Pressing apparatus and method for manufacturing press-formed products

Abstract

For example, the present invention provides a press device that can manufacture press-formed products, such as the front floor of an automobile, with good moldability. [Solution] The press device (100) comprises a first die (10) and a second die (20). The first die (10) includes a punch (11), a die (12), and a holder (13). The second die (20) includes a punch (21), a pad (22), a die (23), and a holder (24). The punch (11) includes a punch side surface (113) having a height difference in the longitudinal direction of the first die (10). The punch (21) includes a punch flange surface (215) having at least a portion of an uneven shape (215a). The end of the holder (24) is located between the punch shoulder (212) and the punch flange surface (215) in the pressing direction at the top dead center of the second die (20).

Description

[Technical Field]

[0001] This disclosure relates to a press apparatus and a method for manufacturing press-formed articles. [Background technology]

[0002] Automobile body structures require not only lightweight construction for fuel efficiency but also excellent crash resistance. Within the body structure, the cabin, which serves as the occupant's living space, must have a robust structure to prevent impact debris from entering during a collision. The front floor, which forms the lower part of the cabin, also requires excellent crash resistance.

[0003] The front floor includes the floor tunnel and the floor sides. The floor tunnel extends in the longitudinal direction of the vehicle body. The floor sides are located on either side of the floor tunnel. The floor tunnel is usually made of a material that is thicker and stronger than the floor sides. This is because the floor tunnel contributes significantly to the crash characteristics of the front floor.

[0004] For example, in a frontal collision, structural components in the engine compartment, such as the bumper and floor side members, absorb the collision energy. However, any remaining load that is not absorbed by these structural components must be supported by the cabin. The floor tunnel, along with the front structural components of the cabin, such as the side sills, A-pillar lowers, and A-pillar uppers, bears the collision load. The floor tunnel needs to have high strength to prevent debris from entering the cabin. If the strength of the floor tunnel is insufficient, it may easily deform during a frontal collision, allowing debris to enter the cabin and reducing the collision characteristics of the front floor.

[0005] For example, in the event of a side collision, the collision load (collision energy) is transmitted in the order of side sill, floor cross member, and floor tunnel. The floor tunnel needs to have high strength to reliably support the side sill and floor cross member. If the strength of the floor tunnel is insufficient, the side sill and floor cross member will not be adequately supported by the floor tunnel during a side collision, and the collision characteristics of the front floor will deteriorate.

[0006] In contrast, Patent Document 1 proposes a floor tunnel aimed at improving collision characteristics against frontal collisions. The floor tunnel of Patent Document 1 has a hat-shaped open cross-section and includes a front end region and a main region located behind the front end region. In this floor tunnel, the yield strength of the front end region is smaller than the yield strength of the main region. According to Patent Document 1, when an impact load is applied to the front end region of the floor tunnel from the front of the vehicle body, the front end region, which has a relatively small yield strength, absorbs most of the load by bending, and the load, which has been significantly reduced by the plastic deformation of the front end region, is transmitted to the main region. Patent Document 1 states that because the yield strength of the main region is relatively large, the main region can withstand the remaining load without undergoing large plastic deformation. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2020 / 095756 [Overview of the project] [Problems that the invention aims to solve]

[0008] The floor tunnel used in a general automobile is formed separately from the left and right floor sides and then joined to each floor side. The floor tunnel includes a top plate, left and right vertical walls, and left and right flanges. As described in Patent Document 1, the left and right flanges of the floor tunnel are overlapped on the upper surface of the panel-shaped floor side. The left and right flanges of the floor tunnel are usually joined to the floor side by spot welding.

[0009] When the floor tunnel is joined to the floor side by spot welding, for example, when the automobile has a frontal collision, the spot weld may break and the floor tunnel may peel off from the floor side. In this case, the collision characteristics of the front floor will deteriorate.

[0010] To solve the problem of breakage of the spot weld, it is conceivable to press-form the floor tunnel and the floor side from a single sheet of plate material. For example, it is conceivable to use a tailored blank and press-form the floor tunnel and the floor side integrally and simultaneously. In this case, since there is no spot weld in the formed front floor, the problems of breakage of the spot weld and peeling between the floor tunnel and the floor side during a collision of the automobile do not occur. Therefore, the collision characteristics of the front floor can be improved. However, when the floor tunnel and the floor side are integrated from the stage of the press-forming material, the formability of the front floor deteriorates.

[0011] An object of the present disclosure is to provide a press device capable of manufacturing a press-formed product, such as the front floor of an automobile, with good formability.

Means for Solving the Problems

[0012] The press apparatus according to this disclosure comprises a first die and a second die. The first die includes a first punch, a first die, and a first holder. The second die includes a second punch, a first pad, a second die, and a second holder. The first punch includes a first punch top surface, a first punch shoulder, a first punch side surface, a first punch base, and a first punch flange surface. The first punch shoulder is continuous with the first punch top surface. The first punch side surface is continuous with the first punch shoulder. The first punch side surface has a height difference in the longitudinal direction of the first die. The first punch base is continuous with the first punch side surface on the opposite side of the first punch shoulder. The first punch flange surface is continuous with the first punch base. The first punch flange surface extends outward from the first punch base in the width direction of the first die. The first die includes a first die bottom surface, a first die bottom edge, a first die side surface, a first die shoulder, and a first die flange surface. The first die bottom surface has a shape corresponding to the first punch top surface. The first die bottom surface faces the first punch top surface. The first die bottom edge is continuous with the first die bottom surface. The first die bottom edge has a shape corresponding to the first punch shoulder. The first die side surface is continuous with the first die bottom edge. The first die side surface has a shape corresponding to the first punch side surface. The first die shoulder is continuous with the first die side surface on the opposite side of the first die bottom edge. The first die shoulder has a shape corresponding to the first punch base. The first die flange surface is continuous with the first die shoulder. The first die flange surface extends outward from the first die shoulder in the width direction of the first mold. The first die flange surface faces the first punch flange surface and the first holder. The second punch includes a second punch top surface, a second punch shoulder, a second punch side surface, a second punch base, and a second punch flange surface. The second punch top surface faces the first pad. The second punch shoulder is continuous with the second punch top surface. The second punch side surface is continuous with the second punch shoulder. The second punch base is continuous with the second punch side surface on the opposite side of the second punch shoulder. The second punch flange surface is continuous with the second punch base. The second punch flange surface extends outward from the second punch base in the width direction of the second die. The second punch flange surface has an uneven shape on at least a portion of it. The second die includes a second die bottom edge, a second die side surface, a second die shoulder, and a second die flange surface. The second die bottom edge has a shape corresponding to the second punch shoulder.The second die side is continuous with the second die bottom edge. The second die side has a shape corresponding to the second punch side. The second die shoulder is continuous with the second die side on the opposite side of the second die bottom edge. The second die shoulder has a shape corresponding to the second punch base. The second die flange surface is continuous with the second die shoulder. The second die flange surface extends outward from the second die shoulder in the width direction of the second die. The second die flange surface faces the second punch flange surface and the second holder. At the top dead center of the second die, the end of the second holder on the second die flange surface side is located between the second punch shoulder and the second punch flange surface in the pressing direction of the second die. [Effects of the Invention]

[0013] According to the press apparatus described herein, press-formed products such as the front floor of an automobile can be manufactured with good formability. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic diagram showing a press apparatus for press-formed products according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view showing the schematic configuration of the first die included in the press apparatus shown in Figure 1. [Figure 3] Figure 3 is a magnified view of the first mold shown in Figure 2. [Figure 4] Figure 4 is a cross-sectional view showing the schematic configuration of the second die included in the press apparatus shown in Figure 1. [Figure 5] Figure 5 is a magnified view of the second mold shown in Figure 4. [Figure 6] Figure 6 is a cross-sectional view showing the schematic configuration of the third die included in the press apparatus shown in Figure 1. [Figure 7] Figure 7 is a cross-sectional view showing the schematic configuration of the fourth die included in the press apparatus shown in Figure 1. [Figure 8] Figure 8 is a schematic diagram illustrating the preparation steps in the manufacturing method of a press-formed product according to this embodiment. [Figure 9A]Figure 9A is a schematic diagram illustrating the deep drawing process, which is the first molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 9B] Figure 9B is a schematic diagram illustrating the deep drawing process, which is the first molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 9C] Figure 9C is a schematic diagram illustrating the deep drawing process, which is the first molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 9D] Figure 9D is a schematic diagram illustrating the deep drawing process, which is the first molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 10A] Figure 10A is a schematic diagram illustrating the gripping and bending process, which is the second molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 10B] Figure 10B is a schematic diagram illustrating the gripping and bending process, which is the second molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 10C] Figure 10C is a schematic diagram illustrating the gripping and bending process, which is the second molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 10D] Figure 10D is a schematic diagram illustrating the gripping and bending process, which is the second molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 10E] Figure 10E is a schematic diagram illustrating the gripping and bending process, which is the second molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 10F] Figure 10F is a schematic diagram illustrating the gripping and bending process, which is the second molding step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 11A] Figure 11A is a schematic diagram illustrating the third molding step, which is the punching step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 11B]Figure 11B is a schematic diagram illustrating the third molding step, which is the punching step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 12A] Figure 12A is a schematic diagram illustrating the fourth molding step, which is the piercing and bending step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 12B] Figure 12B is a schematic diagram illustrating the fourth molding step, which is the piercing and bending step, in the manufacturing method of a press-formed product according to this embodiment. [Figure 13] Figure 13 is a perspective view showing an example of a manufactured press-formed part. [Figure 14] Figure 14 is a cross-sectional view showing the schematic configuration of a second mold, which is different from the second mold shown in Figures 4 and 5. [Figure 15] Figure 15 is a schematic diagram used to explain the effect of the first mold shown in Figures 2 and 3. [Figure 16A] Figure 16A is a schematic diagram used to explain the effect of the first mold shown in Figures 2 and 3. [Figure 16B] Figure 16B is a schematic diagram used to explain the effect of the first mold shown in Figures 2 and 3. [Modes for carrying out the invention]

[0015] The inventors first conducted a frontal collision analysis (CAE analysis) of an automobile to verify the collision characteristics of a front floor in which the floor tunnel and floor sides are integrated. The solver used was JSOL's NSafe, which is based on ANSYS's LS-DYNA ver971. NSafe is a solver that can take into account spot welds and material fracture phenomena.

[0016] The CAE analysis evaluated the collision characteristics when a car body was hit head-on by a 254 mm diameter pole at a speed of 64 km / h. The collision characteristics were evaluated using the intrusion amount of the impacting object. Here, intrusion amount is the change in distance from the front end to the rear end of the front floor before and after the collision. The front end of the front floor was positioned at the same location as the brake pedal on the center line of the floor tunnel's top plate, and the rear end of the front floor was positioned at the very rear on the center line of the floor tunnel's top plate. A smaller intrusion amount indicates better collision characteristics.

[0017] As CAE models, we used comparative models 1 and 2, in which the floor tunnel is spot-welded to the left and right floor sides, and model 3, which simulates a tailor-welded blank (TWB) and integrates the floor tunnel with the left and right floor sides. Model 2 has a lighter structure with smaller plate thicknesses for the floor tunnel and floor sides compared to model 1. Model 3 has the same plate thickness for the floor tunnel and floor sides as model 2. The strength of the floor tunnel and floor sides is common to models 1 to 3. In each model, the plate thickness and strength of the floor tunnel are greater than the plate thickness and strength of the floor sides.

[0018] The results of this analysis showed that Model 1 had less penetration and better collision characteristics compared to Model 2. However, Model 1 had a larger plate thickness and heavier weight compared to Model 2. Despite having a smaller plate thickness and lighter weight compared to Model 1, Model 3 had less penetration and the best collision characteristics compared to Model 1. A detailed examination of the analysis results revealed that in Models 1 and 2, where the floor tunnel and floor side were joined by spot welding, delamination of the floor tunnel and floor side occurred at the spot welds during collision deformation, increasing the amount of penetration. On the other hand, in Model 3, which simulated a TWB and integrated the floor tunnel and floor side, no delamination of the floor tunnel and floor side occurred. Therefore, it is considered that delamination of the floor tunnel and floor side during collision deformation is the main cause of the decrease in collision characteristics.

[0019] In this way, integrating the floor tunnel and floor sides improves the collision characteristics of the front floor and reduces its weight. However, if the floor tunnel and floor sides are integrated from the material stage, the structural characteristics of the front floor make it difficult to mold.

[0020] For example, in a typical front floor, the vertical wall height of the floor tunnel is greater than that of other automotive structural components such as the side sills (rockers), B-pillars (center pillars), A-pillars (front pillars), and front side members. The taller the vertical wall, the greater the amount of processing required for the material, making it more prone to cracking during press forming.

[0021] The height of the longitudinal walls of the floor tunnel typically differs between the front and rear of the vehicle body. In this case, during press forming, the difference in height of the longitudinal walls in the longitudinal direction of the vehicle body can impart unnecessary tensile or compressive stress to the top plate and longitudinal walls of the floor tunnel. As a result, cracks or wrinkles may occur in the top plate and longitudinal walls of the floor tunnel.

[0022] When the floor tunnel and floor side are integrated, the length of the flange forming the floor side in the lateral direction of the vehicle body becomes considerably larger compared to the flange of a typical structural component. This flange may be given an uneven shape, for example, to ensure rigidity for supporting a car seat. In this case, during press forming, the difference in wire length between the uneven portion and the nearby flat portion makes it easy for wrinkles to occur in and around the uneven portion of the flange. In other words, during press forming, the wire length near the uneven portion tends to stretch in accordance with the uneven shape, but at the bottom dead center, the wire length in the flat portion near the uneven portion is excessive, making it easy for wrinkles to occur.

[0023] Tailored blanks are formed by joining the ends of multiple metal sheets together, for example, by laser welding, plasma welding, or mash seam welding. In such tailored blanks, the formability (deformability) of the weld line, i.e., the boundary between the metal sheets, is smaller compared to other areas. When using tailored blanks as a material for the front floor, cracks may occur at the boundary between the metal sheets where the deformability is low during press forming.

[0024] When using a tailored blank in press forming of the front floor, the metal sheet corresponding to the floor tunnel and the metal sheets corresponding to the left and right floor sides can have different thicknesses and strengths. For example, the metal sheet corresponding to the floor tunnel may have greater thickness and strength than the metal sheets corresponding to each floor side. Alternatively, the metal sheet corresponding to the floor tunnel may have greater thickness and strength than the metal sheets corresponding to each floor side, while the other thickness and strength are the same. During press forming, material flows from the left and right front sides to the central floor tunnel, but the amount of material flowing in may differ on the left and right sides. Therefore, the position of the boundary between the metal sheets of the tailored blank may not coincide on the left and right sides.

[0025] Thus, due to the structural characteristics of the front floor, it is difficult to mold the front floor with the floor tunnel and floor sides integrated from the material stage. Therefore, the inventors conducted extensive research and devised a press device capable of manufacturing special press-molded products, such as the front floor of an automobile, with good moldability.

[0026] The press apparatus according to the embodiment comprises a first die and a second die. The first die includes a first punch, a first die, and a first holder. The second die includes a second punch, a first pad, a second die, and a second holder. The first punch includes a first punch top surface, a first punch shoulder, a first punch side surface, a first punch base, and a first punch flange surface. The first punch shoulder is continuous with the first punch top surface. The first punch side surface is continuous with the first punch shoulder. The first punch side surface has a height difference in the longitudinal direction of the first die. The first punch base is continuous with the first punch side surface on the opposite side of the first punch shoulder. The first punch flange surface is continuous with the first punch base. The first punch flange surface extends outward from the first punch base in the width direction of the first die. The first die includes a first die bottom surface, a first die bottom edge, a first die side surface, a first die shoulder, and a first die flange surface. The first die bottom surface has a shape corresponding to the first punch top surface. The first die bottom surface faces the first punch top surface. The first die bottom edge is continuous with the first die bottom surface. The first die bottom edge has a shape corresponding to the first punch shoulder. The first die side surface is continuous with the first die bottom edge. The first die side surface has a shape corresponding to the first punch side surface. The first die shoulder is continuous with the first die side surface on the opposite side of the first die bottom edge. The first die shoulder has a shape corresponding to the first punch base. The first die flange surface is continuous with the first die shoulder. The first die flange surface extends outward from the first die shoulder in the width direction of the first mold. The first die flange surface faces the first punch flange surface and the first holder. The second punch includes a second punch top surface, a second punch shoulder, a second punch side surface, a second punch base, and a second punch flange surface. The second punch top surface faces the first pad. The second punch shoulder is continuous with the second punch top surface. The second punch side surface is continuous with the second punch shoulder. The second punch base is continuous with the second punch side surface on the opposite side of the second punch shoulder. The second punch flange surface is continuous with the second punch base. The second punch flange surface extends outward from the second punch base in the width direction of the second die. The second punch flange surface has an uneven shape on at least a portion of it. The second die includes a second die bottom edge, a second die side surface, a second die shoulder, and a second die flange surface. The second die bottom edge has a shape corresponding to the second punch shoulder.The second die side surface is continuous with the second die bottom edge. The second die side surface has a shape corresponding to the second punch side surface. The second die shoulder is continuous with the second die side surface on the opposite side of the second die bottom edge. The second die shoulder has a shape corresponding to the second punch base. The second die flange surface is continuous with the second die shoulder. The second die flange surface extends outward from the second die shoulder in the width direction of the second die. The second die flange surface faces the second punch flange surface and the second holder. At the top dead center of the second die, the end of the second holder on the second die flange surface side is located between the second punch shoulder and the second punch flange surface in the pressing direction of the second die (first configuration).

