Method for manufacturing press-formed article and press molding apparatus

Abstract

To provide a manufacturing method for manufacturing a press-formed article having a shape that includes both a portion where an outer contour line of a top plate portion and a vertical wall portion are concavely curved and a portion where they are convexly curved.SOLUTION: In a method for manufacturing a press-formed article including: a top plate portion 2 having an S-shaped section in which a concavely curved portion and a convexly curved portion are continuously connected in a part of an outer contour line; a concave top plate ridge line portion; a convex top plate ridge line portion; a concavely curved vertical wall portion 12; a convexly curved vertical wall portion 22; a concave flange ridge line portion; a convex flange ridge line portion; a concave flange portion 14; and a convex flange portion 24, the concavely curved vertical wall portion 12 and the convexly curved vertical wall portion 22 are formed by moving a die 150 relative to a punch 110 and a pad 140 along a vertical wall inclination direction V, while maintaining a distance between a punch vertical wall surface and a die vertical wall surface to be equal to or greater than 1.0 times and equal to or less than 1.2 times a plate thickness of a material metal plate, thereby manufacturing the press-formed article.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a press-formed product and a press-forming apparatus. [Background technology]

[0002] Many automotive structural components have shapes with ridges 54 and 55 connecting a top plate 51, a vertical wall 52, and a flange 53, as shown in Figure 1, and are manufactured by press forming. When the ridges 54 and 55 of such structural components are curved as shown in Figures 2(a) and 2(b), wrinkles are likely to occur due to the difference in cross-sectional line length before and after forming. Forming shapes with such curved profiles is generally performed by drawing to prevent wrinkles. This drawing process involves pressing the periphery of the raw metal sheet against a die using a wrinkle-retaining mold (holder) to restrict the flow of material, resulting in significant stretching of the material during forming. Therefore, to achieve good forming, the raw metal sheet must have a certain level of elongation.

[0003] In recent years, there has been a demand for higher-strength materials to be used in auto body frame parts in order to increase the strength and reduce the weight of automobile bodies. However, in general, with metal sheets such as steel sheets and aluminum alloy sheets, the ductility of the material decreases as the material strength increases. Therefore, it is not easy to form frame parts with curved profiles using high-strength metal sheets with low ductility.

[0004] Patent Document 1 discloses a method for forming a press part, which includes a top plate portion and a vertical wall portion connected to the top plate portion via a bent portion having an arc-shaped curved portion and having a flange portion on the opposite side of the bent portion, with the top plate portion being located outside the arc of the vertical wall portion. The part formed by this forming method can be described as a part including an outline of the top plate portion and a concavely curved portion in the vertical wall portion. To form such a part, the forming method described in Patent Document 1 involves placing a base metal sheet between a die, a pad, and a bending die, applying pressure with the pad to at least a portion of the base metal sheet corresponding to the top plate portion, which serves as an out-of-plane deformation suppression region, and moving the die and the bending die relative to each other in the vertical direction while the end of the portion of the base metal sheet corresponding to the lower L-shape is flush with the top plate portion, thereby forming the vertical wall portion and the flange portion while sliding the end of the portion of the base metal sheet corresponding to the lower L-shape over the portion of the die corresponding to the top plate portion.

[0005] Patent Document 2 discloses a method for manufacturing a part having a top plate portion with a curved outer peripheral edge that is partially concavely curved inward, a vertical wall portion continuous with the curved outer peripheral edge, and a flange portion that is continuous with the vertical wall portion and bent to the opposite side of the top plate portion. This part can be considered to be a part that includes an outline of the top plate portion and a concavely curved portion in the vertical wall portion. To form such a part, the forming method described in Patent Document 2 involves clamping a clamping region, which is a region of a metal plate that includes at least a portion of the area corresponding to the top plate portion, between a lower mold and a pad, and moving an upper mold in a pressing direction relative to the lower mold. This bends the vertical wall portion and the flange portion while moving at least a portion of the material in the clamping region clamped between the lower mold and the pad toward the vertical wall portion. During the bending process, the metal plate portion clamped between the lower mold and the pad is continuously subjected to out-of-plane bending and unbending deformation at bending portions extending in a direction intersecting the material movement direction, thereby controlling the material movement.

[0006] Patent Document 3 discloses a method for forming a part in which the outline of the top plate and the vertical wall include convexly curved portions. As described in the latter part of paragraph

[0006] of Patent Document 3, the forming method of Patent Document 3 is a method in which the distance between the edge of the corner of the die hole and the edge of the blank is made wider than in the past, that is, the blank has a shape in which convex portions are provided at the corners, and the blank is used for forming. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5168429 [Patent Document 2] Patent No. 6648867 [Patent Document 3] Patent No. 7216937 Summary of the Invention [Problem to be solved by the invention]

[0008] Patent Documents 1 and 2 disclose methods for forming a component from a metal plate including a concavely curved portion in the outer contour of the top panel and a vertical wall portion, and Patent Document 3 discloses a method for forming a component from a metal plate including a convexly curved portion in the outer contour of the top panel and a vertical wall portion. However, some automobile frame components have a continuous concavely curved portion 10 and a convexly curved portion 20, as shown in Figure 3.

[0009] The molding methods described in Patent Documents 1 and 2 can only mold parts in which the outline of the top plate and the vertical wall portions include concavely curved portions, and cannot properly mold parts in which the concavely curved portion 10 and the convexly curved portion 20 are continuous, as shown in Fig. 3. On the other hand, the molding method described in Patent Document 3 can only mold parts in which the outline of the top plate and the vertical wall portions include convexly curved portions, and cannot properly mold parts in which the concavely curved portion 10 and the convexly curved portion 20 are continuous, as shown in Fig. 3.

[0010] Furthermore, the forming methods described in Patent Documents 1 and 2 involve pad bending, so the flange portion is not constrained during the forming process, whereas the forming method described in Patent Document 3 involves drawing, so the flange portion is held down with a holder during the forming process to suppress out-of-plane deformation. Therefore, the forming methods disclosed in Patent Documents 1 and 2, which form a part including a concavely curved portion in the contour line of the top plate and vertical wall portions, cannot be combined with the forming method disclosed in Patent Document 3, which forms a part including a convexly curved portion in the contour line of the top plate and vertical wall portions. In other words, with the prior art, it was difficult to successfully form a part in which a concavely curved portion 10 and a convexly curved portion 20 are connected, as shown in FIG. 3 .

[0011] The present invention has been made in consideration of the above circumstances, and aims to provide a manufacturing method and press-molding apparatus for producing press-molded products having a shape in which the outer line of the top plate portion and the vertical wall portion include both concavely curved portions and convexly curved portions. [Means for solving the problem]

[0012] The inventors conducted technical studies and investigations into press forming of metal plates through press experiments and numerical simulations of press forming using the finite element method.

[0013] First, we investigated a method for forming a press-formed product having a concavely curved portion and a convexly curved portion. FIG. 4 is a diagram illustrating the schematic configuration of a concavely curved portion 10 and a convexly curved portion 20, showing a portion of a press-formed product 1. The press-formed product 1 shown in FIG. 4 has a top plate portion 2, and a portion of the outer shape of the top plate portion 2 has a shape in which a concavely curved portion and a convexly curved portion are continuously connected. The concavely curved portion 10 shown in FIG. 4 includes a concave top plate ridge portion 11, a concavely curved vertical wall portion 12, a concave flange ridge portion 13, and a concave flange portion 14. The convexly curved portion 20 includes a convex top plate ridge portion 21, a convexly curved vertical wall portion 22, a convex flange ridge portion 23, and a convex flange portion 24.

[0014] The concave top ridge portion 11 is a ridge portion connected to the concavely curved portion of the top plate portion 2. The concavely curved vertical wall portion 12 is a wall portion connected to the concave top ridge portion 11 on the side opposite the top plate portion 2. The concave flange ridge portion 13 is a ridge portion connected to the concavely curved vertical wall portion 12 on the side opposite the concave top ridge portion 11. The concave flange portion 14 is a flange connected to the concave flange ridge portion 13 on the side opposite the concavely curved vertical wall portion 12. The concave top ridge portion 11 and the concave flange ridge portion 13 each extend along the extension direction of the concavely curved outline of the top plate portion 2.

[0015] The convex top ridgeline portion 21 is a ridgeline portion connected to the convexly curved portion of the top plate portion 2. The convexly curved vertical wall portion 22 is a wall portion connected to the convex top ridgeline portion 21 on the side opposite the top plate portion 2. The convex flange ridgeline portion 23 is a ridgeline portion connected to the convexly curved vertical wall portion 22 on the side opposite the convex top ridgeline portion 21. The convex flange portion 24 is a flange connected to the convex flange ridgeline portion 23 on the side opposite the convexly curved vertical wall portion 22. The convex top ridgeline portion 21 and the convex flange ridgeline portion 23 each extend along the extension direction of the convexly curved outline of the top plate portion 2. In addition, in the extension direction of the convexly curved outer contour of the top plate portion 2, the convex top plate ridge portion 21 is connected to the concave top plate ridge portion 11, the convexly curved vertical wall portion 22 is connected to the concavely curved vertical wall portion 12, the convex flange ridge portion 23 is connected to the concave flange ridge portion 13, and the convex flange portion 24 is connected to the concave flange portion 14.

[0016] That is, the press-molded product 1 illustrated in FIG. a top plate portion 2 having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of the outline; a concave top ridge portion 11 connected to the concavely curved portion of the top portion 2; a convex top ridge portion 21 connected to the convexly curved portion of the top portion 2; a concave curved vertical wall portion 12 connected to the concave top board ridge portion 11 on the opposite side from the top board portion 2 side; a convex curved vertical wall portion 22 connected to the convex top board ridge portion 21 on the opposite side from the top board portion 2 side; a concave flange ridge line portion 13 connected to the concave curved vertical wall portion 12 on the side opposite to the concave top plate ridge line portion 11 side; a convex flange ridge portion 23 connected to the convex curved vertical wall portion 22 on the opposite side from the convex top plate ridge portion 21; a concave flange portion 14 connected to the concave flange ridge portion 13 on the side opposite to the concave curved vertical wall portion 12 side; and a convex flange portion 24 connected to the convex flange ridge portion 23 on the side opposite to the convexly curved vertical wall portion 22 side.

