JP2012036984A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint which can detect the sticking out of a sealing ring from a holding groove due to insertion of a piping, and can solve the possibility of causing water leakage after a long period of time.SOLUTION: In a pipe joint 10, in a back side position of an O ring 24-2 of the insertion direction of a piping 20, a groove 70 of the shape of endless circularity along the outer periphery of an inner cylinder 18 for detecting the sticking out of the O ring 24-2 is provided in a position overlapping the position of sticking out portion, when a part of the circumferential direction of the O ring 24-2 held in the a holding groove 22-2 is pushed by the piping 20, and sticks out in an axial direction.

Description

  The present invention relates to a pipe joint, and more particularly, to a pipe joint of a type in which a space between a pipe and an inner cylinder part is sealed with a seal ring made of an elastic body held on an outer peripheral surface of an inner cylinder part.

  Conventionally, the joint body is provided with an inner cylinder part that fits the pipe in the axial direction by fitting the pipe in the axial direction, and the elasticity is held in the endless annular holding groove on the outer peripheral surface of the inner cylinder part. 2. Description of the Related Art Pipe joints that are watertightly sealed between an inner peripheral surface of a pipe and an outer peripheral surface of an inner cylinder portion are widely used in a seal ring made of a body.

In this pipe joint, the seal ring is usually protruded by a predetermined dimension radially outward from the outer peripheral surface of the inner cylinder part before the pipe is inserted, and when the pipe is inserted into the inner cylinder part (just insert) In this case, the seal ring is compressed radially with the inner peripheral surface of the pipe and the outer peripheral surface of the inner cylinder portion, more specifically the groove bottom surface of the holding groove, to seal between the pipe and the inner cylinder portion. In this case, when the pipe is inserted, a force from the pipe is received, and a part of the seal ring in the circumferential direction may come off the holding groove and may be lifted.
This is especially likely when the pipe is a resin pipe.

In recent years, for example, resin pipes made of a hard resin material such as polybutene and cross-linked polyethylene have been used as pipes for water supply and hot water supply.
In this case, it is possible to cut and connect a long pipe according to the situation at the construction site, to configure the pipe with an appropriate length according to the situation at the construction site, and to make a pipe connection in a good state. it can.

  However, in this case, in detail, when the pipe is cut, it may be cut obliquely. In this case, when the pipe is cut from the side cut obliquely in the axial direction with respect to the inner cylindrical portion, A part of the circumferential direction of the seal ring previously attached to the cylindrical portion may float from the holding groove.

FIG. 8 explains this in detail.
In FIG. 8, reference numeral 200 denotes an inner cylinder portion, and 202 denotes an endless annular groove formed on the outer peripheral surface and opened on the outer peripheral side, into which an elastic seal ring (here, O-ring) 204 is fitted. Is retained.
206 is a resin pipe, and 208 is a front end surface cut obliquely.

As shown in FIG. 8, when this pipe 206 is externally inserted from the front end surface 208 side to the inner tube portion 200 in the axial direction, the seal ring 204 is obliquely cut from the lower end in the drawing. The upper part in the drawing may be lifted from the holding groove 202 by being drawn up upward.
More specifically, when the pipe 206 is extrapolated in the axial direction to the inner cylinder portion 200 and the lower end portion in the drawing is fitted to the lower portion of the seal ring 204, the lower portion of the seal ring 204 is forcibly elastically deformed in the reduced diameter direction.
On the other hand, since the upper portion of the seal ring 204 is not yet restrained by the pipe 206, the seal ring 204 that is forcibly elastically deformed in the reduced diameter direction at the lower portion is made to squeeze up as if from the lower side to the upper side. Then, the upper part floats (protrudes) from the holding groove 202 (see FIG. 8I).

  In this state, when the pipe 206 is further pushed rightward in the figure, the upper part of the seal ring 204 that floats upward hits the front end surface 208 of the pipe 206 and is pushed rightward in the figure. As shown in B), it protrudes from the holding groove 202 to the right side in the figure (see FIG. 8 (II)).

A piping joint aimed at solving such a problem is disclosed in Patent Document 1 below.
The one disclosed in Patent Document 1 is provided with a coil spring (an anti-lifting spring) in a joint body and prevents the seal ring from rising by the action of the coil spring. An example is shown.

