JP2021116867A - Joint, and piping connection structure - Google Patents

Abstract

To provide a joint that has an increased ability of holding piping.SOLUTION: A pipe joint 10 has a cylindrical core material 28 inserted into piping 14, and a lock nail 20 that includes an annular part 36 that is disposed around the outer periphery of the core material 28 and is formed of a resin material, and a metal nail 40 that is provided at the annular part 36 and is in contact with the inner periphery of the piping 14.SELECTED DRAWING: Figure 1

Description

The present invention relates to a joint and a pipe connection structure.

As a joint for connecting the pipes, there is a so-called inner surface water-stop type joint in which an annular portion having a water-stopping member and a lock claw as an exterior is inserted inside the pipe.

Japanese Unexamined Patent Publication No. 2018-35928

Patent Document 1 discloses a joint in which a lock claw is provided on the outer peripheral portion of the core material to hold the pipe from the inside of the pipe, but there is room for improvement in improving the holding performance of the pipe.

The present invention has been taken into consideration, and an object of the present invention is to provide a joint and a pipe connection structure capable of improving the holding performance of the pipe.

The joint according to claim 1 includes a tubular core material to be inserted into a pipe, an annular portion arranged on the outer peripheral portion of the core material, formed of a resin material, and in contact with the outer peripheral portion, and the annular portion. It has a metal claw which is provided in the pipe and comes into contact with the inner peripheral portion of the pipe, and a lock claw which is configured to include the claw.

In the joint according to claim 1, when the core material is inserted into the pipe, the claw of the lock claw comes into contact with the inner circumference of the pipe. Therefore, when the pipe is about to come off, the claw touches the inner circumference of the pipe. It is possible to prevent the pipe from coming off.

In order to enhance the effect of suppressing the disconnection of the pipe, it is preferable that the claw bites into the inner circumference of the pipe. There is a need.

In the joint of claim 1, since the annular portion is formed of a resin material that is more easily deformed than metal, the diameter of the annular portion is easily expanded as compared with the case where the annular portion is formed of metal, and the metal claw is formed. It becomes easier to bite into the inner circumference of the pipe, and the effect of suppressing the pipe from coming off can be enhanced.

According to the second aspect of the present invention, in the joint according to the first aspect, the lock claw is formed with a slit in the axial direction.

In the joint according to claim 2, by forming a slit in the lock claw in the axial direction, the diameter of the lock claw is easily expanded as compared with the case where the slit is not formed, and the claw is likely to bite into the inner circumference of the pipe. .. As a result, the effect of suppressing the pipe from coming off can be enhanced.

According to the third aspect of the present invention, in the joint according to the first or second aspect, a groove for accommodating the lock claw is formed on the outer peripheral portion of the core material, and the bottom surface of the groove has a groove. , A tapered inclined surface whose diameter increases toward the tip is formed on the tip side of the core material.

In the joint according to claim 3, when the pipe connected to the joint moves in the direction of coming out of the joint, the lock claw whose claw is caught in the pipe also moves in the groove together with the pipe to the tip end side of the core material. When the lock claw moves to the tip side of the core material together with the pipe and approaches the inclined surface formed on the bottom surface of the groove, the lock claw is pressed radially outward by the inclined surface, in other words, the lock claw is inclined. The surface acts to increase the diameter of the lock claw, and the lock claw is expanded in diameter.

By expanding the diameter of the lock claw, the claw bites into the inner peripheral portion of the pipe, and the effect of suppressing the pipe from coming off can be further enhanced.

The pipe connection structure according to claim 4 includes the joint according to any one of claims 1 to 3.
The pipe is provided with the pipe into which the core material is inserted, and the pipe is provided on the radial outer side of the inner peripheral surface of the pipe body and the pipe body forming the inner peripheral surface, and is more rigid than the pipe body. It is composed of an expansion suppressing layer made of a material having a high value.

The pipe connection structure according to claim 4 is configured by inserting the core material of the joint according to any one of claims 1 to 3 into the pipe.

