Pipe fittings

Abstract

The objective is to provide a pipe fitting that can effectively prevent a resin pipe from coming out of the pipe fitting when an external force is applied to the resin pipe in the pulling direction. [Solution] The pipe joint comprises an inner core that is fitted inside the end PE of the resin pipe P and expands the diameter of the end PE, a joint body 2 into which the resin pipe P is inserted and into which a male threaded portion 2a is formed on the outer surface, a water-sealing ring 3 fitted outside the resin pipe P, and a cap nut 4 that screws onto the male threaded portion 2a of the joint body 2 and pushes the water-sealing ring 3 between the joint body 2 and the end PE of the resin pipe P, thereby pressing the water-sealing ring 3 against the end PE of the resin pipe P. The pipe joint has a configuration that fills the gap between the end PE of the resin pipe P and the joint body 2 and inner core 1.

Description

Technical Field

[0001] The present invention relates to a pipe joint for connecting resin pipes in piping facilities such as water supply pipes.

Background Art

[0002] Conventionally, in piping facilities such as water supply pipes, resin pipes such as polyethylene resin pipes have been used in consideration of cost and ease of construction, and metal pipe joints for connecting these resin pipes and other pipes are known.

[0003] As shown in FIG. 6, this pipe joint includes an in-core 1 that is fitted inside the end portion PE of the resin pipe P and expands the diameter of the end portion PE, a joint body 2 into which the resin pipe P is inserted and has a male screw portion 2a formed on its outer peripheral surface, a water stop ring 3 that is externally fitted to the resin pipe P, and a cap nut 4 that is screwed with the male screw portion 2a of the joint body 2 and presses the water stop ring 3 between the joint body 2 and the end portion PE of the resin pipe P, thereby pressing the water stop ring 3 against the end portion PE of the resin pipe P (see, for example, Patent Document 1). In the figure, the reference sign J represents the axial direction of the central axis of the resin pipe P.

[0004] Then, the construction procedure for connecting the resin pipe P using this pipe joint will be described. As shown in FIG. 7(a), first, after passing the cap nut 4 and the water stop ring 3 through the end portion PE of the resin pipe P, as shown in FIG. 7(b), the in-core 1 is driven into the end portion PE of the resin pipe P by a hammer H or the like while expanding the diameter of the end portion PE of the resin pipe P and fitting it inside. Then, as shown in FIG. 7(c), the end portion PE of the resin pipe P with the in-core 1 fitted inside is inserted into the joint body 2. Finally, as shown in FIG. 7(d), by screwing with the male screw portion 2a of the joint body 2 and pressing the water stop ring 3 between the joint body 2 and the end portion PE of the resin pipe P, the water stop ring 3 is pressed against the end portion PE of the resin pipe P, and after confirming that the tightening torque is the specified value, the construction is completed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, with such pipe fittings, there was a risk that the resin pipe P would come out of the fitting if a large external force in the pulling direction was applied to the resin pipe P due to an earthquake or the like. Specifically, as shown in Figure 8(a), when a large external force in the pulling direction is applied to the resin pipe P while it is inserted into the pipe fitting, as shown in Figure 8(b), the resin pipe P moves in the pulling direction, and the outer surface of the end PE of the resin pipe P is partially scraped by the water-sealing ring 3, causing it to curl up towards the gap G1 (black area in Figure 6) between the end PE of the resin pipe P and the fitting body 2. Then, as shown in Figure 8(c), when the outer surface of the end PE of the resin pipe P is completely scraped by the water-sealing ring 3, the flange 12 of the inner core 1 and the water-sealing ring 3 come into contact. Furthermore, as shown in Figure 8(d), if an external force in the pulling direction is continuously applied to the resin pipe P, the flange portion 12 of the inner core 1 cannot withstand the pressure of the water-stopping ring 3 and breaks, causing the resin pipe P to inadvertently detach from the pipe joint.

