JP7126213B2 - 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 three points remain unsolved 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, and only locally plastically deforms the pipe P in the inner diameter direction, and the pipe pull-out resistance is small.
(iii) As described in (ii) above, the claws 61 do not bite into the pipe P, and when an external force is applied to rotate the pipe P around its axis after completion of the piping work, the pipe P easily rotates. Along with this, the metal seal between the claw portion 61 and the outer peripheral surface of the pipe is destroyed. Therefore, the O-ring 58 cannot be omitted.

Accordingly, the present invention provides a pull-out preventing pull-out prevention pull-out prevention pull-out prevention pull-out prevention pull-out prevention pull-out pull-out prevention pull-out prevention pull-out type pull-out preventing pull-out prevention pull-out prevention pull-out prevention pull-out pull-out prevention member that is strongly pressed against the outer peripheral surface of a pipe to be connected as the cap nut is screwed into the male threaded portion of the joint body. A tooth portion is provided integrally with the joint body itself, and the pulling-out prevention is provided at the tip of a thin-walled substantially cylindrical portion that is continuously provided in a protruding manner from the tip end surface of the connection tube portion that has the male screw portion on the outer periphery. A tooth portion is formed, and the tooth portion is composed of a rear tooth and a front tooth that are arranged with a minute interval therebetween, and the cross-sectional shape of the rear tooth is substantially trapezoidal, and the upper side of the substantially trapezoidal shape. has a short rear half side portion and a tall front half side portion through a rounded intermediate stepped portion, and the cross-sectional shape of the front teeth is substantially trapezoidal, and , the second tip side, which is the upper side of the substantially trapezoidal shape, is in the form of a polygonal line having a low rear half side portion and a tall front half side portion via a rearwardly downward inclined surface.

Further, the first tip end side of the rear tooth of the joint body and the second tip end side of the front tooth of the joint body are strongly attached to the outer peripheral surface of the straight end 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 joint main body so as to exhibit the above-mentioned 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. In addition, the rounded intermediate stepped portion of the first tip side presses against 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 front tooth shares the function of preventing the pipe from being pulled out by strongly pressing the second tip side of the pipe against the outer peripheral surface with the bent line shape to prevent 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.
In addition, in the hole of the cap nut, the tapered portion with reduced diameter at the tip is composed of a steep tapered portion on the proximal side, an intermediate gentle tapered portion, and an intermediate steep tapered portion and a gentle tapered portion on the distal end side. .

Further, in the hole portion of the cap nut, the tip diameter reducing taper portion is composed of a base end steep taper portion, an intermediate gentle taper portion, and an intermediate steep taper portion and a tip gentle taper portion, 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 first convex portion and the rear teeth. and a low triangular hill-shaped second convex portion, and as the cap nut is screwed, the tip head slides into the tip diameter-reduced tapered portion, the second convex portion is pressed radially inward by the proximal-side steeply tapered portion to perform a first pressing step of pressing the rear teeth against the outer peripheral surface of the pipe, and then the first convex portion is pushed into the intermediate steeply tapered portion. It is configured to perform a second pressing step of pressing the front tooth against the outer peripheral surface of the pipe by being pressed radially inward by the portion.

Further, a stepped portion is formed in the hole of the cap nut, and when the cap nut is completely tightened, the front end surface of the cap nut connecting tubular portion of the joint body and the stepped portion of the cap nut are connected. However, it is configured so that the operator can detect an increase in screw resistance of the cap nut by contacting it .

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.

1 is a cross-sectional view showing an embodiment of the present invention and showing a state in the middle of pipe connecting work; FIG. 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. FIG. 4 is a cross-sectional view of essential parts of an embodiment of a joint body; Fig. 4 is an enlarged cross-sectional view of a main part of the joint main body; 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 explanatory diagram showing a strong pressure contact state, (A) being an enlarged cross-sectional explanatory diagram of a main part, (B) being a partially non-cross-sectional explanatory diagram showing a further enlarged main part of (A), and (C). FIG. 4 is a partially non-cross-sectional explanatory diagram showing the main part of (A) further enlarged; 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. 10 is a cross-sectional view showing a conventional example; FIG. 10 is a 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, the pipe joint J according to the present invention comprises a joint body 1 and a cap nut 2, and furthermore, the end of the pipe P to be connected (conventional flare processing) completely omitted) has a straight tip 10 .