[0027] The press apparatus according to the first configuration is used to manufacture a press-formed product, such as the front floor of an automobile, from a single sheet of material. In the manufacture of the press-formed product, a deep drawing process can be performed using the first die, followed by a gripping and bending process using the second die.

[0028] In the deep drawing process using the first die, the material is held between the first die flange surface and the first holder, and the first die is brought relatively close to the first punch. The material is then pressed between the first punch and the first die to form the top plate, vertical walls, and flange. In the deep drawing process using the first die, tension can be applied to the parts of the material that will become the top plate and vertical walls by holding the material between the first die flange surface and the first holder from the beginning of the forming process. This suppresses the occurrence of wrinkles in the top plate and vertical walls, even when the height of the vertical walls changes in the longitudinal direction. Furthermore, even when forming a top plate with, for example, recessed sections, the material can be sufficiently pressed between the top surface of the first punch and the bottom surface of the first die, which has a shape corresponding to the top surface of the first punch, allowing for the precise forming of the top plate.

[0029] The gripping and bending process using the second die is performed using the intermediate molded product obtained in the deep drawing process using the first die as the material. In the gripping and bending process using the second die, the top plate of the intermediate molded product (first process product) is held between the top surface of the second punch and the first pad, and the second die is brought relatively close to the second punch and the second holder. In the initial state, i.e., at the top dead center of the second die, the end of the second holder on the second die flange side is positioned between the second punch shoulder and the second punch flange surface in the pressing direction. At the completion of molding, i.e., at the bottom dead center of the second die, the end of the second holder on the second die flange side is positioned at the same position as the punch flange surface in the pressing direction. As a result, the second holder can grip the flange of the intermediate molded product between itself and the second die flange surface from the middle of the molding process and continuously apply tension to the flange until the molding is complete. Therefore, even when a second mold is used to create an uneven shape on the flange, the tension applied during press forming makes it difficult for the wire length to stretch in the flat areas near the uneven parts due to the uneven shape, thus reducing wrinkles. In this way, an uneven portion can be formed on the flange while suppressing the occurrence of wrinkles.

[0030] In the gripping and bending process using the second die, the second holder begins gripping the flange of the intermediate molded product together with the second die flange surface not at the beginning of the molding process, but midway through. Therefore, excessive tension is not applied to the flange, and cracking can be suppressed in and around the uneven parts of the flange. Furthermore, when a tailored blank is used as the material, molding can be performed while applying appropriate tension to the flange, which can suppress cracking at the boundaries between metal plates and misalignment at the boundaries between metal plates. In addition, excessive tension is not applied to the vertical walls continuous with the flange, so even if the height of the vertical walls is relatively large, cracking of the vertical walls and deterioration of dimensional accuracy can be suppressed.

[0031] Thus, with the press apparatus according to the first configuration, even press-formed products with special structures can be formed while suppressing the occurrence of cracks and wrinkles. In other words, the press apparatus according to the first configuration can manufacture press-formed products such as the front floor of an automobile with good formability.

[0032] At the top dead center of the second die, the end of the second holder on the second die flange side may be located in the range where the second punch base exists in the pressing direction (second configuration).

[0033] In a press apparatus relating to the first or second configuration, the second holder may include a bead. The bead is formed on the surface of the second holder on the second die flange side (third configuration).

[0034] In the third configuration, a bead is formed on the surface of the second die flange side of the second holder included in the second mold. In this case, during the gripping and bending process by the second mold, the flange of the intermediate molded product catches on the bead of the second holder, making it easier to apply tension to the flange. This makes it possible to further suppress the occurrence of wrinkles in and around the uneven parts of the flange during the gripping and bending process by the second mold.

[0035] In a press apparatus relating to the first or second configuration, the first holder may include a bead. The bead is formed on the surface of the first holder on the side of the first die flange (fourth configuration).

[0036] In the fourth configuration, a bead is formed on the surface of the first die flange side of the first holder included in the first mold. In this case, when the material is clamped between the first die flange surface and the first holder during the deep drawing process using the first mold, the bead of the first holder can form a bead portion on the material and apply tension. This makes it less likely for wrinkles to occur on the top plate and vertical walls, even when the vertical wall height changes in the longitudinal direction. Furthermore, because more tension can be applied to the material, when a tailored blank is used as the material, misalignment at the boundary between metal plates can be further suppressed.

[0037] In the press apparatus according to the first or second configuration, the first holder may include a first bead. In this case, the second holder may include a second bead. The first bead is formed on the surface of the first holder facing the first die flange. The second bead is formed on the surface of the second holder facing the second die flange. When the first die is viewed in cross-section, the line length along the surface of the first punch and the surface of the first holder from the center of the first punch in the width direction of the first die to the first bead is preferably equal to the line length along the surface of the second punch and the surface of the second holder from the center of the second punch in the width direction of the second die to the second bead (fifth configuration).

[0038] In the fifth configuration, beads are provided on both the first holder included in the first mold and the second holder included in the second mold. The position of the first bead on the first holder coincides with the position of the second bead on the second holder. That is, in a cross-sectional view of the first mold, the linear length along the surface of the first punch and first holder from the width center of the first punch to the first bead is substantially equal to the linear length along the surface of the second punch and second holder from the width center of the second punch to the second bead in a cross-sectional view of the second mold. In this case, when the intermediate molded product obtained in the deep drawing process using the first mold is placed in the second mold, the bead portion formed on the flange by the first bead of the first holder can be positioned on the second bead of the second holder. This makes it easier for the flange of the intermediate molded product to catch on the bead of the second holder in the gripping and bending process using the second mold, thus making it easier to apply more tension to the flange. Furthermore, it is possible to prevent the bead portion of the flange from being pressed and deformed by the second holder in the gripping and bending process using the second mold. Therefore, no extra tension is applied to the flange due to deformation of the bead. Consequently, when a tailored blank is used as the material, the occurrence of cracks at the boundary between metal plates can be further suppressed.

[0039] In a press apparatus according to any of the first to fifth configurations, when viewing the first die in cross-section, the linear length of the surface of the first punch from the center of the first punch in the width direction of the first die to the end of the first punch base on the first punch flange side is preferably equal to the linear length of the surface of the second punch from the center of the second punch in the width direction of the second die to the end of the second punch base on the second punch flange side when viewing the second die in cross-section (sixth configuration).

[0040] In the sixth configuration, the linear length of the surface of the first punch from the width center of the first punch to the end of the base of the first punch in a cross-sectional view of the first die is substantially equal to the linear length of the surface of the second punch from the width center of the second punch to the end of the base of the second punch in a cross-sectional view of the second die. This makes it difficult for material to flow from the flange surface side of the second punch to the base and side of the second punch, and for material to flow from the base and side of the second punch to the flange surface side, when the grip bending process is performed by the second die after the deep drawing process by the first die. As a result, changes in stress due to material inflow or outflow are suppressed in the vertical walls of the intermediate molded product and at the connection points between the vertical walls and the flange. Thus, the dimensional accuracy of the press-formed product obtained in the grip bending process can be ensured. Furthermore, by suppressing the inflow of material into the flange and the outflow of material from the flange, displacement of the intermediate molded product, which is the material for the grip bending process, is less likely to occur. Therefore, it is possible to prevent indentations from remaining on the second punch flange surface and the second die flange surface, as well as wrinkles, in and around the uneven parts of the flange. Furthermore, when a tailored blank is used as the material, the boundary between the metal sheets does not substantially move from its position in the deep drawing process by the first die during the gripping and bending process by the second die, thus suppressing cracking at the boundary between the metal sheets.

[0041] For example, in press-formed parts with flanges that are long in the left-right direction of the vehicle, such as the front floor of an automobile, even a slight dimensional change at the end of the flange on the vertical wall side during press forming can significantly affect the dimensional accuracy at the end of the flange on the opposite side of the vertical wall, degrading the overall dimensional accuracy of the press-formed part. In contrast, in the sixth configuration, by making the linear length of the surface of the second punch from the width center of the second punch to the end of the base of the second punch substantially the same as the linear length of the surface of the first punch from the width center of the first punch to the end of the base of the first punch, the material can be bent by the base of the second punch and the corresponding second die shoulder at the same position as during the deep drawing process using the first die during the gripping and bending process using the second die. In this case, unnecessary tensile or compressive deformation of the intermediate molded product as material is less likely to occur at and near the second die shoulder. Therefore, dimensional changes of the flange near the second die shoulder can be suppressed. As a result, the opening or closing of the flange in the press-formed part after demolding is suppressed. Furthermore, wall opening or closing of the press-formed part can also be suppressed. Therefore, the dimensional accuracy of press-formed products can be improved.

[0042] In a press apparatus according to any of the first to sixth configurations, when the first die is viewed in cross-section, the first die flange surface may be inclined with respect to the horizontal plane such that, in the width direction of the first die, the inner end is located closer to the first die bottom surface in the pressing direction of the first die than the outer end (seventh configuration).

[0043] In the seventh configuration, the first die flange surface is inclined to slope downwards as it moves outward in the width direction from the first die shoulder side, allowing the first die shoulder to be formed gently. In this case, during the deep drawing process using the first die, when material flows from the first die flange surface side through the first die shoulder to the first die side side, the inflow resistance at the first die shoulder is reduced. As a result, deformation of the material at and near the first die shoulder is reduced, and cracking of the vertical wall in the intermediate molded product obtained in the deep drawing process can be suppressed. Furthermore, when a tailored blank is used as the material, cracking at the boundary between metal plates can be suppressed.

[0044] In the deep drawing process, when the material on the flange side passes through the die shoulder and flows into the vertical wall side, bending and unbending deformation of the material occurs at and near the die shoulder. If the amount of bending and unbending deformation is large, wall warping occurs in the resulting intermediate molded product. In contrast, in the seventh configuration, the first die shoulder is gently formed by inclining the first die flange surface with respect to the horizontal plane. As a result, the amount of bending and unbending deformation when the material passes through the first die shoulder is reduced, and wall warping of the intermediate molded product obtained in the deep drawing process can be suppressed.

[0045] In a press apparatus according to any of the first to seventh configurations, the side surface of the first punch may include a bulge. The bulge extends outward in the width direction of the first die (eighth configuration).

[0046] In the eighth configuration, a bulge is provided on the side surface of the first punch. The bulge is outward in the width direction of the first die, that is, in the opposite direction to the wall warping that is likely to occur in the deep drawing process. As a result, during the deep drawing process using the first die, the bulge on the side surface of the first punch causes the vertical wall to bulge in the opposite direction to the wall warping, thereby suppressing wall warping of the intermediate molded product. In other words, when the intermediate molded product is removed from the first die, if the vertical wall that has bulged outward on the outside of the intermediate molded product attempts to deform by warping inward, the deformation of the wall warping is canceled out by the bulge of the vertical wall. Therefore, it is possible to obtain a vertical wall with no or minimal wall warping.

[0047] In a press apparatus relating to any of the first to eighth configurations, the length of the first punch top surface in the width direction of the first die may be greater than the length of the second punch top surface in the width direction of the second die (ninth configuration).

[0048] In the ninth configuration, the width of the top surface of the first punch in the first mold is greater than the width of the top surface of the second punch in the second mold. In this case, when the intermediate molded product obtained in the deep drawing process using the first mold is placed in the second mold, the ridge portion connecting the top plate and the vertical wall of the intermediate molded product will be located outside the shoulder of the second punch in the width direction of the second mold. In the gripping and bending process using the second mold, the ridge portion is bent back near the shoulder of the second punch by the second punch and the second die. In the bent portion, tensile stress is generated on the inside (second punch side) of the intermediate molded product, and compressive stress is generated on the outside (second die side) of the intermediate molded product. On the other hand, at the position of the second punch shoulder, compressive stress is generated on the inside of the intermediate molded product and tensile stress is generated on the outside of the intermediate molded product due to bending by the second punch shoulder. When a press-formed product formed in the gripping and bending process is removed from the second die, a wall-opening moment is generated due to the reversal stress in the portion bent by the second punch shoulder. However, a wall-closing moment is generated due to the reversal stress in the ridge portion that is bent back near the second punch shoulder, and the wall-closing moment cancels out the wall-opening moment. Therefore, the wall-opening moment is reduced, and the springback of the wall opening in the press-formed product is reduced.

[0049] In a press apparatus according to any of the first to ninth configurations, the top surface of the first punch may include a convex surface. The convex surface is positioned, for example, adjacent to the shoulder of the first punch. The convex surface protrudes outward from the first punch (tenth configuration).

[0050] In the tenth configuration, a convex surface is provided near the shoulder of the first punch on the top surface of the first punch of the first die. In the gripping and bending process by the second die, the convex portion formed by the convex surface on the top surface of the first punch is bent back near the shoulder of the second punch by the second punch and the second die. In the bent portion, tensile stress is generated on the inside (second punch side) of the intermediate molded product, and compressive stress is generated on the outside (second die side) of the intermediate molded product. On the other hand, at the position of the second punch shoulder, compressive stress is generated on the inside of the intermediate molded product and tensile stress is generated on the outside of the intermediate molded product as the material is bent by the second punch shoulder. When the press-formed product formed in the gripping and bending process is removed from the second die, a wall-opening moment is generated by the reversal stress of the portion bent by the second punch shoulder, but a wall-closing moment is generated by the reversal stress of the convex portion bent back near the second punch shoulder, and the wall-closing moment cancels out the wall-opening moment. Therefore, the wall-opening moment is reduced, and the springback of the wall-opening is reduced in the press-formed product.

[0051] In a press apparatus according to any of the first to tenth configurations, the second die flange surface may include a convex or concave surface. A convex surface is, for example, positioned adjacent to the second die shoulder and protruding outward from the second die. A concave surface is, for example, positioned adjacent to the second die shoulder and recessed inward from the second die (eleventh configuration).

[0052] In the 11th configuration, a convex or concave surface adjacent to the second die shoulder is provided on the second die flange surface of the second mold. In this case, during the gripping and bending process by the second mold, a recess or convex portion is formed in the press-formed product by the convex or concave surface near the second die shoulder. For example, if the recess formed by the convex surface of the second die flange surface is bent back in the next step after the gripping and bending process, tensile stress is generated on the outside of the press-formed product and compressive stress is generated on the inside of the press-formed product in the bent portion. This can generate a moment in the direction that closes the flange of the press-formed product (upward). On the other hand, if the convex portion formed by the concave surface of the second die flange surface is bent back in the next step after the gripping and bending process, compressive stress is generated on the outside of the press-formed product and tensile stress is generated on the inside of the press-formed product in the bent portion. This can generate a moment in the direction that opens the flange of the press-formed product (downward). In this way, the opening and closing of the flange can be adjusted by generating a moment in the direction that opens or closes the flange.

[0053] In a press apparatus according to any of the first to eleventh configurations, the side surface of the second punch may include a bulge. The bulge extends outward in the width direction of the second die (twelfth configuration).

[0054] In the 12th configuration, a bulge is provided on the side surface of the second punch. The bulge is outward in the width direction of the second die, that is, in the opposite direction to the wall warping that may occur in the deep drawing process by the first die and the gripping and bending process by the second die. In the gripping and bending process by the second die, the bulge on the side surface of the second punch can cause the vertical wall to bulge in the opposite direction to the wall warping. In this case, when the press-formed product is removed from the second die, if the vertical wall that has bulged outward on the press-formed product attempts to deform by warping inward, the deformation of the wall warping is canceled out by the bulge of the vertical wall. Therefore, wall warping can be reduced. If bulging remains on the vertical wall of the press-formed product after it has been removed from the second die, the bulged vertical wall can be bent back in the next step after the gripping and bending process. This reduces wall opening and wall warping.

[0055] In a press apparatus according to any of the first to twelfth configurations, a step may be provided on the shoulder side of the first die flange surface. The step is provided on the first die flange surface such that the clearance between the first punch and the first die is larger on the inside of the step than on the outside of the step in the width direction of the first die. When the first die is viewed in cross-section, it is preferable that the linear length of the surface of the first punch from the center of the first punch in the width direction of the first die to the boundary between the first punch and the first holder is greater than or equal to the linear length of the surface of the first die from the center of the first die in the width direction of the first die to the step (thirteenth configuration).

[0056] When manufacturing a press-formed product using a tailored blank as the material, where the thickness of the top plate and vertical walls is greater than the thickness of the flange, the first die is provided with a step to accommodate the difference in material thickness. This step can be formed, for example, on the shoulder side of the first die on the first die flange surface. In the 13th configuration, the linear length of the surface of the first punch from the width center of the first punch to the boundary between the first punch and the first holder is greater than or equal to the linear length of the surface of the first die from the width center of the first die to the step. In this case, the material can be firmly held between the first die flange surface and the first holder during the deep drawing process by the first die, and at the bottom dead center of forming, the entire material can be held between the first punch, the first die, and the first holder. This makes it possible to suppress the occurrence of wrinkles in the intermediate molded product obtained in the deep drawing process.

[0057] A press apparatus according to any of the first to thirteenth configurations may further include a third die. The third die includes a third punch, a second pad, and a third die. The third punch includes a third punch top surface, a third punch shoulder, a third punch side surface, a third punch base, and a third punch flange surface. The third punch shoulder is continuous with the third punch top surface. The third punch side surface is continuous with the third punch shoulder. The third punch base is continuous with the third punch side surface on the opposite side of the third punch shoulder. The third punch flange surface is continuous with the third punch base. The third punch flange surface extends outward from the third punch base in the width direction of the third die. The second pad includes a pad bottom surface, a pad bottom edge, a pad side surface, a pad shoulder, and a pad flange surface. The pad bottom surface has a shape corresponding to the third punch top surface. The pad bottom surface faces the third punch top surface. The pad bottom edge is continuous with the pad bottom surface. The bottom edge of the pad has a shape corresponding to the shoulder of the third punch. The side of the pad is continuous with the bottom edge of the pad. The side of the pad has a shape corresponding to the side of the third punch. The pad shoulder is continuous with the side of the pad on the opposite side of the bottom edge of the pad. The pad shoulder has a shape corresponding to the base of the third punch. The pad flange surface is continuous with the pad shoulder. The pad flange surface extends outward from the pad shoulder in the width direction of the third die. The pad flange surface faces the third punch flange surface. The third die is positioned outside the third punch and the second pad in the width direction of the third die (configuration 14).

