TWI683709B - Manufacturing method of L-shaped square tube - Google Patents

Abstract

The problem to be solved by the present invention is to provide a method for manufacturing an L-shaped square tube, an apparatus for manufacturing an L-shaped square tube, and an L-shaped square tube. The method for manufacturing an L-shaped square tube can be ensured even without welding Enough strength.

In order to solve this problem, the present invention provides a method for manufacturing an L-shaped square tube 1A, including: a groove forming step, which is to place a side 1a of the square steel tube 1 along the short side direction of the side 1a toward the side of the side 1a The other surface 1b on the back side is pressed to thereby form the groove 5; and, in the bending step, the square tube is bent so that the two sides of the one surface 1a sandwiching the groove 5 are close to each other.

Description

Manufacturing method of L-shaped square tube

The invention relates to a method for manufacturing an L-shaped square tube, an apparatus for manufacturing an L-shaped square tube, and an L-shaped square tube.

In the past, structural members used to form the frame of the abutment for a unit bathroom, or structural members used for partition walls such as prefabricated residential outer wall panels mounted on beams and columns It is an L-shaped square steel pipe.

As a method of manufacturing an L-shaped square steel pipe, a method of fixing the square steel pipe by welding one end portion against the side surface of the other end portion is adopted for two square steel pipes.

However, in this method, in order to obtain sufficient joint strength, it is necessary to perform all-round welding on the end of the square steel pipe. If the cutting accuracy or positioning accuracy of the end portion of the square steel pipe is low, the required strength cannot be obtained even by welding. If welding is performed, warpage and distortion caused by thermal strain may reduce dimensional accuracy. Particulate contamination (fume) is generated during welding, so there is a problem of deterioration of the working environment. Furthermore, in consideration of the appearance and corrosion resistance of the welded part, fine processing or repairs must be performed.

In addition, a manufacturing technique has been proposed (refer to Patent Document 1), in which a V-shaped notch is formed on the top surface and both side surfaces of a square steel pipe and bent, and then the two contacted side surfaces are welded.

[Prior Art Literature] (Patent Literature) Patent Literature 1: Japanese Patent Laid-Open No. 2010-201503

[Problems to be Solved by the Invention] However, the above-mentioned prior art is to add V-shaped cuts to the top surface and both sides of the square steel pipe, so of the four sides of the square steel pipe, only one side of the bottom surface is not incision. Therefore, the strength of the cut portion of the square steel pipe is significantly reduced compared to other parts. In order to compensate for the decrease in strength, welding must be performed at the part where the cuts are in close contact with each other. In doing so, as described above, warpage and distortion caused by thermal strain may reduce the dimensional accuracy. In addition, particulate contaminants are generated during welding, so there is a problem that the working environment deteriorates. An object of the present invention is to provide an L-shaped square tube manufacturing method, an L-shaped square tube manufacturing apparatus, and an L-shaped square tube. The L-shaped square tube can ensure sufficient strength without welding.

[Technical Means for Solving the Problem] According to an embodiment of the present invention, it is a method for manufacturing an L-shaped square tube, which includes: a groove forming step which places one side of the square tube along the short side of the side The other side of the inner surface of the one surface is pressed to thereby form a groove; and, in the bending step, the square tube is bent so that both sides of the one surface sandwiching the groove are close to each other.

In the groove forming step, the groove is preferably formed by pressing the corner of the V-shaped portion of the pressing member having the V-shaped portion toward the one surface.

The angle of the corner of the V-shaped portion preferably corresponds to the bending angle of the square tube.

Before the groove forming step, it is preferable to include a buckling line forming step, which is to place the two side surfaces between the one surface and the other surface in the square tube along the long side direction of the side surface Push inside to form a flexion curve.

According to other embodiments of the present invention, it is an L-shaped square tube manufacturing device, including: a groove forming device that aligns one side of the square tube along the short side of the one side to the other located on the inner side of the previous side Pushing on one side, thereby forming a groove; and, a bending device that bends the square tube so that the two sides sandwiching the groove on the one side are close to each other.

The present invention is an L-shaped square tube which is bent so as to sandwich a groove provided along the short side direction of one surface of the square tube.

