JP2003278965A - Method and device for forming spigot protrusion of pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a welding process without problems upon forming a spigot protrusion of a pipe by welding a spigot under the condition of having a ring split cut once in the circumferential direction fitted on the outside of the spigot. <P>SOLUTION: A weld metal is supplied to an outer circumferential groove 6 of a spigot ring 3 in front of a press roller 2 provided along the rotating direction of a pipe 1 while the pipe 1 fitted on the outside of the spigot ring is made to rotate around the axis and presses the spigot ring 3 from the ring end 13 constituting a split part 12 in the circumferential direction of the spigot ring 3. After the weld metal is supplied in the circumferential direction to the outer circumferential groove 6 accompanying the rotation of the pipe 1, the welding power is reduced to cope with the spigot ring 3 not being able to press due to the pressing roller 2 deviating from an end 14 on the ring 3 of the split part 12. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a pipe insertion protrusion.

[0002]

2. Description of the Related Art As a joint for ductile cast iron pipe, a separation preventing pipe joint or a seismic pipe joint is known which prevents a pair of pipes joined to each other from separating from each other. Further, as such a pipe joint, while forming an insertion port projection on the outer periphery of the insertion port of one of the pipes joined to each other, a lock ring is provided inside the receiving port of the other pipe into which this insertion port is inserted. Put it on,
It is known that the insertion opening projection is caught on the lock ring from the back side of the receiving opening to prevent the receiving opening and the insertion opening from being separated.

A method shown in FIG. 7 is known as a method for forming an insertion port projection on the outer periphery of the insertion port of a cast iron pipe. That is, in FIG. 7, an insertion opening 2 is formed at one end of the ductile cast iron pipe 1, and an insertion ring 3 is externally fitted to and fixed to the insertion opening 2, whereby an insertion opening projection 4 is formed. Is formed. A chamfered portion 5 is formed at the tip of the insertion slot 2. An outer peripheral groove 6 and an outer peripheral tapered surface 7 are formed in the insertion ring 3. Reference numeral 8 denotes a groove bottom portion of the outer peripheral groove 6.

In such a case, when the insertion port projection 4 is formed, the insertion ring 3 is moved by the guiding action of the chamfered part 5 of the insertion port 2 as shown in FIGS. The outer ring taper surface 3 is fitted to the insertion opening 2 and the insertion opening ring 3 is positioned at a distance from the tip of the insertion opening 2.
Position so that it is on the tip side of. Next, as shown in FIG. 3C, the outer peripheral groove 6 is welded to supply the molten metal,
In addition, the heat generated during welding causes the groove bottom portion 8 and the corresponding surface portion of the insertion opening 2 to melt. In FIG. 3C, 9 is the welded portion and 10 is the welded portion. When the welding work is completed, the tip of the insertion opening 2 is tapered corresponding to the outer peripheral tapered surface 7 of the insertion opening 3 as shown in FIG. By forming the tapered surface 11 over the area, the insertion opening protrusion 4 having a desired shape can be formed.

As shown in FIG. 7 (c), when the molten metal is supplied to the outer peripheral groove, while supporting the pipe 1, that is, the insertion port 2 in the horizontal direction and slowly rotating it about its axis,
Using the welding torch, work will be gradually performed along the circumferential direction.

[0006]

Rather than forming the insertion ring 3 into a perfect annular shape and press-fitting it into the pipe 1,
Rather, it is better to fit the pipe in the circumferential direction by expanding it elastically to some extent and fitting it in the external fitting state even if the diameter of the pipe 1 fluctuates within the tolerance range. This is convenient because it can be done.

However, in the case where the structure is divided into one in the circumferential direction as described above, there arises a technical problem that the welding process of the divided portion must be performed without any problem. Therefore, the present invention solves such a problem, and welds to the insertion hole in a state in which a ring divided in the circumferential direction is fitted to the insertion opening, thereby forming an insertion protrusion portion on the pipe. , The purpose is to be able to perform the welding process without problems.

[0008]

In order to achieve this object, the present invention fits a circumferentially-divided insertion ring into an insertion opening of a pipe and supplies molten metal to an outer peripheral groove of the insertion ring. Then, when forming the insertion opening projection by welding the insertion opening ring to the insertion opening, the circumference of the insertion opening ring is rotated while rotating the tube in which the insertion opening ring is fitted around the axis. From one end of the ring that constitutes the divided portion of the direction, while pressing the insertion ring against the insertion opening by the pressing roller, the molten metal is supplied to the outer peripheral groove in front of the pressing roller along the rotation direction of the tube, After the molten metal is supplied to the outer circumferential groove in the circumferential direction due to the rotation, the pressing roller deviates from the other end of the ring in the divided portion and the insertion ring cannot be pressed, so that the welding is performed. Reduce heat input Than it is.

