Method for manufacturing stamped product, stamping device and stamping production line

Abstract

A method for manufacturing a stamped product, the manufacturing method comprising the following steps: constraining the first surface of an intermediate formed product having a first surface, a raised surface, and a first ridgeline located between the first surface and the raised surface; and performing flange forming by stamping the raised surface into a second surface, a flange, and a second ridgeline located between the second surface and the flange, wherein when viewed from the stamping direction of the stamping forming, the first ridgeline extends convexly and curvedly in a direction from the raised surface toward the first surface, the second ridgeline extends convexly and curvedly in a direction from the flange toward the second surface, and a direction along the stamping direction intersecting the first ridgeline is formed. The protruding direction of the first edge line in the cross section and the protruding direction of the second edge line in the cross section along the stamping direction intersecting the second edge line are on the same side, the curvature radius of the extension direction of the first edge line at the intersection of the first edge line of the intermediate formed product and the straight line orthogonal to the second edge line is larger than the curvature radius of the extension direction of the second edge line on the straight line after the flange forming process, and the angle formed by the second surface at the position corresponding to the first edge line after the flange forming process is larger than the angle formed by the raised surface adjacent to the first edge line in the intermediate formed product.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a stamped product having a portion formed by stretching a flange, a stamping device, and a stamping production line. Background Art

[0002] Due to the stricter fuel consumption regulations in recent years, the weight reduction of automobile bodies is sought, and the weight reduction of each component constituting the body is also required. However, simply replacing the material of the component with a high-strength and thinner material may lead to a decrease in rigidity, so it is expected to meet the weight reduction requirements by improving the shape and structure of the component together with the high strength of the material.

[0003] Figure 1 The figure shows the body frame of a car. In the body frame of a car, for example, there are places where parts such as the front longitudinal beam, the rear longitudinal beam, and the cross beam are connected to other parts. In this joint part, sometimes, Figure 2 In this way, the first component 80 and the second component 81 are fixed in a letter T shape. In this example, the first component 80 has a first flange 82a and a second flange 82b extending in different directions from each other, and the first flange 82a and the second flange 82b are respectively joined to the second component 81 by welding. Figure 2 In the example of FIG. 1 , the first flange 82a and the second flange 82b are not continuously connected, but from the perspective of improving the collision performance and rigidity of the vehicle body, it is preferred to Figure 3 The first flange 82a and the second flange 82b are continuously connected as shown in the portion surrounded by the dotted line in FIG.

[0004] However, in the case of manufacturing a component having a shape in which the first flange 82a and the second flange 82b are continuously connected, if the blank is formed in a manner of standing up, tensile stress is generated in the third flange 82c between the first flange 82a and the second flange 82b, and tensile strain is generated during forming. That is, the third flange 82c is formed with so-called extended flange deformation. The difficulty of forming a component having a portion (hereinafter referred to as an "extended flange portion") that produces such an extended flange deformation increases, and cracks such as the top end of the flange are easily generated in the extended flange portion. In particular, when the material of the component is a high-strength material such as a high-tensile steel material, the difficulty of forming with extended flange deformation further increases.

[0005] As a method for manufacturing a component having an extended flange portion, Patent Document 1 discloses a stamping forming method having a first forming step of forming an intermediate formed product and a second forming step of forming a flange in the shape of a product from the intermediate formed product. In the first forming step of Patent Document 1, a mountain-shaped portion protruding from the top plate portion side is formed on the flange surface of the intermediate formed product, and in the subsequent second forming step, the height of the flange is increased to form a flange in the shape of a product. Patent Document 2 discloses the following: when the top plate portion is bent to form the flange, the top plate portion is pressed at a position away from the outer peripheral edge of the top plate portion, and the flange is formed in this state. Patent Document 3 discloses the following method: a convex portion is provided on a metal sheet by bulging, and then wrinkles are generated on the plate surface at the base end of the convex portion by drawing, and then a hole portion is formed on the top surface of the convex portion by punching.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 5510533

[0009] Patent Document 2: Japanese Patent Application Publication No. 2015-100812

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 4-031773 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] In the forming methods of Patent Documents 1 and 2, when forming a flange in a product shape, in order to ensure the height of the flange, it is necessary to process the blank so that it extends in the height direction of the flange, and the tensile strain suppression effect of the top end of the flange is small. In the forming method of Patent Document 3, wrinkles are generated at the root of the flange, so the use as a component is limited. Therefore, in a component with an extended flange portion, a new forming method for suppressing tensile strain to manufacture the component is sought.

[0013] The present disclosure is an invention made in view of the above circumstances, and an object of the present invention is to suppress tensile strain generated in the flange when manufacturing a press-formed product having an extended flange portion.

[0014] Solutions for solving problems

[0015] A technical solution disclosed in the present invention for solving the above-mentioned problem is a method for manufacturing a stamped product, which has the following steps: constraining the first surface of an intermediate formed product having a first surface, a raised surface, and a first ridge line located between the first surface and the raised surface; and performing flange forming to stamp the raised surface into a second surface, a flange, and a second ridge line located between the second surface and the flange, wherein when viewed from the stamping direction of the stamping forming, the first ridge line extends convexly and curvedly in a direction from the raised surface toward the first surface, and the second ridge line extends convexly and curvedly in a direction from the flange toward the second surface, along a direction parallel to the first ridge line. The convex direction of the first ridge line in the cross section along the stamping direction where the line intersects and the convex direction of the second ridge line in the cross section along the stamping direction intersecting the second ridge line are on the same side, the curvature radius of the extension direction of the first ridge line at the intersection of the first ridge line of the intermediate formed product and the straight line orthogonal to the second ridge line is larger than the curvature radius of the extension direction of the second ridge line on the straight line after the flange is formed, and the angle formed by the second surface at the position corresponding to the first ridge line after the flange is formed is larger than the angle formed by the raised surface adjacent to the first ridge line in the intermediate formed product and the first surface.

[0016] A technical solution of the present disclosure based on another viewpoint is a stamping forming device, which includes a punch, a die and a pad, wherein the punch includes a punch longitudinal wall portion, a punch bottom portion and a concave ridge line portion located between the punch longitudinal wall portion and the punch bottom portion, the die includes a die longitudinal wall portion, a die bottom portion and a die shoulder ridge line portion located between the die longitudinal wall portion and the die bottom portion, and the pad includes a pad longitudinal wall portion, a pad bottom portion and a pad ridge line portion located between the pad longitudinal wall portion and the pad bottom portion, and when viewed along the stamping direction, the pad ridge line portion extends convexly and curvedly in a direction from the die toward the pad, and when viewed along the stamping direction, When observed in the stamping direction, the die shoulder ridge portion extends convexly and curvedly in the direction from the punch longitudinal wall portion toward the die longitudinal wall portion, the pad longitudinal wall portion is arranged adjacent to the die, at the lower dead point of forming, the punch longitudinal wall portion is relatively adjacent to the die longitudinal wall portion, at the lower dead point of forming, the punch bottom surface portion is relatively adjacent to the die bottom surface portion, at the lower dead point of forming, the pad bottom surface portion is relatively adjacent to the punch bottom surface portion, and the curvature radius of the extension direction of the pad ridge portion at the intersection of the pad ridge portion on a straight line orthogonal to the second ridge line and the straight line is larger than the curvature radius of the extension direction of the die shoulder ridge portion on the straight line.

[0017] In addition, a technical solution of the present disclosure based on another viewpoint is a stamping forming production line, which includes a preforming device and the stamping forming device, the preforming device includes a preforming punch and a preforming die, the preforming punch includes a preforming punch longitudinal wall portion, a preforming punch bottom portion and a preforming punch concave ridge line portion located between the preforming punch longitudinal wall portion and the preforming punch bottom portion, the preforming die includes a preforming die longitudinal wall portion, a preforming die bottom portion and a preforming die shoulder ridge line portion located between the preforming die longitudinal wall portion and the preforming die bottom portion, when observed along the stamping direction, the preforming die shoulder ridge line portion extends convexly and curved in the direction from the preforming punch longitudinal wall portion toward the preforming die longitudinal wall portion, and at the lower dead point of the forming, the preforming punch longitudinal wall portion and the preforming die longitudinal wall portion are aligned. The wall portions are relatively adjacent to each other, and at the lower dead point of forming, the bottom surface portion of the preforming punch is relatively adjacent to the bottom surface portion of the preforming die, the radius of curvature of the extension direction of the preforming die shoulder ridge portion at the intersection of the preforming die shoulder ridge portion and a straight line that is orthogonal to the die shoulder ridge portion of the stamping forming device and intersects the preforming die shoulder ridge portion of the preforming device is larger than the radius of curvature of the extension direction of the die shoulder ridge portion on the straight line, and in the cross section along the stamping direction intersecting the preforming die shoulder ridge portion of the preforming die of the preforming device and the pad ridge portion of the pad of the stamping forming device, the angle formed by the die bottom surface portion adjacent to the pad ridge portion and the pad bottom surface portion is larger than the angle formed by the preforming die longitudinal wall portion adjacent to the preforming die shoulder ridge portion and the preforming die bottom surface portion.

