Specification
Title of invention: Hot stamp molded product, manufacturing method and manufacturing apparatus thereof
Technical field
[0001]
　The present invention relates to a hot stamp molded product, a manufacturing method thereof, and a manufacturing apparatus thereof.
Background technology
[0002]
　In order to improve the fuel efficiency by reducing the weight of the automobile body and the collision safety of the automobile body, the strength of the steel sheet forming the automobile body has been promoted.
[0003]
　FIG. 36 is a perspective view showing an example of an A-pillar lower outer panel 1 which is a component on the body side of a body shell of an automobile. As shown in FIG. 36, the A-pillar lower outer panel 1 has a corner portion 2 on its upper portion. The corner portion 2 has a vertical wall 3 that is vertical to the vehicle front-rear direction and a vertical wall 4 that is substantially vertical to the vehicle vertical direction.
[0004]
　An outward flange 3a for overlapping and joining the A pillar lower inner panel 5 is provided on the edge of the vertical wall 3 that is perpendicular to the vehicle front-rear direction. On the other hand, since the vertical wall 4 that is substantially vertical to the vehicle up-down direction serves as a windshield mounting surface, no outward flange is provided at the edge of the vertical wall 4 and is formed only by the vertical wall 4. In the present specification, the vertical wall 4 is also referred to as "glass surface flange".
[0005]
　FIG. 37( a) and FIG. 37( b) are explanatory views showing a conventional two-step cold forming method of the A pillar lower outer panel 1.
[0006]
　Conventionally, as shown in FIG. 37(a), after outwardly forming flanges 3a, 4a on each of the two vertical walls 3, 4 in the corner portion 2 in the first step, as shown in FIG. 37(b). In the second step, the A-pillar lower outer panel 1 is cold formed in two steps by bending back the outward flange 4a of the vertical wall 4 that is substantially vertical to the vehicle vertical direction.
[0007]
　However, there is an antinomy relationship between high strength (for example, tensile strength of 1200 MPa or more) and formability of a steel sheet, and a higher strength A pillar lower having two vertical walls 3 and 4 without causing cracks or wrinkles. It is difficult to manufacture the outer panel 1. Moreover, since the molding is performed in two steps, the manufacturing cost increases.
[0008]
　In recent years, a steel blank, which is a forming material for the A-pillar lower outer panel 1, is heated to a temperature of Ac 3 or higher and then formed by a press die, and the hot stamping method in which heat is taken out is applied to the corner portion 2. A higher strength A-pillar lower outer panel 1 having two vertical walls 3, 4 is to be manufactured.
[0009]
　FIG. 38 shows a cold-molded A pillar lower outer panel 1 having vertical walls 3 and 4 at a corner portion 2 based on the press molding method for a door inner panel having a surplus portion disclosed in Patent Document 1, for example. It is an explanatory view showing a situation in which drawing is performed in one step by a hot stamping method. FIG. 39 is an explanatory view showing the vicinity of a corner portion of the molded A pillar lower outer panel 1 before trimming.
[0010]
　As shown in FIGS. 38 and 39, in the press molding method of a door inner panel having a surplus portion, the blank portion 9 is provided with the die 6, the punch 7 and the blank holder 8 to perform draw forming. Then, the excess thickness portion 60, which is an unnecessary portion except for the product-shaped portion, is cut along a trim line 61 shown by a broken line in FIG. 39 to mold the A pillar lower outer panel 1 in one step. In particular, when a press-molded product is manufactured by the hot stamping method, it is necessary to mold it in one step as much as possible from the viewpoint of manufacturing cost.
[0011]
　However, in this press forming method, the forming depth of the A-pillar lower outer panel 1 is inevitably deep because the extra thickness portion 60 is provided. For this reason, it is difficult to manufacture the A-pillar lower outer panel 1 having a small corner radius of curvature and the A-pillar lower outer panel 1 having a small bending radius of curvature, which is difficult to form.
[0012]
　Further, when drawing is performed in the hot stamping method, the portion of the blank 9 sandwiched between the die 6 and the blank holder 8 that is formed on the flange adjacent to the holding portion 9a is rapidly cooled at the initial stage of hot stamping. The material transfer to the part formed into the vertical walls 3 and 4 is hindered. Therefore, cracks occur early in the ridgelines 3b and 4b following the vertical walls 3 and 4 in FIG. For example, the plate thickness reduction rate at the meeting portion of the ridgelines 3b and 4b reaches 26%. Therefore, the radii of curvature of the ridgelines 3b and 4b cannot be reduced.
[0013]
　FIG. 40 is an explanatory view showing a situation where the A pillar lower outer panel 1 having the vertical walls 3 and 4 in the corner portion 2 is bent and formed in one step by cold forming or hot stamping. 41(a) is an explanatory view showing the vicinity of the corner portion 2 of the bent and formed A pillar lower outer panel 1, and FIG. 41(b) is an illustration showing a cutout portion 64 provided in the vicinity of the corner portion 2A. It is explanatory drawing which shows the pillar lower outer panel 1.
[0014]
　As shown in FIGS. 40 and 41, the die 6, the punch 7 and the pad 62 are used to press the pad pressing portion 63 with the pad 62 to bend and form the blank 9, whereby the A pillar lower outer panel 1 is formed in one step. It can be molded.
[0015]
　However, since the corner portion 2 shrinks and deforms due to flange, when the A pillar lower outer panel 1 is bent and formed in one step, excessive wrinkles (overlapping wrinkles in some cases) occur on the vertical wall 4 of the corner portion 2. In the invention of Patent Document 2, it is attempted to suppress the generation of wrinkles in the corner portion or the like by drawing one side of the corner portion.
[0016]
However, the plate thickness reduction rate of the vertical wall 4 of the corner portion 2 reaches, for example, 25%.
Therefore, when the A-pillar lower outer panel 1 is manufactured by bending by the hot stamping method, as shown in FIG. Inevitably, the A-pillar lower outer panel 1 having a desired shape cannot be manufactured.
[0017]
　Patent Document 3 discloses a technique of suppressing cracks and wrinkles of a steel sheet by using a servo die cushion. Further, Patent Document 4 discloses a technique of defining a mold structure that controls the clearance between the upper and lower molds during molding and suppressing cracks and wrinkles.
[0018]
　The servo die cushion used by the invention disclosed in Patent Document 3 is not only expensive, but its control is complicated. Therefore, in the invention disclosed in Patent Document 3, it is not possible to suppress cracks and wrinkles inexpensively and easily.
[0019]
　Further, even if the die used in the invention disclosed in Patent Document 4 controls the clearance between the die and the punch holding the flange, the wrinkle cannot be completely suppressed.
[0020]
　As described above, according to the conventional technique, the A-pillar lower outer panel having a tensile strength of 1200 MPa or more could not be formed by the hot stamping method without cracks or wrinkles in one step.
Prior art documents
Patent literature
[0021]
Patent Document 1: JP-A-2005-212533 ​​JP
Patent Document 2: JP-A 2012-24837 JP
Patent Document 3: JP-A 2011-50971 JP
Patent Document 4: JP-A 2011-147970 Publication
Summary of the invention
Problems to be Solved by the Invention
[0022]
　The present invention has been made in view of the above problems related to the prior art, and is a hot stamp molded product having high collision characteristics and rigidity while having a thin plate thickness and light weight, and such hot stamp molding. An object of the present invention is to provide a method and an apparatus for manufacturing a hot stamp molded product capable of manufacturing a product.
Means for solving the problem
[0023]
(1) A hot stamped article according to an aspect of the present invention has at least one of a tensile strength of 1200 MPa or more and a martensitic steel structure, and extends from one end to the other end in the longitudinal direction. A steel hot stamped product having a first part, a corner part and a second part, which are continuous in order, wherein each of the first part, the corner part and the second part is a cross section perpendicular to the longitudinal direction. And a vertical plate connected to the vertical plate; the second portion has a first outward flange adjacent to the vertical wall; and the corner portion, A vertical flange extending from the vertical wall of the first portion, a second outward flange adjacent to a vertical wall located on the outer peripheral side of the corner portion of the two vertical walls, the vertical flange and the first flange. 2 and a transition portion in which the outward flanges are connected to each other;
[0024]
According to the hot stamp molded product having the above structure, in the corner portion of the hot stamp molded product having at least one of the tensile strength of 1200 MPa or more and the martensitic steel structure, the transition portion where the vertical flange and the second outward flange are continuous. By having the above, it is possible to provide a hot stamp molded product having high impact characteristics and rigidity while having a thin plate thickness and a light weight.
[0025]
　(2) In the hot stamp molded article according to (1) above, an A pillar lower outer panel may be used.
