Dissimilar pipe bonded joint and pipe structure

Abstract

To provide a dissimilar pipe bonded joint which enables adjustment of a fastening amount of a metal pipe fitted in a metal joint part.SOLUTION: A dissimilar pipe bonded joint 20 includes: a metal joint part 21 having a metal connection part 22 in which a joint screw 22b is formed on a joint installation surface 22a, which is its inner peripheral surface or outer peripheral surface, and a joint engagement part 24 which may project from the joint installation surface or be retracted in a radial direction relative to the metal connection part and is biased so as to protrude in the radial direction; and a resin joint part 36 having a resin connection part 37 and connected to the metal joint part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a dissimilar pipe joint and a piping structure. [Background technology]

[0002] Conventionally, dissimilar pipe joints have been used to connect metal pipes and plastic pipes (see, for example, Patent Documents 1 and 2). The dissimilar pipe joints include a metal connection part having a joint thread that fits with the metal pipe, and a plastic joint part having a plastic connection part that is connected to the plastic pipe. The metal pipe is connected to the metal connection portion of the dissimilar pipe joint by fitting the joint threads of the metal connection portion and the pipe threads of the metal pipe into each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-066328 A [Patent Document 2] JP 2009-250408 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when connecting a metal pipe to a metal connection part of a dissimilar pipe joint, if the metal pipe is tightened too much, the threads that fit together may be deformed, whereas if the metal pipe is not tightened enough, the fluid flowing through the dissimilar pipe joint may leak from the connection part between the metal connection part and the metal pipe to the outside of the dissimilar pipe joint.

[0005] The present invention has been made in consideration of such problems, and has an object to provide a dissimilar pipe joint and a piping structure that enable adjustment of the amount of tightening of a metal pipe fitted into a metal connection portion. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention proposes the following means. (1) Aspect 1 of the present invention is a dissimilar pipe joint comprising: a metal joint part having a metal connection part having a joint thread formed on a joint installation surface, which is an inner or outer circumferential surface of the metal joint part, and a joint locking part that is capable of protruding and retracting radially from the joint installation surface relative to the metal connection part and is biased to protrude in the radial direction; and a resin joint part having a resin connection part and connected to the metal joint part.

[0007] In this invention, the metal pipe can be connected to the metal joint by, for example, fitting the pipe thread of the metal pipe into the joint thread of the metal joint part of the metal joint part. At this time, by radially inserting the joint locking part into the metal joint part against the biasing force, the joint locking part does not interfere with the connection between the metal joint part and the metal pipe. For example, a joint locking portion that protrudes radially from the metal connection portion engages with a peripheral portion of a pipe opening of the metal pipe, thereby preventing the metal pipe from moving in the axial direction of the metal connection portion relative to the metal connection portion. Therefore, the amount of tightening of the metal pipe fitted into the metal connection portion can be adjusted.

[0008] (2) A second aspect of the present invention may be a dissimilar pipe joint as described in (1), in which the joint locking portion is disposed at an end portion of the metal connection portion that is closer to the resin joint portion than the metal joint portion. In this invention, for example, the axial length of the portion where the joint thread and the pipe thread are fitted together is longer on the metal joint part side relative to the resin joint part than the joint locking part, so that it is possible to more reliably prevent the fluid flowing through the dissimilar pipe joint from leaking out of the dissimilar pipe joint through between the joint thread and the pipe thread.

[0009] (3) A third aspect of the present invention may be the dissimilar pipe joint according to (1) or (2), in which the joint installation surface is the inner circumferential surface of the metal connection portion. In this invention, the joint locking portion protrudes radially inward relative to the metal connection portion, and does not protrude radially outward relative to the metal connection portion, thereby preventing the joint locking portion from interfering with handling of the dissimilar pipe joint alone.

[0010] (4) A fourth aspect of the present invention is a piping structure comprising the dissimilar pipe joint joint according to any one of (1) to (3) and a metal pipe that fits into the dissimilar pipe joint, wherein the metal pipe has a pipe thread formed on its pipe installation surface facing the joint installation surface to fit into the joint thread, and a metal pipe body having a pipe opening formed on the pipe installation surface, the pipe opening having a peripheral portion that engages with the joint locking portion.