[0017] When a press-formed product 1 such as that shown in FIG. 4 is manufactured by common press-forming methods such as drawing and bending, the material of the portions corresponding to the concavely curved vertical wall portion 12 and the concave flange portion 14 is pulled outward from the concavely curved region and significantly stretched during the forming process, as indicated by the arrows in FIG. 5. This phenomenon occurs primarily because the widthwise length of the concavely curved vertical wall portion 12 after forming is longer than the widthwise length (length along the curvature) of the portion of the base metal sheet corresponding to the concavely curved vertical wall portion 12 before forming, and the longitudinal length of the concave flange portion 14 after forming is longer than the longitudinal length (length along the curvature) of the portion of the base metal sheet corresponding to the concave flange portion 14 before forming. In other words, the base metal sheet is stretched due to the difference in geometric shape before and after forming. This type of deformation occurring during the forming process is generally referred to as "stretch flange deformation."

[0018] Therefore, in order to satisfactorily form the concavely curved vertical wall portion 12 and the concave flange portion 14, the base metal sheet must have sufficient elongation in consideration of the occurrence of stretch flange deformation. In addition, for example, when the curvature of the concavely curved vertical wall portion 12 and the concave flange portion 14 is large and the curvature is sharp, or when the height of the concavely curved vertical wall portion 12 is high, the difference in geometric shape before and after forming becomes even greater, and therefore the base metal sheet must have even greater elongation.

[0019] Furthermore, when a press-formed product 1 such as that shown in FIG. 4 is manufactured by common press-forming methods such as drawing and bending, the material in the portions corresponding to the convexly curved vertical wall portion 22 and the convex flange portion 24 is significantly compressed during the forming process, as indicated by the arrows in FIG. 5, resulting in wrinkles. This phenomenon occurs primarily because the widthwise length of the convexly curved vertical wall portion 22 after forming is shorter than the widthwise length (length along the curvature direction) of the portion of the base metal sheet corresponding to the convexly curved vertical wall portion 22 before forming, and the longitudinal length of the convex flange portion 24 after forming is shorter than the longitudinal length (length along the curvature direction) of the portion of the base metal sheet corresponding to the convex flange portion 24 before forming. In other words, the base metal sheet is compressed due to the difference in geometric shape before and after forming. This type of deformation occurring during the forming process is generally referred to as "shrinkage flange deformation."

[0020] To prevent wrinkles due to the shrinkage flange deformation, for example, a blank holder is used to press the portion of the base metal sheet corresponding to the convex flange portion 24 against a die, and drawing is performed while applying pressure to the holder. This prevents out-of-plane deformation of the portion of the base metal sheet corresponding to the convex flange portion 24 and increases the material inflow resistance. This suppresses the inflow of material into the convex flange portion 24, allowing the convexly curved vertical wall portion 22 and the convex flange portion 24 to be formed while preventing wrinkles. In this forming process, the inflow of material into the portions of the base metal sheet corresponding to the convexly curved vertical wall portion 22 and the convex flange portion 24 is reduced, so the material in these portions is significantly stretched during forming. Therefore, sufficient extensibility is required for the base metal sheet when forming the convexly curved portion. In addition, for example, when the curvature of the convexly curved vertical wall portion 22 and the convex flange portion 24 is large and sharp, or when the height of the convexly curved vertical wall portion 22 is high, the difference in geometric shape before and after forming becomes even greater, and therefore the base metal sheet requires even greater extensibility.

[0021] As described above, both stretch flange deformation and shrink flange deformation occur during forming of the press-formed product 1 including the concavely curved region 10 and the convexly curved region 20 illustrated in Fig. 4. Therefore, when attempting to manufacture the press-formed product 1 by a general press forming method, the base metal sheet must have high elongation, making it difficult to achieve good forming. In particular, when the curvature is sharp or when a material with high tensile strength but low elongation is used, good forming becomes even more difficult.

[0022] Incidentally, when a metal plate is press-formed into a press panel to manufacture a part having a shape with a top panel, vertical wall portions, and flange portions, such as a part with a hat-shaped cross section found in automobile frame components, when the press panel is removed from the mold after press forming, the stress (residual stress) generated within the press panel by the plastic deformation caused by the press forming is released, causing the press panel to deform (springback deformation), and the vertical wall portions deform so as to open outward from the hat-shaped cross section (opening deformation).

[0023] Therefore, in order to obtain a pressed panel of a predetermined shape, the mold shape is generally modified (anticipatory modification) in advance to take into account springback deformation, so that the mold shape is deformed in the direction opposite to the mouth opening direction (a shape that is more closed than the predetermined shape).When a raw metal sheet is formed using such an anticipatory modification mold, the mouth becomes more closed than the predetermined shape at the bottom dead center of the press, and then springback deformation causes mouth opening deformation, allowing the pressed panel to be formed into the predetermined shape.

[0024] However, when taking measures against such mouth-opening deformation, if the angle between the top plate and vertical wall of the part shape is 90 degrees, the angle between the top plate and vertical wall on the mold side where projection correction was performed must be less than 90 degrees, but in this case, the vertical wall on the mold side will have a negative angle, making drawing impossible. For this reason, many press panels that have a top plate, vertical wall, and flange are designed to have a mouth-opening shape in which the angle between the top plate and vertical wall of the press panel after molding is greater than 90 degrees, in order to prevent the vertical wall on the mold side from becoming a negative angle after projection correction.

[0025] Therefore, we will consider manufacturing the press-formed product shown in Figure 6(a), which includes an S-shaped curved portion where the angle between the top plate portion and the vertical wall portion is greater than 90 degrees, from a high-strength steel plate with low elongation. As mentioned above, if the part shown in Figure 6(a) is subjected to general drawing using a mold consisting of, for example, punch 61, holders 62 and 63, and die 64 shown in Figure 6(b), it will break at the concavely curved vertical wall portion 12 and the concave flange portion 14, and wrinkles will occur at the convexly curved vertical wall portion 22 and the convex flange portion 24.

[0026] FIG. 7 shows the state of the raw metal sheet S in relation to the operation of the press-forming device at the a1-a2 cross section shown in FIG. 6(a). FIG. 7(a) shows the initial state of forming, FIG. 7(b) shows the state during forming, and FIG. 7(c) shows the state after forming is completed. The open arrows in the figure indicate the direction of the pressure applied to the holders 62 and 63, and the filled arrows in the figure indicate the direction of movement of the die 64. When press-forming is performed using the mold illustrated here, as shown in FIGS. 7(a) and 7(b), the distance between the vertical wall surface of the punch 61 and the vertical wall surface of the die 64, which form the vertical wall portion of the part, is greater than the thickness of the raw metal sheet S during forming. The wrinkles in the convexly curved vertical wall portion 22 described above occur in the gap between the vertical wall surface of the punch 61 and the vertical wall surface of the die 64. One of the causes of wrinkles is that this gap is greater than the thickness of the raw metal sheet S during forming.

[0027] The inventors focused on the cause of wrinkles and discovered a method of press-forming while maintaining the gap between the punch and die for forming the convexly curved vertical wall portion at the same distance as the thickness of the material metal plate or at a distance slightly wider than the thickness. They then discovered that press-forming using this method can suppress the occurrence of wrinkles in the convexly curved vertical wall portion, and that the material of the convexly curved vertical wall portion can move toward the concavely curved vertical wall portion, thereby reducing the amount of elongation of the material during the formation of the concavely curved vertical wall portion.

[0028] The present invention has been made based on the above findings. That is, one aspect of the present invention that solves the above-mentioned problems includes a top plate portion having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of an outline of the top plate portion, a concave top plate ridge portion connected to the concavely curved portion of the top plate portion, a convex top plate ridge portion connected to the convexly curved portion of the top plate portion, a concavely curved vertical wall portion connected to the concave top plate ridge portion on the opposite side to the top plate portion side, a convexly curved vertical wall portion connected to the convex top plate ridge portion on the opposite side to the top plate portion side, and a top plate ridge portion of the concavely curved vertical wall portion. a concave flange ridge line portion connected to the convexly curved vertical wall portion on the side opposite to the convex top plate ridge line portion side, a convex flange ridge line portion connected to the convexly curved vertical wall portion on the side opposite to the convex top plate ridge line portion side, a concave flange portion connected to the concave flange ridge line portion on the side opposite to the concave curved vertical wall portion side, and a convex flange portion connected to the convex flange ridge line portion on the side opposite to the convexly curved vertical wall portion side, wherein an angle formed by the top plate portion and the concave curved vertical wall portion and an angle formed by the top plate portion and the convexly curved vertical wall portion are each greater than 90 degrees, A press forming apparatus including a punch, a holder disposed on a side of the punch, a pad disposed opposite the punch, and a die disposed opposite the holder, wherein the punch includes punch vertical wall surfaces parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, and the punch includes punch vertical wall surfaces parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, and the die includes die vertical wall surfaces parallel to the inclination directions of the vertical walls, and the die includes die vertical wall surfaces parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, and the punch includes punch vertical wall surfaces parallel to the inclination directions of the vertical walls, and the die includes die ... vertical wall surfaces parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, and the die vertical wall surfaces are formed by pressing the punch, the punch, the holder, the pad, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch, the punch When producing a press-formed product, at least a portion of the portion of the base metal plate corresponding to the S-shaped portion of the top plate portion is clamped and restrained by the punch and the pad, and at least a portion of the portions of the base metal plate corresponding to the concavely curved vertical wall portion, the concave flange ridge portion, the concave flange portion, the convexly curved vertical wall portion, the convex flange ridge portion and the convex flange portion are clamped by the holder and the die, and the distance between the punch vertical wall surface and the die vertical wall surface is 1.0 times or more the thickness of the base metal plate, 1.The method is characterized in that the concavely curved vertical wall portion and the convexly curved vertical wall portion are formed by moving the die relative to the punch and the pad along the vertical wall inclination direction while maintaining the inclination angle to be no more than twice that of the punch and pad, thereby producing the press-formed product.