By the way, when the lock claw expands in diameter when the pipe is about to come off, the lock claw pushes the pipe outward in the radial direction and is pushed by the lock claw to deform the pipe to the expansion side. In other words, the diameter of the pipe expands. It is conceivable to do.

Since the pipe is provided with an expansion suppression layer made of a material having a higher rigidity than the pipe body on the radial outer side of the inner peripheral surface of the pipe body forming the inner peripheral surface, it is compared with the case where there is no expansion suppression layer. As a result, the tube body is less likely to be deformed to the expansion side when pushed outward in the radial direction by the lock claw. In other words, deformation on the expansion side of the pipe can be suppressed.

In the invention according to claim 5, in the pipe connection structure according to claim 4, the expansion suppression layer is formed including a metal material, and an intermediate layer made of a resin material adheres to the outer periphery of the expansion suppression layer. A coating layer that protects the intermediate layer is provided on the outer periphery of the intermediate layer.

In the pipe connection structure according to claim 5, an intermediate layer and a coating layer are provided on the outer peripheral side of the expansion suppression layer, but the intermediate layer made of a resin material adheres to the expansion suppression layer containing a metal material. Therefore, the intermediate layer and the coating layer can be easily peeled off from the expansion suppressing layer. This facilitates the work of holding the intermediate layer and the portion from which the coating layer has been peeled off, that is, the pipe body, and inserting the core material of the joint into the pipe body.

As described above, the joint and the pipe connection structure of the present invention have an excellent effect that the holding performance of the pipe can be improved.

It is sectional drawing which shows the pipe connection structure which concerns on one Embodiment of this invention. It is a perspective view which shows the lock claw of a joint. It is a perspective view which made a part which shows the lock claw of a joint in the cross section. It is a perspective view which shows the lock claw which concerns on the modification. It is sectional drawing which shows a part of the piping which concerns on a modification. It is a perspective view which shows the piping which concerns on an example of this embodiment. It is a half cross-sectional view which shows the piping which concerns on an example of this embodiment. It is a half cross-sectional view which shows the state which the end part of the pipe which concerns on an example of this Embodiment is exposed. It is a perspective view which shows the state which the end part of the pipe which concerns on an example of this Embodiment is exposed.

A pipe connection structure 12 provided with a pipe joint 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the pipe connection structure 12 of the present embodiment includes a pipe joint 10 and a pipe 14.
The pipe joint 10 and the pipe 14 of the present embodiment can be suitably used for water supply and hot water supply as an example, but can also be used for any fluid including liquid or gas other than water. What you get.

The pipe joint 10 includes a joint body 16, a water blocking member 18, and a lock claw 20.
The pipe joint 10 is formed in a straight line and has a symmetrical shape with the central portion in the longitudinal direction interposed therebetween, but may have a left-right paired non-named shape, for example, a substantially L-shape, a substantially T-shape, or a substantially cross shape. Etc., it may be configured in any shape.

The joint body 16 of the present embodiment has a pipe shape formed in a straight line, and a flow path 22 penetrates through the axial center portion.
A flange 24 is formed at the center of the joint body 16 in the longitudinal direction so as to project outward in the radial direction.

The joint body 16 is formed with core members 28 to be inserted into the pipe 14 on both sides of the flange 24.

A first groove 30 for accommodating a water blocking member 18 such as an O-ring made of an elastic body is formed on the outer periphery of the core material 28, and a first groove 30 is formed on the flange 24 side of the first groove 30. A second groove 32 is formed in which the lock claw 20 described later is housed.

The groove bottom of the first groove 30 is formed to have a constant diameter in the axial direction.
On the other hand, the second groove 32 is formed to have a longer axial length than the annular portion 36 of the lock claw 20 described later. A constant diameter portion 32A having a constant diameter is formed on the groove bottom of the second groove 32, and the tip side of the core material 28 (opposite to the flange 24) is the tip side of the core material 28. A tapered inclined surface 32B whose diameter of the groove bottom increases toward the surface is formed.

A stopper 34 is provided between the core material 28 and the flange 24, which is formed to have a diameter larger than that of the core material 28 and abuts the end portion of the pipe 14.

