Bending device, method for manufacturing structural member using same, and structural member

Abstract

To provide a bending device which can bend a material including a web and a flange continuous to the side edge of the web with good space efficiency.SOLUTION: A bending device (10) is a bending device for bending a material (20) including a web (21) and flanges (22 and 23) continuous to the side edge of the web (21). The bending device (10) includes an outer mold (11), an inner mold (12), and a bending machine (13). The inner mold (12) is arranged so as to face the outer mold (11). The inner mold (12) is structured so as to sandwich the web (21) together with the outer mold (11). The bending machine (13) is arranged adjacent to the outer mold (11). The bending machine (13) is structured so as to press the web (21) toward the side of the inner mold (12) from the side of the outer mold (11).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a folding device, and more particularly to a folding device for folding a material including a web and flanges continuous with side edges of the web. The present disclosure also relates to a method for manufacturing a structural member using the folding device, and to the structural member. [Background technology]

[0002] For example, channel steel and angle steel are known as structural members used in the exterior wall frames of houses, etc. These structural members generally include a web extending in the longitudinal direction of the 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] For example, when bending a material using the manufacturing methods described in Patent Documents 1 and 2, a bending punch with a V-groove and a pair of front and rear rotary dies must be attached to a press. In Patent Documents 1 and 2, the rotary dies rotate as the bending punch descends, and the material is bent along the V-groove of the bending punch and the rotary dies. During this process, the bent portion of the material is lifted by the rotary dies, causing the material to move as a whole. For example, portions of the material on both sides of the bent portion may change from a horizontal state to a state extending diagonally downward, potentially interfering with the press. Interference with the press is particularly likely when the material to be bent is long. Therefore, a large space must be secured in the press to perform the bending process, resulting in poor space efficiency during the bending process. Furthermore, when bending the material multiple times, it is difficult to avoid interference with the press.

[0010] An object of the present disclosure is to provide a folding device that can space-efficiently fold a material that includes a web and a flange that is continuous with the side edge of the web. [Means for solving the problem]

[0011] The folding device according to the present disclosure is a folding device for folding a material including a web and flanges continuous with the side edges of the web. The folding device includes an outer mold, an inner mold, and a folding machine. The inner mold is disposed opposite the outer mold. The inner mold is configured to be able to clamp the web together with the outer mold. The folding machine is disposed next to the outer mold. The folding machine is configured to be able to push the web from the outer mold side toward the inner mold side. [Effects of the Invention]

[0012] The folding device according to the present disclosure can fold a material including a web and a flange continuous with the side edge of the web in a space-efficient manner. [Brief explanation of the drawings]

[0013] [Figure 1]FIG. 1 is a perspective view of a bending device according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the bending device according to the first embodiment. [Figure 3A] FIG. 3A is a diagram illustrating a method for manufacturing a structural member using the bending apparatus shown in FIGS. [Figure 3B] FIG. 3B is a view for explaining a method for manufacturing a structural member using the bending apparatus shown in FIGS. [Figure 3C] FIG. 3C is a view for explaining a method for manufacturing a structural member using the bending apparatus shown in FIGS. [Figure 3D] FIG. 3D is a view for explaining a method for manufacturing a structural member using the bending apparatus shown in FIGS. [Figure 3E] FIG. 3E is a view for explaining a method for manufacturing a structural member using the bending apparatus shown in FIGS. [Figure 3F] FIG. 3F is a view for explaining a method for manufacturing a structural member using the bending apparatus shown in FIGS. [Figure 3G] FIG. 3G is a view for explaining a method for manufacturing a structural member using the bending apparatus shown in FIGS. [Figure 4] FIG. 4 is a diagram showing an example of a structural member manufactured using the bending apparatus shown in FIGS. [Figure 5] FIG. 5 is a partial plan view of a bending device according to the second embodiment. [Figure 6] 6 is a partially enlarged view of the inner mold of the bending device shown in FIG. [Figure 7] FIG. 7 is a diagram for explaining the operation of the bending device shown in FIG. [Figure 8] FIG. 8 is a side view showing an example of a structural member manufactured using the bending apparatus shown in FIG. [Figure 9] FIG. 9 is a front view showing an example of a structural member manufactured using the bending device shown in FIG. [Figure 10]FIG. 10 is a graph showing the depth of sink marks that occurred in the structural members of the examples and the reference example. DETAILED DESCRIPTION OF THE INVENTION

[0014] The folding device according to the embodiment is a folding device for folding a material including a web and a flange continuous with the side edge of the web. The folding device includes an outer mold, an inner mold, and a folding machine. The inner mold is disposed opposite the outer mold. The inner mold is configured to be able to clamp the web together with the outer mold. The folding machine is disposed next to the outer mold. The folding machine is configured to be able to push the web from the outer mold side toward the inner mold side (first configuration).

[0015] When bending a material using the bending device according to the first configuration, the web is first clamped between the outer and inner dies. Then, the bending machine pushes the portion of the web that is not clamped between the outer and inner dies from the outer die side toward the inner die side, thereby folding a portion of the flange into the material and bending the material. At this time, the portion of the material located on one side of the bending portion is fixed by the outer and inner dies, and only the portion of the material located on the other side of the bending portion is pushed and moved by the bending machine. Therefore, compared to conventional manufacturing methods, the bending process can be performed in a smaller space. In other words, the bending device according to the first configuration makes it possible to fold the material in a space-efficient manner.

