Method for manufacturing a press-formed product and press production line

Abstract

The present invention relates to a manufacturing method of a press-formed product and a press production line. The manufacturing method of a press-formed product (200) includes press-forming a metal sheet into a pre-formed product (100) and press-forming the pre-formed product (100) into a press-formed product (200), the pre-formed product (100) having a pre-formed bottom plate portion (110), a first pre-formed longitudinal wall portion (120a), a second pre-formed longitudinal wall portion (120b), the first pre-formed longitudinal wall portion (120a) being between the second pre-formed longitudinal wall portion (120b), a pre-formed ridge line portion (130) being between the first pre-formed longitudinal wall portion (120a) and the second pre-formed longitudinal wall portion (120b), and a bulging portion (140) being between the pre-formed bottom plate portion (110) and the first pre-formed longitudinal wall portion (120a) and the second pre-formed longitudinal wall portion (120b), the press-formed product (200) having a bottom plate portion (210), a first longitudinal wall portion (220a) adjacent to the bottom plate portion (210), a second longitudinal wall portion (220b) adjacent to the bottom plate portion (210), and a ridge line portion (230) being between the first longitudinal wall portion (220a) and the second longitudinal wall portion (220b).

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a press-formed product and a press production line.

[0002] This application is based on Japanese Patent Application No. 2020-170894 filed on October 9, 2020, the content of which is incorporated herein by reference in its entirety. BACKGROUND

[0003] In order to reduce CO2 emissions based on the CAFE (Corporate Average Fuel Efficiency) regulation and the like, the spread of electric vehicles (Electric Vehicle) is rapidly advancing. At present, high-priced electric vehicles are the mainstream, but in order to achieve the low price of electric vehicles, it is necessary to develop parts that use metal such as steel materials. As one example, forming technologies that use battery cases, front pillar lower parts, door inner parts, and the like made of steel materials and the like are being developed.

[0004] Generally, these parts have a ridge line portion (also referred to as a corner portion), and are manufactured by welding and assembling a plurality of parts. However, in the conventional forming technology, in the case where the curvature radius of the ridge line portion is relatively small, it is not possible to suppress cracks due to a local reduction in the thickness of the plate of the ridge line portion, and it is not possible to form the desired shape.

[0005] As a method of manufacturing a formed product having a ridge line portion, for example, a press forming method is disclosed in Patent Literature 1, in which, in a forming step of a press-formed product having an L shape, a curved portion (ridge line portion) of the L shape is made to protrude outward of a vertical wall portion and to a circular arc shape with a larger curvature radius than a cross section in the direction of extension of the curved portion, and the ridge line portion connected to a top plate portion is formed to a shape that protrudes outward with a larger curvature radius than a cross section in the direction of extension thereof.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: Japanese Patent No. 5708757 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] The present application was completed in view of the above circumstances, and the problem to be solved thereby is to provide a manufacturing method of a press-formed product and a press production line for obtaining a formed product in which cracks and wrinkles are suppressed in a ridge line portion.

[0011] TECHNICAL MEANS FOR SOLVING THE PROBLEMS

[0012] (1) A manufacturing method of a press-formed product according to one aspect of the present application is characterized by,

[0013] The method for manufacturing a press-molded product includes press-forming a metal sheet into a preform, and press-forming the preform into a press-molded product, the preform including a preform bottom plate portion, a first preform longitudinal wall portion, a second preform longitudinal wall portion, a preform ridge line portion between the first preform longitudinal wall portion and the second preform longitudinal wall portion, and a bulge portion between the preform bottom plate portion and the first preform longitudinal wall portion and the second preform longitudinal wall portion, the press-molded product including a bottom plate portion, a first longitudinal wall portion adjacent to the bottom plate portion, a second longitudinal wall portion adjacent to the bottom plate portion, and a ridge line portion between the first longitudinal wall portion and the second longitudinal wall portion, when the preform bottom plate portion and the bottom plate portion, and the preform ridge line portion and the ridge line portion are overlaid with respect to a preform cross section passing through the middle of the first preform longitudinal wall portion and the second preform longitudinal wall portion and a press-molded product cross section passing through the middle of the first longitudinal wall portion and the second longitudinal wall portion, the bulge portion includes a first portion on an inner side of the press-molded product and adjacent to the preform ridge line portion, and a second portion on an outer side of the press-molded product and adjacent to the preform bottom plate portion, the first portion and the second portion being adjacent to each other.

[0014] (2) In the method for manufacturing a press-molded product according to (1), the following can also be true,

[0015] The second portion includes a second A portion closer to the first portion than a point in the second portion farthest from the preform bottom plate portion in a thickness direction of the preform bottom plate portion, and a second B portion closer to the preform bottom plate portion than the point, a radius of curvature of an inner side surface of the first portion and the second A portion of the preform cross section being bent the least being 15 times or more the sheet thickness of the metal sheet.

[0016] (3) In the method for manufacturing a press-molded product according to (1) or (2), the following can also be true,

[0017] When the preform bottom plate portion and the bottom plate portion, and the preform ridge line portion and the ridge line portion are overlaid with respect to the preform cross section and the press-molded product cross section, an absolute value of a difference between a line length of the bulge portion and a line length of a portion of the press-molded product distanced from the bulge portion is 4 times or less the sheet thickness of the metal sheet.

[0018] (4) In the method for manufacturing a press-molded product according to any one of (1) to (3), the following can also be true,

[0019] In the preform cross section and the press-formed product cross section, when the preform bottom plate portion and the bottom plate portion and the preform ridge line portion and the ridge line portion are overlapped respectively, a distance from an intersection point C of an extension line of the bottom plate portion and an extension line of the ridge line portion to the preform bottom plate portion is 60 times or less the sheet thickness of the metal sheet, and a distance from the intersection point C to the preform ridge line portion in a direction perpendicular to the bottom plate portion is 60 times or less the sheet thickness of the metal sheet.

[0020] (5) In the method of manufacturing the press-formed product according to any one of (1) to (4), also,

[0021] The preform has a flange portion adjacent to an end portion of the preform ridge line portion, and in the preform cross section and the press-formed product cross section, when the preform bottom plate portion and the bottom plate portion and the preform ridge line portion and the ridge line portion are overlapped respectively, the flange portion of the press-formed product is positioned on the bottom plate portion side from the flange portion of the preform.

[0022] (6) In the method of manufacturing the press-formed product according to (5), also,

[0023] In the preform cross section and the press-formed product cross section, when the preform bottom plate portion and the bottom plate portion and the preform ridge line portion and the ridge line portion are overlapped respectively, the flange portion of the press-formed product is moved from the flange portion of the preform in a direction perpendicular to the bottom plate portion by a distance of 2 times or more and 30 times or less the sheet thickness of the metal sheet.

[0024] (7) In the method of manufacturing the press-formed product according to (5) or (6), also,

[0025] In the preform cross section, a radius of curvature of an inner side surface of a flange ridge line portion between the flange portion of the preform and the preform ridge line portion is 6 times or more and 30 times or less the sheet thickness of the metal sheet.

[0026] (8) In the method of manufacturing the press-formed product according to any one of (5) to (7), also,

[0027] In the press-formed product cross section, a radius of curvature of an inner side surface of a flange ridge line portion is 10 times or less the sheet thickness of the metal sheet.

[0028] (9) In the method of manufacturing the press-formed product according to any one of (1) to (8), also,

[0029] In a cross section of the ridge line portion parallel to the bottom plate portion, a radius of curvature of an inner side of the curved ridge line portion is 30 times or less of a thickness of the metal plate.

[0030] (10) In the method of manufacturing the press-formed product according to any one of (1) to (9), it can be that

[0031] A cross section of the press-formed product having the first longitudinal wall portion, the second longitudinal wall portion, and the ridge line portion parallel to the bottom plate portion is a closed cross section.

[0032] (11) A press line according to an aspect of the present application is characterized in that

[0033] The first press portion includes a first die, a first punch, and a first support. The second press portion includes a second die and a second punch. A first die bottom surface portion, a first die first side surface portion, a first die second side surface portion, and a first die concave ridge line portion are present on a surface of a die hole of the first die. The first die concave ridge line portion is present between the first die first side surface portion and the first die second side surface portion. A first die bottom surface concave portion, which is concave compared to a central portion of the first die bottom surface portion, is present at a portion of the first die bottom surface portion that is adjacent to an end portion of the first die concave ridge line portion. A second die bottom surface portion, a second die first side surface portion, a second die second side surface portion, and a second die concave ridge line portion are present on a surface of a die hole of the second die. The second die concave ridge line portion is present between the second die first side surface portion and the second die second side surface portion. When the first die bottom surface portion and the second die bottom surface portion, and the first die concave ridge line portion and the second die concave ridge line portion are overlapped with each other with respect to a first die cross section that passes through a middle of the first die first side surface portion and the first die second side surface portion, and a second die cross section that passes through a middle of the second die first side surface portion and the second die second side surface portion, the first die bottom surface concave portion includes a first portion that is present outside the second die and is adjacent to the first die concave ridge line portion, and a second portion that is present inside the second die and is adjacent to the first portion.

[0034] (12) In the press line according to (11), it can be that

[0035] When the bottom surface of the first die and the bottom surface of the second die, and the concave edge of the first die and the concave edge of the second die are respectively overlapped for the first die section and the second die section, the second part includes: a second A part, which is closer to the first part than the point of deepest recess in the second part; and a second B part, which is closer to the center of the bottom surface of the first die than the point mentioned above. The minimum radius of curvature of the first part and the second A part in the first die section is more than 16 times the gap between the first die and the first punch.

[0036] (13) In the stamping production line described in (11) or (12) above, it is also possible to be,

[0037] When the bottom surface of the first die and the bottom surface of the second die, and the concave edge of the first die and the concave edge of the second die are respectively overlapped for the first die section and the second die section, the absolute value of the difference between the line length of the concave part of the bottom surface of the first die and the line length of the bottom surface of the second die that is far away from the concave part of the bottom surface of the first die is less than 4 times the gap between the first die and the first punch.

[0038] (14) In any of the stamping production lines described in (11) to (13) above, it is also possible to be,

[0039] When the bottom surface of the first die and the bottom surface of the second die, and the concave ridge of the first die and the concave ridge of the second die are respectively overlapped for the first die section and the second die section, the distance from the intersection point C of the extension line of the bottom surface of the second die and the extension line of the concave ridge of the second die to the end of the bottom surface of the first die in the second part is less than 60 times the gap between the first die and the first punch, and the distance from the intersection point C to the end of the concave ridge of the first die in the first part in the direction perpendicular to the bottom surface of the first die is less than 60 times the gap.

[0040] (15) In any of the stamping production lines described in (11) to (14) above, it is also possible to be,

[0041] In a cross-section passing through the concave ridge of the first die, which is parallel to the bottom surface of the first die, the radius of curvature of the concave ridge of the first die is less than 31 times the gap between the first die and the first punch.

[0042] The effects of the invention

[0043] According to the method for manufacturing stamped articles and the stamping production line of the present invention, it is possible to obtain stamped articles in which cracks and wrinkles are suppressed at the edge portion. Attached Figure Description

[0044] Figure 1 (a) is a schematic perspective view of the preform, (b) is a schematic perspective view of the molded article, and (c) is a schematic perspective view of the product.

[0045] Figure 2 (a) is a schematic perspective view of the preform, (b) is a schematic perspective view of the molded article, and (c) is a schematic perspective view of the product.

[0046] Figure 3 is a schematic plan view of the preform as viewed from a direction perpendicular to the preform bottom plate portion.

[0047] Figure 4 is a schematic sectional view of the preform as viewed in a plane section through Figure 3 position of the preform.

[0048] Figure 5 is a schematic plan view of the molded article as viewed from a direction perpendicular to the bottom plate portion.

[0049] Figure 6 is a schematic sectional view of the molded article as viewed in a plane section through Figure 5 position of the molded article.

[0050] Figure 7 is a diagram for explaining the radius of curvature of the bulging portion, and is a schematic sectional view of the preform preform ridge portion of the preform.

[0051] Figure 8 is a diagram for explaining the difference in length of the line between the preform and the molded article, and is a schematic sectional view of the preform preform ridge portion of the preform and the ridge portion of the press-molded article.

