JP2015094462A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint exhibiting large drawing force resistance, easily manufactured, and capable of reducing its cost.SOLUTION: A pipe joint includes a first C-ring 21, and the first C-ring 21 has an inner projection 15 for pipe removing prevention on its inner peripheral surface and a plurality of inclined independent outer projection projecting outward with its outer peripheral surface as an outward large diameter taper surface. The independent outer projection 17 is engaged to an independent inner projection 30 of a second C-ring 24 inside a cap nut 2, and thereby pipe is prevented from being drawn out.

Description

  The present invention relates to a pipe joint.

The present inventors have proposed pipe joints such as those shown in FIGS. 8, 9, and 10 in the past, and have been sold in large numbers mainly for connecting pipes made of plastic pipes for about 10 years. (See Patent Document 1).
This pipe joint has a joint body 42 having an insertion tube portion 50, and the end portion of the plastic pipe 41 inserted while being fitted on the insertion tube portion 50 is tightened with a strong elastic tightening force. A fastening ring 43 with a slit 60 is provided. Then, in the state where the pipe is not inserted, a diameter-enlarging piece that is removably inserted into the slit 60 and held so as to expand the diameter of the clamping ring 43 against the strong elastic force of the clamping ring 43 ( Jump pin) 44.

  The diameter-expanded piece (jump pin) 44 and the tightening ring 43 are formed in the subunit U as shown in FIGS. 9 and 10 in advance (as shown in FIG. 8). Assembled. When the pipe 41 is inserted from the direction of the arrow A in FIG. . Immediately due to this separation, a powerful tightening force in the diameter-reducing direction of the tightening ring 43 acts on the pipe 41, and the inner peripheral surface of the pipe 41 is pressed against the insertion tube portion 50 of the joint body 42, The pipe 41 cannot be pulled out by frictional force. In addition, the O-rings 45 and 45 can provide sealing performance.

Japanese Patent No. 3843288

  Although the pipe joints shown in FIGS. 8 to 10 described above are pipe joints having a stable and large pull-out force and high reliability, they have the following problems. (i) Since the tightening ring 43 is made of spring steel and has a structure that needs to exert a strong elastic tightening force, the diameter expanding piece 44 is pushed into the slit 60 as shown in FIGS. (Ii) Before the sub unit U is assembled to the joint body 42 (as shown in FIG. 8), the diameter expansion piece (jump pin) 44 is unexpectedly (Iii) The tightening ring 43 has a strong elastic force to the pipe 41 inserted with the enlarged diameter piece 44 detached. When tightened, it is required to generate a perfect circular shape and uniform clamping surface pressure over the entire 360 ° circumference. However, since such a uniform tightening surface pressure cannot be obtained, the width dimension of the spring steel must be changed from the slit 60 toward the circumferential direction, Difficult to manufacture, (iv) In addition, in order to reduce the overall size of the joint, the maximum width dimension of the tightening ring 43 is limited. (V) The cost is high because the manufacturing is not easy as described above.

  Therefore, the present invention solves these problems (i) to (v), is easy to manufacture and can be reduced in cost, can exhibit a high pipe pull-out resistance, and can be used after pipe connection is completed. An object of the present invention is to provide a pipe joint that hardly moves in the pulling direction and always exhibits a stable and large pull-out force (prevention force).

  The present invention relates to a pipe joint having a joint body and a cap nut; the inner peripheral surface has a plurality of retaining protrusions that can bite into the outer peripheral surface of the pipe, and the outer peripheral surface is an outwardly enlarged taper surface. A first C-ring having a plurality of independent outer protrusions inclined outwardly on the outer peripheral surface; transmitting the pushing force of the inserted pipe to the first C-ring, and dragging the first C-ring inward of the joint A pulling member; a pipe gripping member integrally molded with plastic; and the pulling member further includes an abutting ring portion that abuts an end surface of the inserted pipe and receives the pushing force; A connecting portion that connects the inner end portion of the 1C ring and the abutting ring portion; and corresponding to the outer diameter-expanding tapered surface of the outer peripheral surface of the first C-ring, A tapered surface on the inner peripheral surface, and the first C-ring The serial independent outside engageable within an isolated ridge to ridge, the second 2C ring a plurality inborn as inclined inwardly and has inside of the cap nut.

