KR20220143024A - pipe joint structure - Google Patents

Abstract

In order to provide a pipe joint structure with excellent sealing performance, high pull-out resistance, and long lifespan by responding to large temperature fluctuations of the fluid to be sealed, the joint body 40 and cap nuts 15 and 15 are provided. , The two to-be-connected pipes (P, P) connected to each other have a distal end diameter expansion pipe portion 5 formed over a predetermined axial dimension from the distal end surface. Beyond the tapered stepped portion 10 of the pipe P, a closed round annular ring 25 is fitted outside with respect to the tip diameter expansion tube portion 5, and is formed in a protruding shape at the end of the joint body 40 It is connected by applying a clamping force so that it may press-contact with the connected cylinder part 41 which has been formed.

Description

pipe joint structure

The present invention relates to a pipe joint structure, and more particularly, to a pipe joint structure for connecting pipes to each other.

Conventionally, the flare joint shown in FIG. 16 is widely known. Generally, this flared joint was formed by plastically processing the flared part f at the edge part of the pipe P with a work tool (jig), as shown in FIG. It is pressed against the tapered part (a) of the flare joint body (h) and tightened with the cap nut (n), and the taper surface (t) of the cap nut (n) is inserted into the tapered part (a) of the flare joint body (h) and pressed. , is a configuration that secures sealing properties by mutual pressure welding of metal surfaces (see, for example, Patent Document 1). When forming the flaring part f using a dedicated jig (working tool) at the end of the pipe P for connection at the job site, due to large plastic deformation to a tapered shape, the flaring part f ) is likely to cause cracks in the small-diameter corner portion f1. In particular, when the material of the pipe P is made of Al, the crack occurrence rate is high. Moreover, there existed a problem, such as being easy to generate|occur|produce the fluctuation|variation of quality by the flaring process in a work site (whether the pipe P is Cu or Al).

Then, the pipe joint structure of the structure as shown in FIG. 14 and FIG. 15 was proposed (refer patent document 2).

Japanese Patent Laid-Open No. 2005-42858 Japanese Patent Laid-Open No. 2010-270846

The pipe joint structure shown in Figs. 14 and 15 has a flare joint body 82 and a cap nut 83, and has a pull-out preventing member 81 therein. Although there is an excellent point that it can also be omitted, a very ultra-precise, pull-out preventing member 81 having the claw 80 was required. Therefore, the problem that production is difficult and becomes high cost remains. In addition, when rotational torque is applied to the pipe (P), a spiral groove is formed by the claw (80) and the pipe is pulled out in some cases.

Moreover, in the pipe joint structure of FIG. 14, FIG. 15, sealing materials, such as the (plural) O-rings 84 and 85, are required. This rubber sealing material for O-rings 84 and 85 and the like is difficult to withstand a large temperature change of -50 DEG C to +130 DEG C when the operating temperature is used, and problems remain in terms of durability and sealing properties.

Therefore, the present invention solves such a problem, it is possible to omit ultra-precision parts, and it is easy to manufacture, so that it is possible to achieve cost reduction, and the union type tube joint structure is compact and can perform connection work stably and easily. aims to provide In particular, it is another object to provide a pipe joint structure that sufficiently withstands severe temperature changes of the fluid to be sealed, has a long life, and connects suitable (union-type) pipes to each other.

Therefore, the present invention is provided with a flare joint body having a male screw portion and a tapered tip diameter reduction on each side in the axial direction, and a cap nut having a female screw portion screwed to the male screw portion, and the two to-be-connected pipes connected to each other are A tip diameter-extended pipe portion is formed over a predetermined axial dimension from the tip surface, and a tapered stepped portion is formed at the boundary between the tip-diameter expanded tube portion and the basic diameter tube portion, and is interpolated into the tip diameter expanded tube portion of the pipe. A connecting tube portion and an in-core having a sloped surface abutting against the tapered end diameter reduction tapered portion are provided, and by screwing the cap nut into the flare joint body, through the tapered stepped portion of the pipe, the tip diameter expansion tube portion A closed circular ring-shaped ring fitted from the outside is installed inside the cap nut, and the diameter-reducing biasing force of the ring in the radial inward direction is used to connect the diameter-expanded pipe portion at the tip of the pipe and the connecting tube portion of the in-core. a tapered portion for reducing the diameter of the tip of the flare joint body by transmitting the axial force accompanying the screwing of the cap nut to the flare joint body to the in-core through the ring while maintaining the sealed state; It is comprised so that the pressure-contact sealing state with the inclined surface of an in-core may be maintained.

