Technical field
[0001]The present invention relates to a structural member and a method of manufacturing a motor vehicle.
BACKGROUND
[0002]Body of an automobile is constituted by a structural member that combined various. Most of the structural member is formed by press-molding a steel plate. Recently, the structural member of the vehicle (especially elongated members), to enhance the collision safety performance, it characteristics in three-point bending test is high is demanded. Therefore, various proposals have been made in the past.
[0003]
　For example, in the diagram of Patent Literature 1 (JP 2008-265609 JP) and Patent Document 2 (JP 2008-155749), the shock-absorbing member is disclosed including a portion steel plate folded in triplicate ing.
[0004]
　Patent Document 3 (JP 2011-67841), as an example of a collision is highly safe components, cites ridge cross-hat part a large number of the cross-section. Patent Document 4 (JP 2013-27894), the frame components is disclosed having a reinforcing portion formed at a connection portion between the top wall and the vertical wall portion. The reinforcing portion is comprised of a superposition unit rounded into a cylindrical shape.
[0005]
　Patent Document 5 (Japanese Patent No. 5,375,086) discloses a hollow frame body which is formed by roll forming. This edge portion is subjected to a compressive load of the hollow frame member, the inward ribs folded so as to overlap the chevron is provided.
CITATION
Patent Document
[0006]
Patent Document 1: JP 2008-265609 Patent Publication
Patent Document 2: JP 2008-155749 Patent Publication
Patent Document 3: JP 2011-67841 JP
Patent Document 4: JP 2013-27894 JP
Patent Document 5: Patent No. 5375086 JP
Summary of the Invention
Problems that the Invention is to Solve
[0007]
　By using the characteristic high structural member in a three-point bending test, a car to enhance the collision safety performance of motor vehicles it is possible or lighter. Therefore, currently, characteristics in three-point bending test is demanded a higher new structural member. In such circumstances, an object of the present invention is that the properties of the three-point bending test to provide a high structural member.
Means for Solving the Problems
[0008]
　Structural member according to an embodiment of the present invention is a structural member for a motor vehicle comprising a sheet of formed of a steel plate opening section of the press-molded product. The press molded product includes two vertical wall portions, and a top plate connecting the two vertical wall portions, the. At least a portion of the top plate, the protruding portion into which the steel sheet followed by the top plate portion projects is superposed is formed. It said projection, said to face the inside of the press-molded product, and so as to extend along the longitudinal direction of the press-formed article, projecting from the top plate.
[0009]
　Manufacturing method according to an embodiment of the present invention, the present embodiment is a method for producing a structural member for an automobile. This manufacturing method, two first portion serving as the two vertical wall portions, two second portions serving as the top plate, and a preform comprising a third portion serving as the protrusion, a first step of forming by deforming a single steel sheet, and a second step of forming said projecting portion and said top plate and said two longitudinal wall portions by press-molding the preform including. It said third portion is disposed between the two second portions, and are swollen toward the inside of the preform than the two second portions. The second step, so as to sandwich the third portion, and step (i) placing two movable punches on the inside of the preform, the two movable punches of said two first portions by pressing from the outside, and a step (ii) of forming the protrusion across the third part the two movable punches.
The invention's effect
[0010]
　According to the present invention, characteristics in three-point bending test is high structural member obtained. By using the structural member according to the present invention, the motor vehicle to enhance the collision safety performance of motor vehicles it is possible or lighter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011]
[1] Figure 1 is a perspective view schematically showing an example of a structural member of the present embodiment.
FIG. 2 is a diagram showing a cross section of the structural member shown in FIG. 1 schematically.
FIG. 3 is a cross-sectional view schematically showing another example of a structural member of the present embodiment.
[Figure 4A] Figure 4A is a cross-sectional view schematically showing another example of a structural member of the present embodiment.
[Figure 4B] Figure 4B is a cross-sectional view schematically showing another example of a structural member of the present embodiment.
[Figure 4C] Figure 4C is a perspective view schematically showing an example of a structural member of the present embodiment having the cross section shown in Figure 4B.
[FIG. 4D] FIG. 4D is a perspective view showing another example of a structural member of the present embodiment having the cross section shown in FIG. 4B schematically.
