Technical field
[0001]The present invention, structural members for automobile using press-molded article and the same, and a method of manufacturing press-molded products.
BACKGROUND
[0002]In structural members of vehicles (especially elongated members), to enhance the collision safety performance, it characteristics in three-point bending test is high is demanded. Therefore, from the past, it has been made various proposals.
[0003]
　FIG Patent Document 1 (JP 2008-265609 JP) and Patent Document 2 (JP 2008-155749), the impact-absorbing member including a portion steel plate folded in triplicate disclosed .
[0004]
　Patent Document 3 (JP 2010-242168) discloses a method of forming a recess in the wall of a substantially hat-shaped member. In this method, to form a recess by pressing the walls at the feed rollers. Therefore, in this method, the portion that protrudes from the wall portion before forming the concave portion is not formed.
[0005]
　Patent Document 4 (JP 2011-67841), Patent Document 5 (JP 2011-83807) and Patent Document 6 (JP 2013-27894 JP) is high-tensile steel in order to improve the safety of motor vehicles application but has been studied tensile steel of wood is stated, that there is a problem in terms of workability (the document paragraph [0002]). Therefore, Patent Documents 4 and 5, as an example of even part is higher collision safety without the use of high-tensile steel, cites ridge large number sectional hat-shaped part of the cross section (Patent Documents 4 and 5, paragraphs [ 0003]). Further, Patent Documents 4 to 6, as an example of even crash high safety component without using a high-tensile steel, cites component recesses in the longitudinal direction (bead portion) is formed (Patent Documents 4 and 5 paragraph [0003], paragraph of Patent Document 6 [0004]).
[0006]
　Patent Document 4, a high safety component without using a high-tensile steel, discloses a hollow cylindrical component connection region between the vertical wall and the top wall are flared outwardly. To increase the number of the ridge line in the cross section, the overhanging portion is not folded.
[0007]
　Patent Document 5, a method for producing a highly safe components without using a high-tensile steel, the vertical wall portion, the method for producing a cross-hat part bead groove-shaped in the longitudinal direction is formed discloses.
[0008]
　Patent Document 6, as a highly safe components without using a high-tensile steel, discloses a frame part 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 ([0015] of Patent Document 6).
CITATION
Patent Document
[0009]
Patent Document 1: JP 2008-265609 Patent Publication
Patent Document 2: JP 2008-155749 Patent Publication
Patent Document 3: JP 2010-242168 Patent Publication
Patent Document 4: JP 2011-67841 JP
Patent Document 5: JP 2011-83807 JP
Patent Document 6: JP 2013-27894 JP
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　Currently, structural members that can enhance the collision safety performance are demanded. In other words, the characteristics in three-point bending test is higher press molded product is required. In such circumstances, one object of the present invention, three-point bending characteristics in the test higher press-and structural member for an automobile using the same, and, for producing the press molded product it is to provide a manufacturing method.
Means for Solving the Problems
[0011]
　Press-molded product according to an embodiment of the present invention is a press-formed article formed from a sheet of steel. The press molded product is, the two vertical wall portions and the top plate portion connecting the two vertical wall portions, at least one of the boundary portion of the two boundary portion connecting said top plate portion and the vertical wall portion including, at least one projection that projects from. In the projecting portion, and the steel sheet and the steel sheet extending from said vertical wall portion extending from said top plate portion, said protruding from boundary portions as superimposed at least a tip in overlapping portions of the projecting portion. The protrusion is present in the longitudinal direction of at least a portion of the press-molded product. Angle is greater than 180 ° formed between the top plate portion and the overlapping portions are.
[0012]
　Structural member according to an embodiment of the present invention is a structural member for a motor vehicle comprising a press-molded product of the present embodiment, the other member. The press molded product and said other member so as to form a closed cross section, said other member is fixed to the press-molded product.
[0013]
　Manufacturing method according to an embodiment of the present invention is a method for manufacturing a press molded product of the present embodiment. The manufacturing method of preform comprising a second portion serving as the two becomes the vertical wall portion 2 of the first portion and the top plate portion, a first step of forming by deforming the steel sheet by press-molding the preform, and a second step of forming the press-molded product. The preform includes a surplus portion for forming the protrusion. In the second step, to form the overlapping portions by overlapping at least a portion of the steel sheet forming the surplus portion.
The invention's effect
[0014]
　According to the present invention, three-point bending characteristics in the test higher press-and structural member for an automobile using the same obtained. Further, according to the manufacturing method of this embodiment can be easily produced the press-molded product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015]
[1] Figure 1 is a perspective view schematically showing an example of the press-molded product of the present embodiment.
FIG. 2 is a sectional view showing a press-molded article shown in FIG. 1 schematically.
[Figure 3A] Figure 3A is a partially enlarged view of the cross section shown in FIG.
[Figure 3B] Figure 3B is an enlarged view of FIG 3A.
[Figure 4A] Figure 4A is a cross-sectional view schematically showing an 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 having a cross section shown in Figure 4B.
[FIG. 4D] FIG. 4D is a perspective view showing another example of a structural member having a 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 4G] FIG 4G is another example of a structural member of the present embodiment is a cross-sectional view schematically showing.
FIG 4H] FIG. 4H, another example of a structural member of the present embodiment is a cross-sectional view schematically showing.
FIG. 5 is a cross-sectional view schematically showing an example of a preform formed in the manufacturing method of this embodiment.
[Figure 6A] Figure 6A is a cross-sectional view schematically showing one step in the second step in an example of the manufacturing method of this embodiment.
[Figure 6B] Figure 6B is a cross-sectional view showing a step subsequent to the first step of FIG. 6A schematically.