Further, a tapered surface that decreases outwardly is formed on the inner peripheral surface of the cap nut; an outer reduced diameter tapered surface that fits the tapered surface of the cap nut is formed on the outer peripheral surface of the second C ring. ing.
Further, the gradient angle of the tapered surface of the inner peripheral surface of the cap nut and the tapered surface of the outer peripheral surface of the second C ring is θ ₂ ; the outwardly enlarged taper surface of the inner peripheral surface of the second C ring; When the gradient angle of the outer diameter-expanded tapered surface of the outer peripheral surface of the first C ring is θ ₁ ; θ ₁ <θ ₂ was set.
Moreover, the connection part of the said drawing-in member consists of a plurality of thin rod-shaped bodies or a plurality of small strips arranged in the axial direction.
Or the connection part of the said drawing-in member consists of thin film bodies.

  According to the pipe joint according to the present invention, all the components can be made of plastic, and each component can be easily mass-produced and can be manufactured easily and inexpensively. When the connection work is completed, the pipe joint and the pipe do not move relative to each other in the axial direction (axial direction) and are strongly connected. In particular, it exerts a strong pull-out resistance against a plastic pipe or a composite pipe having a plastic outer peripheral layer.

It is sectional drawing of the pipe unconnected state which shows one Embodiment of this invention. It is sectional drawing of a pipe connection completion state. It is sectional drawing which shows an example of a pipe holding member. It is sectional drawing which shows the other example of a pipe holding member. It is a cross-sectional view for demonstrating the various Example of the connection part of a drawing-in member. It is explanatory drawing of the angle relationship of main components. It is a perspective view showing an example of the 2nd C ring. It is sectional drawing of the unconnected state which shows a prior art example. It is a front view which shows main parts. It is BB sectional drawing of FIG.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
In the pipe unconnected state of FIG. 1 and the pipe connection completed state of FIG. 2, P is a pipe having at least an outer peripheral surface made of plastic, and as this pipe P, a plastic pipe (resin pipe), or A composite type resin pipe (composite pipe) having a metal layer such as aluminum inside is preferable.
Examples of the plastic used for the pipe P include cross-linked polyethylene. Reference numeral 1 denotes a joint body, and 2 denotes a cap nut.

The joint main body 1 includes an insertion cylinder portion 3 inserted into the end portion of the pipe P, a fixed cylinder portion 4 connected to the proximal end of the insertion cylinder portion 3, and a proximal end of the fixation cylinder portion 4. It is composed of a hexagonal protruding ridge portion 5, a male screw cylinder portion 6, and an outer envelope cylinder portion 7 with a male screw 7 </ b> A that is fixedly integrated with the fixing cylinder portion 4 in an outer fitting manner. Further, the joint body 1 has a hole 11 penetrating along the axis L _1, and the inner diameter of the hole 11 is set slightly small in the vicinity of the insertion tube portion 3.
Two concave circumferential grooves 8 and 8 are formed on the outer peripheral surface of the insertion cylinder portion 3, and an O-ring 9 is fitted into the concave circumferential groove 8 so as to be intimately sealed with the inner peripheral surface of the pipe P. (See FIG. 2).

A stepped portion (step surface portion) 13 is formed on the inner peripheral surface of the outer tube portion 7 at the same axial position as the stepped portion (step surface portion) 12 of the fixed tube portion 4 and the insertion tube portion 3. A space portion C having the attachment portions 12 and 13 as the bottom surface is formed between the inner peripheral surface of the screwed cap nut 2 and outer tube portion 7 and the outer peripheral surface of the insertion tube portion 3.
The cap nut 2 has, on its inner peripheral surface, a female screw 2A at the base end, a tapered surface 2B having a diameter reduced outward, and an inner flange portion 2C (forming an open end) from the inner side to the outer side. We have sequentially toward.
In the description of the present invention, “inward” and “outward” refer to “inward / outward in the radial direction” along the axis L ₁ unless otherwise specified. The direction in which the cap nut 2 is present when viewed from the center of gravity position is referred to as “outward”.

In the space C, a pipe gripping member 20 (see FIG. 3) in which the first C ring 21 and the retracting member 22 are integrally molded with plastic, and the pipe gripping member 20 are externally fitted. A second C-ring 24 assembled in a shape is provided.
The radially outer second C ring 24 is formed with an outer diameter-reduced tapered surface 26 that fits with the tapered surface 2B of the cap nut 2 on the outer peripheral surface 25 thereof. As shown in FIG. 7, the second C-ring 24 is a C-type having a single cut 28 in the circumference, and in the pipe unconnected state (FIG. 1) and the pipe connection completed state (FIG. 2), The inner end face 27 is in contact with the outer end face 7 </ b> B of the outer packet cylinder portion 7. In addition, the second C ring 24 has an outer diameter-expanded taper surface 29 on the inner peripheral surface, and the outer diameter-expanded taper surface 29 has a plurality of independent inner ridges 30 inclined inward. (See FIGS. 6 and 7).