In FIG. 9, reference numeral 210 denotes a coil spring (lifting prevention spring). In the structure shown in FIG. 9, when the pipe 206 is inserted into the inner cylinder portion 200, the tip of the coil spring 210 becomes the tip surface of the pipe 206. When the seal ring 204 tries to lift from the holding groove 202 when the left side in the drawing covers the seal ring 204 from the outer peripheral side in a state where it is in contact with 208, the coil spring 210 is radially inward of the seal ring 204. The seal ring 204 works to prevent the seal ring 204 from rising.
Therefore, in the case of the pipe joint shown in FIG. 9, in a normal case, the seal ring 204 does not rise from the holding groove 202 when the pipe 206 is inserted.

  However, when the pipe 206 is inserted into the inner cylinder portion 200 in the field work, foreign matter 212 such as sand, wood pieces, and dust is sandwiched between the distal end surface 208 of the pipe 206 and the coil spring 210 as shown in FIG. In this case, the coil spring 210 cannot sufficiently exhibit the function of preventing the seal ring 204 from rising, and a part of the seal ring 204 in the circumferential direction is thereby held in the holding groove 202. May cause buoyancy.

  Thus, when a part of the seal ring 204 in the circumferential direction is lifted, the lifted part is pushed in the insertion direction as the pipe 206 is further inserted, as shown in FIG. As shown in the comparative example diagram, a part thereof protrudes from the holding groove 202 to the right along the outer peripheral surface of the inner cylinder 200 in the axial direction along the outer circumferential surface (72A in the figure indicates the protruding portion). It can happen that the pipe 206 is bitten.

  In such a state, normally, the seal ring 204 does not sufficiently perform a sealing action. Therefore, if water is passed in this state, water leakage usually occurs. Therefore, if a water flow inspection is performed after construction on site, it can be known that the seal ring 204 is not functioning sufficiently due to water leakage.

However, in rare cases, the seal ring 204 that protrudes in this manner may maintain a close contact state with the outer peripheral surface of the inner cylinder part 200 and the inner peripheral surface of the pipe 206 and may perform the sealing function as it is. .
In this case, since the seal ring 204 is not noticed to be in an abnormal state, if it is left as it is, for example, after a long period of time such as half a year or one year later, the seal ring 204 is caused by the occurrence of water hammer or other causes. It is feared that the sealing function due to will suddenly be lost, causing water leakage.
In this case, since it is difficult to notice that a water leak has occurred, this may lead to a large amount of water leak.

  The above problem due to the floating of the seal ring may occur not only when the pipe is a resin pipe, but also when the pipe is made of other materials, and the above coil spring (lifting prevention spring). This is a problem that may occur even in a device that does not have.

  As a prior art to the present invention, the following Patent Document 2 discloses a pipe joint provided with a means for detecting a seal failure due to a seal ring. It does not detect the protrusion from the holding groove, and is different from the present invention.

JP 2006-162060 A JP 2002-243087 A

  The present invention is based on the circumstances as described above, and it is possible to detect when the seal ring protrudes from the holding groove due to the insertion of the pipe, and a pipe joint that does not cause a problem of causing water leakage for the first time after a long period of time. It was made for the purpose of providing.

  Thus, according to the first aspect of the present invention, the joint body is provided with an inner cylindrical portion that is fitted in an internally fitted state with respect to the pipe by inserting the pipe in the axial direction. A seal ring made of an elastic body is held in a holding groove having an endless annular shape along the outer peripheral surface, and the seal is formed between the inner peripheral surface of the pipe and the outer peripheral surface of the inner cylindrical portion. In a pipe joint that is sealed in a water-tight manner with a ring, a position in the rear side of the holding groove in the insertion direction of the pipe, and a part of the circumferential direction of the seal ring held in the holding groove is An endless annular shape is formed along the outer peripheral surface of the inner cylindrical portion at a position adjacent to the protruding portion when it is detached from the holding groove and protrudes in the insertion direction along the outer peripheral surface of the inner cylindrical portion, and the seal A groove substantially parallel to the ring is provided.

