Press-molding blank, press-molded component, and method for manufacturing press-molded component

Abstract

The present invention pertains to: a press-molding blank which is for a component and in which two members each having at least a standing wall part and a top plate part are connected in an intersecting manner; a press-molded component obtained by press-molding the blank; and a method for manufacturing the press-molded component.　One embodiment of the present invention is a press-molding blank (integrated blank) obtained by partially overlapping and integrating a first part blank corresponding to a first member and a second part blank corresponding to a second member. In the overlapping portion, at least a portion of the second part blank corresponding to the top plate part is bonded to a portion of the first part blank corresponding to the top plate part of the second member. Further, the second part blank has a protruding part. The protrusion width of the protruding part reduces from the portion corresponding to the top plate toward a portion corresponding to the standing wall part in the second member. The press-molded component is obtained by press-molding the integrated blank. The method for manufacturing the press-molded component uses the integrated blank.

Description

Press-molding blank, press-molded part, and method for manufacturing press-molded part

[0001] The present invention relates to a blank for press molding using a tailored blank, a press-molded part, and a method for manufacturing a press-molded part.

[0002] There is a demand for reducing life cycle GHG (total greenhouse gas emissions over the entire life cycle), particularly in automobiles. With the aim of improving the efficiency of production lines by reducing the number of parts and omitting processes, integration technologies that press-form multiple connected parts or modules into a single part (integrated part) in one go have been attracting attention. Therefore, with the introduction of optimized design, there is an increasing demand for parts to be manufactured by press-forming so-called tailored welded blanks (TWBs), which are press-forming blanks formed by combining and integrating different types of steel sheets within a part. Various TWB press-forming technologies have been proposed in the past (for example, see Patent Document 1).

[0003] A press-molding blank (integrated blank) integrated by TWB is usually manufactured by butt-welding (line-welding) individual blanks (partial blanks) made of steel sheets of different thicknesses and types. As integrated blanks become larger, methods have been proposed for manufacturing an integrated blank by partially overlapping two partial blanks and spot welding the overlapping portions (Patent Documents 2 and 3). With the increasing size of parts and modules and the accompanying trend toward more efficient and cost-effective part manufacturing, part manufacturing by batch press-molding of integrated blanks is attracting increasing attention.

[0004] International Publication No. 2020 / 059804 International Publication No. 2020 / 002335 International Publication No. 2022 / 097058

[0005] When two partial blanks are overlapped and joined (for example, by spot welding, lap welding, or the like) to obtain an integrated blank, the bending strength of the part may be reduced at the overlapping portion of the partial blanks. If the strength is reduced, it may not only affect the design but also the quality of the finished part.

[0006] In particular, when a part in which a first member extending in a first direction is connected to a second member extending in a second direction intersecting the first direction is obtained by press-forming an integrated blank, the bending strength of the second member may decrease at the connection portion between the first member and the second member (hereinafter simply referred to as the connection portion), leaving room for improvement. Here, bending of the connection portion of the second member refers to bending the second member around the connection portion, and may hereinafter simply be referred to as bending of the second member. That is, it means applying a bending moment to the second member around the connection portion of the second member in a plane perpendicular to the plane formed by the first direction and the second direction and including the longitudinal axis of the second member.

[0007] In view of the above problems, the present invention aims to ensure and improve the bending strength of the connection between two members having at least a vertical wall portion and a top plate portion in a part in which the two members are connected so that they intersect, and to provide an integrated blank for press molding for such a part.

[0008] The present inventors have made extensive development efforts to achieve the above object and have obtained the following findings.

[0009] (a) When manufacturing a part in which a first member extending in a first direction is connected to a second member extending in a second direction intersecting the first direction, both the first member and the second member having at least a top plate portion and a vertical wall portion, and the second member is connected so as to abut against the first member, an investigation was conducted into the condition of cracks and wrinkles (hereinafter, cracks and wrinkles are collectively referred to as cracks) that occur at the connection between the two members when an integrated blank formed by overlapping and joining a partial blank for the first member (first partial blank) and a partial blank for the second member (second partial blank) is press-molded.

[0010] As a result, in a bending test of the second member (in which the first member was fixed and an upward load was applied to the opposite end of the second member to generate bending stress at the connection between the second member and the first member), it was confirmed that the expected strength was sometimes not achieved at the connection between the two members (corresponding to the base of the second member). This was thought to be because the connection between the second member and the first member was limited to the end of the connection (hereinafter simply referred to as the end) and the first member, and deformation was concentrated at the connection between the second member and the first member in response to bending of the second member. This was thought to be because the connection was only joined to the first member at the top plate of the second member, and the end of the second member was not joined to the first member, so it was unable to resist the bending of the second member. Furthermore, it was thought that one of the causes of the decrease in strength of the first member was the deformation of the first member at the connection, which was caused by elongation and a reduction in plate thickness during press forming.

[0011] (b) Based on the results of this investigation, we conceived of strengthening the joint between the end of the second member and the first member in order to increase the contribution of the first and second members at the connection to the bending of the second member, and proceeded with development. As a result, we discovered that by providing a protruding portion that partially protrudes from the end of the second member and joining the portion that overlaps the protruding portion with the first member, both the first and second members can contribute to the bending of the second member.

[0012] (c) It was found that the protrusion deforms with the deformation of the second member and also deforms to follow the vertical wall portion of the first member, which may result in complex material flow. To avoid this complex material flow during press forming, it was found that it is effective to join the two partial blanks only to the portion corresponding to the top plate portion, where material flow is minimal, and to join the protrusion and the first member after press forming. Furthermore, it was found that it is effective to decrease the length (protrusion width) of the protrusion of the second member in the direction from the top plate portion toward the vertical wall portion of the second member.

[0013] The present invention was made based on the above findings, and its gist is as follows.

