Press molding apparatus and method for manufacturing press molding article

Abstract

The present disclosure relates to a press forming device provided with a clamping structure configured to clamp a workpiece, and a die for press forming the workpiece. The workpiece is a member in which a first steel plate and a second steel plate are joined to each other by butt welding. The butt welding is performed by abutting the end face of the first steel plate and the end face of the second steel plate at the boundary between the first steel plate and the second steel plate. The clamping structure is configured so as to clamp a first region including both a first steel plate and a second steel plate adjacent to the boundary and not clamp a second region further from the boundary than the first region, the first region and the second region being specific regions on the workpiece, the first region including both the first steel plate and the second steel plate adjacent to the boundary, and the second region being a region further from the boundary than the first region. The second region includes at least one of the first steel plate and the second steel plate adjacent to the first region.

Description

[0001] This application claims priority from Japanese Patent Application No. JP2024-016323, filed on February 6, 2024, and cites the entire text of the aforementioned Japanese patent application. Technical Field

[0002] The present disclosure relates to a stamping and forming apparatus. Background Art

[0003] One known method of stamping is to use tailor-welded blanks as workpieces. Tailor-welded blanks are formed by butt-welding two steel plates together to form a single piece. For example, Japanese Patent Application Laid-Open No. 2006-218501 discloses a technique for performing stamping by sandwiching the tailor-welded blanks between a punch and a counter-punch. Summary of the Invention

[0004] In the prior art disclosed in Japanese Patent Application Laid-Open No. 2006-218501, there are cases where the thickness or strength of the two steel sheets in a tailor-welded blank differ significantly, or where only one of the two steel sheets in the tailor-welded blank is clamped by the punch and counter-punch. In these cases, when the tailor-welded blank is used as a workpiece for stamping, stress is concentrated on one of the steel sheets, causing deformation and fracture.

[0005] In one embodiment of the present disclosure, it is desired to suppress unnecessary deformation of a workpiece formed by butt-welding two steel plates during a stamping process. One embodiment of the present disclosure is a stamping device comprising: a clamping structure configured to clamp a workpiece; and a die for stamping the workpiece. The workpiece is a component in which a first steel plate and a second steel plate are joined to each other by butt welding. Butt welding is welding performed by butting the end face of the first steel plate with the end face of the second steel plate at the boundary between the first steel plate and the second steel plate. The clamping structure is configured to clamp a first region and not clamp a second region, wherein the first region and the second region are specific regions on the workpiece, the first region includes both the first steel plate and the second steel plate adjacent to the boundary, the second region is a region farther from the boundary than the first region, and the second region includes at least one of the first steel plate and the second steel plate adjacent to the first region.

[0006] According to the above configuration, stamping is performed while the butt-welded portions of the first and second steel plates are clamped by the clamping structure. Moreover, since there is an area not clamped by the clamping structure, the area of the area clamped by the clamping structure is smaller than when the workpiece is clamped as a whole. As a result, the pressure applied by the clamping structure to the first and second steel plates increases. Therefore, during stamping, the movement of the first and second steel plates in the area clamped by the clamping structure can be suppressed, thereby suppressing unnecessary deformation of the workpiece formed by the butt-welding of the two steel plates.

[0007] In one aspect of the present disclosure, the clamping structure may clamp the workpiece along a boundary.

[0008] According to the clamping, the welded portions of the first and second steel plates are clamped by the clamping structure while being press-formed. Therefore, during press-forming, movement of the first and second steel plates can be suppressed, thereby suppressing unnecessary deformation of the workpiece.

[0009] In one aspect of the present disclosure, the clamping structure may be configured to clamp an end portion of a weld line of the workpiece, the weld line being a portion to be butt-welded.

[0010] According to the above configuration, during stamping, the area of the portion of the workpiece clamped by the clamping structure is small, thereby increasing the pressure applied by the clamping structure to the first and second steel plates. Therefore, during stamping, the movement of the first and second steel plates can be suppressed, thereby suppressing unnecessary deformation of the workpiece formed by butt-welding the two steel plates.

[0011] In one aspect of the present disclosure, the first steel plate and the second steel plate may differ from each other in at least one of plate thickness and strength.

[0012] By press-forming the workpiece including the first and second steel plates using the press-forming apparatus, unnecessary deformation of the workpiece can be suppressed.

[0013] In one embodiment of the present disclosure, the first and second steel plates may have different thicknesses. The clamping structure may include a step corresponding to the thickness difference between the first and second steel plates, so that the clamping structure can clamp the surfaces of both the first and second steel plates. The step may be provided along the thickness direction of the first and second steel plates.

[0014] According to the above configuration, since both the first steel plate and the second steel plate are clamped by the clamping structure, it is possible to suppress unnecessary deformation of the workpiece formed by welding two steel plates having different plate thicknesses.

[0015] In one aspect of the present disclosure, the first region may be smaller than the second region.

[0016] According to the above configuration, the area of the first region clamped by the clamping structure is small, thereby increasing the pressure applied to the workpiece by the clamping structure. Therefore, during stamping, the movement of the first and second steel plates can be suppressed, thereby suppressing unnecessary deformation of the workpiece formed by the butt welding of the two steel plates.