[0018] Effects of the Invention

[0019] According to the present disclosure, when a press-formed product having an extended flange portion is manufactured, tensile strain generated in the flange can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram showing an example of a vehicle body frame.

[0021] Figure 2 This is a diagram showing an example of the joint shape of the joining portion between the first member and the second member.

[0022] Figure 3 This is a diagram showing an example of the joint shape of the joining portion between the first member and the second member.

[0023] Figure 4 This is a diagram showing an example of a press-formed product having an extended flange portion.

[0024] Figure 5It is a diagram showing the shape of a press-formed product having an extended flange portion during the manufacturing process according to one embodiment of the present disclosure. Figure 5 (a) represents the shape of the blank, Figure 5 (b) shows the shape of the intermediate molded product after the pre-molding process. Figure 5 (c) shows the shape of the stamped product after the forming process.

[0025] Figure 6 It is a diagram showing an example of arrangement of a preforming device and a press forming device in a press forming line.

[0026] Figure 7 It is a diagram showing a configuration example of a preforming device in a preforming step.

[0027] Figure 8 It is a diagram showing a punch (preforming punch) of a preforming device.

[0028] Fig. 9 It is a figure which shows the cross section of the preforming device in the punching direction.

[0029] Fig.10 It is a diagram showing the forming process of an intermediate molded product in the preforming step.

[0030] Fig.11 Yes means Figure 5 (b) is a diagram of the AA section. In addition, Fig.11 The two-dot chain line in denoted the shape of the press-formed product after the flange forming step.

[0031] Fig.12 This is a diagram for explaining each forming section of a preforming device. In this figure, hatching indicating a cross section is omitted.

[0032] Fig.13 It is a diagram showing a configuration example of a press forming device in a flange forming step.

[0033] Fig.14 It is a figure which shows the punch of a press forming device.

[0034] Fig.15 It is a diagram showing a cross section of the press forming device in the press direction.

[0035] Fig.16 It is a diagram showing the forming process of a press-formed product in the flange forming step.

[0036] Fig.17 Yes means Figure 5 (c) is a diagram of the BB cross section. In addition, Fig.17 The two-dot chain line in represents the shape of the intermediate molded product after the preforming step.

[0037] Fig.18 This is a diagram for explaining each forming section of a press forming device. In this figure, hatching indicating a cross section is omitted.

[0038] Fig.19 This is a top view of the intermediate molded product.

[0039] Fig. 20 It is a plan view schematically showing each forming section of the preforming device.

[0040] Fig.21 It is a diagram showing the shape of a component during the manufacturing process of a press-formed product having an extended flange portion according to another embodiment of the present invention. Fig.21 (a) represents the shape of the blank, Fig.21 (b) shows the shape of the intermediate molded product after the pre-molding process. Fig.21 (c) shows the shape of the stamped product after the trimming process. Fig.21 (d) shows the shape of the press-formed product after the flange forming step.

[0041] Fig. 22 It is a diagram showing an example of the configuration of a press forming line.

[0042] Fig.23 This is a diagram showing the distribution of the change in plate thickness of the press-formed product after the flange forming step of Comparative Example 1.

[0043] Fig.24 This is a diagram showing the distribution of the change in plate thickness of the press-formed product after the flange forming step of Example 1.

[0044] Fig.25 This is a diagram showing the distribution of the change in plate thickness of the press-formed product after the flange forming step of Example 2.

[0045] Fig.26 It is a diagram showing the magnitude of the circumferential strain at a position in the horizontal direction from the flange.

[0046] Fig. 27 It is a diagram showing simulation results of the analysis model with different L1 / L2.

[0047] Fig.28 It is a diagram showing simulation results of analysis models with different R3 / R2.

[0048] Fig.29 It is an explanatory diagram of the influence on the second surface of the stamped product when the raised surface of the intermediate formed product is formed in a manner that becomes a curved surface convex toward the stamping direction and when the raised surface of the intermediate formed product is formed in a manner that becomes a curved surface convex toward the direction opposite to the stamping direction. DETAILED DESCRIPTION

[0049] Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings. In addition, in the present specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals to omit repeated descriptions.

[0050] In this embodiment, as an example of a press-formed product having an extended flange portion, Figure 4 A method for forming a stamped product 1 of a shape such as that described above is described below. The stamped product 1 comprises: a flat surface (second surface) 2; a flange 3 formed by bending and extending a portion of the surface 2 in a direction intersecting the surface 2 (upward in the figure); and a ridge (second ridge) 4 connecting the surface 2 and the flange 3. The edge of the flat surface 2 is partially bent upward by stamping, thereby forming the flange 3. The ridge 4 exists continuously between the surface 2 and the flange 3. The flange 3 is bent in a manner convex to the inside of the surface 2 when viewed from above in the direction of the plate thickness of the surface 2, and an extended flange deformation occurs during forming. In the present embodiment, by Figure 5 The flat blank 10 having a curved notch 10a as shown in (a) is formed. Figure 5 The preforming step of the intermediate molded product 11 as in (b) and the forming step of the intermediate molded product 11 Figure 5 The stamped product 1 is manufactured by the flange forming step of the flange 3 as in (c). Figure 5 The two sides of the notch 10a are not connected, but the notch 10a can also be annular. That is, the notch 10a can also be a hole. In other words, the notch 10a can only be Figure 5 The parts shown in Figure 5 The same structure is arranged outside the structure depicted in the figure, with the inner corner of the center as the center. Fig.13 , Fig.14 , Fig.19 , Fig. 20 , Fig.21 , Fig.23 , Fig.24 , Fig.25 The material of the blank 10 is not particularly limited, and for example, a metal plate such as a steel plate, an aluminum alloy plate, or a magnesium alloy plate can be used.

[0051] <Preforming process>

[0052] like Figure 5As shown in (b), the intermediate formed product 11 manufactured by the preforming process has: a first surface 12 in a flat plate shape; a raised surface 13, which is a surface raised relative to the first surface 12 formed in a manner that a portion including the notch 10a of the blank 10 is raised upward in the figure; and a first ridgeline 14, which is located between the first surface 12 and the raised surface 13. When viewed from above, the first ridgeline 14 extends in a convex and curved direction from the raised surface 13 toward the first surface 12. Hereinafter, the top view will be expressed as a top view observed along the punching direction, but the meaning is the same when viewed from above along the thickness direction of the first surface 12. The raised surface 13 is formed by punching the blank 10.

[0053] Such an intermediate molded product 11 is used, for example, Figure 6 The preforming device 30 of the stamping forming production line 20 shown is manufactured. Figure 6 In the example, the stamping forming production line 20 includes a preforming device 30 for forming an intermediate formed product 11 from a blank 10, and a stamping forming device 40 for forming a stamped product 1 from the intermediate formed product 11. The preforming device 30 and the stamping forming device 40 are arranged close to each other, and the blank 10 is continuously stamped. Alternatively, the preforming device 30 and the stamping forming device 40 may be arranged at positions separated from each other. In such a case, for example, the intermediate formed product 11 formed by the preforming device 30 is temporarily stored in advance, and after the inventory of the intermediate formed product 11 reaches a predetermined amount, the stored intermediate formed products 11 are collected and transported to the stamping forming device 40, and each intermediate formed product 11 is stamped one by one in the stamping forming device 40.

[0054] Figure 7 to Figure 9 3 is a diagram showing a configuration example of a preforming device 30 according to this embodiment. Figure 7 Only the lower surface shape of the preforming die 33 is shown. Figure 7 and Figure 8 Only the shape of the upper surface of the preliminary forming punch 31 is shown. The upper surface of the preliminary forming punch 31 and the lower surface of the preliminary forming die 33 are punching surfaces (forming portions) for forming the intermediate formed product 11 from the blank 10.

