Jfe Steel Corporation

Kazuhiko Higai

Yusuke Vincent Fujii

Takeshi Fujita

Yuji Yamasaki

Yoshikiyo Tamai

Toyohisa Shinmiya

Tsuyoshi Shiozaki

Takaaki Hira

Katsuhiro Ochi

Takanobu Saito

Naoki Mabuchi

Shigeaki Kitamura

Koichi Nakagawa

Masayasu Nagoshi

Takahiro Kubota

Katsuya Hoshino

Takayuki Futatsuka

Hideo Kijima

Wataru Tanimoto

Masahiko Tada

Yusuke Fujii

An automotive crashworthiness energy absorptive part absorbs crashworthiness energy by crushing axially when a crashworthiness load is input from a front side or a rear side of an automotive body, and includes: a tubular member formed of a steel sheet with a tensile strength of 590 MPa to 1180 MPa, the tubular member including a top portion and a pair of side wall portions continuous from both ends of the top portion via corner portions; a closed cross section space forming wall member formed of a steel sheet with a tensile strength lower than the tubular member, the closed cross section space forming wall member being disposed on an inner surface side of the tubular member and forming a closed cross section space between the closed cross section space forming wall member and at least the corner portion; and a resin provided in the closed cross section space.

Automotive crashworthiness energy absorptive part

An automotive crashworthiness energy absorption part provided at a front part or a rear part of an automotive body and absorbing crashworthiness energy by undergoing axial crush when receiving input of a crashworthiness load from a front or a rear of the automotive body includes: a tubular member configured to absorb crashworthiness energy by undergoing axial crush, the tubular member including a top portion and side wall portions continuous with the top portion; and resin coated or patched on first outer surfaces including at least outer surfaces of the top portion and the side wall portions of the tubular member. The coated or patched resin has a thickness of 8 mm or less after being heated, forms at least part of a peripheral wall portion of a closed cross section space, and is bonded to the first outer surfaces with an adhesive strength of 10 MPa or more.

Automotive crashworthiness energy absorption part and method for manufacturing the same

An automotive crashworthiness energy absorptive part to be provided at a front portion or a rear portion of an automotive body, the automotive crashworthiness energy absorptive part including: a tubular member configured to be axially crushed to absorb crashworthiness energy, the tubular member having a top portion and side wall portions continuous to the top portion; and a resin configured to coat or patch at least inner surfaces of the top portion and the side wall portions of the tubular member, wherein the coated or patched resin has a thickness of 8 mm or less after being heated and forms at least a part of a peripheral wall portion in a closed cross-sectional space, and adheres to the inner surfaces with an adhesive strength of 10 MPa or more.

Automotive crashworthiness energy absorptive part and method for manufacturing same

An automotive frame part is provided to a side portion of an automotive body and absorbs crashworthiness energy by bending upon receiving a crashworthiness load from a side of the automotive body. The automotive frame part includes: a member having a hat-shaped cross section or a U-shaped cross section and including a top portion, and a pair of side wall portions that are continuous from the top portion via punch shoulder R portions; and resin that is coated on or patched to an internal surface of the member having the hat-shaped cross section member or the U-shaped cross section. The resin extends at least to a predetermined range toward the top portion and the side wall portions on both sides of the punch shoulder R portions, and is adhered, after heating, to the internal surface at an adhesive strength of 10 MPa or higher at a room temperature.

Automotive frame part

A crashworthiness energy absorption part includes: a tubular member having tensile strength of 590 to 1180 MPa grade; a closed cross section space forming wall part having tensile strength lower than the tubular member and having both edge portions joined to inner surfaces of a pair of side wall portions of the tubular member, and forming a closed cross section space between the closed cross section space forming wall part and a part of a peripheral wall portion of the tubular member; and a resin configured to fill the closed cross section space, includes a rubber-modified epoxy resin and a curing agent, and has tensile breaking elongation of 80% or more, adhesive strength to the tubular member and closed cross section space forming wall part of 12 MPa or higher, and a compression nominal stress of 6 MPa or higher at a compression nominal strain of 10%.

