JP3989272B2 - Method and apparatus for forming tube insertion protrusion - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for forming a tube insertion protrusion.
[0002]
[Prior art]
As a joint of a ductile cast iron pipe, a detachment prevention pipe joint or a seismic pipe joint that prevents a pair of pipes joined to each other from being separated is known. In addition, as such a pipe joint, an insertion protrusion is formed on the outer periphery of the insertion opening of one pipe joined to each other, and a lock ring is provided inside the receiving opening of the other pipe into which the insertion opening is inserted. It is known that the insertion port is prevented from being detached from the insertion port by attaching the insertion port protrusion to the lock ring from the back side of the reception port.
[0003]
As a technique for forming the insertion protrusion on the outer periphery of the insertion hole of the cast iron pipe, a method as shown in FIG. 7 is known. That is, in FIG. 7, an insertion port 2 is formed at one end of the ductile cast iron tube 1, and the insertion ring 3 is fitted and fixed to the insertion port 2, thereby fixing the insertion projection 4. 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.
[0004]
In such a case, when forming the insertion projection 4, the insertion ring 3 is inserted into the insertion port 2 by the guiding action of the chamfered portion 5 of the insertion port 2 as shown in FIGS. The insertion ring 3 is positioned at a distance from the distal end of the insertion opening 2, and the outer peripheral tapered surface 7 is positioned at the distal end side of the insertion opening 2. Next, as shown in FIG. 3C, welding is performed on the outer peripheral groove 6 to supply molten metal, and the bottom of the groove 8 and the surface portion of the insertion slot 2 corresponding to the groove are melted by heat during welding. . In FIG. 9C, 9 is the welded portion and 10 is the penetration portion. When the welding operation is completed, the tip of the insertion port 2 is tapered corresponding to the outer peripheral tapered surface 7 of the insertion ring 3 as shown in FIG. By forming the tapered surface 11 over the entire length, the insertion projection 4 having a required shape can be formed.
[0005]
When supplying molten metal to the outer peripheral groove as shown in FIG. 7 (c), a welding torch is used while supporting the tube 1 or the insertion port 2 in the horizontal direction and slowly rotating around its axis. Thus, the work is gradually performed along the circumferential direction.
[0006]
[Problems to be solved by the invention]
Rather than forming the insertion ring 3 into a complete annular shape and press-fitting it into the tube 1, it is better to divide it into the tube in a state where it is divided into one portion in the circumferential direction and elastically expanded to some extent. This is advantageous because the tube 1 can be mounted in an externally fitted state without any trouble even when the diameter of the tube 1 fluctuates within a tolerance range.
[0007]
However, in the case where the structure is divided into one piece in the circumferential direction as described above, there arises a technical problem that the divided portion must be welded without any problem.
Therefore, the present invention solves such a problem and welds the ring with a circumferentially divided ring to the insertion port to form the insertion protrusion on the tube. The purpose is to enable the welding process to be performed without problems.
[0008]
[Means for Solving the Problems]
In order to achieve this object, the present invention is configured such that a circumferentially divided insertion ring is fitted to the insertion opening of the pipe, molten metal is supplied to the outer circumferential groove of the insertion ring, and the insertion ring is inserted. When forming the insertion protrusion by welding to the mouth, one end of the ring constituting the circumferential division of the insertion ring while rotating the tube with the insertion ring fitted around the axis The molten metal is supplied to the outer circumferential groove in front of the pressing roller along the rotation direction of the tube while the insertion ring is pressed against the insertion port by the pressing roller. In response to the fact that the pressing roller deviates from the other end of the ring in the divided portion and the insertion ring cannot be pressed after the molten metal is supplied, the amount of heat input by the welding is reduced.
