JP2009168075A - Pipe joint structure, and pipe connection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe joint structure, capable of achieving strong pull resistance, and excellent seal performance. <P>SOLUTION: The structure is provided with an outer engagement cylinder part 2 of metal, having a hole part 3 to which a pipe P to be connected is inserted. A recessed circumferential groove 5 is formed on an outer circumferential surface of the outer engagement cylinder part 2. A groove bottom surface 5a of the recessed circumferential groove 5 is set for a pressure receiving surface to receive the pressure of a diameter shrinkage work member. The pipe P is inserted into the hole part 3 corresponding to the groove bottom surface 5a. The groove bottom surface 5a of the recessed circumferential groove 5 formed on the outer circumferential surface of the outside engagement cylinder part 2 is pushed by the pressure of the diameter shrinkage work member to press it till its diameter shrinks with the pipe P, thereby they are connected to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pipe joint structure and a pipe connection method.

  Conventionally, flare joints have been widely used as pipe joints for refrigerant pipes in air conditioners. That is, it is a structure in which a pipe flared at the tip is connected to the male member by a cap nut and connected to a male member having a tip diameter-reduced taper portion and a male screw portion (see, for example, Patent Document 1).

However, the above-described flare joint has a drawback that torque management is difficult, and the internal fluid (refrigerant) leaks due to abnormal deformation of the flare machining part due to excessive torque or insufficient tightening due to excessive torque. there were. Moreover, when it was used for a long period, there existed a fault that an internal fluid leaked from a flare process part.
Japanese Patent Laid-Open No. 11-23105

  The problem to be solved is that torque control is difficult when a flare-processed pipe is connected, and internal fluid is likely to leak. In addition, when repairing, it takes time and effort to flare the new pipe.

  Therefore, the pipe joint structure according to the present invention includes a metal outer fitting cylinder portion having a hole portion into which the connected pipe is inserted, and a concave groove is formed on the outer peripheral surface of the outer fitting cylinder portion. The groove bottom surface of the groove is a pressure-receiving surface that receives the pressing force of the diameter-reducing work tool, and a reduced-diameter plastic deformation portion is formed on the inner peripheral surface of the hole corresponding to the groove bottom surface so as to be integrated with the corresponding portion of the pipe It is formed by being reduced in diameter and deformed and connected.

In addition, a seal groove is formed on the inner peripheral surface of the hole corresponding to the groove bottom surface, and a seal material is fitted into the seal groove.
In a region other than the position corresponding to the groove bottom surface, a seal groove is formed on the inner peripheral surface of the hole, and a seal material is fitted in the seal groove.
In addition, an independent annular ridge is formed on the inner peripheral surface of the hole corresponding to the groove bottom surface in a state before the reduced diameter plastic deformation.

  And the pipe connection method according to the present invention includes inserting a pipe into a metal outer fitting cylinder portion having a concave circumferential groove on the outer peripheral surface, and then forming a groove bottom surface corresponding to the concave circumferential groove of the outer fitting cylinder portion. In this method, the reduced diameter working tool is connected to the corresponding portion of the pipe by being subjected to a reduced diameter plastic deformation integrally.

  According to the present invention, it is only necessary to insert the pipe to be connected while it is cut, and processing such as flare processing becomes unnecessary. And it exhibits excellent sealing performance over a long period of time against a fluid such as a refrigerant. Further, the resistance to pulling out the pipe is extremely large.

1 and 2 show an embodiment of the present invention, FIG. 2 shows a state during connection, and FIG. 1 shows a connection (completed) state.
P is a connected pipe made of a metal such as copper, and 2 is a metal external fitting cylinder portion such as brass, copper or bronze having a hole portion 3 in which the connected pipe P is inserted as indicated by an arrow A. It is.
The external fitting cylinder part 2 includes a tapered male screw 19 (see FIGS. 3 and 4), a screw hole and other structures (for example, an outer cylinder part 20 into which another pipe 13 is inserted and brazed as shown in FIG. 1). The pipe joint body has a part of the pipe joint main body, or one part (part) of various pipe joints (not shown). In addition, L shows an axial center, and FIG. 1, FIG. 2 shows only a part above this axial center L in a cross section.