Moreover, on the outer peripheral surface of the connection cylinder part of the said in-core, the independent small protrusion trough of a plurality of triangular thru|or conical cross-section is formed.

Further, the present invention is provided with a joint body in which a male screw portion, a stepped portion, and a pipe connecting tube portion are sequentially formed on each of both sides in the axial direction, and two cap nuts each having a female screw portion screwed to the male screw portion, each of which is connected to each other. In the two to-be-connected pipes to be connected, a distal end diameter-extended pipe portion is formed over a predetermined axial dimension from the distal end surface, and a tapered stepped portion is formed at the boundary between the distal end diameter-extended pipe portion and the basic diameter pipe portion, and the joint body In a state in which the pipe connecting tube portion of the pipe is inserted into the diameter-extended pipe portion at the tip end of the pipe, by screwing the cap nut into the joint body, it is fitted from the outside through the tapered stepped portion of the pipe to the tip-diameter expansion tube portion A closed ring-shaped ring is installed inside the cap nut, and the diameter-reducing biasing force in the radial inward direction of the ring causes the diameter-expanding pipe at the tip of the pipe and the pipe connection barrel of the joint body. It is designed to maintain a sealed state.

Moreover, on the outer peripheral surface of the pipe connection cylinder part projecting from the said joint main body, the several independent small protrusion troughs of triangular or conical cross section are formed.

Moreover, the sealing material for sealing was abbreviate|omitted completely, and all component parts were made from metal.

Moreover, when the thickness dimension of the said closed annular ring is set to T ₂₅ and the thickness dimension of the said pipe is set to T _p , the dimension was set so that Formula (1) might be satisfied.

1.0·T _p ≤T ₂₅ ≤2.5·T _p (Equation 1)

ADVANTAGE OF THE INVENTION According to this invention, it can manufacture comparatively easily by omitting an ultra-precision part, and, furthermore, can provide strong pulling-out resistance to a pipe. Rubber sealing materials such as O-rings can be omitted, so that it can withstand temperature changes from cryogenic to ultra-high temperatures—for example, -70°C to +150°C———and sufficiently increases the pull-out resistance of the pipe. can keep

Even if it is necessary to pre-process the pipe end with the diameter extension of the distal end, by using the work tool (jig) that has been conventionally used for brazing, it can be processed simply and reliably without requiring skill. Due to the presence of this distal end diameter expansion pipe portion, the inner diameter dimension of the flow passage hole becomes equal to the inner diameter dimension of the pipe itself, and an increase in the fluid passage resistance can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the state during a connection operation|work which shows 1 Embodiment of this invention.
Fig. 2 is an enlarged view of the main part of Fig. 1;
3 is a cross-sectional view showing a state in the middle of a subsequent connection.
Fig. 4 is a cross-sectional view of an essential part showing a connection completion state;
Fig. 5 is an overall cross-sectional view showing a connection completion state.
6 is a cross-sectional view of a state during a connection operation showing another embodiment of the present invention.
7 is a cross-sectional view of the joint body.
Fig. 8 is a cross-sectional view showing a state in the middle of a subsequent connection.
Fig. 9 is a cross-sectional view showing a connection completion state;
Fig. 10 is a cross-sectional view of a connected state showing another embodiment.
11 is a cross-sectional view for explaining the main parts of the disassembled state.
12 is a cross-sectional view for explaining a main part of a tool for forming a distal end diameter expansion pipe portion and a diameter expansion method.
13 is a cross-sectional view for explaining a brazing operation that has been carried out from a long time ago to the present, and a brazed pipe end.
Fig. 14 shows a conventional example, and is a cross-sectional view of a state in the middle of a connection operation.
Fig. 15 is a cross-sectional view of a connected state showing a conventional example.
16 is a cross-sectional view showing another conventional example.

