Jfe Steel Corporation

Kabushiki Kaisha Toshiba

Kawasaki Steel Corporation

Masaki Urabe

Yusuke Vincent Fujii

Takeshi Fujita

Takeshi Ogawa

Yoshikiyo Tamai

Toru Minote

Satoshi Sumikawa

Jiro Hiramoto

Osamu Sonobe

Akinobu Ishiwatari

Eiji Iizuka

Yuichi Tokita

Shunsuke Tobita

Yoshio Yoshimura

Hirotaka Kano

Teruyuki Nakanishi

Yusuke Fujii

Kiyoshi Hatano

Hiroshi Arimitsu

Tsurakazu Honda

Fumiaki Tamashiro

Taira Nakamoto

A press forming method includes: press forming a press formed product including a top portion, a side wall portion continuous from the top portion through a punch shoulder portion, and a flange portion continuous from the side wall portion through a die shoulder portion, the press formed product including a curved portion that is concave and curved in a top view; and increasing a bending radius of the punch shoulder portion in the curved portion from a center of a curve toward an end side of the curve.

Press forming method and press formed product

A method and apparatus for identifying a portion that is a factor causing a discrepancy in springback amount between a press-formed product and a CAE analysis. The method includes a formed product driving stress distribution acquisition step of acquiring a driving stress distribution of a press-formed product, an analysis driving stress distribution acquisition step of acquiring a driving stress distribution of a springback analysis, a stress difference distribution setting step of setting a stress difference distribution, a stress difference springback amount acquisition step of acquiring a springback amount based on the stress difference distribution, a changed stress difference springback amount acquisition step of acquiring a springback amount by changing a value in a region of the stress difference distribution, and a springback amount discrepancy factor portion identification step of identifying a portion that is a factor causing a discrepancy in springback amount by comparing the acquired springback amounts.

Springback amount discrepancy factor portion identification method and apparatus

A method for identifying a necking limit strain of a metal sheet includes a step of measuring the distribution of strain in a tensile orthogonal direction in a tensile deformation process of a notch root for two or more types of sheet specimens having a notch geometry in a portion of a sheet edge; a step of obtaining a strain increment ratio of the notch root in the tensile deformation process and a strain gradient in the tensile orthogonal direction; a step of obtaining necking limit strain at which necking occurs in the notch root based on the strain increment ratio in the tensile deformation process; and a step of identifying the necking limit strain as a function of the strain gradient from the relation between the necking limit strain obtained for the two or more types of sheet specimens and the strain gradient at that time.

Method for identifying necking limit strain of metal sheet

A press forming method for controlling a shape change of a press formed part over time after the press formed part springs back at a moment of a release from a press-forming die includes: a press forming step of press forming a metal sheet into the press formed part by using the press-forming die; a die releasing step of releasing the press formed part, which is press-formed, from the press-forming die; and a post-release die holding step of holding the released press formed part in a forming bottom dead center shape for 30 minutes or more by using the press-forming die.

Press forming method and shape evaluation method for press formed part

An automotive-structural-part joint structure is formed by bending one metal sheet, includes a groove portion including a top portion and a pair of side wall portions, is provided at an end part of one automotive structural part in a longitudinal direction, and is configured to join the one automotive structural part to another automotive structural part in an intersecting direction. The automotive-structural-part joint structure includes: a pair of vertical rib portions configured to stand upward from both side ends of the top portion; and an outward-directed flange portion configured to extend outward from three side edges of the groove portion on an end part side where the other automotive structural part is joined, the flange portion being continuously formed along the three side edges.

Automotive-structural-part joint structure, automotive structural part, and automotive-structural-part manufacturing method

A method for identifying a variation factor portion of a springback amount, including: performing press forming analysis under first press forming conditions, and calculating a residual stress distribution in a press formed part; performing springback analysis on the press formed part, and calculating a first springback amount; performing press forming analysis under second press forming conditions, and calculating a residual stress distribution in the press formed part; replacing a value of residual stress in a partial area of the residual stress distribution; performing springback analysis on the press formed part for which the value of the residual stress has been replaced, and calculating a second springback amount; obtaining a difference between the second springback amount and the first springback amount; and identifying a portion in the press formed part that is a factor for variation in springback amount of the press formed part based on the obtained difference.