[Figure 6C] Figure 6C is a cross-sectional view showing a step subsequent to the first step of FIG. 6B schematically.
FIG 6D] FIG. 6D is a cross-sectional view showing a step subsequent to the first step of Figure 6C schematically.
FIG 6E] FIG 6E is a cross-sectional view showing a step subsequent to the first step of FIG. 6D schematically.
[Figure 7A] Figure 7A is a cross-sectional view schematically showing an example of one step of the method for forming a flange portion.
[Figure 7B] Figure 7B is a cross-sectional view showing a step subsequent to the first step of FIG. 7A schematically.
[FIG. 8A] Figure 8A is a cross-sectional view showing the shape of the sample 1 (Comparative Example) used in Example schematically.
[Figure 8B] Figure 8B is a cross-sectional view showing the shape of a sample 2 (Example 1) used in Example schematically.
[Figure 8C] Figure 8C is a cross-sectional view schematically showing a part of the sample of the present embodiment used in Examples.
[Figure 8D] Figure 8D is a cross-sectional view showing a part of another sample of the present embodiment used in example schematically.
FIG 8E] FIG. 8E is a cross-sectional view showing a part of another sample of the present embodiment used in example schematically.
FIG 8F] FIG 8F is a cross-sectional view showing a part of another sample of the present embodiment used in example schematically.
FIG 8G] FIG. 8G is a cross-sectional view showing a shape of a sample 3 was used in Example (Reference Example 2) schematically.
[9] FIG. 9 is a diagram schematically showing a three-point bending test of simulation in the examples.
FIG. 10 is obtained by the simulation of Example is a graph showing an example of the relationship between the displacement amount and the load.
FIG. 11 is obtained by the simulation of Example is another graph showing an example of the relationship between the displacement amount and the load.
FIG. 12 is obtained by the simulation of Example is a graph showing the energy absorption amount of each sample.
FIG. 13 is obtained by the simulation of Example is a graph showing the maximum load for each sample.
DESCRIPTION OF THE INVENTION
[0016]
　As a result of intensive studies, the present inventors have newly found that improved characteristics with respect to collision by a particular structure. The present invention is based on this new finding.
[0017]
　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.
[0018]
　(Press molding)
　press molded product of the present embodiment is a press-formed article formed from a sheet of steel. In the following, the press-molded product, sometimes referred to as "press-molded product (P)". Press-molded product (P) includes two vertical wall portions, and a top plate connecting the two vertical wall portions, at least one of the boundary portion of the two boundary portion connecting the vertical wall portion and a ceiling plate portion including, at least one protrusion protrudes. The protrusion, the steel plate extending from vertical wall portion (steel sheet continues from the vertical wall portion) and the steel plate extending from the top plate (steel plate continuing from the top plate portion), but are superimposed in overlapping portions at the least the tip of the protruding portion protrudes from the boundary portion as. Protrusion is present in the longitudinal direction of at least a portion of the press-molded product (P). Angle is greater than 180 ° formed between the portion overlaid with the top plate. The angle between the portion overlaid with the top plate portion, the following may be referred to as "angle X". For more information about the angle X, described in the first embodiment. Incidentally, if it is not part of the top plate portion is flat to such minute irregularities on the top plate portion is formed, the angle when considered as flat as a whole top plate, and the angle of the top plate portion .
[0019]
　Press molded product of the present embodiment (P) may comprise two flanges extending from the ends of the two vertical wall portions (an end portion opposite to the top plate side).
[0020]
　In at least the tip portion of the protruding portion, and the steel plate extending from the steel plate and a vertical wall portion extending from the top plate portion is arranged in a double superimposed. In this specification, a portion that is superimposed on the steel plate double at the projecting portion, sometimes referred to as "superposition unit". At the tip of the projecting portion is bent steel plate.
[0021]
　Press molded product of the present embodiment (P) can be formed by deforming one steel sheet (steel sheet). Specifically, it can be produced press-molded product (P) of the present embodiment by press-forming a sheet of steel plate by the method of this embodiment. It will be described later steel sheet used as a material.
[0022]
　Press molded product of the present embodiment (P) has an elongated shape as a whole. The vertical wall portion, the top plate portion, the flange portion, and the projection are both extend along the longitudinal direction of the press-molded product (P). Protrusion may be 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).
[0023]
　Hereinafter, the two vertical wall portions, an imaginary surface connecting the ends of the two vertical wall portions, and the area surrounded by the top plate may be referred to as "inner press-molded product (P)". Furthermore, with the inner sides of the vertical wall and the top plate there is a case where the region opposite is referred to as "outside of the press-molded product (P)".
[0024]
　Top plate connects the two vertical wall portions. More specifically, the top plate portion, connecting the two vertical wall portion via the projecting portion. 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.
[0025]
　Angle Y formed by the top plate portion and the vertical wall portion is typically, 90 ° or near. The angle Y, described in the first embodiment. Angle Y is may be less than 90 °, usually greater than 90 °, may be in the range of 90 ° ~ 0.99 °. Two angles Y may be different but is preferably substantially the same (difference therebetween within 10 °), it may be the same.
[0026]
　Press molded product of the present embodiment (P) preferably includes two protrusions projecting from each of the two boundary. In this case, the projecting portion, one from each of the two boundary portion protrudes. Angle X in two projections is preferably approximately the same (the difference between the two is within 10 °), it may be the same. Two projections are preferably, their shape in a cross section perpendicular to the longitudinal direction are formed to be axisymmetric. However, they may not be formed so as to be axisymmetric.