[0026]
　(3) A method of manufacturing a hot stamp molded product according to an aspect of the present invention is a method of press molding a blank by a hot stamp method to manufacture the hot stamp molded product according to (1) or (2) above. A blank is placed between a punch and a blank holder, a die arranged to face the blank holder, and a bending die, and a portion of the blank formed in the top plate is cut by the punch. In the blank, at least a part of a part of the two vertical walls of the first part and the corner part that is formed on the vertical wall located on the outer peripheral side of the corner part is supported by the blank holder and the blank holder. While sandwiched by a die, the die and the bending die are relatively brought close to the punch, and at least a part of the portion formed on the vertical wall is drawn by the punch, the blank holder and the die. The remaining portion excluding the portion to be drawn is bent by the punch and the bending die.
[0027]
According to the method for manufacturing a hot stamp molded product having the above-described structure, in manufacturing a hot stamp molded product having at least one of a tensile strength of 1200 MPa or more and a martensitic steel structure, the vertical flange and the second outward facing direction are provided at the corners. It is possible to manufacture a hot stamp molded product having a transition portion that is continuous with the flange. The hot stamped product has high impact characteristics and rigidity while having a thin plate thickness and a light weight.
[0028]
　(4) In the method for manufacturing a hot stamped product according to (3) above, at least a part of the blank formed on the vertical wall and the vertical flange located on the outer peripheral side of the corner portion of the blank, It may be configured such that the drawing is performed before reaching the molding bottom dead center, and the sandwiching by the blank holder and the die is completed.
[0029]
　(5) In the method for manufacturing a hot stamp molded product according to (3) or (4) above, a pad that is arranged so as to face the punch is further provided, and a portion of the blank formed in the top plate is formed. It may be configured to be sandwiched by the punch and the pad.
[0030]
　(6) In the method for manufacturing a hot stamped product according to any one of (3) to (5) above, both the die and the blank holder are in the first part and the corner part in the blank. A first surface that abuts and sandwiches a portion of the two vertical walls that is formed on the vertical wall located on the outer peripheral side of the corner portion, a bent portion that is continuous with the first surface, and is continuous with the bent portion. And a second surface inclined with respect to the first surface in a direction away from the bending die, the second surface of each of the die and the blank holder being bent by the punch and the bending die. The blank may be formed by drawing.
[0031]
　(7) In the method for producing a hot stamp molded product according to (6) above, in the blank in the middle of molding, an end of a portion of each of the die and the blank holder constrained by the second surface, and the punch. Also, the difference in the pressing direction from the end of the portion that becomes the first outward flange by being bent by the bending die may be configured to be 20 mm or less.
[0032]
　(8) In the method for manufacturing a hot stamped product according to (6) or (7) above, the bent portion of the die is provided at a height position near a height position of a bending ridge line portion of the bending die. The bent portion of the blank holder may be provided at a height position near the height position of the punch shoulder R portion of the punch.
[0033]
　(9) In the method for manufacturing a hot stamp molded product according to any one of (6) to (8), the inclination angle of the second surface with respect to the first surface of the blank holder is (punch shoulder of the punch). The inclination angle of the R portion may be equal to or greater than −30 degrees and may be less than or equal to the inclination angle of the punch shoulder R portion of the punch +30 degrees.
[0034]
　(10) In the method for manufacturing a hot stamp molded product according to any one of (6) to (9), the first surface of the blank holder is when the blank is sandwiched by the die and the blank holder. The punch may be configured to exist at a height position that substantially matches the height position of the punch bottom surface of the punch.
[0035]
　(11) In the method for manufacturing a hot stamp molded article according to any one of (6) to (10), the first surface of the die has a shape that, when the blank is sandwiched by the die and the blank holder, It may be configured so that it exists at a height position that substantially matches the height position of the surface of the bending die on which the bending ridge line portion exists.
[0036]
(12) In the apparatus for manufacturing a hot stamp molded product according to one aspect of the present invention, the blank is press-molded by the hot stamp method to manufacture the hot stamp molded product according to (1) or (2) above. And a punch and a blank holder, a die arranged to face the blank holder, and a bending die, and the die and the bending die and the punch can relatively approach and separate from each other. And the punch is capable of supporting a portion of the blank that is formed on the top plate, and the blank holder and the die are the two portions of the first portion and the corner portion of the blank. It is possible to sandwich at least a part of a portion of the two vertical walls that is formed on the outer peripheral side of the corner portion, and the punch, the blank holder, and the die are the outer periphery of the corner portion. At least a part of the portion formed on the vertical wall located on the side can be draw-formed, and the punch and the bending die can bend-form the remaining portion except the draw-formed portion. Characterize.
[0037]
By using the apparatus for manufacturing a hot stamped product having the above-described configuration, the vertical flange and the second outward flange are continuous at the corner portion, which has at least one of a tensile strength of 1200 MPa or more and a martensitic steel structure. It is possible to produce hot stamped moldings having transitions. The hot stamped product has high impact characteristics and rigidity while having a thin plate thickness and a light weight.
[0038]
　(13) In the manufacturing apparatus for a hot stamped product according to (12), the blank holder and the die include the corner portion of the two vertical walls of the first portion and the corner portion of the blank. The sandwiching of at least a part of the portion formed on the vertical wall located on the outer peripheral side of the may be finished by drawing out before reaching the forming bottom dead center.
[0039]
　(14) The hot stamp molded article manufacturing apparatus according to (12) or (13), further including a pad arranged to face the punch, wherein the punch and the pad are the tops of the blank. It may be configured so as to sandwich the portion to be molded into the plate.
[0040]
　(15) In the manufacturing apparatus for a hot stamped product according to any one of (12) to (14), the die and the blank holder are both at the first part and at the corner part in the blank. A first surface that abuts and sandwiches a portion of the two vertical walls that is formed on the vertical wall located on the outer peripheral side of the corner portion, a bent portion that is continuous with the first surface, and is continuous with the bent portion. In addition, it may be configured to have a second surface that is inclined with respect to the first surface in a direction away from the bending die.
[0041]
　(16) In the manufacturing apparatus for a hot stamped product according to (15) above, the bending portion of the die is provided at a height position near a height position of a bending ridge line portion of the bending die, and The bent portion of the blank holder may be configured to be provided at a height position near the height position of the punch shoulder R portion of the punch.
[0042]
　(17) In the manufacturing apparatus for a hot stamped product according to (15) or (16), the inclination angle of the second surface with respect to the first surface of the blank holder may be (the punch shoulder R portion of the punch). The inclination angle may be −30 degrees) or more and (the inclination angle of the punch shoulder R portion of the punch +30 degrees) or less.
[0043]
　(18) In the manufacturing apparatus for a hot stamped product according to any one of (15) to (17), the first surface of the blank holder is when the blank is sandwiched by the die and the blank holder. The punch may be configured to exist at a height position that substantially matches the height position of the punch bottom surface.
[0044]
　(19) In the manufacturing apparatus for a hot stamped product according to any one of (15) to (18), the first surface of the die has a shape that, when the blank is sandwiched by the die and the blank holder, It may be configured so that it exists at a height position that substantially matches the height position of the surface of the bending die on which the bending ridge line portion exists.
Effect of the invention
[0045]
　According to the invention of the present application, it is possible to provide a hot stamp molded product having high impact characteristics and rigidity while having a thin plate thickness and a light weight. Further, according to the present invention, it is possible to provide a hot stamp molded article manufacturing method and manufacturing apparatus capable of manufacturing a hot stamp molded article having high impact characteristics and rigidity while having a thin plate thickness and a light weight.
Brief description of the drawings
[0046]
FIG. 1 is a schematic perspective view for explaining a configuration in the vicinity of a corner portion of an A pillar lower outer panel that is a hot stamp molded product according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view for explaining a cross section perpendicular to the longitudinal direction in each part of the A pillar lower outer panel that is the hot stamp molded product according to the embodiment of the present invention. 2A is a sectional view of the first portion, FIG. 2B is a sectional view of a corner portion, and FIG. 2C is a sectional view of the second portion.
FIG. 3 is a schematic view of the vicinity of a corner portion of the A pillar lower outer panel when viewed in a plan view from a direction perpendicular to the plate surface of the top plate of the A pillar lower outer panel.
FIG. 4 is a schematic perspective view for explaining a corner portion of an A pillar lower outer panel that is a hot stamp molded product according to the first embodiment.
FIG. 5 is a schematic perspective view for explaining a modified example of the corner portion of the A pillar lower outer panel that is the hot stamp molded product according to the first embodiment.
FIG. 6 is a schematic perspective view for explaining a modified example of the corner portion of the A pillar lower outer panel which is the hot stamp molded product according to the first embodiment.
FIG. 7 is a schematic perspective view for explaining a modified example of the corner portion of the A pillar lower outer panel which is the hot stamp molded product according to the first embodiment.
FIG. 8 is a schematic perspective view for explaining a modified example of the corner portion of the A pillar lower outer panel which is the hot stamp molded product according to the first embodiment.
FIG. 9 is a schematic perspective view for explaining a modified example of the corner portion of the A pillar lower outer panel which is the hot stamp molded product according to the first embodiment.
