Method for manufacturing a stamped part, metal sheet for stamping and high tensile steel sheet

Abstract

A press-formed part having a shape with one or more than two curved portions in which a top plate portion is convexly or concavely curved when viewed from the side is suppressed from generating wrinkles with a simple means. A press part manufacturing method in which a metal plate (4) is formed into a press part shape (1) having a cross section with a top plate portion (1A) and a side wall portion (1B) continuous with at least one of the width directions of the top plate portion (1A) via a first curved portion (1d), and having one or more than two curved portions (10) in which the top plate portion (1A) is convexly or concavely curved when viewed from the side in a direction intersecting the cross section, i.e., a length direction, includes: a first preliminary forming step having a step of forming a first reinforcing rib (4a) extending in the length direction on the metal plate (4) at a position that becomes the first curved portion (1d); and a first part forming step of forming the metal plate (4) after the first preliminary forming step into the press part shape (1).

Description

Technical Field

[0001] The present invention relates to the manufacturing technology of stamped parts, wherein the stamped part has a shape having at least a top plate portion and a side wall portion that is continuous with at least one of the top plate portion in the width direction, such as a "コ"-shaped cross section, a hat-shaped cross section, or an "L"-shaped cross section, and has a curved portion along the length direction intersecting the above cross section, such that when viewed from the side, the top plate portion is bent in a manner that bulges or recesses in the thickness direction of the top plate portion. Background Technology

[0002] In industries such as automobiles and home appliances, many stamped parts are manufactured by deforming flat metal sheets into various shapes. In mass production of stamped parts, the manufacturing process widely employs stamping (stamping processing), which uses presses and dies to deform metal sheets. Typically, because the metal sheet is flat before processing, it must be able to stretch and contract to match the shape in order to deform it into a complex three-dimensional form. However, the more complex the shape of the stamped part, the more difficult it becomes to impart stretch and contraction to the metal sheet to match the three-dimensional shape. This difficulty is particularly pronounced when the stamped metal sheet is made of high-tensile steel or aluminum alloy with a tensile strength of 590 MPa or higher, and when the metal sheet is used for difficult-to-form parts with poor ductility and Rankeford values.

[0003] In stamping, if the sheet metal cannot be given the stretch and contraction required to match the three-dimensional shape, forming defects such as cracking and wrinkling can occur. Specifically, when the sheet metal is deformed into a three-dimensional shape, in areas where the sheet metal is too short and the excess cannot be compensated for from the surrounding area, the sheet metal must stretch. If the sheet metal is stretched beyond its own ductility, cracking occurs. On the other hand, when the sheet metal must be shortened during deformation into a three-dimensional shape, there is a tendency for wrinkling to occur in areas where excess material flows in from the surrounding area.

[0004] As an example of a part shape that is difficult to stamp, there is a stamped part whose cross-section includes a top plate portion, a longitudinal wall portion continuous with the top plate portion, and a flange portion continuously formed with the longitudinal wall portion, and the stamped part has one or more curved shapes when viewed from the side along the length direction.

[0005] When stamping such complex parts from flat metal sheets, the stamped parts are prone to cracking and wrinkling because the metal sheet undergoes tensile and compressive deformation during the forming process.

[0006] Here, in the case of stamping a product with the above-described complex shape from a metal plate, for example, bending using a die formed by a punch, a die, and a gasket, and deep drawing using a die formed by a punch, a die, and a blank holder (wrinkle-preventing press plate) are performed. In the case of bending, wrinkles are generated in the flange portion, which causes poor forming. In addition, in the case of deep drawing, wrinkles are generated in the top plate portion, which causes poor forming.

[0007] As a countermeasure to this problem, for example, there are a method for manufacturing a bent member and a manufacturing apparatus for a bent member described in Patent Document 1.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent No. 5733475 Gazette Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] Here, in the case of bending (Japanese: 曲げ加工), since the top plate portion is restricted by a gasket, tensile deformation and compressive deformation of the top plate portion can be suppressed. However, since the flange portion is not restricted, it is affected by tensile deformation and compressive deformation, and there is a tendency to generate wrinkles on the metal plate. In addition, in the case of deep drawing, since the flange portion is restricted by a blank holder, tensile deformation and compressive deformation of the flange portion can be suppressed. However, since the top plate portion is not restricted, it is affected by tensile deformation and compressive deformation and there is a tendency to generate wrinkles. Therefore, if the tensile / compressive deformation of the metal plate generated in the entire part shape is not considered, generation of wrinkles cannot be suppressed.

[0013] In addition, in the form method (Japanese: フォーム工法) without a gasket, since neither the top plate portion nor the flange portion is restricted, there is a tendency for both the top plate portion and the flange portion to generate large wrinkles. Therefore, forming based on the form method without a gasket is not mainly used, and many stamping parts with complex shapes are formed using a bending method, a deep drawing method (Japanese: ドロー工法), and a combined process thereof.

[0014] Here, in the method described in Patent Document 1, by restricting the top plate portion with a gasket and also restricting the flange portion with a blank holder, tensile / compressive deformation of both the top plate portion and the flange portion can be suppressed. However, it is necessary to restrict the material with a gasket on the basis of a normal deep drawing process, and the productivity is poor. In addition, the cost of the die of the method described in Patent Document 1 is also high.

[0015] The present invention addresses the aforementioned problems and aims to suppress wrinkle formation by a simple means when stamping a part into a shape having one or more curved portions with a bulging or concave top plate when viewed from the side.

[0016] Methods for solving problems

[0017] The inventors investigated a stamping method for forming a stamped part without causing cracks or wrinkles, and without requiring a complex mold structure. This stamped part has a hat-shaped cross-section and, when viewed from the side, an upwardly curved shape. The hat-shaped cross-section includes: a top plate portion; longitudinal walls formed on both sides of the top plate portion; and a flange portion continuously formed with the longitudinal walls. As a result, the following insights were obtained.

[0018] (1) By preforming to improve the shape rigidity of the die shoulder edge and forming it into the product shape by bending in the next process, wrinkles in the flange can be suppressed.

[0019] (2) In addition, by not only improving the shape rigidity of the die shoulder edge, but also improving the shape rigidity of the punch shoulder edge, and forming it into the product shape by bending in the next process, wrinkles can be suppressed not only in the flange but also in the top plate.

[0020] This invention is based on the above insights.

