JP2020070870A - Pipe joint - Google Patents

Abstract

To provide a pipe joint that prevents corrosion (chemical deterioration) of a seal material by adding a simple small component.SOLUTION: While a pipe is not inserted, a thin plate ring (20) of an orthogonal surface shape to an axis (L) of a hole portion (2A) is provided at a hole portion (2A) of a joint body (2), and is arranged closer to a pipe join inner side (N) than a seal material (10). As a pipe (P) is inserted, the thin plate ring (20) automatically becomes a J-shape.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pipe joint.

Conventionally, pipe joints having various configurations have been used for hot water supply pipes and the like.
For example, the conventional pipe joint shown in FIG. 13 has been proposed by the present applicants and is popular in the market (see Patent Document 1).
That is, when the cylindrical retainer 41 having the tapered male screw portion 41A is screwed in, the continuous beads 43 rotatably embedded in the retainer 41 bite into the surface of the pipe 45 while forming a spiral groove, The pipe 45 can be connected to the joint body 46 so as not to be pulled out.

The joint body 46 is composed of a fixed portion 48 having a through hole portion, and a short tubular body 44 rotatably connected to one end of the fixed portion 48 via a retaining ring 47. The short cylindrical body 44 is formed with a taper female screw portion 44A.
The pipe 45 is inserted into the hole of the joint body 46 (as shown in FIG. 13), but the O-ring (sealing material) 50 provided in the hole of the joint body 46 is attached to the outer peripheral surface of the pipe 45. It is a structure that closely prevents the leak of the sealed fluid such as hot water and water.

Japanese Patent No. 3568904

However, when the pipe joint described in Patent Document 1 (FIG. 13) is used as a pipe joint for hot water supply piping for several months to several years, the O-ring 50 has an outer surface (as shown in the enlarged view of FIG. 14). It was found that there is a possibility that a defective portion G may be generated and an external leakage accident may occur.
Therefore, an object of the present invention is to reliably prevent external leakage of such a pipe joint for hot water supply piping with a simple and inexpensive structure.
Furthermore, many pipe joints (including the above-mentioned Patent Document 1) according to the recent patented invention, which can significantly improve the work efficiency at the pipe connection work site, reduce reliability due to the occurrence of the above-mentioned external leakage accident, and are widely used. It is also an object to improve / solve the delay in using a simple and inexpensive configuration.

  The pipe joint according to the present invention is a pipe joint in which a pipe sealing hole portion of a pipe joint body is provided with a rubber sealing material that is in close contact with an outer peripheral surface of the pipe and prevents external leakage of a sealed fluid. A thin plate ring is arranged in the hole in a plane orthogonal to the axis of the hole in a state where the pipe is not inserted, and moreover, in the inner side of the pipe joint body in which the sealed fluid flows rather than the sealing material. The thin plate ring is disposed, and the inner peripheral edge of the thin plate ring has a pointed cross-section with a reduced thickness dimension in the radial inward direction; The thin plate ring reduces or blocks contact of the rubber-deteriorating gas mixed in the sealed fluid with the sealing material when the connection is completed and elastically deforms inward in a J-shape. It is configured to do.

Further, a concave peripheral groove having a rectangular cross section for mounting the sealing material is provided in the hole portion of the pipe joint body, and a first side surface of the concave peripheral groove that is closer to the inner side of the pipe joint body, and the seal. The thin plate ring is interposed between the material and the material.
Further, at the corners formed by the first side surface of the concave circumferential groove and the pipe insertion hole, the inner peripheral edge of the thin plate ring is allowed to elastically deform in a J-shaped cross section, and is excessive. A chamfer is formed to prevent elastic deformation.

According to the present invention, with a thin plate ring having a simple cross-sectional shape, it is possible to reduce or block contact of a small amount of rubber-deteriorating gas in a sealed fluid with a rubber-made sealing material, thereby chemically degrading the sealing material ( Corrosion) can be prevented and external leakage of the sealed fluid (for a long period of time) can be prevented.
Moreover, the thin plate ring having a simple cross-sectional shape can be easily and inexpensively manufactured by injection molding or machining. In addition, in order for such a thin plate ring having such a simple shape to be deformed into a J-shaped cross section that most effectively seals the sealed fluid, a pipe may simply be inserted.

FIG. 3 is a cross-sectional view of a semi-main part in a connection completed state showing an embodiment of the present invention. It is a principal part expanded sectional view which shows a pipe uninserted state. It is a principal part expanded sectional view which shows the pipe intermediate state. It is a principal part expanded sectional view which showed the state of the completion of connection and the state before pressure reception. A fluid pressure is zero, (A) is an explanatory view of a cross section of the thin plate ring, and (B) is a surface pressure distribution diagram in which the inner peripheral edge of the thin plate ring contacts the outer peripheral surface of the pipe. FIG. 6A shows a state in which a medium level fluid pressure is applied, FIG. 7A is a sectional shape explanatory view of a thin plate ring, and FIG. FIG. 7A is a cross-sectional shape explanatory view of the thin plate ring, and FIG. 6B is a surface pressure distribution diagram in which the inner peripheral edge of the thin plate ring contacts the outer peripheral surface of the pipe. It is an expanded sectional view showing three examples of a thin plate ring. It is an expanded sectional view showing three examples of a rubber sealant. It is an expanded sectional explanatory view showing four examples of a shape of a chamfer. It is the figure which showed other embodiment of this invention, (A) is sectional drawing of the completion state of connection, (B) is a disassembled perspective view for description of main components. It is a simplified explanatory view of a dimensional relationship of main parts. FIG. 10 is a cross-sectional view of a semi-obtained main portion showing a conventional example. It is an expanded sectional view of a sealing material (O ring) for explaining the conventional problem.

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
In FIG. 1, in the pipe insertion hole 2A of the pipe joint body 2, a rubber sealing material such as an O-ring that is in close contact with the outer peripheral surface 3 of the pipe P ₀ and prevents the sealed fluid F from leaking to the outside. The pipe joint 1 provided with 10 is illustrated.