[FIG. 4E] FIG. 4E is a cross-sectional view schematically showing another example of a structural member of the present embodiment.
[FIG. 4F] FIG. 4F is a cross-sectional view schematically showing another example of a structural member of the present embodiment.
FIG. 5 is a cross-sectional view schematically showing an example of a preform produced by the production method of this embodiment.
[Figure 6A] Figure 6A is a diagram showing a starting state of the second step is schematically shown.
[Figure 6B] Figure 6B is a diagram showing a state in the second step schematically.
[Figure 6C] Figure 6C is a diagram showing the end of the state of the second step is schematically shown.
[Figure 7A] Figure 7A is a cross-sectional view showing a sample 2 of the present invention examples it was assumed in the simulation of Example 1 is schematically shown.
[Figure 7B] Figure 7B is a cross-sectional view showing a sample 3 of the present invention examples it was assumed in the simulation of Example 1 is schematically shown.
[Figure 7C] Figure 7C is a cross-sectional view showing a sample 1 of the comparative example assumed in the simulation of Example 1 is schematically shown.
[Figure 7D] FIG. 7D is a cross-sectional view schematically showing a comparative sample 4 that was assumed in the simulation of Example 1.
[8] FIG. 8 is a diagram schematically showing a three-point bending test of simulation in Example 1.
[9] FIG. 9 is a graph showing an example of a simulation result of Example 1.
[10] FIG 10 is a graph showing another example of a simulation result of Example 1.
FIG 11A] FIG 11A is a sectional view showing an example of deformation of the sample 1 in the test of Example 1 is schematically shown.
FIG 11B] FIG 11B is a cross-sectional view showing an example of deformation of the sample 2 in the test of Example 1 is schematically shown.
DESCRIPTION OF THE INVENTION
[0012]
　As a result of intensive studies, the inventors have, depending on the particular structure, characteristics in three-point bending test was newly found that improved. The present invention is based on this new finding.
[0013]
　Hereinafter, embodiments of the present invention will be described. As will be described by way of example embodiments of the present invention in the following description, the present invention is not limited to the examples described below. In the following description, there is a case to illustrate specific numerical values ​​and materials, as long as the effects of the present invention are obtained, may be applied other numerical values ​​and materials. In this specification, the term "cross section" is, unless otherwise indicated, it means a cross-section perpendicular to the direction (longitudinal direction) of the press-molded product (P) extends.
[0014]
　(Structural member for an automobile)
　structural member of the present embodiment is a structural member for an automobile. The structural member includes a single open section formed in the steel plate of the press-molded product. These structural members and the press molded product, respectively, may hereinafter be referred to as "structural member (S)" and "press-molded product (P)".
[0015]
　Press-molded product (P) comprises two vertical wall portion, and a top plate connecting the two vertical wall portions, the. At least a portion of the top plate, the protruding portion steel continuing from the top plate portion projects is superposed is formed. The protrusions, the following may be referred to as "protruding portion (Q)". Protrusion (Q), as toward the inside of the press-molded product (P), and, so as to extend along the longitudinal direction of the press-molded product (P), projecting from the top plate portion.
[0016]
　The inner press-molded product (P), two vertical wall portion, the top plate portion, and refers to a region surrounded by the imaginary plane connecting the ends of the two vertical wall portions.
[0017]
　Press-molded product (P) can be formed by deforming one steel sheet (steel sheet). It will be described later steel sheet used as a material.
[0018]
　The cross section of the protruding portion press-molded product excluding (Q) (P), the bottom may comprise a substantially flat U-shaped portion. If the press-molded product (P) includes a flange portion to be described later, the cross section of the press-molded product excluding the protruding portion (Q) (P) may be substantially hat shape.
[0019]
　From the viewpoint of the collision safety and weight reduction, the tensile strength of the steel sheet composing a press molded article (P) is higher, it is preferable. Or tensile strength of the steel sheet is 340 MPa (e.g., 490 MPa or higher, 590 MPa, or more 780 MPa, or more 980 MPa, or 1200MPa or higher) may be. There is no limitation on the upper limit of the tensile strength, it may be not more than 2500 MPa.
