Method for forming overlapping members and overlapping members press-formed by the method

Abstract

This prevents separation of the plate materials of a joined blank in an area that is not clamped by a pad die and a punch die when press-forming a superposed member from a joined blank. When a superposed member is formed integrally by press-forming from a joined blank in which a first plate material, which is a metal plate material constituting a main body component, and a second plate material, which is a metal plate material constituting a reinforcing component, are overlapped on the inside of a hat-shaped main body component with a U-shaped or L-shaped cross-sectional reinforcing component, the linear length of the area corresponding to the curved portion and vertical wall portion of the second plate material in a cross section perpendicular to the bending ridge line of the superposed member is set to be equal to or longer than the linear length from the end of the area corresponding to the top plate portion of the first plate material to the contact position with the shoulder of the die mold when the end of the first plate material comes into contact with a mold surface extending from the flange forming surface of the punch mold during press-forming of the superposed member using a pair of punch and die molds.

Description

[Technical Field]

[0001] The present invention relates to a method for press-forming a laminated member from a joined blank formed by overlapping and joining metal plate materials, and to a laminated member press-formed by the method. The present invention also relates to a method for manufacturing an automobile part including the laminated member. [Background technology]

[0002] Automotive structural components are required to suppress deformation of the vehicle body during a collision and to protect the interior space of the vehicle by absorbing collision energy. In recent years, efforts have been made to increase the strength and performance of structural components in order to achieve even better collision safety.

[0003] Many frame components are formed from elongated members with a hat-shaped or U-shaped cross section. One way to improve the performance of such components is to overlap and join reinforcing components to the outside or inside of the main body component.

[0004] Generally, members having such an overlapping structure are manufactured by press-forming the main body part and the reinforcing part separately from metal plates, then holding them in an overlapping state and joining them by various methods such as spot welding.In addition, a method has been proposed in which metal plates are overlapped in advance before forming the two parts, and then both parts are simultaneously press-formed from the overlapping metal plates to manufacture them as an integrated unit.

[0005] For example, Patent Document 1 describes a method of overlapping a metal plate material that will become a main component and a metal plate material that will become a reinforcing component, and then bulging-forming an overlapping member from them. In this method, a second plate material that is smaller in area and thicker than the first plate material is joined to the back surface of the first plate material in the bulging direction. Then, with the outer edge of the first plate material restrained, the main component is bulged from the first plate material, while the reinforcing component is formed from the second plate material without restraint. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-192245 Summary of the Invention [Problem to be solved by the invention]

[0007] In the method described in Patent Document 1, when press-forming overlapping members with hat-shaped or U-shaped cross sections to form a frame part, the region corresponding to the top plate of the plate material is curved during forming of the main body part, which poses a problem that the shape of the overlapping members deviates significantly from the correct dimensions due to springback after demolding.

[0008] One method for solving the above problem is a press-forming method in which a region of a sheet material corresponding to the top plate is clamped between a pad die and a punch die, while the punch die and die are used to bulge and form a main body component, thereby suppressing curvature in the region corresponding to the top plate. However, when this press-forming method is used to integrally mold overlapping components with hat-shaped or U-shaped cross sections, the region corresponding to the top plate is clamped between the pad die and the punch die. However, in the regions corresponding to the bend ridges and vertical walls that are not clamped between the pad die and the punch die, separation between the first sheet material constituting the main body component and the second sheet material constituting the reinforcing component may occur during molding. In this case, a gap may form between the main body component and the reinforcing component after demolding, which can reduce the performance of the overlapping components and hinder assembly.

[0009] Therefore, an object of the present invention is to provide a molding method for integrally press-molding an overlapping member composed of a main body part having a hat-shaped or U-shaped cross section and a reinforcing part having a U-shaped or L-shaped cross section, which solves the above-mentioned problems. It is also an object of the present invention to provide an overlapping member press-molded by this molding method. It is also an object of the present invention to provide a method for manufacturing an automotive part including this overlapping member. [Means for solving the problem]

[0010] To solve the above-mentioned problems, the inventors conducted the following study. First, a metal plate material constituting a main body part with a hat-shaped or U-shaped cross-section was designated as the first plate material, and a metal plate material constituting a reinforcing part with a U-shaped or L-shaped cross-section was designated as the second plate material. A region of the first plate material corresponding to the top plate portion of the main body part and a region of the second plate material corresponding to the top plate portion of the reinforcing part were clamped between a pad mold and a punch mold. Then, the first and second plate materials were press-formed using a punch mold and a die mold to integrally form a laminated member consisting of the main body part and the reinforcing part. The linear lengths of the first and second plate materials during this forming process were varied, and the deflection of each plate material during forming in a cross section perpendicular to the bending ridge of the laminated member was calculated. After careful study of the results, the inventors discovered the following two types of modes in which separation of the two plate materials occurs.

[0011] In the first form, the main body part has a hat-shaped cross section having a top plate part, vertical wall parts, and flange parts connected to each other by a bending ridge part, and the reinforcing part has a U-shaped or L-shaped cross section having a top plate part and vertical wall parts connected to each other by the bending ridge part. During the forming of the overlapping member until the end of the first plate material contacts the mold surface that is an extension of the flange-forming surface of the punch mold that forms the flange part, the linear length of the region of the second plate material that is not clamped during forming, i.e., the total linear length corresponding to the bending ridge part and vertical wall parts after forming, is shorter than the linear length from the end of the region of the first plate material that corresponds to the top plate part to the contact position with the shoulder of the die mold.

