JP6634043B2 - Method for manufacturing L-shaped square tube, apparatus for manufacturing L-shaped square tube, and L-shaped square tube - Google Patents

Description

  The present 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.

  2. Description of the Related Art Conventionally, L-shaped square steel pipes have been used as a structural member forming a frame of a frame for a unit bus or a structural member used for a partition wall for attaching an outer wall panel for a prefabricated house to a beam or the like.

  As a method of manufacturing an L-shaped square steel pipe, a method is used in which one end of two square steel pipes is welded while being pressed against a side surface of the other end to fix the square steel pipe.

  However, in this method, it is necessary to weld the entire end of the square steel pipe in order to obtain a sufficient joining strength. If the cutting accuracy or positioning accuracy of the end of the square steel pipe is low, the required strength may not be obtained even by welding. When welding, dimensional accuracy may be reduced due to the occurrence of warpage or twisting due to thermal strain. There is also a problem in that the working environment deteriorates due to fumes generated in welding. The welded portion needs to be finished or repaired in consideration of the appearance specifications and corrosion resistance.

  In addition, a technique has been proposed in which a V-shaped notch is formed in the upper surface and both side surfaces of a square steel pipe and bent, and then the abutting both side surfaces are welded (see Patent Document 1).

JP 2010-201503 A

However, according to the above-mentioned conventional technology, a V-shaped notch is formed on the upper surface and both side surfaces of the square steel pipe, and therefore, of the four surfaces of the square steel pipe, only one of the bottom surfaces is not cut. For this reason, the notch portion of the square steel pipe has significantly reduced strength as compared with other portions. In order to compensate for the decrease in strength, it is necessary to weld a portion where the notch is abutted.
Then, as described above, dimensional accuracy may be reduced due to occurrence of warpage or torsion due to thermal strain. Further, there is also a problem that the working environment is deteriorated due to fumes generated in welding.
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 that ensure sufficient strength without performing welding.

  The present invention provides a groove portion forming step of forming a groove portion by pressing one surface of a square tube along the short direction of the one surface to the other surface located on the back side of the one surface, and A bending step of bending the rectangular tube so that both sides sandwiching the groove are close to each other.

  In the groove forming step, it is preferable that the groove is formed by pressing a corner of the V-shaped portion of the pressing member having the V-shaped portion against the one surface.

  It is preferable that the angle of the corner of the V-shaped portion corresponds to the bending angle of the square tube.

  Prior to the groove forming step, a buckling line is formed by pressing two side surfaces between the one surface and the other surface of the square tube inward along a longitudinal direction of the side surfaces to form a buckling line. Preferably, a step is included.

  The present invention provides a groove forming apparatus for forming a groove by pressing one surface of a square tube along the short direction of the one surface to the other surface located on the back side of the one surface, and A bending device for bending the rectangular tube so that both sides sandwiching the groove are close to each other.

  The present invention is an L-shaped square tube in which the square tube is bent with a groove provided along the short side of one surface thereof.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the L-shaped square tube which ensured sufficient intensity | strength without performing welding, the manufacturing apparatus of an L-shaped square tube, and an L-shaped square tube can be provided.

It is a figure explaining the manufacturing method of the L-shaped square steel pipe which bends a square steel pipe and manufactures an L-shaped square steel pipe. It is the schematic of the buckling line formation apparatus which implement | achieves a buckling line formation process. It is the schematic of the groove part formation apparatus which implement | achieves a groove part formation process. It is a bending apparatus schematic diagram which implement | achieves a bending process. It is a photograph of the square steel pipe in the state where the groove was formed by the groove part formation process of the manufacturing method of this embodiment. It is a photograph of the bent part of the L-shaped square steel pipe after bending by the bending process of the manufacturing method of this embodiment. It is the figure which showed the application example of the bending method of the square steel pipe of this embodiment, (a) is the figure which showed the square steel pipe which has two bent parts, and (b) is the square steel pipe which has three bent parts. is there.