[0016] The bending device according to the first configuration can be used to fold a material along a horizontal plane, for example. In this case, the material web is held between the outer and inner molds while standing upright on the floor, and the bending machine is moved horizontally to push the portion of the web that is not held between the outer and inner molds toward the inner mold. This allows the material to be folded even when it is difficult to secure sufficient vertical space.

[0017] In the bending device according to the first configuration, the material web can be easily folded by pushing the material web from the outer mold side toward the inner mold side with the folding machine. This bending device does not need to be installed in a large-scale facility such as a press machine. Therefore, the problem of the folded material interfering with the facility can be eliminated.

[0018] In the bending device according to the first configuration, the bending machine may include a bending die. The bending die is configured to be rotatable about a rotation axis. The rotation axis extends in a direction perpendicular to a surface on which the outer die and the inner die are placed (second configuration).

[0019] According to the second configuration, the bending die of the folding machine can be rotated around the rotation axis, and the bending die can press the web of material toward the inner die. In this case, the bending angle of the material can be easily changed by changing the rotation angle of the bending die. Therefore, a single folding device can accommodate various bending angles.

[0020] The bending device according to the first or second configuration may further include a presser die, which is arranged so as to be stacked on the outer die and the inner die (third configuration).

[0021] According to the third configuration, the flange of the material can be pressed by the pressing die during bending of the material, which can prevent the flange from expanding outward when the material is bent by the bending machine.

[0022] In the folding device according to any one of the first to third configurations, the inner mold may include an abutment surface and an inclined surface. The abutment surface is a surface for abutting against the web and faces the outer mold. The inclined surface is continuous with the end of the abutment surface on the folding machine side. The inclined surface is inclined relative to the abutment surface so as to form an acute angle with the abutment surface (fourth configuration).

[0023] According to the fourth configuration, the web can be bent along the corner between the contact surface of the inner mold that contacts the web of the material and the inclined surface that is inclined relative to this contact surface. Furthermore, the portion of the flange that is folded inward of the material can be aligned with the inclined surface of the inner mold. This allows for a sharply shaped bent portion to be formed in the material.

[0024] In the bending device according to the fourth configuration, the inner mold may further include a padding portion. The padding portion is formed on an inclined surface. The padding portion includes a support surface for supporting the web when the material is folded. The support surface is provided on the bending machine side of the contact surface and non-parallel to the contact surface (fifth configuration).

[0025] When folding a material by folding a portion of the flange inside the material, sink marks may occur at the folded portion of the material. More specifically, when the material is folded, the material may flow in an attempt to reduce the energy required for the bending process, causing the web to dent inward at the folded portion. However, with the fifth configuration, not only is the web clamped between the contact surfaces of the outer and inner molds, but the support surface of the padding portion on the inner mold can also support the portion of the web that has been folded toward the inner mold by the bending machine. In other words, with the fifth configuration, the constraint area of ​​the material by the outer and inner molds can be increased. This reduces the flow of the material during the bending process, thereby suppressing the occurrence of sink marks at the folded portion.

[0026] A manufacturing method according to an embodiment is a method for manufacturing a structural member. The manufacturing method includes a preparation step of preparing a material including a web and a flange continuous with a side edge of the web; a preforming step of forming a preformed portion recessed inwardly of the material on the flange; and a folding step of folding the material using a folding device according to any one of the first to fifth configurations after the preforming step. The preformed portion includes a first ridge portion and a second ridge portion. The first ridge portion is the bottom of the preformed portion. The first ridge portion extends from the side edge of the web toward the end of the flange opposite the web. The second ridge portions are both edge portions of the preformed portion. Each of the second ridge portions extends from the end of the first ridge portion on the web side toward the end of the flange so as to become more distant from the first ridge portion as it approaches the end of the flange. The folding process includes a step of clamping the web between an outer mold and an inner mold on one side of the first ridge line, and a step of pushing the web from the outer mold side toward the inner mold side with a folding machine on the other side of the first ridge line, thereby folding the preformed portion into the inside of the material along the first ridge line and the second ridge line (sixth configuration).

[0027] A structural member according to an embodiment includes a web, a flange, and a plurality of folded portions. The flange is continuous with a side edge of the web. At each folded portion, a portion of the flange is folded inward of the structural member, thereby causing the structural member to be folded (seventh configuration).

[0028] A structural member according to an embodiment includes a web, a flange, and a bent portion. The flange is continuous with the side edge of the web. The bent portion is a portion of the structural member that is bent by folding a portion of the flange inward. The depth of the depression formed in the bent portion is 1.0 mm or less, based on a straight line that touches both ends of the web in the width direction at the bent portion when the structural member is viewed in a direction perpendicular to the web (eighth configuration).

[0029] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or equivalent components are designated by the same reference numerals, and the same description will not be repeated.

[0030] First Embodiment [Configuration of bending device] FIG. 1 is a perspective view of a bending device 10 according to a first embodiment. FIG. 2 is a plan view of the bending device 10. The bending device 10 is an apparatus for bending a blank 20 shown by a two-dot chain line in FIGS. 1 and 2. In this embodiment, the blank 20 is a channel steel. The blank 20 includes a web 21 and flanges 22 and 23.