[0014] [1] A blank for press molding of a part, in which a first member extending in a first direction and a second member extending in a second direction intersecting the first direction each have a top plate portion and at least one standing wall portion connected to the top plate portion, and the second member has a portion connected to the first member so as to abut against it, wherein the connected portion of the first member and the second member of the part is formed by partially overlapping a first partial blank corresponding to the first member and a second partial blank corresponding to the second member, and at the overlap portion which is the partially overlapped portion, at least a portion of the portion of the first partial blank corresponding to the top plate portion of the second member is joined, and the end of the second partial blank on the connected portion side has a protruding portion that extends from the top plate portion of the second member along a portion corresponding to the standing wall portion, and the protruding portion has a protruding width (length of the protruding portion) that decreases in the direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the standing wall portion. The part is typically a part in which the second member is connected to the first member so as to abut against a vertical wall portion. [1] The blank for press molding according to [1], preferably, the protruding width decreases at least along a portion corresponding to the vertical wall portion of the second member. [2] The blank for press molding according to [1], more preferably, the protruding portion is absent at an end of the second member corresponding to the vertical wall portion opposite the top plate portion of the second member. [3] The blank for press molding according to [1], wherein the protruding portion has a notch near the boundary between the portion corresponding to the top plate portion of the second member and the portion corresponding to the vertical wall portion. [4] The blank for press molding according to [1] or [2], wherein the protruding width of the protruding portion is constant along the portion corresponding to the top plate portion of the second member. [4] The press-molding blank according to any one of [1] to [3], wherein the protruding portion has a protruding tongue portion in at least one of: (a) a portion along a portion corresponding to a top plate portion of the second member; and (b) a portion along a portion corresponding to a standing wall portion of the second member.[5] The press-molding blank according to any one of [1] to [4], wherein the part is an automotive part. [6] A part having a first member extending in a first direction and a second member extending in a second direction intersecting the first direction, each having a top plate portion and at least one standing wall portion connected to the top plate portion, and a portion where the second member is connected to the first member so as to abut against it, wherein the part where the first member and the second member of the part are connected is constituted by an integrated blank formed by partially overlapping a first partial blank corresponding to the first member and a second partial blank corresponding to the second member, and at the overlapping portion which is the partially overlapped portion, the part of the first partial blank corresponding to the top plate portion of the second member and at least a part of the part of the second partial blank corresponding to the top plate portion of the second member are joined, and the end of the second partial blank on the connected portion side has a protruding portion that protrudes from the top plate portion of the second member along a portion corresponding to the standing wall portion, and the protruding width of the protruding portion decreases in the direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the standing wall portion, and the protruding portion and the first partial blank are joined. The part is typically the part (press-molded part) described in [6] above, in which the second member is connected to the first member so as to abut against the vertical wall portion. Preferably, the part (press-molded part) described in [6] above has a protruding width that decreases at least along a portion corresponding to the vertical wall portion of the second member. More preferably, the part (press-molded part) described in [6] above has no protruding portion at an end of the second member corresponding to the vertical wall portion opposite the top plate portion. [7] The part (press-molded part) described in [6] above has a notch near the boundary between the portion corresponding to the top plate portion of the second member and the portion corresponding to the vertical wall portion. [8] The part (press-molded part) described in [6] or [7] above has a protruding width that is constant along the portion corresponding to the top plate portion of the second member.[9] The part (press-molded part) according to any one of [6] to [8], wherein the protruding portion has a protruding tongue portion in at least one of (a) a portion along a portion corresponding to a top plate portion of the second member, and (b) a portion along a portion corresponding to a standing wall portion of the second member, and the tongue portion and the first member are joined.

[10] The part (press-molded part) according to any one of [6] to [9], wherein the part is an automotive part.

[11] A method for manufacturing a component in which a first member extending in a first direction and a second member extending in a second direction intersecting the first direction each have a top plate portion and at least one standing wall portion connected to the top plate portion, and the second member is connected to the first member so as to abut against the first member, comprising: preparing a first partial blank corresponding to the first member and a second partial blank corresponding to the second member; forming a protrusion at an end of the second partial blank on the side connected to the first member, from the top plate portion of the second member along a portion corresponding to the standing wall portion, the protrusion having a protrusion width (length of the protrusion) decreasing in a direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the standing wall portion; partially overlapping the first partial blank and the second partial blank; forming an integrated blank by joining at least a portion of the first partial blank corresponding to the top plate portion of the second member and at least a portion of the second partial blank corresponding to the top plate portion of the second member at the overlapping portion, which is the partially overlapping portion; press-forming the integrated blank; and thereafter, when further joining the overlapping portion, A method for manufacturing a part (press-molded part), comprising joining at least the protruding portion and the first member. The method for manufacturing a part (press-molded part) described in

[11] above is a method for manufacturing a part (press-molded part) in which the part is typically a part in which the second member is connected to a standing wall portion of the first member so as to abut against it. Preferably, the method for manufacturing a part (press-molded part) described in

[11] above is a method for manufacturing a part (press-molded part) in which the protruding width decreases at least along a portion corresponding to the standing wall portion of the second member. More preferably, the method for manufacturing a part (press-molded part) described in

[11] above is a method for manufacturing a part (press-molded part) in which the protruding portion is absent at an end of the part corresponding to the standing wall portion of the second member opposite the top plate portion of the second member.

[12] A method for manufacturing a part (press-molded part) according to

[11] , wherein the protruding portion has a notch near the boundary between a portion corresponding to the top plate portion and a portion corresponding to the standing wall portion of the second member.

[13] A method for manufacturing a part (press-molded part) according to

[11] or

[12] , wherein the protruding width is constant along a portion corresponding to the top plate portion of the second member.

[14] A method for manufacturing a part (press-molded part) according to any one of

[11] to

[13] , wherein the protruding portion has a protruding tongue portion in at least one of: (a) a portion corresponding to the top plate portion of the second member; or (b) a portion corresponding to the standing wall portion of the second member, and wherein the tongue portion of the second partial blank and the first member are joined after the press forming.

[15] A method for manufacturing a part (press-molded part) according to any one of

[11] to

[14] , wherein the part is an automotive part.

[0015] According to the present invention, a blank for press-molding a part in which two members, each having at least a vertical wall portion and a top plate portion, are connected so as to intersect, and an integrated blank formed by partially overlapping a plurality of partial blanks is press-molded to ensure bending strength at the connection of the members, thereby obtaining a press-molded part that is improved in terms of bending strength.As a result, press-molded parts with ensured bending strength can be produced efficiently and productively, even for large parts with complex shapes.

[0016] Since Figures 10 and 11 span multiple pages, Figure 10 is divided into Figures 10-1 and 10-2, collectively referred to as Figure 10, and Figure 11 is divided into Figures 11-1 to 11-3, collectively referred to as Figure 11. Figure 1 is a schematic diagram of an L-shaped part with an L-shaped cross section. Figure 2 is a schematic diagram of an L-shaped part with a flange, collectively referred to as Figure 11. Figure 3 is a schematic diagram of a T-shaped part with a C-shaped cross section. Figure 4 is a schematic diagram of a T-shaped part with a hat-shaped cross section. Figure 5 is a schematic diagram of an example of an integrated blank according to the present invention corresponding to an L-shaped part with an L-shaped cross section. Figure 6 is a schematic diagram of an example of an integrated blank according to the present invention corresponding to an L-shaped part with a flange, collectively referred to as Figure 10(a). Figure 6(b) corresponds to the part shown in Figure 10(d), and is a schematic diagram illustrating the possibility of cracks and other defects occurring when the protruding portion extends to the vertical wall portion and flange portion of the second member. FIG. 6(a) is a schematic diagram of an overlapping portion of an example of an integrated blank according to the present invention, in which the L-shaped part of the L-section has a notch. FIG. 8 is a diagram showing an example of an L-shaped part of the present invention in which the intersection angle is an acute angle, where FIG. 8(a) is a schematic diagram of the appearance and FIG. 8(b) is a schematic diagram of the integrated blank. FIG. 9 is a schematic diagram showing an example of an L-shaped part of the present invention in which the top plate portion of the second member and the top plate portion of the first member have a step, and the protruding portion of the second member only overlaps the vertical wall portion of the first member. FIG. 9(b) is a schematic diagram showing a case in which the top plate portion of the second member and the top plate portion of the first member have a step, and the protruding portion of the second member overlaps both the top plate portion and the vertical wall portion of the first member. FIG. 9(c) is a diagram showing a case in which the top plate portions of the first member and the second member are the same height, and the protruding portion of the second member overlaps both the top plate portion and the vertical wall portion of the first member. Figure 10 is a schematic diagram showing an example of an L-shaped part with a flanged L-shaped cross section. Figure 10(a) shows a part according to the present invention, showing a case where there is a step between the top plate portion of the second member and the top plate portion of the first member, and the protruding portion of the second member only overlaps the vertical wall portion of the first member. Figure 10(b) shows a part according to the present invention, showing a schematic diagram showing a case where the L-shaped part with an L-shaped cross section of Figure 9(b) is flanged. Figure 10(c) shows a part according to the present invention, corresponding to the integrated blank of Figure 7.FIG. 10(d) corresponds to FIG. 6(b) and is a schematic diagram illustrating the possibility of cracks and other defects occurring when the protruding portion extends to the vertical wall portion and flange portion of the second member. FIG. 11 is a schematic diagram illustrating an example of an L-shaped part having an L-shaped cross section according to the present invention, showing an example of a part in which a tongue portion is installed on the protruding portion. FIG. 11(a) shows an example of an integrated blank. FIG. 11(b) shows an example of a part corresponding to FIG. 11(a). FIG. 11(c) shows an example of an integrated blank in which a notch is installed on the protruding portion of FIG. 11(a). FIG. 11(d) shows an example of a part corresponding to FIG. 11(c). FIG. 11(e) shows an example of an integrated blank in which the protruding portion of FIG. 11(c) is installed so as to extend from the vertical wall portion to the top plate portion of the first member. FIG. 11(f) shows an example of a part corresponding to FIG. 11(e). Figure 12(a) is a schematic diagram showing an example of an L-shaped part with a flanged L-section according to the present invention, with a tongue portion attached to the protrusion. Figure 12(b) shows an example of a hexagonal cross-section tubular T-shaped part in which the first member in Figure 12(a) is a hat-shaped cross-section member, with the parts placed back to back and further stacked one above the other. Figure 13(a) is a schematic diagram of an automotive part that served as the basis for the T-shaped part used in the examples, and Figure 13(b) is a schematic diagram of the T-shaped press-molded part.

