Method for forming an overlapping member, overlapping member stamped and formed by the method, and method for manufacturing an automobile part

Abstract

Prevent separation of the sheet of the joint blank in the area not pinched by the press die and the punch die when a superposed member is press-formed from the joint blank. In a superposed member formed by press-forming a joint blank in which a metal sheet constituting a reinforcing member, i.e., a second sheet, is superposed and joined with a metal sheet constituting a main body member, i.e., a first sheet, by press-forming, the line length of the area of the second sheet corresponding to the bending portion and the vertical wall portion in the cross section orthogonal to the bending ridge is set to be more than the line length from the end portion of the area corresponding to the top plate portion of the first sheet to the contact position with the shoulder portion of the die of the punch die when the flange forming surface of the punch die is extended to obtain the die surface in the press-forming of the superposed member using a pair of punch dies and die dies.

Description

Technical Field

[0001] This invention relates to a method for forming overlapping members by stamping an overlapping member from a joining blank formed by overlapping and joining metal sheets, and to an overlapping member stamped by the forming method. Furthermore, it relates to a method for manufacturing automotive parts including the overlapping member. Background Technology

[0002] For automotive skeleton components, the requirements are to suppress body deformation during a collision and protect the interior space by absorbing collision energy. In recent years, in order to achieve better collision safety, there has been a push to increase the strength and performance of skeleton components.

[0003] Most of the skeletal components are formed from long strips with cap-shaped or U-shaped cross-sections. As one means of improving the performance of such components, reinforcing members are sometimes overlapped and joined on the outside or inside of the main body components.

[0004] Typically, components with such overlapping structures are manufactured by stamping the main body and reinforcing parts separately from sheet metal, holding them in an overlapping state, and joining them using various methods such as spot welding. Furthermore, a method has been proposed where sheet metal is pre-overlapped before forming the two parts, and the two parts are simultaneously stamped from these overlapping metal sheets to manufacture the components as a single unit.

[0005] For example, Patent Document 1 describes a method for overlapping and forming an overlapping member by overlapping a metal sheet as a main component and a metal sheet as a reinforcing component. In this method, a second sheet with a smaller area and greater thickness than the first sheet is joined to the back side in the extending direction of the first sheet. Then, with the outer edge of the first sheet constrained, the main component is formed by bulging from the first sheet, and the reinforcing component is formed unconstrained from the second sheet.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2002-192245 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] In the method described in Patent Document 1, when forming overlapping members with a cap-shaped or U-shaped cross-section, such as a skeleton component, by stamping, the area of ​​the sheet metal corresponding to the top plate portion bends during the forming of the main component. Therefore, there is a problem that the shape of the overlapping member deviates significantly from its normal dimensions due to springback after demolding.

[0011] As a solution to the aforementioned problems, there exists a stamping forming method in which the area corresponding to the top plate portion of a sheet metal is clamped by a blank holder and a punch, while the main body component is formed by bulging using the same punch and die, thus suppressing bending in the area corresponding to the top plate portion. However, when integrally forming overlapping components with a hat-shaped or U-shaped cross-section using this stamping forming method, the area corresponding to the top plate portion is clamped by the blank holder and the punch. On the other hand, in areas corresponding to the curved ridges and longitudinal walls that are not clamped by the blank holder and the punch, separation sometimes occurs during forming between the first sheet metal constituting the main body component and the second sheet metal constituting the reinforcing component. Furthermore, in this case, a gap is generated between the main body component and the reinforcing component after demolding, resulting in reduced performance of the overlapping component and obstacles to assembly.

[0012] Therefore, the object of the present invention is to provide a forming method for integrally forming an overlapping member consisting of a main body component with a hat-shaped or U-shaped cross-section and a reinforcing component with a U-shaped or L-shaped cross-section by stamping, thereby solving the above-mentioned problems. Furthermore, the object of the present invention is to provide an overlapping member formed by stamping using this forming method. Moreover, the object of the present invention is to provide a method for manufacturing an automotive component including this overlapping member.

[0013] Methods for solving problems

[0014] To solve the aforementioned problem, the inventors conducted the following research. First, a metal sheet constituting a hat-shaped or U-shaped cross-section of the main component was used as the first sheet, and a metal sheet constituting a U-shaped or L-shaped cross-section of the reinforcing component was used as the second sheet. The regions of the first sheet corresponding to the top plate of the main component and the second sheet corresponding to the top plate of the reinforcing component were clamped together using a blank holder and a punch die. Then, an overlapping member of the main component and the reinforcing component was integrally formed from these first and second sheets by stamping based on the punch die and a die. Various changes were made to the line lengths of the first and second sheets during this forming process, and the deflection of each sheet during the forming of the cross-section of the overlapping member orthogonal to the curved edge was calculated. The results were studied in detail, and it was found that there are two types of separation between the two sheets.

[0015] In the first embodiment, the main body component has a cap-shaped cross-section with a top plate portion, a longitudinal wall portion, and a flange portion interconnected by curved ridge portions, and the reinforcing component has a U-shaped or L-shaped cross-section with a top plate portion and a longitudinal wall portion interconnected by curved ridge portions. In the forming of the overlapping member up to the end of the first sheet metal contacting the die surface obtained by extending the flange forming surface of the punch die forming the flange portion, the linear length of the region of the second sheet metal not clamped during forming, i.e., the total linear length corresponding to the curved ridge portion and longitudinal wall portion after forming, is shorter than the linear length of the first sheet metal from the end of the region corresponding to the top plate portion to the contact position where it contacts the shoulder of the punch die.