(Form for implementing the invention)

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

In the first embodiment of the present invention shown in Figs. 1 to 5 , the two to-be-connected pipes P and P connected to each other have a distal end diameter from the distal end face 3 to a predetermined axial dimension L ₅ . An expanded tube portion 5 is formed.

A tapered stepped portion 10 is formed at the boundary between the distal end diameter-expanded pipe portion 5 and the basic diameter pipe portion 6 having the original basic diameter D ₀ of the pipe.

Reference numeral 20 denotes a flare joint body, which has a male threaded portion 20A and a tip diameter reduced taper portion 20B in a symmetrical left-right shape, and corresponds to a flared pipe joint stipulated in JIS B 8607, the flare shown in FIG. It is the same as that of the joint body (h).

Reference numeral 15 denotes a cap nut, and has a female screw portion 15A screwed to the male screw portion 20A of the flare joint body 20 .

A large-diameter female threaded portion 15A, a medium-diameter portion 15C, and a tip-side small-diameter portion 15F are sequentially formed in the hole portion 16 of the cap nut 15 from the base end to the tip end (refer to Fig. 2). .

As described above, the pipe joint structure according to the present invention includes a flare joint body 20 having a male threaded portion 20A and a tip diameter reduced tapered portion 20B, and a female threaded portion screwed to the male threaded portion 20A ( 15A) with a pair (two) of cap nuts 15, 15.

Reference numeral 30 denotes an in-core internally held in the cap nut 15 as shown in Fig. 4 in the connected state, and the in-core 30 is interpolated into the distal end diameter expansion pipe portion 5 of the pipe P. A connecting tube portion 31 and a sloped surface 32 abutting against the diameter-reduced tapered portion 20B at the tip of the joint body 20 are provided. Further, as shown in Figs. 1 and 5, the two in-cores 30 and 30 are arranged in a symmetrical left-right shape with the flare joint body 20 interposed therebetween.

More specifically, the in-core 30 has a tube hole 33 along the axial center, and the inclined surface 32 is formed on the proximal side of the tube hole 33, and has a diameter expansion tapered shape in the base end direction. , it is also preferable to have a slightly convex surface shape (convex round shape). Moreover, the in-core 30 is a thick large diameter part 34 whose base end part has a larger diameter than the connection cylinder part 31, and between this thick large diameter part 34 and the connection cylinder part 31 (small diameter). , the stepped portion 35 is formed (see FIG. 2).

Moreover, on the outer peripheral surface of the connection cylinder part 31 of the in-core 30, the several independent small protrusion tank 36 of a plurality of triangular or conical cross-sections are formed.

Further, reference numeral 25 denotes a ring in the form of a closed round annular shape, and consists of a short cylindrical body. As shown in Figs. 1 and 2, the ring 25 is fitted from the outside in a loosely fitted state before the forming processing of the distal end diameter expansion pipe portion 5 with respect to the pipe P, and thereafter (described later). 12), the ring 25 collides with the tapered stepped part 10, and does not deviate toward the tip side of the pipe P (in the left direction of FIG. 2). does not

2 to 3 , when the cap nut 15 is lightly moved leftward (holding it by hand), the ring 25 is fitted to the middle diameter portion 15C of the cap nut 15 . That is, the cap nut 15 has an inner flange portion 17 at its tip position (a small diameter portion 15F is formed on the inner peripheral surface of the inner flange portion 17), and The inner surface 17A of the axial orthogonal surface shape and the front end surface of the said ring 25 contact|abut (refer FIG. 3, FIG. 4, FIG. 5).

2 to 3, when the cap nut 15 is brought close to the joint body 20, and then the cap nut 15 is screwed into the male thread portion 20A of the joint body 20, the cap nut The inner ring 25 of (15) is the inner surface 17A of the inner flange portion 17, and while being pressed in the inward direction of the shaft, it moves in the direction of the tip of the sharpened pipe, and is a tapered stepped portion of the pipe P. (10) abuts.

