JP4609758B2 - Pipe fitting - Google Patents

Description

  The present invention relates to a pipe joint used for connecting a stainless steel pipe for water supply or hot water supply at a construction site.

  Stainless steel pipes are often used as piping for water supply or hot water supply in consideration of corrosion resistance. As pipe joints for connecting the stainless steel pipes, pipes having various structures such as a press system, a pipe expansion system, and a rolling screw system have been put to practical use.

  The press-type pipe joint has a structure in which an expanded receiving port into which a connecting pipe can be inserted is formed at both ends of the joint, and an O-ring is fitted into an annular groove formed in the opening edge of the joint. After inserting the connecting pipe into the receiving port, piping is performed by caulking the receiving port with a dedicated press tool (large electric tool). This pipe joint is simple in structure, but requires a dedicated tool for construction. In addition, since the operator may forget the caulking process, for example, the pressure-sensitive coloring tape coated with pressure-sensitive coloring paint is coated on the caulking portion of the receptacle, and the discriminating power is given by the pressure when caulking with a press tool. If special measures such as coloring are not used (see Patent Document 1), an accident such as the connection pipe coming out will be caused.

  According to the expansion type pipe joint, after attaching the cap nut to the connection pipe, the end of the connection pipe is expanded with a special tool (large power tool) to form an annular protrusion, and the tip of this protrusion is By inserting the O-ring into the joint main body and then tightening the cap nut, the connecting pipe is advanced and the O-ring is compressed by the annular projecting portion (see Patent Document 2). According to this pipe joint, a dedicated large-sized electric tool is required for construction, and it is necessary to perform pipe expansion processing on the end of the connecting pipe before screwing the cap nut into the joint body. There is a difficulty of becoming. Furthermore, even if the cap nut is not tightened sufficiently, water leakage may be prevented by the O-ring. Therefore, insufficient tightening of the cap nut is not detected by the water pressure test (or atmospheric pressure test), and water leaks after completion of construction. May occur.

  Rolled screw type pipe joints have a tapered female thread at the open end, a joint body with a seal material (O-ring) smaller in diameter than the connecting pipe at the back of the female thread, a male thread part, and a crest of the male thread part. A plurality of small metal discs (abacus ball-shaped members) are embedded along the retainer so as to protrude outward. According to this pipe joint, by screwing the retainer into the joint body, the small disk bites into the connecting pipe (the rolling screw is formed on the connecting pipe by the planetary rotation of the small disk), and the retaining is performed, and The sealing material is compressed to prevent fluid leakage (see Patent Document 3). However, even in this pipe joint, even if the retainer is forgotten to be tightened, it is not detected by the water pressure test, and the connection pipe may come out after the construction is completed and a large water leak may occur. In addition, even if the sealing material has a minute scratch due to the burr at the tip of the connecting pipe, it may not be detected by the water pressure test, and water leakage may occur after several days after the completion of construction.

  Furthermore, a one-touch type pipe joint (refer to Patent Document 4) is put into practical use as a solution to the problems of the above three methods (poor workability and disconnection of connection pipe or water leakage due to poor work). ing. In this pipe joint, an O-ring is fitted into two circumferential grooves provided on the inner surface of the large-diameter portion of the base body, a coil spring is fitted to the edge of the large-diameter portion, and a pressing member having a right-angled edge is fitted to the inner surface. An inner collar made of synthetic resin is disposed, and has a structure in which these are covered with a tapered outer collar. According to this pipe joint, when the connecting pipe is inserted from the tip of the inner collar, the pressing member is pushed to the tip side of the inner collar, but the outer surface of the pressing member is pressed by the tapered surface of the outer collar, Since the right-angled edge of each bites into the connecting pipe, the coupling between the pipe joint and the connecting pipe is maintained. When a pulling force acts on the connecting tube in this coupled state, the pressing member is pressed against the tapered portion side of the outer collar by the elastic force of the coil spring, and the edge of the pressing member presses the connecting tube by the tapered portion, Pulling of the connecting pipe is prevented. By pressing the tip of the inner collar inward from this coupled state, the pressing member is released from contact with the outer collar, and the connecting tube can be pulled out.

