JP7185885B2 - pipe joint - Google Patents

Description

The present invention relates to pipe joints.

A flare joint is widely known as one type of pipe joint. In general, as shown in FIG. 17, this flared joint is formed by forming a flared portion f at the end of a pipe p by plastic working with a special jig, and this flared portion f is formed on the flared joint main body h. The cap nut n is applied to the tapered portion a and tightened, and the tapered surface t of the cap nut n and the tapered portion a of the flare joint main body h are pressed against each other, and the metal surfaces are pressed against each other to ensure the sealing performance. (See Patent Document 1, for example).
However, with the pipe joint shown in FIG. 17, it is necessary to use a special tool to form the flared portion f at the end of the pipe to be connected p at the work site, resulting in poor work efficiency and poor quality. Variation also occurs. Furthermore, the small diameter edge f ₁ of the flared portion f of the pipe p is likely to crack. Moreover, when the cap nut n is tightened, the thickness of the pipe p is reduced, and as a result, there is a problem that the sealing performance is deteriorated and the cap nut n is easily loosened.
Therefore, the present applicants have proposed a pipe joint capable of connecting a pipe p in which the flared portion f shown in FIG. 17 is completely omitted.

That is, it is a pipe joint having a structure as shown in FIG. 18 (see Patent Document 2). The pipe joint described in FIG. 18 (Patent Document 2) has a flare joint main body 51 having a male screw portion 52 and a tapered portion 53, and a cap nut 54 is screwed thereon. The stop ring 56 is internally held.
This stop ring 56 has a seal recessed groove 57, and an O-ring 58 is installed therein, and the sealing action between the stop ring 56 and the pipe P into which it is inserted is performed by this O-ring 58. As shown in FIG. In particular, the stop ring 56 has a pressure sloped surface 59 that presses against the tapered portion 53 of the joint body 51 . Further, a thin cylindrical portion 60 extends with the same diameter on the tip end side, and at the tip of the thin cylindrical portion 60, a pawl portion 61 for biting into the outer peripheral surface of the pipe having a triangular cross section is attached.
The claw portion 61 is configured to bite into the outer peripheral surface of the pipe P as the cap nut 54 is screwed (see Patent Document 2).

JP-A-2005-42858 Japanese Patent No. 5091191

However, the following two points remain unresolved or are technically inadequate in order to actually provide the pipe joint shown in FIG. 18 (Patent Document 2) to the market for use in refrigerant pipes. But it became clear.
(i) As the cap nut 54 is screwed, the stop ring 56 rotates together, causing a relative slip between the tapered portion 53 and the pressure gradient surface 59, thereby destroying the metal pressure contact seal. be. In order to prevent this, "preliminary processing" is required in which the claw portion 61 is made to bite into the outer peripheral surface of the pipe P in advance using a special jig.
Such "preliminary work" significantly reduces work efficiency at the piping connection site.
(ii) The thickness of the actual pipe P is approximately the same as the thickness of the thin cylindrical portion 60, and may be about 1/3 of the thickness Tp shown in FIG. Therefore, even the claw portion 61 having a triangular cross section does not bite into the surface of the Cu pipe P, but only locally plastically deforms the pipe P in the inner diameter direction, and the pipe pull-out resistance is small.

Accordingly, the present invention provides a flare joint main body having a male threaded portion and a tapered surface with a reduced diameter at the tip end, and a female threaded portion screwed to the male threaded portion at the base end of the hole. A cap nut having a storage space formed in the middle thereof, which has a portion of the same diameter, a stepped portion, and a tapered portion with reduced diameter at the tip; A pipe joint comprising a stop ring having a side pressure contact gradient surface and a plastically deformable thin-walled substantially cylindrical portion on the tip end side and a tooth portion for preventing the pipe from being pulled out at the top of the stop ring, wherein: The portion is composed of a rear tooth and a front tooth arranged with a minute interval, the cross-sectional shape of the rear tooth is substantially trapezoidal, and the first tip side formed by the upper side of the substantially trapezoidal shape is , the front tooth has a low rear half side portion and a tall front half side portion through the rounded intermediate step portion, and the cross-sectional shape of the front tooth is substantially trapezoidal, and furthermore, from the upper side of the substantially trapezoidal shape The second tip side, which is formed, is in the shape of a polygonal line having a short rear half side portion and a tall front half side portion via a rearwardly downward inclined surface.

Further, the first tip side of the rear tooth of the stop ring and the second tip side of the front tooth of the stop ring forcefully move against the outer peripheral surface of the straight tip portion of the pipe to be connected as the cap nut is screwed. In the pressure contact state, a pipe pull-out resistance force is generated. Further, in the strong pressure contact state, the first tip side of the rear teeth and the second tip side of the front teeth contact the outer peripheral surface of the pipe. It is constructed so as to perform a double seal function by press-contacting in a bite-like manner.
In addition, the seal material is omitted from the inner peripheral surface and the outer peripheral surface of the stop ring so as to exhibit the above-described double sealing function in a state of strong pressure contact.

In addition, even if the pipe rotates about its axis under the strong pressure contact condition, the front side of the first tip side of the rear teeth forms a closed annular small groove on the outer peripheral surface of the pipe. to prevent helical rotation of the pipe, and furthermore, the rounded intermediate stepped portion of the first tip side comes into pressure contact with the rear side surface of the small recessed peripheral groove to exert a sealing function. .

Further, the rear teeth and the front teeth share the outer peripheral surface of the pipe so that the resistance to the pipe pullout of the front teeth is greater than the resistance to the pipe pullout of the rear teeth in the strong pressure contact state, and the front teeth The second tip side of is strongly pressed against the outer peripheral surface with the shape of the broken line, and the front teeth share the function of preventing the pipe from coming out due to the external force in the bending direction.
Further, the rear teeth and the front teeth are the same with respect to the outer peripheral surface of the pipe so that the first tip side and the second tip side are equidistant from the axial center of the pipe under the strong pressure contact state. It was configured to let it bite into the depth.
Further, in the hole portion of the cap nut, the tapered portion with a reduced diameter at the tip is composed of a steep taper portion on the proximal end side, an intermediate gentle taper portion, and an intermediate steep taper portion and a gentle taper portion on the tip end side. there is

Further, in the hole portion of the cap nut, the tapered portion with reduced diameter at the tip is composed of a steep taper portion on the proximal end side, an intermediate gentle taper portion, and an intermediate steep taper portion and a gentle taper portion on the tip end side. Further, the tip head portion of the thin-walled substantially cylindrical portion is formed on the outer periphery of the tip head portion at an axial position corresponding to the axial position of the rear teeth, and the first convex portion composed of the distal end outer peripheral corner portion. and a low triangular hill-shaped second convex portion formed on the tip, and as the cap nut is screwed, the tip head portion slides into the tip diameter-reduced tapered portion, the second convex portion is formed. is pressed radially inward by the proximal-side steeply tapered portion to perform a first pressing step of pressing the rear tooth against the outer peripheral surface of the pipe, and then the first convex portion is pushed into the intermediate steeply sloped portion. The tapered portion presses radially inward to perform a second pressing step of pressing the front teeth against the outer peripheral surface of the pipe.

