Pipe joint

Abstract

To provide a pipe joint which inhibits a liquid flowing therein from leaking from a connection portion between a resin joint part and a metal joint part to the outside.SOLUTION: A pipe joint 1 includes: a resin joint part 10 having a fusion connection part to which a resin pipe is fused to be connected; and a metal joint part 30 including a first end part formed with a screw part, to which a metal pipe is connected by fitting of a screw, and a second end part with an outer surface covered by the resin joint part. An annular projection 34 is formed on an outer peripheral surface of the second end part of the metal joint part, and sealing corner parts 37, 38, each having a flat outer peripheral surface, are formed at at least one of end parts of the annular projection as seen in an axis O direction of the metal joint part.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a pipe joint.

Background Art

[0002] Conventionally, as a pipe joint for connecting a resin pipe and a metal pipe, for example, a pipe joint disclosed in Patent Document 1 is known. The pipe joint is configured by connecting a resin joint portion to which a resin pipe is melt-connected and a metal joint portion to which a metal pipe is connected by screw fitting.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Liquid such as drainage flows inside the pipe joint. If the seal at the connection between the resin joint portion and the metal joint portion is not sufficient, there is a risk that the liquid flowing inside the pipe joint will leak from the connection portion between the resin joint portion and the metal joint portion to the outside of the pipe joint.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a pipe joint that suppresses leakage of the liquid flowing inside from the connection portion between the resin joint portion and the metal joint portion to the outside.

Means for Solving the Problems

[0006] In order to solve the above problems, the present invention proposes the following means. The pipe joint of the present invention includes a resin joint part having a fusion joint part to which a resin pipe is fusion-connected, and a metal joint part in which a screw part to which a metal pipe is connected by screw fitting is formed at a first end, and the outer surface of a second end is covered with the resin joint part. An annular protrusion is formed on the outer peripheral surface of the second end of the metal joint part, and a sealing corner part having a flat outer peripheral surface is formed at at least one end of the annular protrusion in the axial direction of the metal joint part. The sealing corner part referred to here includes a first surface that is a part of the side surface of the annular protrusion and a second surface that is a part of the outer peripheral surface of the annular protrusion in a cross-section including the axis. The first surface and the second surface of the sealing corner part are each covered with the resin joint part. Here, the term "flat" means that the arithmetic mean roughness Ra is 500 μm or less. It is more preferable that this arithmetic mean roughness Ra is 300 μm or less, and even more preferable that it is 100 μm or less.

[0007] If liquid leaks from the connection part between the resin joint part and the metal joint part in the pipe joint, the liquid flows toward the outside of the pipe joint through the flow paths formed between the first surface and the resin joint part and between the second surface and the resin joint part. Since the direction of liquid flow changes greatly between the space between the first surface and the resin joint part and the space between the second surface and the resin joint part, the pressure loss when the liquid flows from one of the space between the first surface and the resin joint part and the space between the second surface and the resin joint part to the other increases. Therefore, it becomes difficult for the liquid to flow from one of the space between the first surface and the resin joint part and the space between the second surface and the resin joint part to the other. Therefore, it is possible to suppress the liquid flowing in the pipe joint from leaking to the outside of the pipe joint from the connection part between the resin joint part and the metal joint part.

[0008] Further, in the pipe joint, the sealing corner parts may be respectively formed at both ends of the annular protrusion in the axial direction. According to this invention, since the leakage of liquid can be suppressed by the sealing corner parts formed at both ends of the annular protrusion in the axial direction, the leakage of liquid can be more reliably suppressed.

[0009] Further, in the pipe joint, the positions of the end on the second end side in the axial direction of the metal joint portion and the end on the second end side in the axial direction of the annular protrusion may be the same as each other. According to this invention, for example, at the end on the second end side in the axial direction of the metal joint portion, the connection portion between the resin joint portion and the metal joint portion in the pipe joint is located. Therefore, at a position close to the connection portion between the resin joint portion and the metal joint portion, that is, at the upstream side portion of the flow path where there is a risk of liquid leakage from the inside of the pipe joint, it is possible to suppress the leakage of liquid by the sealing corner portion.

[0010] Further, in the pipe joint, the sealing corner portion is formed at the end on the first end side in the axial direction of the annular protrusion, and the outer peripheral surface on the second end side in the axial direction of the annular protrusion may gradually decrease in outer diameter toward the second end side. According to this invention, for example, when manufacturing the pipe joint by insert molding, it is possible to facilitate the resin for forming the resin joint portion to wrap around the radially outer side of the portion on the second end side of the annular protrusion of the metal joint portion arranged in the mold. And, due to the sealing corner portion formed on the first end side of the annular protrusion, it is possible to suppress the liquid flowing in the pipe joint from leaking to the outside of the pipe joint from the connection portion between the resin joint portion and the metal joint portion.

