JP3267475B2 - Method of forming the insertion protrusion of cast iron pipe - 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 of forming a ring-shaped insertion projection for preventing the connection from coming off at the outer periphery of the front end of the insertion at the connection of a cast iron pipe.

[0002]

2. Description of the Related Art As shown in FIG. 3, a stopper ring 3 'made of steel or ductile cast iron or the like is generally fixed to a connection portion of a cast iron tube 1, particularly an outer peripheral surface 2a of an insertion opening 2. By doing so, an annular insertion projection 3 is formed. A groove 5 is formed on the inner peripheral surface of the receiving port 4 on the mating side of the connection side of the cast iron tube 1, and a lock ring 6 having a circumferentially split shape is formed in the groove 5 via a centering rubber ring 7. The lock ring 6 and the insertion projection 3 are engaged with each other, so that the connection portions of the cast iron pipe 1 are not separated from each other. Reference numeral 8 in FIG. 3 denotes a rubber ring disposed between the groove 9 near the opening end of the receiving port 4 and the outer peripheral surface 2a of the insertion port 2.

Conventionally, the stopper ring 3 'is integrally fixed to the insertion port 2 of the cast iron pipe 1 as described below to form the insertion projection 3. As shown in FIG. 4A, the stopper ring 3 ′ forming the insertion projection 3 has an inner diameter slightly smaller than the outer diameter of the cast iron pipe 1 when no external force is applied. ing. The stopper ring 3 ′ has a groove 3 b formed on the inner peripheral surface 3 of the stopper ring 3 ′.
The wire 11 made of a brazing material is fitted into the groove 3b in such a manner as to be formed at a position near the tip of the insertion opening in FIG. Then, a flux (not shown) for a brazing material is applied in advance to the inner peripheral surface 3a of the stopper ring 3 'and the portion of the insertion opening 2 of the cast iron pipe 1 where the stopper ring 3' is joined.

[0004] Next, as shown in FIG. 4 (b), the stopper ring 3 ′ on which the wire 11 is disposed is connected to one end 3 c of the stopper ring 3 ′ which is located at the front end side of the insertion opening. By pressing it toward the side, it is externally fitted in the insertion opening outer peripheral surface 2a in a press-fit state.

Thereafter, the cast iron tube 1 is heated to melt the wire 11 in the groove 3b of the stopper ring 3 '. As a heating and melting method in this case, as shown in FIG. 5, the cast iron pipe 1 is disposed in a posture where the pipe axis x is horizontal, and the pipe axis x
Is performed by heating only from the inner peripheral surface side of the insertion opening of the cast iron tube 1 while rotating around the center. As a result, FIG.
(C), the stopper ring 3 'and the cast iron pipe 1
Is joined with a brazing material 11 ′ to form an insertion protrusion 3 on the outer periphery of the insertion hole 2.

Finally, as shown in FIG. 4 (d), the outer peripheral surface of the front end of the insertion port 2 and the front end portion of the insertion projection 3 are tapered again so that the taper becomes thinner toward the front end. Surface 12 is formed. Here, when performing this taper processing, a portion including the groove 3b of the stopper ring 3 'is scraped off, and finally the stopper ring 3' and the insertion opening 2 are joined without the groove 3b. An insertion projection 3 is formed.

According to this method, since the groove 3b is formed in the inner peripheral surface 3a of the stopper ring 3 'and the wire 11 made of brazing material is disposed in the groove 3b, a sufficient amount of the wire 11 is provided. Can be secured. Further, as shown in FIG. 4D, the joint between the stopper ring 3 'and the insertion opening 2 of the cast iron tube 1 is finally joined without the groove 3b of the stopper ring 3'. Therefore, a larger joint area between the insertion projection 3 and the insertion port 2 of the cast iron pipe 1 can be secured, and the joining force can be increased.

[0008] Thereafter, the rubber ring 8, the centering rubber ring 7, and the lock ring 6 are inserted into the insertion port 4 provided in advance.
At this time, the rubber ring 8 and the lock ring 6 are guided by the tapered surface 12 of the insertion opening 2 to expand the diameter, and the insertion of the insertion opening 2 into the receiving opening 4 is allowed.

[0009]

However, in the conventional method for forming an opening in a cast iron pipe, the heating and melting work of the brazing material 11 'is performed by heating only from the inner peripheral surface side of the opening of the cast iron pipe 1. Therefore, the temperature of the backup ring 7 side is lower than that of the insertion port 2 side at the junction between the insertion port 2 and the backup ring 7, causing a temperature difference between them and heating in a short time. Was prone to uneven temperature. Therefore, in this case, it is difficult to stably spread the brazing material 11 ′, and there is a possibility that a sufficient joining force may not be obtained.

