JP2017221956A - Elbow pipe manufacturing method and rectangular metal pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elbow pipe manufacturing method and a rectangular metal pipe which enable the manufacture of an elbow pipe having an elbow shape curved in a desired shape.SOLUTION: An elbow pipe manufacturing method, by which is manufactured an elbow pipe having an elbow shape from a linear rectangular metal pipe, including the formation of a rectangular opening in a first plane of a processing region processed in the elbow shape in the rectangular metal pipe, the formation of a first V-shaped cut spread toward the first plane each in a second plane and a third plane that do not face the first plane, and the rectangular metal pipe is curved so that the opening is positioned inside the elbow shape to weld the processing region.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an elbow tube manufacturing method and a rectangular metal tube.

  Conventionally, when manufacturing an elbow pipe having a curved elbow shape, one end of a straight metal pipe as a material is fixed to the other end of the metal pipe using an apparatus such as a bender. In general, bending is performed by bending a part of the metal tube by applying a large force. For example, Patent Document 1 below discloses a method of bending using a bender while performing a heat treatment on a straight rectangular metal tube as a material.

JP-A-6-182453

  When the bending process as described above is performed on a rectangular metal tube, a cross section in which the metal tube is partially crushed in an elbow shape portion (curved bent portion of the elbow tube) of the elbow tube after manufacture Changes, wrinkles, creases, etc. are likely to occur on the surface of the metal tube. Therefore, it is difficult to obtain an elbow tube having an elbow shape curved to a desired shape while maintaining a smooth surface using the above-described method.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is a new and improved elbow tube having an elbow shape curved into a desired shape. Another object of the present invention is to provide an elbow pipe manufacturing method and a square metal pipe.

  In order to solve the above-described problems, according to an aspect of the present invention, there is provided a manufacturing method for manufacturing an elbow pipe having an elbow shape from a linear square metal tube, wherein the elbow shape is formed in the square metal tube. A rectangular opening is formed on the first surface of the processing region to be processed, and the first surface is formed on the second surface and the third surface of the processing region that are not opposed to the first surface. Forming a V-shaped first notch extending toward the surface of the metal plate, bending the square metal tube so that the opening is located inside the elbow shape, and welding the processing region. An elbow tube manufacturing method is provided.

  Each of the first cutouts in the second surface and the third surface is from a first side where the vertex of the V-shape contacts the first surface in the second surface and the third surface. A predetermined distance is formed, and the predetermined distance is shorter than a length of a second side that does not oppose the first side in the second surface and the third surface of the processing region. Also good.

  The predetermined distance may be two thirds or more of the length of the second side.

  After the formation of the first notch, the elbow pipe manufacturing method passes through the second surface and the third surface through the position of the V-shaped apex of the first notch and the processing region. Forming a cut line extending from one end portion to the other end portion, and cutting out a region sandwiched between a part of the side and the cut line for each of the two sides in the first cutout , Two fan-shaped portions having a radius of the predetermined distance are formed, and the second surface and the third surface on which the two fan-shaped portions are formed include a plurality of second portions along the cut line. The method may further include forming a notch.

  The plurality of second cutouts are formed such that the sum of the arc lengths of the two sector portions is equal to the length excluding the plurality of second cutouts formed from the cut lines. May be.

  Each of the second cutouts may have a V shape that extends toward the first surface.

  An angle of the V-shaped apex of each of the second cutouts may be 20 ° or less.

  Each of the second cutouts may have a trapezoidal shape extending toward the first surface.

  In order to solve the above-mentioned problem, according to another aspect of the present invention, a rectangular rectangular metal tube, which is a rectangular opening provided on the first surface of the rectangular metal tube. And a V-shaped first portion that is provided on each of the second surface and the third surface of the rectangular metal tube that are not opposed to the first surface and that extends toward the first surface. A square metal tube comprising a notch is provided.

  As described above, according to the present invention, it is possible to manufacture an elbow pipe having an elbow shape curved into a desired shape.