[0052] Figure 9 is a diagram for explaining the intersection of the imaginary line extending the preform longitudinal wall portion and the preform bottom plate portion, and is a schematic sectional view as viewed by superimposing the preform preform ridge portion (ridge portion) of the preform and the press-molded article.

[0053] Figure 10 is a diagram for explaining the flange portion and the flange ridge portion, and is a schematic sectional view of the preform preform ridge portion of the preform.

[0054] Figure 11 is a schematic side view for explaining the press production line of the second embodiment, (a) is a schematic side view of a continuous automatic press production line, and (b) is a schematic side view of a series-connection continuous press production line.

[0055] Figure 12 is a schematic perspective view for explaining an example of the preform mold of the second embodiment.

[0056] Figure 13 is a schematic plan view of the first punch (first die) as viewed from the bottom surface portion side in a direction perpendicular to the bottom surface portion.

[0057] Figure 14 is a schematic sectional view of the preforming die as viewed in a plane section passing through Figure 13 the D-D' position.

[0058] Figure 15 is a view for explaining a state in which the workpiece is arranged in the preforming die, and is a schematic sectional view of the preforming die and the workpiece as viewed in a plane section passing through Figure 13 the D-D' position.

[0059] Figure 16 is a view for explaining a state in which the workpiece is sandwiched by the first punch (first die) and the first die (second die), and is a schematic sectional view of the preforming die and the workpiece as viewed in a plane section passing through Figure 13 the D-D' position.

[0060] Figure 17 is a view for explaining a state in which the first punch (first die) is relatively moved with respect to the first die (second die), and is a schematic sectional view of the preforming die and the workpiece as viewed in a plane section passing through Figure 13 the D-D' position.

[0061] Figure 18 is a view for explaining a state in which the first punch (first die) reaches a lower dead center, and is a schematic sectional view of the preforming die and the preformed product as viewed in a plane section passing through Figure 13 the D-D' position.

[0062] Figure 19 is a schematic sectional view of the preformed product formed by the preforming die.

[0063] Figure 20 is a schematic perspective view for explaining an example of the official forming die of the second embodiment.

[0064] Figure 21 is a schematic plan view of the second die (fourth die) as viewed from the bottom surface portion side in a direction perpendicular to the bottom surface portion.

[0065] Figure 22 is a view for explaining a state in which the preformed product is arranged in the second die (fourth die), and is a schematic sectional view of the second die (fourth die) and the preformed product as viewed in a plane section passing through Figure 21 the E-E' position.

[0066] Figure 23 is a planar cross-section view of the formal molding die and the preform at the E-E' position. Figure 21

[0067] Figure 24 Figure 23

[0068] Figure 25 Figure 24

[0069] Figure 26

[0070] Figure 27

[0071] Figure 28

[0072] Figure 29 Figure 21

[0073] Figure 30 Figure 21

[0074] Figure 31 Figure 29

[0075] Figure 32 Figure 30

[0076] Figure 33

[0077] Figure 34 ​​​​​​​​​​​​​​​​​is a drawing showing an example of an article that can preferably use the manufacturing method of the press-molded product of the present application.

[0078] Figure 35 is a drawing showing an example of an article that can preferably use the manufacturing method of the press-molded product of the present application.

[0079] Figure 36 is a drawing showing an example of an article that can preferably use the manufacturing method of the press-molded product of the present application.

[0080] Figure 37 is a drawing for explaining the bulging portion of the preform of Example 1, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0081] Figure 38 is a drawing for explaining the bulging portion of the preform of Example 1, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0082] Figure 39 is a drawing for explaining the bulging portion of the preform of Example 1, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0083] Figure 40 is a drawing for explaining the bulging portion of the preform of Example 1, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0084] Figure 41 is a drawing for explaining the bulging portion of the preform of Example 1, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0085] Figure 42 is a drawing for explaining the bulging portion of the preform of Example 1, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0086] Figure 43 is a drawing for explaining the flange portion of the preform of Example 2, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0087] Figure 44 is a drawing for explaining the flange portion of the preform of Example 2, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0088] Figure 45 is a drawing for explaining the flange portion of the preform of Example 2, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0089] Figure 46 is a drawing for explaining the flange portion of the preform of Example 2, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0090] Figure 47 is a drawing for explaining the flange portion of the preform of Example 2, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion.

[0091] Figure 48 is a drawing for explaining the flange portion of the preform of Example 2, (a) is a schematic perspective view of the ridge line portion, and (b) is a schematic cross-sectional view of the ridge line portion. DETAILED DESCRIPTION

[0092] The present inventors have studied a molding method that can mold a shape in which the curvature radius of a ridge line portion that is a cross section transverse to the extending direction of the ridge line portion is small and the molding conditions are strict. Hereinafter, the curvature radius of the ridge line portion of the cross section transverse to the extending direction of the ridge line portion is referred to as the curvature radius of the ridge line portion. According to the study by the present inventors, it was found that, when preforming is performed in a manner in which the longitudinal wall side is stretched as in the technology disclosed in Patent Literature 1, a ridge line portion (corner portion) in which the longitudinal walls are connected to each other is likely to generate a crack at the time of preforming or a wrinkle at the time of official molding. Therefore, the present inventors have studied a manufacturing method of a press-molded product in which a crack or a wrinkle is suppressed at the ridge line portion. The present application was completed in view of the above circumstances.

[0093] Hereinafter, embodiments of the present application will be described by way of example, but the present application is of course not limited to the examples described below. In the following description, specific numerical values and materials are sometimes exemplified, but other numerical values and materials can also be applied as long as the effects of the present application can be obtained. Furthermore, each of the constituent elements of the following embodiments can be combined with each other.

[0094] [1st Embodiment]

[0095] The manufacturing method of the press-formed product of the present embodiment includes a step of press-forming a metal sheet into a preform, the preform including a preform bottom plate portion, a first preform longitudinal wall portion, a second preform longitudinal wall portion, a preform ridge line portion between the first preform longitudinal wall portion and the second preform longitudinal wall portion, and a bulge portion between the preform bottom plate portion and the first preform longitudinal wall portion and the second preform longitudinal wall portion. The manufacturing method of the press-formed product of the present embodiment also includes a step of press-forming the preform into a press-formed product, the press-formed product including a bottom plate portion, a first longitudinal wall portion adjacent to the bottom plate portion, a second longitudinal wall portion adjacent to the bottom plate portion, and a ridge line portion between the first longitudinal wall portion and the second longitudinal wall portion. The manufacturing method of the press-formed product of the present embodiment is characterized in that, when the preform bottom plate portion and the bottom plate portion, and the preform ridge line portion and the ridge line portion are overlapped with each other with respect to a preform cross section passing through the middle of the first preform longitudinal wall portion and the second preform longitudinal wall portion and a press-formed product cross section passing through the middle of the first longitudinal wall portion and the second longitudinal wall portion, the bulge portion includes a first portion on an inner side of the press-formed product and adjacent to the preform ridge line portion, and a second portion on an outer side of the press-formed product and adjacent to the preform bottom plate portion, the first portion being adjacent to the second portion.

[0096] In the manufacturing method of the press-formed product including the above configuration, the bulge portion is formed in the end portion region of the preform bottom plate portion in the preforming step, and press-forming is performed in the final forming step in such a manner that the bulge portion becomes part of the bottom plate portion and the longitudinal wall portion of the formed product, whereby a formed product in which cracks and wrinkles are suppressed in the ridge line portion can be obtained.

[0097] In Figure 1 (a) of the drawings, a schematic perspective view of a preform is shown, in Figure 1 (b) of the drawings, a schematic perspective view of a press-formed product is shown, and in Figure 1 (c) of the drawings, a schematic perspective view of a product is shown. In a preforming step (S1), a metal sheet (not shown) is press-formed to form a preform 100 as shown in (a) of the drawings. In a final forming step (S2), the preform 100 is further press-formed to form a press-formed product 200 as shown in (b) of the drawings. The press-formed product 200 can be further processed in a further processing step (S3) to become a product 300 as shown in (c) of the drawings. Figure 1 Figure 1 Figure 1 ​​The article 300 shown in (c) can be manufactured by performing the press forming on the preform 100 shown in (b). Alternatively, the press-formed article 200 can be used as the final article. The article 300 can be preferably used as a battery case for a vehicle, for example. In addition, as a battery case for a vehicle, a high capacity is required and sealing performance for coping with leakage of battery liquid is ensured. In order to meet this requirement, it is more advantageous to mold the article 300 into a square tube shape by integral molding than to join a plurality of parts to form a square tube shape.

[0098] Figure 2 is an enlarged perspective view of the corner portion or the vicinity of the corner portion of (a) to (c) of the preform 100 or the press-formed article 200. As shown in (a) of Figure 1 (a), the preform 100 has a preform bottom panel portion 110, a preform corner portion 130 between preform longitudinal wall portions 120 (a first preform longitudinal wall portion 120a and a second preform longitudinal wall portion 120b), and a bulging portion 140 between the preform bottom panel portion 110 and the preform longitudinal wall portions 120. In the example of (a), the preform 100 also has a flange portion 150. In addition, as shown in (b), the press-formed article 200 has a bottom panel portion 210 and a corner portion 230 between longitudinal wall portions 220 (a first longitudinal wall portion 220a and a second longitudinal wall portion 220b) adjacent to the bottom panel portion 210. Furthermore, as shown in (c), the article 300 can have a flange portion 350 that is trimmed. Figure 2 Figure 2 Figure 2 Figure 2

[0099] (Prefabrication process)

[0100] In the pre-fabrication process (S1), a preform 100 is molded by press forming a metal sheet. The preform 100 has a preform bottom panel portion 110 corresponding to the bottom panel portion 210, a plurality of preform longitudinal wall portions 120 (a first preform longitudinal wall portion 120a and a second preform longitudinal wall portion 120b) corresponding to the longitudinal wall portions 220 and rising from the preform bottom panel portion 110, and a preform corner portion 130 corresponding to the corner portion 230 and connecting the preform longitudinal wall portions 120 to each other. The metal sheet can be a steel sheet, an aluminum alloy sheet, a titanium alloy sheet, or a composite material thereof. From the aspect of material elongation, a steel sheet having a tensile strength of 270 to 440 MPa is more preferably used. In addition, the metal sheet can be processed by plating treatment or the like for the purpose of rust prevention and corrosion prevention.

[0101] ​​​​Furthermore, in the preforming step (S1), a bulging portion 140 is formed in an end portion region 111 of the preformed longitudinal wall portion 120 in the preformed bottom plate portion 110, which, as viewed in a cross section orthogonal to the plate surface of the preformed bottom plate portion 110 and passing through the preformed ridge line portion 130, is entirely located on the preformed bottom plate portion 110 side than the preformed longitudinal wall portion 120 and bulges toward the side opposite to the side on which the preformed longitudinal wall portion 120 stands. The bulging portion 140 is connected to the preformed bottom plate portion 110, the preformed longitudinal wall portion 120, and the preformed ridge line portion 130. The end portion region 111 is a partial region of the preformed bottom plate portion 110 and is a region near the edge portion of the preformed bottom plate portion 110 to which the preformed longitudinal wall portion 120 and the preformed ridge line portion 130 are connected. The preformed ridge line portion 130 is a portion of the preformed longitudinal wall portion 120, and in the present embodiment, the preformed longitudinal wall portion 120 can be replaced with the preformed ridge line portion 130.

[0102] Figure 3 A schematic plan view of the preform 100 as viewed from a direction orthogonal to the preformed bottom plate portion 110 is shown. In the present embodiment, the preform 100 has a preformed bottom plate portion 110 having a substantially rectangular shape. Figure 3 Figure 4 A schematic cross-sectional view of the preform 100 as viewed in a plane orthogonal to the plate surface of the preformed bottom plate portion 110 at the A-A' position of Figure 3 Figure 4 is an example of a schematic cross-sectional view of the preform 100 as viewed in a plane orthogonal to the plate surface of the preformed bottom plate portion 110 and passing through the preformed ridge line portion 130. By Figure 3 The plane at the A-A' position of

[0103] The bulging portion 140 is connected to the preformed bottom plate portion 110, the preformed longitudinal wall portion 120, and the preformed ridge line portion 130. The entire bulging portion 140 is located on the preformed bottom plate portion 110 side than the preformed longitudinal wall portion 120 or the preformed ridge line portion 130. Specifically, the entire range of the bulging portion 140 is located on the preformed bottom plate portion 110 side than an imaginary line obtained by extending the preformed longitudinal wall portion 120 or the preformed ridge line portion 130, as viewed in the above cross section. Furthermore, a part or the entire bulging portion 140 bulges toward the side opposite to the side on which the preformed longitudinal wall portion 120 stands with respect to the plate surface of the preformed bottom plate portion 110.