[0017] One embodiment of the present disclosure is a method for manufacturing a stamped product, which includes clamping a workpiece. The workpiece is a component in which a first steel plate and a second steel plate are joined to each other by butt welding. The method for manufacturing a stamped product also includes stamping at least one of the first steel plate and the second steel plate along the plate thickness direction. Butt welding is welding performed by butting the end face of the first steel plate with the end face of the second steel plate at the boundary between the first steel plate and the second steel plate. Clamping includes clamping the first area and not clamping the second area, wherein the first area and the second area are specific areas on the workpiece, the first area includes both the first steel plate and the second steel plate adjacent to the boundary, the second area is an area farther away from the boundary than the first area, and the second area includes at least one of the first steel plate and the second steel plate adjacent to the first area.

[0018] According to the above-mentioned manufacturing method, the same effects as those of the above-mentioned press forming device can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a three-dimensional diagram of a stamped product.

[0020] Figure 2 This is a top view of a stamped product.

[0021] Figure 3A It is a cross-sectional view of the stamping forming device and the tailor-welded blank in the configuration process; Figure 3B This is a cross-sectional view of the press forming device and the tailor-welded blank during the recess forming step.

[0022] Figure 4A It is a cross-sectional view of the stamping forming device and the tailor-welded blank in the clamping process; Figure 4B This is a cross-sectional view of the press forming device and tailor-welded blanks during the wall forming process.

[0023] Figure 5 This is a flowchart showing a method for manufacturing a press-formed product.

[0024] Figure 6 It is a cross-sectional view of a second punch having a step and a tailor-welded blank in a wall portion forming step according to another embodiment.

[0025] Figure 7 It is a cross-sectional view of a spacer having a step and a tailor-welded blank in a wall forming step according to another embodiment.

[0026] Figure 8 It is a cross-sectional view of a second punch having a step, a spacer, and a tailor-welded blank in a wall portion forming step according to another embodiment.

[0027] Figure 9 It is a diagram for explaining a state in which the end portion of the welding wire is clamped in another embodiment. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0029] The embodiments of the present disclosure are not limited to the following embodiments, and various embodiments can be adopted within the technical scope of the present disclosure.

[0030] [1. First embodiment]

[0031] [1-1. Structure]

[0032] [1-1-1. Composition of stamped products]

[0033] Figure 1 and Figure 2 The stamped product 1 shown is formed by Figure 3A The tailor-welded blank 2 shown is formed by stamping. The tailor-welded blank 2 is a blank formed by butt-welding a first steel plate 21 and a second steel plate 22a, 22b having different thicknesses, in which the first steel plate 21 and the second steel plate 22a, 22b are integrated. Stamping includes bending, drawing, and the like. The stamped product 1 is a component that constitutes a part of the center floor pan (Center Floor Pan) of an automobile. The stamped product 1 may also be a component other than the center floor pan of an automobile, such as a rocker outer panel (Rocker Outer Panel) or other floor panel (Floor Panel). The stamped product 1 may also be a component that is assembled on mechanical equipment other than an automobile.

[0034] The press-formed product 1 includes a first plate-shaped portion 11 and second plate-shaped portions 12 a and 12 b .

[0035] The first plate-like portion 11 is in the shape of a roughly rectangular plate. The first plate-like portion 11 corresponds to the first steel plate 21 in the tailor-welded blank 2 before stamping. The first plate-like portion 11 has a first end face and a second end face extending along a first direction perpendicular to the plate thickness direction, and the first end face and the second end face are respectively located on both sides of the first plate-like portion 11 in the second direction, wherein the second direction is perpendicular to both the first direction and the plate thickness direction of the first plate-like portion 11. Figure 1 and Figure 2 , the first direction and the second direction are indicated by double arrows, respectively. The two sides of the first plate-shaped portion 11 in the second direction are referred to as the first side and the second side of the first plate-shaped portion 11 in the second direction, respectively. The first side and the second side in the second direction correspond to the first end side and the second end side of the double arrows, respectively.

[0036] The second plate-like portions 12a and 12b are respectively joined to the end faces of the first plate-like portion 11 by butt welding. The second plate-like portions 12a and 12b have shapes symmetrical with respect to the first plate-like portion 11. The second plate-like portion 12a has an end face extending along the first direction. The end face is joined to the first end face of the first plate-like portion 11 by butt welding. The second plate-like portion 12b has an end face extending along the first direction. The end face is joined to the second end face of the first plate-like portion 11 by butt welding. That is, butt welding is provided at the boundaries 13a and 13b between the first plate-like portion 11 and the second plate-like portions 12a and 12b. In the stamped product 1, the portion where the first plate-like portion 11 and the second plate-like portion 12a are butt-welded is referred to as a welding line 14a, and the portion where the first plate-like portion 11 and the second plate-like portion 12b are butt-welded is referred to as a welding line 14b. The second plate-shaped portions 12a and 12b correspond to the second steel plates 22a and 22b in the tailor-welded blank 2 before press forming.

