Structural member and manufacturing method thereof

Abstract

To provide a manufacturing method for a structural member capable of bending a material while preventing interference of excess material. [Solution] A manufacturing method for a structural member (10) includes a preparation step and a bending step. In the preparation step, a raw material (M) is prepared. The raw material (M) includes a web (11) and a flange (12). The flange (12) is continuous with the side edge of the web (11). In the bending step, the raw material (M) is bent so that the web (11) is on the outside when viewed from the flange (12) side, while a portion of the flange (12) is caused to protrude outward from the raw material (M) as an excess part (121).

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to structural members and methods of manufacturing the same. [Background technology]

[0002] For example, channel steel and angle steel are known as structural members used in the frames of exterior walls (non-load-bearing walls) of houses. These structural members generally include a web extending in the longitudinal direction of the structural member and a flange continuous with the side edge of the web.

[0003] Some structural members are bent into an L-shape. L-shaped structural members are manufactured by preparing two pieces of material, such as channel steel or angle steel, arranging these pieces in an L-shape, and joining their ends together. The ends of the materials are joined by, for example, welding, riveting, or crimping.

[0004] Alternatively, L-shaped structural members can be manufactured by bending channel or angle steel materials. In this case, a notch is formed in the flange of the material, the material is bent at the notch, and then both end faces of the notch are welded together.

[0005] However, these manufacturing methods require processes for forming notches in the materials and joining the materials together or at the notched portions, which complicates the manufacturing process of the structural components and increases the manufacturing costs of the structural components. Furthermore, when welding is used as a joining method, welding fumes can be generated, potentially worsening the working environment. Furthermore, if the materials are made of plated steel sheets, welding can remove the plating, potentially compromising the rust resistance of the structural components. Therefore, repair processes may be required after welding.

[0006] In contrast, Patent Documents 1 and 2 propose methods for manufacturing an L-shaped structural member by subjecting a material to plastic processing. In the manufacturing methods described in Patent Documents 1 and 2, a die is used to perform plastic processing on a material, such as channel steel, including a pair of front and rear rotary dies, a bending punch disposed above the rotary die, and a pair of left and right pre-bending punches disposed to the sides of the rotary die. In Patent Documents 1 and 2, the pre-bending punches are pressed against both flanges of the material placed on the rotary die, thereby pre-bending each flange. Then, a bending punch having a V-groove at a predetermined angle is pressed from above into the material on the rotary die. At this time, the rotary die rotates along the V-groove of the bending punch, and portions of each flange are folded inward of the material along the bend lines formed by the pre-bending. This results in the formation of an L-shaped structural member.

[0007] Patent Document 3 proposes a method for manufacturing an L-shaped structural member by forming holes in each flange of a channel steel material and then bending the material. In the manufacturing method of Patent Document 3, holes are formed in the portion of each flange of the material that is closest to the web. Then, with the flanges held between dies inside and outside the material, a thrust die is used to push the hole portion of the flange from the outside to the inside of the material, thereby folding the material into an L shape while folding part of the flange into the inside of the material. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-167787 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-170473 [Patent Document 3] Japanese Patent Application Publication No. 6-262267 Summary of the Invention [Problem to be solved by the invention]

[0009] In the manufacturing methods described in the patent documents, when a material is bent to form an L-shaped structural member, a portion of the flange is folded inside the material as excess material. In this case, depending on the shape of the material, bending can be difficult. For example, when the flange height is large relative to the web width or when the material is bent at a relatively small angle, the excess material of the flanges is likely to interfere with each other inside the material. When excess material interferes, bending the material becomes difficult.

[0010] An object of the present disclosure is to provide a method for manufacturing a structural member that can bend a material while preventing interference with excess material. [Means for solving the problem]

[0011] The manufacturing method of a structural member according to the present disclosure includes the steps of preparing a material including a web and a first flange continuous with the side edge of the web, and bending the material so that the web is on the outside of the bent portion when viewed from the first flange side, while causing a portion of the first flange to extend outward from the material as excess material. [Effects of the Invention]