Also, the present invention is a device for forming an insertion protrusion by externally fitting an insertion ring having an outer peripheral groove, which is divided in the circumferential direction, into the insertion opening of a pipe and welding the insertion opening. However, by supplying molten metal to the outer peripheral groove of the insertion opening ring of the tube supported so as to rotate around the axis, a welding torch capable of welding the insertion opening ring and the insertion opening, and rotation of the tube. Provided at a position on the rear side of the welding torch along the direction, and having a pressing roller capable of pressing the portion of the insertion ring in front of which molten metal is supplied to the insertion torch by the welding torch,
The welding torch is supplied with molten metal in a circumferential direction from the ring one end portion that constitutes a circumferentially divided portion of the insertion ring to the outer peripheral groove along with the rotation of the pipe, and then the pressing roller is provided in the divided portion. In response to deviating from the other end of the ring and making it impossible to press the insertion ring,
The heat input amount by the welding can be reduced.

Therefore, according to the present invention, since the pressing roller deviates from the other end of the ring in the divided portion of the insertion ring and the insertion ring cannot be pressed, the heat input amount by welding is reduced. Even if the pressing roller cannot press the heat roller, thermal distortion or the like hardly occurs in the insertion ring, and the welding process can be performed without any problem.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 6, first, an insertion opening ring 3 is fitted onto an insertion opening 2 of a pipe 1. The spout ring 3
Similar to the one shown in FIG. 7, it has an outer peripheral groove 6, an outer peripheral tapered surface 7, and a groove bottom portion 8. Further, as shown in the figure, the insertion ring 3 is formed so as to be divided in the circumferential direction so as to be loosely fitted into the insertion port 2. Reference numeral 12 is a divided portion along the circumferential direction, 13 is one end of the ring of the divided portion 12, and 14 is the other end of the ring of the divided portion 12.

The cast iron pipe 1 having the insertion ring 3 fitted therein is
While being supported in the horizontal direction and being slowly rotated around its axis, the insertion ring 3 is welded to the insertion opening 2 by the method and device for forming a pipe insertion protrusion according to the present invention. It

As shown in FIG. 3, the device for forming a tube insertion protrusion according to the present invention is arranged corresponding to the top of the insertion port 2 of the tube 1 supported in the horizontal direction as described above. The welding torch 21, the first pressing roller 22 provided in the vicinity of the welding torch 21 on the rear side of the welding torch 21 along the rotation direction D of the tube 1, and the rotation direction D of the tube 1.
A position rearward of the first pressing roller 22 along the
That is, the welding torch 21 is more than the first pressing roller 22.
And a second pressing roller 23 arranged at a position away from.

As shown in FIGS. 3 and 4, the first pressing roller 22 hits the outer periphery of the insertion opening ring 3 so that the portion of the insertion opening ring 3 can be pressed toward the insertion opening 1. A portion 27 and an annular protrusion 28 that fits into the outer peripheral groove 6 of the insertion ring 3 without a substantial gap in the axial direction thereof,
It has a large-diameter flange portion 29 that can come into contact with the end surface 15 of the insertion slot 2. Therefore, the first pressing roller 22 is positioned near the welding torch 21 in a state where the portion of the insertion ring 3 which is about to be welded is positioned in the axial direction with respect to the insertion opening 2. It is configured so that it can be pressed against the insertion slot 2.

As shown in FIGS. 3 and 5, the second pressing roller 23 comes into contact with the outer periphery of the insertion ring 3,
A roller portion 30 that can press the portion of the insertion opening ring 3 toward the insertion opening 1 and an annular projection 31 that fits into the outer peripheral groove 6 of the insertion opening ring 3 without a substantial gap in the axial direction thereof. Have As shown in FIG. 2, the second pressing roller 23 is provided, for example, at a position apart from the first pressing roller 22 along the circumferential direction of the tube 1 by about 90 degrees. 32 is a support bracket. This second pressing roller 23
Is capable of pressing the insertion opening ring 3 at the same position as the first pressing roller 22 along the axial direction of the insertion opening 2 at a position spaced from the first pressing roller 22 in the circumferential direction. Is.