[Effects of the Invention] According to the present invention, it is possible to provide a method for manufacturing an L-shaped square tube, an apparatus for manufacturing an L-shaped square tube, and an L-shaped square tube, which can be secured even without welding Enough strength.

Hereinafter, a method of manufacturing the L-shaped square steel pipe 1A according to an embodiment of the present invention will be described. FIGS. 1(a) to 1(d) are explanatory diagrams of the manufacturing method of the L-shaped square steel pipe 1A of the present embodiment.

The manufacturing method of the L-shaped square steel pipe 1A is to extend one side 1a of the linear square steel pipe 1 as shown in FIG. 1(a), along the short side direction of the one side 1a, to the other located on the back of the one side 1a Push on the 1b side. With this, the groove portion 5 as shown in FIG. 1(c) is formed. Next, the square steel pipe 1 is bent to manufacture an L-shaped square steel pipe 1A having a bent portion A as shown in FIG. 1(d).

The L-shaped square steel pipe 1 bent in this embodiment is a steel hollow square pipe with a rectangular cross section. However, this embodiment is not limited to steel, and may be other materials as long as it can be plastically deformed by bending.

In the present embodiment, the case where the cross section of the square steel pipe 1 is rectangular will be described, but the cross section may be square. However, if the cross section of the square steel pipe 1 is rectangular, the width of the one side 1a and the other side 1b in the short-side direction is preferably larger than the width of the side 1c and the side 1d in the short-side direction.

In the following description, a method for manufacturing an L-shaped square steel pipe 1A having a bent portion A bent at a right angle (90∘) will be described. However, the angle at which the bent portion A is bent is not limited to a right angle, and may be an acute angle or an obtuse angle.

As shown in FIG. 1, the manufacturing method of the L-shaped square steel pipe 1A of the present embodiment includes pressing the side surface 1c and the side surface 1d of the square steel pipe 1 shown in FIG. 1(a) to set the yield curve 4 Step of forming a buckling curve (Fig. 1(b)); a step of forming a groove portion by pushing a side 1a of the square steel pipe 1 to form a groove portion 5 (Fig. 1(c)); and bending the square steel pipe 1 Step (Figure 1(d)).

The manufacturing method of the L-shaped square steel pipe 1A is implemented by an apparatus 100 for manufacturing an L-shaped square tube. The manufacturing apparatus 100 for an L-shaped square tube includes a buckling curve forming device 2 and a groove forming device 3 to be described later. 、弯装置15。 Bending device 15. However, the manufacturing method of the L-shaped square steel pipe 1A of this embodiment is not limited to the use of this manufacturing apparatus 100.

(Bending curve forming step) As shown in FIG. 1(b), the bending curve forming step is a step of pressing the side surface 1c and the side surface 1d of the square steel pipe 1 to form the buckling curve 4 on the side surface 1c and the side surface 1d.

FIG. 2 shows an example of a specific bending curve forming device 2 for realizing the bending curve forming step. However, the device for forming the yield curve 4 on the side surface 1c and the side surface 1d of the square steel pipe 1 is not limited to this yield curve forming device 2. The buckling curve forming device 2 includes two side pressing punches 6 having a V-shaped portion 6a on one side of a rectangular parallelepiped. The two side-surface pressing punches 6 are arranged at the corners 6b of the V-shaped portion 6a along the longitudinal direction of the side surface 1c and the side surface 1d. Further, the corner portion 6b of the V-shaped portion 6a is arranged so as to sandwich the square steel pipe 1 from the side surface 1c and the side surface 1d side in a state where it can abut approximately the center of the side surface 1c and the side surface 1d.

The corner portions 6b of the V-shaped portion 6a of the two side pressing punches 6 each contact the side surface 1c and the side surface 1d of the square steel pipe 1 along the longitudinal direction and at approximately the center. In a state where the square side steel pipe 1 is clamped by the two side pressing punches 6, forces are applied to the two side pressing punches 6 in the direction close to each other, so that the center of the side surface 1c and the side surface 1d of the square steel tube 1 It is recessed and deformed to form a flexion curve 4 along the longitudinal direction.