[0012] According to the manufacturing method of a structural member according to the present disclosure, the material can be bent while preventing interference with the excess material. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of a structural member according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the structural member shown in FIG. [Figure 3A] FIG. 3A is a schematic view for explaining a manufacturing method of a structural member according to an embodiment. [Figure 3B] FIG. 3B is a schematic view for explaining the manufacturing method of the structural member according to the embodiment. [Figure 3C] FIG. 3C is a schematic view for explaining the manufacturing method of the structural member according to the embodiment. [Figure 3D]FIG. 3D is a schematic view for explaining the manufacturing method of the structural member according to the embodiment. [Figure 3E] FIG. 3E is a schematic view for explaining the manufacturing method of the structural member according to the embodiment. [Figure 3F] FIG. 3F is a schematic view for explaining a manufacturing method of a structural member according to an embodiment. [Figure 3G] FIG. 3G is a schematic view for explaining the manufacturing method of the structural member according to the embodiment. [Figure 3H] FIG. 3H is a schematic view for explaining the manufacturing method of the structural member according to the embodiment. [Figure 3I] FIG. 3I is a schematic view for explaining the manufacturing method of the structural member according to the embodiment. [Figure 4A] FIG. 4A is a schematic diagram for explaining the dimensional relationship between the various parts of a structural member according to an embodiment. [Figure 4B] FIG. 4B is a schematic diagram for explaining the dimensional relationship between the various portions of the structural member according to the embodiment. [Figure 5] FIG. 5 is a perspective view showing a structural member according to a modified example of the embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining a method for manufacturing the structural member shown in FIG. [Figure 7] FIG. 7 is a perspective view showing a structural member according to another modified example of the embodiment. [Figure 8] FIG. 8 is a perspective view showing a structural member according to yet another modified example of the embodiment. [Figure 9] FIG. 9 is a perspective view showing a structural member according to yet another modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] A manufacturing method for a structural member according to an embodiment includes the steps of preparing a raw material including a web and a first flange continuous with the side edge of the web, and bending the raw material so that the web is on the outside of the bent portion when viewed from the first flange side, while causing a portion of the first flange to extend outward from the raw material as excess material (first configuration).

[0015] In the manufacturing method according to the first aspect, the blank is bent while a portion of the first flange is protruding outward as an excess pad. In this case, because the excess pad of the first flange is positioned on the outside of the blank, interference between the excess pad of the first flange and other portions on the inside of the blank does not occur. Therefore, the blank can be bent while preventing interference from the excess pad.

[0016] The manufacturing method according to the first configuration may further include a step of forming a preformed portion having a convex shape on the outside of the material in a part of the first flange before the bending step (second configuration).

[0017] In the second configuration, a preformed portion having a convex shape is formed on the outer side of the blank for the first flange. In this case, an excess pad can be formed on the first flange using the preformed portion as a base point, and the blank can be bent easily and accurately.

[0018] The manufacturing method according to the first or second configuration may further include, after the folding step, a step of folding the excess part and overlapping it with another part of the first flange (third configuration).

[0019] In the third configuration, the excess pad portion of the first flange is bent so as to overlap with other portions, which can prevent the excess pad portion of the first flange from interfering with other members on the outside of the structural member, for example.

[0020] For example, if the excess pad portion rises from the other portions of the first flange, when a force that widens the bending angle acts on the structural member, the force acts substantially perpendicular to the excess pad portion of the first flange, making it relatively easy for the bending angle of the structural member to widen. In contrast, in the third configuration, the excess pad portion of the first flange is bent and overlapped with the other portions of the first flange. In this case, when a force that widens the bending angle acts on the structural member, the force acts substantially parallel to the excess pad portion of the first flange, making it difficult for the bending angle of the structural member to widen. This improves the strength of the structural member.

[0021] In the manufacturing method according to any one of the first to third configurations, the blank may further include a second flange, which is continuous with the side edge of the web on the opposite side to the first flange (fourth configuration).

[0022] In the manufacturing method according to the fourth configuration, when the width of the web is W, the height of the first flange is H, and the bending angle of the structural member after the bending process is α, and α is defined as 180°-2θ, W, H, and θ may satisfy 2H sinθ>W (fifth configuration).

[0023] As described above, when the flange height is large relative to the web width or when the material is bent at a relatively small angle, interference between the flange pads is likely to occur. Specifically, for example, if the structural member is groove-shaped, where the web width is W, the flange height is H, and the bending angle of the structural member is α = 180° - 2θ, if 2H sinθ > W, the flange pads are likely to interfere with each other, making it difficult to bend the material. However, in the manufacturing method according to the embodiment, the pads of the first flange are positioned outside the material. In this case, even when W, H, and θ satisfy 2H sinθ > W, as in the fifth configuration, the pads of the first flange do not interfere with the second flange, and the material can be easily bent.