[0020]
　Usually, the press-molded product (P) as a whole has an elongated shape. The vertical wall portion, the top plate portion, and the later-described flange portion, both extending in the longitudinal direction of the press-molded product (P). Protrusion (Q) may be have been formed over the entire longitudinal direction of the press-molded product (P), or may be formed only on a part of the longitudinal direction of the press-molded product (P).
[0021]
　Top plate connects the two vertical wall portions. In another aspect, the top plate is a horizontal wall portion connecting the two vertical wall portions. Therefore, in this specification, it is possible to read as the top plate portion and the lateral wall portion. When placing the press-formed product (P) toward the lateral wall portion (top plate) downwards and can also be referred to as a bottom plate portion of the lateral wall portion. However, in this specification, reference to the case of arranging the lateral wall portion upward, referred to as the top plate portion of the lateral wall portion.
[0022]
　Angle between the top plate portion and the vertical wall portion is typically, 90 ° or near. The angle may be less than 90 °, usually greater than 90 °, may be in the range of 90 ° ~ 0.99 °. Two angles formed between each and the top portion of the two vertical wall portions may be different, but is preferably substantially the same (difference therebetween within 10 °), it may be the same.
[0023]
　Steel plates that are superimposed protrusions (Q) is generally in close contact. A very narrow gap even if there is a gap therebetween steel sheets, width of the gap is for example 1mm or less, preferably 0.5mm or less. Conventional press-formed article, there is what is groove-like recess in the top plate is formed, the protruding portion of this embodiment (Q) is different from the groove-like recess.
[0024]
　Usually, the top plate portion, the projecting portion (Q) is formed only one. However, a plurality of protrusions (Q) may be formed in the top plate portion. Usually, the projecting portion (Q) is formed so as to protrude perpendicularly to the top plate.
[0025]
　Width WQ protrusions (Q) may be in the range from 0.05 to 0.95 times the height HT of the vertical wall portion, it may be in the range of 0.05 to 1.50. If the ratio is greater than 1.0, it is greater than the height HT of the vertical wall portion width WQ. The width WQ and height HT, is described in Figure 2.
[0026]
　Protrusion (Q) may be formed at the center in the width direction of the top plate portion. Alternatively, the projecting portion (Q) may be formed in a position which is not at the center in the width direction of the top plate portion.
[0027]
　The width of the top plate portion and the width WT, the projecting portion (Q) is away from the center CT of the width direction of the top plate portion by a distance L. The distance L may be in the range of 0.05-0.45 times the width WT. The width WT and the distance L, described in FIG.
[0028]
　Steel plates that are superimposed protrusions (Q) may be fixed. For example, steel plates that are superimposed protrusions (Q) is may be welded, may be fixed in other ways. Examples of welding, resistance spot welding include laser welding, and arc welding.
[0029]
　Press-molded product (P) may comprise two flanges extending from the ends of the two vertical wall portions. In this case, the cross section of the press-molded product excluding the protruding portion (Q) (P) is, for example, substantially hat shape. Flanges normally extend substantially parallel to the top plate portion.
[0030]
　Structural members of the present embodiment (S) may further comprise other members. The other member, in the following also referred to as "member (M)" or "another member (M)". Member (M) is fixed to the press-formed product (P). There is no limitation on the method of fixing the member (M), may be a weld, it may be another fixing method. Examples of welding include examples described above.
[0031]
　Member (M), as a press molded article and the member and (M) constitutes a closed cross section, may be fixed to the press-formed product (P). In other words, member (M) may be closed the opening of the open cross-section of the press-molded product (P). For example, as press-formed product and the member and the (M) constitutes a closed cross section, member (M) may be fixed to the two flanges of the press-molded product (P). In another aspect, as the press molded product (P) and the member (M) constitutes a hollow body, members (M) to the two flange portions of the press-molded product (P) may be fixed.
[0032]
　Member (M) may be a metal plate, may be, for example, steel. Member (M) may be formed of a steel plate of the steel plate of the same kind which constitute press-molded article (P). Member (M) may be a plate-like member as called back plate, may be a molded product press-molded. For example, member (M) may have press-molded product (P) the shape of the same type with two flanges. In that case, it can be fixed and two flange portions of the press-molded product (P), and two flange portions of the members (M).
[0033]
　Structural members of the present embodiment (S) is, bumpers, side sill, a center pillar, A-pillar, roof rails, roof arches, or may be a belt line reinforcement or a door impact beam. Alternatively, the structural member (S) may be other structural members for automobiles.