Further, the pipe joint body 2 has a fixed portion 4 having a flow hole portion and a nut-shaped short tubular body 5, and the short tubular body 5 is rotatable about the axis with respect to the fixed portion 4. They are connected via a retaining ring 6. Further, it has a cylindrical retainer 31 having a tapered male screw portion 31A, and when the retainer 31 is screwed forward, a continuous string 33 rotatably embedded in the retainer 31 spirals on the surface of the pipe P _0. The pipe P ₀ is configured to bite while forming a groove so that the pipe P ₀ does not pull out from the pipe joint body 2.
It should be noted that, in FIG. 1, when a short tubular body 5 having the same configuration is arranged at the other end (not shown) of the fixing portion 4, or a tapered male screw portion is integrally formed with the fixing portion. Or a short cylinder or the like having a different structure or shape is provided. Further, the fixed portion 4 may be curved as an elbow type or may be branched into a T shape (not shown).

A concave peripheral groove 8 having a rectangular cross section is formed in the pipe insertion hole 2A of the joint body 2, and the seal material 10 and the thin plate ring 20 are mounted in the concave peripheral groove 8.
Specifically, as shown in FIGS. 1 and 2, a first side surface 8A of the rectangular concave circumferential groove 8 closer to the inner side of the pipe joint body 2 (see the arrow N in FIG. 1) and the seal. A thin plate ring 20 is interposed between the material 10 and the material 10.

  FIG. 2 exemplifies a case where the concave circumferential groove 8 is simply provided in the joint main body 2 by cutting or the like, but in the embodiment of FIG. 1, a closed annular spacer 7 is added to form the concave circumferential groove. The case where the groove 8 is formed is shown as an example, and any one is free. In addition, in FIG. 1, a large diameter portion that opens outward (opposite the arrow N) is formed on one end surface of the fixed portion 4, and the large diameter portion is closed by the spacer 7. A circumferential groove 8 having a rectangular cross section is formed. Although illustrated in a simplified manner in FIG. 2, the second side surface 8B with which the sealing material 10 contacts corresponds to the one surface 7B of the spacer 7 in FIG.

In the pipe-uninserted state shown in FIG. 2, a thin plate ring 20 is arranged in a plane orthogonal to the axis L ₂ (see FIG. 1) of the hole 2A. In other words, the thin plate ring 20 has a closed annular ring shape which is arranged on the orthogonal plane orthogonal to the axis L ₂ of the hole 2A when the pipe is not inserted.
The material of the thin plate ring 20 is plastic, and for example, heat resistant polyethylene is suitable. The thin plate ring 20 (which is a ring having a closed annular shape as a whole) is arranged closer to the inner side N of the pipe joint body in which the sealed fluid F flows than the sealing material 10.

Then, in the free state shown in FIGS. 8A, 8B, and 8C, and in the pipe uninserted state shown in FIG. 2, the thin plate ring 20 has a cross-sectional shape of vertical single letter type, and The inner peripheral edge 21 is in the shape of a sword whose wall thickness decreases in the radial inward direction.
With such a simple shape, the thin plate ring 20 can be manufactured inexpensively and easily by injection molding, machining (from the plate material), or the like.

As shown in FIGS. 2 to 3, by inserting the pipe P ₀ (see arrow E), the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed in a J-shaped cross section toward the inner side N of the pipe joint body 2. To do. Then, in the connection completed state shown in FIGS. 4, 5, and 1, the inner peripheral edge 21 of the sealing material 10 elastically comes into close contact (pressure contact) with the outer peripheral surface 3 of the inserted pipe P ₀ .
In the subsequent use condition, the sealed fluid F such as hot water reaches the thin plate ring 20 deformed in the J-shaped cross section, and as shown in FIGS. 5, 6 and 7, the pressure P ranges from low pressure to high pressure. Even if it is pushed outward (to the right in the figure), regardless of the level of the pressure P, it is possible to cleverly perform the sealing action while always being in pressure contact with the outer peripheral surface of the pipe P ₀ .

  Although the rubber-degrading gas such as ozone (active oxygen), chlorine, and hydrogen is mixed (dissolved) in the sealed fluid F (hot water, etc.), as shown in FIG. 5, FIG. 6, and FIG. By the clever sealing function (function) of the thin plate ring 20, it is possible to reduce or block the contact of the rubber-degrading gas with the rubber seal material 10 (outside).

Then, as shown in FIGS. 2 to 7 and FIG. 10, at the corner portion 11 formed by the first side surface 8A of the concave circumferential groove 8 and the pipe insertion hole portion 2A, the inner peripheral edge 21 of the thin plate ring 20 is formed. Is formed with a chamfer C ₁₁ that allows the elastic deformation of the J-shaped section.
Moreover, the chamfer C ₁₁ also has a function of preventing the inner peripheral edge 21 of the thin plate ring 20 from being excessively elastically deformed.

That is, assuming a case where a notch having a sufficiently large rectangular cross section is formed in the corner portion 11 (not shown), it is assumed that the medium to high pressure P is as shown in FIG. 6 (or FIG. 7). At the moment when the pressure P suddenly drops from the actuated state, an excessive elastic deformation occurs inwardly N as compared with the J-shaped curved state shown in FIG. 5, and the innermost peripheral end 22 and the outer periphery of the pipe P ₀ . A minute gap may be generated between the surfaces 3, and the fluid F may pass through the gap and come into contact with the sealing material 10. That is, there is a possibility that a momentary passage of fluid may occur.

However, when the pressure further decreases from the low pressure state of FIGS. 4 and 5, as can be seen from the drawings of FIGS. 4 and 5, the inner peripheral edge 21 of the thin plate ring 20 is reliably chamfered to C ₁₁ . The chamfer C ₁₁ is small so that it can be abutted (supported).
That is, as shown in FIG. 10 (A) or (D), the inclination angle θ ₁ is set to be as small as 15 ° to 35 °. More preferably, the angle is 20 ° to 32 °. Further, as shown in FIG. 10 (D), it is also desirable to add a minimal radius portion R to the inner peripheral end corner portion of the inclination angle θ ₁ .

Further, as shown in FIG. 10 (B) and FIGS. 2 to 7, the main chamfer having an inclination angle θ ₁ of 15 ° to 35 ° (preferably 20 ° to 32 °) and the inner circumference thereof. It is also desirable to add a notch-formed sub chamfer C ₁₂ to the end corner portion with an inclination angle θ ₂ of 40 ° to 55 °.
Further, as shown in FIG. 10C, a round chamfered portion R ₀ having a slightly larger radius of curvature may be formed.

