| 摘要 |
PURPOSE:To provide a method for producing a curved pipe, whereby a curved pipe can be molded into a specific curved shape in a molding stage without causing ununiformity in wall thickness and a need of inserting or extracting a material over or from a mandrel. CONSTITUTION:A molding opening 18 peripherally uniform in opening width is formed between a fixed die 14 disposed in a top part 10 of an extruder and a core 16. A path forming member 22 is disposed adjacently thereto. A throttling part 52 is formed in the path forming member 22. By shifting the position of an outer member 32 at right angles to its axial direction, the width of the ring path at the throttling part 52 is peripherally changed. The extrusion amount of an extruding material extruded through the ring path 34 peripherally continuously formed is peripherally changed by the throttling action of the throttling part 52. In this manner, the extruding speed of the extruding material extruded from the molding opening 18 is peripherally varied, whereby a pipe extruded from the molding opening 18 is shaped into a curved form. |
