WO2021010293A1

WO2021010293A1 - Pipe fitting

Info

Publication number: WO2021010293A1
Application number: PCT/JP2020/026915
Authority: WO
Inventors: 啓治依田; 大松高根澤
Original assignee: 株式会社潤工社
Priority date: 2019-07-12
Filing date: 2020-07-09
Publication date: 2021-01-21

Abstract

The present invention relates to a pipe fitting to which a pipe body is connected, and which can be used repeatedly without leakage and without the pipe body coming out. This pipe fitting is provided with a fitting main body having a hollow portion into which a pipe body can be inserted, a gripper inside the fitting main body for gripping the outer circumference of the pipe body, and a sealing ring for filling a gap between the hollow portion and the pipe body, wherein: the gripper is provided with an annular portion, and a plurality of claw portions which extend inward from the annular portion, obliquely in the pipe body insertion direction; if α1 (degrees) is the angle between the claw portions and the outer circumferential surface of the pipe body when the pipe body has been inserted into the hollow portion, α1 is greater than 40 and at most equal to 70; if α2 is the angle between the claw portions and the outer circumferential surface of the pipe body when a 50 N pulling-out stress is applied to the pipe body, the relational expression -2≤α2-α1<35 is satisfied; and in a state in which the pipe body has been inserted into the hollow portion, the claw portions bite into the pipe body by an amount that is at least equal to 3% and less than 35% of the thickness of the pipe body.

Description

Pipe fitting

The present invention relates to a plug-in type joint to which a resin pipe body is connected.

Conventionally, a plug-in type joint capable of connecting a joint and a pipe body by simply inserting the pipe body into the joint has been known. Since the pipe body can be attached without using a tool, the pipe body connection work is easy, and it is widely used for piping in a narrow space where it is inconvenient to use a tool. In this type of joint, it is essential that the pipe body is easy to insert, that it is securely attached, and that the pipe body is not pulled out during use or that internal fluid does not leak.

Such a plug-in type joint has a structure in which the pipe body is held so as not to come off by a gripper built in the joint body, and internal pressure is applied to the pipe body inserted into the joint body so that the pipe body is pulled out. When displaced, the gripper bites in and locks the tube. For example, in Japanese Patent Application Laid-Open No. 2004-232720, in response to the problem that the initial biting force of the lock ring and the pull-out strength when the tube is strongly pulled vary in the plug-in type joint, the initial biting force with the pipe inserted is solved. A pipe joint is disclosed in which the angle between the lower surface of the lock ring and the surface of the pipe is 20 to 40 degrees (see Patent Document 1). However, with these conventional plug-in type joints, the use of these conventional plug-in type joints has been restricted because the pipe body may come off or leak depending on the usage conditions.

Japanese Unexamined Patent Publication No. 2004-232720

The present invention has been made in view of the above problems, and an object of the present invention is to provide a plug-in type pipe joint in which pipe body omission and fluid leakage are unlikely to occur even under conditions where conventional use has been restricted. is there.

In view of the above problems, the present inventors have arrived at the present invention as a result of diligent studies on a pipe joint to which a pipe body that is less likely to come off or leak fluid is connected.

That is, in order to achieve the above object, the joint of the present invention includes a joint body into which a pipe body can be inserted into a hollow portion, a gripping tool inside the joint body that grips the outer periphery of the pipe body, and the hollow portion. A joint including a seal ring that fills a gap with the tubular body, wherein the gripping tool includes an annular portion and a plurality of claw portions extending inward from the annular portion and diagonally in the insertion direction of the tubular body. It is equipped with
When the angle of the claw portion with respect to the central axis of the tube body when the tube body is inserted into the hollow portion is α1 (degree), α1 is larger than 40 and 70 or less, and 50 N is drawn into the tube body. Assuming that the angle of the claw portion with respect to the central axis of the tube body when a load is applied is α2 (degrees), the claw is satisfied with the following formula (1) and the tube body is inserted into the hollow portion. The amount of the portion biting into the tube is characterized by being 3% or more and less than 35% of the thickness of the tube.
-2 ≤ α2-α1 <35 (1)