[0037] The second plate-like portions 12a and 12b respectively include butting portions 121a and 121b, wall portions 122a and 122b, and plate-like ends 123a and 123b. The butting portions 121a and 121b, wall portions 122a and 122b, and plate-like ends 123a and 123b are obtained by press-forming the second steel plates 22a and 22b.

[0038] The butting portions 121a and 121b extend in a plate shape along the first direction and the second direction. The butting portions 121a and 121b have portions joined to the first plate-shaped portion 11 by butt welding.

[0039] The walls 122a and 122b protrude from the ends of the butting portions 121a and 121b opposite to the portions joined to the first plate-shaped portion 11 in the second direction, toward the thickness direction of the second plate-shaped portions 12a and 12b, respectively, and extend along the first direction. The walls 122a and 122b are provided near the weld lines 14a and 14b.

[0040] The plate-shaped end portions 123 a and 123 b extend from ends of the wall portions 122 a and 122 b opposite to the ends of the connecting butting portions 121 a and 121 b , respectively, in a direction away from the first plate-shaped portion 11 in the second direction.

[0041] One or more recesses 15 are formed on the surface of the first plate-like portion 11, and the recesses 15 are recessed along the plate thickness direction of the first plate-like portion 11. The depth of the recesses 15 is less than the length of the wall portions 122a, 122b protruding from the docking portions 121a, 121b, and is less than the plate thickness of the first plate-like portion 11. The recesses 15 can be formed at least partially on the surfaces of the second plate-like portions 12a, 12b across the boundaries 13a, 13b. The shape of the cross section of the recesses 15 perpendicular to the plate thickness direction is not particularly limited, and for example, can be roughly circular or roughly rectangular. The recesses 15 may not be formed on the first plate-like portion 11 and the second plate-like portions 12a, 12b.

[0042] [1-1-2. Structure of Tailor-Welded Blanks]

[0043] The stamped product 1 is formed by using stamping devices 5a, 5b (see Figure 3A 、 Figure 3B 、 Figure 4A ,as well as Figure 4B ) is formed by stamping the tailor-welded blank 2.

[0044] The tailor-welded blank 2 is a blank formed integrally by joining a first steel plate 21 and second steel plates 22a and 22b having different thicknesses by butt welding.

[0045] The first steel plate 21 is a generally rectangular plate-shaped member. As an example, the thickness of the first steel plate 21 is 0.6 mm, and the tensile strength of the first steel plate 21 is 270 MPa. The first steel plate 21 has a first end surface and a second end surface extending along the first direction. The first end surface and the second end surface are located on either side of the first steel plate 21 in the second direction. The two sides of the first steel plate 21 in the second direction refer to the first side and the second side of the first steel plate 21 in the second direction.

[0046] The second steel plates 22a and 22b are plate-shaped components. They are made of high-strength steel. The thickness of the second steel plates 22a and 22b is greater than that of the first steel plate 21. For example, the thickness of the second steel plates 22a and 22b can be at least twice the thickness of the first steel plate 21. As an example, the thickness of the second steel plates 22a and 22b is 1.8 mm, and the tensile strength of the second steel plates 22a and 22b is 780 MPa. The second steel plates 22a and 22b are each joined to the end faces of the first steel plate 21 by butt welding. The second steel plates 22a and 22b have a shape that is symmetrical with respect to the first steel plate 21. The second steel plate 22a has an end face extending in the first direction. This end face is joined to the first end face of the first steel plate 21 by butt welding. The second steel plate 22b has an end face extending in the first direction. This end face is butt-welded to the second end face of the first steel plate 21. Specifically, the butt welds are formed at the boundaries 13a, 13b between the first steel plate 21 and the second steel plates 22a, 22b. In the tailor-welded blank 2, the butt-welded portion between the first steel plate 21 and the second steel plate 22a corresponds to the weld line 14a in the stamped part 1, and the butt-welded portion between the first steel plate 21 and the second steel plate 22b corresponds to the weld line 14b in the stamped part 1.

[0047] [1-1-3. Structure of stamping device]

[0048] The method for manufacturing the press-formed product 1 includes a step of forming the recess 15 in the tailor-welded blank 2 using a press-forming device 5 a , and a step of forming the wall portions 122 a and 122 b in the tailor-welded blank 2 using a press-forming device 5 b .

[0049] like Figure 3A and Figure 3B As shown, the stamping forming device 5a includes a first punch 51a, a first die 52a, and a holder 53. The stamping forming device 5a is configured to clamp the tailored welded blank 2 from both sides of the plate thickness direction of the tailored welded blank 2. In the following, the thickness direction of the tailored welded blank 2 is referred to as the up-down direction. The plate thickness direction is not limited to the up-down direction, and can also be understood as the left-right direction or the front-back direction. The "up" and "down" in the up-down direction can also be understood interchangeably. In this embodiment, Figure 1 The vertical direction in FIG3 is the vertical direction of the stamped product 1 when it is assembled in the vehicle, so it is called the vehicle vertical direction. Figure 6 、 Figure 7 ,as well as Figure 8 The vertical direction in the figure is the vertical direction during stamping, and is therefore referred to as the stamping vertical direction. The stamping vertical direction is opposite to the vehicle vertical direction. In other words, the stamping is performed by turning the tailor-welded blank 2 forming the stamped product 1 upside down relative to the state in which the stamped product 1 is assembled in the vehicle.

