[0001]The present invention is particularly suitable structure member for an automobile, and a method for producing the same.
BACKGROUND
[0002]As the structure of the A Piraroa in recent years the automobile to protect the cabin, have been made many reinforcing suggestions by internal reinforcement.
[0003]Patent Document 1, the reinforcement of the internal A Piraroa, thickening the plate thickness of the vehicle front side, discloses a technique for improving the strength against a load inputted from the front.
[0004]
　However, the thick-walled site by reinforcement is only the front, not in consideration of to the load entering to the side sill. In the technique of Patent Document 1, although A-pillar front is resistant to the applied load, the load entering the receives a large load side sill is increased, without the A-pillar front is efficiently deformed, A-pillar only side sills are joined to the side surface is subjected to large deformation. In addition, weight reduction can not be expected.
[0005]
　Patent Document 2, by devising the structure of the reinforcement of the internal A-pillar, when the front wheel is moved at the time of collision, the traveling direction of the front wheels is varied in the form of A Piraroa suppress the entry of the front wheels to the cabin It discloses a technique.
[0006]
　The technique of Patent Document 2, the front wheels are oriented in the traveling direction, the front wheels of the width to be effective only if it is not too large than the vehicle width direction of A Piraroa. And if the front wheels are oriented in an oblique direction, when the front wheel width is wide, it is necessary to receive the load in a wide surface, the effect can not be expected.
CITATION
Patent Document
[0007]
Patent Document 1: JP 2011-37291 JP
Patent Document 2: JP 2013-141928 Patent Publication
Patent Document 3: WO 2011/145679
Summary of the Invention
Problems that the Invention is to Solve
[0008]
　At the time of a collision of the vehicle, not necessarily the wheels come jump into the cabin in the direction of travel and on the same axis. Therefore, the portion away from the A Piraroa, ie, reinforcement of the dash side is required. Preparation for such a case, it may dash cross is connected to the A-pillar lower inner. Dash cross is bonded to the A-pillar lower inner launch the flange. Therefore, when receiving the displaced dash cross, there is a problem that the junction is easily peeled off.
[0009]
　In order to solve the above problems, integrally molded A-pillar has a joint in the dash cross direction, further comprising a joint in the side sill direction, a structure having a three-dimensional three-pronged shape capable load transmission it is conceivable to use as the a-pillar lower inner.
[0010]
　More specifically, as shown in FIG. 1, a substantially L-shaped top plate (11), the protruding portion is a stretch flange extending upward on the top plate (12), a concave top plate parts outer edge containing (13) the vertical wall portion along the outer edge portion bent from (14) downwardly (15), substantially L-shaped lower flange portion extending from the vertical wall portion to the outside comprising a (16) structure it can be used. Such structures can be produced by stretch flangeability and free bending method, the protruding portions by stretch flanging (12), the vertical wall portion by free bending method (15), is possible to form the lower flange section (16) it can.
[0011]
　Free bending method is disclosed, for example, in Patent Document 3. The invention described in Patent Document 3, L-shaped as in the member, the blank parts having a bent portion in cross section vertical wall portion is convex to the top plate portion side in a plan view in a substantially hat shape (molding material) it is a method of molding from.
[0012]
　More specifically, the blank disposed between the die tool and pad and bending tool, (1) pressure through a pad part of the portion corresponding to the top plate portion of the blank as out-of-plane deformation suppressing region state, and, in the state the end of the portion corresponding to the lower side of the blank of the L-shaped is in a top plate on the same plane, by relatively moving the bending die and the die mold in a vertical direction, the blank slide (plane moving) on ​​the portion corresponding to the top plate portion of the die mold the ends of the portion corresponding to the lower side of the L-shaped, L by molding the vertical wall portion and a flange portion it is to mold the shape parts.