Then, (two) concave circumferential grooves 5 and 5 are formed on the outer peripheral surface of the outer fitting cylinder portion 2, and the groove bottom surface 5 a of the concave circumferential groove 5 serves as a pressing force (arrow F in FIG. 1). Reference) is the pressure receiving surface. Although not shown in the drawings, the diameter reducing work tool is a work tool with a handle having, for example, three rolling rollers, and at least one of the rollers is screwed or hydraulically or the like. By pressing strongly in the diameter reducing direction, the groove bottom thin portion 6 is reduced in diameter by plastic deformation while rolling the groove bottom surface 5a of the concave circumferential groove 5, and the pipe inserted as shown in FIG. The pipe P is pressed against the outer peripheral surface of the P, and the pipe P is slightly plastically deformed with a reduced diameter.
In other words, the diameter-reduced plastic deformation portion 7 is formed (as a circumferential ridge) on the inner peripheral surface of the hole 3 corresponding to the groove bottom surface 5a, and the diameter-reduced plastic deformation is integrated with the corresponding portion of the insertion pipe P. Then, the outer fitting cylinder part 2 and the pipe P are connected (connected).

By the way, shallow circumferential groove portions 8, 9, 10 are formed in the hole portion 3 of the outer fitting cylindrical portion 2, so that both axial end positions of the groove bottom thin portion 6 corresponding to the concave circumferential groove 5 do not contact the pipe P. In addition, the “escape” is formed. That is, as can be seen from FIG. 2, the shallow peripheral groove portions 8, 9, 10 allow the inner peripheral surface of the hole portion 3 corresponding to the groove bottom surfaces 5 a, 5 a to have a low independent circular ring before the reduced diameter plastic deformation. The ridges 18, 18 are formed.
Thus, the reduced diameter pressing force indicated by the arrow F is concentratedly applied to the groove bottom thin portion 6 so that the reduced diameter plastic deformation portion 7 is easily formed. Then, in the pipe P, a concave circumferential plastic deformation portion 11 corresponding to the reduced diameter plastic deformation portion 7 is formed.

As described above, according to the pipe connecting method according to the present invention, the pipe P is disposed inside the metal externally fitted tube portion 2 having one or two (or more) concave grooves 5 and 5 on the outer peripheral surface. Next, the groove bottom surface 5a corresponding to the concave circumferential grooves 5 and 5 of the outer fitting cylindrical portion 2 is shrunk into a unit with the corresponding portion of the pipe P by a diameter reducing work tool. This is a method of connecting by deforming the diameter plastically, and can be quickly and easily, reliably, stably and firmly integrated.
In FIGS. 1 and 2, reference numeral 13 denotes a (other) pipe to which the pipe P is connected via the pipe joint 1 having the pipe joint structure according to the present invention. Is a pipe 13 on the air conditioner side, which is inserted into the hole 14 of the outer cylindrical portion 20 on the other end side of the pipe joint 1 and fixed (connected) by brazing 15.

Next, FIG. 3 and FIG. 4 show other embodiments, FIG. 4 shows a state during connection, and FIG. 3 shows a connection (completed) state.
The points different from FIGS. 1 and 2 will be described with emphasis. A seal groove 16 is formed on the inner peripheral surface of the hole 3 corresponding to the groove bottom surface 5 a of the concave circumferential groove 5. A sealing material 17 such as a ring is fitted. In other words, when the seal groove 16 having a rectangular cross section is formed on the inner peripheral surface of the lower independent annular ridge 18 and connected as shown in FIGS. 4 to 3, the reduced diameter plastic deformation portion 7 and the outer peripheral surface of the pipe P are connected. In the pressure contact state, the sealing material 17 further reliably improves the sealing performance.

