JP2018155268A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is desired to promptly and easily implement fastening work of a nut even at a place where it is difficult to implement the work, in order to reduce a diameter of a collet of which the outer peripheral surface is tapered with the same shape of both sides with a center of a collet axial direction defined as a boundary, and which is formed in a symmetrical shape that both the sides in the collet axial direction become symmetric.SOLUTION: In a pipe joint, a nut 13 that is threaded on an outer peripheral surface of a joint body 11 is fastened, thereby inserting a pipe P and a diameter of an annular collet 12 that is disposed inside of the nut 13 is reduced. The pipe P is fastened and the pipe P is held. The collet 12 is substantially formed in a symmetric shape that both sides in a collect axial direction become symmetric with a center in the collet axial direction defined as a boundary. The pipe joint comprises diameter reduction block parts 18a, 18b and 18c for blocking a diameter reduction operation of the collet 12 at one side in the collet axial direction when fastening the nut 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pipe joint.

For example, a resin piping system for performing piping using a resin pipe in a water supply facility or the like is known. As one of mechanical joints for resin piping constituting this resin piping system, a nut tightening is known. There is a fitting.
As the nut tightening joint, for example, an annular collet (for example, a split ring or C), which is inserted into the nut and inserted inside the nut by tightening a nut screwed to the outer peripheral surface of the joint body on which the pipe is mounted. A structure is adopted in which the diameter of the ring or the like is reduced, the pipe into which the core material of the joint body is inserted is tightened, and the pipe is held in the joint body. When the nut is tightened, the collet is reduced in diameter by moving the inner peripheral surface of the tapered nut in contact with the outer peripheral surface of the tapered collet.

In such a nut tightening joint, when the collet is assembled into the joint body, the collet has a boundary at the center of the collet axial direction in order to prevent an error in the collet reverse assembly that reverses the taper direction. In many cases, both sides are formed in an axially symmetric shape having a taper shape having the same shape (axisymmetric shape).
For example, Patent Document 1 discloses an example in which the outer peripheral surface of the collet is formed in an axially symmetrical shape in which both sides are tapered with the same shape at the center in the collet axial direction.

JP 2011-106538 A

  By the way, there are many places where work such as water supply equipment is difficult to work such as being narrow or difficult to work, and it takes time and effort to tighten the nuts. Often spent. In particular, if the outer peripheral surface of the collet is tapered with the same shape on both sides of the center of the collet axial direction, and the symmetrical shape is symmetrical on both sides of the collet axial direction, the collet shrinks due to tightening of the nut. Since the diameter is generated along with the movement along the tapered surfaces on both sides of the outer peripheral surface, the stroke and the number of rotations for tightening the nut have to be increased.

For this reason, tightening the nut to reduce the diameter of the collet whose outer peripheral surface is tapered with the same shape on both sides of the center of the collet axial direction, and which has a symmetrical shape that is symmetrical on both sides of the collet axial direction It has been desired to be able to work quickly and easily even in places where it is difficult to work.
SUMMARY OF THE INVENTION An object of the present invention is to provide a nut tightening type pipe joint that can prevent a construction error in reverse collet assembly and can reduce labor and time for pipe connection work.

In order to achieve the above object, a pipe joint according to the present invention is formed by tightening a nut screwed onto the outer peripheral surface of a joint body, thereby reducing the diameter of an annular collet disposed inside the nut. In the pipe joint that tightens the tube and holds the tube, the collet is a collet that has a reduced diameter on both sides in the axial direction when tightened, and one side of the collet in the collet axial direction when the nut is tightened A diameter reduction preventing portion is provided to prevent the diameter reduction operation. According to the pipe joint according to the present invention, it is possible to prevent a construction error in reverse collet assembly and to reduce labor and time for pipe connection work.
In the pipe joint according to the present invention, it is preferable that the collet is formed in a symmetrical shape in which both sides of the collet axis direction are symmetric with respect to the center of the collet axis direction. According to this configuration, the collet can be easily manufactured.