[0027]
　Angle X formed by the superposition with the top plate portion may be less than or equal 270 ° larger than 180 °.
[0028]
　In press-molded product of the present embodiment (P), length of the projecting portion in a cross section perpendicular to the longitudinal direction, than 3mm it may be (for example 5mm or more, 10 mm or more, or 15mm or higher). Although there is no particular limitation on the upper limit of the length, may be for example 25mm or less.
[0029]
　In the press-molded product (P) of the present embodiment, the projecting portion, and the steel plate extending from steel plate and the top plate portion extending from the vertical wall portion may be welded. For example, the steel sheet has become doubly overlapping portions may be welded by spot welding or laser welding. Also, the root of the protrusion in (a top plate portion and the vertical wall portion, the boundary of the projecting portion), even if the steel sheet extending from the steel plate and the top plate portion extending from the vertical wall portion is arc welding (fillet welding) good. The length of the two projections may be the same or may be different.
[0030]
　In press-molded product (P) of the present embodiment, the tensile strength of the steel sheet constituting the press-molded product is more than 340 MPa (e.g., 490 MPa or higher, 590 MPa, or more 780 MPa, or more 980 MPa, or 1200MPa or higher) may be. When performing the second step of the manufacturing method described later by hot stamping, the tensile strength of the press-molded product may be higher than the tensile strength of the steel sheet (blank) is the material.
[0031]
　Press molded product of the present embodiment (P) can be utilized in various applications. For example, various mobile means (automobile, motorcycle, railway vehicles, ships, aircraft) can be used for structural members and the structural members of various machines. Examples of automotive structural members, side sill, a pillar (front pillar, front pillar lower, center pillar, etc.), a roof rail, a roof arch, the bumper beam, beltline reinforcement, and door impact beams included, other than those it may be a structural member.
[0032]
　(Structural member for an automobile)
　embodiment of the press-molded product (P) may be directly used as various structural members. That is, structural members for automobiles of the present embodiment includes a press-molded product (P) of the present embodiment. The structural member for an automobile of this embodiment, hereinafter sometimes referred to as "structural member (S)." The structure member to be described below, can be used as a structural member of the products other than automobiles.
[0033]
　Structural members of the present embodiment (S) is press-molded product and (P), may include other members. The other member, in the following, sometimes referred to as "another member (M)" or "member (M)". As the press-molded product (P) and the other member (M) constitutes a closed cross section, another member (M) may be fixed to the press-formed product (P). When the press-molded product (P) comprises the two flanges, so press-molded product (P) and another member (M) constitutes a closed cross section, another member (M) has two flanges it may be fixed to.
[0034]
　Members (M) are, for example, members made of steel plate (steel plate member). The steel sheet which constitutes the member (M), may be used steel steel plate and the same type constituting a press molded article (P). An example of a member (M) is a press-molded product of the present embodiment (P). In that case, two of the press-molded product (P) are fixed to each other.
[0035]
　There is no limitation on the method of fixing the press-molded product (P) and another member (M), may be a weld, it may be another fixing method. Examples of welding include examples described above.
[0036]
　(Method of manufacturing press-molded product (P))
　the production method of the present embodiment is a method for producing a press-molded product (P) of the present embodiment. For the matters described press-molded product (P) of the present embodiment is applicable to the production method of this embodiment, there may be omitted the duplicate description. Also, matters described method for manufacturing the present embodiment can be applied to a press-molded product (P) of the present embodiment.
[0037]
　The manufacturing method of this embodiment includes a first step and the second step. In the first step, a preform comprising a second portion to be the two of the two vertical wall portions the first portion and the top plate are formed by deforming the steel sheet. In the second step, by press molding the preform to form a press-molded product (P).
[0038]
　Preform includes a surplus portion for forming the protrusion. In a second step, to form the overlapping portion by overlapping at least a portion of the steel plate which constitutes the surplus portion (deformed steel sheet). Typically, the preform, but there is no clear boundary between the surplus portion and other portions, there may be some boundaries between them.
[0039]
　Preform, a cross section perpendicular to the longitudinal direction may include a U-shaped portion is U-shaped. The U-shaped portion, two longitudinal wall portions, the top plate portion, and the projecting portion. In the following description, the term "cross section" means a cross section in a direction perpendicular to the longitudinal direction as a rule.
[0040]
　There is no particular limitation to the first step may be performed by a known press molding. The second step will be described later. The resulting press-molded article by the second step may be worked up further. Obtained by the second step (or later obtained by post-processing) press-molded product may be used as it is, or may be used in combination with other members.
[0041]
　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 produced. The thickness and properties of the blank is chosen depending on the characteristics required for the press-molded product (P). For example, the press-molded product (P) is the case of the structural members of automotive blank corresponding thereto is selected. 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. Thickness of the press-molded product of the present embodiment (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.
[0042]
　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 2000 MPa. Tensile strength of the press-molded product of the present embodiment (P) is usually higher than or equal to the tensile strength of the blank, may range exemplified herein.
[0043]
　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.
[0044]
　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.
[0045]
　Patent Documents 4 and 5 and 6, a manufacturing method using a hot stamping is not disclosed. However, as described above, in the case of using a high-tensile steel, it is preferable to carry out the second step by hot stamping.
[0046]
　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). However, the first step may be performed in the hot working (e.g. hot pressing) if necessary. In a preferred example, the first step performed by cold working, a second step in hot stamping.
[0047]
　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.