  3 and FIG. 4, the case where the pipe joint 1 has the taper male screw 19 is illustrated. Thus, in the present invention, even if the outer fitting cylinder portion 2 is a part of the pipe joint 1 having the taper male screw 19, the outer cylinder to be brazed 15 as shown in FIGS. The pipe fitting 1 having a portion 20 may be partly configured, and furthermore, the external fitting cylinder part 2 may be formed on one part or part of various pipe fittings having a cap nut or other connecting mechanism. Be free.

  3 and FIG. 4, the same reference numerals as those in FIG. 1 and FIG. Moreover, since the pipe connection method is the same, description thereof is omitted. In addition, although the sealing material 17 made of an O-ring is illustrated, it may be freely formed in other shapes and structures such as U packing, V packing, and square packing.

Next, FIG. 5 and FIG. 6 show another embodiment, FIG. 6 shows a state during connection, and FIG. 5 shows a connection (completed) state.
In the embodiment shown in FIGS. 5 and 6, the seal groove 16, which is formed on the inner peripheral surface of the hole portion 3 in a region (axial center position) other than the position corresponding to the groove bottom surface 5 a of the concave groove 5. 16 is formed, and a seal material 17 is fitted into the seal groove 16. 5 and 6 exemplify the case in which the seal grooves 16 and 16 are formed as slightly larger rectangular grooves and the seal material 17 made of U packing is used. As the sealing material 17, an O-ring similar to that shown in FIGS. 3 and 4 or a material having a shape or structure such as a square packing or a V packing may be used.
5 and 6 show the case where the seal grooves 16 and 16 are formed in the axially inner portion of the concave circumferential grooves 5 and 5.

In the embodiment shown in FIGS. 5 and 6, a plurality of triangular ridges 21 are formed on the inner peripheral surface of the hole 3 corresponding to the groove bottom surface 5a.
When the pipe P is inserted in the direction of arrow A in FIG. 6 and the groove bottom surface 5a is strongly pressed by the diameter reducing work tool as indicated by arrow F in FIG. 5, the groove bottom thin portion 6 is plastically deformed in the diameter reducing direction. The triangular mountain-shaped protrusion 21 bites into the outer peripheral surface of the pipe P, and the pipe P is connected by forming a concave circumferential plastic deformation portion 11.

  In this way, the triangular mountain-shaped protrusion 21 bites in, so that not only the pulling strength is further improved, but also the local surface pressure is increased, so that the sealing performance is further improved (improved). In addition, it is more preferable for the protrusion 21 to be a triangular mountain shape inclined inward of the pipe joint 1 in terms of an improvement in pulling force and a sealing performance, or in addition to the triangular mountain shape, Maruyama type etc. is free. In addition, it is also preferable to apply such protrusion 21 to the above-described embodiment shown in FIGS. 1 to 4 (not shown).

5 and 6, the same reference numerals as those in FIGS. 1 to 4 have the same configuration and the same pipe connection method, and thus the duplicated description is omitted.
In addition, this invention is applicable not only to the case of using for new piping (work) but repair, piping replacement, etc.

  As described above, the present invention includes a metal outer fitting cylinder portion 2 having a hole portion 3 into which the connected pipe P is inserted, and a concave circumferential groove 5 is formed on the outer circumferential surface of the outer fitting cylinder portion 2. The groove bottom surface 5a of the concave circumferential groove 5 serves as a pressure receiving surface that receives the pressing force of the diameter reducing work tool, and the diameter-reduced plastic deformation portion 7 is formed on the inner peripheral surface of the hole 3 corresponding to the groove bottom surface 5a. Since the pipe P and the external fitting cylinder portion 2 are connected to each other by a reduced diameter plastic deformation integrally with the corresponding portion of the pipe P, the sealing performance can be improved at the same time. There is an advantage that there is no fear of pulling out or fluid leakage over a long period of use. Troublesome processing such as flare processing or the like is not necessary on the pipe P side, and it is only necessary to cut and insert on the surface orthogonal to the axis.