Next, further describing FIGS. 5, 6 and 7, each figure (B) shows the position in the axial direction on the horizontal axis, and the inner peripheral edge 21 is the outer peripheral surface 3 of the pipe P _{0 on} the vertical axis. is a graph showing the surface pressure P ₂₁ in contact with.
5A and 5B show the case where the fluid pressure is zero (or extremely small). As described above, the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed into a J-shaped cross section as the pipe P ₀ is inserted into the inner side N, so that the elastic biasing force of the ring 20 itself is exerted on the pipe outer peripheral surface 3. By acting, a low mountain-shaped surface pressure distribution curve appears.

FIG. 6A shows the case where the medium level fluid pressure P acts, and as shown in FIG. 6B, the surface pressure P ₂₁ becomes a medium level value. The J-shaped inner peripheral edge 21 slightly moves outward (where the sealing material 10 exists).
7 (A) and 7 (B) show a case where a high fluid pressure is applied. The thin plate ring 20 is elastically deformed outward, and the outer surface is supported by the sealing material 10, and the high surface pressure P _{21 is obtained} . Moreover, the pipe outer peripheral surface 3 is brought into a pressure contact state with a large contact area.

As described above, the higher the fluid pressure P is, the higher the surface pressure P _{21 is,} and the pressure is applied to the outer peripheral surface 3 of the pipe, so that the sealed fluid F is reliably blocked from contacting the sealing material 10, or (at least ) Can be reduced.
Further, even when the fluid pressure as shown in FIG. 5 (A) is zero, and even when the pressure is negative, the elastic force of the inner peripheral edge 21 (innermost peripheral edge 22) of the thin plate ring 20 elastically deformed into a J-shape. It can be surely shut off (reduced) by the urging force.

Further, in hot water supply pipes and the like, fluid pressure often fluctuates rapidly or pulsates due to opening and closing of a faucet, changes in flow rate, and the like.
However, as shown in FIG. 5, FIG. 6, and FIG. 7, the J-shaped inner peripheral edge 21 (innermost peripheral edge 22) is elastically deformed flexibly and promptly to surely exhibit the sealing performance (sealing performance). The rubber deterioration gas such as ozone (active oxygen), chlorine, hydrogen mixed in the sealed fluid (hot water, water, etc.) is significantly reduced from coming into contact with the rubber sealing material 10, Or to prevent chemical deterioration (corrosion) of the sealing material 10.

  FIG. 8 shows three embodiments of a thin plate ring 20 having an inner peripheral edge 21 having a sword-like cross section. 2A is an enlarged view of the thin plate ring 20 illustrated in FIGS. 2 to 7, and shows a case of a double-edged type. FIG. 8B is a single-edged type in which the sloped surface corresponds to the outside (atmosphere) side, and FIG. 8C shows the sloped surface corresponds to the inside (the side where the sealed fluid exists). It is a single-edged type. Either of FIGS. 8A, 8B, and 8C is adopted depending on the use condition, application, and the like.

  Next, FIG. 9 exemplifies a cross section of the sealing material 10. FIG. 9A shows an O-ring, FIG. 9B shows a U-shaped seal, and FIG. 9C shows a V-shape. The sealing material 10 of is shown. Note that the sealing material 10 having a rectangular cross section, a pentagon, or the like other than this can be freely used.

By the way, in the simplified explanatory view of FIG. 12, the dimensional relationship between the thin plate ring 20 and the concave circumferential groove 8 will be described below. The dimension (2 · ΔT) is smaller than the inner diameter of the groove bottom surface 8C of the concave circumferential groove 8. ), It is desirable to set the outer diameter of the thin plate ring 20 large.
That is, the thin plate ring 20 is attached to the groove bottom surface 8C by a small dimension ΔT on one side so as to be pressed in slightly, whereby the fluid can be prevented from entering the sealing material 10.

Further, as shown in FIG. 12, the (outer diameter side) starting point 13 of the first side surface 8A of the chamfer C ₁₁ and the starting point 24 of the inclined surface 23 at the inner peripheral edge 21 of the (free state) thin plate ring 20, It is desirable to set the radial dimension from the hole axis L ₂ to be substantially the same.
That is, in FIG. 12, the radii R ₁₃ and R ₂₄ of the point 13 and the point ₂₄ are made substantially equal. As a result, as shown in FIG. 3, FIG. 4, FIG. 5, etc., the inner peripheral edge 21 of the thin plate ring 20 is easily elastically deformed into a J-shape, and the outer peripheral surface 3 of the pipe P ₀ is appropriately elastically biased. Close to.

Next, FIG. 11 shows another embodiment of the present invention. 11 At a (A), the metal pipe P _0, and fitted with metal rings M of閉円cyclic, by applying an external force direction of reducing the diameter near the end of the pipe P _0, the pipe P ₀ The metal ring M is bited into the outer peripheral surface 3 of the and fixed. With the metal ring M fixed in this way, the locking projection 26 is formed.
A concave peripheral groove 8 into which a sealing material 10 such as a U packing shown in FIG. 9B is fitted is formed in the pipe insertion hole 2A of the pipe joint body 2. In FIG. 11, yet another concave circumferential groove 8'is formed at the outer position, and a sealing material 10 'such as an O-ring is fitted therein.
The sealing material 10 and the thin plate ring 20 are mounted in the former concave groove 8 having a rectangular cross section. The thin plate ring 20 is arranged closer to the pipe joint inner side N where the sealed fluid F flows than the sealing material 10 (as described above).

As already described with reference to FIGS. 2 and 3, when the pipe P ₀ is inserted in the direction of the arrow E, the inner peripheral edge of the thin plate ring 20 is elastically deformed toward the inner side N in a J-shaped cross section, and Elastically close to the outer peripheral surface 3 of P ₀ .
As shown in FIGS. 11 (A) and 11 (B), the joint main body 2 is provided with a pressure holding ring 14 that can be held by hand and attached in an externally fitted shape. The tip outer peripheral surface 2C of the joint body 2 and the inner peripheral surface 14A of the pressure holding ring 14 are engaged with each other by fitting the pressure holding ring 14 toward each other in the axial direction and by rotating at a small angle in the radial direction. The locking means 100 is provided.
By this locking means 100, the inner peripheral portion outer end region 14B of the pressure holding ring 14 and the inner peripheral portion front end region 2D of the joint main body 2 are axially outward with respect to the locking protruding portion 26. It is in a state of being held from inside (a state in which it cannot be pulled out).