[0011] Further, in the pipe joint, a restricting portion may be provided that is arranged on the first end side in the axial direction with respect to the sealing corner portion and restricts the rotation of the metal joint portion around the axis with respect to the resin joint portion. According to this invention, at a position where the leakage of liquid from the inside of the pipe joint is suppressed by the sealing corner portion, it is possible to make it difficult for the metal joint portion to rotate around the axis with respect to the resin joint portion.

[0012] Further, another pipe joint of the present invention includes a resin joint portion having a fusion connection portion to which a resin pipe is fusion-connected, and a metal joint portion in which a screw portion is formed at the first end for connecting a metal pipe by screw fitting, and the outer surface of the second end is covered by the resin joint portion. A sealing corner portion having a flat outer peripheral surface is formed at the second end of the metal joint portion. The sealed corner mentioned here includes a first surface that is a part of the end face in the axial direction of the metal joint part in a cross section including the axis of the metal joint part, and a second surface that is a part of the outer peripheral surface of the metal joint part. The first surface and the second surface of the sealed corner are each covered by a resin joint part.

[0013] If liquid leaks from the connection part between the resin joint part and the metal joint part inside the pipe joint, the liquid will flow toward the outside of the pipe joint through the flow paths formed between the first surface and the resin joint part and between the second surface and the resin joint part. Since the direction of liquid flow changes greatly between the first surface and the resin joint part and between the second surface and the resin joint part, the pressure loss when the liquid flows from one of the first surface and the resin joint part and the second surface and the resin joint part to the other increases. Therefore, it becomes difficult for the liquid to flow from one of the first surface and the resin joint part and the second surface and the resin joint part to the other. Therefore, it is possible to suppress the liquid flowing inside the pipe joint from leaking to the outside of the pipe joint from the connection part between the resin joint part and the metal joint part.

Effect of the Invention

[0014] According to the pipe joint of the present invention, it is possible to suppress the liquid flowing inside from leaking to the outside from the connection part between the resin joint part and the metal joint part.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0016] Hereinafter, an embodiment of the pipe joint according to the present invention will be described with reference to FIGS. 1 to 12. As shown in FIG. 1, the pipe joint 1 of the present embodiment is a so-called socket type joint (conversion joint) that connects a resin pipe 200 and a metal pipe 210. In FIG. 1, the resin pipe 200 and the metal pipe 210 are shown by a two-dot chain line. In FIGS. 1 and FIGS. 3, 5, 7, 9 to 12 described later, only a cross section of a part of the metal joint parts 30, 70 described later is shown. Hereinafter, the resin pipe 200 and the metal pipe 210 will be described first.

[0017] The resin pipe 200 is formed of polybutene resin, high-density polyethylene resin, medium-density polyethylene resin, polypropylene resin, cross-linked polyethylene resin, cross-linked polybutene resin, or the like. The metal pipe 210 includes a cylindrical base 211 and a multilayer pipe 212. Note that what is connected to the pipe joint 1 is not limited to the metal pipe 210, and may be instruments such as a pressure gauge, a flow meter, and a thermometer having a metal threaded portion. On the outer peripheral surface of the first end portion of the base 211, an external male screw portion 214 is formed. The second end portion of the base 211, which is on the side opposite to the first end portion, is a connection portion 215 with the multilayer tube 212. Between the external male screw portion 214 and the connection portion 215 in the base 211, a tube engagement portion 216 for engaging a spanner or the like is formed. Although not shown in the figure, the multilayer tube 212 is formed by laminating a polyethylene resin layer, an aluminum layer, etc., which are formed in a tubular shape, in the radial direction. The end portion of the multilayer tube 212 is externally fitted to the connection portion 215 of the base 211. Note that the configuration of the metal tube 210 is not limited to this.

[0018] Next, the pipe joint 1 will be described. The pipe joint 1 includes a resin joint portion 10 and a metal joint portion 30. The resin joint portion 10 is an EF (electrofusion) joint for connecting the resin pipe 200. The resin joint portion 10 and the metal joint portion 30 are each formed in a cylindrical shape. The resin joint portion 10 and the metal joint portion 30 are connected to each other in a state where they are arranged on a common axis and are displaced in the direction along this axis. Hereinafter, this common axis will be referred to as the axis O. The direction perpendicular to the axis O is referred to as the radial direction, and the direction of orbiting around the axis O is referred to as the circumferential direction. The side of the metal joint portion 30 with respect to the resin joint portion 10 is referred to as the tip side, and the side of the resin joint portion 10 with respect to the metal joint portion 30 is referred to as the base end side. FIG. 1 is a cross-sectional view including the axis O.