[0017] An embodiment of the present invention (hereinafter simply referred to as the present invention) will be described with reference to the drawings.

[0018] FIG. 1 shows an L-shaped component (hereinafter, simply referred to as an L-shaped component based on the top view shape) in which two L-shaped cross-section members, each having a top plate portion and a vertical wall portion connected thereto, are connected to intersect with each other. As can be seen from FIG. 1 , the top plate portion and the vertical wall portion are connected in a direction perpendicular to the longitudinal direction (axial direction) of the components. The L-shaped component shown in FIG. 1 is an integrated component composed of a first member 1 and a second member 2. The first member 1 extends in a first direction 3, and the second member 2 extends in a second direction 4 intersecting the first direction 3. The second member 2 is connected to the first member 1 so as to abut against the vertical wall portion 12 of the first member 1. Both the first member 1 and the second member 2 have an L-shaped cross-section and each have a top plate portion 11, 21 and a vertical wall portion 12, 22 connected to the top plate portion. The L-shaped part shown in FIG. 2 has a first member and a second member of the L-shaped part shown in FIG. 1, and further has a flange portion connected to the opposite side of the top plate portion of the upright wall portion.

[0019] The L-shaped components 5 and 6 shown in Figures 1 and 2 can be used as a base to create a variety of component shapes. For example, as shown in Figure 3, connecting two L-shaped components 5 back to back creates a T-shaped component 7. The first member 1 of the T-shaped component 7 shown in Figure 3 also has a vertical wall on the side opposite the second member 2. However, since this vertical wall can be formed by simple bending during press forming, conventional press forming methods can be applied and there are no particular technical issues. Therefore, the T-shaped component 7 shown in Figure 3 can be combined with the L-shaped component 5 shown in Figure 1 to create a T-shaped component 7 with a C-shaped cross section. Similarly, connecting two L-shaped components 6 with bottom flanges shown in Figure 2 back to back creates a T-shaped component 8 with a hat-shaped cross section as shown in Figure 4.

[0020] Although not shown, a cross-shaped part with a C-shaped cross section can be formed by connecting four L-shaped parts of Fig. 1 back to back on both the first and second members. Similarly, although not shown, a cross-shaped part with a hat-shaped cross section can be formed by connecting four L-shaped parts of Fig. 2 back to back.

[0021] When these integrated components are manufactured by press-forming an integrated blank, there is a risk of cracks occurring at corners where the blank is bent at the connection between the first and second components, particularly at the vertical wall and flange portions of both components, due to complex material flow. For example, corners include the bent portion extending from the vertical wall portion of the first component to the vertical wall portion of the second component, particularly near the intersection of the top plate and vertical wall portion of the second component and the vertical wall portion of the first component, and near the intersection of the vertical wall and flange portion of the first component and the vertical wall and flange portion of the second component. Therefore, because the problem of corner cracks is the same for cross-shaped, T-shaped, and L-shaped components, the countermeasures discussed for the L-shaped component shown in Figures 1 and 2 can be applied to components of various shapes. For these reasons, the present invention will be described below using the L-shaped component shown in Figures 1 and 2 (hereinafter referred to as the "component").

[0022] <Integrated Blank> An integrated blank was prepared for press forming of this part. The integrated blank was a tailored blank (TWB) constructed by partially overlapping a first partial blank corresponding to the first component and a second partial blank corresponding to the second component. The first partial blank is the blank whose main portion will become the first component after press forming. Therefore, it is referred to as the first partial blank corresponding to the first component. Similarly, the second partial blank is the blank whose main portion will become the second component after press forming, so it is referred to as the second partial blank corresponding to the second component. During overlapping, the second partial blank was placed over the first partial blank so that the mating component, i.e., the second component, butted against the connection portion of the first component. For example, Figure 5 shows a schematic diagram of an integrated blank corresponding to the L-shaped cross section of Figure 9(a). Similarly, Figure 6(a) shows a schematic diagram of an integrated blank for the flanged L-shaped cross section of Figure 10(a). These integrated blanks consist of a first partial blank 110 and a second partial blank 120. The first partial blank 110 and the second partial blank 120 are arranged so that a portion 121 of the second partial blank 120 corresponding to the top plate portion of the second member overlaps a portion of the first partial blank corresponding to the top plate portion of the second member. Note that the two-dot chain line in Figure 5 indicates the boundary line (ridge line 116) between the portion 111 corresponding to the top plate portion of the first member and the portion 112 corresponding to the standing wall portion in the first partial blank 110, and similarly indicates the boundary line (ridge line 126) between the portion 121 corresponding to the top plate portion and the portion 122 corresponding to the standing wall portion in the second partial blank. The same applies to figures showing other blanks.

[0023] Here, the portion 121 of the second partial blank corresponding to the top plate portion of the second member refers to the portion of the second partial blank that will become the top plate portion 21 of the second member after press forming. Similarly, the portion of the first partial blank corresponding to the top plate portion of the second member refers to the portion of the first partial blank 110 that will become the top plate portion 21 of the second member after press forming. Similarly, hereinafter, a portion of the first partial blank 110 that will become the standing wall portion 22 of the second member after press forming will be referred to as the "portion of the first partial blank corresponding to the standing wall portion of the second member." Note that the first partial blank and the second partial blank themselves may each be blanks made from a single steel plate, or may be tailored blanks (TWBs) in which the end faces of multiple steel plates are butt-joined.

