JP3323094B2 - Method of forming protrusion of tube insertion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a projection of a tube opening.

[0002]

2. Description of the Related Art As one type of pipe joint, there is a slip-on type pipe joint. This slip-on type pipe fitting is configured such that a receiving material and a receiving material can be joined by inserting a sealing material into the receiving material while compressing the sealing material into the receiving material. ing. As a slip-on type pipe joint provided with a detachment prevention function, a detachment prevention pipe joint having a configuration shown in FIG. 4 has been proposed.

That is, in FIG. 4, a receiving port 2 is formed at an end of one of the cast iron pipes 1 joined to each other.
An annular rubber sealing material 4 is disposed in the sealing material receiving groove 3 on the inner periphery of the receiving port 2, and a lock ring receiving groove 5 is formed on the back side of the sealing material receiving groove 3. 5 is provided with a lock ring 6 divided in a circumferential direction. Outer peripheral side of lock ring 6 and lock ring receiving groove 5
A holding rubber ring 7 for holding the lock ring 6 in a centered state is disposed between the lock ring 6 and the inner peripheral side of the lock ring 6, for example.

On the outer periphery of the distal end of the insertion port 9 of the other cast iron tube 8, a projection 10 that can engage with the lock ring 6 from the back side of the reception port is formed. A tapered surface 11 serving as a guide when inserting the insertion port 9 into the receiving port 2 in which the sealing material 4 and the lock ring 6 are accommodated is formed on the outer periphery of the front end of the insertion port 9 including the projection 10. Have been.

FIGS. 5 to 7 show a conventional method for forming the projection 10 having the tapered surface 11 as described above. That is, first, the metal ring 16 is attached to the outer periphery of the insertion opening 9. The ring 16 is formed, for example, in a circumferentially split manner, and is tapered toward the distal end of the insertion port 9, and a direction parallel to the axis of the insertion port 9. And an outer peripheral surface 18. An outer peripheral groove 19 having a rectangular cross section is formed in the outer peripheral surface 18 in the circumferential direction. 20 is the groove bottom.

Next, this ring 16 is attached to the positioning roller 2.
1 presses against the outer surface of the insertion opening 9. The positioning roller 21 has a flange portion 22, and the side surface 23 of the flange portion 22 is configured to be in contact with the distal end surface 24 of the insertion opening 9. The positioning roller 21 is provided on the outer peripheral surface 19
Has a roller portion 25 that is in contact with
An annular projection 26 having a rectangular cross section is formed to fit into the outer peripheral groove 19 of the ring 16. The annular projection 26 is formed such that its outer periphery does not hit the groove bottom 20. The positioning roller 21 further has a tapered portion 27 that contacts the outer peripheral tapered surface 17 of the ring 16. The tapered portion 27 and the flange portion 22 are mutually connected and integrated by a shaft portion 28. The shaft portion 28 is formed with a diameter such that it does not hit the outer surface of the insertion opening 9.

Therefore, when the ring 16 is pressed by the positioning roller 21 as shown in the figure, the side surface 23 of the flange portion 22 of the positioning roller 21
The ring 16 is fitted in the outer circumferential groove 19 of the ring 16 in a state where the ring 16 is in contact with the Pressing will prevent lifting.

Therefore, as shown in FIG. 6, while slowly inserting the insertion opening 9 around the axis, the positioning roller 2 is rotated.
The molten metal 30 is poured into the outer peripheral groove 19 by the welding torch 29 immediately behind the first roller portion 25, and the groove bottom 20 and the surface of the insertion opening 9 are both melted.
As shown in (1), the ring 16 is positioned in the axial direction and is welded to the insertion port 9 over the entire circumference in a state of being in contact with the outer peripheral surface of the insertion port 9. 31 is a welding bead.

Since the weld bead 31 has a raised portion 32 outwardly of the ring 16, the outer peripheral surface 19 of the ring 16 is formed.
The raised portion 32 is scraped off in order to smooth the surface. Finally, the opening 9 is connected to the outer peripheral tapered surface 17 of the ring 16.
To form a tapered surface 11.

[0010]

However, since the ring 16 has a predetermined dimensional tolerance, depending on the dimensional variation within this tolerance, the outer peripheral tapered surface 17 of the ring 16 and the positioning roller may be particularly arranged as shown in FIG. There is a possibility that a gap 33 is formed between the tapered portion 27 and the outer peripheral tapered surface 17 and the ring 16 cannot be sufficiently pressed against the insertion opening 9 at the outer peripheral tapered surface 17. Then, as shown in FIG.
Is welded to the opening 9, the tip of the ring 16 rises at the tapered surface 17, and there is a problem that a gap 34 is formed between the tip of the ring 16 and the opening 9.