It is explanatory drawing for demonstrating the elbow pipe | tube 90 which concerns on this embodiment. It is explanatory drawing for demonstrating the flow of the manufacturing method of the elbow pipe | tube 90 which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the metal pipe 10 which concerns on this embodiment. It is explanatory drawing (the 1) for demonstrating the process in the manufacturing method of the elbow pipe | tube 90 which concerns on this embodiment. It is explanatory drawing (the 2) for demonstrating the process in the manufacturing method of the elbow pipe | tube 90 which concerns on this embodiment. It is explanatory drawing (the 3) for demonstrating the process in the manufacturing method of the elbow pipe | tube 90 which concerns on this embodiment. It is explanatory drawing (the 4) for demonstrating the process in the manufacturing method of the elbow pipe | tube 90 which concerns on this embodiment. It is explanatory drawing (the 5) for demonstrating the process in the manufacturing method of the elbow pipe | tube 90 which concerns on this embodiment. It is explanatory drawing (the 6) for demonstrating the process in the manufacturing method of the elbow pipe | tube 90 which concerns on this embodiment. It is explanatory drawing for demonstrating the process in the manufacturing method of the elbow pipe | tube 90 which concerns on the modification 2 of this embodiment. It is the enlarged view to which the area | region F in FIG. 10 was expanded. It is explanatory drawing for demonstrating the metal pipe 20 which concerns on this embodiment. It is explanatory drawing for demonstrating the metal pipe 60 which concerns on this embodiment.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the following description, specific numerical values for the length and angle are shown, but these numerical values are merely examples in the embodiments of the present invention, and the embodiments of the present invention are limited to these numerical values. Is not to be done. Furthermore, the specific numerical values for the length and angle in the following description do not mean only when the numerical values coincide with these numerical values. It also means that numerical values that have an industrially acceptable difference in elbow pipes are included. In addition, the description of the specific shape in the following description does not mean that it is geometrically this shape, but is industrially acceptable in the elbow pipe manufacturing process and the elbow pipe as a product. It means that shapes similar to the shape having different degrees are also included.

  Below, the manufacturing method of the elbow pipe | tube 90 which concerns on embodiment of this invention is demonstrated with reference to FIGS. FIG. 1 is an explanatory diagram for explaining an elbow pipe 90 according to the present embodiment. Specifically, the upper surface of the elbow pipe 90 manufactured by the manufacturing method according to the present embodiment as viewed from the upper surface 23 side. FIG. FIG. 2 is an explanatory diagram for explaining the flow of the manufacturing method of the elbow pipe 90 according to the present embodiment. FIG. 3 is an explanatory diagram for explaining the metal tube 10 according to the present embodiment, and in detail, is a perspective view of the metal tube 10 as a material in the manufacturing method according to the present embodiment. Further, FIG. 4 to FIG. 9 are explanatory diagrams for explaining each step in the method of manufacturing the elbow pipe 90 according to the present embodiment. Specifically, FIG. 4 is a side view of the metal tube 10 viewed from the inner side surface 21 side in one step of the manufacturing method. FIGS. 5 to 9 are top views of the metal tube 10 as viewed from the upper surface 23 side in each step of the manufacturing method.

  The embodiment of the present invention described below is applied to a method of manufacturing an elbow tube 90 for manufacturing an elbow tube 90 (see FIG. 1) having a curved elbow shape portion (elbow shape) 92. However, the present embodiment is not limited to being applied to the method for manufacturing the elbow tube 90 described above, and may be applied to, for example, a method for manufacturing a curved solid prism.

<Elbow tube 90>
First, an elbow pipe 90 manufactured by the manufacturing method according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, an elbow pipe 90 manufactured by the manufacturing method according to the present embodiment has a curved elbow shape portion 92. According to the manufacturing method of the present embodiment, it is possible to obtain an elbow-shaped portion 92 that curves into a desired shape while maintaining a smooth surface. Moreover, in the example shown by FIG. 1, the bending angle B of the elbow shape part 92 is 90 degrees. In the present embodiment, the bending angle B of the elbow-shaped portion 92 is not particularly limited as long as it is larger than 0 ° and smaller than 180 °, but the bending angle B may be around 90 °. preferable.

  In the following description, of the four surfaces of the elbow tube 90, the side surface that is the inside of the curvature of the elbow-shaped portion 92 of the elbow tube 90 is referred to as an inner surface (first surface) 21. A side surface facing the inner surface 21 is referred to as an outer surface 22, and a surface not facing the inner surface 21 is referred to as an upper surface (second surface) 23 and a lower surface (third surface) 24. Note that the upper surface 23 and the lower surface 24 face each other. Similarly, four surfaces of the metal tube 10 to be described later are also referred to as an inner surface 21, an outer surface 22, an upper surface 23, and a lower surface 24.