[0021] In order to solve the problem, one aspect of the present invention is a method for manufacturing a stamped part, wherein a metal sheet is formed into a stamped part shape, the cross section of the stamped part shape having a top plate portion and a side wall portion that is continuous with at least one of the top plate portion in the width direction via a first bending portion, and the stamped part shape having a bending portion in the length direction intersecting the cross section, i.e., a bending portion that is bulging or concave when viewed from the side, the top plate portion is bent in one or more directions. The manufacturing method comprises: a first pre-forming step, which includes a step of forming a first reinforcing rib that extends continuously or partially along the length direction on the metal sheet at the position that becomes the first bending portion; and a first part forming step, wherein the metal sheet after the first pre-forming step is formed into the stamped part shape.

[0022] Another aspect of the present invention is a method for manufacturing a stamped part, wherein a metal sheet is formed into a stamped part shape, the cross-section of which has: a top plate portion; a side wall portion that is continuous with at least one of the width directions of the top plate portion via a first bending portion; and a flange portion that is continuous with the side wall portion via a second bending portion, and the stamped part shape has a curved portion that is bulging or concave when viewed from one or more sides along a direction intersecting the cross-section, i.e., a length direction, wherein the top plate portion is bulging or concave, the manufacturing method comprising: a second pre-forming step comprising forming a second reinforcing rib that extends continuously or partially along the length direction on the metal sheet at a position that becomes the second bending portion; and a second part forming step wherein the metal sheet after the second pre-forming step is formed into the stamped part shape.

[0023] Another aspect of the present invention is a metal sheet for stamping, which is a metal sheet for stamping into the shape of a stamping component, wherein the cross section of the stamping component shape has a top plate portion and a side wall portion that is continuous with at least one of the top plate portion in the width direction via a first bending portion, and the stamping component shape has a bending portion along the length direction intersecting the cross section, i.e., a bending portion in which the top plate portion is bulging or concave when viewed from the side, and the metal sheet for stamping has a first reinforcing rib that extends continuously or partially along the length direction at the position of the first bending portion. Furthermore, one aspect of the present invention is a metal sheet for stamping, which is a metal sheet for stamping into the shape of a stamping part, wherein the cross section of the stamping part shape has: a top plate portion; a side wall portion that is continuous with at least one of the width directions of the top plate portion via a first bending portion; and a flange portion that is continuous with the side wall portion via a second bending portion, and the stamping part shape has a bending portion along the length direction intersecting the cross section, i.e., a bending portion in which the top plate portion is bulging or concave when viewed from the side, and the metal sheet for stamping has a second reinforcing rib that extends continuously or partially along the length direction at the position where the second bending portion is formed.

[0024] Invention Effects

[0025] According to the present invention, before stamping a metal sheet into a curved part shape that has an upward and downward curvature when viewed from the side, reinforcing ribs are continuously (continuously) or partially formed along at least one ridge portion that is formed by a ridge portion connecting the top plate portion and the side wall portion, or by a ridge portion forming a ridge portion connecting the side wall portion and the flange portion. As a result, according to the present invention, the shape rigidity along the length direction is improved when forming the stamped part shape, and wrinkle formation can be effectively suppressed even when stamping is performed without constraining the top plate portion and the flange portion using a die. Attached Figure Description

[0026] Figure 1 The figures shown are of the shape of a stamping part according to an embodiment of the present invention, (a) being a perspective view, (c) being a side view, and (b) being a cross-sectional view (AA).

[0027] Figure 2 This is a diagram illustrating a process example of a method for manufacturing a stamped part based on an embodiment of the present invention.

[0028] Figure 3 This is a diagram illustrating the forming surface of the mold in the pre-forming process.

[0029] Figure 4 It is a diagram illustrating the forming surface of the mold in the component forming process.

[0030] Figure 5 This is a side view diagram illustrating the cause of existing wrinkles.

[0031] Figure 6 This is a schematic diagram showing an example of a reinforcing rib after the pre-forming process, viewed from the front.

[0032] Figure 7 This is a schematic diagram illustrating wrinkle suppression based on an embodiment of the present invention, viewed from the side.

[0033] Figure 8 This is a diagram illustrating the processing steps in a modified example based on an embodiment of the present invention.

[0034] Figure 9 This is a diagram illustrating an example of how wrinkles are formed. Detailed Implementation

[0035] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] (Shape of stamped parts)

[0037] In this embodiment, the stamped part after stamping is shaped to have at least a top plate portion and sidewall portions that are continuous with at least one of its left and right width directions via a first curved portion, and has a cross-sectional shape such as a "ko"-shaped cross-section, a hat-shaped cross-section, or an "L"-shaped cross-section. Furthermore, the stamped part shape is such that, in one or more locations along the length direction intersecting the cross-section (plate width direction), the top plate portion is curved in one or more ways when viewed from the side, resulting in a bulging or concave shape. It should be noted that, in the case of a hat-shaped cross-section, the stamped part shape, when viewed from the side, also mimics the curved shape of the top plate portion.

[0038] Here, this embodiment uses a technique suitable for manufacturing stamped parts, which utilizes metal sheets formed from difficult-to-form parts such as high-tensile steel sheets or aluminum alloy sheets with tensile strength of 590 MPa or more and poor ductility and Rankford value.

[0039] It should be noted that the so-called bulging or concave curvature of the top plate when viewed from the side refers to the situation where the top plate bulges or concaves along the length direction in the thickness direction of the plate.

[0040] In this embodiment, the stamped part shape 1, which is the target after stamping, is formed as... Figure 1 The following example illustrates a stamped component shape 1 with a hat-shaped cross-section and two bends 10 along its length. That is, in this embodiment, as shown... Figure 1 As shown, the stamped part shape 1, which is the target, is exemplified by a hat-shaped cross-section having two parts along the length direction: a bent portion 10A with the top plate portion 1A concave (lower side bending) and a bent portion 10B with the top plate portion 1A convex (upper side bending). It should be noted that in this embodiment, there may be one bent portion 10, or there may be three or more bent portions 10. In addition, the bent portion 10 may have two or more parts, or the bent portions 10 of two adjacent parts may be bent in the same direction.

[0041] It should be noted that, Figure 1 The dimensions shown are for illustrative purposes only and are not intended to limit the scope of the invention.

[0042] (constitute)

[0043] like Figure 2 As shown, the manufacturing method of the stamped part in this embodiment includes a pre-forming process 2 and a part forming process 3.