The inner diameter dimension of this ring 25 is set smaller than the outer diameter dimension of the free state of the distal end diameter expansion pipe part 5 of the pipe P. As shown in FIG. As a result, when the cap nut 15 is continuously turned, the ring 25 passes through the tapered stepped portion 10 of the pipe P as shown in Figs. (5) is fitted from the outside, and a large force (tightening force) is applied in the diameter reduction direction, so that the independent small protrusion tank 36 is digged into the inner circumferential surface of the distal end diameter expansion pipe part 5, Fig. 4 As shown in Fig., the inner circumferential surface of the distal end diameter-expanded pipe portion 5 and the outer circumferential surface of the connecting tube portion 31 of the in-core 30 are in a state in which the metals are dug into each other (press contact state), and are sealed and sealed with the fluid ( to prevent external leakage of gas or liquid).

In other words, the diameter-reducing biasing force (elastic-repulsive biasing force) of the metal ring 25 in the radial inward direction is used to connect the distal end diameter-expanding pipe portion 5 of the pipe P and the in-core 30 . The sealing state with (31) can be maintained.

In addition, the axial force involved in screwing the cap nut 15 to the flare joint body 20 is transmitted to the in-core 30 through the ring 25, and the flare joint body 20 is It is possible to maintain the pressure-contact sealing state between the front end diameter-reduced tapered portion 20B of the in-core 30 and the inclined surface 32 of the in-core 30 (see FIGS. 3 to 4 and 5 ).

Moreover, as shown in FIGS. 1-5, when performing a connection operation|work, it is preferable to perform the other connection after completing the connection of either one of the left and right.

1 to 5, in the pipe joint structure according to the present invention, a sealing material made of rubber or synthetic resin such as an O-ring for sealing is completely omitted. That is, the component parts are made of metal. For example, the pipe P is Cu or Al, the flare joint body 20 is brass, the cap nut 15 is brass, the in-core 30 is brass or stainless steel, and the ring 25 is hard Al. or stainless steel or the like.

Next, in order for the ring 25 to apply an elastically repulsive biasing force in the direction of large diameter reduction to the pipe portion 5 of the distal end diameter expansion of the pipe P, the thickness dimension T ₂₅ of the ring 25 is set to the pipe P ) compared to the thickness dimension (T _p ), it is preferable to make it large enough.

For example, it is preferable to set so that the following Equation 1 holds.

1.0·Tp≤T ₂₅ ≤2.5·T _p (Equation 1)

More preferably, it is set as in Equation 2 below.

1.2·T _p ≤T ₂₅ ≤2.2·T _p (Equation 2)

In addition, when T ₂₅ is less than the lower limit, the tightening force in the radial inward direction becomes too small, and the sealing property becomes insufficient. Conversely, when the upper limit is exceeded, as the cap nut 15 is turned in, the ring 25 is fitted in the state of FIGS. 3 to 4 or the state of FIGS. 8 to 9 to be described later. get in trouble

Next, in Figs. 6 to 9, another embodiment of the present invention will be described below.

Reference numeral 40 denotes a joint body, in which a male screw portion 37, a stepped portion 38, and a pipe connecting tube portion 41 are integrally formed on both (left and right) sides in the axial direction, respectively. In the center in the axial direction, a bulge 39 for hanging (grasping) a work tool such as a spanner or a wrench is also integrally formed.

Although the cap nut 15 has substantially the same structure as that described in FIGS. 1 to 5, the dimension in the axial direction is short. The female screw portion 15A of the cap nut 15 is screwed to the male screw portion 37 of the joint body 40 .

In the two to-be-connected pipes P and P connected to each other, a tip diameter expansion pipe part 5 is formed over a predetermined axial dimension L ₅ from the tip end surface 3, and further, a tip diameter expansion pipe part ( At the boundary between 5) and the basic diameter tube portion 6, a tapered stepped portion 10 is formed.

In the other embodiment shown in Figs. 6 to 9, the closed annular rings 25 and 25 (described in Figs. 1 to 5) are omitted, and further, the tip diameter reduction taper portion 20B is also omitted. it can be seen that there is

However, in another embodiment, the pipe connecting tube portion 41 integrally protruding from the joint body 40 is formed, and on the outer peripheral surface of the connecting tube portion 41, a plurality of triangular or conical independent small protrusions 36 in cross section. is formed.