<Flow of manufacturing method>
Next, the flow of the manufacturing method of the elbow pipe 90 according to the embodiment will be described with reference to FIG. The manufacturing method according to the present embodiment uses a straight metal tube 10 (see FIG. 3) as a raw material, and by processing the metal tube 10, an elbow tube 90 having a curved elbow shape portion 92 (see FIG. 1). Manufacturing. As shown in FIG. 2, the manufacturing method includes a preparation step (S110) for preparing the straight metal tube 10 and a processing step for forming the opening 30 and the notches 32 and 38 in the metal tube 10 ( S120), a bending step (S130) for bending the processed metal tube 10, and a welding step (S140) for welding the bent metal tube 10 are sequentially included. Below, the detail of each process is demonstrated.

(Preparation step S110)
First, a preparation step S110 for preparing the metal tube 10 as a material is performed. Below, the metal pipe 10 used as a raw material prepared in preparation process S110 is demonstrated with reference to FIG. The said metal pipe 10 is a metal pipe formed from metal materials, such as aluminum, copper, iron, stainless steel, for example. As shown in FIG. 3, the metal tube 10 has a linear shape, a cross section having a rectangular shape, and four corners of the rectangle are rounded. In the present embodiment, the metal tube 10 as a raw material may be a square (square diameter) metal tube having a rectangular cross section as described above, and the four corners of the rectangular cross section are particularly rounded. It does not have to be tinged.

  In the present embodiment, the thickness of the metal tube 10 is not particularly limited, but is preferably 3 mm to 6 mm from the viewpoint of ease of processing. Further, in the present embodiment, the outer diameter of the metal tube 10 (the size of the gap between the inner surface 21 and the outer surface 22 of the metal tube 10) is not particularly limited, but easy to process. From the viewpoint of properties, it is preferably 20 mm to 100 mm. The length of the metal tube 10 can be arbitrarily selected according to the desired length of the elbow tube 90.

  In the following description, a region corresponding to the curved elbow shape portion 92 of the elbow tube 90 in the metal tube 10, that is, a processing region processed into an elbow shape is referred to as a processing region 12. Furthermore, in the length direction of the metal tube 10, positions corresponding to the ends of the processing region 12 are referred to as an end portion 14 a and an end portion 14 b. Further, as described above, of the four surfaces of the metal tube 10, the side surface that is the inner side of the curvature of the elbow-shaped portion 92 (see FIG. 3) of the elbow tube 90 is the inner surface 21 (first surface). The side surface facing the inner side surface 21 is referred to as an outer surface 22, and the surface not facing the inner side surface 21 is referred to as an upper surface (second surface) 23 and a lower surface (third surface) 24.

(Processing step S120)
Next, a processing step S120 for processing the metal tube 10 prepared in the preparation step S110 is performed. In the processing step S120, the processing region 12 of the metal tube 10 prepared in the preparation step S110 is processed using a laser cutter or the like. Details of the processing step S120 will be described below with reference to FIGS. However, in the following description, processing on the upper surface 23 is described with reference to FIGS. 5 to 8 which are top views of the metal tube 10 viewed from the upper surface 23 side, but in the present embodiment, on the lower surface 24. Also, the same processing as that of the upper surface 23 is performed.

  First, as shown in FIG. 4, a rectangular opening 30 is formed on the inner surface 21 of the processing region 12 of the metal tube 10. The opening 30 is formed as an opening that extends over the entire inner surface 21 of the processing region 12. Specifically, the opening 30 includes an end portion 14a of the processing region 12, an end portion 14b, a side 41 in contact with the upper surface 23 on the inner surface 21, and a lower surface 24 on the inner surface 21 as viewed from the inner surface 21 side. It is formed as an opening whose outline is defined by the side 42 in contact therewith.

  Next, as shown in FIG. 5, a V-shaped notch 32 (a first notch 32) spreading toward the inner surface 21 when viewed from the upper surface 23 and the lower surface 24 side in each of the upper surface 23 and the lower surface 24 in the processing region 12. Notch). More specifically, the V-shaped apex P of the notch 32 passes through the center of the processing region 12 and extends along the radial direction of the metal tube 10 as viewed from the upper surface 23 and the lower surface 24 side. The notch 32 is formed so that the apex P is located at a predetermined distance a from the side (first side) 43 in contact with the inner surface 21 on the upper surface 23 and the lower surface 24 of the processing region 12. . The predetermined distance a is shorter than the outer diameter of the metal tube 10, that is, a side (second side) 46 that does not oppose the side 43 in contact with the inner side surface 21 on the upper surface 23 and the lower surface 24 of the processing region 12. There is no particular limitation as long as it is shorter than the length of the end 14a (14b) of the processing region 12. However, the predetermined distance a is 3 minutes of the length of the side (second side) 46 not facing the side 43 so that the elbow shape portion 92 of the manufactured elbow pipe 90 has a smooth curve. It is preferable that it is 2 or more.