[0009]
Further, the present invention provides an apparatus for forming an insertion protrusion by fitting a circumferentially divided insertion ring having an outer peripheral groove to a tube insertion opening and welding to the insertion opening. By supplying molten metal to the outer peripheral groove of the tube insertion ring supported so as to rotate around the center, a welding torch capable of welding the insertion ring and the insertion port, and along the rotation direction of the tube A pressing roller provided at a position on the rear side of the welding torch and capable of pressing a portion of the insertion ring in front of the molten metal supplied by the welding torch to the insertion port, the welding torch, After the molten metal is supplied in the circumferential direction to the outer circumferential groove with the rotation of the tube from the ring one end constituting the circumferential dividing portion in the insertion ring, the pressing roller is moved from the other end of the ring in the dividing portion. Deviate and can not press the insertion ring It becomes possible to correspond to, which is constituted to be able to reduce the amount of heat input by the welding.
[0010]
Therefore, according to the present invention, in response to the pressing roller deviating from the other end of the ring in the split portion of the insertion ring and being unable to press the insertion ring, the amount of heat input due to welding is reduced. Even if the pressing cannot be performed, thermal distortion or the like hardly occurs in the insertion ring, and the welding process can be performed without any problem.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 6, the insertion ring 3 is first fitted onto the insertion opening 2 of the tube 1. The insertion ring 3 has an outer circumferential groove 6, an outer circumferential tapered surface 7, and a groove bottom portion 8, similarly to the one shown in FIG. 7. Further, as shown in the figure, the insertion ring 3 is formed in one piece in the circumferential direction and is configured to be loosely fitted to the insertion opening 2. Reference numeral 12 denotes a divided portion along the circumferential direction, 13 denotes one end of the ring in the divided portion 12, and 14 denotes the other end of the ring in the divided portion 12.
[0012]
The cast iron pipe 1 to which the insertion ring 3 is fitted is supported in the horizontal direction, and is slowly rotated around its axis, while the pipe insertion protrusion forming method according to the present invention is provided. The insertion ring 3 is welded to the insertion opening 2 by the device.
[0013]
As shown in FIG. 3, the tube insertion protrusion forming apparatus according to the present invention is a welding torch 21 arranged corresponding to the top of the insertion port 2 of the tube 1 supported in the horizontal direction as described above. A first pressing roller 22 provided in the immediate 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 a first along the rotation direction D of the tube 1. A second pressing roller 23 disposed at a position rearward of the pressing roller 22, that is, at a position farther from the welding torch 21 than the first pressing roller 22.
[0014]
As shown in FIG. 3 and FIG. 4, the first pressing roller 22 contacts the outer periphery of the insertion ring 3, so that the roller portion 27 that can press the portion of the insertion ring 3 toward the insertion port 1. 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, and a large-diameter flange portion 29 that can contact the end face 15 of the insertion opening 2. ing. Therefore, the first pressing roller 22 is positioned near the welding torch 21 in a state where the portion of the insertion ring 3 that is about to be welded is positioned in the axial direction with respect to the insertion opening 2. It is comprised so that it can press to the insertion port 2. FIG.
[0015]
As shown in FIGS. 3 and 5, the second pressing roller 23 hits the outer periphery of the insertion ring 3, so that the roller portion 30 capable of pressing the portion of the insertion ring 3 toward the insertion port 1, An annular protrusion 31 that fits into the outer circumferential groove 6 of the insertion ring 3 without a substantial gap in the axial direction is provided. As shown in FIG. 2, the second pressing roller 23 is provided, for example, at a position about 90 degrees away from the first pressing roller 22 along the circumferential direction of the tube 1. Reference numeral 32 denotes a support bracket. The second pressing roller 23 is located at the same position as the first pressing roller 22 along the axial direction of the insertion slot 2 at a position spaced from the first pressing roller 22 in the circumferential direction. Can be pressed.
[0016]
The welding torch 21 supplies the molten metal by welding the outer circumferential groove 6 of the insertion ring 3 pressed against the insertion opening 2 in the positioning state by the first and second pressing rollers 22 and 23 as described above. Thus, the welded portion 9 and the penetration portion 10 can be formed.