The welding torch 21 welds the outer peripheral groove 6 of the insertion opening ring 3 pressed by the insertion opening 2 by the first and second pressing rollers 22 and 23 in this state to supply the molten metal. However, the welded portion 9 and the welded portion 10 can be formed thereby.

Next, a method of forming the pipe insertion projection based on the above-described structure will be described. The cast iron pipe 1 is rotated around its axis in a posture of being supported in the horizontal direction as illustrated. Further, an insertion ring 3 is loosely fitted to the pipe 1 at an appropriate time before the welding work is started by a manual work of an operator. Then, the first pressing roller 22 presses the insertion opening ring 3 at the top of the insertion opening 2 while positioning the insertion opening ring 3 in the axial direction, and the welding torch 21 is pressed.
To the outer peripheral groove 6 of the insertion ring 3. Further, the second pressing roller 23 presses the insertion ring 3 at a position spaced from the first pressing roller 22 in the circumferential direction in a state where the insertion ring 3 is similarly positioned in the axial direction.

Then, in this state, while slowly rotating the pipe 1, starting from the ring one end portion 13 of the insertion ring 3 shown in FIG. 6, as described above, the first and second pressing rollers 22, 23 are formed. While pressing the insertion opening ring 3 against the insertion opening 2, the molten torch 21 supplies molten metal to the outer peripheral groove 6 of the insertion opening 3, and as the pipe 1 rotates, the molten metal is supplied from the ring one end 13 to the outer peripheral groove 6. The molten metal is supplied in the direction to form the welded portion 9 and the welded portion 10.

FIG. 1 shows the situation when the pipe 1 has made almost one revolution after starting the welding starting from the one end 13 of the ring. At this time, the first pressing roller 22 has already deviated from the other end portion 14 of the ring and is positioned corresponding to the space portion of the divided portion 12. On the other hand, the welding torch 21
Has not completed welding to the position of the end point of the other end 14 of the ring. In other words, the other end portion of the ring 14 has to be welded in a state in which it has a free end that is no longer pressed by the first pressing roller 22 in a certain range near the end point of the welding.

At this time, if welding is performed under the same conditions as before, the free end portion of the ring other end portion 14 of the insertion ring 3 is excessively affected by heat, and as shown by a phantom line in FIG. This portion is thermally deformed so as to expand in the radial direction. That is, this portion is thermally deformed so as to float from the insertion slot 2. Therefore, if no measures are taken, the other end portion 14 of the ring is welded to the insertion opening 2 in such a lifted state, and the insertion opening projection is formed higher than the prescribed size at that portion.

Further, when the other end 14 of the ring, which is in the free end state as described above, is welded, the pressing force by the first pressing roller 22 does not exist, so that the outer peripheral groove 6 part is not formed. Attempts to expand by a larger amount than the part. At this time, as shown in FIG. 7, the outer peripheral groove 6 of the insertion ring 3 is not formed in the central portion along the axial center of the insertion ring 3, but the insertion ring 3 is inserted. It is formed at a position where it is separated from the end surface 15 of the insertion slot 1 when it is fitted to the outer wall 2. Therefore, if no measures are taken, the other end portion 1 of the ring is
4 is closer to the outer peripheral groove 6 than the end portion 15 of the insertion slot 2 in FIG.
The portion having the ring has a larger thermal expansion, and the other end 1 of the ring
4 is deformed so that its free end is curved in a direction approaching the end surface 15 of the insertion slot 1.

Therefore, when the first pressing roller 22 deviates from the insertion ring 2 and cannot press the other end 14 of the ring, the heat input by the welding torch 21 is correspondingly reduced. Specifically, the rotation speed of the pipe 1 is increased to increase the welding feed, the wire feed amount in the welding torch 21 is decreased, the welding current in the welding torch 21 is decreased, or a combination thereof is used. Therefore, the amount of heat input is reduced. By doing so, the other end portion 14 of the ring is not heated more than necessary, so that thermal strain is unlikely to occur even without being pressed by the first pressing roller 22, and the occurrence of floating as shown in FIG. It is possible to prevent the occurrence of bending as shown in FIG.

When the welding of the other end portion 14 of the ring is completed in the state where the heat input amount by the welding torch 21 is reduced as described above, thereafter, the ring one end portion 13 and the ring other end portion 14 in the divided portion 12 of the insertion ring 3 are completed. A space will be left between and. At this time, when the pipe 1 is further rotated around the axis while the heat input amount by the welding torch 21 is reduced as described above, the build-up welded portion 33 can be formed in the space as shown in the figure. . As a result, it is possible to form a completely annular insertion-portion protrusion that is free from defects in the circumferential direction.