[0011] In this invention, the metal pipe can be connected to the metal joint by fitting the pipe thread of the metal pipe body of the metal pipe into the joint thread of the metal joint part of the metal joint part. At this time, by radially inserting the joint locking part into the metal joint part against the biasing force, the joint locking part does not interfere with the connection between the metal joint part and the metal pipe. The joint locking portion protruding radially from the metal connection portion engages with the peripheral edge of the pipe opening in the metal pipe body, preventing the metal pipe body from moving in the axial direction of the metal connection portion relative to the metal connection portion. Therefore, the amount of tightening of the metal pipe fitted into the metal connection portion can be adjusted.

[0012] (5) A fifth aspect of the present invention is a piping structure comprising a dissimilar pipe joint joint and a metal pipe which fits into the dissimilar pipe joint joint, wherein the dissimilar pipe joint has a metal joint part having a metal connection part with a joint installation surface, which is an inner or outer circumferential surface of the dissimilar pipe joint, and a joint opening part formed on the joint installation surface, and a resin joint part having a resin connection part and connected to the metal joint part, and the metal pipe has a metal pipe main body, on its pipe installation surface opposite the joint installation surface, and a pipe locking part which is radially protrudible and retractable relative to the metal pipe main body and is biased to protrude in the radial direction, and which engages with a peripheral part of the joint opening part in the metal connection part.

[0013] In this invention, the metal pipe can be connected to the metal joint by fitting the pipe thread of the metal pipe body of the metal pipe into the joint thread of the metal joint part of the metal joint part. At this time, by radially inserting the pipe locking part into the metal pipe body against the biasing force, the pipe locking part does not interfere with the connection between the metal joint part and the metal pipe. The metal pipe is prevented from moving in the axial direction of the metal connection part relative to the metal pipe body by engaging the pipe locking part, which protrudes radially from the metal pipe body, with the peripheral portion of the joint opening of the metal connection part. For example, the resin connection part is connected to the resin pipe. Therefore, the amount of tightening of the metal pipe fitted into the metal connection portion can be adjusted. Effect of the Invention

[0014] In the dissimilar pipe joint and piping structure of the present invention, the tightening amount of the metal pipe fitted into the metal connection portion can be adjusted. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view of a main part of a piping structure according to a first embodiment of the present invention. [Diagram 2] 4 is a cross-sectional view of a main part of the piping structure as viewed from the side. FIG. [Diagram 3]FIG. 4 is a cross-sectional view illustrating a process of fitting a metal pipe into a dissimilar pipe joint. [Figure 4] FIG. 4 is a cross-sectional view illustrating a procedure for constructing a homogeneous and heterogeneous pipe joint. [Diagram 5] FIG. 4 is a cross-sectional view illustrating a procedure for constructing a homogeneous and heterogeneous pipe joint. [Figure 6] FIG. 11 is a cross-sectional view of a main part of a piping structure according to a second modified example of the first embodiment of the present invention. [Figure 7] FIG. 5 is a cross-sectional view of a main part of a piping structure according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (First embodiment) Hereinafter, a first embodiment of a dissimilar pipe joint and a piping structure according to the present invention will be described with reference to Figs. 1 to 6. As shown in Figs. 1 and 2, a piping structure 1 of this embodiment includes a metal pipe 10, a dissimilar pipe joint 20 of this embodiment, and a resin pipe (not shown). Here, the metal pipe 10 and the plastic pipe are each formed in a tubular shape, and the dissimilar pipe joint 20 is formed in a cylindrical shape. The central axes (axial lines) of the metal pipe 10, the dissimilar pipe joint 20, and the plastic pipe are arranged coaxially with a common axis. Hereinafter, the common axis is referred to as the axis O1, and the direction along the axis O1 is referred to as the axis O1 direction.