  Furthermore, in the present embodiment, the apex angle D located at the apex P of the notch 32 is particularly limited as long as it is an angle of less than 180 °, which is selected according to the bending angle B of the elbow shape portion 92. It is not a thing. For example, the angle D is in the vicinity of 90 °.

  Next, as shown in FIG. 6, each of the upper surface 23 and the lower surface 24 passes through the position of the V-shaped apex P of the notch 32 and is parallel to the inner surface 21, from the end portion 14 a to the end portion 14 b of the processing region 12. A piercing line 34 extending to is formed.

  Further, in each of the upper surface 23 and the lower surface 24, as viewed from the upper surface 23 and the lower surface 24 side, the two sides 44 and 45 (see FIG. 6) in the notch 32 are cut off with a part of the sides 44 and 46. A region sandwiched between the insertion lines 34 (regions 50 and 52 indicated by oblique lines in FIG. 6) is cut out. By cutting out as described above, as shown in FIG. 7, two fan-shaped portions 36 are formed in contact with the end portions 14a and 14b of the processing region 12 and having a predetermined distance a as a radius. In the present embodiment, the angle O of the center angle of each sector 36 is particularly limited as long as it is an angle of less than 90 ° selected according to the bending angle B of the elbow shape portion 92 of the elbow pipe 90. However, the angle O of the central angle of each sector 36 is preferably around 45 °.

  Then, as shown in FIG. 8, in each of the upper surface 23 and the lower surface 24, a cut line is formed in a region located on the outer surface 22 side with respect to the cut line 34 when viewed from the upper surface 23 and the lower surface 24 side. A plurality of notches (second notches) 38 are formed along 34. For example, the notches 38 are arranged at equal intervals along the cut line 34. Furthermore, each notch 38 has a V-shape that extends toward the inner surface 21 when viewed from the upper surface 23 and the lower surface 24 side. Moreover, it is preferable that the apex angle E located at the apex Q of the V-shaped notch 38 is 20 ° or less so that the elbow-shaped portion 92 of the elbow pipe 90 to be manufactured has a smooth curve. Specifically, the sum of the arc lengths of the two sector portions 36 and the length excluding the plurality of notches 38 formed from the cut lines 34 (from the length of the cut lines 34 shown in FIG. A plurality of cutouts 38 are formed so that the length of the V-shaped two sides of each cutout 38 is equal to the length obtained by subtracting the sum of the distances between the ends on the inner surface 21 side. In this specification, “equal” does not mean only a mathematically equal case, but there is a difference that is industrially acceptable in the manufacturing process of the elbow pipe 90 and the elbow pipe 90 as a product. It is meant to include cases. Further, in order to simplify the machining operation and reduce the manufacturing cost of the elbow tube 90 while making the elbow shape portion 92 of the manufactured elbow tube 90 have a smooth curve, about 4 to 8 notches 38 are formed. Preferably, six notches 38 are formed.

  It should be noted that the cut surface formed by cutting the metal tube 10 to form the opening 30, the cutouts 32 and 38, the cut line 34, and the fan-shaped portion 36 is subjected to polishing or the like for welding to be performed later. It is preferable to perform a surface treatment. In addition, the order of forming the opening 30, the notches 32 and 38, the cut line 34, and the sector 36 in the above-described processing step S120 does not necessarily have to be formed in the order described above. In the present embodiment, as a result, the order is not limited as long as the metal tube 10 is processed so as to be in the form shown in FIG.

(Curving step S130)
Then, a bending step S130 for bending the metal tube 10 processed in the processing step S120 is performed. Specifically, in the bending step S130, as shown in FIG. 9, the metal tube 10 is bent around the center line C so that the opening 30, that is, the inner side surface 21, is located inside. At this time, in the present embodiment, since the processing described above is performed on the metal tube 10 in the processing step S120, the metal tube 10 can be easily bent with a small force. That is, in this embodiment, using a device such as a bender as in the prior art, a large force is applied to the other of the metal tube while the metal tube is fixed, and the metal tube is bent. There is no need to do work. Further, in the present embodiment, since a large force is not applied to the metal tube 10, a cross-sectional change such as the metal tube 10 being partially crushed in the elbow shape portion 92 of the elbow tube 90 after manufacture, There is no occurrence of wrinkles or folds on the surface of the tube 10. As a result, according to the present embodiment, it is possible to obtain the elbow pipe 90 having the elbow shape portion 92 having a smooth surface and curved into a desired shape.