[0013]
　Or, (2) the pad to the portion of the portion corresponding to the top plate portion of the blank as out-of-plane deformation suppressing region close to or in contact, the gap between the pad and the die mold, blank thickness or more blanks of plate the thickness state was maintained at 1.1 times or less of, and, in the state the end of the portion corresponding to the lower side of the blank of the L-shaped is in a top plate on the same plane, the vertical bending type and the die mold by relative movement direction, while the ends of the portion corresponding to the lower side of the blank of the L-shaped slide (plane moving) on ​​the portion corresponding to the top plate portion of the blank out of the die mold, vertical by forming the wall portion and the flange portion, it is intended to mold the L-shaped shaped parts.
[0014]
　Forming method using the stretch flangeability and the free bending method is an excellent method to produce a structure having a three-dimensional three-pronged shape. However, for example, there is a case or when the vertical wall portion and a lower flange portion of the boundary radius of curvature is small, the expansion of the upper arm of the cross-sectional shape, such as the extension of the arm length, the severe form of molding is required more. In such a case, it is necessary to achieve further improvement of the moldability.
[0015]
　In general, when molding the stretch flange as in FIG. 1, occurs site where tensile strain is concentrated at the ends of the stretch flange, reduction in thickness tends to occur at the site, as a result, cracks It occurs more easily. This problem is particularly likely to occur when the tensile strength is molded structures with a high-tensile steel plate of more than 980 MPa. When molding by free bending method the lower flange shown in FIG. 1, a decrease in thickness at the boundary of the lower flange and the vertical wall portion is likely to occur.
[0016]
　The present invention was made in view of the above circumstances, an object of the present invention to provide a improved allowed structure and a manufacturing method thereof moldability.
Means for Solving the Problems
[0017]
　The present inventors have intensively studied a method for improving the moldability of a structure having a three-dimensional three-pronged shape. As a result, 1 second vertical wall portion (12) molded into step eye, then the first vertical wall portion 2 step eyes (15), and the first flange portion structure for molding (16) in the manufacturing method, the following findings were obtained. More specifically, when manufacturing the second vertical wall portion (12), portions of the blank to be the first flange portion 2 step eyes (16), preferably the first flange portion (16) first 1 of the vertical wall portion (15) portions of the blank to be near the boundary of, in, by not inhibit the deformation in the plane of the steel sheet, reduction in the thickness of the end portion of the second vertical wall portion (12), and it found that in two steps first it is possible to reduce the decrease in the thickness of the first flange portion.
[0018]
　The present invention is based on the above findings, which has been made to promote further studies, its gist the following.
[0019]
　(1) Tensile strength is a structure that is integrally molded product using the above steel sheet 590 MPa, the structure in plan view, the top plate including at least one recess in the outer edge portion, the top plate first vertical wall portion extending bent from some or all of the outer edge portion including the concave portion of the section, a first flange portion extending bent from the opposite side edges and the top plate portion of the first vertical wall portion, and a second vertical wall portion extending bent from an outer edge different from the edge comprising said recessed portion of said top plate, at least the top plate, the first vertical wall portion, or a first flange portion on structure characterized by having a One of the projections.
[0020]
　(2) the structure, the tensile strength is characterized in that it is a integrally molded product using the above steel sheet 980MPa structure (1).
[0021]
　(3) the thickness of the structure, the structure of the (1) or (2), which is a 0.6 ~ 1.8 mm.
[0022]
　(4) and the radius of curvature R of the concave portion, the height h of the first vertical wall portion, said to satisfy the 0.6 ≦ R / h ≦ 3.0 (1) ~ (3 any of the structures).
[0023]
　(5) In addition, any of the, characterized in that it comprises a second flange portion extending bent from the opposite side edges and the top plate portion of the second vertical wall portion (1) to (4) Structure body.
[0024]
　(6) the (1) to (4) The method of any of manufacturing structure, the manufacturing method described above, the molding material is a flat plate, it is placed between the die and the blank holder, the punch and the relative movement the step of forming the second vertical wall portion by which the molding material is pressurized deformed, and the molding material in which the second vertical wall portion is formed, is disposed between the die and the blank holder by , a step of forming a first vertical wall portion and the first flange portion by causing pressurized deformation to the molding material by moving the punch relative, used in the step of forming the second vertical wall portion the die or the blank holder, the manufacturing method of a structure and a space in at least part of the position in contact with the molding material in the pressurization is provided.