[0031] 1 and 2, the bending device 10 includes an outer die 11, an inner die 12, a folding machine 13, and a pressing die 14. The bending device 10 further includes a support member 15 and a base 16. In FIG. 2, the bending device 10 is shown with the pressing die 14 omitted to avoid complication of the drawing.

[0032] The outer mold 11 is configured so as to be able to clamp the web 21 of the material 20 together with the inner mold 12. The outer mold 11 is supported from its back surface by a support member 15. The back surface of the outer mold 11 is the surface opposite to the inner mold 12 and the web 21 of the material 20. The outer mold 11 is formed integrally with the support member 15, for example. In this embodiment, the outer mold 11 and the support member 15 have an elongated shape.

[0033] The outer die 11 is placed on a base 16. The outer die 11 is detachable from the base 16. When bending the material 20, the outer die 11 is attached to the base 16 by fastening members 17 such as bolts. The outer die 11 may be attached to the base 16 via a support member 15. More specifically, the support member 15 may be fastened to the base 16 by one or more fastening members 17, thereby fixing the outer die 11 supported by the support member 15 to the base 16.

[0034] The outer mold 11 includes a contact surface 111. The contact surface 111 is provided on the outer mold 11 on the opposite side from the support member 15. The contact surface 111 is a surface that comes into contact with the web 21 of the material 20. Although not particularly limited, the contact surface 111 has, for example, a substantially rectangular shape.

[0035] The inner mold 12 is disposed opposite the outer mold 11. The inner mold 12 includes a contact surface 121 and an inclined surface 122. The contact surface 121 faces the contact surface 111 of the outer mold 11. The contact surface 121 is a surface for contacting the web 21 of the material 20 from the opposite side of the outer mold 11. The inclined surface 122 is continuous with the end of the contact surface 121 on the folding machine 13 side. The inclined surface 122 is inclined with respect to the contact surface 121 so as to form an acute angle with the contact surface 121. The contact surface 121 and the inclined surface 122 may each have a substantially rectangular shape. However, the shapes of the contact surface 121 and the inclined surface 122 are not limited thereto.

[0036] The inner mold 12 is placed on a base 16. The inner mold 12 is detachable from the base 16. The inner mold 12 is attached to the base 16 by, for example, fastening members 17 when bending the material 20. The inner mold 12 is fastened to the base 16 by one or more fastening members 17.

[0037] The folding machine 13 is disposed next to the outer mold 11. The folding machine 13 is configured to be able to push the web 21 of the material 20 from the outer mold 11 side toward the inner mold 12 side. The folding machine 13 includes a bending mold 131 and a drive device 132.

[0038] The bending die 131 is placed on the base 16. The bending die 131 is configured to be rotatable around a rotation axis 133. The rotation axis 133 extends in a direction substantially perpendicular to the surface on which the outer die 11 and the inner die 12 are placed. In this embodiment, the rotation axis 133 extends in a direction substantially perpendicular to the surface of the base 16. The bending die 131 is detachable from the base 16.

[0039] The bending die 131 has an elongated shape. When starting the bending process of the material 20, the bending die 131 is arranged in series with the outer die 11. The bending die 131 can press the web 21 of the material 20 by rotating around the rotation axis 133 from a state in series with the outer die 11. A contact surface 131a for contacting the web 21 is provided on the surface of the bending die 131 facing the material 20. When the bending die 131 is in series with the outer die 11, the contact surface 131a can be located on substantially or approximately the same plane as the contact surface 111 of the outer die 11.

[0040] The driving device 132 is configured to operate the bending die 131. The driving device 132 is configured to be able to push the bending die 131 toward the material 20. The driving device 132 is typically an actuator that performs linear motion. The driving device 132 may be, for example, a fluid pressure cylinder such as a hydraulic cylinder or an air cylinder, or may be an electric cylinder. The driving device 132 penetrates the support member 15 and comes into contact with the bending die 131.

[0041] The pressing die 14 is arranged so as to be stacked on the outer die 11 and the inner die 12 when bending the material 20. The pressing die 14 is detachable from the base 16. The pressing die 14 is attached to the base 16 by, for example, fastening members 17. In this embodiment, the pressing die 14 is attached to the base 16 via the outer die 11. For example, the pressing die 14 can be fixed to the base 16 by fastening the pressing die 14 and the outer die 11 to the base 16 by one or more fastening members 17.

[0042] [Manufacturing methods for structural components] 3A to 3G, a method for manufacturing a structural member using the bending apparatus 10 will be described below. The method for manufacturing a structural member includes a preparation step, a preforming step, and a bending step.

[0043] (preparation process) Referring to FIG. 3A , in the preparation step, a raw material 20, which is, for example, a channel steel, is prepared. The raw material 20 includes a web 21 and flanges 22 and 23. The web 21 is flat and extends in the longitudinal direction of the elongated raw material 20. The flange 22 is continuous with one side edge of the web 21. The flange 23 is continuous with the other side edge of the web 21. The flanges 22 and 23 are each flat and face each other in the width direction of the raw material 20. Like the web 21, the flanges 22 and 23 each extend in the longitudinal direction of the raw material 20.

[0044] (Preforming process) In the preforming step, preforming is performed on the prepared material 20. First, the mold 30 used in the preforming step will be described with reference to Fig. 3B. The mold 30 includes a die 31 and punches 32 and 33.