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

  In the method of manufacturing the L-shaped square steel tube 1A, one surface 1a of the square steel tube 1 extending linearly as shown in FIG. 1A is positioned on the back side of the one surface 1a along the short direction of the one surface 1a. By pressing against the other surface 1b side, a groove 5 is formed as shown in FIG. 1 (c), and then the square steel pipe 1 is bent to form an L-shape having a bent portion A as shown in FIG. 1 (d). This is a method for manufacturing the square steel pipe 1A.

  In the present embodiment, the square steel pipe 1 bent into an L shape is a hollow square pipe made of steel having a rectangular cross section. However, the present embodiment is not limited to steel, and may be another material as long as the material can be plastically deformed by bending.

  In this embodiment, the case where the cross section of the square steel pipe 1 is rectangular will be described, but may be square. However, it is preferable that the cross section of the square steel pipe 1 is rectangular, and that the width of the first surface 1a and the other surface 1b in the short direction is larger than the width of the side surfaces 1c and 1d in the short direction.

  Further, in the following description, a method of manufacturing the L-shaped square steel pipe 1A having the bent portion A bent at a right angle (90 °) will be described. However, the bent angle of the bent portion A is not limited to a right angle, but is an acute angle. However, the angle may be obtuse.

  As shown in FIG. 1, the method of manufacturing the L-shaped square steel pipe 1 </ b> A according to the present embodiment includes a buckling line in which the side surfaces 1 c and 1 d of the square steel pipe 1 shown in FIG. A forming step (FIG. 1B), a groove forming step of pressing the one surface 1a of the square steel pipe 1 to form the groove 5 (FIG. 1C), and a bending step of bending the square steel pipe 1 (FIG. 1D) )).

  The method for manufacturing the L-shaped square steel pipe 1A is performed by an L-shaped square pipe manufacturing apparatus 100 including a buckling line forming device 2, a groove forming device 3, and a bending device 15 described below. However, the method for manufacturing the L-shaped square steel pipe 1A of the present embodiment is not limited to using the manufacturing apparatus 100.

(Buckling line forming process)
The buckling line forming step is a step of pressing the side surfaces 1c and 1d of the square steel pipe 1 to form the buckling lines 4 on the side surfaces 1c and 1d, as shown in FIG.

FIG. 2 shows an example of a specific buckling line forming apparatus 2 for realizing the buckling line forming step. However, the device for forming the buckling lines 4 on the side surfaces 1c and 1d of the square steel pipe 1 is not limited to the buckling line forming device 2.
The buckling line forming device 2 includes two side pressing punches 6 each having a V-shaped portion 6a provided on one side surface of a rectangular parallelepiped. The two side pressing punches 6 are arranged so that the corner 6b of the V-shaped portion 6a extends along the longitudinal direction of the side surfaces 1c and 1d. Further, the corner portion 6b of the V-shaped portion 6a is disposed so as to sandwich the square steel pipe 1 from the side surfaces 1c and 1d in a state where the corner portion 6b can contact the substantially central portion of the side surfaces 1c and 1d.

The corners 6b of the V-shaped portions 6a of the two side pressing punches 6 are respectively brought into contact with the substantially central portions of the side surfaces 1c and 1d of the square steel pipe 1 along the longitudinal direction.
In a state where the square steel pipe 1 is sandwiched between the two side pressing punches 6, a force in a direction approaching each other is applied to the two side pressing punches 6 so that the centers of the side surfaces 1c and 1d of the square steel pipe 1 are depressed inward. It is deformed to form a buckling line 4 along the longitudinal direction.

The length of the buckling line 4 is appropriately adjusted in accordance with the dimensions of the square steel pipe 1 so that a portion provided with the buckling line 4 easily buckles inward in a groove forming step described later.
The deformation (depth) of the buckling line 4 is preferably as deep as possible without breaking the side surfaces 1c and 1d.
After forming the buckling line 4, the two side pressing punches 6 are separated from the side surfaces 1 c and 1 d of the square steel pipe 1.