Further, the stop ring has a basic inner diameter portion into which the pipe is inserted and a basic outer diameter portion that is internally accommodated in the storage space for the cap nut. The stepped portion formed by the tip end surface of the cylindrical portion and the stepped portion of the hole portion of the cap nut come into contact with each other when the cap nut is completely tightened, thereby increasing the spiral resistance of the cap nut. It is a configuration that enables detection by a person.
Further, a supporting inner core is attached to support the tip portion of the pipe from the inner peripheral side while the rear teeth and front teeth of the stop ring are in the strong pressure contact state with the outer peripheral surface of the pipe.

According to the present invention, the two rear teeth and the front teeth are strongly pressed against the outer peripheral surface of the pipe, so that the pipe pull-out resistance is large and excellent sealing performance (sealing property) against refrigerant and the like is exhibited. Furthermore, the "preliminary processing" described in the conventional problem (i) can be omitted, and the pipe connection work can be performed quickly and efficiently. In addition, while the rear teeth and front teeth each exhibit their own functions (actions) and complement each other, they have excellent overall sealing performance (sealing performance) and pull-out resistance when bending force acts on the pipe. It is possible to reliably prevent the accident that the pipe is pulled out.

It is a sectional view showing an embodiment of the present invention and showing a state in the middle of pipe connection. It is a sectional view showing a pipe connection completion state. It is sectional drawing which shows an example of a cap nut, Comprising: (A) is general sectional drawing, (B) is principal part enlarged sectional drawing. It is sectional drawing of a stop ring, Comprising: (A) is sectional drawing of one Example, (B) is sectional drawing which showed only the upper half part of another Example. FIG. 4 is an enlarged cross-sectional view of a main part of the stop ring; It is explanatory drawing which illustrated the cross-sectional shape of a rear tooth. It is explanatory drawing which illustrated the cross-sectional shape of a front tooth. FIG. 4 is an enlarged cross-sectional explanatory view of a main part showing an initial set state of the tip head. FIG. 4 is an enlarged cross-sectional explanatory view of a main part for sequentially explaining the operation of the tip head. FIG. 4 is an enlarged cross-sectional explanatory view of a main part for sequentially explaining the operation of the tip head. FIG. 4 is an enlarged cross-sectional explanatory view of a main part for sequentially explaining the operation of the tip head. FIG. 4 is an enlarged cross-sectional explanatory view of a main part for sequentially explaining the operation of the tip head. FIG. 4 is an enlarged cross-sectional explanatory view of a main part for sequentially explaining the operation of the tip head. FIG. 4 is an enlarged cross-sectional explanatory view of a main part for sequentially explaining the operation of the tip head. FIG. 4 is an enlarged cross-sectional explanatory view of a main part showing a state of strong pressure contact; FIG. 10A is a diagram showing another embodiment, in which (A) is an enlarged cross-sectional view of a main part in an initial setting state (of the tip head), and (B) is an enlarged cross-sectional view of a main part showing a strong pressure contact state. FIG. 11 is a cross-sectional view showing a conventional example; FIG. 10 is a cross-sectional view showing another conventional example;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on the illustrated embodiments.
In the embodiment shown in FIGS. 1 to 5, a pipe joint J according to the present invention comprises a flare joint body 1, a cap nut 2 and a stop ring 3. It has a straight tip 10 (omitting the conventional flaring altogether).

The flare joint main body 1 has been used for a long time, and is similar to the flare joint main body h shown in FIG. In other words, the leading end diameter reducing slope surface 5 is formed at the leading end of the connecting tube portion 7 through which the passage hole 6 is provided.
The overall shape may be straight, T-shaped, Y-shaped, cross-shaped, or the like. It is free to have the same connection tube portion 7 as in the above, or to have a tapered male thread, a parallel female thread, a welding tube portion, or the like.
In short, as shown in FIGS. 1 and 2, at least one connecting tube portion 7 is provided, and in the examples of FIGS. The connection tube portion 7 has a male screw portion 9 of a parallel screw through. A suitable material for the flare joint main body 1 is brass.

The cap nut 2 has a hole 11 extending axially (as shown in FIGS. 1 to 3), and the proximal end of the hole 11 is a female screw into which the male threaded portion 9 is screwed. A seal groove ₁₃ having a small width dimension W13, a first same diameter portion (first straight portion) 14A, a second same diameter portion (first straight portion) 14A, and a second same A diameter portion (second straight portion) 14B, a stepped portion 15, a short straight portion 16 with a small width dimension W ₁₆ , a tapered portion 17 with a reduced diameter at the tip, and an inner diameter dimension slightly larger than the outer diameter of the connected pipe P ) a straight portion 18 is formed. In some cases, the short straight portion 16 can be omitted (in the case of a small diameter).

A groove portion 19 is formed in the straight portion 18, and a seal 48 such as an O-ring is attached. Also, another seal 46 such as an O-ring is mounted in the seal groove 13 . The first same-diameter portion 14A is set to have an inner diameter slightly larger than that of the second same-diameter portion 14B.
The same diameter portions 14A and 14B of the hole portion 11, the stepped portion 15, the short straight portion 16 and the tapered portion 17 with reduced diameter at the tip form a storage space portion E for storing the stop ring 3. As shown in FIG. (The short straight portion 16 may be omitted in some cases.) The material of the cap nut 2 is brass or aluminum.

Then, as shown in FIG. 3(B), in the hole 11 of the cap nut 2, the tapered portion 17 with reduced diameter at the tip is composed of a steep tapered portion 17A on the proximal end side, an intermediate gentle slope taper portion 17B, and an intermediate steep tapered portion 17B. It is composed of a sloped tapered portion 17C, a tip-side gently sloped tapered portion 17D, and the like.
The proximal side steep taper portion 17A and the intermediate steep taper portion 17C are set to have the same slope (inclination) angle. Moreover, the width dimensions of both steep taper portions 17A and 17C are set to be the same.
Further, as is clear from FIG. 3B, the slope (tilt) angle of the intermediate gently sloped taper portion 17B is set to a value equivalent to the slope (tilt) angle of the tip-side gently sloped taper portion 17D, or , the gradient (inclination) angle of the latter tapered portion 17D is set slightly larger. Moreover, the width dimension of the latter tapered portion 17D is smaller.
FIG. 3A illustrates a case in which the first and second same diameter portions 14A and 14B having slightly different inner diameters are used as the same diameter portion (straight portion) 14. Therefore, in some cases, the first same diameter portion 14A and the second same diameter portion 14B may have exactly the same inner diameter.