[0007] Furthermore, as shown in Figure 9(a), in the conventional InCore 1, the flange portion 12 extends perpendicularly along the radial direction of the InCore 1. Therefore, as shown in Figure 9(b), when the InCore 1 is fitted into the end PE of the resin pipe P, and the end PE of the resin pipe P expands in diameter toward the end face PS, as shown in Figure 9(c), a gap G2 is created between the side surface 121 of the flange portion 12 on the resin pipe P side and the end face PS of the resin pipe P, which increases radially outward. This gap G2 allows deformation of the end face of the resin pipe P, which has the problem of making it easy for the resin pipe P to come loose from the pipe joint. Moreover, as mentioned above, the InCore 1 is hammered into the end PE of the resin pipe P. However, as shown in Figure 9(c), even after the hammering is complete, a gap G2 remains between the side surface 121 of the flange portion 12 on the resin pipe P side and the end face PS of the resin pipe P. Therefore, the completion of hammering is not recognized, which can lead to over-hammering and damage to the pipe joint, or unnecessary hammering that is wasted effort.

[0008] Furthermore, as shown in Figure 9(c), the conventional inner core 1 prevents the inner core 1 from coming out of the resin pipe P by forming a plurality of annular grooves 112 at a predetermined pitch along the axial direction from the base end 11a on the flange 12 side to the tip end 11b on the tapered outer surface 111. However, this still creates a gap G3 between the end PE of the resin pipe P and the inner core 1, which allows deformation of the outermost end PE1 of the resin pipe P, resulting in the problem that the resin pipe P is more likely to come out of the pipe joint.

[0009] This invention has been made in view of the above-mentioned problems, and aims to provide a pipe joint that can prevent a resin pipe from coming out of the pipe joint when an external force in the pulling direction is applied to the resin pipe. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides a pipe joint comprising: an inner core fitted inside the end of a resin pipe to expand the diameter of the end; a joint body into which the resin pipe is inserted and into which a male threaded portion is formed on the outer surface; a water-sealing ring fitted outside the resin pipe; and a cap nut that screws onto the male threaded portion of the joint body to push the water-sealing ring between the joint body and the end of the resin pipe, thereby pressing the water-sealing ring against the end of the resin pipe, characterized in that the gap between the end of the resin pipe and the joint body and / or inner core is filled.

[0011] According to this, the structure is such that the gap between the end of the resin pipe and the fitting body and / or inner core is filled, so when an external force is applied to the resin pipe in the pulling direction, the deformation of the end of the resin pipe is restricted, and it is possible to prevent the resin pipe from coming out of the pipe fitting due to the deformation of the end of the resin pipe.

[0012] Furthermore, the water-sealing ring may have a ring body portion that is pressed against the end of the resin pipe, and an extension portion that extends axially along the end face side of the resin pipe from the ring body portion, wherein the extension portion fills the gap between the joint body and the resin pipe. In this case, since the extension portion of the water-sealing ring fills the gap between the joint body and the end of the resin pipe, deformation of the end of the resin pipe toward the pipe joint can be restricted when a large external force is applied to the resin pipe in the pulling direction. In addition, even if the resin pipe moves in the pulling direction and the outer surface of the end of the resin pipe is partially scraped by the water-sealing ring, there is no escape route for the scraped pieces, so further scraping is suppressed, and deformation of the end of the resin pipe toward the pipe joint can be sufficiently restricted.

[0013] Furthermore, the water-stopping ring may be formed in a triangular cross-section, with the extension becoming thinner as it approaches the end face of the resin pipe. This allows the extension to reliably fill the gap between the joint body and the resin pipe while suppressing interference between the extension and the joint body.

[0014] Furthermore, the water-sealing ring may have a stepped portion at the boundary between the ring body and the extension portion, wherein the inner surface on the extension portion side is larger in diameter than the inner surface on the ring body side. With this configuration, when the water-sealing ring is pushed between the joint body and the end of the resin pipe using the cap nut, the stepped portion of the water-sealing ring bites into the end of the resin pipe, thereby reliably preventing the resin pipe from coming out of the pipe joint.