(Groove forming step)
In the groove forming step, as shown in FIG. 1C, one surface 1 a of the square steel pipe 1 is pressed toward the other surface 1 b along the short direction of the one surface 1 a to form the V-shaped groove 5. This is the step of forming.

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

The side holding part 7 is a rectangular parallelepiped and holds the square steel pipe 1 by contacting the side faces 1c and 1d of the square steel pipe 1. In FIG. 3, one of the two side holding parts 7 overlapping with the square steel pipe 1 is indicated by a dotted line.
The groove forming punch 8 has a shape in which a V-shaped portion 8a is provided on one surface of a rectangular parallelepiped like the side surface pressing punch 6. The groove forming punch 8 is arranged above the surface 1a such that the corner 8b of the V-shaped portion 8a is positioned on the center line M of the surface 1a where the groove is to be formed.

  In the present embodiment, the angle θ of the V-shaped portion 8a is slightly larger than the bending angle of the L-shaped square steel pipe 1A (in the present embodiment, a right angle (90 °)). As described above, by making the angle θ of the V-shaped portion 8a slightly larger than the bending angle of the square steel pipe 1, when the square steel pipe 1 is bent in the next bending step, the bending angle of the L-shaped square steel pipe 1A is increased. This is a desired value (a right angle (90 °) in the present embodiment).

When forming the V-groove portion 5, it is preferable to add R to the corner portion 8 b of the V-shaped portion 8 a so as not to break the square steel pipe 1.
The pushing amount of the groove forming punch 8 is such that the pushing depth at this time is such that one surface 1a is in contact with the other surface 1b. Thereby, breakage of each surface of the square steel pipe 1 is prevented.

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

  In the present embodiment, an L-shaped square steel pipe 1A is manufactured by bending the square steel pipe 1 at a substantially right angle, but the present invention is not limited to this. The angle of the L portion of the L-shaped square steel pipe 1A can be adjusted, and the angle of the corner 8b of the groove forming punch 8 can also be adjusted according to the angle of the L-shape.

(Bending process)
As shown in FIG. 1D, the bending step is a step of bending the square steel pipe 1 such that both sides (one 1aa and the other 1ab) of the one surface 1a sandwiching the portion where the groove 5 is formed approach each other. .

FIG. 4 shows an example of a specific bending apparatus (fold bending die) 15 for realizing the bending step. However, the device for bending the square steel pipe 1 is not limited to this device.
The bending device 15 includes two holding plates 9, a top die 10, a bottom die 11, a bend die 12, and a bend punch 13.

  The holding plate 9 is a plate member that holds the side surfaces 1 c and 1 d of the square steel pipe 1. Two holding plates 9 are provided, hold the square steel pipe 1 between each other, press the side faces 1c and 1d, and hold the square steel pipe 1 so as not to move. 4, one holding plate 9 is indicated by a dotted line.

  The top die 10 has substantially the same width as the square steel pipe 1 and is arranged so as to press one side 1aa of the square steel pipe 1 on one side 1a of the surface 1a where the groove 5 is provided.

  The bottom die 11 has substantially the same width as the square steel pipe 1 and is disposed on the opposite side of the top die 10 with the square steel pipe 1 therebetween (on the side in contact with the other surface 1b of the square steel pipe 1).

The bend die 12 has substantially the same width as the square steel pipe 1, and is rotatable about the rotary shaft 14 with respect to the bottom die 11.
The bend die 12 is linearly aligned with the bottom die 11 in the state of FIG. 4A before the square steel pipe 1 is bent.
4B after the L-shaped square steel pipe 1A is manufactured, the bend die 12 is in a state of being inclined at substantially a right angle to the bottom die 11 about the rotation shaft 14.

  The bend punch 13 is a rectangular parallelepiped, and is connected to an advance / retreat mechanism (not shown). In the state shown in FIG. 4A before the square steel pipe 1 is bent, one surface perpendicular to the advance / retreat direction is in contact with the vent die 12.