[0034]
　(Method of manufacturing a structural member for an automobile)
　is described below the production method of the present embodiment. This manufacturing method is a method of manufacturing a structural member (S) of the present embodiment. Incidentally, the structural member (S) matters described in this embodiment, it is possible to apply to the production method of this embodiment, there may be omitted the duplicate description. Similarly, the matters described manufacturing method of this embodiment can be applied to a structural member (S) of the present embodiment.
[0035]
　The manufacturing method of this embodiment includes a first step and the second step. The first step, the first two of the two longitudinal wall portions, two second portions comprising a top plate portion, and a preform comprising a third portion comprising a protruding portion, of one a step of forming by deforming the steel sheet. Typically, the preform, there is no clear boundary between the first to third portions. However, there may be some boundaries between them. There is no particular limitation to the first step may be performed by a known press molding.
[0036]
　The second step is a step of forming a the protrusion two vertical wall portions and the top plate by press molding a preform. The third portion is disposed between the two second portions, and, than the two second partial swells toward the inside of the preform. Here, "inside the preform" refers to a region corresponding to the inside of the above-described press-molded product (P).
[0037]
　The second step includes a step (i) and step (ii). Step (i), so as to sandwich the third portion is a step of disposing the two movable punches on the inside of the preform. In one example, two movable punches are disposed along the first and second portions.
[0038]
　Step (ii), by pressing the two movable punches from the outside of the two first portion is a step of forming a protrusion across the third part two movable punches. Thus the second step is carried out, the press-formed product (P) is obtained. Press-molded product obtained by the second step (P) may be further post-processing.
[0039]
　In the following, there is a case in which the steel sheet is the starting material (steel plate) is referred to as "blank". Blank is typically a flat steel plate, having a planar shape corresponding to the shape of the press-molded product (P) to be formed. The thickness and properties of the blank is chosen depending on the characteristics required for the press-molded product. The thickness of the blank, for example may be in the range of 0.4 mm ~ 4.0 mm, may be in the range of 0.8 mm ~ 2.0 mm. The thickness of the press-molded product (P) is determined by the thickness and the processing step of the blank may be in the range of the thickness of the illustrated blank here.
[0040]
　Blank, tensile strength more than 340 MPa (e.g., 490 MPa or higher, 590 MPa, or more 780 MPa, or more 980 MPa, or 1200MPa or higher) is preferably a high-tensile steel plate (high-tensile steel). To reduce the weight of the structural member is preferably a tensile strength of the blank is high, more than 590 MPa (e.g. 980MPa or more, or more 1180 MPa) and more preferably. There is no limitation on the upper limit of the tensile strength of the blank, in one example is less than 2500 MPa. Tensile strength of the press-molded product (P) is usually higher than or equal to the tensile strength of the blank, may range exemplified herein. When the member (M) is made of steel plate, the thickness and tensile strength of the steel sheet, it is possible to select from the example above range.
[0041]
　If the tensile strength of the steel plate (blank) is not less than 590 MPa, the second step may be performed by hot stamping (hot press). If the tensile strength of the blank is high, cracking it tends to occur at the tip portion of the protruding portion by cold pressing. Therefore, in the case of using a blank tensile strength than 590 MPa (e.g., above 780 MPa), it is preferable to carry out the second step by hot stamping. Of course, even when the tensile strength is used blank of less than 590 MPa, the second step may be carried out by hot stamping. When performing hot stamping it may be used a blank having a known composition suitable therefor.
[0042]
　If the tensile strength of the blank wall thickness is more than 1.4mm above 590MPa, in order to prevent the cracking occurs in the protruding portion, it is particularly preferred to carry out the second step in the hot stamping. For the same reason, if the wall thickness at the tensile strength of the blank than 780MPa is 0.8mm or more, it is particularly preferred to carry out the second step in the hot stamping. Because heated steel sheet becomes high ductility, when performing the second step in hot stamping, it is less the thickness of the blank cracks even 3.2mm occurs.
