US 12,280,416 B2
Hollow shell part manufacturing method
Shohei Tamura, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/923,525
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Jun. 18, 2021, PCT No. PCT/JP2021/023260
§ 371(c)(1), (2) Date Nov. 4, 2022,
PCT Pub. No. WO2022/014262, PCT Pub. Date Jan. 20, 2022.
Claims priority of application No. 2020-120785 (JP), filed on Jul. 14, 2020.
Prior Publication US 2023/0182191 A1, Jun. 15, 2023
Int. Cl. B21D 22/26 (2006.01); B21D 7/06 (2006.01); B21D 22/02 (2006.01); B21D 47/01 (2006.01); B21D 51/02 (2006.01)
CPC B21D 22/26 (2013.01) [B21D 51/02 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A manufacturing method for a hollow shell part, the method comprising:
obtaining a bent tube having a curved portion by at least bending an original tube, wherein the curved portion has a bend radius of equal to or more than a minimum bend radius R10min at which no buckling or wrinkles occurs, and
applying pressure to the bent tube having the curved portion from outside of the tube toward inside of the tube using a press die, thereby simultaneously performing cross-sectioning of the curved portion and bending of the curved portion to reduce the bend radius of the curved portion, wherein the bend radius of the curved portion is reduced to less than the minimum bend radius R10min.