[0029] Unlike the above-described manufacturing method of a press-formed product, if the distance between the punch vertical wall surface and the die vertical wall surface is less than 1.0 times the thickness of the base metal sheet, the portion of the base metal sheet corresponding to the vertical wall portion will be ironed, resulting in defects such as a significant increase in forming load, cracking due to elongation of the material, or warping of the vertical wall portion. Furthermore, if the distance between the punch vertical wall surface and the die vertical wall surface is more than 1.2 times the thickness of the base metal sheet, wrinkles are likely to occur in the material in the portion corresponding to the convexly curved vertical wall portion within the gap between the punch vertical wall surface and the die vertical wall surface during forming. On the other hand, if press forming is performed while maintaining the distance between the punch vertical wall surface and the die vertical wall surface at 1.0 to 1.2 times the thickness of the base metal sheet, as in the above-described manufacturing method of a press-formed product, ironing of the vertical wall portion will not occur, and wrinkles can be suppressed.

[0030] According to another aspect of the present invention for solving the above-mentioned problems, there is provided a top plate portion having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of an outline, a concave top plate ridge portion connected to the concavely curved portion of the top plate portion, a convex top plate ridge portion connected to the convexly curved portion of the top plate portion, a concavely curved vertical wall portion connected to the side opposite to the top plate portion side of the concave top plate ridge portion, a convexly curved vertical wall portion connected to the side opposite to the top plate portion side of the convex top plate ridge portion, a concave flange ridge portion connected to the side opposite to the concave top plate ridge portion side of the concave curved vertical wall portion, and a concave flange portion connected to the side opposite to the concave curved vertical wall portion side of the concave flange ridge portion, and the angle formed by the convexly curved vertical wall portion is greater than 90 degrees, the press forming apparatus comprising: a punch; a holder arranged on the side of the punch; a pad arranged opposite the punch; and a die arranged opposite the holder, wherein the punch has a punch top surface and a punch vertical wall surface including a concavely curved surface that is concavely curved and a convexly curved surface that is convexly curved, the angle formed by the punch top surface and the punch vertical wall surface is greater than 90 degrees, the die has a die vertical wall surface having a shape corresponding to the punch vertical wall surface, the die vertical wall surface is parallel to the punch vertical wall surface, and the die is configured to be movable relative to the punch and the pad along a direction parallel to the punch vertical wall surface. [Effects of the Invention]

[0031] It is possible to satisfactorily manufacture a press-molded product having a shape in which the contour line of the top plate portion and the vertical wall portion include both concavely curved portions and convexly curved portions. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a diagram showing a typical hat-shaped part that is applied to an automobile frame part. [Figure 2] 10A and 10B are diagrams illustrating an example of a component in which the outline of a top panel and vertical wall portions are concavely curved and a component in which the outline of a top panel and vertical wall portions are convexly curved; [Figure 3] FIG. 10 is a diagram illustrating an example of a component including a shape in which a concavely curved portion and a convexly curved portion are connected to each other. [Figure 4] 10A and 10B are diagrams for explaining the schematic configuration of a concavely curved portion and a convexly curved portion. [Figure 5] FIG. 1 is a diagram for explaining stretch flange deformation that occurs when a concavely curved portion is formed, and shrink flange deformation that occurs when a convexly curved portion is formed. [Figure 6] 1 is a diagram showing an example of a press-formed product including an S-shaped curved portion in which the angle between the top plate portion and the vertical wall portion is greater than 90 degrees, and an example of a press-forming device (comparison example). [Figure 7] 6(a) is a diagram showing the state of the raw metal sheet in response to the operation of the press-forming device in the a1-a2 cross section shown in FIG. 6(a). [Figure 8] 1 is a diagram showing a schematic configuration of a press-formed product and a press-forming device according to a first embodiment. FIG. [Figure 9] FIG. 2 is a diagram for explaining the shapes of a punch and a die according to the first embodiment. [Figure 10] 8(a) is a diagram showing the state of the raw metal sheet in response to the operation of the press-forming device in the a1-a2 cross section shown in FIG. 8(a). [Figure 11] 10A and 10B are diagrams showing examples of shapes of press-formed products in which the concavely curved and convexly curved portions of the outline of the top plate portion include straight line portions; [Figure 12] FIG. 10 is a diagram showing a schematic configuration of a press-formed product and a press-forming device according to a second embodiment. [Figure 13] 12(a) is a diagram showing the state of the raw metal sheet in response to the operation of the press-forming device in the a1-a2 cross section shown in FIG. [Figure 14] FIG. 10 is a diagram showing a press-formed product according to a third embodiment. [Figure 15] FIG. 10 is a diagram showing a press-formed product formed as an intermediate product according to a third embodiment. [Figure 16] 10 is a diagram showing a schematic configuration of a press forming apparatus according to a third embodiment and the shape of a punch. FIG. [Figure 17]FIG. 1 is a diagram showing the shapes of press-molded products formed in Molding Examples 1 to 11. [Figure 18] FIG. 1 is a diagram showing the shapes of material metal plates used in forming examples 1 to 11. [Figure 19] FIG. 2 is a diagram showing a press molding device used in Molding Example 1. [Figure 20] FIG. 10 is a diagram showing a press molding device used in Molding Example 2. [Figure 21] FIG. 1 is a diagram showing a press molding apparatus used in Molding Example 3 and Molding Examples 5 to 11. [Figure 22] 17(a) is a diagram showing the state of a raw metal sheet in response to the operation of the press-forming device of Forming Example 3 in the a1-a2 cross section shown in FIG. 17(a). FIG. [Figure 23] FIG. 10 is a diagram showing a press molding device used in Molding Example 4. [Figure 24] 17(a) is a diagram showing the state of a material metal sheet in response to the operation of the press-forming device of Forming Example 4 in the a1-a2 cross section shown in FIG. 17(a). FIG. [Figure 25] 12 is a diagram showing the shape of a press-molded product formed in Molding Example 12. FIG. [Figure 26] FIG. 11 is a diagram showing the shape of a press-molded product formed in Molding Example 13. [Figure 27] 13 is a diagram showing the shape of a press-molded product formed in Molding Example 14. FIG. [Figure 28] FIG. 11 is a diagram showing a press molding apparatus used in Molding Example 14. [Figure 29] 28 is a diagram showing the state of a raw metal sheet in response to the operation of the press-forming device of Forming Example 14 in the a1-a2 cross section shown in FIG. 27. FIG. [Figure 30] 13 is a diagram showing the shape of a press-molded product formed in Molding Example 15. FIG. [Figure 31] FIG. 10 is a diagram showing a press molding apparatus used in Molding Example 15. [Figure 32] 10 is a diagram for explaining why cracks occur in the concave flange portion of the press-formed product formed in Forming Example 15. FIG. [Figure 33] FIG. 10 is a diagram showing the shape of the press molding device and punch used in Molding Example 16. [Figure 34] FIG. 10 is a diagram showing a press-molded product as an intermediate product molded in Molding Example 16. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0034] First Embodiment In the first embodiment, a method for manufacturing the press-formed product 1 shown in FIG. 8(a) using the press-forming apparatus 100 shown in FIG. 8(b) will be described. The press-formed product 1 shown in FIG. 8(a) is the same as the part shown in FIG. 6(a), except that the angle between the top plate and the vertical wall is greater than 90 degrees, and one of the two vertical wall portions has a concave curved portion 10 and a convex curved portion 20 formed in the vertical wall portion. The base metal plate used to manufacture the press-formed product 1 is, for example, a steel plate or an aluminum alloy plate. The tensile strength of the base metal plate is not particularly limited, and even a high-strength material having a strength of 500 MPa or more can be used as the base metal plate.

[0035] The press forming apparatus 100 illustrated in Figure 8(b) includes a punch 110, two holders 120 and 130 arranged on either side of the punch 110 with the punch 110 sandwiched between them, a pad 140 arranged opposite the punch 110, and two dies 150 and 160 arranged opposite the holders 120 and 130.

[0036] 9A and 9B are diagrams illustrating the shapes of a punch 110 and a die 150 according to the first embodiment. As shown in FIG. 9A, the punch 110 has a punch top surface 111 that contacts a portion of the base metal sheet corresponding to the top plate portion 2, and a punch vertical wall surface 112 that includes an S-shaped portion corresponding to the concavely curved vertical wall portion 12 and the convexly curved vertical wall portion 22. The "vertical wall inclination direction V" in the figure is the inclination direction of the vertical wall portion at an angle with respect to the direction perpendicular to the top plate portion of the press-formed product. The punch vertical wall surface 112 includes a concavely curved surface and a convexly curved surface that are parallel to the vertical wall inclination direction V. As described above, in the press-formed product to be formed in the technology disclosed herein, the angle between the top plate portion and the vertical wall portion is greater than 90 degrees, so the vertical wall portion is inclined outward with respect to the direction perpendicular to the top plate portion, and the punch vertical wall surface 112 that includes the S-shaped portion extends parallel to the inclination direction (vertical wall inclination direction).

[0037] On the side of the punch 110 opposite the punch vertical wall surface 112, there is formed a punch vertical wall surface 113 for forming the general vertical wall portion 3 of the press-molded product 1, and a vertical surface 114 extending downward from the lower end of the punch vertical wall surface 113.

[0038] 8(b), the inner surface (the surface facing the punch 110) of the holder 120 arranged on the side that forms the S-shaped curved portion extends parallel to the punch vertical wall surface 112, and the inner surface of the holder 120 and the punch vertical wall surface 112 are in a state of almost contact. On the other hand, the inner surface of the other holder 130 (the surface facing the punch 110) extends parallel to the vertical surface 114, and a gap exists between the inner surface of the holder 130 and the punch vertical wall surface 112.

[0039] 9(b), the die 150 has a die vertical wall surface 151 including an S-shaped portion corresponding to the shapes of the concavely curved vertical wall portion 12 and the convexly curved vertical wall portion 22. This die vertical wall surface 151 includes a concavely curved surface that is concavely curved and a convexly curved surface that is convexly curved, and is a surface parallel to the punch vertical wall surface 112. In addition, the die vertical wall surface 151 is a surface offset outward in the width direction of the punch 110 from the punch vertical wall surface 112 by a distance 1.0 to 1.2 times the plate thickness of the raw metal plate.

[0040] The holder 120 and the die 150 are configured to be movable relative to the punch 110 and the pad 140 along the vertical wall inclination direction V. In other words, the holder 120 and the die 150 are configured to be movable in a direction parallel to the punch vertical wall surface 112.