[0104] ​​The bulging portion 140 is preferably smoothly connected to the preform bottom portion 110, the preform longitudinal wall portion 120, and the preform ridge line portion 130, and is preferably formed in a curved shape in the aforementioned cross-sectional view. Further, the bulging portion 140 is more preferably extended to the side on which the preform longitudinal wall portion 120 is erected with respect to the surface of the preform bottom portion 110. In the case of viewing from the direction perpendicular to the surface of the preform bottom portion 110, the bulging portion 140 can be provided in the range including the entire preform ridge line portion 130, or can be provided in a portion including the central portion of the preform ridge line portion 130. In addition, as shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100, the bulging portion 140 can also be provided in the entire range of the end portion region 111 of the preform bottom portion 110, but this is not essential. Figure 2 , Figure 3 As shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100, the bulging portion 140 can also be provided in the entire range of the end portion region 111 of the preform bottom portion 110, but this is not essential.

[0105] The preform product 100 obtained in the preforming step (S1) can also be used as an intermediate product of a press-molded product. That is, the intermediate product of the present embodiment is an intermediate product for manufacturing a press-molded product having a bottom portion, a plurality of longitudinal wall portions connected to the bottom portion and erected from the bottom portion, and a ridge line portion connecting the longitudinal wall portions to each other, and is characterized by having a preform bottom portion corresponding to the bottom portion, a plurality of preform longitudinal wall portions corresponding to the longitudinal wall portions and erected from the preform bottom portion, and a preform ridge line portion corresponding to the ridge line portion and connecting the preform longitudinal wall portions to each other, and a bulging portion provided in an end portion region of the preform bottom portion in which the preform longitudinal wall portions are erected, and in which, in a cross section orthogonal to the surface of the preform bottom portion and passing through the preform ridge line portion, the entire bulging portion is located on the preform bottom portion side with respect to the preform longitudinal wall portions and connected to the preform longitudinal wall portions, and bulges toward the side opposite to the side on which the preform longitudinal wall portions are erected and connected to the preform bottom portion.

[0106] In the intermediate product formed by the above configuration, the bulging portion is provided in the end portion region of the preform bottom portion. By press-molding the bulging portion of the intermediate product as part of the bottom portion and the longitudinal wall portion of the molded product, a molded product in which cracks and wrinkles are suppressed in the ridge line portion can be obtained.

[0107] (Formal molding step)

[0108] In the formal molding step (S2), the preform product 100 is press-molded into a press-molded product 200 having a bottom portion 210, a longitudinal wall portion 220 (a first longitudinal wall portion 220a and a second longitudinal wall portion 220b) adjacent to the bottom portion 210, and a ridge line portion 230 between the longitudinal wall portions 220. Figure 5 FIG. 2 shows a schematic plan view of the press-molded product 200 when viewed from the direction perpendicular to the surface of the bottom portion 210. Further, Figure 6 FIG. 3 shows a schematic cross-sectional view of the press-molded product 200 when viewed in the direction of the arrow III-III in FIG. 2. Figure 5a cross-sectional view of the press-formed product 200 when viewed in a plane orthogonal to the plate surface of the bottom plate portion 210 at the B-B' position. Figure 6 A cross-sectional view of the press-formed product 200 when viewed in a plane orthogonal to the plate surface of the bottom plate portion 210 at the B-B' position. Figure 5 The plane at the B-B' position can also be a press-formed product cross section through the middle of the first longitudinal wall portion 220a and the second longitudinal wall portion 220b. Specifically, it can be a plane orthogonal to the plate surface of the bottom plate portion 210 of the press-formed product 200 and equal to the angle between the plate surfaces of the respective longitudinal wall portions 220 connected via the ridge line portion 230. In the final forming step (S2), the bulging portion 140 shown in Figure 4 The bulging portion 140 shown in (a) is press-formed as part of the bottom plate portion 210, the longitudinal wall portion 220, and the ridge line portion 230 to become the shape shown in (b). Figure 6 The bottom plate portion 210 and the longitudinal wall portion 220 (or the ridge line portion 230) shown in (b) are connected by the longitudinal ridge line portion 221. The ridge line portion 230 is part of the longitudinal wall portion 220, and in this embodiment, the longitudinal wall portion 220 can be replaced by the ridge line portion 230.

[0109] In the press-formed product cross section through the middle of the first longitudinal wall portion 220a and the second longitudinal wall portion 220b, the radius of curvature Rw of the inner surface of the longitudinal ridge line portion 221 is preferably 10 times or less the thickness of the metal plate. The face on the inside of the longitudinal ridge line portion 221 is the inner surface of the longitudinal ridge line portion 221. The longitudinal ridge line portion 221 is connected to the bottom plate portion 210, the longitudinal wall portion 220, and the ridge line portion 230.

[0110] After the final forming step (S2), a machining step (S3) can also be performed. In the machining step (S3), cutting, bending, trimming of the flange portion, or the like can be performed. In the example of (c) of the press-formed product 200 shown in Figure 1 In the example of (c) of the press-formed product 200 shown in

[0111] Furthermore, when in the final forming step, the pre-formed bottom plate portion 110 and the bottom plate portion 210, and the pre-formed ridge line portion 130 and the ridge line portion 230 are overlapped respectively with respect to the pre-formed product cross section through the middle of the pre-formed longitudinal wall portion 120 (the first pre-formed longitudinal wall portion 120a and the second pre-formed longitudinal wall portion 120b) and the press-formed product cross section through the middle of the longitudinal wall portion 220 (the first longitudinal wall portion 220a and the second longitudinal wall portion 220b), the bulging portion 140 has a first portion 141 inside the press-formed product 200 and adjacent to the pre-formed ridge line portion 130, and a second portion 142 outside the press-formed product 200 and adjacent to the pre-formed bottom plate portion 110, and the first portion 141 and the second portion 142 are adjacent.

[0112] The inner side of the press-formed product 200 refers to the curved inner side of the press-formed product 200. Similarly, the outer side of the press-formed product 200 refers to the curved outer side of the press-formed product 200. Further, the pre-formed ridge portion 130 and the ridge portion 230 overlap each other as described herein refers to the relationship when the cross-sectional views are overlapped. The curvature of the press-formed product 200 refers to the curvature between the floor portion 210 and the vertical wall portion 220. Figure 8 The cross-sectional view will be described in detail later.

[0113] In the manufacturing method of the press-formed product of the present embodiment, the second portion 142 has a second A portion on the first portion side from a point in the second portion 142 that is farthest from the pre-formed floor portion 110 in the thickness direction of the pre-formed floor portion 110, and a second B portion on the pre-formed floor portion 110 side from the point, and the radius of curvature of the inner side surface of the first portion 141 of the pre-formed product cross section and the second A portion where the curvature is smallest can also be 15 times or more the sheet thickness of the metal sheet.

[0114] Figure 7 The cross-sectional view of the pre-formed product through the middle of the first pre-formed vertical wall portion 120a and the second pre-formed vertical wall portion 120b is shown. The middle herein refers to a plane that is orthogonal to the plane of the pre-formed floor portion 110 of the pre-formed product 100 and that has an angle equal to the angle between the planes of the respective pre-formed vertical wall portions 120 connected via the pre-formed ridge portion 130. As shown in Figure 7 The point 140a of the bulge portion 140 connected to the pre-formed vertical wall portion 120 (or the pre-formed ridge portion 130) refers to the boundary between the pre-formed vertical wall portion 120 (or the pre-formed ridge portion 130) having a substantially linear cross section and the bulge portion 140 having a curved cross section. In Figure 7 In the cross-sectional view, the point 140a is a point on the inner surface of the pre-formed product 100. As shown in Figure 7 The point 140b of the bulge portion 140 farthest from the pre-formed floor portion 110 refers to a point on the inner surface of the bulge portion 140 in the direction perpendicular to the plane of the pre-formed floor portion 110 at which the distance (Δp) from the inner surface of the pre-formed floor portion 110 becomes the largest. Here, the inner surfaces of the pre-formed floor portion 110 and the bulge portion 140 refer to the surfaces on the side where the pre-formed vertical wall portion 120 is located with respect to the pre-formed floor portion 110. Figure 7

[0115] Further, Figure 8 The cross-sectional view in which the cross section of the pre-formed product 100 (solid line) and the cross section of the press-formed product 200 (double-dot chain line) are overlapped is shown. As shown in Figure 8 The point 140c of the bulge portion 140 connected to the pre-formed floor portion 110 refers to the boundary between the pre-formed floor portion 110 having a substantially linear cross section and the bulge portion 140 having a curved cross section.​Figure 8 In the cross-sectional view, the point 140c is a point on the inner surface of the preform 100. Here, the inner surface of the preform 100 refers to the inner surface of the bulging portion 140 and the preform bottom portion 110.

[0116] The shape of the preform 100 is a shape in which strain concentration is moderated in the press forming. That is, when the second portion 142 is flattened, metal is pressed from the second portion 142 toward the first portion 141, and thus the strain concentration of the first portion 141 can be moderated. Since the metal is directly pressed from the second portion 142 toward the first portion 141, the first portion 141 is adjacent to the second portion 142. If the first portion 141 is distanced from the second portion 142, the portion therebetween will absorb the metal extruded from the second portion 142. The second portion 142 protrudes toward the outside of the press-formed product 200. When the second portion 142 protrudes toward the inside, a curved portion will be present between the first portion 141 and the second portion 142. When the curved portion is present, it is possible to suppress the flow of metal from the second portion 142 toward the first portion 141. By setting the radius of curvature of the inner surface of the first portion 141 and the second portion 2A in which the curvature is smallest in the above-described cross section to be 15 times or more the sheet thickness of the metal sheet, it is possible to more stably suppress cracking. Further, it is more preferable to set the radius of curvature to be 18 times or more the sheet thickness of the metal sheet. Here, the radius of curvature is set to be the radius of curvature of the inner surface of the preform bottom portion 110.

[0117] In the manufacturing method of the press-formed product of the present embodiment, when the preform bottom portion 110 and the bottom portion 210, and the preform ridge portion 130 and the ridge portion 230 overlap each other in the cross section of the preform and the cross section of the press-formed product, respectively, the absolute value of the difference between the line length of the bulging portion 140 and the line length of the portion of the press-formed product 200 distanced from the bulging portion 140 can also be 4 times or less the sheet thickness of the metal sheet.

[0118] The absolute value of the difference between the line length of the bulging portion 140 and the line length of the portion of the press-formed product 200 distanced from the bulging portion 140 in the cross section of the preform 100 and the press-formed product 200 is set to ΔL. Figure 8 In the example of the preform 100 and the press-formed product 200,

[0119] In the example of the preform 100 and the press-formed product 200, Figure 8 In the example of the preform 100 and the press-formed product 200, Figure 3 The cross section passing through the A-A' position of the preform 100 and the press-formed product 200 is the same plane as the cross section passing through the B-B' position of the preform 100 and the press-formed product 200. That is, in the preform 100 and the press-formed product 200, Figure 5 In the example of the preform 100 and the press-formed product 200, Figure 8 In the example of the preform 100 and the press-formed product 200,

[0120] When the line length of the preform 100 is too large compared to the press-formed product 200, the metal flow from the second portion 142 cannot be completely absorbed in the first portion 141, and thus a wrinkle is generated in the press-formed product 200. Conversely, when the line length of the preform 100 is too small compared to the press-formed product 200, the metal flow to the first portion 141 is insufficient, and thus a crack is generated in the press-formed product. By the ΔL being 4 times or less the sheet thickness of the metal sheet, it has the effect of being able to more stably suppress the ridge line portion 230 from generating a crack or a wrinkle in the official forming process. Further, it is more preferable that the ΔL be 2 times or less the sheet thickness of the metal sheet.

