JP6366144B2 - Octagonal pipe swaging method and octagonal pipe - Google Patents

Description

  The present invention relates to a swaging method for swaging an octagonal pipe, and an octagonal pipe manufactured by the processing method.

For example, steel pipes are widely used as frameworks for agricultural houses. The framework of this type of agricultural house is composed of, for example, an agricultural house framework 10 shown in a simplified form in FIG. And a plurality of horizontal pipes 12 which are fixed to the arched pipes 11 by fixing means (not shown) at the portions intersecting with the arched pipes 11 and maintaining the intervals between the arched pipes 11. Widely done.
Since especially the horizontal pipe 12 of this house framework is the length of a house depth and becomes long, normally, it connects and uses a some straight pipe. Further, the arched pipe usually has a portion for connecting the pipes together.

The connection between the pipes in the horizontal pipe 12 or the connection between the pipes in the arched pipe 11 is made by tapering the one end side of each pipe to be connected by reducing the diameter by swaging. This is generally performed by inserting the portion into a normal pipe cross-sectional portion that is not reduced in diameter on the other end side (FIG. 7 of Patent Document 1).
In addition, when the tip is tapered, the entire tapered portion is tapered, and the tapered portion that transitions to the normal pipe cross section is shortened by providing a uniform small diameter portion at the tip of the tapered portion. There is a case to do.

  By the way, although a round pipe is generally used as a framework pipe of an agricultural house, an octagonal pipe (a pipe having an octagonal cross section) may be used (Patent Document 2).

JP 2003-77 A JP2015-39358

In the case of a round pipe, it is easy to swage to reduce the diameter and taper, but in the case of an octagonal pipe, it is not always easy to swage into a tapered shape with a uniform cross section.
The inventor of the present application conducted an experiment in which an octagonal pipe was swaged into a tapered shape using a die having a tapered shape while the cross-sectional shape of the inner surface of the die was an octagonal similar shape in the longitudinal direction of the pipe. However, each side buckled and does not have a reduced diameter octagonal cross section consisting of flat sides, and each side does not buckle unevenly and does not have a uniform cross-sectional shape in the circumferential direction (each side has a uniform shape). A tapered octagon pipe with a good appearance was not obtained.
Also, in a tapered octagonal pipe that transitions to a normal octagonal pipe cross section where the diameter-reduced portion is not reduced in diameter in the circumferential direction, the tapered portion of one octagonal pipe is the end of the other octagonal pipe. When inserting and connecting to a normal octagonal pipe cross section where the diameter is not reduced, there may be cases where smooth insertion and connection are not possible.

  The present invention has been made in view of the above circumstances, and when octagonal pipes are reduced in diameter by swaging, the octagonal pipe is capable of obtaining a reduced-diameter octagonal cross section having a good appearance with a uniform cross-sectional shape in the circumferential direction. It is an object to obtain a swage processing method and an octagonal pipe manufactured by this processing method, particularly a tapered octagonal pipe.

The invention of claim 1 for solving the above-mentioned problem is a method for swaging an octagonal pipe for swaging a metal octagonal pipe,
Each side has a flat octagonal cross section on the inlet side, and protrudes toward the center of the die in such a manner that the amount of protrusion gradually increases from the inlet side to the outlet side at the center of each of the eight sides of the small-diameter octagon on the outlet side. The octagonal pipe is relatively pushed into a die of a tapered deformed cylindrical inner surface having a protruding portion, and the diameter is reduced to a deformed octagonal cross-sectional shape in which each central portion of each of the eight sides of the octagon is recessed. To do.

  According to a second aspect of the present invention, in the swage processing method for the octagonal pipe according to the first aspect, the protrusion heights of the protrusions on the four sides in two directions at right angles out of the eight sides on the tapered deformed cylindrical inner surface It is characterized in that the octagonal pipe is relatively pushed into a die which is higher than the protruding height of the protruding portion on the side to reduce the diameter.

The octagonal pipe of the invention of claim 4 is
An octagonal pipe manufactured by the swage processing method according to claim 1 or 2, wherein a tip portion of a long octagonal pipe is swaged, and only the tip portion is recessed inward in the center of each of the eight sides of the octagon. It is characterized by an irregular octagonal cross-sectional shape.