[0015] Furthermore, the inner core comprises a cylindrical portion having a tapered outer surface that fits inside the end of the resin pipe and expands the diameter of the end, and a flange portion extending radially outward on the end face side of the resin pipe. The flange portion may have a side surface on the cylindrical side that is inclined toward the cylindrical portion with respect to the radial direction perpendicular to the axial direction of the cylindrical portion. This makes it easier for the side surface of the flange portion to conform to the end face of the expanded resin pipe, and the gap between the flange portion and the resin pipe is reliably filled, thereby restricting deformation of the end of the resin pipe when an external force in the pulling direction is applied to the resin pipe. Moreover, when the inner core is fitted into the end of the resin pipe by hammering in the flange portion of the inner core, the completion of the insertion can be easily confirmed by visual inspection as the gap between the flange portion and the resin pipe is filled, thus preventing damage to the pipe joint due to excessive insertion or continuing unnecessary insertion.

[0016] Furthermore, the flange portion may be inclined such that the side surface facing the cylindrical portion is inclined within a range of an angle greater than 0° and less than or equal to 10° relative to the radial direction perpendicular to the axial direction of the cylindrical portion. This ensures that the side surface of the flange portion facing the cylindrical portion is securely aligned with the end face of the resin pipe.

[0017] Furthermore, the inner core comprises a cylindrical portion having a tapered outer surface that fits inside the end of the resin pipe and expands the diameter of the end, and a flange portion extending radially outward on the end face side of the resin pipe. The cylindrical portion may have a plurality of annular grooves formed at a predetermined pitch along the axial direction from the base end to the tip on the flange side of the tapered outer surface, and a flat surface formed at the base of the base end in such a manner that the annular grooves adjacent to the flange are filled. With this configuration, the annular grooves formed on the tapered outer surface of the cylindrical portion bite into the resin pipe, thus more reliably preventing the resin pipe from coming out of the inner core. Moreover, since the flat surface at the base of the cylindrical portion follows the outer surface of the outermost end of the resin pipe, the gap between the inner core and the outermost end of the resin pipe is filled, thus restricting deformation of the end of the resin pipe toward the inner core when a large external force in the pulling direction is applied to the resin pipe.

[0018] In addition, the cylindrical portion may be formed such that the flat surface has a length of 5% to 20% with respect to the axial length of the in-core. According to this, since the flat surface at the root portion of the cylindrical portion surely follows the outermost end portion of the resin tube and the gap between the in-core and the outermost end portion of the resin tube is surely filled, when a large external force in the pulling direction is applied to the resin tube, deformation of the end portion of the resin tube toward the in-core side can be surely restricted.

Advantages of the Invention

[0019] According to the present invention, since it has a configuration in which the gap between the end portion of the resin tube and the joint body and / or the in-core is filled, when an external force in the pulling direction is applied to the resin tube, deformation of the end portion of the resin tube is restricted, and it is possible to prevent the resin tube from coming out of the pipe joint due to the deformation of the end portion of the resin tube, and it is possible to improve the reliability of the construction when installing the resin tube.

Brief Description of the Drawings

[0020] [Figure 1] It is a front view showing a pipe joint according to an embodiment of the present invention. [[ID=十六]] [[ID=十七]] [Figure 2] It is a cross-sectional view showing the pipe joint of FIG. 1. [Figure 3] It is a partial cross-sectional view showing (a) the in-core of FIG. 2 and (b) a conventional in-core. [Figure 4] It is a front view showing (a) the water stop ring of FIG. 2 and (b) a conventional water stop ring. [Figure 5] It is an enlarged cross-sectional view showing part C of the pipe joint of FIG. 2. [Figure 6] It is a cross-sectional view showing a conventional pipe joint. [Figure 7] It is a cross-sectional view showing the construction procedure of a conventional pipe joint. [Figure 8] It is a cross-sectional view showing the process in which the resin tube comes out of a conventional pipe joint. [Figure 9] It is a cross-sectional view showing the structure of a conventional in-core.

Modes for Carrying Out the Invention

[0021] Next, the pipe joint according to the present invention will be described with reference to Figures 1 to 5. In this specification, "right" refers to the right side in Figure 2, and "left" refers to the left side in Figure 2.