[0016] In the second embodiment, the main body component has a U-shaped cross-sectional shape with a top plate portion and a longitudinal wall portion interconnected by curved ridge portions, and the reinforcing component has a U-shaped or L-shaped cross-sectional shape with a top plate portion and a longitudinal wall portion interconnected by curved ridge portions. In the forming of an overlapping member where the inclination angle of the first sheet metal at the point where the shoulder of the die contacts the first sheet metal is consistent with the inclination angle of the forming surface of the longitudinal wall portion of the die, the linear length of the region of the second sheet metal not clamped during forming, i.e., the total linear length corresponding to the curved ridge portion and the longitudinal wall portion after forming, is shorter than the linear length of the first sheet metal from the end of the region corresponding to the top plate portion to the contact point where it contacts the shoulder of the die.

[0017] To solve the aforementioned problems, the present invention has the following structure. First, the ratio of the line length of the second plate corresponding to the formed longitudinal wall portion in the cross-section orthogonal to the curved edge portion of the overlapping member to the line length of the first plate corresponding to the formed longitudinal wall portion is set as X. At this time, the condition that the vertical angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion should satisfy is considered. Furthermore, this conditional expression is derived for both the first and second methods. Hereinafter, refer to... Figures 5-11 The method for deriving the conditional expression is explained. It should be noted that even if the vertical angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion is a relatively large angle of inclination of 90 degrees, in this specification, for convenience, the wall portion connected to the top plate portion via the curved ridge portion will also be referred to as the "longitudinal wall portion".

[0018] <First Method>

[0019] Figure 5 This is a cross-sectional view showing the moment when the die surface obtained by extending the forming surface of the flange portion of the punch die T1, in the first embodiment, contacts the end of the first sheet metal L constituting the main body component. At this time, the metal sheet constituting the main body component, i.e., the first sheet metal L, and the metal sheet constituting the reinforcing component, i.e., the second sheet metal P, are clamped by the punch die T1 and the blank holder T3 in the region corresponding to the top plate portion. Moreover, the end of the first sheet metal L contacts the die surface obtained by extending the forming surface of the flange portion of the punch die T1.

[0020] If the height of the main component is set to L H If the vertical angle of the longitudinal wall portion of the overlapping component relative to the top plate portion is set as Y, then... Figure 5 The distance L0 in the middle is represented by the following equation (3).

[0021] [Mathematical Expression 1]

[0022] The origin O is set as the initial contact point between the shoulder of the die T2 and the first sheet L, and the horizontal distance from the origin O to the center of the component is set as z. At this time, the deflection f(z) in the vertical direction at the distance z between the first sheet L and the second sheet P is expressed by the following equation (4) using the distances L0 and C1.

[0023] [Mathematical Expression 2]

[0024] Wherein, C1 is a coefficient reflecting the magnitude of the flexural deformation of the first sheet L and the second sheet P. In this embodiment, it is a value such that it represents the flexural deformation at the instant the die surface, obtained by extending the forming surface of the flange portion of the punch die T1, contacts the end of the first sheet L. The process of deriving C1 will be explained below.

[0025] Figure 6 This is a schematic cross-sectional view showing the line length per unit length of a flexed metal sheet in the horizontal direction. The flexed sheet has a curved shape. On the other hand, each unit length can be approximated as a straight line.

[0026] Therefore, if we use the vertical deflection f(i) of the first and second plates when z=i and the vertical deflection f(i+1) of the first and second plates when z=i+1, then the linear length L of the plate per unit length in the horizontal direction is... i It is represented by the following formula (5).

[0027] [Mathematical Expression 3]

[0028] exist Figure 5 In the diagram, the line length L is from the end of the top plate portion of the first plate L to the contact position where the first plate L contacts the stamping die T2. P L is the length of the line per unit length in the horizontal direction from z=0 to z=L0. i The sum of is therefore represented by the following equation (6).

[0029] [Mathematical Expression 4]

[0030] Focusing on the first board material L in this method, Figure 5 In the middle, the vertical component of the linear length of the uncrushed area of ​​the first plate L is related to the height L of the main component. H equal.

[0031] Therefore, let L be the linear length of the uncrushed area of ​​the first plate L, that is, the total linear length of the curved portion and its extension excluding the top plate portion. M When the inclination angle of the first plate L at the contact position with the stamping die T2 is set as θ, the following equation (7) holds true.

[0032] [Mathematical Expression 5]

[0033] θ is calculated using the following formula (8).

[0034] [Mathematical Expression 6]

[0035] C1 is derived recursively as a value satisfying equations (3) to (8). Furthermore, by using C1, the flexural deformation of the first plate L and the second plate P in this method is derived.

[0036] In this method, the minimum linear length of the area of ​​the second sheet P that is not clamped during forming, required to prevent separation, becomes Figure 5 Line length L P Therefore, we can derive it using equation (6) when using C1.

[0037] Using this derivation method, various changes are made to the dimensions of the first plate L and the second plate P under the first method, and the relationship between the ratio X of the line length P1 of the second plate P corresponding to the line length L1 of the first plate L corresponding to the longitudinal wall portion and the angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion is calculated.

[0038] Figure 1 This is a schematic diagram showing a cross-section orthogonal to the curved edge of the overlapping member in the first embodiment. In this embodiment, line length L1 is defined as the line length connecting the intersection point obtained by extending the straight section of the top plate portion and the longitudinal wall portion of the first plate L, and the intersection point obtained by extending the straight section of the longitudinal wall portion and the flange portion of the first plate L. Additionally, line length P1 is defined as the line length from the end of the top plate portion of the second plate P to the end of the second plate P.

[0039] Table 1 shows the line length L of the main body components of shapes A and B, excluding the top plate portion, in the first embodiment, which are studied as examples. M A list of the following: length of the longitudinal wall of the main component (mm), length of the longitudinal wall of the reinforcing component (mm), ratio of the length of the longitudinal wall X, and angle of the longitudinal wall Y.

[0040] [Table 1]

[0041] Based on the results of X and Y recorded in Table 1 derived from this method, the conditional expression of equation (1) is derived.

[0042] [Mathematical Expression 7]

[0043] Figure 7 The plotting and conditional expression (1) represent the ratio X of the length of the longitudinal wall of the examples A and B studied in the first method to the angle Y of the longitudinal wall.

