公开(公告)号：US20240335914A1

公开(公告)日：2024-10-10

申请号：US18293686

申请日：2023-04-26

Applicant: NSK STEERING & CONTROL, INC.

Inventor： Takeshi SAITO

IPC: B23P15/14 ,  B23P23/04 ,  C21D1/18

CPC classification number: B23P15/14 ,  B23P23/04 ,  C21D1/18

Abstract: Provided is a mechanical structural member that can suppress deformation and has high precision and excellent quality. In a mechanical structural member (triangular threaded shaft 31) in which grooves (32) and teeth (33) are formed by plastic working and a hardened layer (31a) is formed on a surface of the teeth (33), the mechanical structural member has a sorbite structure, and Rockwell hardness in a region P excluding the hardened layer (31a) is 13 to 28 (HRC). A variation in the Rockwell hardness in the region P excluding the hardened layer (31a) is within 6 (HRC).

公开(公告)号：US20240327943A1

公开(公告)日：2024-10-03

申请号：US18293713

申请日：2023-04-26

Applicant: NSK STEERING & CONTROL, INC.

Inventor： Takeshi SAITO

IPC: C21D9/00 ,  C21D1/10 ,  C21D1/18 ,  C21D6/00 ,  C21D8/00

CPC classification number: C21D9/0068 ,  C21D1/10 ,  C21D1/18 ,  C21D6/00 ,  C21D8/005 ,  C21D2211/008

Abstract: Provided is a mechanical structural member that can reduce deformation and has high precision and excellent quality. The mechanical structural member has a groove (32) and a tooth (33) formed by plastic working, and includes a hardened layer (31a) with a uniform martensitic single phase structure formed on a surface by induction hardening, a core region (31b) having a sorbite structure, and a boundary layer (31c) in which a sorbite structure and a martensite structure are mixed, formed between the core region (31b) and the hardened layer (31a). Rockwell hardness in the core region is 13 to 28 (HRC), and a variation in the Rockwell hardness is within 6 (HRC).