(Lock claw)
Next, the configuration of the lock claw 20 will be described.
As shown in FIGS. 2A and 2B, the lock claw 20 of the present embodiment has a substantially C-shape as a whole, in other words, is not continuous in the circumferential direction. It is formed in a ring shape. By making the entire shape of the lock claw 20 substantially C-shaped, elastic deformation (diameter expansion and diameter reduction) in the radial direction is facilitated. Therefore, when the core material 28 is accommodated in the second groove 32, the diameter is increased so that the inner diameter is larger than the diameter of the core material 28, and the core material 28 can be easily accommodated in the second groove 32.

The lock claw 20 includes a resin annular portion 36 formed in a substantially C shape.
In the annular portion 36, slits 38 extending along the axis toward the opposite end portion are spaced apart from each other in the circumferential direction at the end portion on the core material tip side (direction of arrow F in the drawing) when mounted on the core material 28. It is opened and formed at a plurality of locations (five locations in the present embodiment).

A metal claw 40 projects from the outer peripheral portion of the annular portion 36 between the slit 38 and the slit 38 and between the slit 38 and the circumferential end portion 36E of the annular portion 36. The claws 40 are independently and integrally embedded in the resin of the annular portion 36, and a part thereof protrudes from the outer peripheral portion of the annular portion 36. As an example, the claw 40 can be formed by press-molding a metal plate or the like. Further, the claw 40 can be integrated with the resin material when the annular portion 36 is molded using the resin material.

Hereinafter, in the present specification, the portion of the claw 40 that protrudes from the outer peripheral portion of the annular portion 36 is referred to as a bite portion 40A.
The bite portion 40A is inclined with respect to the radial direction of the annular portion 36 in a direction opposite to the tip end side of the core material 28, in other words, in a direction in which the pipe 14 is inserted into the core material 28.

As an example, the outer diameter of the annular portion 36 is determined so that the lock claw 20 does not protrude from the outer surface of the core material 28 when the lock claw 20 is housed in the second groove 32 of the core material 28. When the lock claw 20 is housed in the second groove 32, the annular portion 36 comes into contact with the bottom surface of the second groove 32 (the outer peripheral portion of the core material 28).

On the other hand, as shown in FIG. 3, the diameter φ of the virtual circle FC passing through the tip of each biting portion 40A is measured in a state where the lock claw 20 is accommodated in the second groove 32, and the diameter φ is outside the core material 28. The outer diameter is set to be larger than the diameter D (see FIG. 1) and to come into contact with the inner peripheral portion of the pipe 14.

(Plumbing)
The pipe 14 used in the pipe connection structure 12 of the present embodiment is a composite pipe having a multi-layer structure.
The pipe 14 includes a pipe body 42, a corrugated pipe 44 as a covering layer, an intermediate layer 46, and an expansion suppression layer 48.

The tube body 42 is a resin tube formed by using a resin material and having a cylindrical tubular shape. The tube body 42 is arranged inside the corrugated tube 44. Examples of the resin as the resin material include polyolefins such as polybutene, polyethylene, cross-linked polyethylene, polypropylene, vinyl chloride and the like. Only one type of resin may be used, or two or more types may be used in combination. Among the resins, polybutene is preferably used, and it is preferable that polybutene is contained as a main component.

An expansion suppressing layer 48 is provided in close contact with the outside of the tubular body 42. As an example, the expansion suppressing layer 48 can be a layer containing a metal material having a higher rigidity (as an example, tensile rigidity) than the resin constituting the pipe body 42. More specifically, as the expansion suppressing layer 48, a mesh-like layer or the like in which metal fibers are woven can be used.
The expansion suppression layer 48 may be integrated with the outer peripheral surface of the pipe body 42, or may be embedded in an intermediate portion in the thickness direction of the pipe body 42 as shown in FIG.