  The pipe holding member 20 will be specifically described with reference to FIGS. The first C ring 21 has a retaining inner protrusion 15 that can bite into the outer peripheral surface 14 of the pipe P on the inner peripheral surface. It is desirable that the inner protrusion 15 for retaining is inclined inward. Further, the first C-ring 21 has an outer peripheral surface as an outwardly enlarged taper surface 16, and has a plurality of independent outer protrusions 17 that are inclined outwardly on the outer peripheral surface (taper surface 16).

Next, the drawing member 22 integrally molded with the first C ring 21 transmits the pushing force F of the pipe P inserted into the space C to the first C ring 21, as shown in FIGS. The first C ring 21 is a portion that is dragged inward of the joint.
Thus, since the pipe holding member 20 is formed by integrally molding the drawing member 22 and the first C ring 21 with plastic, the drawing member 22 and the first C ring 21 are connected to the drawing portion and the first C ring portion. It is also desirable to call it.

Further, the drawing-in part (material) 22 includes an abutting ring part 22A that receives the pushing force F when the end face 18 of the inserted pipe P abuts, a contact ring part 22A, The connecting portion 22B connects the inner end of the 1C ring (portion) 21. The first C-ring (part) 21 has a cut 23 and has a C-shaped cross section, and can be deformed with a reduced diameter, whereas the closed annular contact ring part 22A is not deformed in the radial direction. Therefore, it is preferable to be a shape having a flexibility as connecting portions 22B, FIGS. 1, 2, 3, and FIG. 5 (A), the connecting unit 22B, along the axis L ₁ direction The thin rod-like body 32 is arranged. Or it is set as the small strip board 33 as shown in FIG.5 (C).
Alternatively, as shown in FIGS. 4 and 5B, the connecting portion 22 </ b> B of the retracting member 22 is configured with a thin film body 34. As shown in FIG. 4, it is also possible to form a continuous cut 23A in the cut 23 in the thin film body 34 as the connecting portion 22B. In this case, the axial dimension K of the cut 23A is 50% or more of the axial width dimension N of the thin film body 34. It is also possible to reduce the thickness of the thin film body 34 and eliminate the cut 23A.
Here, another embodiment (not shown) will be described. The contact ring portion 22A can be a C-shaped ring having a cut, and in this case, the first C ring 21 shown in FIG. 3 or FIG. It is desirable to form a cut in the contact ring portion 22A at the same circumferential position as the cut 23 (and the cut 23A). In addition, when the contact ring portion 22A is a C-shaped ring, it is preferable to increase the rigidity by increasing the cross-sectional area.

As shown in FIGS. 1, 2, 6, and 7, the outer diameter-expanding tapered surface 29 of the inner peripheral surface of the second C ring 24 is opposite to the outer diameter-expanding tapered surface 16 of the outer peripheral surface of the first C-ring 21. Correspondingly, it is assembled. The independent outer protrusion 17 of the outer diameter-expanding tapered surface 16 of the first C ring 21 and the independent inner protrusion 30 of the outer diameter-expanding tapered surface 29 of the second C ring 24 are engageable with each other (engageable). ).
The independent outer ridge 17 of the first C ring 21 is inclined outward, and the independent inner ridge 30 of the second C ring 24 is inclined inward, and has a C-shaped cross section having a cut 23. 1, the pipe P is inserted from the state of FIG. 1, the end face 18 hits the contact ring portion 22A, receives the pushing force F, and is dragged inward (taken in) via the connecting portion 22B. When the opening size of the cut 23 is reduced, the diameter of the first C ring 21 is deformed in the direction of reducing the diameter, and the connection is completed as shown in FIG.
In addition, since the independent outer ridge 17 is inclined outward and the independent inner ridge 30 is inclined inward, the pipe gripping member 20 is light when the pipe P is grasped by the hand of an operator. The (first C-ring 21) enters the inside of the pipe joint, and the inner protrusion 15 for retaining prevents biting into the plastic outer surface of the pipe P due to the reduced diameter deformation of the first C-ring 21 and exhibits a strong pull-out resistance. To do. 1 and 2, the second C ring 24 (in principle) is in pressure contact with the inner peripheral surface of the cap nut 2 and is in pressure contact with the outer end surface 7B of the outer tube portion 7. It remains stationary (fixed).