Crashworthiness energy absorption parts for automotive

An automotive frame part that is an A-pillar-lower part, the A-pillar-lower part including: an outer panel having approximately a T-shape in planar view and a cross section intersecting a portion corresponding to a horizontal side and a vertical side of the T-shape is a hat-shaped cross section including a top portion, a side wall portion, and a flange portion; an inner panel being connected to the flange portion and forming a closed cross section with the outer panel; and plastic stiffening members that each have one end connected to an inner surface of the outer panel and another end connected to an inner surface of the inner panel, wherein the shape and the disposition of the stiffening members are set based on an analysis result from a shape optimization analysis method and each of the stiffening members has a columnar shape or a columnar shape with both end parts bulging.

A stiffening structure for an automotive door panel part according to the present invention includes a door outer panelmade of a metal sheet curved along a height direction, and in which a character lineis formed; and an impact beamdisposed at an inner surface side of the door outer panel. The stiffening structure improves tensile rigidity of the door outer panelby attaching a stiffening membermade of resin to the inner surface of the door outer panel. The stiffening memberincludes vertical bone portionsextending in a streak shape from the impact beamto the character linealong a curve of the door outer panel. The vertical bone portionsare arranged at a predetermined interval in a front-rear direction of the door outer panel, and outer surface of the vertical bone portionsis bonded to the inner surface of the door outer panel

Stiffening structure and stiffening method for automotive door panel part

An apparatus that manufactures a closed-structure part includes a bottom portion and left and right side wall portions, including a press-forming die that form a plurality of first out-of-plane deformed portions and bent portions, the first out-of-plane deformed portions being formed in a region of a workpiece corresponding to the bottom portion and arranged along a longitudinal direction, each of the first out-of-plane deformed portions having a recessed shape or a protruding shape; a pad and a punch that squash the first out-of-plane deformed portions by clamping the region of the workpiece corresponding to the bottom portion therebetween, a cross-sectional shape of a pressing portion of the punch being curved along the longitudinal direction; and bending dies that bend the bent portions by pressing the punch into a space therebetween while the region of the workpiece corresponding to the bottom portion is clamped between the pad and the punch.

Apparatus that manufactures closed-structure part

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.

Method of forming a closed cross-sectional structure

A method manufactures a closed-structure part by forming a flat plate-shaped workpiece into a closed structure including a bottom portion curved along a longitudinal direction. The method includes a first forming step of forming a plurality of first out-of-plane deformed portions and a bent portion, the first out-of-plane deformed portions being formed in a region of the workpiece corresponding to the bottom portion and arranged along the longitudinal direction, each of the out-of-plane deformed portions having a recessed shape or a protruding shape; and a second forming step of squashing the first out-of-plane deformed portions between a pad and a punch such that the region of the workpiece corresponding to the bottom portion is curved and bending bent portions by pressing the punch into a space between dies while the region of the workpiece corresponding to the bottom portion is clamped between the pad and the punch.

Method of manufacturing closed-structure part and apparatus for the same

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.

Method and apparatus that forms a closed cross-sectional structure

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.

Method of manufacturing curvilineal closed structure parts without flange and apparatus for the same

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.

A prediction equation 'R/t&#x2267;(2R/t+(2R/t+1)&#x3b5;)/2(1&#x2212;(1+2R/t)&#x3b5;)' is derived which predicts that bendability-dominated fracture will not occur when the critical surface strain &#x3b5;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 Rof a press-forming mold and the critical strain &#x3b5;in a plane strain region in a forming limit diagram. The minimum curvature radius Rof 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 R.

Press-forming mold designing method and press-forming mold

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. In the O-shape forming die set, a die mating line is inclined downwardly, and a ratio t/D of a sheet thickness t of the blank to a diameter D, which represents a diameter of a portion of the O-shape forming die set corresponding to the small diameter portion and a diameter of a portion of the O-shape forming die set corresponding to the large diameter portion, is 0.010&#x2266;t/D&#x2266;0.080.

Growing community of inventors

Tokyo, Japan

Kazuhiko Higai