[0050] The first punch 51a is a punch of a die used for press forming. The first punch 51a is located below the tailor-welded blank 2. The top surface of the first punch 51a faces the boundaries 13a and 13b of the tailor-welded blank 2, the entire first steel sheet 21, and a portion of the second steel sheets 22a and 22b.

[0051] The first punch 51a includes a first punch-side recess forming portion 511 for forming recesses 15 in the tailored welded blank 2. The first punch-side recess forming portion 511 is provided on the surface of the first punch 51a that faces the tailored welded blank 2. The first punch-side recess forming portion 511 protrudes upward. The first punch-side recess forming portion 511 is provided in the same number as the recesses 15 formed in the tailored welded blank 2.

[0052] The first die 52a is a die used in press forming and is located above the tailor-welded blank 2 so as to cover the entire tailor-welded blank 2 .

[0053] The first die 52a includes a first die-side recess forming portion 521 for forming recesses 15 in the tailored welded blank 2. The first die-side recess forming portion 521 is provided on the surface of the first die 52a that faces the tailored welded blank 2. The first die-side recess forming portion 521 is recessed upward to engage with the first punch-side recess forming portion 511. The first die-side recess forming portion 521 is provided in the same number as the recesses 15 formed in the tailored welded blank 2.

[0054] The holder 53 is a holder for supporting the tailored welded blank 2. The holder 53 is located below the tailored welded blank 2. The holder 53 is located on both sides of the first punch 51a in the second direction. The upper surface of the holder 53 faces a portion of the second steel plates 22a and 22b.

[0055] The holder 53 is configured to be movable downward together with the first concave die 52 a by being pressed downward by the first concave die 52 a positioned above the holder 53 .

[0056] like Figure 4A and 4B As shown, the press forming device 5b includes a second punch 51b, a second die 52b, and a spacer 54. The press forming device 5b is arranged to clamp the tailored welded blank 2 from both sides in the vertical direction. The tailored welded blank 2 arranged in the press forming device 5b is the tailored welded blank 2 that has been press-formed by the press forming device 5a.

[0057] The second punch 51b is a punch of a die used in press forming. The second punch 51b is located below the tailor-welded blank 2. The upper surface of the second punch 51b faces the entire tailor-welded blank 2.

[0058] The second punch 51b has second punch side wall forming portions 512a, 512b for forming the wall portions 122a, 122b on the tailor-welded blank 2. The second punch side wall forming portions 512a, 512b are provided on the surface of the second punch 51b facing the tailor-welded blank 2 and have a step in the vertical direction.

[0059] The second die 52b is a die used in press forming and is located above the tailor-welded blank 2 so as to cover the entire tailor-welded blank 2 .

[0060] The second die 52b includes second die sidewall forming portions 522a and 522b that form the wall portions 122a and 122b on the tailor-welded blank 2. The second die sidewall forming portions 522a and 522b are provided on the surface of the second die 52b that faces the tailor-welded blank 2. The second die sidewall forming portions 522a and 522b have vertical steps to engage with the second punch sidewall forming portions 512a and 512b.

[0061] The spacer 54 is used to hold the tailored welded blank 2 during press forming. The spacer 54 is positioned so as to penetrate the second die 52b. The spacer 54 is located above the tailored welded blank 2. The lower surface of the spacer 54 faces the boundaries 13a and 13b of the tailored welded blank 2, a portion of the first steel sheet 21, and a portion of the second steel sheets 22a and 22b. An air cushion (not shown) is positioned above the spacer 54. The spacer 54 is configured to hold the tailored welded blank 2 using pressure from the air cushion.

[0062] [1-2. Method for manufacturing stamped product]

[0063] like Figure 5 As shown, the manufacturing method of the stamped product 1 includes an arrangement step S10, a recessed portion forming step S20, a clamping step S30, and a wall portion forming step S40. The manufacturing method of the stamped product 1 is performed in the order of the arrangement step S10, the recessed portion forming step S20, the clamping step S30, and the wall portion forming step S40.

[0064] [1-2-1. Formation of concave portion]

[0065] Reference Figure 3A 、 Figure 3B 、 Figure 4A ,as well as Figure 4B A method for manufacturing the press-formed product 1 will be described.

[0066] The arrangement step S10 and the recessed portion forming step S20 are performed by Figure 3A and Figure 3B The press forming device 5 a shown is a process for forming the recessed portion 15 in the tailor-welded blank 2 .

[0067] like Figure 3A As shown, in the placement step S10, the tailored welded blank 2 is placed on the upper surface of the holder 53. The second steel sheets 22a and 22b in the tailored welded blank 2 partially abut the upper surface of the holder 53, thereby being supported by the holder 53. The first steel sheet 21 in the tailored welded blank 2 is spaced a certain distance from both the first punch 51a and the holder 53. The first steel sheet 21 may have a portion abutting the upper surface of the first punch 51a. The tailored welded blank 2 is spaced a certain distance from the first die 52a located above the tailored welded blank 2.

