Abstract: A method of forming a closed cross-sectional structure press-forming the plate-shaped workpiece into portions corresponding to bottom portion and left and right side wall portions; and providing bend-facilitating lines at the plurality of bend lines; bending the workpiece in a direction that the portions corresponding to the left and right side wall portions approach each other by pressing a punch into a space between a pair of dies while clamping the portion corresponding to the bottom portion between the punch and a pad in a plate thickness direction; and bending the corresponding portions along the bend-facilitating lines by pressing the corresponding portions against an outer periphery of a plug having an outer peripheral shape the same as a final shape of the closed cross-sectional structure while the plug is placed on the portion of the workpiece corresponding to the bottom portion.

Abstract: A method and die set for manufacturing a metal component with a three-dimensional edge from a blank as a raw material. The blank is cut from a metal sheet and has a curve-shaped curved edge portion with two ends. The method includes providing a bend formation line and forming the three-dimensional shape using a first die and a second die.

Abstract: A method and die set for manufacturing a metal component with a three-dimensional edge from a blank as a raw material. The blank is cut from a metal sheet and has a curve-shaped curved edge portion with two ends. The method includes providing a bend formation line and forming the three-dimensional shape using a first die and a second die.

Abstract: There is provided a method of manufacturing a curved channel part having a curved portion in a vertical wall portion by press forming, the method restricting stretch flange deformation, which occurs in the vertical wall portion and a flange portion. The method includes a shear deformation step as a step of forming the vertical wall portion. In the shear deformation step, a boundary-side portion of a base section of a blank with respect to a deformation section, and an outer portion of the deformation section are individually restrained, a portion to be a vertical wall portion of the deformation section is shear-deformed in a sheet face, and a material is caused to flow from a portion separated from a curved portion toward the curved portion in an outer edge portion of the portion to be the vertical wall portion.

Abstract: A method of producing a polygonal closed cross-section structural component includes press-forming a metal sheet into a gutter-shaped pre-processed part with a curved form along its longitudinal direction having plural ridge lines corresponding to corner portions of the polygonal closed cross-section in a cross-sectional form developed by cutting the component at a position corresponding to the ridge line located at the innermost side in the radial direction to provide a flange portion extending along the ridge line at the resulting respective ends, and press-forming the pre-processed part to deform inwardly in the cross-sectional direction at a position of one or more of the plural ridge lines to butt the ridge lines located at the innermost side and the flange portions to each other.

Abstract: A press-forming method for a component having a hat-shaped or U-shaped cross section and comprising a curved portion curved in a widthwise direction along with a longitudinal direction and straight side portions connecting to both ends of the curved portion from a sheet-shaped blank, wherein the blank is drawn to a hat-shaped or U-shaped cross section through a hat-shaped cross-sectional form having a top portion, vertical wall portions connecting at their upper end parts to both end parts of the top portion through fillet portions, and flange portions connecting at their internal end parts to the lower end parts of the vertical wall portions through fillet portions, and a material movement in the flange portion of the curved portion is caused in the drawing to mitigate tensile deformation or compression deformation in the circumferential direction generated in the flange portion of the curved portion.

Abstract: A method of forming a closed cross-sectional structure press-forming the plate-shaped workpiece into portions corresponding to bottom portion and left and right side wall portions; and providing bend-facilitating lines at the plurality of bend lines; bending the workpiece in a direction that the portions corresponding to the left and right side wall portions approach each other by pressing a punch into a space between a pair of dies while clamping the portion corresponding to the bottom portion between the punch and a pad in a plate thickness direction; and bending the corresponding portions along the bend-facilitating lines by pressing the corresponding portions against an outer periphery of a plug having an outer peripheral shape the same as a final shape of the closed cross-sectional structure while the plug is placed on the portion of the workpiece corresponding to the bottom portion.