[0044] <Second Method>

[0045] Figure 8 This is a cross-sectional view showing the instant at which the inclination angle of the first sheet metal L, at the point where the die T2 contacts the first sheet metal L constituting the main body component, is equal to the inclination angle of the longitudinal wall portion of the die T2. At this moment, the metal sheet constituting the main body component, i.e., the first sheet metal L, and the metal sheet constituting the reinforcing member, i.e., the second sheet metal P, are clamped by the punch die T1 and the blank holder die T3 in the region corresponding to the top plate portion. Furthermore, the inclination angle θ of the first sheet metal L relative to the top plate surface at the point where the first sheet metal L contacts the die T2 is equal to the standing angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion.

[0046] If the height of the main component is set to L H If the vertical angle of the longitudinal wall portion of the overlapping component relative to the top plate portion is set as Y, then... Figure 8 L0 in the equation is represented by the following equation (3).

[0047] [Mathematical Expression 8]

[0048] When the position where the shoulder of the stamping die T2 initially contacts the first sheet L is set as the origin O, and the horizontal distance from the origin O to the center of the main body component is set as z, the deflection f(z) at the distance z between the first sheet L and the second sheet P is expressed by the following formula (9) using distances L0 and C2.

[0049] [Mathematical Expression 9]

[0050] Wherein, C2 is a coefficient reflecting the magnitude of the flexural deformation of the first sheet L and the second sheet P. In this embodiment, it is a value such that at the instant when the inclination angle θ of the first sheet L relative to the top plate surface at the point where the die T2 contacts the first sheet L is equal to the upright angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion, the flexural deformation is measured. The process of deriving C2 will be explained below.

[0051] In this method, the following equation (10) holds true.

[0052] [Mathematical Expression 10]

[0053] θ is calculated using the following formula (8).

[0054] [Mathematical Expression 11]

[0055] C2 is recursively calculated as the value satisfying equations (3), (8), (9), and (10). Furthermore, by using C2, the flexural deformation of the first plate L and the second plate P in this method is derived.

[0056] In this method, the minimum linear length of the area of ​​the second sheet P that is not clamped during forming, required to prevent separation, becomes Figure 8 Line length L P Therefore, we can derive it using equation (6) when using C2.

[0057] Using this derivation method, various changes are made to the dimensions of the first plate L and the second plate P in the second method, and the relationship between the ratio X of the line length P2 of the second plate P corresponding to the line length L2 of the first plate L corresponding to the longitudinal wall portion and the angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion is calculated.

[0058] Figure 3 This is a schematic diagram showing a cross-section of the overlapping member in the second embodiment, orthogonal to the curved edge. In this embodiment, line length L2 is defined as the line length connecting the intersection point obtained by extending the straight section of the top plate portion and the longitudinal wall portion of the first plate L to the end of the first plate L, and line length P2 is defined as the line length from the end of the top plate portion of the second plate P to the end of the second plate P.

[0059] Table 2 shows a list of the longitudinal wall length (mm) of the main body component, the longitudinal wall length (mm) of the reinforcing component, the ratio X of the longitudinal wall length, and the angle Y of the longitudinal wall for shapes C and D, which are studied as examples in the second method.

[0060] [Table 2]

[0061] Based on the results of X and Y recorded in Table 2 derived from this method, the conditional expression of equation (2) was developed.

[0062] [Mathematical Expression 12]

[0063] Among them, 0 <Y≤90。

[0064] Figure 9 The plotting and conditional expression (2) represent the ratio X of the longitudinal wall length to the angle Y of the longitudinal wall portion in the case studied in the second method.

[0065] The forming method of the overlapping member of the present invention, corresponding to the first method described above, is characterized in that the overlapping member is formed by overlapping a reinforcing member having a U-shaped or L-shaped cross-section having a top plate portion and a longitudinal wall portion connected by curved ridge portions inside a main body portion having a hat-shaped cross-section having a top plate portion, a longitudinal wall portion and a flange portion connected by curved ridge portions. The area corresponding to the top plate portion of the main body portion and the reinforcing member is clamped from a joining blank formed by overlapping and joining a metal sheet constituting the main body portion (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet). When the overlapping member is integrally formed by stamping, in a cross section orthogonal to the curved ridge portion of the overlapping member, the line length of the region of the second sheet material corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first sheet material from the end of the region corresponding to the top plate portion of the main body member to the contact position where it contacts the shoulder of the die when the die surface obtained by extending the forming surface of the flange portion of the punch die in the stamping of the joining blank using a pair of punch dies and a die is in contact with the end of the first sheet material.

[0066] It should be noted that, in the forming method of the overlapping member of the present invention corresponding to the first method described above, a preferred solution to the problem is that, in the cross section of the overlapping member orthogonal to the curved ridge portion, when the ratio of the line length of the longitudinal wall portion of the second plate corresponding to the reinforcing member to the line length of the region of the longitudinal wall portion of the first plate corresponding to the main body portion is set to X, the standing angle Y (degrees) of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the following formula (1).

[0067] [Mathematical Expression 13]

[0068] Furthermore, the overlapping member of the present invention, corresponding to the first aspect described above, is characterized in that the overlapping member is formed by overlapping a reinforcing member having a U-shaped or L-shaped cross-section having a top plate portion and a longitudinal wall portion interconnected by curved ridge portions inside a main body component having a hat-shaped cross-section having a top plate portion, a longitudinal wall portion, and a flange portion interconnected by curved ridge portions. The area corresponding to the top plate portion of the main body component and the reinforcing member is clamped from a joining blank formed by overlapping and joining a metal sheet constituting the main body component (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet). In a state where an overlapping member is integrally formed by stamping, in a cross-section of the overlapping member orthogonal to the curved ridge portion, the line length of the region of the second sheet material corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first sheet material from the end of the region corresponding to the top plate portion of the main body member to the contact position where it contacts the shoulder of the die when the die surface obtained by extending the forming surface of the flange portion of the punch during the stamping process of the joining blank is in contact with the end of the first sheet material.