[0058] In the press apparatus according to the 14th configuration, when the second die is viewed in cross-section, the linear length of the surface of the second punch from the center of the second punch in the width direction of the second die to the end of the second punch base on the second punch flange side may be equal to the linear length of the surface of the third punch from the center of the third punch in the width direction of the third die to the end of the third punch base on the third punch flange side, when the third die is viewed in cross-section (15th configuration).

[0059] In the 15th configuration, the linear length of the surface of the third punch from the width center of the third punch to the end of the base of the third punch is substantially the same as the linear length of the surface of the second punch from the width center of the second punch to the end of the base of the second punch. This makes it difficult for material to flow from the third punch flange surface to the third punch base and third punch side, and for material to flow from the third punch base and third punch side to the third punch flange surface, when the process using the third die is performed. As a result, changes in stress caused by material inflow or outflow are suppressed in the parts of the press-formed product that are pressed against the side of the third punch and the parts that are pressed against the base of the third punch. Thus, deterioration of the dimensional accuracy of the press-formed product can be prevented. Furthermore, when a tailored blank is used as the material, when the molded product is held by the third punch and the second pad, the boundary between the metal plates does not substantially move from its position in the gripping and bending process by the second die, thus suppressing cracking at the boundary between the metal plates.

[0060] A press apparatus relating to the 14th or 15th configuration may further include a fourth die. The fourth die includes a fourth punch, a third holder, and a fourth die. The third holder includes a holder top surface, a holder shoulder, a holder side surface, a holder base, and a holder flange surface. The holder shoulder is continuous with the holder top surface. The holder side surface is continuous with the holder shoulder. The holder base is continuous with the holder side surface on the opposite side of the holder shoulder. The holder flange surface is continuous with the holder base. The holder flange surface extends outward from the holder base in the width direction of the fourth die. The fourth die includes a fourth die bottom surface, a fourth die bottom edge, a fourth die side surface, a fourth die shoulder, and a fourth die flange surface. The fourth die bottom surface has a shape corresponding to the holder top surface. The fourth die bottom surface faces the holder top surface. The fourth die bottom edge is continuous with the fourth die bottom surface. The bottom edge of the fourth die has a shape corresponding to the holder shoulder. The side surface of the fourth die is continuous with the bottom edge of the fourth die. The side surface of the fourth die has a shape corresponding to the side surface of the holder. The shoulder of the fourth die is continuous with the side surface of the fourth die on the opposite side of the bottom edge of the fourth die. The shoulder of the fourth die has a shape corresponding to the base of the holder. The flange surface of the fourth die is continuous with the shoulder of the fourth die. The flange surface of the fourth die extends outward from the shoulder of the fourth die in the width direction of the fourth mold. The flange surface of the fourth die faces the flange surface of the holder. The fourth punch is positioned outside the third holder and the fourth die in the width direction of the fourth mold (configuration 16).

[0061] In the press apparatus according to the 16th configuration, when the second die is viewed in cross-section, the linear length of the surface of the second punch from the center of the second punch in the width direction of the second die to the end of the second punch base on the second punch flange side may be equal to the linear length of the surface of the third holder from the center of the third holder in the width direction of the fourth die to the end of the holder base on the holder flange side of the holder (17th configuration).

[0062] In the 17th configuration, the linear length of the surface of the third holder of the fourth die, from the width center of the third holder to the end of the holder base, is substantially matched with the linear length of the surface of the second punch, from the width center of the second punch to the end of the second punch base. This makes it difficult for material to flow from the holder flange surface to the holder base and holder side, and for material to flow from the holder base and holder side to the holder flange surface, when the process using the fourth die is performed. As a result, changes in stress caused by material inflow or outflow are suppressed in the parts of the press-formed product that are pressed against the holder side and the parts that are pressed against the holder base and the shoulder of the fourth die. Thus, deterioration of the dimensional accuracy of the press-formed product can be prevented. Furthermore, when a tailored blank is used as the material, the boundary between the metal sheets does not substantially move from the gripping and bending process using the second die to the process using the fourth die, so cracking at the boundary between the metal sheets can be suppressed.

[0063] A method for manufacturing a press-formed product according to an embodiment comprises the steps of: preparing a material including a plurality of metal plates joined together; a first step of press-forming the material into an intermediate molded product using a first die; and a second step of press-forming the intermediate molded product using a second die. The first die includes a first punch, a first die, and a first holder. The second die includes a second punch, a pad, a second die, and a second holder. The intermediate molded product includes a top plate, vertical walls, and flanges. The vertical walls are connected to the top plate. The vertical walls have height differences in the longitudinal direction of the intermediate molded product. The flanges are connected to the vertical walls on the opposite side of the top plate. The flanges extend outward from the vertical walls in the width direction of the intermediate molded product. The first step includes the step of clamping the material between the first die and the first holder, and the step of bringing the first punch and the first die relatively close together while the material is clamped between the first die and the first holder, and forming the top plate and vertical walls of the intermediate molded product with the first punch and the first die. The second step includes the steps of: clamping the top plate of the intermediate molded product with the second punch and the pad; bringing the second punch and the second die relatively close together while the top plate is clamped with the second punch and the pad, but the widthwise end of the intermediate molded product is not clamped with the second die and the second holder, and starting molding by the second punch and the second die; before the flange of the intermediate molded product is formed by the relatively close second punch and second die, the end of the intermediate molded product is clamped with the second die and the second holder; and forming the flange with the second punch and the second die while tension is applied to the flange by the end of the intermediate molded product being clamped with the second die and the second holder, thereby forming an uneven shape on the flange (configuration of the 18th).

[0064] In the second step, it is preferable that the end of the intermediate molded product is held between the second die and the second holder immediately before the formation of the flange's uneven shape by the second punch and the second die begins (configuration 19).

[0065] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent components are denoted by the same reference numerals, and the same description will not be repeated.

[0066] [Pressing device] Figure 1 is a schematic diagram showing a press apparatus 100 for press-formed products according to this embodiment. The press apparatus 100 comprises a first die 10 and a second die 20. The press apparatus 100 further comprises a third die 30 and a fourth die 40. The press apparatus 100 is, for example, a single press apparatus (transfer press apparatus) to which dies 10, 20, 30, and 40 are attached. However, the press apparatus 100 may be a tandem press line in which dies 10, 20, 30, and 40 are each attached to separate press apparatuses. Alternatively, the press apparatus 100 may be composed of a combination of a transfer press apparatus and a tandem press line. For example, dies 10 and 20 may be attached to a transfer press apparatus, and dies 30 and 40 may be attached to a tandem press line. The dies 10, 20, 30, and 40 will be described below.

[0067] [First mold] Figure 2 is a cross-sectional view showing the schematic configuration of the first mold 10. As shown in Figure 2, the first mold 10 includes a punch 11, a die 12, and a holder 13. The punch 11, die 12, and holder 13 extend in a direction intersecting the plane of paper in Figure 2. For the sake of explanation, the direction in which the punch 11, die 12, and holder 13 extend will be referred to as the longitudinal direction of the first mold 10, and the vertical direction in the plane of paper in Figure 2 will be referred to as the vertical direction or height direction of the first mold 10. In addition, the direction perpendicular to the plane consisting of the longitudinal direction and the vertical direction will be referred to as the left-right direction or width direction of the first mold 10. The cross-section of the first mold 10 is the cross-section of the first mold 10 when cut by a plane perpendicular to the longitudinal direction. Figure 3 is a partially enlarged view of the first mold 10 shown in Figure 2.

[0068] Referring to Figures 2 and 3, the punch 11 includes a punch top surface 111, a punch shoulder 112, a punch side surface 113, a punch base 114, and a punch flange surface 115.

[0069] The punch top surface 111 extends in the width direction of the first die 10 in a cross-sectional view of the first die 10. The punch top surface 111 has a length (width) W in the width direction of the first die 10. pt1It has the following. In the example shown in Figure 2, a groove 111a is formed on the punch top surface 111. The groove 111a extends in the longitudinal direction of the first die 10. The groove 111a may extend over the entire punch top surface 111 in the longitudinal direction of the first die 10, or it may be provided on a part of the punch top surface 111.

[0070] To the left and right of the punch top surface 111 are a punch shoulder 112, a punch side surface 113, a punch base 114, and a punch flange surface 115, respectively. The punch top surface 111 may include a convex surface 111b near the punch shoulder 112. The convex surface 111b is located on the portion of the punch top surface 111 adjacent to the punch shoulder 112. The convex surface 111b protrudes outward from the punch 11 compared to the other portions of the punch top surface 111. More specifically, the convex surface 111b protrudes upward compared to the other portions of the punch top surface 111.

[0071] The punch shoulder 112 is continuous with the punch top surface 111. More specifically, the punch shoulder 112 is provided continuously on the left and right side edges of the punch top surface 111. The punch shoulder 112 may also be continuous with the convex surface 111b of the punch top surface 111. The punch shoulder 112 has a substantially arc shape in a cross-sectional view of the first die 10, for example. In this embodiment, substantially arc shape is a concept that includes not only curves that constitute part of a perfect circle, but also smooth curves such as elliptic curves and spline curves.

[0072] The punch side 113 is continuous with the punch shoulder 112. In a cross-sectional view of the first die 10, the punch side 113 extends downward from the punch shoulder 112. The punch side 113 may include a bulge 113a. The bulge 113a is the portion of the punch side 113 that bulges outward in the width direction of the first die 10. The bulge 113a has, for example, a curved shape that is convex outward in the width direction in a cross-sectional view of the first die 10. Preferably, the bulge 113a is formed on the punch side 113 such that the portion from its top to the punch base 114 does not have a downward angle in a cross-sectional view of the first die 10. Preferably, the bulge 113a is smoothly connected to the other portion of the punch side 113 via a curve in a cross-sectional view of the first die 10.

[0073] The punch side surface 113 has a height difference in the longitudinal direction of the first die 10. For example, the length (height) H of the punch side surface 113 in the vertical direction. ps1 The height H of the punch side 113 is greater on one side in the longitudinal direction of the first mold 10 and smaller on the other side. ps1 The height H of the punch side surface 113 in this embodiment may change gradually along the longitudinal direction of the first mold 10, or it may change in a stepped manner. ps1 This height includes the punch top surface 111, the punch shoulder 112, and the punch base 114. That is, in the cross-section of the first die 10, the distance from the end of the punch base 114 on the punch flange surface 115 side to the highest position in the height direction of the punch top surface 111 is the height H of the punch side surface 113. ps1 Let's assume the height is H. ps1 This is the maximum distance in the height direction from the end of the punch base 114 on the punch flange surface 115 side to the punch top surface 111, as viewed in cross-section of the first mold 10. The height H of the punch side surface 113. ps1 This value is not constant along the entire length of the first mold 10, but varies along the longitudinal direction of the first mold 10.

[0074] The punch base 114 is continuous with the punch side 113 on the opposite side of the punch shoulder 112. The punch base 114 is provided continuously with the lower end of the punch side 113.

[0075] The punch flange surface 115 is continuous with the punch base 114. In a cross-sectional view of the first die 10, the punch flange surface 115 extends outward from the punch base 114 in the width direction of the first die 10. Preferably, in a cross-sectional view of the first die 10, the punch flange surface 115 is inclined with respect to the horizontal plane. The horizontal plane is a plane perpendicular to the vertical direction, and when the horizontal plane is projected onto the cross-section of the first die 10, it becomes a straight line in the width direction. In this embodiment, the punch flange surface 115 slopes downward as it moves outward in the width direction of the first die 10.

[0076] In a cross-sectional view of the first mold 10, the left and right punch shoulders 112, punch side surfaces 113, punch base 114, and punch flange surfaces 115 may be symmetrical or asymmetrical with respect to the center line C1 in the width direction of the punch 11 and die 12. The center line C1 is typically an imaginary line that passes through the center of the punch top surface 111 and the die bottom surface 121 (described later) in the width direction of the first mold 10 and extends in the height direction of the first mold 10.

[0077] The die 12 includes a die bottom surface 121, a die bottom edge 122, a die side surface 123, a die shoulder 124, and a die flange surface 125.

[0078] The die bottom surface 121 faces the punch top surface 111. The die bottom surface 121 has a shape corresponding to the punch top surface 111. In this embodiment, the die bottom surface 121 has a convex portion 121a corresponding to the concave portion 111a of the punch top surface 111.

[0079] The die bottom surface 121 is flanked by die bottom edges 122, die sides 123, die shoulders 124, and die flange surfaces 125. The die bottom surface 121 includes a concave surface 121b near the die bottom edge 122, corresponding to the convex surface 111b of the punch top surface 111. The concave surface 121b is positioned to correspond to the convex surface 111b of the punch top surface 111 and has a shape corresponding to the convex surface 111b. The concave surface 121b is located in the portion of the die bottom surface 121 adjacent to the die bottom edge 122. The concave surface 121b is recessed inward compared to the other parts of the die bottom surface 121. More specifically, the concave surface 121b is recessed upward compared to the other parts of the die bottom surface 121.

[0080] The die bottom edge 122 is continuous with the die bottom surface 121. More specifically, the die bottom edge 122 is provided continuously with the left and right side edges of the die bottom surface 121. The die bottom edge 122 may also be continuous with the concave surface 121b of the die bottom surface 121. The die bottom edge 122 has a shape corresponding to the punch shoulder 112. The die bottom edge 122 may, for example, have a substantially arc shape in a cross-sectional view of the first die 10.

[0081] The die side 123 is continuous with the die bottom edge 122. In a cross-sectional view of the first mold 10, the die side 123 extends downward from the die bottom edge 122. The die side 123 has a shape corresponding to the punch side 113. The die side 123 corresponds to the punch side 113 and has a height difference in the longitudinal direction of the first mold 10. In this embodiment, the die side 123 includes a recessed portion 123a corresponding to the bulge 113a of the punch side 113. The recessed portion 123a is the portion of the die side 123 that is recessed outward in the width direction of the first mold 10. The recessed portion 123a has, for example, a concave curved shape outward in the width direction in a cross-sectional view of the first mold 10. Preferably, the recessed portion 123a is smoothly connected to the other portion of the die side 123 via a curve in a cross-sectional view of the first mold 10.

[0082] The die shoulder 124 is continuous with the die side surface 123 on the opposite side of the die bottom edge 122. The die shoulder 124 is provided continuously with the lower end of the die side surface 123. The die shoulder 124 has a shape corresponding to the punch base 114. Like the punch base 114, the die shoulder 124 has a substantially arc shape in a cross-sectional view of the first mold 10, for example. The radius of curvature of the die shoulder 124 is preferably 25.0 mm or more. The radius of curvature of the die shoulder 124 may be 125.0 mm or less. If the die shoulder 124 is composed of a smooth curve other than a curve that constitutes part of a perfect circle, such as an elliptic curve or a spline curve, in the cross-section of the first mold 10, the radius of curvature of the die shoulder 124 shall be defined as the radius of the circle passing through the two ends of the curve and the midpoint of the curve.

[0083] The die flange surface 125 is continuous with the die shoulder 124. In a cross-sectional view of the first mold 10, the die flange surface 125 extends outward from the die shoulder 124 in the width direction of the first mold 10. The die flange surface 125 is preferably inclined with respect to the horizontal plane in a cross-sectional view of the first mold 10, corresponding to the punch flange surface 115. In this embodiment, when the first mold 10 is viewed in cross-section, the die flange surface 125 is inclined with respect to the horizontal plane such that, in the width direction of the first mold 10, the inner end is located closer to the die bottom surface 121 than the outer end. That is, the die flange surface 125 slopes downward as it moves outward in the width direction of the first mold 10. In a cross-sectional view of the first mold 10, the angle α that the die flange surface 125 makes with respect to the horizontal plane (width direction) is preferably greater than 0° and 20° or less. However, the die flange surface 125 does not need to be inclined with respect to the horizontal plane in a cross-sectional view of the first mold 10 (α=0°).

[0084] The die flange surface 125 includes a step 125a. The step 125a is provided on the portion of the die flange surface 125 that is on the die shoulder 124 side. Due to the step 125a, the clearance between the punch 11 and the die 12 when the first mold 10 is closed is greater on the inside than on the outside in the width direction of the first mold 10.

[0085] In a cross-sectional view of the first mold 10, the width W of the die flange surface 125 df1 is the height H of the die side surface 123 ds1 as described above. In a cross-sectional view of the first mold 10, the width W of the die flange surface 125 df1 is the height H of the die side surface 123 ds1 and may be larger. The width W of the die flange surface 125 df1 is the length of the die flange surface 125 in the width direction of the first mold 10. The height H of the die side surface 123 ds1 is the height H of the punch side surface 113 ps1 and is defined similarly for the die bottom surface 121, the die bottom edge 122, and the die shoulder 124. That is, in a cross-sectional view of the first mold 10, the height H of the die side surface 123 is the distance from the end of the die shoulder 124 on the die flange surface 125 side to the highest position in the height direction of the die bottom surface 121 ds1 and is so defined. The height H ds1 is the maximum distance in the height direction from the end of the die shoulder 124 on the die flange surface 125 side to the die bottom surface 121 as seen in the cross-section of the first mold 10. The height H of the die side surface 123 ds1 is not constant over the entire length of the first mold 10 and varies along the longitudinal direction of the first mold 10.