[0017] In the direction of the axis O1, the side of the resin joint portion 36 relative to the metal joint portion 21 described below of the dissimilar pipe joint 20 is referred to as a first side D1. The side of the metal joint portion 21 relative to the resin joint portion 36 is referred to as a second side D2. A direction perpendicular to the axis O1 is called a radial direction, and a direction going around the axis O1 is called a circumferential direction.

[0018] The metal pipe 10 has a metal pipe main body 11. As shown in FIG. 2, a pipe thread 11b, which is a male thread, is formed on a pipe installation surface 11a, which is the outer circumferential surface of the metal pipe main body 11. The pipe thread 11b is formed on an end of the first side D1 of the metal pipe main body 11. A pipe through hole (pipe opening) 11c is formed in the range of the pipe installation surface 11a where the pipe thread 11b is formed in the direction of the axis O1. The pipe through hole 11c penetrates the peripheral wall of the metal pipe main body 11 in the radial direction. The pipe through hole 11c is formed in a part of the metal pipe main body 11 in the circumferential direction. For example, the pipe through hole 11c is cylindrical with an axis along the radial direction. The metal pipe body 11 is made of gunmetal, stainless steel or the like.

[0019] 1 and 2, a metal pipe 10 is fitted into a dissimilar pipe joint 20. The dissimilar pipe joint 20 has a metal joint portion 21, a sealing member 31, a resin joint portion 36, and a cap nut 41. The metal joint portion 21 has a metal connection portion 22, a biasing member 23, a joint locking portion 24, a connection portion 25, and a tubular portion 26. The metal connection part 22 and the tubular part 26 are formed in a tubular shape and are disposed on the axis O1. As shown in Fig. 2, a joint installation surface 22a, which is the inner peripheral surface of the metal connection part 22, is formed with a joint thread 22b, which is a female thread. The pipe installation surface 11a of the metal pipe main body 11 faces the joint installation surface 22a. Here, "A and B face each other" means that A and B face each other in a contact or spaced-apart state.

[0020] A recess 22c is formed at an end of the first side D1 on the joint installation surface 22a of the metal connection part 22. The recess 22c is formed in a part of the circumferential direction of the metal connection part 22. For example, the recess 22c is cylindrical with an axis along the radial direction. The pipe thread 11 b of the metal pipe body 11 is fitted into the joint thread 22 b of the metal connection portion 22 .

[0021] For example, the biasing member 23 is a helical spring. The biasing member 23 is disposed in the recess 22c of the metal connection portion 22. A radially outer end of the biasing member 23 is fixed to the bottom surface of the recess 22c. For example, the joint locking portion 24 is cylindrical with an axis along the radial direction. It is preferable that a surface 24a of the joint locking portion 24 facing the second side D2 is gradually inclined toward the first side D1 as it moves radially inward.

[0022] The joint locking portion 24 is disposed radially inward from the biasing member 23. A radially inner end portion of the biasing member 23 is fixed to the joint locking portion 24. When the biasing member 23 contracts radially, the joint locking portion 24 can be accommodated in the recess 22c of the metal connection portion 22. At this time, the joint locking portion 24 is biased so as to protrude radially inward relative to the metal connection portion 22. The joint locking portion 24 is disposed at an end portion of the metal connection portion 22 on the first side D1. That is, the joint locking portion 24 can protrude and retract radially inward from the joint installation surface 22 a relative to the metal connection portion 22 . The peripheral edge of the pipe through hole 11c in the metal pipe main body 11 engages with a joint locking portion 24 protruding radially inward in the axial direction O1 and the circumferential direction.

[0023] The connection part 25 is formed in an annular shape and is disposed coaxially with the axis O1. The connection part 25 protrudes radially outward and radially inward from an end of the first side D1 of the metal connection part 22. The inner diameter of the connection part 25 is smaller than the inner diameter of the metal connection part 22. 2, a groove 25b is formed on a surface 25a facing the first side D1 of the portion protruding radially inward in the connecting portion 25. The groove 25b is formed over the entire circumference around the axis O1.