[0010] The present invention solves the above-mentioned problems, and a molten iron filler metal can be favorably spread between a stopper ring and an insertion opening of a cast iron pipe so that a sufficient joining force can be obtained. It is an object of the present invention to provide a method for forming an insertion projection.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, the present invention is to form a groove on the inner peripheral surface of a stopper ring which finally becomes an insertion projection of a cast iron pipe, and to form a groove in the groove of the stopper ring. A brazing material is provided, and a stopper ring provided with the brazing material is externally fitted to an outer peripheral surface of the insertion port at a connection portion where the insertion port and the receiving port of the cast iron pipe are connected, and includes a brazing material disposing portion. A method for forming an insertion projection of a cast iron tube in which a stopper ring and an insertion opening of a cast iron pipe are brazed and joined to form an insertion projection for preventing a connection portion from being detached by heating a portion to melt a brazing material. When heating the portion including the brazing material disposing portion, depending on the thickness of the stopper ring and the thickness of the insertion opening of the cast iron pipe, from the outer peripheral side of the stopper ring with a heating amount proportional to each thickness. And from the inner peripheral side of the insertion opening of the cast iron tube.

According to the above method, heating is performed in both directions from the outer peripheral side of the stopper ring and the inner peripheral side of the insertion opening of the cast iron tube, and the amount of heating is reduced by the thickness of the stopper ring and the thickness of the insertion opening of the cast iron tube. Since the temperature was set proportionally, the temperature on the stopper ring side and the temperature on the insertion side at the point where the brazing material was joined became equal, and there was no temperature difference, and the brazing material could be heated uniformly. Heating and melting operations can be performed in a short time.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The components having the same functions as those in the related art are denoted by the same reference numerals.

As shown in FIG. 2A, the inner diameter D1 of the stopper ring 3 'forming the insertion projection 3 is slightly smaller than the outer diameter D2 of the cast iron tube 1 when no external force is applied. It is made to fit. The stopper ring 3 ′ is disposed in such a manner that the groove 3 b is formed at a position near the tip of the insertion opening on the inner peripheral surface of the stopper ring 3 ′, and the wire 11 made of brazing material is fitted into the groove 3 b. . Then, a flux (not shown) for a brazing material is applied in advance to the inner peripheral surface 3a of the stopper ring 3 'and the portion of the insertion opening 2 of the cast iron pipe 1 where the stopper ring 3' is joined. Further, the outer periphery of a portion of the stopper ring 3 'located on the front end side of the insertion opening is tapered to a position near the groove portion 3b, and the thickness of the stopper ring 3' from the tapered surface 3d to the groove portion 3b is reduced to make it thinner. A portion 3e is formed.

Next, as shown in FIGS. 2 (b) and 2 (c), the stopper ring 3 'on which the wire 11 is disposed is connected to the one end 3 of the stopper ring 3' at the front end of the insertion opening.
By pressing from c to the back side of the insertion hole, it is externally fitted in the insertion outer peripheral surface 2a in a press-fit state. In this case, in order to fit the stopper ring 3 ′ to the outer peripheral surface 2 a of the insertion opening 2, one end portion 3 c disposed on the distal end side of the insertion opening of the stopper ring 3 ′
Is pressed toward the inner side of the insertion opening, the pressing point is closer to the inner circumference than the thin portion 3e of the stopper ring 3 ', so that the thin portion 3e of the stopper ring 3' is used as a bending point and one end of the stopper ring 3 '. The 3c side is deformed inward. This allows
Since the opening side of the groove 3b of the stopper ring 3 'is narrowed, the wire 11 is securely held in the groove 3b of the stopper ring 3', and the stopper ring 3 'is prevented from dropping out of the groove 3b.

Thereafter, the cast iron tube 1 is heated to melt the wire 11 in the groove 3b of the stopper ring 3 '. As a heating and melting method in this case, as shown in FIG. 1, the pipe axis x is tilted so that the tip end side of the insertion opening of the cast iron pipe 1, that is, the side on which the wire 11 is disposed is upward. While rotating not only from the inner peripheral side of the cast iron tube 1 but also from the outer peripheral side of the stopper ring 3 '. At this time, the inclination angle θ is desirably 5 degrees to 60 degrees. In addition, the heating amount at this time is set to a heating amount proportional to the thickness of the stopper ring 3 ′ and the thickness of the insertion opening 2 of the cast iron pipe 1 according to the thickness. That is, when the thickness of the stopper ring 3 'is 3 mm and the thickness of the insertion opening 2 of the cast iron pipe 1 is 6 mm, the stopper ring 3'
Is heated so that the amount of heating from the outer peripheral surface 3f and the amount of heating from the inner peripheral surface 2c of the insertion opening 2 become 1: 2.