[0041] Next, a method for manufacturing the press-formed product 1 using the above-mentioned press-forming apparatus 100 will be described in more detail. Fig. 10 is a diagram showing the state of the raw metal sheet relative to the operation of the press-forming apparatus in the a1-a2 cross section shown in Fig. 8(a). Fig. 10(a) shows the initial state of forming, Fig. 10(b) shows the state during forming, and Fig. 10(c) shows the state after forming is completed. The white arrows in the figure indicate the direction of the pressure applied to the holders 120, 130 and pad 140, and the black arrows in the figure indicate the direction of movement of the dies 150, 160.

[0042] In the press forming according to this embodiment, first, as shown in Fig. 10(a), at least a part of the portion of the raw metal sheet S that corresponds to the top plate portion 2 of the press-formed product 1 is clamped and restrained between a punch 110 and a pad 140. The cross-sectional view shown in Fig. 10 corresponds to the a1-a2 cross section in Fig. 8(a), and therefore the portion clamped by the punch 110 and the pad 140 shown in Fig. 10(a) is the portion that corresponds to the S-shaped portion of the top plate portion 2 of the raw metal sheet S.

[0043] Furthermore, at least a portion of the portions of the raw metal sheet S corresponding to the concavely curved vertical wall portion 12, the concave flange ridge portion 13, the concave flange portion 14, the convexly curved vertical wall portion 22, the convex flange ridge portion 23, and the convex flange portion 24 of the press-formed product 1 is clamped between the holder 120 and the die 150. In addition, the portion of the raw metal sheet S corresponding to the vertical wall portion 3 is clamped between the holder 130 and the die 160.

[0044] 10(b), with the raw metal sheet S sandwiched between the punch 110 and pad 140, the holder 120 and die 150, and the holder 130 and die 160, the die 150 is lowered along the inclination direction V of the vertical wall, and the die 160 is lowered along the vertical direction. At this time, forming is performed while maintaining the distance between the vertical wall surface of the die on the side of the die 150 that forms the S-shaped curved portion and the vertical wall surface of the punch to be 1.0 to 1.2 times the thickness of the raw metal sheet S.

[0045] 10(c), the dies 150, 160 are moved to the bottom dead center of the press, thereby forming the press-formed product 1 according to this embodiment. According to this forming method, even if the portion of the material metal sheet S corresponding to the convexly curved vertical wall portion 22 is subjected to a compressive force in the width direction (the direction along the curvature) during the forming process, this portion is restrained by the die 150 and the holder 120, so that compression in the width direction is suppressed and the occurrence of wrinkles in the convexly curved vertical wall portion 22 is suppressed.

[0046] Furthermore, material in the portion of the raw metal sheet S corresponding to the convexly curved vertical wall portion 22 before forming will not fit within the convexly curved vertical wall portion 22 after forming, but will be pushed out toward the concavely curved vertical wall portion 12 adjacent to the convexly curved vertical wall portion 22. On the other hand, tensile stress is generated in the portion of the raw metal sheet S corresponding to the concavely curved vertical wall portion 12 during the forming process as it is stretched in the width direction, and this tensile stress acts to draw material in from the adjacent portion corresponding to the convexly curved vertical wall portion 22. That is, during the forming process, a material pushing action occurs from the portion of the raw metal sheet S corresponding to the convexly curved vertical wall portion 22 to the portion corresponding to the concavely curved vertical wall portion 12, and a material pulling action occurs in the portion corresponding to the concavely curved vertical wall portion 12 from the portion corresponding to the convexly curved vertical wall portion 22. Due to these actions, material moves from the portion corresponding to the convexly curved vertical wall portion 22 to the portion corresponding to the concavely curved vertical wall portion 12, and the concavely curved vertical wall portion 12 and the convexly curved vertical wall portion 22 are formed. As a result, compared to conventional forming methods, the amount of elongation of the material metal sheet S is reduced at the concavely curved vertical wall portion 12, and the amount of compression is reduced at the convexly curved vertical wall portion 22, thereby suppressing wrinkles.

[0047] Furthermore, because the convex flange portion 24 and the concave flange portion 14 are connected to the convexly curved vertical wall portion 22 and the concavely curved vertical wall portion 12, respectively, during the forming process, material is pushed out along the longitudinal direction of the flange from the portion of the raw metal sheet S that corresponds to the convex flange portion 24 toward the portion that corresponds to the concave flange portion 14, and is deformed so that the material is drawn into the concave flange portion 14. As a result, as with the concavely curved vertical wall portion 12 and the convexly curved vertical wall portion 22, the amount of elongation of the raw metal sheet S is reduced in the concave flange portion 14, and the amount of compression is reduced in the convex flange portion 24, thereby suppressing wrinkles, compared to conventional forming methods.

[0048] As a result, it is possible to satisfactorily form a press-formed product 1 including an S-shaped portion in which a concavely curved portion 10 is continuous with a convexly curved portion 20. In particular, even when a high-strength material with low elongation is used as the base metal plate or when forming a part including an S-shaped portion with a large and sharp curvature, good forming can be achieved.

[0049] In the press forming method according to this embodiment, to prevent wrinkles from forming in the convexly curved vertical wall portion 22, the punch vertical wall surface 112 and the die vertical wall surface 151 shown in FIG. 9 are each parallel to the vertical wall inclination direction V, and the distance between the punch vertical wall surface 112 and the die vertical wall surface 151 during forming must be 1.0 to 1.2 times the thickness of the raw metal sheet S. If the distance is less than 1.0 times the thickness of the raw metal sheet S, the portion of the raw metal sheet S corresponding to the vertical wall portion will be ironed, resulting in defects such as a significant increase in forming load, cracking due to elongation of the material, or warping of the vertical wall portion. Furthermore, if the distance between the punch vertical wall surface 112 and the die vertical wall surface 151 exceeds 1.2 times the thickness of the raw metal sheet S, the amount of material flowing into the portion of the raw metal sheet S corresponding to the convexly curved vertical wall portion 22 within the gap between the punch vertical wall surface 112 and the die vertical wall surface 151 is not sufficiently prevented, and wrinkles are more likely to form in the convexly curved vertical wall portion 22. On the other hand, if press forming is performed while maintaining the distance between the punch vertical wall surface 112 and the die vertical wall surface 151 at 1.0 to 1.2 times the thickness of the raw metal sheet S, ironing of the vertical wall portion does not occur and the occurrence of wrinkles can be suppressed.

[0050] In this embodiment, press forming is performed by lowering the dies 150 and 160 relative to the punch 110 and pad 140, but press forming may also be performed by raising the punch 110 and pad 140 relative to the dies 150 and 160. That is, as with general press forming, from the perspective of realizing press forming in the present disclosure, there are no particular limitations on which of the die and the punch is moved, as long as the die can be moved relatively to the punch and pad.

[0051] Furthermore, the concavely curved portion of the outline of the top plate 2 of the press-formed product 1 may include a straight line portion, and the convexly curved portion may include a straight line portion. For example, in the press-formed product 1 shown in FIG. 11 , the portion from point P1 to point P3 on the outline of the top plate 2 is a concavely curved portion, and this concavely curved portion is composed of a curved portion from point P1 to point P2 and a straight line portion from point P2 to point P3. Furthermore, the portion from point P3 to point P5 on the outline of the top plate 2 is a convexly curved portion, and this convexly curved portion is composed of a straight line portion from point P3 to point P4 and a straight line portion from point P4 to point P5. Note that the line from point P2 to point P4 is a single straight line without a bending point, but in this specification, one straight line portion with the midpoint (half position) of the line as the boundary is considered to be a straight line portion belonging to the concavely curved portion, and the other straight line portion is considered to be a straight line portion belonging to the convexly curved portion. In the example of Figure 11, the midpoint of one straight line is point P3, so as described above, the straight line portion from point P2 to point P3 is a straight line portion included in the concavely curved area, and the straight line portion from point P3 to point P4 is a straight line portion included in the convexly curved area.

[0052] The vertical wall portions connected to the above-mentioned straight portions are non-curved flat portions. From the viewpoint of reducing the deformation resistance due to the presence of these flat portions and facilitating the movement of material from the portion of the base metal sheet S corresponding to the convexly curved vertical wall portion 22 to the portion corresponding to the concavely curved vertical wall portion 12 during the forming process, it is desirable for the straight portions included in the curved portions to be short. Specifically, the length of the straight portion included in the concavely curved portion of the top plate portion 2, i.e., the length of the outline of the top plate portion 2 from point P2 to point P3, is desirably 30% or less of the total length of the concavely curved portion, i.e., the length of the outline of the top plate portion 2 from point P1 to point P3. Furthermore, the length of the straight portion included in the convexly curved portion of the top plate portion 2, i.e., the length of the outline of the top plate portion 2 from point P3 to point P4, is desirably 30% or less of the total length of the convexly curved portion, i.e., the length of the outline of the top plate portion 2 from point P3 to point P5.

[0053] The proportion of straight lines in the concavely curved regions and the proportion of straight lines in the convexly curved regions are preferably 20% or less, and more preferably 10% or less. If these proportions are 0%, i.e., if neither the concavely curved regions nor the convexly curved regions contain straight lines, better molding can be achieved.

[0054] In the press-forming method according to this embodiment, the pressure applied by the pad 140 and the pressure applied by the holders 120 and 130 act in opposite directions, so that the base metal sheet S during forming or demolding is also pressed by the holders 120 and 130 in the opposite direction to the direction of the pressure applied by the pad 140. The positions of the pad 140 and holders 120 and 130 are restricted by the punch 110 and die 150 until the dies 150 and 160 move to the bottom dead center of the press. Meanwhile, during demolding, the pad 140 and holders 120 and 130 apply a crushing force to the pressed panel, which can cause deformation of the pressed panel as shown in FIGS. 9A to 9C of Japanese Patent No. 6098727.

[0055] Therefore, after the die 150 is moved to the press bottom dead center to form the concave curved vertical wall portion 12 and the convex curved vertical wall portion 22, when demolding, it is desirable to remove the press panel from the mold while maintaining the distance between the pad 140 and the holders 120, 130 in the press direction (vertical direction) at least 0.95 times the distance between the pad 140 and the holders 120, 130 in the press direction at the end of molding.

[0056] Second Embodiment Next, a method for manufacturing the press-formed product 1 according to the second embodiment will be described. Note that the description of the same content as in the first embodiment may be omitted.