[0019] The resin joint portion 10 includes a joint body 11, a locking portion 12, a heating wire 13, a terminal pin 14, and a boss 15. The joint body 11 is formed in a cylindrical shape. The joint body 11 is arranged on the axis O. The inner diameter of the portion of the joint body 11 on the base end side with respect to the locking portion 12 and the outer diameter of the resin pipe 200 are equal to each other. The locking portion 12 is formed in an annular shape and is disposed at an intermediate portion in the axial direction O on the inner peripheral surface of the joint body 11. The locking portion 12 is disposed on the axis O. As shown in FIG. 2, an engaging protrusion 12a protruding toward the tip side is formed on the side surface of the tip side of the locking portion 12. The engaging protrusion 12a is formed in an annular shape and is disposed coaxially with the locking portion 12.

[0020] The heating wire 13 is formed of, for example, a nichrome wire. The heating wire 13 is configured by forming a nichrome wire in a coil shape, and is disposed at a portion on the base end side of the locking portion 12 on the inner peripheral surface of the joint body 11 as shown in FIG. 1. The resin joint portion 10 includes a pair of terminal pins 14. Note that a pair of terminal pins 14, a portion on the base end side of the locking portion 12 in the joint body 11, and the heating wire 13 constitute a fusion connection portion 16 to which the resin tube 200 is fusion-connected. The pair of terminal pins 14 are disposed at a portion on the base end side of the locking portion 12 on the outer peripheral surface of the joint body 11. The pair of terminal pins 14 are spaced apart from each other in the axial direction O. Both ends of the heating wire 13 are electrically connected to the pair of terminal pins 14, respectively. The boss 15 is formed in a cylindrical shape and is provided on the outer peripheral surface of the joint body 11. The boss 15 surrounds each terminal pin 14.

[0021] As shown in FIGS. 1 and 2, engaging grooves 18, 19, and 20 are formed in a portion on the tip side of the locking portion 12 on the inner peripheral surface of the joint body 11. The engaging grooves 18, 19, and 20 are arranged at intervals in this order from the base end side toward the tip side. The engaging groove 20 opens toward the tip side. A small-diameter portion 22 is formed on the outer peripheral surface of the tip portion of the joint body 11. The outer diameter of the small-diameter portion 22 is smaller than the outer diameter of the portion of the joint body 11 that continues to the base end side with respect to the small-diameter portion 22. A caulking ring 23 is attached to the outer peripheral surface of the small-diameter portion 22. The caulking ring 23 suppresses the resin joint portion 10 that covers the radially outer side of a connecting portion 31 (to be described later) of the metal joint portion 30 from moving radially outward from the connecting portion 31. The joint body 11, the locking portion 12, and the boss 15 are integrally formed of the same material as the resin tube 200.

[0022] As shown in FIG. 1, on the outer peripheral surface of the joint body 11, in the portion located between the pair of terminal pins 14, a small projection 25 for an indicator is arranged. The small projection 25 is arranged in a hole formed in the outer peripheral surface of the joint body 11. When the connection between the resin joint portion 10 and the resin tube 200 is properly made, the small projection 25 projects outward in the radial direction.

[0023] The metal joint portion 30 is formed of a metal such as brass. As shown in FIGS. 1 and 2, the metal joint portion 30 includes a connecting portion 31, a clamping portion 32, a screw connection portion 33, a first annular projection (annular projection) 34, and a second annular projection 35. The connecting portion 31, the clamping portion 32, and the screw connection portion 33 are each formed in a cylindrical shape. The connecting portion 31, the clamping portion 32, and the screw connection portion 33 are arranged on the axis O in this order from the base end side to the tip end side. The connecting portion 31 is formed at the base end portion (second end portion) of the metal joint portion 30. The screw connection portion 33 is formed at the tip end portion (first end portion) of the metal joint portion 30. The tip end portion of the metal joint portion 30 is the end portion on the side opposite to the base end portion of the metal joint portion 30. In the metal joint portion 30, the direction from the connecting portion 31 toward the screw connection portion 33 is the tip end side, and the direction from the screw connection portion 33 toward the connecting portion 31 is the base end side.