  According to a second aspect of the present invention, in the first aspect, the groove is provided at a position close to the holding groove with a distance smaller than the width of the seal ring from the holding groove.

  According to a third aspect of the present invention, in any one of the first and second aspects, the groove has a groove width narrower than a width of the seal ring.

  According to a fourth aspect of the present invention, in the third aspect, the groove is a groove having a V-shaped cross section.

  According to a fifth aspect of the present invention, in the third aspect of the present invention, the groove is provided with a quadrangular cross section, and a corner portion on the opening side is chamfered.

Effects and effects of the invention

As described above, the present invention forms an endless ring along the outer peripheral surface of the inner cylinder portion at a position behind the holding groove in the pipe insertion direction and close to the holding groove, and is substantially parallel to the seal ring. According to the present invention, a portion of the seal ring in the circumferential direction is lifted when the pipe is inserted into the inner cylinder, and is further pushed in the axial direction by the insertion of the pipe. When protruding from the holding groove with elastic elongation deformation in the axial direction, the protruding portion overlaps the groove in the radial direction, thereby creating a gap due to the groove between the protruding portion and the outer peripheral surface of the inner cylindrical portion. Water leakage can be reliably caused when a water flow inspection is performed in this state.
Here, the groove is arranged at a position close to the holding groove that can be reached in the axial direction when a part of the seal ring in the circumferential direction is elastically deformed in the axial direction.

  Therefore, in spite of the fact that the seal ring protrudes from the holding groove, the seal function is rarely exhibited, and after a long period of use, the seal performance is lost for some reason, causing water leakage there. It is possible to prevent problems such as spilling, and to detect the protrusion of the seal ring at an early stage, and to reliably prevent a problem that leads to a large amount of water leakage due to water leakage after a long period of time.

  In the present invention, the groove is provided in an endless annular shape substantially parallel to the seal ring along the outer peripheral surface of the inner cylinder portion at a position close to the holding groove, that is, provided in a continuous annular shape over the entire circumference. When any part of the seal ring in the circumferential direction protrudes, it can be surely overlapped with the groove to detect the protrusion of the seal ring.

Here, the groove is preferably provided at a position close to the holding groove at a distance smaller than the width of the seal ring from the holding groove.
By arranging the groove in a position close to the holding groove in this way, when a part of the seal ring in the circumferential direction protrudes, it overlaps the groove in the radial direction, and the protruding part and the inner cylinder part A gap can be formed between the outer peripheral surface and the outer peripheral surface.

Further, it is desirable that the groove has a narrower groove width than the width of the seal ring.
If the groove width of the groove is larger than the width of the seal ring, the protruding part from the holding groove of the seal ring may fit into the groove and stick to the inner surface of the groove, or the gap However, according to the third aspect of the present invention, it is possible to prevent the protruding portion of the seal ring from fitting into the groove, and the protruding portion of the seal ring and the inner cylindrical portion of the groove portion can be prevented. A gap can be reliably formed between the outer peripheral surface and the outer peripheral surface.

In this case, the groove can be a groove having a V-shaped cross section.
By doing in this way, it can prevent more reliably that the protrusion part of a seal ring fits in the inside of a groove | channel, and the protrusion part fills the inside of a groove | channel and seals.

It is desirable that the corner portion on the opening side of the groove has a chamfered shape.
If the corner (edge) on the opening side has an edge shape, the protruding portion of the seal ring may be damaged at the edge.

If you notice that there is a water leak and remove the pipe and then connect it to the pipe joint again using the same seal ring, the damaged O-ring will continue to be used. Sealing may not be sufficient, and water leakage may occur.
In this sense, it is desirable that the corner portion on the opening side of the groove has a chamfered shape.

  However, when the groove is a groove having a V-shaped cross section, the tip of the tool for machining and forming the groove becomes narrow. In this case, if the corner is chamfered at the same time as the groove is formed, the tool becomes stronger. It is difficult to endure and it is difficult to form a good groove.

Therefore, the grooves can be provided with a quadrangular cross section according to claim 5 and the corner portion on the opening side can be chamfered (claim 5).
In the case of this groove having a quadrangular cross section, it is easy to chamfer the corner portion at the same time as the groove is formed, and thus the corner portion is chamfered so that the seal ring can be removed from the holding groove. When the protrusion is caused, the protrusion can be prevented from being damaged by the corner portion of the groove.