[0024] The structural member according to the embodiment comprises a web, a first flange, and a bent portion. The first flange is continuous with the side edge of the web. At the bent portion, the structural member is bent so that the web is on the outside of the bent portion when viewed from the first flange side. At the bent portion, a portion of the first flange is disposed on the outside of the structural member as an excess portion (sixth configuration).

[0025] In the structural member according to the sixth configuration, the excess pad portion may be overlapped with another portion of the first flange (seventh configuration).

[0026] The structural member according to the sixth or seventh configuration may further comprise a second flange, which is continuous with the side edge of the web on the opposite side to the first flange (eighth configuration).

[0027] In the structural member according to the eighth configuration, when the width of the web is W, the height of the first flange is H, and the bending angle of the structural member is α, and α is defined as 180°-2θ, W, H, and θ may satisfy 2H sinθ>W (ninth configuration).

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In these drawings, the same or equivalent components are designated by the same reference numerals, and the same description will not be repeated.

[0029] [Structural member configuration] Fig. 1 is a perspective view showing a schematic configuration of a structural member 10 according to this embodiment. Fig. 2 is a cross-sectional view (cross-sectional view taken along II-II in Fig. 1) of the structural member 10. As shown in Figs. 1 and 2, the structural member 10 includes a web 11 and flanges 12 and 13.

[0030] 2, the web 11 includes a web main body 111 and side edges 112 and 113. The side edges 112 and 113 are disposed on both sides of the web main body 111. The web main body 111 may have a substantially linear shape in a cross-sectional view of the structural member 10. The side edges 112 and 113 may each have an arcuate shape that protrudes outward from the structural member 10 in a cross-sectional view of the structural member 10.

[0031] The flanges 12 and 13 are arranged to face each other. The flange 12 is continuous with a side edge 112 of the web 11. The flange 13 is continuous with a side edge 113 of the web 11 on the opposite side of the flange 12. The flanges 12 and 13 may be smoothly connected to the web main body 111 by the side edges 112 and 113, respectively.

[0032] The web 11 has a width W. The width W is the dimension of the web 11 measured on the outer surface of the structural member 10 and is the shortest distance from the boundary between the side edge 112 of the web 11 and the flange 12 (the radius of the side edge 112 on the flange 12 side) to the boundary between the side edge 113 of the web 11 and the flange 13 (the radius of the side edge 113 on the flange 13 side). The flange 12 has a height H. The height H is the dimension of the flange 12 measured on the outer surface of the structural member 10 and is the shortest distance from the web main body 111 to the end (free end) of the flange 12 opposite the web 11. The width W of the web 11 and the height H of the flange 12 can be measured using a vernier caliper or the like. The height H may be greater than or equal to the width W of the web 11 or less than the width W of the web 11. The flange 13 may have a height substantially equal to the height H of the flange 12.

[0033] As shown in FIG. 1 , the structural member 10 includes a bending portion 14. The structural member 10 is bent at the bending portion 14. More specifically, the structural member 10 is bent at the bending portion 14 so that the web 11 is on the outside of the bend when viewed from the flange 12 or 13 side. The structural member 10 is bent, for example, at a bending angle α. The bending angle α is the angle formed between a portion 114 of the web 11 located on one side of the bending portion 14 and a portion 115 located on the other side. The bending angle α is, for example, 90°. However, the bending angle α may be less than 90° or greater than 90°.

[0034] At the bent portion 14, a portion of the flange 12 is disposed on the outside of the structural member 10 as an excess pad portion 121. In the example of this embodiment, the excess pad portion 121 is overlapped with another portion of the flange 12. The excess pad portion 121 is bent from its base so as to follow the surface of the portion of the flange 12 that is disposed on one side or the other side of the excess pad portion 121.

[0035] At the bent portion 14, an excess pad portion 131 is also formed on the other flange 13. In the example of this embodiment, the excess pad portion 131, which is part of the flange 13, is arranged inside the structural member 10. The excess pad portion 131 may be overlapped with another portion of the flange 13, similar to the excess pad portion 121 of the flange 12. In other words, the excess pad portion 131 may be bent from its base so as to follow the surface of the portion of the flange 13 that is arranged on one side or the other side of the excess pad portion 131.