[0048]
　The second step, the lower mold, the upper mold, and may be performed using a press die including a slide type movable horizontally towards the lower mold. In this case, the second step may comprise the steps of (i) and step and (ii). Step (i) is a step of constraining the two first portions (portion to be a vertical wall portion) by the lower mold and the slide mold. Step (ii), in a state in which detained two first portions, by the upper mold and the slide mold while pressing the second portion by the lower mold and the upper mold (the portion comprising a top plate portion) a step of forming a press-molded product by pressing a surplus portion.
[0049]
　Lower die may comprise a lower mold body, and a pad connected to the lower mold body via a telescopic mechanism. In this case, the manufacturing method of this embodiment may include a step (iii) and step (iv). Step (iii) after step (ii), by raising the upper die and pad with releasing the restriction by the lower mold and the slide mold (restraint of the vertical wall portion), in the step of raising the press-formed product is there. Step (iv) is a step of separating the slide from the lower die after the step (iii).
[0050]
　When the press-molded product (P) is, comprising two flange portions extending from the ends of the two vertical wall portions, the manufacturing method of the present embodiment, after the second step, it includes a third step of forming a flange portion But good. An example of a method of forming the flange portion, is described in the third embodiment.
[0051]
　The following description with reference to the accompanying drawings, embodiments of the present invention. The embodiments described below are exemplary and can apply various variations described above. In the following description, it may be omitted from redundant explanation are denoted by the same reference numerals to like parts. Furthermore, in the following drawings, for ease of understanding, there is a case to illustrate the gap between the steel plates that are superimposed superposed section, typically, the steel plates that are superimposed overlapping portions contact doing.
[0052]
　(First Embodiment)
　In the first embodiment, an example of the press-molded product of the present embodiment (P). A perspective view of the press-molded product 100 of the first embodiment schematically shown in FIG. Further, a vertical sectional view in the longitudinal direction of the press-molded product 100, shown schematically in FIG. Furthermore, the cross-sectional view of the vicinity protrusions 115, schematically shown in FIGS. 3A and 3B. In the following description, referred to as upper upper (top plate portion 112 side) of the press-molded product of the present embodiment (P) 100 in FIG. 2, the press molding of the present embodiment the lower (flange portion 113 side) in FIG. 2 sometimes referred to as lower goods (P).
[0053]
　Press-molded product 100 is formed by a single steel plate 101. Referring to FIGS. 1 and 2, the press-molded product 100 includes two vertical wall portions 111, top plate 112, two flange portions 113,2 one protrusion 115. The vertical wall portion 111, top plate 112 and the flange portion 113, are each flat. The top plate 112, linking two vertical wall portion 111 via the two protrusions 115. In the example shown in FIG. 2, the two flanges 113, from the lower end of two vertical wall portion 111, and extends substantially horizontally outwardly. That is, the flange portion 113 is substantially parallel to the top plate portion 112.
[0054]
　Referring to FIGS. 2 and 3B, the protruding portion 115, a boundary portion connecting the vertical wall portion 111 and the top plate portion 112 (see dotted lines in FIG. 2), and protrudes outward. In the present embodiment, the portion that is bent toward the upper end side of the vertical wall portion 111 to the protrusion 115 and the corner portion 114. That is, from the point where the vertical wall portion 111 begins to flex toward the protruding portion 115, the portion up to the upper end of the overlapping portion 115d of the protrusion 115, the corner portion 114.
[0055]
　Protrusion 115, and the steel plate 101a extending from the top plate portion 112, and the steel plate 101b that extends from the vertical wall portion 111, made of. A portion from the bent portion of the end portion of the top plate portion 112 extends outwardly a steel plate 101a, a portion bent at the corner portion 114 extending from the vertical wall portion 111 extending outwardly and steel 101b. Steel 101a is bent at the distal end 115t of the projecting portion 115, are connected to the steel plate 101b. Upper surface side and the steel plate 101b of the lower steel plate 101a is in close contact with mutually superimposed between the projecting portion 115 from the corner portion 114. Each steel plate 101a and steel plate 101b, which is part of the steel plate 101. Section of the press-molded product 100 excluding the protruding portion 115 (a cross section perpendicular to the longitudinal direction) shape is substantially hat shape.
[0056]
　As shown in FIGS. 3A and 3B, in cross section, the angle between the overlapping portions 115d and top plate 112, an angle X. More specifically, the angle X has a surface 112s of the upper side of the surface of the top plate 112, which is the angle between the upper side of the surface 115us of the surface of the overlapping portion 115 d. Here, in the cross section, if the overlapping portion 115d of the protrusion 115 includes a linear shape (e.g. see FIG. 8C, FIG. 8D and FIG. 8E), and the surface 115us in the linear shape of the overlapping portions 115d, top plate the angle between the surface 112s is formed in 112 an angle X. Further, as shown in FIG. 8F, when the cross-sectional shape of the overlapping portion 115d does not include a linear shape, of the upper side of the surface of the steel plate 101a, an end portion of the tip portion 115t side of the overlapping portion 115d, and end 101at. A virtual tangent at the end 101At (dotted line extending in the vertical direction in FIG. 8F), the angle between the surface 112s of the top plate 112 an angle X.
[0057]
　When the angle X is greater than 90 °, from above the top plate 112 when viewed press molded article 100, the steel sheet 101b constituting the protruding portion 115 is no longer visible by steel 101a. Such moieties may be referred to as negative corners. In another aspect, the negative corners, when trying to press molding only upper and lower mold, a portion serving as inverse gradient.