[0012] In a second embodiment, the main body component has a U-shaped cross section having a top plate and a vertical wall connected to each other at a bending ridge, and the reinforcing component has a U-shaped or L-shaped cross section having a top plate and a vertical wall connected to each other at a bending ridge. During molding of the overlapping member until the inclination angle of the first plate at the position where the shoulder of the die mold and the first plate contact each other matches the inclination angle of the molding surface of the vertical wall of the die mold, the linear length of the region of the second plate that is not clamped during molding, i.e., the total linear length corresponding to the bending ridge and vertical wall after molding, becomes shorter than the linear length from the end of the region of the first plate that corresponds to the top plate to the position where the first plate contacts the shoulder of the die mold.

[0013] In order to solve the above-mentioned problems, the present invention has the following configuration. First, let X be the ratio of the line length corresponding to the vertical wall portion of the second plate material after forming to the line length corresponding to the vertical wall portion of the first plate material after forming in a cross section perpendicular to the bending ridge of the overlapping member. Attention was focused on the condition that the rising angle Y of the vertical wall portion relative to the top plate portion of the overlapping member must satisfy. Then, the conditional formula was derived for each of the first and second embodiments. The method for deriving the conditional formula will be described below with reference to FIGS. 5 to 11. Note that even if the rising angle Y of the vertical wall portion relative to the top plate portion of the overlapping member is significantly inclined from 90 degrees, in this specification, the wall portion connected to the top plate portion via the bending ridge portion will be referred to as the "vertical wall portion" for convenience.

[0014] <First Form> 5 shows a cross-sectional schematic diagram of the moment when the die surface, which is an extension of the flange forming surface of the punch die T1, comes into contact with the end of the first plate material L constituting the main body component in the first embodiment. At this time, the first plate material L, which is the metal plate material constituting the main body component, and the second plate material P, which is the metal plate material constituting the reinforcing component, are sandwiched between the punch die T1 and the pad die T3 in a region corresponding to the top plate portion. The end of the first plate material L is in contact with the die surface, which is an extension of the flange forming surface of the punch die T1.

[0015] The height of the main body part is L H and the rising angle of the vertical wall portion relative to the top plate portion of the overlapping member is Y, the distance L0 in FIG. 5 can be expressed by the following formula (3).

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[0016] The position where the shoulder of the die mold T2 and the first plate material L first come into contact is defined as the origin O, and the horizontal distance from the origin O toward the center of the part is defined as z. Then, the vertical deflection f(z) of the first plate material L and the second plate material P at the distance z can be expressed by the following formula (4) using the distances L0 and C1.

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[0017] Here, C1 is a coefficient that reflects the magnitude of the deflection deformation of the first plate material L and the second plate material P. In this embodiment, it is a value that represents the deflection deformation at the moment when the die surface, which is an extension of the flange portion forming surface of the punch die T1, comes into contact with the end of the first plate material L. The process of deriving C1 will be explained below.

[0018] Figure 6 shows a cross-sectional schematic diagram of the linear length of a metal plate per unit length in the horizontal direction when it is bent. The bent plate has a curved shape. However, it can be approximated as a straight line per unit length. Therefore, using the vertical deflection f(i) of the first and second plates at z = i and the vertical deflection f(i+1) of the first and second plates at z = i + 1, the line length L of the plate per unit length in the horizontal direction is i can be expressed by the following equation (5).

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[0019] In FIG. 5, the line length L from the end of the top plate portion of the first plate L to the contact position between the first plate L and the die T2 is P is the line length L per unit length in the horizontal direction from z=0 to z=L0 i Since it is the sum of the above, it can be expressed by the following equation (6).

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[0020] When attention is paid to the first plate L in this embodiment, the vertical component of the line length of the region of the first plate L that is not clamped in FIG. 5 is the height L of the main body part. H is equal to. Therefore, the linear length of the area of ​​the first plate L that is not clamped, that is, the total linear length of the curved portion excluding the top plate portion and its extension, is defined as L MWhen the inclination angle of the first plate material L at the contact position between the first plate material L and the die mold T2 is θ, the following equation (7) holds true.

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[0021] C1 is derived by recursively calculating a value that satisfies the formulas (3) to (8). Furthermore, by using C1, the deflection deformation of the first plate material L and the second plate material P in this embodiment is derived. In this embodiment, the minimum line length of the region of the second plate P that is not pressed during forming in order to prevent dissociation is the line length L P Therefore, it can be derived using equation (6) when C1 is used.

[0022] Using this derivation method, the dimensions of the first plate material L and the second plate material P in the first form were variously changed, and the relationship between the ratio X of the line length P1 corresponding to the vertical wall portion of the second plate material P to the line length L1 corresponding to the vertical wall portion of the first plate material L, and the angle Y of the vertical wall portion relative to the top plate portion of the overlapping member was calculated.

[0023] 1 shows a schematic diagram of a cross section perpendicular to the bending ridge of a laminated member according to the first embodiment. In this embodiment, line length L1 is the length of a line connecting the intersection of an extended straight line between the top plate portion and vertical wall portion of the first plate L and the intersection of an extended straight line between the vertical wall portion and flange portion of the first plate L. Line length P1 is the length of a line from the end of the top plate portion of the second plate P to the end of the second plate P.