[0024] The inner diameters of the connecting portion 31 and the clamping portion 32 are about the same as each other. The outer diameter of the connecting portion 31 is smaller than the outer diameter of the clamping portion 32. On the outer peripheral surface of the base end portion of the connecting portion 31, an engaging groove 31a is formed. The engaging groove 31a opens toward the base end side. The radially outer surface of the connecting portion 31 is covered by the joint body 11 of the resin joint portion 10. As shown in Fig. 2, the first annular protrusion 34 is formed in an annular shape. The first annular protrusion 34 is coaxially arranged with the connecting portion 31 on the outer peripheral surface of the base end portion of the connecting portion 31. The first annular protrusion 34 is formed over the entire circumference at the base end portion of the connecting portion 31. The positions of the base end of the connecting portion 31 and the base end of the first annular protrusion 34 in the direction of the axis O are equal to each other. The radially outer side of the engagement groove 31a is covered by the first annular protrusion 34. The outer peripheral surface (the surface on the radially outer side), the inner peripheral surface (the surface on the radially inner side), and the side surfaces (each end surface in the direction of the axis O) of the first annular protrusion 34 are all flat. No knurling groove described later is formed on the surface of the first annular protrusion 34.

[0025] Sealing corners 37 and 38 with flat outer peripheral surfaces are respectively formed at both ends of the first annular protrusion 34 in the direction of the axis O. That is, a sealing corner 37 is formed at the base end portion of the first annular protrusion 34, and a sealing corner 38 is formed at the tip end portion of the first annular protrusion 34. The sealing corners 37 and 38 are respectively formed over the entire circumference of the first annular protrusion 34. The sealing corner 37 includes a first surface 37a which is a part of the side surface on the base end side of the first annular protrusion 34 and a second surface 37b which is a part of the outer peripheral surface of the first annular protrusion 34. The sealing corner 38 includes a first surface 38a which is a part of the side surface on the tip end side of the first annular protrusion 34 and a second surface 38b which is a part of the outer peripheral surface of the first annular protrusion 34. The first surface 37a is the radially outer portion on the side surface on the base end side of the first annular protrusion 34. The second surface 37b is the base end portion of the outer peripheral surface of the first annular protrusion 34. The first surface 38a is the radially outer portion on the side surface on the tip end side of the first annular protrusion 34. The second surface 38b is the tip end portion of the outer peripheral surface of the first annular protrusion 34.

[0026] In the cross-section including the axis O shown in Fig. 2, the first surface 37a and the first surface 38a are substantially orthogonal to the axis O. The second surface 37b and the second surface 38b are along the axis O. The angle θ1 formed by the tangent line at the end of the first surface 37a that is continuous with the second surface 37b and the tangent line at the end of the second surface 37b that is continuous with the first surface 37a inside the sealing corner 37 is preferably 30 degrees or more and 110 degrees or less. This angle is more preferably 60 degrees or more and 100 degrees or less, and even more preferably 85 degrees or more and 95 degrees or less. The angle θ2 formed by the tangent line at the end of the first surface 38a that is continuous with the second surface 38b and the tangent line at the end of the second surface 38b that is continuous with the first surface 38a inside the sealing corner 37 is the same as the angle θ1. The first annular protrusion 34 is disposed in the engagement groove 18 of the joint body 11. An engagement protrusion 12a of the locking portion 12 is disposed in the engagement groove 31a of the connecting portion 31. The surface of the first annular protrusion 34 is covered by the joint body 11. In the pipe joint 1, the so-called single-peak type first annular protrusion 34 suppresses the leakage of drainage described later.

[0027] The second annular protrusion 35 is formed in an annular shape. The second annular protrusion 35 is coaxially disposed at a position between the first annular protrusion 34 and the clamp portion 32 on the outer peripheral surface of the connecting portion 31. The outer diameter of the second annular protrusion 35 and the outer diameter of the first annular protrusion 34 are equal to each other. A knurl groove (knurl, restricting portion) 35a is formed on the outer peripheral surface of the second annular protrusion 35. The type of the knurl groove 35a is not particularly limited, but the type of the knurl groove 35a is, for example, the diamond pattern m0.5 defined in JIS B 0951:1962. In this case, when the outer diameter of the knurl groove 35a is sufficiently large, the groove depth in the knurl groove 35a is 0.652 mm (652 μm) according to the formula (0.326×2). The knurl groove 35a is formed over the entire range in the axial direction O on the outer peripheral surface of the second annular protrusion 35. The knurl groove 35a is disposed on the tip side of the sealing corners 37, 38. The second annular protrusion 35 is disposed in the engagement groove 19 of the joint body 11. The surface of the second annular protrusion 35 is covered by the joint body 11. A part of the joint body 11 enters into the groove of the knurl groove 35a, thereby restricting the rotation of the connecting part 31 of the metal joint part 30 around the axis O with respect to the resin joint part 10.