[0069] It should be noted that the preferred solution to the problem of the overlapping member of the present invention corresponding to the first method described above is that, in the cross section of the overlapping member orthogonal to the curved ridge portion, when the ratio of the line length of the region of the second plate corresponding to the longitudinal wall portion of the reinforcing member to the line length of the region of the first plate corresponding to the longitudinal wall portion of the main body portion is set to X, the standing angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the following formula (1).

[0070] On the other hand, the forming method of the overlapping member of the present invention corresponding to the second method described above is characterized in that the overlapping member is formed by overlapping a reinforcing member having a U-shaped or L-shaped cross-section having a top plate portion and a longitudinal wall portion connected by curved ridge portions inside a main body member having a U-shaped cross-section having a top plate portion and a longitudinal wall portion connected by curved ridge portions. This is achieved by clamping the area corresponding to the top plate portion of the main body member and the reinforcing member in a bonding blank formed by overlapping and joining a metal sheet constituting the main body member (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet). When the overlapping member is integrally formed by stamping, in a cross-section of the overlapping member orthogonal to the curved ridge portion, the line length of the region of the second sheet material corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first sheet material from the end of the region corresponding to the top plate portion of the main body member to the contact position where it contacts the shoulder of the die in the stamping of the joining blank using a pair of punches and dies.

[0071] It should be noted that, in the forming method of the overlapping member of the present invention corresponding to the second method described above, the preferred method for solving the problem is that, in the cross section of the overlapping member orthogonal to the curved ridge portion, when the ratio of the line length of the region of the second plate corresponding to the longitudinal wall portion of the reinforcing member to the line length of the region of the first plate corresponding to the longitudinal wall portion of the main body portion is set to X, the standing angle Y (degrees) of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the following formula (2).

[0072] [Mathematical Expression 14]

[0073] Among them, 0 <Y≤90。

[0074] Furthermore, the overlapping member of the present invention, corresponding to the second aspect described above, is characterized in that the overlapping member is formed by overlapping a reinforcing member having a U-shaped or L-shaped cross-section having a top plate portion and a longitudinal wall portion interconnected by curved ridge portions inside a main body component having a U-shaped cross-section having a top plate portion and a longitudinal wall portion interconnected by curved ridge portions. This is achieved by stamping a joining blank formed by overlapping and joining a metal sheet constituting the main body component (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet), with the area corresponding to the top plate portion of the main body component and the reinforcing member clamped in the joining blank. In an integrally formed overlapping component, in a cross-section of the overlapping component orthogonal to the curved ridge portion, the line length of the region of the second plate corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first plate from the end of the region corresponding to the top plate portion of the main component to the contact position where it contacts the shoulder of the die in the stamping process of the joining blank using a pair of punches and dies.

[0075] It should be noted that the preferred solution to the problem of the overlapping member of the present invention corresponding to the second method described above is that, in the cross section of the overlapping member orthogonal to the curved ridge portion, when the ratio of the line length of the region of the second plate corresponding to the longitudinal wall portion of the reinforcing member to the line length of the region of the first plate corresponding to the longitudinal wall portion of the main body portion is set to X, the standing angle Y (degrees) of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the above formula (2).

[0076] Furthermore, the method for manufacturing automotive parts including overlapping members of any of the above methods is characterized by a step of forming the overlapping members using a forming method based on the overlapping members of any of the above methods.

[0077] Invention Effects

[0078] The overlapping member forming method of the present invention and the overlapping member formed by stamping using this forming method can achieve the following effects. In a joining blank formed by overlapping and joining a metal sheet constituting a reinforcing member (a second sheet) onto a metal sheet constituting a main component (a first sheet), the area corresponding to the top plate portion of the main component and the reinforcing member is clamped by a blank holder die and a punch die. Furthermore, when the overlapping member is integrally formed from this joining blank by stamping, separation of the first and second sheets does not occur in areas not clamped by the blank holder die and punch die during forming. Therefore, the following effects can be achieved: preventing gaps between the main component and the reinforcing member after demolding, and avoiding performance degradation and assembly obstacles of the overlapping member. Automotive components including such overlapping members, used in automotive frame components, contribute to high strength and high performance of the frame components, enabling excellent crash safety. Attached Figure Description

[0079] Figure 1 This is a schematic diagram of a cross-section of the overlapping member of the first type, orthogonal to the curved edge.

[0080] Figure 2 It is a graph showing the relationship between the ratio X of the length of the longitudinal wall portion of the reinforcing member to the length of the longitudinal wall portion of the main body member, and the standing angle Y of the longitudinal wall portion of the member relative to the top plate portion, as satisfied in Embodiment 1 of the present invention.

[0081] Figure 3 This is a schematic diagram of a cross-section of the overlapping member of the second type, orthogonal to the curved ridge.

[0082] Figure 4 This is a graph showing the relationship between the ratio X of the length of the longitudinal wall portion of the reinforcing member to the length of the longitudinal wall portion of the main body member, as satisfied in Embodiment 2 of the present invention, and the standing angle Y of the longitudinal wall portion of the member relative to the top plate portion.

[0083] Figure 5 It is a cross-sectional schematic diagram of the moment when the mold surface, obtained by extending the flange forming surface of the punch mold of the first method, contacts the end of the first plate that constitutes the main body component.

[0084] Figure 6 It is a cross-sectional diagram showing the line length of the plate per unit length in the horizontal direction at location z=i when the first and second plates are in a bent state.

[0085] Figure 7 It is a plot of the ratio X of the length of the longitudinal wall to the angle Y of the longitudinal wall in the example studied in the first method, and a curve of the condition (1).