The step dimension ΔD of the stepped portion 38 is sufficiently large, and the thickness dimension T ₄₁ of the pipe connection cylindrical portion 41 is formed small (refer to FIG. 7 ).

Then, in a state where the pipe connecting tube portion 41 of the joint body 40 is inserted into the diameter-expanded pipe portion 5 of the pipe P, the cap nut 15 (as shown in Fig. 8) is inserted into the joint body. When turning in (40), while moving in the direction of the arrow (K), through the tapered stepped portion 10, as shown in FIG. 9, a closed round ring-shaped ring ( 25) was installed inside the cap nut 15 .

In the connected state shown in FIG. 9 , the diameter-reducing biasing force in the radial inward direction of the ring 25 causes the distal end diameter expansion pipe 5 of the pipe P and the pipe connection cylinder part of the joint body 40 . (41) and keep the sealed state.

That is, a large force (tightening force) is applied in the diameter reduction direction by the ring 25, and the independent small protrusion tank 36 is in a state where the inner circumferential surface of the diameter-expanding pipe part 5 at the distal end is in a state shown in FIG. As shown, the inner circumferential surface of the distal end diameter-expanding pipe portion 5 and the outer circumferential surface of the connecting tube portion 41 of the joint body 40 are sealed in a state of mutual penetration of metals to prevent external leakage of the fluid.

In other words, the diameter-reducing biasing force (elastic-repulsive biasing force) of the metal ring 25 in the radial inward direction is used to connect the diameter-expanded pipe portion 5 at the tip of the pipe P and the joint body 40 . A fluid sealing state with (41) can be maintained.

6 to 9, in the pipe joint structure according to the present invention, a sealing material made of rubber or synthetic resin, such as an O-ring for sealing, is completely omitted. That is, the component parts are made of metal. For example, the pipe P is made of Cu, Al or stainless steel, the joint body 40 is made of brass, the cap nut 15 is made of brass, and the ring 25 is made of hard Al or stainless steel.

Next, in order to apply an elastic repulsive biasing force in the direction of large diameter reduction of the ring 25 to the pipe portion 5 of the pipe P with an enlarged tip diameter, the thickness dimension T ₂₅ of the ring 25 is set to the pipe ( Compared with the thickness dimension (T _p ) of P), it is preferable to make it large enough.

That is, in the other embodiment shown in FIG. 10 and FIG. 11, it has shown that the thickness dimension T ₂₅ of the ring 25 can be set large (compared to embodiment of FIGS. 6-9).

Comparing FIGS. 10 and 11 with FIGS. 6 to 9 described above, the outer diameters of the male threaded portion 37 and the bulging portion 39 of the joint body 40 are set sufficiently large to be clear, and the connecting tube portion By leaving the shape and dimensions of (41) as it is, the outer diameter of the stepped portion 38 can be set sufficiently large. That is, it is possible to sufficiently increase the step dimension ?D.

In the cap nut 15, its radial dimension is increased. That is, the female screw portion 15A and the medium diameter portion 15C of the cap nut 15 can be set to be large, and the outer diameter dimension can be greatly increased. The reason for this is that the joint body 40 shown in Figs. 6 to 11 is a novel shape independent of the JIS standard, and it is possible to increase the dimension in the radial direction.

In the embodiments shown in Figs. 6 to 9 and Figs. 10 and 11 , since the step dimension ΔD is sufficiently large, the thickness dimension T ₂₅ of the ring 25 can also be set to be large (in proportion). As described above, the ring 25 having a large thickness dimension (T ₂₅ ) can apply an elastic repulsive biasing force in the large diameter reduction direction to the diameter expansion pipe part 5 at the tip of the pipe (P).

For example, it is preferable to set so that the following Equation 3 holds.

1.2·T _p ≤T ₂₅ ≤3.0·T _p (Equation 3)

More preferably, it is set as in Equation 4 below.

1.4·T _p ≤T ₂₅ ≤2.8·T _p (Equation 4)

Further, when T ₂₅ is less than the lower limit, the tightening force in the radial inward direction becomes slightly excessive, and the sealing property becomes slightly insufficient. Conversely, when the upper limit is exceeded, by turning the cap nut 15 in, the ring 25 is fitted in the state of Figs. 8 to 9 or the state of Figs. 11 to 10 described later. get in trouble

10 and 11, by increasing the thickness dimension T ₂₅ as shown in Equations 3 and 4 above, the pipe pulling-out force is large and the sealing performance is maintained very high.