JP 2004-84713 A (pages 4-5, FIGS. 1-4) Japanese Patent Application Laid-Open No. 2002-228062 (pages 3 to 5, FIGS. 1 and 2) Japanese Patent Laid-Open No. 10-231967 (pages 2 and 3, FIG. 1) Japanese Patent Laid-Open No. 10-122460 (pages 3 to 5, FIG. 1)

  According to the above-mentioned one-touch type pipe joint, a dedicated tool and pipe end machining are not required, so the workability is excellent. However, because the coil spring is used, the distance between the faces of the pipe joint becomes long, and the joint There is a drawback that the manufacturing cost of the product increases. In addition, since the pressing member is locked by soft touch due to the reaction force of the coil spring, when the water pressure is applied after the construction and a tensile force acts on the connecting pipe, the pressing member is reduced in diameter along the tapered surface of the outer collar, And it moves about several mm in the direction that the connecting pipe comes out. Therefore, in a normal pipe having a plurality of connecting portions, there is a problem that the connecting pipe is bent at each connecting portion, the axial centers of the connecting pipes do not coincide with each other, and the pipe lacks independence.

  Therefore, the object of the present invention is to eliminate the above-mentioned problems, have excellent workability, and prevent the connection pipe from coming out even if the pressing of the press ring is omitted, and to obtain a pipe having a self-supporting property. It is to provide a joint.

In order to achieve the above object, a pipe joint of the present invention includes a joint body incorporating a seal member, a push ring externally mounted on the joint body, an elastic member compressed by a pushing operation of the push ring, and the seal member A movable member that moves the seal member to a position that is in close contact with the outer peripheral surface of the connecting pipe while holding the pipe, and a retaining member that is locked to the outer peripheral surface of the connecting pipe,
The movable member includes a flange portion sandwiched between the seal member and the elastic member, and a ring portion that is provided integrally with the flange portion so as to be separable from the flange portion, and holds the seal member. The ring portion is separated by the pushing operation of the push wheel .

  Further, the pipe joint of the present invention includes a joint main body incorporating a seal member, a push ring externally mounted on the joint main body, an elastic member compressed by a pushing operation of the push ring, and the seal member while holding the seal member. A pipe joint having a movable member that moves a member to a position in close contact with the outer peripheral surface of the connection pipe, and a retaining member that is locked to the outer peripheral surface of the connection pipe,
  The movable member includes a flange portion sandwiched between the seal member and the elastic member, and a ring portion that is locked to the flange portion and holds the seal member, and the flange portion and the ring portion are They are separated by the pushing operation of the push wheel.

  In the present invention, the ring portion is a throttle ring portion having a size capable of holding the seal member in an uncompressed state, and the throttle ring portion has an inner diameter of the seal member by inserting the connecting pipe. It can be set as the structure deform | transformed in the extending direction.

  In the present invention, it is preferable that the elastic member is a compression coil spring having a truncated cone shape formed by winding a wire so that the outer diameter increases from one end to the other end.

  In the present invention, it is preferable that the compression coil spring is compressed to a height substantially equal to a wire diameter when the pusher wheel is pushed to a predetermined position.

  In the present invention, the retaining member is a plurality of members having wedge-shaped protrusions that bite into the connecting pipe on the inner peripheral surface thereof, and is held by the cylindrical inner collar along the substantially circumferential direction. Is preferred.

  In the present invention, it is preferable that a stop ring that is fitted into the push ring by the pushing operation is attached to the joint body.

  In the present invention, it is preferable that an indicator concealed by the pushing operation is attached to the joint body.

  According to the pipe joint of the present invention, the seal member is brought into close contact with the connecting pipe and the retaining member bites into the connecting pipe simply by pushing the push ring. Stop power is obtained. In addition, when the retaining member bites into the connection pipe, the axis of the connection pipe and the axis of the joint body coincide with each other, so that self-supporting properties can be ensured.

  In addition, when there is a construction failure such as forgetting to push the push wheel and insufficient tube insertion length, it is possible to surely generate a slight leak during the water pressure test and to detect the construction failure.

  In particular, by supporting the inner peripheral side of the seal member with the ring part of the movable member, even if there is a construction failure such as forgetting to remove the pipe end burr, the seal member does not come into contact with the pipe end. It is prevented and sealability can be secured.

(First embodiment)
FIG. 1 is a half sectional view of a pipe joint according to the first embodiment of the present invention. The left half shows a state before inserting a connecting pipe, the right half shows a state where a connecting pipe is inserted, and FIG. Is a half cross-sectional view of the pipe joint during and after construction, the left half shows the state where the pusher wheel is pushed halfway and the movable member is slid, the right half shows the state where the pusher wheel is pushed completely, FIG. FIG. 4 is a perspective view of the movable member, and FIG.