[0024] To integrate the two partial blanks, the overlapping portion (the overlapping portion 130) of the two blanks is joined. However, if the two partial blanks 110, 120 are joined over the entire overlapping portion 130, the joining can complicate material flow at the vertical wall, flange, and corner portions of the part during press forming, resulting in significant tensile strain and increased susceptibility to cracking. In particular, the material flow is complex at the intersection of the portion of the first partial blank corresponding to the top plate of the second component, the portion corresponding to the vertical wall of the second component, and the portion corresponding to the vertical wall of the first component, making cracking more likely. On the other hand, the portion of the first partial blank 110 corresponding to the top plate of the second component experiences less material flow and is less susceptible to cracking. Therefore, it is preferable to join only the portion of the overlapping portion 130 corresponding to the top plate of the second component to form an integrated blank. The location of the "at least a portion of the overlapping portion 130 corresponding to the top plate of the second component" is not particularly limited, as long as it is within the overlapping portion. Preferably, a portion of the portion where the material flow is small should be selected for joining. The joining area (which may be considered as the number of welding points in the case of spot welding, or the weld length in the case of lap fillet welding) is not particularly limited. The joining area may be set taking into consideration factors such as preventing the joined portion from being damaged during press forming.

[0025] By joining at least a portion of the overlapping portion 130 that corresponds to the top plate portion of the second member in this manner, both partial blanks can exhibit deformation behavior as if they were separate blanks during press forming. In other words, both partial blanks can be freely deformed, thereby preventing cracks.

[0026] The method for joining the two blanks is not particularly limited. For example, joining by welding such as spot welding, lap welding, and lap fillet welding is preferred. In particular, spot welding is preferred from the viewpoint of workability. The type of welding is not particularly limited. Resistance welding, laser welding, and the like may be selected as appropriate. For example, spot welding (resistance welding, laser spot welding) is preferred from the viewpoint of applicability to complex shapes, workability, and efficiency.

[0027] <Protrusion> Furthermore, it has been found that by forming a protrusion 133 at the overlapping portion 130 of the second partial blank 120 on the end of the second partial blank on the side of the portion connected to the first partial blank (hereinafter simply referred to as the end of the second partial blank), and joining this protrusion to the first partial blank after press forming, it is possible to ensure the bending strength of the second member. As illustrated in Figure 5, the protrusion 133 of the second partial blank 120 is located at the end of the second partial blank 120, from a portion along the portion 121 corresponding to the top plate portion of the second member (a portion where at least a portion of the portion 121 corresponding to the top plate portion of the second member extends toward the first member in the second direction (top plate extension portion)) to a portion along the portion 122 corresponding to the standing wall portion of the second member (a portion where at least a portion of the portion 122 corresponding to the standing wall portion of the second member extends toward the first member in the second direction (standing wall extension portion)). That is, the protruding portion 133 of the second partial blank is the end of the second partial blank 120 on the side where it overlaps with the first blank, and is formed along a portion 121 corresponding to the top plate portion of the second member and a portion 122 corresponding to the standing wall portion of the second member. As a result, the protruding portion of the second partial blank is formed by press forming so as to imitate the standing wall portion and top plate portion of the first member. By joining the protruding portion 133 of the second partial blank to the first member after press forming, an integrated part is formed that can ensure the bending strength of the second member.

[0028] 9 shows examples of an L-shaped cross section, with Fig. 9(a) showing a case where there is a step between the top plate portion of the second member and the top plate portion of the first member, and the protruding portion of the second member overlaps only the vertical wall portion of the first member. Fig. 9(b) shows a case where there is a step between the top plate portion 21 of the second member and the top plate portion 11 of the first member, and the protruding portion 133 of the second member overlaps both the top plate portion 11 and the vertical wall portion 12 of the first member. Fig. 9(c) shows a case where the top plate portions 11, 21 of the first member and the second member are the same height (no step), and the protruding portion of the top plate extension of the protruding portion 133 of the second member overlaps the top plate portion 11 and the vertical wall portion 12 of the first member.

[0029] Figure 10 shows an example of an L-shaped cross section with a flange, and Figure 10(a) shows a case where there is a step between the top plate portion 21 of the second member and the top plate portion 11 of the first member, and the protrusion portion 133 of the second member only overlaps the vertical wall portion 12 of the first member.

[0030] 9(a), (b), (c) and 10(a) and (b), a protrusion 133 is formed on the end of the second member (the end of the second member at the connection between the second member and the first member) so as to conform to the vertical wall of the first member, and the first member and the second member become an integrated part. This makes it possible for the entire end of the second member and the first member to resist bending of the second member.

[0031] Although it depends on the shape of the connection between the first and second members, if there is a step between the top plate portion 11 of the first member and the top plate portion 21 of the second member (i.e., if the height of the top plate portion of the first member is higher than the height of the top plate portion of the second member), it is desirable to make the protrusion 133 fit into the standing wall portion 12 of the first member. This is because if the protrusion 133 deforms from the standing wall portion 12 of the first member to conform to the top plate portion 11, the material flow of the protrusion 133 may become complicated. (For example, while FIGS. 9(b) and 10(b) show that the protrusion 133 of the second partial blank overlaps the standing wall portion 12 and the top plate portion 11 of the first member, FIGS. 9(a) and 10(a) show that the protrusion 133 only overlaps the standing wall portion 12 of the first member.)

[0032] On the other hand, Figure 10(d) shows a case where the protruding portion 133 of Figure 10(a) extends from the standing wall portion 22 of the second member to the flange portion 23. In this case, cracks are likely to occur at the flange corner portion A of the protruding portion, and wrinkles are likely to occur at the flange end portion B. This will be described in detail later.

[0033] The length 135 of the protrusion (the length that protrudes from the point on the second partial blank that corresponds to the end of the second member (the length perpendicular to the end); hereinafter referred to as the protrusion width) is not particularly limited. From the viewpoint of joining the first partial blank and the second partial blank at the overlapping portion, it is desirable to ensure a length that allows joining. For example, when joining by spot welding, it is preferable to ensure an area that is at least twice the spot weld diameter, and from this viewpoint, the protrusion width (length of the protrusion) may be, for example, 10 mm or more, preferably 20 mm or more, or 30 mm or more.

[0034] When the protrusion deforms to conform to the top plate portion from the vertical wall portion of the first member, the protrusion width should be determined so that an area is secured that takes into account joining such as welding, as described above, in the part of the protrusion that corresponds to the top plate portion of the first member.

[0035] On the other hand, if the protruding width is too long, the second partial blank will have an irregular shape in order to secure the protruding portion, which will reduce the material yield when cutting it out from the raw material (steel plate).Therefore, it is preferable to set the length of the second partial blank to match the original plate (steel plate).

[0036] The protrusion width 135 preferably decreases from the portion of the second partial blank corresponding to the top plate portion of the second member (simply referred to as the top plate portion 121 of the second partial blank) toward the portion corresponding to the vertical wall portion of the second member (simply referred to as the vertical wall portion 122 of the second partial blank). As described above, the protrusion undergoes complex deformation during press forming because it is molded to conform to the top plate portion and vertical wall portion of the second member as well as the vertical wall portion and top plate portion of the first member. This causes complex material flow in the protrusion, which can lead to cracks and wrinkles. For example, FIG. 10(d) shows a press-formed part in which the protrusion protrudes a uniform length from the top plate portion, vertical wall portion, and flange portion of the second partial blank, as in the blank shown in FIG. 6(b). In this case, the material flow becomes complex at the flange corner portion A and flange end portion B of the protrusion 133, making it more likely to experience large tensile strain. For example, cracks are likely to occur at flange corners A, and wrinkles are likely to occur at flange ends B.