[0022] This pipe fitting is a metal pipe fitting for connecting a polyethylene resin pipe P to another pipe, and as shown in Figures 1 and 2, it comprises an inner core 1 that is fitted inside the end PE of the polyethylene resin pipe P and expands the diameter of the end PE, a fitting body 2 into which the resin pipe P is inserted and into which a male threaded portion 2a is formed on the outer surface, a water-sealing ring 3 that is fitted outside the resin pipe P, and a cap nut 4 that screws onto the male threaded portion 2a and pushes the water-sealing ring 3 between the fitting body 2 and the end PE of the resin pipe P, thereby pressing the water-sealing ring 3 against the end PE of the resin pipe P.

[0023] As shown in Figure 1, the inner core 1 comprises a cylindrical portion 11 that is fitted into the end PE of the resin pipe P, and a flange portion 12 provided at the base end 11a of the cylindrical portion 11 on the end face PS side of the resin pipe P. The cylindrical portion 11 is fitted into the end PE of the resin pipe P when the flange portion 12 is struck with a hammer.

[0024] The cylindrical portion 11 extends along the axial direction J of the resin pipe P from the base end 11a on the flange side 12 to the tip end 11b on the opposite side of the flange 12, with the outer diameter of the base end 11a being larger than the inner diameter of the resin pipe P, and the outer diameter of the tip end 11b being the same as or slightly smaller than the inner diameter of the resin pipe P.

[0025] Furthermore, as shown in Figure 3(a), the cylindrical portion 11 has a tapered outer surface 111 that is inclined radially outward with respect to the axial direction J at a predetermined angle θ1 from the tip portion 11b to the base portion 11a, and the tapered outer surface 111 presses the end portion PE of the resin pipe P from the inside, thereby expanding its diameter.

[0026] Furthermore, the cylindrical portion 11 is formed such that its inner circumferential surface 114 extends parallel to the axial direction J, and it becomes thinner in the radial direction from the base end 11a to the tip end 11b.

[0027] Furthermore, the cylindrical portion 11 is processed in a sawtooth cross-section from the base end 11a on the flange portion 12 side to the tip end 11b on the tapered outer surface 111, thereby forming a plurality of annular grooves 112 along the axial direction at a predetermined pitch L, each having a first inclined surface 112a that is gently inclined relative to the axial direction J and a second inclined surface 112b that is steeply inclined relative to the axial direction J. A flat surface 113 is formed at the base of the base end 11a in which the annular grooves 112 adjacent to the flange portion 12 are filled. Note that the plurality of annular grooves 112 may be provided in a manner in which they are partially interrupted along the axial direction. Also, the predetermined pitch L of the plurality of annular grooves 112 is not limited to being exactly the same pitch, but may be slightly offset.

[0028] Therefore, in the inner core 1 according to this embodiment shown in Figure 3(a), the annular groove 112 formed on the tapered outer surface 111 of the cylindrical portion 11 bites into the resin pipe P, similar to the conventional inner core 1 shown in Figure 3(b), thus more reliably preventing the resin pipe P from coming out of the inner core. Moreover, in the inner core 1 according to this embodiment shown in Figure 3(a), the flat surface 113 at the base of the cylindrical portion 11 follows the outer surface of the outermost end PE1 of the resin pipe P, filling the gap G3 (see Figure 3(b)) between the inner core 1 and the outermost end PE1 of the resin pipe P. This restricts the deformation of the end PE of the resin pipe P toward the inner core 1 when a large external force in the pulling direction is applied to the resin pipe P.

[0029] Furthermore, the cylindrical portion 11 has a flat surface 113 that is 5% to 20% of the axial length of the inner core, and in this embodiment in particular, it is formed to be 0.5 to 2 times, more preferably 1 to 2 times, the pitch L of the annular groove 112 along the axial direction. As a result, the flat surface 113 at the base of the cylindrical portion 11 is reliably aligned with the outermost end PE1 of the resin pipe P, and the gap G3 between the inner core 1 and the outermost end PE1 of the resin pipe P is reliably filled. Therefore, when a large external force is applied to the resin pipe P in the pulling direction, deformation of the end PE of the resin pipe P toward the inner core 1 can be reliably restricted.