[0024] The cylindrical portion 26 extends from a radially outer end of the connection portion 25 toward the first side D1. As shown in Fig. 1, for example, the outer shape of the cylindrical portion 26 is a hexagonal polygon. Note that the outer shape of the cylindrical portion 26 is not limited to a hexagonal polygon, and may be a dodecagonal polygon, etc. As shown in FIGS. 1 and 2, the tubular portion 26 is coaxially connected to the metal connection portion 22 on the first side D1 with respect to the metal connection portion 22. As shown in Fig. 2, a female thread 26a is formed on the inner peripheral surface of the cylindrical portion 26. The inner diameter of the cylindrical portion 26 is larger than the inner diameter of the metal connection portion 22 and the inner diameter of the connection portion 25. The outer diameter of the cylindrical portion 26 is larger than the outer diameter of the metal connection portion 22. A cylindrical portion through hole 26b is formed in a portion of the cylindrical portion 26 on the first side D1. The cylindrical portion through hole 26b penetrates the peripheral wall of the cylindrical portion 26 in the radial direction. The cylindrical portion through hole 26b is formed only in a portion of the cylindrical portion 26 in the circumferential direction.

[0025] The metal connection portion 22, the connection portion 25, and the tubular portion 26 of the metal joint portion 21 are integrally formed of the same material as the metal pipe body 11. The joint locking portion 24 is also formed of the same material as the metal pipe body 11.

[0026] For example, the sealing member 31 is an O-ring. The sealing member 31 is disposed in the groove 25b of the connection portion 25. In a natural state in which no external force is applied to the sealing member 31, the sealing member 31 protrudes beyond the surface 25a of the connection portion 25 toward the first side D1. The sealing member 31 is formed of EPDM (ethylene propylene diene rubber) or the like, which has excellent resistance to aging, weather, ozone, and oil.

[0027] The resin joint portion is connected to the metal joint portion 21. The resin joint portion has a resin connection portion 37 and a flange portion . The resin connection part 37 is formed in a cylindrical shape. The resin connection part 37 is disposed coaxially with the axis O1. An end part 37a of the resin connection part 37 on the second side D2 is disposed inside the cylindrical part 26. An end part of the resin connection part 37 on the first side D1 protrudes toward the first side D1 beyond the cylindrical part 26. The flange 38 is formed in an annular shape and is disposed coaxially with the axis O1. The flange 38 protrudes radially outward from the end 37a of the resin connection portion 37. An end face of the second side D2 of the resin connection portion 37 and an end face of the second side D2 of the flange 38 are flush with each other. These end faces contact the surface 25a of the connection portion 25 from the first side D1 of the surface 25a. At this time, the sealing member 31 in its natural state is deformed so as to be elastically crushed in the direction of the axis O1. The flange portion 38 is disposed inside the cylindrical portion 26. The flange portion 38 is disposed on the second side D2 with respect to the cylindrical portion through-hole 26b of the cylindrical portion 26.

[0028] It is preferable that the outer diameter of the portion of the resin connection portion 37 on the second side D2 increases as it approaches the flange portion . The resin joint portion 36 has a resin connection portion 37 and a flange portion 38 which are integrally formed from a synthetic resin such as polyethylene.

[0029] A male thread 41a is formed on the outer circumferential surface of the cap nut 41. A nut through-hole (not shown) serving as an assembly hole is formed on a surface 41b of the cap nut 41 facing the first side D1. The nut through hole penetrates the cap nut 41 in the direction of the axis O1. The nut through hole may be a recessed portion that does not penetrate the cap nut 41. When viewed in the direction of the axis O1, the nut through hole has an elliptical shape. In this example, a plurality of nut through holes are formed in the cap nut 41. The plurality of nut through holes are arranged at intervals around the axis O1. The multiple nut through holes have a shape that allows a specially shaped tool, rather than a general-purpose tool such as a pipe wrench, to be inserted. By inserting the specially shaped tool into the multiple nut through holes and rotating the cap nut 41 around the axis O1 relative to the cylindrical portion 26, the cap nut 41 can be removed from the cylindrical portion 26. For example, the cap nut 41 can be formed from the same material as the metal joint portion 21 . The number of nut through holes formed in the cap nut 41 may be one.