(Welding process S140)
Further, a welding step S140 for welding the processing region 12 of the metal pipe 10 bent in the bending step S130 is performed. Specifically, the edges of the openings 30, the edges of the fan-shaped parts 36, the edges of the notches 38, the cut line 34 and the arc of the fan-shaped part 36, which are brought into contact with each other by the above-described bending step S 130, are connected to each other. Weld. At this time, it is preferable to perform welding by argon welding or the like. Further, after welding, it is preferred to polish the weld to form a smoother surface.

  As described above, the elbow pipe 90 shown in FIG. 1 can be manufactured by the manufacturing method according to this embodiment.

<Summary>
By the way, as described above, in the prior art, when manufacturing an elbow pipe, the other end of the metal pipe is fixed while fixing one end of the straight metal pipe using a device such as a bender. A large force is applied to the end portion to perform bending to bend the metal tube. However, since bending is performed by applying a large force to the metal tube, cross-sectional changes such as partial collapse of the metal tube, wrinkles, creases, etc. on the surface of the metal tube in the elbow shape part of the manufactured elbow tube Likely to happen. Therefore, it has been difficult to obtain an elbow tube having an elbow shape portion curved into a desired shape while maintaining a smooth surface using the conventional technology.

  Therefore, in the above-described embodiment, the rectangular opening 30 is formed in the inner surface 21 of the processing region 12 in the metal tube 10, and the upper surface 23 and the lower surface 24 that are not opposed to the inner surface 21 in the processing region 12. And V-shaped notches 32 extending toward the inner surface 21 are formed. According to this embodiment, the metal tube 10 can be easily bent with a small force by forming the opening 30 and the notch 32 as described above. That is, in the present embodiment, using a device such as a bender as in the prior art, a large force is applied to the other end of the metal tube while fixing one end of the metal tube, There is no need to perform the work of bending the tube. As a result, in the present embodiment, in the elbow shape portion 92 of the elbow pipe 90 after manufacture, a cross-sectional change such as the metal pipe 10 being partially crushed, wrinkles, creases, etc. on the surface of the metal pipe 10 occurs. Can be avoided. Therefore, according to the present embodiment, it is possible to easily manufacture the elbow pipe 90 having the elbow shape portion 92 that is curved into a desired shape while maintaining a smooth surface.

  Furthermore, in the above-described embodiment, after the formation of the notch 32, the upper surface 23 and the lower surface 24 pass through the position of the V-shaped apex P of the notch 32, and the other end portion from the one end portion 14 a of the processing region 12. A cut line 34 extending to 14b is formed. In the present embodiment, for each of the two sides in the cutout 32, a region sandwiched between a part of the side and the cut line 34 is cut out, and the two sector portions 36 having a predetermined distance a as a radius are cut out. Form. Furthermore, in the present embodiment, a plurality of cutouts 38 are formed along the cut lines 34 on the upper surface 23 and the lower surface 24 where the two fan-shaped portions 36 are formed. By forming the cut line 34, the sector 36, and the notch 38 as described above, according to the present embodiment, the metal tube 10 can be smoothly bent smoothly with a smaller force. Therefore, according to this embodiment, in the elbow shape part 92 of the elbow pipe 90 after manufacture, a cross-sectional change such as the metal pipe 10 being partially crushed, wrinkles, creases, etc. on the surface of the metal pipe 10 occurs. Can be avoided. As a result, according to the present embodiment, it is possible to easily manufacture the elbow pipe 90 having the elbow shape portion 92 curved into a desired shape while maintaining a smooth surface.