FIG. 10 is a schematic perspective view for explaining a modified example of a corner portion of a conventional A-pillar lower outer panel.
FIG. 11 is a schematic perspective view for explaining a modified example of a corner portion of a conventional A-pillar lower outer panel.
FIG. 12 is a schematic perspective view for explaining a modified example of a corner portion of a conventional A-pillar lower outer panel.
FIG. 13 is a schematic perspective view for explaining a modified example of the corner portion of the conventional A pillar lower outer panel.
FIG. 14 is a schematic perspective view for explaining a modified example of the corner portion of the conventional A pillar lower outer panel.
FIG. 15 is a photograph of a metal structure of a hot stamp molded product obtained by hot stamping.
FIG. 16 is a schematic perspective view for explaining a structural member in which the A pillar lower outer panel according to the first embodiment and an inner member are joined.
FIG. 17 is a schematic perspective view for explaining an apparatus for manufacturing a hot stamp molded product according to the embodiment of the present invention.
FIG. 18 illustrates a situation in which the A-pillar lower outer panel of the first embodiment is manufactured by performing one-step bending and drawing composite molding, which is a combination of bending and drawing, using the hot stamping method. FIG.
FIG. 19 is a schematic perspective view for explaining the outer shape of a punch used in the hot stamping method.
FIG. 20 is a schematic perspective view for explaining a deformed state of a blank during molding by the manufacturing apparatus of the first embodiment.
FIG. 21 is a diagram illustrating movements of a die and a blank holder in respective cross sections of a first part, a corner part, and a second part of an A pillar lower outer panel during molding by the manufacturing apparatus of the first embodiment, FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
FIG. 22 is a diagram illustrating the movement of the die and the blank holder in each cross section of the first part, the corner part, and the second part of the A pillar lower outer panel during molding by the manufacturing apparatus of the first embodiment, FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
FIG. 23 is a diagram illustrating movements of a die and a blank holder in respective cross sections of a first part, a corner part, and a second part of the A pillar lower outer panel during molding by the manufacturing apparatus of the first embodiment. FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
FIG. 24 is a diagram illustrating movements of a die and a blank holder in respective cross sections of a first part, a corner part, and a second part of an A pillar lower outer panel during molding by the manufacturing apparatus of the first embodiment, FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
FIG. 25 is a schematic perspective view for explaining the manufacturing apparatus according to the second embodiment.
FIG. 26 is a schematic diagram for explaining an initial die arrangement of the manufacturing apparatus of the second embodiment viewed from the direction A in FIG. 25.
FIG. 27 is a schematic perspective view for explaining a deformed state of a blank during molding by the manufacturing apparatus of the second embodiment.
FIG. 28 is a diagram illustrating movements of a die and a blank holder in respective cross sections of a first part, a corner part, and a second part of the A pillar lower outer panel during molding by the manufacturing apparatus of the second embodiment. FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
FIG. 29 is a diagram illustrating movements of a die and a blank holder in respective cross sections of a first part, a corner part, and a second part of the A pillar lower outer panel during molding by the manufacturing apparatus according to the second embodiment. FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
FIG. 30 is a diagram illustrating movements of a die and a blank holder in respective cross sections of a first portion, a corner portion, and a second portion of the A pillar lower outer panel during molding by the manufacturing apparatus according to the second embodiment. FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
[FIG. 31] FIG. 31 is a view showing movements of a die and a blank holder in respective cross sections of a portion serving as a first portion, a corner portion, and a second portion of an A pillar lower outer panel during molding by the manufacturing apparatus of the second embodiment, FIG. 6 is a schematic cross-sectional view for explaining the deformation behavior of the blank.
FIG. 32 is a schematic perspective view in the vicinity of a corner portion of the A pillar lower outer panel, for explaining the evaluation target of the collision analysis.
FIG. 33 is a schematic perspective view for explaining a collision characteristic evaluation method.
FIG. 34 is a schematic perspective view for explaining the rigidity evaluation method.
FIG. 35 is a schematic perspective view in the vicinity of a corner portion of an A pillar lower outer panel according to Experimental Example 2.
FIG. 36 is a perspective view showing an example of a conventional technique of an A-pillar lower outer panel, which is a component on the body side of a body shell of an automobile.
[FIG. 37] FIG. 37 is an explanatory diagram showing a conventional two-step cold forming method for an A-pillar lower outer panel.
[FIG. 38] FIG. 38 is an explanatory view showing a situation where an A pillar lower outer panel having a vertical wall at a corner portion is formed in one step by cold forming or hot stamping.
[FIG. 39] FIG. 39 is an explanatory view showing the vicinity of a corner portion of the molded A pillar lower outer panel before trimming.
[FIG. 40] FIG. 40 is an explanatory view showing a situation where an A pillar lower outer panel having a vertical wall at a corner is bent and formed in one step by cold forming or hot stamping.
41(a) is an explanatory view showing the vicinity of a corner portion 2 of an A pillar lower outer panel formed by bending, and FIG. 41(b) is an illustration showing a cutout portion provided in the vicinity of the corner portion. It is explanatory drawing which shows a pillar lower outer panel.
MODE FOR CARRYING OUT THE INVENTION
[0047]
　As described above, when a blank is formed into the above-mentioned hot stamped product by the hot stamping method, when the blanking is performed, it is cracked early at the ridge lines 3b and 4b following the vertical walls 3 and 4 at the corners shown in FIG. On the other hand, when bending is performed, excessive wrinkles (or overlapping wrinkles in some cases) occur on the vertical wall 4 of the corner portion 2 shown in FIG.
[0048]
　The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, have completed the present invention by obtaining the following new findings (A) to (D).
　(A) Excessive wrinkling occurs when bending is performed For forming the vertical wall 4 of the corner portion 2 shown in FIG. 41(a), the material inflow amount can be controlled by performing drawing using a blank holder. The wrinkles can be prevented.
[0049]
　(B) Excessive wrinkling occurs when bending is performed For forming a portion other than the vertical wall 4 of the corner portion 2 shown in FIG. It is possible to promote the material transfer from the portion formed on the flange to the portion formed on the vertical wall 4, and prevent the occurrence of cracks.
[0050]
　(C) That is, by using the bending and drawing composite molding in which the bending and the drawing are combined, the blank can be formed in one step by the hot stamping method.
[0051]
　(D) Formability can be further improved by devising the shapes of the die and the blank holder used for drawing.
[0052]
　Hereinafter, various embodiments of the present invention will be described with reference to the drawings, but it is obvious that the present invention is not limited to these embodiments.
[0053]
　In the present invention, the "locking mechanism" is a case where a pad is used and a flange formed by drawing is sandwiched by a blank holder and a die at a molding bottom dead center, that is, a state in which it is sandwiched by upper and lower molds. You will need it. The locking mechanism is a mechanism to mechanically or electrically control (lock) the blank holder from rising when the die rises after the bottom dead center of molding with the pad pressing the top plate of the molded product. is there.
[0054]
[Embodiment 1]
　Hereinafter, a hot stamp molded product, a manufacturing method thereof, and a manufacturing apparatus thereof according to the present embodiment will be sequentially described with reference to the accompanying drawings. In the following description, the case where the hot stamp molded product is the A pillar lower outer panel is taken as an example, but the present invention is not limited to the A pillar lower outer panel, and is similarly applied to the front side member, for example. ..
[0055]
　The front side member has a bent portion that goes up from the bottom of the floor to the dash panel and protrudes to the front, and is bent in an S shape. The floor of the front side member and the portion joined to the dash panel have a flange, and the bent portion protruding to the front does not have a flange.
[0056]
(1-1) Hot Stamp Molded Product
　The hot stamp molded product according to the present embodiment has at least one of a tensile strength of 1200 MPa or more and a martensitic steel structure and has one end to the other end in the longitudinal direction. It is a hot stamped product made of steel having a first part, a corner part and a second part, which are sequentially connected to each other.
[0057]
In this hot stamped product, each of the first part, the corner part and the second part has a top plate and two vertical walls connected to the top plate when viewed in a cross section perpendicular to the longitudinal direction. , The second part has a first outward flange adjacent the vertical wall.
Further, the corner portion has a vertical flange extending from the vertical wall of the first portion, a second outward flange adjacent to the vertical wall located on the outer peripheral side of the corner portion of the two vertical walls, the vertical flange and the first vertical flange. 2 a transition portion in which the outward flanges are continuous with each other.
[0058]
FIG. 1 is a schematic diagram for explaining a configuration near a corner portion of an A pillar lower outer panel 10 that is a hot stamp molded product according to the present invention.
[0059]
　As shown in FIG. 1, the A-pillar lower outer panel 10 includes a first portion 11 and a corner portion 12 in order from one end (not shown) to the other end (not shown) in the longitudinal direction. And a second part 13.