[0045] The die 31 has, for example, a roughly rectangular parallelepiped shape. The die 31 includes a top surface 311 and side surfaces 312 and 313. The top surface 311 has, for example, a rectangular shape in a plan view of the die 31, and extends in the longitudinal direction of the die 31. The side surface 312 is continuous with one side edge of the top surface 311. The side surface 313 is continuous with the other side edge of the top surface 311. Like the top surface 311, the side surfaces 312 and 313 each extend in the longitudinal direction of the die 31.

[0046] Each of the side surfaces 312, 313 has a recess 314. The recess 314 has a substantially triangular shape in a side view of the die 31. The recess 314 includes ridge portions 314a, 314b, and 314c. The ridge portion 314a is the bottom of the recess 314 and has a valley fold shape. The ridge portion 314a extends substantially or approximately in the height direction of the die 31. The ridge portion 314a may be perpendicular to the side edge of the top surface 311 in a side view of the die 31, or may be inclined with respect to the side edge of the top surface 311.

[0047] The ridges 314b and 314c are both edges of the recess 314 and are each formed in a mountain fold shape. The ridges 314b and 314c extend generally in the height direction of the die 31. However, the ridges 314b and 314c are inclined with respect to the ridge 314a, which is the bottom of the recess 314. The angle between the ridge 314b and the ridge 314a is equal to the angle between the ridge 314c and the ridge 314a. The angle between each of the ridges 314b and 314c and the ridge 314a is, for example, 45°. However, the angle between each of the ridges 314b and 314c and the ridge 314a may be less than 45° or greater than 45°.

[0048] The punches 32 and 33 are disposed on both sides of the die 31. The punch 32 is disposed so as to face one side surface 312 of the die 31. The punch 33 is disposed so as to face the other side surface 313 of the die 31.

[0049] Each of the punches 32 and 33 has a protrusion 34 on its surface facing the die 31. The protrusion 34 has a shape corresponding to the recesses 314 formed on the side surfaces 312 and 313 of the die 31. When viewed from the die 31 side, the protrusion 34 has a substantially triangular shape. The protrusion 34 includes ridges 34a, 34b, and 34c. The ridge 34a is the top of the protrusion 34, and the ridges 34b and 34c are the bases of the protrusion 34. The ridge 34a extends substantially parallel to the ridge 314a of the recess 314 of the die 31. The ridges 34b and 34c extend substantially parallel to the ridges 314b and 314c of the recess 314 of the die 31, respectively.

[0050] Referring to FIG. 3C , when preforming the blank 20, first, the blank 20 is placed on the die 31 with the punches 32 and 33 spaced apart from the die 31. At this time, the web 21 of the blank 20 is disposed on the top surface 311 of the die 31, and the flanges 22 and 23 of the blank 20 are disposed along the side surfaces 312 and 313 of the die 31, respectively. In this state, the punches 32 and 33 are brought close to the die 31 and pressed against the flanges 22 and 23 of the blank 20. As a result, portions of the flanges 22 and 23 are pressed between the recessed portion 314 of the die 31 and the protruding portions 34 of the punches 32 and 33. As a result, a preformed portion 24 is formed on each of the flanges 22 and 23, as shown in FIG. 3D .

[0051] The preforming portion 24 is a portion of the flanges 22, 23 that is recessed toward the inside of the blank 20. The preforming portion 24 has a substantially triangular shape in a side view of the blank 20, corresponding to the recess 314 ( FIG. 3B ) of the die 31. The preforming portion 24 includes ridge portions 24a, 24b, and 24c. The ridge portion 24a is the bottom of the recessed preforming portion 24 and has a valley fold shape. The ridge portion 24a extends from the side edge of the web 21 toward the end of the flange 22 or 23 (the side opposite the web 21). The ridge portion 24a may be perpendicular to the side edge of the web 21 or may be inclined relative to the side edge of the web 21 in a side view of the blank 20.

[0052] The ridge portions 24b and 24c are both edge portions of the preformed portion 24 and are each formed in a mountain fold shape. The ridge portions 24b and 24c extend from the end of the ridge portion 24a on the web 21 side toward the end of the flange 22 or 23 (the side opposite the web 21). However, the ridge portions 24b and 24c are inclined with respect to the ridge portion 24a, which is the bottom of the preformed portion 24. The ridge portions 24b and 24c become more spaced apart from the ridge portion 24a as they approach the end of the flange 22 or 23. The ridge portions 24b and 24c extend, for example, from the connection point of the ridge portion 24a to the side edge of the web 21 to the end of the flange 22 or 23.

[0053] The angle between ridge portion 24b and ridge portion 24a is equal to the angle between ridge portion 24c and ridge portion 24a. The angle between each of ridge portions 24b and 24c and ridge portion 24a is, for example, 45°. However, the angle between each of ridge portions 24b and 24c and ridge portion 24a may be less than 45° or greater than 45°. The sum of the angle between ridge portion 24b and ridge portion 24a and the angle between ridge portion 24c and ridge portion 24a, i.e., the angle between ridge portion 24b and ridge portion 24c, is the bending angle of blank 20.

