| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for improving the efficiency of forming a plurality of grooves that are formed on the inner circumferential face of a cylindrical member in the circumferential direction at some intervals. SOLUTION: An apparatus M is provided with: a rotary shaft 53, which is arranged inside a raw material W and rotatably supported by a 1st and a 2nd supporting stands 57, 58; positioning collars 61, 62, which position the raw material W to a position where the raw material W is worked and rotatably support the raw material W; a rotary die 54, which is arranged inside the raw material W and on which a plurality of projecting parts 54b are formed; and a roller 55, which is arranged outside the raw material W and on which recessed parts 55b are formed. A circumferential wall Wc is held in the radial direction between the rotary die 54 and the roller 55. When the rotary die 54 rotates around a rotation axis L2 parallel to the axis of the raw material W, each of the projecting parts 54b presses the circumferential wall Wc in the outward radial direction to push the wall into the recessed parts 55b, so that a group of grooves consisting of a plurality of communication grooves is formed. COPYRIGHT: (C)2006,JPO&NCIPI
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