Abstract: A roll forming apparatus for roll forming for producing from a sheet material a shaped steel which varies in cross-sectional shape in a longitudinal direction comprises a first rolling die which has an annular ridge part which varies in cross-sectional shape in a circumferential direction; a second rolling die which has an annular groove part which varies in cross-sectional shape in a circumferential direction; and a drive device for the first rolling die and the second rolling die. At least transition parts of the side surfaces of the annular ridge part of the first rolling die are provided with relief so that the gap with respect to the side surfaces of the annular groove part of the second rolling die becomes broader inward in the radial direction.

Abstract: A metal pipe having a thickened end portion, the metal pipe includes: when viewed in a longitudinal direction of the metal pipe, a thin portion which has a thickness t0; a first thickened portion which is provided on one end and has a thickness T which is larger than the thickness t0; and a first taper portion which is provided between the thin portion and the first thickened portion and has the thickness which gradually increases from t0 to T; when a hardness of an inner surface of the first thickened portion is measured in a circumferential direction and the hardness is plotted with respect to a position in the circumferential direction, in which a waveform representing a high hardness portion having a hardness which is 95% or more of a maximum hardness in the circumferential direction and a waveform representing a low hardness portion having a hardness which is less than 95% of the maximum hardness alternately appear, and a plurality of combinations of the waveform representing the high hardness portion an

Abstract: A method of manufacturing a flaring-processed metal pipe from a hollow shell including a plurality of portions having different deformation resistances in a circumferential direction is provided, the method includes: among the plurality of portions, specifying a portion having a relatively small deformation resistance as a low deformation resistance section, and a portion having a relatively large deformation resistance as a high deformation resistance section; and press-fitting a pipe expansion punch into the hollow shell such that a thickness reduction rate of the low deformation resistance section is smaller than a thickness reduction rate of the high deformation resistance section.

Abstract: The present invention provides a new bending apparatus and bending method of a tube material which makes it possible to achieve all of bending by a large bending radius not requiring large scale equipment or die, bending resistant to wrinkling and buckling at an inner side of the bending, and bending with a high productivity, that is, a ram bending apparatus using a punch 12 and a set of rolls 13, 13 for three-point bending of a tube material wherein the punch 12 has a groove 12a of a width of the width of a circular tube 11 or more and wherein the set of rolls 13, 13 are supported by a frame 14. The rolls 13, 13 can freely move on the frame 14 in directions away from each other in a state contacting the punch 12. The frame 14 has a hollow space 14a enabling free movement of the descending punch 12 and the circular tube 11 bent along with this during the bending of the circular tube 11.

Abstract: A method for bending a sheet metal comprises: a hardness adjustment process wherein a blank (10), including a high-hardness region (11) and a low-hardness region (12) having a lower hardness than the high hardness region (11), is formed by changing the hardness of at least a part of a sheet metal; and a bending process wherein a product (20) is formed by bending low-hardness region (12) of blank (10).

Abstract: In the present invention, in a piercing punch and a burring punch which are shaft members having a first axis line as the center axis lines and are provided so as to be movable along the first axis line, first, after prepared holes having the first axis line as the center axis lines with respect to the first wall portion and the second wall portion are formed using the piercing punch, burring holes having the first axis line as the center axis lines with respect to the first wall portion and the second wall portion are formed using the burring punch.

Abstract: The present invention provides a new bending apparatus and bending method of a tube material which makes it possible to achieve all of bending by a large bending radius not requiring large scale equipment or die, bending resistant to wrinkling and buckling at an inner side of the bending, and bending with a high productivity, that is, a ram bending apparatus using a punch 12 and a set of rolls 13, 13 for three-point bending of a tube material wherein the punch 12 has a groove 12a of a width of the width of a circular tube 11 or more and wherein the set of rolls 13, 13 are supported by a frame 14. The rolls 13, 13 can freely move on the frame 14 in directions away from each other in a state contacting the punch 12. The frame 14 has a hollow space 14a enabling free movement of the descending punch 12 and the circular tube 11 bent along with this during the bending of the circular tube 11.