[0036] [Manufacturing methods for structural components] Next, a method for manufacturing the structural member 10 according to this embodiment will be described with reference to Figures 3A to 3I. The method for manufacturing the structural member 10 includes a preparation step, a preforming step, and a bending step.

[0037] (preparation process) Referring to FIG. 3A, in the preparation step, a raw material M, for example, a channel steel, is prepared. The raw material M has an elongated shape. The raw material M includes a web 11 and flanges 12 and 13. In the state of the raw material M, the web 11 is substantially flat and extends in the longitudinal direction of the raw material M. The flange 12 is continuous with a side edge 112 of the web 11. The flange 13 is continuous with a side edge 113 of the web 11 on the opposite side of the flange 12. The flanges 12 and 13 extend in the longitudinal direction of the raw material M along the web 11. The flanges 12 and 13 are each substantially flat and face each other in the width direction of the raw material M.

[0038] (Preforming process) In the preforming step, a prepared material M is preformed. First, an example of a mold 20 used in the preforming step will be described with reference to Fig. 3B. In this embodiment, the mold 20 includes a die 21, a punch 22, and a cam driver 23.

[0039] The die 21 includes a top surface 211, a bottom surface 212, and a molding surface 213. The top surface 211 and the bottom surface 212 are connected by the molding surface 213. The molding surface 213 has a recess 214 formed therein.

[0040] The recess 214 has a substantially triangular shape when viewed from the molding surface 213. The depth of the recess 214 decreases from the top surface 211 toward the bottom surface 212. The recess 214 includes ridges 214a and 214b.

[0041] The ridge portion 214a is the bottom of the recess 214. The ridge portion 214a extends from the top surface 211 of the die 21 toward the bottom surface 212. The ridge portion 214a may or may not reach the bottom surface 212.

[0042] The ridge portions 214b are both edge portions of the recess 214, and are arranged on both sides of the ridge portion 214a when viewed from the molding surface 213 side. Each of the ridge portions 214b extends from the top surface 211 of the die 21 toward the bottom surface 212. The ridge portions 214b may or may not reach the bottom surface 212. The two ridge portions 214b approach each other as they approach the bottom surface 212. The ridge portions 214b may be connected on the ridge portion 214a. The ridge portions 214b are arranged symmetrically with respect to the ridge portion 214a.

[0043] The punch 22 includes a top surface 221, a bottom surface 222, and a forming surface 223. The top surface 221 and the bottom surface 222 are connected by the forming surface 223. The forming surface 223 is a surface that corresponds to the forming surface 213 of the die 21. The forming surface 223 has a protrusion 224.

[0044] The convex portion 224 has a shape corresponding to the concave portion 214 provided on the molding surface 213 of the die 21. The convex portion 224 has a substantially triangular shape when viewed from the molding surface 223 side. The convex portion 224 includes ridge portions 224a and 224b.

[0045] The ridge line portion 224a is the top of the protrusion 224. The ridge line portion 224a is formed on the punch 22 so as to correspond to the ridge line portion 214a in the recessed portion 214 of the die 21. The ridge line portion 224b is formed on the punch 22 so as to correspond to the ridge line portion 214b in the recessed portion 214 of the die 21.

[0046] The die 21 and punch 22 are configured to be relatively close to each other. In this embodiment, the punch 22 is configured to move close to the die 21. The punch 22 is, for example, a cam slider operated by a cam driver 23. In this case, the punch 22 has a sliding surface 225 on the opposite side of the forming surface 223. Corresponding to the sliding surface 225 of the punch 22, the cam driver 23 also has a sliding surface 231. The sliding surfaces 225, 231 are, for example, surfaces inclined with respect to the moving direction of the cam driver 23.

[0047] In the preforming step, the flange 12 of the material M is processed using a mold 20. More specifically, a preformed portion 122 is formed in a part of the flange 12, as shown in Figures 3B to 3D.

[0048] 3B, when forming the preformed portion 122 (FIG. 3D) by the mold 20, the punch 22 is placed inside the material M with the forming surface 223 facing the flange 12. In this embodiment, the punch 22 is placed on the web 11 and its bottom surface 222 contacts the inner surface of the web 11. The die 21 is placed outside the material M with the forming surface 213 facing the flange 12.