  As shown in FIG. 1, the pipe joint 1 includes a joint body 2 having a socket shape with both ends opened, a pusher wheel 3 attached to the outer periphery thereof, and a seal member 4 attached to the inside of the joint body 2. I have. As the sealing member, a rubber O-ring can be used as shown, and a lip packing or a metal member exhibiting low elasticity can be used instead of the O-ring. The joint body 2 includes a first step portion 21 that receives a part of a movable member to be described later on the inner peripheral side, a tapered surface 22 that faces the seal member 4, and a second step formed from there toward the back side. It has the part 23 and the 3rd step part 24 of a smaller diameter than it. Two circumferential grooves 25 and 26 are formed on the outer periphery of the joint body 2. The pusher wheel 3 has a straight cylindrical portion 31 and a tapered portion 32 that slopes downward from the straight cylindrical portion 31, and a tapered circumferential groove 33 and a circumferential groove at a position spaced from the tapered circumferential groove 33 are formed on the inner peripheral surface of the straight cylindrical portion 31. 34 is formed. A movable member 5 adjacent to the seal member 4, an elastic member 6 that presses the movable member 5, a retaining member 8 that is inscribed in the tapered portion 32, and an inner collar 7 that supports the movable member 5 are disposed inside the pusher wheel 3. As the elastic member 6, for example, a substantially frustoconical compression coil spring provided so that the large-diameter side thereof is in contact with the movable member 5 is used. A stop ring 9 is fitted into the circumferential groove 25 of the joint body 2 so as to partially protrude therefrom, and the circumferential groove 26 of the joint body 2 has a ring shape for confirming the completion of connection. The indicator 10 is fitted.

  As shown in FIGS. 3 and 4, the movable member 5 includes a ring portion 53 having a flange portion 51 having a stepped portion 52 formed on the inner periphery and a plurality of protrusions 54 along the circumferential direction on the outer periphery of the end portion. In addition, a circumferential groove 55 is provided in the neck portion of the flange portion 51 so that the ring portion 53 is thin. The elastic member 6 is a substantially frustoconical spring formed by winding a wire so that the outer diameter increases from one end to the other end, and the larger diameter side is provided on the inner circumference of the flange portion 51. The step 52 is held. The inner collar 7 includes a flange portion 71 and a ring portion 72, and a plurality of retaining members 8 having two wedge-shaped protrusions 81 on the inner peripheral surface are fixed to the ring portion 72 along the circumferential direction. . Further, the substantially frustoconical compression coil spring can be provided so that the small diameter side thereof is in contact with the flange portion 51 of the movable member 5, contrary to the state shown in FIG. 1.

  In this invention, the member which comprises the pipe joint 1 can be formed with the following material, for example. Since the joint body 2 requires corrosion resistance and rigidity, it can be formed by a precision casting technique using, for example, an SCS material or a bronze material. Since the press wheel 3 also needs corrosion resistance and rigidity, it is formed by a precision casting method using, for example, an SCS material, or a plastic working method such as hot forging, cold forging, or press forming using austenitic stainless steel. can do. The seal member 4 can be formed of an olefin rubber, and is preferably formed of EPDM, which is a terpolymer of ethylene, propylene, and a diene monomer for crosslinking, which is particularly excellent in heat resistance. At the same time, it can be formed of FKM (fluororubber) having excellent chemical resistance. The movable member 5 can be formed of polyolefin such as crosslinked PE. The inner collar 7 can be formed of a general engineering plastic such as POM (polyacetal) or a special engineering plastic such as PPS (polyphenylene sulfide) having excellent heat resistance. When a compression coil spring is used as the elastic member 6, this member can be formed of austenitic stainless steel (SUS304), and the stop ring 9 can also be formed of the same material. The retaining member 8 may be formed of a material harder than the connecting pipe, for example, martensitic stainless steel (SUS420) when the connecting pipe is austenitic stainless steel (SUS304). As the ring-shaped indicator 10, for example, a ring-shaped molded body made of polyolefin such as PE or PP, or a film-shaped tape excellent in weather resistance can be used. Moreover, not only this but it can be set as an indicator by apply | coating an oil-based coating material to the coupling main body 2. FIG.

