JPS591490B2 - How to fix flanges on steel pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for fixing flanges on steel pipes.

Conventionally, when forming a flange at the end of a steel pipe, the flange was cut out or an annular disk was welded to the end.

According to this manufacturing method, the former requires a large amount of machining time, requires a skilled machinist, and has the disadvantage of high production costs, while the latter requires a skilled welder. Not only is it necessary, but the finished strength of the welded part is unstable, resulting in variations in quality, resulting in poor reliability, and both are difficult to mass produce.

In view of the above problems, it is an object of the present invention to propose a method for fixing flanges on steel pipes, which enables mass production of flanged steel pipes and provides flanged steel pipes with excellent quality. .

That is, in the method of fixing a flange on a steel pipe of the present invention, a flange member that is punched out so that the inner diameter of the boss portion has an extrapolation tolerance with the outer diameter of the steel pipe is held so as to be located on the outer periphery of the end of the steel pipe. After that, a press jig is pressed from the top and bottom sides of the flange, and the press jig on the top side expands the diameter of the end of the steel pipe, and at the same time, the press jig on the bottom side presses the boss part of the flange member. The outer periphery of the steel pipe and the inner periphery of the flange member boss are hermetically pressed and fixed together.

Further, an annular uneven strip is provided in advance on the outer circumference of the boss of the flange member, and the press jig is pressed to form the uneven strip to reduce the inner diameter of the boss portion, further increasing the airtight pressure welding effect. It is something.

Hereinafter, one embodiment of the present invention will be described in more detail with reference to the drawings. Fig. 1 shows a flange member 1. The flange member 1 is punched out of a steel plate of an appropriate thickness using a press machine.The flange member 1 has a polygonal or annular flat plate outer periphery and a boss bent toward the mouth on the inner edge of the flange part 2. The inner diameter D1 of the boss portion 3 is configured to have a tolerance for extrapolation to the outer diameter D of the steel pipe 4, which will be described later.

The steel pipe 4 has a desired wall thickness and is configured with a flange at its end.

When fixing the flange member 1 and the steel pipe 4, first the steel pipe 4 is inserted into the support hole 7 of the lower die 6 of the press jig 5, as shown in FIG. Lower mold 6
It is positioned so as to protrude from the upper surface 8 of.

The gap d between the support hole 7 (hole diameter D5) of the lower mold 6 and the outer periphery of the steel pipe 4 is considerably smaller than the thickness t of the flange member 1 (d
<<t), the upper surface 8 side support hole 7 becomes an inverted conical tapered hole 9.

The boss portion 3 of the flange member 1 is inserted onto the protruding end of the steel pipe 4 so that the boss portion 3 faces toward the lower die 6 .

At this time, since the inner diameter D1 of the boss portion 3 is molded to have an extrapolation tolerance with respect to the outer diameter D2 of the steel pipe 4, the boss portion 3 is lightly and temporarily held at the extrapolation position.

10 is the upper die of the press jig 5, and the upper die 10 is the lower die 6.
It has a flat lower surface 11 facing the upper surface 8, and a diameter-enlarging projection 13 that is inserted into the pipe hole 12 of the steel pipe 4 is integrally or integrally protruded from the center of the lower surface 11.

The diameter-expanding projection 13 is composed of an introduction end 14 having a diameter D4 smaller than the inner diameter D3 of the steel pipe 4, and a tapered base 15 gradually increasing in diameter in correspondence with the tapered hole 9.

Place the press jig 5 against the flange portion 2 of the flange member 1,
When the upper surface 8 of the lower mold 6 and the lower surface 11 of the upper mold 10 are clamped and pressed together (arc-fastened (see FIG. 4)), the boss portion 3 of the flange member 1 has its outer circumference formed by the tapered hole 9 of the lower mold 6. The steel pipe 4 is narrowed in the inner diameter direction, and at the same time, the end of the steel pipe 4 is expanded in diameter by the tapered base 15 of the upper die 10.

That is, due to the pressing action described above, the steel pipe 4 end (arrow A) expands in diameter in the outer diameter direction, and at the same time, the portion (arrow B) slightly inward from the end (arrow A) is subjected to the squeezing action of the boss 3. Accordingly, the flange member 1 and the steel pipe 4 are crimped together by a tapered pressure contact surface 16 which is inclined so that the inner circumference of the boss portion 3 and the outer circumference of the end of the steel pipe 4 become larger toward the outside. be done.