Further, specifically explaining the locking means 100, as shown in FIGS. 11 (A) and (B), in the joint main body 2, a plurality of arc-shaped outer projecting ridges 15 and smooth arc-shaped portions are formed on the outer peripheral surface 2C of the tip thereof. The bottom surface portions 16 are alternately arranged, and each arc-shaped outer ridge portion 15 is composed of a pair of outer ridge portions 15A and 15B forming a locking groove portion 17 therebetween.
Further, in the pressure holding ring 14, the inner peripheral surface 14A thereof has an arcuate inner shape which is engageable with the locking groove portion 17 between the pair of outer projecting strips 15A and 15B by a small angle rotation in the radial direction. A plurality of ridges 18 are provided, and an arcuate slit portion 19 is axially provided between the adjacent inner ridges 18, 18 so that the locking means 100 has a locking groove 17 and The arc-shaped inner ridge portion 18 is provided.

In this way, the small number of manual rotations of 15 ° to 90 ° (for example) allow the pressing retaining ring 14 to grip the ridge 26, and the connection work can be performed easily and quickly.
The ridge 26 may be formed by locally plastically processing the pipe P ₀ .
In the embodiment of FIG. 11 as well, when the pipe P ₀ is inserted into the pipe joint body 2, the thin plate ring 20 having a cross-section orthogonal to the axial center elastically deforms in a J shape to protect the seal material 10. To do.
As long as the pipe P ₀ is inserted into the hole 2A of the pipe joint body 2 to prevent the pipe from coming off, the present invention can be freely applied to pipe joints having configurations other than those shown in FIGS. 1 and 11. It can be applied.

Further, although not shown, a concave groove (narrow width) different from the concave peripheral groove 8 in which only the sealing material 10 is mounted is provided in the hole portion 2A at a position closer to the inner side N than the concave peripheral groove 8. However, the thin plate ring 20 may be attached to the concave groove. At that time, it is desirable to provide a chamfer C ₁₁ on the inner side N side of the groove as in the above-described first side 8A.
Further, it is also free to install (laminate) the two thin plate rings 20, 20 in the concave circumferential groove 8 or the concave groove, and by mounting the two thin plates rings 20 in such a manner, it becomes possible to perform fluid operation by the labyrinth action. Can be reduced or the blocking action can be enhanced (not shown).

As described in detail above, the present invention provides a rubber sealing material that prevents the sealed fluid F from leaking to the pipe insertion hole 2A of the pipe joint body 2 by closely contacting the outer peripheral surface 3 of the pipe P _0. In a pipe joint provided with 10, a thin plate ring 20 is arranged in the hole 2A in a plane orthogonal to the axis L ₂ of the hole in a state where the pipe is not inserted. The thin plate ring 20 is disposed closer to the inner side N of the pipe joint main body through which the sealed fluid F flows, and the inner peripheral edge 21 of the thin plate ring 20 has a cross-section blade point whose thickness decreases in the radial inward direction. When the pipe P ₀ is inserted, the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed in a J-shaped cross section toward the inner side N of the pipe joint body 2, and in the connection completed state, the sealed fluid is sealed. When the rubber-deteriorating gas mixed in F comes into contact with the sealing material 10, the thin plate ring 20 Since it is configured so as to reduce or cut off, the elastic deformation of the thin plate ring 20 having a simple cross-sectional shape, which accompanies the pipe insertion, is skillfully used to achieve the intended purpose. It is possible to prevent a rubber-degrading gas such as chlorine gas from reaching the rubber sealing material 10. As a result, it is possible to prevent the rubber seal material 10 from being corroded (deteriorated) and generating the conventional defective portion G (as shown in FIG. 14).
That is, it is possible to reliably prevent the occurrence of an external leakage accident in the conventional hot water supply pipe or the like with a simple configuration.

Further, according to the present invention, the hole 2A of the pipe joint body 2 is provided with a concave circumferential groove 8 having a rectangular cross section for mounting the sealing material 10, and the concave circumferential groove 8 is provided inside the pipe joint body. Since the thin plate ring 20 is interposed between the first side surface 8A on the side and the sealing material 10, the J-shaped thin plate ring (as described with reference to FIGS. 5 to 7). The 20 is elastically deformable and can cope with a sudden pressure fluctuation (pulsation) from low pressure to high pressure.
Therefore, the J-shaped thin plate ring 20 cleverly copes with the pipe joint of the pipe near the faucet where the flow of the fluid F frequently changes, as described in FIGS. While maintaining the sealing performance.

In addition, at the corner portion 11 formed by the first side surface 8A of the concave circumferential groove 8 and the pipe insertion hole portion 2A, the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed into a J-shaped cross section. Since a chamfer C ₁₁ is formed to allow and prevent excessive elastic deformation, the thin plate ring 20 as a whole maintains a stable posture, and is properly inserted when the pipe is inserted and under a low pressure condition. The inner peripheral edge 21 is elastically deformed into a J-shape, and the pipe outer peripheral surface 3 is brought into close contact with the pipe outer peripheral surface 3 with a low surface pressure P ₂₁ (as shown in FIG. In addition, it is prevented that the inner peripheral edge 21 is damaged and the fluid F is momentarily passed (blow-by) due to excessive deformation to the inward N when the pressure fluctuation is severe or a negative pressure occurs. it can.

2 pipe joint body 2A hole 3 outer peripheral surface 8 concave peripheral groove 8A first side surface
10 Seal material
11 corners
20 thin plate ring
21 Inner peripheral edge F (Sealed) Fluid P ₀ Pipe N Inward L ₂ Shaft center C ₁₁ Chamfer

  The present invention relates to a pipe joint.

Conventionally, pipe joints having various configurations have been used for hot water supply pipes and the like.
For example, the conventional pipe joint shown in FIG. 13 has been proposed by the present applicants and is popular in the market (see Patent Document 1).
That is, when the cylindrical retainer 41 having the tapered male screw portion 41A is screwed in, the continuous beads 43 rotatably embedded in the retainer 41 bite into the surface of the pipe 45 while forming a spiral groove, The pipe 45 can be connected to the joint body 46 so as not to be pulled out.