[0028] As shown in FIGS. 1 and 2, the outer diameter of the clamp part 32 is approximately the same as the outer diameter of the second annular protrusion 35 and the outer diameter of the resin pipe 200, respectively. The base end part of the clamp part 32 is arranged in the engagement groove 20 of the joint body 11. A knurl groove 32a is formed on the outer peripheral surface of the base end part of the clamp part 32. The knurl groove 32a is arranged in the engagement groove 20 of the joint body 11. The type of the knurl groove 32a is not particularly limited, but for example, it is the same as the type of the knurl groove 35a. A part of the joint body 11 enters into the groove of the knurl groove 32a, thereby restricting the rotation of the connecting part 31 of the metal joint part 30 around the axis O with respect to the resin joint part 10. The outer peripheral surface of the clamp part 32 other than the knurl groove 32a is exposed to the outside.

[0029] As shown in FIG. 1, a female screw part (screw part) 33a is formed on the inner peripheral surface of the screw connection part 33. The male screw part 214 of the metal pipe 210 is screw-fitted and connected to the female screw part 33a. When viewed in the direction of the axis O, the outer peripheral surface of the screw connection part 33 is hexagonal. The outer diameter of the screw connection part 33 is larger than the outer diameter of the clamp part 32. The diameter of the inscribed circle of the outer peripheral surface of the screw connection part 33 is larger than the outer diameter of the clamp part 32. The surfaces of the metal joint part 30 other than the knurl groove 35a, the knurl groove 32a, and the screw connection part 33 are flat. The internal space of the resin joint part 10 and the internal space of the metal joint part 30 communicate with each other.

[0030] The process of connecting the resin pipe 200 and the metal pipe 210 to the pipe joint 1 is performed as follows. Scrape the outer peripheral surface of the end of the resin tube 200 with a scraper (not shown), and insert this end of the resin tube 200 into the fusion connection part 16 of the pipe joint 1. In order to temporarily fix the pipe joint 1 and the resin tube 200, use a known clamp (not shown) to grip the clamp part 32 of the metal joint part 30 and the resin tube 200 respectively. When electric current is passed between the pair of terminal pins 14, the joint body 11 of the resin joint part 10 and the resin tube 200 are melted by the heating wire 13. Thereby, the pipe joint 1 and the resin tube 200 are connected. The small protrusion 25 protrudes outward in the radial direction. On the other hand, fit the male pipe thread part 214 of the metal pipe 210 to the screw connection part 33 of the metal joint part 30. Attach a first wrench to the outer peripheral surface of the screw connection part 33 of the metal joint part 30, and attach a second wrench to the pipe engagement part 216 of the metal pipe 210. Rotate the second wrench relative to the first wrench in a predetermined direction around the axis O. The male pipe thread part 214 is tightened to the screw connection part 33, and the pipe joint 1 and the metal pipe 210 are connected.

[0031] Next, the operation of the pipe joint 1 configured as described above will be described. For example, when a liquid flows from inside the metal pipe 210 into the pipe joint 1, this liquid flows into the resin tube 200 through the pipe joint 1. At this time, there is a risk that drainage may leak to the outside of the pipe joint 1 from the connection part R1 (see FIG. 2) between the resin joint part 10 and the metal joint part 30 in the pipe joint 1 through the boundary part between the resin joint part 10 and the metal joint part 30.

[0032] On the other hand, according to the pipe joint 1 of the present embodiment, if liquid leaks from the connection portion R1 in the pipe joint 1, the liquid flows through the flow paths formed between the first surface 37a and the joint body 11 of the resin joint portion 10 and between the second surface 37b and the joint body 11, and flows toward the outside of the pipe joint 1. Since the direction of the liquid flow changes greatly between the first surface 37a and the joint body 11 and between the second surface 37b and the joint body 11, the pressure loss when the liquid flows from between the first surface 37a and the joint body 11 toward between the second surface 37b and the joint body 11 increases. Therefore, it becomes difficult for the liquid to flow from between the first surface 37a and the joint body 11 toward between the second surface 37b and the joint body 11. Similarly, when the liquid passes through the flow paths formed between the first surface 38a of the sealing corner portion 38 and the joint body 11 and between the second surface 38b and the joint body 11, it also becomes difficult to flow. Therefore, it is possible to suppress the liquid flowing in the pipe joint 1 from leaking from the connection portion R1 between the resin joint portion 10 and the metal joint portion 30 to the outside of the pipe joint 1. The water tightness of the pipe joint 1 can be improved.