[0024] Table 1 shows the line length L excluding the top plate of the main body part for shapes A and B, which were considered as examples in the first form. M The table shows the dimensions (mm), the vertical wall length of the main body part (mm), the vertical wall length of the reinforcing part (mm), the ratio X of the vertical wall length, and the angle Y of the vertical wall. [Table 1]

[0025] Based on the results of X and Y shown in Table 1 derived from this embodiment, the conditional expression (1) was derived.

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[0026] <Second Form> 8 shows a cross-sectional view of the second embodiment at the moment when the inclination angle of the first plate material L, which constitutes the main body component, at the contact point between the die T2 and the die T2 coincides with the inclination angle of the vertical wall of the die T2. At this time, the first plate material L, which is the metal plate material constituting the main body component, and the second plate material P, which is the metal plate material constituting the reinforcing component, are sandwiched between the punch T1 and the pad T3 in a region corresponding to the top plate. The inclination angle θ of the first plate material L relative to the top plate surface at the point where the first plate material L and the die T2 contact is equal to the rising angle Y of the vertical wall of the overlapping member relative to the top plate.

[0027] The height of the main body part is L H and the rising angle of the vertical wall portion relative to the top plate portion of the overlapping member is Y, L0 in FIG. 8 can be expressed by the following formula (3).

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[0028] When the position where the shoulder of the die mold T2 and the first plate material L first come into contact is defined as the origin O, and the horizontal distance from the origin O toward the center of the main body part is defined as z, the vertical deflection f(z) of the first plate material L and the second plate material P at the distance z can be expressed by the following equation (9) using the distance L0 and C2.

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[0029] where C2 is a coefficient that reflects the magnitude of the deflection deformation of the first plate L and the second plate P. In this embodiment, the inclination angle θ of the first plate L relative to the top surface at the point where the die mold T2 and the first plate L come into contact is a value that determines the deflection deformation at the moment when the rising angle of the vertical wall portion relative to the top plate portion of the overlapping member becomes equal to Y. The process of deriving C2 will be explained below.

[0030] In this embodiment, the following equality (10) holds true.

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[0031] C2 is calculated recursively as a value that satisfies the formulas (3), (8), (9), and (10). Furthermore, by using C2, the deflection deformation of the first plate material L and the second plate material P in this embodiment is derived. In this embodiment, the minimum line length of the region of the second plate P that is not pressed during forming in order to prevent dissociation is the line length L P Therefore, it can be derived using equation (6) when C2 is used.

[0032] Using this derivation method, the dimensions of the first plate material L and the second plate material P in the second form were variously changed, and the relationship between the ratio X of the line length P2 corresponding to the vertical wall portion of the second plate material P to the line length L2 corresponding to the vertical wall portion of the first plate material L, and the angle Y of the vertical wall portion relative to the top plate portion of the overlapping member was calculated.

[0033] 3 shows a schematic diagram of a cross section perpendicular to the bending ridge of the overlapping member according to the second embodiment. In this embodiment, the line length L2 is the line length connecting the intersection point of the extended straight line between the top plate portion and the vertical wall portion of the first plate L and the end of the first plate L, and the line length P2 is the line length from the end of the top plate portion of the second plate P to the end of the second plate P.

[0034] Table 2 shows the vertical wall length (mm) of the main body part, the vertical wall length (mm) of the reinforcing part, the ratio X of the vertical wall length, and the angle Y of the vertical wall for shapes C and D, which were considered as examples in the second form. [Table 2]

[0035] Based on the results of X and Y shown in Table 2 derived from this embodiment, the conditional formula (2) was developed.

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[0036] The method for forming a superposed member of the present invention corresponding to the first embodiment described above includes the steps of: forming a superposed member in which a main body part has a hat-shaped cross section, the main body part having a top plate portion, a vertical wall portion, and a flange portion connected to each other by a bending ridge portion, and a reinforcing part having a U-shaped or L-shaped cross section, the top plate portion and the vertical wall portion connected to each other by a bending ridge portion, are superposed on the inside of the main body part; and forming the superposed member integrally from a joined blank in which a first plate material, which is a metal plate material constituting the main body part, and a second plate material, which is a metal plate material constituting the reinforcing part, are superposed and joined by press forming while clamping and pressing regions of the joined blank corresponding to the top plate portions of the main body part and the reinforcing part; In a cross section perpendicular to the bending ridge of the overlapping member, the linear length of the region of the second plate material corresponding to the bending ridge and the vertical wall of the reinforcing part is made equal to or greater than the linear length from the end of the region of the first plate material corresponding to the top plate portion of the main body part to the contact position with the shoulder of the die mold when the die surface extending from the flange forming surface of the punch mold comes into contact with the plate end of the first plate material during press molding of the joined blank using a pair of punch molds and die molds.