It is an object of the present invention to solve such a problem and to prevent the ring from rising from the insertion port after welding even when the ring dimensions vary within tolerance. And

[0012]

In order to achieve this object, the present invention provides a method in which a ring having a larger inner diameter at the center than at both ends is mounted on the outer periphery of an insertion port of a pipe, and the ring is fixed by a roller. This ring is welded to the opening while pressing the opening.

[0013] In this case, since the ring has a larger inner diameter at the center than at both ends, when the ring is pressed against the insertion opening by the roller, the surface pressure at both ends increases. Therefore, even if the ring has a dimensional variation within the tolerance after welding, both ends of the ring are in close contact with the insertion opening, and the floating is prevented.

Further, the present invention is to apply a spatter adhesion preventing liquid to a roller. This prevents spatter from adhering to the roller without providing a cover or the like between the welding torch and the roller.

Further, the ring of the present invention is formed such that the inner diameter gradually increases from both ends in the axial direction toward the center. With such a configuration, the inside diameter of both ends of the ring is surely smaller than the inside diameter of the other part on the center side, and therefore, when this ring is pressed against the insertion opening by the roller,
Even if the ring has a dimensional variation within the tolerance, the surface pressure at both ends increases and the ring comes into close contact with the opening, thereby preventing the ring from rising after welding.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. 1 to 3 in which the same members as those shown in FIGS. Will be described.

1 to 3, reference numeral 9 denotes a cast iron tube 8;
, 21 is a positioning roller, 29 is a welding torch,
These are the same configurations as those shown in FIGS. Reference numeral 41 denotes a ring according to the present invention, which is formed to be tightly divided in the circumferential direction similarly to the ring shown in FIGS. 5 to 7 and has an outer periphery tapering toward the distal end of the insertion opening 9. Tapered surface 42 and outer peripheral surface 43 in a direction parallel to the axis of insertion opening 9
And An outer peripheral groove 44 having a rectangular cross section is formed in the outer peripheral surface 43 in the circumferential direction. 45 is the bottom of the groove.

As shown in detail in FIG.
The central portion, that is, the groove bottom portion 45 and the periphery thereof are formed to have a larger inner diameter than the both end portions, that is, the one end portion 46 and the other end portion 47 in the axial direction. Reference numeral 48 denotes the maximum inner diameter portion formed at a position corresponding to the groove bottom 45. Specifically, on the inner circumference of the ring 41, a first inclined surface 49 whose inner diameter gradually increases from one end 46 toward the maximum inner diameter portion 48, and gradually from the other end 47 toward the maximum inner diameter portion 48. And a second inclined surface 50 having a larger inner diameter. D is a distance along the radial direction from one end 46 and the other end 47 to the maximum inner diameter portion 48.

As shown in the figure, the length L1 along the axial direction from the maximum inner diameter portion 48 corresponding to the groove bottom portion 45 to one end portion 46 on the outer peripheral tapered surface 42 side is equal to the length L1 from the maximum inner diameter portion 48 to the other end portion. It is formed so as to be longer than the length L2 along the axial direction up to 47. This is to make the cross-sectional areas of both sides of the outer circumferential groove 19 in the cross section of the ring 41, that is, the heat capacities substantially equal, so that unnecessary stress is not applied to the ring 16 when welding is performed using the outer circumferential groove 44. That's why.

As shown in FIG. 3, a separating funnel 53 storing a spatter adhesion preventing liquid 52 is disposed above the positioning roller 21. As the spatter adhesion preventing liquid 52, for example, “PROTECA M” manufactured by Matsumoto Kikai Co., Ltd.
And so on. In addition, when the spatter adhesion preventing liquid generally used for the welding base material is used here, when this liquid adheres to the ring 41,
It is not preferable because the welding of No. 1 cannot be performed.

In such a configuration, when a projection is formed on the outer periphery of the insertion opening 9, a ring 41 is formed on the outer periphery of the insertion opening 9.
Is mounted, and is pressed by the roller 21 in a positioning state. Then, since the inner diameter of the center portion, that is, the maximum inner diameter portion 48 of the ring 41 is formed larger than the both end portions, that is, the one end portion 46 and the other end portion 47, the surfaces of the one end portion 46 and the other end portion 47 are pressed when pressed. The pressure is higher than in other parts. Therefore, even if the ring 41 has a dimensional variation within the tolerance, the welding can be completed in a state where the one end 46 and the other end 47 are in close contact with the outer surface of the insertion opening 9, and the floating thereof is prevented. Can be.