[0049] Next, the die 21 and the punch 22 are brought relatively close to each other, and the flange 12 is sandwiched between the die 21 and the punch 22. In this embodiment, the cam driver 23 is brought close to the punch 22 between the flanges 12 and 13. The sliding surface 231 of the cam driver 23 slides on the sliding surface 225 of the punch 22, thereby pushing the punch 22 toward the die 21. A portion of the flange 12 protrudes outside the material M due to a protrusion 224 provided on the forming surface 223 of the punch 22. As shown in FIG. 3C , a portion of the flange 12 is sandwiched between the protrusion 224 of the punch 22 and the recess 214 of the die 21, and the preformed portion 122 is formed.

[0050] 3D, the preformed portion 122 has a shape that is convex outward from the material M. The preformed portion 122 protrudes outward from the material M compared to other portions of the flange 12, that is, on the opposite side from the other flange 13. The preformed portion 122 has a substantially triangular shape when viewed from the side of the material M.

[0051] The preformed portion 122 includes ridge portions 122a and 122b. The ridge portion 122a is the top of the convex preformed portion 122. The ridge portion 122a extends between the end of the flange 12 on the web 11 side and the end (free end) on the opposite side of the web 11. The ridge portion 122a may extend from the free end of the flange 12 to the web 11, but it does not have to reach the web 11.

[0052] The ridge portions 122b are both edge portions of the preformed portion 122 and are arranged on both sides of the ridge portion 122a in a side view of the material M. Each of the ridge portions 122b extends between the end of the flange 12 on the web 11 side and the end (free end) on the opposite side of the web 11. The ridge portions 122b may extend from the free end of the flange 12 to the web 11, but may not necessarily reach the web 11. The two ridge portions 122b approach each other as they move toward the web 11. The ridge portions 122b may be connected on the ridge portion 122a. The ridge portions 122b are arranged symmetrically with respect to the ridge portion 122a.

[0053] In the preforming step, the flange 13 of the material M can also be processed using the mold 20. More specifically, as shown in Figures 3E to 3G, a preformed portion 132 can be formed in a part of the flange 13.

[0054] 3E, in the example of this embodiment, when the preformed portion 132 (FIG. 3G) is formed by the mold 20, the die 21 is disposed inside the material M and the punch 22 is disposed outside the material M. The die 21 is disposed inside the material M with its forming surface 213 facing the flange 13. The die 21 is placed on the web 11, and its bottom surface 212 contacts the inner surface of the web 11. The punch 22 is disposed outside the material M with its forming surface 223 facing the flange 13.

[0055] Next, the die 21 and the punch 22 are brought relatively close to each other, and the flange 13 is sandwiched between the die 21 and the punch 22. In this embodiment, the cam driver 23 is brought close to the punch 22 outside the material M. The sliding surface 231 of the cam driver 23 slides on the sliding surface 225 of the punch 22, and the punch 22 is pushed toward the die 21. A portion of the flange 13 protrudes toward the inside of the material M due to a protrusion 224 provided on the forming surface 223 of the punch 22. As shown in FIG. 3F , a portion of the flange 13 is sandwiched between the protrusion 224 of the punch 22 and the recess 214 of the die 21, and a preformed portion 132 is formed.

[0056] 3G, the preformed portion 132 has a concave shape on the inside of the material M. The preformed portion 132 protrudes toward the inside of the material M, i.e., toward the other flange 12 side, compared to other portions of the flange 13. The preformed portion 132 has a substantially triangular shape when viewed from the side of the material M.

[0057] The preformed portion 132 includes ridge portions 132a and 132b. The ridge portion 132a is the bottom of the concave preformed portion 132. The ridge portion 132a extends between the end of the flange 13 on the web 11 side and the end (free end) on the opposite side of the web 11. The ridge portion 132a may extend from the free end of the flange 13 to the web 11, but does not have to reach the web 11.

[0058] The ridge portions 132b are both edge portions of the preformed portion 132 and are arranged on both sides of the ridge portion 132a in a side view of the material M. Each of the ridge portions 132b extends between the end of the flange 13 on the web 11 side and the end (free end) on the opposite side of the web 11. The ridge portion 132b may extend from the free end of the flange 13 to the web 11, but may not necessarily reach the web 11. The two ridge portions 132b approach each other as they approach the web 11. The ridge portions 132b may be connected on the ridge portion 132a. The ridge portions 132b are provided symmetrically with respect to the ridge portion 132a. The angle formed by each of the ridge portions 132b and the ridge portion 132a is substantially equal to the angle formed by each of the ridge portions 122b and the ridge portion 122a in the preformed portion 122 of the flange 12.

