JP2017036757A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of excessive internal stress in screwing of a male screw member.SOLUTION: A pipe joint 10 includes: a cylindrical female screw member (female screw member 40) to which a cylindrical male screw member (projecting socket 20) can be screwed from one side in an axial direction; a covering member (joint body 50) made of a resin material and having a body portion 52 in which the cylindrical female screw member is embedded, and a covering portion 54 extending from an end of the body portion 52 on the one side to a radial inner side and covering an end of the cylindrical female screw member on the one side; and strain suppressing means for suppressing movement of the covering portion 54 to a radial outer side caused by pressing an end of the covering portion 54 on the one side by the male screw member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pipe joint.

  Conventionally, a pipe joint in which a metal cylinder having an internal thread is embedded in the inner surface of a synthetic resin joint has been disclosed (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 7-256697

  By the way, as a connection structure when the male screw member is screwed into the pipe joint shown in Patent Document 1, a synthetic portion sandwiched in the axial direction by a protruding portion projecting outward in the radial direction of the male screw member and a metal cylinder. Some resin materials have a structure that can be tightened in the axial direction of the pipe joint. In addition, the pipe joint is pressed from the inside due to the force of the tightened synthetic resin material moving outward in the radial direction of the pipe joint, and an excessive internal stress may be generated.

  In view of the above fact, an object of the present invention is to provide a pipe joint that suppresses generation of excessive internal stress when a male screw member is screwed together.

  The pipe joint according to the first aspect of the present invention includes a cylindrical female screw member in which a cylindrical male screw member can be screwed from one side in the axial direction, a main body portion in which the cylindrical female screw member is embedded, and the one side A covering member made of a resin material, which extends radially inward from an end portion of the main body portion and covers an end portion of the cylindrical female screw member on the one side, and the cylindrical male screw member Distortion suppressing means for suppressing movement of the covering portion toward the radially outer side by pressing an end portion of the covering portion on one side.

  According to the pipe joint of the first aspect of the present invention, the strain suppressing means suppresses the movement of the covering portion to the outside in the radial direction of the cylindrical female screw member. For this reason, it becomes difficult to press a main-body part from the radial inside. Therefore, when the cylindrical male screw member is screwed, an excessive internal stress can be prevented from being generated in the covering member.

  The pipe joint according to a second aspect of the present invention is the pipe joint according to the first aspect, wherein the strain suppression means is provided between an end surface formed at the end portion of the covering portion and the end portion of the cylindrical female screw member. The thickness of the thinnest part is less than 1 mm.

  According to the pipe joint of the second aspect of the present invention, since the thickness between the end surface of the covering portion pressed by the cylindrical male screw member and the end portion of the cylindrical female screw member is less than 1 mm, the thickness is 1 mm. Compared to the case described above, when the covering portion is pressed, the amount of strain in the axial direction is reduced. For this reason, the amount of resin that is crushed and tends to move radially outward decreases. Therefore, the force with which the main body is pressed from the inside is reduced, and the generation of excessive internal stress is suppressed.

  The pipe joint according to a third aspect of the present invention is the pipe joint according to the first aspect or the second aspect, wherein the female thread portion of the female thread member is a taper screw whose diameter increases toward the one side.

  According to the pipe joint of the third aspect of the present invention, since the female screw portion is a taper screw, when the cylindrical male screw member is strongly screwed into the cylindrical female screw member, the female screw portion expands radially outward. At this time, the main body part covering the outer periphery of the cylindrical female screw member is pressed from the radially inner side by the cylindrical female screw member.

On the other hand, since the covering portion is restrained from moving radially outward of the cylindrical female screw member by the strain suppressing means, the main body portion is hardly pressed from the radially inner side by the covering portion.
Accordingly, the generation of internal stress due to the action of both the force pressed from the radially inner side by the cylindrical female screw member and the force pressed from the radially inner side by the covering portion on the main body portion is suppressed.

  The pipe joint according to a fourth aspect of the present invention is the pipe joint according to any one of the first to third aspects, wherein the covering member is fiber reinforced.

  According to the pipe joint of the fourth aspect of the present invention, since the covering member is fiber reinforced, the strength is increased compared to the case where the fiber is not reinforced, while the toughness is reduced. That is, it is difficult to extend, and brittle fracture tends to occur if it is forced to extend.

  On the other hand, since the strain suppressing means suppresses the covering portion from moving outward in the radial direction of the female screw member, the extension of the covering portion is suppressed. Therefore, it can suppress that a coating member extends beyond the range which does not destroy.