[0033] Sealing corner portions 37 and 38 are respectively formed at both ends in the direction of the axis O of the first annular protrusion 34. Since the leakage of the liquid can be suppressed by the sealing corner portions 37 and 38 formed at both ends in the direction of the axis O of the first annular protrusion 34, the leakage of the liquid can be more reliably suppressed. The positions of the base ends of the connecting portion 31 and the base ends of the first annular protrusion 34 are equal to each other. The connection portion R1 in the pipe joint 1 is located at the base end of the metal joint portion 30. Therefore, at a position close to the connection portion R1, that is, at the upstream side portion of the flow path where there is a risk of liquid leakage from the pipe joint 1, the leakage of the liquid can be suppressed by the sealing corner portions 37 and 38. The pipe joint 1 is provided with a knurled groove 35a on the tip side of the sealing corner portions 37 and 38. At the position where the leakage of the liquid from the pipe joint 1 is suppressed by the sealing corner portions 37 and 38, it is possible to make it difficult to rotate the metal joint portion 30 around the axis O with respect to the resin joint portion 10.

[0034] The pipe joint 1 of this embodiment can have its configuration variously modified as described below. As in the pipe joint 1A of the first modification shown in FIGS. 3 and 4, in the pipe joint 1 of this embodiment, an engaging groove 31a may not be formed in the connecting portion 31 of the metal joint portion 30, and a groove portion 34a may be formed in an intermediate portion in the axial direction O on the outer peripheral surface of the first annular projection 34. The groove portion 34a is formed over the entire circumference of the first annular projection 34. The distance between the bottom surface of the groove portion 34a and the axis O is longer than half of the outer diameter of the connecting portion 31. That is, in the radial direction, the bottom surface of the groove portion 34a does not reach the outer peripheral surface of the connecting portion 31. In the pipe joint 1A, drainage leakage is suppressed by the so-called single-peak type first annular projection 34 with a recess.

[0035] As in the pipe joint 1B of the second modification shown in FIGS. 5 and 6, in the pipe joint 1 of this embodiment, the third surface 34b, which is the outer peripheral surface on the proximal end side of the first annular projection 34, may gradually decrease in outer diameter toward the proximal end side. In this modification, a sealing corner portion 37 is not formed on the first annular projection 34, and a sealing corner portion 38 is formed at the tip of the first annular projection 34. For example, when manufacturing the pipe joint 1B by insert molding, the resin for forming the resin joint portion 10 can easily flow around the outer side in the radial direction of the third surface 34b of the first annular projection 34 of the metal joint portion 30 disposed in the mold. Then, the sealing corner portion 38 formed at the tip of the first annular projection 34 can suppress the liquid flowing in the pipe joint 1B from leaking to the outside of the pipe joint 1B from the connection portion R1 between the resin joint portion 10 and the metal joint portion 30.

[0036] Similar to the pipe joint 1C of the third modification example shown in FIG. 7, in addition to each component of the pipe joint 1 of the present embodiment, a first annular protrusion (annular protrusion) 41 may be provided. The first annular protrusion 41 has the same configuration as the first annular protrusion 34. That is, the third surface 41a, which is the outer peripheral surface on the proximal end side of the first annular protrusion 41, gradually decreases in outer diameter as it goes toward the proximal end side. A sealing corner portion 42 with a flat outer peripheral surface is formed at the tip of the first annular protrusion 41. The first annular protrusion 41 is disposed between the first annular protrusion 34 and the second annular protrusion 35, with an interval between the first annular protrusion 34 and the second annular protrusion 35 respectively. In the pipe joint 1C, the so-called double-mountain type first annular protrusions 34 and 41 suppress drainage leakage.