[0030] 2, the cap nut 41 is disposed on the axis O1 between the resin connection portion 37 and the cylindrical portion 26. The male thread 41a of the cap nut 41 is engaged with the female thread 26a of the cylindrical portion 26. The cap nut 41 is in contact with the flange portion 38 from the first side D1 of the flange portion 38. The cap nut 41 is disposed within a range in which the tubular portion 26 is disposed in the direction of the axis O1. In other words, the face 41b, which is the end of the first side D1 of the cap nut 41, is disposed on the second side D2 further than the end of the first side D1 of the tubular portion 26. In this example, the cap nut 41 is disposed so as to straddle the tubular portion through-hole 26b in the direction of the axis O1.

[0031] Note that a recess may be formed in place of the nut through-hole in the cap nut 41. The recess is formed only in the portion of the cap nut 41 on the first side D1. The surface 41b of the cap nut 41 and the end of the first side D1 of the tubular portion 26 may be disposed at the same position in the direction of the axis O1. In the dissimilar pipe joint 20 constructed as above, the metal joint portion 21 can rotate relative to the resin joint portion 36 about the axis O1.

[0032] The resin pipe is formed into a tubular shape from the same material as the resin joint portion 36. The resin pipe is connected to the resin connection portion 37 of the dissimilar pipe joint 20 by known electric fusion.

[0033] In the piping structure 1 configured as above, the metal pipe 10 is connected to the metal joint portion 21 of the dissimilar pipe joint 20 in the following procedure. Before the metal pipe 10 is connected to the dissimilar pipe joint 20, the joint locking portion 24 protrudes radially inward from the joint installation surface 22a due to the biasing force of the biasing member 23. When the pipe thread 11b of the metal pipe 10 is fitted into the joint thread 22b of the dissimilar pipe joint 20, the end of the first side D1 of the metal pipe main body 11 of the metal pipe 10 comes into contact with the surface 24a of the joint locking portion 24, as shown in Fig. 3. The fitting metal pipe main body 11 moves the joint locking portion 24 radially outward, and the joint locking portion 24 is accommodated in the recess 22c of the metal connection portion 22 against the biasing force of the biasing member 23.

[0034] When the metal pipe main body 11 is fitted up to a position where the metal connecting part 22 is located in the direction of the axis O1, the joint locking part 24 is disposed in the pipe through hole 11c of the metal pipe main body 11 by the biasing force of the biasing member 23, as shown in Fig. 2. In this way, the joint locking part 24 engages with the peripheral part of the pipe through hole 11c in the metal pipe main body 11, and the tightening amount of the metal pipe 10 fitted into the metal connecting part 22 is adjusted.

[0035] Next, a procedure for constructing the dissimilar pipe joint 20 configured as above will be described. As shown in FIG. 4, for example, a case in which a resin pipe 111 and an elbow 112 are placed on the ground 100 will be described. For example, the plastic pipe 111 is formed of the same material as the plastic joint portion 36. The plastic pipe 111 is placed on the ground 100 along a horizontal plane.

[0036] For example, the elbow 112 is a known electric fusion joint, and includes an elbow body 112a, a heating wire (not shown), and a pair of terminals. The elbow body 112a is formed in a curved pipe shape with a central angle of 90°. The heating wire is embedded in the elbow body 112a. A pair of terminals is provided on the outer surface of the elbow body 112a. The pair of terminals is connected to the ends of the heating wire, respectively. An end of the resin pipe 111 is connected to a first end of the elbow body 112 a of the elbow 112 .

[0037] The resin connection portion 37 of the resin joint portion 36 of the dissimilar pipe joint 20 is connected to the elbow 112 by electric fusion. Specifically, the end portion of the first side D1 of the resin connection portion 37 is inserted into a second end portion of the elbow body 112a of the elbow 112, the second end portion being opposite to the first end portion. A pair of cables of a known electric fusion device (not shown) is connected to a pair of terminals of the elbow 112. The electric fusion device is operated to apply power to the heating wire via the pair of cables and the pair of terminals. The heating wire generates heat, causing the elbow body 112a and the end of the first side D1 of the resin connection portion 37 to be fused to each other. Even at this time, the metal joint portion 21 can rotate relative to the resin joint portion 36 about the axis O1.

