| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of bending work of a metal pipe reducible of a springback amount than before, simplifying work operation, and improving efficiency. <P>SOLUTION: In the method, the metal pipe is fitted in a pipe guide recess 21 formed on the outer peripheral surface of a roll block 2 of a pipe bender A, and the metal pipe 1 is pressed to a bend guide surface 20 in a semi-arc shape in cross section, thereby giving the bending work to the metal pipe 1. With respect to the roll block 2 used herein, a plurality of recessed grooves 22 formed on the bend guide surface 20 have depth deeper than or equal to a prescribed depth throughout the total length area in the height direction of the bend guide surface 20, and the both ends of the plurality of recessed grooves 22 are opened on the outer peripheral surface of the roll block 2 so that edge parts e1, e2 of the pipe guide recess 21 are formed into a recessed/protruded shape. On the inner side surface of the bend part 10 of the metal pipe 1, a plurality of protrusions 11 with substantially half the dimensional length of the outer periphery of the metal pipe 1, are formed. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