[0086] Figure 8This is a cross-sectional schematic diagram showing the moment when the inclination angle of the first plate at the contact point between the stamping die and the first plate constituting the main body component in the second method is consistent with the inclination angle of the longitudinal wall of the stamping die.

[0087] Figure 9 It is a plot of the ratio X of the length of the longitudinal wall to the angle Y of the longitudinal wall in the case studied in the second method, and a curve of the condition (2).

[0088] Figure 10 (a) is a perspective view showing the overlapping member of an embodiment of Embodiment 1 of the present invention. Figure 10 (b) is a cross-sectional view showing a schematic half of the overlapping member. Figure 10 (c) is a perspective view of the reinforcing member of the overlapping member.

[0089] Figure 11 It is a graph showing the ratio X of the length of the longitudinal wall portion to the angle Y of the longitudinal wall portion in experiments No.1 to 4 of Embodiment 1.

[0090] Figure 12 These are cross-sectional views of Experiments No. 1 to 4 of Embodiment 1 during molding and after demolding.

[0091] Figure 13 (a) is a perspective view showing the overlapping member of an embodiment of Embodiment 2 of the present invention. Figure 13 (b) is a cross-sectional view showing a schematic half of the overlapping member. Figure 13 (c) is a perspective view of the reinforcing member of the overlapping member.

[0092] Figure 14 It is a graph showing the ratio X of the length of the longitudinal wall portion to the angle Y of the longitudinal wall portion in tests No.5 to 8 of Embodiment 1.

[0093] Figure 15 These are cross-sectional views of Experiments No. 5 to 8 of Embodiment 1 during molding and after demolding. Detailed Implementation

[0094] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0095] <Implementation Method 1>

[0096] Figure 1This is a schematic diagram showing a cross-section orthogonal to the curved ridge of the overlapping member in the first embodiment. The overlapping member here is composed of a first sheet L, which forms the main body component with a hat-shaped cross-section, and a second sheet P, which forms the reinforcing component with a U-shaped or L-shaped cross-section. In the cross-section orthogonal to the curved ridge, the longitudinal wall portion is curved relative to the top plate portion at an angle Y (degrees). The line length of the first sheet L corresponding to the longitudinal wall portion is L1, and the line length of the second sheet P corresponding to the longitudinal wall portion is P1.

[0097] Figure 2 This indicates the relationship between the ratio X of the line length P1 of the longitudinal wall portion of the reinforcing member to the line length L1 of the longitudinal wall portion of the main body member, and the angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion, as satisfied in Embodiment 1 of the first method. X is the ratio X of the line length P1 of the longitudinal wall portion of the reinforcing member to the line length L1 of the longitudinal wall portion of the main body member, as satisfied in Embodiment 1 of the first method. Figure 1 The ratio Y is calculated by dividing the linear length P1 of the second plate P constituting the reinforcing component, corresponding to the longitudinal wall portion, by the linear length L1 of the first plate L constituting the main component, corresponding to the longitudinal wall portion. Figure 1 The vertical angle of the longitudinal wall relative to the top plate.

[0098] The preferred range of the stand-up angle Y that can suppress the separation of the first sheet L and the second sheet P during forming varies with the ratio X of the linear length of the longitudinal wall of the reinforcing member to the linear length of the longitudinal wall of the main body member. The relationship between the two, which represents the preferred range, satisfies the following equation (1).

[0099] [Mathematical Expression 15]

[0100] According to Embodiment 1, for example, when the ratio X of the line length P1 of the longitudinal wall portion of the reinforcing member to the line length L1 of the longitudinal wall portion of the main body member is 0.6, the vertical angle Y of the longitudinal wall portion needs to be 60 degrees or more. In this case, separation between the first sheet L and the second sheet P during molding is suppressed. Therefore, no gap is generated between the main body member and the reinforcing member after demolding.

[0101] Figure 10 (a) is a perspective view of the overlapping component of the embodiment of the above-described embodiment 1. Figure 10 (b) is a cross-sectional view showing a rough half of the overlapping member. Figure 10 (c) is a perspective view showing the reinforcing member in the overlapping member. The overlapping member is designed to have a certain cross section orthogonal to the curved edge portion protruding 120 mm in the direction along the curved edge portion, with the top plate portion and flange portion being horizontal, and the longitudinal wall portion being set at an angle of 60 degrees from the top plate portion.

[0102] Regarding the dimensions of the first plate L constituting the main component in the above cross-section, the length of the top plate portion is set to 90 mm, the distance between the rounded corner terminations of the longitudinal walls is set to 62 mm, and the length of the flange portion is set to 20 mm. Furthermore, the outer radius of the curved edge portion connecting the top plate portion and the longitudinal walls is set to 8.0 mm, and the inner radius of the curved edge portion connecting the longitudinal walls and the flange portion is set to 6.0 mm. Regarding the dimensions of the second plate P constituting the reinforcing member in the above cross-section, the length of the top plate portion is set to 90 mm, and the distance from the rounded corner termination of the longitudinal walls to the end of the plate is set to 22-50 mm. Furthermore, the inner radius of the curved edge portion connecting the top plate portion and the longitudinal walls is set to 5.0 mm.

[0103] In this embodiment, when the intersection point obtained by extending the straight section of the top plate portion and the longitudinal wall portion is defined as U, and the intersection point obtained by extending the straight section of the longitudinal wall portion and the flange portion is defined as S, the line length L1 of the longitudinal wall portion of the first plate L, which corresponds to the main body component, is the line length connecting point U and point S. Furthermore, the line length P1 of the longitudinal wall portion of the second plate P, which corresponds to the reinforcing member, is defined as the line length from the boundary point E between the top plate portion and the curved ridge portion to the end point F of the plate.

[0104] The first sheet L constituting the main component is made of galvanized steel sheet with a tensile strength of 980 MPa and a thickness of 1.4 mm. The second sheet P constituting the reinforcing component is made of cold-rolled steel sheet with a tensile strength of 1470 MPa and a thickness of 1.6 mm.