The corrugated pipe 44 has a cylindrical tubular shape that is one size larger than the outer diameter of the pipe body 42, and is arranged in the pipe body 42 with an intermediate layer 46 interposed therebetween. The corrugated tube 44 is a resin tube formed by using a resin material. Examples of the resin as the resin material include polyolefins such as polybutene, polyethylene, polypropylene, and cross-linked polyethylene, vinyl chloride, and the like. Only one type of resin may be used, or two or more types may be used in combination.

The corrugated pipe 44 alternately has an annular peak portion 44A that is convex outward in the radial direction R and an annular valley portion 44B that is concave outside in the radial direction R along the axial direction S of the pipe body 42. It is formed continuously. That is, the corrugated tube 44 is formed in a bellows shape and can be shortened in the axial direction.

The intermediate layer 46 has a sheet shape and is arranged between the pipe body 42 and the corrugated pipe 44. The inner peripheral surface of the intermediate layer 46 is made flat and covers the outer circumference of the pipe body 42 while being in full contact with the outer circumference of the pipe body 42. In addition, "total contact" here means that not all parts need to be in close contact with each other, but substantially the entire surface is in contact. Therefore, the case where the joint portion of the sheet-shaped intermediate layer 46 is partially separated, or the wrinkled portion between the pipe body 42 and the corrugated pipe 44 is partially separated is included.

Examples of the resin as the intermediate layer 46 include polyurethane, polystyrene, polyethylene, polypropylene, and ethylene propylene diene rubber, and a mixture of these resins. Among the resins, polyurethane is preferable. The intermediate layer 46 is preferably a layer containing polyurethane as a main component (that is, a porous urethane layer). For example, in the constituent components of the intermediate layer 46, it is preferable that polyurethane is contained in an amount of 80% by mass or more, and more preferably 90% by mass or more. The porous resin layer as the intermediate layer 46 may contain other additives.

(Action, effect)
Next, the actions and effects of this embodiment will be described.
As an example, the pipe joint 10 of the present embodiment is connected to the pipe 14 by inserting the core material 28 into the pipe 14, as shown in FIG.

Before inserting the core material 28 into the pipe 14, it is preferable to remove a part of the corrugated pipe 44 and the intermediate layer 46 on the tip side of the pipe 14. By grasping the portion from which the corrugated pipe 44 and the intermediate layer 46 have been removed, that is, the pipe body 42 provided with the expansion suppression layer 48, the pipe body 42 is held and the core material 28 of the pipe joint 10 is attached to the pipe body 42. The work of inserting becomes easier. Since the intermediate layer 46 is only attached to the expansion suppression layer 48, the intermediate layer 46 can be easily peeled off from the expansion suppression layer 48.

The pipe joint 10 of the present embodiment simplifies the connection work between the pipe 14 and the pipe joint 10 by inserting the core material 28 into the pipe 14 until the end of the pipe 14 hits the stopper 34 of the core material 28. Can be terminated to.

In the state where the core material 28 is inserted into the pipe 14, the water blocking member 18 is in close contact with the inner peripheral portion of the pipe 14 to stop water, and the inner peripheral portion of the annular portion 36 of the lock claw 20 is the second. It is in contact with the bottom surface of the groove 32, and the biting portion 40A of the claw 40 is in contact with the inner peripheral portion of the pipe 14.

In the pipe joint 10 of the present embodiment, when the pipe 14 is about to come off, the tip of the bite portion 40A is caught on the inner circumference of the pipe 14, so that the pipe 14 can be suppressed from coming off. By allowing the tip of the biting portion 40A to bite into the inner surface of the pipe 14, the effect of suppressing the disconnection of the pipe 14 can be further enhanced.

In order to enhance the effect of suppressing the disconnection of the pipe 14, it is preferable that the tip of the biting portion 40A bites into the inner circumference of the pipe 14, but to make the tip of the biting portion 40A bite into the pipe 14, the lock claw 20 is used. It is necessary to increase the diameter.

In the pipe joint 10 of the present embodiment, when a large force is applied to the pipe 14 connected to the pipe joint 10 in the direction of pulling out from the pipe joint 10, the claw 40 is caught on the inner peripheral surface of the pipe 14. The lock claw 20 also moves together with the pipe 14 in the second groove 32 toward the tip end side of the joint body 16.