[0086] The die flange surface 125 extends outward beyond the punch flange surface 115 in the width direction of the first mold 10. The die flange surface 125 faces the punch flange surface 115 and the holder 13.

[0087] The die bottom edge 122, the die side surface 123, the die shoulder 124, and the die flange surface 125 may be symmetric or asymmetric with respect to the center line C1 in the width direction of the die 12, similar to the punch shoulder 112, the punch side surface 113, the punch base 114, and the punch flange surface 115.

[0088] The holder 13 is positioned outside the punch 11 in the width direction of the first mold 10. The holder 13 is positioned on both the left and right sides of the punch 11. Preferably, the surface 131 of the holder 13 on the die flange surface 125 side is inclined with respect to the horizontal plane in a cross-sectional view of the first mold 10, corresponding to the die flange surface 125. In this embodiment, the surface 131 of the holder 13 slopes downward as it moves outward in the width direction of the first mold 10.

[0089] In this embodiment, the holder 13 includes a bead 131a. The bead 131a is provided on the surface 131 of the holder 13 on the die flange surface 125 side. In this embodiment, the bead 131a has a stepped shape. By providing a stepped bead 131a on the surface 131 of the holder 13, the portion of the surface 131 that is inward in the width direction relative to the bead 131a protrudes toward the die flange surface 125 compared to the portion that is outward in the width direction. The portion of the die flange surface 125 that faces the holder 13 also has a stepped shape corresponding to the bead 131a of the holder 13.

[0090] However, the bead 131a of the holder 13 does not necessarily have to be stepped. The bead 131a may have a convex or concave shape on the die flange surface 125 side. That is, the bead 131a may be a convex or concave portion provided on the surface 131 of the holder 13. In this case, a concave or convex portion is formed on the die flange surface 125 corresponding to the convex or concave bead 131a.

[0091] The bead 131a extends in the longitudinal direction of the first mold 10. Preferably, the bead 131a extends in the longitudinal direction of the first mold 10 across the entire holder 13.

[0092] As shown in Figure 3, the first die 10 has line lengths L11, L12, L13, and L14 in its cross-sectional view. Line length L11 is the length of the surface of the punch 11 from the center line C1 of the punch 11 to the end of the punch base 114 on the punch flange surface 115 side in the cross-sectional view of the first die 10. Line length L12 is the length along the surface of the punch 11 and the surface of the holder 13 from the center line C1 of the punch 11 to the bead 131a of the holder 13 in the cross-sectional view of the first die 10. Line length L12 is the line length from the center line C1 to the bead 131a when the holder 13 is at its bottom dead center, as shown by the dashed line in Figure 3.

[0093] The wire length L13 is the length of the surface of the punch 11 from the center line C1 of the punch 11 to the boundary between the punch 11 and the holder 13 in a cross-sectional view of the first mold 10. The wire length L14 is the length of the surface of the die 12 from the center line C1 of the die 12 to the step 125a of the die flange surface 125 in a cross-sectional view of the first mold 10. The wire length L13 is greater than or equal to the wire length L14. The wire length L13 may be greater than the wire length L14. In this case, the boundary between the punch 11 and the holder 13 is located outside the step 125a of the die flange surface 125 in the width direction of the first mold 10.

[0094] The first die 10 is installed in the press device 100 (Figure 1) such that the punch 11 and holder 13 are located below the die 12. As shown in Figure 2, the first die 10 is attached to the press device 100 (Figure 1) by, for example, a bolster 51, a slide 52, die holders 61, 62, and a cushion 63.

[0095] The mold holder 61 holds the punch 11. The punch 11 is fixed to the upper surface of the mold holder 61. The mold holder 61 is fixed to the upper surface of the bolster 51. A plate-shaped spacer may be inserted between the mold holder 61 and the bolster 51 to adjust the position of the punch 11 in the vertical direction.

[0096] The die holder 62 is positioned above the die holder 61. The die holder 62 holds the die 12. The die holder 62 is fixed to the lower surface of the slide 52. A plate-shaped spacer may be inserted between the die holder 62 and the slide 52 to adjust the vertical position of the die 12. The slide 52 is configured to be able to move up and down by, for example, a mechanical or hydraulic mechanism (not shown). As the slide 52 moves up and down, the die 12 moves up and down relative to the punch 11 and the holder 13. The direction of relative approach and separation of the die 12 with respect to the punch 11 and the holder 13 is the pressing direction of the first die 10.

[0097] The cushion 63 includes left and right cushion pins 631. Each cushion pin 631 supports the holder 13. Each cushion pin 631 is attached to the lower surface of the holder 13. Each cushion pin 631 is configured to be able to move up and down, for example, by a hydraulic mechanism. However, instead of moving the holder 13 up and down by a hydraulic mechanism via the cushion pins 631, the holder 13 may be moved up and down by attaching an elastic mechanism such as a gas spring to the holder 13.

[0098] [Second mold] Figure 4 is a cross-sectional view showing the schematic configuration of the second die 20. As shown in Figure 4, the second die 20 includes a punch 21, a pad 22, a die 23, and a holder 24. The punch 21, pad 22, die 23, and holder 24 extend in a direction intersecting the plane of paper in Figure 4. For the sake of explanation, the direction in which the punch 21, pad 22, die 23, and holder 24 extend will be referred to as the longitudinal direction of the second die 20, and the vertical direction in the plane of paper in Figure 4 will be referred to as the vertical direction or height direction of the second die 20. The direction perpendicular to the plane consisting of the longitudinal direction and the vertical direction will be referred to as the left-right direction or width direction of the second die 20. The cross-section of the second die 20 is the cross-section of the second die 20 when cut by a plane perpendicular to the longitudinal direction. Figure 5 is a partially enlarged view of the second die 20 shown in Figure 4.

[0099] Referring to Figures 4 and 5, the punch 21 includes a punch top surface 211, a punch shoulder 212, a punch side surface 213, a punch base 214, and a punch flange surface 215.

[0100] The punch top surface 211 faces the pad 22. The punch top surface 211 extends in the width direction of the second die 20 in a cross-sectional view of the second die 20. The punch top surface 211 has a length (width) W in the width direction of the second die 20. pt2 It has the width W of the punch top surface 211. pt2 The width W of the punch top surface 111 of the first mold 10 is pt1 It is preferable that it be smaller than (Figure 2).

[0101] In the example shown in Figure 4, a groove 211a is formed on the punch top surface 211. Preferably, the groove 211a has substantially the same shape and dimensions as the groove 111a (Figure 2) on the punch top surface 111 of the first die 10. However, the shapes and dimensions of the grooves 111a and 211a may be different.

[0102] On the left and right sides of the punch top surface 211 are provided a punch shoulder 212, a punch side surface 213, a punch base 214, and a punch flange surface 215, respectively. In a cross-sectional view of the second die 20, the left and right punch shoulders 212, punch side surfaces 213, punch base 214, and punch flange surface 215 may be symmetrical or asymmetrical with respect to the center line C2 in the width direction of the punch 21. The center line C2 is typically an imaginary line that passes through the center of the punch top surface 211 in the width direction of the second die 20 and extends in the height direction of the second die 20.

[0103] The punch shoulder 212 is continuous with the punch top surface 211. More specifically, the punch shoulder 212 is provided continuously on the left and right side edges of the punch top surface 211. The punch shoulder 212 has a substantially arc shape in a cross-sectional view of the second die 20, for example.

[0104] The punch side 213 is continuous with the punch shoulder 212. In a cross-sectional view of the second die 20, the punch side 213 extends downward from the punch shoulder 212. The punch side 213 may include a bulge 213a. The bulge 213a is the portion of the punch side 213 that bulges outward in the width direction of the second die 20. The bulge 213a has, for example, a curved shape that is convex outward in the width direction in a cross-sectional view of the second die 20. Preferably, the bulge 213a is formed on the punch side 213 such that, in a cross-sectional view of the second die 20, the portion from its top to the punch base 314 does not have a downward angle. Preferably, the bulge 213a is smoothly connected to the other portion of the punch side 213 via a curve in a cross-sectional view of the second die 20. The amount of bulging of the bulge portion 213a on the punch side surface 213 of the second die 20 may be smaller than the amount of bulging of the bulge portion 113a (Figure 2) on the punch side surface 113 of the first die 10.

[0105] The punch base 214 is continuous with the punch side 213 on the opposite side of the punch shoulder 212. The punch base 214 is provided continuously with the lower end of the punch side 213. The punch base 214 has a substantially arc shape in a cross-sectional view of the second die 20, for example.

[0106] The punch flange surface 215 is continuous with the punch base 214. In a cross-sectional view of the second die 20, the punch flange surface 215 extends outward from the punch base 214 in the width direction of the second die 20. The punch flange surface 215 has an uneven shape 215a in at least a portion of it.

[0107] The punch flange surface 215 includes a convex surface 215b near the punch base 214. The convex surface 215b is located in the portion of the punch flange surface 215 adjacent to the punch base 214. The convex surface 215b protrudes outward from the punch 21 compared to the rest of the punch flange surface 215. More specifically, the convex surface 215b protrudes upward compared to the rest of the punch flange surface 215.

[0108] In a cross-sectional view of the second mold 20, the width W of the punch flange surface 215 is shown. pf2The height H of the punch side 213 is ps2 That's all. The width W of the punch flange surface 215. pf2 The height H of the punch side 213 is ps2 It may be larger than that. Width W of punch flange surface 215 pf2 This is the length of the punch flange surface 215 in the width direction of the second die 20. In this embodiment, the height H of the punch side surface 213 is also shown. ps2 This height includes the punch top surface 211, the punch shoulder 212, and the punch base 214. That is, in the cross-section of the second die 20, the distance from the end of the punch base 214 on the punch flange surface 215 side to the highest position in the height direction of the punch top surface 211 is the height H of the punch side surface 213. ps2 Let's assume that H ps2 This is the maximum distance in the height direction from the end of the punch base 214 on the punch flange surface 215 side to the punch top surface 211, as viewed in cross-section of the second mold 20. The height H of the punch side surface 213. ps2 The height H of the punch side 113 (Figure 3) of the first die 10 is ps1 It may be larger than that. Height H of punch side 213 ps2 This changes along the longitudinal direction of the second mold 20.

[0109] The pad 22 is positioned above the punch top surface 211. The pad 22 faces the punch top surface 211. The bottom surface 221 of the pad 22 has a shape corresponding to the punch top surface 211. In this embodiment, the bottom surface 221 of the pad 22 has a convex portion 221a corresponding to the concave portion 211a of the punch top surface 211.

[0110] The dies 23 are positioned on the left and right sides of the pad 22. The left and right dies 23 may be symmetrical or asymmetrical with respect to the widthwise center line C2 of the punch 21. Each die 23 includes a die bottom edge 231, a die side 232, a die shoulder 233, and a die flange surface 234.

[0111] The die bottom edge 231 is positioned outside the pad 22 in the width direction of the second mold 20. The die bottom edge 231 has a shape corresponding to the punch shoulder 212. In a cross-sectional view of the second mold 20, the die bottom edge 231 has, for example, a substantially arc shape.

[0112] The die side 232 is continuous with the die bottom edge 231. In a cross-sectional view of the second mold 20, the die side 232 extends downward from the die bottom edge 231. The die side 232 has a shape corresponding to the punch side 213. In this embodiment, the die side 232 includes a recessed portion 232a, corresponding to the bulge 213a of the punch side 213. The recessed portion 232a is the portion of the die side 232 that recesses outward in the width direction of the second mold 20. The recessed portion 232a has, for example, a concave curved shape outward in the width direction in a cross-sectional view of the second mold 20. Preferably, the recessed portion 232a is smoothly connected to the other portion of the die side 232 via a curve in a cross-sectional view of the second mold 20.

[0113] The die shoulder 233 is continuous with the die side 232 on the opposite side of the die bottom edge 231. The die shoulder 233 is provided continuously with the lower end of the die side 232. The die shoulder 233 has a shape corresponding to the punch base 214. The die shoulder 233 may have a substantially arc shape in a cross-sectional view of the second die 20, for example.

[0114] The die flange surface 234 is continuous with the die shoulder 233. In a cross-sectional view of the second mold 20, the die flange surface 234 extends outward from the die shoulder 233 in the width direction of the second mold 20. The die flange surface 234 has an uneven shape 234a in at least a portion thereof, corresponding to the uneven shape 215a of the punch flange surface 215.

[0115] The die flange surface 234 includes a concave surface 234b in the vicinity of the die shoulder 233. The concave surface 234b is located in the portion of the die flange surface 234 adjacent to the die shoulder 233. The concave surface 234b is recessed inward from the die 23 compared to the rest of the die flange surface 234. More specifically, the concave surface 234b is recessed upward compared to the rest of the die flange surface 234.

[0116] The die flange surface 234 further includes a step 234c. The step 234c is provided on the portion of the die flange surface 234 that faces the die shoulder 233. The step 234c is located, for example, outside the concave surface 234b in the width direction of the second mold 20. The step 234c may also be located near the concave surface 234b. The step 234c causes the clearance between the punch 21 and the die 23 to be greater on the inside than on the outside in the width direction of the second mold 20 when the second mold 20 is closed.

[0117] In a cross-sectional view of the second mold 20, the width W of the die flange surface 234 is shown. df2 The height H of the die side 232 is ds2 That concludes the explanation. In the cross-sectional view of the second mold 20, the width W of the die flange surface 234 is shown. df2 The height H of the die side 232 is ds2 It may be larger than that. Width W of die flange surface 234 df2 This is the length of the die flange surface 234 in the width direction of the second mold 20. The height H of the die side surface 232. ds2 This height includes the die bottom edge 231 and the die shoulder 233. That is, in a cross-sectional view of the second mold 20, the distance from the end of the die shoulder 233 on the die flange surface 234 side to the highest position in the height direction of the die bottom edge 231 is the height H of the die side 232. ds2 Let's assume the height is H. ds2 This is the maximum distance in the height direction from the end of the die shoulder 233 on the die flange surface 234 side to the die bottom edge 231, as viewed in cross-section of the second mold 20. The height H of the die side surface 232. ds2 This changes along the longitudinal direction of the second mold 20.

[0118] The die flange surface 234 extends beyond the punch flange surface 215 in the width direction of the second mold 20. That is, the width W of the die flange surface 234 df2 The width W of the punch flange surface 215 is pf2 It is larger than that. Therefore, the die flange surface 234 faces the punch flange surface 215 and the holder 24.

[0119] The holder 24 is positioned outside the punch 21 in the width direction of the second mold 20. The holder 24 is positioned on both the left and right sides of the punch 21.

[0120] The holder 24 includes a bead 241a on its surface 241 facing the die flange surface 234. The bead 241a is provided on the surface 241 of the holder 24 facing the die flange surface 234. In this embodiment, the bead 241a has a stepped shape. By providing a stepped bead 241a on the surface 241 of the holder 24, the portion of the surface 241 that is inward in the width direction relative to the bead 241a protrudes toward the die flange surface 234 compared to the portion that is outward in the width direction. The portion of the die flange surface 234 facing the holder 24 also has a stepped shape corresponding to the bead 241a of the holder 24.

[0121] However, the bead 241a of the holder 24 does not necessarily have to be stepped. The bead 241a may have a convex or concave shape on the die flange surface 234 side. That is, the bead 241a may be a convex or concave portion provided on the surface 241 of the holder 24. In this case, a concave or convex portion is formed on the die flange surface 234 corresponding to the convex or concave bead 241a.

[0122] The bead 241a extends in the longitudinal direction of the second mold 20. Preferably, the bead 241a extends in the longitudinal direction of the second mold 20 across the entire holder 24.

[0123] As shown in Figure 5, the second die 20 has line lengths L21 and L22 in its cross-sectional view. Line length L21 is the length of the surface of the punch 21 from the center line C2 of the punch 21 to the end of the punch base 214 on the punch flange surface 215 side in the cross-sectional view of the second die 20. This line length L21 is substantially equal to the line length L11 of the first die 10 (Figure 3). The difference between the line length L11 of the first die 10 and the line length L21 of the second die 20 is, for example, 5.0 mm or less.

[0124] The wire length L22 is the length along the surface of the punch 21 and the surface of the holder 24, from the center line C2 of the punch 21 to the bead 241a of the holder 24, in a cross-sectional view of the second die 20. The wire length L22 is the length from the center line C2 to the bead 241a when the holder 24 is at its bottom dead center, as shown by the dashed line in Figure 5. The wire length L22 is substantially equal to the wire length L12 of the first die 10 (Figure 3). The difference between the wire length L12 of the first die 10 and the wire length L22 of the second die 20 is, for example, 5.0 mm or less.

[0125] The second die 20 is installed in the press device 100 (Figure 1) such that the punch 21 and holder 24 are located below the pad 22 and die 23. As shown in Figure 4, the second die 20 is attached to the press device 100 (Figure 1) by, for example, a bolster 51, a slide 52, die holders 71, 72, a cushion 73, and an elastic member 74.

[0126] The die holder 71 holds the punch 21. The punch 21 is fixed to the upper surface of the die holder 71. If the press device 100 (Figure 1) is a transfer press device, the die holder 71 is fixed to a bolster 51 common to the die holder 61 (Figure 2) for the punch 11 of the first die 10. A plate-shaped spacer may be inserted between the die holder 71 and the bolster 51 to adjust the position of the punch 21 in the vertical direction.

[0127] The die holder 72 is located below the die holder 71. The die holder 72 holds the die 23. If the press device 100 (Figure 1) is a transfer press device, the die holder 72 is fixed to a slide 52 common to the die holder 62 (Figure 2) for the die 12 of the first die 10. A plate-shaped spacer may be inserted between the die holder 72 and the slide 52 to adjust the position of the die 23 in the vertical direction. As the slide 52 moves up and down, the die 23 moves up and down relative to the punch 21 and the holder 24. The relative approach and separation direction of the die 23 relative to the punch 21 and the holder 24 is the pressing direction of the second die 20.