Further, a seal groove 16 is formed on the inner peripheral surface of the hole portion 3 corresponding to the groove bottom surface 5a, and a seal material 17 is fitted in the seal groove 16, so that it is at the most strongly pressed portion. Thus, the sealing material 17 works effectively and can exhibit a further excellent sealing performance.
Further, in a region other than the position corresponding to the groove bottom surface 5a, the seal groove 16 is formed on the inner peripheral surface of the hole 3, and the seal material 17 is fitted in the seal groove 16. The sealing material 17 always exhibits stable sealing performance.
In addition, since the independent annular protrusion 18 is formed on the inner peripheral surface of the hole 3 corresponding to the groove bottom surface 5a in a state before the reduced diameter plastic deformation, The portion of the ridge 18 is pressed against the outer peripheral surface of the pipe P with a strong contact surface pressure, the pulling force is increased, and the sealing performance is also improved.

  Moreover, the pipe 2 is inserted in the metal external fitting cylinder part 2 which has the concave periphery groove | channel 5 in an outer peripheral surface, and the groove bottom face 5a corresponding to the concave periphery groove | channel 5 of the said external fitting cylinder part 2 is diameter-reduced next. Since it is a pipe connection method in which the work tool is connected to the corresponding part of the pipe P by reducing the diameter of the pipe P in an integrated manner, it exhibits excellent workability and can be operated easily and quickly.

It is a principal part expanded sectional view which shows embodiment of this invention. It is a principal part expanded sectional view of the state in the middle of a connection operation | work. It is a principal part expanded sectional view which shows other embodiment. It is a principal part expanded sectional view of the state in the middle of a connection operation | work. It is a principal part expanded sectional view which shows another embodiment. It is a principal part expanded sectional view of the state in the middle of a connection operation | work.

Explanation of symbols

2 external fitting 3 hole portion 5 concave circumferential groove 5a groove bottom surface 7 reduced diameter plastic deformation portion
16 Seal groove
17 Sealing material
18 Independent ring ridge P pipe

Claims (5)

  It has a metal outer fitting cylinder part (2) having a hole (3) into which the connected pipe (P) is inserted, and a concave circumferential groove (5) is formed on the outer peripheral surface of the outer fitting cylinder part (2). The groove bottom surface (5a) of the concave circumferential groove (5) serves as a pressure receiving surface that receives the pressing force of the diameter reducing work tool, and the groove (5a) is contracted to the inner peripheral surface of the hole (3) corresponding to the groove bottom surface (5a). A pipe joint structure in which a radial plastic deformation portion (7) is formed, and is connected to a corresponding portion of the pipe (P) by being subjected to a reduction plastic deformation integrally.   A seal groove (16) is formed on the inner peripheral surface of the hole (3) corresponding to the groove bottom surface (5a), and a seal material (17) is fitted in the seal groove (16). Item 1. The pipe joint structure according to Item 1.   In a region other than the position corresponding to the groove bottom surface (5a), a seal groove (16) is formed on the inner peripheral surface of the hole (3), and a seal material (17 The pipe joint structure according to claim 1 or 2, wherein:   The independent annular ridge (18) is formed on the inner peripheral surface of the hole (3) corresponding to the groove bottom surface (5a) in a state before the reduced diameter plastic deformation. The pipe joint structure described.   A pipe (P) is inserted into a metal outer fitting cylinder (2) having a concave groove (5) on the outer peripheral surface, and then corresponds to the concave groove (5) of the outer fitting cylinder (2). A pipe connecting method, wherein the bottom surface of the groove (5a) to be connected is deformed and plastically deformed integrally with the corresponding portion of the pipe (P) by a diameter reducing work tool.

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