As shown in FIG. 6, the gradient angle between the tapered surface 2B of the inner peripheral surface of the cap nut 2 and the tapered surface 26 of the outer peripheral surface 25 of the second C ring 24 is θ ₂ ; When the gradient angle of the outer diameter-expanded tapered surface 29 on the inner peripheral surface and the outer diameter-expanded tapered surface 16 on the outer peripheral surface of the first C ring 21 is θ ₁ ; θ ₁ <θ ₂ was set.
For example, 3 ° ≦ θ ₁ ≦ 7 ° and 8 ° ≦ θ ₂ ≦ 12 °. In particular, by setting 4 ° ≦ θ ₁ ≦ 6 °, it is possible to lightly push the first C-ring 21 even if the pipe pushing force F of the worker is small --- drawing by the drawing member 22-- The tightening force in the radial inward direction also increases to provide a strong pull-out force, and pipe connection work can be done easily and quickly.
As the above-mentioned pipe pushing force F, about 15 kg to 25 kg which is a normal force of the worker is sufficient.

When a normal pulling force is applied to the pipe P, the pipe joint according to the present invention has an advantage that the pipe P is stationary (fixed) in the connection completion state of FIG.
However, in some cases, an excessive pulling force may act on the pipe P in the event of an earthquake or some kind of accident, but when such an excessive pulling force acts, the pipe P and the pipe holding member 20 The second C-ring 24 moves slightly outward (withdrawal direction) as a result of interlocking of the protrusions 15, 17, and 30, but the second C-ring 24 having the cut 28 as shown in FIG. The taper surface 26 is squeezed while strongly pressing against the taper surface 2B of the cap nut 2, and the mutual locking force of the above-mentioned protrusions 30, 17, 15 increases rapidly, and the pipe P is securely held (gripped). It cannot be pulled out any further. In particular, as described with reference to FIG. 6, since θ ₂ > θ ₁ is set, if the second C-ring 24 moves slightly outward, the above-described mutual locking force increases, and a strong pipe Demonstrates pull-out resistance.
As the protrusions 15, 17, and 30, a triangular mountain shape that is inclined outward or inward as in the illustrated embodiment is desirable. The protrusions 17 and the protrusions 30 that are locked to each other are independent protrusions, and have the same pitch and cross-sectional shape. However, the retaining inner ridge 15 that bites into the outer peripheral surface 14 of the pipe P and is locked can be freely formed in a spiral shape (not limited to the illustrated independent ridge).

  The structure and shape of the pipe joint according to the present invention (except for the O-rings 9 and 9) can be made of plastic and have a structure and shape, and as shown in FIG. The strong elastic tightening force (elastic force) described with reference to FIGS. 9 and 10 does not act between the components, and the operator can perform the assembly work very easily. Moreover, there is no danger of one of the parts popping out.

By the way, the shape of the joint main body 1 (excluding the outer tube part 7) of the embodiment of the present invention shown in FIGS. 1 and 2 is exactly the same as that of the joint main body 42 shown in FIG. There is also an advantage that the molding die can be shared as it is.
The pipe P applied to the present invention may be a whole plastic pipe or a composite plastic pipe having a metal reinforcing layer inside.

  Next, in the piping work site, the tip surface 18 of the pipe P may be cut obliquely (not in a shape orthogonal to the axial center). Assuming that the front end surface 18 cut obliquely is pushed in direct contact with the first C ring 21 where the cut 23 exists, the mutual positions in the axial direction of both ends of the cut 23 of the first C ring 21 are assumed. However, a slight deviation occurs inwardly and outwardly--twisting--so that the independent outer ridge 17 of the first C ring 21 slightly deforms in a spiral direction, and the second C It is impossible to accurately lock the independent inner protrusion 30 of the ring 24. As described above, if the both protrusions 17 and 30 are not accurately locked, when the pipe pulling force is applied, slipping occurs between the both protrusions 17 and 30 (both tapered surfaces 16 and 29). A problem that the pull-out force decreases is predicted.