The joint body 46 is composed of a fixed portion 48 having a through hole portion, and a short tubular body 44 rotatably connected to one end of the fixed portion 48 via a retaining ring 47. The short cylindrical body 44 is formed with a taper female screw portion 44A.
The pipe 45 is inserted into the hole of the joint body 46 (as shown in FIG. 13), but the O-ring (sealing material) 50 provided in the hole of the joint body 46 is attached to the outer peripheral surface of the pipe 45. It is a structure that closely prevents the leak of the sealed fluid such as hot water and water.

Japanese Patent No. 3568904

However, when the pipe joint described in Patent Document 1 (FIG. 13) is used as a pipe joint for hot water supply piping for several months to several years, the O-ring 50 has an outer surface (as shown in the enlarged view of FIG. 14). It was found that there is a possibility that a defective portion G may be generated and an external leakage accident may occur.
Therefore, an object of the present invention is to reliably prevent external leakage of such a pipe joint for hot water supply piping with a simple and inexpensive structure.
Furthermore, many pipe joints (including the above-mentioned Patent Document 1) according to the recent patented invention, which can significantly improve the work efficiency at the pipe connection work site, reduce reliability due to the occurrence of the above-mentioned external leakage accident, and are widely used. It is also an object to improve / solve the delay in using a simple and inexpensive configuration.

The pipe joint according to the present invention is a pipe joint in which a pipe sealing hole portion of a pipe joint body is provided with a rubber sealing material that is in close contact with an outer peripheral surface of the pipe and prevents external leakage of a sealed fluid. A thin plate ring is arranged in the hole in a plane orthogonal to the axis of the hole in a state where the pipe is not inserted, and moreover, in the inner side of the pipe joint body in which the sealed fluid flows rather than the sealing material. The thin plate ring is disposed, and the inner peripheral edge of the thin plate ring has a pointed cross-section with a wall thickness decreasing in the radial inward direction; The thin plate ring reduces or blocks contact of the rubber-deteriorating gas mixed in the sealed fluid with the sealing material when the connection is completed and elastically deforms inward in a J-shape. the hole of the pipe joint body; structure forms to Is provided with a concave circumferential groove having a rectangular cross section for mounting the sealing material, and the thin plate ring is provided between the sealing material and the first side surface of the concave circumferential groove, which is closer to the inner side of the pipe joint body. Intervening ; allowing the inner peripheral edge of the thin plate ring to elastically deform into a J-shaped cross section at the corner formed by the first side surface of the concave circumferential groove and the pipe insertion hole, and A chamfer is formed to prevent excessive elastic deformation ; the thin plate ring elastically deformed in the J-shaped cross section is pressed against the pipe outer peripheral surface with higher surface pressure as the fluid pressure becomes higher. It is composed.

According to the present invention, with a thin plate ring having a simple cross-sectional shape, it is possible to reduce or block contact of a small amount of rubber-deteriorating gas in a sealed fluid with a rubber-made sealing material, thereby chemically degrading the sealing material ( Corrosion) can be prevented and external leakage of the sealed fluid (for a long period of time) can be prevented.
Moreover, the thin plate ring having a simple cross-sectional shape can be easily and inexpensively manufactured by injection molding or machining. In addition, in order for such a thin plate ring having such a simple shape to be deformed into a J-shaped cross section that most effectively seals the sealed fluid, a pipe may simply be inserted.

FIG. 3 is a cross-sectional view of a semi-main part in a connection completed state showing an embodiment of the present invention. It is a principal part expanded sectional view which shows a pipe uninserted state. It is a principal part expanded sectional view which shows the pipe intermediate state. It is a principal part expanded sectional view which showed the state of the completion of connection and the state before pressure reception. A fluid pressure is zero, (A) is an explanatory view of a cross section of the thin plate ring, and (B) is a surface pressure distribution diagram in which the inner peripheral edge of the thin plate ring contacts the outer peripheral surface of the pipe. FIG. 6A shows a state in which a medium level fluid pressure is applied, FIG. 7A is a sectional shape explanatory view of a thin plate ring, and FIG. FIG. 7A is a cross-sectional shape explanatory view of the thin plate ring, and FIG. 6B is a surface pressure distribution diagram in which the inner peripheral edge of the thin plate ring contacts the outer peripheral surface of the pipe. It is an expanded sectional view showing three examples of a thin plate ring. It is an expanded sectional view showing three examples of a rubber sealant. It is an expanded sectional explanatory view showing four examples of a shape of a chamfer. It is the figure which showed other embodiment of this invention, (A) is sectional drawing of the completion state of connection, (B) is a disassembled perspective view for description of main components. It is a simplified explanatory view of a dimensional relationship of main parts. FIG. 11 is a cross-sectional view of a semi-main part showing a conventional example. It is an expanded sectional view of a sealing material (O ring) for explaining the conventional problem.

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
In FIG. 1, in the pipe insertion hole 2A of the pipe joint body 2, a rubber sealing material such as an O-ring that is in close contact with the outer peripheral surface 3 of the pipe P ₀ and prevents the sealed fluid F from leaking to the outside. The pipe joint 1 provided with 10 is illustrated.

Further, the pipe joint body 2 has a fixed portion 4 having a flow hole portion and a nut-shaped short tubular body 5, and the short tubular body 5 is rotatable about the axis with respect to the fixed portion 4. They are connected via a retaining ring 6. Further, it has a cylindrical retainer 31 having a tapered male screw portion 31A, and when the retainer 31 is screwed forward, a continuous string 33 rotatably embedded in the retainer 31 spirals on the surface of the pipe P _0. The pipe P ₀ is configured to bite while forming a groove so that the pipe P ₀ does not pull out from the pipe joint body 2.
It should be noted that, in FIG. 1, when a short tubular body 5 having the same configuration is arranged at the other end (not shown) of the fixing portion 4, or a tapered male screw portion is integrally formed with the fixing portion. Or a short cylinder or the like having a different structure or shape is provided. Further, the fixed portion 4 may be curved as an elbow type or may be branched into a T shape (not shown).

A concave peripheral groove 8 having a rectangular cross section is formed in the pipe insertion hole 2A of the joint body 2, and the seal material 10 and the thin plate ring 20 are mounted in the concave peripheral groove 8.
Specifically, as shown in FIGS. 1 and 2, a first side surface 8A of the rectangular concave circumferential groove 8 closer to the inner side of the pipe joint body 2 (see the arrow N in FIG. 1) and the seal. A thin plate ring 20 is interposed between the material 10 and the material 10.