[0060]
　Each of the first portion 11, the corner portion 12, and the second portion 13 has a shape including a top plate 14 and two vertical walls 15 connected to the top plate 14 when viewed in a cross section perpendicular to the longitudinal direction. Have.
[0061]
　The second portion 13 has a first outward flange 16 adjacent to the vertical wall 15.
[0062]
　The corner portion 12 bends in a direction intersecting with the two vertical walls 15. That is, the corner portion 12 bends in the direction in which the second portion 13 exists in a plan view seen from the direction perpendicular to the plate surface of the top plate 14.
[0063]
As shown in FIG. 1, the corner portion 12 may be defined as a portion located on the outer peripheral side of the corner portion and including a portion where the ridgeline formed by the top plate 14 and the vertical wall 15 is a curve.
For example, as shown in FIG. 3, the corner portion 12 has a ridgeline formed by the top plate 14 and the vertical wall 15 when the A pillar lower outer panel 10 is viewed in a plan view from a direction perpendicular to the plate surface of the top plate 14. It may be a portion that includes a curved portion and is surrounded by a line segment (dotted line in FIG. 3) perpendicular to the ridgeline formed by the top plate 14 and the vertical wall 15.
[0064]
　The corner portion 12 has a vertical flange 17 extending from the vertical wall 15 of the first portion 11 and a second outward flange 18 adjacent to the vertical wall 15 of the two vertical walls 15 located on the outer peripheral side of the corner portion 12. Have and. The vertical flange 17 is substantially parallel to the vertical wall 15 of the first part 11 (the vertical wall 15 of the two vertical walls 15 located on the outer peripheral side of the corner) and is connected to the vertical wall 15 of the first part 11. May be configured as. The second outward flange 18 is substantially parallel to the first outward flange 16 of the second portion 13, and is configured to connect to the first outward flange 16 of the second portion 13.
The vertical wall 15 of the corner portion 12 (the vertical wall 15 of the two vertical walls 15 located on the outer peripheral side of the corner portion) has a curved surface, and the vertical wall 15 of the first portion 11 and the vertical wall of the second portion 13 are provided. Connect to 15.
[0065]
The corner portion 12 has a transition portion 19 in which the vertical flange 17 and the second outward flange 18 are continuous. As will be described later, the transition portion 19 has a vertical flange 17, a second outward flange 18, and a vertical wall 15 at the corner (a vertical wall 15 located on the outer peripheral side of the corner of the two vertical walls 15), as will be described later. ) Is included.
The hatched portion in FIG. 1 is the vertical flange 17 and the second outward flange 18.
[0066]
FIG. 2 shows a cross-sectional view taken along the lines a to c shown in FIG. That is, FIG. 2A, FIG. 2B, and FIG. 2C are schematic views of the first portion 11, the second portion 13, and the corner portion 12 as viewed in a cross section perpendicular to the longitudinal direction. FIG.
[0067]
As shown in FIG. 2A, the first portion 11 has a top plate 14 and two vertical walls 15 connected to the top plate 14 when viewed in a cross section perpendicular to the longitudinal direction. The vertical wall 15 located on the inner peripheral side of the corner portion 12 has a third outward flange 20 adjacent to the vertical wall 15.
[0068]
As shown in FIG. 2C, the second portion 13 has a top plate 14 and two vertical walls 15 connected to the top plate 14 when viewed in a cross section perpendicular to the longitudinal direction. The vertical wall 15 located on the outer peripheral side of the corner portion 12 has a first outward flange 16 adjacent to the vertical wall 15, and the vertical wall 15 located on the inner peripheral side of the corner portion 12 includes the vertical wall 15 Has a third outwardly facing flange 20 adjacent thereto.
[0069]
As shown in FIG. 2B, the transition portion 19 of the corner portion 12 has a top plate 14 and two vertical walls 15 connected to the top plate 14 when viewed in a cross section perpendicular to the longitudinal direction. And has a vertical flange 17 extending from the vertical wall 15 of the first part, and a second outward flange 18 adjacent to the vertical wall 15 located on the outer peripheral side of the corner part 12 of the two vertical walls 15. The vertical flange 17 and the second outward flange 18 are connected.
Further, the vertical wall 15 located on the inner peripheral side of the corner portion 12 has a third outward flange 20 adjacent to the vertical wall 15.
[0070]
Here, the cross section perpendicular to the longitudinal direction of the corner portion 12 may be a cross section perpendicular to the longitudinal direction of either the first portion 11 or the second portion 13. Alternatively, the cross section of the corner portion 12 perpendicular to the longitudinal direction may be defined as a surface having the same angle with respect to the longitudinal direction of the first portion 11 and the longitudinal direction of the second portion 13.
[0071]
The vertical flange 17 and the second outward flange 18 of the corner portion 12 may have at least a portion having a width of 5 mm or more, preferably 15 mm or more.
Since the vertical flange 17 and the second outward flange 18 have a portion with a width of 5 mm or more, the A pillar lower outer panel 10 and the inner member can be joined by laser welding. Further, since the vertical flange 17 and the second outward flange 18 have a portion having a width of 15 mm or more, they can be joined by spot welding. The rigidity is improved by joining the A pillar lower outer panel 10 and the inner member.
[0072]
　4 to 9 show modified examples of the corner portion 12. The hatched portions in FIGS. 4 to 9 are the vertical flange 17 and the second outward flange 18.
　In the modified example of FIG. 4, the width of the vertical flange 17 of the corner portion 12 is narrow, and the end portion of the vertical flange 17 and the end portion of the vertical wall 15 of the first portion 11 have a step. Further, the width of the second outward flange 18 is narrow, and the end portion of the second outward flange 18 and the end portion of the first outward flange of the second portion 13 have a step.
[0073]
In the modified example of FIG. 5, the width of the vertical flange 17 of the corner portion 12 decreases as the distance from the first portion 11 increases.
This modification also has a transition portion 19 in which the vertical flange 17 and the second outward flange 18 are continuous.
[0074]
In the modified example of FIG. 6, the width of the vertical flange 17 of the corner portion 12 decreases as the distance from the first portion 11 increases. At the position farthest from the first portion 11, the vertical flange 17 has a width of 0, but has a transition portion 19 in which the vertical flange 17 and the second outward flange 18 are continuous.
[0075]
In the modification of FIG. 7, the width of the second outward flange 18 decreases as the distance from the second portion 13 increases.
This modification also has a transition portion 19 in which the vertical flange 17 and the second outward flange 18 are continuous.
[0076]
In the modification of FIG. 8, the width of the second outward flange 18 is narrow, and the end portion of the second outward flange 18 and the end portion of the first outward flange of the second portion 13 have a step.
This modification also has a transition portion 19 in which the vertical flange 17 and the second outward flange 18 are continuous.
[0077]
In the modification of FIG. 9, the width of the vertical flange 17 of the corner portion 12 is narrow, and the end portion of the vertical flange 17 and the end portion of the vertical wall 15 of the first portion 11 have a step. In addition, there is a portion where the vertical flange 17 does not exist at the end of the second outward flange 18.
This modification also has a transition portion 19 in which the vertical flange 17 and the second outward flange 18 are continuous.
[0078]
In the A-pillar lower outer panel 10 according to this embodiment, the top plate 14 that is a non-processed portion has a plate thickness of 0.7 to 2.0 mm. By setting the plate thickness of the top plate 14 in this range, the weight of the A pillar lower outer panel 10 can be reduced. In particular, the A-pillar lower outer panel 10 according to the present embodiment has the strength to be described later, so that it is possible to obtain the remarkable effect of reducing the weight while securing the collision characteristics.
[0079]
In the A-pillar lower outer panel 10 according to the present embodiment, the plate thickness of the vertical wall 15 in the first portion 11 is preferably 80 to 120% of the plate thickness of the non-processed portion. That is, when the plate thickness of the non-processed portion is in the range of 0.7 to 2.0 mm, the plate thickness of the vertical wall 15 in the first portion 11 is preferably 0.56 to 2.20 mm.
Further, in the A-pillar lower outer panel 10 according to the present embodiment, it is more preferable that the plate thickness of the vertical wall 15 in the first portion 11 is 90 to 110% of the plate thickness of the non-processed portion.
[0080]
In the A-pillar lower outer panel 10 according to the present embodiment, the plate thickness of the vertical wall 15 in the second portion 13 is preferably 80 to 120% of the plate thickness of the non-processed portion. That is, when the plate thickness of the unprocessed portion is in the range of 0.7 to 2.0 mm, the plate thickness of the vertical wall 15 in the second portion 13 is preferably 0.56 to 2.20 mm.
Furthermore, in the A-pillar lower outer panel 10 according to the present embodiment, the plate thickness of the vertical wall 15 in the second portion 13 is more preferably 90 to 110% of the plate thickness of the non-processed portion.