  The pipe joint according to a fifth aspect of the present invention is the pipe joint according to any one of the first to fourth aspects, wherein an elastic material is blended in the covering member.

  According to the pipe joint of the fifth aspect of the present invention, since the covering member is blended with an elastic material, the toughness is increased as compared with the case where no elastic material is blended. The amount increases. That is, distortion tends to occur.

  On the other hand, since the amount of movement by which the covering portion moves outward in the radial direction of the female screw member is reduced by the strain suppressing means, the extension of the covering portion is suppressed. Therefore, it can suppress that a coating member extends beyond the range which does not destroy.

  According to the pipe joint according to the present invention, it is possible to suppress generation of excessive internal stress when the male screw member is screwed.

It is sectional drawing of the pipe joint which concerns on embodiment of this invention. It is a partial expanded sectional view of the pipe joint which concerns on embodiment of this invention. (A) is the elements on larger scale which show the deformation state of the pipe joint which concerns on embodiment of this invention, (B) is the elements on larger scale which show the deformation state of the pipe joint which concerns on a comparative example. It is a perspective view of the annular rib which shows the pipe joint which concerns on the modification of this invention partially fractured | ruptured along an axial direction. It is a perspective view of the radial rib which fractures | ruptures and shows the pipe joint which concerns on the modification of this invention partially along an axial direction. It is a perspective view of the internal thread member protrusion part which fractures | ruptures and shows the pipe joint which concerns on the modification of this invention partially along an axial direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a half-sectional view of a pipe joint 10 according to the first embodiment, a take-out socket 20 connected to the pipe joint 10, and a floor 30 which is a mounting portion to which the pipe joint 10 is fixed. Yes.

(Fitting)
The pipe joint 10 has a cylindrical shape, and a flow path 11 is formed therein. The pipe joint 10 is made of a metal female screw member 40 disposed on one side in the axial direction (upper side in FIG. 1, hereinafter simply referred to as one side), and a resin that surrounds the female screw member 40 from the radially outer side. And the joint main body 50.

  The axial direction is a direction along the extending direction of the pipe joint 10 formed in a cylindrical shape, and the radial direction is a direction orthogonal to the axial direction. The axial direction of the pipe joint 10, the axial direction of the female thread member 40, and the axial direction of the joint body 50 are synonymous, and the radial direction of the pipe joint 10, the radial direction of the female thread member 40, and the diameter of the joint body 50. The direction is synonymous. Hereinafter, these may be simply referred to as an axial direction and a radial direction.

On the other side in the axial direction of the pipe joint 10 (the lower side in FIG. 1, hereinafter may be simply referred to as the other side), a tubular intermediate portion 60 is extrapolated to the joint body 50.
The joint body 50 and the intermediate portion 60 may be formed of the same material or different resin materials, but in the present embodiment, the intermediate portion 60 is a transparent resin. Moreover, the main-body part 12 and the intermediate part 14 are shape | molded by two-color molding or insert molding, for example.

  Furthermore, the pipe joint 10 has a cylindrical cap 70 made of a resin material. The cap 70 is extrapolated and engaged with the distal end side of the intermediate portion 60. Between this cap 70 and the intermediate part 60, and the axial part 58 of the coupling main body 50, the annular insertion hole 12 in which the pipe body which is not shown in figure is inserted is comprised.

  Inside the cap 70, a lock ring 80 made of metal (a metal excellent in resistance to liquid (for example, stainless steel)) for holding the tube body in the insertion hole 12 is disposed. The lock ring 80 is a ring (annular body) having a substantially V-shaped cross section, and is disposed so that the substantially V-shaped opening side faces the other side (the insertion side of the pipe body) of the joint body 50. . The opening side of the lock ring 80 faces the front end portion 60A of the intermediate portion 60, and a part of the substantially V-shaped inner surface is in contact with the front end portion 60A. Further, the lock ring 80 is configured such that a claw portion 80 </ b> A at the inner peripheral side tip can bite into the outer surface of the tubular body 40.