The joint body 1 has a straight shape as a whole, and is provided with a passage hole 6 extending along its axis. A holding portion 1A is provided, and connecting cylinder portions 7, 7 are continuously provided in the lateral direction of the axis. A male screw portion 9 is formed on the outer peripheral surface of each connecting tube portion 7 . Two cap nuts 2, 2 are screwed onto the left and right male screw portions 9, 9. As shown in FIG.

As shown in FIGS. 1 and 4, a thin substantially cylindrical portion 35 extends integrally from the distal end surface 7A of the connecting tubular portion 7. As shown in FIGS. In other words, it has a connecting tube portion 7 having a male screw portion 9 on its outer peripheral surface, and a thin substantially cylindrical portion 35 connected to the tip side (via a tip surface 7A as a stepped portion).

In addition, the flow path hole (hole) 6 has a stepped portion 30, and the diameter of the left and right outer portions is larger than the central basic diameter, and the pipe P extends to this stepped portion 30 (or to the vicinity thereof). inserted. In this way, the (slightly) large-diameter pipe insertion hole 28 formed with the stepped portion 30 has a rear part 31 formed in a tapered shape with a reduced diameter at the rear (explained earlier) so that the pipe can be inserted. It is formed so that the outer peripheral surface 10A of the pipe is in pressure contact with the inner peripheral surface 27 of the hole 28 in the completed state (see FIG. 2).

As shown in FIG. 4, the inner diameter of the proximal end of the thin substantially cylindrical portion 35 is matched with the inner diameter of the distal end of the pipe insertion hole 28, and the inner peripheral surface of the thin substantially cylindrical portion 35 has a shape of has a tapered shape that gradually expands in diameter toward the distal end (see angle θ1 in FIG. ₅ ).
Further, the inner peripheral surface of the tip head portion 37 of the thin-walled substantially cylindrical portion 35 is provided with a pull-out prevention tooth portion 36 . As shown in the enlarged cross section of FIG. 5, the tooth portion ₃₆ is composed of a rear tooth 36B and a front tooth 36F arranged with a minute gap W36.
As described above, in the pipe joint according to the present invention, the joint body 1 itself has the pull-out prevention tooth portion 36 --- the rear teeth 36B and the front teeth 36F ---- which exert the pipe pull-out resistance force.

By the way, in FIGS. 1 and 2, the overall shape is illustrated as being straight, but it can be any shape such as T-shape, Y-shape, cross-shape, elbow-shape, or the like. 1 and 2 illustrate the case where the thin approximately cylindrical portion 35 is provided at both end portions for connection, but this unique thin approximately cylindrical portion 35 is provided only at one end, and the other end is provided with a tapered male thread or a parallel thread. A connecting structure having a female screw or a welding tube may be used freely.

As shown in FIGS. 1 to 3, the cap nut 2 is provided with a hole portion 11 penetrating in the axial direction, and a female screw portion to which the male screw portion 9 is screwed at the base end of the hole portion 11. 12, and from this female threaded portion 12 toward the tip, in order, an escape groove 13 with a small width, a stepped portion 15, a short straight portion 16 with a small width W ₁₆ , a tapered portion 17 with a reduced diameter at the tip, and ( A straight portion 18 having an inner diameter slightly larger than the outer diameter of the pipe P to be connected 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. A metal seal Ms (see FIG. 2) is formed between the proximal end portion of the cap nut 2 and the vicinity of the distal end surface of the gripping portion 1A of the joint body 1 by press-contacting the metal to each other while the cap nut 2 is being screwed. Therefore, the sealing material is omitted. The cap nut 2 is made of brass or aluminum.
The reduced-diameter tapered portion 17 at the distal end is configured as follows. That is, as shown in FIG. 3(B), the tip reduced diameter taper portion 17 includes a base end steep taper portion 17A, an intermediate gentle taper portion 17B, an intermediate steep taper portion 17C and a tip gentle taper portion. It consists of 17D, etc.

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.

4(A) and 5, if the average thickness dimension of the thin cylindrical portion ₃₅ is T35 and the average thickness dimension of the connecting cylinder portion ₇ is T7, then 0.40· The thickness dimension T ₃₅ of the thin substantially cylindrical portion 35 is formed relatively thick so that T ₇ ≦T ₃₅ ≦0.75·T ₇ (Formula 1) is established.
In addition, in FIG. 5, the average wall thickness dimension _T35 is calculated excluding the front tooth 36F and the rear tooth 36B, which are partitioned by dotted lines _LF and _LB. Furthermore, since the connecting tube portion 7 has a male threaded portion (peaks and valleys) on its outer periphery, the thickness varies at each position in the axial direction, but the average value thereof can be calculated. to find the _average wall thickness dimension T7.