[0025]
　(7) said space, pressing method (6), characterized in that it the material is provided comprising a position that most flowing when forming the second vertical wall portion.
[0026]
　(8) said first vertical wall portion and the first flange portion and the molding material in which the second vertical wall portion is formed is disposed between the die and the blank holder, the molding material by moving the punch relative pressurized by deforming method of the structure of the (6) or (7), characterized in that it comprises the step of arranging the shape of the second vertical wall portion.
[0027]
　(9) A method for producing a structure according to the above (5), the manufacturing method described above, the molding material is a flat plate, is placed between the die and the blank holder, the molding by moving the punch relative the step of forming the second vertical wall portion and the second flange portion by causing pressurized deformation to the material, and the molding material in which the second vertical wall portion is formed, located between the die and the blank holder and, a step of forming a first vertical wall portion and the first flange portion by causing pressurized deformation to the molding material by moving the punch relative, the second vertical wall portion and a second flange is the die or the blank holder used in the step of forming the parts, a manufacturing method of a structure and a space in at least part of the position in contact with the molding material in the pressurization is provided.
[0028]
　(10) the space, pressing the (9), characterized in that it the material is provided comprising a position that most flowing when forming the second vertical wall portion and the second flange portion Method.
[0029]
　(11) the first vertical wall portion and the first flange portion and the molding material in which the second vertical wall portion and the second flange portion is formed is disposed between the die and the blank holder, the punch and the relative movement by pressurizing deform the molding material by, according to (9) or (10), characterized in that it comprises the step of arranging the second vertical wall portion and the shape of the second flange portion method of manufacturing the structure.
Effect of the invention
[0030]
　According to the present invention, in the manufacturing method of a structure having a three-dimensional three-pronged shape that is severe form of moldability, it is possible to improve the moldability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031]
Is a diagram showing an example of a structure having the Figure 1] three-dimensional three-pronged shape.
It is a diagram showing an outline of the first step of the method for manufacturing the structure of the present invention; FIG.
3 is a diagram showing the movement of the material for forming the second vertical wall portion in the blank.
4 is a diagram showing an outline of the second step of the method for manufacturing the structure of the present invention.
5 is a diagram showing an example of a sheet thickness reduction rate of the structure produced by the production method of the present invention.
6 is a diagram showing an example of a sheet thickness reduction rate of the structure produced by the production method not using the free buckling.
7 is a diagram showing another outline of the first step of the method for manufacturing the structure of the present invention.
8 is a diagram showing an example of a structure having four or flanges.
DESCRIPTION OF THE INVENTION
[0032]
　Hereinafter, a method for manufacturing the structure of the present invention.
[0033]
　Method of manufacture of the present invention includes a punch and a die, the blank is press-molded by a press molding apparatus having a pad restraining pressing a blank (molding material) such as a metal plate to punching, stretch flangeability, and it can be prepared by free bending method.
[0034]
　As a first step, forming a second vertical wall portion (12) by stretch flangeability. More specifically, as shown in FIG. 2, the blank (21) punched and (22) using a die (23), formed the second vertical wall portion (12). Blank holder (24) is suppressed blank (21) together with the die (23) to adjust the flow of material, also prevents the occurrence of wrinkles. Blank holder (24), there may be a gap not necessarily need to be in close contact with the blank (21). In the press molding method of the present invention, the blank holder (24) is not completely covered the blank (21), the space for flowing the material (25) is provided.
[0035]
　First, sandwich blank (21) between the die (23) and blank holder (24). Then in the punch (22) and relatively moving the die (23), formed the second vertical wall portion pressurizes the blank (21) to (12). At this time, the position of the punch corresponding to the space (25) of the blank holder (24) (22) also shaped so as not to interfere with the deformation of the blank (21).
