Method and press-forming apparatus for manufacturing structural member for automotive body

Patent metadata

Field	Value
Publication number	US-2016279692-A1
Application number	US-201414913851-A
Country	US
Kind code	A1
Filing date	Sep 10, 2014
Priority date	Oct 9, 2013
Publication date	Sep 29, 2016
Grant date	—

Abstract

To reduce the generation of cracking in the edge of the ridge flange ( 7 a, 7 b ) and wrinkling near the base of the ridge flange and can suppress an increase in the pad load, while press forming the structural member ( 1 ) that is made of a high-tensile steel sheet or a thick steel sheet and that has a substantially gutter-shaped cross section and an outward continuous flange in an end of the structural member.
A method for manufacturing the structural member ( 1 ), the method including: a first step in which the pad ( 15, 15 A, 15 B, 15 C, 21 ) presses the forming material ( 16 ) against the punch ( 13 ) to raise a portion corresponding to a flange to be formed in ends of at least the gutter bottom ( 2 ) and the ridge ( 3 a, 3 b ) in a direction opposite to the pressing direction, the pad ( 15, 15 A, 15 B, 15 C, 21 ) bends an end of a portion to be formed into the ridge ( 3 a, 3 b ) in the pressing direction and restrains at least a part of the end, and the punch ( 13 ) and the die ( 14 ) carry out press forming to form an intermediate product while a region other than an end in a portion to be formed into the gutter bottom ( 2 ) remains unrestrained.

First claim

1 . A method for manufacturing a structural member for an automotive body, the structural member being formed by pressing a forming material made of a steel sheet by using a press-forming apparatus having a punch, a die, and a pad facing the punch, the structural member extending in a predetermined direction, having a substantially gutter-shaped cross section intersecting the predetermined direction, and including
a gutter bottom, a ridge continuing to the gutter bottom, a vertical wall continuing to the ridge, and an outward continuous flange being continuously formed along at least one end in the predetermined direction, the one end at least including a part of the ridge, a part of the gutter bottom, and a part of the vertical wall, the method comprising: a first step in which
the pad presses the forming material against the punch to raise a portion corresponding to a flange to be formed in ends of at least the gutter bottom and the ridge in a direction opposite to the pressing direction, and
the punch and the die carry out press forming to form an intermediate product, while the pad bends an end of a portion to be formed into the ridge in the pressing direction and restrains at least a part of the end, and a region other than an end in a portion to be formed into the gutter bottom remains unrestrained; and
a second step in which
the intermediate product is further pressed to form the structural member for the automotive body.

2 . The method for manufacturing a structural member for an automotive body according to claim 1 , wherein at least a part of the end of the portion to be formed into the gutter bottom is unrestrained in the first step.

3 . The method for manufacturing a structural member for an automotive body according to claim 1 , wherein the whole portion to be formed into the gutter bottom and at least a part of the portion corresponding to the flange to be formed in the end of the gutter bottom, the part continuing to the portion to be formed into the gutter bottom, remain unrestrained in the first step.

4 . The method for manufacturing a structural member for an automotive body according to claim 1 , wherein a portion of at least ½ length of a perimeter of a cross section in the end of the portion to be formed into the ridge, the ½ length starting from a border between the portion to be formed into the ridge and the portion to be formed into the gutter bottom, remains unrestrained in the first step.

5 . The method for manufacturing a structural member for an automotive body according to claim 1 , wherein, the punch used in the first step has a shoulder having a surface for forming the ridge, and at least a portion of the shoulder corresponding to the end in the predetermined direction has a curvature radius ranging from 2 mm to 45 mm.

6 . The method for manufacturing a structural member for an automotive body according to claim 1 , wherein the steel sheet is a steel sheet of 2.3 mm or more in thickness or a high-tensile steel sheet of 440 MPa or more in tensile strength.

7 . A press-forming apparatus used for manufacturing a structural member for an automotive body, the structural member extending in a predetermined direction, having a substantially gutter-shaped cross section intersecting the predetermined direction, and including
a gutter bottom, a ridge continuing to the gutter bottom, a vertical wall continuing to the ridge, and an outward continuous flange being continuously formed along at least one end in the predetermined direction, the one end at least including a part of the ridge, a part of the gutter bottom, and a part of the vertical wall,
the press-forming apparatus comprising: a punch; a die; and a pad facing the punch, the punch and the die carrying out press forming while the pad and the punch restraining a forming material made of a steel sheet,
wherein the pad presses the forming material to bend an end of a portion to be formed into the ridge in the pressing direction, and restrains at least a part of the end while a region other than an end in a portion to be formed into the gutter bottom remains unrestrained.

8 . The press-forming apparatus according to claim 7 , wherein the pad leaves at least a part of the end of the portion to be formed into the gutter bottom unrestrained.

9 . The press-forming apparatus according to claim 7 , wherein the pad leaves unrestrained the whole portion to be formed into the gutter bottom and at least a part of the portion corresponding to the flange to be formed in the end of the gutter bottom, the part continuing to the portion to be formed into the gutter bottom.

10 . The press-forming apparatus according to claim 7 , wherein the pad leaves unrestrained a portion of at least ½ length of a perimeter of a cross section in the end of the portion to be formed into the ridge, the ½ length starting from a border between the portion to be formed into the ridge and the portion to be formed into the gutter bottom.

11 . The press-forming apparatus according to claim 7 , wherein the punch has a shoulder having a surface for forming the ridge, and at least a portion of the shoulder corresponding to the end in the predetermined direction has a curvature radius ranging from 2 mm to 45 mm.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Ito Yasuhiro
• Nishimura Ryuichi
• Otsuka Kenichiro
• Nakazawa Yoshiaki

Classifications

• B21D53/88

  other parts for vehicles, e.g. cowlings, mudguards · CPC title

• B21D5/16

  Folding; Pleating · CPC title

• B21D22/26 Primary

  for making peculiarly, e.g. irregularly, shaped articles · CPC title

• B21D24/16

  Additional equipment in association with the tools, e.g. for shearing, for trimming · CPC title

• B21D24/04

  Blank holders; Mounting means therefor · CPC title