The tapered crimping surface 16 is reliably maintained even after the press jig 5 is opened, and has an airtight effect, and since the crimping surface is wide and inclined, it has strong adhesion strength to the flange portion 2 in the end face direction. It becomes like this. Next, FIG. 6 is a front sectional view of a flange member 1a showing another embodiment of the present invention.

The flange member 1a has an annular protrusion 17 formed on a portion of the flange portion 2a near the boss portion 3a, and the protrusion 17 can be formed using a press machine at the same time as the boss portion 3a.

The inner diameter D1 of the boss portion 3a of the flange member 1a is also the same as that of the steel pipe 4.
The lower die 6 and the upper die 10 of the press jig 5 are tightened while the steel pipe is temporarily supported on the end of the steel pipe 4, and the lower die 6 and the upper die 10 of the press jig 5 are tightened. Similar to the example,
The diameter of the end of the steel pipe 4 is expanded by the tapered base 15, and the boss portion 3a of the flange member 1a is narrowed in the radial direction, so that the two are closely fixed. Further, at the same time as the fixing action, the upper surface 8
The protruding ridge 17 is compressed between the lower surface 11 and the lower surface 11, and the inner diameter of the boss portion 3a on the flange surface side is reduced due to the expansion of the ridge due to the pinching.

The outer periphery of the steel pipe 4 end and the boss portion 3a expanded due to the reduction
The outer ends are now more tightly pressed together.

As explained above, according to the method for fixing a flange on a steel pipe of the present invention, the boss portion formed in advance on the flange is deformed by drawing together with the outer periphery of the steel pipe, and when integrating with the steel pipe, the shape of the press jig is It can be easily fixed and integrated by tightening action, and mass production of flanged steel pipes is possible. Further, according to the present invention, the steel pipe and the flange member are closely fixed to each other so that the boss portion formed on the flange member has a relatively wide contact surface, and the diameter of the contact surface becomes larger toward the outside. Since the flange is slanted, the flange has high reliability in terms of fixation strength.

Furthermore, according to the method of the present invention, the protrusions formed in advance on the flange member are expanded by the clamping action of the press jig, and a strong clamping force is generated in the inner diameter direction. The effects of the present invention are great, such as extremely high airtightness and adhesion.

[Brief explanation of the drawing]

The drawings relate to a method for fixing flanges in steel pipes of the present invention,
FIG. 1 is a front sectional view of a flange member showing a first embodiment;
Figure 2 is a front sectional view of the steel pipe, Figure 3 is a front sectional view before mold clamping, Figure 4 is a front sectional view during mold clamping, Figure 5 is a front sectional view of a flanged steel pipe, and Figure 6 is a front sectional view of the steel pipe with a flange. FIG. 7 is a front sectional view of a flange member showing the second embodiment, FIG. 7 is a front sectional view during mold clamping, and FIG. 8 is a front sectional view of a flanged steel pipe. 1, 1a...Flange member, 2, 2a...
...Flange part, 3, 3a...Boss part, 4...
... Steel pipe, 5 ... Press jig, 6- ...
... Lower mold, 7 ... Support hole, 9 ... Tapered hole, 10 ... Upper mold, 13 ... Diameter expansion projection, 15 ... ...Tapered base, 17...Protrusion.

Claims (1)

[Claims] 1. A steel plate is punched into a polygonal or circular annular body using a press device, and at the same time, an annular boss portion is formed by bending the inner hole toward one surface, and the boss portion is attached to the end of the steel pipe. After the boss is inserted in the inner diameter direction by the taper hole in the lower mold of the press jig, which is pressed against the lower and upper surfaces of the flange of the flange member by clamping, the boss part is compressed in the inner diameter direction, and at the same time, the taper base of the upper mold A method for fixing a flange on a steel pipe, which comprises expanding the diameter of the end of the steel pipe, bringing the parts of both members into close contact, and fixing the flange member to one end of the steel pipe. 2. Providing the flange member with an annular uneven strip protruding in the surface direction on the flange portion adjacent to the boss portion, and expanding the uneven strip by the clamping action of the press jig,
2. The method for fixing a flange to a steel pipe according to claim 1, wherein the inner diameter of the boss portion is reduced due to this expansion, thereby increasing airtightness and fixing strength with the steel pipe.