[0037] To avoid these problems, we found that it is effective to reduce the protrusion width toward the portion where the material flow is relatively complex. Preferably, there are no protrusions at the flange corner portion A and flange end portion B. That is, the protrusion width decreases in the direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the vertical wall portion. Preferably, no protrusion is provided at the portion corresponding to the flange portion of the second member. Even more preferably, the protrusion is provided up to the middle of the vertical wall portion of the second member, so that it does not reach the boundary with the flange portion (e.g., FIG. 10(a) , or FIG. 6(a) for an integrated blank). Even if there is no flange portion, it is preferable that the protrusion does not reach the other end of the vertical wall portion (the end opposite the top plate portion) (e.g., FIGS. 9(a), 9(b), and 9(c) , or FIG. 5 for an integrated blank). That is, the protrusion is provided from the top plate portion of the second member to the middle of the vertical wall portion.

[0038] Furthermore, it is preferable that the protruding width of the protruding portion be constant in the portion that corresponds to the top plate portion of the second member (top plate portion 121 of the second partial blank). By making the protruding width constant in the portion that corresponds to the top plate portion of the second partial blank, the protruding portion can be easily formed into a continuous flange shape, and the overlapping area of ​​the first member and the protruding portion can be secured, thereby increasing the strength of the connection portion between the second member and the first member.

[0039] <Notch Portion of Protruding Portion> A portion of the protruding portion may be cut out. As described above, the protruding portion undergoes complex material flow during press forming. In particular, near the boundary between the top plate portion and the vertical wall portion of the second partial blank, the second partial blank deforms in a manner that mimics the deformation of the first partial blank, resulting in complex material flow. Therefore, it has been discovered that it is advantageous to cut out this portion that will be subject to complex material flow in advance. The portion cut out from the protruding portion is designated as the notch portion 134. Figure 7 is a diagram showing the overlapping portion of Figure 5, but illustrates a case in which a notch portion 134 is provided in one location (the boundary between the portion corresponding to the top plate portion and the portion corresponding to the vertical wall portion) of the protruding portion 133. Note that the notch portion 134 is not limited to an actual cutout portion of the blank, but refers to a notched portion where no blank is present.

[0040] The shape of the notch 134 is not particularly limited. For example, a simulation such as FEM (Finite Element Method) can be used to understand the material flow behavior, identify the portion where the strain exceeds a reference value (e.g., the allowable strain of the steel plate material), and designate that portion as the notch. The notch length 138 of the notch 134 (the maximum length in the second direction from the notch end of the top plate extension of the protrusion to the bottom of the notch (see FIG. 7 )) is not particularly limited. It is recommended to set the notch length taking into consideration the workability of the notch. Because complex material flow may occur in portions that are bent during press forming, the notch may extend over the entire protrusion width. For example, the notch length may be 100% or less, 90% or less, 80% or less, 70% or less, 60% or less, or 50% or less of the protrusion width 135 at the notch end of the top plate extension of the protrusion. On the other hand, to obtain the effect of the notch, it is preferable that the protrusion width 135 at the notch end of the top plate extension of the protrusion be 10% or more, 20% or more, 30% or more, or 40% or more.

[0041] As an example, Fig. 7 shows an integrated blank with an L-shaped cross section and a flange, and Fig. 10(c) shows a part obtained by press-forming the same. The second partial blank of the protrusion 133 has a notch 134 near the boundary between the top plate 121 and the vertical wall 122, and the notch is elliptical in shape. There are no particular restrictions on the method for forming the notch, but it is preferable that the bottom of the notch have a relatively large radius of curvature to prevent it from becoming a starting point for cracks or other problems.

[0042] <Tongue Portion> The protruding portion 133 may be provided with one or more tongue-shaped protrusions (tongue portions) 136 that protrude further from the protruding portion 133. That is, the protruding portion 133 may be provided with one or more protruding tongue portions. The tongue portions are formed to conform to the top plate portion and vertical wall portion of the first component after press forming. Therefore, by joining the tongue portions of the second partial blank with the top plate portion and vertical wall portion of the first component after press forming, the bending strength and rigidity of the integrated component can be increased, contributing to ensuring the bending strength of the component. The width of the tongue portions is preferably narrower than the protruding portion so that the tongue portions only undergo simple bending deformation during press forming. This is because the lack of complex material flow behavior can prevent cracks from occurring.

[0043] The location of the tongue portion is not particularly limited. As an example, as shown in FIG. 11( a), the protruding portion 133 of the second partial blank may have tongue portions 136, 137 protruding from at least one of (a) the portion corresponding to the top plate portion of the second member and (b) the portion corresponding to the vertical wall portion of the second member. Because these tongue portions are separated from each other, they are simply bent independently during press forming, preventing defects such as cracks. The part after press forming of the integrated blank shown in FIG. 11( a) is shown in FIG. 11( b).

[0044] The number of tongue portions is not particularly limited. In the example of Fig. 11(a), tongue portions are provided in two locations, but it is not necessary to provide all of these tongue portions; it is sufficient to provide at least one of them. Of course, multiple tongue portions may be provided in each of (a) and (b). When multiple tongue portions are provided, it is desirable to arrange them so that they do not interfere with each other after press forming. This is because mutual interference can cause defects such as wrinkles during press forming.

[0045] As an example of a press-formed part, Figure 11(b) shows a part press-formed from the integrated blank of Figure 11(a). Figure 11(b) shows an example of an L-shaped part with an L-shaped cross section. As can be seen from Figure 11(b), this shows a case where there is a difference in height between the top plate portion 21 of the second member and the top plate portion 11 of the first member. As shown in Figure 11(b), the tongue portion 136 is press-deformed to conform to the top plate portion 11 of the first member 1, and the tongue portion 137 is press-deformed to conform to the standing wall portion 12 of the first member 1.

[0046] Figure 11(c) shows an example of an integrated blank in which a notch is provided in the protruding portion. Figure 11(d) shows a part press-formed from this. Figure 11(e) shows an example of an integrated blank in which a protruding portion is provided from the vertical wall portion to the top plate portion of the first component. Figure 11(f) shows a part press-formed from this. As can be seen from Figures 11(c) to (f), it is advisable to position the tongue portion so that it does not overlap the notch. This is because it is better not to position the tongue portion in a location where the material flow becomes complicated.

[0047] Figure 12(a) shows an example of an L-shaped part with a flanged L-section. As in the case of Figure 11(d), the tongue portion 136 is press-deformed to conform to the top plate portion 11 of the first member 1, and the tongue portion 137 is press-deformed to conform to the upright wall portion 12 of the first member 1. Figure 12(b) shows an example of a tubular T-shaped part with a hexagonal cross section in which hat-shaped cross sections are stacked on top of each other, formed by placing two parts, each having the hat-shaped cross section of the first member shown in Figure 12(a), back to back and then flipping one of the parts over and combining them one on top of the other. It can be seen that the second member 2 and the first member 1 are firmly connected by the protrusion and tongue portion.