[0121] In the manufacturing method of the press-formed product of the present embodiment, it can also be that, when the preform floor portion 110 and the floor portion 210, and the preform ridge line portion 130 and the ridge line portion 230 are overlapped respectively with respect to the preform cross section and the press-formed product cross section, the distance from the intersection point C of the extension line of the floor portion 210 and the extension line of the ridge line portion 230 to the preform floor portion 110 is 60 times or less the sheet thickness of the metal sheet, and the distance from the intersection point C to the preform ridge line portion 130 in the direction perpendicular to the floor portion 210 is 60 times or less the sheet thickness of the metal sheet.

[0122] Figure 9 With Figure 8 Likewise, a cross-sectional view is shown in which the cross section of the preform 100 (solid line) and the cross section of the press-formed product 200 (double-dot chain line) are overlapped. The intersection point C is the intersection point of the imaginary lines in which the floor portion 210 (preform floor portion 110) and the ridge line portion 230 (preform ridge line portion 130) in the above cross section are extended. By setting the distance from the intersection point C to the preform floor portion 110 to be the distance el, and the distance in the direction perpendicular to the preform floor portion 110 from the intersection point C to be the distance e2, and setting the distance el and the distance e2 to be 60 times or less the sheet thickness of the metal sheet, it has the effect of being able to effectively flow the bulge portion 140 toward the longitudinal wall ridge line portion 221 in the official forming process. Further, it is more preferable that the distance el and the distance e2 be 45 times or less the sheet thickness of the metal sheet. The distance el and the distance e2 can also be replaced by the height el of the bulge portion 140 and the length e2 of the bulge portion 140, respectively. In addition, the lower limit of the distance el and the distance e2 is 5 times or more the sheet thickness of the metal sheet.

[0123] In the manufacturing method of the press-formed product of the present embodiment, it can also be that the preform 100 has a flange portion 150 that is adjacent to the end portion of the preform ridge line portion 130, and when the preform floor portion 110 and the floor portion 210, and the preform ridge line portion 130 and the ridge line portion 230 are overlapped respectively with respect to the preform cross section and the press-formed product cross section, the flange portion 150 of the press-formed product 200 is positioned on the floor portion 210 side than the flange portion 150 of the preform 100.

[0124] The flange portion 150 can also be formed in the preforming step (S1). Figure 10 An example of a schematic sectional view of the preform 100 as viewed in a plane orthogonal to the plate surface of the preformed bottom plate portion 110 and passing through the preformed ridge line portion 130 is shown. As shown in Figure 10 The flange portion 150 is connected to the preformed longitudinal wall portion 120 via the flange ridge line portion 151 at the front end portion 122 side of the preformed longitudinal wall portion 120 (preformed ridge line portion 130). Further, although not shown, at the base end portion 121 side of the preformed longitudinal wall portion 120, the preformed longitudinal wall portion 120 is connected to the preformed bottom plate portion 110. In addition, Figure 10 The cross section passing through the preformed ridge line portion 130 is illustrated, but the flange portion 150 and the flange ridge line portion 151 can also be configured the same in a cross section orthogonal to the plate surface of the preformed bottom plate portion 110 and not passing through the preformed ridge line portion 130.

[0125] In the final forming step (S2), the flange portion 150 is relatively moved with respect to the bottom plate portion 210 so that the flange portion 150 approaches the bottom plate portion 210 in a direction perpendicular to the plate surface of the bottom plate portion 210, whereby the flange portion 250 of the press-formed product 200 is disposed at a position closer to the bottom plate portion 210 than the flange portion 150 of the preform 100. Thus, in the ridge line portion 230 of the press-formed product 200, cracks and wrinkles in the flange portion 250 after deformation of the flange portion 150 can be suppressed.

[0126] Further, in the method of manufacturing the press-formed product of the present embodiment, the flange portion 250 of the press-formed product 200 can be moved from the flange portion 150 of the preform 100 in the direction perpendicular to the bottom plate portion 210 by a distance of 2 times or more and 30 times or less of the plate thickness of the metal sheet when the preform cross section and the press-formed product cross section are projected so that the preformed bottom plate portion 110 and the bottom plate portion 210, and the preformed ridge line portion 130 and the ridge line portion 230 overlap, respectively. By being configured in this way, it is possible to have the effect that the material allowance of the flange portion 150 generated in the preforming step is effectively extended in the circumferential direction of the preformed ridge line portion 130. The distance moved is more preferably 5 times or more and 25 times or less of the plate thickness of the metal sheet in the direction perpendicular to the plate surface of the bottom plate portion 210.

[0127] Further, in the manufacturing method of the press-formed product of the present embodiment, the radius of curvature of the inner side surface of the curved flange ridge portion 151 between the flange portion 150 and the preform ridge portion 130 in the cross section of the preform 100 can be 6 times or more and 30 times or less of the thickness of the metal sheet. Further, in the case where the radius of curvature varies in the flange ridge portion 151, it is only necessary that the radius of curvature be 6 times or more and 30 times or less of the thickness of the metal sheet in the entire range. The inner side surface of the curved flange ridge portion 151 refers to the surface on the inner side of the flange ridge portion 151 and refers to the surface on the side where the flange portion 150 is located with respect to the preform longitudinal wall portion 120. By being configured in this way, it is possible to prevent the material of the flange portion 150 from breaking and to effectively extend the material allowance of the flange portion 150 in the circumferential direction of the preform ridge portion 130. The radius of curvature is more preferably 10 times or more and 25 times or less of the thickness of the metal sheet.

[0128] In the manufacturing method of the press-formed product of the present embodiment, the radius of curvature of the inner side surface of the curved flange ridge portion 151 between the flange portion 150 and the preform ridge portion 130 in the cross section of the preform 100 can be 6 times or more and 30 times or less of the thickness of the metal sheet. Further, in the case where the radius of curvature varies in the flange ridge portion 151, it is only necessary that the radius of curvature be 6 times or more and 30 times or less of the thickness of the metal sheet in the entire range. The inner side surface of the curved flange ridge portion 151 refers to the surface on the inner side of the flange ridge portion 151 and refers to the surface on the side where the flange portion 150 is located with respect to the preform longitudinal wall portion 120. By being configured in this way, it is possible to prevent the material of the flange portion 150 from breaking and to effectively extend the material allowance of the flange portion 150 in the circumferential direction of the preform ridge portion 130. The radius of curvature is more preferably 10 times or more and 25 times or less of the thickness of the metal sheet.

[0129] In the manufacturing method of the press-formed product of the present embodiment, the radius of curvature of the inner side surface of the curved flange ridge portion 151 between the flange portion 150 and the preform ridge portion 130 in the cross section of the preform 100 can be 6 times or more and 30 times or less of the thickness of the metal sheet. Further, in the case where the radius of curvature varies in the flange ridge portion 151, it is only necessary that the radius of curvature be 6 times or more and 30 times or less of the thickness of the metal sheet in the entire range. The inner side surface of the curved flange ridge portion 151 refers to the surface on the inner side of the flange ridge portion 151 and refers to the surface on the side where the flange portion 150 is located with respect to the preform longitudinal wall portion 120. By being configured in this way, it is possible to prevent the material of the flange portion 150 from breaking and to effectively extend the material allowance of the flange portion 150 in the circumferential direction of the preform ridge portion 130. The radius of curvature is more preferably 10 times or more and 25 times or less of the thickness of the metal sheet.

[0130] In the manufacturing method of the press-formed product of the present embodiment, the cross section of the press-formed product 200 having the first longitudinal wall portion 220a, the second longitudinal wall portion 220b, and the ridge portion 230 and being parallel to the bottom plate portion 210 can also be a closed cross section.

[0131] Further, the manufacturing method of a press-formed product of the present embodiment is a manufacturing method of a press-formed product provided with a bottom plate portion, a plurality of vertical wall portions connected to the bottom plate portion and standing from the bottom plate portion, and a ridge line portion connecting the vertical wall portions to each other. In the manufacturing method of a press-formed product, it is characterized by having: a pre-forming step of performing press forming on a metal sheet to form a pre-formed product provided with a pre-formed bottom plate portion corresponding to the bottom plate portion, a plurality of pre-formed vertical wall portions corresponding to the vertical wall portions and standing from the pre-formed bottom plate portion, and a pre-formed ridge line portion corresponding to the ridge line portion and connecting the pre-formed vertical wall portions to each other; and a final forming step of further performing press forming on the pre-formed product to form the bottom plate portion, the vertical wall portions, and the ridge line portion. In the pre-forming step, a bulging portion is formed in an end portion region of the pre-formed vertical wall portion standing from the pre-formed bottom plate portion, in which, in a cross-sectional view orthogonal to a plate surface of the pre-formed bottom plate portion and passing through the pre-formed ridge line portion, the entire portion is located on a side of the pre-formed bottom plate portion than the pre-formed vertical wall portion and connected to the pre-formed vertical wall portion, and bulges on a side opposite to a side on which the pre-formed vertical wall portion stands and is connected to the pre-formed bottom plate portion. In the final forming step, the bulging portion is formed as a part of the bottom plate portion and the vertical wall portions by press forming.

[0132] [2nd Embodiment]

[0133] The press production line of the present embodiment is characterized by having: a first press portion provided with a first punch (a first die), a first die (a second die), and a first support (a third die); and a second press portion provided with a second punch (a fourth die) and a second die (a fifth die). On a surface of a punch hole of the first punch, there are a first punch bottom surface portion, a first punch first side surface portion, a first punch second side surface portion, and a first punch concave ridge line portion. The first punch concave ridge line portion is between the first punch first side surface portion and the first punch second side surface portion. At a portion of the first punch bottom surface portion adjacent to an end portion of the first punch concave ridge line portion, there is a first punch bottom surface concave portion that is recessed more than a central portion of the first punch bottom surface portion. On a surface of a punch hole of the second punch, there are a second punch bottom surface portion, a second punch first side surface portion, a second punch second side surface portion, and a second punch concave ridge line portion. The second punch concave ridge line portion is between the second punch first side surface portion and the second punch second side surface portion. When the first punch bottom surface portion and the second punch bottom surface portion, and the first punch concave ridge line portion and the second punch concave ridge line portion are overlapped with each other with respect to a first punch cross section passing through a middle of the first punch first side surface portion and the first punch second side surface portion, and a second punch cross section passing through a middle of the second punch first side surface portion and the second punch second side surface portion, the first punch bottom surface concave portion has a first portion on an outer side of the second punch and adjacent to the first punch concave ridge line portion, and a second portion on an inner side of the second punch and adjacent to the first portion.

[0134] Figure 11 This is a side view of the stamping production line according to this embodiment. (a) shows a continuous automatic stamping production line, in which a first stamping section 3000 and a second stamping section 4000 are provided in a single stamping press 5000. The workpiece 1 is placed on a conveyor belt 5100 and conveyed in the direction (X direction) from the first stamping section 3000 toward the second stamping section 4000. The workpiece 1 processed by the first stamping section 3000 is set as a preform 100. The preform 100 is conveyed to the second stamping section 4000 via an automatic conveying mechanism 6000. Furthermore, the workpiece 1 processed by the second stamping section 4000 is set as a stamped product 200. In addition, the stamping process in the second stamping section 4000 can be either deep drawing or bending. (b) represents a series continuous stamping production line, in which a stamping section (first stamping section 3000, second stamping section 4000) is provided for each stamping press 5000. The workpiece 1 is placed on the conveyor belt 5100 and moves in the direction (X direction) from the first stamping section 3000 toward the second stamping section 4000. The workpiece 1 processed by the first stamping section 3000 is set as a preform 100. The preform 100 is conveyed to the second stamping section 4000 via the conveyor 6100. Furthermore, the workpiece 1 processed by the second stamping section 4000 is set as a stamped product 200. In addition, the stamping in the second stamping section 4000 can be either deep drawing or bending.