The angle α1 (degree) of the claw portion with respect to the tube center axis and the angle α2 (degree) of the claw portion with respect to the tube body center axis satisfy the following formula (2), and the tube is formed in the hollow portion. It is more preferable that the amount of the claw portion biting into the tube body with the body inserted is 3% or more and less than 28% of the thickness of the tube body.
-2 ≤ α 2-α 1 ≤ 25 (2)
Further, the angle α1 (degree) of the claw portion with respect to the tube center axis and the angle α2 (degree) of the claw portion with respect to the tube body center axis satisfy the following formula (3), and the hollow portion has a hollow portion. It is more preferable that the amount of the claw portion biting into the tube body with the tube body inserted is 3% or more and less than 15% of the thickness of the tube body.
-2 ≤ α 2-α 1 ≤ 10 (3)

It is more preferable that the hardness of the pipe body connected to the joint of the present invention is HDD60 or more as measured in accordance with JIS K7215.

It is a figure explaining one Embodiment of the pipe fitting of this invention. It is a figure explaining an example of the structure of the gripping tool for a pipe joint of this invention, (A) is a plan view, (B) is a cross-sectional view of AA'. It is a figure explaining the shape of the gripper. It is a figure which shows the relationship between the gripper of the plug-in type pipe joint of this invention, and a pipe body. It is an enlarged image figure of the contact part of a gripper and a tube body. It is a figure explaining the biting depth into the tube body of the claw part of a gripper. In the plug-in type pipe joint of the present invention, it is a figure which shows the displacement amount of the angle with respect to the pipe body central axis of the claw part of the gripping tool, and the pressure resistance.

FIG. 1 is a partial cross-sectional side view showing an embodiment of a pipe joint of the present invention. The configuration of the plug-in pipe joint of the present invention will be described by taking the embodiment of FIG. 1 as an example.

The pipe joint 1 to which the pipe body shown in the embodiment of FIG. 1 is connected has a joint body 110 into which the pipe body can be inserted into a hollow portion and a pipe in the joint body that contacts the outer periphery of the pipe body 2. It includes a gripping tool 120 for gripping the body, a seal ring 130 for filling the gap between the joint body 110 and the pipe body 2, and a pressing ring 140 for holding the gripping tool 120 and the seal ring 130 inside the joint body 110. Depending on the shape of the joint body, the holding ring 140 may not be provided. In the present invention, the direction of arrow I is the insertion direction, and the direction of arrow R is the pull-out direction.

The joint body 110 has a tubular shape, and on the inner wall surface thereof, in order from the back side in the pipe body insertion direction, a bottom portion 111a of the pipe body insertion portion of the hollow portion, a step portion 111b for locking the seal ring 130, and a gripper 120 are provided. A step portion 111c for locking and a step portion 111d for locking the presser ring 140 are provided. The material of the joint body 110 is preferably a metal such as stainless steel or brass.

FIG. 2 is an example of the gripping tool 120 for the plug-in type pipe joint of the present invention of FIG. 1, and is a diagram for explaining the structure thereof. 2 (A) is a plan view, and FIG. 2 (B) is a cross-sectional view taken along the line AA'of FIG. 2 (A). The gripper 120 includes an annular portion 121 and a plurality of claw portions 122 extending inward from the annular portion and in the oblique tube insertion direction. The claw portion 122 is composed of a claw body portion 122a and a claw tip portion 122b, and the claw tip 122b contacts the tubular body to grip the tubular body. Although FIG. 2 shows an example in which the claw portion is composed of three claws, the number of claws may be three or more, such as three or five. FIG. 3 is a diagram illustrating an angle between the annular portion 121 and the claw portion 122 of the gripper 120. In the gripping tool 120 for a plug-in type pipe joint of the present invention, the angle θ (degree) between the annular portion 121 and the claw portion 122 is preferably in the range of 20 to 50, more preferably 25 to 40, and 25. It is more preferably from to 35.