[0128] The cushion 73 includes left and right cushion pins 731. Each cushion pin 731 supports the holder 24. Each cushion pin 731 is attached to the lower surface of the holder 24. Each cushion pin 731 is configured to be able to move up and down, for example, by a hydraulic mechanism. However, instead of moving the holder 24 up and down by a hydraulic mechanism via the cushion pins 431, the holder 24 may be moved up and down by attaching an elastic mechanism such as a gas spring to the holder 24.

[0129] The elastic member 74 supports the pad 22. The pad 22 is attached to the mold holder 72 via the elastic member 74. The elastic member 74 is a member that can expand and contract in the pressing direction. The elastic member 74 is composed of, for example, a spring or a fluid pressure cylinder. The pad 22 may also be attached to an actuator (not shown). However, the method using the elastic member 74 allows for a simpler structure of the press device 100 (Figure 1) than the actuator type.

[0130] [Third mold] Figure 6 is a cross-sectional view showing the schematic configuration of the third die 30. As shown in Figure 6, the third die 30 includes a punch 31, a pad 32, and a die 33. The punch 31, pad 32, and die 33 extend in a direction intersecting the plane of the paper in Figure 6. For the sake of explanation, the direction in which the punch 31, pad 32, and die 33 extend will be referred to as the longitudinal direction of the third die 30, and the vertical direction in the plane of the paper in Figure 6 will be referred to as the vertical direction or height direction of the third die 30. In addition, the direction perpendicular to the plane consisting of the longitudinal direction and the vertical direction will be referred to as the left-right direction or width direction of the third die 30. The cross-section of the third die 30 is the cross-section of the third die 30 when cut by a plane perpendicular to the longitudinal direction.

[0131] The punch 31 includes a punch top surface 311, a punch shoulder 312, a punch side surface 313, a punch base 314, and a punch flange surface 315.

[0132] The punch top surface 311 extends in the width direction of the third die 30 in a cross-sectional view of the third die 30. The length (width) of the punch top surface 311 in the width direction of the third die 30 is, for example, the width W of the punch top surface 211 of the second die 20. pt2 This is essentially equivalent to (Figure 4).

[0133] The punch top surface 311 can have a shape corresponding to the punch top surface 211 of the second die 20 (Figure 4). In the example shown in Figure 6, the punch top surface 311 has a groove portion 311a, similar to the punch top surface 211 of the second die 20.

[0134] On the left and right sides of the punch top surface 311 are provided a punch shoulder 312, a punch side surface 313, a punch base 314, and a punch flange surface 315, respectively. In a cross-sectional view of the third die 30, the left and right punch shoulders 312, punch side surfaces 313, punch base 314, and punch flange surface 315 may be symmetrical or asymmetrical with respect to the center line C3 in the width direction of the punch 31 and pad 32. The center line C3 is typically an imaginary line that passes through the center of the punch top surface 311 in the width direction of the third die 30 and extends in the height direction of the third die 30.

[0135] The punch shoulder 312 is continuous with the punch top surface 311. More specifically, the punch shoulder 312 is provided continuously on the left and right side edges of the punch top surface 311. The punch shoulder 312 has a substantially arc shape in a cross-sectional view of the third die 30, for example.

[0136] The punch side 313 is continuous with the punch shoulder 312. In a cross-sectional view of the third die 30, the punch side 313 extends downward from the punch shoulder 312. Unlike the punch sides 113 and 213 of dies 10 and 20 (Figures 2 and 4), the punch side 313 does not have a bulge that protrudes outward in the width direction of the third die 30. In a cross-sectional view of the third die 30, the punch side 313 may be, for example, substantially straight.

[0137] The punch base 314 is continuous with the punch side 313 on the opposite side of the punch shoulder 312. The punch base 314 is provided continuously with the lower end of the punch side 313. The punch base 314 has a substantially arc shape in a cross-sectional view of the third die 30, for example.

[0138] The punch flange surface 315 is continuous with the punch base 314. In a cross-sectional view of the third die 30, the punch flange surface 315 extends outward from the punch base 314 in the width direction of the third die 30. The punch flange surface 315 has a shape that substantially corresponds to, for example, the punch flange surface 215 of the second die 20 (Figure 4). In the example shown in Figure 6, the punch flange surface 315 has an uneven shape 315a in at least a portion of it, corresponding to the punch flange surface 215 of the second die 20.

[0139] In a cross-sectional view of the third die 30, the width of the punch flange surface 315 is greater than or equal to the height of the punch side surface 313. In a cross-sectional view of the third die 30, the width of the punch flange surface 315 may be greater than the height of the punch side surface 313. The width of the punch flange surface 315 is the length of the punch flange surface 315 in the width direction of the third die 30. The height of the punch side surface 313 is the distance from the end of the punch flange surface 315 on the punch base 314 side to the highest position in the height direction of the punch top surface 311, as with the first die 10 (Figure 3) and the second die 20 (Figure 5), when viewing the third die 30 in cross-section. The height of the punch side surface 313 is the maximum distance in the height direction from the end of the punch flange surface 315 on the punch base 314 side to the punch top surface 311, when viewing the third die 30 in cross-section. The height of the punch side surface 313 is the height H of the punch side surface 213 of the second die 20. ps2 It is preferable that it is substantially equal to (Figure 5). The height of the punch side surface 313 varies along the longitudinal direction of the third die 30, similar to the punch side surface 213 of the second die 20.

[0140] The pad 32 includes a pad bottom surface 321, a pad bottom edge 322, a pad side surface 323, a pad shoulder 324, and a pad flange surface 325.

[0141] The pad bottom surface 321 faces the punch top surface 311. The pad bottom surface 321 has a shape corresponding to the punch top surface 311. In this embodiment, the pad bottom surface 321 has a convex portion 321a corresponding to the concave portion 311a of the punch top surface 311.

[0142] The pad bottom edge 322, pad side 323, pad shoulder 324, and pad flange surface 325 are provided on the left and right sides of the pad bottom surface 321, respectively. The pad bottom edge 322, pad side 323, pad shoulder 324, and pad flange surface 325 may be symmetrical or asymmetrical with respect to the center line C3 in the width direction of the pad 32, similar to the punch shoulder 312, punch side 313, punch base 314, and punch flange surface 315.

[0143] The pad bottom edge 322 is continuous with the pad bottom surface 321. More specifically, the pad bottom edge 322 is provided continuously with the left and right side edges of the pad bottom surface 321. The pad bottom edge 322 has a shape corresponding to the punch shoulder 312. Like the punch shoulder 312, the pad bottom edge 322 has a substantially arc shape in a cross-sectional view of the third die 30, for example.

[0144] The pad side 323 is continuous with the pad bottom edge 322. In a cross-sectional view of the third die 30, the pad side 323 extends downward from the pad bottom edge 322. The pad side 323 has a shape corresponding to the punch side 313.

[0145] The pad shoulder 324 is continuous with the pad side surface 323 on the opposite side of the pad bottom edge 322. The pad shoulder 324 is provided continuously with the lower end of the pad side surface 323. The pad shoulder 324 has a shape corresponding to the punch base 314. Like the punch base 314, the pad shoulder 324 has a substantially arc shape in a cross-sectional view of the third die 30, for example.

[0146] The pad flange surface 325 is continuous with the pad shoulder 324. In a cross-sectional view of the third die 30, the pad flange surface 325 extends outward from the pad shoulder 324 in the width direction of the third die 30. The pad flange surface 325 faces the punch flange surface 315. The pad flange surface 325 has a shape corresponding to the punch flange surface 315. In the example shown in Figure 6, the pad flange surface 325 has an uneven shape 325a in at least a portion of it, corresponding to the punch flange surface 315.

[0147] The die 33 is positioned outside the punch 31 and pad 32 in the width direction of the third mold 30. The die 33 is positioned adjacent to the left and right sides of the pad 32, for example. In the third mold 30, the die 33 and punch 31 may function as trim blades for cutting the edges of the material. For example, the die 33 may have a trim blade 331 as an upper blade, and the punch 31 may have a trim blade 316 as a lower blade. Alternatively, the mold structure of the punch 31 and / or die 33 may be an insert mold, where only the area around the trim blades 316 and 331 is made of a different steel material. The trim blades 316 and 331 may be made of a hard mold material to ensure stable cutting, but hard mold materials are generally expensive, so an insert structure is more economical.

[0148] The third die 30 has a line length L31 in its cross-sectional view. The line length L31 is the length of the surface of the punch 31 from the center line C3 of the punch 31 to the end of the punch base 314 on the punch flange surface 315 side, in the cross-sectional view of the third die 30. This line length L31 is substantially equal to the line length L21 of the second die 20 (Figure 5). The difference between the line length L21 of the second die 20 and the line length L31 of the third die 30 is, for example, 5.0 mm or less.

[0149] Although not shown in the figures, if the press device 100 (Figure 1) is a transfer press device, the pad 32 and die 33 of the third die 30 may be mounted on a slide 52 (Figures 2 and 4) that is common to the first die 10 and the second die 20. The pad 32 and die 33 can move closer to and further away from the punch 31 by raising and lowering the slide 52. The pad 32 may be mounted on the slide 52 via an elastic member, similar to the pad 22 (Figure 4) of the second die 20.

[0150] [Fourth mold] Figure 7 is a cross-sectional view showing the schematic configuration of the fourth die 40. As shown in Figure 7, the fourth die 40 includes a holder 41, a die 42, and a punch 43. The holder 41, die 42, and punch 43 extend in a direction intersecting the plane of paper in Figure 7. For the sake of explanation, the direction in which the holder 41, die 42, and punch 43 extend will be referred to as the longitudinal direction of the fourth die 40, and the vertical direction in the plane of paper in Figure 7 will be referred to as the vertical direction (or height direction) of the fourth die 40. Furthermore, the direction perpendicular to the plane consisting of the longitudinal direction and the vertical direction will be referred to as the left-right direction or width direction of the fourth die 40. The cross-section of the fourth die 40 is the cross-section of the fourth die 40 when cut by a plane perpendicular to the longitudinal direction.

[0151] The holder 41 includes a holder top surface 411, a holder shoulder 412, a holder side surface 413, a holder base 414, and a holder flange surface 415.

[0152] The holder top surface 411 extends in the width direction of the fourth die 40 in a cross-sectional view of the fourth die 40. The length (width) of the holder top surface 411 in the width direction of the fourth die 40 is, for example, the width W of the punch top surface 211 of the second die 20. pt2 (Figure 4), and substantially equal to the width of the punch top surface 311 of the third die 30 (Figure 6).

[0153] The holder top surface 411 can have a shape corresponding to the punch top surface 311 of the third die 30 (Figure 6). In the example shown in Figure 7, the holder top surface 411 has a groove portion 411a, similar to the punch top surface 311 of the third die 30.

[0154] On either side of the holder top surface 411 are holder shoulders 412, holder sides 413, holder bases 414, and holder flange surfaces 415. In a cross-sectional view of the fourth mold 40, the left and right holder shoulders 412, holder sides 413, holder bases 414, and holder flange surfaces 415 may be symmetrical or asymmetrical with respect to the center line C4 in the width direction of the holder 41 and die 42. The center line C4 is typically an imaginary line that passes through the center of the holder top surface 411 in the width direction of the fourth mold 40 and extends in the height direction of the fourth mold 40.

[0155] The holder shoulders 412 are continuous with the holder top surface 411. More specifically, the holder shoulders 412 are provided continuously with the left and right side edges of the holder top surface 411. The holder shoulders 412 have a substantially arc shape in a cross-sectional view of the fourth mold 40, for example.

[0156] The holder side 413 is continuous with the holder shoulder 412. In a cross-sectional view of the fourth die 40, the holder side 413 extends downward from the holder shoulder 412. The holder side 413 has substantially the same shape as, for example, the punch side 313 of the third die 30 (Figure 6).

[0157] The holder base 414 is continuous with the holder side 413 on the opposite side of the holder shoulder 412. The holder base 414 is provided continuously with the lower end of the holder side 413. The holder base 414 has a substantially arc shape in a cross-sectional view of the fourth mold 40, for example.

[0158] The holder flange surface 415 is continuous with the holder base 414. In a cross-sectional view of the fourth die 40, the holder flange surface 415 extends outward from the holder base 414 in the width direction of the fourth die 40. The holder flange surface 415 has a shape corresponding to the punch flange surface 315 of the third die 30 (Figure 6). In the example shown in Figure 7, the holder flange surface 415 has an uneven shape 415a in at least a part of it, corresponding to the punch flange surface 315.

[0159] In a cross-sectional view of the fourth die 40, the width of the holder flange surface 415 is greater than or equal to the height of the holder side surface 413. In a cross-sectional view of the fourth die 40, the width of the holder flange surface 415 may be greater than the height of the holder side surface 413. The width of the holder flange surface 415 is the length of the holder flange surface 415 in the width direction of the fourth die 40. The height of the holder side surface 413 is the distance from the end of the holder flange surface 415 on the holder base 414 side to the highest position in the height direction of the holder top surface 411, as with the first die 10 (Figure 3) and the second die 20 (Figure 5), when viewing the fourth die 40 in cross-section. The height of the holder side surface 413 is the maximum distance in the height direction from the end of the holder flange surface 415 on the holder base 414 side to the holder top surface 411, when viewing the fourth die 40 in cross-section. The height of the holder side surface 413 is the height H of the punch side surface 213 of the second die 20. ps2 Preferably, the height of the holder side 413 is substantially equal to the height of the punch side 313 of the third die 30 (Figure 5) and (Figure 6). The height of the holder side 413 varies along the longitudinal direction of the fourth die 40, similar to the punch side 213 of the second die 20 and the punch side 313 of the third die 30.

[0160] The die 42 includes a die bottom surface 421, a die bottom edge 422, a die side surface 423, a die shoulder 424, and a die flange surface 425.

[0161] The die bottom surface 421 faces the holder top surface 411. The die bottom surface 421 has a shape corresponding to the holder top surface 411. In this embodiment, the die bottom surface 421 has a convex portion 421a corresponding to the concave portion 411a of the holder top surface 411.

[0162] The die bottom edge 422, die side 423, die shoulder 424, and die flange surface 425 are provided on the left and right sides of the die bottom surface 421, respectively. The die bottom edge 422, die side 423, die shoulder 424, and die flange surface 425 may be symmetrical or asymmetrical with respect to the center line C4 in the width direction of the die 42, similar to the holder shoulder 412, holder side 413, holder base 414, and holder flange surface 415.

[0163] The die bottom edge 422 is continuous with the die bottom surface 421. More specifically, the die bottom edge 422 is provided continuously with the left and right side edges of the die bottom surface 421. The die bottom edge 422 has a shape corresponding to the holder shoulder 412. Like the holder shoulder 412, the die bottom edge 422 has a substantially arc shape in a cross-sectional view of the fourth die 40, for example.

[0164] The die side 423 is continuous with the die bottom edge 422. In a cross-sectional view of the fourth mold 40, the die side 423 extends downward from the die bottom edge 422. The die side 423 has a shape corresponding to the holder side 413.

[0165] The die shoulder 424 is continuous with the die side 423 on the opposite side of the die bottom edge 422. The die shoulder 424 is provided continuously with the lower end of the die side 423. The die shoulder 424 has a shape corresponding to the holder base 414. Like the holder base 414, the die shoulder 424 has a substantially arc shape in a cross-sectional view of the fourth die 40, for example.

[0166] The die flange surface 425 is continuous with the die shoulder 424. In a cross-sectional view of the fourth mold 40, the die flange surface 425 extends outward from the die shoulder 424 in the width direction of the fourth mold 40. The die flange surface 425 faces the holder flange surface 415. The die flange surface 425 has a shape corresponding to the holder flange surface 415. In the example shown in Figure 7, the die flange surface 425 has an uneven shape 425a in at least a portion of it, corresponding to the holder flange surface 415.

[0167] The fourth mold 40 has a line length L41 in its cross-sectional view. The line length L41 is the length of the surface of the holder 41 from the center line C4 of the holder 41 to the end of the holder base 414 on the holder flange surface 415 side, in the cross-sectional view of the fourth mold 40. This line length L41 is substantially equal to the line length L21 of the second mold 20 (Figure 5). Also, the line length L41 is substantially equal to the line length L31 of the third mold 30 (Figure 6). The difference between the line length L21 of the second mold 20 and the line length L41 of the fourth mold 40 is, for example, 5.0 mm or less. The difference between the line length L31 of the third mold 30 and the line length L41 of the fourth mold 40 is also, for example, 5.0 mm or less.

[0168] The punch 43 is positioned outside the holder 41 and die 42 in the width direction of the fourth mold 40. The punch 43 is positioned adjacent to both the left and right sides of the holder 41.

[0169] Although not shown in the illustration, if the press device 100 (Figure 1) is a transfer press device, the die 42 of the fourth die 40 may be mounted on a slide 52 (Figures 2 and 4) that is common to the first die 10 and the second die 20. Alternatively, the die 12 of the first die 10, the die 23 of the second die 20, the pad 32 and die 33 of the third die 30, and the die 42 of the fourth die 40 may all be mounted on a common slide 52. The die 42 can move closer to and further away from the holder 41 by raising and lowering the slide 52. The holder 41 is configured to move up and down independently of the punch 43, for example, by a cushioning mechanism.

[0170] [Method for manufacturing press-formed products] Next, a method for manufacturing press-formed products using the press device 100 will be described with reference to the figures. The manufacturing method according to this embodiment comprises a preparation step, a first step (deep drawing step), a second step (gripping and bending step), a third step (punching step), and a fourth step (thrust bending step).