[0057] FIG. 12 is a diagram showing a schematic configuration of a press-formed product 1 and a press forming apparatus 100 according to a second embodiment. Like the vertical wall portion on side A illustrated in FIG. 12(a), the press-formed product 1 may have a plurality of S-shaped portions in which a concavely curved portion and a convexly curved portion are continuous. Furthermore, as illustrated in FIG. 12(a), the S-shaped curvature may be provided not only on side A but also on side B. Furthermore, the angle formed between the top plate portion 2 and the A-side vertical wall portion and the angle formed between the top plate portion 2 and the B-side vertical wall portion may be the same or different.

[0058] A press-formed product 1 having S-shaped curved portions on both sides A and B is manufactured, for example, by a press forming apparatus 100 shown in Fig. 12(b). In the press forming apparatus 100, the vertical wall surface on the A side of the punch 115 and the vertical wall surface of the die 152 have shapes corresponding to the A-side vertical wall portion of the press-formed product 1, and the vertical wall surface on the B side of the punch 115 and the vertical wall surface of the die 161 have shapes corresponding to the B-side vertical wall portion of the press-formed product 1.

[0059] Figure 13 is a diagram showing the state of the raw metal sheet in relation to the operation of the press-forming device in the a1-a2 cross section shown in Figure 12(a). Figure 13(a) shows the initial state of forming, Figure 13(a) shows the state during forming, and Figure 13(c) shows the state after forming is completed. The white arrows in the figure indicate the direction of the pressure applied to holders 121, 131 and pad 140, and the black arrows in the figure indicate the direction of movement of dies 152, 161.

[0060] The vertical wall portion on side A is formed by, with the raw metal sheet S sandwiched between the holder 121 and the die 152, moving the die 152 relative to the punch 115 and the pad 140 along the inclination direction V1 of the vertical wall on side A. On the other hand, the vertical wall portion on side B is formed by, with the raw metal sheet S sandwiched between the holder 131 and the die 161, moving the die 161 relative to the punch 115 and the pad 140 along the inclination direction V2 of the vertical wall on side B. As a result, during the forming process, on both sides A and B, material moves from the portions of the raw metal sheet S that correspond to the convexly curved vertical wall portions to the portions that correspond to the concavely curved vertical wall portions, as in the first embodiment, allowing for good forming.

[0061] As in the second embodiment described above, even if there are multiple S-shaped curved portions or if they exist on both sides A and B, good molding can be achieved by moving the die along the specific vertical wall inclination direction of each S-shaped portion (V1 and V2 in this embodiment).

[0062] Third Embodiment Next, a method for manufacturing the press-formed product 1 according to the third embodiment will be described. Note that the description of the same content as in the first and second embodiments may be omitted.

[0063] Fig. 14 is a diagram showing a press-formed product 1 according to a third embodiment. The press-formed product 1 illustrated here does not have the S-shaped curved portion described in the first and second embodiments, but this press-formed product 1 is manufactured from a press-formed product 1a as an intermediate product shown in Fig. 15. The press-formed product 1a has an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuous, and therefore the press-formed product 1a can be formed by using the press forming method described in the first and second embodiments.

[0064] As shown in Fig. 16(a), a press-forming apparatus 100 for forming a press-formed product 1a as an intermediate product is composed of components such as a punch 116, holders 122 and 130, a pad 141, and dies 153 and 160, similar to the apparatus configuration described in the above embodiment. Also, as shown in Fig. 16(b), the punch 116 has a punch vertical wall surface 117 for forming the concavely curved vertical wall portion and the convexly curved vertical wall portion of the press-formed product 1a. The punch vertical wall surface 117 includes a concavely curved surface and a convexly curved surface, and extends parallel to the vertical wall inclination direction V.

[0065] When forming the press-formed product 1a, the portion of the base metal plate corresponding to the top plate portion 2 is clamped between the punch 116 and the pad 141, and the remaining portion is clamped between the holders 122, 130 and the dies 153, 160. Describing the holder 122 and the die 153 on the S-shaped portion side in detail, at least a portion of the portion of the base metal plate corresponding to the concavely curved vertical wall portion 12, the concave flange ridge portion 13, the concave flange portion 14, and the convexly curved vertical wall portion 22 is clamped between the holder 122 and the die 153. Next, the die 153 is moved relative to the punch 116 and the pad 141 along the vertical wall inclination direction V, and the die 160 is moved relative to the punch 116 and the pad 141 along the vertical direction, thereby forming the press-formed product 1a.

[0066] Then, by cutting the convex top plate ridge portion 21 and the convex curved vertical wall portion 22 of the press-formed product 1a as an intermediate product shown in Figure 15, it is possible to manufacture the press-formed product 1 as a finished product including the concave curved portion 10 composed of the concave curved vertical wall portion 12 and the concave flange portion 14 as shown in Figure 14.

[0067] 14 directly from a base metal sheet, depending on the forming method, the flow of material from the portion of the base metal sheet corresponding to the top plate portion 2 to the portion corresponding to the concavely curved vertical wall portion 12 may be reduced, increasing the amount of elongation of the material in the concavely curved vertical wall portion 12 and causing cracks. On the other hand, in the press-forming method according to the third embodiment, when forming the press-formed product 1a as an intermediate product, it is possible to promote the flow of material from the portion of the base metal sheet corresponding to the convexly curved vertical wall portion 22 to the portion corresponding to the concavely curved vertical wall portion 12. As a result, the amount of elongation of the material in the concavely curved vertical wall portion 12 is reduced, and the occurrence of cracks can be suppressed.

[0068] The press-formed product 1a serving as an intermediate product exemplified in Fig. 15 may have a plurality of S-shaped portions. In that case, the press-formed product 1a includes a plurality of convex top ridge portions 21 and convexly curved vertical wall portions 22, and by cutting these convex top ridge portions 21 and convexly curved vertical wall portions 22, it is also possible to manufacture a press-formed product having a shape different from that of the press-formed product 1 exemplified in Fig. 15.

[0069] 15 does not have a convex flange portion, the press-formed product 1a as an intermediate product may have a convex flange portion formed therein. In this case, the press-formed product 1 as a finished product can be manufactured by cutting off the convex top plate ridge portion 21, the convexly curved vertical wall portion 22, and the convex flange portion.

[0070] While the present invention has been described above by way of example, it is understood that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and that such modifications and alterations are also within the technical scope of the present invention.

[0071] For example, the components of the above-described embodiments can be combined in any manner, and such combinations will naturally provide the functions and advantages of the individual components involved in the combination, as well as other functions and advantages that will be apparent to those skilled in the art from the description herein. [Example]

[0072] Examples and comparative examples of the present invention will be described below.

[0073] In Examples 1 to 11, a press-formed product 1 including an S-shaped curved portion measuring 500 mm in length, 260 mm in width, and 60 mm in height, as shown in FIG. 17, was produced by press-forming a base metal sheet S having a length of 560 mm and a width of 442 mm, as shown in FIG. 18, to obtain a pressed panel. The concavely curved and convexly curved portions of the outline of the top panel 2 shown in FIG. 17 do not include straight lines. Furthermore, the base metal sheet S shown in FIG. 18 is shaped so that the pressed panel is slightly larger than the product shape after pressing. If the pressed panel can be formed without cracking, the excess portion of the pressed panel can be cut off to obtain a part with the product shape. Furthermore, in the forming examples corresponding to the examples of the present invention, the punch and holder, and the die and pad are separated from each other after press-forming while ensuring that the distance between the punch and die and the distance between the pad and holder are not shorter than the respective distances at the end of forming, and then the pressed panel is removed from the press-forming apparatus.

[0074] (Forming Example 1) Comparative Example (Drawing) In Forming Example 1, a steel plate having a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate, and the base metal plate was subjected to drawing using a press forming device 60 consisting of a die 64, holders 62 and 63, and a punch 61 shown in Figure 19 to obtain a pressed panel. As a result, wrinkles occurred in the convexly curved vertical wall portion 22 and the convex flange portion 24 of the pressed panel, and cracks occurred in the concave flange portion 14, making it impossible to obtain a good pressed panel.

[0075] (Molding Example 2) Comparative Example (Foam Molding) In Forming Example 2, a steel plate having a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate, and the base metal plate was formed into a pressed panel using a press forming device 60 consisting of a die 64 and a punch 65 shown in Figure 20. As a result, wrinkles occurred in the convexly curved vertical wall portion 22 and the convex flange portion 24 of the pressed panel, and cracks occurred in the concave flange portion 14, making it impossible to obtain a good pressed panel.

[0076] (Molding Example 3) Example In Forming Example 3, a steel sheet having a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal sheet. The base metal sheet was press-formed using the press-forming method shown in FIG. 22 using a press-forming apparatus 100 including dies 150 and 160, holders 120 and 130, pad 140, and punch 110 shown in FIG. 21, to obtain a pressed panel. Figure 22(a) shows the initial state of forming, Figure 22(b) shows the state during forming, and Figure 22(c) shows the state after forming is completed. The open arrows in FIG. 22 indicate the direction of the pressure applied to the holders 120 and 130, and the filled arrows in FIG. 22 indicate the direction of movement of the dies 150 and 160. In Forming Example 3, the die 150 was moved along the vertical wall inclination direction V during the forming process while maintaining the distance between the vertical wall surface of the die 150 and the vertical wall surface of the punch 110 at 1.0 times the thickness of the base metal sheet. As a result, a good pressed panel without wrinkles or cracks was obtained.

[0077] (Molding Example 4) Example In forming example 4, a steel plate having a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate, and the base metal plate was press-formed using the press-forming method shown in Figure 24 using a press-forming apparatus 100 consisting of dies 154, 160, holders 123, 130, pad 140, and punch 118 shown in Figure 23, to obtain a pressed panel. Figure 24(a) shows the initial state of forming, Figure 24(b) shows the state during forming, and Figure 24(c) shows the state after forming. The white arrows in Figure 24 indicate the direction of the pressure applied to the holders 123, 130, and the black arrows in Figure 24 indicate the direction of movement of the dies 154, 160. In Forming Example 4, during the forming process, the die 154 was moved along the vertical wall inclination direction V while maintaining the distance between the vertical wall surface of the die 154 and the vertical wall surface of the punch 118 at 1.0 times the thickness of the base metal sheet, but the holder 123 was moved in a direction perpendicular to the top plate portion. As a result, a good pressed panel without wrinkles or cracks was obtained. As shown in Forming Example 4, the holder facing the die, including the vertical wall surface of the die for forming the S-shaped vertical wall portion, does not necessarily need to be moved in the vertical wall inclination direction, as long as it can maintain a state in which it clamps a portion of the base metal sheet as the die moves.