  FIG. 2 exemplifies a case where the concave circumferential groove 8 is simply provided in the joint main body 2 by cutting or the like, but in the embodiment of FIG. 1, a closed annular spacer 7 is added to form the concave circumferential groove. The case where the groove 8 is formed is shown as an example, and any one is free. In addition, in FIG. 1, a large diameter portion that opens outward (opposite the arrow N) is formed on one end surface of the fixed portion 4, and the large diameter portion is closed by the spacer 7. A circumferential groove 8 having a rectangular cross section is formed. Although illustrated in a simplified manner in FIG. 2, the second side surface 8B with which the sealing material 10 contacts corresponds to the one surface 7B of the spacer 7 in FIG.

In the pipe-uninserted state shown in FIG. 2, a thin plate ring 20 is arranged in a plane orthogonal to the axis L ₂ (see FIG. 1) of the hole 2A. In other words, the thin plate ring 20 has a closed annular ring shape which is arranged on the orthogonal plane orthogonal to the axis L ₂ of the hole 2A when the pipe is not inserted.
The material of the thin plate ring 20 is plastic, and for example, heat resistant polyethylene is suitable. The thin plate ring 20 (which is a ring having a closed annular shape as a whole) is arranged closer to the inner side N of the pipe joint body in which the sealed fluid F flows than the sealing material 10.

Then, in the free state shown in FIGS. 8A, 8B, and 8C, and in the pipe uninserted state shown in FIG. 2, the thin plate ring 20 has a cross-sectional shape of vertical single letter type, and The inner peripheral edge 21 is in the shape of a sword whose wall thickness decreases in the radial inward direction.
With such a simple shape, the thin plate ring 20 can be manufactured inexpensively and easily by injection molding, machining (from the plate material), or the like.

As shown in FIGS. 2 to 3, by inserting the pipe P ₀ (see arrow E), the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed in a J-shaped cross section toward the inner side N of the pipe joint body 2. To do. Then, in the connection completed state shown in FIGS. 4, 5, and 1, the inner peripheral edge 21 of the sealing material 10 elastically comes into close contact (pressure contact) with the outer peripheral surface 3 of the inserted pipe P ₀ .
In the subsequent use condition, the sealed fluid F such as hot water reaches the thin plate ring 20 deformed in the J-shaped cross section, and as shown in FIGS. 5, 6 and 7, the pressure P ranges from low pressure to high pressure. Even if it is pushed outward (to the right in the figure), regardless of the level of the pressure P, it is possible to cleverly perform the sealing action while always being in pressure contact with the outer peripheral surface of the pipe P ₀ .

  Although the rubber-degrading gas such as ozone (active oxygen), chlorine, and hydrogen is mixed (dissolved) in the sealed fluid F (hot water, etc.), as shown in FIG. 5, FIG. 6, and FIG. By the clever sealing function (function) of the thin plate ring 20, it is possible to reduce or block the contact of the rubber-degrading gas with the rubber sealing material 10 (disposed on the outer side).

Then, as shown in FIGS. 2 to 7 and FIG. 10, at the corner portion 11 formed by the first side surface 8A of the concave circumferential groove 8 and the pipe insertion hole portion 2A, the inner peripheral edge 21 of the thin plate ring 20 is formed. Is formed with a chamfer C ₁₁ that allows the elastic deformation of the J-shaped section.
Moreover, the chamfer C ₁₁ also has a function of preventing the inner peripheral edge 21 of the thin plate ring 20 from being excessively elastically deformed.

That is, assuming a case where a notch having a sufficiently large rectangular cross section is formed in the corner portion 11 (not shown), it is assumed that the medium to high pressure P is as shown in FIG. 6 (or FIG. 7). At the moment when the pressure P suddenly drops from the actuated state, an excessive elastic deformation occurs inwardly N as compared with the J-shaped curved state shown in FIG. 5, and the innermost peripheral end 22 and the outer periphery of the pipe P ₀ . A minute gap may be generated between the surfaces 3, and the fluid F may pass through the gap and come into contact with the sealing material 10. That is, there is a possibility that a momentary passage of fluid may occur.

However, when the pressure further decreases from the low pressure state of FIGS. 4 and 5, as can be seen from the drawings of FIGS. 4 and 5, the inner peripheral edge 21 of the thin plate ring 20 is reliably chamfered to C ₁₁ . The chamfer C ₁₁ is small so that it can be abutted (supported).
That is, as shown in FIG. 10 (A) or (D), the inclination angle θ ₁ is set to be as small as 15 ° to 35 °. More preferably, the angle is 20 ° to 32 °. Further, as shown in FIG. 10 (D), it is also desirable to add a minimal radius portion R to the inner peripheral end corner portion of the inclination angle θ ₁ .

Further, as shown in FIG. 10 (B) and FIGS. 2 to 7, the main chamfer having an inclination angle θ ₁ of 15 ° to 35 ° (preferably 20 ° to 32 °) and the inner circumference thereof. It is also desirable to add a notch-formed sub chamfer C ₁₂ to the end corner portion with an inclination angle θ ₂ of 40 ° to 55 °.
Further, as shown in FIG. 10C, a round chamfered portion R ₀ having a slightly larger radius of curvature may be formed.

Next, further describing FIGS. 5, 6 and 7, each figure (B) shows the position in the axial direction on the horizontal axis, and the inner peripheral edge 21 is the outer peripheral surface 3 of the pipe P _{0 on} the vertical axis. is a graph showing the surface pressure P ₂₁ in contact with.
5A and 5B show the case where the fluid pressure is zero (or extremely small). As described above, the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed into a J-shaped cross section as the pipe P ₀ is inserted into the inner side N, so that the elastic biasing force of the ring 20 itself is exerted on the pipe outer peripheral surface 3. By acting, a low mountain-shaped surface pressure distribution curve appears.

FIG. 6A shows the case where the medium level fluid pressure P acts, and as shown in FIG. 6B, the surface pressure P ₂₁ becomes a medium level value. The J-shaped inner peripheral edge 21 slightly moves outward (where the sealing material 10 exists).
7 (A) and 7 (B) show a case where a high fluid pressure is applied. The thin plate ring 20 is elastically deformed outward, and the outer surface is supported by the sealing material 10, and the high surface pressure P _{21 is obtained} . Moreover, the pipe outer peripheral surface 3 is brought into a pressure contact state with a large contact area.

