公开(公告)号：EP4257841A1

公开(公告)日：2023-10-11

申请号：EP21903064.0

申请日：2021-11-02

Applicant: NHK Spring Co., Ltd.

Inventor： NISHIZAWA, Shinichi ,  MORIYAMA, Senri ,  DAI, Fang ,  FURUSE, Takeshi

IPC: F16F1/06

Abstract: According to an embodiment, a coil spring includes a wire rod (2) having an end and the other end. The wire rod (2) of the coil spring includes, with regard to a section of the wire rod (2), a round section potion (30) of an effective spring part (13), a square section portion (31) in which the section is substantially square, and a taper portion (32). The square section portion (31) includes an end turn part (11)(12). A length of each side of the section of the square section portion (31) is less than or equal to a square root of 1/2 multiplied by a diameter of the wire rod (2) of the round section portion (30). In the taper portion (32), from the round section portion (30) to the square section portion (31), the section changes from a round shape to substantially a square shape, and a sectional area is decreased.