[0038] 5, using a known tool (not shown), the pipe thread 11b of the metal pipe 10 is fitted into the joint thread 22b of the dissimilar pipe joint 20. At this time, the joint locking portion 24 of the dissimilar pipe joint 20 engages with the peripheral portion of the pipe through hole 11c in the metal pipe body 11. The dissimilar pipe joints 20 and the like are buried in soil 103 as appropriate and then installed.

[0039] As described above, in the dissimilar pipe joint 20 of this embodiment, the metal pipe 10 can be connected to the metal connecting portion 22 by, for example, engaging the pipe thread 11b of the metal pipe 10 with the joint thread 22b of the metal connecting portion 22 of the metal joint portion 21. At this time, by sinking the joint locking portion 24 radially outward into the metal connecting portion 22 against the biasing force, the joint locking portion 24 does not interfere with the connection between the metal connecting portion 22 and the metal pipe 10. For example, the joint locking portion 24, which protrudes radially inward relative to the metal connection portion 22, engages with the peripheral portion of the pipe through hole 11c in the metal pipe 10, thereby preventing the metal pipe 10 from moving in the direction of the axis O1 relative to the metal connection portion 22. For example, the resin connection portion 37 is connected to the resin pipe 111. Therefore, the amount of tightening of the metal pipe 10 fitted into the metal connection portion 22 can be adjusted.

[0040] The joint locking portion 24 is disposed at an end of the first side D1 of the metal connection portion 22. As a result, the length in the axis O1 direction of the portion where the joint thread 22b and the pipe thread 11b are fitted together is longer on the second side D2 than the joint locking portion 24. This makes it possible to more reliably prevent the fluid flowing through the dissimilar pipe joint 20 from leaking to the outside of the dissimilar pipe joint 20 through the pipe through hole 11c and between the joint thread 22b and the pipe thread 11b. The joint installation surface 22a is the inner peripheral surface of the metal connection portion 22. The joint locking portion 24 protrudes radially inward from the metal connection portion 22, and does not protrude radially outward from the metal connection portion 22. This makes it possible to prevent the joint locking portion 24 from becoming an obstacle when handling the dissimilar pipe joint 20 alone.

[0041] In the piping structure 1 of this embodiment, the metal pipe 10 can be connected to the metal connecting portion 22 by fitting the pipe thread 11b of the metal pipe main body 11 of the metal pipe 10 into the joint thread 22b of the metal connecting portion 22 of the metal joint portion 21. At this time, by inserting the joint locking portion 24 radially outward into the metal connecting portion 22 against the biasing force, the joint locking portion 24 does not interfere with the connection between the metal connecting portion 22 and the metal pipe 10. The joint locking portion 24, which protrudes radially inward relative to the metal connection portion 22, engages with the peripheral portion of the pipe through hole 11c in the metal pipe main body 11, preventing the metal pipe main body 11 from moving in the direction of the axis O1 relative to the metal connection portion 22. Therefore, the amount of tightening of the metal pipe 10 fitted into the metal connection portion 22 can be adjusted.

[0042] In the above description, the pipe opening is a pipe through hole 11c that radially penetrates the peripheral wall of the metal pipe body 11. However, the pipe opening may be a pipe hole that does not radially penetrate the peripheral wall of the metal pipe body 11. The joint locking portion 24 may be disposed at an end of the metal connection portion 22 on the second side D2, or the like.

[0043] The configurations of the dissimilar pipe joint 20 and the piping structure 1 of this embodiment can be modified in various ways, as described below. The pipe installation surface of the metal connection part may be the outer circumferential surface of the metal connection part. In this case, as shown by the two-dot chain line L1 in Fig. 2, the metal pipe main body of the metal pipe of the piping structure of the first modified example covers the metal connection part of the dissimilar pipe joint from the radial outside. A joint thread, which is a male thread, is formed on a pipe installation surface, which is an outer circumferential surface of the metal connection part. The joint locking part is capable of protruding and retracting radially outward from the joint installation surface relative to the metal connection part. A pipe thread, which is a female thread, is formed on a pipe installation surface, which is an inner peripheral surface of a metal pipe body of the metal pipe. A pipe through hole is formed on this pipe installation surface. The joint thread of the metal connection part is fitted with the pipe thread of the metal pipe. The joint locking part engages with the peripheral edge of the pipe through hole in the metal pipe body.