In addition, the piping joint of this invention can be used suitably as a piping joint for resin piping.
The pipe joint includes a lock ring, and the pipe can be prevented from being pulled out by causing the claw of the lock ring to bite into the pipe (the outer peripheral surface or the inner peripheral surface of the pipe).
Further, in the pipe joint of the present invention, before inserting the pipe into the inner cylinder part, the seal ring protrudes from the outer peripheral surface of the inner cylinder part by a predetermined dimension radially outward, and the pipe is inserted into the inner cylinder part. The seal ring can be compressed in the radial direction between the inner peripheral surface of the pipe and the outer peripheral surface of the inner cylinder portion, specifically, the groove bottom surface of the holding groove, and can be sealed.
In this case, a coil spring (a seal ring lifting prevention spring) is attached to the outer peripheral side of the inner cylinder part so as to cover the seal ring from the outside in the radial direction, and the pipe is inserted into the inner cylinder part by the pipe. A part of the seal ring in the circumferential direction can be prevented from floating radially outward from the holding groove by a radially inward contact with the seal ring of the coil spring.
Here, it is preferable that the projecting dimension of the seal ring radially outward is 0.3 mm or more.
The pipe joint may have an outer cylinder part and form an annular insertion space between the inner cylinder part and the inner cylinder part.

It is sectional drawing of the piping joint which is one Embodiment of this invention. It is sectional drawing which showed the piping joint of FIG. 1 in the piping connection state. It is the figure which decomposed | disassembled and showed the piping coupling of the embodiment to each component. It is a principal part enlarged view of the embodiment. It is action explanatory drawing which showed the piping joint of the embodiment compared with the conventional one. It is a figure of the principal part of other embodiment of this invention. It is the figure which showed the cancellation | release operation member which can be used in this embodiment. It is a figure for demonstrating the malfunction in the conventional piping joint. It is a figure which shows an example of the piping joint which concerns on the prior application of this invention. It is explanatory drawing which showed typically a mode that piping pinched the foreign material.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 3, 10 is a pipe joint for resin piping, 12 is a metal joint body, and has a flange-shaped large-diameter tool hook portion 14. On the outer peripheral surface on the right side, there is a male screw portion 16 as a connection portion with a pipe on the other side to which a pipe 20 described later is connected.
Further, a cylindrical inner tube portion 18 is integrally provided on the left side in the drawing opposite to the male screw portion 16.
And the resin-made piping 20 is extrapolated to this inner cylinder part 18 in the axial direction, and it connects to the state which fits the inner cylinder part 18 in the piping 20 inside.
Here, a pair of holding grooves 22-1 and 22-2 forming an endless ring along the outer peripheral surface of the inner cylinder part 18 are formed on the outer peripheral surface of the inner cylinder part 18 with an interval in the axial direction. O-rings 24-1 and 24-2 as seal rings having elasticity are fitted and held therein.
Here, the holding grooves 22-1 and 22-2 are formed in a quadrangular cross section.

Reference numeral 26 denotes an outer cylinder portion provided in the pipe joint 10, which is composed of an outer sleeve 28 and an inner sleeve 30, and an annular insertion space for inserting the pipe 20 between the inner sleeve 30 and the inner cylinder portion 18. 32 is formed.
Here, the inner sleeve 30 is made of a translucent resin member, while the outer sleeve 28 is provided with an opening window 33, and the opening window 33 passes through the inner sleeve 30 to enter the insertion space 32. The insertion depth of the pipe 20 can be confirmed.

The outer sleeve 28 has a female threaded portion 34 at the right end in the figure, and the female threaded portion 34 is screwed and fixed to the male threaded portion 36 of the joint body 12.
The outer sleeve 28 is formed with a stepped first sandwiching portion 38, and the first sandwiching portion 38 is made of a metal together with a second sandwiching portion 39 constituted by the end of the inner sleeve 30. A ring base 42 (see FIG. 3) of the disc spring-shaped lock ring 40 is sandwiched and held in the axial direction via a washer 41.
As shown in FIG. 3, the lock ring 40 has a flat ring base portion 42 that forms an annular shape that is continuous in the circumferential direction, and a shape that projects obliquely inward in the radial direction from the ring base portion 42 toward the insertion direction of the pipe 20. Thus, it has a plurality of claws 44 formed side by side in the circumferential direction along the ring base portion 42 and bites the claws 44 into the outer surface of the pipe 20 inserted into the insertion space 32 as shown in FIG. Then, the pipe 20 is locked in the retaining state.