Next, the stop ring 3 will be explained. As shown in FIG. 4 and FIGS. 1 to 3, the stop ring 3 is installed inside the storage space E of the cap nut 2. As shown in FIG. The stop ring 3 has a substantially short cylindrical shape, and has a basic outer diameter portion 24 that is slidably fitted in the straight portion 14 of the hole portion 11 of the cap nut 2 from the base end to the intermediate region of the outer peripheral surface. , and a tapered thin-walled substantially cylindrical portion 35 having a small diameter and gradually increasing in diameter toward the distal end, connected to the distal end side via the stepped portion 25 .
The inner peripheral surface 27 also has a basic inner diameter 28 in the middle in the axial direction, into which the pipe P is inserted (as shown in FIG. 1).

Further, the base end portion of the basic inner diameter portion 28 is continuously provided with an inner protruding portion 29 having a small diameter inner peripheral surface portion 29A. One end surface of the inner protruding portion 29 (on a surface orthogonal to the axis) serves as a stepped surface 30 .
Reference numeral 32 denotes a radiused (convex) pressure contact gradient surface, which is formed at the proximal end of the stop ring 3 and, as shown in FIGS. to provide a sealing effect.

By the way, in the embodiment of FIG. 4(A), an annular small ridge 40 is provided at the intersection of the inner peripheral edge of the radius pressure contact gradient surface 32 and the small diameter inner peripheral surface portion 29A. .
Specifically, as shown in FIGS. 1, 2, and 4A, an annular ring formed by the tip of the tip diameter-reducing slope surface 5 of the joint body 1 and the joint body hole portion 6 The stop ring 3 has an annular small ridge 40 hooked on the tip edge portion 20 from the inner diameter side.

As is clear from FIG. 4(A), the small ridge 40 has a cross-sectional shape of an inverted triangle. A small oblique side that is reversed outward through the center and the small-diameter inner peripheral surface portion 29A form a sideways triangular shape.
As shown in FIGS. 1 and 2, the annular small ridge 40 is hooked from the annular distal end edge portion 20 of the joint body 1 from the inner diameter side in this way, so that the stop ring 3 can be can be prevented from deforming excessively radially outward. As shown in FIG. 4(B), it may be preferable to omit the annular small ridge 40 shown in FIG. 4(A).

Then, as shown in FIG. 4, at least the inner portion 31 of the pipe insertion hole portion 3A of the stop ring 3 is formed in a tapered shape with a reduced inner diameter. That is, in FIG. 4, at least the inner portion 31 is tapered with a very small inclination angle .theta.--for example, 0.5.degree. In the completed state, the distal end portion 10 of the pipe P is configured to press against the deep portion 31 of the inner peripheral surface 27 of the pipe insertion hole portion 3A.

The stop ring 3 integrally has a plastically deformable thin substantially cylindrical portion 35 on the distal end side. In addition, a tip head portion 37 of the thin-walled substantially cylindrical portion 35 is provided with a tooth portion 36 for preventing the pipe from being pulled out.
As shown in an enlarged cross-section in FIG. 5, the tooth portion 36 is composed of a rear tooth _36B and a front tooth 36F arranged with a minute interval W36.
The thin-walled substantially cylindrical portion 35 has a conical cylindrical shape with a diameter that is slightly enlarged toward the distal end (see FIGS. 4 and 5).
4A and 5, the thickness dimension of the basic short cylindrical portion 50 consisting of the basic inner diameter portion 28 and the basic outer diameter portion 24 is defined as T50, and the average thickness of the thin approximately cylindrical portion 35 is _T50 . Assuming that the thickness dimension is _T35 , the thin substantially cylindrical portion 35 is formed relatively thick so that 0.40· _T50 ≤ _T35 ≤ 0.75· _T50 (Equation 1) is established. (In FIG. 5, the average wall thickness dimension _T35 is obtained by excluding the front teeth 36F and the rear teeth 36B, which are divided by the dotted lines _LF and _LB. )

In other words, the thin substantially cylindrical portion 35 has an average thickness dimension T ₃₅ which is sufficiently large as 40% to 75% of the thickness dimension T ₅₀ of the basic short cylindrical portion 50 .
It should be noted that it is preferable to set 0.43·T ₅₀ ≦T ₃₅ ≦0.65·T ₅₀ (formula 2).
Further, it is desirable to set 0.45·T ₅₀ ≤ T ₃₅ ≤ 0.55·T ₅₀ (equation 3).
In the above formula, it is difficult to withstand the internal pressure below the lower limit. Conversely, when the upper limit is exceeded, the stepped portion 25 becomes too small, making it difficult for the operator to detect an increase in screw resistance of the cap nut 2 (to be described later). If the lower limit value or the upper limit value is exceeded, the tip head portion 37 will not bite into (restrict) the outer peripheral surface 10A of the pipe P reliably and smoothly as shown in FIGS. 8 to 15 (to be described later).

1, 2 and 4 are referred to as rear teeth 36B and front teeth 36F by viewing the front end (right) direction as "front".
As shown in FIGS. 6(D) and 5, the rear tooth 36B has a substantially trapezoidal cross-sectional shape, and the first tip side 41, which is the upper side of the substantially trapezoidal shape, has a rounded intermediate stepped portion. Through 62 , it has a short rear side 63 and a tall front side 64 . Alternatively, the cross-sectional shape of the rear teeth 36B is trapezoidal or substantially trapezoidal with the linear first tip side 41 as the upper side (see FIGS. 6A, 6B, and 6C). It should be noted that FIG. 6 can be seen as an enlarged view of the rear teeth 36B in the X section of FIG.

FIG. 6(A) shows a case where the cross-sectional shape of the rear teeth 36B is trapezoidal, FIG. 6(B) shows a substantially trapezoid with concavely curved left and right oblique sides, and FIG. A case is illustrated in which the rear oblique side is steep and the front oblique side is concavely curved.

As shown in FIGS. 7 and 5, the cross-sectional shape of the front tooth 36F is trapezoidal or substantially trapezoidal having the linear second tip side 42 as its upper side (see FIGS. 7A to 7C). It is also desirable that the linear second tip side 42 in FIGS. 7A to 7C be slightly upwardly inclined rightward (forward). In other words, it is possible to increase the resistance against the pipe P coming off. Alternatively, as shown in FIG. 7(D), it is desirable to form a substantially trapezoid having a polygonal second tip side 42 as the upper side. That is, the second tip side 42 of the front tooth 36F shown in FIG. 7(D) is formed by a polygonal line having a short rear half side portion 66 and a tall front half side portion 67 via a sloped surface 65 inclined backward and downward. shape. (This front side portion 67 may be referred to as the tip portion 42A in some cases.) It can be said that FIG.

FIG. 7(A) shows a case where the cross-sectional shape of the front teeth 36F is trapezoidal, and FIG. 7(B) shows a trapezoid with a steep front oblique side. FIG. 7C illustrates a case where the front oblique side of the left and right oblique sides of the trapezoid is steep and the rear oblique side is concavely curved.
In any case, both the rear teeth 36B and the front teeth 36F have cross-sectional shapes whose upper sides are linear or polygonal, and can be called a "table mounting type".