[0078] (Molding Example 5) Example In Forming Example 5, a steel plate with a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate. The base metal plate was press-formed using the press-forming method shown in FIG. 22 using a press-forming apparatus 100 consisting of dies 150 and 160, holders 120 and 130, pad 140, and punch 110 shown in FIG. 21, to obtain a pressed panel. The forming conditions and operation of the press-forming apparatus 100 in Forming Example 5 were almost the same as those in Forming Example 3, except that the distance between the vertical wall surface of the die including the S-shaped portion and the vertical wall surface of the punch including the S-shaped portion during the forming process was maintained at 1.1 times the thickness of the base metal plate. Forming Example 5 produced a good pressed panel free of wrinkles and cracks.

[0079] (Molding Example 6) Example In Forming Example 6, a steel plate with a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate. The base metal plate was press-formed by the press-forming method shown in FIG. 22 using a press-forming apparatus 100 consisting of dies 150 and 160, holders 120 and 130, pad 140, and punch 110 shown in FIG. 21, to obtain a pressed panel. The forming conditions and operation of the press-forming apparatus 100 in Forming Example 6 were almost the same as those in Forming Example 3, except that the distance between the vertical wall surface of the die including the S-shaped portion and the vertical wall surface of the punch including the S-shaped portion during the forming process was maintained at 1.2 times the thickness of the base metal plate. Forming Example 6 produced a good pressed panel free of wrinkles and cracks.

[0080] (Molding Example 7) Comparative Example In Forming Example 7, a steel plate having a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate. The base metal plate was press-formed by the press-forming method shown in FIG. 22 using a press-forming apparatus 100 including dies 150 and 160, holders 120 and 130, pad 140, and punch 110 shown in FIG. 21 to obtain a pressed panel. The forming conditions and operation of the press-forming apparatus 100 in Forming Example 7 were essentially the same as those in Forming Example 3, except that the distance between the vertical wall surface of the die including the S-shaped portion and the vertical wall surface of the punch including the S-shaped portion was maintained at 1.5 times the thickness of the base metal plate during the forming process. In Forming Example 7, wrinkles occurred in the convexly curved vertical wall portion 22 and the convex flange portion 24 of the pressed panel, and a good pressed panel could not be obtained.

[0081] (Molding Example 8) Comparative Example In Forming Example 8, a steel plate having a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate. The base metal plate was press-formed by the press-forming method shown in FIG. 22 using a press-forming apparatus 100 including dies 150 and 160, holders 120 and 130, a pad 140, and a punch 110 shown in FIG. 21 to obtain a pressed panel. The forming conditions and operation of the press-forming apparatus 100 in Forming Example 8 were essentially the same as those in Forming Example 3, except that the distance between the vertical wall surface of the die including the S-shaped portion and the vertical wall surface of the punch including the S-shaped portion was maintained at 2.0 times the thickness of the base metal plate during the forming process. In Forming Example 8, wrinkles occurred in the convexly curved vertical wall portion 22 and the convex flange portion 24 of the pressed panel, and cracks occurred in the concave flange portion 14, making it impossible to obtain a satisfactory pressed panel.

[0082] (Molding Example 9) Comparative Example In Forming Example 9, a steel plate having a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate. The base metal plate was press-formed by the press-forming method shown in FIG. 22 using a press-forming apparatus 100 including dies 150 and 160, holders 120 and 130, a pad 140, and a punch 110 shown in FIG. 21 to obtain a pressed panel. The forming conditions and operation of the press-forming apparatus 100 in Forming Example 9 were almost the same as those in Forming Example 3, except that the distance between the vertical wall surface of the die including the S-shaped portion and the vertical wall surface of the punch including the S-shaped portion was maintained at 0.8 times the thickness of the base metal plate during the forming process. In Forming Example 9, cracks occurred in the convexly curved vertical wall portion 22 of the pressed panel, and a good pressed panel could not be obtained.

[0083] (Molding Example 10) Example In Forming Example 10, a steel plate having a tensile strength of 1180 MPa and a thickness of 1.6 mm was used as the base metal plate. The base metal plate was press-formed using the press-forming method shown in FIG. 22 using a press-forming apparatus 100 shown in FIG. 21, which was comprised of dies 150 and 160, holders 120 and 130, pad 140, and punch 110. A pressed panel was obtained. In Forming Example 10, the press-forming was performed while maintaining the distance between the vertical wall surface of the die, including the S-shaped portion, and the vertical wall surface of the punch, including the S-shaped portion, at 1.1 times the thickness of the base metal plate. In Forming Example 10, a good pressed panel without wrinkles or cracks was obtained.

[0084] (Molding Example 11) Example In Forming Example 11, an aluminum alloy plate having a tensile strength of 270 MPa and a thickness of 1.2 mm was used as the base metal plate. The base metal plate was press-formed using the press-forming method shown in FIG. 22 using a press-forming apparatus 100 including dies 150 and 160, holders 120 and 130, pad 140, and punch 110 shown in FIG. 21, to obtain a pressed panel. In Forming Example 11, press-forming was performed while maintaining the distance between the vertical wall surface of the die including the S-shaped portion and the vertical wall surface of the punch including the S-shaped portion at 1.0 times the thickness of the base metal plate. In Forming Example 11, a good pressed panel without wrinkles or cracks was obtained.

[0085] (Molding Example 12) Example In Forming Example 12, a press panel was obtained by press-forming a base metal plate to produce the press-formed product 1 shown in FIG. 25 , which includes an S-shaped curved portion measuring 500 mm in length, 260 mm in width, and 60 mm in height. The concavely curved portion of the outline of the top plate 2 shown in FIG. 25 includes a straight line, and the length of that straight line (the length from point P2 to point P3) is 13% of the total length of the concavely curved portion (the length from point P1 to point P3). The convexly curved portion of the outline of the top plate 2 also includes a straight line, and the length of that straight line (the length from point P3 to point P4) is 13% of the total length of the convexly curved portion (the length from point P3 to point P5). The base metal plate was shaped so that the pressed panel would be slightly larger than the product shape after pressing. If the pressed panel could be formed without cracking, the excess portion of the pressed panel could be cut off to obtain a part with the product shape. After press molding, the punch and holder, and the die and pad are separated from each other while ensuring that the distance between the punch and die and the distance between the pad and holder are not shorter than the respective distances at the end of molding, and then the press panel is removed from the press molding device.

[0086] In Forming Example 12, a steel plate with a tensile strength of 980 MPa and a thickness of 1.2 mm was used as the base metal plate. The base metal plate was formed using a press-forming apparatus according to the press-forming method shown in FIG. 22 to obtain a pressed panel. The press-forming apparatus in Forming Example 12 was similar in configuration to the press-forming apparatus 100 used in Forming Example 3 shown in FIG. 21, but the punch vertical wall surface including the S-shaped portion and the die vertical wall surface including the S-shaped portion had shapes corresponding to the S-shaped portion of the press-formed product 1 shown in FIG. 25. In Forming Example 12, during the forming process, the die was moved along the inclination direction of the vertical wall while maintaining the distance between the die vertical wall surface including the S-shaped portion and the punch vertical wall surface including the S-shaped portion at 1.0 times the thickness of the base metal plate. As a result, a good pressed panel without wrinkles or cracks was obtained.

[0087] (Molding Example 13) Example In Forming Example 13, a press panel was obtained by press-forming a base metal sheet to produce the press-formed product 1 shown in FIG. 26 , which includes an S-shaped curved portion having a length of 500 mm, a width of 260 mm, and a height of 60 mm. The concavely curved portion of the outline of the top plate portion 2 shown in FIG. 26 includes a straight line, and the length of that straight line (the length from point P2 to point P3) is 40% of the total length of the concavely curved portion (the length from point P1 to point P3). The convexly curved portion of the outline of the top plate portion 2 also includes a straight line, and the length of that straight line (the length from point P3 to point P4) is 40% of the total length of the convexly curved portion (the length from point P3 to point P5). The forming conditions and the configuration of the press-forming apparatus in Forming Example 13 were almost the same as those in Forming Example 12, but differed from Forming Example 12 in that the S-shaped die vertical wall surface and the S-shaped punch vertical wall surface had shapes corresponding to the press-formed product 1 shown in FIG. 26 .

[0088] Under the molding conditions of this Molding Example 13, cracks occurred in the concave flange portion of the press panel, but no cracks occurred in the concavely curved vertical wall portion, and no wrinkles occurred in the convexly curved vertical wall portion, so a better press panel was obtained compared to when press molding was performed using a conventional press molding method. However, from the perspective of obtaining an even better press panel, as in the above-mentioned Molding Example 12, it is desirable that the proportion of straight lines included in the concavely curved portion of the outline of the top plate portion 2 and the proportion of straight lines included in the convexly curved portion are each 30% or less.

[0089] (Molding Example 14) Example In Forming Example 14, a press-formed panel was obtained by press-forming a 560 mm long, 470 mm wide metal plate to produce a press-formed product 1, shown in Figures 27(a) and 27(b), which has a roughly hat-shaped shape with multiple S-shaped sections, measuring 500 mm in length, 280 mm in width, and 60 mm in height. Figures 27(a) and 27(b) show the same press-formed product 1 from different perspectives. This press-formed product 1 has vertical wall sections and flange sections connected to the vertical walls on both sides of the top panel. As shown in Figure 27, the vertical wall section on side A includes multiple S-shaped sections, and the vertical wall section on side B includes one S-shaped section. The inclination directions of the concavely curved vertical wall and the convexly curved vertical wall sections of the multiple S-shaped sections on side A are all the same, as indicated by V1 in Figure 27. The inclination directions of the concavely curved vertical wall and the convexly curved vertical wall sections on side B are the same, as indicated by V2 in Figure 27.