[0044] <Preparation and Molding Process 2>

[0045] Preliminary forming process 2 is a process of pre-forming the metal sheet before formal forming to obtain a metal sheet that is less prone to wrinkles for formal forming.

[0046] The pre-forming process 2 includes: a first process 2A, which applies a curved shape to a flat metal sheet, mimicking the curvature of a curved portion 10 disposed on the curved portion 1 of the stamping part shape 1 along the length direction of the stamping part shape 1; and a second process 2B, which forms a first reinforcing rib 4a and a second reinforcing rib 4b at positions that become the first curved portion 1d and the second curved portion 1e. The first reinforcing rib 4a and the second reinforcing rib 4b extend continuously or partially along the length direction, respectively.

[0047] Step 2B can also be a step that forms only one of the first reinforcing rib 4a and the second reinforcing rib 4b. Alternatively, it can be configured such that the formation positions of the first reinforcing rib 4a and the second reinforcing rib 4b do not coincide in the length direction.

[0048] Alternatively, the pre-forming process 2 can also consist of only the second process 2B.

[0049] In this specification, the term "reinforcing rib extending continuously or partially along the length direction" includes both cases where reinforcing ribs are continuously formed along the entire length of the metal plate 4 and cases where reinforcing ribs are formed along a portion of the length of the metal plate 4. Multiple reinforcing ribs may also be formed at intervals along the length of the metal plate 4. For example, in the case where the stamped part shape 1 has multiple bends 10, reinforcing ribs may be continuously formed with two or more portions that are bends 10, or reinforcing ribs may be formed individually at each bend 10.

[0050] exist Figure 6 Examples of the cross-sectional shapes of the first stiffener 4a and the second stiffener 4b are shown. Figure 6 The example shown is an example of a first reinforcing rib 4a and a second reinforcing rib 4b being constructed from a full bead.

[0051] In this embodiment, the buckling shape of the reinforcing ribs 4a and 4b has a cross-section that extends along the direction intersecting the cross-section (the length direction (the length direction of the top plate portion of the metal plate 4)). The reinforcing ribs 4a and 4b are formed by full ribs, half ribs with a layered cross-section, etc.

[0052] The bending shape that mimics the bending of the bending portion 10 provided in the stamping part shape 1 adopts the profile shape when viewed from the side of the top plate portion 1A of the stamping part shape 1 (for example, the profile shape along the length direction of the ridge portion formed by the first bending portion 1d). Preferably, the radius of curvature of the bending portion 10 that imparts a bending shape to the metal plate 4 when viewed from the side is set to be equal to the radius of curvature of the bending portion 10 provided in the stamping part shape 1. Preferably, the difference between the radius of curvature of the bending portion 10 of the bending shape imparted to the metal plate 4 and the radius of curvature of the bending portion 10 provided in the stamping part shape 1 is, for example, ±10% or less of the radius of curvature of the bending portion 10 provided in the stamping part shape 1.

[0053] The first curved portion 1d corresponds to the cross-section of the ridge portion 1D formed between the top plate portion 1A and the longitudinal wall portion. This ridge portion 1D is curved in an upward convex manner. Furthermore, the second curved portion 1e corresponds to the cross-section of the ridge portion 1E formed between the longitudinal wall portion and the flange portion 1C. This ridge portion 1E is curved in an upward concave manner.

[0054] Here, the second process 2B can also be a process that forms only one of the first reinforcing ribs 4a and 4b.

[0055] In this embodiment, the first process 2A and the second process 2B are performed by stamping using a mold.

[0056] like Figure 3 As shown, the mold used imparts a bend to the forming surfaces 20 and 21 of the upper die (punch) and lower die (punch) that, when viewed from the side, have the same bend shape as the stamping part shape 1. In this embodiment, the stamping part shape 1 has a bend 10A with a concave bend (bending downwards) and a bend 10B with a convex bend (bending upwards) of the top plate portion 1A. In the shape viewed from this side, the forming surfaces 20 and 21 of the upper die (punch) and lower die (punch) have surface shapes with the portion of the top plate portion 1A that is concave (bending downwards) and the portion of the top plate portion 1A that is convex (bending upwards).

[0057] Thus, the metal plate 4 is given the same bending shape, for example, in the width direction (the same direction as the width direction of the stamping part shape 1).

[0058] Preferably, the bending shape of the forming surfaces 20 and 21 of the upper die (punch) when viewed from the side is the same as the bending shape of the top plate portion 1A when viewed from the side in the stamping part shape 1.

[0059] Typically, the curvature of the top plate portion 1A when viewed from the side along its length is equal to or approximately equal to the curvature of the flange portion 1C. Therefore, the curvature of the forming surfaces of the upper die (punch) when viewed from the side can be set to mimic the curvature of the top plate portion 1A along its length. If the curvature of the top plate portion 1A and the flange portion 1C differs when viewed from the side, the curvatures at the surface positions of the top plate portion 1A and the flange portion 1C can be set to different shapes. In this case, the difference in curvature can be absorbed by the forming surfaces forming the longitudinal wall portion.

[0060] Furthermore, the upper die (punch) and lower die (punch) forming surfaces 20 and 21 are formed with reinforcing rib shapes 20a and 21a that mimic the first reinforcing rib 4a and 20b and 21b that mimic the second reinforcing rib 4b, respectively, extending along the length direction at positions that form the first curved portion 1d and the second curved portion 1e. The positions where the first reinforcing rib shapes 20a and 21a and the second reinforcing rib shapes 20b and 21b are formed are positions in the part forming process 3 that can abut against the punch shoulder edge and the die shoulder edge of the mold in the part forming process 3.

[0061] Here, it is preferable that the first reinforcing rib 4a has a shape that bulges out in the same direction as the convex direction of the first curved portion 1d (a shape that bulges out upwards in the cross section) (see Figure 6 ).

[0062] Furthermore, it is preferable that the height of the first reinforcing rib 4a is at least twice the thickness of the metal plate 4. The upper limit of the height of the first reinforcing rib 4a is 20 mm.

[0063] Furthermore, the second reinforcing rib 4b is preferably bulging in the same direction as the convex direction of the second curved portion 1e (a downward bulging shape) (see...). Figure 6 ).

[0064] Preferably, the height of the second reinforcing rib 4b is at least twice the thickness of the metal plate 4. The upper limit of the height of the second reinforcing rib 4b is 20 mm.