According to the swage processing method of the first aspect of the present invention, a reduced-diameter octagonal cross section (a reduced octagonal cross-section having a reduced diameter) having a uniform cross-sectional shape in the circumferential direction (the shape and distance from the pipe center of each side are equal) is good. ) Can be obtained.
Therefore, when a tapered octagonal pipe (octagonal pipe of claim 4) having a reduced octagonal cross section at the tip of a long octagonal pipe is manufactured by this swage processing method, the tapered octagonal pipe is, for example, a pipe for an agricultural house. It is suitable for use as a frame. In this case, since the reduced-diameter octagonal cross section of the tapered portion has a uniform cross-sectional shape in the circumferential direction, the tapered portion of one octagonal pipe is inserted into and connected to the non-reduced octagonal cross-sectional portion of the end of the other octagonal pipe. In doing so, a smooth plug connection can be achieved.

  In addition, the degree of processing when swaging into a similar octagonal cross section reduced in diameter while maintaining the octagonal section and the degree of processing when swaging into a deformed octagonal cross section reduced in diameter according to the processing method of the present invention are respectively When the pipe diameter (distance between opposite sides) is made the same (the diameter of the material octagonal pipe is the same and the diameter of the reduced octagonal pipe is also the same), the circumference of the odd-shaped octagonal cross section according to the present invention (plate) (Perimeter along the thickness center line) is longer than the perimeter of the similar octagonal cross section, so the degree of processing of swaging by the processing method of the present invention is smaller. Therefore, it can be said that the processing method of the present invention that requires only a small degree of processing is advantageous mainly in terms of processing equipment.

  As in claim 2, the protruding height of the protruding portion of the four sides in two directions at right angles out of the eight sides of the tapered deformed cylindrical inner surface is made higher than the protruding height of the protruding portion of the other four sides. By using a die, it is possible to easily obtain a reduced-diameter octagonal cross section having a good external appearance with a uniform cross-sectional shape in the circumferential direction.

The dice | dies used with the swage processing method of one Example of this invention are shown, (A) is a front view, (B) is sectional drawing of (A), AA cross section, BB sectional drawing, C- The figure which showed both C cross sections, (c) is a cross-sectional view of the octagonal pipe which is the object of swaging in the embodiment. (A)-(d) is a figure explaining the process which swages an octagonal pipe using the dice | dies of FIG. 1, (e) is EE sectional drawing of (d). (A) is a DD enlarged sectional view in FIG. 2 (d), (b) is an EE enlarged sectional view in FIG. 2 (d) (an enlarged view of FIG. 2 (e)). It is a perspective view of the front-end | tip vicinity of the front-end | tip part diameter reduction octagon pipe processed by the said swage processing method. It is a figure explaining the connection state in the case of connecting the two front-end | tip diameter reduction octagonal pipes which each formed the taper part in the one end side. It is a figure explaining the case where the edge part of a normal octagon pipe without a taper is connected with the both sides of the short tip part diameter reduction octagon pipe which formed the taper part in both ends. It is a perspective view which shows an example of the pipe framework of the agricultural house which it is going to assemble using the said front-end | tip reduced diameter octagonal pipe.

  Hereinafter, a method for swaging an octagonal pipe and an embodiment for implementing the octagonal pipe of the present invention will be described with reference to the drawings.

1A and 1B show a die 1 used in a swaging method according to an embodiment of the present invention. FIG. 1A is a front view, FIG. 1B is a sectional view of FIG. FIG. 2 is a cross-sectional view of the octagonal pipe 2 to be swaged in the embodiment. FIG.
FIG. 2 is a diagram for explaining a machining process for swaging the octagonal pipe 2 using the die 1 of FIG. 1, and the machining is performed in the order of (a) to (d).
3 (a) is a DD enlarged sectional view in FIG. 2 (d), (b) is an EE enlarged sectional view in FIG. 2 (d) (an enlarged view of FIG. 2 (e)), and (c). FIG. 3 is a cross-sectional view of a tapered portion (hatching is omitted).