[0135] Figure 12 This illustrates an example of the first stamping section 3000 (preforming mold 10) of this embodiment. The first stamping section 3000 includes a first punch 500, a first die 600 that clamps the workpiece 1 between itself and the first punch 500, and a first support 700 that clamps the workpiece 1 between itself and the first die 600 in a manner that allows the workpiece 1 to move along its in-plane direction. For example... Figure 12As shown, the first punch 500, the first die 600, and the first holder 700 are arranged along the pressing direction P. The first punch 500, the first die 600, and the first holder 700 are relatively movable in the pressing direction P, respectively. In addition, the first punch 500, the first die 600, and the first holder 700 can also be relatively movable in a direction other than the pressing direction P. In addition, the first punch 500, the first die 600, and the first holder 700 can be integrated, respectively, or can be capable of being divided, respectively. For example, the first punch 500 can also be divided into four divided dies each including the first punch ridge line portion 530 described later in a direction perpendicular to the pressing direction. In addition, the number of divisions of the first punch 500 is not limited to four. For example, the first punch 500 can also be divided into an end die including the first punch ridge line portion 530 and a central die including the central region of the first punch bottom surface portion 510. In addition, a drive portion or a cam mechanism configured to relatively move the divided dies can be provided. The divided dies including the first punch ridge line portion 530 can be relatively movable so as to approach the first punch ridge line portion 530 toward the first die recess line portion 630 of the first die 600 as the first punch 500 approaches the first die 600 in the process of press forming. By being configured by dividing the die, the force required for forming the preform ridge line portion can be alleviated. The second punch 900 described later can also be configured to be divided in the same manner as the first punch 500.

[0136] (First punch)

[0137] Figure 13 A schematic plan view showing a case where the first punch 500 is viewed from the first punch bottom surface portion 510 side in a direction perpendicular to the first punch bottom surface portion 510. In the example of FIG. 6, the first punch bottom surface portion 510 is provided on the surface of the die hole of the first punch 500 in a substantially rectangular shape. Figure 13 Figure 14 A schematic plan view showing a case where the first punch 500 is viewed from the first punch bottom surface portion 510 side in a direction perpendicular to the first punch bottom surface portion 510. In the example of FIG. 6, the first punch bottom surface portion 510 is provided on the surface of the die hole of the first punch 500 in a substantially rectangular shape. Figure 13 A schematic sectional view of the first punch 500, the first die 600, and the first holder 700, showing a case where the D-D' position of FIG. 6 is viewed in a plane orthogonal to the plate surface of the first punch bottom surface portion 510. By the plane of the D-D' position of FIG. 6, the first punch 500, the first die 600, and the first holder 700 can be viewed in a plane orthogonal to the plate surface of the first punch bottom surface portion 510. Figure 13 The plane of the D-D' position of FIG. 6 can also be a plane orthogonal to the plate surface of the first punch bottom surface portion 510 and equal to the angle between the plate surface of each first punch side surface portion 520 connected via the first punch ridge line portion 530.

[0138] ​The first punch 500 has a first punch bottom surface portion 510 on the surface of the die hole, a plurality of first punch side surface portions (a first punch first side surface portion and a first punch second side surface portion) 520 connected to the first punch bottom surface portion 510 and rising from the first punch bottom surface portion 510, and a first punch ridge line portion 530 connecting the first punch side surface portions 520 to each other. That is, the first punch ridge line portion 530 is between the first punch first side surface portion and the first punch second side surface portion. In an end portion region 511 of the first punch bottom surface portion 510 in which the first punch side surface portions 520 and the first punch ridge line portion 530 rise, a first punch bottom surface ridge portion 540 is provided, which, in a cross section orthogonal to the pressing surface of the first punch bottom surface portion 510 and passing through the first punch ridge line portion 530, is connected to the first punch side surface portion 520 at a position on the first punch bottom surface portion 510 side than the first punch side surface portion 520 and is connected to the first punch bottom surface portion 510 by bulging toward the side opposite to the side on which the first punch side surface portion 520 rises. That is, at the portion of the first punch bottom surface portion 510 adjacent to the end portion of the first punch ridge line portion 530, there is a portion of the first punch bottom surface ridge portion 540 that protrudes more than the central portion of the first punch bottom surface portion 510. The end portion region 511 is a portion of the first punch bottom surface portion 510 and is a region near the edge portion at which the first punch side surface portions 520 and the first punch ridge line portion 530 are connected. The first punch ridge line portion 530 is a portion of the first punch side surface portion 520, and in the present embodiment, the first punch side surface portion 520 can be replaced by the first punch ridge line portion 530. Furthermore, the die hole can be not only a hole having a closed cross section in which the first punch side surface portion 520 becomes a closed cross section in a cross section of the first punch 500 parallel to the first punch bottom surface portion 510, but also a hole having an open cross section in which the first punch side surface portion 520 becomes an open cross section in a cross section of the first punch 500 parallel to the first punch bottom surface portion 510.

[0139] The first punch bottom surface ridge portion 540 is connected to the first punch bottom surface portion 510, the first punch side surface portion 520, and the first punch ridge line portion 530. The entire first punch bottom surface ridge portion 540 is positioned on the first punch bottom surface portion 510 side than the first punch side surface portion 520 or the first punch ridge line portion 530. Specifically, in the cross section described above, the entire first punch bottom surface ridge portion 540 is positioned on the first punch bottom surface portion 510 side than an imaginary line extending the first punch side surface portion 520 or the first punch ridge line portion 530. The first punch bottom surface ridge portion 540 bulges toward the side opposite to the side on which the first punch side surface portion 520 rises with respect to the plate surface of the first punch bottom surface portion 510. The surface of the first punch bottom surface ridge portion 540 is preferably smoothly connected to the preform bottom plate portion 110, the first punch side surface portion 520, and the first punch ridge line portion 530. In the cross section described above, the first punch bottom surface ridge portion 540 is preferably composed of a curved line.

[0140] (1st die)

[0141] The 1st die 600 has an outer surface shape corresponding to that of the pressing surface of the 1st punch 500. The pressing surface of the 1st punch 500 has an outer surface shape corresponding to that of the 1st punch bottom surface portion 510, the 1st punch side surface portion 520 and a part of the 1st punch ridge line portion 530, and the 1st punch bottom surface ridge portion 540. That is, the 1st die 600 has a plurality of 1st die side surface portions 620 connected to and rising from a 1st die bottom surface portion 610, and 1st die concave ridge line portions 630 connecting the 1st die side surface portions 620 to each other. Further, in an end portion region 611 of the 1st die bottom surface portion 610 where the 1st die side surface portions 620 rise, there is a 1st die bottom surface concave portion 640 having, in a cross section orthogonal to the pressing surface of the 1st die bottom surface portion 610 and passing through the 1st die concave ridge line portions 630, an overall position connected to the 1st die side surface portions 620 on the 1st die bottom surface portion 610 side and a shape recessed toward the opposite side of the side where the 1st die side surface portions 620 rise and connected to the 1st die bottom surface portion 610. The end portion region 611 is a part of the 1st die bottom surface portion 610 and a region near an edge portion where the 1st die side surface portions 620 and the 1st die concave ridge line portions 630 are connected. The outer surface shape of the 1st die bottom surface concave portion 640 corresponds to that of the 1st punch bottom surface ridge portion 540 and is connected to the 1st die bottom surface portion 610, the 1st die side surface portions 620, and the 1st die concave ridge line portions 630. The overall position of the 1st die bottom surface concave portion 640 is on the 1st die bottom surface portion 610 side than the 1st die side surface portions 620 or the 1st die concave ridge line portions 630. Specifically, the entire range of the 1st die bottom surface concave portion 640 is on the 1st die bottom surface portion 610 side than an imaginary line extending the 1st die side surface portions 620 or the 1st die concave ridge line portions 630 in the above-mentioned cross-sectional observation. The surface of the 1st die bottom surface concave portion 640 is preferably smoothly connected to the 1st die bottom surface portion 610, the 1st die side surface portions 620, and the 1st die concave ridge line portions 630. The 1st die bottom surface concave portion 640 is preferably formed of a curved line in the above-mentioned cross-sectional observation. The 1st die 600 further has a support surface 650, and the 1st die side surface portions 620 and the 1st die concave ridge line portions 630 are connected to the support surface 650 at ends opposite to the ends connected to the 1st die bottom surface concave portion 640 via support ridge line portions 651. The 1st die concave ridge line portions 630 are parts of the 1st die side surface portions 620, and in the present embodiment, the 1st die side surface portions 620 can be replaced with the 1st die concave ridge line portions 630.

[0142] (1st holder)

[0143] The first holder 700 has first holder side portions 720, first holder concave line portions 730 connecting the first holder side portions 720 to each other, and support surfaces 750 that are substantially perpendicular to the first holder side portions 720, and sandwiches the workpiece 1 between the support surfaces 750 and the support surfaces 650 of the first die 600 in a manner that allows the workpiece 1 to move in the in-plane direction thereof. As shown in Figure 14 , the support surfaces 750 of the first holder 700 are disposed at positions opposite the support surfaces 650 of the first die 600. Further, as shown in Figure 12 , the first punch 500 is relatively movable with respect to the first holder 700 within a region surrounded by the first holder side portions 720 and the first holder concave line portions 730 of the first holder 700.

[0144] Next, the operation of the first pressing portion 3000 will be described with reference to a case in which the preform 100 described in the first embodiment is formed by press forming a workpiece. Figure 15 is a cross-sectional view taken along the same plane as Figure 14 . First, as shown in Figure 15 , the workpiece (metal plate) 1 is loaded on the support surfaces 650 of the first die 600 in a state in which the first punch 500 is on the first holder 700 side.

[0145] Next, as shown in Figure 16 , the first holder 700 is relatively moved with respect to the first die 600, and the workpiece 1 is sandwiched by the support surfaces 650 of the first die 600 and the support surfaces 750 of the first holder 700. Then, as shown in Figure 17 , the first punch 500 is relatively moved so as to approach the first die 600, and the workpiece 1 is deformed. The workpiece 1 is sandwiched by the support surfaces 650 of the first die 600 and the support surfaces 750 of the first holder 700 with a force that allows the workpiece 1 to move in the in-plane direction thereof. Therefore, as the first punch 500 and the first die 600 are relatively moved, the workpiece 1 is subjected to a deforming force, and the material constituting the workpiece 1 moves from a range sandwiched by the support surfaces 650 of the first die 600 and the support surfaces 750 of the first holder 700 toward the first die side portions 620 and the first die concave line portions 630 of the first die 600.

[0146] Figure 18 is a schematic cross-sectional view showing a state in which the first punch 500 reaches a lower dead point. When the first punch 500 reaches the lower dead point, the preform 100 is formed. Figure 19 is a schematic cross-sectional view of the preform 100 formed by the first pressing portion 3000 described above. In Figure 19The preform 100 is formed with a preform bottom portion 110, a preform longitudinal wall portion (not shown), a preform ridge line portion 130, a bulging portion 140, and a flange portion 150. The above process corresponds to the preforming process (S1) explained in the first embodiment.

[0147] As above, in the mold of the present embodiment, the preform 100 explained in the first embodiment can be molded. Next, the process of further performing press molding on the thus obtained preform 100 to become a press molded product is explained. The following process corresponds to the official molding process (S2) explained in the first embodiment. In the following process, an example of performing press molding on the preform 100 using the second press portion 4000 provided with a second die and a second punch is explained.

[0148] Figure 20 An example of the second press portion 4000 (official molding mold 20) of the present embodiment is shown. The second press portion 4000 is provided with a second die 800 and a second punch 900 that sandwiches the preform 100 between the second die 800. As shown in Figure 20 , the second die 800 and the second punch 900 are arranged along the press direction P. The second die 800 and the second punch 900 are each relatively movable in the press direction P. In addition, the second die 800 and the second punch 900 can also be relatively movable in a direction other than the press direction P. In addition, the second die 800 and the second punch 900 can each be integral, or can each be capable of being divided. As shown in Figure 20 , the preform 100 is arranged such that the preform bottom portion 110 faces the second die bottom portion 810 side of the second die 800.

[0149] (Second Die)

[0150] Figure 21 An outline plan view of the second die 800 when viewed from the surface side on which the preform 100 is placed in a direction perpendicular to the second die bottom portion 810 is shown. In the second die 800, a second die bottom portion 810, a second die ridge line portion 820, a second die flange portion 830, and a second die side wall portion 840 are formed. Figure 21In the example, the second die 800 has a generally rectangular second die bottom portion 810 on the surface of the die hole. The second die 800 includes the second die bottom portion 810, a plurality of second die side portions (second die first side portion and second die second side portion) 820 connected to and erected from the second die bottom portion 810, and a second die concave ridge portion 830 connecting the second die side portions 820 to each other. The shape of the pressing surface of the second die 800 is preferably such that when the preform 100 is placed in the second die 800, a portion of the preformed longitudinal wall portion 120 of the preform 100 contacts or approaches a portion of the second die side portion 820, and a portion of the preformed ridge portion 130 contacts or approaches a portion of the second die concave ridge portion 830. Furthermore, the die hole can be a closed section hole in which the side surface portion 820 of the second die becomes a closed section in the cross section of the second die 800 parallel to the bottom surface portion 810 of the second die, or an open section hole in which the side surface portion 820 of the second die becomes an open section in the cross section of the second die 800 parallel to the bottom surface portion 810 of the second die.