[0058]
　Angle X formed by the top plate portion 112 and the overlapping portion 115d is preferably 180 ° greater than 270 ° or less. Within the angle X is within this range, without overlapping portion 115d of the protrusion 115 (the inner side of the steel plate 101b) are in close contact with the vertical wall portion 111, a gap between the protruding portion 115 and the vertical wall portion 111 secured It is. Thus, when the collision load applied to the top plate 112, stress applied to the top plate 112 is dispersed in the protrusion 115 and the corner portion 114, so as to maintain the shape of the corner portion 114 vertical wall It added to section 111. Thus it will be subjected to stresses throughout the vertical wall portion 111, thereby improving the crashworthiness. Moreover, and the corner portion 114 is locally deformed, since the vertical wall portion 111 as a fulcrum corner 114 is prevented and that fall outside, even when the vertical wall portion 111 is deformed, the inner deformed so as to fall in.
[0059]
　On the other hand, when the overlapping portion 115d of the protrusion 115 is in close contact with the vertical wall portion 111, when the collision load applied to the top plate portion 112, vertical wall 111 that stress through the overlapping portions 115d It added concentrated adhesion portion. Thus vertical wall portion 111 is deformed so as to fall inward locally from the contact portion between the overlapping portions 115 d. In this case, the collision characteristics are lowered.
[0060]
　Figure 2 shows an example of a case where the angle Y formed between the vertical wall portion 111 and the top plate portion 112 is 90 °. Here, the angle Y is an angle shown in FIG. 2, i.e., inside of the press-molded product 100, which is the angle between the vertical wall portion 111 and the top plate portion 112.
[0061]
　As shown in FIG. 2, the corner section 116 connecting the vertical wall portion 111 and the flange portion 113 is preferably a shape that its cross section is rounded. By having a shape corners 116 have been rounded, it is possible to prevent the buckling in the corner portion 116.
[0062]
　As shown in FIGS. 2 and 3B, (corresponding to Ra in Fig. 8B.) Corner 114 of the boundary between the steel plate 101b and the vertical wall portion 111 which constitutes the projecting portion 115 is preferably curved. By the corner portion 114 and the curved surface, the stress applied from above the top plate portion 112 to be dispersed in the corner portion 114, the corner portion 114 can be prevented from buckling. In the cross section perpendicular to the longitudinal direction of the press-molded product 100, the radius of curvature r of the corner portion 114 may be in the range of 3 ~ 15 mm (such as in the range of 3 ~ 10 mm). However, the curvature radius r is shorter than the length of the projecting portion 115 in the cross section.
[0063]
　In another aspect, the lower limit of the radius of curvature r of the corner portion 114 may be either greater value among the half and 1mm in thickness of the steel sheet 101. The upper limit of the radius of curvature r of the corner portion 114 may be 10 times the plate thickness. The radius of curvature r is too small, the stress dispersion in the corner portion 114 is not performed sufficiently, there is a risk of breaking the corner portion 114 to the starting point at the time of collision. In addition, by the radius of curvature r is too small, overlapping portion 115d of the protrusion 115 is in close contact with the vertical wall portion 111, there is a possibility that the vertical wall portion 111 to concentrate the stress at the time of collision is the adhesion portion is broken. On the other hand, if the radius of curvature r is too large, stress applied to the top plate portion 111 is hardly transmitted to the protrusion 115 through the corner portion 114, fades improvement in crashworthiness by providing the projecting portion 115. In order to improve the collision characteristics, the gap between the protruding portion 115 and the vertical wall portion 111, at a minimum, it is desirable that any larger value of the thickness of half and 1 mm.
[0064]
　Furthermore, the curvature radius r of the corner portion 114, more specifically, in a cross section perpendicular to the longitudinal direction of the press-molded product 100 refers to a radius of curvature at the outer surface 114s of the corner portion 114. Outer surface 114s of the corner portion 114 is a surface which is located the upper end 111sp of the outer surface 111s of the vertical wall portion 111, over the upper end 101bsp surface 101bs of the steel sheet 101b constituting the projecting portion 115.
[0065]
　(Second Embodiment)
　In the second embodiment, an example of the structural member using a press molded article (P) of the present embodiment (S). Examples of structural members (S), shown in FIGS. 4A ~ Figure 4H. Figure 4A, 4B, 4E ~ 4H is a diagram schematically showing a cross section perpendicular to the longitudinal direction of the structural member (S). 4C and 4D are perspective views schematically showing a structural member (S). Any structural member (S) is shown in FIGS. 4A ~ Figure 4H, having a closed cross section.
[0066]
　Structural member 200 shown in Figure 4A, includes a press-molded product 100 having the protrusions 115, plate member 210 and the (other member (M)). As the press-formed product 100 and the member 210 constitutes a closed cross section, member 210 is fixed to the two flanges 113 of the press-molded product 100.
[0067]
　Structural member 200 shown in FIG. 4B, includes a press-molded product 100 having the protrusions 115, the other member 210. Member 210 in cross section a substantially hat-shaped member, having two flanges 213. As the inner inside and member 210 of the press-molded product 100 is opposed, the two flanges 113 of the press-molded product 100 is secured to the two flanges 213 of the member 210.
[0068]
　A perspective view of an example a structural member having a cross-section of Figure 4B shown in FIG. 4C, shows a perspective view of another example in FIG. 4D. In structural member 200 of FIG. 4C, the protruding portion 115 is formed over the entire longitudinal direction of the structural member 200. In structural member 200 of FIG. 4D, the protruding portion 115 is formed only on part of the length of the structural member 200.
[0069]
　Structural member 200 shown in FIG. 4E includes two press-formed product 100 with a protrusion 115. Such that the inner ends of the two press-molded product 100 is opposed, flange portion 113 to each other is fixed. Two one of the press-molded product 100 one of the press-molded product 100, which can be regarded as another member (M).