[0171] (preparation process) Referring to Figure 8, the preparation step is the step of preparing the material 200. The material 200 is typically a tailored blank. The material 200 includes a plurality of metal sheets 201, 202 that are butt-joined. Metal sheet 201 is positioned between two metal sheets 202. Each metal sheet 202 is joined to metal sheet 201 by, for example, laser welding, plasma welding, or mash seam welding. In the example shown in Figure 8, the thickness of metal sheet 201 is greater than the thickness of each metal sheet 202. In this case, the tensile strength of metal sheet 201 is the same as or greater than the tensile strength of each metal sheet 202. However, the thickness of metal sheet 201 may be the same as the thickness of each metal sheet 202. In this case, the tensile strength of metal sheet 201 is greater than the tensile strength of each metal sheet 202.

[0172] (Deep drawing process) As shown in Figures 9A to 9D, in the deep drawing process, which is the first molding step, the first mold 10 is used to press-form the material 200 into an intermediate molded product 300. The deep drawing process includes the steps of clamping the material 200 between the die 12 and holder 13 of the first mold 10, and while the material 200 is clamped between the die 12 and holder 13, bringing the punch 11 and die 12 relatively close together to form the top plate 301 and vertical walls 303 of the intermediate molded product 300 using the punch 11 and die 12. The deep drawing process will be described in detail below.

[0173] First, referring to Figure 9A, when the deep drawing process is started, the first die 10 is at top dead center. In this state, the material 200 is placed on the punch 11 and holder 13.

[0174] Next, the die 12 is brought relatively closer to the punch 11 and holder 13 in the pressing direction. Specifically, as shown in Figure 9B, after the material 200 is placed on the punch 11 and holder 13, the die 12 is lowered toward the punch 11 and holder 13 by lowering the slide 52. As a result, the material 200 is first clamped between the die flange surface 125 and the holder 13. The die flange surface 125 and the holder 13 clamp the metal plate 202 of the material 200 which has a smaller plate thickness.

[0175] With the material 200 held between the die flange surface 125 and the holder 13, the die 12 descends further. The holder 13, along with the die flange surface 125, continues to hold the material 200 in place and descends together with the cushion pin 631, applying tension to the material 200. Referring to Figure 9C, when the die 12 reaches its bottom dead center with the material 200 held between the die flange surface 125 and the holder 13, the material 200 is held between the punch 11 and the die 12 and formed into an intermediate molded product 300. After raising the slide 52 and the die 12 to their top dead centers, the intermediate molded product 300 is removed from the first mold 10.

[0176] As shown in Figure 9D, the intermediate molded product 300 includes a top plate 301, left and right ridge portions 302, left and right vertical walls 303, and left and right flanges 304. The top plate 301 has a recessed portion 301a formed by the recessed portion 111a of the punch top surface 111 and the convex portion 121a (Figure 2) of the die bottom surface 121. The left and right vertical walls 303 are each connected to the top plate 301 via the ridge portions 302. In the portions of the top plate 301 adjacent to each ridge portion 302, a convex portion 301b is formed by being sandwiched between the convex surface 111b of the punch top surface 111 and the concave surface 121b (Figure 2) of the die bottom surface 121. The left and right flanges 304 each extend outward in the width direction from the vertical walls 303 of the intermediate molded product 300. Each flange 304 has a shape that corresponds to the bead 131a of the holder 13 (Figure 2). In the example shown in Figure 9D, a stepped bead portion 304a is formed at the widthwise end of each flange 304.

[0177] (Gripping and bending process) After the deep drawing process, the intermediate molded product 300 is transported from the first mold 10 to the second mold 20 by a transport mechanism (not shown) provided in the press device 100 (Figure 1). As shown in Figures 10A to 10F, in the gripping and bending process, which is the second molding process, the second mold 20 is used to press-work the intermediate molded product 300 obtained in the deep drawing process. The gripping and bending process includes the steps of: gripping the top plate 301 of the intermediate molded product 300 between the punch 21 and the pad 22; bringing the punch 21 and the die 23 relatively close together while the top plate 301 is gripped between the punch 21 and the pad 22, but the widthwise end of the intermediate molded product 300 is not gripped between the die 23 and the holder 24, and starting molding by the punch 21 and the die 23; gripping the end of the intermediate molded product 300 between the die 23 and the holder 24 before the flange 304 of the intermediate molded product 300 is formed by the relatively close punch 21 and the die 23; and forming the flange 304 with the punch 21 and the die 23 while tension is applied to the flange 304 by the end of the intermediate molded product 300 being gripped between the die 23 and the holder 24, thereby forming an uneven shape on the flange 304. The gripping and bending process will be described in detail below.

[0178] Referring to Figure 10A, when the intermediate molded product 300 is transported to the second mold 20, the pad 22 and die 23 are at top dead center together with the slide 52. The intermediate molded product 300 is placed on the punch top surface 211. The width W of the punch top surface 211. pt2 (Figure 4) shows the width W of the punch top surface 111 of the first mold 10 used in the previous process. pt1 It is smaller than (Figure 2). Therefore, when the intermediate molded product 300 is placed on the punch top surface 211, the ridge portion 302 is positioned outside the punch shoulder 212 in the width direction of the second mold 20. The protrusion 301b of the top plate 301 is positioned in the vicinity of the punch shoulder 212.

[0179] As shown by the dashed line in Figure 10A, in the initial state, the end (upper end) of the holder 24 on the die flange surface 234 side is located between the punch shoulder 212 and the punch flange surface 215 in the pressing direction of the second die 20. More preferably, in the initial state, the upper end of the holder 24 is located in the range where the punch base 214 exists in the pressing direction of the second die 20. The upper end of the holder 24 is located, for example, slightly above the uppermost edge of the uneven shape 215a of the punch flange surface 215. The initial state is the state at the start of press working by the second die 20, and the second die 20 is at top dead center.

[0180] With the intermediate molded product 300 placed on the top surface 211 of the punch, the pad 22 and die 23 are brought relatively closer to the punch 21 and holder 24. More specifically, after the intermediate molded product 300 as raw material is placed on the top surface 211 of the punch, the slide 52 is lowered, causing the pad 22 and die 23 to be lowered together with the slide 52 towards the punch 21 and holder 24.

[0181] Referring to Figure 10B, as the pad 22 and die 23 descend, the pad 22 first contacts the top plate 301 of the intermediate molded product 300 on the punch top surface 211, and the top plate 301 is pressed down by the pad 22. As the slide 52 is further lowered while the top plate 301 is held between the punch top surface 211 and the pad 22, the elastic member 74 connecting the pad 22 to the slide 52 contracts, and the die 23 descends relative to the pad 22.

[0182] As shown in Figure 10C, as the top plate 301 of the intermediate molded product 300 is held down by the punch top surface 211 and the pad 22, the die 23 is lowered further, causing the die 23 to gradually approach the punch 21, and molding by the punch 21 and die 23 proceeds. In the initial stages of molding, the die 23 and holder 24 do not grip the flange 304 of the intermediate molded product 300.

[0183] Referring to Figure 10D, the upper end of the holder 24 contacts the flange 304 of the intermediate molded product 300 before the flange 304 of the intermediate molded product 300 is completely clamped by the punch 21 and die 23. The holder 24 contacts the flange 304 of the intermediate molded product 300 prior to the punch flange surface 215, and together with the die flange surface 234, clamps the widthwise end of the flange 304. That is, the end of the flange 304 of the intermediate molded product 300 is clamped by the die 23 and the holder 24 just before the imparting of the uneven shape to the flange 304 by the punch 21 and die 23 begins. At this time, the bead portion 304a of the flange 304 is positioned in approximately the same location as the bead 241a of the holder 24 in the widthwise direction of the second mold 20.

[0184] Subsequently, as the die 23 is lowered further, the holder 24, along with the cushion pin 731, descends while gripping the flange 304 of the intermediate molded product 300 together with the die flange surface 234. As a result, the end of the flange 304 remains gripped by the die flange surface 234 and the holder 24, while the rest of the intermediate molded product 300 is formed by the punch 21 and the die 23. Referring to Figure 10E, when the die 23 reaches its bottom dead center, the intermediate molded product 300 is completely clamped by the punch 21 and the die 23 to become the press-formed product 400. At this time, the ridge portion 302 (Figure 10A) of the intermediate molded product 300 is bent back by being squeezed between the punch 21 and the die 23. Also, the convex portion 301b (Figure 10A) of the ridge portion 302 is crushed by the die 23, causing deformation of the convex portion 301b.

[0185] At the bottom dead center of the second die 20, the end (upper end) of the holder 24 on the die flange surface 234 side is positioned in the same location as the punch flange surface 215 in the pressing direction. That is, when the holder 24 is at the bottom dead center, in a cross-sectional view of the second die 20, the position of the end of the punch flange surface 215 on the holder 24 side substantially coincides with the position of the end of the holder 24 on the punch flange surface 215 side in the pressing direction.

[0186] The press-formed product 400 is removed from the second mold 20 after the slide 52 and die 23 have been raised to top dead center. As shown in Figure 10F, the press-formed product 400 includes a top plate 401, left and right ridges 402, left and right vertical walls 403, and left and right flanges 404. The left and right vertical walls 403 are each connected to the top plate 401 via the ridges 402. The left and right flanges 404 each extend outward from the vertical walls 403. Each flange 404 has a recessed portion 404a formed by the punch flange surface 215 and the die flange surface 234 (Figure 4). In addition, the flange 404 has a convex portion 404b formed by being sandwiched between a concave surface 234b provided on the die flange surface 234 and a convex surface 215b provided on the punch 21 (Figure 4). The protrusion 404b is located near the vertical wall 403 and protrudes outward from the press-formed product 400. In the flange 404, the bead portion 304a of the flange 304 (Figure 9D) of the intermediate molded product 300 is maintained.

[0187] (Pulling process) After the gripping and bending process, the press-formed product 400 is transported from the second die 20 to the third die 30 by a transport mechanism (not shown) provided in the press device 100 (Figure 1). As shown in Figures 11A and 11B, in the third molding process, the punching process, the third die 30 is used to trim the press-formed product 400 obtained in the gripping and bending process. More specifically, the portion of each flange 304 of the press-formed product 400 that was gripped by the die 23 and holder 24 in the preceding gripping and bending process is cut off to trim the outer edge of the press-formed product 400.

[0188] As shown by the dashed line in Figure 11A, when the press-formed product 400 is transported to the third die 30, the pad 32 and die 33 are at top dead center. The press-formed product 400 is placed on the punch 31. At this time, the end of the flange 404 of the press-formed product 400 protrudes outward from the punch 31 in the width direction of the third die 30. In this state, the pad 32 and die 33 are brought relatively closer to the punch 31. For example, after the press-formed product 400 is placed on the punch 31, the pad 32 and die 33 are lowered toward the punch 31.

[0189] As shown in Figure 11A, first, the pad 32 contacts the press-formed product 400 on the punch 31, and the press-formed product 400 is pressed down by the pad 32. Referring to Figure 11B, with the press-formed product 400 held between the punch 31 and the pad 32, the die 33 is lowered relative to the pad 32, and the end of the flange 404 is cut by the trim blade 331 of the die 33 and the trim blade 316 of the punch 31. The punch 31 and die 33 cut, for example, the portion of the flange 404 that includes the bead portion 304a. After that, the pad 32 and die 33 rise to the top dead center, and the press-formed product 400 is removed from the third mold 30.

[0190] In the punching process, if necessary, holes can be formed in at least one location on the top plate 401, vertical wall 403, and flange 404 (Figure 10F) of the press-formed product 400. The holes formed in the press-formed product 400 can be used, for example, as reference holes during welding or assembly, or as discharge holes for draining paint liquid during painting.

[0191] (Bending process) After the punching process, the press-formed product 400 is transported from the third die 30 to the fourth die 40 by a transport mechanism (not shown) provided in the press device 100 (Figure 1). In the third molding process, the burr-bending process, the outer edge of the flange 404 of the press-formed product 400 is bent, as shown in Figures 12A and 12B.

[0192] As shown by the dashed line in Figure 12A, when the press-formed product 400 is transported to the fourth mold 40, the die 42 is at its top dead center. The press-formed product 400 is placed on the holder 41. At this time, the end of the flange 404 of the press-formed product 400 protrudes outward from the holder 41 in the width direction of the fourth mold 40. In this state, the die 42 is brought relatively closer to the holder 41. For example, after the press-formed product 400 is placed on the holder 41, the die 42 is lowered toward the holder 41.

[0193] As shown in Figure 12A, first the die 42 contacts the press-formed product 400 on the holder 41, and the press-formed product 400 is pressed down by the die 42. Referring to Figure 12B, the die 42 descends further while holding the press-formed product 400 together with the holder 41. As a result, the die 42 and holder 41 descend relative to the punch 43. Therefore, the punch 43 is pressed from below against the end of the flange 404 of the press-formed product 400, and the end of the flange 404 is bent upward. After that, the fourth die 40 returns to its top dead center, and the press-formed product 400 is removed from the fourth die 40.

[0194] [Press-formed product] Figure 13 is a perspective view showing an example of a manufactured press-formed product 400. In Figure 13, the uneven portions 404a (Figure 12B) formed on each flange 404 are omitted. The length (width) of each flange 404 in the width direction of the press-formed product 400 is greater than or equal to the length (height) of each vertical wall 403 in the height direction of the press-formed product 400. The width of each flange 404 may be greater than the height of both vertical walls 403. In the example shown in Figure 13, the two vertical walls 403 have a height difference in the longitudinal direction of the press-formed product 400. That is, in the longitudinal direction of the press-formed product 400, the vertical wall 403 is higher on one side and lower on the other side.

[0195] The press-formed part 400 can be used as an automobile part. The press-formed part 400 is typically used as a front floor. When the press-formed part 400 is a front floor, most of the flange 404 constitutes the floor side portion, and the top plate 401, ridge portion 402, and vertical wall 403 are included in the floor tunnel portion.

[0196] The thickness of the floor side portion is, for example, smaller than the thickness of the floor tunnel portion. The thickness of the portion of the flange 404 that is the floor side portion is, for example, 0.5 mm or more and 1.0 mm or less. The thickness of the top plate 401, edge portion 402, and vertical wall 403 included in the floor tunnel portion is, for example, 0.8 mm or more and 2.0 mm or less.

[0197] The tensile strength of the floor side portion is usually lower than that of the floor tunnel portion. The portion of the flange 404 that is the floor side portion is formed of steel plate with a strength of, for example, 270 MPa or higher and 780 MPa or lower. The top plate 401, ridge portion 402, and vertical wall 403 included in the floor tunnel portion are formed of steel plate with a strength of, for example, 590 MPa or higher and 1760 MPa or lower. However, if the plate thickness of the floor side portion is smaller than the plate thickness of the floor tunnel portion, the tensile strength of the floor side portion may be the same as that of the floor tunnel portion. On the other hand, if the tensile strength of the floor side portion is lower than that of the floor tunnel portion, the plate thickness of the floor side portion may be the same as that of the floor tunnel portion.

[0198] As described above, the outer edges of each flange 404 are bent toward the top plate 401. When the press-formed product 400 is the front floor, the outer edges of each flange 404 are joined to the side sill, for example, by welding.

[0199] [effect] The press apparatus 100 according to this embodiment includes a first die 10 for the deep drawing process and a second die 20 for the gripping and bending process. With this press apparatus 100, as described below, a press-formed product 400 with a relatively large flange width 404 can be manufactured with good formability from a single material 200, for example, a tailored blank.

[0200] In the deep drawing process using the first mold 10, the intermediate molded product 300 is formed with the material 200 being held between the die flange surface 125 and the holder 13 from the beginning of the molding process. Therefore, tension can be applied to the parts of the material 200 that will become the top plate 301 and vertical walls 303 of the intermediate molded product 300 throughout almost the entire molding process. As a result, even if the vertical walls 303 have height differences in the longitudinal direction of the intermediate molded product 300, the intermediate molded product 300 can be formed while suppressing the occurrence of wrinkles in the top plate 301 and vertical walls 303.

[0201] In the deep drawing process, the portion of the material 200 that will become the top plate 301 of the intermediate molded product 300 is firmly held between the punch top surface 111 and the die bottom surface 121. Therefore, even if, for example, a recessed portion 301a exists on the top plate 301, the top plate 301 can be formed with high precision.

[0202] From the viewpoint of distributing the press load, it is preferable to form the material 200 to the shape of the top plate 401 of the final press-formed product 400 in the deep drawing process. That is, it is preferable that the shape of the top plate 301 of the intermediate molded product 300 formed in the deep drawing process substantially or generally matches the shape of the top plate 401 of the final press-formed product 400. However, it is not always necessary to form the material to the shape of the final top plate 401 in the deep drawing process. Also, the height of the vertical wall 303 of the intermediate molded product 300 formed in the deep drawing process does not have to match the height of the vertical wall 403 of the final press-formed product 400.

[0203] At the top dead center of the second die 20, the end (upper end) of the holder 24 on the die flange surface 234 side is positioned below the punch shoulder 212. At the top dead center of the second die 20, the upper end of the holder 24 is positioned between the punch shoulder 212 and the punch flange surface 215 in the pressing direction of the second die 20. Preferably, the upper end of the holder 24 is positioned in the range where the punch base 214 exists in the pressing direction of the second die 20. Therefore, in the gripping and bending process using the second die 20, the flange 304 of the intermediate molded product 300 is not gripped by the die 23 and the holder 24 in the initial stages of molding. The flange 304 of the intermediate molded product 300 is gripped by the die 23 and the holder 24 from the middle of molding. For example, just before the punch flange surface 215 and the die flange surface 234 clamp the flange 304, the end of the flange 304 in the width direction of the intermediate molded product 300 is grasped by the die flange surface 234 and the holder 24. This allows appropriate tension to be applied to the flange 304. Therefore, the length of the flat portion is less likely to stretch near the portion to which the uneven shape is applied, making it possible to apply an uneven shape to the flange 304 while suppressing the occurrence of wrinkles.