[0030] In contrast, the cylindrical portion 11 of the conventional InCore 1, as shown in Figure 3(b), is processed in a sawtooth cross-section from the base end 11a on the flange portion 12 side to the tip end 11b on the tapered outer surface 111. This process forms multiple annular grooves 112 having a first inclined surface 112a that is gently inclined relative to the axial direction J and a second inclined surface 112b that is steeply inclined relative to the axial direction J, with a predetermined pitch L along the axial direction. However, it differs in that a flat surface 113, where the annular grooves 112 adjacent to the flange portion 12 are filled, is not formed at the base. Therefore, in the conventional InCore 1 shown in Figure 3(b), as shown in Figure 9(c), the gap G3 between the InCore 1 and the outermost end PE1 of the resin pipe P is not filled by the annular grooves 112 at the base of the cylindrical portion 11. As a result, when a large external force in the pulling direction is applied to the resin pipe P, it is not possible to restrict the deformation of the end PE of the resin pipe P toward the InCore 1.

[0031] As shown in Figure 3(a), the flange portion 12 is formed in an annular shape extending radially outward from the base end portion 11a of the cylindrical portion 11. The left side surface 121 on the opposite side (left side) of the cylindrical portion 11 is radially outward and perpendicular to the axial direction J, while the right side surface 122 on the cylindrical portion 11 side (right side) is radially outward and inclined toward the cylindrical portion 11 side (right side) at a predetermined inclination angle θ2 with respect to the radial direction perpendicular to the axial direction J of the cylindrical portion 11. The inclination angle θ2 of the right side surface 122 of the flange portion 12 is preferably in the range of 0° < θ2 ≤ 10°, and more preferably the same angle as the end face PE of the resin pipe P (in this embodiment, the same angle as the inclination angle θ1 of the tapered outer surface 111).

[0032] Therefore, in the inner core 1 shown in Figure 3(a) according to this embodiment, the right side surface 122 of the flange portion 12 easily conforms to the end surface PS of the enlarged resin pipe P, and the gap G2 between the flange portion 12 and the resin pipe P (see Figure 3(b)) is reliably filled, so that deformation of the end PE of the resin pipe P can be restricted when an external force in the pulling direction is applied to the resin pipe P. Moreover, when the inner core 1 is fitted into the end PE of the resin pipe P by driving the flange portion 12 of the inner core 1 with a hammer H, the completion of driving can be easily confirmed by visual inspection as the gap G2 between the flange portion 12 and the resin pipe P is filled, so it is possible to prevent damage to the pipe joint due to excessive driving or to continue driving unnecessarily.

[0033] In contrast, the conventional flange portion 12, as shown in Figure 3(b), is similar in that it is formed in an annular shape extending radially outward from the base end 11a of the cylindrical portion 11. However, it differs in that the right side surface 122 on the cylindrical portion 11 side (right side) extends radially outward along the radial direction perpendicular to the axial direction J of the cylindrical portion 11. As a result, a gap G2 is created between the right side surface 122 of the flange portion 12 on the cylindrical portion 11 side and the end face PS of the resin pipe P, with the gap increasing radially outward. Therefore, in the conventional flange portion 12 shown in Figure 3(b), as shown in Figure 9(c), the gap G2 between the flange portion 12 and the resin pipe P is not filled. Consequently, when an external force is applied to the resin pipe P in the pulling direction, it is not possible to restrict the deformation of the end PE of the resin pipe P, and it is difficult to visually confirm the completion of driving in the inner core 1 with the hammer H.

[0034] As shown in Figure 2, the joint body 2 comprises a first cylindrical portion 21 into which the resin pipe P is inserted, a second cylindrical portion 22 provided on the base end 21a side (left side) of the first cylindrical portion 21 to which a pipe or device other than the resin pipe P is connected, and a protruding portion 23 that protrudes radially from the outer circumferential surface.

