公开(公告)号：US20170100766A1

公开(公告)日：2017-04-13

申请号：US15262650

申请日：2016-09-12

Applicant: OTICS CORPORATION

Inventor： Koki YAMAGUCHI ,  Eiichi NOZAKI ,  Hiroya TSUJI

IPC: B21D53/84 ,  B21K1/12

CPC classification number: B21D53/845 ,  B21D22/025 ,  B21K1/12

Abstract: A method of manufacturing a pipe member includes arranging a pre-pipe member between first and second dies, moving one of the first and second dies to be closer to another one and holding the pre-pipe member with first and second recess portions, by the moving of the one of the first and second dies, and pressing an outer peripheral surface of the pre-pipe member with first and second inner surfaces in a closed state of the dies. By the pressing of the outer peripheral surface of the pre-pipe member, reducing a diameter of a portion of the pre-pipe member and forming a reduction portion having a polygonal shape so that the reduction portion has a same number of outer surfaces as a total number of the first inner surfaces and the second inner surfaces.