[0204] In the gripping and bending process, the die flange surface 234 and holder 24 begin gripping the flange 304 of the intermediate molded product 300 not at the beginning of the molding process, but midway through. Therefore, compared to the case where the flange 304 is gripped from the beginning of the molding process, excessive tension on the flange 304 can be prevented. Thus, cracking in the flange 304, especially in and near the uneven portion 404a, can be suppressed. Furthermore, by performing the molding process while applying appropriate tension to the flange 304, cracking at the boundary between the metal plates 201 and 202 can be suppressed. In addition, by applying tension evenly to the intermediate molded product 300 from both the left and right sides by the die flange surface 234 and holder 24, the left-right difference in material inflow and outflow during molding can be reduced, and the left-right positional displacement of the boundary between the metal plates 201 and 202 can be suppressed. Moreover, since excessive tension does not act on the vertical wall 303 continuous with the flange 304, cracking in the vertical wall 303 and deterioration of dimensional accuracy due to tension can be suppressed.

[0205] In the gripping and bending process, the uneven shape 215a of the punch flange surface 215 and the uneven shape 235a of the die flange surface 234 form an uneven portion 404a on the flange 304 of the intermediate molded product 300. It is preferable that the die flange surface 234 and the holder 24 begin gripping the flange 304 immediately before the formation of the uneven portion 404a. That is, it is preferable that the flange 304 is gripped by the die flange surface 125 and the holder 24 in the later stages of molding. The timing of gripping the flange 304 can be controlled, for example, by setting the stroke of the holder 24 in the pressing direction. In order to begin gripping the flange 304 immediately before the formation of the uneven portion 404a after the vertical wall 303 has been formed to a certain extent, it is preferable that the stroke of the holder 24 be 5.0 mm or more and 40.0 mm or less. The stroke of the holder 24 is the distance in the pressing direction over which the holder 24 moves while gripping the flange 304 of the intermediate molded product 300 together with the die flange surface 234. The stroke of the holder 24 does not depend on the height of the vertical wall 403 of the press-formed product 400 that is formed in the gripping and bending process.

[0206] In the grip bending process, it is preferable that the vertical wall 303 of the intermediate molded product 300 is formed to the height of the vertical wall 403 of the final press-formed product 400. That is, it is preferable that the forming of the vertical wall 403 of the press-formed product 400 is substantially completed by the grip bending process. However, in the grip bending process, the flange 304 of the intermediate molded product 300 does not need to be completely formed to the shape of the flange 404 of the final press-formed product 400. For example, in the grip bending process, a shape gentler than the final uneven shape can be given to the flange 304 of the intermediate molded product 300. For example, in the grip bending process, an uneven shape with a fillet having a larger radius of curvature compared to the final uneven shape may be given to the flange 304. In this case, the occurrence of cracks in the flange 304 can be suppressed in the grip bending process. The final uneven shape is given to the flange 404 of the press-formed product 400 obtained in the grip bending process in a subsequent process, such as a punching process or a thrust bending process. In other words, in a subsequent process after the gripping and bending process, a recessed shape with a smaller radius of curvature fillet compared to the gripping and bending process is formed on the flange 404. However, in the gripping and bending process, it is preferable to impart a shape to the flange 404 that is somewhat similar to the final recessed shape in order to prevent wrinkles from forming in subsequent processes. For example, it is preferable that the depth (height) of the recesses formed in the gripping and bending process is about the same as the final depth (height) of the recesses.

[0207] In this embodiment, the holder 24 of the second mold 20 includes a bead 241a on the surface 241 on the die flange surface 234 side. In this case, when the intermediate molded product 300 is held between the die flange surface 234 and the holder 24 during the grip bending process, the flange 304 of the intermediate molded product 300 catches on the bead 241a (Figure 10D), making it easier to apply tension to the flange 304. As a result, when an uneven portion 404a is formed on the flange 304 during the grip bending process by the second mold 20, it is possible to suppress the occurrence of wrinkles in and around the uneven portion 404a.

[0208] In this embodiment, the holder 13 of the first mold 10 includes a bead 131a on the surface 131 facing the die flange surface 125. In this case, when the material 200 is sandwiched between the die flange surface 125 and the holder 13 during the deep drawing process, the bead 131a of the holder 13 forms a bead portion 304a on the material 200 and applies tension. This makes it less likely for wrinkles to occur on the top plate 301 and the vertical walls 303 when forming an intermediate molded product 300 in which the vertical walls 303 have height differences in the longitudinal direction. Furthermore, by applying tension to the material 200, it is possible to suppress misalignment of the boundary portion between the metal plates 201 and 202. For example, by hooking the end of the material 200 onto the bead 131a of the holder 13 and applying even tension to the material 200 from both the left and right sides, the left-right difference in material inflow and outflow during molding can be reduced, and misalignment of the left-right position of the boundary portion between the metal plates 201 and 202 can be suppressed.

[0209] It is preferable that the bead 131a of holder 13 and the bead 241a of holder 24 have a stepped shape. The stepped bead 131a can exert a relatively large tension on the material 200, so it can effectively suppress lateral displacement of the material 200 in the deep drawing process. Similarly, the stepped bead 241a can exert a relatively large tension on the intermediate molded product 300. When both the bead 131a of holder 13 and the bead 241a of holder 24 have a stepped shape, the bead portion 304a formed on the flange 304 by the bead 131a in the deep drawing process is more likely to catch on the bead 241a in the gripping and bending process.

[0210] When both the bead 131a of holder 13 and the bead 241a of holder 24 are stepped, the step height of the beads 131a and 241a is preferably 5.0 mm or more and 15.0 mm or less. If the step height of the beads 131a and 241a is too small, the tension applied by the beads 131a and 241a will be insufficient, which may cause misalignment at the boundary between the metal sheets 201 and 202 during the deep drawing process, and may also cause wrinkles to form on the flange 304 during the grip bending process. On the other hand, if the step height of the beads 131a and 241a is too large, the tension applied by the beads 131a and 241a will increase, which may cause cracking at the boundary between the metal sheets 201 and 202, and fracture at the ridges 302 and vertical walls 303.

[0211] In this embodiment, it is preferable that the wire length L12 of the first mold 10 from the center line C1 of the punch 11 to the bead 131a of the holder 13 is substantially equal to the wire length L22 of the second mold 20 from the center line C2 of the punch 21 to the bead 241a of the holder 24. In this case, when the intermediate molded product 300 obtained in the deep drawing process using the first mold 10 is placed in the second mold 20, the bead portion 304a formed on the flange 304 by the bead 131a of the holder 13 will be positioned at the location of the bead 241a of the holder 24. As a result, in the gripping and bending process, the bead portion 304a of the flange 304 is more likely to catch on the bead 241a of the holder 24, making it easier to apply more tension to the flange 304. Furthermore, in the gripping and bending process, the bead portion 304a of the flange 304 is not crushed by the die 23 and the holder 24, so no extra tension is applied to the flange 304 due to deformation of the bead portion 304a. As a result, the occurrence of cracks at the boundary portion of the metal plates 201 and 202 is more easily suppressed.

[0212] In this embodiment, it is preferable that the wire length L11 of the first die 10, from the center line C1 of the punch 11 to the end of the punch base 114 on the punch flange surface 115 side, is substantially equal to the wire length L21 of the second die 20, from the center line C2 of the punch 21 to the end of the punch base 214 on the punch flange surface 215 side. This makes it less likely for material to flow in from the flange 304 of the intermediate molded product 300 and out to the flange 304 when the gripping and bending process is performed by the second die 20 after the deep drawing process by the first die 10. As a result, for example, changes in stress due to the inflow or outflow of material are suppressed in the vertical wall 303 continuous with the flange 304. Thus, the dimensional accuracy of the press-formed product 400 can be ensured. Furthermore, by suppressing the inflow of material into the flange 304 and the outflow of material from the flange 304, displacement of the intermediate molded product 300 is less likely to occur. Therefore, when an uneven portion 404a is formed on the flange 304 during the grip bending process, it is possible to prevent indentations from remaining on the flange surfaces 215, 234 and wrinkles from forming in the uneven portion 404a and its vicinity. In addition, since the boundary portion of the metal plates 201, 202 does not substantially move from its position in the deep drawing process during the grip bending process, cracking at the boundary portion of the metal plates 201, 202 can be suppressed.

[0213] By making the wire length L21 of the second die 20 substantially the same as the wire length L11 of the first die 10, the intermediate molded product 300 can be bent by the punch base 214 and die shoulder 233 at the same position as during the deep drawing process using the first die 10 during the gripping and bending process using the second die 20. In this case, unnecessary tensile or compressive deformation of the intermediate molded product 300 is less likely to occur at and near the die shoulder 233. Therefore, dimensional changes of the flange 304 near the die shoulder 233 can be suppressed. As a result, opening or closing of the flange 404 in the press-formed product 400 after the deep drawing process is suppressed. Furthermore, wall opening or closing in the press-formed product 400 can also be suppressed. Therefore, the dimensional accuracy of the press-formed product 400 can be improved.

[0214] In this embodiment, when the first mold 10 is viewed in cross-section, the die flange surface 125 may be inclined with respect to the horizontal plane such that the inner end is located closer to the die bottom surface 121 in the pressing direction compared to the outer end in the width direction. That is, it is preferable that the angle α of the die flange surface 125 with respect to the horizontal plane is greater than 0°. In this case, the die shoulder 124 can be formed relatively gently, so that in the deep drawing process using the first mold 10, when material flows from the die flange surface 125 side through the die shoulder 124 to the die side surface 123 side, the inflow resistance at the die shoulder 124 is reduced. As a result, deformation of the material 200 at and near the die shoulder 124 is reduced, and cracking at the vertical wall 303 of the intermediate molded product 300 and at the boundary portion of the metal plates 201 and 202 can be suppressed. Furthermore, by reducing the deformation of the material 200 at and near the die shoulder 124, deterioration of the dimensional accuracy of the vertical wall 303 can also be suppressed.

[0215] The angle α of the die flange surface 125 with respect to the horizontal plane is preferably 20° or less. If the angle α exceeds 20°, the flange 304 of the intermediate molded product 300 obtained in the deep drawing process will be significantly downward-facing, which may make it difficult to stably place the intermediate molded product 300 on the punch 21 of the second mold 20 in the subsequent gripping and bending process.

[0216] In this embodiment, it is preferable that the die shoulder 124 of the first mold 10 has a radius of curvature of 25.0 mm or more. This makes the die shoulder 124 relatively gentle, so that in the deep drawing process, when the material 200 flows from the die flange surface 125 side through the die shoulder 124 to the die side surface 123 side, deformation of the die shoulder 124 and its vicinity can be reduced. This improves the dimensional accuracy of the vertical wall 303 of the intermediate molded product 300 obtained in the deep drawing process, and also suppresses cracking in the vertical wall 303.

[0217] In this embodiment, a bulge 113a is provided on the punch side surface 113 of the first mold 10. The bulge 113a bulges outward in the width direction of the first mold 10, that is, in the opposite direction to the wall warping that is likely to occur in the deep drawing process. As a result, when forming the intermediate molded product 300 from the material 200 in the deep drawing process, the bulge 113a of the punch side surface 113 causes the vertical wall 303 to bulge in the opposite direction to the wall warping, thereby suppressing wall warping. That is, when the intermediate molded product 300 is removed from the first mold 10, if the vertical wall 303 attempts to deform inward due to wall warping, the deformation of the wall warping is canceled out by the bulge formed by the bulge 113a of the punch side surface 113. As a result, a vertical wall 303 with no or minimal wall warping can be obtained.

[0218] In this embodiment, the length of the punch top surface 111 in the width direction of the first mold 10 is greater than the length of the punch top surface 211 in the width direction of the second mold 20. In this case, when the intermediate molded product 300 obtained in the deep drawing process by the first mold 10 is placed in the second mold 20, the ridge portion 302 of the intermediate molded product 300 will be located outside the punch shoulder 212 in the width direction of the second mold 20. In the gripping and bending process by the second mold 20, the ridge portion 302 of the intermediate molded product 300 is bent back near the punch shoulder 212 by the punch 21 and die 23. In the bent portion, tensile stress is generated on the inside of the intermediate molded product 300, and compressive stress is generated on the outside of the intermediate molded product 300. On the other hand, at the position of the punch shoulder 212, compressive stress is generated on the inside of the intermediate molded product 300 due to bending by the punch shoulder 212, and tensile stress is generated on the outside of the intermediate molded product 300. During demolding, a wall-opening moment is generated by the reversal stress in the portion bent by the punch shoulder 212. However, a wall-closing moment is generated by the reversal stress in the ridge portion 302 that is bent back near the punch shoulder 212, and the wall-closing moment cancels out the wall-opening moment. Therefore, the wall-opening moment can be reduced in the press-formed product 400 removed from the second mold 20, and the springback of the wall opening can be reduced. Consequently, the dimensional accuracy of the press-formed product 400 can be improved.

[0219] If the length of the punch top surface 111 in the width direction of the first die 10 is greater than the length of the punch top surface 211 in the width direction of the second die 20, and the line length L11 of the first die 10 from the center line C1 of the punch 11 to the end of the punch base 114 is substantially equal to the line length L21 of the second die 20 from the center line C2 of the punch 21 to the end of the punch base 214, then the height H of the punch side surface 113 of the first die 10 is ps1 This inevitably means that the height H of the punch side 213 of the second mold 20 ps2 It becomes smaller than that. Punch side height H 113 ps1 When this value is small, the deformation that occurs in the material 200 during the deep drawing process by the first mold 10 is also small. Therefore, the occurrence of cracks and springback can be suppressed during the deep drawing process.

[0220] In this embodiment, the punch top surface 111 of the first mold 10 includes a convex surface 111b adjacent to the punch shoulder 112. This convex surface 111b forms a protrusion 301b on the top plate 301 of the intermediate molded product 300 during the deep drawing process by the first mold 10. During the gripping and bending process by the second mold 20, the punch 21 and die 23 bend the protrusion 301b of the intermediate molded product 300 back in the vicinity of the punch shoulder 212. Tensile stress is generated on the inside of the intermediate molded product 300 and compressive stress is generated on the outside of the intermediate molded product 300 at the back-bent protrusion 301b. On the other hand, at the position of the punch shoulder 212, compressive stress is generated on the inside of the intermediate molded product 300 and tensile stress is generated on the outside of the intermediate molded product 300 due to bending by the punch shoulder 212. During demolding, a wall-opening moment is generated by the reversal stress in the portion bent by the punch shoulder 212. However, a wall-closing moment is generated by the reversal stress in the unbent protrusion 301b, and the wall-closing moment cancels out the wall-opening moment. Therefore, the wall-opening moment can be further reduced in the press-formed product 400 removed from the second mold 20, and the springback of the wall opening can be further reduced. Consequently, the dimensional accuracy of the press-formed product 400 can be further improved.

[0221] In this embodiment, the die flange surface 234 of the second die 20 includes a concave surface 234b adjacent to the die shoulder 233. Due to this concave surface 234b, a protrusion 404b is formed on the flange 404 of the press-formed product 400 near the die shoulder 233 during the gripping and bending process by the second die 20. In this case, during the subsequent punching or punching process, the protrusion 404b of the press-formed product 400 is bent back by the third die 30 or the fourth die 40. When the protrusion 404b is bent back, compressive stress is generated on the outside of the press-formed product 400 and tensile stress is generated on the inside of the press-formed product 400. This generates a moment (downward moment) that causes the flange 404 of the press-formed product 400 to open when demolded. Therefore, it is possible to suppress springback that would cause the flange 404 to face upward after demolding.

[0222] As shown in Figure 14, the die flange surface 234 of the second die 20 may include a convex surface 234d instead of a concave surface 234b. The convex surface 234d is positioned adjacent to the die shoulder 233 and protrudes outward from the die 23. In this case, during the gripping and bending process by the second die 20, a recess is formed in the flange 404 of the press-formed product 400 near the die shoulder 233. The recess in the press-formed product 400 is bent back in the third die 30 or fourth die 40 during the punching or punch-bending process. The bending back of the recess generates tensile stress on the outside of the press-formed product 400 and compressive stress on the inside of the press-formed product 400. As a result, a moment (upward moment) is generated in the direction that closes the flange 404 of the press-formed product 400 during demolding. Therefore, springback that causes the flange 404 to point downward after demolding can be suppressed.

[0223] In this way, by providing a concave surface 234b or a convex surface 234d near the die shoulder 233 on the die flange surface 234 of the second mold 20, the opening and closing of the flange 404 can be adjusted. As a result, a press-formed product 400 with good dimensional accuracy can be obtained. However, if it has been confirmed that the flange 404 does not spring back at all or almost at all in prototypes during the production preparation stage, for example, the concave surface 234b and convex surface 234d on the die flange surface 234 are unnecessary.

[0224] In this embodiment, a bulge 213a is provided on the punch side surface 213 of the second die 20. The bulge 213a bulges outward in the width direction of the second die 20, that is, in the opposite direction to the wall curvature that may occur in each process. In the gripping and bending process by the second die 20, a vertical wall 403 can be obtained on the punch side surface 213 that bulges outward on the opposite side of the wall curvature due to the bulge 213a. In this case, when demolding, if the vertical wall 403 that bulges outward on the press-formed product 400 attempts to deform inward, the deformation of the wall curvature is offset by the bulge of the vertical wall 403. Therefore, wall curvature can be reduced. If bulging remains on the vertical wall 403 after demolding, the bulged vertical wall 403 can be bent back, for example, in a punching process or a punch bending process. This reduces wall opening and wall curvature, and a press-formed product 400 with good dimensional accuracy can be obtained.

