION:In cross section of center axis of a core die, an imaginary face ABB'A' connecting two circles along the edge line of the core die that are drawn by setting perpendiculars Ra, Rb drawn from two points A, B at which an arbitrary center line passing the center Q of axis of the core die intersects the outer peripheral line of the core die as the center axis P-P' of curvature of the core die radius of curvature, and setting the center axis of curvature of the core die P-P' as centers. The core die for forming bend is bisected by a plane 4l which is made by rotating by optional angle making a line XlYl which is contained in the imaginary face ABB'A' and perpendicular to a tangent at any point on the circumference of a circle including the center axis OO' of the core die. These segmental core dies are rotated in opposite direction toward respective deviation sides of center of gravity and drawn by turning.