[0055] like Figure 7As shown, the preforming device 30 of the present embodiment includes a preforming punch 31, a preforming pad 32, and a preforming die 33. The preforming punch 31 includes: a preforming punch bottom portion 31a; a preforming punch top portion 31b, which is located at a different height from the preforming punch bottom portion 31a (above the preforming punch bottom portion 31a in this embodiment); and a punch inclined surface 31c, which connects the preforming punch bottom portion 31a with the preforming punch top portion 31b. The preforming punch bottom portion 31a and the preforming punch top portion 31b of the preforming punch 31 of the present embodiment are parallel to each other, but may not be parallel. In addition, as Figure 8 As shown, a part of the inclined surface 31c of the preforming punch becomes a preforming punch longitudinal wall portion 31c' having a curvature like the side surface of a truncated cone. The preforming punch longitudinal wall portion 31c', when viewed from above along the punching direction, becomes a curved shape that bulges in the direction from the preforming punch top surface portion 31b toward the preforming punch bottom surface portion 31a. That is, the surface of the preforming punch longitudinal wall portion 31c' is convexly curved. A concave ridge line portion 31d is formed between the preforming punch longitudinal wall portion 31c' and the preforming punch bottom surface portion of the preforming punch inclined surface 31c. Similarly, the concave ridge line portion 31d, when viewed from above along the punching direction, becomes a curved shape that bulges in the direction from the preforming punch top surface portion 31b toward the preforming punch bottom surface portion 31a.

[0056] The preforming pad 32 is configured to be able to rise and fall at a position opposite to the preforming punch top surface 31b of the preforming punch 31. The preforming die 33 has a preforming die bottom surface 33a opposite to the preforming punch bottom surface 31a of the preforming punch 31 and a preforming die inclined surface 33b opposite to the preforming punch inclined surface 31c of the preforming punch 31. Similar to the preforming punch longitudinal wall portion 31c' of the preforming punch inclined surface 31c, a part of the preforming die inclined surface 33b becomes a preforming die longitudinal wall portion 33b' having a curvature. The preforming die longitudinal wall portion 33b' has a curved shape that convexly moves from the preforming die inclined surface 33b toward the preforming die bottom surface 33a when viewed from above along the punching direction. That is, the surface of the preforming die longitudinal wall portion 33b' is convexly curved. The preforming die shoulder ridge line portion 33c is located between the preforming die longitudinal wall portion 33b' of the preforming die inclined surface 33b and the preforming die bottom surface portion 33a. Similarly, the preforming die shoulder ridge line portion 33c, when viewed from above along the punching direction, is in a curved shape that bulges from the preforming die inclined surface 33b toward the preforming die bottom surface portion 33a. The preforming die 33 is configured to be able to be raised and lowered on the side of the preforming pad 32. In addition, the structure of the preforming device 30 is appropriately changed according to the product shape of the stamped product 1, and the processing method that can be adopted is also appropriately changed according to the product shape of the stamped product 1.

[0057] In the preforming process using the preforming device 30, first, Figure 7 and Fig.10 As in (a), the preforming pad 32 is used to press the portion of the blank 10 around the notch 10a, and the preforming die 33 is lowered in this state. Fig.10 By sandwiching the portion of the blank 10 around the notch 10a between the top surface 31b of the preforming punch and the lower surface of the preforming pad 32 as in (a), the blank 10 can be arranged between the upper surface of the preforming punch 31 and the lower surface of the preforming die 33.

[0058] In this way, the blank 10 is arranged between the upper surface of the preforming punch 31 and the lower surface of the preforming die 33. Fig.10 As shown in (b), the preforming die 33 is lowered. At the lower dead point of the forming process in which the preforming die 33 is lowered, the preforming punch longitudinal wall portion 31c' is relatively adjacent to the preforming die longitudinal wall portion 33b', and the preforming punch bottom surface portion 31a is relatively adjacent to the preforming die bottom surface portion 33a. In addition, at the lower dead point of the forming process in which the preforming die 33 is lowered, when viewed from above along the punching direction, the preforming die shoulder ridge line portion 33c and the concave ridge line portion 31d are in a state of extending in a convex manner from the preforming punch longitudinal wall portion 31c' toward the preforming die longitudinal wall portion 33b'.

[0059] The preforming die 33 is lowered to the lower dead point of the forming process, so that the preforming punch longitudinal wall portion 31c' of the preforming punch 31 and the preforming die longitudinal wall portion 33b' of the preforming die 33 are used for stamping, and a local area of ​​the blank 10 becomes like Fig.10 (b) is a raised shape, shaped like Fig.11 The intermediate formed product 11 shown has a first surface 12, a raised surface 13, and a first ridge line 14. A portion of the flat first surface 12 is bent upward by stamping in the pre-forming process, thereby forming the raised surface 13. In the intermediate formed product 11, the first ridge line 14 exists continuously between the first surface 12 and the raised surface 13. When viewed from above along the stamping direction, the first ridge line 14 extends in a curved shape that is convexly bent from the raised surface 13 toward the first surface 12. In addition, in a cross section in the stamping direction intersecting the first ridge line 14, the first ridge line 14 is directed obliquely downward (at Fig.11 The height of the raised surface 13 is the height from the first surface 12 in the plate thickness direction of the first surface.

[0060] In this way, the first surface 12, the raised surface 13 and the first ridge line 14 of the intermediate molded product 11 are formed by the preforming device 30, so that Fig.12As shown, the preforming device 30 includes: a first surface forming portion 35, which is a portion of the first surface 12 of the intermediate molded product 11; a raised surface forming portion 36, which is a portion of the raised surface of the intermediate molded product 11 raised relative to the first surface forming portion 35; and a first ridge line forming portion 37, which is a portion of the first ridge line 14 of the intermediate molded product 11 that connects the first surface forming portion 35 and the raised surface forming portion 36. The first surface forming portion 35 is formed between the preforming punch bottom surface portion 31a of the preforming punch 31 and the preforming die bottom surface portion 33a of the preforming backing plate 32. The raised surface forming portion 36 is formed between the preforming punch vertical wall portion 31c' of the preforming punch 31 and the preforming die vertical wall portion 33b' of the preforming backing plate 32. The first ridge line forming portion 37 is formed between the concave ridge line portion 31d of the preforming punch 31 and the preforming die shoulder ridge line portion 33c of the preforming die 33. In addition, if Figure 5 The first surface 12 shown in (b) of FIG. 1 is formed by the first surface forming portion 35, and thus the first surface forming portion 35 has a portion of the edge adjacent to the first ridge line forming portion 37, which is bent toward the inside of the first surface forming portion 35, and the raised surface forming portion 36 is provided adjacent to the bent portion of the first surface forming portion 35. That is, the first ridge line forming portion 37 is located between the raised surface forming portion 36 and the first surface forming portion 35.

[0061] like Fig.11 As shown, in the pre-forming process, the raised surface 13 of the intermediate formed product 11 is formed in a manner including the portion 15 that becomes the ridge line 4 in the subsequent flange forming process. In this specification, such a portion that becomes the ridge line 4 in the subsequent flange forming process is referred to as the "ridge line equivalent portion 15" as a portion equivalent to the ridge line 4. That is, the raised surface 13 of the intermediate formed product 11 is formed in a manner including the ridge line equivalent portion 15. In addition, the position of the ridge line equivalent portion 15 changes according to the product shape of the stamped product 1, the height of the flange 3, the shape of the intermediate product (the shape of the raised surface 13, etc.), etc. In addition, when forming the raised surface 13 including the ridge line equivalent portion 15, the range to which the blank 10 is raised is appropriately changed according to the product shape of the stamped product 1, the mold structure, etc. That is, the ratio of the first surface 12 of the intermediate formed product 11 to the raised surface 13 is appropriately changed according to the product shape of the stamped product 1, the mold structure, etc.

[0062] <Flange Forming Process>

[0063] like Figure 5As shown in (c), the stamped product 1 manufactured by the flange forming process has, as described above: a flat surface 2 (hereinafter referred to as the "second surface 2"); a flange 3 bent in a direction intersecting the second surface 2 (upward); and a ridge 4 (hereinafter referred to as the "second ridge 4") connecting the second surface 2 and the flange 3. When viewed from above along the stamping direction, the second ridge 4 extends in a convexly curved direction from the flange 3 toward the second surface 2. In addition, as described later, in the flange forming process, the first ridge 14 of the intermediate formed product 11 is pushed away and substantially disappears. However, the first ridge 14 may be flattened to become a trace of the first ridge, or the angle between the first surface 12 and the second surface 2 where the raised surface 13 is deformed becomes larger and the first ridge 14 remains. Figure 5 The first ridgeline trace (14) is shown in FIG. Even if the first ridgeline trace becomes flat, it can be identified by grinding the surface of the molded product with a file or measuring the hardness to investigate the work hardened part.

[0064] In the flange forming step of the present embodiment, for example, Figure 13 to Figure 15 The press forming device 40 of the structure shown in the figure forms the intermediate formed product 11 to manufacture the press formed product 1. Fig.13 Only the lower surface shape of the die 43 is shown. Fig.13 and Fig.14 Only the shape of the upper surface of the punch 41 is shown in FIG. The upper surface of the punch 41 and the lower surface of the die 43 are punching surfaces (forming portions) for forming the stamped product 1 from the intermediate formed product 11 .