Abstract: A roll forming device, for roll forming for the purpose of manufacturing shaped steel the cross-sectional shape of which varies in the longitudinal direction, is equipped with: first die rolls having an annular ridge part the cross-sectional shape of which varies in the circumferential direction; second die rolls having an annular groove part the cross-sectional shape of which varies in the circumferential direction; and a drive device for the first die rolls and the second die rolls. A gap is provided at the side surfaces of the annular ridge part of the first die rolls, across the entire circumference in the circumferential direction, such that the gap with respect to the side surfaces of the annual groove parts of the second die rolls widens inward in the radial direction.

Abstract: A roll forming apparatus for roll forming for producing from a sheet material a shaped steel which varies in cross-sectional shape in a longitudinal direction comprises a first rolling die which has an annular ridge part which varies in cross-sectional shape in a circumferential direction; a second rolling die which has an annular groove part which varies in cross-sectional shape in a circumferential direction; and a drive device for the first rolling die and the second rolling die. At least transition parts of the side surfaces of the annular ridge part of the first rolling die are provided with relief so that the gap with respect to the side surfaces of the annular groove part of the second rolling die becomes broader inward in the radial direction.

Abstract: A structural hydroformed joint member has projecting portions (30a, 30b) formed integrally on an outer peripheral face of a hollow main tube part (20) by hydroforming an element tube with an outside diameter D. In this case, both intersecting planes (35a, 35b), which are projecting planes of end faces (33a, 33b) of the projecting portions (30a, 30b) toward the main tube part (20), share a plane perpendicular to the main axis (40) of the main tube part (20) only in portions (36a, 36b) of the intersecting planes (35a, 35b). At that time, by setting areas of the portions (36a, 36b) to 30% or more and 90% or less relative to an area of each of the intersecting planes (35a, 35b), a projecting height of each of the projecting portions (30a, 30b) is 0.3D or higher for functioning as a joint.

Abstract: A camshaft-manufacturing method includes: a split die group preparation step; a processing preparation step of preparing a cam including a through-hole, a cam body which is smaller than each of the cam accommodation portions, and ribs which are provided on both sides in a thickness direction of the cam body and configured to be fitted into the rib accommodation portions, and a hollow shaft, accommodating the cam body in the cam accommodation portion and fitting the ribs in the rib accommodation portion, and inserting the hollow shaft into the through-hole of the cam; and a processing step of performing hydroform processing, and fixing the cam to the hollow shaft by expanding the hollow shaft.

Abstract: A roll forming device, for roll forming for the purpose of manufacturing shaped steel the cross-sectional shape of which varies in the longitudinal direction, is equipped with: first die rolls having an annular ridge part the cross-sectional shape of which varies in the circumferential direction; second die rolls having an annular groove part the cross-sectional shape of which varies in the circumferential direction; and a drive device for the first die rolls and the second die rolls. A gap is provided at the side surfaces of the annular ridge part of the first die rolls, across the entire circumference in the circumferential direction, such that the gap with respect to the side surfaces of the annual groove parts of the second die rolls widens inward in the radial direction.

Abstract: Provided is a plastic working method of steel including austenite, the method including: analyzing a strain ratio ?x of an estimated breaking point which is specified during plastic deformation of the steel; heating a steel such that a local temperature Tlocal is within a temperature range indicated by the following expression 1, when T?x represents a strain-induced-transformation-maximum-ductility-temperature in the unit of ° C. for the strain ratio ?x, ?L?x represents the standard deviation of a fitted curve of critical equivalent strain which depends on the strain ratio ?x on a lower temperature side than T?x, ?H?x represents the standard deviation of a fitted curve of critical equivalent strain which depends on the strain ratio ?x on a higher temperature side than T?x, and Tlocal represents a local temperature in the unit of ° C. of the estimated breaking point; and plastically deforming the steel after heating: T?x?2×?L?x?Tlocal?T?x+1.25×?H?x??(Expression 1).

Abstract: A coupling structure includes a hollow rod section formed of a metal pipe and fastening sections formed by plastic deformation of the metal pipe so as to be connected with end sections of the hollow rod section. The fastening section includes a pair of base end sections which are each connected with a peripheral wall section forming a closed cross-section at the end section of the hollow rod section, and are separated from each other, and a bottom wall including a flat surface connected with the pair of the base end sections, and a pair of front end sections including a pair of side walls curving inwards from at least widthwise end sections of the bottom wall on a base end section side.