  The construction procedure of the connecting pipe 11 by the pipe joint 1 will be described with reference to FIGS. First, as shown in the left half of FIG. 1, all the parts including the push ring 3 are assembled into the joint body 2, and then the connecting pipe 11 (for example, SUS304 steel pipe) is inserted as shown in the right half of FIG. The end surface is brought into contact with the inner peripheral side end surface of the ring portion 53 of the movable member 5. At this time, the retaining member 8 moves toward the center side of the joint body 2 while being expanded in diameter along the tapered portion 32 of the pusher wheel 3, and the wedge-shaped projection 81 is locked to the connecting pipe 11. Even if an external force is applied in the direction in which the connection tube 11 is pulled out in this state, the wedge-shaped protrusion 81 of the retaining member 8 that is inscribed in the tapered portion 32 of the pusher wheel 3 is locked to the outer peripheral portion of the connection tube 11. The tube 11 is not pulled out.

  Next, by pushing the pusher wheel 3 toward the center of the joint body 2, a seal connection between the joint body 2 and the connecting pipe 11 is performed as shown in FIG. 2. In FIG. 2, the reference numerals of the first step portion 21 and the third step portion 24 of the joint body 2 are omitted for easy understanding. More specifically, when the pusher wheel 3 is pushed halfway into the joint body 2, the connecting pipe 11 is in a state where the wedge-shaped protrusion 81 of the retaining member 8 is locked to the outer periphery of the connecting pipe 11 as shown in the left half of FIG. 2. Is pulled to the back of the joint body 2, the ring portion 53 of the movable member 5 is in contact with the back end surface of the third step portion 24 of the joint body 2, and the flange portion 51 is the first step portion of the joint body 2. 21 abuts against the back end face of 21. Moreover, since the flange portion 71 of the inner collar 7 moves to the center side of the joint body 2, the elastic member 6 is compressed to the same thickness as the wire diameter by being sandwiched between the flange portion 71 and the flange portion 51. During the push-in operation of the pusher wheel 3, the movable member 5 is divided by a circumferential groove 55 (see FIG. 4) present in the neck part of the flange part 51, and between the neck part of the flange part 51 and the ring part 53. A gap is formed, and the seal member 4 is sandwiched between the gaps, and the seal member 4 is pushed into a region surrounded by the tapered surface 22, the flange portion 51, and the connecting pipe 11, so that a predetermined seal surface pressure is obtained. .

  By pushing the pusher wheel 3 to the end, as shown in the right half of FIG. 2, the retaining member 8 is pressed against the connecting pipe 11 by the inner peripheral side end face of the tapered portion 32 of the pusher wheel 3, and the wedge-shaped protrusion of the retaining member 8. Since 81 bites into the outer peripheral portion of the connecting pipe 11 while giving the connecting pipe 11 some plastic deformation in the radial direction, the connecting pipe 11 is reliably prevented from coming off. Further, since the stop ring 9 enters the circumferential groove 34 of the pusher wheel 3, the pusher wheel 3 is fixed at a predetermined position. Furthermore, since the ring-shaped indicator 10 fitted in the circumferential groove 26 of the joint body 2 is concealed by the pusher wheel 3, it is visually confirmed that the connection is completed.

  When a tensile test for pulling out the connecting pipe is performed after the connecting pipe is connected to the joint, the connecting pipe 11 moves from the right half of FIG. 2 to the right, and the pipe ends of the seal member 4 and the connecting pipe 11 are connected. The seal surface pressure is reliably maintained until the values coincide. Further, since the retaining member 8 bites into the connecting pipe 11, the shaft center of the connecting pipe and the shaft center of the joint body always coincide with each other, so that the self-supporting property can be secured and firmly fixed.

  According to the pipe joint shown in FIG. 1, a pipe cutting process for cutting the connecting pipe to a predetermined length, a marking process for marking the insertion length on the connecting pipe, a final fastening process for tightening the press ring, and the connecting pipe being inserted by a predetermined length. Since the pipe construction can be performed in four processes including the marking confirmation process for confirming that the construction has been performed, the construction time can be greatly reduced as compared with the conventional pipe joint. For example, according to a pipe expansion type pipe joint, a pipe cutting process, a pipe end chamfering process for removing burrs at the pipe end, a nut mounting process for attaching a press ring (nut) to the connecting pipe, a pipe expanding process, and a hand tightening for manually tightening the nut Construction consisting of seven processes, such as a process, a final tightening process for final tightening of the nut, and an indicator confirmation process for confirming the nut tightening amount, is performed. According to the pipe joint of the present invention, the construction time can be reduced by about 60% or more compared to this.