[0065] Furthermore, in the pre-forming process 2, the metal plate 4 is stamped using the aforementioned upper and lower dies to form a metal plate 4 having a first reinforcing rib 4a and a second reinforcing rib 4b that are bent along the length direction and extend along the length direction.

[0066] <Component Molding Process 3>

[0067] Part forming process 3 is the formal forming process that takes the metal sheet 4, which has been processed by the pre-forming process, and forms the stamped part shape 1 with the goal of forming it.

[0068] In the component forming process 3, a die having the forming surfaces 22 and 23 shown in Figure 4 is used to stamp and form the metal plate 4 processed in the preliminary forming process 2 into a stamped component having the target stamped component shape 1.

[0069] In Figure 4 , the case where the die has a pad 24 pressing on the position of the top plate portion 1A that becomes the metal plate 4 is illustrated. That is, in this example, the case where bending forming (Japanese: 曲げ成形) is adopted as the stamping forming is illustrated. Of course, the component forming process 3 may also adopt padless bending forming without pressing the top plate portion 1A with the pad 24.

[0070] Here, the preliminary forming process 2 constitutes at least one of the first preliminary forming process and the second preliminary forming process. The component forming process 3 constitutes at least one of the first component forming process and the second component forming process.

[0071] (Actions, etc.)

[0072] In the present embodiment, as preforming, the process of giving the metal plate 4 a bending shape along the length direction (a shape bent in the plate thickness direction) and the process of giving at least one of the first reinforcing rib 4a and the second reinforcing rib 4b are performed through the preliminary forming process 2 (see Figure 3 ).

[0073] At this time, when the metal plate 4 is stamped with the upper die and the lower die used in the preliminary forming process 2, as the upper die approaches the lower die relatively, first, the metal plate 4 is deformed into a bending shape along the forming surfaces 20 and 21 of the upper die and the lower die. Further, by the upper die approaching the lower die relatively and moving to the bottom dead center, the first reinforcing rib 4a and the second reinforcing rib 4b are stamped and formed on the metal plate 4 in a bent plate shape state. That is, after giving the metal plate 4 a bending shape, the formation of the reinforcing ribs 4a and 4b is performed.

[0074] After giving the bending shape, by forming the first reinforcing rib 4a and the second reinforcing rib 4b extending along the length direction, it is possible to suppress the springback along the length direction when the bending shape given in the first process 2A is demolded to be small.

[0075] In addition, the shape rigidity of the metal plate 4 in the preliminary forming process 2 is improved due to the imparting of the reinforcing ribs 4a and 4b.

[0076] Next, when the metal plate 4 after the pre-forming process 2 is formed into a "ko"-shaped or hat-shaped cross section with a curved portion 10 that bends vertically when viewed from the side by stamping in the component forming process 3, the metal plate 4 improves the shape rigidity in the length direction by means of reinforcing ribs 4a and 4b, thus suppressing the generation of wrinkles caused by buckling.

[0077] Here, in the case where a metal plate 4 formed from a flat plate is stamped into a component shape having a curved portion 10 that bends vertically when viewed from the side, such as Figure 5 As shown, at the curved portion 10 that bulges towards the top plate portion 1A, elongation occurs in the length direction on the top plate portion 1A side (the bulging side), and contraction occurs in the length direction on the flange portion 1C side (the recessed side). Conversely, at the curved portion 10 that is recessed towards the top plate portion 1A, contraction occurs in the length direction on the top plate portion 1A side (the recessed side), and elongation occurs in the length direction on the flange portion 1C side (the bulging side).

[0078] Furthermore, along with this expansion and contraction, material movement occurs in the length direction on both the top plate portion 1A and the flange portion 1C, causing wrinkles. For example, in the case of bending forming with the top plate portion 1A constrained, there is a possibility that buckling-induced wrinkles may occur at the bend portion 10, where the flange portion 1C, where material movement is free, bulges towards the top plate portion 1A. Additionally, in the case of deep drawing forming, since the flange portion 1C is constrained, there is a possibility that buckling-induced wrinkles may occur at the bend portion 10, where the top plate portion 1A, where material movement is free, recesses towards the top plate portion 1A. In the case of unpadded bending forming, since the material movement is free in both the top plate portion 1A and the flange portion 1C, wrinkles may occur in both the top plate portion 1A and the flange portion 1C.

[0079] In this embodiment, in component forming process 3, the metal plate 4 is pre-formed... Figure 6 The first reinforcing rib 4a and the second reinforcing rib 4b improve the shape rigidity of the metal plate 4 in the longitudinal direction. As a result, during the stamping process in the component forming step 3, the generation of wrinkles caused by buckling on the metal plate 4 is suppressed, and deformation of the ridge portion 1D between the top plate portion 1A and the side wall portion 1B and the ridge portion 1E between the side wall portion 1B and the flange portion 1C is prevented.

[0080] Therefore, in this embodiment, during the stamping process in component forming step 3, such as Figure 7 As shown, the flange surface is formed by moving parallel to the stamping direction on the top plate portion 1A to suppress material movement that causes wrinkles.

[0081] Furthermore, by pre-applying a curved shape along the length direction to the metal plate 4, the flange surface is formed by moving parallel to the stamping direction on the top plate portion 1A during stamping, thereby further suppressing material movement that causes wrinkles.

[0082] (Modified example)

[0083] (1) In the above description, the case of using a mold to perform the first step 2A and the second step 2B of the pre-forming step 2 is illustrated.

[0084] Alternatively, separate molds can be used to perform steps 1 (2A) and 2 (2B). It should be noted that, in this case, it is preferable to apply the reinforcing ribs 4a and 4b in step 2 (2B) after the metal plate 4 is bent in step 1 (2A).

[0085] (2) In the above description, the case in which the first step 2A and the second step 2B are performed in the pre-forming step 2 is illustrated. The first step 2A may also be omitted in the pre-forming step 2 and only the second step 2B (the step of forming the reinforcing rib) may be performed. Furthermore, the bending shape that bends in the vertical direction when viewed from the side and the bending processing at the positions of the first bending portion 1d and the second bending portion 1e along the width direction may also be performed in the component forming step 3.