[0068] In the recess forming step S20, the first die 52a moves downward and abuts the upper surface of the tailored welded blank 2. Thereafter, the first die 52a, the tailored welded blank 2, and the retaining member 53 move downward as a whole. The tailored welded blank 2 moves downward until it abuts the first punch 51a, and then, due to the pressure from the first die 52a that moves further downward, the tailored welded blank 2 is deformed along the first punch side recess forming portion 511 of the first punch 51a and the first die side recess forming portion 521 of the first die 52a. By this stamping, the recess 15 is formed on the tailored welded blank 2, thereby obtaining the first plate-shaped portion 11 having the recess 15 (see Figure 3B ).

[0069] [1-2-2. Formation of the wall]

[0070] The clamping step S30 and the wall forming step S40 are performed by Figure 4A 、 Figure 4B The press forming device 5 b shown is a step of forming the wall portions 122 a and 122 b on the tailor-welded blank 2 .

[0071] like Figure 4A As shown, in the clamping step S30, the tailored welded blank 2 is clamped between the second punch 51b located below the tailored welded blank 2 and the spacer 54 located above the tailored welded blank 2. The tailored welded blank 2 is spaced a certain distance from the second die 52b located above the tailored welded blank 2.

[0072] The spacer 54 holds the first regions 26a and 26b of the tailored welded blank 2 along the boundaries 13a and 13b. The first regions 26a and 26b are adjacent to the boundaries 13a and 13b, including the weld lines 14a and 14b, of the tailored welded blank 2, respectively. The spacer 54 does not hold the second region 27 of the first steel sheet 21 of the tailored welded blank 2 or the second region 27 of the second steel sheets 22a and 22b. With respect to the tailored welded blank 2, the second region 27 is farther from the boundaries 13a and 13b than the first regions 26a and 26b. The second region 27 is adjacent to the first regions 26a and 26b. The first regions 26a and 26b are smaller than the second region 27.

[0073] In this embodiment, the spacers 54 hold the areas near the boundaries 13a and 13b of the tailored welded blank 2 as first areas 26a and 26b. In this embodiment, the spacers 54 do not hold areas other than the areas near the boundaries 13a and 13b of the tailored welded blank 2 as second areas 27.

[0074] In the wall forming process S40, while the tailor-welded blank 2 is clamped by the second punch 51b and the spacer 54, the second die 52b moves downward and abuts against the upper surfaces of the second steel plates 22a, 22b in the tailor-welded blank 2. Afterwards, the tailor-welded blank 2 is subjected to pressure exerted by the second die 52b further moving downward, and the tailor-welded blank 2 is deformed along the second punch side wall forming portions 512a, 512b of the second punch 51b and the second die side wall forming portions 522a, 522b of the second die 52b. By this stamping process, the wall portions 122a, 122b are formed on the tailor-welded blank 2, and the second plate-like portions 12a, 12b having the butt joints 121a, 121b, the wall portions 122a, 122b, and the plate-like ends 123a, 123b are obtained (see FIG. Figure 4B ).

[0075] In the wall portion forming step S40 , the second punch 51 b , the spacer 54 , and the first steel plate 21 of the tailor-welded blank 2 do not move.

[0076] [1-3. Actions and Effects]

[0077] According to the embodiments described above, the following actions and effects can be obtained.

[0078] (1a) In the wall forming process S40, when the tailor-welded blank 2 is deformed along the second punch sidewall forming portions 512a, 512b and the second die sidewall forming portions 522a, 522b due to the pressure from the second die 52b, a force is applied to the weld lines 14a, 14b in a direction that causes the first steel sheet 21 and the second steel sheet 22a, 22b to separate from each other in the second direction. At this time, stress may concentrate on one of the first and second steel sheets 21, 22a, 22b, causing cracks and deformation. In particular, stress concentration is more likely to occur on the first steel sheet 21, which is made of a material with a relatively thin plate thickness or a relatively low tensile strength, and thus cracks and deformation may occur.

[0079] In contrast, in the above embodiment, the spacers 54 hold the first regions 26a and 26b of the tailored welded blank 2 along the boundaries 13a and 13b. The first regions 26a and 26b are adjacent to the boundaries 13a and 13b of the tailored welded blank 2 including the weld lines 14a and 14b.

[0080] Furthermore, the spacer 54 does not sandwich the second region 27 of the first steel sheet 21 of the tailored welded blank 2 or the second region 27 of the second steel sheets 22a and 22b. With respect to the tailored welded blank 2, the second region 27 is farther from the boundaries 13a and 13b than the first regions 26a and 26b. The second region 27 is adjacent to the first regions 26a and 26b.