[0037] In addition, the method for molding an overlapping member of the present invention corresponding to the first embodiment described above is a problem-solving means in which, in a cross section perpendicular to the bending ridge of the overlapping member, when the ratio of the line length of the second plate material corresponding to the vertical wall portion of the reinforcing part to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body part is X, the rise angle Y (degrees) of the vertical wall portion relative to the top plate part of the overlapping member satisfies the following formula (1):

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[0038] Furthermore, the overlapping member of the present invention corresponding to the first embodiment is an overlapping member in which a reinforcing part having a U-shaped or L-shaped cross section, which also has a top plate portion and a vertical wall portion connected to each other at a bending ridge portion, is overlapped on the inside of a main body part having a hat-shaped cross section, which has a top plate portion, a vertical wall portion, and a flange portion connected to each other at a bending ridge portion, and the overlapping member is an overlapping member obtained by overlapping and joining a first plate material which is a metal plate material constituting the main body part and a second plate material which is a metal plate material constituting the reinforcing part, and is integrally formed by press-forming a joined blank in a state in which regions of the joined blank corresponding to the top plate portions of the main body part and the reinforcing part are clamped and pressed, In a cross section perpendicular to the bending ridge of the overlapping member, the linear length of the region of the second plate material corresponding to the bending ridge and the vertical wall of the reinforcing part is equal to or greater than the linear length from the end of the region of the first plate material corresponding to the top plate portion of the main body part to the contact position with the shoulder of the die mold when the die surface extending from the flange forming surface of the punch mold comes into contact with the plate end of the first plate material during press forming from the joined blank using a punch mold and a die mold.

[0039] In addition, in the overlapping member of the present invention corresponding to the first embodiment, when the ratio of the line length of the region of the second plate material corresponding to the vertical wall portion of the reinforcing component to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body component in a cross section perpendicular to the bending ridge portion of the overlapping member is defined as X, the rise angle Y of the vertical wall portion relative to the top plate portion of the overlapping member becomes a preferable means for solving the problem, which satisfies the above formula (1).

[0040] On the other hand, the method for forming a superposed member of the present invention corresponding to the second embodiment includes a method for forming a superposed member in which a reinforcing part having a U-shaped or L-shaped cross section, the reinforcing part having a top plate portion and a vertical wall portion connected to each other at a bending ridge portion, is superposed on the inside of a main part having a U-shaped cross section, the top plate portion and the vertical wall portion being connected to each other at a bending ridge portion, and the superposed member is integrally formed by press-forming a joined blank obtained by overlapping and joining a first plate material that is a metal plate material constituting the main part and a second plate material that is a metal plate material constituting the reinforcing part, while clamping and pressing regions of the joined blank that correspond to the top plate portions of the main part and the reinforcing part, In a cross section perpendicular to the bending ridge of the overlapping member, the linear length of the region of the second plate material corresponding to the bending ridge and the vertical wall of the reinforcing part is made equal to or greater than the linear length from the end of the region of the first plate material corresponding to the top plate of the main body part to the contact position with the shoulder of the die mold when the inclination angle of the first plate material at the position where the shoulder of the die mold contacts the first plate material matches the inclination angle of the vertical wall of the die mold during press molding of the joined blank using a pair of punch molds and die molds.

[0041] In addition, the method for molding an overlapping member of the present invention corresponding to the second embodiment described above is a problem-solving means in which, in a cross section perpendicular to the bending ridge of the overlapping member, when the ratio of the line length of the region of the second plate material corresponding to the vertical wall portion of the reinforcing component to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body component is X, the rise angle Y (degrees) of the vertical wall portion relative to the top plate portion of the overlapping member satisfies the following formula (2).

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[0042] Furthermore, the overlapping member of the present invention corresponding to the second embodiment is an overlapping member in which a reinforcing part having a U-shaped or L-shaped cross section, also having a top plate portion and a vertical wall portion connected to each other at a bending ridge portion, is overlapped on the inside of a main part having a U-shaped cross section, the top plate portion and the vertical wall portion connected to each other at a bending ridge portion, and the overlapping member is integrally formed by press-forming a joined blank in which a first plate material that is a metal plate material constituting the main part and a second plate material that is a metal plate material constituting the reinforcing part are overlapped and joined, with regions of the joined blank corresponding to the top plate portions of the main part and the reinforcing part being clamped, In a cross section perpendicular to the bending ridge of the overlapping member, the linear length of the region of the second plate material corresponding to the bending ridge and the vertical wall of the reinforcing part is greater than or equal to the linear length from the end of the region of the first plate material corresponding to the top plate portion of the main body part to the contact position with the shoulder of the die mold when the inclination angle of the first plate material at the position where the shoulder of the die mold contacts the first plate material matches the inclination angle of the vertical wall of the die mold during press molding of the joined blank using a pair of punch molds and die molds.

[0043] In addition, in the overlapping member of the present invention corresponding to the second form described above, when the ratio of the line length of the region of the second plate material corresponding to the vertical wall portion of the reinforcing component to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body component in a cross section perpendicular to the bending ridge portion of the overlapping member is defined as X, the rise angle Y (degrees) of the vertical wall portion relative to the top plate portion of the overlapping member becomes a preferable means for solving the problem, which satisfies the above formula (2).

[0044] Furthermore, a method for manufacturing an automobile part including a superposed member of any of the above embodiments is characterized by including a step of molding the superposed member based on the method for molding a superposed member of any of the above embodiments. [Effects of the Invention]

[0045] The overlapping member forming method of the present invention and the overlapping member press-formed by the forming method of the present invention provide the following advantages. A joined blank is formed by overlapping and joining a first metal plate constituting a main body component with a second metal plate constituting a reinforcing component. The area of ​​the joined blank corresponding to the top plate of the main body component and the reinforcing component is clamped between a pad die and a punch die. When the joined blank is integrally formed by press-forming the overlapping member, separation between the first and second plate members is prevented in the area not clamped between the pad die and the punch die during forming. This prevents gaps from forming between the main body component and the reinforcing component after demolding, thereby avoiding performance degradation of the overlapping member and assembly problems. Automotive components including such overlapping members can be used in automotive frame components, contributing to increased strength and performance of the frame components and achieving excellent collision safety. [Brief explanation of the drawings]