(Female thread member)
The female thread member 40 as an example of the cylindrical female thread member of the present invention is an insert nut embedded in a joint body 50 to be described later, and has a tapered shape that is tubular and expands toward one side of the pipe joint 10. It has the internal thread part 42 which has, the end surface 44 of the one side of the pipe joint 10, the outer peripheral surface 46 with a constant diameter, and the end surface 48 of the other side of the pipe joint 10. A chamfer 44 </ b> A is formed at the radially inner end of the end surface 44, which is a 45 ° chamfer. Similarly, a chamfer 44B is also formed at the radially outer end of the end surface 44, which is a 45 ° chamfer. An annular groove 46A having a groove bottom parallel to the outer peripheral surface 46 is formed on the outer peripheral surface 46, and is engaged with an annular protrusion 52B of the joint body 50 described later.

  The external diameter of the female screw member 40 is about 25 mm for D1, and the length L1 along the axial direction is about 17 mm. The female thread portion 42 is a pipe taper female thread having a nominal diameter of 1/2 inch (so-called Rc thread), and an effective thread length L2 along the axial direction is about 13 mm. The groove width L3 of the annular groove 46A is about 1.5 mm, the depth D3 is about 1 mm, and the length L4 along the axial direction from the groove wall on the end face 44 side to the end face 44 of the annular groove 46A is about 5 mm. ing. Further, a knurling process is applied to the portion of the outer peripheral surface 46 from the groove wall on the end face 44 side of the annular groove 46A to the end face 44, and when the joint body 50 is formed, the resin material enters the mesh and is joined. Strength is increased.

  The above dimensions include a range of about plus or minus 0.1 mm in consideration of manufacturing errors. Moreover, although it is set as the said dimension in this embodiment, embodiment of this invention is not restricted to this, A various dimension can be taken. The same applies to the dimensions described below. Further, the female screw member 40 is not limited to metal and may be made of high-strength resin. Further, in this embodiment, the female screw member 40 is a pipe taper female screw, but the embodiment of the present invention is not limited to this, and may be a pipe parallel screw.

(Fitting body)
The joint main body 50 as an example of the covering member of the present invention has a cylindrical shape, a main body portion 52 in which the female screw member 40 is embedded, and a covering portion 54 that extends radially inward from one end of the main body portion 52. And a flange 56 extending radially outward from the end on one side of the main body 52, that is, on the opposite side of the covering 54, and the other side in the axial direction of the pipe joint 10 (the lower side in FIG. And a shaft portion 58 disposed on the other side.

  In addition, as a resin material for forming the joint body 50, from the viewpoint of mechanical strength, engineering plastics such as polyphenylene sulfide (PPS), polyacetal (POM), polyamide (PA), polycarbonate (PC), polyethylene terephthalate (PET), etc. Alternatively, it is preferable to use a fiber reinforced resin such as glass fiber reinforced resin (GFRP) or carbon fiber reinforced resin (CFRP). In addition, conventionally well-known resin can be used as a matrix resin (base material) of fiber reinforced resin.

  52 A of inner peripheral surfaces of the main-body part 52 contact | abut with the outer peripheral surface 46 of the internal thread member 40, and have coat | covered the external peripheral surface 46 of the internal thread member 40. FIG. Further, the annular protrusion 52B formed on the inner peripheral surface 52A and projecting radially inward is engaged with the annular groove 46A of the female screw member 40, so that the female screw member 40 and the joint body 50 are relatively moved in the axial direction. To suppress. That is, the main body portion 52 functions as a holding portion that holds the female screw member 40. As described above, the covering portion 54 and the flange portion 56 are formed at one end portion of the main body portion 52, and the reduced diameter portion 52C extending radially inward is formed at the other end portion. Yes. The reduced diameter portion 52C is connected to one end portion of a shaft portion 58 to be described later, and the inner side surface 52D of the reduced diameter portion 52C is in contact with the end surface 48 of the female screw member 40.

  The outer diameter D4 of the main body portion 52 in the outer peripheral portion of the female screw member 40 is about 31 mm. As described above, the outer diameter D1 of the female screw member 40 is about 25 mm, and thus the thickness D5 of the main body portion 52 is about 3 mm. It has become. Further, the diameter-reduced portion 52C is connected to the shaft portion 58 while being gently inclined at an angle of about 60 ° with respect to the radial direction.

  The flange portion 56 is integrally formed with the main body portion 52, and is a protruding portion that protrudes from the main body portion 52 in a plate shape (in the present embodiment, a disc shape) toward the outside in the radial direction. The flange portion 56 is formed with a plurality of (three in this embodiment) through-holes 56A for attaching the flange portion 56 to the floor surface 30A of the floor 30 using a stopper (not shown). These through holes 56 </ b> A are formed at intervals so that the center angles are equal in the circumferential direction from the center of the flange portion 56. The through hole 56A is tapered at the opening in order to use a countersunk screw as a fastener.