Abstract: A structure (10) for a front section of a vehicle body in a vehicle body (1) comprising a front chamber (3) disposed on the forward side of a vehicle interior (2) is provided with the following: a pair of front side members (11), located within the front chamber, that extend in the longitudinal direction of the vehicle body; a pair of strut towers (16) disposed on either side in the width direction of the front chamber and within which front wheel suspensions are disposed; and reinforcement members (20) that link the top of each strut tower with the front side members that face the strut towers, and that extend between the strut towers and the front side members. This configuration allows a structure for a front section of a vehicle body to be provided that can efficiently improve the rigidity of the vehicle body of an automobile against torsion and against lateral bending, and that can efficiently reduce the weight of the vehicle body by means of thickness reduction using a high-strength steel plate.

Abstract: A structural hydroformed joint member has projecting portions (30a, 30b) formed integrally on an outer peripheral face of a hollow main tube part (20) by hydroforming an element tube with an outside diameter D. In this case, both intersecting planes (35a, 35b), which are projecting planes of end faces (33a, 33b) of the projecting portions (30a, 30b) toward the main tube part (20), share a plane perpendicular to the main axis (40) of the main tube part (20) only in portions (36a, 36b) of the intersecting planes (35a, 35b). At that time, by setting areas of the portions (36a, 36b) to 30% or more and 90% or less relative to an area of each of the intersecting planes (35a, 35b), a projecting height of each of the projecting portions (30a, 30b) is 0.3D or higher for functioning as a joint.

Abstract: A structural hydroformed joint member has projecting portions (30a, 30b) formed integrally on an outer peripheral face of a hollow main tube part (20) by hydroforming an element tube with an outside diameter D. In this case, both intersecting planes (35a, 35b), which are projecting planes of end faces (33a, 33b) of the projecting portions (30a, 30b) toward the main tube part (20), share a plane perpendicular to the main axis (40) of the main tube part (20) only in portions (36a, 36b) of the intersecting planes (35a, 35b). At that time, by setting areas of the portions (36a, 36b) to 30% or more and 90% or less relative to an area of each of the intersecting planes (35a, 35b), a projecting height of each of the projecting portions (30a, 30b) is 0.3 D or higher for functioning as a joint.

Abstract: The present invention has its object to provide an efficient, general use shaping technique for forming high strength sheet metal into a three-dimensionally complicated shape. Further, the present invention provides a working apparatus for shaping sheet metal comprising a die (also called a “punch”) which has a shape suitable for a shape of shaped sheet metal, a plurality of rolls which grip sheet metal (H) with the die to shape the sheet metal, roll movement mechanisms which makes the rolls independently move in a horizontal direction and make them independently ascend or descend in a vertical direction, and a roll angle setting mechanism which can change an angle by which the rolls are pressed against the die.

Abstract: A structure (10) for a front section of a vehicle body in a vehicle body (1) comprising a front chamber (3) disposed on the forward side of a vehicle interior (2) is provided with the following: a pair of front side members (11), located within the front chamber, that extend in the longitudinal direction of the vehicle body; a pair of strut towers (16) disposed on either side in the width direction of the front chamber and within which front wheel suspensions are disposed; and reinforcement members (20) that link the top of each strut tower with the front side members that face the strut towers, and that extend between the strut towers and the front side members. This configuration allows a structure for a front section of a vehicle body to be provided that can efficiently improve the rigidity of the vehicle body of an automobile against torsion and against lateral bending, and that can efficiently reduce the weight of the vehicle body by means of thickness reduction using a high-strength steel plate.

Abstract: A hydroforming apparatus and working method able to simply find a load path are proposed, which system and method use a mold in which contact sensors able to judge contact with a metal tube inside the mold are mounted at least at two different positions in the tube axial direction, perform a first step of axially pushing tube ends in a state with the internal pressure held at a constant value and stopping the progress of the axial pushing action when judging that among the contact sensors not yet in contact mounted at positions closest to the tube ends detect contact with the metal tube, next perform a second step of raising only the internal pressure while leaving the positions of the tube ends fixed and stopping the increase in the internal pressure when the contact sensor not yet in contact judges contact, next perform a third step of lowering the internal pressure to the value before raising it while leaving the positions of the tube ends fixed, and repeat said first step to third step until all of said c