The length of the buckling curve 4 can be appropriately adjusted in accordance with the size of the square steel pipe 1 so that the portion where the buckling curve 4 is provided in the groove forming step to be described later easily buckles to the inside. In addition, the amount of deformation (depth) of the yield curve 4 is preferably within a range that does not break the side surface 1c and the side surface 1d. Furthermore, after the yield curve 4 is formed, the two side pressing punches 6 are separated from the side surface 1c and the side surface 1d of the square steel pipe 1.

(Groove formation step) As shown in FIG. 1(c), the groove formation step is to press one surface 1a of the square steel pipe 1 along the short side direction of the surface 1a toward the other surface 1b to form a V-shape Steps in the shape of the groove 5.

FIG. 3 shows an example of a specific groove forming device 3 (extrusion die) for performing a groove forming step. The groove forming device 3 includes two side holding portions 7 and a groove forming punch 8. However, the device for pressing the one surface 1 a of the square steel pipe 1 to form a V-shaped groove 5 in the square steel pipe 1 is not limited to this.

The side holding portion 7 is a rectangular parallelepiped, and abuts the side face 1c and the side face 1d of the square steel pipe 1 to hold the square steel pipe 1. In addition, in the third drawing, the one overlapping the square steel pipe 1 among the two side holding portions 7 is indicated by a broken line. The groove portion forming the punch 8 is formed in a shape of a V-shaped portion 8a formed on one surface of a rectangular parallelepiped, similar to the side pressing punch 6. Furthermore, the groove portion forms the punch 8, and the corner portion 8b of the V-shaped portion 8a is arranged above the one surface 1a so as to be positioned on the center line M where the groove portion of the one surface 1a is to be formed.

In the present embodiment, the angle θ of the V-shaped portion 8a is only slightly larger than the bending angle of the L-shaped square steel pipe 1A (in this embodiment, the right angle (90∘)). In this way, the angle θ of the V-shaped portion 8a is only slightly larger than the bending angle of the square steel pipe 1, whereby when the square steel pipe 1 is bent in the next bending step, the L-shaped square steel pipe 1A can be bent The angle becomes the desired value (in this embodiment, it is a right angle (90∘)).

In addition, the angle θ of the V-shaped portion 8a is preferably such that when the V-shaped groove portion 5 is formed, the R value is assigned so that the square steel pipe 1 does not break. The groove portion forms the pushing amount of the punch 8, and the pushing depth at this time is such that one surface 1a contacts the other surface 1b. Thereby, the fracture of each surface of the square steel pipe 1 is prevented.

First, the square steel pipe 1 is arranged between the two side holding portions 7. Then, the corner portion 8b of the V-shaped portion 8a of the groove portion forming punch 8 is brought into contact with the center line M. Next, a force is applied to the groove forming punch 8 to form the groove 5 of the square steel pipe 1 at a predetermined position, and is pressed into the other surface 1b side. The pressing depth at this time is the degree that one surface 1a contacts the other surface 1b. As a result, as shown in FIG. 3, one surface 1a of the square steel pipe 1 is crushed and deformed to form a V-shaped groove 5. Then, after the groove portion 5 is formed, the groove portion forming punch 8 is separated from the one surface 1 a of the square steel pipe 1.

In addition, in the present embodiment, the square steel pipe 1 is bent at a substantially right angle to produce an L-shaped square steel pipe 1A, but it is not limited thereto. The angle (bending angle) of the L portion of the L-shaped square steel pipe 1A may be adjusted, and the angle of the corner portion 8b of the groove forming punch 8 may be adjusted in accordance with the L-shaped angle.

(Bending step) As shown in FIG. 1(d), the bending step is such that both sides (one 1aa and the other 1ab) of the portion on one surface 1a sandwiching the groove 5 are close to each other, Steps to bend the square steel tube 1. .

FIG. 4 shows an example of a specific bending device 15 (folding and bending mold) that performs a bending step. However, the bending device of the square steel pipe 1 is not limited to this device. The bending device 15 includes two pressing plates 9, a top die 10, a bottom die 11, a bending die 12, and a bending punch 13.