1 to 3, reference numeral 46 denotes a metal coil spring fitted on the inner cylindrical portion 18 on the outer peripheral side of the O-rings 24-1 and 24-2 (preventing lifting of the O-rings 24-1 and 24-2. Spring).
As shown in FIG. 3, the coil spring 46 includes a closely wound portion 50 formed by tightly winding without forming a gap between adjacent circular wires 48 and 48, and the wires 48 and 48. And a loosely wound portion 52 that is sparsely wound in a state in which a gap is formed, and the densely wound portion 50 is disposed on the side of the distal end surface 20A (see FIG. 1) of the pipe 20 before insertion, and is also loosely wound. With the portion 52 positioned on the opposite side, it is fitted on the outer peripheral side of the O-rings 24-1 and 24-2.

When the pipe 20 is inserted into the insertion space 32 and the inner cylinder portion 18 is fitted into the pipe 20, the coil spring 46 is inserted into the O-rings 24-1 and 24-2 at the tip of the pipe 20. It functions to prevent part of the circumferential direction from floating up from the O-ring grooves 22-1 and 22-2.
Specifically, when the pipe 20 is inserted, the O-rings 24-1 and 24-2 are covered with the densely wound portion 50 from the outer peripheral side, and a part of the O-rings 24-1 and 24-2 in the circumferential direction is a holding groove. When trying to float up from 22-1 and 22-2, the tightly wound portion 50 is brought into contact with the portion to be lifted inward in the radial direction, and the circumferential direction of the O-rings 24-1 and 24-2 A part is prevented from floating from the holding grooves 22-1 and 22-2.

  As shown in FIGS. 1 and 3, the outer cylindrical portion 26 in the pipe joint 10, specifically the inner peripheral surface of the inner sleeve 30, has a large diameter portion 54 on the back side on the right side of the insertion space 32 in the drawing. Further, the insertion side on the left side in the drawing is a small diameter portion 56, and a stepped portion 58 is formed between them.

On the other hand, as shown in FIG. 3, the coil spring 46 also has a large diameter portion 60 on the right side and a small diameter portion 62 on the left side in the drawing, and the diameter from the large diameter portion 60 to the small diameter portion 62 therebetween. A transition portion 63 having an intermediate diameter is formed.
As a result of the configuration, the coil spring 46 is prevented from falling off from the pipe joint 10 when the large diameter portion 60 hits the stepped portion 58 of the inner sleeve 30 in a state of being fitted to the pipe joint 10. The
As shown in FIG. 1, the coil spring 46 is fitted to the fitting protrusion 65 of the joint body 12 in an externally fitted state at the right end in the drawing having a large diameter.

1 to 3, reference numeral 64 denotes an unlocking portion for releasing the lock by the lock ring 29, which has a circular ring shape, and is axially along the outer cylindrical portion 26, specifically, the inner peripheral surface of the outer sleeve 28. It is provided so that it can move forward and backward.
The unlocking portion 64 serves to release the claw 44 from the outer surface of the pipe 20 by expanding the claw 44 of the lock ring 40 by a forward movement in the axial direction, specifically, rightward in the drawing. That is, it functions to release the lock of the pipe 20 by the lock ring 40.
The unlocking portion 64 is prevented from coming off in the axial direction by a stopper portion 66 formed in an annular shape on the inner peripheral surface of the outer sleeve 28.

  The unlocking portion 64 is located on the left side in the figure with respect to the lock ring 40, that is, on the front side position in the insertion direction of the pipe 20 with respect to the lock ring 40, and the claw 44 of the lock ring 40 is directed leftward in the figure. When trying to deform by a pulling force, it also functions as a backup ring that abuts on the claw 44 and prevents excessive deformation.