In the present invention, one basic component requirement is to provide the distal end diameter-expanded pipe portion 5 to the pipe P for connection. Then, the distal end diameter expansion pipe portion 5 will be described below.

As shown in Fig. 12, the tip of the pipe to be processed P ₀ is inserted into the hole 26A of the split die 26, and the diameter expansion piece of the cross-section sector is divided into four (or more). (27) is inserted at a predetermined depth with respect to the pipe (PO). When the tapered male mold 28 is pushed in the direction of the arrow E into the tapered hole 29 formed by the divided diameter expansion piece 27, the diameter as shown in Figs. 12(A) to (B) The expanded piece 27 moves in the radial outward direction R, so that the distal end diameter expansion pipe 5 is formed (processed).

Further, in order to form the tapered stepped portion 10, a tapered portion 27A is made in the diameter extension piece 27, and a tapered portion 26B is made in the hole portion 26A of the mold 26. have.

After that, when the mold 26 is divided in the diameter expansion direction and the processed pipe P ₀ is pulled out, the tip diameter expansion pipe portion 5 as shown in FIGS. 1 to 6 and 8 to 11 , etc. A pipe P for forming and connecting is produced.

From a long time ago, the manual tool for diameter expansion shown in Fig. 12 has been widely known. The reason is that the brazed pipe connection 63 as shown in FIG. 13 has been used for a refrigerant pipe or domestic hot water supply (water) pipe for a long time. That is, for the brazed pipe connection 63 that has been practiced for a long time, one pipe 61 is pre-processed with the distal end diameter expansion pipe part 5 shown in Figs. 1 to 6 and Figs. because I needed to do it. (In addition, the other pipe 62 is inserted into the diameter expansion pipe part 5 as it is without processing, and the mutual fitting surface part X ₅ is brazed.)

In this way, the present inventors focused on the diameter expansion work tool widely used for pipe connection work by brazing, and the tip diameter expansion pipe part that can be easily processed by it, and the original shape as shown in FIGS. 1 to 11 . By combining the structure with the structure, it is possible to work safely without using heat such as brazing, and moreover, it does not have an ultra-precise digging claw 80, etc., compared to FIG. An excellent pipe joint structure is proposed here.

The present invention, as described in detail above, includes a flare joint body 20 having an external threaded portion 20A and a tip diameter-reduced tapered portion 20B on each of both sides in the axial direction, and the male threaded portion 20A is screwed into A cap nut 15 having a female threaded portion 15A coupled thereto is provided, and two to-be-connected pipes P connected to each other extend from the distal end face 3 to a predetermined axial center dimension L ₅ . 5) is formed, and at the boundary between the tip diameter expansion pipe part 5 and the basic diameter pipe part 6, a tapered stepped part 10 is formed, and the tip diameter expansion pipe part of the pipe (P) ( 5) and an in-core 30 having a sloping surface 32 abutting against the diameter-reduced tapered portion 20B at the tip, and a flare joint body 20 of the cap nut 15 ), through the tapered stepped portion 10 of the pipe (P), the closed round ring-shaped ring 25 that is fitted from the outside into the diameter-extended pipe portion 5 of the tip is inserted into the cap nut (15). Installed in the inside of the ring 25, the diameter reduction biasing force in the radial inward direction, the pipe (P) end diameter expansion pipe portion 5 and the connecting tube portion 31 of the in-core (30) The axial force accompanying the screwing of the cap nut 15 to the flare joint body 20 is transmitted to the in-core 30 through the ring 25, Since it is configured to maintain the pressure-contact sealing state between the tip diameter reduction tapered portion 20B of the flare joint body 20 and the inclined surface 32 of the in-core 30, there is concern about the durability of the sealing material against the fluid to be sealed. It exhibits excellent sealing performance over a long period of time. In addition, the problem of quality fluctuations due to flaring at the job site is solved, and parts having extremely fine claws 80 (see Figs. 14 and 15) can be omitted, and strong pull-out resistance is exhibited. It has become possible to stably maintain high sealing properties over a long period of time under a harsh operating environment with an extremely large temperature difference and high pressure acting. As a union-type pipe joint (connecting pipes (P)... one after another) most often used in piping for flowing fluids, it has greatly contributed to the industry, and has an extremely temperature difference of -70°C to +150°C. Even if it is large and high pressure acts, strong pulling-out resistance and high sealing property can be stably maintained.