The octagonal pipe 2 to be swaged in the illustrated example is a straight pipe (round pipe) having a thickness t = 1.6 mm and an outer diameter of 42.7 mm, which is shaped into an octagonal pipe by a roll forming machine. h is about 39.5 mm.
The dice 1 in the illustrated example has an octagonal inner surface (an octagon of material) between the circular inner surface (cross-sectional inner surface) of the opening position on the inlet side (the right end portion in FIG. 1 (b)) and the FF cross-sectional position in the drawing. pipe 2 corresponding to an outer surface shape) to have introduced the inner surface S ₁ of graded, the generally F-F sectional position irregular octagonal inner surface 3 of the final stop position of the outlet side from the octagonal inner surface (FIG. 1 (b) see) diameter until having a tapered profiled tubular inner surface S ₂ be reduced in a tapered shape.
In the embodiment, the distance between the inner surfaces of the AA cross section is 30.5 mm, the distance between the inner surfaces of the BB cross section is b = 34.0 mm, and the distance between the inner surfaces of the CC cross section is c.38.47 mm. The outer diameter D of the die 1 is 70 mm, and the width W is 40 mm.

As shown in FIG. 1 (a), the odd-shaped octagonal inner surface 3 has a protrusion 3a protruding toward the center of the die at the center of four sides of the AA cross-sectional position and the direction orthogonal thereto, A protrusion 3b protruding toward the center of the die is provided at the center of the four sides of the -B cross section and the direction orthogonal thereto, and is positioned at the middle part (CC cross section position) of the two protrusions 3a and 3b. There are recesses 3c at 8 places. That is, the odd-shaped octagonal inner surface 3 has an octagonal cross section with flat sides on the inlet side, and gradually protrudes from the inlet side to the outlet side at the center of each of the eight sides of the small-diameter octagon on the outlet side. protrusion 3a protruding die roll center side in a manner to increase, and a 3b. The protrusion 3a is higher than the height of the protrusion 3b (difference between the dimension a and the dimension b).
Although the protrusion heights of the protrusions on each of the eight sides may be the same, the protrusion heights of the protrusions 3a on the four sides in the two directions at right angles are made higher than the protrusion heights of the protrusions 3b on the other four sides. In other words, by making the protrusion heights of the protrusions of the adjacent sides alternately different, each side can be easily deformed stably.

When swaging the target octagonal pipe 2 using the above-described die 1, the octagonal pipe 2 is fixedly held by the clamp 5 as shown in FIGS. pushing the tip of the octagonal pipe 2, after the leading end portion of the octagonal pipe 2 is guided by the introducing the inner surface S ₁ of the die 1, it is throttled along the shape of the tapered profiled tubular inner surface S _2, FIG. 3 (B) (same as in FIG. 2 (e)), as shown in (c), the tapered portion 2a of the tip portion is provided with recesses p and q recessed inwardly at the center of each of the eight sides of the octagon. The deformed octagonal cross section having a reduced diameter (reduced octagonal cross section) is obtained. The recesses p on the four sides correspond to the protrusions 3a on the inner surface of the die, the recesses q on the other four sides correspond to the protrusions 3b on the inner surface of the die, and the depth of the recesses p is deeper than the recesses q.
Thus, as shown in perspective view in FIG. 4, tapered octagonal migrating octagonal pipe section 2b that is not reduced in diameter through a tapered reduced diameter portion 2a ₂ from the parallel reduced diameter portion 2a ₁ of the distal end of the tapered portion 2a Pipe 2 'is obtained.
If the die 1 is stopped when the outlet end reaches the tip of the octagonal pipe 2, a tapered octagonal pipe whose whole is a tapered reduced diameter portion is obtained.
In the illustrated example, the octagonal pipe 2 is fixed and the die 1 is moved, but the dice 1 may be fixed and the octagonal pipe 2 may be moved and swaged. That is, it is sufficient if the die and the octagonal pipe are relatively close to each other.