  The thickness L5 of the flange portion 56 is about 4 mm, and the outer diameter D5 of the flange portion is about 58 mm. The diameter D6 of the circumference passing through the center of the through hole 56A is about 46 mm, the hole diameter D7 of the through hole 56A is about 4.5 mm, the taper angle is about 45 °, and the depth L7 is about 1.5 mm. ing.

  The shaft portion 58 is integrally formed with the main body portion 52, has an outer diameter smaller than the outer diameter of the main body portion 52, and has an inner diameter smaller than the inner diameter of the female screw member 40. Two circumferential grooves 58 </ b> A are formed on the outer peripheral surface of the shaft portion 58. An annular water stop ring 90 is fitted into these circumferential grooves 58 </ b> A and is connected to the other axial side of the pipe joint 10. The body and the pipe joint 10 are water-stopped.

  As shown in FIG. 2, the covering portion 54 is a thin resin portion that is integrally formed with the main body portion 52 and has a plate shape thinner than the flange portion 56. The covering portion 54 covers the radially outer side of the end face 44 of the female screw member 40, and the thickness dimension of the covering portion 54 is the width dimension (from the radially inner end of the covering portion 54) that the covering portion 54 covers the end face 44. (Diameter dimension in the radial direction to the outer periphery of the female screw member 40). The thickness of the thinnest part between the end surface 54A of the covering portion 54 and the end surface 44 of the female screw member 40 is less than 1 mm.

  An end face 54A on the one side in the axial direction of the pipe joint 10 of the covering portion 54 is an extension of the take-out socket 20 in a state where the take-out socket 20 which is an example of the cylindrical male screw member in the present invention is connected to the pipe joint 10. It is in contact with the end face 22A of the portion 22. In this embodiment, the outer diameter of the protruding portion 22 of the take-out socket 20 is larger than the outer diameter of the female screw member 40, and the male screw portion 24 of the take-out socket 20 is replaced with the female screw portion 42 of the female screw member 40. When screwed and tightened, the entire portion of the covering portion 54 that overlaps the female screw member 40 in the axial direction is pressed.

  Since the diameter D8 on the radially inner side of the covering portion 54 is about 23 mm, and the outer diameter D1 of the female screw member 40 is about 25 mm as described above, the covering portion 54 defines the end surface 44 of the female screw member 40 as follows. Cover about 1 mm from the outside in the radial direction. Further, the thickness L8 of the covering portion 54 is set to 0.5 mm.

(Function and effect)
Next, the operation and effect of the pipe joint 10 of the present embodiment will be described with reference to FIG. FIG. 3A shows a state where the take-out socket 20 is attached to the pipe joint 10 according to the present embodiment, and FIG. 3B shows the state where the take-out socket 20 is attached to the pipe joint 100 according to the comparative example. The installed state is shown.

  As shown in FIG. 3A, when the male threaded portion 24 of the take-out socket 20 is screwed into the female threaded portion 42 of the female threaded member 40 in the pipe joint 10 of the present embodiment and tightened, the thickness is set to t. The end surface 54 </ b> A of the covering portion 54 is pressed by the end surface 22 </ b> A of the overhang portion 22 of the carry-out socket 20. At this time, the covering portion 54 is deformed by Δt in the axial direction, and the thickness of the covering portion 54 is (t−Δt). Further, when the width of the end face 54A pressed by the end face 22A is a pressing width s, the resin material in the portion indicated by the area of about (s × Δt) is on the radially outer side and the other side in the axial direction of the pipe joint 10. Move towards.

  On the other hand, as shown in FIG. 3B, when the male threaded portion 24 of the take-out socket 20 is screwed into the female threaded portion 420 of the female threaded member 400 in the pipe joint 100 of the comparative example, the thickness is set to d. The end surface 540 </ b> A of the covering portion 540 is pressed by the end surface 22 </ b> A of the overhang portion 22 of the carry-out socket 20. At this time, the covering portion 540 is deformed by Δd in the axial direction, and the thickness of the covering portion 540 is (d−Δd). Also, assuming that the width of the end surface 540A pressed by the end surface 22A is the pressing width s, the resin material in the portion indicated by the area of about (s × Δd) is on the radially outer side and the other side in the axial direction of the pipe joint 10. Move towards.