[0105] Table 3 shows a list of tests No. 1 to 4 of this embodiment 1.

[0106] [Table 3]

[0107] Figure 11 This plot shows the ratio X of the longitudinal wall length to the angle Y of the longitudinal wall in experiments No. 1 to 4 of Embodiment 1. Additionally, Figure 12 The cross-sectional views show the molding and demolding of Experiments No.1 to No.4 of Embodiment 1.

[0108] In Experiment No. 1, the length of the longitudinal wall portion of the first sheet L, corresponding to the main component, was set to 70 mm, and the length of the longitudinal wall portion of the second sheet P, corresponding to the reinforcing component, was set to 28 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second sheet P to that of the first sheet L was X = 0.40. At this time, the angle Y of the longitudinal wall portion derived from condition (1) was Y ≥ 72.2 degrees. However, in Experiment No. 1, because the angle Y of the longitudinal wall portion was set to 60 degrees, condition (1) was not satisfied, and separation occurred during molding.

[0109] In Experiment No. 2, the length of the longitudinal wall portion of the first plate L, which corresponds to the main component, was set to 70 mm, and the length of the longitudinal wall portion of the second plate P, which corresponds to the reinforcing component, was set to 35 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second plate P relative to that of the first plate L was X = 0.50. At this time, the angle Y of the longitudinal wall portion derived from condition (1) was Y ≥ 66.5 degrees. However, Experiment No. 2, because it set the angle Y of the longitudinal wall portion to 60 degrees, did not satisfy condition (1), and separation occurred during molding.

[0110] In Experiment No. 3, the length of the longitudinal wall portion of the first sheet L, corresponding to the main component, is set to 70 mm, and the length of the longitudinal wall portion of the second sheet P, corresponding to the reinforcing component, is set to 42 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second sheet P relative to that of the first sheet L is X = 0.60. At this time, the angle Y of the longitudinal wall portion derived from condition (1) is Y ≥ 59.8 degrees. Since the angle Y of the longitudinal wall portion in Experiment No. 3 is 60 degrees, condition (1) is satisfied, and separation does not occur during molding.

[0111] In Experiment No. 4, the length of the longitudinal wall portion of the first sheet L, corresponding to the main component, was set to 70 mm, and the length of the longitudinal wall portion of the second sheet P, corresponding to the reinforcing component, was set to 56 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second sheet P to that of the first sheet L was X = 0.80. At this time, the angle Y of the longitudinal wall portion derived from condition (1) was Y ≥ 43.4 degrees. Because Experiment No. 4 set the angle of the longitudinal wall portion to 60 degrees, condition (1) was satisfied, and separation did not occur during molding.

[0112] <Implementation Method 2>

[0113] Figure 3 This is a schematic diagram showing a cross-section orthogonal to the curved ridge of the overlapping member in the second configuration. The overlapping member here consists of a first sheet L, which forms the main body of the U-shaped cross-section, and a second sheet P, which forms the reinforcing member of the U-shaped or L-shaped cross-section. In the cross-section orthogonal to the curved ridge, the longitudinal wall is curved relative to the top plate at an angle Y (degrees). The line length of the first sheet L corresponding to the longitudinal wall is L2, and the line length of the second sheet L corresponding to the longitudinal wall is P2.

[0114] Figure 4 This indicates the relationship between the ratio X of the line length P2 of the longitudinal wall portion of the reinforcing member to the line length L2 of the longitudinal wall portion of the main body member, and the angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion, as satisfied in Embodiment 2 of the second method. X represents the ratio X of the line length P2 of the longitudinal wall portion of the reinforcing member to the line length L2 of the longitudinal wall portion of the main body member, as satisfied in Embodiment 2 of the second method. Figure 3 The ratio Y is calculated by dividing the linear length P2 of the second plate P constituting the reinforcing component, corresponding to the longitudinal wall portion, by the linear length L2 of the first plate L constituting the main component, corresponding to the longitudinal wall portion. Figure 3The vertical angle of the longitudinal wall relative to the top plate.

[0115] The preferred range of the stand-up angle Y that can suppress the separation of the first plate L and the second plate P during forming varies with the ratio X of the length of the longitudinal wall of the reinforcing member to the length of the longitudinal wall of the main body member, and the relationship between the two, which represents the preferred range, satisfies the following equation (2).

[0116] [Mathematical Expression 16]

[0117] Among them, 0 <Y≤90。

[0118] According to Embodiment 2, for example, when the ratio X of the linear length of the longitudinal wall portion of the reinforcing member to the linear length of the longitudinal wall portion of the main body member is 0.8, the vertical angle of the longitudinal wall portion needs to be 54 degrees or more. In this case, separation of the first sheet L and the second sheet P during molding is suppressed. Therefore, no gap is generated between the main body member and the reinforcing member after demolding.

[0119] Figure 13 (a) is a perspective view of the overlapping member of the embodiment of the above-described embodiment 2. Figure 13 (b) is a cross-sectional view showing a rough half of the overlapping member. Figure 13 (c) is a perspective view showing the reinforcing member in the overlapping member. The overlapping member is designed to have a certain cross section orthogonal to the curved edge portion protruding 120 mm in the direction along the curved edge portion, with the top plate portion being horizontal and the longitudinal wall portion being set at an angle of 60 degrees from the top plate portion.

[0120] Regarding the dimensions of the first plate L constituting the main component in the above cross-section, the length of the top plate portion is set to 90 mm, the distance between the rounded corner terminations of the longitudinal walls is set to 65 mm, and the outer radius of the curved edge portion connecting the top plate portion and the longitudinal walls is set to 8.0 mm. Furthermore, regarding the dimensions of the second plate P constituting the reinforcing component in the above cross-section, the length of the top plate portion is set to 90 mm, and the distance from the rounded corner termination of the longitudinal walls to the end of the plate is set to 22-57 mm. Additionally, the inner radius of the curved edge portion connecting the top plate portion and the longitudinal walls is set to 5.0 mm.