When the above-mentioned tapered octagonal pipe 2 ′ is used, for example, as the frame material of the agricultural house shown in FIG. 7, the house frame is mainly used as an individual pipe constituting the long horizontal pipe 12 corresponding to the depth of the house.
In this case, as shown in FIG. 5, the tapered octagonal pipes 2 ′ are connected to each other at one end of the tapered octagonal pipe 2 ′ (2 ₁ ′) to be coupled with the other tapered octagonal pipe 2. It is carried out by inserting it into the normal octagonal pipe cross section 2b which is not reduced in diameter on the other end side of '(2 ₂ ').
In this case, since each side of the reduced-diameter octagonal cross section of the tapered portion 2a has a uniform cross-sectional shape in the circumferential direction (the shape and distance of each side with respect to the pipe center are equal), the taper of _one octagonal pipe 2 '(2 ₁ ') When the portion 2a is inserted and connected to the non-reduced octagonal cross-sectional portion 2b at the end of the other octagonal pipe 2 ′ (2 ₂ ′), smooth insertion connection can be performed.

  In addition, the degree of processing when swaging into a similar octagonal cross section reduced in diameter while maintaining the octagonal cross section and the degree of processing when swaging into a deformed octagonal cross section reduced by the processing method of the present invention, respectively, When comparing the same diameter (distance between opposite sides) (with the same diameter of the material octagonal pipe and the same diameter of the reduced octagonal pipe), the perimeter of the odd-shaped octagonal section according to the present invention (plate thickness) Since the perimeter along the center line is longer than the perimeter of the similar octagonal cross section, the degree of processing of swaging by the processing method of the present invention is smaller. Therefore, it can be said that the processing method of the present invention that requires only a small degree of processing is advantageous mainly in terms of processing equipment.

Also in the arched pipe 11, when one pipe is not arched, for example, when two semiarched pipes are connected at the top to form an arched shape, for example, the end of one half arched pipe is used. By forming the tapered portion 2a by swaging in the portion, the insertion connection as shown in FIG. 5 can be performed at the top of the arch.
As shown in a simplified manner in FIG. 6, when using a short double-sided taper octagonal pipe 2 ″ having tapered portions 2a at both ends, two semi-arched pipes made of ordinary octagonal pipes having no taper are used. The two side taper octagonal pipes 2 ″ can be connected with each other.

  In the above-described embodiment, the case of using as a framework material of an agricultural house has been described. However, the present invention is not limited thereto, and can be applied to octagonal pipes for various uses.

1 Die 2 Octagonal pipe 2 '(to be swaged) Tapered octagonal pipe 2a (to be swaged) Tapered part (reduced diameter part) of octagonal pipe
2a ₁ Parallel reduced diameter portion 2a ₂ (in the tapered portion) Tapered reduced diameter portion 2b (in the tapered portion) Normal octagonal pipe cross section 3 (in which the octagon pipe is not reduced in diameter) ) Deformed octagonal inner surface 3a Protruding portion 3b (inside of die inner surface) Protruding portion 3c (inside of die inner surface) Recessed portion 5 Clamp S ₁ (inside of die) introduction inner surface S ₂ (in dice) tapered modified cylindrical inner surface 10 Agriculture House frame 11 Horizontal pipe 12 Arch pipe

Claims (3)

A swaging method for octagonal pipes, which swages metal octagonal pipes,
Each side has a flat octagonal cross section on the inlet side, and protrudes toward the center of the die in such a manner that the amount of protrusion gradually increases from the inlet side to the outlet side at the center of each of the eight sides of the small-diameter octagon on the outlet side. The octagonal pipe is relatively pushed into a die of a tapered deformed cylindrical inner surface having a protruding portion, and the diameter is reduced to a deformed octagonal cross-sectional shape in which each central portion of each of the eight sides of the octagon is recessed. How to swage octagon pipes.   Of the eight sides of the tapered deformed cylindrical inner surface, octagonal relative to a die in which the projecting height of the projecting portions of four sides in two perpendicular directions is higher than the projecting height of the projecting portions of the other four sides. 2. A method for swaging an octagonal pipe according to claim 1, wherein the pipe is pressed to reduce the diameter.   An octagonal pipe manufactured by the swage processing method according to claim 1 or 2, wherein a tip portion of a long octagonal pipe is swaged, and only the tip portion is recessed inward in the center of each of the eight sides of the octagon. An octagonal pipe characterized by an irregular octagonal cross section.

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