公开(公告)号：US11371575B1

公开(公告)日：2022-06-28

申请号：US17113438

申请日：2020-12-07

Applicant: NHK SPRING CO., LTD.

Inventor： Shinichi Nishizawa ,  Senri Moriyama ,  Fang Dai ,  Takeshi Furuse

IPC: F16F1/04

Abstract: According to an embodiment, a coil spring includes a wire rod having an end and the other end. The wire rod of the coil spring includes, with regard to a section of the wire rod, a round section portion of an effective spring part, a square section portion in which the section is substantially square, and a taper portion. The square section portion includes an end turn part. A length of each side of the section of the square section portion is less than or equal to a square root of ½ multiplied by a diameter of the wire rod of the round section portion. In the taper portion, from the round section portion to the square section portion, the section changes from a round shape to substantially a square shape, and a sectional area is decreased.