[0065] like Fig.15 As shown, the stamping forming device 40 of the present embodiment includes a punch 41, a pad 42, and a die 43. The punch 41 has: a punch bottom surface portion 41a; a punch top surface portion 41b, which is located at a different height from the punch bottom surface portion 41a (above the punch bottom surface portion 41a in this embodiment); and a punch longitudinal wall surface 41c, which connects the punch bottom surface portion 41a and the punch top surface portion 41b. The punch bottom surface portion 41a and the punch top surface portion 41b of the punch 41 of the present embodiment are parallel to each other, but they may not be parallel. In addition, as Fig.13 As shown, a portion of the punch longitudinal wall surface 41c becomes a punch longitudinal wall portion 41c' having a curvature like the side surface of a cylinder. The punch longitudinal wall portion 41c', when viewed from above along the punching direction, becomes a curved shape that bulges in the direction from the punch top surface portion 41b toward the punch bottom surface portion 41a. That is, the surface of the punch longitudinal wall portion 41c' is convexly curved. In addition, a punch concave ridge line portion 41d is formed between the punch bottom surface portion 41a and the punch longitudinal wall portion 41c'. Similarly, the punch concave ridge line portion 41d, when viewed from above along the punching direction, becomes a curved shape that bulges in the direction from the punch top surface portion 41b toward the punch bottom surface portion 41a.

[0066] The pad 42 has a pad longitudinal wall surface 42a and a pad bottom surface 42b. The lower surface of the pad 42 is the pad bottom surface 42b. The pad longitudinal wall surface 42a is formed in a manner opposite to the die 43. A portion of the pad longitudinal wall surface 42a becomes a pad longitudinal wall portion 42a' having a curvature that is recessed from the die 43 toward the pad 42. The pad longitudinal wall portion 42a', when viewed from above along the punching direction, becomes a curved shape that protrudes from the pad longitudinal wall surface 42a toward the pad bottom surface 42b. In addition, a pad ridge portion 42c is provided between the pad bottom surface 42b and the pad longitudinal wall portion 42a'. Similarly, the pad ridge portion 42c, when viewed from above along the punching direction, becomes a curved shape that protrudes from the die 43 toward the pad 42. The backing plate vertical wall portion 42 a ′ is disposed adjacent to the die 43 , and the backing plate 42 is configured to be movable up and down at a position facing the punch bottom surface portion 41 a of the punch 41 .

[0067] The die 43 has a die bottom surface 43a, which is opposite to the punch bottom surface 41a; a die top surface 43b, which is opposite to the punch top surface 41b; and a die vertical wall surface 43c, which is opposite to the punch vertical wall surface 41c. The die 43 is configured to be able to rise and fall at a position between the punch vertical wall surface 41c and the backing plate 42. The die bottom surface 43a and the die top surface 43b of the die 43 of this embodiment are parallel to each other, but they may not be parallel. In addition, a part of the die vertical wall surface 43c is a die vertical wall portion 43c' with a curvature that is concave toward the inside of the die 43. The die vertical wall portion 43c' is a curved shape that is convex in the direction from the die top surface 43b toward the die bottom surface 43a when viewed from above along the punching direction. In addition, there is a die shoulder ridge line portion 43d between the die bottom surface 43a and the die vertical wall portion 43c'. Similarly, the die shoulder ridgeline portion 43d, when viewed from above along the punching direction, becomes a curved shape protruding from the die top surface portion 43b toward the die bottom surface portion 43a. In addition, the structure of the stamping forming device 40 is appropriately changed according to the product shape of the stamped product 1, and the processing method that can be adopted is also appropriately changed according to the product shape of the stamped product 1.

[0068] In the flange forming process using the press forming device 40, first, Fig.16 As shown in (a), the first surface 12 of the intermediate molded product 11 is pressed with a backing plate 42, and the die 43 is lowered in this state to press the raised surface 13 from the outer side of the bend of the raised surface 13 toward the inner side of the bend. Fig.16 As shown in FIG. 2( a ), the intermediate formed product 11 can be arranged between the upper surface of the punch 41 and the lower surface of the die 43 by sandwiching the first surface 12 of the intermediate formed product 11 between the pad bottom surface 42 b and the punch bottom surface 41 a .

[0069] As such, the intermediate formed product 11 is disposed between the upper surface of the punch 41 and the lower surface of the die 43. Fig.16 The die 43 is lowered as shown in (b). At the lower dead point of the forming process where the die 43 is lowered, the punch longitudinal wall portion 41c' is relatively adjacent to the die longitudinal wall portion 43c', the punch bottom surface portion 41a is relatively adjacent to the die bottom surface portion 43a, and the pad bottom surface portion 42b is relatively adjacent to the punch bottom surface portion 41a. In addition, at the lower dead point of the forming process where the die 43 is lowered in this way, when viewed from above along the punching direction, the die shoulder ridge line portion 43d extends in a convexly curved direction from the punch longitudinal wall portion 41c' toward the die longitudinal wall portion 43c', and the pad ridge line portion 42c extends in a convexly curved direction from the die 43 toward the pad 42.

[0070] The die 43 is lowered to the lower dead point of the forming process, so that the punch longitudinal wall portion 41c' of the punch 41 and the die longitudinal wall portion 43c' of the die 43 are used to press the intermediate formed product 11. Fig.16 As shown in (b), part of the raised surface 13 of the intermediate molded product 11 becomes a surface continuous with the first surface 12 of the intermediate molded product 11, as shown in FIG. Fig.17 The second surface 2 of the stamped product 1 is formed as shown. Along with this, the first ridgeline 14 of the intermediate product 11 may be pushed away and disappear. The ridgeline 14 of the die 1 may not be completely pushed away and remain. Even if the ridgeline of the die 1 disappears, traces of the ridgeline 14 of the die 1 may sometimes remain. In addition, in the remaining portion of the raised surface 13, the material flows into the gap between the punch longitudinal wall portion 41c' of the punch 41 and the die longitudinal wall portion 43c' of the die 43, as shown in FIG. Fig.17 As shown, the ridgeline equivalent portion 15 of the intermediate molded product 11 becomes the second ridgeline 4, and the top 13a of the raised surface 13 becomes the top 3a of the flange 3, thereby forming the flange 3. In the stamped product 1, the first ridgeline 4 exists continuously between the second surface 2 and the flange 3. When viewed from above along the stamping direction, the second ridgeline 4 extends in a curved shape that is convexly curved from the flange 3 toward the second surface 2. In addition, in the cross section along the stamping direction intersecting the second ridgeline 4, the second ridgeline 4 is directed obliquely downward (at Fig.17 That is, the direction in which the first ridge line 14 protrudes in the cross section of the intermediate molded product 11 in the punching direction intersecting the first ridge line 14 (in the Fig.11 Indicated by arrow e in the figure. ) and the direction in which the second ridge line 4 protrudes in the cross section of the stamping direction intersecting the second ridge line 4 in the stamping formed product 1 (in Fig.17 Indicated by arrow f. ) is the side of the same surface of the intermediate formed product 11 and the stamped formed product 1.

[0071] Since the second surface 2, the flange 3 and the second ridge 4 of the stamped product 1 are formed by the stamping forming device 40 in this way, Fig.18 As shown, the stamping forming device 40 has: a second surface forming portion 45, which is a portion of the second surface 2 of the stamped product 1; a flange forming portion 46, which is a portion of the flange 3 of the stamped product 1; and a second ridge line forming portion 47, which is a portion of the second ridge line 4 of the stamped product 1. The second surface forming portion 45 is formed between the punch bottom portion 41a of the punch 41 and the die bottom portion 43a of the die 43, the flange forming portion 46 is formed between the punch longitudinal wall portion 41c' of the punch 41 and the die longitudinal wall portion 43c' of the die 43, and the second ridge line forming portion 47 is formed between the punch concave ridge line portion 41d of the punch 41 and the die shoulder ridge line portion 43d of the die 43. In addition, as Figure 5 The second surface 2 in which a portion of the edge adjacent to the second ridgeline is bent and extended inwardly of the second surface 2 is formed by the second surface forming portion 45, so the second surface forming portion 45 has a portion of the edge that is bent inwardly of the second surface forming portion 45, and the flange forming portion 46 is provided at the bent portion of the second surface forming portion 45. The flange 3 of the stamped product 1 is formed by the flange forming portion 46, so the height H of the flange forming portion 46 is Fig.18 ) can be the same as the height H of the flange 3 ( Fig.17 ) are equal. In addition, as long as the height of the formed portion 46 is greater than the height of the flange 3, there will be no problem with the mold.