[0070]
　Structural member 200 shown in FIG. 4F includes a press-molded product 100 having a protrusion 115, and a member 210. Press-molded product 100 includes two vertical wall portions 111 and the top plate portion 112 that connects them. Member 210 includes two vertical wall portions 211 and top plate 212 connecting them. In structural member 200 shown in FIG. 4F, none of the press-molded product 100 and member 210 does not include a flange portion. In the example shown in FIG. 4F, so that the direction of the top plate relative to the vertical wall portion is in the same direction, and the vertical wall portion 211 of the vertical wall portion 111 and the member 210 of the press-molded product 100 is secured.
[0071]
　Structural member 200 shown in FIG. 4G differs from the structural member 200 that only the direction of fixing the member 210 is shown in FIG. 4F. In the example shown in FIG. 4G, respective inner each other so as to face the vertical wall portion 211 of the vertical wall portion 111 and the member 210 of the press-molded product 100 is secured.
[0072]
　Structural member 200 shown in FIG. 4H includes two press-formed product 100 with a protrusion 115. Neither of the two press-molded product 100 does not include a flange portion. Such that the inner ends of the two press-molded product 100 is opposed, between the vertical wall portion 111 of the press-molded product 100 is secured.
[0073]
　(Third Embodiment)
　In the third embodiment, a description will be given of a method of the invention for producing a press-molded product (P). According to this manufacturing method, by forming a preform in a first step, pressing the preform in a second step. This allows manufacturing a press molded article (P) 100 of the present embodiment. In the third embodiment, an example of performing a second step by hot stamping.
[0074]
　First, in a first step, a preform 301 comprising two parts the two vertical wall portions 111 (first portion) and become part top plate portion 112 (second portion), deform the steel sheet formed by. The first step can be carried out by the method described above (e.g., pressing). An example of a cross section (cross section perpendicular to the longitudinal direction) of the preform 301 which is formed in the first step, shown schematically in FIG.
[0075]
　Section of the preform 301 is substantially U-shaped (in Fig. 5 vertically reversed). Preform 301 includes two first portions 301a of the two longitudinal wall portions 111, and a second portion 301b serving as a top plate portion 112. Preform 301 further includes a portion (excess portion 301c) comprising a projecting portion 115. FIG. 5 shows the preform 301, shows the case including a third portion 301d of the flange portion 113. When producing a press-molded product (P) having no flange portion, the preform 301 does not include the third portion 301d.
[0076]
　The second step is carried out by hot stamping. First, the preform 301 is heated to a (higher temperature 80 ° C. or higher than, for example, Ac3 transformation point) Ac3 transformation point or higher. This heating is performed, for example, by heating the preform 301 in a heating device.
[0077]
　Then, the preform 301 is heated pressing by a press device. An example of a press-type configuration used for press working shown in FIG. 6A. Press apparatus includes a pair of press dies 10, the plate 13 and two slide 14,.
[0078]
　A pair of press dies 10 comprises an upper die 11 (die) and a lower mold 12 (punch). Lower mold 12 includes a lower die body 12a and the pad 12b. Pad 12b is connected to the lower die main body 12a via the extendable telescopic mechanism 12c. The telescopic mechanism may be a known stretching mechanism such as springs and hydraulic cylinders.
[0079]
　Slide 14 slides on the plate 13 in the horizontal direction. Slide 14 can be slid with a cam mechanism in conjunction with the movement of the press die 10. Alternatively, slide 10 may be slid by using an actuator such as a hydraulic cylinder.
[0080]
　It describes an example of a step of press-molding using the apparatus of Figure 6A. First, as shown in FIG. 6A, placing the preform 301 between the upper mold 11 and the lower mold 12. Next, as shown in FIG. 6B, the slide die 14 toward lower die 12 is slid, to restrain the two first portions 301a by the lower mold 12 (lower mold body 12a) and a slide mold 14 (step (i)). Thus the first portion 301a is formed in the vertical wall 111. In this state, the second portion 301b and the surplus portion 301c may freely deformed.
[0081]
　Next, in a state in which the restraining a first portion 301a, as shown in FIG. 6C, lowers the upper die 11, thereby pressing the second portion 301b by the lower die 12 and upper die 11, the upper pressing the surplus portion 301c by the mold 11 and the slide mold 14. Thereby forming a press-formed product 100 (step (ii)). At that time, the second portion 301b is sandwiched between the pads 12b and the upper mold 11, and reaches the upper surface of the lower die body 12a is lowered as it is. Thus, the top plate portion 112 is formed. Surplus portion 301c is gradually bent in contact with the upper mold 11 and the slide mold 14 with the lowering of the upper die 11 becomes double. Thus, having the overlapping portion, the projecting portion 115 which projects obliquely downward is formed. In this manner, press-molded article 100 having a protruding portion 115 is obtained.
[0082]
　When performing the second step by hot stamping, the preform 301 which is heated is cooled in the press forming, and press forming and quenching are performed.
[0083]
　Protrusions 115 of the press-molded product 100 protrudes obliquely downward. Therefore, before returning the slide die 14 to the original position, it is preferable to move the press-molded product 100 upward. Specifically First, as shown in FIG. 6D, after the step (ii), by raising the upper die 11 and pad 12b with releasing the restraint of the vertical wall 111 by a lower mold 12 and the slide mold 14 increases the press-formed product 100 (step (iii)). At this time, the lower end of the projecting portion 115 (tip 115t) is to be located above the upper end of the slide 14 to raise the press-formed product 100. Releasing the restraint of the vertical wall portion 111 may be performed by separating slightly from the lower die 12 to slide die 14.