[0151] Figure 22 Indicates in Figure 21 A schematic cross-sectional view of the second die 800 and the preform 100 placed within the second die 800, viewed from a plane section orthogonal to the bottom surface 810 of the second die at position E-E'. Figure 21 The plane at position E-E' can also be a plane orthogonal to the plate surface of the bottom part 810 of the second die 800 and with an angle equal to the plate surfaces of the respective side parts 820 of the second die connected via the second die concave ridge portion 830. The bottom part 810 of the second die, the side parts 820 of the second die, and the concave ridge portion 830 of the second die are connected by side ridge portions 821. That is, the concave ridge portion 830 of the second die exists between the first side part and the second side part of the second die. Furthermore, the second die 800 has a support surface 850, and the ends of the second die side parts 820 and the concave ridge portion 830 of the second die are connected to the support surface 850 on the opposite side of the end connected to the bottom part 810 of the second die via the support surface ridge portion 851. Figure 22 In this example, a portion of the bulge 140 of the preform 100 is in contact with the pressing surface of the bottom surface 810 of the second die 800; the preform ridge portion 130 is in contact with the concave ridge portion 830 of the second die 800; and the flange portion 150 and the flange ridge portion 151 are in contact with the support surface 850 and the support surface ridge portion 851 of the second die 800. The concave ridge portion 830 of the second die is a part of the side surface portion 820 of the second die, and in this embodiment, the side surface portion 820 of the second die can be replaced by the concave ridge portion 830 of the second die.

[0152] (Second punch)

[0153] Figure 23 Indicates in Figure 21 The diagram shows a schematic cross-sectional view of the second punch 900 approaching the second die 800 at position E-E'. The second punch 900 has an outer surface shape corresponding to the outer surface shape of the pressing surface of the second die 800. The pressing surface of the second punch 900 has an outer surface shape corresponding to the bottom part 810 of the second die, the side part 820 of the second die, and a portion of the concave ridge part 830 of the second die, and the side ridge part 821. That is, the second punch 900 has a plurality of second punch side parts (first side part and second side part of the second punch) 920 connected to and erected from the bottom part 910 of the second punch, and a second punch concave ridge part 930 connecting the second punch side parts 920 to each other. The bottom portion 910 of the second punch is connected to the side portion 920 and the concave ridge portion 930 of the second punch via the side ridge portion 921. Furthermore, the second punch 900 includes a support surface 950, and the side portion 920 and the concave ridge portion 930 are connected to the support surface 950 at the ends opposite to the end connected to the bottom portion 910. The concave ridge portion 930 is a part of the side portion 920 of the second punch, and in this embodiment, the side portion 920 can be replaced by the concave ridge portion 930.

[0154] Figure 24 A schematic cross-sectional view showing the state in which the second punch 900 has moved relative to the second die 800. Figure 25 A schematic cross-sectional view showing the state of the second punch 900 reaching the bottom dead center. When the second punch 900 reaches the bottom dead center, the bulge 140 of the preform 100 is stamped and formed into part of the longitudinal wall 220, the bottom plate 210, and the ridge 230 of the stamped product 200. Figure 26 This represents an example of a stamped part number 200. Figure 26 The stamped product 200 includes a base plate portion 210, a longitudinal wall portion (not shown), a ridge portion 230, a longitudinal wall ridge portion 221, a flange portion 250, and a flange ridge portion 251.

[0155] Specifically, such as Figure 27As shown, the bulging portion 140 of the preform 100 formed by the first punch 500 and the first die 600 is press-formed into the bottom plate portion 210, a portion of the longitudinal wall portion 220 and the ridge line portion 230, and a portion of the longitudinal wall ridge line portion 221 of the press-formed product 200 by the second die 800 and the second punch 900 (the cross section of the press-formed product 200 is indicated by a double dotted line). In the case of manufacturing a product having a shape in which the curvature radius of the ridge line portion is small, as a countermeasure against cracks in the conventional drawing and press-forming process, a method in which the curvature radius of these portions is formed to be large in the first process and the curvature radius is formed to be small in the second process is attempted. However, in the case of manufacturing a product having a shape in which the curvature radius of the ridge line portion is smaller and the forming conditions are more severe, there is a problem in that cracks occur due to a local shortage of material in the second press-forming. In contrast, by using the die of the present embodiment, the preform can be formed while suppressing cracks, and the required material is obtained in the actual forming process. Therefore, cracks and wrinkles can be suppressed in the ridge line portion 230 of the press-formed product 200.

[0156] Further, when the first die bottom surface portion 610 and the second die bottom surface portion 810, the first die concave ridge line portion 630 and the second die concave ridge line portion 830 are overlapped with each other with respect to the first die cross section that passes through the first die first side surface portion and the first die second side surface portion and the second die cross section that passes through the second die first side surface portion and the second die second side surface portion, the first die bottom surface concave portion 640 has a first portion 641 that is positioned on the outside of the second die 800 and is adjacent to the first die concave ridge line portion 630, and a second portion 642 that is positioned on the inside of the second die 800 and is adjacent to the first portion 641.

[0157] Figure 28 A cross-sectional view showing that the first die cross section (solid line) and the second die cross section (double dotted line) are overlapped with each other. In the drawing, Figure 28 the die mold side is set to the outside and the die hole side is set to the inside. The first die bottom surface concave portion 640 has a first portion 641 that is positioned on the outside of the second die 800 and is adjacent to the first die concave ridge line portion 630, and a second portion 642 that is positioned on the inside of the second die 800 and is adjacent to the first die bottom surface portion 610, and the first portion 641 and the second portion 642 are adjacent to each other.

[0158] In addition, in the above description, the first die 600 and the second die 800 are exemplified as being positioned on the lower side, but the present embodiment is not limited thereto, and the first punch 500 can be positioned on the lower side with respect to the first die 600. Further, the press direction is not limited to the vertical direction, and can be the horizontal direction or another direction. Furthermore, the flange portion 150 of the preform 100 and the flange portion 250 of the press-formed product 200 can not be provided.

[0159] In the above example, the distance from the bottom surface 610 of the first die 600 to the support surface 650 in the direction perpendicular to the bottom surface 610 of the first die is shown to be approximately equal to the distance from the bottom surface 810 of the second die 800 to the support surface 850 in the direction perpendicular to the bottom surface 810 of the second die. That is, the distance from the point on the protrusion 140 of the preform 100 furthest from the preform base plate 110 to the flange 150 in the direction perpendicular to the preform base plate 110 is approximately equal to the distance from the base plate 210 of the stamped product 200 to the flange 250 in the direction perpendicular to the base plate 210.

[0160] However, as described in the first embodiment, the flange portion 150 can also be formed in the pre-forming process (S1), and in the formal forming process (S2), the flange portion 150 can be moved relative to the base plate portion 210 so that the flange portion 150 and the base plate portion 210 approach each other in a direction perpendicular to the surface of the base plate portion 210. In this case, as... Figure 29 As shown, the distance from the point furthest from the preform base plate portion 110 of the bulge portion 140 of the preform 100 to the flange portion 150 in the direction perpendicular to the preform base plate portion 110 is set to be greater than the distance from the bottom surface portion 810 of the second die 800 to the support surface 850 in the direction perpendicular to the bottom surface portion 810 of the second die 800. Then, as explained above, as... Figures 30 to 31 That would cause the second punch 900 to move relative to the second die 800.

[0161] like Figure 32 As shown, when the second punch 900 reaches the lower stop point, the bulge 140 of the preform 100 is stamped and formed, and the flange 150 of the preform 100 moves toward the support surface 850 of the second die 800 via the support surface 950 of the second punch 900. At this time, a portion of the preformed longitudinal wall portion 120 and the preformed ridge portion 130 are subjected to deformation force by the second punch side portion 920 of the second punch 900 and the support surface 950, and are clamped by the support surface 850 of the second die 800 and the support surface 950 of the second punch 900, thereby becoming part of the flange 250 of the stamped product 200. Thus, by moving the flange portion 150 relative to the base plate portion 210 so that the flange portion 150 and the base plate portion 210 approach each other in a direction perpendicular to the surface of the base plate portion 210, cracks and wrinkles can be suppressed in the ridge portion 230 of the stamped product 200 after the flange portion 150 is deformed.

[0162] In the press line of the present embodiment, it is also possible that, when the first die bottom surface portion 610 and the second die bottom surface portion 810, and the first die concave ridge line portion 630 and the second die concave ridge line portion 830 are overlapped with each other with respect to the first die cross section and the second die cross section, the second portion 642 has a second A portion on the first portion side from a point where the second portion 642 is deepest, and a second B portion on the central portion side of the first die bottom surface portion 610 from the point, and the smallest radius of curvature of the first portion 641 in the first die cross section and the second A portion is 16 times or more the gap of the first die 600 and the first punch 500.

[0163] By setting the radius of curvature of the inner side surface of the first portion 641 in the above cross section and the second A portion where the curvature is smallest to be 16 times or more the gap of the first die 600 and the first punch 500, it is possible to more stably suppress cracks, and the like. Further, it is more preferable to set the radius of curvature to be 18 times or more the gap of the first die 600 and the first punch 500.

[0164] Further, in the press line of the present embodiment, it is also possible that, when the first die bottom surface portion 610 and the second die bottom surface portion 810, and the first die concave ridge line portion 630 and the second die concave ridge line portion 830 are overlapped with each other with respect to the first die cross section and the second die cross section, the absolute value of the difference between the line length of the first die bottom surface concave portion 640 and the line length of the second die bottom surface portion 810 away from the first die bottom surface concave portion 640 is 4 times or less the gap of the first die 600 and the first punch 500.

[0165] By setting the absolute value of the difference between the line length of the first die bottom surface concave portion 640 and the line length of the second die bottom surface portion 810 away from the first die bottom surface concave portion 640 to be 4 times or less the gap of the first die 600 and the first punch 500, it is possible to more stably suppress cracks and wrinkles of the ridge line portion 230 in the actual molding process, and the like. Further, it is more preferable to set the absolute value of the difference between the line length of the first die bottom surface concave portion 640 and the line length of the second die bottom surface portion 810 away from the first die bottom surface concave portion 640 to be 2 times or less the gap of the first die 600 and the first punch 500.

[0166] Further, in the press line of the present embodiment, it can also be that, when the first die bottom surface portion 610 and the second die bottom surface portion 810, the first die concave line portion 630 and the second die concave line portion 830 are overlapped with each other with respect to the first die cross section and the second die cross section, the distance from the intersection point C of the extension line of the second die bottom surface portion 810 and the extension line of the second die concave line portion 830 to the end portion of the first die bottom surface portion 610 on the side of the second portion 642 is 60 times or less of the gap of the first die 600 and the first punch 500 in the direction perpendicular to the first die bottom surface portion 610 from the intersection point C to the end portion of the first die concave line portion on the side of the first portion 641.

[0167] By setting the distance from the intersection point C of the extension line of the second die bottom surface portion 810 and the extension line of the second die concave line portion 830 to the end portion of the first die bottom surface portion 610 on the side of the second portion 642 to be 60 times or less of the gap of the first die 600 and the first punch 500, it has an effect that the bulging portion 140 can be caused to flow effectively toward the longitudinal wall line portion 221 in the actual molding step. Further, it is more preferable to be 45 times or less. In addition, the lower limit of the distance from the intersection point C of the extension line of the second die bottom surface portion 810 and the extension line of the second die concave line portion 830 to the end portion of the first die bottom surface portion 610 on the side of the second portion 642 is 5 times or more of the gap of the first die 600 and the first punch 500.

[0168] Further, in the press line of the present embodiment, it can also be that, in the cross section of the first die concave line portion 630 parallel to the first die bottom surface portion 610, the radius of curvature of the first die concave line portion 630 is 31 times or less of the gap of the first die 600 and the first punch 500.