[0043]
　Deformation in the first step is usually not so large. Therefore, regardless of the tensile strength of the blank, the first step can usually be carried out by cold working (for example, cold press). By performing the cold working can be molded accurately press-molded article. Further, by performing the cold working can be omitted the step of heating the blank, production efficiency is increased. However, the first step may be performed in the hot working (e.g., hot stamping) as necessary. It is preferable that at least the second step of the first step and the second step is a hot stamp. In a preferred example, the first step performed by cold working, a second step in hot stamping.
[0044]
　One example will be described below hot stamping. When performing hot stamping, first, heating a workpiece (blank or preform) to a predetermined quenching temperature. Quenching temperature is a temperature higher than the A3 transformation point to the workpiece austenitizing (more specifically Ac3 transformation point), it may be for example 910 ° C. or higher. Next, the workpiece is heated and pressed by a press device. Since the workpiece is heated, hardly cracked even by greatly deformed. Quenching the workpiece when pressed workpiece. This rapid cooling, the workpiece is hardened during pressing. Quenching of the workpiece may be performed by or cooling the mold, toward the mold to the workpiece or is sprayed with water. There is no particular limitation on the apparatus used procedure for hot stamping (heating and pressing, etc.) and it may be used known procedures and apparatus.
[0045]
　The following description with reference to the drawings this embodiment. The embodiments described below are exemplary, at least a portion of the configuration in the following embodiment, can be replaced with the above-described configuration. In the following figures, it may be omitted from redundant explanation are denoted by the same reference numerals to like parts. Furthermore, in the following figures, there is a case illustrating the gap between the steel plates that are superimposed protrusions in order to facilitate understanding, usually steel plates which are superimposed in the projecting portion is in close contact . Similarly, there is a case to illustrate the gap between the two steel plates being fixed.
[0046]
　(First Embodiment)
　In the first embodiment, an example of a structural member (S). A perspective view of a structural member 100 of the first embodiment schematically shown in FIG. Further, a vertical sectional view in the longitudinal direction of the structural member 100, shown schematically in FIG. In the following, referred to above (top plate side) in FIG. 2 and the upper press-molded product may be referred to a lower (flange portion) in FIG. 2 and lower press-molded product. In the example shown in FIGS. 1 and 2, the structural member (S) is only press-molded product (P), the press-formed product (P) comprises a flange portion. However, structural members of the present embodiment (S) may be include other member (M), may not include the flange portion.
[0047]
　Structural member 100 (structural member (S)) includes a press-molded product 110 (the press-molded product (P)). Press-molded product 110 is formed by a single steel plate. Press-molded product 110 includes two vertical wall portions 111, a top plate portion 112 connecting the two vertical wall portions, the. The top plate portion 112, the projecting portion 113 (protruding portion (Q)) of steel sheet followed from the top plate portion 112 is protruded is superposed is formed. Press-molded product 110 further comprises two flanges 114 extending from the ends of the two vertical wall portions 111.
[0048]
　By press-molded product 110 comprises two flanges 114, when a load is applied to the top plate 112, the effect of suppressing the leaning in the member outside of the flange portion 114 near the vertical wall portion 111. In other words, if there is no flange portion 114 to the press-molded product 110, the entire vertical wall 111 collapses the member outwardly, is difficult increased strength of the press-molded product 110. That is, when the press-molded product 110 is sill or the like, the collision characteristics less likely to increase.
[0049]
　Protrusion 113 is to face the inside of the press-molded product 110 and so as to extend along the longitudinal direction of the press-molded product 110, protrudes from the top plate portion 112. Protrusion 113 from the substantially central portion of the top plate portion 112 projects substantially perpendicular to the top plate portion 112.
[0050]
　Width WQ protrusions 113 (the length protruding portion 113 from the top plate portion 112 projects) and the height HT of the vertical wall portion 111 may satisfy the above relationship (ratio). Here, the height HT of the vertical wall portion 111, as shown in FIG. 2, the length from the end portion of the vertical wall portion 111 to the top plate portion 112.
[0051]
　1 and 2, the protruding portion 113, shows an example that is formed substantially at the center of the top plate portion 112. However, as shown in FIG. 3, the projecting portion 113 is not located at the center of the top plate portion 112 may be formed. Protrusion 113 shown in FIG. 3 is away from the center CT of the width direction of the top plate 112 by a distance L.