[0048] The size of the tongue portion is not particularly limited. As described above, after press forming, the tongue portion of the protruding portion of the second partial blank is formed to conform to the top plate portion or vertical wall portion of the first member. By joining the tongue portion to the top plate portion or vertical wall portion of the first member after press forming, the bending strength and rigidity of the integrated part can be increased, contributing to ensuring the bending strength of the part. Therefore, it is desirable for the tongue portion to have an area large enough to allow for joining. For example, when joining by spot welding, it is desirable for the tongue portion to have a length and width that are approximately twice the spot weld diameter or more (the length of the tongue portion is the maximum length of the tongue portion in the direction protruding from the protruding portion of the second partial blank (the length direction of the tongue portion), and the width of the tongue portion is the maximum length of the tongue portion in the direction perpendicular to the length direction of the tongue portion). The length and width of the tongue portion may be, for example, 10 mm or more, preferably 20 mm or more, or 30 mm or more.

[0049] For example, when joining the tongue portion by lap fillet welding, the length and width of the tongue portion itself can be reduced, but these can be determined appropriately based on whether the part shape allows for a fillet weld allowance and whether a weld length sufficient to ensure the bending strength and rigidity of the part can be obtained. There are no particular limitations on the upper limits of the length and width of the tongue portion. It is preferable to determine these appropriately based on the part shape and the shape of the material from which the second partial blank is formed. Making the second partial blank an irregular shape to ensure the tongue portion not only reduces material yield but also may increase blank processing costs.

[0050] <Intersection Angle Between First and Second Members> The intersection angle between the first and second members, i.e., the intersection angle between the first and second directions, is not particularly limited. FIG. 8 shows a schematic diagram of an L-shaped part in which the intersection angle between the first member 1 and the second member 2, i.e., the intersection angle between the first direction 3 and the second direction 4, is θ. FIG. 8(a) is an external view of the L-shaped part corresponding to FIG. 9(c), and FIG. 8(b) is a schematic diagram of the integrated blank. While FIG. 8 shows an acute angle (90° or less), it may also be an obtuse angle. The lower limit of the intersection angle θ is not particularly limited as long as it is greater than 0°, but it may be set appropriately depending on the processing accuracy of the press molding. Similarly, the upper limit of the intersection angle θ is not particularly limited as long as it is less than 180°. For example, when L-shaped parts corresponding to opposite sides are integrated as shown in FIGS. 3 and 4, the intersection angle of the opposite members becomes an acute angle and is set appropriately depending on the processing accuracy of the press molding. For example, in the case of an L-shaped cross section with a flange portion, FIG. 8(a) may be modified to correspond to FIGS. 10(a) to 10(c), and FIG. 8(b) may be modified to correspond to FIG. 6(a).

[0051] The above has described a press-forming blank for a part having a first member extending in a first direction and a second member extending in a second direction intersecting the first direction, each having a top plate portion and at least one standing wall portion connected to the top plate portion, and a portion where the second member is connected to the first member so as to abut against the first member. That is, the press-forming blank according to the present invention is a blank including a blank in which the first partial blank and the second partial blank for the connected portion are integrated. There may be one or more integrated blanks for the connected portion within the press-forming blank for the entire part, and their arrangement (position within the press-forming blank for the entire part) is not limited.

[0052] Furthermore, in the blank for press molding of the entire part, the joining method of the blanks other than the portion where the first member and the second member are connected is not particularly limited. A tailored blank (TWB) in which the end faces of partial blanks are joined together may be used.

[0053] <Press-Molded Part> A part (press-molded part) obtained by integrally press-molding an integrated blank composed of the first partial blank and the second partial blank described above is an integrated part. As described above, the L-shaped part with an L-shaped cross section shown in FIGS. 1 and 2 is the basic shape, and by combining these parts, the T-shaped part shown in FIGS. 3 and 4 is obtained. By further combining these parts, a cross-shaped part (not shown) can also be obtained. Similarly, a part with a shape combining an L, a T, and a cross, such as a lattice-like part, can be obtained by combining the L-shaped parts shown in FIGS. 1 and 2 to obtain an integrated blank, which can then be press-molded into an integrated part.

[0054] Furthermore, by combining these integrated components by flipping one component over the other, a component with a tubular cross section can be obtained. For example, by combining and joining the T-shaped components shown in Figure 3 one above the other, a T-shaped component with a hexagonal cross section can be obtained. Similarly, by combining and joining the T-shaped components shown in Figure 4 one above the other, a T-shaped component with a hexagonal cross section and flanges can be obtained. Figure 12(b) shows a schematic diagram of a cross-shaped component obtained by combining back-to-back L-shaped components with hat-shaped cross sections as the first component shown in Figure 12(a) and then combining these components one above the other.

[0055] These parts can also be manufactured using the shaped blank according to the invention. That is, a part in which a first member extending in a first direction and a second member extending in a second direction intersecting the first direction each have a top plate portion and at least one standing wall portion connected to the top plate portion, and the second member has a portion connected to the first member so as to abut against it, wherein the part is composed of an integrated blank in which a first partial blank corresponding to the first member and a second partial blank corresponding to the second member are partially overlapped at the portion where the first member and the second member of the part are connected, and at the overlap portion which is the partially overlapped portion, the portion of the first partial blank corresponding to the top plate portion of the second member and at least a portion of the portion of the second partial blank corresponding to the top plate portion of the second member are joined, and the end of the second partial blank on the connected portion side has a protruding portion that extends from the top plate portion of the second member along the portion corresponding to the standing wall portion, and the protruding width of the protruding portion decreases in the direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the standing wall portion, and the part is a part (press-molded part) in which the protruding portion and the first partial blank are joined. Furthermore, if necessary, the protruding width of the protruding portion is constant in the portion corresponding to the top plate portion of the second member, and / or the protruding portion has a notch near the boundary between the portion corresponding to the top plate portion of the second member and the portion corresponding to the standing wall portion, and / or the protruding portion has a protruding tongue portion in at least one of: (a) a portion that runs along the portion corresponding to the top plate portion of the second member; (b) a portion that runs along the portion corresponding to the standing wall portion of the second member, and the part is a press-molded part in which the tongue portion and the first member are joined.

[0056] The part is typically a part (press-molded part) in which the second member is connected to the upright wall portion of the first member so as to abut against the upright wall portion.

[0057] Preferably, the protruding width of the second member is reduced at least along a portion corresponding to the vertical wall portion of the second member (a press-molded part).

[0058] More preferably, the part is a part (press-molded part) that does not have the protrusion at the end of the second member opposite the top plate portion, which is a part corresponding to the standing wall portion of the second member.

[0059] In the conventional method, the first and second members were press-formed separately and then joined to obtain an integrated part, but in this method, an integrated part is obtained by press-forming an integrated blank in a single operation, and it was confirmed that extremely high efficiency in workability was realized. In particular, in the case of a part that combines multiple L-shaped parts, what would have been required was to press-form individual members and then weld them together, but now an integrated part can be obtained by integral press-forming, so the effect is extremely significant.

[0060] Furthermore, the part (press-molded part) according to the present invention can reduce the radius of curvature of the corner between the first and second members. By allowing not only the first member but also the second member itself to resist bending of the second member, the burden on the connection of the first member can be reduced. This makes it easier for the connection of the first member to deform, and as a result, the radius of curvature of the corner between the first and second members can be reduced.

[0061] In conventional press forming using tailored blanks (TWB), the radius of curvature of the corners of the first and second members was at least about 120 mm, but it was confirmed that when the present invention is applied, it is possible to manufacture members with a radius of curvature of 15 mm. For example, in the case of frame members for automobiles, the smaller radius of curvature of the corners increases the capacity to carry parts, etc.