(Already described) The thin substantially cylindrical portion 35 having the rear teeth 36B and the front teeth 36F at the tip thereof has a conical cylindrical shape with a diameter expanding toward the tip as a whole. Also, the first tip side 41 of the rear tooth 36B and the second tip side 42 of the front tooth 36F are formed substantially parallel to each other. The front end portion 42A (front side portion 67) of the rear tooth 36B is provided at a position slightly radially outward of the first front end side 41 of the rear tooth 36B. That is, while the first tip side ₄₁ of the rear tooth 36B is in contact with the straight line L30 parallel to the axis _L3 (see FIG. 4) of the stop ring 3, the second tip side 42 of the front tooth 36F , a minute gap is formed (see FIG. 5). In other words, under the free state of the thin-walled substantially cylindrical portion 35, the dimension (radius) of the first tip side 41 from the axis L _P of the pipe P—that is, the axis L 3 of the stop ring _3— Also, the dimension (radius) of the second leading edge 42 is slightly larger.
In other words, the first tip side 41 and the second tip side 42 have a difference in dimension from the axial center L _P of the pipe P and the axial center L ₃ of the stop ring 3 (they are stepped).

As the cap nut 2 is screwed, the thin-walled substantially cylindrical portion 35 in the free state described above is deformed sequentially as shown in FIGS. 8 to 14, the pipe P is shown in its original shape and dimensions without being deformed. The position and posture of 36F are expressed in an easy-to-understand manner. FIG. 15 shows a (finally narrowed) strong pressure contact state, and shows a state in which the pipe P is specifically deformed. As shown in FIG. 15, the dashed line _L36 indicates the (sunken) radial position of the tooth portion 36 in the strong pressure contact state----the imaginary cylindrical surface position---.

With the radial direction position (virtual cylindrical surface position) indicated by the dashed line _L36 as a target reference, in FIGS. The positions, postures, etc. of the objects are sequentially illustrated.
As sequentially shown in FIGS. 8 to 15, the thin-walled substantially cylindrical portion 35 and the tip head portion 37 are deformed radially inward----constricted deformation---. Since the shape of the tapered portion 17 with reduced diameter at the tip has already been described in FIG.

In FIG. 5, a first convex portion 71 consisting of the most distal outer peripheral corner and a low triangular hill-shaped first protrusion 71 formed on the outer periphery of the thin-walled substantially cylindrical portion 35 at the same axial position as the rear tooth 36B in the axial direction. 2 convex portions 72 are provided.
The outer peripheral surface of the thin-walled substantially cylindrical portion 35 is composed of a curved portion 73 on the inner end side of the stepped portion 25, a cylindrical straight portion 74, a low triangular hill portion of the second convex portion 72, and an inclination decreasing in diameter toward the tip. The portion 75 is formed from.

As is clear from FIG. 5, the inner peripheral surface of the thin substantially cylindrical portion 35 extends from the inner diameter portion 28 (see FIG. 4) toward the distal end with a slight inclination angle _θ1 (with respect to the horizontal line). It forms a substantially conical surface that expands in the direction. The rear tooth 36B and the front tooth 36F are projected with a predetermined minute gap _W36 , and the front tooth 36F has a right-angled edge portion 82 at the front end (tip) of the second tip side 42 (Fig. 7(B)(C)(D)).
Furthermore, the rear tooth 36B has an edge portion 85 at the rear end of the first tip side 41 (see FIG. 6).

In the strong pressure contact state shown in FIG. 15, the first tip side 41 of the rear tooth 36B bites into the pipe outer peripheral surface 10A, and the second tip side 42 of the front tooth 36F bites into the pipe outer peripheral surface 10A. It presses and has a double seal function. Moreover, in the strong pressure contact state shown in FIG. 15, the first tip side 41 and the second tip side 42 generate the pipe pull-out resistance forces Z _B and Z _F . In addition, since the first tip side 41 and the second tip side 42 exhibit the above-described double sealing function under the strong pressure contact state, a sealing material such as an O-ring is placed on the stop ring 3 (as shown in FIG. 1). It is completely omitted from the inner peripheral surface and the outer peripheral surface of.

8 to 15 will be described in order with reference to FIG. 3B, FIG. 5, etc. FIG. portion 16, and the inclined portion 75 (shown in FIG. 5) fits into the intermediate gently sloping tapered portion 17B (shown in FIG. Portion 72A fits into proximal steeply tapered portion 17A.

Next, as the cap nut 2 is screwed, the tip head portion 37 slides into the tapered portion 17, and as shown in FIG. 17A (see FIG. 3(B)) presses radially inward to come into pressure contact with the outer peripheral surface 10A of the pipe P. As shown in FIG. This is called the first push-in process. At this time, the dimensions of each part should be set in advance so that the arc-shaped pressure-contact inclined surface 32 of the stop ring 3 (shown in FIG. 1) is lightly pressed against the inclined surface 5 of the flare joint main body 1. is preferred.

Next, as shown in FIGS. 9 to 10, the second convex portion 72 rides on (presses against) the intermediate gently sloping tapered portion 17B (accompanied by the screwing of the cap nut 2), and furthermore, as shown in FIG. to narrow down. At this time, only the second convex portion 72 is in pressure contact with the tapered portion 17B, and in the first half of the narrowing (as shown in FIG. 10), the rear teeth 36B enter the pipe outer peripheral surface 10A first, and in the latter half ( As shown in FIG. 11), the front teeth 36F are also encroaching (cutting in).
As shown in FIGS. 10 and 11, the inclined portion 75 (see FIG. 5) is formed with a minute gap (non-contact) with respect to the intermediate gently sloping tapered portion 17B.

Next, as shown in FIG. 12, the first convex portion 71 and the second convex portion 72 come into contact with the taper portion 17 of the cap nut 2 at two points. The front first projection 71 abuts the intermediate steep taper portion 17C, and the rear second projection 72 abuts the intermediate gentle taper portion 17B. is rotationally deformed as indicated by arrow _M37 .
After the first pressing step shown in FIG. 9, the second pressing step shown in FIG. 12 is performed. In FIG. 12, the front teeth 36F are rotated by about 2° to 2.5° while sinking.

Next, as shown in FIGS. 13 and 14, the inclined portion 75 of the tip head portion 37 assumes a posture corresponding to the tip-side gentle slope taper portion 17D. In the second half of such narrowing down, the front tooth 36F is mainly narrowed down.
After that, as shown in FIG. 15, the stepped portion 25 of the stop ring 3 comes into contact with the stepped portion 15 of the cap nut 2, and the connecting work is completed. That is, when the cap nut 2 is completely tightened, the stepped portion 25 formed by the tip surface of the basic short cylindrical portion 50 of the stop ring 3 and the stepped portion 15 of the hole portion 11 of the cap nut 2 are in contact with each other. , an increase in screw resistance of the cap nut 2 can be detected by the operator.