  In addition, according to the rolled screw type pipe joint, construction including six processes such as a pipe cutting process, a pipe end chamfering process, a marking process, a hand tightening process, a final tightening process, and a marking confirmation process is performed. According to this pipe joint, the construction time is shortened by about 25% compared to the pipe expansion type pipe joint. However, according to the pipe joint of the present invention, the construction time can be reduced even when compared with the rolled screw type pipe joint. It can be reduced by about 40% or more.

  According to the pipe joint 1 shown in FIG. 1, even if there is a construction failure, it can be detected in advance by a water pressure test, and problems such as water leakage can be prevented. That is, when the presser wheel 3 is forgotten to be pushed by a predetermined amount, the seal member 4 is not compressed, so that a minute water leak can be detected by the water pressure test, and the retaining member 8 is the reaction force (restoration) of the elastic member 6. Force) is pushed back to the tapered portion 32 side of the pusher wheel 3, so that the connecting pipe 11 is not completely pulled out. For example, the connecting pipe is pulled out due to forgetting to tighten the retainer as occurred in a rolled screw type pipe joint. Is prevented in advance. Further, even when the insertion length of the connecting pipe 11 is insufficient, the connecting pipe 11 does not come into contact with the seal member 4, so that a minute water leak can be detected by a water pressure test. Furthermore, apart from the removal of large burrs, the end face of the connecting pipe 11 is inserted to the back of the joint body in a non-contact state with the seal member 4 even when the pipe end chamfering process is not performed. The seal member 4 is not damaged, and water leakage due to damage to the seal member does not occur unlike a rolled screw type pipe joint.

(Modification of movable member)
In FIG. 1, the movable member 5 is not limited to the above structure, and can have various structures. FIG. 5 is a perspective view showing a second example of the movable member, FIG. 6 is a sectional view showing a state in which the seal member 4 is mounted on the movable member, and FIG. 7 is a state in which a connecting pipe is inserted into the movable member of FIG. The same functional parts as those in FIGS. 3 and 4 are denoted by the same reference numerals. The movable member 5 has a flange portion 51 in which a step portion 52 is formed on the inner periphery, a plurality of protrusions 54 along the circumferential direction on the outer periphery of the end portion, and a shape that is recessed toward the inner diameter side in the middle of the axial direction. And a circumferential groove 55 is provided in the neck portion of the flange portion 51. A plurality of slit portions 57 extending in the same direction as the insertion direction of the connecting pipe (see FIG. 7) are formed in the aperture ring portion 56 along the circumferential direction, and the indented portion of the aperture ring portion 56 is located there. When the seal member 4 is inserted, the seal member is formed in such a size that the diameter is not substantially expanded.

  As shown in FIG. 7, when the connecting pipe 11 is inserted into the movable member 5, the slit ring part 56 has a slit part 57 that opens in a diamond shape, and is substantially the same as the outer diameter of the connecting pipe 11. Since the sealing member 4 is deformed in the radial direction, the sealing member 4 can exhibit a predetermined sealing performance. That is, if a load is applied to the seal member (for example, an O-ring) and left for a long time in a state where it is elastically deformed (expanded), a “sagging phenomenon” occurs (the compression set remains) and the load is removed. However, according to the movable member shown in FIG. 5, in the state where the seal member 4 is mounted on the aperture ring portion 56, the seal member 4 does not return to the original size. Since no internal stress is generated and a seal surface pressure is generated only when the connecting pipe 11 is inserted, an appropriate compression allowance is maintained over a long period of time, and a predetermined service life can be guaranteed.

  FIG. 8 is a sectional view showing a third example of the movable member, and the same functional parts as those in FIGS. 3 and 4 are denoted by the same reference numerals. In the movable member 5, the flange portion 51 and the ring portion 53 are formed as separate members, and the concave portion formed on the inner peripheral side of the end of the ring portion 53 is formed on the convex portion 511 formed on the outer peripheral side of the end of the flange portion 51. 531 has a locked structure. According to this movable member 5, when the flange portion 51 is pushed into the back side (the right side in FIG. 8) of the joint body (not shown), the ring portion 53 is separated from the flange portion 51 and the joint body (not shown). The seal material 4 is held between the ring portion 53 and the flange portion 51 in the same manner as in FIG. Therefore, according to this movable member 5, the same effect as the movable member mentioned above is acquired.