In the pipe joint according to the present invention, it is preferable that the diameter reduction preventing portion is a locking portion formed on the joint main body or the nut for locking the collet. According to this configuration, one of the diameter reducing operations on both sides of the collet axial direction can be prevented with a simple configuration.
In the pipe joint according to the present invention, the joint body includes a core member into which the pipe is inserted on the outer peripheral side,
It is preferable that a concave portion is provided at a position corresponding to a position where the collet is crimped to the tube when the collet is reduced in diameter on the outer peripheral surface of the core material. According to this configuration, the tube can be securely clamped and fixed.
In the pipe joint according to the present invention, it is preferable that a tip of the portion where the collet is crimped to the pipe when the collet is reduced in diameter is sharp. According to this structure, a pipe | tube can be fixed reliably.

  According to the present invention, it is possible to provide a nut-tightening type pipe joint that can prevent a construction error in reverse collet assembly and can reduce labor and time of pipe connection work.

It is a disassembled block diagram which shows each component of the pipe joint which concerns on one embodiment of this invention. 1 shows a state in which a pipe is mounted on the pipe joint of FIG. 1 in a cross section by a plane including the axis of the pipe, (a) is a cross-sectional explanatory view before collet diameter reduction, (b) is a cross-sectional explanatory view after collet diameter reduction, (C) is sectional explanatory drawing which expanded the part enclosed with the dashed-two dotted line of (a). FIG. 1 shows another example of the diameter reduction preventing portion provided in the pipe joint of FIG. 1 in a cross section by a plane including the axis of the pipe, FIG. Is a cross-sectional explanatory view of another example 2 of the diameter reduction preventing part, and (c) is a cross-sectional explanatory view of another example 3 of the diameter reduction preventing part.

Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.
As shown in FIG.1 and FIG.2, the pipe joint 10 of this embodiment has the joint main body 11, the collet 12, and the nut 13, and can connect the pipe (pipe) P to a communication state.
In this embodiment, the pipe joint 10 is an annular collet 12 in which the pipe P is inserted and disposed inside the nut 13 by tightening a nut 13 screwed onto the outer peripheral surface of the joint body 11 to which the pipe P is attached. Decreases the diameter, tightens the pipe P, and holds the pipe P in the joint body 11.
The pipe joint 10 of this embodiment is a nut fastening which is one of the mechanical joints for resin piping which comprises the resin piping system for performing piping using the resin pipes P, for example in water supply equipment etc. Functions as a joint.

In this embodiment, the joint main body 11, the collet 12 and the nut 13 constituting the pipe joint 10 are made of metal, but some or all of the joint main body 11, the collet 12 and the nut 13 are made of resin, etc. You may form with members other than a metal. In that case, it is preferable that the joint body 11 and the nut 13 are made of metal and the collet 12 is made of resin.
In the present embodiment, the joint main body 11 is formed in a substantially cylindrical shape, and a core member 14 projects toward an opening at one end side (the right side in FIG. 1). The shape rotation action part 11a and the external thread part 11b are formed (refer FIG. 1). In the present embodiment, the core member 14 is provided with a pipe P inserted on the outer peripheral side and a water stop O-ring 15 for stopping water between the pipe P and the rotation. For example, a tool such as a spanner can be engaged with the operating portion 11a to act on the power, and a nut 13 can be screwed onto the male screw portion 11b (see FIGS. 2A and 2B). b)).

In addition, the core material 14 may not be provided in the joint main body 11. In this case, for example, an O-ring is attached to the outer peripheral surface of the pipe P inserted into the internal space of the male screw portion 11b, and the male screw portion 11b Adhere closely to the inner peripheral surface to make the outer surface still water.
In this embodiment, a pipe socket 16 communicating with the opening protrudes integrally with the joint body 11 at the opening of the joint body 11 on the side opposite to the side on which the core member 14 projects (left side in FIG. 1). (See FIG. 1). By attaching another pipe (not shown) to the pipe socket 16, the pipe P and the other pipe respectively attached to the core member 14 and the pipe socket 16 can be communicated with each other via the pipe joint 10.