[0046] [Figure 1] 3 is a schematic diagram of a cross section perpendicular to a bending ridge of a superposed member according to the first embodiment. FIG. [Figure 2] 10 is a graph showing the relationship between the ratio X of the line length of the vertical wall portion of the reinforcing component to the line length of the vertical wall portion of the main body component, which is satisfied by the first embodiment of the present invention, and the rising angle Y of the vertical wall portion with respect to the top plate portion of the member. [Figure 3] 10 is a schematic diagram of a cross section perpendicular to a bending ridge of a superposed member according to a second embodiment. FIG. [Figure 4] 10 is a graph showing the relationship between the ratio X of the line length of the vertical wall portion of the reinforcing component to the line length of the vertical wall portion of the main body component, which is satisfied by embodiment 2 of the present invention, and the rising angle Y of the vertical wall portion with respect to the top plate portion of the member. [Figure 5] 1 is a schematic cross-sectional view of the moment when a die surface extending from a flange forming surface of a punch die in the first embodiment comes into contact with an end of a first plate material constituting a main body part. FIG. [Figure 6]10 is a cross-sectional schematic diagram of the wire length of the plate material per unit length in the horizontal direction at point z=i when the first and second plate materials are in a bent state. FIG. [Figure 7] 10 is a graph showing a plot of the ratio X of the vertical wall length and the angle Y of the vertical wall portion in the case considered in the first embodiment, and showing conditional formula (1). [Figure 8] 10 is a cross-sectional view showing the moment when the inclination angle of the first plate material constituting the main body part at the position where the die and the first plate material contact each other coincides with the inclination angle of the vertical wall portion of the die in the second embodiment. FIG. [Figure 9] 10 is a graph showing a plot of the ratio X of the vertical wall length and the angle Y of the vertical wall portion in the case considered in the second embodiment, and showing conditional expression (2). [Figure 10] (a) is an oblique view showing an example of a superposed member according to embodiment 1 of the present invention, (b) is a cross-sectional view showing a schematic half of the superposed member, and (c) is an oblique view showing a reinforcing member in the superposed member. [Figure 11] 10 is a graph showing plots of the ratio X of the vertical wall length and the angle Y of the vertical wall for Test Nos. 1 to 4 according to the first embodiment. [Figure 12] 1A to 1C are cross-sectional views of Test Nos. 1 to 4 according to the first embodiment during molding and after demolding. [Figure 13] (a) is an oblique view showing an example of a superposed member according to embodiment 2 of the present invention, (b) is a cross-sectional view showing a schematic half of the superposed member, and (c) is an oblique view showing a reinforcing member in the superposed member. [Figure 14] 10 is a graph showing plots of the ratio X of the vertical wall length and the angle Y of the vertical wall for Test Nos. 5 to 8 according to the first embodiment. [Figure 15] 10A and 10B are cross-sectional views of test Nos. 5 to 8 according to embodiment 1 during molding and after demolding. DETAILED DESCRIPTION OF THE INVENTION

[0047] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. <Embodiment 1> 1 shows a schematic diagram of a cross section perpendicular to the bending ridge of a laminated member according to a first embodiment. The laminated member here is composed of a first plate L, which is a metal plate constituting a main body component with a hat-shaped cross section, and a second plate P, which is a metal plate constituting a reinforcing component with a U-shaped or L-shaped cross section. In the cross section perpendicular to the bending ridge, the vertical wall portion is bent at an angle Y (degrees) relative to the top plate portion, and the line length corresponding to the vertical wall portion of the first plate L is L1, and the line length corresponding to the vertical wall portion of the second plate P is P1.

[0048] Figure 2 shows the relationship between the ratio X of the line length P1 of the vertical wall portion of the reinforcing component to the line length L1 of the vertical wall portion of the main body component, and the angle Y of the vertical wall portion relative to the top plate portion of the overlapping member, which is satisfied by this embodiment 1 related to the first mode. X is the ratio calculated by dividing the line length P1 corresponding to the vertical wall portion of the second plate material P constituting the reinforcing component in Figure 1 by the line length L1 corresponding to the vertical wall portion of the first plate material L constituting the main body component. Y is the rising angle of the vertical wall portion relative to the top plate portion in Figure 1.

[0049] The preferred range of the rise angle Y that can prevent the first plate material L and the second plate material P from separating during molding changes with the change in the ratio X of the line length of the vertical wall portion of the reinforcing part to the line length of the vertical wall portion of the main body part. The relational expression between the two that shows the preferred range satisfies the following formula (1).

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[0050] According to the first embodiment, for example, when the ratio X of the line length P1 of the vertical wall portion of the reinforcing component to the line length L1 of the vertical wall portion of the main body component is 0.6, the rising angle Y of the vertical wall portion needs to be 60 degrees or more. In this case, separation of the first plate material L and the second plate material P during molding is suppressed. Therefore, no gap is generated between the main body component and the reinforcing component after demolding.

[0051] Fig. 10(a) is a perspective view showing an example of a superposed member according to the first embodiment. Fig. 10(b) is a cross-sectional view showing a schematic half of the superposed member. Fig. 10(c) is a perspective view showing a reinforcing member in the superposed member. This superposed member has a shape in which a constant cross section perpendicular to the bending ridge is extruded 120 mm in a direction along the bending ridge, with the top plate and flange portions being horizontal and the vertical wall portion rising at an angle of 60 degrees from the top plate.

