| 摘要 |
PROBLEM TO BE SOLVED: To provide a hollow extrusion molding device and a hollow extrusion molding method which can reduce a load acted on a sleeve punch, and can increase a degree of freedom of a product shape.SOLUTION: A hollow extrusion molding device 100 includes: a mandrel punch 30 inserted in a hollow part Wo of a workpiece W; a die 10 which has a molding part for inserting the workpiece W and a tapered part 13 formed in a middle part of the molding part; and a sleeve punch 20 for pressing the workpiece W inserted in the molding part. The workpiece W with the mandrel punch 30 inserted in the hollow part Wo is inserted in the molding part of the die 10, and the workpiece W inserted in the die 10 is pressed by the sleeve punch 20 to mold the workpiece W. A tapered part 33 is formed in a middle part of the mandrel punch 30. The mandrel punch 30 has a diameter which generates a clearance with an inner circumferential surface of the workpiece W when inserted in the workpiece W before molding. |
