公开(公告)号：US20240139798A1

公开(公告)日：2024-05-02

申请号：US18272231

申请日：2021-12-10

Applicant: HITACHI ASTEMO, LTD.

Inventor： Kinichi HASHIMOTO ,  Keisuke KITAMURA

IPC: B21K1/56 ,  B21K1/04

CPC classification number: B21K1/56 ,  B21K1/04

Abstract: A rolling machine has a rolling die 4 that forms a male screw by pressing a steering shaft 14 which is an object to be rolled and plastically deforming an outer peripheral surface of the steering shaft 14 while rotating in contact with the outer peripheral surface of the steering shaft 14, a main spindle 3 inserted into a penetration hole 10 of the rolling die 4 and transmitting a rotation force to the rolling die 4, a key groove and a key which restrict a relative rotation between the rolling die 4 and the main spindle 3, a spiral oil groove 16 provided on an inner peripheral surface of the penetration hole 10 or an outer peripheral surface of the main spindle and extending from one end portion 10b side in an axial direction of the penetration hole in an inner axial direction of the penetration hole.

公开(公告)号：US20240375170A1

公开(公告)日：2024-11-14

申请号：US18690433

申请日：2022-07-07

Applicant: HITACHI ASTEMO, LTD.

Inventor： Shinichi YAMANAKA ,  Daisuke HAMANAKA ,  Norihiro KIMURA ,  Keisuke KITAMURA

IPC: B21K1/76 ,  B21J5/02 ,  B62D3/12 ,  F16H55/26

Abstract: In a rack bar and a steering device using the same, an endmost tooth bottom for reducing a stress exerted on a first forging die during die forging of a rack tooth molding part is formed on the endmost side of a plurality of tooth bottoms. Specifically, the endmost tooth bottom is formed so that a depth thereof is less than a depth of an ordinary tooth bottom by a difference. This reduces an amount of flow of a material of the rack bar during formation of the endmost tooth bottom by an amount commensurate with the difference. As a result, the stress exerted on the first forging die can be reduced, and occurrence of heat checking in the first forging die can be suppressed.