Specifically, for example, a metal ring 41
When the thickness in the radial direction is several mm, the distance D is 0.3
The first and second inclined surfaces 49 and 50 are formed so as to have a diameter of 0.1 mm, and the ring 41 is welded while being pressed by the positioning roller 21, so that the floating of the ring 41 can be suppressed to within 0.1 mm.

At this time, as shown in FIG.
By dropping the spatter adhesion preventing liquid 52 onto the positioning roller 21 from 3, it is possible to prevent a situation in which spatter during welding adheres to the roller 21 and the ring 41 cannot be welded thereafter.

In order to prevent the spatter from adhering to the positioning roller 21, it is possible to arrange a shielding cover between the roller 21 and the welding torch 29. However, in this case, when the spatter gradually accumulates on the cover and the solidification increases, this is welded to the weld bead portion, the welding heat is transmitted, the cover is melted, and a gap is formed in the melted portion. There is a possibility that an accident that spatter is scattered through and adheres to the roller 21 may occur.

On the other hand, when the spatter preventing liquid 52 is dropped on the roller 21 as in the present invention, the above-mentioned problem caused by using the cover can be solved without using the above-mentioned cover. And the roller 21
It is possible to reliably prevent spatter from adhering to the surface. The drop amount is, for example, about 1 cc every 10 seconds is sufficient.

[0026]

As described above, according to the present invention, a ring having a larger inner diameter at the center than at both ends is attached to the outer periphery of the insertion port of the pipe, and this ring is pressed against the insertion port by a roller. However, when the ring is welded to the opening, the surface pressure of both ends increases when the ring is pressed against the opening with a roller, so even if the ring has a dimensional variation within the tolerance, the ring is welded. Can be made to be in a state of being in close contact with the insertion opening, so that the floating can be prevented.

Further, according to the present invention, since the spatter adhesion preventing liquid is applied to the roller, it is possible to prevent the adhesion of spatter to the roller without providing a cover or the like between the welding torch and the roller.

Further, according to the present invention, since the ring is formed so that the inner diameter gradually increases from both ends in the axial direction toward the center, the inner diameter of both ends of the ring is changed to other parts on the center side. It is possible to increase the surface pressure at both ends of the ring when the ring is pressed against the opening even if the ring has a dimensional variation within the tolerance. Can be brought into close contact with the insertion opening, so that it is possible to reliably prevent lifting after welding.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a configuration for describing a method for forming an insertion projection according to an embodiment of the present invention.

FIG. 2 is a diagram showing the ring in FIG. 1 in detail.

FIG. 3 is a cross-sectional view of the portion shown in FIG.

FIG. 4 is a diagram illustrating a pipe joint using a pipe with an insertion ring.

FIG. 5 is a cross-sectional view of a main part of a configuration for explaining a conventional method of forming an insertion projection.

FIG. 6 is a side sectional view of a portion shown in FIG. 5;

FIG. 7 is a longitudinal sectional view of a welding completed portion in FIG.

FIG. 8 is a cross-sectional view of the configuration of FIG. 5 in the case where there are variations in ring dimensions.

FIG. 9 is a longitudinal sectional view of the welding completion state in the case of FIG. 8;

[Explanation of symbols]

 9 Insertion 41 Ring 46 One end 47 Other end 48 Maximum inner diameter 52 Spatter adhesion preventing liquid

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-185028 (JP, A) JP-A-10-26271 (JP, A) JP-A 9-184582 (JP, A) JP-A 7-185 155937 (JP, A) JP-A-7-91577 (JP, A) JP-A-5-231572 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16L 21/00-21 / 08

Claims (3)

(57) [Claims] 1. A ring formed with a larger inner diameter at the center than at both ends is attached to the outer circumference of the insertion port of the pipe, and the ring is welded to the insertion port while pressing the ring against the insertion port with a roller. A method for forming a projection of an insertion opening of a pipe, characterized in that: 2. The method according to claim 1, wherein a spatter adhesion preventing liquid is applied to the roller. 3. A ring for forming a protruding portion at the insertion port by welding to the outer periphery of the insertion port of the pipe, and the inner diameter is gradually increased from both ends in the axial direction toward the center. A ring for forming a projection of an insertion opening of a tube, characterized in that the ring is formed so as to be large.