As described above, the higher the fluid pressure P is, the higher the surface pressure P _{21 is,} and the pressure is applied to the outer peripheral surface 3 of the pipe, so that the sealed fluid F is reliably blocked from contacting the sealing material 10, or (at least ) Can be reduced.
Further, even when the fluid pressure as shown in FIG. 5 (A) is zero and further negative pressure, the inner peripheral edge 21 (innermost peripheral edge 22) itself of the thin plate ring 20 elastically deformed into a J-shape. It can be surely shut off (reduced) by the elastic force.

Further, in hot water supply pipes and the like, fluid pressure often fluctuates rapidly or pulsates due to opening and closing of a faucet, changes in flow rate, and the like.
However, as shown in FIG. 5, FIG. 6, and FIG. 7, the J-shaped inner peripheral edge 21 (innermost peripheral edge 22) is elastically deformed flexibly and promptly to surely exhibit the sealing performance (sealing performance). , Remarkably reduces or blocks contact of rubber- degrading gas such as ozone (active oxygen), chlorine, hydrogen mixed in the sealed fluid (hot water, water, etc.) with the rubber sealing material 10. Then, the chemical deterioration (corrosion) of the sealing material 10 is prevented.

  FIG. 8 shows three embodiments of a thin plate ring 20 having an inner peripheral edge 21 having a sword-like cross section. 2A is an enlarged view of the thin plate ring 20 illustrated in FIGS. 2 to 7, and shows a case of a double-edged type. FIG. 8B is a single-edged type in which the sloped surface corresponds to the outside (atmosphere) side, and in FIG. 8C, the sloped surface corresponds to the inside (the side where the sealed fluid exists). It is a single-edged type. One of FIGS. 8A, 8B, and 8C is adopted depending on the use condition, application, and the like.

  Next, FIG. 9 exemplifies a cross section of the sealing material 10. FIG. 9A shows an O-ring, FIG. 9B shows a U-shaped seal, and FIG. 9C shows a V-shape. The sealing material 10 of is shown. Note that the sealing material 10 having a rectangular cross section, a pentagon, or the like other than this can be freely used.

By the way, in the simplified explanatory view of FIG. 12, the dimensional relationship between the thin plate ring 20 and the concave circumferential groove 8 will be described below. The dimension (2 · ΔT) is smaller than the inner diameter of the groove bottom surface 8C of the concave circumferential groove 8. ), It is desirable to set the outer diameter of the thin plate ring 20 large.
That is, the thin plate ring 20 is attached to the groove bottom surface 8C by a small dimension ΔT on one side so as to be pressed in slightly, whereby the fluid can be prevented from entering the sealing material 10.

Further, as shown in FIG. 12, the (outer diameter side) starting point 13 of the first side surface 8A of the chamfer C ₁₁ and the starting point 24 of the inclined surface 23 at the inner peripheral edge 21 of the (free state) thin plate ring 20, It is desirable to set the radial dimension from the hole axis L ₂ to be substantially the same.
That is, in FIG. 12, the radii R ₁₃ and R ₂₄ of the point 13 and the point ₂₄ are made substantially equal. As a result, as shown in FIG. 3, FIG. 4, FIG. 5, etc., the inner peripheral edge 21 of the thin plate ring 20 is easily elastically deformed into a J-shape, and the outer peripheral surface 3 of the pipe P ₀ is appropriately elastically biased. Close to.

Next, FIG. 11 shows another embodiment of the present invention. 11 At a (A), the metal pipe P _0, and fitted with metal rings M of閉円cyclic, by applying an external force direction of reducing the diameter near the end of the pipe P _0, the pipe P ₀ The metal ring M is bited into the outer peripheral surface 3 of the and fixed. With the metal ring M fixed in this way, the locking projection 26 is formed.
A concave peripheral groove 8 into which a sealing material 10 such as a U packing shown in FIG. 9B is fitted is formed in the pipe insertion hole 2A of the pipe joint body 2. In FIG. 11, yet another concave circumferential groove 8'is formed at the outer position, and a sealing material 10 'such as an O-ring is fitted therein.
The sealing material 10 and the thin plate ring 20 are mounted in the former concave groove 8 having a rectangular cross section. The thin plate ring 20 is arranged closer to the pipe joint inner side N where the sealed fluid F flows than the sealing material 10 (as described above).

As already described with reference to FIGS. 2 and 3, when the pipe P ₀ is inserted in the direction of the arrow E, the inner peripheral edge of the thin plate ring 20 is elastically deformed toward the inner side N in a J-shaped cross section, and Elastically close to the outer peripheral surface 3 of P ₀ .
As shown in FIGS. 11 (A) and 11 (B), the joint main body 2 is provided with a pressure holding ring 14 that can be held by hand and attached in an externally fitted shape. The tip outer peripheral surface 2C of the joint body 2 and the inner peripheral surface 14A of the pressure holding ring 14 are engaged with each other by fitting the pressure holding ring 14 toward each other in the axial direction and by rotating at a small angle in the radial direction. The locking means 100 is provided.
By this locking means 100, the inner peripheral portion outer end region 14B of the pressure holding ring 14 and the inner peripheral portion front end region 2D of the joint main body 2 are axially outward with respect to the locking protruding portion 26. It is in a state of being held from inside (a state in which it cannot be pulled out).

Further, specifically explaining the locking means 100, as shown in FIGS. 11 (A) and (B), in the joint main body 2, a plurality of arc-shaped outer projecting ridges 15 and smooth arc-shaped portions are formed on the outer peripheral surface 2C of the tip thereof. The bottom surface portions 16 are alternately arranged, and each arc-shaped outer ridge portion 15 is composed of a pair of outer ridge portions 15A and 15B forming a locking groove portion 17 therebetween.
Further, in the pressure holding ring 14, the inner peripheral surface 14A thereof has an arcuate inner shape which is engageable with the locking groove portion 17 between the pair of outer projecting strips 15A and 15B by a small angle rotation in the radial direction. A plurality of ridges 18 are provided, and an arcuate slit portion 19 is axially provided between the adjacent inner ridges 18, 18 so that the locking means 100 has a locking groove 17 and The arc-shaped inner ridge portion 18 is provided.