FIG. 4 is a diagram showing the relationship between the gripping tool 120 in a state where the pipe body 2 is inserted into the joint body and the pipe body 2 in the plug-in type pipe joint of the present invention, and the joint 1 in the state where the pipe body 2 is inserted is shown. It represents the mutual positional relationship between the gripper and the tubular body in the cross section when cut along the surface along the central axis of the tubular body 2. Here, the "angle of the claw with respect to the central axis of the tube" is an angle between the center axis B of the tube 2 and the center line C of the claw 122 of the gripper 120, which is referred to as the claw. The angle α (degrees) with respect to the central axis of the tube. The angle α (degrees) when the pipe body is inserted into the hollow portion of the joint body is α1 (degrees), and the angle α (degrees) when a pull-out load of 50 N is applied to the pipe body is α2 (degrees). To do. The state of "when the pipe body is inserted into the hollow portion of the joint body" refers to the state after inserting the pipe body into the joint and before pressurizing the inside of the pipe body or applying a pull-out load to the pipe body.

In the conventional plug-in type joint, when the pipe body is inserted into the hollow part of the joint body, the claw part of the gripper is relative to the pipe body central axis as compared with the state before the pipe body is inserted into the joint. It is inclined in the direction of inserting the tube. After that, when the inside of the tube is pressurized, a force in the pulling direction acts on the tube to displace the tube in the pulling direction, and the tip of the claw of the gripper follows the tube and of the tube. Displace in the pull-out direction. In the conventional plug-in type joint, the angle α ₁ (degree) of the claw part of the gripping tool with respect to the tube center axis and the angle α ₂ (degree) of the claw part with respect to the tube body center axis change more than 35, and the gripping tool The claws are designed to bite into the tube.

The plug-in type joint of the present invention has a state before the pipe body is inserted into the hollow part of the joint body and a state when the pipe body is inserted into the hollow part of the joint body. The change in the angle with respect to the shaft is small, and the angle α ₁ (degree) of the claw portion with respect to the central axis of the pipe body when the pipe body is inserted into the hollow portion of the joint body is in the range of more than 40 and 70 or less. The angle α ₁ (degree) of the claw portion with respect to the central axis of the tube is more preferably in the range of more than 50 and 65 or less, and further preferably in the range of more than 55 and 65 or less. After that, even when the inside of the tube is pressurized and a force in the pulling direction is applied to the tube, the change in the mutual position of the gripper with respect to the central axis of the tube is small, and the gripper's claw is small. The change in the angle α ₁ (degree) with respect to the central axis of the tube and the angle α ₂ (degree) of the claw with respect to the central axis of the tube is less than 35. The amount of the gripper's claw biting into the tube is 3% or more and less than 35% of the thickness of the tube from the time the tube is inserted into the hollow part to the time when a pull-out load of 50 N is applied to the tube. The change in the angle α ₁ (degree) of the claw part of the gripping tool with respect to the central axis of the tube body and the angle α ₂ (degree) of the claw part with respect to the central axis of the tube body is smaller than 35, so that the tube of the gripping tool is maintained. Excessive bite into the body is suppressed. For example, the bite of the gripper into the tube is suppressed to less than 35% of the thickness of the tube.

The material of the gripping tool for the plug-in type joint of the present invention is preferably made of a metal having high mechanical strength and elasticity. For example, stainless steel, phosphor bronze, beryllium steel, nickel-tin steel and the like are suitable, and these metal plates can be punched and formed. Further, the gripping tool is preferably designed so that the crushing resistance of the gripping tool is 15N to 25N. The crushing resistance of the gripping tool is mainly determined by the material used for the gripping tool, the wall thickness, and the angle θ between the annular part and the claw part of the gripping tool. If the crushing resistance strength is small, the claw part and the outer peripheral surface of the pipe body The angle α ₁ between them tends to be large, and if the crushing resistance is too large, there is a high possibility that adverse effects such as damage to the pipe body will occur. The crushing resistance of the gripper is measured as follows. Place it on a flat surface so that the tip of the claw of the gripper is on the lower side, and press a block large enough to cover the annular part of the gripper against the gripper and compress it at a speed of 5 mm / min to reduce the amount of pushing. The load when it reaches 0.5 mm is defined as the crushing resistance of the gripper.

