公开(公告)号：US20250114838A1

公开(公告)日：2025-04-10

申请号：US18729272

申请日：2022-11-10

Applicant: JFE STEEL CORPORATION

Inventor： Shunsuke TOBITA

IPC: B21D22/26 ,  B21D24/00

Abstract: A press forming method of forming a press formed part including: a top portion having a convex peripheral edge having a whole of or part of an outer peripheral edge curved outward in a convex shape; a side wall portion continuous to the top portion via a punch shoulder R portion; and a flange portion continuous to the side wall portion via a die shoulder R portion, the method includes: (a) forming a metal sheet into a preformed part; and (b) forming the preformed part formed in (a) into the press formed part having a target shape, wherein (a) performs forming such that a bending radius of the die shoulder R portion formed corresponding to at least the convex peripheral edge of the top portion of the preformed part is larger than a bending radius of the die shoulder R portion of the press formed part having the target shape.

公开(公告)号：US20230087377A1

公开(公告)日：2023-03-23

申请号：US17798771

申请日：2020-10-02

Applicant: JFE STEEL CORPORATION

Inventor： Yusuke FUJII ,  Masaki URABE ,  Shunsuke TOBITA

IPC: G06F30/23 ,  B21D22/24 ,  B21D22/26 ,  B21D22/30

Abstract: A shape change prediction method for a press formed part for predicting a shape change of the press formed part with a lapse of time units after springback at a moment of a release from a die includes: a shape/residual stress immediately after springback acquisition step of acquiring a shape and a residual stress of the press formed part immediately after the springback by a springback analysis of the press formed part; a residual stress relaxation/reduction setting step of setting a value of a residual stress relaxed and reduced from the acquired residual stress to the press formed part immediately after the springback; and a shape analysis step of determining a shape, in which moments of force are balanced, for the press formed part to which the value of the relaxed and reduced residual stress is set.

公开(公告)号：US20240042505A1

公开(公告)日：2024-02-08

申请号：US18265910

申请日：2021-08-06

Applicant: JFE STEEL CORPORATION

Inventor： Yusuke FUJII ,  Masaki URABE ,  Shunsuke TOBITA

IPC: B21C51/00 ,  B21D22/26

CPC classification number: B21C51/00 ,  B21D22/26

Abstract: A shape change prediction method of a press formed part predicts a shape change in which an end side in a longitudinal direction is twisted due to stress relaxation with a lapse of time after springback at a moment of die release from a tool of press forming with respect to the press formed part having a U-shaped cross-sectional shape including a top portion and side wall portions, and includes: acquiring a shape and a residual stress of the press formed part immediately after the springback by a springback analysis of the press formed part; setting a value of stress relaxed and reduced compared to the residual stress immediately after the springback for at least one of the side wall portions; and acquiring a shape with which moment of force is balanced for the press formed part in which the value of the relaxed and reduced stress is set.

公开(公告)号：US20230100401A1

公开(公告)日：2023-03-30

申请号：US17799782

申请日：2020-10-02

Applicant: JFE STEEL CORPORATION

Inventor： Yusuke FUJII ,  Masaki URABE ,  Shunsuke TOBITA

IPC: B21D22/26

Abstract: A press forming method for controlling a shape change of a press formed part over time after the press formed part springs back at a moment of a release from a press-forming die includes: a press forming step of press forming a metal sheet into the press formed part by using the press-forming die; a die releasing step of releasing the press formed part, which is press-formed, from the press-forming die; and a post-release die holding step of holding the released press formed part in a forming bottom dead center shape for 30 minutes or more by using the press-forming die.