[0081] According to the above configuration, the area of the welded blank 2 held by the spacer 54 is reduced compared to a case where the spacer 54 simultaneously holds both the first regions 26a, 26b and the second region 27, particularly compared to a case where the spacer 54 holds the entire region of the tailored blank 2 that does not require stamping. Consequently, the pressure (hereinafter referred to as the pressing force) applied by the spacer 54 to the tailored blank 2 due to the spacer 54 holding the tailored blank 2 increases. A high pressing force can suppress movement of the first steel sheet 21 and the second steel sheet 22a, 22b in the tailored blank 2 during stamping, such as in the wall forming step S40, thereby minimizing the thickness reduction of the tailored blank 2 caused by stamping. In particular, deformation and cracking of the first steel sheet 21 and the second steel sheet 22a, 22b in the first regions 26a, 26b, including the vicinity of the weld lines 14a, 14b, can be suppressed. Consequently, unnecessary deformation of the tailored blank 2 can be suppressed.

[0082] (1b) In the clamping step S30 and the wall portion forming step S40 , the spacer 54 clamps both the first steel plate 21 and the second steel plates 22 a and 22 b .

[0083] According to the above configuration, it is possible to suppress stress concentration on either the first steel plate 21 or the second steel plates 22a, 22b during press forming. Therefore, compared to a case where the spacer 54 clamps either the first steel plate 21 or the second steel plates 22a, 22b, it is possible to suppress deformation or cracking of the tailor-welded blank 2.

[0084] (1c) The first regions 26a and 26b where the spacers 54 hold the tailor-welded blank 2 are smaller than the second region 27 where the spacers 54 do not hold the tailor-welded blank 2 .

[0085] According to the above configuration, the area of the spacer 54 holding the tailor-welded blank 2 can be further reduced, and thus the pressing force of the spacer 54 can be further increased. Consequently, unnecessary deformation of the tailor-welded blank 2 can be further suppressed.

[0086] (1d) In the above-described method for manufacturing the press-formed product 1, after the recess 15 is formed in the tailor-welded blank 2 in the arrangement step S10 and the recess forming step S20, the walls 122a and 122b are formed in the tailor-welded blank 2 in the clamping step S30 and the wall forming step S40.

[0087] According to the above process, the recess 15 is formed in the tailored welded blank 2 during the clamping step S30 and the wall forming step S40. Therefore, during the clamping step S30 and the wall forming step S40, the spacer 54 only needs to clamp the first regions 26a and 26b of the tailored welded blank 2, which are prone to deformation and cracking. It is not necessary to clamp areas other than the first regions 26a and 26b. Consequently, the area of the tailored welded blank 2 clamped by the spacer 54 can be further reduced, thereby increasing the pressing force of the spacer 54. Consequently, unnecessary deformation of the tailored welded blank 2 can be further suppressed.

[0088] [1-4. Correspondence between terms]

[0089] In the above embodiment, the tailor-welded blank 2 corresponds to an example of a workpiece, the spacer 54 and the second punch 51 b correspond to an example of a clamping structure, and the second punch 51 b and the spacer 54 correspond to a die for press-forming the workpiece.

[0090] [2. Other Implementations]

[0091] The embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above embodiments and can take various forms.

[0092] (2a) In the above embodiment, the spacers 54 hold the vicinity of the boundaries 13a and 13b in the tailor-welded blank 2 as the first regions 26a and 26b.

[0093] However, the first regions 26a and 26b of the tailor-welded blank 2 held by the spacers 54 are not limited to the vicinity of the boundaries 13a and 13b. In other words, the first regions 26a and 26b may be extended to regions other than the vicinity of the boundaries 13a and 13b.

[0094] (2b) In the above embodiment, the spacer 54 does not sandwich the second region 27 other than the vicinity of the boundaries 13 a and 13 b in the tailor-welded blank 2 .

[0095] However, the area where the spacer 54 does not hold the tailor-welded blank 2 is not limited to the above-mentioned area.

[0096] The spacer 54 may be arranged so as not to hold a portion of the area, which is located on the opposite side of the boundary 13a, 13b in the tailor-welded blank 2 and is deformed by press forming, as the second area 27. For example, in the wall forming step S40, the spacer 54 may be arranged so as not to hold a portion of the area between the boundary 13a, 13b, which is located on the opposite side of the boundary 13a, 13b in the tailor-welded blank 2 and is formed into the wall 122a, 122b by press forming.

[0097] (2c) In the above embodiment, the first areas 26a and 26b where the spacer 54 holds the laser welded plate 2 are smaller than the second area 27 where the spacer 54 does not hold the laser welded plate 2. However, the area of the first areas 26a and 26b held by the spacer 54 may be equal to or larger than the area of the second area 27. The spacer 54 needs to hold at least the areas near the weld lines 14a and 14b of both the first steel plate 21 and the second steel plates 22a and 22b, and any areas other than the areas near the weld lines 14a and 14b may be left unheld.

[0098] (2d) As in the above embodiment, when the first steel plate 21 and the second steel plates 22a, 22b in the tailor-welded blank 2 have different thicknesses, at least one of the spacer 54 and the second punch 51b may have a step corresponding to the thickness. Specifically, at least one of the spacer 54 and the second punch 51b has a step corresponding to the thickness difference between the first steel plate 21 and the second steel plates 22a, 22b in the thickness direction of the first steel plate 21 and the second steel plates 22a, 22b, so that the spacer 54 and the second punch 51b can clamp the respective surfaces of the first steel plate 21 and the second steel plates 22a, 22b.

