Method for manufacturing press formed article and press forming device

A method for manufacturing a press formed article from a metal sheet, the press formed article including a top sheet portion, a vertical wall portion continuous to end portions in a width direction of the top sheet portion via a protruding ridge portion, and an outward flange portion continuous to longitudinal end portions of the top sheet portion, longitudinal end portions of the protruding ridge portion, and longitudinal end portions of the vertical wall portion via a recessed ridge portion, the method comprising:

• bending the metal sheet at a position where the protruding ridge portion is to be formed and forming the metal sheet into an L-shape in cross section in order to form the top sheet portion, the vertical wall portion and the protruding ridge portion;
• and
• bending the metal sheet at a position where the recessed ridge portion is to be formed and forming the outward flange portion and the recessed ridge portion, wherein:
• in the bending of the metal sheet at the position where the recessed ridge portion is to be formed and forming the outward flange portion:
• starting an application of a bending force to an area of the metal sheet continuous to the longitudinal end portions of the top sheet portion and to an area continuous to the longitudinal end portions of the vertical wall portion, and
• applying the bending force to the area of the metal sheet continuous to the longitudinal end portions of the protruding ridge portion only after starting the application of the bending force to the area of the metal sheet continuous to the longitudinal end portions of the top sheet portion and to the area continuous to the longitudinal end portions of the vertical wall portion;
• and
• after completion of the forming of the L-shape in cross section, completing the forming of the area of the metal sheet continuous to the longitudinal end portion of the protruding ridge portion.

A press forming device for manufacturing, from a metal sheet, a press formed article including a top sheet portion, a vertical wall portion continuous to end portions in a width direction of the top sheet portion via a protruding ridge portion, and an outward flange portion continuous to longitudinal end portions of the top sheet portion, longitudinal end portions of the protruding ridge portion, and longitudinal end portions of the vertical wall portion via a recessed ridge portion, the press forming device comprising:

• a first upper die and a first lower die having forming surfaces that are configured to form areas to be the top sheet portion and the vertical wall portion at a position where the protruding ridge portion is to be formed and configured to form the top sheet portion and the vertical wall portion continuous to the top sheet portion;
• and
• a second lower die that is configured to bend the metal sheet at a position where the recessed ridge portion is to be formed and configured to form the outward flange portion, wherein
• the second lower die is configured to include, when viewed from a longitudinal direction of the top sheet portion, a top portion and a pair of slant surfaces continuous to both right and left sides of the top portion in order to form one continuous surface and have a protruding shape configured to protrude in a bending direction of the outward flange portion to be formed as a whole,
• an entire portion of the top portion is rounded;
• and
• the top portion of the protruding shape is configured to be able to abut on an area of the metal sheet continuous to the longitudinal end portions of the top sheet portion in order to form the outward flange portion.