[0054] The preforming step is a step of forming preformed portions 24 including ridge portions 24a, 24b, and 24c as folding lines on the flanges 22 and 23 to make it easier to fold the blank 20 in the subsequent folding step. When folding the blank 20 at multiple locations in the folding step, the preforming step can be repeated multiple times to form multiple preformed portions 24 on each of the flanges 22 and 23. For example, when folding the blank 20 at multiple locations in the folding step to deform it into a frame shape, four preformed portions 24 can be formed on each of the flanges 22 and 23. The preformed portions 24 on the flange 22 are formed at positions corresponding to the preformed portions 24 on the flange 23.

[0055] (Bending process) 3E and 3F, in the folding process, the material 20 after the preforming process is folded by the folding device 10. In this embodiment, an example will be described in which the base 16 is placed on the floor surface and the material 20 is folded substantially along a horizontal plane.

[0056] As shown in Fig. 3E, in the folding process, first, the raw material 20 is placed in the folding device 10. More specifically, the web 21 of the raw material 20 is sandwiched between the outer mold 11 and the inner mold 12 on one side of the ridge line portion 24a, which is the valley fold line of the preformed portion 24. The outer mold 11 and the inner mold 12 are fixed to the base 16 by the fastening member 17 with the web 21 firmly sandwiched between them.

[0057] When the raw material 20 is placed in the bending device 10, the web 21 stands upright relative to the base 16. One flange 22 is in contact with the surface of the base 16. The other flange 23 is positioned above the flange 22. The outer mold 11 abuts the web 21 from the outside of the raw material 20 with the abutment surface 111 on the inner mold 12 side. The inner mold 12 fits between the flanges 22 and 23 and abuts the web 21 from the inside of the raw material 20 with the abutment surface 121 on the outer mold 11 side. The corner of the inner mold 12 between the abutment surface 121 and the inclined surface 122 is positioned at the intersection of the ridge portions 24a and 24b of the preforming portion 24. The inclined surface 122 is positioned so as to follow the ridge portion 24b of the preforming portion 24 in a plan view of the bending device 10.

[0058] When the material 20 is placed in the bending device 10, the contact surface 131a of the bending die 131 of the folding machine 13 can also come into contact with the web 21. The bending die 131 contacts the web 21, for example, from the outside of the material 20. In the bending device 10, the material 20 is placed so that the rotation axis 133 of the bending die 131 is located on the opposite side of the outer die 11 and the inner die 12 across the ridge portion 24a, which is the valley fold line of the preformed portion 24. The pressing die 14 is placed after the web 21 is sandwiched between the outer die 11 and the inner die 12. The pressing die 14 is placed so as to be stacked on the outer die 11 and the inner die 12, and presses the flange 23 from the outside (above) of the material 20. The pressing die 14 is fixed to the outer die 11 and the base 16 by fastening members 17.

[0059] Referring to FIG. 3F, after the blank 20 is placed in the folding device 10, the blank 20 is folded by the folding machine 13. More specifically, the folding machine 13 presses the web 21 toward the inner mold 12 on the side opposite the outer mold 11 and the inner mold 12 with respect to the ridge line 24a (FIG. 3E), which is the valley fold line of the preformed portion 24, thereby folding the blank 20 while folding the preformed portion 24 into the inside of the blank 20 along the ridge lines 24a, 24b, and 24c (FIGS. 3E and 3F). Note that to avoid cluttering the drawings, the presser die 14 is omitted from FIG. 3F and FIG. 3G, which will be described later.

[0060] The drive unit 132 of the folding machine 13 extends, for example, toward the bending die 131. As a result, the bending die 131 is pushed by the drive unit 132 to rotate around the rotation axis 133. As the bending die 131 rotates, the material 20 is pushed by the bending die 131 and begins to bend. The web 21 bends along the corner between the abutment surface 121 and the inclined surface 122 of the inner die 12 (FIG. 3E). The preformed portions 24 of each of the flanges 22 and 23 are folded inward of the material 20 along the ridges 24a, 24b, and 24c (FIGS. 3E and 3F). The portions of the flanges 22 and 23 folded inward of the material 20 come into contact with the inclined surface 122 of the inner die 12 (FIG. 3E).

[0061] After bending the blank 20 to the predetermined bending angle, the drive device 132 and the bending die 131 are stopped and returned to their initial positions. If no preformed portion 24 remains in the blank 20, the blank 20 is removed from the bending device 10. If the preformed portion 24 remains in the blank 20, the blank 20 is shifted so that the preformed portion 24 is positioned near the bending die 131, as shown in FIG. 3G, and the bending process is repeated.

[0062] When the flanges 22, 23 are provided with a plurality of preformed portions 24, it is preferable that the length of the inner mold 12 in the longitudinal direction of the blank 20 be shorter than the distance between adjacent preformed portions 24 in the longitudinal direction of the blank 20. This is because if the length of the inner mold 12 is equal to or greater than the distance between the preformed portions 24, it becomes difficult to remove the inner mold 12 from inside the blank 20 after repeated bending processes. The length of the outer mold 11 in the longitudinal direction of the blank 20 may be longer than the length of the inner mold 12 in the longitudinal direction of the blank 20, or may be equal to the length of the inner mold 12.

[0063] [Structural Members] 4 is a diagram showing an example of a structural member 40 manufactured using the bending apparatus 10. The structural member 40 includes a web 41, flanges 42 and 43, and a plurality of folded portions 44.