[0059] The formation of the preformed portion 132 in the flange 13 may be performed before or after the formation of the preformed portion 122 in the flange 12, or may be performed simultaneously with the formation of the preformed portion 122 in the flange 12. For example, by preparing a set of the die 21, punch 22, and cam driver 23 for each of the flanges 12 and 13 and using them simultaneously, the preformed portions 122 and 132 can be formed simultaneously.

[0060] (Bending process) 3H and 3I, in the folding process, the material M is folded so that the web 11 is on the outside when viewed from the flange 12 side. In the folding process, the material M is folded while a part of the flange 12 is made to protrude outward from the material M as an excess material portion 121. By folding the material M, the material M becomes the structural member 10.

[0061] The material M can be folded by a known method using a known device. For example, the material M can be folded using a folding device 30 as shown in FIG. 3H. In this embodiment, the folding device 30 includes a punch 31 and a pair of dies 32. The punch 31 is disposed so as to face the dies 32. A V-shaped groove 311 is formed on the surface of the punch 31 facing the dies 32. The dies 32 are disposed inside the material M.

[0062] As shown in FIG. 3I, by pressing the punch 31 against the pair of dies 32, each die 32 rotates so as to follow the grooves 311 of the punch 31. As a result, the material M is bent along the grooves 311 of the punch 31. At this time, a portion of the flange 12 becomes the excess material portion 121 and is folded outside the material M. For example, a portion of the flange 12 is folded outside the material M along the ridge portion 122a (FIG. 3D) of the preformed portion 122.

[0063] When the material M is folded, an excess pad portion 131 is also formed in the flange 13. In this embodiment, a part of the flange 13 becomes the excess pad portion 131 and is folded inside the material M. The part of the flange 13 is folded inside the material M, for example, along the ridge portion 132a (FIG. 3G) of the preformed portion 132.

[0064] (Processing process) The manufacturing method according to this embodiment may further include a step of processing the excess pad portion 121 of the flange 12 after the bending step. In the processing step, the excess pad portion 121 protruding outward from the structural member 10 is folded and overlapped with another portion of the flange 12. In the processing step, the excess pad portion 131 of the flange 13 may also be processed. That is, the excess pad portion 131 protruding inward from the structural member 10 may be folded and overlapped with another portion of the flange 13.

[0065] [effect] In the manufacturing method of the structural member 10 according to this embodiment, when the raw material M is bent so that the web 11 is on the outside of the bend and the free ends of the flanges 12 and 13 are on the inside of the bend, a portion of the flange 12 is made to protrude outward from the raw material M as an excess pad 121. In this case, because the excess pad 121 of the flange 12 is positioned on the outside of the raw material M, there is no interference between the excess pad 121 of the flange 12 and other portions, such as the excess pad 131 of the flange 13, on the inside of the raw material M. Therefore, the raw material M can be bent regardless of the shape of the raw material M. For example, even when the height H of the flange 12 is large relative to the width W of the web 11 or when a structural member 10 with an acute bend angle α is manufactured, the raw material M can be bent without the excess pads 121 and 131 interfering with each other.

[0066] In the manufacturing method of the structural member 10 according to this embodiment, a preforming step is carried out prior to the bending step of the raw material M. In the preforming step, a preformed portion 122 having a convex shape on the outside of the raw material M is formed in a portion of the flange 12 that will become the excess material portion 121. In addition, a preformed portion 132 having a concave shape on the inside of the raw material M is formed in a portion of the flange 13 that will become the excess material portion 131. By forming the preformed portions 122, 132 in advance, the excess material portions 121, 131 are formed on the flanges 12, 13, respectively, using the preformed portions 122, 132 as base points in the bending step. For example, a portion of the flange 12 is folded along at least the central ridge portion 122a of the preformed portion 122 to form the preformed portion 122. Similarly, a portion of the flange 13 is folded along at least the central ridge portion 132a of the preformed portion 132 to form the preformed portion 132. In this case, the raw material M can be easily and accurately bent.