[0121] In this embodiment, when the intersection point obtained by extending the straight section of the top plate portion and the longitudinal wall portion is defined as U, the line length L2 of the longitudinal wall portion of the first plate L, which corresponds to the main body component, is defined as the line length between the connection point U and the end point of the first plate L. Furthermore, the line length P2 of the longitudinal wall portion of the second plate P, which corresponds to the reinforcing member, is defined as the line length from the boundary point E between the top plate portion and the curved ridge portion to the end point F of the plate.

[0122] The first sheet L constituting the main component is made of galvanized steel sheet with a tensile strength of 980 MPa and a thickness of 1.4 mm. The second sheet P constituting the reinforcing component is made of cold-rolled steel sheet with a tensile strength of 1470 MPa and a thickness of 1.6 mm.

[0123] Table 4 shows a list of tests No. 5 to 8 of this embodiment 2.

[0124] [Table 4]

[0125] Figure 14 This plot shows the ratio X of the longitudinal wall length to the angle Y of the longitudinal wall in experiments No. 5-8 of Embodiment 2. Additionally, Figure 15 The cross-sectional views show the molding and demolding of Experiments No. 5 to 8 of Embodiment 2.

[0126] In Experiment No. 5, the length of the longitudinal wall portion of the first plate L, corresponding to the main component, was set to 70 mm, and the length of the longitudinal wall portion of the second plate P, corresponding to the reinforcing component, was set to 28 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second plate P relative to that of the first plate L was X = 0.40. At this time, the angle Y of the longitudinal wall portion derived from condition (2) was Y ≥ 132 degrees. However, Experiment No. 5 set the angle Y of the longitudinal wall portion to 60 degrees, thus failing to satisfy condition (2), resulting in separation during molding.

[0127] In Experiment No. 6, the length of the longitudinal wall portion of the first plate L, corresponding to the main component, was set to 70 mm, and the length of the longitudinal wall portion of the second plate P, corresponding to the reinforcing component, was set to 42 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second plate P to that of the first plate L was X = 0.60. At this time, the angle Y of the longitudinal wall portion derived from condition (2) was Y ≥ 93 degrees. However, Experiment No. 6 set the angle Y of the longitudinal wall portion to 60 degrees, thus failing to satisfy condition (2), resulting in separation during molding.

[0128] In Experiment No. 7, the length of the longitudinal wall portion of the first plate L, corresponding to the main component, was set to 70 mm, and the length of the longitudinal wall portion of the second plate P, corresponding to the reinforcing component, was set to 56 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second plate P relative to that of the first plate L is X = 0.80. At this time, the angle Y of the longitudinal wall portion derived from condition (2) is Y ≥ 54 degrees. Because Experiment No. 7 sets the angle of the longitudinal wall portion to 60 degrees, condition (2) is satisfied, and separation does not occur during molding.

[0129] In Experiment No. 8, the length of the longitudinal wall portion of the first plate L, which corresponds to the main component, is set to 70 mm, and the length of the longitudinal wall portion of the second plate P, which corresponds to the reinforcing component, is set to 63 mm. Therefore, the ratio X of the length of the longitudinal wall portion of the second plate P relative to that of the first plate L is X = 0.90. At this time, the angle Y of the longitudinal wall portion derived from condition (2) is Y ≥ 35 degrees. Because Experiment No. 8 sets the angle Y of the longitudinal wall portion to 60 degrees, condition (2) is satisfied, and separation does not occur during molding.

[0130] The embodiments of the present invention have been described above, but the forming method of the overlapping member of the present invention and the overlapping member of the present invention formed by stamping using the forming method are not limited to the above embodiments. The present invention can be appropriately modified within the scope of the claims. For example, the overlapping member of the present invention is not limited to automobile body, but may also be used for the body of two-wheeled vehicles, railway vehicles, etc.

[0131] Industrial applicability

[0132] Thus, according to the forming method of the overlapping member of the present invention, and the overlapping member of the present invention formed by stamping using this forming method, the region of the top plate portion of the joining blank corresponding to the main body and the reinforcing member is clamped by a blank holder and a punch. Then, the overlapping member is integrally formed directly from the joining blank by stamping. At this time, the first and second plates in the regions not clamped by the blank holder and the punch during forming will not separate. Therefore, it is possible to prevent gaps from forming between the main body and the reinforcing member after demolding, and to avoid degradation of the performance of the overlapping member and assembly obstacles.

[0133] Label Explanation

[0134] The boundary point between the top plate portion and the curved edge portion of E (the first plate L).

[0135] End point F (of the first plate L)

[0136] L First Board Material

[0137] Linear length of L1 (equivalent to the longitudinal wall portion of the first plate L in the first method)

[0138] L2 (equivalent to the longitudinal wall portion of the first plate L in the second method) line length

[0139] L O (Line length from the end of the top plate of the first sheet metal L to the point where the shoulder of the stamping die T2 initially contacts the first sheet metal L)

[0140] L H (Height of the main component)

[0141] L ILinear length (per unit length of board in the horizontal direction)

[0142] L M (The linear length of the uncrushed area of ​​the first plate L, i.e., the total linear length of the curved portion and its extension excluding the top plate portion)

[0143] L P (Line length from the end of the top plate of the first plate L to the contact point between the first plate L and the stamping die T2)

[0144] O (the shoulder of the die T2 initially contacts the first sheet metal L) position (origin).

