JPH08309429A - Bending method for hollow angular tube - Google Patents

Abstract

PURPOSE: To obtain a bent tube product having light weight, toughness, smart design and high quality by providing a notched groove part on a hollow angular tube using a prismatic die, bending and forming the tube with the notched groove part bent. CONSTITUTION: A notch part S is formed on an arbitrary position with a prismatic die 1, next, a bending part is bent to join like a bending and joining part T, which is just only bent inward with a manual operation or a device in this joining method. The bending and joining part T is rounded like (b) in order to facilitate bending and to eliminate not only shrink of the wall due to plasticity by bending into a desired angle but also collision to avoid spring back. The slope angle of blade edge 5 of the prismatic die 1 are specified to be 40.5 deg. and 49.5 deg. so as to completely join the bending and joining part T without any gap at its part (a).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for bending a square pipe, and more particularly to a method for bending a hollow square pipe by cutting out a hollow square pipe to assemble it into a desired shape.

[0002]

2. Description of the Related Art V-bending, U-bending, end bending, etc. are often used in a die bending process in which a generally used bending die is attached to a press or a press brake. All of these are used for bending iron plates, metal rods, etc., and were not suitable for square pipes such as so-called hollow square pipes. So iron pipe,
When you want to bend and use a hollow square pipe such as steel pipe, lead pipe, aluminum pipe, cut it with a saw or a cutter, or insert a core metal into the pipe and cut it with a mold before welding. It was Therefore, it takes a lot of time and labor for cutting and welding work, and since the welding is welding, the internal fillet welding is impossible and the breaking strength is weak and it may break or peel off after long-term use. Lost its function,
Further, there were many problems in appearance. That is, it has heretofore been impossible to bend a square pipe such as a single elongated hollow square pipe at a desired position or continuously bend it at various angles.

Therefore, the applicant of the present invention has developed bending processing of a square pipe, which has been impossible in the past by many years of research, and disclosed the technical contents (Japanese Patent Laid-Open No. 54-122668). This conventional invention has developed a bending forming process for a square pipe such as a hollow square pipe, which has been considered impossible in the past, and has a columnar metal member having a rounded tip and a corrugated blade edge. By bending the notch at the bending point of the bent member without the core metal by the pressure notching device consisting of the upper mold having the mold attached thereto and the lower mold having the columnar mold fitting groove provided therein, The purpose is to provide a square pipe bending mechanism that can bend any shape of a single hollow square pipe to a desired shape by changing the mold at any angle. To do.

Further improvements have been made thereafter, and
63-199029 No. square pipe bending mechanism was developed. The improved invention is a hollow corner which is composed of an upper mold having a columnar mold having a notch blade of a hollow square pipe attached thereto, and a lower mold having a fitting groove for the columnar mold and a fixing groove for the hollow square pipe. In a square pipe bending mechanism for bending and forming a hollow square pipe by using a pipe notch device, a blade edge having a thick wall portion of an inclined surface is formed on the blade portion of the columnar mold, and θ1 is formed at the tip portion. And an inclination angle of θ2 are formed, and a cutting force and a pressing force on the hollow square pipe by the blade portion are adjusted and held, and a purpose thereof is a hollow angle. The point is to get a good and good cut of the pipe easily and easily.

[0005]

In the bending welded structure of the hollow square pipe formed and processed by the conventional processing method as described above, especially when there are a plurality of bending points, the members at the bending portions are required to have the required lengths. Depending on the situation, a saw, a cutter, or a mold having a cored bar inserted therein is cut and then perforated to form a welded structure. Therefore, production control, process control, quality control, etc. are required for each member of the bent portion, which requires a lot of time and effort. Also, in quality maintenance, it is difficult to maintain stable quality because the following problems occur frequently. A. It is difficult to weld the two sides with a 45 degree angle cut surface. B, It is difficult to make the hole size from the stay (45 degree angle). C) Wrong mounting during welding and difficult positioning of corner members. D) Deformation occurs due to thermal strain at the welded part. E, the finish shape of the retained welding part is not good, and the strength after finishing is weak.

[0006] Such problems pose many obstacles to the chain-like bending process, and particularly in the recent refinement of OA equipment, even precision sheet metal products for accommodating and accommodating them and the conventional sheet metal processing precision are inferior. The limit has been exceeded, and the precision requires a dimensional tolerance in the micron unit for welded structures, and at the same time, a stable supply is always required.