[0035] The first cylindrical portion 21 includes an inner inner surface 211 extending along the axial direction J on the inner circumferential surface of the base end portion 21a, and a tapered inner surface 212 inclined in the opposite direction to the tapered outer surface 111 of the inner core 1 on the inner circumferential surface from the intermediate portion 21b to the tip portion 21c. Furthermore, the first cylindrical portion 21 is formed such that, from the intermediate portion 21b to the tip portion 21c, the tapered inner surface 212 extends inclined with respect to the axial direction J as described above, and the outer circumferential surface 213 extends parallel to the axial direction J, so that it becomes radially thinner from the intermediate portion 21b to the tip portion 21c. Male threaded portions 2a are formed on the outer circumferential surfaces of the intermediate portion 21b and the tip portion 21c.

[0036] The second cylindrical portion 22 extends along the axial direction J such that its outer circumferential surface 221 and inner circumferential surface 223 slightly decrease in diameter toward the left due to a constant wall thickness. At the right end, the diameter of the inner circumferential surface 223 is smaller than the inner diameter of the first cylindrical portion 21, and at the right end, the diameter of the outer circumferential surface 221 is smaller than the outer diameter of the first cylindrical portion 21. As a result, the joint body 2 has a connecting means portion 2b formed on the inner circumferential surface at the boundary between the first cylindrical portion 21 and the second cylindrical portion 22. This connecting means portion 2b functions as a stopper that restricts the entry of the resin pipe P into the second cylindrical portion 22 when the resin pipe P is inserted into the first cylindrical portion 21. The connecting means portion 2b may also have a configuration to prevent water leakage, such as a packing placed inside. The second cylindrical portion 22 has a male threaded portion 222 formed on its outer circumferential surface 221.

[0037] The projection 23 is provided around the entire circumference in the circumferential direction, straddling the outer circumferential surface 213 of the first cylindrical portion 21 and the outer circumferential surface 221 of the second cylindrical portion 22. This projection 23 functions as a stopper that restricts the entry of the cap nut 4 into the second cylindrical portion 22 side (left side) when the cap nut 4 is screwed onto the male threaded portion 2a.

[0038] As shown in Figures 2 and 4(a), the water-stopping ring 3 comprises a ring body 31 that is pressed against the end PE of the resin pipe P, and an extension 32 that extends along the axial direction J from the PS side (left side) of the end face PS of the resin pipe P on the ring body portion 31. The ring body 31 and the extension 32 have tapered outer surfaces 3a that are inclined in the same direction and contact the tapered inner surface 212 of the joint body 2.

[0039] The ring body 31 presses the resin pipe P toward the inner core 1 with an inner circumferential surface 311 extending along the axial direction J, and has an inclined surface 312 at the end opposite to the extension portion 32 (right side), and notches 313 for reducing the diameter of the ring body 31 are provided on the inclined surface 312 at predetermined intervals along the circumferential direction.

[0040] As shown in Figures 2 and 4(a), the extension 32 extends toward the end face PS side (left side) with its inner circumferential surface 321 in contact with the end PE of the resin pipe P.

[0041] Therefore, in the water-stopping ring 3 according to this embodiment shown in Figure 4(a), the extension portion 32 fills the gap G1 between the joint body 2 and the end PE of the resin pipe P. This restricts the deformation of the end PE of the resin pipe P toward the pipe joint when a large external force is applied to the resin pipe P in the pulling direction. Furthermore, even if the resin pipe P moves in the pulling direction and the outer surface of the end PE of the resin pipe P is partially scraped by the water-stopping ring 3, there is no escape route for the scraped pieces, so further scraping is suppressed. Thus, the deformation of the end PE of the resin pipe P toward the pipe joint can be sufficiently restricted.

[0042] Furthermore, the extension portion 32 is formed in a triangular cross-section that becomes thinner towards the PE side (left side) of the end face of the resin pipe P. This allows the extension portion 32 to reliably fill the gap G2 between the joint body 2 and the end PE of the resin pipe P while suppressing interference between the extension portion 32 and the joint body 2.