8 to 15, the work steps have been sequentially explained. , the second convex portion 72 is pressed radially inward by the proximal-side steeply tapered portion 17A to press the rear teeth 36B against the outer peripheral surface 10A of the pipe P. After that, the first pressing step is performed. The size, shape and structure of each part are such that the part 71 is pressed radially inward by the intermediate steep taper part 17C to perform the second pressing process of pressing the front teeth 36F against the outer peripheral surface 10A of the pipe P. can.

Then, as shown in FIG. 15, under the strong pressure contact state, the front side 64 of the first tip side 41 of the rear tooth 36B (see FIG. 6(D)) and the front side of the second tip side 42 of the front tooth 36F 67 (see FIG. 7(D)) are equidistant from the axis _LP of the pipe P.
That is, the dashed line _L36 shown in FIG. 15 indicates an equal radius (equidistant distance) from the axial center _LP of the pipe P, and above the dashed line _L36 , the front side portion 64 and the front side portion 67 (FIG. 6 ( D) and FIG. 7(D)) sinks into (eats into) the pipe outer peripheral surface 10A.
Thus, if the shape of the outer peripheral surface of the tip head portion 37 and the inclination angle and axial direction position (dimensions) of the tip reduced diameter taper portion 17 are appropriately set, the front half side portion 64 (FIG. 6) of the rear tooth 36B can be (D)) and the anterior side 67 of the front tooth 36F (see FIG. 7(D)) sink under strong pressure so that they are at an equal distance _L36 from the pipe axis _LP . ──cut into the same depth────.

Further, actions and functions under strong pressure contact will be described below with reference to FIGS. 6(D), 7(D), and FIGS.
Assuming that the pipe P receives an external force (rotational torque) and rotates around its axis _LP under the above strong pressure contact state, the front side portion 64 of the rear tooth 36B is positioned against the outer peripheral surface 10A of the pipe. A closed annular small concave circumferential groove _U64 is formed as shown in the enlarged view of FIG. 15(B). The closed annular small concave circumferential groove _U64 functions as a guide groove (rail groove).

The small ridge 68 functions as a rail, and the small concave circumferential groove _U64 regulates the rotation of the pipe _P so that it exists on a plane perpendicular to the pipe axis LP. That is, the rotation of the pipe P is restricted so as not to meander or spirally rotate.
In this way, even if the pipe P rotates, the meandering rotation and spiral rotation are prevented (suppressed) by the engagement of the small ridges 68 and the small concave peripheral grooves U ₆₄ , thereby causing seal failure. can be prevented.

Moreover, as shown in FIG. 15(B), the withdrawal of the pipe P due to internal pressure or the like---the movement in the axial outward direction---is caused by the small convex angle of the pipe outer peripheral surface 10A of the rounded intermediate stepped portion 62. It is strongly blocked by pressure contact (see arrow _P62 ) to the part.
In particular, the high surface pressure indicated by the arrow _P62 is generated in the rounded intermediate step portion 62 on the rear side surface of the small ridge 68, thereby exhibiting a sealing function.

Next, as shown in FIGS. 15A and 15C, under the strong pressure contact state, the second tip side 42 of the front tooth 36F is strongly pressed against the outer peripheral surface 10A in the form of a broken line. A pipe withdrawal prevention function that prevents the pipe P from being pulled out (rightward in the figure) when an external force in the bending direction is received in the vicinity of the rightward outside the figure of the pipe P shown in FIG. The front teeth 36F, which are strongly pressed in the polygonal line shape, are mainly responsible for this. The arrow _P65 in FIG. 15(C) is the "surface pressure" indicating that the sloped surface 65 is strongly pressed against the pipe outer peripheral surface 10A.
It should be noted that FIG. 15(C) shows the pipe P in a non-cross section as in FIG. 15(B).

In the cross-sectional shapes shown in FIGS. 7A, 7B, and 7C, it is also desirable that the second tip side 42 be inclined forward (so that it rises in the direction of the edge portion 82). omit). That is, the second tip side 42, which is highly inclined forward, increases the effect of preventing the pipe P from slipping out.
As shown in FIGS. 15(B) and 15(C), the rear tooth 36B and the front tooth 36F are provided with front side portions 64 and 67 having a small width, thereby solving the problem (ii) of FIG. 18 described above. That is, there is an advantage that it is easy to bite into the outer peripheral surface 10A of the pipe P. Moreover, the rounded intermediate stepped portion 62 of the rear tooth 36B and the sloped surface 65 of the front tooth 36F shown in FIGS. 15B and 15C exhibit an excellent sealing function (performance). Moreover, when the pipe P rotates, the rear teeth 36B can effectively prevent the small ridges 68 from being guided by the small concave circumferential grooves U ₆₄ of the pipe P, thereby effectively preventing the seal surface from meandering. Performance has also improved.

Furthermore, the bent-line front teeth 36F act to block (prevent) the movement in the direction of pulling out the pipe and not to transmit the influence to the rear teeth 36B. Moreover, even if the pipe P bends, the front teeth 36F exhibit a strong pull-out prevention force, and the rear teeth 36B effectively prevent spiral rotation and meandering rotation even if the pipe P rotates. When the internal pressure acts on the pipe P, the intermediate stepped portion 62 increases the surface pressure P ₆₂ and exerts both a sealing function and a function of preventing the pipe from being pulled out.
As described above, according to the present invention, the rear teeth 36B and the front teeth 36F cooperate with each other to sufficiently exert the function of preventing the pipe P from being pulled out and the function of sealing.

Next, another embodiment shown in FIG. 16 will be described. In-core 83 for support is attached. That is, this inner core 83 has a cylindrical portion 86 having an outer collar 84 at one end. 1 and 2 show states corresponding to FIGS. 16(A) and 16(B), respectively, and the same reference numerals as in the embodiment described in FIGS. 1 to 15 denote the same configurations. This is effective when the wall thickness dimension of the pipe P is small (thin). The material of the inner core 83 is SUS or Cu.