[0081]
Further, in the A pillar lower outer panel 10 according to the present embodiment, the plate thickness of the first outward flange 16 of the second portion 13 or the second outward flange 18 of the corner portion 12 is larger than that of the non-machined portion. It is preferably 80 to 120%. That is, when the plate thickness of the non-processed portion is in the range of 0.7 to 2.0 mm, the plate thickness of the first outward flange 16 or the second outward flange 18 is 0.56 to 2.20 mm. It is preferable.
Furthermore, in the A-pillar lower outer panel 10 according to the present embodiment, the plate thickness of the first outward flange 16 or the second outward flange 18 is 90 to 110% of the plate thickness of the unprocessed portion. Is more preferable.
[0082]
In the A-pillar lower outer panel 10 according to the present embodiment, it is preferable that the width of the vertical wall 15 of the first portion 11 is in the range of 40 to 100 mm in order to obtain desired rigidity. Further, it is preferable that the width of the vertical wall 15 of the second portion 13 is set in the range of 40 to 100 mm and the width of the second outward flange 18 of the second portion 13 is set to 5 to 30 mm.
Further, in order to further improve the collision characteristics, it is more preferable that the width of the vertical wall 15 of the first portion 11 is in the range of 60 to 100 mm and the width of the vertical wall 15 of the second portion 13 is in the range of 60 to 100 mm. .. Further, the width of the second outward flange 18 of the second portion 13 is more preferably 15 to 20 mm so that spot welding can be performed without waste.
[0083]
In the description of the above embodiment, the corner portion 12 of the A-pillar lower outer panel 10 has the transition portion, in other words, the corner portion 12 does not have a “cutout portion”.
[0084]
10 to 14 are examples of the A-pillar lower outer panel 21 having a notch 23 on the outer peripheral side of the corner portion 22. That is, this is a modification of the conventional A-pillar lower outer panel that requires the notch 23 in order to suppress the occurrence of wrinkles at the corners.
[0085]
In the example of FIGS. 10 and 11, the notch 23 is provided over the entire circumference of the corner 22 on the outer circumference side. In the example of FIGS. 12 to 14, a cutout portion 23 is provided in a part of the corner portion 22.
[0086]
　The A-pillar lower outer panel 10 according to the present embodiment has at least one of a tensile strength of 1200 MPa or more and a martensitic steel structure.
FIG. 15 is a photograph of the metallographic structure of the hot stamped product obtained by hot stamping, showing the martensitic steel structure.
[0087]
　As described above, the A pillar lower outer panel 10 that is the hot stamped product according to the present embodiment has at least one of tensile strength of 1200 MPa or more and a steel structure of martensite, and the corner portion 12 has the vertical flange 17. Since the second outward flange 18 is connected to the transition portion 19, the bending rigidity and the torsional rigidity are remarkably improved.
　Furthermore, the A-pillar lower outer panel 10 which is the hot stamp molded product according to the present embodiment is lightweight because it has a plate thickness of 0.7 to 2.0 mm.
[0088]
　FIG. 16 is an example of the structural member 26 in which the A pillar lower outer panel 10 according to the present embodiment and the inner member 25 are joined. As shown in FIG. 16, the A-pillar lower outer panel 10 has a first portion 11, a corner portion 12, and a second portion 13 in this order from one end 10a to the other end 10b in the longitudinal direction. The inner member 25 is joined to the A pillar lower outer panel 10 at the vertical flange 17 and the second outward flange 18.
[0089]
　The body shell incorporating the A-pillar lower outer panel 10 according to the present embodiment suppresses an increase in weight and, through the dash panel joined to the A-pillar lower outer panel 10, the engine compartment (particularly the left and right front side members). The rigidity in the vicinity of the attachment portion) can be increased, and thus, for example, the amount of bending of the front side member during traveling of the pylon slalom can be reduced, and the steering stability of the vehicle can be improved.
[0090]
(1-2) Manufacturing Apparatus
　Next, a manufacturing apparatus of the hot stamp molded product according to the present invention will be described.
[0091]
　FIG. 17 is a schematic perspective view for explaining the manufacturing apparatus 30 according to the present invention. In FIG. 17 and FIGS. 20, 25, and 27 described later, the work surface of each tool is extracted and shown in order to make the drawings easy to see.
[0092]
　The manufacturing apparatus 30 is an apparatus for manufacturing the A-pillar lower outer panel 10 by press-molding the blank 40 in one step by a hot stamping method. The manufacturing apparatus 30 includes a punch 31 and a blank holder 32, a pad (not shown) arranged to face the punch 31, a die 33 arranged to face the blank holder 32, and a bending die 34.
[0093]
　The pad may not necessarily be used and may be appropriately used as necessary. However, when the pad is not used, the blank 40 may be displaced in an unintended direction during molding, and cracks or wrinkles may occur. Requires.
[0094]
　The die 33, the bending die 34, and the punch 31 are arranged so as to be relatively close to and away from each other.
[0095]
　The punch 31 and the pad can hold down the portion of the blank 40 that is formed on the top plate 14.
[0096]
　The blank holder 32 and the die 33 sandwich the part of the two vertical walls 15 existing in the first portion 11 and the corner portion 12 of the blank 40, which is formed on the vertical wall 15 located on the outer peripheral side of the corner portion 12, between them. Is possible.
[0097]
　The punch 31, the blank holder 32, and the die 33 are at least a part of a portion of the two vertical walls 15 existing in the first portion 11 and the corner portion 12, which are formed on the vertical wall 15 located on the outer peripheral side of the corner portion 12. Can be formed by drawing, and the punch 31 and the bending die 34 can be formed by bending the remaining portion excluding this portion.
[0098]
　The blank holder 32 and the die 33 are used for forming the bottom dead end of the two vertical walls 15 present in the first portion 11 and the corner portion 12 on the portion to be molded on the vertical wall 15 located on the outer peripheral side of the corner portion 12. It ends by passing through before reaching the point.
[0099]
　The pad or blank holder 32 has a locking mechanism. The locking mechanism is for preventing damage to the press-molded product by pressurizing the press-molded product in which the blank holder 32 or the pad is molded together with the die 33 and the bending mold 34 when the mold is elevated after the bottom dead center of the molding. This is a mechanism that mechanically or electrically control (lock) the rise of the blank holder 32 when the die is raised after the bottom dead center of molding.
[0100]
　This locking mechanism is necessary when the pad is used and the flange of the draw forming part is sandwiched by the blank holder 32 and the die 33 at the bottom dead center of the forming.
[0101]
(1-3) Manufacturing Method
　Next, a method of manufacturing the hot stamp molded product according to the present invention will be described.
In the following description, the case of using the pad 35 will be described as an example.
[0102]
　FIG. 18 is a view for explaining a situation in which the A-pillar lower outer panel 10 according to the present embodiment is manufactured by performing one-step bending and drawing composite molding, which is a combination of bending and drawing, using the hot stamping method. It is a figure.
FIG. 19 is an explanatory diagram showing the outer shape of the punch 31 used in the manufacturing method according to the present embodiment.
[0103]
　In the manufacturing method according to the present embodiment, the blank 40 is press-molded by the hot stamping method to manufacture the A pillar lower outer panel 10.
[0104]
　As shown in FIG. 18, the blank 40 includes a punch 31 and a blank holder 32, a pad 35 arranged to face the punch 31, a die 33 arranged to face the blank holder 32, and a bending die 34. Place in between.
[0105]
　Next, the portion of the blank 40 to be formed on the top plate 14 (“pad pressing portion” in FIG. 18) is pressed by the punch 31 and the pad 35.
[0106]
　Next, as shown in FIG. 18, a portion of the blank 40 that is formed on the vertical wall 15 located on the outer peripheral side of the corner portion 12 (a portion described as “a region with a holder” in FIG. 18) is a blank holder 32. And the die 33. This portion is a portion formed on the vertical wall 15 of the first portion 11 of the A-pillar lower outer panel 10 (vertical wall 15 located on the outer peripheral side of the corner portion 12).
The “holder boundary” in FIG. 18 indicates the end position of the blank holder 32.
[0107]
　Then, the die 33 and the bending die 34 are brought relatively close to the punch 31, and the vertical wall 15 positioned on the outer peripheral side of the corner portion 12 of the two vertical walls 15 existing in the first portion 11 and the corner portion 12 is positioned. At least a part of the part to be formed is drawn by the punch 31, the blank holder 32 and the die 33. At the same time, the remaining portion (the meshed portion described as the “holderless region” in FIG. 18) excluding the portion to be drawn is bent by the punch 31 and the bending die 34.
[0108]
　Here, as shown in the section C in FIG. 18, when the die 33 and the bending die 34 simultaneously start contact with the blank 40 to start the forming, the excessive movement of the material during the forming is suppressed and wrinkles are not formed. It is desirable because it can reduce the occurrence.
[0109]
　Immediately before the completion of the molding, the portion of the blank 40 to be molded on the vertical wall 15 located on the outer peripheral side of the corner portion 12 is squeezed out before reaching the molding bottom dead center, and is formed by the blank holder 32 and the die 33. The pinching is complete.