[0043] In contrast, conventional water-stopping rings, as shown in Figure 4(b), share the common feature of having a ring body 31, but differ in that they do not have an extension 32. Therefore, in the conventional water-stopping ring 3 shown in Figure 4(b), as shown in Figure 6, the gap G1 between the joint body 2 and the end PE of the resin pipe P is not filled because there is no extension 32. As a result, when a large external force is applied to the resin pipe P in the pulling direction, it is not possible to restrict the deformation of the end PE of the resin pipe P toward the pipe joint.

[0044] In this embodiment, as shown in Figure 5, the water-stopping ring 3 is formed such that the thickness of the end of the extension portion 32 side (left side) of the ring body 31 is smaller than the thickness of the end of the extension portion 32 on the ring body 31 side (right side). As a result, at the boundary between the ring body portion 31 and the extension portion 32, the inner circumferential surface 321 on the extension portion 32 side is larger in diameter than the inner circumferential surface 311 on the ring body portion 31 side. With this configuration, when the water-stopping ring 3 is pushed between the joint body 2 and the end PE of the resin pipe P using the cap nut 4, the stepped portion 3b of the water-stopping ring 3 bites into the end PE of the resin pipe P, thereby reliably preventing the resin pipe P from coming out of the pipe joint.

[0045] As shown in Figure 2, the cap nut 4 comprises a cylindrical nut body 41 extending along the axial direction J, and a pressing portion 42 provided on the right side of the nut body 41 and inclined to the right toward the radially inward direction. A female threaded portion 41a is formed on the inner circumferential surface that screws into the male threaded portion 2a of the joint body 2.

[0046] The pressing portion 42 is formed with an inner diameter smaller than the outer diameter of the inclined surface 312 of the water-sealing ring 3. When the male threaded portion 2a of the joint body 2 is screwed into the female threaded portion 41a of the nut body 41, the inner surface (left side) 421 presses against the inclined surface 312 of the water-sealing ring 3, thereby pushing the water-sealing ring 3 between the first cylindrical portion 21 of the joint body 2 and the end portion PE of the resin pipe P.

[0047] Thus, when the male threaded portion 2a of the joint body 2 and the female threaded portion 41a of the nut body 41 are screwed together, the gap G1 between the end PE of the resin pipe P and the water-stopping ring 3 is filled by the extension portion 32 of the water-stopping ring 3, the gap G2 between the end PE of the resin pipe P and the inner core 1 is filled by the flange portion 32 of the inner core 1, and the gap G3 of the annular groove between the outermost end PE1 of the resin pipe P and the base portion of the inner core 1 is filled. With this configuration, the gaps G1 to G3 between the end PE of the resin pipe P and the joint body 2 and inner core 1 are filled, so that when an external force in the pulling direction is applied to the resin pipe P, the deformation of the end PE of the resin pipe P is restricted, and the resin pipe P can be prevented from coming out of the pipe joint due to the deformation of the end PE of the resin pipe P.

[0048] In the above embodiment, the extension 32 is formed in a triangular cross-section that becomes thinner towards the PS side (left side) of the end face of the resin pipe P, but it may be formed in other shapes.

[0049] Furthermore, as shown in Figure 2, even if a small gap G1 occurs between the joint body 2 and the end PE of the resin pipe P between the tip of the extension 32 and the right side surface 122 of the flange 12 of the inner core 1, it is sufficient if the extension 32 extends in a way that conforms to the shape of the gap G1 and fills most of the gap G1.

[0050] Furthermore, although the water-stopping ring 3 has been described as having a stepped portion 3b at the boundary between the ring body portion 31 and the extension portion 32, it is not limited to this, and the ring body portion 31 and the extension portion 32 do not necessarily have a stepped portion at the boundary between them.

[0051] Furthermore, the extension 32 of the water-stopping ring 3, the inclined right side surface 122 of the flange 12 of the inner core 1, and the flat surface 113 of the cylindrical portion 11 of the inner core 1 are configured to fill the gaps between the end PE of the resin pipe P and the joint body 2 and inner core 1, but only one or two of these configurations may be used.

[0052] Furthermore, although the ring body 31 and extension 32 of the water-stopping ring 3 are made of the same material and are constructed in a continuous manner, they may be made of different materials.