Thus, in the present invention, the average thickness dimension T35 of the thin-walled substantially cylindrical portion ₃₅ is set sufficiently large to be 40% to 75% of the thickness dimension T7 of the connecting tube portion ₇ . .
It should be noted that it is preferable to set 0.43·T ₇ ≦T ₃₅ ≦0.65·T ₇ (formula 2).
Further, it is desirable to set 0.45·T ₇ ≤ T ₃₅ ≤ 0.55·T ₇ (equation 3).
In the above formula, if the value is less than the lower limit, it is difficult for the thin substantially cylindrical portion 35 to withstand the internal pressure. Conversely, when the upper limit is exceeded, the step size of the (stepped) end surface 7A 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 be able to reliably and smoothly bite into (restrict) the outer peripheral surface 10A of the pipe P as shown in FIGS. 8 to 15 (to be described later). .

As shown in FIGS. 4 and 5, the tooth portion ₃₆ is composed of a rear tooth 36B and a front tooth 36F arranged with a minute interval W36. In the present invention, the front teeth 36B and front teeth 36F are referred to by viewing the tip (right) direction in FIGS. 4 and 5 as "forward".

As shown in FIGS. 6(D) and 5, the cross-sectional shape of the rear teeth 36B is substantially trapezoidal, and the first edge 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 side portion 66 and a tall front side portion 67 via a sloped surface 65 inclined backward and downward. shape. (This front side portion 67 may be referred to as the front end portion 42A.) 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, and under the free state, as shown in FIG. The front end portion 42A (front half side portion 67) of 42 is provided slightly radially outward from the first front end side 41 of the rear tooth 36B. That is, in a state where the first tip side 41 of the rear tooth 36B is in contact with the straight line L30 parallel to the axis L1 ₍ see FIG. 4) of the joint body ₁ , 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 cylindrical portion 35, the dimension (radius) of the second tip side 42 is slightly larger than the dimension (radius) of the _first tip side 41 from the pipe axis L1.
That is, the first tip side 41 and the second tip side 42 have _a difference in dimension from the pipe axis L1.

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 reduced-diameter tapered portion 17 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 cylindrical straight portion 74, a low triangular hill portion of the second convex portion 72, and an inclined portion whose diameter is reduced in the distal direction from the rounded portion 73 on the inner end side of the tip surface 7A. 75 and 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 62 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 65 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 a strong pressure contact state, a sealing material such as an O-ring is placed on the joint body 1 (as shown in FIG. 1). A sealing material can be omitted from the inner and outer peripheral surfaces of the .

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.

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. Under the condition that the front first convex portion 71 abuts on the intermediate steep tapered portion 17C, the tip head portion ₃₇ is rotationally deformed as indicated by an 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 tip surface 7A 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 front end surface 7A of the connecting tube portion 7 of the joint body 1 and the stepped portion 15 of the cap nut 2 come into contact with each other, increasing the screw resistance of the cap nut 2. can be detected by the operator (by hand).

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. FIGS. 16A and 16B show states corresponding to FIGS. 1 and 2, respectively, and the same reference numerals as those of 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, as the cap nut 2 is screwed onto the male threaded portion 9 of the joint body 1, it is strongly pressed against the outer peripheral surface of the connected pipe P, and the pipe pullout resistance Z is reduced. The pull-out preventing tooth portion 36 is formed integrally with the joint main body 1 itself, and a thin-walled approx. The pull-out prevention tooth portion 36 is formed at the tip of the cylindrical portion 35. The tooth portion ₃₆ is composed of a rear tooth 36B and a front tooth 36F arranged with a minute interval W36. _T35 is the _average thickness of the connecting tube portion ₇ , and _T7 is the average thickness of the connecting tube portion ₇ . , the thin cylindrical portion 35 does not rotate (co-rotate) at all when the cap nut 2 is screwed, thus solving the unsolved problem ( The "preliminary processing" using a special jig described as i) can be omitted.
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 T ₃₅ of the thin approximately cylindrical portion 35 is sufficiently large as 40% to 75% of the average thickness dimension T ₇ of the connecting tubular portion 7. 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 number of parts is reduced, the risk of losing small parts is eliminated, and the size in the axial direction is reduced, making it possible to achieve compactness. Also, the number of places where fluid leaks occurs is reduced, and the sealing performance can be improved.