FIG. 5 shows the vicinity of the contact portion between the gripper and the pipe body in the cross section of the plug-in type joint of the present invention when the joint with the pipe body 2 inserted is cut along the surface along the central axis of the pipe body 2. It is an enlarged image diagram. The claw portion 122 of the gripping tool for a plug-in type joint of the present invention has a continuous and stepwise reduction in cross-sectional area toward the tip of the claw portion. The angle θ1 between the surface 123a of the tip portion 122b of the nail facing the tube insertion direction and the surface of the tube is preferably 60 degrees or less, and more preferably 45 degrees or less. The tip of the claw that comes into contact with the tube is preferably multifaceted with an angle of 90 degrees or more. For example, in the example shown in FIG. 5, the angle θ2 between the surface 123a on the tube insertion port side of the tip of the nail and the second surface 123b of the tip of the nail is 110 degrees.

The seal ring 130 of the plug-in type joint of the present invention is arranged at the step portion 111b of the joint body 110, and when the pipe body is inserted, it comes into contact with the inner wall surface of the joint body 110 and the outer peripheral surface of the pipe body, and is airtight (liquid). Arranged to maintain sex. The seal ring may have an O-ring having a circular cross section or another shape such as a U-shaped cross section. The seal ring 130 is in contact with the claw portion of the gripping tool 120, and supports the action of the gripping tool 120 to grip the pipe body.

As described above, the plug-in type joint of the present invention has an angle α ₁ (degree) of the claw portion of the gripping tool with respect to the central axis of the pipe body when the pipe body is inserted into the joint, and pulling out 50 N into the pipe body. The relationship of the angle α ₂ (degrees) of the claw portion with respect to the central axis of the tube when a load is applied is preferably in the range satisfying the equation −2 ≦ α2-α1 <35. The relationship between the angle α ₁ (degrees) of the claws with respect to the central axis of the tube and the angle α ₂ (degrees) of the claws with respect to the central axis of the tube when a pull-out load of 50 N is applied to the tube is as follows. It is more preferable that the range satisfies the equation of -2≤α2-α1≤25, and further preferably the range satisfies the equation of -2≤α2-α1≤10. The plug-in type joint of the present invention in which the relationship between α ₁ (degree) and α ₂ (degree) is within the above range is the tip of the claw of the gripper when a pull-out load is applied to the pipe body due to high pressure or the like. The displacement of the pipe is small, and the force for gripping the pipe body can be stably obtained.

It is preferable that the plug-in type joint of the present invention is used by joining a tubular body having a hardness of HDD60 or more measured in accordance with JIS K7215. When a tube body of HDD 60 or more is joined and used, the function of the joint of the present invention can be obtained more effectively.

The presser ring 140 used in the embodiment shown in FIG. 1 of the plug-in type joint of the present invention is arranged so that the movement is restricted by the step portion 111d of the joint main body 110. The annular portion of the grip 120 is restricted in movement between the presser ring 140 and the stepped portion 111c of the joint body 110. The presser ring 140 is preferably made of a metal such as stainless steel or brass so that the joint and the pipe body are not deformed even when a high pressure or a pull-out load is applied.

It is preferable that the pipe joint of the present invention further includes a release sleeve 150 that releases the gripper from biting into the pipe body. The release sleeve 150 is preferably formed of a metal such as stainless steel or brass or a resin having a high hardness so that the joint and the pipe body are not deformed even when a high pressure or a pull-out load is applied.