  Here, in this embodiment, t (L8 in FIG. 2) is about 0.5 mm, and d is about 3 mm in the comparative example. When the take-out socket 20 is screwed with the same tightening force, the deformation amount per unit thickness is equal, so Δd is a value that is six times Δt. For example, when Δt is 0.1 mm, the deformation amount per unit thickness (1 mm) is 0.2 mm, and Δd is 0.6 mm. That is, in this embodiment, the volume of the resin material that moves toward the radially outer side and the other side in the axial direction of the pipe joint 10 is about 1/6 of the comparative example.

  Thus, in the present embodiment, the thickness between the end surface 54A of the covering portion 54 pressed by the take-out socket 20 and the end surface 44 of the female screw member 40, that is, the thickness of the covering portion 54 is less than 1 mm. Compared with the case where it is 1 mm or more, when the coating | coated part 54 is pressed, the distortion amount of an axial direction becomes small. For this reason, the amount of resin that is crushed and moves radially outward decreases. In other words, the thickness of the covering portion 54 being less than 1 mm is a distortion suppressing means for suppressing the covering portion 54 from moving toward the radially outer side and the other side in the axial direction of the pipe joint 10. . Therefore, the force with which the main body is pressed from the inside is reduced, and the generation of internal stress is suppressed.

  For this reason, even if the take-out socket 20 is tightened with a strong torque, the joint body 50 is suppressed from breaking. More specifically, when the takeout socket 20 is tightened with a strong torque, before the joint body 50 is broken, the gap between the overhanging portion 22 and the male screw portion 24 of the takeout socket 20 is sheared. That is, in this embodiment, the breaking strength of the joint body 50 is made stronger than that of the take-out socket 20 by making the thickness of the covering portion 54 less than 1 mm.

  For example, the excessive tool torque assumed when connecting the joint of the present embodiment is assumed to have an upper limit of 60 Nm, but when the thickness of the covering portion 54 is 1 mm, the joint body 50 breaks at 60 Nm. On the other hand, for example, if it is 0.5 mm, it will be destroyed with a torque exceeding 65 Nm exceeding 60 Nm.

(Other embodiments)
The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

  For example, as shown in FIG. 4, an annular rib 54 </ b> B as a strain suppressing means may be erected on one side in the axial direction of the pipe joint 10 from the end face 54 </ b> A at the radially inner end of the covering portion 54. By providing the annular rib 54B, when the takeout socket 20 is screwed into the female screw member 40, the end surface 22A of the takeout socket 20 first presses the annular rib 54B, and the screwing force increases. In the case where the annular rib 54B falls to the outside in the radial direction, the covering portion 54 is suppressed from being distorted in the axial direction.

  For example, as shown in FIG. 5, radial ribs 54 </ b> C serving as strain suppressing means extending radially outward from the radially inner end portion of the covering portion 54 are spaced apart in the circumferential direction on the end surface 54 </ b> A of the covering portion 54. It may be arranged open. By providing the radial ribs 54C, when the takeout socket 20 is screwed into the female screw member 40, the end surface 22A of the takeout socket 20 first presses the radial ribs 54C and the screwing force increases. The radial ribs 54 </ b> C are inclined in the circumferential direction, so that the covering portion 54 is prevented from being distorted in the axial direction.

  For example, as shown in FIG. 6, an annular rib 44 </ b> C as a strain suppressing means may be erected from the end face 44 of the female screw member 40 to one side in the axial direction of the pipe joint 10. At this time, the height of the annular rib 44 </ b> C is formed to be the same as the thickness of the covering portion 54 or higher than the thickness of the covering portion 54. By providing the annular rib 44C, when the takeout socket 20 is screwed into the female screw member 40, the end surface 22A of the takeout socket 20 presses the annular rib 54C, and the covering portion 54 is pressed by the end surface 22A. Therefore, the covering portion 54 is suppressed from being distorted in the axial direction.

  For example, when an annular rib as a strain suppressing means is protruded from the end face 22A of the take-out socket 20 and the take-out socket 20 is screwed into the female screw member 40, the annular rib contacts the end face 44 of the female screw member 40. You may make it contact. At this time, the height of the annular rib provided on the end face 22 </ b> A is formed to be equal to or higher than the thickness of the covering portion 54. Thereby, when the take-out socket 20 is screwed into the female screw member 40, the annular rib presses the end surface 44 of the female screw member 40, and the covering portion 54 is suppressed from being pressed against the end surface 22A. The covering portion 54 is suppressed from being distorted in the axial direction. Alternatively, the covering portion 54 is not pressed against the end face 22A by making the outer diameter of the overhanging portion 22 of the carry-out socket 20 smaller than the diameter of the radially inner end portion of the covering portion 54. Is obtained.