[0052]
　Structural member 100 may also include other members 120 in addition to the press-molded product 110 (another member (M)). Examples of structural members including another member 120, shown in Figure 4F from Figure 4A. In structural members 100 shown in Figure 4F Figures 4A, as the press-molded product 110 and the member 120 constitutes a closed cross section, member 120 is fixed to the press-molded product 110.
[0053]
　Structural member 100 shown in Figure 4A, includes a plate-like member 120. Member 120 is fixed to the two flanges 114 of the press-molded product 110.
[0054]
　Structural member 100 shown in Figure 4B, in cross section includes a generally hat-shaped member 120. Member 120 is press-molded article includes two flanges 124. As the inner inside and member 120 of the press-molded product 110 is opposed, the flange portion 124 of the flange portion 114 and the member 120 of the press-molded product 110 is secured.
[0055]
　A perspective view of an example the structural member 100 having a cross section shown in FIG. 4B shown in FIG. 4C, shows a perspective view of another example in FIG. 4D. In an example of FIG. 4C, the protruding portion 113 is formed over the entire longitudinal direction of the press-molded product 110. In an example of FIG. 4D, the protruding portion 113 is formed only on part of the length of the press-molded product 110.
[0056]
　Structural member 100 shown in FIG. 4E includes two press-formed product 110. One of the two press-molded product 110, which can be regarded as another member 120. Such that the inner ends of the two press-molded product 110 is opposed, between the flange portion 114 of the two press-formed article 110 is fixed.
[0057]
　Press-molded product 110 of the structural member 100 shown in FIG. 4F has no flange portion 114. Member 120 includes two vertical wall portions 121 and the top plate portion 122 connecting their longitudinal walls. In the example shown in FIG. 4F, as the direction of the top plate relative to the vertical wall portion is in the same direction, and the vertical wall portion 121 of the vertical wall portion 111 and the member 120 of the press-molded product 110 is secured.
[0058]
　In Figure 4A ~ Figure 4F, the illustrated example the protrusion 113 is formed in the central portion of the top plate portion 112. However, as shown in FIG. 3, the protruding portion 113 may be formed at a position other than the center portion to the top plate portion 112.
[0059]
　(Second Embodiment)
　In the second embodiment, an example of a manufacturing method of this embodiment. In the second embodiment describes an example of manufacturing a press-formed product 110 shown in FIGS. 1 and 2, although other press-molded product 110 can be similarly prepared. If the structural member 100 comprises a member 120 may be fixed to member 120 in any way to the press-molded article 110.
[0060]
　Describing a method of manufacturing a press molded article 110 below. First, by deforming a single steel sheet, to form a preform 210 shown in FIG. 5 (first step). Preform 210 includes a first portion 211 comprising two vertical wall portion 111, top plate 112 to become the two second portions 212, third portion 213 comprising a protruding portion 113, and two flange portions 114 comprises two fourth portions 214 a. The third portion 213 is disposed between the two second portions 212, and, than the two second portions 212 are swollen toward the inside of the preform 210. Preform 210 may be formed by a general press molding.
[0061]
　Next, a pre-molded article 210 and two vertical wall portions 111 and the top plate portion 112 by press-forming a protrusion 113 (second step). This second step will be described below.
[0062]
　The press forming apparatus 300 used in the second step, shown in Figure 6A. Press forming apparatus 300 includes two movable punches 301,2 one of the slide 302 includes an upper mold 303, and the plate 304. Movable punch 301 slides on the plate 304 in the horizontal direction. Slide 302 also moves in the horizontal direction. Slide 302 may be moved by a cam mechanism driven by a lowering of the upper die 303. Alternatively, slide 302 may be moved by an actuator such as a hydraulic cylinder.
[0063]
　In the second step, first, as shown in FIG. 6A, placing the preform 210 in press forming apparatus 300 (step (i)). In step (i), the movable punch 301, so as to sandwich the third portion 213 is placed inside of the preform 210. In an example of FIG. 6A, 2 one movable punch 301 is disposed along the first portion 211 and second portion 212.