When the lock claw 20 moves to the tip end side of the joint body 16 together with the pipe 14 and slides on the inclined surface 32B formed on the bottom surface of the second groove 32, the lock claw 20 is pressed outward in the radial direction by the inclined surface 32B. In other words, a force for expanding the diameter of the lock claw 20 acts on the lock claw 20 by the inclined surface 32B, and the lock claw 20 is expanded in diameter.

By expanding the diameter of the lock claw 20, the claw 40 bites into the inner peripheral portion of the pipe body 42, and the effect of suppressing the pipe 14 from coming off can be further enhanced.

In the lock claw 20 of the present embodiment, the annular portion 36 is formed of a resin material that is more easily deformed than metal. Therefore, when the annular portion 36 is formed of metal, in other words, the entire lock claw is formed of metal. Compared to the case where the diameter is increased, the diameter of the metal claw 40 is easily increased, and the biting portion 40A of the metal claw 40 is easily bitten into the inner circumference of the pipe 14. Therefore, the lock claw 20 of the present embodiment has an effect of suppressing the pipe 14 from coming off, in other words, the holding performance of the pipe 14 is improved.

Further, in the lock claw 20 of the present embodiment, since the shape of the annular portion 36 is C-shaped and a plurality of slits 38 extending in the axial direction are formed, the lock claw 20 is continuously formed in an annular shape in the circumferential direction. Compared with the case, the diameter is easily expanded, and the biting portion 40A is more easily bitten into the inner circumference of the pipe 14.

By the way, when the diameter of the lock claw 20 is expanded when the pipe 14 is about to come off, the pipe 14 is pushed outward in the radial direction by the lock claw 20, and is pushed by the lock claw 20 to deform the pipe to the expansion side, in other words. , It is conceivable that the diameter of the pipe 14 is increased.

The pipe 14 used in the pipe connection structure 12 of the present embodiment is a material having a higher rigidity than the resin material constituting the pipe body 42 on the outer peripheral side of the inner peripheral surface of the pipe body 42 forming the inner peripheral surface. Since the expansion suppression layer 48 is provided, it is less likely to be deformed to the expansion side when pushed outward in the radial direction by the lock claw 20 as compared with the case where the expansion suppression layer 48 is not provided. In other words, deformation of the expansion side of the pipe 14 can be suppressed.

Therefore, it is not necessary to provide a metal cylindrical cover on the outer peripheral side of the pipe 14 to suppress deformation on the expansion side of the pipe 14, and a slimmer pipe connection structure can be obtained as compared with the case where the cover is provided. realizable. Further, when connecting the pipe 14 to the pipe joint 10, it is not necessary to attach a cover, which facilitates the connection work.

[Other Embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be variously modified and implemented within a range not deviating from the gist thereof. Is.

The lock claw 20 of the above embodiment is formed in a C shape and is not continuously formed in the circumferential direction, but as shown in FIG. 4, it has an annular shape and is continuously connected in the circumferential direction. It may be. In the lock claw 20 shown in FIG. 4, a slit 38A formed from one end side in the axial direction toward the other end side and a slit 38B formed from the other end side in the axial direction toward one end side are formed in the circumferential direction. It is formed alternately and is continuous in the circumferential direction, but like the lock claw 20, it is easy to expand and contract in the radial direction.

Hereinafter, an example of the structure of the pipe 14 described in the above embodiment will be described in detail with reference to FIGS. 6 to 9.

As shown in FIGS. 6 and 7, the corrugated tube 44 has an annular peak portion 44A which is tubular and is convex outward in the radial direction and an annular valley portion 44B which is concave outward in the radial direction in the axial direction. It is formed alternately (in the direction of the axis S), for example, continuously to form a bellows shape, and can be shortened in the axial direction at the peak portion 44A and the valley portion 44B. The corrugated pipe 44 has a cylindrical tubular shape that is one size larger than the outer diameter of the pipe body 42, and is arranged in the pipe body 42 with an intermediate layer 46 interposed therebetween.