[0086] (3) In the above description, it is illustrated that the first reinforcing rib 4a and the second reinforcing rib 4b are integrally formed at the positions of the ridge portions 1D and 1E that are composed of the first curved portion 1d and the second curved portion 1e. However, the first reinforcing rib 4a and the second reinforcing rib 4b may also be provided locally at the positions of the corresponding ridge portions 1D and 1E along the length direction.

[0087] In this case, it is preferable to form each reinforcing rib at least at the positions that constitute the first and second presumed regions, wherein the first presumed region is presumed to be the region where wrinkles are generated in the top plate portion 1A when the metal plate 4 formed from the flat plate is stamped into the stamping part shape 1, and the second presumed region is presumed to be the region where wrinkles are generated in the flange portion 1C when the metal plate 4 formed from the flat plate is stamped into the stamping part shape 1.

[0088] At this time, as Figure 8 As shown, it is preferable to have a first estimated region acquisition unit 6 and a second estimated region acquisition unit 7.

[0089] The first estimated region acquisition unit 6 performs a process to determine the first estimated region, wherein the first estimated region is estimated to be the region in which wrinkles are generated in the top plate portion 1A when the metal plate 4 formed from the flat plate is stamped into the stamped part shape 1.

[0090] The second estimated region acquisition unit 7 performs a process to determine the second estimated region, wherein the second estimated region is estimated to be the region where wrinkles are generated in the flange portion 1C when the metal plate 4 formed from the flat plate is stamped into the above-mentioned stamped part shape 1.

[0091] The processing performed by the first estimated region acquisition unit 6 and the second estimated region acquisition unit 7 can be performed either in the forming analysis using a computer or in the actual stamping process.

[0092] Furthermore, since the wrinkles are generated on the side of the bending portion 10 where the material gathers during molding, the bending portion 10 where the top plate portion 1A is concave can be simply estimated as the first estimated region, and the bending portion 10 where the top plate portion 1A is convex can be estimated as the second estimated region.

[0093] (Effect)

[0094] This implementation method has the following effects.

[0095] (1) In this embodiment, the method for manufacturing a stamping part forms a metal sheet 4 into a stamping part shape 1. The cross section of the stamping part shape 1 has a top plate portion 1A and a side wall portion 1B that is continuous with at least one of the top plate portion 1A in the width direction via a first bending portion 1d. The stamping part shape 1 has a bending portion 10 that is convex or concave when viewed from one or more sides in the direction intersecting the cross section, i.e., the length direction. The manufacturing method includes: a first pre-forming step, which has a first reinforcing rib 4a that extends continuously or partially along the length direction on the metal sheet 4 at the position that becomes the first bending portion 1d; and a first part forming step, wherein the metal sheet 4 after the first pre-forming step is formed into the stamping part shape 1.

[0096] According to this configuration, before stamping the part into shape 1, which has an up-and-down curved shape when viewed from the side, a first reinforcing rib 4a is formed in advance along the ridge line formed by the curved portion connecting the top plate portion 1A and the side wall portion 1B. This improves the shape rigidity along the length direction when the part is formed into shape 1, and at least suppresses the generation of wrinkles in the top plate portion 1A.

[0097] (2) The cross section of the above-mentioned stamped part has a flange portion that is continuous with the above-mentioned side wall portion via the second bending portion. The first pre-forming process includes a process of forming the above-mentioned first reinforcing rib and a process of forming the second reinforcing rib, wherein the second reinforcing rib extends continuously or partially along the length direction on the above-mentioned metal plate at the position where the second bending portion is formed.

[0098] According to this configuration, the shape rigidity of the ridge portion on the top plate portion 1A side and the ridge portion on the flange side along the length direction is improved, thereby suppressing the generation of wrinkles in the top plate portion 1A and the flange portion 1C.

[0099] (3) The first reinforcing rib and the second reinforcing rib extend locally at least at the position where the bending portion is formed, and the position where the bending portion of the first reinforcing rib is formed is different from the position where the bending portion of the second reinforcing rib is formed.

[0100] This configuration reduces the number of locations where reinforcing ribs can be formed.

[0101] (4) Preferably, the first reinforcing rib 4a is bulging in the same direction as the convex direction of the first curved portion 1d.

[0102] Based on this configuration, the reinforcing rib shape of the first reinforcing rib 4a can be easily crushed during the component forming process 3. It should be noted that the target stamped component shape 1 can also be a shape in which the reinforcing rib is formed along the ridge connecting the top plate portion 1A and the side wall portion 1B.

[0103] It should be noted that since the top plate portion 1A is the surface that connects with other components, it is preferable not to form reinforcing ribs.

[0104] (5) The first pre-forming process may also include the following processes: applying a bend to the metal plate 4 that imitates the bend of the curved portion 10 along the length direction; and forming the first reinforcing rib 4a.

[0105] According to this configuration, the first pre-forming process, together with the first reinforcing rib 4a, is given a curved shape, for example, the shape accuracy in the length direction is improved.

[0106] (6) In this embodiment, it may also be configured as follows: a first estimated region acquisition unit 6 is provided to determine the first estimated region. The first estimated region is estimated to be the region where wrinkles are generated in the top plate portion 1A when the metal plate 4 formed from the flat plate is stamped into the stamping part shape 1. In the first pre-forming process, the first reinforcing rib 4a is partially formed in the metal plate 4 portion that corresponds to the curved portion in the ridge portion formed by the curved portion and includes the region that becomes the first estimated region.

[0107] According to this configuration, it is possible to prevent the first reinforcing rib 4a from being applied to a degree exceeding the required limit.

[0108] (7) Preferably, the height of the first reinforcing rib 4a is more than twice the thickness of the metal plate 4.

[0109] Based on this configuration, the shape rigidity in the length direction can be reliably improved.

[0110] (8) In this embodiment, it may also be configured to include a second estimated region acquisition unit 7 for determining the second estimated region, which is estimated to be the region where wrinkles are generated in the flange portion 1C when the metal plate 4 formed from the flat plate is stamped into the stamping part shape 1. In the first pre-forming process, the second reinforcing rib 4b is partially formed in the ridge portion formed by the second curved portion 1e and in the metal plate 4 portion corresponding to the second curved portion 1e that includes the region that becomes the second estimated region.

[0111] According to this configuration, it is possible to prevent the second reinforcing rib 4b from being applied to a degree exceeding the required limit.