[0044] 6, a dissimilar pipe joint 50 may be provided instead of the dissimilar pipe joint 20 of the piping structure 1. The dissimilar pipe joint 50 has a metal joint portion 51 and a resin joint portion 56. The metal joint portion 51 has a cylindrical portion 52 instead of the connection portion 25 and the cylindrical portion 26 of the metal joint portion 21 . The peripheral wall of the cylindrical portion 52 is thicker than the peripheral wall of the metal connection portion 22. The cylindrical portion 52 is disposed on the first side D1 relative to the metal connection portion 22 and coaxially with the axis O1.

[0045] The resin joint portion 56 has a resin connection portion 57. A portion of the second side D2 of the resin connection portion 57 is embedded in the peripheral wall of the cylindrical portion 52. The cylindrical portion 52 and the resin connection portion 57 are connected to each other by a concave-convex structure 59. In the dissimilar pipe joint 50 constructed as above, the metal joint portion 51 cannot rotate relative to the resin joint portion 56 around the axis O1. The piping structure of the first modified example and the piping structure 2 of the second modified example can also achieve the same effects as those of the piping structure 1 of the present embodiment.

[0046] Second embodiment Next, a second embodiment of the present invention will be described with reference to FIG. 7. The same components as those in the above embodiment are given the same reference numerals, and the description thereof will be omitted. Only the differences will be described. As shown in FIG. 7, a piping structure 3 of this embodiment includes a metal pipe 65 and a dissimilar pipe joint 75 of this embodiment. The metal tube 65 has a metal tube main body 66 , a biasing member 67 , and a tube locking portion 68 . The metal pipe body 66 has a recess 66a formed therein instead of the pipe through-hole 11c in each configuration of the metal pipe body 11. The recess 66a is formed in the pipe installation surface 11a, which is the outer circumferential surface of the metal pipe body 66, and does not penetrate the peripheral wall of the metal pipe body 66 in the radial direction.

[0047] For example, the urging member 67 is a helical spring. The urging member 67 is disposed in the recess 66a of the metal tube main body 66. A radially inner end of the urging member 67 is fixed to the bottom surface of the recess 66a. For example, the tube locking portion 68 is cylindrical with an axis along the radial direction. It is preferable that a surface 68a of the tube locking portion 68 facing the first side D1 is gradually inclined toward the second side D2 as it moves radially outward.

[0048] The tube locking portion 68 is disposed radially outward from the biasing member 67. The radially outer end of the biasing member 67 is fixed to the tube locking portion 68. When the biasing member 67 contracts radially, the tube locking portion 68 can be accommodated in the recess 66a of the metal pipe main body 66. At this time, the tube locking portion 68 is biased so as to protrude radially outward relative to the metal pipe main body 66. That is, the pipe engaging portion 68 can protrude and retract radially outward from the pipe installation surface 11 a relative to the metal pipe main body 66 .

[0049] The metal pipe 65 is fitted into a dissimilar pipe joint 75. The dissimilar pipe joint 75 has a metal joint portion 76 instead of the metal joint portion 21 in each of the configurations of the dissimilar pipe joint 20. The metal joint portion 76 has a metal connecting portion 77 instead of the metal connecting portion 22 in each of the configurations of the metal joint portion 21. The metal connection portion 77 has a joint hole (joint opening) 77a formed in place of the recess 22c in each configuration of the metal connection portion 22. The joint hole 77a is formed in a joint installation surface 22a, which is the inner peripheral surface of the metal connection portion 77. The pipe engaging portion 68 engages with the peripheral portion of a joint hole 77 a in the metal connection portion 77 .

