Manufacturing method and manufacturing apparatus for press-formed article

Patent metadata

Field	Value
Publication number	US-11059085-B2
Application number	US-201716339496-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Oct 5, 2016
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

The manufacturing method includes a first step in which a pad holding state is established and a second step in which pad draw forming is performed after the first step is completed. In the pad holding state, (a) a part of a blank 15 to be formed into a top plate 21 is held between a pad 13 and a punch 11, and a part of the blank 15 to be formed into a flange 25 is held between a die 14 and a blank holder 12, (b) in a specific press directional cross section of a part of the blank 15 to be formed into a first part, the position of the contacting surface of the blank holder 12 that makes contact with the blank 15 in the direction of pressing is located toward the punch 11 in the direction of arrangement of the pad 13 and the punch 11, compared with the position of the contacting surface of the pad 13 that makes contact with the blank 15 in the direction of pressing, (c) a vertically-reversing cross-sectional angle is more than 0° and equal to or less than 80°, and (d) in a press directional cross section that is different from the specific press directional cross section, the position of the contacting surface of the pad 13 that makes contact with the blank 15 in the direction of the pressing is located toward the pad 13 in the direction of the arrangement, compared with the position of the contacting surface of the blank holder 12 that makes contact with the blank 15 in the direction of pressing.

First claim

The invention claimed is:

1. A method of manufacturing a press-formed article, the method using a punch and a blank holder and a pad and a die arranged to be opposed to the punch and the blank holder, and the press-formed article being manufactured by pressing a metal sheet having a tensile strength of 400 MPa or more, which is a steel sheet, an aluminum sheet or an aluminum alloy sheet, disposed between the punch and the blank holder and the pad and the die,
wherein the press-formed article extends in a first direction, has a shape defined by a top plate, a ridge connected to the top plate, a vertical wall connected to the ridge and a flange connected to the vertical wall in each of press directional cross sections that are along a direction of pressing and intersect the first direction, has at least one curved part that is curved in the first direction in one or both of top view in the direction of pressing and side view in a direction intersecting the direction of pressing, and has a first part including the curved part and a second part continuous to the first part, a minimum height of the vertical wall in the second part is equal to or more than a maximum height of the vertical wall in the first part,
the method comprises a first step in which a pad holding state is established and a second step in which pad draw forming is performed using the punch and the blank holder and the pad and the die after the first step is completed, and
in the pad holding state,
a part of the metal sheet to be formed into the top plate is held between the pad and the punch, and a part of the metal sheet to be formed into the flange is held between the die and the blank holder,
of the press directional cross sections, in a specific press directional cross section of a part of the metal sheet to be formed into the first part, a position of a contacting surface of the blank holder that makes contact with the metal sheet in the direction of pressing is located higher than a contacting surface of the pad when the punch and the blank holder are arranged below the blank and the pad and the die are arranged above the blank, or the contacting surface of the blank holder is located lower than the contacting surface of the pad when the punch and the blank holder are arranged above the blank and the pad and the die are arranged below the blank,
a vertically-reversing cross-sectional angle, which is an acute angle formed by a straight line that connects a center of a rounded end part of the contacting surface of the pad and a center of a rounded end part of the contacting surface of the blank holder and an extension of the contacting surface of the pad that makes contact with the metal sheet, is more than 0° and equal to or less than 80°, and
of the press directional cross sections, in a press directional cross section that is different from the specific press directional cross section, the position of the contacting surface of the pad that makes contact with the metal sheet in the direction of the pressing is located higher than the contacting surface of the blank holder when the punch and the blank holder are arranged below the blank and the pad and the die are arranged above the blank or the contacting surface of the pad is located lower than the contacting surface of the blank holder when the punch and the blank holder are arranged above the blank and the pad and the die are arranged below the blank.

2. The method of manufacturing a press-formed article according to claim 1 , wherein in the first step, in the specific press directional cross section, the blank holder is placed at a height equal to or higher than a minimum height of the vertical wall, and the die is the first to start forming the metal sheet.

3. The method of manufacturing a press-formed article according to claim 1 , wherein in a cross section in the direction of pressing of at least a part in the first direction, the pad is the first to start forming the metal sheet.

4. The method of manufacturing a press-formed article according to claim 1 , wherein the metal sheet is an intermediate worked article formed from a starting metal sheet by a preforming.

5. A method of manufacturing a press-formed article, wherein a post-forming is performed on a press-formed article manufactured in the manufacturing method according to claim 1 .

6. An apparatus for manufacturing a press-formed article, the apparatus comprising a punch and a blank holder and a pad and a die arranged to be opposed to the punch and the blank holder, and the press-formed article being manufactured by pressing a metal sheet having a tensile strength of 400 MPa or more, which is a steel sheet, an aluminum sheet or an aluminum alloy sheet, disposed between the punch and the blank holder and the pad and the die,
wherein the press-formed article extends in a first direction, has a shape defined by a top plate, a ridge connected to the top plate, a vertical wall connected to the ridge and a flange connected to the vertical wall in each of press directional cross sections that are along a direction of pressing and intersect the first direction, has at least one curved part that is curved in the first direction in one or both of top view in the direction of pressing and side view in a direction intersecting the direction of pressing, and has a first part including the curved part and a second part continuous to the first part, a minimum height of the vertical wall in the second part is equal to or more than a maximum height of the vertical wall in the first part,
the apparatus configured to manufacture the press-formed article in a first step in which a pad holding state is established and a second step in which pad draw forming is performed using the punch and the blank holder and the pad and the die after the first step is completed, and
in the pad holding state,
a part of the metal sheet to be formed into the top plate is held between the pad and the punch, and a part of the metal sheet to be formed into the flange is held between the die and the blank holder,
of the press directional cross sections, in a specific press directional cross section of a part of the metal sheet to be formed into the first part, a position of a contacting surface of the blank holder that makes contact with the metal sheet in the direction of pressing is located higher than a contacting surface of the pad when the punch and the blank holder are arranged below the blank and the pad and the die are arranged above the blank, or the contacting surface of the blank holder is located lower than the contacting surface of the pad when the punch and the blank holder are arranged above the blank and the pad and the die are arranged below the blank,
a vertically-reversing cross-sectional angle, which is an acute angle formed by a straight line that connects a center of a rounded end part of the contacting surface of the pad and a center of a rounded end part of the contacting surface of the blank holder and an extension of the contacting surface of the pad that makes contact with the metal sheet, is more than 0° and equal to or less than 80°, and
of the press directional cross sections, in a press directional cross section that is different from the specific press directional cross section, the position of the contacting surface of the pad that makes contact with the metal sheet in the direction of the pressing is located higher than the contacting surface of the blank holder when the punch and the blank holder are arranged below the blank and the pad and the die are arranged above the blank or the contacting surface of the pad is located lower than the contacting surface of the blank holder when the punch and the blank holder are arranged above the blank and the pad and the die are arranged below the blank.

Assignees

• Nippon Steel Corp

Inventors

• Miyagi Takashi
• Tanaka Yasuharu
• Ogawa Misao
• Aso Toshimitsu
• Yamamoto Takashi

Classifications

• B21D22/26 Primary

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

• B21D53/88

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

• B21D24/10

  Devices controlling or operating blank holders independently, or in conjunction with dies · CPC title

• B21D22/24

  involving two drawing operations having effects in opposite directions with respect to the blank · CPC title

• B21D5/01 Primary

  between rams and anvils or abutments · CPC title