[0064]
　Then step (ii) is carried out. A state in the step (ii) shown in Figure 6B, shows the end state of the step (ii) in FIG. 6C. As shown in FIGS. 6B and 6C, by pressing the two movable punches 301 from the outside of the two first portion 211 to form the protrusion 113 across the third section 213 with two movable punches 301 (step (ii)). By pressing the first portion 211 by the sliding-type 302 pushed the movable punch 301. At this time, the first portion 211 is moved in a state of being sandwiched between the movable punch 301 and the slide mold 302.
[0065]
　As shown in FIG. 6C, a third portion 213 sandwiched between two movable punches 301 is a protrusion 113 superimposed with. Incidentally, in carrying out step (ii), to press the second portion 212 of the top plate portion 112 a upper mold 303 is lowered as shown in FIG. 6C.
[0066]
　As described above, the press-molded product 110 is manufactured. Incidentally, when performing the second step by hot stamping heats the preform 210 before the second step to a predetermined temperature. This heating is performed, for example, by heating the preform 210 in a heating device. Then, when the press-molded by press forming apparatus 300, is cooled while pressed preform 210. In this way, the press-molding and quenching are performed. In this case, the press die of the press forming apparatus 300, coolable press die is used. Such a press type is known. Alternatively, it may be carried out cooling by jetting water from the press mold.
[0067]
　When the press-molded product 110 includes a plurality of protrusions 113, preform 210 includes a third portion 213 corresponding to the number of the projecting portions 113. In this case, it may be used three or more movable punch. Third portion 213 sandwiched between the adjacent two movable punches is projecting portion 113.
Example
[0068]
　The present invention will be described in more detail by examples.
[0069]
　(Example 1)
　In Example 1, the structural member of the present embodiment (S), were simulated three-point bending test. In the simulation, using a general-purpose FEM (Finite Element Method) software (LIVERMORE SOFTWARE TECHNOLOGY Co., Ltd., trade name LS-DYNA).
[0070]
　The cross-sectional view of a sample 2 of the present invention example used in the simulation in Example 1 are shown in Figure 7A. Structural member 100 of FIG. 7A, a press-molded product 110, consisting of welded plate-like member 120. in the flange portion 114. Size of Sample 2 as shown in FIG. 7A is as follows. Incidentally, in the sample 2, the projecting portion 113 is formed at the center of the top plate portion 112, and are formed over the entire longitudinal direction of the press-molded product 110.
[0071]
- projection of width WQ: 15 mm
Height of-vertical wall HT: 60 mm
- 2 one distance between the vertical wall portion (the width of the top plate portion) WT: 80 mm
- member 120 Width: 120 mm
· corner Ra and Rb curvature at a radius: 5 mm
· longitudinal length: 800 mm
[0072]
　The cross-sectional view of a sample 3 of the present invention embodiment, shown in Figure 7B. Sample 3 only in that steel plates constituting the projecting portion 113 is welded at the welded portion 113a is different from the sample 2.
[0073]
　As a comparative example, assuming the sample 4 shown schematically in samples 1 and 7D schematically shown in Figure 7C. Sample 1, a press-molded product 10, composed of a flange portion 14 welded to a plate-like member 20. of the press-molded product 10. Press-molded product 10 includes two vertical wall portions 11, a top wall 12 connecting them, and a flange portion 14. In the top wall 12 of the press-molded product 10, the protruding portion 13 which protrudes toward the inside of the press-molded product 10 is formed. However, the steel plate which constitutes the protruding portions 13 are not overlapped, the protruding portion 13 has a groove-like shape as a whole. The size of the sample 1 shown in FIG. 7C. Reference numeral R in Fig. 7C shows the radius of curvature. Sample 4, assuming a member of the hollow closed section which is formed by roll forming. Thus, the sample 4 consists of a single steel plate. In the center of the top plate portion 12 of the roll forming products 40 is formed with a protrusion 13, and is formed over the entire longitudinal roll forming products 40. The shape of the protruding portion of the roll forming products 40 was the same as sample 2 of the present invention embodiment.
[0074]
　Samples 1-4, tensile strength at a thickness of 1.4mm is assumed to be made of a steel plate is 1500 MPa. The press-molded product flange portion of (the press-molded product 110,10) and another member (member 120 and 20), spot welding: the assumption that fixed by (pitch 40 mm). Then, the simulation was performed in consideration of the breakdown and material fracture of the spot weld. Sample 4 (roll forming product 40) was seamless.