[0169] The radius of curvature of the first die concave line portion 630 is the radius of curvature of the surface of the first die concave line portion 630 when viewed from the direction perpendicular to the pressing surface of the first die bottom surface portion 610 of the first die 600 at the boundary of the first die side surface portion 620 or the first die concave line portion 630 and the first die bottom concave portion 640. Further, in the case where the radius of curvature varies in the first die concave line portion 630, it is only necessary to make the radius of curvature 31 times or less of the gap of the first die 600 and the first punch 500 in the entire range.

[0170] The press part of the present embodiment can be favorably used in the manufacturing method of the press-formed product of the first embodiment. That is, a manufacturing method of a press-formed product having a bottom plate portion, a plurality of vertical wall portions connected to the bottom plate portion and standing from the bottom plate portion, and a ridge line portion connecting the vertical wall portions to each other, the manufacturing method of the press-formed product including: a pre-forming step of forming a pre-formed product by press forming a metal sheet, the pre-formed product having a pre-formed bottom plate portion corresponding to the bottom plate portion, a plurality of pre-formed vertical wall portions corresponding to the vertical wall portions and standing from the pre-formed bottom plate portion, and a pre-formed ridge line portion corresponding to the ridge line portion and connecting the pre-formed vertical wall portions to each other; and a main forming step of forming the bottom plate portion, the vertical wall portions, and the ridge line portion by further press forming the pre-formed product, in the pre-forming step, using the first die 600, the first die 600, and the first punch 500, a bulging portion is formed in an end portion region of the pre-formed vertical wall portion standing from the pre-formed bottom plate portion, the bulging portion being such that, in a cross section observation orthogonal to a plate surface of the pre-formed bottom plate portion and passing through the pre-formed ridge line portion, the entire portion is located on a side of the pre-formed bottom plate portion than the pre-formed vertical wall portion and connected to the pre-formed vertical wall portion, and bulges on a side opposite to a side on which the pre-formed vertical wall portion stands and connected to the pre-formed bottom plate portion, in the main forming step, the bulging portion is press formed using the second die 800 and the second punch 900 to be a part of the bottom plate portion and the vertical wall portions. Further, the die of the present embodiment can be provided as a press forming device further having a driving portion (including a cylinder, a hydraulic cylinder, a spring, a cam mechanism, and the like) configured to relatively move the dies to each other. The press forming device can have a control portion for controlling the relative movement of the dies and the operation of the driving portion. The press forming device can be favorably used in the manufacturing method of the press-formed product of the first embodiment.

[0171] In the above embodiment, the thickness of the metal sheet can be an average thickness of the metal sheet as a workpiece. The average thickness can be an average of the thicknesses at a plurality of arbitrary points (for example, three points in a range to be formed as the vertical wall portion or the bottom plate portion) of the metal sheet. Further, the thickness of the metal sheet can be substantially the same as the thickness of the pre-formed vertical wall portion or the pre-formed bottom plate portion of the pre-formed product, or the thickness of the vertical wall portion or the bottom plate portion of the press-formed product. Further, the thickness of the metal sheet can be substantially the same as the gap between the first die and the first holder, or the gap between the second die and the second punch.

[0172] The press-formed product of the above embodiment can be favorably used in vehicle parts such as a battery box having a ridge line portion, a battery box for a vehicle, a lower part of a front pillar, an interior part of a door, and the like. Figures 33 to 36 is a drawing for illustrating an example of a product that can be favorably used in the manufacturing method of the press-formed product of the present embodiment. Figure 33The press-formed product exemplified in (a) of the above is a ridge part 301 of a battery case, having two ridge parts 331 and 331'. Figure 33 The press-formed product exemplified in (b) of the above is a ridge part 302 of a battery case, having a ridge part 332. These press-formed products can be joined with other parts or the like to form the entire battery case. Figure 34 The press-formed product exemplified in the above is a front pillar 303 having a ridge part 333. The present application can also be favorably applied to parts that are bent into an L shape as a whole. Figure 35 The press-formed product exemplified in the above is a reinforcement 304 of a C pillar, in which the vertical wall becomes high near a ridge part 334. In this way, the present application can also be favorably applied to parts in which the height of the vertical wall is not uniform. Figure 36 The press-formed product exemplified in the above is a door inner part 305. The present application can also be favorably applied to press-formed products like the door inner part 305, which has a plurality of ridge parts 335 and 335' having different radii of curvature and opening angles.

[0173] Further, a die is provided, characterized in that a first pressing portion includes a first punch (a second die), a first holder (a third die) that sandwiches a work between the first punch and the first holder, and a first punch (a first die) that sandwiches the work between the first holder in such a manner that the work can move in a surface direction thereof, the first punch includes a first punch bottom surface portion, a plurality of first punch side surface portions (a first punch first side surface portion and a first punch second side surface portion) that are connected to the first punch bottom surface portion and rise from the first punch bottom surface portion, and a first punch concave ridge portion that connects the first punch side surface portions to each other, has a first punch bottom surface recess in an end region of the first punch side surface portion that rises in the first punch bottom surface portion, in which, in a cross section orthogonal to a pressing surface of the first punch bottom surface portion and passing through the first punch concave ridge portion, the first punch bottom surface recess is connected to the first punch side surface portion on a side of the first punch bottom surface portion than the first punch side surface portion and is connected to the first punch bottom surface portion by bulging on a side opposite to the side on which the first punch side surface portion rises, and the first holder has an outer surface shape that corresponds to an outer surface shape of the pressing surface of the first punch.

[0174] In the first pressing portion formed by the above configuration, the first punch bottom surface portion of the first punch has the recess and the first holder has the outer surface shape that corresponds to the outer surface shape of the pressing surface of the first punch, whereby a pre-formed product having a bulging portion can be formed. By press-forming the bulging portion of the pre-formed product into a part of a bottom plate portion and a vertical wall portion of a formed product, a formed product in which cracks and wrinkles are suppressed at a ridge portion can be obtained.

[0175] Embodiment

[0176] Hereinafter, an embodiment of the present application will be described.

[0177] (Example 1)

[0178] In this example, as Experiment Nos. 1 to 9, the preforms having the preform ridge portions as shown in Table 1 below and Figures 37 to 42 were produced, and then each of the preforms was further subjected to press forming to produce press-formed products. The workpiece was a GA270 steel sheet. The plate thickness of the workpiece was 0.8 mm. The high-elongation material was expressed as JAC270F according to the standard for cold-rolled hot-dip galvanized steel sheets for automobiles in the Japan Iron and Steel Federation standards. The low-elongation material was JAC270D in the same standard. The curvature radius Rc of the ridge portion of the preform and the press-formed product was 10 mm, the height of the longitudinal wall of the press-formed product was 100 mm, and the curvature radius Rw of the longitudinal wall ridge portion of the press-formed product was 3 mm. The overall shape of the preform and the press-formed product was the shape as shown in (a) of Figure 1 and (b) of Figure 1 .

[0179] In Table 1, for each of the preforms of Experiment Nos. 1 to 9, the curvature radius Rp from the point at which the bulging portion was connected to the preform longitudinal wall portion to the point farthest from the preform bottom plate portion, the line length difference AL of the preform and the press-formed product, the height el of the bulging portion, and the length e2 of the bulging portion were summarized. In (a) of Figures 37 to 42 , a schematic perspective view of the vicinity of the ridge portion 130 of each preform is shown. In (b) of Figures 37 to 42 , a schematic cross-sectional view of the preform 100 (double-dot chain line) and the press-formed product 200 (solid line) when viewed in the cross section in the plane orthogonal to the plate surface of the preform bottom plate portion 110 and equal to the angle between the plate surfaces of each preform longitudinal wall portion 120 connected via the preform ridge portion 130 is shown.

[0180] [Table 1]

[0181]

[0182] Further, in Table 1, the evaluation results of cracks and wrinkles in each experimental example are shown. As the evaluation results, by visual inspection, the case where the press-formed product had no cracks or wrinkles, the defective product rate was low, and the productivity was high was set to “A (very good)”, the case where there were no cracks or wrinkles was set to “B (good)”, and the case where cracks or wrinkles (including necking, material breakage, and buckling) occurred was set to “C (bad)”.

[0183] In Experiment No. 1, as shown in Figure 37As shown, a preform having the same shape as the above-described stamped product was produced. In other words, the work material was stamped into the shape of the stamped product without being preformed. As shown in Table 1, cracks or wrinkles occurred in both the high-elongation material and the low-elongation material.

[0184] In the preform of Experiment No. 2, as shown in Figure 38 the preform 100 had a ridge line connecting the preform ridge line portion 130 and the preform floor portion 110 located at a position on the inner surface side of the ridge line portion 221 of the stamped product 200. As shown in Table 1, cracks or wrinkles occurred in both the high-elongation material and the low-elongation material.

[0185] In the preform of Experiment No. 3, as shown in Figure 39 the preform 100 had a ridge line connecting the preform ridge line portion 130 and the preform floor portion 110 located at a position on the inner surface side of the ridge line portion 221 of the stamped product 200. As shown in Table 1, cracks or wrinkles occurred in both the high-elongation material and the low-elongation material.

[0186] In the preform of Experiment No. 4, as shown in Figure 40 the preform 100 had a ridge line connecting the preform ridge line portion 130 and the preform floor portion 110 located at a position on the inner surface side of the ridge line portion 221 of the stamped product 200. As shown in Table 1, cracks or wrinkles occurred in both the high-elongation material and the low-elongation material.

[0187] In the preform of Experiment No. 5, as shown in Figure 41 the preform 100 had a ridge line connecting the preform ridge line portion 130 and the preform floor portion 110 located at a position on the inner surface side of the ridge line portion 221 of the stamped product 200. As shown in Table 1, cracks or wrinkles occurred in both the high-elongation material and the low-elongation material.

[0188] In each of the preforms of Experiments No. 6 to No. 9, the basic shape of the bulge portion 140 was Figure 42The shape shown, but the curvature radius Rp, the line length difference AL, the height el and the length e2 of the bulging portion were changed in each preform. In the preform of Experiment No. 6, the bulging portion 140 was located entirely on the side of the preform floor portion 110 than the preform longitudinal wall portion 120 (preform ridge line portion 130), and was bulged to the side opposite to the side on which the preform longitudinal wall portion 120 was erected. As shown in Table 1, no cracks or wrinkles were generated in either the high elongation material or the low elongation material.

[0189] In the preform of Experiment No. 7, the bulging portion 140 was formed in a shape in which it was located entirely on the side of the preform floor portion 110 than the preform longitudinal wall portion 120, and was bulged to the side opposite to the side on which the preform longitudinal wall portion 120 was erected. As shown in Table 1, no cracks or wrinkles were generated in either the high elongation material or the low elongation material. Further, it was found that in the preform of Experiment No. 7, the defective product rate was low and the productivity was high even in the low elongation material. It is considered that the reason for this is that the curvature radius Rp, the line length difference AL, the height el and the length e2 of the bulging portion satisfied the prescribed conditions.

[0190] In the preform of Experiment No. 8, the bulging portion 140 was formed in a shape in which it was located entirely on the side of the preform floor portion 110 than the preform longitudinal wall portion 120, and was bulged to the side opposite to the side on which the preform longitudinal wall portion 120 was erected. As shown in Table 1, no cracks or wrinkles were generated in either the high elongation material or the low elongation material.

[0191] In the preform of Experiment No. 9, the bulging portion 140 was formed in a shape in which it was located entirely on the side of the preform floor portion 110 than the preform longitudinal wall portion 120, and was bulged to the side opposite to the side on which the preform longitudinal wall portion 120 was erected. As shown in Table 1, no cracks or wrinkles were generated in either the high elongation material or the low elongation material.

[0192] (Example 2)

[0193] In this example, as Experiment Nos. 10 to 15, the preforms shown in Table 2 below and Figures 43 to 48Preforms with preformed ridge portions as shown are then further stamped to produce stamped products. In this embodiment, preforms with flange portions having the shapes shown in Table 2 below are manufactured, and then further stamped to produce stamped products. Similar to Example 1, the workpiece material is GA270 steel sheet with a thickness of 0.8 mm. The definitions of high elongation material and low elongation material are the same as in Example 1. Except for the shape of the flange portion, the shapes of the preforms and stamped products adopt the shape of Experiment No. 7 in Example 1. The radius of curvature Rc of the corner portion of the preform and the stamped product is 10 mm, the height of the longitudinal wall of the stamped product is 100 mm, and the radius of curvature Rw of the longitudinal wall ridge portion of the stamped product is 3 mm.