[0090] The press forming of the raw metal plate was carried out by the press forming method shown in Figure 29 using a press forming apparatus 100 consisting of punch 115, pad 140, A-side holder 121, A-side die 152, B-side holder 131, and B-side die 161 shown in Figure 28. Figure 29(a) shows the initial state of forming, Figure 29(b) shows the state during forming, and Figure 29(c) shows the state after forming has finished. The white arrows in Figure 29 indicate the direction of the pressure applied to holders 121 and 131, and the black arrows in Figure 29 indicate the direction of movement of dies 152 and 161. In Forming Example 14, press forming was performed by moving the A-side die 152 along the vertical wall inclination direction V1 and the B-side die 161 along the vertical wall inclination direction V2 while maintaining the distance between the vertical wall surface of the A-side die 152 and the vertical wall surface of the punch 110 and the distance between the vertical wall surface of the B-side die 161 and the vertical wall surface of the punch 110 at 1.0 times the thickness of the base metal sheet S. As a result, a good pressed panel without wrinkles or cracks was obtained.

[0091] (Forming Example 15) Comparative Example (Bending Forming) In Example 15, a press-formed product 1 having a generally hat-shaped shape with a length of 1500 mm, a width of 240 mm, and a height of 84 mm, as shown in FIG. 30, and having two concavely curved portions, was obtained by press-forming a base metal sheet using a press-forming device 60 including a punch 66, a pad 67, and dies 68 and 69, as shown in FIG. 31. Specifically, the base metal sheet was clamped between the punch 66 and the pad 67, and the dies 68 and 69 were moved to pad-bend the vertical wall portion and flange portion. The convexly curved portion was then cut off to obtain a pressed panel. In Example 15, cracks occurred in both of the two concave flange portions 14, and a satisfactory pressed panel could not be obtained.

[0092] To form the two concave curved portions shown in Fig. 30, it is necessary to flow material in the direction of the arrows shown in Fig. 32. That is, to form the two concave curved portions, it is necessary to move material in two opposite directions from the top plate portion, but such movement of material is difficult to achieve in pad bending forming such as in Forming Example 15. For this reason, cracks occurred in concave flange portion 14 in Forming Example 15.

[0093] (Molding Example 16) Example In Example 16, similar to Example 15, a press-formed product 1 shown in FIG. 30 was produced by press-forming a base metal plate using a press-forming apparatus 100 including a punch 116, holders 122 and 130, a pad 141, and dies 153 and 160 shown in FIG. 33. As shown in FIG. 33(b), the punch 116 has a punch vertical wall surface 117 for forming the vertical wall portion of the press-formed product 1. This punch vertical wall surface 117 includes two concavely curved concave surfaces and a convexly curved convex surface located between and connected to the concavely curved surfaces. The punch vertical wall surface 117 is also a surface parallel to the vertical wall inclination direction V of the concavely curved vertical wall portion 12 of the press-formed product 1 shown in FIG. 30. Press-forming using the press-forming apparatus 100 described above is performed as follows.

[0094] First, a portion of the base metal sheet corresponding to the top plate portion 2 of the press-formed product 1 was clamped and restrained between the punch 116 and pad 141, while the remaining portion of the base metal sheet was clamped between the holders 122, 130 and the dies 153, 160. Next, the die 153 was moved along the vertical wall inclination direction V while maintaining the distance between the punch vertical wall surface 117, including the concavely curved surface and the die vertical wall surface having a shape corresponding to the punch vertical wall surface 117, at 1.0 times the thickness of the base metal sheet. Meanwhile, the die 160 was moved vertically downward. This resulted in a pressed panel as an intermediate product shown in Figure 34, which was free of cracks and wrinkles and had a good shape. The convex top plate ridge and convexly curved vertical wall portions of the pressed panel were then cut to obtain the finished pressed panel shown in Figure 30. The finished pressed panel also showed no cracks in the concavely curved vertical wall portion 12 or the concave flange portion 14.

[0095] The above describes embodiments of the present invention. The effects described herein are merely illustrative or exemplary and are not limiting. In other words, the technology disclosed herein may achieve other effects that will be apparent to those skilled in the art from the description of this specification, in addition to or in place of the above effects.

[0096] Note that the following configuration examples also fall within the technical scope of the present disclosure. (1) A top plate portion having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of the outline; a concave top ridge portion connected to the concavely curved portion of the top portion; a convex top ridge portion connected to the convexly curved portion of the top portion; a concave curved vertical wall portion connected to the concave top plate ridge line portion on the opposite side to the top plate portion side; a convex curved vertical wall portion connected to the convex top plate ridge line portion on the opposite side to the top plate portion side; a concave flange ridge line portion connected to the concave curved vertical wall portion on the opposite side from the concave top plate ridge line portion side; a convex flange ridge portion connected to the convex curved vertical wall portion on the opposite side from the convex top plate ridge portion side; a concave flange portion connected to the concave flange ridge line portion on the opposite side to the concave curved vertical wall portion; a convex flange portion connected to the convex flange ridge line portion on the opposite side to the convexly curved vertical wall portion, and wherein an angle formed by the top plate portion and the concavely curved vertical wall portion and an angle formed by the top plate portion and the convexly curved vertical wall portion are each greater than 90 degrees, A press molding apparatus including a punch, a holder disposed on the side of the punch, a pad disposed opposite the punch, and a die disposed opposite the holder is used, the punch includes punch vertical wall surfaces that correspond to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively, and are parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, the die includes die vertical wall surfaces parallel to the vertical wall inclination direction, the die vertical wall surfaces corresponding to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively; When manufacturing the press-formed product from a base metal plate, At least a part of a portion of the top plate portion of the material metal plate corresponding to the S-shaped portion is clamped and restrained by the punch and the pad, at least a part of a portion of the base metal plate corresponding to the concavely curved vertical wall portion, the concave flange ridge portion, the concave flange portion, the convexly curved vertical wall portion, the convex flange ridge portion, and the convex flange portion is clamped between the holder and the die; a method for manufacturing a press-formed product, characterized in that the die is moved relative to the punch and the pad along a vertical wall inclination direction while maintaining a distance between the punch vertical wall surface and the die vertical wall surface to be 1.0 to 1.2 times the plate thickness of the base metal plate, thereby forming the concavely curved vertical wall portion and the convexly curved vertical wall portion, thereby manufacturing the press-formed product. (2) The length of the straight line portion included in the concavely curved portion of the top plate portion is 30% or less of the total length of the outline of the concavely curved portion, A method for manufacturing a press-molded product as described in (1), characterized in that the length of the straight portion included in the convexly curved portion of the top plate portion is 30% or less of the total length of the outline of the convexly curved portion. (3) The press-molded product has a plurality of the S-shaped portions, A method for manufacturing a press-molded product according to (1) or (2), characterized in that the concavely curved vertical wall portion and the convexly curved vertical wall portion corresponding to each S-shaped portion are formed by moving the die relative to the punch and the pad along the inclination direction of the vertical wall specific to each S-shaped portion. (4) After producing the press-formed product including the concavely curved vertical wall portion and the convexly curved vertical wall portion, The method for manufacturing a press-molded product according to any one of (1) to (3), characterized in that the convex top plate ridge portion, the convexly curved vertical wall portion, the convex flange ridge portion, and the convex flange portion are cut to manufacture a press-molded product including the top plate portion, the concave top plate ridge portion, the concavely curved vertical wall portion, the concave flange ridge portion, and the concave flange portion. (5) The method for producing a press-formed product according to any one of (1) to (4), wherein the base metal plate has a tensile strength of 500 MPa or more. (6) After forming the concavely curved vertical wall portion and the convexly curved vertical wall portion, A method for manufacturing a press-molded product according to any one of (1) to (5), characterized in that the press-molded product is removed from the press molding apparatus while maintaining the distance between the pad and the holder in the press direction at a state where it is not less than 0.95 times the distance between the pad and the holder in the press direction at the end of molding. (7) A method for producing a press-formed product as an intermediate product by press-forming a raw metal plate, and producing a press-formed product as a finished product from the intermediate product, The first half intermediate products are a top plate portion having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of the outline; a concave top ridge portion connected to the concavely curved portion of the top portion; a convex top ridge portion connected to the convexly curved portion of the top portion; a concave curved vertical wall portion connected to the concave top plate ridge line portion on the opposite side to the top plate portion side; a convex curved vertical wall portion connected to the convex top plate ridge line portion on the opposite side to the top plate portion side; a concave flange ridge line portion connected to the concave curved vertical wall portion on the opposite side from the concave top plate ridge line portion side; a concave flange portion connected to the concave flange ridge line portion on the opposite side to the concave curved vertical wall portion side, and the angle formed by the top plate portion and the concave curved vertical wall portion and the angle formed by the top plate portion and the convex curved vertical wall portion are each greater than 90 degrees, When manufacturing the intermediate product, A press molding apparatus including a punch, a holder disposed on the side of the punch, a pad disposed opposite the punch, and a die disposed opposite the holder is used, the punch includes punch vertical wall surfaces that correspond to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively, and are parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, the die includes die vertical wall surfaces parallel to the vertical wall inclination direction, the die vertical wall surfaces corresponding to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively; At least a part of a portion of the top plate portion of the material metal plate corresponding to the S-shaped portion is clamped and restrained by the punch and the pad, at least a part of a portion of the base metal plate corresponding to the concavely curved vertical wall portion, the concave flange ridge portion, the concave flange portion, and the convexly curved vertical wall portion is clamped between the holder and the die; While maintaining a distance between the punch vertical wall surface and the die vertical wall surface at 1.0 to 1.2 times the thickness of the base metal plate, the die is moved relative to the punch and the pad along the vertical wall inclination direction, thereby forming the concavely curved vertical wall portion and the convexly curved vertical wall portion to manufacture the intermediate product; A method for manufacturing a press-molded product, characterized in that the convex top plate ridge portion and the convex curved vertical wall portion of the intermediate product are cut to produce a press-molded product including the top plate portion, the concave top plate ridge portion, the concave curved vertical wall portion, the concave flange ridge portion, and the concave flange portion. (8) The length of the straight line portion included in the concavely curved portion of the top plate portion of the intermediate product is 30% or less of the total length of the outline of the concavely curved portion, The method for manufacturing a press-molded product described in (7) is characterized in that the length of the straight portion included in the convexly curved portion of the top plate portion of the intermediate product is 30% or less of the total length of the outline of the convexly curved portion. (9) The intermediate product has a plurality of the S-shaped portions, A method for manufacturing a press-molded product according to (7) or (8), characterized in that the concavely curved vertical wall portion and the convexly curved vertical wall portion corresponding to each S-shaped portion are formed by moving the die relative to the punch and the pad along the vertical wall inclination direction specific to each S-shaped portion. (10) The method for producing a press-formed product according to any one of (7) to (9), wherein the base metal plate has a tensile strength of 500 MPa or more. (11) After forming the concavely curved vertical wall portion and the convexly curved vertical wall portion, A method for manufacturing a press-molded product according to any one of (7) to (10), characterized in that the intermediate product is removed from the press molding apparatus while maintaining the distance between the pad and the holder in the press direction at a state not less than 0.95 times the distance between the pad and the holder in the press direction at the end of molding. [Industrial Applicability]