[0099] For example, Figure 6 As shown, when there is a step on the lower surface of the boundary 13b of the tailor-welded blank 2, the second punch 251b may have a punch side step 261 corresponding to the plate thickness difference between the first steel plate 21 and the second steel plates 22a, 22b at the boundary 13b.

[0100] Or, as Figure 7 As shown, when there is a step on the upper surface of the boundary 13b of the tailor-welded blank 2, the spacer 354 may have a spacer-side step 362 corresponding to the plate thickness difference between the first steel plate 21 and the second steel plates 22a, 22b at the boundary 13b.

[0101] Or, as Figure 8 As shown, when there are steps on both the upper and lower surfaces of the boundary 13b of the tailor-welded plate 2, the second punch 251b and the pad 354 may respectively have a punch side step 261 and a pad side step 362, and the punch side step 261 and the pad side step 362 correspond to the plate thickness difference between the first steel plate 21 and the second steel plates 22a, 22b at the boundary 13b.

[0102] With the above configuration, even in a tailor-welded blank 2 composed of two steel plates having a significant difference in thickness, the second punch 251b and the spacer 354 can simultaneously clamp the surfaces of both the first steel plate 21 and the second steel plates 22a, 22b. This prevents cracks and deformation in the tailor-welded blank 2.

[0103] (2e) In the above embodiment, the first steel plate 21 and the second steel plates 22a, 22b have different plate thicknesses and tensile strengths. However, at least one of the plate thickness and tensile strength may be the same between the first steel plate 21 and the second steel plates 22a, 22b.

[0104] As an example, the first steel plate 21 and the second steel plates 22a, 22b may have the same thickness and tensile strength, and the tensile strength of the first steel plate 21 and the second steel plates 22a, 22b may both be 780 MPa or greater. In this case, the area near the weld lines 14a, 14b is susceptible to softening due to the heat from welding, and stress is likely to concentrate there. Therefore, by clamping the area near the weld lines 14a, 14b with the spacers 54, cracking and deformation of the tailor-welded blank 2 can be suppressed.

[0105] As an example, the first steel plate 21 and the second steel plates 22a, 22b may have the same thickness and tensile strength, and both may be made of stainless steel. In this case, the weld lines 14a, 14b of the tailor-welded blank 2 are susceptible to fracture during the wall forming step S40. Therefore, by clamping the areas near the weld lines 14a, 14b with the spacers 54, cracking and deformation of the tailor-welded blank 2 can be suppressed.

[0106] (2f) In the above-described embodiment, in the clamping step S30, the spacers 54 clamp the boundaries 13a, 13b of the tailor-welded blank 2, including the weld lines 14a, 14b, along the boundaries 13a, 13b. However, the spacers 54 do not need to clamp the entire boundaries 13a, 13b and weld lines 14a, 14b, but may only clamp a portion of the boundaries 13a, 13b and weld lines 14a, 14b. The spacers 54 only need to clamp the vicinity of the weld lines 14a, 14b of the tailor-welded blank 2, and do not need to directly clamp the weld lines 14a, 14b. For example, the spacers 54 may partially clamp portions of the weld lines 14a, 14b, such as the ends of the weld lines 14a, 14b, rather than clamping the entire weld lines 14a, 14b.

[0107] As an example, Figure 9 As shown in FIG. 1 , the first region 26a held by the spacer 54 may be a portion of the boundary 13a between the first steel plate 21 and the second steel plate 22a, including a portion of the weld line 14a. Figure 9 In the figure, the shaded area represents the first area 26a clamped by the spacer 54. The solid line represents the ridgeline and boundary 13a of the first steel plate 21 and the second steel plate 22a. The bold line represents the weld line 14a. The single-dot chain line represents the ridgeline of the virtual stamped product 1 after stamping. The dotted line represents the portion that forms the wall portion 122a during stamping.

[0108] According to the above configuration, the area of the spacer 54 holding the tailor-welded blank 2 can be further reduced, and thus the pressing force of the spacer 54 can be further increased. Consequently, unnecessary deformation of the tailor-welded blank 2 can be further suppressed.

[0109] (2g) In the above embodiment, the method for manufacturing the press-formed product 1 is performed in the order of the arrangement step S10, the recess forming step S20, the clamping step S30, and the wall forming step S40. However, the arrangement step S10 and the recess forming step S20 do not need to be performed before the clamping step S30 and the wall forming step S40. In particular, if the press-formed product 1 does not have the recess 15, the arrangement step S10 and the recess forming step S20 do not need to be performed.

[0110] (2h) The multiple functions of one component in the above-mentioned embodiment may be realized by multiple components, or the one function of one component may be realized by multiple components. In addition, the multiple functions of multiple components may be realized by one component, or the one function of multiple components may be realized by one component. In addition, a part of the structure of the above-mentioned embodiment may be omitted. In addition, at least a part of the structure of the above-mentioned embodiment may be added to the structure of the above-mentioned other embodiment, or at least a part of the structure of the above-mentioned embodiment may be replaced with the structure of the above-mentioned other embodiment, etc.