As described in detail above, the present invention comprises a flare joint main body 1 having a male threaded portion 9 and a tapered tip surface 5, and a female threaded portion 12 screwed onto the male threaded portion 9 at the base of a hole portion 11. a cap nut 2 formed at an end thereof and formed with a storage space E having a same diameter portion 14, a stepped portion 15 and a reduced diameter taper portion 17 in the middle of the hole portion 11; E and has a base-side pressure-contact sloped surface 32 that presses against the tip diameter-reducing sloped surface 5, and a plastically deformable thin-walled substantially cylindrical portion 35 and its tip head portion 37 on the tip side to pull out the pipe. In a pipe joint provided with a stop ring 3 having blocking teeth 36, the teeth 36 are composed of rear teeth 36B and front teeth _36F arranged with a minute interval W36, and are connected. The first tip side 41 of the rear tooth 36B of the stop ring 3 and the second tip side 42 of the front tooth 36F of the stop ring 3 are screwed on the outer peripheral surface 10A of the straight tip portion 10 of the pipe P. As a result, the stop ring 3 is configured to generate a strong pressure contact state and generate a pipe pull-out resistance force Z, and the stop ring 3 is provided between the basic inner diameter portion 28 into which the pipe P is inserted and the storage space portion E for the cap nut 2. The thickness dimension of the basic short cylindrical portion 50 consisting of the basic inner diameter portion 28 and the basic outer diameter portion 24 is _T50 , and the thin approximately cylindrical portion 35 is provided. Assuming that the average wall thickness is _T35 , the relational expression 0.40 _T50 ≤ _T35 ≤ 0.75 _T50 is established. The stop ring 3 is stationary with the pipe P without rotating. Therefore, it is possible to prevent the occurrence of relative slippage between the sloped surface 5 of the joint body 1 and the pressure contact sloped surface 32 . It is possible to omit the "preliminary processing" using a special jig, which is described as the unsolved problem (i) in the conventional pipe joint (shown in FIG. 18).
Along with this, the work efficiency at the piping connection site is dramatically improved.
Furthermore, the pull-out resistance of the pipe is sufficiently strong due to the double strong pressure contact state of the rear teeth 36B and the front teeth 36F. In addition, such a double press-contact state can prevent rotation of the pipe P about its axis more reliably than the claw portion 61 of the triangular cross-section of the conventional pipe joint (shown in FIG. 18). In particular, the average thickness dimension _T35 of the thin approximately cylindrical portion 35 is sufficiently large as 40% to 75% of the thickness dimension _T50 of the basic short cylindrical portion 50. The rear teeth 36B and front teeth 36F at the tip of the substantially cylindrical portion 35 can be strongly pressed against the pipe outer peripheral surface 10A. Moreover, regardless of the sufficiently large thickness dimension _T35 of the thin-walled substantially cylindrical portion 35, it is possible to sufficiently reduce the rotational torque for screwing the cap nut 2 (experimental results show that ) has become clear. Also, the metal seal performance can be maintained at a sufficiently high level due to the double seal of the rear teeth 36B and the front teeth 36F.

In addition, the present invention has a flare joint body 1 having a male threaded portion 9 and a tapered surface 5 with a reduced diameter at the tip, and a female threaded portion 12 screwed onto the male threaded portion 9 at the proximal end of the hole portion 11, In the middle of the hole 11, there is formed a storage space E having a portion 14 of the same diameter, a stepped portion 15, and a tapered portion 17 with reduced diameter at the tip end. In addition, it has a base-side pressing sloped surface 32 that presses against the tip diameter-reducing sloped surface 5, and a plastically deformable thin-walled substantially cylindrical portion 35 on the tip side and a toothed portion 36 for preventing the pipe from being pulled out of the tip head portion 37. The tooth portion 36 is composed of a rear tooth 36B and a front tooth 36F arranged with a minute gap _W36 , and the cross-sectional shape of the rear tooth 36B is has a substantially trapezoidal shape, and the first tip side 41, which is the upper side of the substantially trapezoidal shape, is separated from the lower rear side 63 and the taller front side by way of the rounded intermediate stepped portion 62. The front tooth 36F has a portion 64, and the cross-sectional shape of the front tooth 36F is substantially trapezoidal. Since it has a polygonal shape with a short rear half side portion 66 and a tall front half side portion 67, it exhibits a double sealing function when the sealed fluid is a gas such as a refrigerant, and high sealing performance is stabilized. obtained by The sloped surface 65 of the front tooth 36F and the tall front side portion 67 easily bite (sink) into the outer peripheral surface 10A of the pipe P, and can reliably prevent the pipe P from coming off. In particular, it is possible to reliably prevent the pipe P from coming off the sloped surface 65 in a situation where a pull-out force acts on the pipe P while a bending force acts on the pipe P near the pipe joint.
In the rear teeth 36B, even if the pipe P rotates, the tall front side portion 64 sinks into the outer peripheral surface 10A of the pipe while forming a small ridge 68, forming a small concave peripheral groove _U64 . , guiding is performed to reduce or prevent helical rotation and meandering rotation of the pipe P, and high sealing performance is maintained.

Further, the first tip side 41 of the rear tooth 36B of the stop ring 3 and the second tip side 42 of the front tooth 36F of the stop ring 3 are aligned with the outer peripheral surface 10A of the straight tip portion 10 of the pipe P to be connected. 2, a strong pressure contact state is created to generate a pipe pull-out resistance force Z. Since the second tip side 42 of 36F is pressed against the outer peripheral surface 10A of the pipe P in a biting manner to perform a double seal function, high sealing performance is achieved when the fluid to be sealed is "refrigerant". can be stably demonstrated.

In addition, the double sealing function is exhibited in a state of strong pressure contact, and since the structure is such that sealing materials are omitted from the inner and outer peripheral surfaces of the stop ring 3, expensive sealing materials such as those for refrigerant resistance are not required. In addition, the sealing performance can be maintained for a long period of time, and the troublesome processing of grooves for sealing in the stop ring 3 can be omitted.

In addition, even if the pipe P rotates around its axis _LP under the strong pressure contact condition, the front side portion 64 of the first tip side 41 of the rear tooth 36B does not touch the outer peripheral surface 10A of the pipe P. It bites so as to form a closed annular small concave peripheral groove U ₆₄ to prevent meandering or spiral rotation of the pipe P. Since it is configured to press against the rear side surface of ₆₄ and exhibit a sealing function, the sealing function of the rounded intermediate stepped portion 62 can also be maintained well (without becoming unstable).

Further, when the rear teeth 36B and front teeth 36F are strongly pressed against the outer peripheral surface 10A of the pipe P, the pipe pullout resistance _ZF of the front teeth 36F is greater than the pipe pullout resistance _ZB of the rear teeth 36B. In addition, the second tip side 42 of the front tooth 36F strongly presses against the outer peripheral surface 10A with the broken line shape to prevent the pipe P from being pulled out due to the external force in the bending direction. Since the function is shared by the front teeth 36F, the front teeth 36F prevent the pipe P from being pulled out even when the pipe P is bent, and the rear teeth 36B always exhibit a good sealing function. , and cooperate with the rear teeth 36B to maintain a stable and high pipe pull-out resistance and sealing performance.

Further, the rear teeth 36B and the front teeth 36F are arranged so that the first tip side 41 and the second tip side 42 are at an equal distance _L36 from the axis _LP of the pipe P under the strong pressure contact state. Since it is configured to bite into the outer peripheral surface 10A of the pipe P to the same depth (as shown in FIG. 15), the rear teeth 36B and the front teeth 36F work together in the best balance to achieve high pipe durability. Pullability and high sealing performance can be exhibited.