[0036]
　In the example shown in FIG. 2, the second vertical wall portion forms a concave bend line on the blank (21), the bending line is formed such that the outer peripheral portion of the top plate portion. At the upper end center of the second vertical wall portion, a tensile strain is concentrated around the strain in the tangential direction of the upper end portion of the second vertical wall portion (blank (outer edges and a part of 21)) , compressive stress is generated at its minimum principal strain direction (generally normal direction at the upper end center of the second vertical wall portion). Here, the upper end center, the upper end of the substantial center not mean, first vertical wall portion to be formed later (15) and the second vertical wall portion close to the R portion of the first flange portion It means parts. For such compressive stress, the portion of the space (25) of the blank holder (24), not constrained blank (21) in the thickness direction, inducing the deformation of the plane of the blank (21) can do. Below, such a free out-of-plane deformation of "free buckling".
[0037]
　In the example of FIG. 2, when forming the top plate and the second vertical wall portion blank (21) under pressure, since the space (25) is provided, the upper end portion of the second vertical wall portion material is likely to flow into the center of the radial direction. As a result, the material inflow from the upper end portion of the second longitudinal wall is increased, the strain concentration at the upper end center of the second vertical wall portion is suppressed, the plate of the upper end portion of the second vertical wall portion a reduction in the thickness can be suppressed.
[0038]
　FIG. 3 shows the movement of the material for forming the second vertical wall portion in the blank, (a) shows the case where no space is formed in the blank holder, is (b) the space in the blank holder it is an example of the case being formed. As shown in (b) of the present invention, since the space is provided in the blank holder, it can be seen that the material inflow into the upper end portion of the second vertical wall portion is large.
[0039]
　The free buckling induced by providing the space (25), the compression deformation is relaxed, in the direction of the line length increases. As a result, projections deformed into the space (25) direction of the plane part of the molded body after molding occurs. In the production method of the present invention, the position where the protrusion occurs, the site is preferred, the first flange portion (16) first the first flange portion (16) is formed in the second step described below become a site where the boundary of the vertical wall portion (15) is formed is more preferable. The reason is that, when molding by free bending method the first flange portion, the thickness near the boundary of the first flange portion first vertical wall portion is for the most reduced easily.
[0040]
　Shape and size of the space (25) is not limited in particular, it is possible to obtain the effect of the present invention be provided on the portion of the material is intended for meat increase flow. The deformation in the plane is the point of the present invention effectively induced, and, considering the function for pressing the blank (21) of the blank holder (24), that the width 60 ~ 200 mm approximately slit-shaped good.
[0041]
　It followed in a second step, forming the first vertical wall portion (15) and the first flange portion (16). More specifically, as shown in FIG. 4, the blank (31), using a punch (32) of the die (34) to form a flange. Pad (33) to grip against the blank (31) to the punch (32). By pressing the die (34) fixed blank (31), the blank to form a first vertical wall portion along the outer edge (15) and the first flange portion (16) at the same time.
[0042]
　At this time, as described above, in the first step, portions to be the first flange portion in the second step (16), preferably a first vertical wall portion first flange portion (16) (15) since the site where the boundary protrusions are formed, a decrease in plate thickness at the site prone to reduction in thickness by the free bending method is reduced.
[0043]
　Figure 5 is a diagram showing an example of a sheet thickness reduction rate of the structure produced by the production method of the present invention. 6 is a thickness reduction rate of the structure produced by the manufacturing method that does not cause the free buckling.
[0044]
　From the results of FIGS. 5 and 6, according to the production method of the present invention, it is possible to reduce the sheet thickness reduction rate.
[0045]
　In the first step, it may be formed a second flange portion extending bent from the second vertical wall portion. In a first step, it shows a schematic of a case of forming the second vertical wall portion and the second flange portion in FIG. When compared with the example shown in FIG. 2, it is different in the shape of the die (71) and punch (74), by pressurizing the blank (72), together with the second vertical wall portion, the second longitudinal the second flange portion extending bent from the wall portion.