The pressing plate 9 is a plate member that presses the side surface 1c and the side surface 1d of the square steel pipe 1. The pressing plate 9 is provided with two pieces, sandwiching the square steel pipes 1 between each other and pressing the side faces 1c and the side faces 1d to keep the square steel pipes 1 from moving. The one pressing plate 9 in FIG. 4 is indicated by a broken line.

The top mold 10 has approximately the same width as the square steel pipe 1 and is arranged to be pressed against the side 1 a of the side 1 a of the square steel pipe 1 sandwiching the portion where the groove 5 is provided.

The bottom mold 11 has approximately the same width as the square steel pipe 1 and is disposed on the opposite side of the top mold 10 (contact side with the other surface 1b of the square steel pipe 1) so as to sandwich the square steel pipe 1.

The bending die 12 has a width that is approximately the same as that of the square steel pipe 1 and can be rotated with the rotating shaft 14 as a center with respect to the bottom die 11. The bending die 12 is arranged in line with the bottom die 11 in the state of FIG. 4(a) before the square steel pipe 1 is bent. In the state of FIG. 4(b) after the square steel pipe 1 is bent, the bending die 12 is inclined at a substantially right angle with respect to the bottom die 11 with the rotating shaft 14 as the center.

The bending punch 13 is a rectangular parallelepiped, and is connected to an advancing and retracting mechanism (not shown). In the state of FIG. 4( a) before the square steel pipe 1 is bent, the side of the bending punch 13 perpendicular to the advancing and retracting direction abuts against the bending die 12.

When the bending punch 13 moves to the side of the square steel pipe 1 by an advance and retreat mechanism (not shown), the bending die 12 is pushed up. In this way, the mold 12 is bent to rotate around the rotating shaft 14. By the rotation, the other surface 1ab of the portion of the square steel pipe 1 sandwiching the groove 5 is pushed up. As a result, the other side 1ab of the square steel pipe 1 rotates, and the side 1a side of the other side 1ab abuts to the side surface of the top mold 10. In addition, the surface of the bending punch 13 parallel to the advancing and retracting directions abuts the bending die 12. In addition, by adjusting the amount by which the bending punch 13 is pushed up, the bending angle of the L-shaped bending portion A of the L-shaped square steel pipe 1A can be adjusted. For example, the state in Fig. 4(b) is the maximum state of pushing up, so that the L-shaped square steel pipe 1A is bent to 90∘.

FIG. 5 is a photograph of a square steel pipe in a state where the groove 5 is formed by the groove forming step of the manufacturing method of this embodiment. FIG. 6 is a photograph of the bent portion A of the L-shaped square steel pipe 1A bent by the bending step of the manufacturing method of the present embodiment.

In this way, the L-shaped square steel pipe 1A manufactured by the present embodiment is formed so that none of the four side surfaces of the square steel pipe 1 has cutouts. Therefore, there is no decrease in strength, and furthermore, because the layered portion is hardened by bending, the strength is slightly improved even if there is no welding. In addition, since it is not necessary to cut or weld the side surface, it is possible to manufacture a high-strength L-shaped square steel pipe 1A at a low cost.

In addition, when higher rigidity is required, fusion bonding or bonding with an adhesive may be performed on the bent portion or the folded-in side surfaces.

As shown in FIG. 7(a), the method of bending the square steel pipe 1 of the present embodiment is further performed by bending the square steel pipe 1 twice, whereby the two bends can be stably manufactured at low cost The square steel pipe 1B of the portion B, as shown in FIG. 7(b), is subjected to three bendings for one square steel pipe 1, whereby a quadrilateral with four bent portions C can be stably manufactured at low cost Square steel pipe 1C. Therefore, according to the present embodiment, it is possible to provide a high-strength home appliance housing such as a housing of a home appliance, a face plate of a pallet, or a housing of a base frame for a bathroom, etc. at low cost Associated components.

In addition, by using the manufacturing apparatus 100 of the L-shaped square tube, the square steel pipe 1 can be bent with high precision, smoothly, and stably. The manufacturing apparatus 100 of the L-shaped square tube includes: The device 2, the groove forming device 3, and the bending device 15. However, the present invention is not limited to the bending caused by the above-mentioned bending device, and may be formed without using these devices (die).