As a result, the molten brazing material 11 ′ is located in the gap between the outer peripheral surface 2 a of the insertion opening 2 and the inner peripheral surface 3 a of the stopper ring 3 ′ on the inner side of the insertion opening 2 which is below the groove 3 b. At the same time, the temperature on the stopper ring 3 'side and the temperature on the insertion port 2 side at the portion to be joined with the brazing material 11' are equalized and the temperature difference disappears, and the brazing material 11 ' Heating and melting can be performed uniformly in a short time, and a sufficient joining force can be obtained between the insertion port 2 and the insertion projection 3. In this way, as shown in FIG. 2D, the stopper ring 3 'and the insertion port 2 of the cast iron pipe 1 are joined by the brazing material 11', and the insertion projection 3 is formed on the outer periphery of the insertion port 2. Form.

Finally, as shown in FIG. 2E, the outer peripheral surface of the front end of the insertion port 2 and the front end portion of the insertion projection 3 are tapered again so that the front end becomes thinner. Surface 12 is formed. Here, when performing this taper processing, a portion including the groove 3b of the stopper ring 3 'is scraped off, and finally the stopper ring 3' and the insertion opening 2 are joined without the groove 3b. An insertion projection 3 is formed.

The conventional method of heating only from the inner peripheral side of the cast iron pipe 1 and the method of the present invention of heating from the inner peripheral side of the cast iron pipe 1 and the outer peripheral side of the stopper ring 3 'according to the respective thicknesses. To compare 2.4 mm wire 11 mm
93mm diameter, 2.5mm thick, with silver brazing made of
The stopper ring 3 ′ having a width of 32.4 mm was compared with a case where the stopper ring 3 ′ was brazed to the cast iron tube 1. As a result, the conventional method requires about 40 seconds as a heating time,
In many cases, the spread of 1 ′ was poor, the detachment prevention force was unstable, and only about 0.2 Dtf was obtained.
In the method of the present invention, the spread of the brazing material 11 ′ is stable, and the detachment preventing force is also stable and 0.45 Dtf, which is a value that can sufficiently withstand use, is obtained while the heating time is about 30 seconds.

It is to be noted that the present invention may be applied in a horizontal posture without inclining the cast iron tube 1 as in the above embodiment. It goes without saying that the size of the cast iron tube 1 and the stopper ring 3 'and the type of the brazing material 10 are not limited to those described above.

[0021]

As described above, according to the method for forming an insertion projection of a cast iron pipe of the present invention, heating is performed from both directions from the outer peripheral side of the stopper ring and the inner peripheral side of the insertion port of the cast iron pipe.
By setting the amount of heating to an amount proportional to the thickness of the stopper ring and the thickness of the insertion hole of the cast iron tube, the temperature of the stopper ring side and the temperature of the insertion side at the place where the brazing material is joined are used. And the temperature difference disappears, the brazing material can be heated uniformly, and the heating and melting work can be performed in a short time, while the detachment prevention force by the insertion projection can be increased and the reliability can be improved. Performance can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a heating and melting step in a method for forming an insertion projection of a cast iron pipe according to an embodiment of the present invention.

FIGS. 2A to 2E are cross-sectional views showing respective steps in a method for forming an insertion projection of a cast iron pipe according to an embodiment of the present invention.

FIG. 3 is a sectional view of a joint portion of a cast iron pipe.

FIGS. 4A to 4D are cross-sectional views showing respective steps in a conventional method for forming an insertion projection of a cast iron pipe.

FIG. 5 is a cross-sectional view showing a heating and melting step in a conventional method for forming an insertion projection of a cast iron tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cast iron pipe 2 Insert 2a Outer peripheral surface 2c Inner peripheral surface 3 Insert protrusion 3 'Stopper ring 3a Inner peripheral surface 3b Groove 3f Outer peripheral surface 11 Wire 11' Brazing material

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI F16L 21/08 F16L 21/08 B (56) References JP-A-49-76752 (JP, A) JP-A-7-27266 ( JP, A) Japanese Patent No. 2778909 (JP, B2) Japanese Utility Model No. 45-9975 (JP, Y1) Japanese Utility Model No. 46-21147 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 1/18 B23K 1/19 C21D 9/08 F16L 13/08 F16L 13/12 F16L 21/00 F16L 21/02 F16L 21/08

Claims (1)

(57) [Claims] A groove is formed in an inner peripheral surface of a stopper ring which finally becomes an insertion projection of a cast iron pipe, a brazing material is provided in the groove of the stopper ring, and a stopper provided with the brazing material is provided. The stopper ring is formed by externally fitting the ring to the outer peripheral surface of the insertion port at the connection portion where the insertion port and the receiving port of the cast iron tube are connected, and heating the portion including the brazing material disposing portion to melt the brazing material. A method for forming an insertion projection of a cast iron pipe, in which an insertion projection for preventing connection portion detachment is formed by brazing and joining an insertion opening of a cast iron pipe to a portion including a brazing material disposing portion. In this case, according to the thickness of the stopper ring and the thickness of the insertion opening of the cast iron tube, heating is performed from the outer peripheral side of the stopper ring and the inner peripheral side of the insertion opening of the cast iron tube with a heating amount proportional to each thickness. A method for forming an insertion projection of a cast iron tube.