[0084]
　Next, as shown in FIG. 6E, release after step (iii) the slide 14 from the lower mold 12 (step (iv)). For example, as shown in FIG. 6E, the slide die 14 on the outer side than the tip portion 115t of the projecting portion 115 to be positioned, by sliding the sliding mold 14. Then, take out the press molded article 100 from the press apparatus.
[0085]
　When forming the press-molded product having a flange portion, may be formed flange portion by further pressing the press-molded product 100 obtained in the above step (third step). An example of a method of forming the flange portion, shown in FIGS. 7A and 7B.
[0086]
　Pressing apparatus shown in FIG. 7A, includes a upper die 21, lower die 22, and the attitude holding die 23. Upper mold 21 includes convex portions 21a, the recess 21b, the pad 21c, and a telescopic mechanism 21d. Pad 21c is connected to the concave portion 21b by a telescopic extension mechanism 21d.
[0087]
　First, as shown in FIG. 7A, placing the press-formed product 100 to press. Postural type 23 is intended to prevent that the press-molded product 100 is tilted, it does not restrict the press molded product 100. Then, lowering the upper die 21. With the descent of the upper die 21, first, the portion of the vertical wall portion 111 is secured by the pad 21c and the lower mold 22. When lowering the upper die 21 Furthermore, the expansion mechanism 21d is shortened, bent third portion 301d continuing from the vertical wall portion 111. In this way, one flange portion 113 is formed. By also other flange portion is formed in the same manner, the press-molded product having two flange portions (P) is obtained.
[0088]
　When producing a structural member of the present embodiment (S), the press-formed article obtained by the process described above (P), the other member (M) may be fixed in any manner.
Example
[0089]
　The present invention will be described in more detail by examples.
[0090]
　In an embodiment, the structural member using a press-molded product (P) 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).
[0091]
　The cross section of Sample 1 used in the simulation as a comparative example is schematically shown in Figure 8A. Sample 1 shown in Figure 8A, consists of two U-shaped members 31 and 32. Each U-shaped member 31 and 32, and two vertical wall portions and the top plate portion connecting them. As shown in FIG. 8A, the U-shaped member 31 and the U-shaped member 32 was assumed to be spot welded at the fixing portion 33 of the vertical wall portion. Of the size of each part samples 1, shown in Figure 8A. Incidentally, longitudinal length of the sample 1 was 800 mm.
[0092]
　The cross-sectional view of the sample 2 used in the simulation as a reference example 1, schematically shown in FIG. 8B. Sample 2 shown in FIG. 8B, the press-molded product 100a, cross-section and a member 210 of the U-shape. Incidentally, in the press-molded product 100a shown in FIG. 8B, the angle X is 180 °. Therefore, press-molded product 100a shown in FIG. 8B is not the press-molded product (P) according to the present embodiment. Press-molded product 100a includes a protrusion 115. The press molded product 100a and the member 210 was assumed to have been spot welded in a fixed portion 211 of the vertical wall portion 111. The shape of the sample 2 is as follows.
And angle X: 180 °
, angle Y (see FIG. 2): 90 °
- vertical wall height Hb1: 60 mm
Length of-protrusion D: 15 mm
between-two vertical wall portions of the distance (the top plate width) Wb1: 50 mm
height-member 210 Hb2: 15 mm
radius of curvature at the corner portion Ra and Rb: 5 mm
, longitudinal length: 800 mm
[0093]
　Samples of this embodiment using the simulation, the angle X of the projecting portion 115 of the sample 2 of Reference Example 1 shown in FIG. 8B, 202 °, 225 °, is obtained by changing the 247 °, and 270 °. Angle X is 202 °, 225 °, 247 °, and 270 ° of the cross section of the protrusion near the sample, respectively, 8C, 8D, FIG. 8E, and FIG. 8F.
[0094]
　The cross section of Sample 3 used in the simulation as a reference example 2, schematically shown in FIG. 8G. In the sample 3 shown in FIG. 8G, and the steel sheet is folded in triplicate at the upper end of the vertical wall portion 111, the portion corresponding to the projecting portion 115 is in close contact with the vertical wall portion 111. In other words, the portion corresponding to the projecting portion 115 is substantially not protrude from the boundary portion connecting the vertical wall portion 111 and the top plate portion 112. In Sample 3, the other shape was the same as the shape of the sample 2.
[0095]
　All samples, tensile strength at a thickness of 1.4mm is assumed to be made of a steel plate is 1500 MPa. The press-molded product with another member, is assumed to have fixed spot welding at a pitch of 40 mm.
[0096]
　The three-point bending test method used in the simulation is shown schematically in FIG. Three-point bending test, placing the sample into two pivot 1, it was carried out by pressing the samples from upward by impactor 2. The distance S between the two pivot 1 was 400mm or 700 mm. The radius of curvature of the fulcrum 1 was set to 50mm. The radius of curvature of the impactor 2 was 150mm. Collision speed of the impactor 2 was 7.2km / h. Note that the simulation was performed in consideration of the spot welding and material fracture.
[0097]
　The three-point bending test was collision impactor 2 from each sample of the upper (top plate side). A collision direction of the impactor 2, shown by arrows in FIGS. 8A and 8B.
[0098]
　The simulation results of three-point bending test are shown in FIGS. 10 to 13. 10 and 11 show the simulation results of Comparative Example (Sample 1) and sample of the invention Example (angle X = 270 °). Figure 10 is the distance S represents the result of the case of 700 mm, FIG. 11 shows the results when the distance S is 400 mm. The horizontal axis of FIG. 10 and 11 show impactor 2 amount of movement of the impactor 2 from colliding in the sample (amount of displacement). The vertical axis of FIG. 10 and 11 show a load generated in the impactor 2.