[0072] As described above, in the flange forming process using the press forming device 40, a portion of the raised surface 13 of the intermediate formed product 11 becomes a surface continuous with the first surface 12 of the intermediate formed product 11, as shown in FIG. Fig.17 The second surface 2 of the stamped product 1 is formed in this way. Along with this, the first ridgeline 14 of the intermediate product 11 is pushed away, and the first ridgeline 14 may also substantially disappear. However, the first ridgeline 14 of the intermediate product 11 does not need to be pushed away to a completely flat plate shape (180°) in the stamped product 1. When comparing the cross-sections in the stamping direction intersecting the first ridgeline 14 before and after the flange forming process, as long as Fig.17The angle (the angle between the second faces 2 adjacent to each other at the position corresponding to the first ridge line 14) (θ2) formed by the second face 2 at the position corresponding to the first ridge line 14 (the position corresponding to the first ridge line 14 existing in the intermediate formed product) in the stamped product 1 shown (after the flange forming process) is larger than the angle (θ1) formed by the raised face 13 adjacent to the first ridge line 14 and the first face 12 in the intermediate formed product 11 (before the flange forming process). In this way, the first ridge line 14 existing in the intermediate formed product can also become a part of the second face 2 in the stamped product 1 by being pushed away in the flange forming process. In addition, the first ridge line 14 between the first face 12 and the second face can maintain the shape of the extension direction of the ridge line, or it can become a trace of the first ridge line 14.

[0073] The press-formed product 1 having an extended flange portion of the present embodiment is manufactured through the above steps. In the press-formed product 1 manufactured in this way, the tensile strain generated at the tip of the flange 3 is small. The reason for this is described below.

[0074] Fig.19 1 is a diagram of the intermediate formed product 11 after the preforming process as viewed from the stamping direction (viewed from above). Fig.19 In the figure, the shape of the blank 10 and the stamped product 1 after the flange forming step can be compared. Fig.19 The figure shows the positional relationship between the first surface 12, raised surface 13 and first ridge 14 appearing on the intermediate formed product 11 and the second surface 2, flange 3 and second ridge 4 appearing on the stamped product 1 when the position of the blank 10 is fixed and the intermediate formed product 11 and the stamped formed product 1 are processed in sequence from the same blank 10. The notch 10a of the blank 10 and the second ridge 4 of the stamped product 1 are indicated by double-dashed lines. In addition, in the stamped product 1 of the present embodiment, Fig.17 In the case where the flange 3 is a shape extending in a direction perpendicular to the second surface 2, Fig.19 In such a plan view, the position of the flange 3 and the position of the second ridgeline 4 are substantially the same position.

[0075] In addition Fig.19 In order to compare the curvatures of the first edge line 14 appearing in the intermediate formed product 11 and the second edge line 4 appearing in the stamped formed product 1 in the extending direction, a straight line L intersecting the first edge line 14 of the intermediate formed product 11 and orthogonal to the second edge line 4 of the stamped formed product 1 is shown. The curvature radius R1 of the extending direction of the first edge line 14 at the intersection point 14a of the straight line L and the first edge line 14 and the curvature radius R2 of the extending direction of the second edge line 4 at the intersection point 4a of the straight line L and the second edge line 4 are compared.

[0076] like Fig.19As shown, when the radius of curvature of the notch 10a at the intersection of the straight line L and the notch 10a of the blank 10 in a plan view is set to R, and the height of the flange 3 after the flange is formed is set to H, the circumferential strain ε1 generated at the top end of the flange 3 when the flange 3 is formed from the blank 10 in one process is expressed by the following formula, for example. In addition, "one process" refers to a process in which the blank 10 is stamped to form the stamped product 1.

[0077] ε1={(R+H)×π×(1 / 4)-R×π×(1 / 4)} / {R×π×(1 / 4)}=H / R

[0078] On the other hand, when the stamped product 1 is formed from the blank 10 through the preforming process, in the preforming process, the curvature radius R+K of the top 13a of the raised surface of the intermediate formed product 11 when viewed from above is larger than the curvature radius R of the notch 10a of the blank 10 when viewed from above. In this case, the circumferential strain ε2 generated at the top of the flange 3 when the flange 3 is formed from the intermediate formed product 11 as in the present embodiment is expressed by the following formula. In addition, "K" in the following formula is the difference between the curvature radius of the top 13a of the raised surface 13 and the curvature radius of the notch 10a of the blank 10.

[0079] ε2={(R+H)×π×(1 / 4)-(R+K)×π×(1 / 4)} / {(R+K)×π×(1 / 4)}=(HK) / R+K

[0080] When comparing the above-mentioned ε1 and ε2, the value of the numerator of ε2 is smaller than the value of the numerator of ε1 by the amount of K, and the value of the denominator of ε2 is larger than the value of the denominator of ε1 by the amount of K. That is, since ε2 is smaller than ε1, when the flange 3 is formed by a pre-forming process such as the present embodiment, the strain generated at the top end of the flange 3 is smaller. In addition, in the process of forming the flange 3 from the raised surface 13 through the flange forming process, the circumferential line length around the second ridge line 4 of the stamped product 1 becomes shorter. Therefore, there is excess material around the second ridge line 4 of the stamped product 1, so that the material tends to flow toward the top end side of the flange 3 in the flange forming process. The tensile strain at the top end of the flange 3 is thereby suppressed.

[0081] Therefore, according to the manufacturing method of performing the preforming process of forming the raised surface 13 as in the present embodiment, it is possible to manufacture a stamped product 1 having an extended flange portion while suppressing the tensile strain of the top end portion of the flange 3. As a result, the forming difficulty of the stamped product 1 having the extended flange portion can be reduced, and the component can be formed into a desired shape even if the material of the component is made of a higher strength material.

[0082] In order to obtain the tensile strain suppression effect of the top end of the flange 3 as described above, it is necessary to perform stamping in such a manner that the radius of curvature R1 of the first ridge 14 of the intermediate formed product 11 when viewed from above (the radius of curvature R1 of the first ridge 14 in the extension direction at the intersection 14a of the first ridge 14 of the intermediate formed product 11 and the straight line L) is larger than the radius of curvature R2 of the second ridge 4 in the stamped product 1 when viewed from above (the radius of curvature R2 of the extension direction of the second ridge 4 at the intersection 4a of the second ridge 4 in the stamped product 1 after the flange forming process) is larger. By performing such stamping, the radius of curvature R+K of the top end 13a of the raised surface when viewed from above is larger than the radius of curvature R of the notch 10a of the blank 10 when viewed from above, and the raised surface 13 includes a ridge equivalent portion 15. In order to obtain the aforementioned effect of suppressing the tensile strain at the top end of the flange 3, for the stamping production line 20, when observed along the stamping direction, the curvature radius R1 of the first edge forming portion 37 of the pre-forming device 30 needs to be larger than the curvature radius R2 of the second edge forming portion 47 of the stamping device 40.

[0083] Fig. 20 3 is a top view schematically showing the first surface forming section 35, the raised surface forming section 36 and the first ridge forming section 37 of the preforming device 30. Fig. 20 In the figure, the second surface forming portion 45, the flange forming portion 46 and the second ridge forming portion 47 of the stamping device 40 are indicated by double dotted lines at corresponding positions. Here, the corresponding positions refer to the positional relationship between the punch 31, the pad 32 and the die 33 of the pre-forming device 30 for stamping the intermediate formed product 11 and the positional relationship between the punch 41, the pad 42 and the die 43 of the stamping device 40 for further stamping the intermediate formed product 11 into the stamped formed product 1 when the intermediate formed product 11 stamped by the pre-forming device 30 is further stamped by the stamping device 40 to manufacture the stamped formed product 1. In the stamping device 40 of the present embodiment, when the flange 3 formed by the flange forming portion 46 is a shape extending in a direction perpendicular to the second surface 2, in the figure Fig. 20 In such a plan view, the flange forming portion 46 and the second ridge forming portion 47 are located at substantially the same position.

[0084] The first ridgeline forming portion 37 is formed between the concave ridgeline portion 31d of the preliminary forming punch 31 and the preliminary forming die shoulder ridgeline portion 33c of the preliminary forming die 33. The second ridgeline forming portion 47 is formed between the punch concave ridgeline portion 41d of the punch 41 and the die shoulder ridgeline portion 43d of the die 43.

[0085] In addition Fig. 20In order to compare the curvature radius of the first ridge forming portion 37 (the concave ridge line portion 31d of the preforming punch 31 and the preforming die shoulder ridge line portion 33c of the preforming die 33) and the second ridge forming portion 47 (the punch concave ridge line portion 41d of the punch 41 and the die shoulder ridge line portion 43d of the die 43) in the extending direction, Fig.19 Similarly, a common straight line L' is shown which intersects the preforming die shoulder ridge line 33c (concave ridge line 31d) and is orthogonal to the die shoulder ridge line 43d (punch concave ridge line 41d). The curvature radius R1' of the preforming die shoulder ridge line 33c (concave ridge line 31d) in the extending direction at the intersection point 37a of the straight line L' and the preforming die shoulder ridge line 33c (concave ridge line 31d) and the curvature radius R2' of the die shoulder ridge line 43d (punch concave ridge line 41d) in the extending direction at the intersection point 47a of the straight line L' and the die shoulder ridge line 43d (punch concave ridge line 41d) are compared.

