Method of forming a hollow profile molding extrusion die and the hollow shape member molding extrusion die

摘要

PROBLEM TO BE SOLVED: To provide an extrusion die for forming a hollow shaped material, the extrusion die being configured so that the extrusion die allows the extrusion at high speed, even of a billet, so that the durability of a mandrel is increased, and so that a high-quality product is obtained by minimizing the displacement of the mandrel in the rotational direction.;SOLUTION: An extrusion die 10 is configured so as to comprise: a male die 20 which forms the inner shape of a shaped material by extruding a billet B to the downstream side; and a female die 30 which forms the outer shape of the shaped material. The male die 20 is configured from a mandrel 22 and a holder 25 which holds the outer periphery of the mandrel 22. The mandrel 22 is formed from: a forming section 23 which forms the inner shape of the shaped material; and a bridge section 24 which supports the forming section 23 and which has a front end outer peripheral surface which engages with the inner periphery of the holder 25. Engagement surfaces between the front end outer peripheral surface of the bridge section 24 and the inner periphery of the holder 25 are formed as sloped surfaces configured so that the downstream side thereof in the extrusion direction is located closer to the center of the die. The extrusion die also comprises a rotational displacement prevention mechanism which prevents the rotational displacement of the mandrel relative to the holder.;COPYRIGHT: (C)2013,JPO&INPIT