When the bend punch 13 is moved toward the square steel pipe 1 by an advance / retreat mechanism (not shown), the bend die 12 is pushed up.
Then, the bend die 12 rotates about the rotation shaft 14.
By this rotation, the other surface of the other side 1ab sandwiching the groove 5 in the square steel pipe 1 is pushed up.
Thereby, the other 1ab of the square steel pipe 1 rotates, and the one surface 1a side of the other 1ab contacts the side surface of the top die 10. Further, a surface of the bend punch 13 parallel to the advance / retreat direction comes into contact with the bend die 12.
The bending angle of the L-shaped bent portion A of the L-shaped square steel pipe 1A can be adjusted by adjusting the amount by which the bend punch 13 is pushed up. For example, in the state of FIG. 4B, the L-shaped square steel pipe 1A is bent by 90 ° in a state of being pushed up to the maximum.

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

As described above, the L-shaped square steel pipe 1A manufactured according to the present embodiment is formed without notching the four side surfaces of the square steel pipe 1.
Therefore, the strength does not decrease, and since the laminated portion is hardened by bending, the strength is improved despite no welding.
Further, since there is no need to cut or weld the side surface, a high-strength L-shaped square steel pipe 1A can be manufactured at low cost.

  If higher rigidity is required, the bent portion or the folded side surfaces may be joined by welding or an adhesive.

As shown in FIG. 7A, the method of bending the square steel pipe 1 according to the present embodiment is such that a square steel pipe 1 having two bent portions B is further bent twice for one square steel pipe 1. 1B can be manufactured stably at low cost.
Further, as shown in FIG. 7 (b), by bending one square steel pipe 1 three times, a square steel pipe 1C having four bent portions C can be stably manufactured at low cost.
Therefore, according to the present embodiment, it is possible to provide a low-cost member for household appliances such as a housing of a high-strength household appliance or a face material of a pallet, or a frame for a frame for a unit bath.

Further, by using the L-shaped square pipe manufacturing apparatus 100 including the above-described buckling line forming apparatus 2, groove forming apparatus 3 and bending apparatus 15, bending of the square steel pipe 1 can be performed with high precision, smoothly and stably. It can be carried out.
However, the present invention is not limited to bending by the above-described bending device, and may be formed without using these devices (die).

DESCRIPTION OF SYMBOLS 1 Square steel pipe 1A L-shaped square steel pipe 1a One surface 1b Other surface 1c Side surface 1d Side surface 2 Buckling line forming device 3 Groove forming device 4 Buckling line 5 Groove portion 6 Side pressing punch 7 Side holding portion 8 Groove forming punch 15 Bending device 100 Manufacturing equipment A Folded part M Center line of planned groove part

Claims (4)

A buckling line forming device that presses two side surfaces of the square tube inward along the longitudinal direction to form a buckling line;
A groove forming apparatus that forms a groove by pressing one surface between the two side surfaces of the square tube along the short direction of the one surface toward the other surface located on the back side of the one surface,
In the one surface of the square tube, a top die arranged to press one surface sandwiching the groove, a bottom die arranged on the side opposite to the top die of the square tube, before the square tube is bent. In this state, the vent die is arranged in a straight line with the bottom die and is rotatable about a rotation axis with respect to the bottom die, abuts on the vent die, pushes up the vent die by moving to the square tube side, and lifts the vent die. A vent punch that rotates about a rotation axis, and two holding plates that hold the two side surfaces of the square tube, wherein the square tube is positioned so that both sides of the one surface sandwiching the groove are close to each other. A bending device for bending,
An apparatus for manufacturing an L-shaped square tube provided with: The vent punch, the amount of movement to the square tube side is adjustable,
The apparatus for manufacturing an L-shaped square tube according to claim 1 . The groove forming apparatus forms the groove by pressing a corner of the V-shaped part of the pressing member having the V-shaped part against the one surface,
L-shaped square tube manufacturing apparatus according to claim 1 or 2. The angle of the corner of the V-shaped portion corresponds to the bending angle of the square tube,
An apparatus for manufacturing an L-shaped square tube according to claim 3 .