  Here, the unlocking portion 64 protrudes radially inward from the inner peripheral surface of the outer sleeve 28 at the left end in the figure. That is, in the portion of the opening 68 at the left end of the outer sleeve 28 in the drawing, an annular gap S (see FIG. 5) formed between the inner peripheral surface at the left end of the outer sleeve 28 in the drawing and the outer peripheral surface of the pipe 20 in the inserted state. 2)) so as to face in the axial direction.

  In this embodiment, as shown in FIGS. 1 and 2, a detection groove (groove) 70 is formed on the outer peripheral surface of the inner cylindrical portion 18 at a position close to the right side of the holding groove 22-2 in the drawing. 2 (but may be substantially parallel). That is, in the insertion direction of the pipe 20, a detection groove 70 having an endless annular shape (annular shape) is provided along the outer peripheral surface of the inner cylindrical portion 18 at the rear side position of the holding groove 22-2.

  The detection groove 70 is formed so that an O-ring 24-2 (or O-ring 24-2 and 24-1; only the O-ring 24-2 will be described below) from the pipe 20 when the pipe 20 is inserted into the inner cylindrical portion 18 is inserted. In response to the force, a part of the circumferential direction floats radially outward from the holding groove 22-2 (or holding grooves 22-2 and 22-1; only the holding groove 22-2 will be described below), and When a part of the protrusion is pushed out of the holding groove 22-2 with elastic deformation in the axial direction, the protrusion 72 (see FIG. 5A) is overlapped with the detection groove 70 in the radial direction. As a result, a gap is created between the O-ring 24-2, specifically, the protruding portion 72 and the outer peripheral surface of the inner cylindrical portion 18. For this purpose, the detection groove 70 is formed in the O-ring 24-2. The part is located at a position that can be reached when it is elastically deformed in the axial direction. .

When the O-ring 24-1 generates the protruding portion 72 and overlaps the detection groove 70, the detection groove 70 also functions as a detection groove for the O-ring 24-1.
However, the O-ring 24-1 is more axially separated from the detection groove 70 than the O-ring 24-2, and the protruding portion 72 of the O-ring 24-1 does not reach the detection groove 70 and does not overlap therewith. In some cases, this may occur depending on the distance between the holding groove 22-1 and the detection groove 70.
However, even in this case, the protruding portion 72 of the O-ring 24-1 usually overlaps with the adjacent holding groove 22-2, and a gap is formed there. Therefore, the sealing performance by the O-ring 24-1 is provided by the gap. Lost and causes water leakage there.

On the other hand, with respect to the O-ring 24-2 on the rearmost side, that is, the right side in the drawing, if the detection groove 70 is not provided on the rear side, that is, the right side in the drawing, the protruding portion 72 is in close contact with the outer peripheral surface of the inner cylindrical portion 18 and sealed. There is a risk of functioning.
Therefore, in the present invention, when the plurality of holding grooves 22 and the O-ring 24 are arranged adjacent to each other, the detection groove 70 is provided further on the rear side, that is, on the right side in the drawing with respect to the holding groove 22 at the rearmost position. It is effective to keep it.
However, in the case where the plurality of holding grooves 22 and the O-ring 24 are provided in the inner cylinder portion 18, they are provided with a certain interval in the axial direction, and a plurality of detection grooves 70 are respectively provided corresponding to the holding grooves 22. It can also be provided at a position behind each holding groove 22.

The detection groove 70 is disposed at a position close to the holding groove 22-2 at a distance smaller than the width of the O-ring 24-2 from the holding groove 22-2.
More specifically, here, as shown in FIG. 4, the width of the O-ring 24-2 (d ₂ = 1.0 mm away from the cross-sectional diameter d ₁ = 1.8 mm is disposed at a close position). .
In this embodiment, the holding grooves 22-1 and 22-2 are formed with the same shape and the same size, and the O-rings 24-1 and 24-2 are also formed with the same shape and the same size.