[0112] (9) In this embodiment, it may also be a method for manufacturing a stamped part, wherein a metal sheet 4 is formed into a stamped part shape 1, the cross section of which has: a top plate portion 1A; a side wall portion 1B, which is continuous with at least one of the width directions of the top plate portion 1A via a first bending portion 1d; and a flange portion 1C, which is continuous with the side wall portion 1B via a second bending portion 1e, and the stamped part shape 1 has a curved portion 10 along the length direction intersecting the cross section, i.e., the top plate portion 1A is bulging or concave when viewed from the side. The manufacturing method includes: a second pre-forming step, in which a second reinforcing rib 4b is formed on the metal sheet 4 at the position that becomes the second bending portion 1e along the length direction, which extends continuously or partially; and a second part forming step, wherein the metal sheet 4 after the second pre-forming step is formed into the stamped part shape 1.

[0113] According to this configuration, before stamping into a stamped part shape 1 that has an upward and downward curved shape when viewed from the side, a second reinforcing rib 4b is formed in advance along the position of the ridge portion formed by the curved portion connecting the side wall portion 1B and the top plate portion 1A. This improves the shape rigidity along the length direction when forming into a stamped part shape 1, and at least suppresses the generation of wrinkles at the flange portion 1C.

[0114] (10) The second pre-forming process may also include the following processes: a process of applying a bend to the metal plate 4 along the length direction to imitate the bend of the curved portion 10; and a process of forming the second reinforcing rib 4b.

[0115] According to this configuration, the second pre-forming process and the second reinforcing rib 4b are together given a curved shape, thereby improving the shape accuracy in the length direction, for example.

[0116] (11) In this embodiment, a second estimated region acquisition unit 7 may also be provided to determine the second estimated region. The second estimated region is estimated to be the region where wrinkles are generated in the flange portion 1C when the metal plate 4 formed from the flat plate is stamped into the stamping part shape 1. The second pre-forming process is configured to partially form the second reinforcing rib 4b in the ridge portion formed by the second curved portion 1e and the portion of the metal plate 4 that includes the region that becomes the second estimated region.

[0117] According to this configuration, it is possible to prevent the second reinforcing rib 4b from being applied to a degree exceeding the required limit.

[0118] (12) Preferably, the second reinforcing rib 4b is recessed in the same direction as the concave direction of the second curved portion 1e.

[0119] Based on this configuration, the reinforcing rib shape of the second reinforcing rib 4b can be easily crushed during the component forming process 3. It should be noted that the target stamped component shape 1 can also be formed with reinforcing ribs along the ridge line connecting the side wall portion 1B and the flange portion 1C.

[0120] (13) Preferably, the height of the second reinforcing rib 4b is more than twice the thickness of the metal plate 4.

[0121] Based on this configuration, the shape rigidity in the length direction can be reliably improved.

[0122] (14) This embodiment may also be a metal plate 4 for stamping into a stamping part shape 1, the cross section of which has a top plate portion 1A and a side wall portion 1B that is continuous with at least one of the top plate portion 1A in the width direction via a first bending portion 1d, and has a bending portion 10 that is bulging or concave when viewed from the side along the direction intersecting the cross section, i.e., the length direction, and has a first reinforcing rib 4a that extends continuously or partially along the length direction at the position of the first bending portion 1d.

[0123] According to this configuration, wrinkles generated at least in the top plate portion 1A when stamping into stamped part shape 1 can be suppressed. The cross section of the stamped part shape 1 has a top plate portion 1A and a side wall portion 1B that is continuous with at least one of the top plate portion 1A in the width direction via a first bending portion 1d. The stamped part shape 1 has a bending portion 10 that is bulging or concave when viewed from one or more sides along the length direction intersecting the cross section.

[0124] (15) In addition, the metal plate 4 may also be a stamped part shape 1 of the above-mentioned stamped part 4 having a cross section of flange portion 1C that is continuous with the above-mentioned side wall portion 1B via the second curved portion 1e. The metal plate 4 is configured to have a second reinforcing rib 4b that extends along the length direction at the position of the second curved portion 1e, together with the first reinforcing rib 4a.

[0125] According to this configuration, wrinkles generated in the top plate portion 1A and the flange portion 1C during stamping into a stamped part shape 1 can be suppressed. The cross section of the stamped part shape 1 has a top plate portion 1A and a side wall portion 1B that is continuous with at least one of the top plate portion 1A in the width direction via a first bending portion 1d. The stamped part shape 1 has a bending portion 10 that is bulging or concave when viewed from the side along the length direction intersecting the cross section.

[0126] (16) In addition, the metal plate 4 may also be configured to have a bend that imitates the bend of the curved portion 10 along the length direction.

[0127] According to this configuration, when stamping into stamped part shape 1, the shape accuracy in the length direction is improved.

[0128] (17) In this embodiment, the metal plate 4 is used to stamp and form a stamped part shape 1, the cross section of which has: a top plate portion 1A; a side wall portion 1B, which is continuous with at least one of the width directions of the top plate portion 1A via a first bending portion 1d; and a flange portion 1C, which is continuous with the side wall portion 1B via a second bending portion 1e, and the stamped part shape 1 has a curved portion 10 that is convex or concave when viewed from the side along one or two or more directions intersecting the cross section, i.e., the length direction. The metal plate 4 may also be formed to have a second reinforcing rib 4b extending along the length direction at the position of the second bending portion 1e.

[0129] According to this configuration, wrinkles generated at least in the flange portion 1C can be suppressed when the stamping part is formed into a stamping part shape 1. The cross section of the stamping part shape 1 has a top plate portion 1A and a side wall portion 1B that is continuous with at least one of the top plate portion 1A in the width direction via a first bending portion 1d. The stamping part shape 1 has a bending portion 10 that is bulging or concave when the top plate portion 1A is viewed from one or more sides along the length direction intersecting the cross section.

[0130] (18) In addition, the metal plate 4 may also be configured to have a bend that imitates the bend of the curved portion 10 along the length direction.

[0131] According to this configuration, when stamping into stamped part shape 1, the shape accuracy in the length direction is improved.

[0132] Example

[0133] Next, embodiments of stamping based on the above-described embodiments of the present invention will be described. It should be noted that the present invention is not limited to the following embodiments.

[0134] "Applied Materials"

[0135] In this embodiment, a high-tensile steel plate with a strength of 590 MPa or higher is used as the metal plate 4.

