| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a working method for making the end part of a tube thin precisely and stably without depending on machining and being accompanied with a reduction in the outer diameter. <P>SOLUTION: After holding the basic end part of a tube stock 10 to a chuck 21 in a chuck unit 20, a mandrel 11 having tip end side formed in a shape with step is force-fitted into the end part of the tube stock 10, and the tube end part is expanded. Thereafter, while rotating the tube stock 10 together with the mandrel 11 with a chuck unit 20 in the figure (d), one pair of roller-dies 22 is pushed to the outer peripheral surface of this tube end part, and successively, one pair of roller dies 22 in the figure (d) is parallel shifted along the tube stock 10 and the thickness of the tube end part is reduced by performing a rotation-ironing with the roller dies 22 and the mandrel 11, and while maintaining the outer diameter of the tube stock 10 in the figure (f), the inner surface is finished into a multi-stage shape, similar to the multi-stage forming part of the mandrel 11. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