<Modification 1>
In the above-described embodiment, the machining operation for forming the notch 38, the cut line 34, and the sector 36 may be omitted in the machining step S120. That is, as a first modification of the present embodiment, in the processing step S120, a rectangular opening 30 is formed on the inner side surface 21 of the processing region 12 in the metal tube 10 so as to face the inner side surface 21 in the processing region 12. V-shaped notches 32 that extend toward the inner surface 21 may be formed on the upper surface 23 and the lower surface 24 that are not formed. In this case, the metal tube 10 is processed to the state shown in FIG. 5, and the bending step (S130) and the welding step (S140) are performed on the processed metal tube 10. By doing in this way, the elbow pipe 90 which has the elbow shape part 92 curved to the desired shape can be obtained, simplifying a process operation and suppressing the manufacturing cost of the elbow pipe 90. However, in order to easily manufacture the elbow tube 90 having the elbow shape portion 92 curved into a desired shape while maintaining a smoother surface, in the processing step S120 according to the present embodiment, the notch 38, the score line It is preferable that the process operation | work which forms 34 and the fan-shaped part 36 is performed.

<Modification 2>
In the above-described embodiment, in the processing step S120, the upper surface 23 and the lower surface 24 are formed with a plurality of cutouts 38 having a V shape extending toward the inner surface 21 and arranged along the cut line 34. It was. However, in the present embodiment, the shape of the notch 38 is not limited to the V shape, and may be another shape. Below, with reference to FIG.10 and FIG.11, the notch 40 as the modification 2 of this embodiment is demonstrated. FIG. 10 is an explanatory diagram for explaining a process in the manufacturing method of the elbow tube 90 according to the second modification of the present embodiment, and more specifically, a top view of the metal tube 10 viewed from the upper surface 23 side. This corresponds to the process shown in FIG. FIG. 11 is an enlarged view of the region F in FIG.

  As shown in FIG. 10, the notch 40 in FIG. 8 has a trapezoidal shape that expands toward the inner surface 21 when viewed from the upper surface 23 and the lower surface 24 side. In other words, the notch 40 has a trapezoidal shape having a long bottom side on the inner surface 21 side. As shown in FIG. 11, it is preferable to form the notch 40 such that an angle G formed by two sides corresponding to the trapezoidal leg of the notch 40 is an angle of 20 ° or less. Further, similarly to the above-described embodiment, the sum of the arc lengths of the two sector portions 36 and the length excluding the plurality of notches 40 formed from the cut lines 34 (the cut lines shown in FIG. 10). The plurality of notches 40 are formed so that the length of 34 is equal to the length obtained by subtracting the sum of the lengths of the long bases of the trapezoids of each notch 40). In order to simplify the machining operation and reduce the manufacturing cost of the elbow tube 90 while making the elbow shape portion 92 of the manufactured elbow tube 90 have a smooth curve, about 4 to 8 notches 40 are formed. Preferably, six notches 40 are formed.

<Supplement>
In the above-described embodiment, the material in the manufacturing method according to the present embodiment has been described as the metal tube 10 made of a metal material, but the material is not limited to the metal tube made of a metal material. For example, a plastic tube made of a material such as polyethylene or polyvinyl chloride may be used as the material.

  Further, the metal pipe 10 shown in FIGS. 8 and 10, that is, the metal pipe that has not undergone the bending step S130 and the welding step S140 in the manufacturing method according to the present embodiment, can be used as an assembly member or a construction member. is there.

  Hereinafter, an example of a metal tube as an assembly member or a construction member will be described with reference to FIG. FIG. 12 is an explanatory diagram for explaining the metal tube 20 according to the present embodiment, and is a top view of the metal tube 20 as viewed from the upper surface 23 side. When viewed from the lower surface 24 side of the metal tube 20, the metal tube 20 is shown in the same manner as in FIG. 12, and when viewed from the inner surface 21 side, the metal tube 20 is shown. Is shown in FIG.

  Specifically, the metal tube 20 is a straight rectangular metal tube, and has a rectangular opening 30 (see FIG. 4) provided on the inner surface 21 of the metal tube 20, and the inner surface 21. You may have the V-shaped notch 32 (refer FIG. 12) which was formed in the upper surface 23 and the lower surface 24 which are not opposing, respectively, and spreads toward the inner surface 21. FIG.

  Furthermore, another example of the metal tube as an assembly member or a construction member will be described with reference to FIG. FIG. 13 is an explanatory diagram for explaining the metal tube 60 according to the present embodiment, and is a top view of the metal tube 60 viewed from the upper surface 23 side. When viewed from the lower surface 24 side of the metal tube 60, the metal tube 60 is shown in the same manner as in FIG. 13, and when the metal tube 60 is viewed from the inner side surface 21, the metal tube 60 is shown. Is shown in FIG.