[0111] [Technical Ideas Disclosed in This Specification]

[0112] [Project 1]

[0113] A stamping forming device, characterized by comprising:

[0114] a clamping structure configured to clamp a workpiece; and

[0115] A mold, wherein the mold is used to stamp the workpiece.

[0116] The workpiece is a component in which a first steel plate and a second steel plate are joined to each other by butt welding.

[0117] The butt welding is performed by butting the end surface of the first steel plate and the end surface of the second steel plate at the boundary between the first steel plate and the second steel plate.

[0118] The clamping structure is configured to clamp the first area but not the second area, wherein the first area and the second area are specific areas on the workpiece, the first area includes both the first steel plate and the second steel plate adjacent to the boundary, the second area is an area farther away from the boundary than the first area, and the second area includes at least one of the first steel plate and the second steel plate adjacent to the first area.

[0119] [Project 2]

[0120] The stamping forming device according to item 1 is characterized in that

[0121] The clamping structure clamps the workpiece along the boundary.

[0122] [Item 3]

[0123] The press forming device according to item 1 or 2 is characterized in that

[0124] The clamping structure is configured to clamp an end portion of a weld line of the workpiece, the weld line being a portion to be butt-welded.

[0125] [Item 4]

[0126] The stamping forming device according to any one of items 1 to 3 is characterized in that

[0127] The first steel plate and the second steel plate are different from each other in at least one of plate thickness and strength.

[0128] [Item 5]

[0129] The stamping forming device according to item 4 is characterized in that

[0130] The first steel plate and the second steel plate have different plate thicknesses.

[0131] The clamping structure has a step corresponding to the thickness difference between the first steel plate and the second steel plate, so that the clamping structure can clamp the surfaces of both the first steel plate and the second steel plate.

[0132] The step is provided along a plate thickness direction of the first steel plate and the second steel plate.

[0133] [Item 6]

[0134] The stamping and forming device according to any one of items 1 to 5 is characterized in that

[0135] The first area is smaller than the second area.

[0136] [Item 7]

[0137] A method for manufacturing a stamped product, characterized by comprising the following steps:

[0138] clamping a workpiece, the workpiece being a component in which a first steel plate and a second steel plate are joined to each other by butt welding; and

[0139] At least one of the first steel plate and the second steel plate is press-formed along the plate thickness direction.

[0140] The butt welding is performed by butting the end surface of the first steel plate and the end surface of the second steel plate at the boundary between the first steel plate and the second steel plate.

[0141] The clamping includes clamping a first area and not clamping a second area, wherein the first area and the second area are specific areas on the workpiece, the first area includes both the first steel plate and the second steel plate adjacent to the boundary, the second area is an area farther away from the boundary than the first area, and the second area includes at least one of the first steel plate and the second steel plate adjacent to the first area.

Claims

1. A stamping forming device, characterized in that: have: a clamping structure configured to clamp a workpiece; and A mold, wherein the mold is used to stamp the workpiece. The workpiece is a component in which a first steel plate and a second steel plate are joined to each other by butt welding. The butt welding is performed by butting the end surface of the first steel plate and the end surface of the second steel plate at the boundary between the first steel plate and the second steel plate. The clamping structure is configured to clamp the first area but not the second area, wherein the first area and the second area are specific areas on the workpiece, the first area includes both the first steel plate and the second steel plate adjacent to the boundary, the second area is an area farther away from the boundary than the first area, and the second area includes at least one of the first steel plate and the second steel plate adjacent to the first area.

2. The stamping forming device according to claim 1, characterized in that The clamping structure clamps the workpiece along the boundary.

3. The stamping forming device according to claim 1, characterized in that The clamping structure is configured to clamp an end portion of a weld line of the workpiece, the weld line being a portion to be butt-welded.

4. The stamping forming device according to claim 1, characterized in that The first steel plate and the second steel plate are different from each other in at least one of plate thickness and strength.

5. The stamping forming device according to claim 4, characterized in that: The first steel plate and the second steel plate have different plate thicknesses. The clamping structure has a step corresponding to the thickness difference between the first steel plate and the second steel plate, so that the clamping structure can clamp the surfaces of both the first steel plate and the second steel plate. The step is provided along a plate thickness direction of the first steel plate and the second steel plate.

6. The stamping forming device according to any one of claims 1 to 5, characterized in that: The first area is smaller than the second area.

7. A method for manufacturing a stamped product, characterized in that: The following steps are involved: clamping a workpiece, wherein the workpiece is a component in which a first steel plate and a second steel plate are joined to each other by butt welding; as well as At least one of the first steel plate and the second steel plate is press-formed along the plate thickness direction. The butt welding is performed by butting the end surface of the first steel plate and the end surface of the second steel plate at the boundary between the first steel plate and the second steel plate. The clamping includes clamping a first area and not clamping a second area, wherein the first area and the second area are specific areas on the workpiece, the first area includes both the first steel plate and the second steel plate adjacent to the boundary, the second area is an area farther away from the boundary than the first area, and the second area includes at least one of the first steel plate and the second steel plate adjacent to the first area.

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