公开(公告)号：US20210308740A1

公开(公告)日：2021-10-07

申请号：US17273923

申请日：2019-09-03

Applicant: NHK SPRING CO., lTD.

Inventor： Masaaki MAEDA

IPC: B21F35/00

Abstract: Provided are a forming method for an arc spring, capable of easily and surely locating bearing faces on both end faces of a semi-finished product in predetermined positions, the bearing faces having lengths within permissible ranges in a circumferential direction. For a semi-finished product prior to curving an axis, it is determined whether circumferential lengths of bearing faces on both end faces are respectively within the permissible ranges based on end face image information of the both end faces imaged in an axial direction prior to the curving, a circumferential rotational position of the semi-finished product capable of respectively locating the bearing faces within the predetermined positions is specified using the end face image information, and the semi-finished product is rotated to the specified rotational position, and the wedge part is sequentially driven into inter-wires of the semi-finished product to deform the semi-finished product.