  For example, a slit may be formed in the flange portion 56 from the through hole 56A toward the inside in the radial direction. Further, a slit may be formed separately from the through hole 56A. If it does in this way, the internal stress which generate | occur | produces when it is pressed by the taking-out socket 20 and the coating | coated part 54 will move to radial direction outer side can be absorbed in a slit part.

  For example, as the resin material for forming the joint body 50, a material in which an elastic material is blended can be used. By blending the elastic material, the toughness of the joint body 50 is increased and the internal stress is relieved. Thereby, after tightening the take-out socket 20 with an excessive torque, after a predetermined time (for example, one week) has elapsed, it is possible to suppress the occurrence of fatigue failure in which the main body portion 52 and the flange portion 56 are destroyed. .

  In order to suppress the occurrence of fatigue fracture, for example, in a test method according to the evaluation method defined in ISO527-1 and ISO527-2, the tensile elongation at break of the resin material (until the test piece is broken until breakage occurs) The elongation of the test piece when it is pulled in one direction and breaks (for example, it becomes 2.0% when a 100 mm test piece breaks at 102 mm). It is valid.

  As a specific embodiment, resin material A containing 65% polyphenylene sulfide (PPS) as a base material, 30% reinforcing fiber (GF) as a reinforcing material, and 5% polyethylene-based elastomer (EL) as an elastic material is used. When pulled by the above test method, the tensile elongation at break was 2.4%, and no fatigue failure occurred after the lapse of a predetermined time (168 hours).

  As a comparative example for this, the elongation rate when a resin material B containing 60% PPS, 40% GF, and not containing EL was pulled by the same test method was 1.8%, and the predetermined time (24 hours) Fatigue fracture occurred before lapse of time. Further, the elongation rate when the resin material C containing 70% PPS, 30% GF, and not containing EL was pulled by the same test method was 2.0%, and before the predetermined time (48 hours) elapsed Fatigue failure occurred.

  In this embodiment, the base material, the reinforcing material, and the elastic material included in the resin material are each composed of PPS, GF, and EL, but the embodiment of the present invention is not limited to this, and the tensile elongation at break is 2 If it exceeds 0.0%, the same effect can be obtained.

  Further, when the joint body is used for water supply / hot water supply, long-term durability can be ensured by setting the tensile elongation at break of the resin material to 5% or less. Specifically, it is possible to suppress creep rupture within a predetermined time (for example, 20 years) from the start of use.

  As a specific embodiment, in the above-described resin material A, in the hot internal pressure creep test defined in JISK6729, no creep failure occurred at the time when a predetermined time (165 hours) had elapsed. As a comparative example, the elongation rate when a resin material D containing 60% PPS, 30% GF, and 10% EL is pulled by the same test method is 1.8%, and the same hot internal pressure is obtained. In the creep test, creep rupture occurred before a predetermined time (165 hours) elapsed.

10 Pipe joint 20 Take-out socket (cylindrical male screw member)
40 Female thread member (tubular female thread member)
42 Female thread 44 End face (end)
50 Joint body (covering member)
52 Body 54 Cover 54A End Face 54B Annular Rib (Distortion Suppression Unit)
54C Radial rib

Claims (5)

A cylindrical female screw member in which the cylindrical male screw member can be screwed from one side in the axial direction;
A main body portion in which the cylindrical female screw member is embedded, and a covering portion extending radially inward from an end portion of the main body portion on the one side and covering an end portion of the cylindrical female screw member on the one side. A covering member made of a resin material,
Distortion suppressing means for suppressing movement of the covering portion to the outside in the radial direction due to the cylindrical male screw member pressing an end portion of the covering portion on the one side;
With pipe fittings.   The said distortion suppression means is comprised by the thickness of the thinnest part between the end surface formed in the said edge part of the said coating | coated part and the said edge part of the said cylindrical internal thread member being less than 1 mm, It is comprised. The pipe joint according to 1.   The pipe joint according to claim 1 or 2, wherein the female screw portion of the cylindrical female screw member is a taper screw whose diameter increases toward the one side.   The pipe joint according to any one of claims 1 to 3, wherein the covering member is fiber reinforced.   The pipe joint according to any one of claims 1 to 4, wherein an elastic material is blended in the covering member.