The intermediate layer 46 is arranged inside the corrugated pipe 44, specifically between the pipe body 42 and the corrugated pipe 44, and is made of, for example, a foamed resin. The inner peripheral surface of the intermediate layer 46 is made flat and covers the outer circumference of the pipe body 42 while being in full contact with the outer circumference of the pipe body 42.
In addition, as described above, "total contact" here means that not all parts need to be in close contact with each other, but substantially the entire surface is in contact. Therefore, the case where a part of the intermediate layer 46 is separated from the tube body 42 is included. Further, the intermediate layer 46 does not have to be made of a foamed resin.

The intermediate layer 46 is made of a material having a melting point lower than that of the material of the expansion suppressing layer 48 of the tubular body 42. The expansion suppression layer 48 is an example of the outer peripheral surface of the tubular body 42. Examples of the resin as the intermediate layer 46 include polyurethane, polystyrene, polyethylene, polypropylene, and ethylene propylene diene rubber, and a mixture of these resins. Among the resins, polyurethane is preferable. The intermediate layer 46 is preferably a layer containing polyurethane as a main component (that is, a porous urethane layer). For example, in the constituent components of the intermediate layer 46, it is preferable that polyurethane is contained in an amount of 80% by mass or more, and more preferably 90% by mass or more. The porous resin layer as the intermediate layer 46 may contain other additives.

The tubular body 42 is arranged inside the intermediate layer 46, and its outer peripheral surface is made of a material that does not easily adhere to the intermediate layer 46. The tubular body 42 has a cylindrical tubular shape and at least a two-layer structure. In the illustrated example, the tubular body 42 has a two-layer structure of an expansion suppression layer 48 and an inner layer 50. The expansion suppression layer 48 is provided in close contact with the outside of the inner layer 50. As an example, the expansion suppression layer 48 constituting the outer peripheral surface of the tubular body 42 can be a layer containing a metal material having a higher tensile rigidity than the resin constituting the tubular body 42. As an example, the expansion suppression layer 48 is made of a metal such as aluminum or copper. In order to form the expansion suppression layer 48 on the outside of the tubular body 42, for example, a metal sheet may be wound around the outer periphery of the inner layer 50, or the inner layer 50 may be inserted inside the metal tube.

The inner layer 50 is formed by using, for example, a resin material. Examples of the resin as the resin material include polyolefins such as polybutene, polyethylene, cross-linked polyethylene, polypropylene, vinyl chloride and the like. Only one type of resin may be used, or two or more types may be used in combination. Among the resins, polybutene is preferably used, and it is preferable that polybutene is contained as a main component.

The outer peripheral surface of the tubular body 42, that is, the expansion suppression layer 48 may be made of fluororesin. Since the material constituting the outer peripheral surface of the tubular body 42 may be a material that does not easily adhere to the intermediate layer 46, not all of the inner layer 50 is covered with the expansion suppression layer 48, and a part of the inner layer 50 is It may be exposed on the outer peripheral surface of the tubular body 42. Further, on the outer peripheral surface of the tubular body 42, a shape capable of suppressing adhesion to the intermediate layer 46, for example, a scratch-like thin streak (not shown) extending in the axial direction may be formed. That is, the structure may be such that the adhesion between the outer peripheral surface of the tubular body 42 and the intermediate layer 46 can be suppressed as compared with the case where the resin material is completely exposed on the outer peripheral surface of the tubular body 42.

Further, the inner layer 50 may be composed of a plurality of layers. Further, at least a part of the inner layer 50 may be constructed of a metal such as copper. That is, the tubular body 42 may be composed of three or more layers including the expansion suppressing layer 48.

(Action, effect)

Also in the present embodiment, before inserting the core material 28 into the pipe 14, as shown in FIGS. 8 and 9, a part of the corrugated pipe 44 on the tip side of the pipe 14 and the intermediate layer 46 are peeled off to form a pipe. It is preferable to expose the body 42. By gripping the exposed pipe body 42, it becomes easy to hold the pipe body 42 and insert the core material 28 of the pipe joint 10 into the pipe body 42.