[0086] Here, the second ridge forming portion 47 is a portion of the second ridge 4 of the stamped product 1, and the radius of curvature R2' of the extension direction of the die shoulder ridge portion 43d (punch concave ridge portion 41d) must be consistent with the radius of curvature R2 of the second ridge 4 of the stamped product 1 when viewed from the stamping direction during stamping. In addition, the first ridge forming portion 37 is a portion of the first ridge 14 of the intermediate product 11, and the radius of curvature R1' of the extension direction of the pre-forming die shoulder ridge portion 33c (concave ridge portion 31d) must be consistent with the radius of curvature R1 of the first ridge 14 of the intermediate product 11 when viewed from above. Therefore, similarly to the above, in order to obtain the effect of suppressing the tensile strain at the top end of the flange 3, it is necessary to make the curvature radius R1' of the pre-forming die shoulder ridge line portion 33c (concave ridge line portion 31d) in the extension direction larger than the curvature radius R2' of the die shoulder ridge line portion 43d (punch concave ridge line portion 41d) in the extension direction.

[0087] Furthermore, in the flange forming step, in the press forming device 40, as shown in FIG. Fig.16 As shown in (a), the first surface 12 of the intermediate formed product 11 is pressed by the pad 42, and the die 43 is lowered in this state to press the raised surface 13 from the outer side of the bend of the raised surface 13 toward the inner side of the bend. In this case, it is desired to constrain the intermediate formed product 11 stably. Therefore, it is sufficient to make the pad bottom surface 42b of the pad 42 close to the position of the first surface 12 of the intermediate formed product 11 as close to the first ridge line 14 as possible. In a state where the pad bottom surface 42b of the pad 42 is constrained to the position of the first surface 12 of the intermediate formed product 11 as close to the first ridge line 14 as possible, by lowering the die 43, the stamped product 1 can be stamped with higher processing accuracy.

[0088] In order to use the pad bottom surface 42b of the pad 42 to press the first surface 12 of the intermediate formed product 11 to a position as close to the first edge line 14 as possible, the radius of curvature of the pad edge line 42c, which is formed into a curved shape protruding in the direction from the die 43 toward the pad 42 when viewed from above along the stamping direction, may be the same as the radius of curvature R1 of the first edge line 14 of the intermediate formed product 11 when viewed from above. By setting the radius of curvature of the pad edge line 42c when viewed from above in the stamping direction to R1, the pad bottom surface 42b of the pad 42 can be used to constrain the first surface 12 of the intermediate formed product 11 to a position closest to the first edge line 14 for stamping, thereby manufacturing a stamped product 1 without wrinkles. When the radius of curvature of the pad edge line 42c when viewed from above is R1, Fig. 20 Similarly, on the straight line intersecting the pad edge 42c and the die shoulder edge 43d, the curvature radius of the extension direction of the pad edge 42c at the intersection of the pad edge 42c and the straight line must be larger than the curvature radius of the extension direction of the die shoulder edge 43d at the intersection of the die shoulder edge 43d and the straight line.

[0089] In addition, the curvature radius of the backing plate ridgeline portion 42c in the extending direction may be made larger than R1, and when the die 43 is lowered, the first ridgeline 14 of the intermediate molded product 11 is flattened by the die bottom surface portion 43a of the die 43. In this case, the curvature radius of the backing plate ridgeline portion 42c in the extending direction is maintained larger than the curvature radius of the die shoulder ridgeline portion 43d in the extending direction on the straight line orthogonal to the die shoulder ridgeline portion.

[0090] In addition, the preforming device 30 and the stamping forming device 40 are independent devices, and the intermediate formed product may not be transported between the devices without changing its direction. Therefore, the positional relationship between the first surface 12, the raised surface 13 and the first ridge 14 appearing in the intermediate formed product 11 and the second surface 2, the flange 3 and the second ridge 4 appearing in the stamped formed product 1 is offset. If this situation is taken into consideration, it can also be set to a relationship in which the average value of the radius of curvature in the extension direction of the pad ridge portion 42c is greater than the average value of the radius of curvature in the extension direction of the die shoulder ridge portion 43d. For example, when viewed from above along the stamping direction, the radius of curvature of the pad ridge portion 42c formed into a curved shape protruding from the die 43 toward the pad 42 can be measured at equal intervals at multiple locations (for example, 10 locations), and the average value of the 8 measured values ​​excluding the highest and lowest values ​​is used as the radius of curvature of the pad ridge portion 42c. Similarly, when viewed from above in the punching direction, the radius of curvature of the die shoulder ridgeline portion 43d formed in a curved shape protruding from the die top surface portion 43b toward the die bottom surface portion 43a can be measured at multiple locations (e.g., 10 locations) at equal intervals, and the average value of the 8 measured values ​​excluding the highest and lowest values ​​is taken as the radius of curvature of the die shoulder ridgeline portion 43d. It is sufficient that the average value of the radius of curvature of the pad ridgeline portion 42c measured in this way is greater than the average value of the radius of curvature of the die shoulder ridgeline portion 43d.

[0091] In addition, the height h ( Fig.12 ) is preferably the height H of the flange forming portion 46 of the stamping forming device 40 ( Fig.18 In other words, it is preferred that the height h of the raised surface 13 of the intermediate molded product 11 be greater than Fig.11 ) is the height H of the flange 3 of the stamped product 1 ( Fig.17 ) or more. Thus, when the intermediate formed product 11 is placed in the stamping forming device 40, the first surface 12 near the raised surface 13 is not easy to float up, and the forming can be performed in a more stable posture. The "height h of the raised surface forming portion 36" in this specification refers to the length of the raised surface forming portion 36 of the preforming device 30 from the position of the second ridge forming portion 47 corresponding to the stamping forming device 40 to the direction perpendicular to the first surface forming portion 35. In addition, in the preforming device 30 and the stamping forming device 40, the positions for placing the formed product (blank 10 or intermediate formed product 11) are respectively predetermined, so the position of the second ridge forming portion 47 in the preforming device 30 corresponding to the stamping forming device 40 is uniquely determined based on the comparison of the placement positions of the formed products in the preforming device 30 and the stamping forming device 40.

[0092] The length L1 ( Fig.12 ) is preferably a length L2 ( Fig.18 ). In other words, it is preferred that the stamping is performed in such a manner that the length from the first ridgeline 14 of the intermediate formed product 11 to the top 13a of the raised surface 13 is 1.00 to 1.05 times the length from the position corresponding to the first ridgeline 14 of the intermediate formed product 11 to the top 3a of the flange 3. This makes it easy to suppress the formation of wrinkles at the root of the flange 3. From the viewpoint of improving the wrinkle suppression effect at the root of the flange 3, the length L1 is more preferably less than 1.04 times the length L2, and further preferably less than 1.03 times. In addition, since the positions for placing the to-be-formed products (blank 10 or intermediate formed products 11) are predetermined in the pre-forming device 30 and the stamping device 40, respectively, the position of the top end 36a of the raised surface forming portion 36 in the pre-forming device 30 and the position of the first edge forming portion 37 in the stamping device 40 corresponding to the pre-forming device 30 are uniquely determined based on the comparison of the placement positions of the to-be-formed products in the pre-forming device 30 and the stamping device 40.

[0093] In addition, if Fig.12 , Fig.13 as well as Fig. 20 As shown, the curvature radius R3 at the position 36b of the ridgeline equivalent portion 15 of the formed intermediate formed product 11 of the raised surface forming portion 36 of the pre-forming device 30 when viewed from the stamping direction is preferably 1.29 times or less of the curvature radius R2 of the second ridgeline forming portion 47 of the stamping forming device 40 when viewed from the top. In other words, it is preferred to perform stamping in a manner in which the curvature radius of the ridgeline equivalent portion 15 of the intermediate formed product 11 when viewed from the top is 1.29 times or less of the curvature radius of the second ridgeline 4 of the stamped product 1 when viewed from the top. This can reduce the wrinkles that may occur at the root of the flange 3. From the viewpoint of improving the wrinkle suppression effect at the root of the flange 3, the curvature radius R3 is more preferably 1.28 times or less of the curvature radius R2. In addition, the preferred lower limit of the ratio of R3 to R2 will also vary depending on the product shape of the stamped product 1, so it is not particularly limited, but the curvature radius R3 is, for example, set to be more than 1.00 times the curvature radius R2. In addition, since the positions for placing the formed products (blank 10 or intermediate formed product 11) are predetermined in the pre-forming device 30 and the stamping device 40 respectively, the position 36b of the ridge line equivalent portion 15 of the formed intermediate formed product 11 of the raised surface forming portion 36 of the pre-forming device 30 is uniquely determined based on the comparison of the placement positions of the formed products of the pre-forming device 30 and the stamping device 40.