  In this embodiment, the collet 12 is a collet that is reduced in diameter on both sides in the axial direction when tightened, and has an annular shape provided with a plurality of notches 17, and the outer peripheral surface is the center of the collet axial direction. It is formed in a symmetric shape in which both sides of the collet axis direction are symmetric, for example, a symmetric shape in which both sides are tapered with the same shape on both sides of the center in the collet axis direction. Here, the symmetric shape includes a shape that is substantially symmetric. Here, “substantially symmetrical” means that, in this embodiment, the collet has a notch 17 that is arranged by alternately reversing the incision direction in the collet axis direction, which will be described later, or the collet is surrounded like a C ring. This means that the structure serving as a skeleton needs to have symmetry, including a case where a part is missing in the direction. In the present embodiment, the tapered shape is a center part 12a having a plane substantially parallel to the collet axis at the center of the collet axis direction, and a downward slope from the center part 12a toward the openings on both sides of the collet axis direction. And has a taper portion 12b that becomes the rotating action portion 11a side when mounted on the joint body 11, and a taper portion 12c that becomes the protruding end side of the core member 14 (FIGS. 1 and 2). (See (a) and (b)).

  In the present embodiment, the taper angle of the tapered portion 12b and the tapered portion 12c of the collet 12 with respect to the collet axis direction is preferably 10 ° to 35 °, and more preferably 15 ° to 25 °. When the taper angle is 15 ° to 25 °, the tightening torque when tightening the nut can be reduced, and when the taper angle is 20 ° to 25 °, the tightening stroke when tightening the nut can be shortened. it can. The tightening torque is lower when the taper angle is closer to the 10 ° side, and the tightening stroke is smaller when the taper angle is closer to the 35 ° side. However, if the taper angle is too close to 10 °, a force is applied so that the collet that bites into the pipe when it is tightened pushes the pipe into the joint back side, and conversely the effect of reducing the tightening torque is reduced.

  The collet 12 is provided with a plurality of notches 17 to form discontinuous portions in the circumferential direction of the collet 12, and can be reduced in diameter so as to be narrowed by pressing the outer peripheral surface (see FIG. 1). The notches 17 of the present embodiment are arranged at a plurality of predetermined intervals in the circumferential direction of the collet 12 (a constant interval in this example), and the cutting directions are alternately reversed in the collet axis direction (see FIG. For example, a split ring, a C ring, or the like that can be reduced in diameter so as to narrow down by forming a discontinuous portion in the circumferential direction and pressing the outer peripheral surface may be used.

Further, in this embodiment, the collet 12 is a pipe P attached to the core member 14 with the inner peripheral surface of the nut 13 screwed to the male thread portion 11b of the joint body 11 and the core member 14 inserted. The shape and size can be arranged in a gap space d formed between the outer circumferential surface and the collet radial direction and the collet axis direction in the gap space d. (See FIGS. 2A and 2B).
Further, in this embodiment, the collet 12 has a tube extending over the entire circumference except for the notches 17 at three locations on the inner peripheral surface opposite to the outer peripheral surface of the tube P inserted into the collet 12 in the center and both ends in the collet axial direction. A ridge 12d protruding to the P side is formed (see FIGS. 1, 2 (a) and (b)). It is preferable that the ridges 12d are provided at least at two locations on both ends of the collet axis direction.

  In the present embodiment, the nut 13 has a tapered taper at one end side (the right side in FIGS. 1, 2 (a) and (b)) which becomes the protruding end side of the core member 14 when attached to the joint body 11. It is formed in a substantially cylindrical shape, and has an internal thread portion 13a that can be screwed to the external thread portion 11b of the joint body 11 on the inner peripheral surface on the other end side, and is screwed to the external thread portion 11b. In a state where the other end side end is in contact with the joint body 11, the one end side end has a length in the nut axial direction that is substantially the same position as the protruding end of the core member 14 (FIGS. 1 and 2). a), see (b)). In the present embodiment, the nut 13 in which the female screw portion 11a is screwed to the male screw portion 11b of the joint body 11 is continuously tightened from the time when the female screw portion 13a and the male screw portion 11b start to be screwed. The distance to the point when the end side end is brought into contact with the joint body 11 is the nut tightening amount s (see FIG. 2A).

  In addition, the opening at the end of one end of the nut 13 (the right side in FIGS. 1, 2 (a) and (b)), that is, the tip opening with a tapered tip, is formed in the joint body 11 of the nut 13 in this embodiment. Is formed to have an inner diameter that allows the core material 14 to be inserted and to be brought into close contact with the outer peripheral surface of the pipe P attached to the joint main body 11. The tapered inner peripheral surface is formed by a tapered portion 13b formed of an inclined surface that gradually increases in diameter toward the other end side (see FIGS. 2A and 2B). When the nut 13 is mounted on the joint body 11, the collet 12 disposed in the gap space d between the inner peripheral surface of the nut 13 and the outer peripheral surface of the pipe P has only one inclined surface 12 c and the tapered portion of the nut 13. 13b (see FIGS. 2A and 2B).