Therefore, in the current bent structure of a hollow square pipe, cutting is performed due to crushing at the time of cutting with a blade edge die whose joint surface of the bent portion is flat, and roughness of cutting accuracy with a saw or a cutter. On the surface, there is a tolerance of about 0.5 mm. In addition, since welded joints are required on the curved surface and it is impossible to weld the internal fillet, the fracture strength is weak and it will break or peel off after long-term use, and its function will be lost. . Further, there are many problems in appearance, and stable quality cannot be supplied.

[0008]

The present invention was developed in order to solve the above-mentioned problems, and a hollow square pipe is provided with a notched groove portion using a columnar mold, and the notched groove portion is bent to form a hollow portion. A method of bending a square pipe, comprising a first step of forming a grooved notch of a desired shape in a hollow square pipe using the columnar mold, and a hollow square pipe having the grooved notch. A second step of forming a V-shaped notch with a desired angle, a third step of bending the notch of the hollow square pipe having the notch and welding a bent portion, and a desired hollow square pipe by the welding process. And a fourth step of assembling and processing the product described in (4) above. Also, the method is a hollow square pipe bending method in which the bent portion is welded by laser welding.

That is, the present invention is the "FITS method" (F
LEXIBLE INTEGRATED TOOLIN
G SYSTEM), which is the development of a hollow square pipe bending method by the so-called "one-stroke writing method" (Hitofu degaikoho).

[0010]

[Action]

(1) Using a columnar mold to provide a hollow groove pipe with a cutout groove,
A method for bending a hollow square pipe by bending the cutout groove portion, comprising a first step of forming a grooved cutout portion having a desired shape in the hollow square pipe using the columnar mold, and the grooved cutout portion. A second step of forming a V-shaped cutout portion having a desired angle in the hollow square pipe having a groove, a third step of bending the cutout portion of the hollow square pipe having the cutout portion and welding a bent portion, and the welding Since it is composed of a fourth step of assembling and processing a product of a desired hollow square pipe by working, particularly in the chain bending method, three sides of the hollow square pipe are cut out at a desired angle, Not only can it be bent at an angle, but it can also be bent into a shape that is not continuous. Further, according to this processing method, the bent bent portion has many advantages such as reduction of welding portion, suppression of heat distortion, elimination of finishing man-hours, simplification of parts management, high quality maintenance, and high manufacturing efficiency. be able to.

(2) Since the bent portion is welded by laser welding, welding can be performed by laser welding other than arc welding and electric welding.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hollow square pipe bending method of the present invention will be described below with reference to the drawings. 1 to 3 illustrate the processing steps of the present invention. First, FIG. 1 shows a method of forming a cutout groove portion in a hollow square pipe by using a columnar mold (not shown), bending the cutout groove portion, and bending-forming the hollow square pipe. And a second step of forming a groove-shaped notch of a desired shape in a hollow square pipe and a second step of forming a V-shaped notch of a desired angle in the hollow square pipe having the groove-shaped notch. It is a thing. Next, FIG. 2 shows a third step of bending the cutout portion of the hollow square pipe having the cutout portion and welding the bent portion. Then, FIG. 3 shows a fourth step of assembling and processing a desired hollow square pipe product by the welding process. The specific work process will be described later.

FIGS. 4 to 8 show concrete processing by the processing method of the present invention. 4 to 6 show a working die used in the hollow square pipe bending method of the present invention, and 1 is a columnar die thereof.
The columnar mold 1 includes a base portion 2, a columnar portion 3, and a blade portion 4. The base portion 2 is formed with a semicircular R portion that removes scraps generated at the time of the notch, and the columnar portion 3 has a substantially triangular shape and is integrally formed with the base portion 2. The blade portion 4 is provided with a linear blade edge 5 that is inclined from the tip portion 6 of the ridge portion to one end of both edges of the R portion of the base portion 2. The reason why the tip 6 is rounded along the ridge is to make the notch good and to strengthen the tip 6. In the columnar mold 1 configured as described above, the blade edge 4 is provided with the blade portion 4 having the inclined surface and the thick portion, and the tip portion 6 is further provided.
An inclined surface is formed on. This is to obtain the same effect as that of the conventional wave-shaped wave-shaped blade portion. By this inclined surface, the balance between the cutting force and the pressing force can be maintained and the square pipe can be cut rationally.

FIG. 4 shows a method of forming a hollow square pipe using the columnar mold of the present invention shown in FIG. First, a notch S is formed at an arbitrary position of a hollow square pipe P by a columnar mold 1 shown in (a) as shown in (b), and then a bent part is bent as shown in (c) to make a bent joint T. To join. This joining method may be manually or only folded inward using an instrument. The bent joint T has a rounded shape as shown in b in order to facilitate bending and to bend at a desired angle so as to avoid clogging or collision due to plasticity and to eliminate springback. In particular, in the columnar mold 1 according to the present invention, the blade edge 5
The inclination angles of 40.5 degrees and 49.5 degrees are set in order to completely join the bent joint portion T at the portion a as shown in FIG.