According to the present invention, as the cap nut 2 is threaded onto the male threaded portion 9 of the joint body 1, it is strongly pressed against the outer peripheral surface of the pipe to be connected P to generate the pipe pull-out resistance Z. A blocking tooth portion 36 is integrally formed with the joint body 1 itself, and a thin-walled substantially cylindrical portion 35 protrudes continuously from the distal end surface 7A of the connecting tube portion 7 having the male screw portion 9 on the outer periphery. The pull-out preventing tooth portion 36 is formed at the tip of the tooth portion 36. The tooth portion ₃₆ is composed of a rear tooth 36B and a front tooth 36F arranged with a minute interval W36. The cross-sectional shape of the rear tooth 36B is The first tip side 41, which has a substantially trapezoidal shape and is composed of the upper side of the substantially trapezoidal shape, has a lower rear half side portion 63 and a taller front half side portion 64 with a rounded intermediate stepped portion 62 interposed therebetween. 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 sloped surface 65 inclined backward and downward. Since it has a polygonal shape with a low rear half side portion 66 and a tall front half side portion 67, when the sealed fluid is a gas such as a refrigerant, a double sealing function is exhibited and high sealing performance is stably obtained. be done. 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 joint body 1 and the second tip side 42 of the front tooth 36F of the joint body 1 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 above-mentioned double sealing function is exhibited in a state of strong pressure contact, and sealing materials are omitted from the inner and outer peripheral surfaces of the joint body 1, so expensive sealing materials such as refrigerant-resistant ones can be omitted. As a result, the sealing performance is stably maintained over a long period of time. In addition, it is possible to omit the troublesome processing of grooves for sealing in the joint body 1 .

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 stably maintain 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.
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, in the tightened state of the cap nut 2, the front end surface 7A of the cap nut connection cylinder portion 7 of the joint body 1 and the stepped portion 15 of the hole portion 11 of the cap nut 2 come into contact with each other. As a result, the operator can detect an increase in the spiral resistance of the cap nut 2, so that the tightening torque of the work tool such as a wrench or wrench suddenly increases, and the completion of the connection work (completion of connection work) can be sensed. It is convenient to be able to In FIG. ₁₅ , arrow F15 indicates the force vector generated at the moment when the tip end surface 7A hits 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 joint body 1 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 main body 2 cap nut 7 connecting tube portion 7A tip surface 9 male threaded portion
10 straight tip
10A outer circumference
11 hole
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
35 Thin almost cylindrical part
36 teeth
36B rear teeth
36F front teeth
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 L for support ₃₆ dashed line (equidistant from 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 (9)

As the cap nut (2) is screwed onto the male threaded portion (9) of the joint body (1), it is strongly pressed against the outer peripheral surface of the pipe to be connected (P), and the pipe pullout resistance ( The joint body (1) itself has a pulling-out preventing tooth portion (36) for generating Z) integrally therewith, and the tip end face of the connecting tube portion (7) having the male screw portion (9) on the outer periphery. The pull-out prevention tooth portion (36) is formed at the tip of the thin-walled substantially cylindrical portion (35) that protrudes continuously from (7A),
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). It is polygonal with a low rear half (66) and a tall front half (67)
A pipe joint characterized by : The first tip side (41) of the rear tooth (36B) of the joint body (1) 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 joint body (1) has no sealing material on the inner and outer peripheral surfaces of the joint body (1), exhibiting the double sealing function in a state of strong pressure contact . Even if the pipe (P) rotates around 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). 2. The pipe joint according to claim 1, wherein the rounded intermediate step portion (62) of ) is in pressure contact with the rear side surface of the small concave circumferential groove (U ₆₄ ) to exhibit a sealing function. In the strong pressure contact state, the rear teeth (36B) and the front teeth (36F) with respect to the outer peripheral surface (10A) of the pipe (P) are stronger than the pipe pullout resistance (Z B ) _of the rear teeth (36B). Along with sharing so that the pipe pullout 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. 2. A fitting according to claim 1, 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 _; A pipe joint according to claim 1, 2, 3, 4 or 5, wherein the rear teeth (36B) and the front teeth (36F) are configured 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. 7. A pipe joint according to claim 1, 2, 3, 4, 5 or 6, comprising (17C) and a gently sloping 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. (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) includes a first convex portion (71) consisting of a distal end outer peripheral corner portion and an axial direction 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 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 . A stepped portion (15) is formed in the hole (11) of the cap nut (2), and when the cap nut (2) is completely tightened, the cap nut connection tubular portion (7) of the joint body (1) is ) and the stepped portion (15) of the cap nut (2) are in contact with each other, so that an operator can detect an increase in screw resistance of the cap nut (2). 9. A pipe joint according to item 1, 2, 3, 4, 5, 6, 7 or 8 .

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