After all, the range in which the first pressing roller 22 deviates from the insertion ring 2 and cannot press the other end 14 of the ring and the range of the space of the divided portion 12 which follows, that is, FIG. 2B. In the range R shown, the welding torch 21
By reducing the amount of heat input by the method, it is possible to form the insertion protrusion satisfactorily in a state where there is no rising or bending and the space of the dividing portion 12 is filled by the overlay welding and there is no defect. In addition, before the first pressing roller 22 deviates from the insertion opening ring 2, that is, from the time when the first pressing roller 22 is still pressing the insertion opening ring 2 and the pressing state has not ended, preliminary It is also possible to reduce the amount of heat input.

[0025]

As described above, according to the present invention, the insertion ring which is divided in the circumferential direction is fitted into the insertion opening of the pipe, and the molten metal is supplied to the outer peripheral groove of the insertion ring. When the mouth ring is welded to the insertion opening from one end of the ring in the divided portion in the circumferential direction to form the insertion protrusion, the pressing roller can deviate from the other end of the ring in the divided portion to press the insertion ring. Corresponding to the disappearance, the amount of heat input by the welding is reduced, so that even if the pressing roller cannot press it, thermal distortion or the like is unlikely to occur in the insertion ring,
The welding process can be performed without problems.

[Brief description of drawings]

FIG. 1 is a diagram showing a method of forming an insertion protrusion of a pipe according to an embodiment of the present invention.

FIG. 2 is another view showing the same forming method.

FIG. 3 is a cross-sectional view of essential parts showing a schematic configuration of a device for forming a pipe insertion protrusion according to the embodiment of the present invention.

FIG. 4 is an enlarged side view of the first pressing roller in FIG.

5 is an enlarged side view of a second pressing roller in FIG.

FIG. 6 is a diagram showing a state in which an insertion ring is externally fitted to a cast iron pipe.

FIG. 7 is a view showing a conventional method for forming an insertion protrusion of a pipe.

[Explanation of symbols]

1 Ductile cast iron pipe 2 spout 3 mouth ring 12 divisions 13 One end of ring 14 other end of ring 21 welding torch 22 First pressing roller

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoji Kochio             2-16-1 Sakaemachi, Funabashi City, Chiba Stock Association             Kubota Funabashi factory (72) Inventor Mitsuru Saito             2-16-1 Sakaemachi, Funabashi City, Chiba Stock Association             Kubota Funabashi factory

Claims (2)

[Claims] Claims: 1. Inserting a circumferentially divided insertion ring into the insertion opening of a pipe, supplying molten metal to the outer peripheral groove of the insertion ring, and welding the insertion ring to the insertion opening. When the insertion protrusion is formed by, while rotating the tube in which the insertion ring is fitted around the axial center, from the one end of the ring that constitutes the circumferential divided portion of the insertion ring, While pressing the mouth ring against the insertion opening with the pressing roller, the molten metal is supplied to the outer peripheral groove in front of the pressing roller along the rotation direction of the pipe, and the molten metal is supplied to the outer peripheral groove in the circumferential direction as the pipe rotates. After that, in response to the pressing roller deviating from the other end of the ring in the divided portion and the insertion ring being unable to be pressed, the heat input amount by the welding is reduced, Method of forming protrusion. 2. An apparatus for forming an insertion protrusion by externally fitting an insertion ring, which has a circumferential groove and is divided in the circumferential direction, into the insertion opening of a pipe and welds the insertion ring to the insertion opening. , A welding torch capable of welding the insertion ring and the insertion opening by supplying molten metal to the outer peripheral groove of the insertion opening ring of the tube supported so as to rotate about the axis, and the rotation direction of the tube And a pressing roller that is provided at a position rearward of the welding torch and that is capable of pressing the portion of the front insertion ring to which molten metal is supplied by the welding torch to the insertion port. After the molten metal is supplied in the circumferential direction to the outer peripheral groove along with the rotation of the pipe from one end of the ring that constitutes the circumferentially divided portion of the insertion ring, the pressing roller causes the other end of the ring in the divided portion. Departing from the section, the insertion ring can be pressed A device for forming a pipe insertion projection, which is configured so as to be able to reduce the amount of heat input by the welding in response to the loss of heat.