Abstract: A method of sheet forming manufactures a sheet-formed part that is formed in an L-shape as viewed in a plan view and includes a top portion, side wall portions formed on the respective both sides of the top portion, and flange portions contiguously formed with the respective side wall portions, by sheet-forming a metal sheet with the a sheet forming tool. The method includes: a first sheet forming process in which the metal sheet is arranged on a first sheet forming tool including a first punch, a first die, a first blank holder, and a pad; and a second sheet forming process in which the first sheet-formed part formed is sheet-formed into a second sheet-formed part having a top portion and a side wall portion whose shapes are identical with those of the sheet-formed part, with a second sheet forming tool having a second punch and a second die.

Abstract: A workpiece is formed into a shape having curvatures in the longitudinal and width directions required for a final closed cross-sectional shape, and bend-facilitating lines are provided at positions corresponding to bent lines in the closed cross-sectional shape. The workpiece formed in the first step is bent in a direction that left and right side wall portions approach each other by clamping the bottom portions between a punch and pad in the plate thickness direction and by pressing a punch into a space between dies. A plug having an outer shape the same as the final closed cross-sectional shape is placed on the bottom portion of the workpiece formed in the second step, and the bottom portion and the left and right side wall portions are bent along the bend-facilitating lines by pressing the bottom portion and the left and right side wall portions against a periphery of the plug.

Abstract: There is provided a press forming method capable of suppressing a camber back, which occurs in a hat-shaped member while reducing a restriction on a shape of the hat-shaped member. At a time of the press forming, a blank material (4) in which a longitudinal line length is at least longer than a longitudinal line length of a top plate portion of a hat-shaped member (5) is fixed between a pair of press dies (lower die (2), upper die (3)), which have bent surfaces (convex surface (2a), concave surface (3a)), while being warped upward, that is, in a bending direction of the lower die (2) and the upper die (3). Subsequently, for the fixed blank material (4), a bent portion of the hat-shaped member (5) is press formed by using the convex surface (2a) and the concave surface (3a).

Abstract: A method and apparatus manufactures a closed structure part without flange having a curvature and welded edges along a longitudinal direction of the part and further having a varying cross-sectional shape, from two metal plates. Each of two metal plates provided with a curvature along the longitudinal direction of the plate and provided with both ends in a width direction of the plate, are press-formed such that a folding line is formed at positions corresponding to a non-welded bent edge in a cross section of the part, and stacked on each other vertically such that their bulging sides face outward. Their left ends and right ends in the width direction are mutually welded along the longitudinal direction to form welded edges.

Abstract: A workpiece is formed into a curved shape that has curvatures in the longitudinal and width directions required for a final closed cross-sectional shape. The formed workpiece is bent in a direction that left and right side wall portions approach each other by clamping the bottom portions between a punch and pad in a plate-thickness direction. A pair of flange portions are butted against each other while the formed bottom portions of the workpiece are placed on a pad; and a die cavity having the same shape as the final closed cross-sectional shape is defined between a support surface of the pad supporting the bottom portion and pressing surfaces of a pair of pressure cams pressing the left and right side wall portions. Then, the pair of flange portions are depressed toward the cavity using depressing portions of a second punch disposed above the pair of flange portions.

Abstract: A press forming method forms a metal plate into the part shape having at least a top surface portion and side wall portions continuous with both left and right sides of the top surface portion, the part shape having a U-shaped or hat-shaped cross section and having one or two or more bent portions bent in a longitudinal direction that is a direction intersecting the cross section. The press forming method includes: a first step of applying in-plane shear deformation to a plate portion on both sides or one side of the bent portions in the longitudinal direction of the metal plate, the in-plane shear deformation corresponding to a direction of bending the portion of the part shape; and a second step of implementing press forming for the metal plate into the part shape, the metal plate to which the in-plane shear deformation has been applied.