In the hole 11 of the cap nut 2, the tapered portion 17 with reduced diameter at the tip is composed of a steep taper portion 17A on the proximal end side, an intermediate gentle taper portion 17B, an intermediate steep taper portion 17C and a gentle taper on the tip end side. Since it is configured with the portion 17D, as described in sequence with reference to FIGS. Fine squeezing can be done. Moreover, even if the average thickness _T35 of the thin cylindrical portion 35 is relatively large and the axial dimension is small (short), the screwing of the cap nut 2 causes the final thickness shown in FIG. It can smoothly transition to the strong pressure contact state. In particular, in the first half of the process shown in FIGS. 8 _to 10, the rear tooth 36B is mainly narrowed down, and in the second half shown in FIGS. It is possible to narrow down to the main. As a result, as shown in FIG. 15, the rear teeth 36B and the front teeth 36F can be evenly bitten into the pipe outer peripheral surface 10A.
Further, by separately providing the proximal steep taper portion 17A and the intermediate steep taper portion 17C, the step of pressing the entire stop ring 3 axially inward can be divided into a plurality of times. By this process of pressing the stop ring 3, the pressure contact gradient surface 32 comes into close contact with the leading end diameter reduction gradient surface 5 of the joint body 1 to form a metal seal (pressure contact). The metal seal (pressure contact) is strengthened little by little while gradually narrowing down to the outer peripheral surface 10A of the pipe.
In this way, it can be said that two different actions in the axial direction--the tightening action of the rear teeth 36B and the front teeth 36F and the metal sealing (pressure contact) action--can be simultaneously advanced in a well-balanced manner.
In addition, the total number of rotations of the cap nut 2 can be reduced due to the presence of the steep tapered portion 17A on the proximal end side. 8, the rear teeth 36B and the front teeth 36F are not in contact with the pipe P immediately after the cylindrical portion 35 starts to be squeezed. Rapidly squeezing the cylindrical portion 35 by the steep taper portion 17A on the end side can reduce the total number of rotations of the cap nut 2, and can be said to be rational.

In the hole 11 of the cap nut 2, the tapered portion 17 with reduced diameter at the tip is composed of a steep taper portion 17A on the proximal end side, an intermediate gentle taper portion 17B, an intermediate steep taper portion 17C and a gentle taper on the tip end side. Further, the tip head portion 37 of the thin-walled substantially cylindrical portion 35 includes a first convex portion 71 consisting of the most distal outer peripheral corner portion and an axial tooth corresponding to the axial position of the rear teeth 36B. and a low triangular hill-shaped second projection 72 formed on the outer periphery of the tip head 37 at the directional position, and the tip head 37 is reduced in diameter as the cap nut 2 is screwed. As it slides into the taper portion 17, the second convex portion 72 is pressed radially inward by the steep taper portion 17A on the proximal end side, and the rear teeth 36B are pressed against the outer peripheral surface 10A of the pipe P. After that, the first convex portion 71 is pressed radially inward by the intermediate steep taper portion 17C to press the front teeth 36F against the outer peripheral surface 10A of the pipe P, the second pressing step. Since it is configured to perform the pressing process, each pressing (pressing) of the rear teeth 36B and the front teeth 36F can be skillfully performed while giving a time difference between the first and second pressings. Moreover, even if the average thickness _T35 of the thin cylindrical portion 35 is relatively large and the axial dimension is small, the cap nut 2 is screwed to reach the strong pressure contact state shown in FIG. , can be transitioned smoothly.
In particular, in the first pressing process in the first half (shown in FIGS. 8 to 10), mainly the rear teeth 36B are pressed in, and in the second pressing process in the latter half (shown in FIGS. 11 to 13), mainly the front teeth are pressed. 36F is pushed in, and as a result, as shown in FIG. 15, the rear teeth 36B and the front teeth 36F can evenly bite (sink) (up to the radial depth position of the dashed line L ₃₆ ). .
Since the squeezing is performed in two steps as the first pushing process and the second pushing process, the rotational torque of the work tool for tightening the cap nut 2 can be reduced (equalized).
In addition, the pressure gradient surface 32 of the stop ring 3 is brought into close contact with the leading end diameter reduction gradient surface 5 of the joint body 1 to form a metal seal (pressure contact). It is convenient because it is strengthened little by little by dividing it into two times.
In other words, a time difference is provided between the first pressing process and the second pressing process, and the pressing action of the rear teeth 36B and the front teeth 36F and the metal sealing (pressure contact) action between the pressure contact slope surface 32 and the slope surface 5 are performed. can be divided into two times with good balance and progressed at the same time. As a result, as shown in FIG. 15, the rear teeth 36B and the front teeth 36F are evenly pushed to the same depth as indicated by the dashed line _L36 , and a large pipe pull-out resistance (Z _B +Z _F ) can be exerted. At the same time, it exhibits excellent sealing performance against refrigerants, etc., due to the metal touch double seal.

In addition, in the tightened state of the cap nut 2, the stepped portion 25 formed by the tip end surface of the basic short cylindrical portion 50 of the stop ring 3 and the stepped portion 15 of the hole portion 11 of the cap nut 2 However, since the worker is able to detect an increase in the spiral resistance of the cap nut 2 due to the abutment, the tightening torque of the work tool such as a wrench or wrench is rapidly increased, and the work is completed (completion of the connection work). ) can be sensed, which is convenient. 15, the arrow _F15 indicates the force vector generated at the moment when the stepped portion 25 collides with the stepped portion 15. As shown in FIG.

In addition, a supporting inner core 83 is attached to support the tip portion 10 of the pipe P from the inner peripheral side while the rear teeth 36B and the front teeth 36F of the stop ring 3 are strongly pressed against the outer peripheral surface 10A of the pipe P. , When the metal material of the pipe P is soft, or when the pipe P has large variations in the outer diameter and wall thickness due to overseas standards, etc., as indicated by the arrow P ₃₆ in FIG. 16 (B), It can be pushed into the rear teeth 36B and the front teeth 36F to support the pipe P so as not to be excessively deformed in the radially inward direction.
In other words, when the pipe P is soft, or when there is a large difference in the dimensional tolerance of the pipe P (according to overseas standards, etc.), or the outer diameter dimension and the pipe wall thickness dimension itself, the supporting inner core 83 can be used. , the pipe joint having the configuration of the present invention can be applied.