[0136] Specifically, as shown in Table 1, metal plate 4 uses 590MPa grade steel plate (590 material), 980MPa grade steel plate (980 material), 1180MPa grade steel plate (1180 material) and 1470MPa grade steel plate (1470 material).

[0137] Table 1

[0138]

[0139] Metal plate 4 is a flat plate with a width W = 240mm, a length L = 387mm, and a thickness of 1.0mmt.

[0140] Furthermore, in this embodiment, the shape of the stamping component being targeted is set as follows: Figure 1 The hat-shaped cross-section shown has a curved portion 10 at two locations along the length direction when viewed from the side.

[0141] Furthermore, in the comparative examples, the flat metal sheet was directly stamped into the aforementioned stamped part shape using the forming methods shown in Table 2. In the inventive examples based on the present invention, the metal sheet was stamped into the aforementioned stamped part shape using the forming methods shown in Table 3. That is, in the forming methods of the comparative examples, the pre-forming step 2 was omitted, and the flat sheet metal was stamped into the target stamped part shape 1 using the part forming step 3 (formal forming step). In the forming method of the inventive examples based on the present invention, based on this embodiment, the target stamped part shape is formed by the part forming step 3 after the pre-forming step 2. The results are shown in Tables 2 and 3.

[0142] Table 2 shows the evaluation results of the molding method for the comparative examples (molding success or failure).

[0143] Table 3 shows the evaluation results (molding feasibility) of the molding method in the invention examples.

[0144] It should be noted that in the table, P pressure is the pad pressure and C pressure is the buffer pad pressure.

[0145] Table 2

[0146]

[0147] Table 3

[0148]

[0149] Here, the evaluation of the molded products is carried out visually, and is evaluated using three levels: “○”, “△”, and “×”. The evaluation results are recorded in Tables 2 and 3.

[0150] Specifically, in the evaluation, cases with significant wrinkles are marked as "×", cases with slight wrinkles but no significant wrinkles are marked as "△", and cases with no wrinkles are marked as "○".

[0151] <Comparative Example>

[0152] In the comparative forming method, as shown in Table 2, when using a steel plate with a tensile strength of 980 MPa or more, significant wrinkles are produced in at least one of the top plate portion 1A or the flange portion 1C.

[0153] In the comparative example, an example of wrinkles occurring at the top plate portion 1A and the flange portion 1C when using 1180 material for unpadded bending forming is shown. Figure 9 .

[0154] <Example of Invention>

[0155] On the other hand, in the inventive example, as shown in Table 3, compared with the comparative example, it can be seen that the wrinkling at the locations where the first reinforcing rib 4a and the second reinforcing rib 4b are provided is improved.

[0156] Here, the shape after the pre-forming step 2 in each invention example will be described.

[0157] Example No. 1 is an example of giving a curved shape and giving a first reinforcing rib 4a and a second reinforcing rib 4b formed by the whole rib to the first curved part 1d and the second curved part 1e, respectively.

[0158] It should be noted that the height of the reinforcing ribs 4a and 4b is set to 5 times the plate thickness. The same applies in other invention examples.

[0159] In addition, No.2 is an example of giving a curved shape and giving the first curved portion 1d a first reinforcing rib 4a formed by a half rib and the second curved portion 1e a second reinforcing rib 4b formed by a full rib.

[0160] In addition, No.3 is an example of giving a curved shape and not forming a first reinforcing rib 4a in the first curved portion 1d, but giving a second reinforcing rib 4b formed by a full rib to the second curved portion 1e.

[0161] In addition, No. 4 is an example of giving a curved shape, and not forming a first reinforcing rib 4a made of full reinforcing rib in the first curved portion 1d, and not forming a second reinforcing rib 4b in the second curved portion 1e.

[0162] In addition, No. 5 is an example of giving a curved shape, and giving the first curved portion 1d a first reinforcing rib 4a formed by a half-rib and the second curved portion 1e a second reinforcing rib 4b formed by a half-rib.

[0163] In addition, No. 6 is an example in which a curved shape is not given, a first reinforcing rib 4a formed by a full reinforcing rib is not formed in the first curved portion 1d, and a second reinforcing rib 4b is not formed in the second curved portion 1e.

[0164] Furthermore, No. 7 is an example in which a first reinforcing rib 4a, formed of a single reinforcing rib, is provided only at the location of the concave curved portion 10A in the first curved portion 1d, and a second reinforcing rib 4b, formed of a single reinforcing rib, is provided only at the location of the convex curved portion 10B in the second curved portion 1e, along the length direction. In No. 7, the location of the curved portion 10A with the first reinforcing rib 4a differs from the location of the convex curved portion 10B with the second reinforcing rib 4b in the length direction.

[0165] As can be seen from No.1, when a curved shape is given and a first reinforcing rib 4a and a second reinforcing rib 4b formed by a full-rib are respectively given to the first curved portion 1d and the second curved portion 1e, no wrinkles are generated in the top plate portion 1A and the flange portion 1C.

[0166] At this time, as shown in No.7, even if the first reinforcing rib 4a and the second reinforcing rib 4b, which are formed by the whole rib, are only locally applied to the area where wrinkles are presumed to occur, wrinkles will not occur in the top plate portion 1A and the flange portion 1C.

[0167] Furthermore, as shown in No. 2, when the first reinforcing rib 4a is set as a half-rib and the second reinforcing rib 4b is set as a full-rib, no wrinkles are generated in the flange portion 1C, but wrinkles are generated in the top plate portion 1A during unpadded bending (Japanese: フォーム) molding. This is because, although the shape rigidity on the top plate portion 1A side is improved, it is lower than that in No. 1. It should be noted that, compared with the comparative example (Table 2), the degree of wrinkling in the top plate portion 1A is slight, and even the half-rib has a wrinkle-reducing effect.

[0168] Furthermore, as shown in No.3, when only the second reinforcing rib 4b is provided, wrinkles at the flange portion 1C can be suppressed.

[0169] Furthermore, as shown in No.4, when only the first reinforcing rib 4a is provided, the generation of wrinkles at the top plate portion 1A can be suppressed.

[0170] Furthermore, as shown in No. 5, when the first reinforcing rib 4a is a full rib and the second reinforcing rib 4b is a half rib, no wrinkles are generated in the top plate portion 1A, but wrinkles are generated in the flange portion 1C. This is because, although the shape rigidity is increased on the flange portion 1C side, it is reduced compared to No. 1. It should be noted that, compared to the comparative example (Table 2), the degree of wrinkling in the flange portion 1C is slight, and even the half rib has a wrinkle reduction effect.