[0053] Although embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as the present invention, or within an equivalent scope. [Explanation of Symbols]

[0054] 1…Incore 11...Cylindrical part 11a...Proximal end 11b...Tip 111... Tapered outer surface 112... Ring groove 112a...First inclined surface 112b...Second inclined surface 113…Flat surface 114…Inner peripheral surface 12... Guard part 121…Left side 122…Right side (side) 123...Outer surface 124…Inner peripheral surface 2…Fitting body 2a...Male threaded portion 2b...Connecting mechanism 21...First cylindrical part 21a...Proximal end 21b…Middle part 21c...Tip 211…Inner inner surface 212... Tapered inner surface 22...Second cylinder part 221...Outer surface 222...Male screw part 223…Inner peripheral surface 23...Protruding part 3…Water stop ring 3a... Tapered outer surface 3b...Double part 31…Ring body 311…Inner peripheral surface 312…Slope surface 313... Notch 32...Extension part 321…Inner peripheral surface 4... Cap nuts 41... Nut body 41a...Female threaded section 42...Pressing part 421...Inner surface P…Resin pipe PE...end PE1...most end PS…End face G1... Gap (the gap between the end PE of the resin pipe P and the fitting body 2) G2... Gap (the gap between the end face PS of the resin pipe P and the flange portion 12 of the inner core 1) G3... Gap (the gap between the outermost end PE1 of the resin pipe P and the annular groove at the base of the inner core 1) L...Pitch N...Length of the flat surface J…Axis direction

Claims

1. A pipe joint comprising: an inner core fitted inside the end of a resin pipe to enlarge the diameter of the end; a joint body into which the resin pipe is inserted and into which a male threaded portion is formed on the outer surface; a water-sealing ring fitted outside the resin pipe; and a cap nut that screws onto the male threaded portion of the joint body and pushes the water-sealing ring between the joint body and the end of the resin pipe, thereby pressing the water-sealing ring against the end of the resin pipe, A pipe joint characterized by having a configuration that fills the gap between the end of the resin pipe and the joint body and / or inner core.

2. The pipe joint according to claim 1, wherein the water-stopping ring has a ring body portion that is pressed against the end of the resin pipe, and an extension portion that extends axially along the end face side of the ring body portion toward the end face side of the resin pipe, the extension portion filling the gap between the joint body and the resin pipe.

3. The pipe joint according to claim 2, wherein the water-stopping ring is formed in a triangular cross-sectional shape, with the extension becoming thinner towards the end face side of the resin pipe.

4. The pipe fitting according to claim 2, wherein the water-stopping ring has a stepped portion at the boundary between the ring body and the extension portion, wherein the inner surface on the extension portion side is larger in diameter than the inner surface on the ring body side.

5. The inner core comprises a cylindrical portion having a tapered outer surface that fits inside the end of the resin tube and widens the diameter of the end, and a flange portion extending radially outward on the end face side of the resin tube. The pipe joint according to claim 1, wherein the flange portion is such that the side surface of the cylindrical portion is inclined toward the cylindrical portion with respect to the radial direction perpendicular to the axial direction of the cylindrical portion.

6. The pipe joint according to claim 5, wherein the flange portion is inclined such that the side surface on the cylindrical portion side is inclined with respect to the radial direction perpendicular to the axial direction of the cylindrical portion within a range of an inclination angle greater than 0° and less than or equal to 10° toward the cylindrical portion.

7. The inner core comprises a cylindrical portion having a tapered outer surface that fits inside the end of the resin tube and widens the diameter of the end, and a flange portion extending radially outward on the end face side of the resin tube. The pipe joint according to claim 1, wherein the cylindrical portion has a plurality of annular grooves formed along the axial direction at a predetermined pitch from the base end to the tip on the flange side of the tapered outer surface, and a flat surface is formed at the base of the base end in such a manner that the annular grooves adjacent to the flange are filled.

8. The pipe fitting according to claim 7, wherein the cylindrical portion has a flat surface that is formed to be 5% to 20% of the axial length of the inner core.

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