[0046]
　Following the second step, the first vertical wall portion (15) and the first flange portion (16) and the molding material in which the second vertical wall portion (12) is formed between the die and the blank holder arrangement, and by moving the punch relative, it may comprise a restriking step of arranging a shape of the second vertical wall portion (12).
[0047]
　According to the manufacturing method of the structure of the present invention described above, by performing processing by using a general press, a structure having a three-dimensional three-pronged shape that is severe form of moldability, specialized equipment without, it can be produced in a short working time. In particular, cracks are likely to occur during processing, it is effective for the production of structures with high-strength steel sheet.
[0048]
　In the above example the flange is set to trifurcated, it is also possible to similarly form four or flanges. Four or flanges, for example, the top plate portion and the substantially T-shaped, vertical wall portion along two outer edges of a substantially L-shape, and a flange provided around the T-shaped intersection of the top plate it can be a shape having a projecting portion is a flange extending in the.
[0049]
　Figure 8 shows an example of a four or flanges. Example of FIG. 8, two concave portions 82a at the outer edge in a plan view, a top plate portion 81 including a 82b, a first vertical wall portion 83a extending bent concave portion 82a, from 82b respectively, 83 b, a first vertical the second vertical wall portion extending bent wall portion 83a, a top plate portion of the 83b first flange portion 84a extending bent respectively from the opposite side edge, 84b, and a different edge outer portion including the recessed portion of the top plate It is equipped with a 85.
[0050]
　Thus, the punch, by changing the shape of the die is not limited to the example of the joint described above, it is clear that can produce structures of various shapes, also included in the present invention those modifications is it is needless to say.
[0051]
　As the molding material, thickness 0.6 ~ 1.8 mm, preferably at 0.6 ~ 1.2 mm, although higher tensile strength 980MPa high strength steel sheet is suitable, depending on the application, other steel plate , aluminum alloy plate, it can also be used a resin composite material flat plate such as FRP.
[0052]
　Further, in the structure, the curvature R, and the height h of the first vertical wall portion when viewed from the top of the top plate is not particularly limited. However, when using the method disclosed in the present invention, be in the form of R / h 0.6 to 3.0, it is capable of forming a molding failure is reduced structure, R / h is 0 .8 to 2.7 is more preferable.
Example
[0053]
　Using various materials, it created a structure having a three-pronged structure shown in FIG. Blank is made of a material shown in the material column in the invention examples shown in Table 1, sandwiching the blank having a thickness shown in plate thickness column, between the die (23) and blank holder (24) shown in FIG. 2, a punch (22) and die (23) relative to each to form a second vertical wall portion. In the comparative example, with reference to that there is no space (25) to the blank holder (24) to form a second vertical wall portion as well.
[0054]
　Then, the blank pad (33) shown in FIG. 4 gripped against the punch (32), by pressing the fixed blank-die (34), a first vertical wall portion along the outer edge and the second 1 of the flange was formed at the same time.
[0055]
　The molding results are shown in Table 1. Molding results in the table, "A" what was moldable, "B" which necking has occurred in the second vertical wall portion, "C" cracking the second vertical wall portion has occurred It means a thing. Further, R in Table curvature when viewed from the top of the top plate, h denotes the height of the first vertical wall portion (see FIG. 1).
[0056]
　According to the present invention, the type of material, thickness, regardless of the shape, it was confirmed that it is possible to mold structure having a trifurcated structure.