[0037] Similar to the pipe joint 1D of the fourth modification example shown in FIG. 8, in the pipe joint 1 of the present embodiment, the metal joint portion 30 may be provided with a second annular protrusion 45 instead of the first annular protrusion 34. In this modification example, the second annular protrusion 35 is disposed at a position spaced a predetermined distance from the proximal end surface of the connecting portion 31 toward the distal end side. A sealing corner portion 46 with a flat outer peripheral surface is formed at the proximal end portion of the connecting portion 31 (metal joint portion 30). The sealing corner portion 46 includes a first surface 46a that is a part of the proximal end surface of the connecting portion 31 and a second surface 46b that is a part of the outer peripheral surface of the connecting portion 31. The first surface 46a is the radially outer portion of the proximal end surface of the connecting portion 31. The second surface 46b is the proximal end portion of the outer peripheral surface of the connecting portion 31. In the cross section including the axis O shown in FIG. 8, the first surface 46a is substantially orthogonal to the axis O. The second surface 46b is along the axis O. The angle θ4 formed inside the sealing corner portion 46 by the tangent line at the end portion of the first surface 46a continuous with the second surface 46b and the tangent line at the end portion of the second surface 46b continuous with the first surface 46a is configured in the same manner as the angle θ1.

[0038] The second annular protrusion 45 has the same configuration as the second annular protrusion 35. That is, a knurl groove 45a having the same configuration as the knurl groove 35a is formed on the outer peripheral surface of the second annular protrusion 45. The second annular protrusion 45 is disposed with a gap between the second annular protrusion 35 and the clamp portion 32, respectively, between the second annular protrusion 35 and the clamp portion 32. The first surface 46a and the second surface 46b of the connecting portion 31 are each covered by the joint body 11.

[0039] If liquid leaks from the connection portion R1 between the resin joint portion 10 and the metal joint portion 30 in the pipe joint 1D, the liquid passes through the flow paths formed between the first surface 46a and the joint body 11 and between the second surface 46b and the joint body 11, and flows toward the outside of the pipe joint 1D. Since the direction of liquid flow changes greatly between the first surface 46a and the joint body 11 and between the second surface 46b and the joint body 11, the pressure loss when the liquid flows from between the first surface 46a and the joint body 11 toward between the second surface 46b and the joint body 11 increases. Therefore, it becomes difficult for the liquid to flow from between the first surface 46a and the joint body 11 toward between the second surface 46b and the joint body 11. Therefore, it is possible to suppress the liquid flowing in the pipe joint 1D from leaking from the connection portion R1 between the resin joint portion 10 and the metal joint portion 30 to the outside of the pipe joint 1D. In this way, in the pipe joint 1D, the so-called recessed sealing corner portion 46 suppresses the leakage of drainage.

[0040] In the pipe joint 1D of this modification, at least one of the knurl groove 32a and the second annular protrusions 35 and 45 may be formed.

[0041] In the pipe joint 1 of the present embodiment, like the pipe joint 1E of the fifth modification shown in FIG. 9, the metal joint portion 30 may include a first annular protrusion 41, a first annular protrusion 48, and restricting portions 49 and 50 instead of the knurl groove 32a and the second annular protrusion 35. The first annular protrusion 48 has the same configuration as the first annular protrusion 41. However, the outer diameters of the first annular protrusions 41 and 48 may be constant regardless of the position in the axial direction of the axis O. The first annular protrusion 48 is disposed between the first annular protrusion 41 and the clamp portion 32. The first annular protrusions 34, 41, 48 are spaced apart from each other in the direction of the axis O. In the pipe joint 1E, a regulating portion by a knurled groove is not formed. In the pipe joint 1E, a protruding strip-shaped regulating portion 49 extending along the direction of the axis O, and a recessed regulating portion 50 recessed from the outer peripheral surfaces of the connecting portion 31, the first annular protrusions 41, 48, and the clamp portion 32 toward the axis O are formed.

[0042] The regulating portion 49 protrudes from the outer peripheral surface of the connecting portion 31 to the middle portion of the radial length of the first annular protrusions 34, 41, 48. A plurality of regulating portions 49 are formed in the pipe joint 1E at intervals in the circumferential direction. The regulating portion 50 has a circular shape when viewed from the radially outer side so as to face the regulating portion 50. The peripheries of the plurality of regulating portions 49 are covered by the joint body 11, and a part of the joint body 11 enters into the regulating portion 50. In this way, the rotation of the connecting portion 31 of the metal joint portion 30 around the axis O with respect to the resin joint portion 10 is regulated.

[0043] Similar to the pipe joint 1F of the sixth modification shown in FIG. 10, in the pipe joint 1E of the modification, instead of the regulating portions 49, 50, a regulating portion 53 may be provided. In the pipe joint 1F of this modification, the regulating portion 53 is formed in a recessed shape recessed from the outer peripheral surface of the connecting portion 31 between the first annular protrusion 34 and the first annular protrusion 41 toward the axis O. The regulating portion 53 has a circular shape when viewed from the radially outer side so as to face the regulating portion 53. A part of the joint body 11 enters into the regulating portion 53. In this way, the rotation of the connecting portion 31 of the metal joint portion 30 around the axis O with respect to the resin joint portion 10 is regulated. Note that the position where the regulating portion 53 is formed is not limited to this, and for example, it may be the outer peripheral surface of the connecting portion 31 between the first annular protrusion 41 and the first annular protrusion 48, or the outer peripheral surface of the connecting portion 31 between the first annular protrusion 48 and the clamp portion 32.