In addition, since a plurality of triangular to conical independent small protruding tanks 36 are formed on the outer peripheral surface of the connecting tube portion 31 of the in-core 30, It can penetrate reliably and deeply into the inner circumferential surface, and exhibit large pull-out resistance and high sealing performance with respect to various fluids to be sealed.

Further, in the present invention, a joint body 40 in which an external threaded portion 37, a stepped portion 38, and a pipe connection cylindrical portion 41 are sequentially formed on each of both sides in the axial direction, and the male threaded portion 37 Two cap nuts 15 having female threaded portions 15A to be screwed are provided, and two to-be-connected pipes P connected to each other have a distal end diameter from the distal end face 3 to a predetermined axial dimension L ₅ . While the expanded pipe part 5 is formed, a tapered stepped part 10 is formed at the boundary between the tip diameter expanded pipe part 5 and the basic diameter pipe part 6, and the pipe of the joint body 40 Taper of the pipe (P) by inserting the cap nut (15) into the joint body (40) of the cap nut (15) in a state in which the connecting tube (41) is inserted into the distal end diameter expansion pipe (5) of the pipe (P) A closed round ring-shaped ring 25 that is fitted from the outside to the front end diameter expansion pipe part 5 through the shape step attachment part 10 is installed inside the cap nut 15, and the radial of the ring 25 is Since the sealing state between the diameter-expanding pipe part 5 at the tip end of the pipe P and the pipe connection cylinder part 41 of the joint body 40 is maintained by the inward diameter-reducing biasing force, the fluid to be sealed It exhibits excellent sealing properties over a long period of time without worrying about the durability of the sealing material. In particular, the number of parts is small, and compactness and simplification of the structure can be achieved. In addition, since the pressure-contact sealing portion of the tapered surfaces was completely omitted (the location to be sealed against external leakage can be halved), the sealing property can be further improved.

In addition, the problem of quality fluctuations due to flaring processing on the job site is also solved, and parts having a very ultra-precise claw 80 (see FIGS. 14 and 15) can be omitted, and a strong pull-out resistance is exhibited. For example, under a harsh operating environment such as an extremely large temperature difference and high pressure acting, it only has strong pressure welding between metals, and high sealing properties are stably exhibited over a long period of time.

In addition, since a plurality of independent small protruding troughs 36 of triangular to conical cross-section are formed on the outer peripheral surface of the pipe connecting tube portion 41 protruding from the joint body 40, the diameter of the distal end of the metal pipe P is expanded. It is reliably and sufficiently deeply penetrated into the inner peripheral surface of (5), and a large pull-out resistance and high sealing performance can be exhibited with respect to the fluid to be sealed. Moreover, between the joint body 40 and the pipe P, the only place where there is a risk of fluid leakage is the connecting tube portion 41 in which the independent small protrusion tank 36 is formed, so that a very high sealing performance as a whole of the pipe joint is achieved. can be said to keep

In addition, since the sealing material for sealing is completely omitted and all components are made of metal, it exhibits stable sealing performance under extremely low temperature (-70°C) to ultra-high temperature (+150°C) and extremely harsh environments, and has particularly excellent durability. It is a union type tube joint structure.

In addition, if the thickness dimension of the closed annular ring 25 is T ₂₅ and the thickness dimension of the pipe P is T _p , 1.0·T _p ≤ T ₂₅ ≤ 2.5·T _p is established. , because the size is set, a strong elastic repulsion diameter reduction biasing force of the metal ring 25 is generated toward the radial inward direction, and the metal pipe P is sufficiently strongly pressed against the connecting tube portion 31 (41). Moreover, even with large temperature fluctuations from low to high temperature, high sealing performance is stably exhibited, and durability is excellent.