On the other end side of the outer peripheral surface of the nut 13, in the present embodiment, for example, a hexagonal nut-shaped turning action portion 13 c similar to the turning action portion 11 a of the joint body 11 is formed ( (Refer FIG. 1, 2 (a), (b)).
By attaching the nut 13 to the joint body 11 (see FIG. 2A) and tightening, the nut 13 causes the tapered portion 13b to contact the tapered portion 12c of the collet 12 on the protruding end side of the core member 14. As a result, the taper portion 13b and the taper portion 12c come into a sliding contact state in which the taper portion 13b and the taper portion 12c are in contact with each other (see FIG. 2B). It is further pushed into the pipe P side by the part 13b.

  The collet 12 is reduced in diameter by the taper portion 12c being further pushed and narrowed toward the tube P side. As a result, each projecting ridge portion 12d of the collet 12 extends over the entire outer peripheral surface of the tube P passing through the collet 12. Biting in (see FIG. 2B), the pipe P is tightened, and the pipe P is clamped and fixed between the collet 12 and the core member 14 attached to the joint body 11 to which the nut 13 is screwed. (See FIG. 2 (b)).

  As shown in FIG. 2, the pipe joint 10 according to the present embodiment has a diameter reduction preventing portion that prevents the diameter reduction operation on one side (only one side) of the collet 12 when the nut 13 is tightened. Is provided. In the present embodiment, the diameter-reducing prevention portion is an annular axial end portion of the collet 12 formed on the axial end surface of the joint main body 11 facing the collet 12 (here, on the rotating action portion 11a side). (End part) can enter (refer FIG.2 (b)), and it consists of the annular recessed part 18a (refer FIG.2 (c)) corresponding to this end part, and functions as a latching | locking part which latches the collet 12. .

  When the nut 13 attached to the joint body 11 is tightened (that is, moved to the joint body 11 side) by an annular recess 18a as a diameter reduction preventing portion provided in the joint body 11, the core material 14 is inserted. The collet 12 disposed inside the nut 13 in a state in which the pipe P is passed through the end enters the annular recess 18a at the end of the tapered portion 12b side (rotating action portion 11a side) and is locked (see FIG. 2 (b)), the movement to the rotation action part 11a side is prevented. The annular concave portion 18a functions as a locking portion when the end portion of the collet 12 enters and locks, and the collet 12 is locked, so that one side in the collet axial direction (here, the tapered portion 12b side). The diameter-reducing operation can be prevented. For this reason, the collet 12 that is prevented from moving to the rotating action portion 11a side is pushed and squeezed only on the tapered portion 12c side toward the pipe P side on the entire circumferential surface as the nut 13 is tightened. Then, the diameter is reduced (see FIG. 2B).

  That is, the diameter of the collet 12 due to tightening of the nut 13 is not the taper portions 12b and 12c on both sides of the outer peripheral surface of the collet 12, but the movement of the taper portion 13b of the nut 13 along the taper portion 12c only on one side of the outer peripheral surface. Therefore, even if the collet 12 is formed in a symmetrical shape that is tapered with the same shape on both sides with respect to the center in the collet axial direction, the diameter of the collet 12 is reduced by tightening the nut 13. However, as compared with the case where the nut 13 is moved along the tapered surfaces on both sides of the outer peripheral surface of the collet 12, the stroke and the number of rotations for tightening the nut 13 can be substantially halved.

  As described above, in the pipe joint 10 of the present embodiment, the collet 12 has a symmetrical shape in which the outer peripheral surface is tapered with the same shape on both sides with the center of the collet axial direction as a boundary, and both sides of the collet axial direction are symmetrical. Since it is formed into a shape, it is possible to prevent a construction error in reverse collet assembly and reduce the diameter of only the other side without reducing the diameter of one side of the taper (see FIG. 2 (b)). The collet 12 can be reduced in diameter and tightened by the tightening amount. Therefore, labor can be saved in the connection work of the pipe P using the pipe joint 10, and the connection work can be performed quickly and easily even in the pipe connection work in a place where the work is difficult. Can be reduced.