In the present invention, it is the closed ring-shaped (or C-shaped ring with increased rigidity) contacted with the obliquely cut tip surface 18 described above. A posture close to the axial orthogonal plane is maintained, and the inward pulling force of the contact ring 22A is such that a plurality of thin rods 32 or a plurality of small strips 33 ((A of FIG. 3 and FIG. ) (See (C)) or thin film body 34 (see (B) in FIGS. 4 and 5), the pulling force of the contact ring portion 22A is evenly transmitted to the first C ring 21 over 360 °, The first C ring 21 maintains the axial center orthogonal plane posture, and the independent outer ridge 17 and the independent inner ridge 30 are accurately locked to each other.
Further, the first C-ring 21 is reduced in diameter, and the ridges 15 bite into the outer peripheral surface 14 of the pipe P. However, the inner ring-shaped abutting ring portion against the above-mentioned reduced-diameter deformation of the first C-ring 21. 22A does not change in the radial direction, and radial distortion occurs between the first C ring 21 and the contact ring portion 22A. This distortion is caused by a plurality of thin rod-like bodies 32 or small strips 33 (see FIGS. 3 and 5 (A) and (C)) or a thin film body 34 (see FIGS. 4 and 5 (B)). Absorbed, relaxed. Accordingly, the first C-ring 21 can be smoothly reduced in diameter while maintaining a normal posture during inward movement (from FIG. 1 to FIG. 2).

As described above, the present invention is a pipe joint including the joint body 1 and the cap nut 2; the inner peripheral surface has a plurality of retaining inner protrusions 15 that can bite into the pipe outer peripheral surface 14, A first C ring 21 having a plurality of independent outer ridges 17 inclined outwardly on the outer peripheral surface with the outer peripheral surface being an outwardly enlarged taper surface 16; and the pushing force F of the inserted pipe P is the first C A pull-in member 22 that transmits to the ring 21 and drags the first C-ring 21 inward of the joint; a pipe gripping member 20 that is integrally molded from plastic; and further, the pull-in member 22 is inserted An abutting ring portion 22A that receives the pushing force F when the end surface 18 of the pipe P abuts, and a connecting portion 22B that connects the inner end portion of the first C ring 21 and the abutting ring portion 22A. And corresponding to the outer diameter-expanded tapered surface 16 of the outer peripheral surface of the first C ring 21 A plurality of independent inner ridges 30 that have an outer diameter-expanding tapered surface 29 on the inner peripheral surface and that can be engaged with the independent outer ridges 17 of the first C ring 21 are inclined inward. Since the second C-ring 24 is provided inside the cap nut 2, the problems (i) to (v) described with reference to FIGS. Is easy, can eliminate the dangers during manufacturing, and can reduce costs. In particular, the pipe pull-out resistance is also great, and the pipe P does not move in the pull-out direction (outward) after the completion of the pipe connection, and exhibits a large pull-out resistance.
In particular, the pipe gripping member 20 is an integral molding of plastic and can be easily assembled into the space in the cap nut 2. Further, when the first C ring 21 is retracted inward, the first C ring 21 having the cut 23 is deformed in a diameter-reduced manner in a plane orthogonal to the axial center without being twisted, so that the outer diameter is increased. The outer protrusion 17 of the surface 16 and the inner protrusion 30 of the second C ring 24 are securely locked to each other.

Further, a taper surface 2B that shrinks outward is formed on the inner peripheral surface of the cap nut 2; an outer contraction that fits the taper surface 2B of the cap nut 2 is formed on the outer peripheral surface 25 of the second C ring 24. Since the diameter tapered surface 26 is formed, when an excessive pulling force acts on the pipe P in the event of an earthquake or an accident, the pipe P can be prevented from being pulled out with a strong pulling force.
The gradient angle between the tapered surface 2B of the inner peripheral surface of the cap nut 2 and the tapered surface 26 of the outer peripheral surface 25 of the second C ring 24 is θ ₂ ; the outward expansion of the inner peripheral surface of the second C ring 24 When the inclination angle of the diameter taper surface 29 and the outer diameter expansion taper surface 16 of the outer peripheral surface of the first C ring 21 is θ ₁ ; θ ₁ <θ ₂ is set. If it is pushed inward, it is inserted into the pipe joint with a relatively small force and can be removed. On the other hand, when a large pulling force acts on the pipe P due to an earthquake or an accident after the connection is completed, a strong pulling force is generated by the large gradient angle θ ₂ .