  As shown in FIG. 13, the metal tube 60 has an opening 30 and a notch 32, similar to the metal tube 20, passes through the position of the V-shaped apex of the notch 32, and the upper surface 23 and the lower surface 24. 2 further includes a cut line 34 extending in parallel with the side 43 in contact with the inner surface 21. Further, the metal tube 60 is formed by cutting a region sandwiched between a part of the sides 44 and 45 and the cut line 34 for each of the two sides 44 and 45 in the notch 32. Two fan-shaped portions 36 are in contact with a part of each side 44, 45. Further, the metal tube 60 has a plurality of cutouts 38 arranged along the cut line 34.

  In addition, the said metal pipes 20 and 60 are the same as that of the metal pipe 10 shown by FIG. 8 in the above-mentioned embodiment about the material, thickness, an outer diameter, the shape of a cross section, etc. Further, the width of the opening 30, the predetermined distance a, the angle of the central angle O of each sector 36, the shape, angle, number, etc. of the notches 38 are also shown in FIG. 8 in the above embodiment. The same as the metal tube 10.

  As described above, the metal tubes 20 and 60 having the above-described form are fixed to one end of the metal tube using a device such as a vendor, while the other end of the metal tube is fixed. Without bending the metal tube 20 by applying a large force to the part, the metal tube 20 can be bent easily with a small force. Therefore, by using the metal tubes 20 and 60 according to the present embodiment as an assembly member or a construction member, an assembly manufacturing operation using a curved tube at a manufacturing site or a construction site where there is no special device such as a vendor, or Construction work can be performed easily.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

10, 20, 60 Metal tube 12 Processing region 14a, 14b End portion 21 Inner side surface 22 Outer side surface 23 Upper surface 24 Lower surface 30, 46 Opening portion 32, 38, 40 Notch 34 Cut line 36 Fan-shaped portion 41, 42, 43, 44 , 45, 46 Side 50, 52, F region 90 Elbow tube 92 Elbow shape part a Distance B, D, E, G, O Angle C Center line P, Q Vertex

Claims (9)

A manufacturing method for manufacturing an elbow pipe having an elbow shape from a straight rectangular metal pipe,
A rectangular opening is formed on the first surface of the processing area processed into the elbow shape in the square metal tube,
Forming a V-shaped first notch extending toward the first surface on each of the second surface and the third surface not facing the first surface in the processing region;
Curving the square metal tube so that the opening is located inside the elbow shape;
Welding the machining area;
A method for manufacturing an elbow pipe. Each of the first cutouts in the second surface and the third surface is from a first side where the vertex of the V-shape contacts the first surface in the second surface and the third surface. Formed to be separated by a predetermined distance,
The predetermined distance is shorter than the length of the second side that does not oppose the first side in the second surface and the third surface of the processing region,
The manufacturing method of the elbow pipe of Claim 1.   The elbow pipe manufacturing method according to claim 2, wherein the predetermined distance is two-thirds or more of the length of the second side. After formation of the first notch,
A cut line is formed in the second surface and the third surface, passing through the position of the V-shaped apex of the first notch and extending from one end of the processing region to the other end. ,
For each of the two sides in the first cutout, cut out a region sandwiched between a part of the side and the cut line, and form two sectors having a radius of the predetermined distance,
A plurality of second cutouts are formed along the score line in the second surface and the third surface where the two fan-shaped portions are formed;
Further including
The manufacturing method of the elbow pipe of Claim 2 or 3.   The plurality of second cutouts are formed such that the sum of the arc lengths of the two sector portions is equal to the length excluding the plurality of second cutouts formed from the cut lines. The method for manufacturing an elbow pipe according to claim 4.   Each of the said 2nd notch is a manufacturing method of the elbow pipe | tube of Claim 4 or 5 which has a V-shaped shape extended toward the said 1st surface.   The elbow tube manufacturing method according to claim 6, wherein an angle of the V-shaped apex of each of the second cutouts is 20 ° or less.   Each of the said 2nd notch is a manufacturing method of the elbow pipe | tube of Claim 4 or 5 which has the trapezoid shape which spreads toward the said 1st surface. A straight rectangular metal tube,
A rectangular opening provided on the first surface of the rectangular metal tube;
A V-shaped first notch that is provided on each of the second surface and the third surface that are not opposed to the first surface in the rectangular metal tube and that extends toward the first surface;
A square metal tube.

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