In the pipe 14 according to the present embodiment, the outer peripheral surface of the pipe body 42 is made of a material that does not easily adhere to the intermediate layer 46. Specifically, the pipe body 42 has at least a two-layer structure, and the expansion suppression layer 48 forming the outer peripheral surface of the pipe body 42 is made of metal. Further, the intermediate layer 46 is made of a material having a melting point lower than that of the material of the outer peripheral surface of the pipe body 42. Therefore, the melting point of the outer peripheral surface is higher than the temperature at which the resin is melted and foamed on the outside of the tubular body 42 by extrusion molding to form the intermediate layer 46. Therefore, even if the resin is melted and foamed on the outside of the tubular body 42 by extrusion molding to form the intermediate layer 46, the outer peripheral surface of the tubular body 42 does not melt, so that the intermediate layer 46 adheres to the outer peripheral surface of the tubular body 42. It's hard to do. As a result, adhesion between the intermediate layer 46 and the outer peripheral surface of the pipe body 42 at the time of manufacturing the pipe 14 can be suppressed.

Therefore, when the pipe 14 is connected to the pipe joint 10, the corrugated pipe 44 and the intermediate layer 46 can be easily contracted in the axial direction of the pipe body 42 and peeled off from the pipe body 42.

Further, at the time of manufacturing the pipe 14, the step of cooling the foam-molded intermediate layer 46 and then inserting the inner layer into the intermediate layer 46 becomes unnecessary. Therefore, the pipe 14 in which the corrugated pipe 44 and the intermediate layer 46 can be easily peeled off from the pipe body 42 can be manufactured on one production line.

Further, since the pipe body 42 has at least a two-layer structure, the material of the inner layer that does not form the outer peripheral surface of the pipe body 42 can be freely selected to some extent, and the intermediate layer 46 and the outer peripheral surface of the pipe body 42 can be separated from each other. Adhesion can be suppressed.

When the outer peripheral surface of the tubular body 42 is made of fluororesin, the outer peripheral surface is slippery, so that adhesion between the intermediate layer 46 and the outer peripheral surface of the tubular body 42 can be suppressed. Further, when the pipe 14 is connected to the pipe joint 10, the corrugated pipe 44 and the intermediate layer 46 are easily peeled off from the pipe body 42 to expose the pipe body 42.

10 ... Pipe fitting, 12 ... Pipe connection structure, 14 ... Piping, 16 ... Joint body, 20 ... Lock claw, 32 ... Second groove, 32 ... Inclined surface, 36 ... Ring part, 38 ... Slit, 40 ... Claw, 42 ... tube body, 48 ... expansion suppression layer, 46 ... intermediate layer, 44 ... corrugated tube (coating layer)

Claims (5)

A tubular core material to be inserted into the pipe and
It is composed of an annular portion arranged on the outer peripheral portion of the core material and formed of a resin material and in contact with the outer peripheral portion, and a metal claw provided on the annular portion and in contact with the inner peripheral portion of the pipe. Locked claws and
Fittings with. The joint according to claim 1, wherein the lock claw has a slit formed in the axial direction. A groove for accommodating the lock claw is formed on the outer peripheral portion of the core material.
On the bottom surface of the groove, a tapered inclined surface whose diameter increases toward the tip is formed on the tip side of the core material.
The joint according to claim 1 or 2. The joint according to any one of claims 1 to 3.
The pipe into which the core material is inserted and
With
The pipe is configured to include a pipe body forming an inner peripheral surface and an expansion suppression layer made of a material provided radially outside the inner peripheral surface of the pipe body and having a higher rigidity than the pipe body. The piping connection structure. The expansion suppression layer is formed by including a metal material, and is formed.
An intermediate layer made of a resin material is attached to the outer periphery of the expansion suppression layer.
A coating layer that protects the intermediate layer is provided on the outer periphery of the intermediate layer.
The pipe connection structure according to claim 4.

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