[0099]
　The 12 and 13, Comparative Example (Sample 1), Example 1 (Sample 2), the present invention embodiment (angle X = 202 °, 225 °, 247 °, and 270 °), and Reference Example 2 (Sample 3) shows the simulation results for. The vertical axis of FIG. 12 is an energy absorption amount until the amount of displacement reaches 60 mm. Figure 13 shows the maximum load occurring in the impactor 2. Both 12 and 13, the distance S represents the results for 700 mm.
[0100]
　As shown in FIGS. 12 and 13, when the distance S is 700 mm, the sample of the present invention example, Comparative Example (Sample 1), compared to Reference Example 1 (Sample 2) and Reference Example 2 (Sample 3) Characteristics it was high.
[0101]
　In particular, the characteristics of the comparative example (Sample 1) and Reference Example 2 (Sample 3) were significantly lower. The vertical wall portion of the sample 1 (Comparative Example) when the distance S is the amount of displacement at 700mm is 30mm had fallen outwardly. Similarly, the vertical wall portion of the sample 3 (Example 2) was also lying on the outside. On the other hand, the distance S is vertical wall part of the sample (angle X = 270 °) of the present invention examples of when the displacement amount in 700mm of 30mm had fallen inward. Although at present not clear, the characteristics of the sample of the present invention embodiment is high, it is possible that due to the vertical wall portion collapses inward.
[0102]
　As shown in the above embodiments, according to this embodiment, characteristics of the three-point bending test is high structural member obtained. By using the structural member of the present embodiment, or to improve the collision safety of automobiles, it is possible or weight of the motor vehicle.
Industrial Applicability
[0103]
　The present invention can be utilized press-molded product, and using the structural member for an automobile, and the method for producing a press-molded product.
DESCRIPTION OF SYMBOLS
[0104]
　10: press die
　11: upper die (press
　type) 12: lower mold (press
　type) 100: press-formed product
　101 or 101a, 101b: steel
　111: longitudinal wall portion
　112: the top plate portion
　113: flange portion
　114: corner
　115: protruding portion
　115 d: superimposition unit
　200: structure member
　210: other member
　301: preform
　301c: surplus portion
　X: angle between superimposed with the top plate portion

The scope of the claims

[Requested item 1]A press-formed article formed from a sheet of steel plate,
　and two vertical wall portions,
　and a top plate connecting the two vertical wall portions,
　two boundary connecting said top plate portion and the vertical wall portion wherein the at least one protrusion protruding from at least one of the boundary portion of the part,
　in the projecting portion, and the steel sheet and the steel sheet extending from said vertical wall portion extending from said top plate portion, the projecting portion of which protrudes from the boundary portion as superimposed at least a tip in overlapping portions,
　the protruding portion is present in at least part of the length of the press-
　the superposition between the top plate angle is greater than 180 ° formed between the part, the press molded product.
[Requested item 2]
　It includes two of said projection projecting from each of the two boundary portions, press-molded article according to claim 1.
[Requested item 3]
　Wherein the angle formed between the overlapping portions and the top plate is 180 ° greater than 270 ° or less, according to claim 1 or press molded article according to 2.
[Requested item 4]
　The tensile strength of the steel sheet is not less than 340 MPa, a press molded article according to any one of claims 1 to 3.
[Requested item 5]
　Wherein comprising two flanges extending from the ends of the two vertical wall portions, the press molded article according to any one of claims 1-4.
[Requested item 6]
　And a press molded article according to any one of claims 1 to 5, a structural member for a motor vehicle comprising the other member,
　so that said other member and the press-molded product constitutes a closed cross section on the other member is fixed to the press-structural members for automobiles.
[Requested item 7]
　A method of press-molded product produced according to any one of claims 1 to 4,
　including a second portion serving as the two becomes the vertical wall portion 2 of the first portion and the top plate portion the preform includes a first step of forming by deforming the steel sheet,
　by press-molding the preform, and a second step of forming the press-molded product,
　the preform, It includes a surplus portion for forming the projecting portion,
　in the second step to form the overlapping portions by overlapping at least a portion of the steel sheet forming the surplus portion of the press-molded product manufacturing Method.
[Requested item 8]
　The material tensile strength of the steel sheet is not less than 590 MPa, the second step is performed by a hot stamping method of press-molded product produced according to claim 7.
[Requested item 9]
　The second step, the lower mold, the upper mold, and is carried out using a press die including a slide type movable horizontally toward said lower mold,
　the second step, the said lower mold slide and the step of constraining the two first portions by the type (i),
　wherein in a state that restrains the two first portions, pressing said second portion by said lower die and upper die wherein the upper mold and said sliding mold and a step (ii) of forming the press-molded product by pressing the excess portion, the method of the press-molded product produced according to claim 7 or 8 together.
[Requested item 10]
　The lower mold includes a lower mold body, through a telescopic mechanism and a pad connected to said lower mold body,
　after the step (ii), with releasing the restriction by said sliding die and the lower die by raising the upper die and the pad, the step (iii) to increase the press-
　including after the step (iii), the step (iv) separating the slide die from the lower die, the method of press-molded product produced according to claim 9.
[Requested item 11]
　The press molded product includes two flange portions extending from the ends of the two vertical wall portions,
　after said second step, a third step of forming the flange portion, according to claim 9 or 10 the method of of the press-molded product manufacturing.