As shown in FIG. 4B, in this embodiment, the O-ring 24-2 is positioned more radially than the holding groove 22-2, that is, the outer peripheral surface of the inner cylindrical portion 18, before the pipe 20 is inserted. It is allowed dimension _{h 2} projects.
The O-ring 24-2 (the same applies to the O-ring 24-1) is formed in the radial direction by the inner peripheral surface of the pipe 20 and the bottom of the holding groove 22-2 when the pipe 20 is extrapolated to the inner cylinder portion 18. It compresses and seals between the outer peripheral surface of the cylindrical part 18 and the inner peripheral surface of the piping 20 in a watertight manner.

In this embodiment, the dimension h ₂ = 0.45 mm. Dimension _{h 2} in the present invention it is desirable to at least 0.3mm or more.
In this embodiment, the groove depth h ₁ of the holding groove 22-2 is 1.35 mm.

As shown in FIG. 4B, the detection groove 70 has a quadrangular cross section, and the corner (edge) 74 on the opening side has a circular chamfered shape.
Here, the detection groove 70 has a groove width d ₃ = 1.6 mm, and a groove depth h ₃ = 0.34 mm.
Further, the corner 74 has a circular chamfered shape with a radius R = 0.2 mm.
Here, it is desirable that the arc shape (R shape) of the corner portion 74 is an arc shape having a radius of 0.1 mm or more.

  In the case of a conventional pipe joint, even when a part of the circumferential direction of the O-ring 204 protrudes as shown in FIG. 5B as described above, the protruding portion 72A is the inner cylinder portion. In rare cases, it may be in close contact with the outer peripheral surface of 200 and exert a sealing function.

However, in this embodiment, when a part of the O-ring 24-2 protrudes when the pipe 20 is inserted, the protruding portion 72 is caught in the detection groove 70 as shown in FIG. As a result, a gap due to the detection groove 70 is generated between the protruding portion 72 and the inner cylinder portion 18.
Therefore, when water is passed through the pipe 20 and the pipe joint 10 in that state and a water flow inspection is performed, water in the pipe 20 leaks to the outside through the detection groove 70.
As a result, it is immediately possible to know that a part of the O-ring 24-2 is protruding.

  As described above, according to the present embodiment, when the pipe 20 is inserted into the inner cylindrical portion 18, a part of the O-ring 24-2 in the circumferential direction is lifted, and the shaft is further inserted by inserting the pipe 20. When the protrusion 72 is pushed in the direction and protrudes from the holding groove 22-2 with the elastic deformation in the axial direction, the protrusion 72 is overlapped with the detection groove 70 in the radial direction, so that the outer periphery of the protrusion 72 and the inner cylindrical portion 18 is increased. A gap is formed between the surface and the detection groove 70, and therefore water leakage can be surely caused when a water flow inspection is performed in that state.

  Therefore, although the O-ring 24-2 protrudes from the holding groove 22-2, the sealing function is rarely exhibited, and after that, after a long period of use, the sealing performance is lost for some reason. It is possible to prevent the occurrence of problems such as the occurrence of an O-ring 24-2 at an early stage, and to prevent a problem that leads to a large amount of water leakage due to water leakage after a long period of time. it can.

  In the present embodiment, since the detection groove 70 is provided at a position close to the holding groove 22-2 at the same distance over the entire circumference, any part of the O-ring 24-2 in the circumferential direction is protruded. The protrusion of the O-ring 24-2 can be detected by reliably overlapping the detection groove 70.

  Further, since the detection groove 70 is narrower than the width of the O-ring 24-2, the protruding portion 72 of the O-ring 24-2 can be prevented from being fitted into the detection groove 70. A gap can be surely formed between the protruding portion 72 of the O-ring 24-2 and the outer peripheral surface of the inner cylinder portion 18 in the groove 70.

  Since the corner portion 74 on the opening side of the detection groove 70 has a chamfered shape, the protruding portion 72 of the O-ring 24-2 can be prevented from being damaged and damaged at the edge portion. When the water leakage is noticed, the pipe 20 is once removed, and the same O-ring 24-2 is connected to the pipe joint 10 again by using the same O-ring 24-2. It is possible to eliminate the fear that water is leaked due to insufficient sealing by the ring 24-2.