[0057]
[Table 1]

[0058]
[Table 2]

DESCRIPTION OF SYMBOLS
[0059]
　11 the flat plate portion
　12 and the second vertical wall portion
　13 recessed portion
　14 outer portion
　15 the first vertical wall portion
　16 first flange portion
　21 the blank
　22 punched
　23 die
　24 blank holder
　25 spaces
　31 blank
　32 punched
　33 pads
　34 Die
　71 Die
　72 blank
　73 blank holder
　74 punch
　81 top plate portion
　82a, 82b concave portion
　83a, 83 b first vertical wall portion
　84a, 84b first flange portion
　85 the second vertical wall portion

WE CLAIM

Tensile strength is a structure that is integrally molded product using the above steel sheet 590 MPa,
　the structure,
　in plan view, the top plate including at least one recess in the outer edge portion,
　of the top plate above first vertical wall portion extending bent from some or all of the outer edge portion including a concave portion,
　a first flange portion extending bent from the opposite side edges and the top plate portion of the first vertical wall portion, and
　the top the second vertical wall portion extending bent from an outer edge different from the edge comprising said recessed portion of the plate portion
comprises a,
　the top plate, at least one protrusion first vertical wall portion, or a first flange portion on having a
structure characterized by.
[Requested item 2]
　Wherein the structure The structure of claim 1 in which the tensile strength is characterized in that the integrally molded product using the above steel sheet 980 MPa.
[Requested item 3]
　The plate thickness of the structure, the structure according to claim 1 or 2, characterized in that a 0.6 ~ 1.8 mm.
[Requested item 4]
　And the curvature radius R of the concave portion, the height h of the first vertical wall portion, claim 1 any one of 3, characterized in that satisfy 0.6 ≦ R / h ≦ 3.0 structure according to.
[Requested item 5]
　Furthermore, the structure according to any one of claims 1 to 4, characterized in that it comprises a second flange portion extending bent from the opposite side edges and the top plate portion of the second vertical wall portion.
[Requested item 6]
　A method of manufacturing a structure according to any one of claims 1 to 4,
　the manufacturing method described above,
　which is a flat plate shaped material, arranged between the die and the blank holder, to move the punch relative the step of forming the second vertical wall portion by which the molding material is pressurized deformed, and by
　the molding material in which the second vertical wall portion is formed, is disposed between the die and the blank holder, the punch and by relatively moving forming a first vertical wall portion and the first flange portion by causing pressurized deformation to the molding material
comprises a,
　the die used in the step of forming the second vertical wall portion or blank holder, the space on at least part of the position in contact with the molding material in the pressurization is provided
a manufacturing method of a structure characterized by.
[Requested item 7]
　The space is press-forming method according to claim 6, characterized in that the material is provided comprising a position that most flowing when forming the second vertical wall portion.
[Requested item 8]
　The molding material of the first vertical wall portion and the first flange portion and the second vertical wall portion is formed is disposed between the die and the blank holder, pressurized to the molding material by moving the punch relative by deforming, method of manufacturing the structure according to claim 6 or 7, characterized in that it comprises the step of arranging the shape of the second vertical wall portion.
[Requested item 9]
　A method of manufacturing a structure according to claim 5,
　the manufacturing method described above,
　the molding material is a flat plate, is placed between the die and the blank holder, pressurized to the molding material by moving the punch relative step by deforming to form the second vertical wall portion and a second flange portion, and
　the molding material in which the second vertical wall portion is formed, is disposed between the die and the blank holder, a punch by relatively moving forming a first vertical wall portion and the first flange portion by causing pressurized deformation to the molding material
comprises a,
　to form the second vertical wall portion and the second flange portion the die or the blank holder used in the process, the space on at least part of the position in contact with the molding material in the pressurization is provided
a manufacturing method of a structure characterized by.
[Requested item 10]
　The space is press-forming method according to claim 9, characterized in that the material is provided comprising a position that most flowing when forming the second vertical wall portion and the second flange portion.
[Requested item 11]
　The molding material of the first vertical wall portion and the first flange portion and the second vertical wall portion and the second flange portion is formed is disposed between the die and the blank holder, by moving the punch relative by pressurizing deform the molding material, method of manufacturing the structure according to claim 9 or 10, characterized in that it comprises the step of arranging the second vertical wall portion and the shape of the second flange portion.