[0145] P Second Board

[0146] Linear length of P1 (equivalent to the longitudinal wall portion of the second plate P in the first method)

[0147] Linear length of P2 (equivalent to the longitudinal wall portion of the second plate P in the second method)

[0148] S (the intersection point obtained by extending the straight section of the longitudinal wall of the first plate L and the flange)

[0149] T1 punch die

[0150] T2 stamping die

[0151] T3 pressing die

[0152] U (the intersection point obtained by extending the straight section between the top plate portion and the longitudinal wall portion of the first plate L)

[0153] X (equivalent to the ratio of the linear length of the longitudinal wall portion of the second plate P to the linear length of the longitudinal wall portion of the first plate L)

[0154] Y (the vertical angle of the longitudinal wall of the overlapping member relative to the top plate)

[0155] z (horizontal distance from the center of the component, originating at point O)

[0156] θ (the tilt angle of the first sheet L at the contact point between the first sheet L and the die T2)

[0157] f(z) is the deflection in the vertical direction at the distance z between the first plate L and the second plate P.

Claims

1. A method for forming overlapping components, characterized in that, The overlapping member is formed by overlapping a reinforcing member with a U-shaped or L-shaped cross-section, which has a top plate portion and longitudinal wall portion interconnected by curved ridge portions, inside a main body portion having a hat-shaped cross-section. The overlapping member is integrally formed by stamping from a joining blank formed by overlapping and joining a metal sheet constituting the main body portion (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet), with the area corresponding to the top plate portion of the main body portion and the reinforcing member clamped in the joining blank. In the cross-section of the overlapping member orthogonal to the curved ridge portion, the line length of the region of the second plate corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first plate from the end of the region corresponding to the top plate portion of the main body member to the contact position where it contacts the shoulder of the die when the die surface obtained by extending the forming surface of the flange portion of the punch die in the stamping forming of the joining blank using a pair of punch dies and a die is in contact with the plate end of the first plate.

2. The forming method of the overlapping component according to claim 1, characterized in that, In the cross section of the overlapping member that is orthogonal to the curved ridge, when the ratio of the line length of the longitudinal wall portion of the second plate corresponding to the reinforcing member to the line length of the region of the longitudinal wall portion of the first plate corresponding to the main body member is set as X, the standing angle Y (degrees) of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the following formula (1). [Mathematical Expression 1] 。 3. A method for forming overlapping components, characterized in that, The overlapping member is formed by overlapping a reinforcing member with a U-shaped or L-shaped cross-section, which has a top plate portion and longitudinal wall portion interconnected by curved ridge portions, inside a main body component having a U-shaped cross-section. The overlapping member is integrally formed by stamping from a joining blank formed by overlapping and joining a metal sheet constituting the main body component (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet), with the area corresponding to the top plate portion of the main body component and the reinforcing member clamped in the joining blank. In the cross-section of the overlapping member orthogonal to the curved ridge portion, the line length of the region of the second plate corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first plate from the end of the region corresponding to the top plate portion of the main body member to the contact position where it contacts the shoulder of the die during the stamping of the joining blank using a pair of punches and dies.

4. The forming method of the overlapping component according to claim 3, characterized in that, In the cross section of the overlapping member that is orthogonal to the curved ridge, when the ratio of the line length of the region of the second plate corresponding to the longitudinal wall portion of the reinforcing member to the line length of the region of the first plate corresponding to the longitudinal wall portion of the main body portion is set as X, the standing angle Y (degrees) of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the following formula (2). [Mathematical Expression 2] Among them, 0 <Y≤90。 5. An overlapping component, characterized in that, The overlapping member is formed by overlapping a reinforcing member with a U-shaped or L-shaped cross-section, which has a top plate portion and longitudinal wall portion interconnected by curved ridge portions, inside a main body portion having a hat-shaped cross-section. This is achieved by stamping a joining blank formed by overlapping and joining a metal sheet constituting the main body portion (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet), with the area corresponding to the top plate portion of the main body portion and the reinforcing member clamped in the joining blank. In the cross-section of the overlapping member orthogonal to the curved ridge portion, the line length of the region of the second plate corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first plate from the end of the region corresponding to the top plate portion of the main body member to the contact position where it contacts the shoulder of the die when the die surface obtained by extending the forming surface of the flange portion of the punch during the stamping process of the joining blank is in contact with the end of the first plate.

6. The overlapping member according to claim 5, characterized in that, In the cross section of the overlapping member that is orthogonal to the curved ridge, when the ratio of the line length of the region of the second plate corresponding to the longitudinal wall portion of the reinforcing member to the line length of the region of the first plate corresponding to the longitudinal wall portion of the main body portion is set as X, the standing angle Y of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the following formula (1). [Mathematical Expression 1] 。 7. An overlapping component, characterized in that, The overlapping member is formed by overlapping a reinforcing member with a U-shaped or L-shaped cross-section, which has a top plate portion and longitudinal wall portion interconnected by curved ridge portions, inside a main body component having a U-shaped cross-section. This overlapping member is integrally formed by stamping from a joining blank formed by overlapping and joining a metal sheet constituting the main body component (i.e., a first sheet) and a metal sheet constituting the reinforcing member (i.e., a second sheet), with the area corresponding to the top plate portion of the main body component and the reinforcing member clamped in the joining blank. In the cross-section of the overlapping member orthogonal to the curved ridge portion, the line length of the region of the second plate corresponding to the curved ridge portion and the longitudinal wall portion of the reinforcing member is set to be greater than or equal to the line length of the first plate from the end of the region corresponding to the top plate portion of the main body member to the contact position where it contacts the shoulder of the die during the stamping of the joining blank using a pair of punches and dies.

8. The overlapping member according to claim 7, characterized in that, In the cross section of the overlapping member that is orthogonal to the curved ridge, when the ratio of the line length of the region of the second plate corresponding to the longitudinal wall portion of the reinforcing member to the line length of the region of the first plate corresponding to the longitudinal wall portion of the main body portion is set as X, the standing angle Y (degrees) of the longitudinal wall portion of the overlapping member relative to the top plate portion satisfies the following formula (2). [Mathematical Expression 2] Among them, 0 <Y≤90。 9. A method for manufacturing an automotive component, comprising the overlapping member according to any one of claims 5 to 8, wherein, The process includes forming the overlapping member using the forming method of any one of claims 1 to 4.

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