In this embodiment, the method of bending the hollow rectangular pipe at a right angle has been described, but the bending member is not limited to this, and the same effect can be obtained with any rectangular pipe, and it can be bent into any shape. According to this principle, the same effect can be obtained not only with a square pipe but also with a pipe of any shape such as a triangle, a circle, or a trapezoid.

FIG. 8 shows a bending forming apparatus for a square pipe which is used in the use of the columnar mold according to the present invention. As is clear from this figure, the columnar mold 1 is fixed to the upper mold of the apparatus, and the lower mold G is formed to have a concave cross section. By placing an intermediate square pipe P on the lower mold G and pushing the upper mold H downward, the square pipe P can be cut out in a triangular shape. That is, the blade edge of the tip of the pillar-shaped mold 1 is made to be cut into the inner wall surface of the side of the hollow square pipe P, and at the same time, the blade edge is cut to the side of the hollow square pipe P. In this case, since the blade edge tends to stand up, the blade portion efficiently cuts the side by the so-called "wedge principle". Then, since the blade edge gradually becomes sluggish, the force to cut the side is weakened by the "wedge principle" in the same manner as described above, but the force pressing the side portion to be cut becomes large, so the pressing force is increased. The cutting force of the blade portion that tries to tear the cut edge is applied under pressure by the "lever principle", and the cutting progresses further, and the chips are cut off as if they were wound around the R portion.

[0017]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, the hollow square pipe has better notches and higher quality than the conventional method, so that not only a good bent pipe product can be obtained, but also the following. It has many specific effects such as: Oh, the design man-hour can be shortened and smart design can be done. B. A light and durable design can be achieved, such as three times the strength of the same cross-sectional area. C) The flat surface makes it easy and easy to attach parts, and the number of parts is only one. D. There are few welding points, and since there are few welding points, there is little heat distortion and deformation, and there are also few finishing points. E. Furthermore, since there are few welding points, not only parts management and quality control are easy, but also installation mistakes are eliminated.

By this processing method, the following many effects can be further obtained. A. Compared with the conventional method of bending from cutting to welding, not only can more accurate and reliable bending work, but the material is entangled to the inner fillet that welding does not reach, so it is similar to fillet welding. Strength is obtained. B. Since the core metal is not used even when making a notch, anyone can easily perform the notch operation without requiring a high level of skill in press working. C. After the notch, depending on the member, it can be bent easily with both hands, so the notch member can be bent at the work site. Since the bent portion is clean and can be bent into various shapes, it can be used for decoration or the like and can be applied to a wide range. E. Notches and bending work are easy, and mass production is possible, so it is economical. (F) If several types of dies are manufactured one by one, they can be used for many years, so that a low-cost notch device can be obtained and put into practical use.

[Brief description of drawings]

FIG. 1 is an explanatory schematic diagram showing a processing step of the present invention.

FIG. 2 is an explanatory schematic diagram showing a processing step of the present invention.

FIG. 3 is an explanatory schematic diagram showing a processing step of the present invention.

FIG. 4 is a perspective view showing a columnar mold according to the present invention.

FIG. 5 is a schematic explanatory view showing the shape of the mold shown in FIG.

FIG. 6 is a schematic explanatory view showing a main part of the mold shown in FIG.

FIG. 7 is a schematic explanatory view showing a usage state of the mold shown in FIG.

FIG. 8 is a schematic explanatory view of a processing apparatus using the mold shown in FIG.

[Explanation of symbols]

 1 Columnar mold 2 Base part 3 Columnar part 4 Blade part 5 Blade edge 6 Tip part P Hollow square pipe S Notch part M Worker E table T Bending joint part H Upper part G Lower part F Assembly product

Claims (2)

[Claims] 1. A method for forming a cutout groove portion in a hollow square pipe by using a columnar mold, and bending the cutout groove portion to bend and form the hollow square pipe, wherein the hollow square pipe is formed by using the columnar mold. A first step of forming a groove-shaped notch having a desired shape, a second step of forming a V-shaped notch having a desired angle in the hollow square pipe having the groove-shaped notch, and the hollow corner having the notch A method for bending a hollow square pipe, comprising a third step of bending a cutout portion of the pipe and welding the bent portion, and a fourth step of assembling and processing a desired hollow square pipe product by the welding process. 2. The method for bending a hollow square pipe according to claim 1, wherein the bent portion is welded by laser welding.