[0062] The use of the parts according to the present invention is not particularly limited. For example, they can be applied to automobile parts. Examples of automobile parts include components of a front module (e.g., a front side member and a cross member), a side sill (rocker) and a floor cross member, a floor tunnel and a floor cross member, and components of a rear under module (e.g., a rear side member and a cross member). When applied to automobile parts, improvements in ease of getting in and out can also be expected. Note that the parts referred to here include parts to which the above-mentioned integrated blank is applied.

[0063] <Method for Manufacturing Component> In the method for manufacturing a component according to the present invention, other than manufacturing the integrated blank described above, known methods can be applied, such as press forming methods and joining methods (for example, welding methods such as spot welding, lap welding, and lap fillet welding). To reiterate, the method for manufacturing a component according to the present invention is as follows.

[0064] - preparing a first partial blank corresponding to a first member and a second partial blank corresponding to the second member; - forming a protrusion at the end of the second partial blank that connects to the first member, along a portion that extends from the top plate portion of the second member to a portion that corresponds to a standing wall portion; - forming the protrusion so that the protrusion width (length of the protrusion) decreases in the direction from the portion that corresponds to the top plate portion of the second member to the portion that corresponds to the standing wall portion; - forming a tongue portion if necessary; - partially overlapping the first blank and the second blank; - at the overlapping portion, which is the partially overlapping portion, joining at least the portion of the first partial blank that corresponds to the top plate portion of the second member and at least a portion of the portion of the second partial blank that corresponds to the top plate portion to form an integrated blank; - press-forming the formed integrated blank; - thereafter further joining the portions that are not joined at the overlapping portion; - at this time, joining at least the protrusion and the first member to obtain a part (press-molded part). Further, if necessary, the method for manufacturing a part (press-molded part) may be such that the protruding portion has a notch near the boundary between a portion corresponding to the top plate portion and a portion corresponding to the standing wall portion of the second member.

[0065] Similarly, if necessary, the method for manufacturing a part (press-molded part) may be such that the protruding width of the protruding part is constant in a portion corresponding to the top plate portion of the second member.

[0066] -Similarly, if necessary, the protruding portion has a protruding tongue portion on at least one of: (a) a portion along a portion corresponding to a top plate portion of the second member, (b) a portion along a portion corresponding to a standing wall portion of the second member, and the tongue portion and the first member are joined together. -If a tongue portion is provided on the protruding portion, the part (press-molded part) can be obtained by joining the tongue portion and the first member (the tongue portion of the first partial blank) after press molding.

[0067] The part is typically a part in which the second member is connected to the upright wall portion of the first member so as to abut against the upright wall portion. This is a method for manufacturing a part (press-molded part).

[0068] Preferably, in the method for manufacturing a part (press-molded part), the protruding width decreases at least in a portion along a portion corresponding to the standing wall portion of the second member.

[0069] More preferably, the method for manufacturing a part (press-molded part) is such that the protrusion is absent at the end of the second member opposite the top plate portion, which is a portion corresponding to the standing wall portion of the second member. Note that the part referred to here is also included in the part (press-molded part) according to the present invention described above. Therefore, the use of the part according to the present invention is not particularly limited. For example, it can be applied to automobile parts.

[0070] The press forming method is not particularly limited. Any known press forming method can be applied. For example, either cold forming or hot forming is acceptable. In hot forming, so-called hot stamp forming (hot stamping) may be applied. Here, hot stamping is a method in which a material is heated in a heating furnace or the like and press-formed at a high temperature. Because the temperature is high, the material softens compared to room temperature, reducing the forming load. Furthermore, when the material is a steel plate, a high-strength formed product can be obtained by heating it to the austenite region and then hardening the mold at the bottom dead center of the press. Conventional hot stamping methods can be applied to the hot stamping method.

[0071] The method of joining the overlapping portion or the portion of the second partial blank that is not joined by the tongue portion after press forming (including the joining of the tongue portion of the first partial blank and the second partial blank) is not particularly limited. For example, joining by welding such as spot welding, lap welding, or lap fillet welding is preferred. In particular, from the viewpoint of workability, joining by spot welding is preferred. The type of welding is not particularly limited. Resistance welding, laser welding, or the like may be selected and determined as appropriate. For example, spot welding (resistance welding, laser welding) is preferred from the viewpoints of applicability to complex shapes, workability, and efficiency.

[0072] By joining the unjoined portions of the overlapping portion of the first and second partial blanks after press forming (including the tongue portion of the first partial blank and the joint of the second partial blank), the joint strength between the first and second parts is increased, improving the bending strength and rigidity of the part. This ensures the bending strength and rigidity of the part, resulting in an improvement in terms of the bending strength of the part.

[0073] A part imitating the T-shaped part with a hat-shaped cross section that is part of the rear under module of an automobile shown in Figure 13(a) (Figure 13(b): a part in which a cross member is connected so that it butts against the vertical wall of a side member) was obtained by press molding. The part specifications are as follows:

[0074] (1) Side member (first member): Hat-shaped cross section Top plate width: 86 mm Vertical wall length: 86 mm Flange width: 40 mm Plate thickness: 2.0 mm Tensile strength: 1180 MPa (2) Cross member (second member): Hat-shaped cross section Top plate width: 86 mm Vertical wall length: 67 mm Flange width: 40 mm Plate thickness: 1.0 mm Tensile strength: 1180 MPa (3) Part specifications Intersection angle between side member and cross member: 90° (4) Press forming (cold working) Hydraulic press forming machine (MPF-7000 manufactured by AIDA Engineering)

[0075] The following blanks were prepared for press forming. Three blanks were prepared for each sample. [Sample 1] Comparative example: A single blank with no overlap (a conventional TWB in which the end faces of the first and second partial blanks are butted together and integrated). [Sample 2] Comparative example: An integrated blank in which the first and second partial blanks are partially overlapped, the second blank has no protrusion, and the top plate of the second partial blank is spot-welded in two places. [Sample 3] Example of the present invention: An integrated blank in which the first and second partial blanks are partially overlapped, and a protrusion is provided at the end of the second partial blank that connects to the first member at the overlapping portion. The protrusion has a notch formed by removing part of the protrusion along its length near the boundary between the top plate and the vertical wall, and a tongue portion is provided on the top plate of the protrusion. The top plate of the protrusion is spot-welded in two places on the top plate of the second partial blank at the overlapping portion. (The part after press forming corresponds to the part in Figure 13(b). The integrated blank corresponds to the integrated blank in Figure 7 combined with its inverted version on the left side.) [Sample 4] Example of the present invention: An integrated blank (corresponding to Figure 6(a)) in which a first partial blank and a second partial blank are partially overlapped, and a protrusion is provided at the end of the second partial blank at the overlapping portion, which corresponds to the connection portion with the first member, and two points on the top plate portion of the second partial blank at the overlapping portion are spot welded.

[0076] Three pieces each of Samples 1 to 4 were press-formed under the same press conditions to obtain T-shaped parts. After press forming, Samples 3 and 4 were spot-welded to the protruding portions (and the tongue portion in the case of Sample 3), and Samples 2, 3, and 4 were also spot-welded at the positions where the flanges of the first and second members overlap (for example, in the case of Figures 10(a) and 12(a) , the positions where flanges 13 and 23 overlap) to join the side member (first member) and the cross member (second member).