[0097] The present invention can be applied to the manufacture of press-formed products having shapes in which the outline of the top plate and the vertical wall portions include both concavely curved portions and convexly curved portions. [Explanation of symbols]

[0098] 1 Press-molded products 2 Top plate 3 Vertical wall section 4 Flange 10 Concave curved area 11 Concave top plate ridge 12 Concave curved vertical wall 13 Concave flange ridge 14 Concave flange 20 Convex curved area 21 Convex top plate ridge 22 Convex curved vertical wall 23 Convex flange ridge 24 Convex flange 51 Top plate 52 Vertical wall section 53 Flange 54, 55 Ridge 60 Conventional press forming equipment 61 Punch 62, 63 Holder 64 Die 65, 66 punches 100 Press forming equipment 110 Punch 111 Punch top surface 112 Punch vertical wall 113 Punch vertical wall 114 Vertical Plane 115, 116 punches 117 Punch vertical wall 118 Punch 120, 121, 122, 123, 130, 131 holders 140, 141 Pads 150 Dies 151 Die vertical wall 152, 153, 154, 160, 161 Dies S Material Metal Plate V Vertical wall inclination direction V1 vertical wall inclination direction V2 vertical wall inclination direction

Claims

1. a top plate portion having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of its outline; a concave top ridge portion connected to the concavely curved portion of the top portion; a convex top ridge portion connected to the convexly curved portion of the top portion; a concave curved vertical wall portion connected to the concave top plate ridge line portion on the opposite side to the top plate portion side; a convex curved vertical wall portion connected to the convex top plate ridge line portion on the opposite side to the top plate portion side; a concave flange ridge line portion connected to the concave curved vertical wall portion on the opposite side from the concave top plate ridge line portion side; a convex flange ridge portion connected to the convex curved vertical wall portion on the opposite side from the convex top plate ridge portion side; a concave flange portion connected to the concave flange ridge line portion on the opposite side to the concave curved vertical wall portion; a convex flange portion connected to the convex flange ridge line portion on an opposite side to the convexly curved vertical wall portion, and wherein an angle formed by the top plate portion and the concavely curved vertical wall portion and an angle formed by the top plate portion and the convexly curved vertical wall portion are each greater than 90 degrees, A press molding apparatus including a punch, a holder disposed on the side of the punch, a pad disposed opposite the punch, and a die disposed opposite the holder is used, the punch includes punch vertical wall surfaces that correspond to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively, and are parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, the die includes die vertical wall surfaces parallel to the vertical wall inclination direction, the die vertical wall surfaces corresponding to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively; When manufacturing the press-formed product from a base metal plate, At least a part of a portion of the top plate portion of the material metal plate corresponding to the S-shaped portion is clamped and restrained by the punch and the pad, at least a part of a portion of the base metal plate corresponding to the concavely curved vertical wall portion, the concave flange ridge portion, the concave flange portion, the convexly curved vertical wall portion, the convex flange ridge portion, and the convex flange portion is clamped between the holder and the die; a method for manufacturing a press-formed product, characterized in that the die is moved relative to the punch and the pad along the vertical wall inclination direction while maintaining the distance between the punch vertical wall surface and the die vertical wall surface to be 1.0 to 1.2 times the plate thickness of the material metal plate, thereby forming the concavely curved vertical wall portion and the convexly curved vertical wall portion, thereby manufacturing the press-formed product.

2. the length of the straight line portion included in the concavely curved portion of the top plate portion is 30% or less of the total length of the outline of the concavely curved portion, 2. The method for manufacturing a press-formed product according to claim 1, wherein the length of the straight line portion included in the convexly curved portion of the top plate portion is 30% or less of the total length of the outline of the convexly curved portion.

3. The press-formed product has a plurality of the S-shaped portions, 2. The method for manufacturing a press-formed product according to claim 1, characterized in that the concavely curved vertical wall portion and the convexly curved vertical wall portion corresponding to each S-shaped portion are formed by moving the die relative to the punch and the pad along the vertical wall inclination direction specific to each S-shaped portion.

4. After manufacturing the press-formed product including the concavely curved vertical wall portion and the convexly curved vertical wall portion, The method for manufacturing a press-formed product according to any one of claims 1 to 3, characterized in that the press-formed product is manufactured by cutting the convex top plate ridge portion, the convexly curved vertical wall portion, the convex flange ridge portion, and the convex flange portion, and including the top plate portion, the concave top plate ridge portion, the concavely curved vertical wall portion, the concave flange ridge portion, and the concave flange portion.

5. The method for manufacturing a press-formed product according to any one of claims 1 to 3, wherein the base metal plate has a tensile strength of 500 MPa or more.

6. After forming the concavely curved vertical wall portion and the convexly curved vertical wall portion, The press-formed product is removed from the press forming apparatus while maintaining a distance between the pad and the holder in the press direction that is not less than 0.95 times the distance between the pad and the holder in the press direction at the end of forming. The method for manufacturing a press-formed product according to any one of claims 1 to 3,

7. A method for producing a press-formed product as an intermediate product by press-forming a raw metal plate, and producing a press-formed product as a finished product from the intermediate product, comprising: The first half intermediate products are a top plate portion having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of its outline; a concave top ridge portion connected to the concavely curved portion of the top portion; a convex top ridge portion connected to the convexly curved portion of the top portion; a concave curved vertical wall portion connected to the concave top plate ridge line portion on the opposite side to the top plate portion side; a convex curved vertical wall portion connected to the convex top plate ridge line portion on the opposite side to the top plate portion side; a concave flange ridge line portion connected to the concave curved vertical wall portion on the opposite side from the concave top plate ridge line portion side; a concave flange portion connected to the concave flange ridge line portion on the opposite side to the concave curved vertical wall portion side, and an angle formed by the top plate portion and the concave curved vertical wall portion and an angle formed by the top plate portion and the convex curved vertical wall portion are each greater than 90 degrees, When manufacturing the intermediate product, A press molding apparatus including a punch, a holder disposed on the side of the punch, a pad disposed opposite the punch, and a die disposed opposite the holder is used, the punch includes punch vertical wall surfaces that correspond to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively, and are parallel to the inclination directions of the concavely curved vertical wall portion and the convexly curved vertical wall portion, the die includes die vertical wall surfaces parallel to the vertical wall inclination direction, the die vertical wall surfaces corresponding to the shapes of the concavely curved vertical wall portion and the convexly curved vertical wall portion, respectively; At least a part of a portion of the top plate portion of the material metal plate corresponding to the S-shaped portion is clamped and restrained by the punch and the pad, at least a part of a portion of the base metal plate corresponding to the concavely curved vertical wall portion, the concave flange ridge portion, the concave flange portion, and the convexly curved vertical wall portion is clamped between the holder and the die; While maintaining a distance between the punch vertical wall surface and the die vertical wall surface to be 1.0 times or more and 1.2 times or less the thickness of the base metal plate, the die is moved relative to the punch and the pad along the vertical wall inclination direction, thereby forming the concavely curved vertical wall portion and the convexly curved vertical wall portion to manufacture the intermediate product; A method for manufacturing a press-molded product, characterized in that the convex top plate ridge portion and the convex curved vertical wall portion of the intermediate product are cut to produce a press-molded product including the top plate portion, the concave top plate ridge portion, the concave curved vertical wall portion, the concave flange ridge portion, and the concave flange portion.

8. a length of a straight line portion included in the concavely curved portion of the top plate portion of the intermediate product is 30% or less of a total length of an outline of the concavely curved portion, 8. The method for manufacturing a press-molded product according to claim 7, characterized in that the length of the straight line portion included in the convexly curved portion of the top plate portion of the intermediate product is 30% or less of the total length of the outline of the convexly curved portion.

9. The intermediate product has a plurality of the S-shaped portions, 8. The method for manufacturing a press-formed product according to claim 7, characterized in that the concavely curved vertical wall portion and the convexly curved vertical wall portion corresponding to each S-shaped portion are formed by moving the die relative to the punch and the pad along the vertical wall inclination direction specific to each S-shaped portion.

10. The method for manufacturing a press-formed product according to any one of claims 7 to 9, wherein the base metal plate has a tensile strength of 500 MPa or more.

11. After forming the concavely curved vertical wall portion and the convexly curved vertical wall portion, The intermediate product is removed from the press forming apparatus while maintaining the distance between the pad and the holder in the press direction at the end of forming at not less than 0.95 times the distance between the pad and the holder in the press direction. The method for manufacturing a press-formed product according to any one of claims 7 to 9, characterized in that

12. a top plate portion having an S-shaped portion in which a concavely curved portion and a convexly curved portion are continuously connected in a part of its outline; a concave top ridge portion connected to the concavely curved portion of the top portion; a convex top ridge portion connected to the convexly curved portion of the top portion; a concave curved vertical wall portion connected to the concave top plate ridge line portion on the opposite side to the top plate portion side; a convex curved vertical wall portion connected to the convex top plate ridge line portion on the opposite side to the top plate portion side; a concave flange ridge line portion connected to the concave curved vertical wall portion on the opposite side from the concave top plate ridge line portion side; a concave flange portion connected to the concave flange ridge line portion on the side opposite to the concavely curved vertical wall portion, and wherein an angle formed by the top plate portion and the concavely curved vertical wall portion and an angle formed by the top plate portion and the convexly curved vertical wall portion are each greater than 90 degrees, Punch and a holder disposed on a side of the punch; a pad disposed opposite the punch; a die disposed opposite the holder, The punch is Punched top surface and a punch vertical wall surface including a concavely curved concave surface and a convexly curved convex surface, the angle formed between the punch top surface and the punch vertical wall surface is greater than 90 degrees; The die has a die vertical wall surface having a shape corresponding to the punch vertical wall surface, The die vertical wall surface is parallel to the punch vertical wall surface, A press forming apparatus, characterized in that the die is configured to be movable relatively to the punch and the pad in a direction parallel to a vertical wall surface of the punch.

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