[0194] Table 2 summarizes the distance ΔT that the flange portion moves relative to the base plate portion and the radius of curvature Rd of the flange portion of the preforms during the stamping process from preforms to stamped products for experiments No. 10 to No. 15. Figures 43 to 48 A schematic perspective view of the area near the preformed ridge 130 of each preform is shown in (a). Figures 43 to 48 (b) shows a schematic cross-sectional view of the preform 100 (double-dotted line) and the flange 150 (250) of the stamped product 200 (solid line) when viewed in a plane that is orthogonal to the surface of the preform base plate 110 and forms an angle between the surfaces of the preformed longitudinal wall portions 120 connected via the preformed ridge portion 130.

[0195] [Table 2]

[0196]

[0197] Table 2 shows the evaluation results of cracks and wrinkles in each experimental example. As an evaluation result, by visual inspection, the case where there are no cracks or wrinkles in the flange portion 250 near the edge portion 230 but the productivity is low is marked as "B (good)", and the case where cracks or wrinkles (including necking, material fracture, buckling) occur is marked as "C (bad)".

[0198] like Figure 43 As shown, in the preform of Experiment No. 10, when the preform 100 is stamped to form the stamped product 200, the height of the flange portion and the radius of curvature Rd of the flange edge portion 151 are not changed. As shown in Table 2, cracks or wrinkles are generated in both high elongation and low elongation materials.

[0199] like Figure 44As shown, in the preform of Experiment No. 11, the radius of curvature Rd of the flange edge portion 151 of the preform 100 was set to be greater than the radius of curvature Rf of the flange edge portion 251 of the stamped product 200. However, when the preform 100 was stamped to form the stamped product 200, the height of the flange portion was not changed. As shown in Table 2, cracks or wrinkles were generated in both high elongation and low elongation materials.

[0200] like Figure 45 As shown, in the preform of Experiment No. 12, the radius of curvature Rd of the flange edge portion 151 of the preform 100 was set to be greater than the radius of curvature Rf of the flange edge portion 251 of the stamped product 200. When the preform 100 was stamped to form the stamped product 200, the flange portion 150 was moved relative to the base plate portion 210 so that the flange portion 150 and the base plate portion 210 approached each other in a direction perpendicular to the surface of the base plate portion 210. As shown in Table 2, cracks or wrinkles were generated in both high elongation and low elongation materials. It can be assumed that the reason is that, due to the excessively large ΔT, the remaining material is concentrated in the flange portion 150.

[0201] like Figure 46 As shown, in Experiment No. 13, when the preform 100 is stamped to form the stamped product 200, the flange portion 150 is moved relative to the base plate portion 210 so that the flange portion 150 and the base plate portion 210 approach each other in a direction perpendicular to the surface of the base plate portion 210. Furthermore, the radius of curvature Rd of the flange edge portion 151 of the preform 100 is set to be greater than the radius of curvature Rf of the flange edge portion 251 of the stamped product 200. As shown in Table 2, no cracks or wrinkles were generated in the high elongation material.

[0202] like Figure 47 As shown, in the preform of Experiment No. 14, when the preform 100 is stamped to form the stamped product 200, the flange portion 150 is moved relative to the base plate portion 210 so that the flange portion 150 and the base plate portion 210 approach each other in a direction perpendicular to the surface of the base plate portion 210. Furthermore, the radius of curvature Rd of the flange edge portion 151 of the preform 100 is set to be greater than the radius of curvature Rf of the flange edge portion 251 of the stamped product 200. As shown in Table 2, no cracks or wrinkles were generated in the high elongation material.

[0203] like Figure 48As shown, in the preform of Experiment No. 15, when the preform 100 was subjected to press forming to form a press-formed product 200, the flange portion 150 was relatively moved with respect to the bottom plate portion 210 to bring the flange portion 150 and the bottom plate portion 210 close to each other in a direction perpendicular to the plate surface of the bottom plate portion 210. Further, the curvature radius Rd of the flange ridge portion 151 of the preform 100 was set within a prescribed range. As shown in Table 2, no cracks or wrinkles were generated in either the high elongation material or the low elongation material.

[0204] Industrial applicability

[0205] The method for manufacturing a press-formed product and the press production line according to the present application can obtain a product in which cracks or wrinkles are suppressed in the ridge portion, and thus are extremely useful in industry.

[0206] Explanation of symbols

[0207] 1: material to be processed; 10: preforming die; 20: final forming die; 100: preform; 110: preform bottom plate portion; 111: end portion region; 120: preform vertical wall portion; 121: base end portion; 122: front end portion; 130: preform ridge portion; 140: bulging portion; 150: flange portion; 151: flange ridge portion; 200: press-formed product; 210: bottom plate portion; 221: vertical wall ridge portion; 220: vertical wall portion; 230: ridge portion; 300: product; 500: first punch; 510: first punch bottom surface portion; 520: first punch side surface portion; 530: first punch convex ridge portion; 540: first punch bottom surface convex portion; 600: first die; 700: first holder; 800: second die; 900: second punch.

Claims

1. A method for manufacturing a stamped product, characterized in that, have: The steps of stamping a metal sheet into a preform; and The step of stamping the above preform into a stamped product. The above-mentioned preforms have the following characteristics: Preformed base plate section; First preformed longitudinal wall section; Second preformed longitudinal wall section; The preformed ridge portion is located between the first preformed longitudinal wall portion and the second preformed longitudinal wall portion; and The bulge portion is located between the preformed bottom plate portion and the first preformed longitudinal wall portion and the second preformed longitudinal wall portion; The above-mentioned stamped products have the following characteristics: Base plate; The first longitudinal wall portion is adjacent to the aforementioned bottom plate portion; The second longitudinal wall portion is adjacent to the aforementioned bottom plate portion; and The ridge portion is located between the first longitudinal wall portion and the second longitudinal wall portion. When the preform section passing through the middle of the first preformed longitudinal wall and the second preformed longitudinal wall and the stamped section passing through the middle of the first longitudinal wall and the second longitudinal wall, respectively, the preformed base plate section overlaps with the base plate section and the preformed ridge section overlaps with the ridge section, The aforementioned bulge portion comprises: a first portion located inside the stamped article and adjacent to the pre-formed ridge portion; and a second portion located outside the stamped article and adjacent to the pre-formed base plate portion. Part 1 above is adjacent to Part 2 above.

2. The method for manufacturing stamped articles according to claim 1, wherein, The second part described above includes: a second part A, which is closer to the first part than the point in the second part that is furthest from the preformed base plate in the thickness direction; and a second part B, which is closer to the preformed base plate than the aforementioned point. The radius of curvature of the inner surface of the smallest bend in the first part and the second part of the preform cross section is more than 15 times the thickness of the metal plate.

3. The method for manufacturing stamped articles according to claim 1 or 2, wherein, When the preformed base plate portion overlaps with the preformed base plate portion and the preformed ridge portion overlap with the ridge portion for the cross-section of the preformed product and the cross-section of the stamped product, respectively. The absolute value of the difference between the linear length of the aforementioned bulge and the linear length of the portion of the aforementioned stamped product that is far away from the aforementioned bulge is less than 4 times the thickness of the aforementioned metal sheet.

4. The method for manufacturing a stamped article according to claim 1 or 2, wherein, When the preformed base plate portion overlaps with the preformed base plate portion and the preformed ridge portion overlap with the ridge portion for the cross-section of the preformed product and the cross-section of the stamped product, respectively. The distance from the intersection (C) of the extension line of the base plate portion and the extension line of the ridge portion to the preformed base plate portion is less than 60 times the thickness of the metal plate, and the distance from the intersection (C) to the preformed ridge portion in the direction perpendicular to the base plate portion is less than 60 times the thickness of the metal plate.

5. The method for manufacturing a stamped article according to claim 1, wherein, The preform described above has a flange portion adjacent to the end of the preformed ridge portion. When the preformed base plate portion overlaps with the preformed base plate portion and the preformed ridge portion overlap with the ridge portion for the cross-section of the preformed product and the cross-section of the stamped product, respectively. The flange portion of the stamped article is located on the side closer to the base plate portion than the flange portion of the preformed article.

6. The method for manufacturing a stamped article according to claim 5, wherein, When the preformed base plate portion overlaps with the preformed base plate portion and the preformed ridge portion overlap with the ridge portion for the cross-section of the preformed product and the cross-section of the stamped product, respectively. The flange portion of the stamped article moves a distance of more than 2 times and less than 30 times the thickness of the metal plate from the flange portion of the preformed article in the vertical direction of the base plate portion.

7. The method for manufacturing a stamped article according to claim 5 or 6, wherein, In the cross-section of the preform, the radius of curvature of the inner curved surface of the flange ridge between the flange portion and the preformed ridge portion of the preform is more than 6 times and less than 30 times the thickness of the metal plate.

8. The method for manufacturing a stamped article according to claim 5 or 6, wherein, In the cross-section of the stamped product described above, the radius of curvature of the curved inner surface of the flange edge is less than 10 times the thickness of the metal sheet.

9. The method for manufacturing a stamped article according to claim 1 or 2, wherein, In the cross section passing through the aforementioned ridge portion parallel to the aforementioned base plate portion, the radius of curvature of the inner side of the curved ridge portion is less than 30 times the thickness of the aforementioned metal plate.

10. The method for manufacturing a stamped article according to claim 1 or 2, wherein, The cross section of the stamped article having the first longitudinal wall portion, the second longitudinal wall portion, and the ridge portion and being parallel to the bottom plate portion is a closed cross section.

11. A stamping production line, comprising: The first stamping section includes a first die, a first punch, and a first support; and The second stamping section includes a second die and a second punch. The surface of the die hole of the first die has a bottom part, a first side part, a second side part, and a concave edge part. The aforementioned concave ridge of the first die is located between the first side surface of the first die and the second side surface of the first die. At the portion of the bottom surface of the first die that is adjacent to the end of the concave ridge of the first die, there is a portion of the bottom surface of the first die that is recessed compared to the central portion of the bottom surface of the first die. The surface of the die hole of the second die has a bottom part of the second die, a first side part of the second die, a second side part of the second die, and a concave edge part of the second die. The aforementioned concave ridge of the second die is located between the first side surface of the second die and the second side surface of the second die. When the first die cross-section passing through the middle of the first side surface of the first die and the second side surface of the first die, and the second die cross-section passing through the middle of the first side surface of the second die and the second side surface of the second die, respectively overlap the bottom surface of the first die and the bottom surface of the second die, and the concave edge of the first die and the concave edge of the second die, The first die bottom recess includes: a first portion located outside the second die and adjacent to the first die recess ridge; and a second portion located inside the second die and adjacent to the first portion.

12. The stamping production line according to claim 11, wherein, When the bottom surface of the first die and the bottom surface of the second die, and the concave edge of the first die and the concave edge of the second die are respectively overlapped for the first die section and the second die section, The second part described above includes: a second A part, located closer to the first part than the point where the deepest recess in the second part is; and a second B part, located closer to the center of the bottom surface of the first die than the aforementioned point. The minimum radius of curvature of the first part and the second part of the first die section is more than 16 times the gap between the first die and the first punch.

13. The stamping production line according to claim 11 or 12, wherein, When the bottom surface of the first die and the bottom surface of the second die, and the concave edge of the first die and the concave edge of the second die are respectively overlapped for the first die section and the second die section, The absolute value of the difference between the line length of the recessed part of the bottom surface of the first die and the line length of the bottom surface of the second die that is far away from the recessed part of the bottom surface of the first die is less than 4 times the gap between the first die and the first punch.

14. The stamping production line according to claim 11 or 12, wherein, When the bottom surface of the first die and the bottom surface of the second die, and the concave edge of the first die and the concave edge of the second die are respectively overlapped for the first die section and the second die section, The distance from the intersection (C) of the extension line of the bottom surface of the second die and the extension line of the concave edge of the second die to the end of the bottom surface of the first die in the second part is less than 60 times the gap between the first die and the first punch. The distance from the intersection point (C) to the end of the first die concave ridge side of the first part of the above-mentioned part in the direction perpendicular to the bottom surface of the first die is less than 60 times the gap.

15. The stamping production line according to claim 11 or 12, wherein, In the cross-section passing through the concave ridge of the first die, which is parallel to the bottom surface of the first die. The radius of curvature of the concave edge of the first die is less than 31 times the gap between the first die and the first punch.

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