Method for identifying variation factor portion of springback amount

A method of press forming that forms a press-formed product into a target shape, the method including: forming a top portion; forming a side wall portion and a flange portion such that a side wall height of the side wall portion of the press-formed product becomes larger than a side wall height of the target shape, where the side wall height of the side wall portion is formed to be larger than the side wall height of the target shape by adding a value half or less of a radius of curvature of the ridge, in a longitudinal direction vertical cross section, of the target shape; and reforming a ridge between the side wall portion and the flange portion such that the side wall height of the side wall portion becomes the side wall height of the target shape.

Press forming method

A springback variation cause analysis method includes: calculating a first stress distribution in a press forming part; calculating a second stress distribution in the press forming part; calculating a difference between the second and the first stress distribution, and replacing and setting the first or the second stress distribution with the calculated stress difference distribution; calculating a first springback amount to be caused in the press forming part; changing a value of stress difference in a partial area of the press forming part in the stress difference distribution set for the press forming part; calculating a second springback amount; and analyzing a portion in the press forming part that is a cause of variation in springback amount in the press forming part due to scattering or variation in press forming conditions, based on the second springback amount and the first springback amount.

Springback variation cause analysis method

A press forming method according to the present invention includes: a first forming step of forming the press formed part by using the first press forming tool having a line length in the cross-sectional direction of the joining portion contacting with a flange portion subjected to stretch flange deformation or a flange portion subjected to shrink flange deformation is a line length Lin the cross-sectional direction that is shorter than a line length L, where the line length Lis a line length in a cross-sectional direction of the joining portion of the second press forming tool for making the product shape; and a second forming step of forming the press formed part in the product shape by crash forming by using the second press forming tool in which the line length in the cross-sectional direction of the joining portion is L

Press forming method and press forming tool

A method for manufacturing a press formed part, the method including specifying stretch flange limit strain in a metal sheet by using strain gradient in a radial direction and strain gradient in a sheet thickness direction. The strain gradient in the radial direction being directed from an end portion of the metal sheet at a time a press load is applied. The strain gradient in the sheet thickness direction being a direction of the metal sheet that intersects a loading direction. Additionally, the stretch flange limit strain satisfies the formula &#x3f5;=A[a&#xb7;&#x394;&#x3f5;/&#x394;r+b&#xb7;&#x394;&#x3f5;/&#x394;t]+c, where &#x3f5;represents the stretch flange limit strain in a tangential direction of the sheet edge, &#x394;&#x3f5;/&#x394;r represents the strain gradient in the radial direction, &#x394;&#x3f5;/&#x394;t represents the strain gradient in the sheet thickness direction, A, a, and b represent influence coefficients, and c represents the limit strain at a time the strain gradient is zero.

Method for specifying stretch flange limit strain and method for determining feasibility of press forming

A press forming method of press forming a formed part including a top portion having a concave outer edge with a part of the outer edge being concave inwards and a flange portion subjected to bending forming along the concave outer edge of the top portion includes: a first forming step of forming a preformed shape part including, in a part where the flange portion is formed in a blank material, a vertical wall portion that becomes a part of the flange portion and a mountain shaped portion that is bent outwards from the vertical wall portion and is convex towards the top portion; and a second forming step of forming the flange portion by performing bending forming on a part including the mountain shaped portion of the preformed shape part formed at the first forming step along a bending line that is a boundary from the vertical wall portion.

A press forming method presses and forms a formed part including: a top portion having a projecting outer edge, a part of the projecting outer edge projecting outward; and a flange portion that formed by bending along the projecting outer edge of the top portion. The press forming method includes: a first forming step of forming, at a region of a blank material in which the flange portion is to be formed, a preformed part including a vertical wall portion to be a part of the flange portion and a trough portion that is bent outward from the vertical wall portion and recessed on a side of the top portion; and a second forming step of forming the flange portion by bending a region including the trough portion of the preformed part formed in the first forming step.

In an inductive radio control system for a vehicle, data transmission between a vehicle which travels along a predetermined route and a ground operation control unit is performed by inductive radio means in such a manner that one of the loop antennas discretely arranged along the predetermined route is coupled to a corresponding transmitter/receiver in accordance with the traveling position of the vehicle. The number of transmitters/receivers is the same as the maximum number of operating vehicles.

Growing community of inventors

Tokyo, Japan

Masaki Urabe