Next, another example of the diameter reduction preventing portion provided in the pipe joint 10 will be described.
As shown in FIG. 3A, in another example 1 of the diameter reduction preventing portion, the diameter reduction preventing portion of the collet 12 formed over the entire circumference of the joint main body 11 in the axial end surface facing the collet 12. An annular ridge 18b corresponding to the groove-like recess 12e, into which the groove-like recess 12e can enter, is used. The groove-like recess 12e of the collet 12 is provided in an annular shape centering on the collet axis over the entire circumference of the end faces on both sides in the axial direction of the collet 12 (see FIG. 3 (a)). By entering and locking in the groove-like recess 12e, it functions as a diameter reduction preventing portion.

  In the configuration in which the annular ridge 18b as the diameter reduction preventing portion is formed in the joint body 11, the annular axial end of the collet 12 formed on the axial end surface of the joint body 11 described above. As with the annular recess 18a through which the portion can enter, the tapered portion 13b of the nut 13 and the tapered portion 12c of the collet 12 come into contact with each other and come into sliding contact with each other. The part 12b side is fixed, and only the taper part 12c side of the collet 12 is pushed and squeezed to the pipe P side on the entire circumferential surface, thereby reducing the diameter.

  Moreover, as shown in FIG.3 (b), in other examples 2 of a diameter reduction prevention part, a diameter reduction prevention part is not the annular recessed part 18a (refer FIG. 2) provided in the coupling main body 11 mentioned above, An annular recess 18 c provided in the nut 13 is used. The annular recess 18c is formed in the axial direction of the collet 12 in the same manner as the annular recess 18a provided in the joint body 11 at the place where the tapered portion 13b (see FIG. 3A) of the nut 13 is formed. This end is provided so as to face the end face, so that the annular axial end portion of the collet 12 (here, the protruding end side of the core member 14) can enter (see FIG. 3B). It is formed corresponding to the portion and functions as a locking portion for locking the collet 12. In this case, an inclined surface 11e is formed on the joint body 11 so that the tapered portion 12b of the collet 12 on the side of the rotating action portion 11a comes into contact with each other and comes into sliding contact with each other.

  Moreover, as shown in FIG.3 (c), in the other examples 3 of a diameter reduction prevention part, a diameter reduction prevention part is an annular convex provided in the joint main body 11 of the other example 1 of a diameter reduction prevention part. The ring 18b (not FIG. 3A) is an annular protrusion 18d provided on the nut 13. The annular protrusion 18d is formed by a tapered portion 13b of the nut 13 (see FIG. 3A). Similar to the annular ridge 18b provided on the joint body 11, it is provided opposite to the end face in the axial direction of the collet 12, and the groove-like recess 12e of the collet 12 can enter. It is formed corresponding to this groove-like recess 12e.

  The groove-like recess 12e of the collet 12 is provided in an annular shape centering on the collet axis over the entire circumference of the end faces on both sides in the axial direction of the collet 12 (see FIG. 3C). By entering and locking in the groove-like recess 12e, it functions as a diameter reduction preventing portion. Also in this case, an inclined surface 11e is formed on the joint body 11 so that the tapered portion 12b of the collet 12 on the rotating action portion 11a side comes into contact with each other and comes into sliding contact with each other.

As in the example shown in FIGS. 3B and 3C, in the configuration in which the diameter reduction preventing portion is formed on the nut 13, the inclined surface 11e of the joint body 11 and the tapered portion 12b of the collet 12 are in contact with each other. As the nut 13 is tightened, the tapered portion 12c side of the collet 12 is fixed, and only the tapered portion 12b side of the collet 12 is pushed toward the pipe P side on the entire circumferential surface and narrowed down. And the diameter is reduced.
Each of the above-mentioned diameter reduction preventing portions (annular recess 18a, annular ridge 18b, annular recess 18c, and annular ridge 18d) locks the collet 12 formed on the joint body 11 or the nut 13. It functions as a locking part.