[0017]
Next, a method of forming the tube insertion protrusion based on the above configuration will be described. The cast iron pipe 1 is rotated around its axis in a posture supported in the horizontal direction as shown in the figure. Further, the insertion ring 3 is loosely fitted onto the pipe 1 by an operator's manual work or the like at an appropriate time before the welding work is started. The first pressing roller 22 presses the insertion ring 3 at the top of the insertion port 2 in the axially positioned state, and causes the welding torch 21 to face the outer circumferential groove 6 of the insertion ring 3. Further, the second pressing roller 23 is pressed at a position spaced from the first pressing roller 22 in the circumferential direction in the same manner while the insertion ring 3 is positioned in the axial direction.
[0018]
Then, in this state, the tube 1 is slowly rotated, and the first and second pressing rollers 22 and 23 are used for insertion as described above, starting from the ring one end 13 of the insertion ring 3 shown in FIG. While pressing the ring 3 against the insertion slot 2, molten metal is supplied to the outer circumferential groove 6 of the insertion ring 3 by the welding torch 21, and melts in the circumferential direction from the ring one end 13 with respect to the outer circumferential groove 6 as the tube 1 rotates. Metal is supplied to form the welded portion 9 and the melted portion 10.
[0019]
FIG. 1 shows a situation in which the tube 1 is rotated almost once after welding is started with the ring one end 13 as a starting point. At this time, the first pressing roller 22 has already deviated from the ring other end portion 14 and is positioned corresponding to the space portion of the dividing portion 12. On the other hand, the welding torch 21 has not yet completed welding to the position of the end point of the ring other end portion 14. That is, at the other end 14 of the ring, in a certain range in the vicinity of the end point of the welding, the welding must be performed with a free end that is no longer pressed by the first pressing roller 22.
[0020]
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 this portion is shown by a virtual line in FIG. Thermally deforms to spread in the radial direction. That is, this portion is thermally deformed so as to float from the insertion opening 2. Therefore, if no measures are taken, the ring other end portion 14 is welded to the insertion port 2 in the state of being lifted in this way, and the insertion port protrusion is formed higher than a prescribed dimension at that portion.
[0021]
Further, when welding is performed on the ring other end portion 14 in a state where it is a free end as described above, since the pressing force by the first pressing roller 22 does not exist, the portion of the outer peripheral groove 6 is more than the other portion. Also tries to expand greatly. 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 axis of the insertion ring 3, but the insertion ring 3 is inserted into the insertion ring 3. 2 is formed at a position where it will be separated from the end face 15 of the insertion slot 1 when fitted to 2. Therefore, if no measures are taken, the portion having the outer peripheral groove 6 is closer to the end portion 15 of the insertion opening 2 at the other end portion 14 of the ring than the portion near the end surface 15 of the insertion opening 2 as indicated by a virtual line in FIG. The ring other end portion 14 is deformed so as to be bent in a direction in which the free end approaches the end face 15 of the insertion opening 1 due to a large thermal expansion.
[0022]
Therefore, when the first pressing roller 22 deviates from the insertion ring 2 and cannot press the other end 14 of the ring, the amount of heat input by the welding torch 21 is reduced accordingly. Specifically, the rotational speed of the tube 1 is increased to increase the welding feed, the amount of wire feed in the welding torch 21 is reduced, the welding current in the welding torch 21 is reduced, or these are combined. This will reduce the heat input. By doing so, the other end 14 of the ring is not heated more than necessary, and therefore thermal distortion is unlikely to occur even if there is no pressing by the first pressing roller 22, and the occurrence of lifting as shown in FIG. It is possible to prevent the occurrence of bending as shown in FIG.