In this way, the small number of manual rotations of 15 ° to 90 ° (for example) allow the pressing retaining ring 14 to grip the ridge 26, and the connection work can be performed easily and quickly.
The ridge 26 may be formed by locally plastically processing the pipe P ₀ .
In the embodiment of FIG. 11 as well, when the pipe P ₀ is inserted into the pipe joint body 2, the thin plate ring 20 having a cross-section orthogonal to the axial center elastically deforms in a J shape to protect the seal material 10. To do.
As long as the pipe P ₀ is inserted into the hole 2A of the pipe joint body 2 to prevent the pipe from coming off, the present invention can be freely applied to pipe joints having configurations other than those shown in FIGS. 1 and 11. It can be applied.

Further, although not shown, a concave groove (narrow width) different from the concave peripheral groove 8 in which only the sealing material 10 is mounted is provided in the hole portion 2A at a position closer to the inner side N than the concave peripheral groove 8. However, the thin plate ring 20 may be attached to the concave groove. At that time, it is desirable to provide a chamfer C ₁₁ on the inner side N side of the groove as in the above-described first side 8A.
Further, it is also free to install (laminate) the two thin plate rings 20, 20 in the concave circumferential groove 8 or the concave groove, and by mounting the two thin plates rings 20 in such a manner, it becomes possible to perform fluid operation by the labyrinth action. Can be reduced or the blocking action can be enhanced (not shown).

As described in detail above, the present invention provides a rubber sealing material that prevents the sealed fluid F from leaking to the pipe insertion hole 2A of the pipe joint body 2 by closely contacting the outer peripheral surface 3 of the pipe P _0. In a pipe joint provided with 10, a thin plate ring 20 is arranged in the hole 2A in a plane orthogonal to the axis L ₂ of the hole in a state where the pipe is not inserted. The thin plate ring 20 is disposed closer to the inner side N of the pipe joint main body through which the sealed fluid F flows, and the inner peripheral edge 21 of the thin plate ring 20 has a cross-section blade point whose thickness decreases in the radial inward direction. When the pipe P ₀ is inserted, the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed in a J-shaped cross section toward the inner side N of the pipe joint body 2, and in the connection completed state, the sealed fluid is sealed. When the rubber-deteriorating gas mixed in F comes into contact with the sealing material 10, the thin plate ring 20 Since it is configured so as to reduce or cut off, the elastic deformation of the thin plate ring 20 having a simple cross-sectional shape, which accompanies the pipe insertion, is skillfully used to achieve the intended purpose. It is possible to prevent a rubber-degrading gas such as chlorine gas from reaching the rubber sealing material 10. As a result, it is possible to prevent the rubber seal material 10 from being corroded (deteriorated) and generating the conventional defective portion G (as shown in FIG. 14).
That is, it is possible to reliably prevent the occurrence of an external leakage accident in the conventional hot water supply pipe or the like with a simple configuration.

Further, according to the present invention, the hole 2A of the pipe joint body 2 is provided with a concave circumferential groove 8 having a rectangular cross section for mounting the sealing material 10, and the concave circumferential groove 8 is provided inside the pipe joint body. Since the thin plate ring 20 is interposed between the first side surface 8A on the side and the sealing material 10, the J-shaped thin plate ring (as described with reference to FIGS. 5 to 7). The 20 is elastically deformable and can cope with a sudden pressure fluctuation (pulsation) from low pressure to high pressure.
Therefore, the J-shaped thin plate ring 20 cleverly copes with the pipe joint of the pipe near the faucet where the flow of the fluid F frequently changes, as described in FIGS. While maintaining the sealing performance.

In addition, at the corner portion 11 formed by the first side surface 8A of the concave circumferential groove 8 and the pipe insertion hole portion 2A, the inner peripheral edge 21 of the thin plate ring 20 is elastically deformed into a J-shaped cross section. Since a chamfer C ₁₁ is formed to allow and prevent excessive elastic deformation, the thin plate ring 20 as a whole maintains a stable posture, and is properly inserted when the pipe is inserted and under a low pressure condition. The inner peripheral edge 21 is elastically deformed into a J-shape, and the pipe outer peripheral surface 3 is brought into close contact with the pipe outer peripheral surface 3 with a low surface pressure P ₂₁ (as shown in FIG. In addition, it is prevented that the inner peripheral edge 21 is damaged and the fluid F is momentarily passed (blow-by) due to excessive deformation to the inward N when the pressure fluctuation is severe or a negative pressure occurs. it can.

2 pipe joint body 2A hole 3 outer peripheral surface 8 concave peripheral groove 8A first side surface
10 Seal material
11 corners
13 Starting point on outer diameter side
20 thin plate ring
21 Inner edge
23 Inclined surface
24 Starting point F (sealed) fluid
P (Fluid) pressure P ₀ Pipe N Inward L ₂ Shaft center C ₁₁ Chamfer

Claims (3)

In the pipe insertion hole portion (2A) of the pipe joint body (2), a rubber sealing material that is in close contact with the outer peripheral surface (3) of the pipe (P ₀ ) and prevents external leakage of the sealed fluid (F) ( In the pipe fitting provided with 10),
In the state where the pipe is not inserted, the thin plate ring (20) is arranged in the hole (2A) as a plane orthogonal to the hole axis (L ₂ ), and moreover than the sealing material (10), the cover member The thin plate ring (20) is arranged near the inner side (N) of the pipe joint body in which the sealing fluid (F) flows, and the inner peripheral edge (21) of the thin plate ring (20) is radially inward. It has a cross-section sword-like shape with reduced thickness.
By inserting the pipe (P ₀ ), the inner peripheral edge (21) of the thin plate ring (20) is elastically deformed in a J-shaped cross section toward the inner side (N) of the pipe joint body (2),
The thin plate ring (20) is used to reduce or block the contact of the rubber-deteriorating gas mixed in the sealed fluid (F) with the sealing material (10) when the connection is completed. A pipe joint characterized by the following.   The hole (2A) of the pipe joint body (2) is provided with a concave circumferential groove (8) having a rectangular cross section for mounting the sealing material (10), and the pipe of the concave circumferential groove (8). The pipe joint according to claim 1, wherein the thin plate ring (20) is interposed between the first side surface (8A) near the inner side of the joint body and the sealing material (10). At the corner (11) formed by the first side surface (8A) of the concave circumferential groove (8) and the pipe insertion hole (2A), the inner peripheral edge (21) of the thin plate ring (20) is The pipe joint according to claim 2, wherein a chamfer (C ₁₁ ) is formed to allow elastic deformation in a J-shaped cross section and prevent excessive elastic deformation.

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