[0064] 4 has four bent portions 44. That is, the structural member 40 is bent at four locations. The structural member 40 has a rectangular frame shape as a whole.

[0065] At each of the folded portions 44, portions 421, 431 of the flanges 42, 43 are folded inwardly of the structural member 40. More specifically, portions 421, 431 of the flanges 42, 43 that were preformed portions 24 ( FIG. 3D ) formed on the flanges 22, 23 of the blank 20 are folded and disposed inside the structural member 40. The flanges 42, 43 are continuous with both side edges of the web 41. Therefore, at each of the folded portions 44, the web 41 is bent as the flanges 42, 43 are folded inwardly.

[0066] One end 45 of the structural member 40 may or may not be joined to the other end 46. The ends 45, 46 of the structural member 40 may be mechanically joined by, for example, caulking.

[0067] [effect] When bending the blank 20 using the bending device 10 according to this embodiment, the web 21 is first clamped between the outer mold 11 and the inner mold 12. Then, the bending machine 13 pushes the portion of the web 21 that is not clamped between the outer mold 11 and the inner mold 12 from the outer mold 11 side toward the inner mold 12 side, thereby folding a portion of the flanges 22, 23 into the blank 20 and bending the blank 20. At this time, the portion of the blank 20 that is located on the outer mold 11 and the inner mold 12 side, sandwiching the ridge portion 24a of the preformed portion 24, is restrained by the outer mold 11 and the inner mold 12 and remains stationary. During the bending process of the blank 20, only the portion of the blank 20 that is located on the bending machine 13 side, sandwiching the ridge portion 24a of the preformed portion 24, is pushed and moved by the bending machine 13. Therefore, the blank 20 can be efficiently bent in a small space. Therefore, even a relatively long blank 20 can be bent without worrying about interference with the surrounding area. It is also possible to perform multiple bending processes on the material 20.

[0068] The bending device 10 according to this embodiment can bend the material 20 along a horizontal plane. For example, the base 16 can be placed on the floor, and the bending machine 13 can be moved horizontally. Therefore, even if it is difficult to secure space in the vertical direction, the material 20 can be bent.

[0069] In the bending device 10 according to this embodiment, the blank 20 can be easily bent by moving the bending die 131 toward the inner die 12 using a drive device 132, such as a fluid pressure cylinder. This bending device 10 does not need to be installed in a large-scale facility such as a press machine. This eliminates the problem of the bent blank 20 interfering with the facility.

[0070] In the bending apparatus 10 according to this embodiment, the bending machine 13 includes a bending die 131. This bending die 131 rotates around a rotation axis 133, thereby pressing the web 21 of the material 20 toward the inner die 12. The rotation angle of the bending die 131 can be easily adjusted, for example, by changing the stroke of the drive device 132. By adjusting the rotation angle of the bending die 131, structural members 40 with various bending angles can be manufactured using a single bending apparatus 10.

[0071] The bending device 10 according to this embodiment includes a press die 14. This press die 14 can press the flange 23 when bending the blank 20. The flange 22 is also pressed by the base 16. Therefore, when the preformed portions 24 of the flanges 22, 23 are folded in and the blank 20 is bent, deformation of other portions of the flanges 22, 23 that would otherwise open outward can be suppressed. In other words, the bending process can be performed while maintaining the cross-sectional shape of the blank 20.

[0072] In the bending device 10 according to this embodiment, the inner mold 12 includes a contact surface 121 that contacts the web 21 of the raw material 20, and an inclined surface 122 that is continuous with the contact surface 121. In this case, the web 21 can be bent along the corner between the contact surface 121 and the inclined surface 122. Furthermore, the portions of the flanges 22, 23 that are folded inward of the raw material 20 can be aligned with the inclined surface 122. This allows the raw material 20 to be bent into a sharp shape.

[0073] When the bending device 10 according to this embodiment is used, a structural member 40 having a plurality of bent portions 44 can be manufactured. Each bent portion 44 is formed by bending the preformed portions 24 of the flanges 23, 22 of the blank 20 by plastic processing. In this case, each bent portion 44 hardens due to work hardening, thereby increasing the strength of the structural member 40 as a whole.

[0074] Second Embodiment 5 is a partial plan view of a bending device 10A according to the second embodiment. The bending device 10A has almost the same configuration as the bending device 10 according to the first embodiment. However, the bending device 10A has an inner die 12A that is different from that of the bending device 10 according to the first embodiment.

[0075] 5, the inner mold 12A includes a padding portion 123 in addition to the contact surface 121 and the inclined surface 122. The padding portion 123 is formed on the inclined surface 122. More specifically, the padding portion 123 is provided at the end of the inclined surface 122 on the bending machine 13 side. The padding portion 123 includes an extension surface 123a and a support surface 123b.

[0076] The extension surface 123a is a surface that extends the contact surface 121 of the inner mold 12A toward the bending machine 13. The extension surface 123a extends from the tip of the contact surface 121 toward the bending machine 13. The extension surface 123a is continuous with the contact surface 121 so as to be flush with the contact surface 121, for example. However, there may be a slight step at the boundary between the extension surface 123a and the contact surface 121, or the extension surface 123a may be slightly inclined with respect to the contact surface 121.