As shown in FIGS. 1, 2 (a), (b), a recess is formed on the outer peripheral surface of the core member 14 of the present embodiment at a position corresponding to the position where the collet 12 is crimped to the pipe P when the collet 12 is reduced in diameter. 19 is provided.
In the present embodiment, the concave portion 19 is formed by the convex strip portion 12d that is formed on the inner peripheral surface of the collet 12 and protrudes toward the pipe P side, and the nut 13 attached to the joint body 11 is tightened and the collet 12 is contracted. It is formed at the position of the inner surface of the pipe P corresponding to the biting position when the diameter of the pipe P penetrates the entire outer periphery of the pipe P that penetrates the collet 12 (see FIG. 2B). By providing the recess 19, the pipe P can be securely clamped and fixed when the collet 12 has a reduced diameter. In addition, the position where the recessed part 19 is provided may overlap with the position (refer FIG. 2 (a), (b)) to which the O ring 15 for the water stop of the core material 14 was mounted | worn.

In this embodiment, each convex strip 12d of the collet 12, which is a portion where the collet 12 is crimped to the pipe P when the collet 12 is reduced in diameter, is formed with a sharp tip. Since the tip of each protruding line portion 12d is formed to be sharp, when the collet 12 is crimped to the pipe P when the collet 12 is reduced in diameter, each protruding line portion 12d is surely attached to the entire outer peripheral surface of the pipe P. It can be bitten (see FIG. 2B). Therefore, when the collet 12 is reduced in diameter, the pipe P passing through the collet 12 is tightened between the collet 12 and the core material 14 with a reduced diameter of the collet 12, that is, with less nut 13. The pipe P can be securely fixed by the amount.
The diameter reduction preventing portion is not limited to the above-described example. When the nut 13 is tightened, the diameter of the collet 12 is prevented while the diameter of the collet 12 is reduced on the one side in the axial direction as the nut 13 is tightened. It is sufficient if only the other side in the direction can be reduced in diameter.

Further, the taper portions 12b and 12c of the collet 12, the taper portion 13b of the nut 13, and the inclined surface 11c of the joint main body 11 have the same taper angle and inclined angle between the surfaces that come into contact with each other and are in sliding contact with each other. They may be different, and further, one may be constituted by a tapered surface and an inclined surface, and the other may be constituted by a corner portion (for example, a corner portion of a cube) that is not a tapered surface or an inclined surface.
Further, the taper angle and the inclination angle between the surfaces of the tapered portions 12b and 12c of the collet 12, the tapered portion 13b of the nut 13 and the inclined surface 11c of the joint body 11 which are in contact with each other and are in sliding contact with each other are relative to the axial direction. For example, the angle of the nut 13 and the joint body 11 may be larger, and in this case, the nut 13 can be tightened with a smaller tightening amount.

  10: Pipe joint, 11: Joint body, 11a: Rotating action part, 11b: Male thread part, 11c: Inclined surface, 12: Collet, 12a: Center part, 12b, 12c: Tapered part, 12d: Convex part, 12e: groove-shaped recess, 13: nut, 13a: female screw part, 13b: taper part, 13c: rotating action part, 14: core material, 15: O-ring, 16: pipe socket, 17: notch, 18a: 18c: annular recess (diameter prevention portion), 18c: annular ridge (diameter prevention portion), 18b: annular ridge (diameter prevention portion), 18c Concave part, P: pipe, d: gap space, s: nut tightening amount.

Claims (5)

By tightening a nut screwed onto the outer peripheral surface of the joint body, an annular collet disposed inside the nut is reduced in diameter, and the pipe is tightened to hold the pipe. ,
The collet is a collet whose diameter on both sides in the axial direction is reduced when tightened,
A pipe joint characterized in that a diameter reduction preventing portion is provided for preventing a diameter reduction operation on one side of the collet in the collet axial direction when the nut is tightened.   2. The pipe joint according to claim 1, wherein the collet is formed in a symmetric shape in which both sides of the collet axis direction are symmetric with respect to the center of the collet axis direction.   3. The pipe joint according to claim 1, wherein the diameter reduction preventing portion is a locking portion that is formed on the joint main body or the nut and locks the collet. The joint body includes a core member into which the pipe is inserted on the outer peripheral side,
The pipe according to any one of claims 1 to 3, wherein a concave portion is provided at a position corresponding to a position where the collet is crimped to the pipe when the collet has a reduced diameter on the outer peripheral surface of the core member. Fittings.   The pipe joint according to any one of claims 1 to 4, wherein a tip of the part where the collet is crimped to the pipe when the collet is reduced in diameter is sharp.

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