[0052] The dimensions of the first plate material L constituting the main body component in the above cross section were: the length of the top plate portion was 90 mm, the distance between the R ends of the vertical wall portions was 62 mm, and the length of the flange portions was 20 mm. The outer radius of the bent ridge portion connecting the top plate portion and the vertical wall portions was 8.0 mm, and the inner radius of the bent ridge portion connecting the vertical wall portions and the flange portions was 6.0 mm. The dimensions of the second plate material P constituting the reinforcing component in the above cross section were: the length of the top plate portion was 90 mm, and the distance from the R end of the vertical wall portions to the plate material end was 22-50 mm. The inner radius of the bent ridge portion connecting the top plate portion and the vertical wall portions was 5.0 mm.

[0053] In this embodiment, the line length L1 of the first plate L corresponding to the vertical wall portion of the main body part was defined as the line length connecting point U and point S, where U is the intersection point of the extended straight lines of the top plate portion and the vertical wall portion, and S is the intersection point of the extended straight lines of the vertical wall portion and the flange portion. Furthermore, the line length P1 of the second plate P corresponding to the vertical wall portion of the reinforcing part was defined as the line length from the boundary point E between the top plate portion and the bending ridge portion to the end point F of the plate.

[0054] The first plate material L constituting the main body component was made of hot-dip galvanized steel sheet with a tensile strength of 980 MPa and a thickness of 1.4 mm, and the second plate material P constituting the reinforcing component was made of cold-rolled steel sheet with a tensile strength of 1470 MPa and a thickness of 1.6 mm.

[0055] Table 3 shows a list of Test Nos. 1 to 4 according to the first embodiment. [Table 3]

[0056] Fig. 11 shows a plot of the ratio X of the vertical wall length and the angle Y of the vertical wall for Test Nos. 1 to 4 according to embodiment 1. Fig. 12 shows cross-sectional views of Test Nos. 1 to 4 according to embodiment 1 during molding and after demolding.

[0057] In Test No. 1, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 28 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.40. In this case, the angle Y of the vertical wall portion derived from conditional formula (1) is Y ≥ 72.2 degrees. However, in Test No. 1, the angle Y of the vertical wall portion was set to 60 degrees, which did not satisfy conditional formula (1), and separation occurred during molding.

[0058] In Test No. 2, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 35 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.50. In this case, the angle Y of the vertical wall portion derived from conditional formula (1) is Y ≥ 66.5 degrees. However, in Test No. 2, the angle Y of the vertical wall portion was set to 60 degrees, which did not satisfy conditional formula (1), and separation occurred during molding.

[0059] In Test No. 3, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 42 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.60. In this case, the angle Y of the vertical wall portion derived from conditional formula (1) was Y ≥ 59.8 degrees. In Test No. 3, the angle Y of the vertical wall portion was set to 60 degrees, which satisfied conditional formula (1) and did not cause separation during molding.

[0060] In Test No. 4, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 56 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.80. In this case, the angle Y of the vertical wall portion derived from conditional formula (1) was Y ≥ 43.4 degrees. In Test No. 4, the angle of the vertical wall portion was set to 60 degrees, which satisfied conditional formula (1) and did not cause separation during molding.

[0061] <Embodiment 2> 3 shows a schematic diagram of a cross section perpendicular to the bending ridge of a second embodiment of the overlapping member. The overlapping member here is composed of a first plate L, which is a metal plate constituting a main body component with a U-shaped cross section, and a second plate P, which is a metal plate constituting a reinforcing component with a U-shaped or L-shaped cross section. In the cross section perpendicular to the bending ridge, the vertical wall portion is bent at an angle Y (degrees) relative to the top plate portion. The line length corresponding to the vertical wall portion of the first plate L is L2, and the line length corresponding to the vertical wall portion of the second metal plate is P2.

[0062] Figure 4 shows the relationship between the ratio X of the line length P2 of the vertical wall portion of the reinforcing component to the line length L2 of the vertical wall portion of the main body component, and the angle Y of the vertical wall portion relative to the top plate portion of the overlapping member, which is satisfied by this second embodiment related to the second configuration. X is the ratio calculated by dividing the line length P2 corresponding to the vertical wall portion of the second plate material P constituting the reinforcing component in Figure 3 by the line length L2 corresponding to the vertical wall portion of the first plate material L constituting the main body component. Y is the rise angle of the vertical wall portion relative to the top plate portion in Figure 3.

[0063] The preferred range of the rise angle Y that can prevent the first plate material L and the second plate material P from separating during molding changes with the change in the ratio X of the line length of the vertical wall portion of the reinforcing part to the line length of the vertical wall portion of the main body part, and the relationship between the two that indicates the preferred range satisfies the following formula (2).

number

[0064] According to the second embodiment, for example, when the ratio X of the line length of the vertical wall portion of the reinforcing component to the line length of the vertical wall portion of the main body component is 0.8, the rising angle of the vertical wall portion needs to be 54 degrees or more. In this case, separation of the first plate material L and the second plate material P during molding is suppressed. Therefore, no gap is generated between the main body component and the reinforcing component after demolding.