[0110]
　That is, the vertical wall 15 of the first portion 11 having no flange is formed by drawing. When the vertical wall of the first part is drawn, the vertical wall 15 having no flange can be formed by performing so-called "drawing and drawing". In the drawing process, the blank is sandwiched between the die and the die holder during molding, and when the molding is completed, the blank is not sandwiched between the die and the die holder.
[0111]
In order to surely pull out the aperture, the aperture depth of the vertical wall 15 of the first portion 11 is preferably the height of the vertical wall 15+(10 to 20 mm), and the height of the vertical wall 15+(10 to 30 mm) is more preferable. Here, the drawing depth is the distance that the die 33 moves after blank holding. The amount of movement of the blank holder 32 may be (height of the vertical wall 15+(10 to 20 mm)).
　By forming the vertical wall 15 of the first portion 11 by drawing, the A-pillar lower outer panel 10 of the present embodiment can be formed by a one-step hot stamping method without a locking mechanism.
[0112]
　In this way, the A pillar lower outer panel 10 is molded in one step by the manufacturing method according to the present embodiment.
[0113]
　For example, when the molding is performed in two steps as shown in FIG. 37, a bend-back portion may occur especially when a blank having a strength of 980 MPa or more is used. In the A-pillar lower outer panel, since the vertical wall (glass surface flange) of the first portion having no outward flange serves as a mounting surface of the windshield, it is not preferable to have such a bent back portion. In particular, when the vertical wall has a curved shape instead of a straight shape, a bend-back portion tends to occur.
Since the vertical wall of the first part is formed by the one-step hot stamping method in the hot stamped product according to the present embodiment, such a bent back part may occur in the glass surface flange of the A pillar lower outer panel. Absent.
[0114]
　FIG. 20 is an enlarged perspective view showing a deformed state of the blank during molding by the manufacturing apparatus 30 of the first embodiment, and is a view seen from the direction D in FIG. 17. Note that, in FIG. 20, the die 33 and the bending die 34 are omitted for easy understanding of the drawing. Further, in FIG. 20, the pad 35 is shown on the blank 40.
[0115]
　Next, the movement of the die 33 and the blank holder 32 and the deformation behavior of the blank 40 in the manufacturing method according to this embodiment will be described.
[0116]
　21 to 24 show the movement of the die 33 and the blank holder 32 and the deformation behavior of the blank 40 in each cross section of the first portion 11, the corner portion 12 and the second portion 13 of the A pillar lower outer panel 10. It is a schematic sectional view for explaining.
[0117]
　21(a), 22(a), 23(a) and 24(a) shows a die in a cross section perpendicular to the longitudinal direction of a portion which is the first portion 11 of the A pillar lower outer panel 10. It is a figure showing movement of 33 and blank holder 32, and deformation behavior of blank 40.
[0118]
　21(b), 22(b), 23(b) and 24(b) show the die 33 in a cross section perpendicular to the longitudinal direction of the portion that becomes the corner portion 12 of the A pillar lower outer panel 10. It is a figure showing movement of blank holder 32 and deformation behavior of blank 40.
[0119]
　21(c), 22(c), 23(c), and 24(c) show bending in a cross section perpendicular to the longitudinal direction of a portion that becomes the second portion 13 of the A pillar lower outer panel 10. It is a figure showing movement of type 34 and deformation behavior of blank 40.
[0120]
　21 to 24, FIG. 21A, FIG. 21B, and FIG. 21C show the positional relationship in each cross section at the same time.
　21(a), 21(b) and 21(c) show a state in which the blank 40 is placed on the punch bottom surface 31b.
[0121]
Similarly, FIG. 22A, FIG. 22B, and FIG. 22C show the positional relationship in each cross section at the same time.
In FIG. 22A and FIG. 22B, the end portion of the blank 40 is sandwiched and deformed by the die 33 and the blank holder 32. In FIG. 22(c), the blank 40 is bent while its cross section remains straight.
[0122]
23(a), 23(b) and 23(c) show the positional relationship in each cross section at the same time.
[0123]
24(a), 24(b) and 24(c) show the positional relationship in each cross section at the same time.
In FIG. 24A, the end of the blank 40 is drawn out to form the vertical wall 15 and the vertical wall 15 having the third outward flange 20. In FIG. 24B, the vertical wall 15, the second outward flange 18 and the vertical flange 17 of the corner portion 12 are formed, and the vertical wall 15 having the vertical wall 15 and the third outward flange 20 is formed. .. In FIG. 24C, the vertical walls 15 each having the first outward flange 16 and the third outward flange 20 are formed.
[0124]
　In the manufacturing method according to the present embodiment, it is preferable that the conditions of hot pressing are heating at 900° C. (at least a temperature of Ac 3 points or higher) for 4 minutes. The cooling rate by the mold is preferably 30° C./s or more, and cooling pipes may be installed in the mold to achieve this cooling rate.
[0125]
　In the present embodiment, as the chemical components of the blank 40, the amount of C is 0.090 to 0.40% by mass, the amount of Mn is 1.0 to 5.0% by mass, and the amount of B is 0.00050 to 0.05% by mass. %, the strength of the hot stamped product can be secured.
[0126]
[Embodiment 2]
　Next, another embodiment of the apparatus and method for manufacturing a hot stamped product according to the present invention will be described.
　The hot stamp molded product manufactured by the manufacturing apparatus and the manufacturing method of the second embodiment may have the same configuration as the hot stamp molded product according to the first embodiment. Embodiment 2 below is the same as Embodiment 1 described above except for the configuration described below.
[0127]
(2-1) Manufacturing Device In
　the manufacturing device 30 of Embodiment 1, the holder working surface 32a where the blank holder 32 contacts the blank 40 and the die working surface where the die 33 contacts the blank 40 are both flat horizontal surfaces. Is.
As shown in FIG. 20, as the molding progresses, the deformation behavior of the restraint portion 40-1 restrained by the holder working surface 32 a and the die working surface of the blank 40 and the bending of the blank 40 by the punch 31 and the bending die 34. The deformation behavior of the molded bent portion 40-2 is different.
[0128]
With the manufacturing apparatus and the manufacturing method according to the second embodiment, the occurrence of cracks and wrinkles at the boundary portion 40-3 is suppressed regardless of the manufacturing conditions such as the strength and plate thickness of the blank 40 and the height of the vertical wall 15. be able to.
[0129]
　25: is explanatory drawing which shows the manufacturing apparatus 50 of Embodiment 2, FIG. 26 is explanatory drawing which shows the initial metal mold arrangement|positioning of the manufacturing apparatus 50 seen from the A direction in FIG. 25, and FIG. It is explanatory drawing which expands and shows the deformation state of the blank in the middle of shaping|molding by the manufacturing apparatus 50.
In the description of the second embodiment, parts of the manufacturing apparatus 50 that are different from the manufacturing apparatus 30 will be described, and portions common to the manufacturing apparatus 30 will be assigned the same reference numerals in the drawings, and redundant description will be omitted. Although the manufacturing apparatus 50 of the second embodiment uses the pad 35, the pad 35 may not be used.
[0130]
　The manufacturing apparatus 50 of the second embodiment aims to further suppress the occurrence of cracks and wrinkles at the boundary portion 40-3, and as shown in FIGS. 25 to 28, the die 53 includes a first surface 53a and a first surface 53a. The blank holder 52 has a first surface 52a, a bent portion 52b continuous with the first surface 52a, and a bent portion 53b continuous with the first surface 53a and a second surface 53c continuous with the bent portion 53b. The second surface 52c is continuous with the portion 52b.
[0131]
　The first surfaces 53a and 52a of the die 53 and the blank holder 52 are formed on the vertical wall 15 located on the outer peripheral side of the corner portion 12 of the two vertical walls 15 of the first portion 11 and the corner portion 12 of the blank 40. It abuts at least a part of the portion to be sandwiched.
[0132]
　The second surfaces 53c and 52c of the die 53 and the blank holder 52 are arranged to be inclined with respect to the first surfaces 53a and 52a in a direction away from the bending die 34.
[0133]
　As shown in FIG. 26, the bent portion 53 b of the die 53 is provided at a height position in the vicinity of the height position of the bending ridge line portion 34 a of the bending die 34, and the bent portion 52 b of the blank holder 52 is formed in the punch 31. It is desirable to provide the punch shoulder R portion 31a at a height position near the height position thereof in order to prevent cracks and wrinkles from occurring at the boundary portion 40-3.
[0134]
　As shown in FIG. 26, the inclination angle θ 1 of the second surface 52c with respect to the first surface 52a of the blank holder 52 is not less than ( the inclination angle θ 2 −30 degrees of the punch shoulder R portion 31a of the punch 31) and (punch 31 In order to prevent the occurrence of cracks and wrinkles at the boundary portion 40-3, it is preferable that the angle of inclination of the punch shoulder R portion 31a is θ 2 +30 degrees or less.