[0094] In addition, if Fig.11As shown, in the illustrated manner, an example is shown in which the raised surface 13 of the intermediate formed product 11 is substantially straight from the first ridge 14 to the ridge equivalent portion 15 in a cross section along the stamping direction intersecting the first ridge 14. However, as shown in the embodiment described later, in this cross section, the raised surface 13 of the intermediate formed product 11 may be formed in a manner that is a curve that bulges toward the pre-forming punch 31 (bulges toward the stamping direction). That is, a curved surface bulging toward the pre-forming punch 31 may be formed on the raised surface 13. In other words, the raised surface 13 may also have a curved surface that becomes steeper as it moves away from the first surface. In addition, in this cross section, when the raised surface 13 of the intermediate formed product 11 is a curved surface bulging toward the pre-forming die 33, it is possible that deflection occurs on the second surface 2 of the stamped product 1 during the flange forming process.

[0095] An example of an embodiment of the present invention is described above, but the present invention is not limited to this example. It is clear that anyone skilled in the art can think of various variations or modifications within the scope of the technical ideas described in the claims, and it should be understood that these also belong to the protection scope of the present invention.

[0096] For example, in the above-mentioned embodiment, the curved notch 10a is provided as the initial shape of the blank 10, but even in the case of Fig.21 Even when the blank 10 is not provided with the notch 10a as in (a), the flange 3 can be formed while suppressing tensile strain. Fig.21 In the embodiment, a trimming step is provided between the preforming step and the flange forming step. The method for manufacturing the press-formed product 1 is as follows.

[0097] First, the preforming step is performed in the same manner as in the above embodiment. Fig.21 The first intermediate molded product 11a is manufactured by forming a raised surface 13 as shown in (b). Fig.21 As shown in (c), in order to obtain a flange 3 of a predetermined height in the subsequent flange forming step, the top end of the raised surface 13 is cut based on the product height of the flange 3 to produce a second intermediate formed product 11b. Finally, in the same manner as in the above embodiment, the flange forming step is performed to form a flange 3 from the second intermediate formed product 11b. Fig.21 The stamped product 1 having an extended flange portion is manufactured by forming a flange 3 as shown in (d). The stamped product 1 manufactured by such a method also suppresses the strain at the top end of the flange 3. Therefore, the method for manufacturing the stamped product 1 having an extended flange portion is not limited to the method described in the above embodiment. Fig. 22As shown, in order to perform the above-mentioned trimming process, a cutting machine 50 for cutting the top end portion of the raised surface 13 of the intermediate formed product 11 is provided between the preforming device 30 and the press forming device 40 of the press forming line 20, for example. The structure of the cutting machine 50 is not particularly limited as long as it can cut the top end portion of the raised surface 13, but for example, it can be configured in a manner that the top end portion of the raised surface 13 is cut using a third press die (not shown).

[0098] In addition, in this embodiment, Figure 5 The intermediate molded product 11 shown in (b) Figure 5 The present invention is also applicable to the following cases: in the preforming process, the intermediate formed product is formed into Figure 5 The shape of the stamped product 1 shown in (c) is along Figure 4 The dotted line X shown in FIG. is bent to form Figure 3 The joint 82 shown has a first flange 82a and a second flange 82b continuously connected.

[0099] Example

[0100] <Simulation (1)>

[0101] A forming simulation of a component with an extended flange was performed. In this simulation, a hot-dip galvanized steel sheet with a yield point of 510 MPa, a tensile strength of 821 MPa, and an elongation of 22% was used as the blank, and a flange with a top curvature radius of 15 mm and a height of 10 mm accompanied by extended flange deformation was formed as a condition. PAM-STAMP was used as the analysis solver, and the mesh size of the blank was 1 mm × 1 mm.

[0102] In this simulation, flanges are formed using respective methods of a conventional forming method (Comparative Example 1) and a forming method of an example of the present invention (Example 1, Example 2). The forming method of Comparative Example 1 is a method of forming a flange from a blank having a curved notch portion through a single process. The forming method of Example 1 is a method of, for the same blank as that of Comparative Example 1, forming an intermediate formed product having a raised surface through a pre-forming process, and forming a flange from the intermediate formed product through a flange forming process. The forming method of Example 2 is a method of, for a blank having no notch portion, forming a first intermediate formed product having a raised surface through a pre-forming process, forming a second intermediate formed product by cutting the top end of the raised surface through a trimming process, and forming a flange from the second intermediate formed product through a flange forming process. In the pre-forming process of the example, the radius of curvature R1 ( Fig.19) is formed into an intermediate molded product 11 in a manner that the curvature radius R2 is larger than the second ridgeline 4. The shape of the component in each process in each example of the embodiment and the comparative example is shown in Table 1 below.

[0103] [Table 1]

[0104]

[0105] Figure 23 to Figure 25 is a diagram showing the distribution of the change in the plate thickness of the component after flange forming relative to the plate thickness of the blank. Fig.23 The results of Comparative Example 1 are shown. Fig.24 The results of Example 1 are shown. Fig.25 The results of Example 2 are shown. Fig.23 As shown in FIG. 1 , it can be seen that the plate thickness reduction rate of the top end portion of the flange is large in Comparative Example 1, and a large extension flange deformation occurs at the top end portion. Fig.24 and Fig.25 As shown, it can be seen that in Examples 1 and 2, the plate thickness reduction rate of the tip portion of the flange is smaller than that of Comparative Example 1, and the stretch flange deformation is suppressed.

[0106] Fig.26 is a graph showing the magnitude of the circumferential strain at a horizontal position from the flange. Fig.26 On the vertical axis, positive values ​​represent tensile strain and negative values ​​represent compressive strain. Fig.26 As shown in the results, in Example 1 and Example 2, the tensile strain of the flange is suppressed compared with Comparative Example 1.

[0107] <Simulation (2)>

[0108] use Fig.12 The length L1 of the pre-forming device 30 shown is Fig.18 The forming simulation was performed using a plurality of analysis models with different ratios (L1 / L2) of the length L2 in the press forming device 40. The simulation conditions such as the material of the blank, the final shape, and the analysis solver were the same as those in the above-mentioned simulation (1).

[0109] exist Fig. 27 The simulation results are shown in . In this simulation, the plate thickness increase rate at the root of the flange is used as an evaluation index, and the presence or absence of wrinkles at the root of the flange is estimated from the plate thickness increase rate. When the plate thickness increase rate at the root of the flange relative to the plate thickness of the blank exceeds 15%, there is too much material near the root of the flange during the forming of the flange, and wrinkles may sometimes occur at the root of the flange. Fig. 27As shown, when L1 / L2 is less than 1.05, the plate thickness increase rate is less than 15%, and the wrinkles at the root of the flange can be suppressed. In addition, in any analysis model, the plate thickness reduction rate at the top of the flange is smaller than the plate thickness reduction rate of Comparative Example 1 of Simulation (1). Therefore, by performing the press forming of the present invention under the condition that L1 / L2 is less than 1.05, the tensile strain at the top of the flange can be suppressed, and the wrinkles at the root of the flange can be suppressed.

[0110] <Simulation (3)>

[0111] use Fig. 20 The forming simulation is performed using multiple analysis models with different ratios (R3 / R2) of the curvature radius R3 of the preforming device 30 and the curvature radius R2 of the stamping forming device 40. In addition, the simulation conditions such as the raw material of the blank, the final shape, and the analysis solver are the same as those of the above-mentioned simulation (1).

[0112] exist Fig.28 The simulation results are shown in Figure 2. In this simulation, the plate thickness increase rate at the flange root is used as an evaluation index, and the presence or absence of wrinkles at the flange root is estimated from the plate thickness increase rate. Fig.28 As shown, when R3 / R2 is less than 1.29, the plate thickness increase rate becomes less than 15%, and the wrinkles at the root of the flange can be suppressed. In addition, in any analysis model, the plate thickness reduction rate at the top end of the flange is smaller than the plate thickness reduction rate of Comparative Example 1 of Simulation (1). Therefore, by performing the stamping of the present invention under the condition that R3 / R2 is less than 1.29, the tensile strain at the top end of the flange can be suppressed, and the wrinkles at the root of the flange can be suppressed. In addition, by performing the stamping of the present invention under the conditions that L1 / L2 is less than 1.05 and R3 / R2 is less than 1.29, the effect is further improved.