[0050] As described above, in the dissimilar pipe joint 75 of this embodiment, the metal pipe 65 can be connected to the metal connecting portion 77 by fitting the pipe thread 11b of the metal pipe main body 66 of the metal pipe 65 into the joint thread 22b of the metal connecting portion 77 of the metal joint portion 76. At this time, by sinking the pipe locking portion 68 radially inward into the metal pipe main body 66 against the biasing force, the pipe locking portion 68 does not interfere with the connection between the metal connecting portion 77 and the metal pipe 65. The pipe locking portion 68, which protrudes radially outward from the metal pipe main body 66, engages with the peripheral edge of the joint hole 77a in the metal connection portion 77, preventing the metal pipe 65 from moving in the direction of the axis O1 relative to the metal connection portion 77. Therefore, the amount of tightening of the metal pipe 65 fitted into the metal connection portion 77 can be adjusted.

[0051] The joint opening is the joint hole 77a that does not radially penetrate the peripheral wall of the metal connection portion 77. However, the joint opening may be a joint through-hole that radially penetrates the peripheral wall of the metal connection portion 77.

[0052] Although the first and second embodiments of the present invention have been described above in detail with reference to the drawings, the specific configurations are not limited to these embodiments, and the present invention also includes modifications, combinations, deletions, etc. of the configurations within the scope of the gist of the present invention. Furthermore, it goes without saying that the configurations shown in each embodiment can be used in appropriate combinations. For example, in the piping structure 1 of the first embodiment, the dissimilar pipe joint 20 may have a plurality of joint locking portions 24. The plurality of joint locking portions 24 are arranged at intervals from one another in the direction of the axis O1. In this case, a plurality of pipe through holes 11c corresponding to the plurality of joint locking portions 24 are formed in the metal pipe 10. The piping structures 2 and 3 are similar to the piping structure 1. [Explanation of symbols]

[0053] 1,2,3 Piping structure 10,65 metal tube 11,66 Metal tube body 11a Pipe installation surface 11b Pipe thread 11c Pipe through hole (pipe opening) 20,50,75 Dissimilar pipe joints 21,51,76 Metal joints 22,77 Metallic joints 22a Joint installation surface 22b Joint screw 24 Joint locking part 36,56 Plastic joint 37,57 Resin joint 68 Pipe locking part

Claims

1. a metal joint part having a joint thread formed on a joint installation surface, which is an inner or outer circumferential surface of the metal joint part, and a joint locking part that is capable of protruding and retracting in a radial direction from the joint installation surface relative to the metal joint part and is biased to protrude in the radial direction; A resin joint portion having a resin connection portion and connected to the metal joint portion; A dissimilar pipe joint comprising:

2. The dissimilar pipe joint according to claim 1 , wherein the joint locking portion is disposed at an end of the metal connection portion on a side of the resin joint portion relative to the metal joint portion.

3. The dissimilar pipe joint according to claim 1 or 2, wherein the joint installation surface is the inner circumferential surface of the metal connection portion.

4. The dissimilar pipe joint according to claim 1 or 2, A metal pipe that fits into the dissimilar pipe joint; A piping structure comprising: The metal pipe has a piping structure in which a pipe thread that fits with the fitting thread is formed on its pipe installation surface facing the fitting installation surface, and which has a metal pipe main body formed on the pipe installation surface with a pipe opening whose peripheral portion engages with the fitting locking portion.

5. A dissimilar pipe joint; A metal pipe that fits into the dissimilar pipe joint; A piping structure comprising: The dissimilar pipe joint comprises: A metal joint part having a metal connection part in which a joint thread is formed on a joint installation surface, which is an inner or outer circumferential surface of the metal joint part, and a joint opening part is formed on the joint installation surface; A resin joint portion having a resin connection portion and connected to the metal joint portion; having The metal tube is a metal pipe body having a pipe installation surface facing the joint installation surface and a pipe thread formed thereon to mate with the joint thread; a pipe locking portion that is capable of protruding and retracting in a radial direction with respect to the metal pipe main body and is biased to protrude in the radial direction, and engages with a peripheral portion of the joint opening of the metal connection portion; A piping structure having the above structure.

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