[0171] Hereinafter, a limited number of embodiments have been described, but the scope of the claims is not limited thereto, and changes based on the above-disclosed embodiments will be obvious to those skilled in the art.

[0172] Furthermore, the entire contents of Japanese Patent Application 2020-039600 (filed on March 9, 2020), which claims priority in this application, are incorporated herein by reference.

[0173] Explanation of reference numerals in the attached figures

[0174] 1. Shape of stamped parts

[0175] 1A Top Plate Section

[0176] 1B Sidewall

[0177] 1C Flange

[0178] 1D, 1E Ridge Section

[0179] 1d First bend

[0180] 1e Second bend

[0181] 2. Pre-forming process (first pre-forming process, second pre-forming process)

[0182] 2A Process 1

[0183] 2B Second Process

[0184] 3. Component forming process (component forming process 1 and component forming process 2)

[0185] 4 metal plates

[0186] 4a First stiffener

[0187] 4b Second reinforcing rib

[0188] 6. First Presumed Region Acquisition Department

[0189] 7. Second Presumed Region Acquisition Department

[0190] 10, 10A, 10B Bends

Claims

1. A method of manufacturing a stamped part, wherein, A metal sheet is formed into a press part shape, a cross section of the press part shape has a top plate portion and a side wall portion continuous with at least one of width directions of the top plate portion via a first curved portion, and the press part shape has one or more curved portions in which the top plate portion is convexly or concavely curved when viewed from one side along a direction intersecting the cross section, i.e., a length direction, The manufacturing method is characterized by comprising: a first preliminary forming process including a process of forming a first reinforcement rib including a plurality of reinforcement ribs on the metal sheet at a position to be the first curved portion, the plurality of reinforcement ribs being locally formed at intervals along the length direction and each extending along the length direction; and a first part forming process in which the metal sheet after the first preliminary forming process is formed into the press part shape. The cross section of the press part shape has a flange portion continuous with the side wall portion via a second curved portion, 2. The method of manufacturing a press part according to claim 1, characterized by The first preliminary forming process includes a process of forming the first reinforcement rib and a process of forming a second reinforcement rib extending continuously or locally along the length direction on the metal sheet at a position to be the second curved portion. The first reinforcement rib and the second reinforcement rib each locally extend at least at a position to be the curved portion, 3. The method of manufacturing a press part according to claim 2, characterized in that, The position to be the curved portion in which the first reinforcement rib is formed and the position to be the curved portion in which the second reinforcement rib is formed are different. The shape of the first reinforcement rib is a shape convex in the same direction as a convex direction of the first curved portion.

4. The method of manufacturing a press part according to any one of claims 1 to 3, characterized in that, The first preliminary forming process further includes a process of imparting a bend mimicking a bend of the curved portion along the length direction to the metal sheet.

5. The method of manufacturing a press part according to any one of claims 1 to 4, characterized in that, A reinforcement rib height of the first reinforcement rib is two times or more the sheet thickness of the metal sheet.

6. The method of manufacturing a press part according to any one of claims 1 to 5, characterized in that, A metal sheet is formed into a press part shape, a cross section of the press part shape has a top plate portion, a side wall portion continuous with at least one of width directions of the top plate portion via a first curved portion, and a flange portion continuous with the side wall portion via a second curved portion, and the press part shape has one or more curved portions in which the top plate portion is convexly or concavely curved when viewed from one side along a direction intersecting the cross section, i.e., a length direction, 7. A method of manufacturing a stamped part, wherein, The manufacturing method is characterized by comprising: a second preliminary forming process including a process of forming a second reinforcement rib including a plurality of reinforcement ribs on the metal sheet at a position to be the second curved portion, the plurality of reinforcement ribs being locally formed at intervals along the length direction and each extending along the length direction; and a second part forming process in which the metal sheet after the second preliminary forming process is formed into the press part shape. The second preliminary forming process includes a process of imparting a bend mimicking a bend of the curved portion along the length direction to the metal sheet and a process of forming the second reinforcement rib.

8. The method of manufacturing a press part according to claim 7, characterized by The shape of the second reinforcement rib is a shape concave in the same direction as a concave direction of the second curved portion.

9. The method of manufacturing a press part according to claim 7 or 8, characterized in that, A reinforcement rib height of the second reinforcement rib is two times or more the sheet thickness of the metal sheet.

10. The method of manufacturing a press part according to any one of claims 7 to 9, characterized in that, ​ 11. A metal sheet for press forming into a shape of a press part, wherein The cross section of the stamped part shape has a top plate portion and a side wall portion continuous with at least one of the width directions of the top plate portion via a first curved portion, and the stamped part shape has, in a length direction intersecting the cross section, one or more curved portions in which the top plate portion is convexly or concavely curved when viewed from the side, The metal sheet for press forming is characterized in that, The first reinforcing rib including a plurality of reinforcing ribs is locally formed at intervals along the length direction, and each extends along the length direction.

12. The metal sheet for press forming according to claim 11, characterized by The metal sheet is a metal sheet press-formed into the stamped part shape having, in the cross section, a flange portion continuous with the side wall portion via a second curved portion, The metal sheet has the first reinforcing rib and a second reinforcing rib which continuously or locally extends along the length direction at a position where the second curved portion is formed.

13. The sheet metal for press forming according to claim 11 or 12, characterized in that, Has a curve which imitates the curve of the curved portion along the length direction.

14. A metal sheet for press forming, which is a metal sheet for press forming into a shape of a press part, wherein The cross section of the stamped part shape has a top plate portion, a side wall portion continuous with at least one of the width directions of the top plate portion via a first curved portion, and a flange portion continuous with the side wall portion via a second curved portion, and the stamped part shape has, in a length direction intersecting the cross section, one or more curved portions in which the top plate portion is convexly or concavely curved when viewed from the side, The metal sheet for press forming is characterized in that, The second reinforcing rib including a plurality of reinforcing ribs is locally formed at intervals along the length direction, and each extends along the length direction.

15. The sheet metal for press forming according to claim 14, characterized by Has a curve which imitates the curve of the curved portion along the length direction.

16. A high-tensile steel sheet having a tensile strength of 590 MPa or more, which is used in the manufacturing method of the stamped part according to any one of claims 1 to 10.

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