REFERENCE SIGNS LIST 1 Flare joint body 2 Cap nut 3 Stop ring 5 Tip diameter reduction slope surface 9 Male screw part
10 straight tip
10A outer circumference
11 hole
12 female thread
14 same diameter
15 Stepped part
17 Tip reduced diameter taper
17A basal side steep taper
17B Intermediate gentle taper
17C Intermediate steep taper
17D tip side gentle taper
25 steps
32 Proximal pressure slope surface
35 Thin almost cylindrical part
36 teeth
36B rear teeth
36F front tooth
37 tip head
41 1st edge
42 2nd edge
62 R-shaped intermediate step
63 Rear side
64 Anterior half
65 sloped surface
66 Rear side
67 Anterior half
71 First convex part
72 Second projection
83 In-core for support E Storage space L ₃₆ dashed line (equidistant from the axis)
_LP pipe axis P pipe
U ₆₄ small groove W ₃₆ minute interval Z Pull-out resistance of pipe Z _B Pull-out resistance by rear teeth Z _F Pull-out resistance by front teeth

Claims (10)

a flare joint body (1) having a male threaded portion (9) and a tapered surface (5) with a reduced diameter at the tip;
A female threaded portion (12) screwed onto the male threaded portion (9) is provided at the proximal end of the hole (11), and a portion (14) of the same diameter is provided in the middle of the hole (11). a cap nut (2) forming a storage space (E) having a stepped portion (15) and a reduced diameter tapered portion (17);
A plastically deformable thin substantially cylindrical portion on the distal end side, which is housed in the storage space (E) and has a base end pressure contact gradient surface (32) in pressure contact with the tip diameter reduction gradient surface (5). a stop ring (3) having (35) and pipe pull-out prevention teeth (36) on its tip head (37);
In a pipe joint equipped with
The tooth portion (36) is composed of a rear tooth (36B) and a front tooth (36F) arranged with a minute interval ( _W36 ),
The rear tooth (36B) has a substantially trapezoidal cross-sectional shape, and the first tip side (41), which is the upper side of the substantially trapezoidal shape, extends from the rear tooth (36B) through the rounded intermediate stepped portion (62). has a low posterior side (63) and a tall anterior side (64),
The cross-sectional shape of the front tooth (36F) is substantially trapezoidal, and the second tip side (42), which is the upper side of the substantially trapezoidal shape, extends from the back through the rearwardly downward inclined surface (65). A pipe joint characterized by a polygonal shape having a low rear side portion (66) and a tall front side portion (67). The first tip side (41) of the rear tooth (36B) of the stop ring (3) and the front tooth (36F ) is brought into a state of strong pressure contact with the screwing of the cap nut (2) to generate a pipe pull-out resistance (Z), and further, the strong pressure contact In this state, the first tip side (41) of the rear teeth (36B) and the second tip side (42) of the front teeth (36F) bite into the outer peripheral surface (10A) of the pipe (P). 2. The pipe joint according to claim 1, which is constructed so as to perform a double-sealing function by pressing against. 3. The pipe joint according to claim 2, wherein the stop ring (3) has no sealing material on the inner peripheral surface and the outer peripheral surface of the stop ring (3), exhibiting the double sealing function in a state of strong pressure contact. Even if the pipe (P) rotates about its axis (L _P ) under the strong pressure contact state, the front side (64) of the first tip side (41) of the rear tooth (36B) is bit into the outer peripheral surface (10A) of the pipe (P) so as to form a closed annular small recessed peripheral groove ( _U64 ) to prevent the helical rotation of the pipe (P). 3. The pipe joint according to claim 2 , wherein the rounded intermediate stepped portion (62) of ) is in pressure contact with the rear side surface of the small concave peripheral groove ( _U64 ) to exhibit a sealing function. When the rear teeth (36B) and the front teeth (36F) are in the strong pressure contact state with respect to the outer peripheral surface (10A) of the pipe (P), the resistance to pulling out the pipe (Z _B ) of the rear teeth (36B) is Along with sharing so that the pipe pull-out resistance (Z _F ) of the front teeth (36F) increases,
The second tip side (42) of the front tooth (36F) strongly presses against the outer peripheral surface (10A) with the broken line shape to prevent the pipe (P) from coming out due to the external force in the bending direction. 3. A fitting according to claim 2 , wherein the function is shared by said front teeth (36F). so that the first tip side (41) and the second tip side (42) are equidistant ( _L36 ) from the axis (L _P ) of the pipe (P) under the strong pressure contact state; 6. A pipe joint according to claim 2, 3, 4 or 5, wherein the rear teeth (36B) and the front teeth (36F) are formed so as to bite into the outer peripheral surface (10A) of the pipe (P) to the same depth. In the hole (11) of the cap nut (2), the tapered portion (17) with reduced diameter at the tip is composed of a steep tapered portion (17A) on the proximal side, an intermediate gentle tapered portion (17B), and an intermediate steep tapered portion (17B). 7. The pipe joint according to claim 1, 2, 3, 4, 5 or 6, comprising a portion (17C) and a gently tapered portion (17D) on the distal end side. In the hole (11) of the cap nut (2), the tapered portion (17) with reduced diameter at the tip is composed of a steep tapered portion (17A) on the proximal side, an intermediate gentle tapered portion (17B), and an intermediate steep tapered portion (17B). Consists of a portion (17C) and a gently sloping tapered portion (17D) on the distal end side,
Further, the tip head portion (37) of the thin-walled substantially cylindrical portion (35) has a first convex portion (71) formed by a tip outer peripheral corner portion and an axial tooth corresponding to the axial position of the rear teeth (36B). a low triangular hill-shaped second protrusion (72) formed on the outer periphery of the tip head (37) at a directional position,
As the cap nut (2) is screwed, the tip head (37) slides into the tip reduced diameter tapered portion (17), and the second convex portion (72) moves into the base. A first pressing step is performed in which the rear tooth (36B) is pressed radially inward by the end-side steep taper portion (17A) to press the outer peripheral surface (10A) of the pipe (P), and then the first pressing step is performed. A second pressing step is performed in which the convex portion (71) is pressed radially inward by the intermediate steep tapered portion (17C) to press the front teeth (36F) against the outer peripheral surface (10A) of the pipe (P). 8. A pipe joint as claimed in claim 1, 2, 3, 4, 5, 6 or 7, adapted to do so. The stop ring (3) has a basic inner diameter portion (28) into which the pipe (P) is inserted, and a basic outer diameter portion (24) that is accommodated in the storage space (E) of the cap nut (2). a stepped portion (25) consisting of a front end surface of a basic short cylindrical portion (50) consisting of the basic inner diameter portion (28) and the basic outer diameter portion (24); and the hole portion of the cap nut (2). Claim that the stepped portion (15) of (11) comes into contact with the cap nut (2) when the cap nut (2) is completely tightened, and the worker can detect an increase in the spiral resistance of the cap nut (2). 9. A pipe joint according to item 1, 2, 3, 4, 5, 6, 7 or 8. The rear teeth (36B) and front teeth (36F) of the stop ring (3) are in the state of strong pressure contact with the outer peripheral surface (10A) of the pipe (P), and the tip (10) of the pipe (P) is pushed to the inner peripheral side. 7. The pipe joint according to claim 2, 3, 4 , 5 or 6 , further comprising a supporting inner core (83) for supporting from.

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