[0075]
　Three-point bending test method used in the simulation in FIG. 8 shows schematically a. Three-point bending test, placing the sample into two pivot 1, it was carried out by pressing the samples (from the top plate portion of each sample) from above by impactor 2. A collision direction of the impactor 2, indicated by an arrow in each of FIGS. 7A ~ Figure 7D.
[0076]
　In three-point bending test, the distance S between the two pivot 1 was 400 mm. The radius of curvature of the pivot 1 was 30 mm. The radius of curvature of the impactor 2 was 150mm. Collision speed of the impactor 2 was 7.5km / h. Impactor second width (paper to the length of the vertical direction in FIG. 8) were greater than the width of the top plate portion of the sample.
[0077]
　The simulation results shown in FIGS. Incidentally, simulation results of Sample 4 shown only in FIG. 10. The horizontal axis of FIG. 9 shows a displacement amount. Here, the amount of displacement, impactor 2 is a moving distance of the impactor 2 from contact with the sample. The vertical axis of FIG. 9 shows a load generated in the impactor 2. Further, in FIG. 10 shows the maximum value of the load.
[0078]
　As shown in FIG. 10, sample 2 and 3 of the present invention example, compared to Sample 1 and 4 of the comparative example was greater maximum load. This indicates that resistance to collision is high.
[0079]
　The cross-sectional shape of the sample 1 when the displacement amount is 40 mm (Comparative Example) and Sample 2 (Example invention) are shown respectively in FIGS. 11A and 11B. In the cross section of Sample 1 shown in FIG. 11A, the distance between the bottom and the member 20 of the projecting portion 13 was 21.6 mm. In the cross section of the sample 2 shown in FIG. 11B, the distance between the top plate portion 112 and the member 120 was 29.5 mm. This result indicates that the second moment of the sample 2 is large. That this result, towards the sample 2 of the present embodiment as compared with Sample 1 Comparative Example suggests that high resistance to impact.
Industrial Applicability
[0080]
　The present invention is applicable to structural members for automobiles.
DESCRIPTION OF SYMBOLS
[0081]
　100: Structure member
　110: press-formed product
　111: longitudinal wall portion
　112: the top plate portion
　113: protrusion
　114: flange portion
　115: protrusion
　120: other member

The scope of the claims

[Requested item 1]A structural member for a motor vehicle comprising a formed by a single steel plate opening cross section of the press-molded product,
　the press molded article,
　and two vertical wall portions,
　and a top plate connecting the two vertical wall portions , hints,
　at least a portion of the top plate portion, the projecting portion in which the steel sheet followed by the top plate portion projects is superposed is formed,
　the protrusion is on the inside of the press molded product directed way, and, so as to extend along the longitudinal direction of the press-formed article, projecting from the top plate, structural members for automobiles.
[Requested item 2]
　The protrusion is formed at the center in the width direction of the top plate, according to claim 1, structural members for automobiles.
[Requested item 3]
　Wherein the steel plates that are superimposed protrusions are welded, according to claim 1 or 2, structural members for automobiles.
[Requested item 4]
　The press molded article, comprising said two flange portions extending from the ends of the two vertical wall portions, according to any one of claims 1 to 3, structural members for automobiles.
[Requested item 5]
　Further include other members,
　the so press-molded product and said another member constitutes a closed cross section, said other member is fixed to the two flanges, according to claim 4, automobiles structural members of use.
[Requested item 6]
　According to any one of claims 1 to 5, a method for producing a structural member for an automobile,
　two first portion serving as the two vertical wall portions, the two first of the said top plate 2 parts, and a preform comprising a third portion serving as the protrusion, a first step of forming by deforming a single steel sheet,
　said by press-molding the preform 2 one of and a second step of forming a vertical wall portion and the top plate portion and the protruding portion,
　the third portion, wherein disposed between the two second portions, and said two first than second portion bulges towards the inside of the preform,
　the second step,
　the third to sandwich the portion, placing the two movable punches on the inside of the preform ( and i),
　by pressing the two movable punches from the outside of said two first portions Therefore, the containing and the two movable punches third step of forming the protrusion across the portion (ii), a manufacturing method of a structural member for an automobile.
[Requested item 7]
　Wherein at least the second step of the first step and the second step is a hot stamping method according to claim 6.