[0044] In the following modification example, the case where the pipe joint is a joint other than the socket type will be described. The pipe joint 2 of the seventh modification example shown in FIG. 11 is a so-called branch saddle type joint. The pipe joint 2 includes a branch saddle type resin joint portion 60 and a metal joint portion 70. The resin joint portion 60 is attached to the outer surface of a pipe or the like. The resin joint portion 60 includes a semi-cylindrical main body 61 and a connection cylinder 62. A through hole 61a is formed in the outer surface of the main body 61. The connection cylinder 62 is fixed to the outer surface of the main body 61 and communicates with the through hole 61a. The metal joint portion 70 includes a connecting portion 31, a clamping portion 32, an engaging portion 71, a male screw portion (screw portion) 72, a first annular protrusion 34, and a second annular protrusion 35. The engaging portion 71 is formed in an annular shape. When viewed in the direction of the axis O, the outer peripheral surface of the engaging portion 71 is hexagonal. The connecting portion 31, the clamping portion 32, the engaging portion 71, and the male screw portion 72 are arranged in this order from the base end side to the tip end side. The metal joint portion 70 is connected to the connection cylinder 62 of the resin joint portion 60.

[0045] The pipe joint 3 of the eighth modification example shown in FIG. 12 is a so-called cheese type joint. The pipe joint 3 includes a cheese type resin joint portion 80 and a metal joint portion 70. The resin joint portion 80 includes a circular tubular main body 81 and a connection cylinder 62. A through hole 81a is formed in the outer surface of the main body 81. The connection cylinder 62 is fixed to the outer surface of the main body 81 and communicates with the through hole 81a. The metal joint portion 70 is connected to the connection cylinder 62 of the resin joint portion 80. Note that an EF joint such as the resin joint portion 10 of the present embodiment may be provided at the end of the resin joint portion 80.

[0046] As described above, although one embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and modifications, combinations, deletions, etc. of the configuration within the scope not departing from the gist of the present invention are also included.

Explanation of Reference Numerals

[0047] 1, 1A, 1B, 1C, 1D, 1E, 1F, 2, 3 pipe joint 10, 60, 80 resin joint part 16 fusion connection part 30, 70 metal joint part 33a female screw part (screw part) 34, 41, 48 first annular protrusion (annular protrusion) 32a, 35a, 45a knurled groove (restriction part) 37, 38, 42, 46 sealing corner part 49, 50, 53 restriction part 72 male screw part (screw part) 200 resin pipe 210 metal pipe O axis

Claims

1. A resin joint having a fusion joint portion where resin pipes formed of any one of polybutene resin, high-density polyethylene resin, medium-density polyethylene resin, polypropylene resin, crosslinked polyethylene resin, and crosslinked polybutene resin are fusion-connected, A metal joint having a threaded portion where a metal pipe is connected by screw fitting at the first end, and the outer surface of the second end is covered by the resin joint, Comprising: A plurality of annular protrusions are formed on the outer peripheral surface of the second end of the metal joint, Among the plurality of annular protrusions, at least one end in the axial direction of the metal joint at the first annular protrusion closest to the second end side has a sealing corner portion with a flat outer peripheral surface (however, excluding those with knurling on the surface of the first annular protrusion).

2. The pipe joint according to Claim 1, wherein the sealing corner portions are respectively formed at both ends in the axial direction of the first annular protrusion.

3. The pipe joint according to Claim 1 or 2, wherein the position of the end on the second end side in the axial direction of the metal joint and the position of the end on the second end side in the axial direction of the first annular protrusion are equal to each other.

4. The sealing corner portion is formed at the end on the first end side in the axial direction of the first annular protrusion, The pipe joint according to any one of Claims 1 to 3, wherein the outer peripheral surface of the first annular protrusion on the second end side in the axial direction gradually decreases in outer diameter toward the second end side.

5. The pipe joint according to any one of Claims 1 to 4, comprising a restricting portion that is disposed on the first end side in the axial direction of the sealing corner portion and restricts the rotation of the metal joint around the axis with respect to the resin joint.

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