[0113] <Simulation (4)>

[0114] like Fig.29 As shown, in the case where the raised surface 13 of the intermediate formed product 11 is formed into a curve convex toward the preforming punch 31 (convex toward the bottom) ( Fig.29 (a)) and the raised surface 13 of the intermediate molded product 11 is formed as a curve that bulges toward the preforming die 33 (bulges upward) ( Fig.29 The forming simulation was carried out to investigate the influence of (a)) on the second surface of the stamped product. Fig.29 As shown in (a), when the raised surface 13 is formed in a curved shape that bulges toward the preforming punch 31 (bulges downward), the raised surface 13 can be press-formed without generating wrinkles in the flange forming step. Fig.29As shown in (b), when the raised surface 13 is formed in a curved shape that bulges toward the preforming die 33 (bulges upward), wrinkles may be generated on the second surface 2 during the flange forming process. The raised surface 13 of the intermediate molded product 11 is preferably a substantially straight line from the first ridgeline 14 to the ridgeline equivalent portion 15 or a curved surface that bulges toward the punching direction.

[0115] Industrial Applicability

[0116] The present invention can be applied to the production of a press-formed product having an extended flange portion.

[0117] Description of Reference Numerals

[0118] 1. stamping product with extended flange; 2. surface (second surface); 3. flange; 3a. top of flange; 4. ridge (second ridge); 10. blank; 10a. notch; 11. intermediate formed product; 11a. first intermediate formed product; 11b. second intermediate formed product; 12. first surface; 13. raised surface; 13a. top of raised surface; 14. first ridge; 15. ridge equivalent portion; 20. stamping production line; 30. preforming device; 31. preforming punch; 31a. bottom portion of preforming punch; 31b , pre-forming punch top face; 31c, pre-forming punch inclined face; 31c', pre-forming punch longitudinal wall; 31d, concave ridge line; 32, pre-forming pad; 33, pre-forming die; 33a, pre-forming die top face; 33b, pre-forming die inclined face; 33b', pre-forming die longitudinal wall; 35, first surface forming part; 36, raised surface forming part; 36a, top of raised surface forming part; 36b, position of the ridge line equivalent part of the intermediate formed product of the raised surface forming part; 37, first ridge line forming part; 40, stamping forming device; 4 1. Punch; 41a, punch bottom face; 41b, punch top face; 41c, punch vertical wall; 41c', punch vertical wall; 41d, punch concave ridge; 42, pad; 42a, pad vertical wall; 42a', pad vertical wall; 42b, pad bottom face; 42c, pad ridge; 43, die; 43a, die bottom face; 43b, die top face; 43c, die vertical wall; 43c', die vertical wall; 45, second surface forming portion; 46, flange forming portion; 46a, top end of flange forming portion; 47 , the second ridge forming part; 50, a cutting machine; 80, the first component; 81, the second component; 82, a joint; 82a, the first flange; 82b, the second flange; 82c, the third flange; H, the height of the flange forming part; h, the height of the raised surface forming part; K, the difference between the radius of curvature of the top of the raised surface and the radius of curvature of the second ridge; R, the radius of curvature of the notch; R1, the radius of curvature of the first ridge forming part; R2, the radius of curvature of the second ridge forming part; R3, the radius of curvature of the position of the ridge equivalent portion of the intermediate formed product of the raised surface forming part.

Claims

1. A method for manufacturing a stamped product, wherein: The manufacturing method of the stamped product comprises the following flange forming step: constraining the first surface of an intermediate formed product having a first surface, a raised surface, and a first ridgeline located between the first surface and the raised surface, and stamping the raised surface into a second surface, a flange, and a second ridgeline located between the second surface and the flange, wherein the raised surface is a surface raised upward relative to the first surface, When viewed from the stamping direction of the stamping forming, the first ridgeline extends in a convexly curved direction from the raised surface toward the first surface, and the second ridgeline extends in a convexly curved direction from the flange toward the second surface. The convex direction of the first ridgeline in the cross section along the punching direction intersecting the first ridgeline and the convex direction of the second ridgeline in the cross section along the punching direction intersecting the second ridgeline are on the same side, The curvature radius of the first ridgeline of the intermediate formed product at the intersection of the first ridgeline and the straight line orthogonal to the second ridgeline in the extending direction is larger than the curvature radius of the second ridgeline on the straight line after the flange forming step. Compared to an angle formed by the raised surface adjacent to the first ridgeline in the intermediate molded product and the first surface, an angle formed by the second surface at a position corresponding to the first ridgeline after the flange forming step is larger.

2. The method for manufacturing a press-formed product according to claim 1, wherein: The length of the intermediate molded product from the first ridgeline to the top end of the raised surface is 1.00 to 1.05 times the length from a position corresponding to the first ridgeline to the top end of the flange after the flange forming step.

3. The method for manufacturing a press-formed product according to claim 1 or 2, wherein: The height of the raised surface of the intermediate molded product is greater than or equal to the height of the flange after the flange forming step.

4. The method for producing a press-formed product according to claim 1 or 2, wherein: The radius of curvature in the extending direction of the ridgeline corresponding portion of the intermediate molded product, which is the portion to be the second ridgeline, is 1.29 times or less of the radius of curvature in the extending direction of the second ridgeline after the flange forming step.

5. The method for producing a press-formed product according to claim 1 or 2, wherein: In a cross section along a punching direction intersecting the first ridgeline, the raised surface of the intermediate molded product is formed as a curved line that is convex toward the punching direction.

6. The method for manufacturing a press-formed product according to claim 1 or 2, wherein: This method for producing a press-formed product includes a preforming step of forming the intermediate formed product.

7. The method for manufacturing a press-formed product according to claim 6, wherein: The method for manufacturing a press-formed product comprises a finishing step after the preforming step. In the trimming step, the tip end portion of the raised surface is cut according to the height of the flange formed in the flange forming step.

8. A stamping forming device, wherein: The stamping forming device comprises a punch, a die and a backing plate. The punch includes a punch vertical wall portion, a punch bottom portion, and a concave ridge line portion located between the punch vertical wall portion and the punch bottom portion. The die comprises a die vertical wall portion, a die bottom portion, and a die shoulder ridge portion located between the die vertical wall portion and the die bottom portion. The pad includes a pad vertical wall portion, a pad bottom portion, and a pad ridge portion located between the pad vertical wall portion and the pad bottom portion. When viewed in the punching direction, the backing plate ridgeline portion is curved and extends convexly in a direction from the punching die toward the backing plate. When viewed in the punching direction, the die shoulder ridgeline portion extends in a convexly curved manner in a direction from the punch longitudinal wall portion toward the die longitudinal wall portion. The backing plate longitudinal wall portion is arranged adjacent to the punch die, At the forming bottom dead point, the punch longitudinal wall portion is relatively adjacent to the die longitudinal wall portion. At the bottom dead point of forming, the punch bottom surface portion is adjacent to the die bottom surface portion. At the bottom dead point of forming, the bottom surface of the pad is adjacent to the bottom surface of the punch. The curvature radius of the extending direction of the backing plate ridgeline portion at the intersection of the backing plate ridgeline portion on a straight line orthogonal to the die shoulder ridgeline portion and the straight line is larger than the curvature radius of the extending direction of the die shoulder ridgeline portion on the straight line.

9. A stamping production line, wherein: The press forming production line comprises a pre-forming device and the press forming device according to claim 8, The preforming device comprises a preforming punch and a preforming die, The preforming punch comprises a preforming punch vertical wall portion, a preforming punch bottom portion, and a preforming punch concave ridge line portion located between the preforming punch vertical wall portion and the preforming punch bottom portion. The preforming die comprises a preforming die vertical wall portion, a preforming die bottom portion, and a preforming die shoulder ridge portion located between the preforming die vertical wall portion and the preforming die bottom portion. When viewed in the punching direction, the preforming die shoulder ridgeline portion is curved and extends convexly in a direction from the preforming punch longitudinal wall portion toward the preforming die longitudinal wall portion. At the forming bottom dead point, the preforming punch longitudinal wall portion is relatively adjacent to the preforming die longitudinal wall portion. At the forming bottom dead point, the preforming punch bottom surface portion is adjacent to the preforming die bottom surface portion. The radius of curvature of the extension direction of the preforming die shoulder ridgeline at the intersection of the preforming die shoulder ridgeline and a straight line that is orthogonal to the die shoulder ridgeline of the press forming device and intersects the preforming die shoulder ridgeline of the preforming device is larger than the radius of curvature of the extension direction of the die shoulder ridgeline on the straight line. In the cross section along the stamping direction intersecting the preforming die shoulder ridge of the preforming die of the preforming device and the pad ridge of the pad of the stamping device, the angle formed by the die bottom face portion adjacent to the pad ridge portion and the pad bottom face portion is larger than the angle formed by the preforming die longitudinal wall portion adjacent to the preforming die shoulder ridge portion and the preforming die bottom face portion.

Images