[0077] For the resulting T-shaped components, a bending test of the second member was performed. The first member was fixed, and an upward load was applied to the end of the second member opposite the first member, generating bending stress at the connection between the second member and the first member. The maximum load applied to the second member (the load immediately before the connection failed) was measured. Although fine wrinkles were observed in the vertical wall of the side member (first member) for all three of the three samples of Sample 1, the bending test of the second member (cross member) was performed without any changes. The maximum loads for each sample are shown below as indexes, with the maximum load applied to Sample 1 being set at 1.0. [Sample 1] Maximum load index = 1.0 [Sample 2] Maximum load index = 1.1 [Sample 3] Maximum load index = 1.7 [Sample 4] Maximum load index = 1.5 These results demonstrate that the application of the present invention ensures the bending strength of the components without any reduction, improving the bending strength of the components.

[0078] The present invention can be widely used in a wide range of industrial fields, such as the transportation machinery industry (e.g., automobiles), the general machinery industry, and electrical equipment.

[0079] 1 First member 2 Second member 3 First direction 4 Second direction 5 L-shaped part (L-shaped cross section) 6 L-shaped part (L-shaped cross section with flange) 7 T-shaped part (C-shaped cross section) 8 T-shaped part (Hat-shaped cross section) 11 Portion corresponding to top plate portion of first member (top plate portion of first member) 12 Portion corresponding to standing wall portion of first member (standing wall portion of first member) 13 Portion corresponding to flange of first member (flange portion of first member) 21 Portion corresponding to top plate portion of second member (top plate portion of second member) 22 Portion corresponding to standing wall portion of second member (standing wall portion of second member) 23 Portion corresponding to flange of second member (flange portion of second member) 110 First partial blank 111 Portion corresponding to top plate portion of first member of first partial blank (top plate portion of first partial blank) 112 Portion of first partial blank corresponding to first member standing wall portion (standing wall portion of first partial blank) 113 Portion of first partial blank corresponding to first member flange portion (flange portion of first partial blank) 120 Second partial blank 121 Portion of second partial blank corresponding to second member top plate portion (top plate portion of second partial blank) 122 Portion of second partial blank corresponding to second member standing wall portion (standing wall portion of second partial blank) 123 Portion of second partial blank corresponding to second member flange portion (flange portion of second partial blank) 130 Overlapping portion 133 Protruding portion 134 Notch portion 135 Protruding width (length of protruding portion) 136 Tongue portion 137 Tongue portion 138 Notch length

Claims

1. A press-molding blank for a part, wherein a first member extending in a first direction and a second member extending in a second direction intersecting the first direction each have a top plate portion and at least one standing wall portion connected to the top plate portion, and the second member has a portion where it is connected to the first member so as to abut against it, wherein the connected portion of the first and second members of the part is formed by partially overlapping a first partial blank corresponding to the first member and a second partial blank corresponding to the second member, and at the overlap portion where the parts are partially overlapped, at least a portion of the portion of the first partial blank corresponding to the top plate portion of the second member and the portion of the second partial blank corresponding to the top plate portion of the second member are joined, and the end of the second partial blank on the side of the connected portion has a protruding portion that protrudes from the top plate portion of the second member along the portion corresponding to the standing wall portion, and the protruding width of the protruding portion decreases in the direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the standing wall portion.

2. A press-molding blank according to claim 1, wherein the protruding portion has a notch near the boundary between the portion corresponding to the top plate portion and the portion corresponding to the vertical wall portion of the second member.

3. A press-molding blank according to claim 1 or 2, wherein the protruding width of the protruding portion is constant along the portion corresponding to the top plate portion of the second member.

4. A press-molding blank according to any one of claims 1 to 3, wherein the protruding portion has a protruding tongue portion in at least one of the following: (a) a portion that follows the portion corresponding to the top plate portion of the second member; (b) a portion that follows the portion corresponding to the standing wall portion of the second member.

5. A press-molding blank according to any one of claims 1 to 4, wherein the part is an automobile part.

6. A part having a first member extending in a first direction and a second member extending in a second direction intersecting the first direction, each having a top plate portion and at least one standing wall portion connected to the top plate portion, and a portion where the second member is connected to the first member so as to abut against it, wherein the part where the first and second members of the part are connected is constituted by an integrated blank formed by partially overlapping a first partial blank corresponding to the first member and a second partial blank corresponding to the second member, and at the overlapping portion where the first and second members are connected, at least a portion of the portion of the first partial blank corresponding to the top plate portion of the second member is joined, and the end of the second partial blank on the side of the connected portion has a protruding portion that extends from the top plate portion of the second member along the portion corresponding to the standing wall portion, and the protruding width of the protruding portion decreases in the direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the standing wall portion, and wherein the protruding portion is joined to the first partial blank.

7. A press-molded part according to claim 6, wherein the protruding portion has a notch near the boundary between the portion corresponding to the top plate portion and the portion corresponding to the standing wall portion of the second member.

8. A press-molded part according to claim 6 or 7, wherein the protruding width of the protruding portion is constant along the portion corresponding to the top plate portion of the second member.

9. A press-molded part according to any one of claims 6 to 8, wherein the protruding portion has a protruding tongue portion on at least one of: (a) a portion that runs along the portion corresponding to the top plate portion of the second member; (b) a portion that runs along the portion corresponding to the standing wall portion of the second member; and the tongue portion and the first member are joined together.

10. The press-molded part according to any one of claims 6 to 9, wherein the part is an automotive part.

11. A method for manufacturing a part in which a first member extending in a first direction and a second member extending in a second direction intersecting the first direction each have a top plate portion and at least one standing wall portion connected to the top plate portion, and the second member is connected to the first member so as to abut against it, comprising: preparing a first partial blank corresponding to the first member and a second partial blank corresponding to the second member; forming a protrusion at the end of the second partial blank on the side connected to the first member, from the top plate portion of the second member along a portion corresponding to the standing wall portion, the protrusion having a protrusion width (length) decreasing in a direction from the portion corresponding to the top plate portion of the second member toward the portion corresponding to the standing wall portion; partially overlapping the first partial blank and the second partial blank; joining at least a portion of the portion of the first partial blank corresponding to the top plate portion of the second member and at least a portion of the portion of the second partial blank corresponding to the top plate portion of the second member at the overlapping portion, which is the partially overlapping portion, to form an integrated blank; press-forming the integrated blank; and then, when further joining the overlapping portion, A method for manufacturing a press-molded part, comprising joining at least the protrusion and the first member.

12. The method for manufacturing a press-molded part according to claim 11, wherein the protruding portion has a notch near the boundary between the portion corresponding to the top plate portion and the portion corresponding to the standing wall portion of the second member.

13. A method for manufacturing a press-molded part according to claim 11 or 12, wherein the protruding width of the protruding portion is constant along the portion corresponding to the top plate portion of the second member.

14. A method for manufacturing a press-molded part as described in any one of claims 11 to 13, wherein the protruding portion has a protruding tongue portion on at least one of: (a) a portion that follows the portion corresponding to the top plate portion of the second member; (b) a portion that follows the portion corresponding to the standing wall portion of the second member; and the tongue portion of the second partial blank and the first member are joined after the press molding.

15. The method for manufacturing a press-molded part according to any one of claims 11 to 14, wherein the part is an automobile part.

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