[0067] In this embodiment, the excess pad portion 121 of the flange 12 is bent and overlapped with another portion. In this case, when a force is applied to the structural member 10 to increase the bending angle α, the force acts substantially parallel to the excess pad portion 121 of the flange 12. Similarly, when the excess pad portion 131 of the flange 13 is bent and overlapped with another portion, when a force is applied to the structural member 10 to increase the bending angle α, the force acts substantially parallel to the excess pad portion 131 of the flange 13. This makes it difficult for the bending angle α of the structural member 10 to increase, thereby improving the strength of the structural member 10.

[0068] When excess pad portion 121 is bent and overlapped with other portions of flange 12, it is possible to prevent excess pad portion 121 of flange 12 from interfering with other members, for example, on the outside of structural member 10. Similarly, when excess pad portion 131 is bent and overlapped with other portions of flange 13, it is possible to prevent excess pad portion 131 of flange 13 from interfering with other members.

[0069] FIG. 4A is a view of the structural member 10 as seen from the inside immediately after the bending process. As shown in FIG. 4A, in the structural member 10 immediately after the bending process, an excess pad portion 121 is formed on the flange 12. The excess pad portion 121 protrudes from the other portions of the flange 12 by a protrusion amount A. As shown by the two-dot chain line in FIG. 4A, for example, if the excess pad portion 121 protrudes toward the inside of the structural member 10, the excess pad portion 121 may interfere with the excess pad portion 131 of the other flange 13 depending on the width W of the web 11. For example, if the excess pad portion 131 of the other flange 13 has the same protrusion amount A as the excess pad portion 121 of the flange 12, the excess pad portions 121 and 131 will interfere with each other if 2A exceeds the width W of the web 11.

[0070] FIG. 4B is a development view of the structural member 10, showing the excess pad portions 121 and 131 of the flanges 12 and 13 and their vicinity. In FIG. 4B, the bend lines L1 and L2 of the flange 12 are indicated by dashed lines. The bend line L2 is located on both sides of the bend line L1. In the structural member 10, the excess pad portion 121 (FIG. 4A) is formed by folding a portion of the flange 12 along the bend lines L1 and L2. The bend lines L1 and L2 may or may not coincide with the ridge portions 122a and 122b of the preformed portion 122. For example, the ridge portion 122a of the preformed portion 122 may be located on the bend line L1 but may be shorter than the bend line L1. The ridge portion 122b of the preformed portion 122 does not have to be located on the bend line L2.

[0071] Here, the protrusion amount A of the excess pad portion 121 corresponds to the length of a perpendicular line dropped from the intersection of the bend line L1 and the free end of the flange 12 to one of the bend lines L2. When the angle formed by the bend line L1 and the bend line L2 is θ, the protrusion amount A of the excess pad portion 121 can be calculated using the height H of the flange 12 as A = H sin θ. When the angle formed by the bend line L1 and the bend line L2 is θ, the bending angle α (Figure 1) of the structural member 10 is 180° - 2θ. Therefore, the larger θ is, the smaller the bending angle α of the structural member 10, and the smaller θ is, the larger the bending angle α of the structural member 10.

[0072] When the excess pad portion 121 of the flange 12 and the excess pad portion 131 of the flange 13 are both positioned inside the structural member 10, if 2A = 2H sinθ > W, as described above, there is a high possibility that the excess pad portions 121, 131 will interfere with each other. However, in the structural member 10 according to this embodiment, the excess pad portion 121 of the flange 12 protrudes to the outside of the structural member 10. Therefore, even if the condition 2H sinθ > W is satisfied, the structural member 10 can be manufactured without the excess pad portions 121, 131 interfering with each other.

[0073] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0074] In the above embodiment, the excess pad portion 121 of the flange 12 is disposed on the outside of the structural member 10, while the excess pad portion 131 of the flange 13 is folded inward of the structural member 10. However, as shown in FIG. 5, the excess pad portion 131 of the flange 13 may also be disposed on the outside of the structural member 10. In this case, as shown in FIG. 6, the preformed portion 132 formed on the flange 13 before the bending step can have a convex shape facing outward from the material M, similar to the preformed portion 122 of the flange 12. When forming the convex preformed portion 132 on the flange 13, the mold 20 described in the above embodiment can also be used.

[0075] In the above embodiment, the preformed portions 122, 132 are formed on the flanges 12, 13 of the raw material M before the bending step. However, it is also possible to perform the bending step of the raw material M without forming the preformed portions 122, 132. In other words, the manufacturing method of the structural member 10 does not necessarily have to include the preformed step of the flanges 12, 13.