[0065] Fig. 13(a) is a perspective view showing an example of a superposed member according to the second embodiment. Fig. 13(b) is a cross-sectional view showing a schematic half of the superposed member. Fig. 13(c) is a perspective view showing a reinforcing member in the superposed member. This superposed member has a shape in which a constant cross section perpendicular to the bending ridge is extruded 120 mm in a direction along the bending ridge, with the top plate being horizontal and the vertical wall portion rising at an angle of 60 degrees from the top plate.

[0066] The dimensions of the first plate material L constituting the main body component in the above cross section were a top plate length of 90 mm, a distance between the R ends of the vertical wall portions of 65 mm, and an outer bending radius of the bending ridge portion connecting the top plate portion and the vertical wall portions of 8.0 mm. The dimensions of the second plate material P constituting the reinforcing component in the above cross section were a top plate length of 90 mm, and a distance from the R end of the vertical wall portions to the plate end of 22-57 mm. The inner bending radius of the bending ridge portion connecting the top plate portion and the vertical wall portions of 5.0 mm.

[0067] In this embodiment, the line length L2 of the first plate L corresponding to the vertical wall portion of the main body part is the line length connecting point U and the plate end point of the first plate L, when the intersection point of the extended straight line portions of the top plate portion and the vertical wall portion is defined as U. Furthermore, the line length P2 of the second plate P corresponding to the vertical wall portion of the reinforcing part is the line length from the boundary point E between the top plate portion and the bending ridge portion to the end point F of the plate.

[0068] The first plate material L constituting the main body component was made of hot-dip galvanized steel sheet with a tensile strength of 980 MPa and a thickness of 1.4 mm, and the second plate material P constituting the reinforcing component was made of cold-rolled steel sheet with a tensile strength of 1470 MPa and a thickness of 1.6 mm.

[0069] Table 4 shows a list of test Nos. 5 to 8 according to the second embodiment. [Table 4]

[0070] Fig. 14 shows a plot of the ratio X of the vertical wall length and the angle Y of the vertical wall for Test Nos. 5 to 8 according to embodiment 2. Fig. 15 shows cross-sectional views of Test Nos. 5 to 8 according to embodiment 2 during molding and after demolding.

[0071] In Test No. 5, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 28 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.40. In this case, the angle Y of the vertical wall portion derived from conditional formula (2) is Y ≥ 132 degrees. However, in Test No. 5, the angle Y of the vertical wall portion was set to 60 degrees, which did not satisfy conditional formula (2), and separation occurred during molding.

[0072] In Test No. 6, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 42 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.60. In this case, the angle Y of the vertical wall portion derived from conditional formula (2) is Y ≥ 93 degrees. However, in Test No. 6, the angle Y of the vertical wall portion was set to 60 degrees, which did not satisfy conditional formula (2), and separation occurred during molding.

[0073] In Test No. 7, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 56 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.80. In this case, the angle Y of the vertical wall portion derived from conditional formula (2) was Y ≥ 54 degrees. In Test No. 7, the angle of the vertical wall portion was set to 60 degrees, which satisfied conditional formula (2) and did not cause separation during molding.

[0074] In Test No. 8, the length of the first plate L corresponding to the vertical wall portion of the main body part was 70 mm, and the line length of the second plate P corresponding to the vertical wall portion of the reinforcing part was 63 mm. As a result, the ratio X of the vertical wall length of the second plate P to the first plate L was X = 0.90. In this case, the angle Y of the vertical wall portion derived from conditional formula (2) was Y ≥ 35 degrees. In Test No. 8, the angle Y of the vertical wall portion was set to 60 degrees, which satisfied conditional formula (2) and did not cause separation during molding.

[0075] Although the embodiments of the present invention have been described above, the overlapping member molding method of the present invention and the overlapping member of the present invention press-molded by the molding method are not limited to the above-described embodiments. The present invention can be modified as appropriate within the scope of the claims. For example, the overlapping member of the present invention is not limited to automobile bodies, but may also be used for motorcycles, railway vehicle bodies, etc. [Industrial Applicability]

[0076] Thus, according to the overlapping member forming method of the present invention and the overlapping member press-formed by the forming method of the present invention, the areas of the joined blank corresponding to the top plate portions of the main body component and the reinforcing component are clamped with a pad die and a punch die. The joined blank is then integrally press-formed into an overlapping member. During this process, separation of the first and second plate materials does not occur in the areas not clamped by the pad die and the punch die during forming. This prevents gaps from forming between the main body component and the reinforcing component after demolding, avoiding performance degradation of the overlapping member and assembly problems. [Explanation of symbols]

[0077] E (of the first plate L) Boundary point between the top plate and the bending ridge F (End point of first plank L) L First Plank L1 (corresponding to the vertical wall portion of the first plate material L in the first embodiment) Line length L2 (corresponding to the vertical wall portion of the first plate material L in the second embodiment) Line length L O(Line length from the edge of the top plate of the first plate L to the position where the shoulder of the die T2 and the first plate L first come into contact) L H Height (of the main body part) L I Line length (of board per horizontal unit length) L M Line length (of the area of ​​the first plate L that is not clamped) (i.e., the total line length of the curved portion excluding the top plate portion and its extension) L P Line length (from the end of the top plate of the first plate L to the contact position between the first plate L and the die T2) O (the position where the shoulder of the die T2 and the first plate L first come into contact) (origin) P Second board P1 (corresponding to the vertical wall portion of the second plate material P in the first embodiment) Line length P2 (corresponding to the vertical wall portion of the second plate material P in the second embodiment) Line length S (the intersection of the vertical wall and the straight line of the flange of the first plate L) T1 punch type T2 die type T3 Pad type U (Intersection of the top plate and vertical wall of the first plate L) X (ratio of the line length corresponding to the vertical wall portion of the second plate material P to the line length corresponding to the vertical wall portion of the first plate material L) Y (the angle of the vertical wall relative to the top plate of the overlapping member) z Horizontal distance (starting from origin O toward the center of the part) θ (inclination angle of the first plate L at the contact position between the first plate L and the die T2) f(z) deflection (of the first plate L and the second plate P in the vertical direction at a distance z)