[0135]
　As shown in FIG. 26, the first surface 52a of the blank holder 52 may exist at a height position that substantially matches the height position of the punch bottom surface 31b of the punch 31 when the bending die 34 contacts the blank 40. It is desirable to prevent the occurrence of cracks and wrinkles at the boundary portion 40-3.
[0136]
　Further, as shown in FIG. 26, the first surface 53a of the die 53 has a height substantially equal to the height position of the surface of the bending die 34 where the bending ridge 34a exists when the die 53 contacts the blank 40. The presence at the position is desirable in order to prevent the occurrence of cracks and wrinkles at the boundary portion 40-3.
[0137]
　The manufacturing apparatus 50 is configured as described above.
[0138]
(2-2) Manufacturing Method In the
　manufacturing apparatus 50, the die 53 and the blank holder 52 are provided with the second surfaces 53c and 52c, respectively. Therefore, while the part of the blank 40 in the middle of forming constrained by the second surfaces 53c, 52c and the part of the blank 40 in the middle of forming which is bent and formed by the punch 31 and the bending die 34 similarly fall down, the punch 31, the die The draw forming by the 53 and the blank holder 52 and the bend forming by the punch 31 and the bending die 34 are performed.
[0139]
　Therefore, at the boundary portion 40-3, the restraint portion 40-1 restrained by the second surfaces 53c and 52c of the blank 40 being formed, and the punch 31 and the bending die 34 of the blank 40 being formed are bent and formed. No step is formed at the boundary portion 40-3 with the bent portion 40-2.
Here, "creating a step" means that a bent portion and a drawn portion in a range of 30 mm are sandwiched between the bent portion of the blank (bent portion) and the drawn portion of the blank (drawn portion), respectively. This means that the difference in the average position in the pressing direction between the portion and the portion exceeds a predetermined amount, for example, 20 mm.
[0140]
More specifically, in the blank 40 in the process of forming, the die 53 and the blank holder 52 are bent by the end portions of the portions constrained by the second surfaces 53c and 52c, and are punched by the punch 31 and the bending die 34. The difference in the pressing direction from the end of the portion that becomes the outward flange 16 may be 20 mm or less. More preferably, this difference is 15 mm or less, and further preferably 10 mm or less.
[0141]
Further, the difference between the end portions in the pressing direction may be 20 times or less, more preferably 15 times or less, and further preferably 10 times or less the plate thickness of the blank 40.
Here, the end portion and the end portion are defined as the end portion of the blank 40 at a position of 30 mm from the boundary between the bent portion (bent portion) of the blank and the drawn portion (drawn portion) of the blank. May be done.
[0142]
　Next, the movement of the die 53 and the blank holder 52 and the deformation behavior of the blank 40 in the manufacturing method according to the present embodiment will be described.
[0143]
　28 to 31 show the movement of the die 53 and the blank holder 52 and the deformation behavior of the blank 40 in each cross section of the first portion 11, the corner portion 12, and the second portion 13 of the A pillar lower outer panel 10. It is a figure for explaining.
[0144]
　28(a), 29(a), 30(a) and 31(a) show a die in a cross section perpendicular to the longitudinal direction of a portion which becomes the first portion 11 of the A pillar lower outer panel 10. It is a figure showing movement of 53 and blank holder 52, and deformation behavior of blank 40.
[0145]
　28(b), 29(b), 30(b), and 31(b) show the die 53 in a cross section perpendicular to the longitudinal direction of the corner portion 12 of the A pillar lower outer panel 10. It is a figure showing movement of blank holder 52 and deformation behavior of blank 40.
[0146]
　28(c), 29(c), 30(c), and 31(c) show bending in a cross section perpendicular to the longitudinal direction of a portion that becomes the second portion 13 of the A pillar lower outer panel 10. It is a figure showing movement of type 34 and deformation behavior of blank 40.
[0147]
　28 to 31, FIGS. 28A, 28B, and 28C show the positional relationship in each cross section at the same time.
　28A, 28B and 28C show a state in which the blank 40 is placed on the punch bottom surface 31b.
[0148]
29(a), 29(b) and 29(c) show the positional relationship in each cross section at the same time.
29(a) and 29(b), the end of the blank 40 is sandwiched and deformed by the die 53 and the blank holder 52. In FIG. 29(c), the blank 40 is bent while its cross section remains linear. Here, it can be seen that there is no difference between the position of the end portion of the blank 40 in FIG. 29(b) in the pressing direction and the position of the end portion of the blank 40 in FIG. 29(c) in the pressing direction.
[0149]
30(a), 30(b) and 30(c) show the positional relationship in each cross section at the same time. Even in this state, there is maintained a state in which there is no difference between the position in the pressing direction of the end of the blank 40 in FIG. 30(b) and the position in the pressing direction of the end of the blank 40 in FIG. 30(c). ing.
[0150]
31(a), 31(b) and 31(c) show the positional relationship in each cross section at the same time.
In FIG. 31A, the end portion of the blank 40 is drawn out to form the vertical wall 15 and the vertical wall 15 having the third outward flange 20. In FIG. 31B, the vertical wall 15, the second outward flange 18 and the vertical flange 17 of the corner portion 12 are formed, and the vertical wall 15 having the vertical wall 15 and the third outward flange 20 is formed. .. In FIG. 31C, the vertical wall 15 having the first outward flange 16 and the third outward flange 20 is formed.
[0151]
　According to the manufacturing method according to the second embodiment, for example, regardless of manufacturing conditions such as the strength and plate thickness of the blank 40, the height of the vertical wall 15, and the like, the A-pillar that is the hot stamp molded product illustrated in FIG. The lower outer panel 10 can be provided in one step without cracking or wrinkling.
[0152]
[Examples] Examples
　of the present invention will be described below.
[0153]
(Experimental Example 1)
　Evaluation of rigidity and collision characteristics of hot stamped products was performed by CAE (Computer Aided Engineering). Collision analysis and rigidity analysis were performed using a general-purpose FEM code L:S-DYNA ver971.
[0154]
　32A, that is, two types of A-pillar lower outer panels having different plate thickness reduction rates in a portion close to the top plate of the vertical wall located on the outer peripheral side of the corner portion in the corner portion as the evaluation target of the collision analysis. Was prepared (Example 1 and Comparative Example 1).
[0155]
The width of the vertical flange of the A pillar lower outer panel of Example 1 was 20 mm, and the width of the second outward flange was 20 mm. In Example 1, the plate thickness reduction rate at the corner portion (A portion in FIG. 32) was set to 10%. Each flange width of the A-pillar lower outer panel of Comparative Example 1 was the same as that of Example 1, but the reduction rate of the plate thickness at the corner portion was 26%.
The plate thickness distribution of these A-pillar lower outer panels was derived so as to have the above plate thickness by performing a molding analysis. In each example, the reference plate thickness was 1.2 mm. In addition, in Example 1, the A pillar lower outer panel was formed by the manufacturing method or the manufacturing apparatus according to the above-described embodiment. In Comparative Example 1, the A-pillar lower outer panel was formed by the conventional drawing method.
[0156]
FIG. 33 shows a method of evaluating the collision characteristics. The inner member and the A pillar lower outer panel were joined by spot welding at intervals of 30 mm at the flange portion of the A pillar lower outer panel. As shown in FIG. 33, the two ends of the A-pillar lower outer panel were completely restrained around the entire circumference.
The rigid body was made to collide at a speed of 20 km/h from the direction shown by the arrow in FIG. The plate thickness distribution of the A pillar lower outer panel was derived by performing a molding analysis. After the rigid body came into contact with the A pillar lower outer panel, the absorbed energy at a displacement of 50 mm was evaluated.
[0157]
A method for evaluating rigidity is shown in FIG. The inner member and the A pillar lower outer panel were joined by spot welding at 30 mm intervals at the flange portion of the A pillar lower outer panel. As shown in FIG. 34, the A-pillar lower outer panel was completely constrained at two ends and the inner member at a total of three places. The plate thickness of all the inner members was 1.2 mm. The load was measured when a displacement of 1 mm was applied to the center of the top plate in the corner portion in the vehicle inner direction (direction of the arrow).
[0158]
Table 1 shows the reduction rate of the thickness of the A-pillar lower outer panel, which is the object of the collision analysis, and the results of the collision characteristics and the rigidity.
[0159]
[table 1]

[0160]
As shown in Table 1, it can be seen that Example 1 in which the reduction rate of the plate thickness in the A portion is small is superior in the collision characteristics and the rigidity of the A pillar lower outer panel.
[0161]
(Experimental Example 2)
　The shapes of Examples and Comparative Examples are shown in FIGS. 35(a) to 35(c). In the A-pillar lower outer panel of Example 2 shown in FIG. 35(a), the end of the vertical flange and the end of the vertical wall of the first part are continuous without a step, and the end of the second outward flange is The end and the end of the first outward flange are continuous without a step. In the A-pillar lower outer panel of Example 3 shown in FIG. 35(b), the width of the vertical flange is 5 mm, and the width of the second outward flange is 5 mm. Also in the case of the second embodiment, the vertical flange and the second outward flange have a transition portion in which the vertical flange and the second outward flange are continuous.