[0076] In the structural member 10 according to the above embodiment, the excess pad portion 121 of the flange 12 is bent and overlapped with other portions of the flange 12. However, the excess pad portion 121 does not necessarily have to overlap with other portions of the flange 12. As shown in FIG. 7 , the excess pad portion 121 may protrude in a direction intersecting with other portions of the flange 12. In other words, the manufacturing method for the structural member 10 does not have to include a step of treating the excess pad portion 121. Similarly, with respect to the flange 13, the excess pad portion 131 may or may not overlap with other portions of the flange 13.

[0077] The structural member 10 according to the present embodiment includes a single bent portion 14. However, the structural member 10 may include multiple bent portions 14. For example, as shown in FIG. 8, the structural member 10 may be bent at four locations to have a rectangular frame shape as a whole. In this case, one end 15 of the structural member 10 may be joined to the other end 16. The ends 15, 16 of the structural member 10 can be mechanically joined together by, for example, crimping. However, the ends 15, 16 of the structural member 10 do not have to be joined together.

[0078] When the structural member 10 includes multiple bent portions 14, it is sufficient that the excess pad portion 121 of the flange 12 is disposed on the outside of the structural member 10 in at least one of the bent portions 14. In the other bent portions 14, it is preferable that at least one of the excess pad portion 121 of the flange 12 and the excess pad portion 131 of the flange 13 is disposed on the outside of the structural member 10.

[0079] In the above embodiment, the structural member 10 includes the web 11 and the flanges 12 and 13. However, as shown in Fig. 9, the structural member 10 may not include one of the flanges 13. In this case, the material M before the bending process also does not include the flange 13. In other words, the structural member 10 and the material M may be so-called angle iron.

[0080] When the structural member 10 and the material M are channel steel as in the above embodiment, lips may be added to the flanges 12, 13. When the structural member 10 and the material M are angle steel, lips may also be added to the flange 12. In other words, the structural member 10 and the material M may be channel steel with a lip or angle steel with a lip.

[0081] The structural member 10 and the material M are typically made of steel. However, the materials of the structural member 10 and the material M are not limited to this. The structural member 10 and the material M may be made of any metal that can be plastically processed. In addition to steel, the structural member 10 and the material M may be made of, for example, aluminum, copper, titanium, or alloys thereof. The structural member 10 and the material M may have a plating layer. [Explanation of symbols]

[0082] 10: Structural members 11:Web 112,113: Side edge 12: Flange (first flange) 121: Excess meat part 122: Preforming part 13: Flange (second flange) 131: Excess meat part 132: Preforming part 14: Bending part M: Material

Claims

1. A method for manufacturing a structural member, comprising: providing a blank including a web and a first flange contiguous with a side edge of the web; a step of bending the material so that the web is bent outward when viewed from the first flange side while causing a portion of the first flange to protrude outward from the material as an excess portion; A manufacturing method comprising:

2. The method of claim 1 further comprising: a step of forming a preformed portion having a convex shape on the outer side of the material in the part of the first flange before the bending step; A manufacturing method comprising:

3. The method of claim 1 further comprising: a step of folding the excess portion and overlapping it with another portion of the first flange after the folding step; A manufacturing method comprising:

4. The method of claim 1, The blank further includes a second flange contiguous with the side edge of the web opposite the first flange.

5. The manufacturing method according to claim 4, When the width of the web is W, the height of the first flange is H, and the bending angle of the structural member after the bending step is α, and α is defined as α = 180° - 2θ, W, H, and θ satisfy 2H sin θ > W.

6. A structural member, The web and a first flange continuous with a side edge of the web; a bent portion in which the structural member is bent so that the web is bent outward when viewed from the first flange side; Equipped with A structural member, wherein a portion of the first flange is disposed on the outside of the structural member at the bent portion as an excess material portion.

7. 7. The structural member of claim 6, A structural member, wherein the excess material portion overlaps another portion of the first flange.

8. 7. The structural member of claim 6, further comprising: a second flange contiguous with a side edge of the web opposite the first flange;

9. 9. A structural member according to claim 8, A structural member in which, when the width of the web is W, the height of the first flange is H, and the bending angle of the structural member is α, and α is defined as α = 180° - 2θ, W, H, and θ satisfy 2H sin θ > W.

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