1‧‧‧Square steel pipe 1A‧‧‧L-shaped square steel pipe 1B‧‧‧Square steel pipe with 2 bends 1C‧‧‧Square steel pipe with 4 bends C 1a‧‧‧Square steel pipe The side 1aa‧‧‧ One side on one side of the square steel pipe 1ab‧‧‧ The other side on the one side of the square steel pipe 1b‧‧‧The other side 1c, 1d‧‧‧The side of the square steel pipe 2‧‧‧ Buckling curve forming device 3‧‧‧Groove forming device 4‧‧‧Bending curve 5‧‧‧Groove part 6‧‧‧Side pushing punch 6a‧‧‧Side pushing V-shaped part 6b Press the corner of the punch 7‧‧‧Side holding part 8‧‧‧The groove forms the punch 8a‧‧‧The groove forms the V-shaped part of the punch 8b‧‧‧The groove forms the corner of the punch 9‧‧‧ Plate 10‧‧‧Top mold 11‧‧‧Bottom mold 12‧‧‧Bending mold 13‧‧‧Bending punch 14‧‧‧Rotating shaft 15‧‧‧Bending device 100‧‧‧L-shaped square tube manufacturing Device A, B, C ‧‧‧ Bending part M‧‧‧ Groove forms the central line θ‧‧‧‧V angle

FIG. 1 is an explanatory diagram of a method for manufacturing an L-shaped square steel pipe, which bends the square steel pipe to produce an L-shaped square steel pipe. Fig. 2 is a schematic diagram of a flexion curve forming device for realizing a flexion curve forming step. Fig. 3 is a schematic diagram of a groove forming device for realizing a groove forming step. Fig. 4 is a schematic diagram of a bending device for realizing a bending step. FIG. 5 is a photograph of a square steel pipe in a state where a groove is formed by the groove forming step of the manufacturing method of this embodiment. FIG. 6 is a photograph of the bent portion of the L-shaped square steel pipe bent by the bending step of the manufacturing method of this embodiment. FIG. 7 is a diagram showing an application example of a method for bending a square steel pipe according to the present embodiment. FIG. 7(a) is a diagram showing a square steel pipe having two bent portions, and FIG. 7(b) is a diagram showing Picture of a square steel pipe with three corners in a quadrangle.

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(Please specify separately on page change)

1‧‧‧Square steel pipe

1A‧‧‧L-shaped square steel pipe

1a‧‧‧One side of square steel pipe

1aa‧‧‧one side of the square steel pipe

1ab‧‧‧ on the other side of the square steel pipe

1b‧‧‧The other side of the square steel pipe

1c, 1d‧‧‧Side of square steel pipe

4‧‧‧flexion curve

5‧‧‧ Ditch

M‧‧‧Central Line

Claims (3)

A method for manufacturing an L-shaped square tube, comprising: a groove forming step, which pushes one side of the square tube along the short side direction of the one side toward the other side located on the back side of the aforementioned one, thereby forming a groove A buckling curve forming step, which is performed before the groove forming step, the buckling curve forming step pushes the two side surfaces between the one side and the other side of the square tube inward along the long side direction of the side surface Press to form a flexion curve; and, in the bending step, the top mold is used to press the side of the square tube sandwiching the groove, and the bottom mold is used to press the side of the square tube opposite to the top mold Surface, use two pressing plates to press the two sides of the square tube, and use a bending punch to move and rotate the bending die in the direction of travel, the bending die, before the square tube is bent In this state, the bottom mold is aligned linearly and can be rotated relative to the bottom mold, whereby the other side of the square tube sandwiching the groove is rotated to bend the square tube. The method for manufacturing an L-shaped square tube according to claim 1, wherein in the groove forming step, the groove is formed by pressing the corner of the V-shaped portion in the pressing member having the V-shaped portion to Push on the previous side While forming. The method for manufacturing an L-shaped square tube according to claim 2, wherein the angle of the corner of the V-shaped portion corresponds to the bending angle of the square tube.

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