[0077] The support surface 123b is a surface for supporting the web when the material is folded by the folding device 10. The support surface 123b is arranged closer to the folding machine 13 than the contact surface 121. The support surface 123b is connected to the contact surface 121 via the extension surface 123a. The support surface 123b is arranged non-parallel to the contact surface 121. The angle between the contact surface 121 and the support surface 123b may be 90°, or may be greater than or less than 90°. The angle between the contact surface 121 and the support surface 123b can be determined depending on the bending angle of the material.

[0078] Fig. 6 is a partially enlarged view of the inner mold 12A, showing the inner mold 12A as viewed from the inclined surface 122 side. Referring to Fig. 6, the padding portion 123 has a shape that narrows from the end of the inclined surface 122 toward the inside. The portion of the padding portion 123 that continues to the support surface 123b (Fig. 5) is formed, for example, in a substantially triangular cone shape (pyramid shape). The padding portion 123 is provided on the inclined surface 122 so as to be substantially symmetrical when the inner mold 12A is viewed from the inclined surface 122 side.

[0079] In this embodiment, both corners 124 of the inner mold 12A on the side of the padding portion 123 are subjected to R-chamfering. That is, each corner 124 of the inner mold 12A is formed so as to have a substantially arc shape when viewed from the inclined surface 122 side.

[0080] FIG. 7 is a diagram illustrating the operation of the bending device 10A. FIG. 7 shows the bending device 10A in a plan view when bending the material 20. Referring to FIG. 7, when the material 20 is bent, a portion 211 of the web 21 facing the contact surface 121 of the inner die 12A is clamped between the outer die 11 and the inner die 12A. Meanwhile, a portion 212 of the web 21 not clamped between the outer die 11 and the inner die 12A is bent by the bending die 131 rotating around the rotation axis 133. At this time, the portion 212 of the web 21 pressed and bent by the bending die 131 is supported by the support surface 123b of the padding portion 123 provided on the inner die 12A. The support surface 123b of the padding portion 123 supports and restrains the web 21 from inside the material 20. This suppresses the flow of the material during the folding process, and suppresses the occurrence of depressions (sink marks) in the web 21 on the folded side of the blank 20.

[0081] When viewed from the side of the inclined surface 122, the padding 123 of the inner mold 12A has a shape that narrows toward the inside of the inclined surface 122. This makes it possible to avoid interference between the preformed portions 24 (FIGS. 3E and 3F) of the flanges 22, 23 and the padding 123 when the preformed portions 24 are folded inside the material 20 as the material 20 is bent. Furthermore, because both corners 124 of the inner mold 12A are rounded by R-chamfering, it is also possible to avoid interference between the folded preformed portions 24 and the inner mold 12A.

[0082] 8 and 9 are diagrams showing an example of a structural member 50 manufactured using the bending apparatus 10A. Fig. 8 is a side view of the structural member 50. Fig. 9 is a front view of the structural member 50.

[0083] 8, structural member 50 includes web 51, flanges 52, and bent portions 53. Similar to structural member 40 according to the first embodiment (FIG. 4), flanges 52 are provided continuously with each of the two side edges of web 51. Bent portions 53 are portions of structural member 50 that are bent by partly folding flanges 52 inward.

[0084] 9 is a view of structural member 50 viewed in a direction perpendicular to web 51, showing a portion of web 51 that corresponds to portion 212 (FIG. 7) on the folding side of web 21 of raw material 20. In FIG. 9, structural member 50 manufactured using bending device 10A according to this embodiment is shown by a solid line, and a structural member in which a sink mark has occurred is shown by a two-dot chain line.

[0085] As shown by the two-dot chain line in Figure 9, when a structural member is manufactured by bending a material such as channel steel, sink marks usually occur at the bent portions of the structural member. That is, a significant depression occurs at the bent portions of the structural member relative to the reference line S. On the other hand, substantially no sink marks occur at the bent portions 53 of the structural member 50 according to this embodiment. That is, the depth (maximum depth) of the depression relative to the reference line S at the bent portions 53 of the structural member 50 is 1.0 mm or less. The reference line S is an imaginary straight line that touches both ends of the web 51 in the width direction at the bent portions 53 when the structural member 50 is viewed along a direction perpendicular to the web 51.

[0086] 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.

[0087] In the bending devices 10, 10A according to the above embodiments, the bending machine 13 includes a bending die 131 and a drive device 132. However, the bending machine 13 does not have to include, for example, the bending die 131. The bending machine 13 can also directly push the web 21 of the material 20 using the drive device 132, which is an actuator that performs linear motion. The bending machine 13 only needs to be configured to be able to push the web 21 from the outer die 11 side toward the inner die 12, 12A side.

[0088] The bending devices 10, 10A according to the above embodiments are provided with a press die 14. However, the bending devices 10, 10A do not necessarily have to be provided with the press die 14. It is also possible to perform the bending process without pressing the flange 23 of the blank 20 with the press die 14.

[0089] In the above embodiment, in the preforming process of the blank 20, the preformed portions 24 are simultaneously formed on both flanges 22, 23. However, it is also possible to form the preformed portions 24 on one of the flanges 22, 23 and then form the preformed portions 24 on the other flange 22, 23.