Claims

1. a first metal plate that is a metal plate constituting the main body part and a second metal plate that is a metal plate constituting the reinforcing part, and a first metal plate that is a metal plate constituting the main body part are overlapped and joined together to form a superimposed member, the superimposed member being formed by overlapping a U-shaped or L-shaped cross-sectional reinforcing part, the top plate and vertical wall parts being connected to each other at a bending ridge line, inside a main body part having a hat-shaped cross section, the top plate and vertical wall parts being connected to each other at a bending ridge line, and the superimposed member being formed by press-forming a joining blank, the joining blank being formed by overlapping and joining a first metal plate that is a metal plate constituting the main body part and a second metal plate that is a metal plate constituting the reinforcing part, with regions of the joining blank that correspond to the top plate parts of the main body part and the reinforcing part being clamped; In a cross section perpendicular to the bending ridge of the overlapping member, A molding method for a superposed member, characterized in that, when the ratio of the line length of the region of the second plate material corresponding to the vertical wall portion of the reinforcing component to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body component is X, the rise angle Y (degrees) of the vertical wall portion relative to the top plate portion of the superposed member satisfies the following relational expression 1. [Relationship 1] Y≧-50X 2 -12X+85 However, Y is greater than 0 degrees and equal to or less than 90 degrees, and X is equal to or less than 0.

95.

2. A superposed member is formed by superposing a reinforcing part having a U-shaped or L-shaped cross section, the reinforcing part having a top plate portion and a vertical wall portion connected to each other at a bending ridge portion, on the inside of a main body part having a U-shaped cross section, the top plate portion and the vertical wall portion connected to each other at a bending ridge portion, and is integrally formed by press-molding a joined blank obtained by superposing and joining a first plate material that is a metal plate material constituting the main body part and a second plate material that is a metal plate material constituting the reinforcing part, while clamping and pressing regions of the joined blank that correspond to the top plate portions of the main body part and the reinforcing part, In a cross section perpendicular to the bending ridge of the overlapping member, A molding method for a superposed member, characterized in that, when the ratio of the line length of the region of the second plate material corresponding to the vertical wall portion of the reinforcing component to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body component is X, the rise angle Y (degrees) of the vertical wall portion relative to the top plate portion of the superposed member satisfies the following relational expression 2. [Relationship 2] Y≧-195X+210 However, Y is greater than 0 degrees and equal to or less than 90 degrees, and X is equal to or less than 0.

94.

3. a first metal plate that is a metal plate constituting the main body part and a second metal plate that is a metal plate constituting the reinforcing part, and a first metal plate that is a metal plate constituting the main body part are overlapped and joined together to form a superimposed member, the superimposed member being formed by overlapping a U-shaped or L-shaped cross-sectional reinforcing part, the top plate and vertical wall parts being connected to each other at a bending ridge line, inside a main body part having a hat-shaped cross section, the top plate and vertical wall parts being connected to each other at a bending ridge line, and the superimposed member being formed by press-forming a joining blank, the joining blank being formed by overlapping and joining a first metal plate that is a metal plate constituting the main body part and a second metal plate that is a metal plate constituting the reinforcing part, with regions of the joining blank that correspond to the top plate parts of the main body part and the reinforcing part being clamped; In a cross section perpendicular to the bending ridge of the overlapping member, An overlapping member characterized in that, when the ratio of the line length of the region of the second plate material corresponding to the vertical wall portion of the reinforcing part to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body part is X, the rise angle Y (degrees) of the vertical wall portion relative to the top plate portion of the overlapping member satisfies the following relational expression 1. [Relationship 1] Y≧-50X 2 -12X+85 However, Y is greater than 0 degrees and equal to or less than 90 degrees, and X is equal to or less than 0.

95.

4. A superposed member is formed by superposing a reinforcing part having a U-shaped or L-shaped cross section, the reinforcing part having a top plate portion and a vertical wall portion connected to each other at a bending ridge portion, on the inside of a main body part having a U-shaped cross section, the top plate portion and the vertical wall portion connected to each other at a bending ridge portion, and is integrally formed by press-molding a joined blank obtained by superposing and joining a first plate material that is a metal plate material constituting the main body part and a second plate material that is a metal plate material constituting the reinforcing part, while clamping and pressing regions of the joined blank that correspond to the top plate portions of the main body part and the reinforcing part, In a cross section perpendicular to the bending ridge of the overlapping member, An overlapping member characterized in that, when the ratio of the line length of the region of the second plate material corresponding to the vertical wall portion of the reinforcing component to the line length of the region of the first plate material corresponding to the vertical wall portion of the main body component is X, the rise angle Y (degrees) of the vertical wall portion relative to the top plate portion of the overlapping member satisfies the following relational expression 2. [Relationship 2] Y≧-195X+210 However, Y is greater than 0 degrees and equal to or less than 90 degrees, and X is equal to or less than 0.94.

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