[0162]
In the A-pillar lower outer panel of Comparative Example 2 shown in FIG. 35(c), there is no vertical flange and second outward flange at the corner portion, and there is no transition portion. In other words, the A-pillar lower outer panel of Comparative Example 2 in FIG. 35(c) has a cutout portion over the entire circumference of the corner portion.
[0163]
[Table 2]

[0164]
　As can be seen from the results in Table 2, the molded article of Comparative Example 2 having no vertical flange and the second outward flange at the corner portion and having no transition portion has higher rigidity than the molded articles of Examples 2 and 3. Is inferior.
Industrial availability
[0165]
ADVANTAGE OF THE INVENTION According to this invention, the hot stamp molded product which has high impact characteristics and rigidity although it is thin and lightweight, and the manufacturing method and manufacturing apparatus of such a hot stamp molded product which can manufacture. Can be provided and is industrially useful.
Explanation of symbols
[0166]
10 A-pillar lower outer panel
11 1st part
12 Corner part
13 2nd part
14 Top plate
15 Vertical wall
16 1st outward flange
17 Vertical flange
18 2nd outward flange
19 Transition part
20 3rd outward flange
30 Manufacturing device
31 punch
31a punch shoulder R portion
31b punch bottom surface
32 blank holder
33 die
34 bending die
34a bending ridge
40 blank
50 manufacturing device
52 blank holder
52a first surface
52b bending portion
52c second surface
53 die
53a first surface
53b bending portion
53c Second surface
The scope of the claims
[Claim 1]
　Steel having at least one of a tensile strength of 1200 MPa or more and a martensitic steel structure, and having a first part, a corner part, and a second part that are sequentially connected in the longitudinal direction from one end to the other end. A hot stamp molded product made of a material,
　wherein each of the first part, the corner part and the second part is connected to the top plate and the top plate when viewed in a cross section perpendicular to the longitudinal direction. Two vertical walls;
　the second portion has a first outwardly facing flange adjacent to the vertical wall; the
corner portion has
a vertical flange extending from the vertical wall of the first portion;
a second outward flange, adjacent to the vertical wall located on the outer peripheral side of the corner portion of the two vertical walls
and a transition portion wherein said longitudinal flange second outward flange is continuous,
; having
characteristics that a Hot stamped product.
[Claim 2]

The hot stamp molded article according to claim 1 　, which is an A pillar lower outer panel .
[Claim 3]
　A method for manufacturing a hot stamped product according to claim 1 or 2, wherein the blank is press-molded by a hot stamping method
　, wherein the blank is arranged facing a punch and a blank holder, and the blank holder. Between the die and the bending die, the
　portion of the blank formed in the top plate is supported by the punch,
　and the two vertical walls of the first portion and the corner portion of the blank are Among them, at least a part of the portion formed on the vertical wall located on the outer peripheral side of the corner portion is sandwiched by the blank holder and the die, and the
　die and the bending die are relatively brought close to the punch. At least a part of the portion formed on the vertical wall is drawn by the punch, the blank holder and the die, and the remaining portion except the drawn portion is bent by the punch and the bending die. A
method for manufacturing a hot stamped article, comprising:
[Claim 4]
　In the blank, at least a part of the vertical wall and the vertical flange located on the outer peripheral side of the corner portion is narrowed down before reaching the molding bottom dead center, and the blank holder and the die. The
method for manufacturing a hot stamp molded article according to claim 3 , wherein the sandwiching by means of is completed .
[Claim 5]
　The hot stamp molded product according to claim 3, further comprising a pad arranged to face the punch, and a portion of the blank to be molded on the top plate is sandwiched by the punch and the pad. Method.
[Claim 6]
　The die and the blank holder both come into contact with a portion of the two vertical walls of the first portion and the corner portion of the blank formed on the vertical wall located on the outer peripheral side of the corner portion. A first surface sandwiched between the first surface, a bent portion that is continuous with the first surface, and a second surface that is continuous with the bent portion and is inclined with respect to the first surface in a direction away from the bending die, The hot stamp molded article according to any one of claims 3 to 5,
　wherein the second surface of each of the die and the blank holder is formed by drawing the blank together with bending by the punch and the bending die
. Production method.
[Claim 7]
　In the blank in the process of forming, the end of the portion constrained by the second surface of the die and the blank holder, and the portion of the portion that is bent and formed by the punch and the bending die to become the first outward flange. The
method for manufacturing a hot stamp molded product according to claim 6, wherein the difference in the pressing direction from the end portion is 20 mm or less .
[Claim 8]
　The bent portion of the die is provided at a height position near the height position of the bending ridge line portion of the bending die, and the bent portion of the blank holder is at the height position of the punch shoulder R portion of the punch. The
method for manufacturing a hot stamp molded article according to claim 6 or 7 , which is provided at a height position in the vicinity of .
[Claim 9]
　The inclination angle of the second surface with respect to the first surface in the blank holder is (inclination angle of punch shoulder R portion of the punch−30 degrees) or more and (inclination angle of punch shoulder R portion of the punch+30 degrees). The
method for producing a hot stamped article according to any one of claims 6 to 8 , which is as follows .
[Claim 10]
　Wherein the first surface of the blank holder, when said blank is sandwiched by the die and the blank holder, present at the height position substantially the height position matching the punch bottom surface of the punch,
according to claim 6-9 A method for producing a hot stamp molded article according to any one of 1.
[Claim 11]
　The first surface of the die is present at a height position that substantially coincides with a height position of a surface on which the bending ridge line portion of the bending die exists when the blank is sandwiched by the die and the blank holder.
A method for manufacturing a hot stamp molded product according to any one of claims 6 to 10.
[Claim 12]
　An apparatus for producing a hot stamped product according to claim 1 or 2 by press-forming a blank by a hot stamping method
　, comprising a punch and a blank holder, and a die arranged to face the blank holder. , A bending
　die, and the die and the bending die and the punch can relatively approach and separate from each other, and the
　punch can support a portion of the blank that is formed on the top plate. And the
　blank holder and the die are at least one of the two vertical walls of the first portion and the corner portion of the blank that are formed on the vertical wall located on the outer peripheral side of the corner portion. While it is possible to sandwich the portion, the
　punch, the blank holder and the die, at least a part of the portion formed in the vertical wall located on the outer peripheral side of the corner portion can be drawn and, An
apparatus for manufacturing a hot stamp molded product, wherein the punch and the bending die are capable of bending the remaining portion except the portion to be drawn .
[Claim 13]
　The blank holder and the die are sandwiched between at least a part of a part of the two vertical walls of the first part and the corner part of the blank that are formed on a vertical wall located on the outer peripheral side of the corner part.
13. The hot stamp molded article manufacturing apparatus according to claim 12, wherein the step is finished by drawing through before reaching a molding bottom dead center .
[Claim 14]

The hot stamp molded article according to claim 12 or 13, 　further comprising a pad arranged to face the punch, wherein the punch and the pad sandwich a portion of the blank to be molded on the top plate . manufacturing device.
[Claim 15]
　The die and the blank holder both come into contact with a portion of the two vertical walls of the first portion and the corner portion of the blank formed on the vertical wall located on the outer peripheral side of the corner portion. has a first side, a bent portion continuous with the first surface and a second surface which is inclined in a direction away from the bending tool relative to the first surface with continuous to the bent portion sandwiching Te,
wherein Item 15. An apparatus for manufacturing a hot stamp molded product according to any one of Items 12 to 14.
[Claim 16]
　The bent portion of the die is provided at a height position near the height position of the bending ridge line portion of the bending die, and the bent portion of the blank holder is at the height position of the punch shoulder R portion of the punch.
16. The hot stamp molded product manufacturing apparatus according to claim 15 , which is provided at a height position near the position .
[Claim 17]
　An inclination angle of the second surface with respect to the first surface in the blank holder is (an inclination angle of a punch shoulder R portion of the punch −30 degrees) or more and (an inclination angle of a punch shoulder R portion of the punch +30 degrees). The
apparatus for manufacturing a hot stamped article according to claim 15 or 16 , which is as follows .
[Claim 18]
　Wherein the first surface of the blank holder, when said blank is sandwiched by the die and the blank holder, present at the height position substantially the height position matching the punch bottom surface of the punch,
according to claim 15-17 An apparatus for manufacturing a hot stamp molded article according to any one of 1.
[Claim 19]
　The first surface of the die is present at a height position that substantially coincides with a height position of a surface on which the bending ridge line portion of the bending die exists when the blank is sandwiched by the die and the blank holder.
An apparatus for manufacturing a hot stamp molded product according to any one of claims 15 to 18.