Abstract: A press forming method includes portions of a blank corresponding to straight portions of product is press formed to a hat or channel cross-sectional shape prior to a portion of the blank corresponding to a curved portion of the product at an approached state of the both ends to thereby leave a surplus in a length of the portion of the blank corresponding to the curved portion of the product as compared to a length of the curved portion; then the portion of the blank corresponding to the curved portion of the product is press formed to a longitudinal curved shape at a state of leaving the surplus while forming the hat or channel cross-sectional shape to thereby apply a longitudinal compression stress to the portion of the blank corresponding to curved portion of the product.

Abstract: A method is provided for press forming a product having a shape of a top board portion, a vertical wall portion continuously formed from the top board portion and a flange portion continuously formed from the vertical wall portion at a press process of two or more stages, wherein a convex or concave bead shape is preformed in a position of a flat metal sheet as a raw material corresponding to a neighborhood of a position generating breakage or flange wrinkles when the raw material is formed into a product shape, and thereafter a product shape is press formed from the raw material having the preformed bead shape.

Abstract: A method of sheet forming manufactures a sheet-formed part that is formed in an L-shape as viewed in a plan view and includes a top portion, side wall portions formed on the respective both sides of the top portion, and flange portions contiguously formed with the respective side wall portions, by sheet-forming a metal sheet with the a sheet forming tool. The method includes: a first sheet forming process in which the metal sheet is arranged on a first sheet forming tool including a first punch, a first die, a first blank holder, and a pad; and a second sheet forming process in which the first sheet-formed part formed is sheet-formed into a second sheet-formed part having a top portion and a side wall portion whose shapes are identical with those of the sheet-formed part, with a second sheet forming tool having a second punch and a second die.

Abstract: A method of producing a polygonal closed cross-section structural component includes press-forming a metal sheet into a gutter-shaped pre-processed part with a curved form along its longitudinal direction having plural ridge lines corresponding to corner portions of the polygonal closed cross-section in a cross-sectional form developed by cutting the component at a position corresponding to the ridge line located at the innermost side in the radial direction to provide a flange portion extending along the ridge line at the resulting respective ends, and press-forming the pre-processed part to deform inwardly in the cross-sectional direction at a position of one or more of the plural ridge lines to butt the ridge lines located at the innermost side and the flange portions to each other.

Abstract: There is provided a method of manufacturing a curved channel part having a curved portion in a vertical wall portion by press forming, the method restricting stretch flange deformation, which occurs in the vertical wall portion and a flange portion. The method includes a shear deformation step as a step of forming the vertical wall portion. In the shear deformation step, a boundary-side portion of a base section of a blank with respect to a deformation section, and an outer portion of the deformation section are individually restrained, a portion to be a vertical wall portion of the deformation section is shear-deformed in a sheet face, and a material is caused to flow from a portion separated from a curved portion toward the curved portion in an outer edge portion of the portion to be the vertical wall portion.

Abstract: A prediction equation “R0/t?(2R/t+(2R/t+1)?f)/2(1?(1+2R/t)?f)” is derived which predicts that bendability-dominated fracture will not occur when the critical surface strain ?critical is not exceeded by a strain on the metal sheet surface causing the occurrence of ductility-dominated fracture that is obtained from the minimum curvature radius R0 of a press-forming mold and the critical strain ?f in a plane strain region in a forming limit diagram. The minimum curvature radius R0 of a mold required to prevent the occurrence of bendability-dominated fracture is estimated, and the mold is designed with a curvature radius that is not less than the curvature radius R0.

Abstract: A method of manufacturing a pipe with different diameters along a longitudinal direction that has a small diameter portion, a large diameter portion, and a diameter-changing portion provided between the small diameter portion and the large diameter portion and is formed by press forming a blank made of a metal sheet includes press forming the blank with a U-shape forming die into a U-shaped formed part and press forming the U-shaped formed part with an O-shape forming die set into a circular cross-section formed part. A length of a vertical wall of the U-shape forming die is longer than a length of a vertical wall portion of the U-shaped formed part.