  In addition, although the illustration of the movable member is omitted, the flange portion and the ring portion are formed as separate members, and these are integrally joined with an adhesive or the like so that they are separated by a predetermined load at the time of piping construction. Also good.

(Second Embodiment)
FIG. 9 is a half sectional view of a pipe joint according to the second embodiment of the present invention. The left half shows a state before construction and the right half shows a state after construction. The same functional parts as those in FIG. The description is omitted. In this pipe joint, the movable member 50 is a cone-shaped ring body and is disposed so as to be sandwiched between the elastic member 6 and the inner surface of the end of the joint body 2.

  According to the above configuration, the connection pipe 11 is fixed to the joint body 2 by the same operation as in FIG. Here, after the elastic member 6 is compressed by pushing the push wheel 3, the movable member 50 is deformed into a flat plate shape as shown in the right half of FIG. 5, and the seal member 4 is also crushed. Sealability is ensured.

  In the above description, a symmetric socket-type pipe joint has been described. However, the present invention is not limited to this, and other structures (for example, an elbow-shaped joint, a male thread adapter in which a male thread for connection is formed on one side of the joint body) Needless to say, the present invention can be applied to pipe joints of joints).

It is a half sectional view of a pipe joint concerning a 1st embodiment of the present invention. FIG. 2 is a half cross-sectional view showing a state during and after connection of a connection pipe to the pipe joint of FIG. 1. It is a perspective view of a movable member. It is sectional drawing of a movable member. It is a perspective view which shows the 2nd example of a movable member. It is sectional drawing which shows the state which mounted | wore the movable member of FIG. 5 with the sealing member. It is sectional drawing which shows the state which inserted the connecting pipe in the movable member of FIG. It is sectional drawing which shows the 3rd example of a movable member. It is a half sectional view of a pipe joint concerning a 2nd embodiment of the present invention.

Explanation of symbols

1: pipe joint 2: joint body, 21: first step portion, 22: taper surface, 23: second step portion, 24: third step portion, 25, 26: circumferential groove,
3: push wheel, 31: right cylindrical portion, 32: tapered portion, 33: tapered circumferential groove, 34: circumferential groove 4: seal member 5, 50: movable member, 51: flange portion, 511: convex portion, 52 : Step part, 53: Ring part, 531: Recessed part, 54: Projection part, 55: Circumferential groove, 56: Drawing ring part, 57: Slit part 6: Elastic member 7: Inner collar, 71: Flange part, 72: Ring portion 8: retaining member, 81: wedge-shaped projection 9: stop ring 10: indicator 11: connecting pipe

Claims (3)

A joint body containing a seal member, a push ring externally mounted on the joint body, an elastic member compressed by the pushing operation of the push ring, and the seal member closely contacting the outer peripheral surface of the connecting pipe while holding the seal member A pipe joint having a movable member that is moved to a position to be moved and a retaining member that is locked to the outer peripheral surface of the connection pipe,
The movable member includes a flange portion sandwiched between the seal member and the elastic member, and a ring portion that is provided integrally with the flange portion so as to be separable from the flange portion, and holds the seal member. The pipe joint is separated from the ring portion by the pushing operation of the push wheel . A joint body containing a seal member, a push ring externally mounted on the joint body, an elastic member compressed by the pushing operation of the push ring, and the seal member closely contacting the outer peripheral surface of the connecting pipe while holding the seal member A pipe joint having a movable member that is moved to a position to be moved and a retaining member that is locked to the outer peripheral surface of the connection pipe,
The movable member includes a flange portion sandwiched between the seal member and the elastic member, and a ring portion that is locked to the flange portion and holds the seal member, and the flange portion and the ring portion are The pipe joint is separated by a pushing operation of the push wheel . The ring portion is a throttle ring portion having a size capable of holding the seal member in an uncompressed state, and the throttle ring portion is deformed in a direction of widening the inner diameter of the seal member by inserting the connection pipe. The pipe joint according to claim 1 or 2 , characterized in that:

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