[0023]
When the welding of the ring other end portion 14 is completed in a state where the heat input by the welding torch 21 is reduced in this way, the ring end portion 13 and the ring other end portion 14 in the split portion 12 of the insertion ring 3 are thereafter Space will be left behind. At this time, when the pipe 1 is further rotated around the axial center in a state where the heat input by the welding torch 21 is reduced as described above, the build-up weld 33 can be formed in the space as shown in the figure. . As a result, it is possible to form a completely annular insertion protrusion having no defect over the circumferential direction.
[0024]
Eventually, 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 space range of the subsequent divided portion 12, that is, the range R shown in FIG. In this case, by reducing the amount of heat input by the welding torch 21, there is no lifting or bending, and the space of the divided portion 12 is filled by overlay welding, so that the insertion protrusion is satisfactorily formed. can do. Before the first pressing roller 22 deviates from the insertion ring 2, that is, from the point in time when the first pressing roller 22 has not yet pressed the insertion ring 2 and the pressing state has not ended. It is also possible to reduce the heat input.
[0025]
【The invention's effect】
As described above, according to the present invention, the insertion ring divided in the circumferential direction is fitted to the insertion opening of the pipe, molten metal is supplied to the outer circumferential groove of the insertion ring, and the insertion ring is inserted in the circumferential direction. This corresponds to the fact that when the insertion protrusion is formed by welding one end of the ring in the split part to the insertion opening, the pressing roller deviates from the other end of the ring in the division part and the insertion ring cannot be pressed. In addition, since the amount of heat input by the welding is reduced, even if pressing by the pressing roller cannot be performed, thermal distortion or the like hardly occurs in the insertion ring, and the welding process can be performed without any problem.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing a method for forming a tube insertion protrusion according to an embodiment of the present invention.
FIG. 2 is another view showing the forming method.
FIG. 3 is a cross-sectional view of a main part showing a schematic configuration of a tube insertion protrusion forming apparatus according to an embodiment of the present invention.
4 is an enlarged side view of a first pressing roller in FIG. 3. FIG.
FIG. 5 is an enlarged side view of a second pressing roller in FIG. 3;
FIG. 6 is a view showing a state where an insertion ring is fitted onto a cast iron pipe.
FIG. 7 is a diagram showing a conventional method for forming a tube insertion protrusion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ductile cast iron pipe 2 Insert 3 Insert port 12 Dividing part 13 Ring one end part 14 Ring other end part 21 Welding torch 22 First press roller

Claims (2)

Inserting the circumferentially split slot into the inlet of the tube, supplying molten metal to the outer peripheral groove of the slot, and welding the slot to the slot When the tube with the insertion ring fitted is rotated around the axis, the insertion ring is pressed from one end of the ring constituting the circumferential division of the insertion ring. The molten metal is supplied to the outer peripheral groove in front of the pressing roller along the rotation direction of the tube while being pressed by the insertion port, and the molten metal is supplied in the circumferential direction to the outer peripheral groove as the tube rotates. A method for forming an insertion protrusion of a tube, characterized in that the amount of heat input by welding is reduced in response to a roller deviating from the other end of the ring in the divided portion and being unable to press the insertion ring. . A device for forming an insertion protrusion by fitting a circumferentially divided insertion ring having an outer circumferential groove to the insertion opening of a pipe and welding to the insertion opening. A welding torch capable of welding the insertion ring and the insertion port by supplying molten metal to the outer peripheral groove of the insertion ring of the tube supported to rotate, and a welding torch along the rotation direction of the tube A pressing roller that is provided at a position on the rear side and capable of pressing a portion of the insertion ring in front of the molten metal supplied by the welding torch to the insertion port, and the welding torch includes the insertion port After supplying molten metal in the circumferential direction from one end of the ring constituting the circumferential division of the ring to the outer circumferential groove as the tube rotates, the pressing roller deviates from the other end of the ring in the division. The insertion ring cannot be pressed. In response to the formation of the spigot projection of the tube, characterized in that it is configured to be able to reduce the amount of heat input by the welding apparatus.

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