[0090] In the above embodiment, the blank 20 is a channel steel. However, the material and shape of the blank 20 are not limited thereto. The material of the blank 20 may be any metal that can be plastically processed. In addition to steel, the blank 20 may be made of, for example, aluminum, copper, titanium, or alloys thereof. The blank 20 may have a plating layer. The blank 20 may be angled. That is, the blank 20 may not include one of the flanges 22, 23. Alternatively, the blank 20 may be channeled, with lips attached to the flanges 22, 23. Similarly, the structural members 40, 50 manufactured from the blank 20 may also be angled or channeled with a lip.

[0091] The structural member 40 exemplified in the first embodiment has four bent portions 44 and has a rectangular frame shape as a whole. However, the number of bent portions 44 in the structural member 40 may be three or less, or five or more. By adjusting the bending angle of each bent portion 44, the structural member 40 can also have a shape other than a rectangle.

[0092] The structural member 50 exemplified in the second embodiment above has a single bent portion 53. However, the structural member 50 may be provided with a plurality of bent portions 53. The structural member 50 may also have a polygonal shape, for example, similar to the structural member 40 according to the first embodiment. [Example]

[0093] To confirm the effect of the bending apparatus 10A according to the second embodiment, a structural member 50 was formed by bending a raw material 20 using the bending apparatus 10A (Example). Furthermore, a structural member 50 similar to the Example was formed by bending a raw material 20 using the bending apparatus 10 according to the first embodiment (Reference Example). Then, for each of the Example and Reference Example, the depth of sink marks occurring in the bent portion 53 of the structural member 50 was measured. The sink depth is the depth of a depression occurring in the bent portion 53 due to the bending, and is the maximum depth of the depression relative to the reference line S described in the second embodiment.

[0094] The depth of sink marks that occurred in the structural members 50 of the example and the reference example is shown in Figure 10. Referring to Figure 10, in the structural member 50 of the reference example, the depth of the sink marks that occurred in the bent portion 53 was approximately 3.0 mm. On the other hand, in the structural member 50 of the example, the depth of the sink marks that occurred in the bent portion 53 was 1.0 mm or less. Therefore, it was confirmed that the occurrence of sink marks in the structural member 50 was suppressed by using the bending device 10A equipped with the inner mold 12A provided with the padding portion 123. [Explanation of symbols]

[0095] 10, 10A: Bending device 11: Outer mold 12,12A: Inner mold 121: Contact surface 122: Inclined surface 123: Meat platter 123b: Support surface 13: Bending machine 131: Bending mold 133: Rotation axis 14: Presser mold 20: Material 21:Web 22, 23: Flange 24: Preforming part 24a, 24b, 24c: Ridge line part 40, 50: Structural members 41,51:Web 42, 43, 52: Flanges 44,53: Bending section

Claims

1. 1. A folding device for folding a material including a web and a flange continuous with a side edge of the web, comprising: The outer shape and an inner mold disposed opposite the outer mold and configured to be able to clamp the web together with the outer mold; a folding machine disposed adjacent to the outer mold and configured to be able to push the web from the outer mold side toward the inner mold side; Equipped with The inner mold is a contact surface that faces the outer mold and contacts the web; a flat inclined surface that is continuous with the end of the contact surface on the bending machine side and is inclined relative to the contact surface so as to form an acute angle with the contact surface; A folding device comprising:

2. The folding device according to claim 1, The folding machine is a bending mold configured to be rotatable around a rotation axis extending in a direction perpendicular to a surface on which the outer mold and the inner mold are placed; A folding device comprising:

3. The folding device according to claim 1, further comprising: a pressing die arranged to be stacked on the outer die and the inner die; A bending device comprising:

4. The folding device according to claim 1, The inner mold further comprises: a padding portion formed on the inclined surface; Including, The padding portion is a support surface provided on the folding machine side of the contact surface and non-parallel to the contact surface, for supporting the web when the material is folded; A folding device comprising:

5. A method for manufacturing a structural member, comprising: a preparation step of preparing a blank including a web and a flange continuous with a side edge of the web; a preforming step of forming a preformed portion on the flange that is recessed inward from the material; a folding step of folding the material by the folding device according to any one of claims 1 to 4 after the preforming step; Equipped with The preforming section is a first ridge portion at the bottom of the preformed portion, the first ridge portion extending from the side edge of the web toward an end of the flange opposite the web; a second ridge portion at each of both edge portions of the preformed portion, the second ridge portion extending from the web-side end of the first ridge portion toward the end of the flange so as to become more spaced from the first ridge portion as the second ridge portion approaches the end of the flange; Including, The bending step includes: a step of sandwiching the web between the outer mold and the inner mold on one side of the first ridge line portion; a step of folding the material while folding the preformed portion into the inside of the material along the first ridge line portion and the second ridge line portion by pushing the web from the outer mold side toward the inner mold side by the folding machine on the other side of the first ridge line portion; A manufacturing method comprising:

6. A structural member, The web and a flange continuous with the side edge of the web; A plurality of folds; Equipped with A structural member, wherein at each of the bent portions, a portion of the flange is folded inward of the structural member, thereby causing the structural member to be in a bent state.

7. A structural member, The web and a flange continuous with the side edge of the web; a bent portion in the structural member, which is a portion where a part of the flange is bent by folding inward; Equipped with A structural member in which the depth of the depression occurring in the bent portion is 1.0 mm or less, based on a straight line tangent to both ends of the web in the width direction at the bent portion, when the structural member is viewed along a direction perpendicular to the web.

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