[0225] In this embodiment, press forming is performed using a material 200 that includes metal sheets 201 and 202 with different thicknesses. Furthermore, in this embodiment, since the step between metal sheet 201 and metal sheet 202 is formed toward the die 12 side, a step 125a corresponding to the step in the material 200 is provided on the die flange surface 125 of the first mold 10.

[0226] Generally, in a deep drawing process, the boundary between the punch 11 and the holder 13 is located near the R-end on the die flange surface 125 side of the die shoulder 124. If the step 125a of the first die 10 is located at the boundary between the metal sheets 201 and 202 at the end of the deep drawing process, then at the bottom dead center of the first die 10, the boundary between the metal sheets 201 and 202, i.e., the step of the material 200, is located at the step 125a of the first die 10, and the entire material 200 is pressed by the first die 10. However, if the step 125a of the first die 10 is located at the boundary between the metal sheets 201 and 202 at the end of the deep drawing process, as shown in Figure 15, during the deep drawing process, because the thickness of the metal sheet 201 is greater than the thickness of the metal sheet 202, the metal sheet 201 is held between the die 12 and the holder 13, while the metal sheet 202 is not held between them. Therefore, wrinkles may form in material 200.

[0227] On the other hand, as shown in Figure 16A, if the step 125a of the first die 10 is located at the boundary between the metal sheets 201 and 202 at the start of the deep drawing process, the entire thin metal sheet 202 is held between the die 12 and the holder 13 when the die 12 begins to press down on the material 200 on the holder 13. However, in this case, as the forming progresses, the material 200 is pulled towards the punch 11, and at the bottom dead center of the first die 10, as shown in Figure 16B, the die 12 and the holder 13 cannot hold the metal sheet 202 near the step 125a. Therefore, wrinkles may form in the material 200.

[0228] In contrast, in this embodiment, the first mold 10 is configured to hold the material 200 between the die 12 and the holder 13 at the beginning of the deep drawing process, to proceed with forming while holding the material 200, and to hold the entire material 200 between the punch 11 and the holder 13 and the die 12 at the bottom dead center. That is, in a cross-sectional view of the first mold 10, the line length L13 from the center line C1 of the punch 11 to the boundary between the punch 11 and the holder 13 is greater than or equal to the line length L14 from the center line C1 of the die 12 to the step 125a. The line length L13 may be longer than the line length L14. In other words, the boundary between the punch 11 and the holder 13 may be located outside the step 125a of the die 12 in the width direction of the first mold 10. The step 125a of the die 12 is located at the boundary portion of the metal plates 201 and 202 at the end of the deep drawing process. As a result, at the start of the deep drawing process, the entire portion of the material 200 that is on the holder 13 can be held down by the die 12 and the holder 13, and at the end of the deep drawing process, the entire material 200 can be held between the punch 11, die 12, and holder 13. Therefore, it is possible to suppress the occurrence of wrinkles in the material 200 during the deep drawing process using the first mold 10.

[0229] In the deep drawing process, when forming the material 200 with the step facing the punch 11, the step 125a for receiving the step of the material 200 is provided on the punch flange surface 115. That is, the step 125a is formed on the punch flange surface 115 such that the clearance between the punch 11 and the die 12 is larger on the inside than on the outside in the width direction of the first mold 10. Similarly, in the gripping and bending process, when forming the intermediate molded product 300 with the step facing the punch 11, the step 234c for receiving the step of the intermediate molded product 300 can be provided on the punch flange surface 215 instead of the die flange surface 234. If the thickness of the metal plates 201 and 201 is the same and no steps occur on the surface of the material 200 and the intermediate molded product 300, it is not necessary to provide steps 125a and 234c on the first mold 10 and the second mold 20.

[0230] In this embodiment, it is preferable that the wire length L31 of the third die 30 from the center line C3 of the punch 31 to the end of the punch base 314 on the punch flange surface 315 side is substantially equal to the wire length L21 of the second die 20 from the center line C2 of the punch 21 to the end of the punch base 214 on the punch flange surface 215 side. This makes it difficult for material to flow in from the punch flange surface 315 side to the punch base 314 side and for material to flow out from the punch base 314 side to the punch flange surface 315 side during the punching process using the third die 30. As a result, changes in stress associated with the inflow or outflow of material are suppressed in the press-formed product 400 subjected to the punching process. Thus, deterioration of the dimensional accuracy of the press-formed product 400 can be prevented. Furthermore, when the press-formed product 400 is held by the punch 31 and the pad 32, the boundary portion of the metal plates 201 and 202 does not substantially move from its position during the gripping and bending process by the second die 20, thus suppressing cracking, especially at the boundary portion of the metal plates 201 and 202.

[0231] In this embodiment, it is preferable that the wire length L41 of the fourth die 40 from the center line C4 of the holder 41 to the end of the holder base 414 on the holder flange surface 415 side is substantially equal to the wire length L21 of the second die 20 from the center line C2 of the punch 21 to the end of the punch base 214 on the punch flange surface 215 side. This makes it less likely for material to flow from the holder flange surface 415 side to the holder base 414 side and for material to flow from the holder base 414 side to the holder flange surface 415 side during the punch bending process using the fourth die 40. As a result, changes in stress due to material inflow or outflow are suppressed in the press-formed product 400 subjected to the punch bending process. Thus, deterioration of the dimensional accuracy of the press-formed product 400 can be prevented. Furthermore, when the press-formed product 400 is held by the holder 41 and the die 42, the boundary portion of the metal plates 201 and 202 does not substantially move from its position in the previous process, thus suppressing cracking, especially at the boundary portion of the metal plates 201 and 202.

[0232] In this embodiment, after the deep drawing process using the first die 10 and the gripping and bending process using the second die 20, a punching process using the third die 30 and a thrust bending process using the fourth die 40 are performed. The punching and thrust bending processes allow the press-formed product 400 to be shaped into the final product. However, the punching and / or thrust bending processes can be omitted in the manufacturing of the press-formed product 400. In this case, the press apparatus 100 may not be equipped with one or both of the third die 30 and the fourth die 40.

[0233] While embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible as long as they do not deviate from its spirit. [Explanation of Symbols]

[0234] 100: Pressing device 10: First mold 11: Punch (First punch) 111: Punch top surface (first punch top surface) 111b: Convex 112: Punching shoulder (first punching shoulder) 113: Punch side (First punch side) 113a:bulge 114: Punch base (first punch base) 115: Punch flange surface (first punch flange surface) 12: Die (First Die) 121: Die bottom surface (first die bottom surface) 122: Die bottom edge (first die bottom edge) 123: Die side (first die side) 124: First shoulder 125: Die flange surface (first die flange surface) 125a: Step 13: Holder (1st Holder) 131: Surface 131a: Bead (First bead) 20: Second mold 21: Punch (Second punch) 211: Punch top surface (Second punch top surface) 212: Punch shoulder (Second punch shoulder) 213: Punch side surface (Second punch side surface) 213a: Bulge 214: Punch base (Second punch base) 215: Punch flange surface (Second punch flange surface) 215a: Concavo-convex shape 22: Pad (First pad) 23: Die (Second die) 231: Die bottom edge (Second die bottom edge) 232: Die side surface (Second die side surface) 233: Die shoulder (Second die shoulder) 234: Die flange surface (Second die flange surface) 234b: Concave surface 234d: Convex surface 24: Holder (Second holder) 241: Surface 241a: Bead (Second bead) 30: Third mold 31: Punch (Third punch) 311: Punch top surface (Third punch top surface) 312: Punch shoulder (Third punch shoulder) 313: Punch side surface (Third punch side surface) 314: Punch base (Third punch base) 315: Punch flange surface (Third punch flange surface) 32: Pad (Second pad) 321: Pad bottom surface 322: Pad bottom edge 323: Pad side surface 324: Pad shoulder 325: Pad flange surface 33: Die (Third die) 40: Fourth mold 41: Holder (Third holder) 411: Holder top surface 412: Holder shoulder 413: Holder side surface 414: Holder base 415: Holder flange surface 42: Die (Fourth Die) 421: Die Bottom Surface (Fourth Die Bottom Surface) 422: Die Bottom Edge Portion (Fourth Die Bottom Edge Portion) 423: Die Side Surface (Fourth Die Side Surface) 424: Die Shoulder (Fourth Die Shoulder) 425: Die Flange Surface (Fourth Die Flange Surface) 43: Punch (Fourth Punch) 200: Material 201, 202: Metal Plate 300: Intermediate Formed Product 301: Top Plate 303: Vertical Wall 304: Flange 400: Press Formed Product 401: Top Plate 403: Vertical Wall 404: Flange

Claims

1. A press device, A first mold including a first punch, a first die, and a first holder, A second mold including a second punch, a first pad, a second die, and a second holder, A third mold including a third punch, a second pad, and a third die, Equipped with, The first punch includes a first punch top surface, a first punch shoulder continuous with the first punch top surface, a first punch side surface continuous with the first punch shoulder and having a height difference in the longitudinal direction of the first die, a first punch base continuous with the first punch side surface on the opposite side of the first punch shoulder, and a first punch flange surface continuous with the first punch base and extending outward in the width direction of the first die from the first punch base. The first die includes a first die bottom surface having a shape corresponding to the top surface of the first punch, facing the top surface of the first punch, a first die bottom edge continuous with the first die bottom surface and having a shape corresponding to the shoulder of the first punch, a first die side continuous with the first die bottom edge and having a shape corresponding to the side surface of the first punch, a first die shoulder on the opposite side of the first die bottom edge and continuous with the first die side, and having a shape corresponding to the base of the first punch, and a first die flange surface continuous with the first die shoulder, extending outward from the first die shoulder in the width direction of the first mold, and facing the first punch flange surface and the first holder. The second punch includes a second punch top surface facing the first pad, a second punch shoulder continuous with the second punch top surface, a second punch side surface continuous with the second punch shoulder, a second punch base continuous with the second punch side surface on the opposite side of the second punch shoulder, and a second punch flange surface continuous with the second punch base, extending outward from the second punch base in the width direction of the second die, and having at least a portion of an uneven shape. The second die includes a second die bottom edge having a shape corresponding to the second punch shoulder, a second die side having a shape corresponding to the second punch side, a second die shoulder having a shape corresponding to the second punch base, and being continuous with the second die side on the opposite side of the second die bottom edge. At the top dead center of the second die, the end of the second holder on the second die flange side is located between the second punch shoulder and the second punch flange surface in the pressing direction of the second die. The third punch includes a third punch top surface, a third punch shoulder continuous with the third punch top surface, a third punch side continuous with the third punch shoulder, a third punch base continuous with the third punch side on the opposite side of the third punch shoulder, and a third punch flange surface continuous with the third punch base and extending outward in the width direction from the third punch base to the third die. The second pad has a shape corresponding to the top surface of the third punch and includes a pad bottom surface facing the top surface of the third punch, a pad bottom edge continuous with the pad bottom surface and having a shape corresponding to the shoulder of the third punch, a pad side continuous with the pad bottom edge and having a shape corresponding to the side surface of the third punch, a pad shoulder on the opposite side of the pad bottom edge and continuous with the pad side and having a shape corresponding to the base of the third punch, and a pad flange surface continuous with the pad shoulder and extending outward from the pad shoulder in the width direction of the third die and facing the flange surface of the third punch. A press device wherein the third die is positioned outside the third punch and the second pad in the width direction of the third mold.

2. A press apparatus according to claim 1, A press apparatus in which, at the top dead center of the second die, the end of the second holder on the second die flange surface side is located in the range where the second punch base exists in the pressing direction.

3. A press apparatus according to claim 1, The second holder is a press device that includes a bead formed on the surface of the second die flange side.

4. A press apparatus according to claim 1, The first holder is a press device that includes a bead formed on the surface of the first die flange side.

5. A press apparatus according to claim 1, The first holder includes a first bead formed on the surface of the first die flange side, The second holder includes a second bead formed on the surface of the second die flange side, A press apparatus in which, when the first die is viewed in cross-section, the length of the line along the surface of the first punch and the surface of the first holder from the center of the first punch in the width direction of the first die to the first bead is equal to the length of the line along the surface of the second punch and the surface of the second holder from the center of the second punch in the width direction of the second die to the second bead, when the second die is viewed in cross-section.

6. A press apparatus according to claim 1, A press apparatus in which, when the first die is viewed in cross-section, the linear length of the surface of the first punch from the center of the first punch in the width direction of the first die to the end of the first punch base on the first punch flange side is equal to the linear length of the surface of the second punch from the center of the second punch in the width direction of the second die to the end of the second punch base on the second punch flange side, when the second die is viewed in cross-section.

7. A press apparatus according to claim 1, A press apparatus in which, when the first die is viewed in cross-section, the first die flange surface is inclined with respect to the horizontal plane such that, in the width direction of the first die, the inner end is located closer to the bottom surface of the first die than the outer end.

8. A press apparatus according to claim 1, A press apparatus in which the side surface of the first punch includes a bulge that protrudes outward in the width direction of the first die.

9. A press apparatus according to claim 1, A press apparatus in which the length of the top surface of the first punch in the width direction of the first die is greater than the length of the top surface of the second punch in the width direction of the second die.

10. A press apparatus according to claim 1, A press apparatus in which the top surface of the first punch is positioned adjacent to the shoulder of the first punch and includes a convex surface that protrudes outward from the first punch.

11. A press apparatus according to claim 1, A press apparatus in which the second die flange surface is positioned adjacent to the second die shoulder and includes a convex surface projecting outward from the second die, or a concave surface positioned adjacent to the second die shoulder and recessed inward from the second die.

12. A press apparatus according to claim 1, A press apparatus in which the side surface of the second punch includes a bulge that protrudes outward in the width direction of the second die.

13. A press apparatus according to claim 1, A step is provided on the shoulder side of the first die flange surface such that the clearance between the first punch and the first die is larger on the inside than on the outside in the width direction of the first mold. A press apparatus in which, when the first die is viewed in cross-section, the linear length of the surface of the first punch from the center of the first punch in the width direction of the first die to the boundary between the first punch and the first holder is greater than or equal to the linear length of the surface of the first die from the center of the first die in the width direction of the first die to the step.

14. A press apparatus according to claim 1, A press apparatus in which, when the second die is viewed in cross-section, the linear length of the surface of the second punch from the center of the second punch in the width direction of the second die to the end of the second punch base on the second punch flange side is equal to the linear length of the surface of the third punch from the center of the third punch in the width direction of the third die to the end of the third punch base on the third punch flange side, when the third die is viewed in cross-section.

15. The press apparatus according to claim 1, further, A fourth mold including a fourth punch, a third holder, and a fourth die, Equipped with, The third holder includes a holder top surface, a holder shoulder continuous with the holder top surface, a holder side continuous with the holder shoulder, a holder base continuous with the holder side on the opposite side of the holder shoulder, and a holder flange surface continuous with the holder base and extending outward in the width direction from the holder base to the fourth mold. The fourth die includes a fourth die bottom surface having a shape corresponding to the holder top surface, facing the holder top surface, a fourth die bottom edge having a shape corresponding to the holder shoulder, a fourth die side having a shape corresponding to the holder side surface, a fourth die shoulder having a shape corresponding to the holder base, facing the holder flange surface, and extending outward from the fourth die shoulder in the width direction of the fourth die. A press device wherein the fourth punch is positioned outside the third holder and the fourth die in the width direction of the fourth mold.

16. A press apparatus according to claim 15, A press apparatus in which, when the second die is viewed in cross-section, the linear length of the surface of the second punch from the center of the second punch in the width direction of the second die to the end of the second punch base on the second punch flange side is equal to the linear length of the surface of the third holder from the center of the third holder in the width direction of the fourth die to the end of the holder base on the holder flange side, when the fourth die is viewed in cross-section.

17. A method for manufacturing press-formed products, The process of preparing a material including multiple metal plates joined together, A first step involves using a first mold, which includes a first punch, a first die, and a first holder, to press-form the material into an intermediate molded product. A second step involves press-forming the intermediate molded product using a second mold comprising a second punch, a first pad, a second die, and a second holder. A third step involves trimming the press-formed product obtained in the second step using a third mold including a third punch, a second pad, and a third die. Equipped with, The aforementioned intermediate molded product is The tabletop and A vertical wall connected to the top plate and having a height difference in the longitudinal direction of the intermediate molded product, A flange connected to the vertical wall on the opposite side of the top plate, extending outward from the vertical wall in the width direction of the intermediate molded product, Including, The first step is, A step of clamping the material between the first die and the first holder, A step of forming the top plate and vertical wall of the intermediate molded product by bringing the first punch and the first die relatively close together while the material is held between the first die and the first holder, Includes, The second step is, A step of sandwiching the top plate of the intermediate molded product between the second punch and the first pad, A step of starting molding by the second punch and the second die by bringing the second punch and the second die closer together, while the top plate is held between the second punch and the first pad, and the end of the intermediate molded product in the width direction is not held between the second die and the second holder, Before the flange of the intermediate molded product is formed by the second punch and the second die, which are relatively close to each other, the process involves clamping the end of the intermediate molded product between the second die and the second holder, The process involves forming the flange with the second punch and the second die while tension is applied to the flange by clamping the end of the intermediate molded product between the second die and the second holder, thereby forming an uneven shape on the flange, Includes, A manufacturing method comprising the third step, in which the end of the flange is cut by the third die and the third punch while the press-formed product is held between the third punch and the second pad.

18. A manufacturing method according to claim 17, A manufacturing method wherein, in the second step, the end portion of the intermediate molded product is held between the second die and the second holder immediately before the formation of the uneven shape of the flange by the second punch and the second die begins.

Images