FIG. 6 shows another embodiment of the present invention.
In this example, the detection groove 70 is a groove having a V-shaped cross section.
Also in the embodiment of FIG. 6, the groove width of the detection groove 70 is narrower than the width of the O-ring 24-2.
In this embodiment, the corner portion of the detection groove 70 is not particularly chamfered.
Also in the embodiment shown in FIG. 6, it is possible to prevent the protruding portion 72 of the O-ring 24-2 from fitting into the detection groove 70 and filling the protruding portion 72 into the groove and sealing it.

FIG. 7 shows a release operation member for releasing the lock of the pipe 20 by the lock ring 40 by pushing the lock release portion 64 in the pipe joint 10 in the right direction in the figure, and here the sizes are different. Three types of release operation members 76-1, 76-2, and 76-3 for the pipe 20 are connected by a connecting portion 78, and these are formed as an integral release operation member unit 80.
Each of the release operation members 76-1, 76-2, and 76-3 has a generally circular shape as a whole, and has a form in which a part in the circumferential direction is cut away. In the figure, reference numeral 81 represents the notch.

Each release operation member 76-1, 76-2, 76-3 has a substantially cylindrical pressing portion 82 and a flange portion 84, which are inserted toward the lock release portion 64 from the gap S in FIG. is doing.
As shown in FIG. 7C, the unlocking operation members 76-1, 76-2, and 76-3 are each pressed by the pressing part 82 in the right direction in the drawing, thereby releasing the lock releasing part 64. Thus, the claw 44 of the lock ring 40 is expanded, and the lock of the pipe 20 by the lock ring 40 is released.

These release operation member units 80 are entirely made of resin, and the release operation members 76-1, 76-2, and 76-3 can be elastically deformed in the radial direction by the notches 81.
Therefore, any one of the three types of release operation members 76-1, 76-2, 76-3 is elastically fitted to the pipe joint 10 so that the release operation member unit 80 can be placed there at the construction site. Can be stored.
For this purpose, the pipe joint 10 is provided with a groove 86 (see FIG. 1) for fitting the release operation members 76-1, 76-2, 76-3.

Although the embodiment of the present invention has been described in detail above, this is merely an example.
For example, the lock ring 40 provided in the pipe joint 10 is merely an example, and the present invention can be applied to pipe joints using other various lock rings.
Further, the lock ring may be one in which a claw is cut into the outer peripheral surface of the pipe to prevent the pipe 20 from being removed, or a pipe 20 is prevented from being pulled out by having a claw in the inner peripheral surface. May be.
In the above example, the detection groove 70 is provided only in one place, but it is also possible to provide a detection groove on the rear side of each corresponding to each O-ring.
Furthermore, the present invention can be applied to various types of pipe joints other than the above examples, and the present invention can be configured in various modifications without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Piping joint 12 Joint body 18 Inner cylinder part 20 Piping 22-1 and 22-2 Holding groove 24-1 and 24-2 O-ring 70 Detection groove (groove)
74 Corner

Claims (5)

The pipe body is extrapolated in the axial direction, and the joint body is provided with an inner cylinder portion that fits in an internally fitted state with respect to the pipe.
On the outer peripheral surface of the inner cylinder portion, a seal ring made of an elastic body is held in a holding groove having an endless annular shape along the outer peripheral surface, and the inner peripheral surface of the pipe and the inner cylinder portion In a pipe joint that is sealed watertight with the seal ring between the outer peripheral surface of
The rear position of the holding groove in the pipe insertion direction, and a part of the seal ring held in the holding groove in the circumferential direction is detached from the holding groove, along the outer peripheral surface of the inner cylinder portion. When projecting in the insertion direction, an endless annular shape is formed along the outer peripheral surface of the inner cylinder portion at a position adjacent to the projecting portion, and a groove substantially parallel to the seal ring is provided. Piping joint.   2. The pipe joint according to claim 1, wherein the groove is provided at a position close to the holding groove at a distance smaller than the width of the seal ring from the holding groove.   The pipe joint according to any one of claims 1 and 2, wherein the groove has a groove width narrower than a width of the seal ring.   4. The pipe joint according to claim 3, wherein the groove is a groove having a V-shaped cross section.   4. The pipe joint according to claim 3, wherein the groove has a quadrangular cross section and a corner portion on the opening side is chamfered.

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