3 front end
5 End diameter expansion pipe part
6 Basic diameter pipe
10 Tapered Stepped Part
15 cap nut
15A female thread
20 flare joint body
20A male thread
20B tip diameter reduction tapered part
25 Closed round ring shape ring
30 in core
31 connection
32 graded surface
36 Independent small protrusion tank
37 male thread
38 tiered part
40 joint body
41 connection tube
P pipe
L ₅ Predetermined axial center dimension
T ₂₅ ring thickness dimension
T _p pipe thickness dimension

Claims (6)

A cap nut having a flare joint body 20 having a male threaded portion 20A and a tip diameter-reduced tapered portion 20B on each of both sides in the axial direction, and a female threaded portion 15A screwed to the male threaded portion 20A ( 15) equipped,
In the two to-be-connected pipes P connected to each other, a tip diameter expansion pipe part 5 is formed from the tip end face 3 to a predetermined axial dimension L ₅ , and the tip diameter expansion pipe part 5 and the base At the boundary with the diameter pipe part 6, a tapered stepped part 10 is formed,
An in-core (30) having a connecting tube part (31) interpolated into the tip diameter expansion pipe part (5) of the pipe (P), and a sloped surface (32) abutting the tip diameter reduction taper part (20B),
By screwing the cap nut 15 into the flare joint body 20, a closed round ring that is fitted from the outside into the tip diameter expansion pipe part 5 via the tapered stepped part 10 of the pipe P. A shape ring (25) is installed inside the cap nut (15),
By the radially inwardly reducing biasing force of the ring 25, the sealing state between the diameter-extended pipe part 5 of the pipe P and the connecting tube part 31 of the in-core 30 is maintained, ,
In addition, the axial force accompanying the screw coupling of the cap nut 15 to the flare joint body 20 is transmitted to the in-core 30 through the ring 25, so that the A pipe joint structure characterized in that it is configured to maintain a pressure-contact sealing state between the tip-end diameter-reduced tapered portion (20B) and the inclined surface (32) of the in-core (30). According to claim 1,
A pipe joint structure in which a plurality of independent small protruding troughs 36 of triangular to conical cross-section are formed on the outer peripheral surface of the connecting tubular portion 31 of the in-core 30 . A joint body 40 in which a male threaded part 37, a stepped part 38, and a pipe connection cylindrical part 41 are sequentially formed on each of both sides in the axial direction, and a female threaded part screwed to the male threaded part 37 ( 15A) with two cap nuts (15),
In the two to-be-connected pipes P connected to each other, a tip diameter expansion pipe part 5 is formed from the tip end face 3 to a predetermined axial dimension L ₅ , and the tip diameter expansion pipe part 5 and the base At the boundary with the diameter pipe part 6, a tapered stepped part 10 is formed,
In the state in which the pipe connecting tube portion 41 of the joint body 40 is inserted into the distal end diameter expansion tube portion 5 of the pipe P, the cap nut 15 is inserted into the joint body 40 By this, a closed round ring-shaped ring 25 that is fitted from the outside to the tip diameter expansion pipe part 5 through the tapered step attachment part 10 of the pipe P is installed inside the cap nut 15, ,
With the diameter-reducing biasing force of the ring 25 in the radial inward direction, the sealing state between the diameter-expanding pipe part 5 at the tip of the pipe P and the pipe connection cylinder part 41 of the joint body 40 is maintained. A pipe joint structure, characterized in that it is configured to do so. 4. The method of claim 3,
A pipe joint structure in which a plurality of independent small protruding troughs 36 of triangular to conical cross-section are formed on the outer peripheral surface of the pipe connecting tube portion 41 protruding from the joint body 40. 5. The method of claim 1, 2, 3 or 4,
A pipe joint structure in which all components are made of metal by completely omitting the sealing material for sealing. 6. The method of claim 1, 2, 3, 4 or 5,
When the thickness dimension of the closed ring-shaped ring 25 is (T ₂₅ ) and the thickness dimension of the pipe (P) is (T _p ), the pipe joint structure is dimensioned so that Equation 1 is established.
1.0·T _p ≤T ₂₅ ≤2.5·T _p (Equation 1)

Images