Further, the connecting portion 22B of the retracting member 22 is composed of a plurality of thin rod-like bodies 32 or a plurality of small strip plates 33 arranged in the axial direction (closed ring shape or C-shaped ring shape). The first C ring 21 can be reduced in diameter regardless of whether or not the contact ring portion 22A is reduced in diameter (almost), so that the outer peripheral surface 14 of the pipe can be securely held, and the first C ring 21 can be twisted. Does not occur.
Further, since the connecting portion 22B of the pull-in member 22 is made of a thin film body 34, plastic molding of the pipe gripping member 20 is facilitated, and a contact ring portion 22A (closed ring shape or C-shaped ring shape) is provided. Regardless of (almost) reduced diameter deformation, the first C-ring 21 can be freely reduced in diameter, the first C-ring 21 can reliably grip the pipe outer peripheral surface 14, and the first C-ring 21 can be twisted. do not do.

1 Joint body 2 Cap nut 2B Tapered surface
14 Outer surface
15 Inner protrusion for retaining
16 Outward expansion taper surface
17 Independent protrusion
18 (front) end face
20 Pipe gripping member
21 1st C-ring
22 Retractable material
22A Contact ring
22B connecting part
24 2nd C-ring
25 Outer surface
26 Tapered surface
29 Outer diameter taper surface
30 Independent Strike
32 Thin rod
33 Small strip
34 Thin film body F Pushing force P Pipe θ ₁ , θ ₂ Gradient angle

A stepped portion (step surface portion) 13 is formed on the inner peripheral surface of the outer tube portion 7 at the same axial position as the stepped portion (step surface portion) 12 of the fixed tube portion 4 and the insertion tube portion 3. A space portion C having the attachment portions 12 and 13 as the bottom surface is formed between the inner peripheral surface of the screwed cap nut 2 and outer tube portion 7 and the outer peripheral surface of the insertion tube portion 3.
The cap nut 2 has, on its inner peripheral surface, a female screw 2A at the base end, a tapered surface 2B having a diameter reduced outward, and an inner flange portion 2C (forming an open end) from the inner side to the outer side. We have sequentially toward.
In the description of the present invention, “inward” and “outward” refer to “inward / outward in the axial direction” along the axis L ₁ unless otherwise specified. The direction in which the cap nut 2 is present when viewed from the center of gravity position is referred to as “outward”.

Claims (5)

In pipe fittings with fitting body (1) and cap nut (2),
The inner peripheral surface has a plurality of retaining protrusions (15) that can bite into the outer peripheral surface of the pipe (14), and the outer peripheral surface has an outwardly enlarged taper surface (16) that is inclined outwardly on the outer peripheral surface. A first C-ring (21) having a plurality of independent outer protrusions (17),
A pull-in member (22) that transmits the pushing force (F) of the inserted pipe (P) to the first C-ring (21) and drags the first C-ring (21) inward of the joint;
It is equipped with a pipe gripping member (20) that is integrally molded from plastic,
Furthermore, the drawing member (22) includes an abutting ring portion (22A) that receives the pushing force (F) when the end surface (18) of the inserted pipe (P) abuts, and the first C ring (21 A connecting portion (22B) for connecting the inner end portion of the contact ring portion (22A),
Moreover, corresponding to the outer diameter-expanded tapered surface (16) of the outer peripheral surface of the first C ring (21), the outer diameter-expanded tapered surface (29) is provided on the inner peripheral surface, and the first C A second C ring (24) having a plurality of independent inner ridges (30) that can be engaged with the independent outer ridges (17) of the ring (21) in an inwardly inclined shape is formed on the cap nut (2). A pipe joint characterized by having it inside. A tapered surface (2B) is formed on the inner peripheral surface of the cap nut (2), the diameter of which decreases outward,
The outer peripheral surface (25) of the second C ring (24) is formed with an outer diameter-reduced tapered surface (26) that fits into the tapered surface (2B) of the cap nut (2). Pipe fittings. The gradient angle between the tapered surface (2B) of the inner peripheral surface of the cap nut (2) and the tapered surface (26) of the outer peripheral surface (25) of the second C ring (24) is (θ ₂ ),
The gradient angle between the outer diameter-expanded tapered surface (29) of the inner peripheral surface of the second C ring (24) and the outer diameter-expanded tapered surface (16) of the outer peripheral surface of the first C ring (21) is (θ ₁ )
The pipe joint according to claim ₂ , wherein θ ₁ <θ ₂ is set.   The pipe joint according to claim 1, wherein the connecting portion (22B) of the retracting member (22) comprises a plurality of thin rod-like bodies (32) or a plurality of small strips (33) arranged in the axial direction. .   The pipe joint according to claim 1, wherein the connecting portion (22B) of the drawing member (22) comprises a thin film body (34).

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