[Measuring method]
Various measurements are performed as follows.
<Measurement of the angle of the grip claw with respect to the central axis of the tube>
Insert a tube cut to a length of about 100 mm into the joint. Epoxy resin is poured into the inside of the pipe and the joint to cure it without applying pressure to the inside of the pipe or pulling out the load. When the epoxy resin is completely cured, the joint and the pipe body together with the epoxy resin are cut along the surface along the central axis of the pipe body, and the cut surface is polished for easy observation. Using a digital microscope capable of image measurement, observe the cut section and measure the angle. The angle α between the central axis of the tubular body and the center line of the gripper claw is measured, and "the angle α1 (degree) of the claw with respect to the central axis of the tubular body when the tubular body is inserted into the hollow joint. ". Joints are joined to both ends of the pipe body cut to a length of about 100 mm. Fix the joint joined to the pipe body to the tensile tester. The joint and the pipe body fixed to the tensile tester are held in a state where a tensile load of 50 N is applied, and epoxy resin is poured and cured so that the joint portion between at least one pipe body and the joint is filled with the resin. When the epoxy resin is completely cured, the tensile load of the tensile tester is released and the joint and the pipe body are removed from the tensile tester. The joint and the pipe body are cut along the surface along the central axis of the pipe body together with the cured epoxy resin, and the cut surface is polished for easy observation. Using a digital microscope capable of image measurement, observe the cut section and measure the angle. The angle α between the center axis of the tube and the center line of the gripper claw is measured, and the angle α2 (the angle of the claw with respect to the center axis of the tube when a pull-out load of 50 N is applied to the tube is α2 ( Degree) ”.
When the center line of the claw of the claw portion is composed of a curve, the line connecting the center of the tip of the claw portion and the center of the place serving as the fulcrum on the joint body side of the gripper is defined as the center line of the claw portion.

<Measurement of the amount of claws biting into the tube>
Using a digital microscope capable of image measurement, a sample prepared by cutting the joint and the tube along the surface along the tube center axis prepared in the above <Measurement of the angle of the gripper claw with respect to the tube center axis> Observe and measure the bite depth of the claw with respect to the wall thickness of the tube. The procedure is as follows. From the image, the line of the claw surface 122A of the gripper claw portion 122, the line of the outer surface 2a of the tube body and the line of the inner surface 2b of the tube body are extracted. On the image, the line of the outer surface 2a of the tube is extended so as to cross the claw of the gripper, and the extended line is referred to as the line 2A of the outer wall of the tube. If the inner surface of the tube is deformed due to the claws biting into the tube, the line connecting the parts where the inner surface of the tube is not deformed with a straight line is the line of the inner wall of the tube. When it is adopted as 2B (see FIG. 6) and the inner surface of the pipe body is not deformed, the line of the inner surface 2b of the pipe body is used as it is as the line 2B of the inner wall of the pipe body. The vertical distance from the line 2A on the outer wall of the tube to the line 2B on the inner wall of the tube is defined as the thickness of the tube. It is preferable to measure the thickness of the tube at several points and use the average value. The biting depth of the claw portion is the distance from the line 2A of the outer wall of the tubular body to the deepest and deepest biting position of the claw portion 122 in the thickness direction of the tubular body. The amount of the claws biting into the tube is calculated from these measured values as follows. Amount of claws biting into the tube (%) = (depth of claws biting / thickness of tube) x 100
<Measurement of pull-out strength>
To measure the pull-out strength of a joint, use a hard nylon tube as the pipe body, join the joint to the pipe body, install it in a tensile tester, and pull out in accordance with the pull-out strength test conditions of JIS standard JIS B 8381-1. Measure the strength. Specifically, a nylon tube cut to a length of 100 mm is joined to both ends of a nylon tube, and the joint portion is fixed to a tensile tester. The tensile tester is operated, the pipe body is pulled at a pull-out speed of 200 mm / min, and the load when the pipe body is pulled out from the joint is measured and used as the pull-out strength of the joint. The measurement is performed in an atmosphere of 23 ° C. ± 2 ° C.
<Airtightness test>
In the airtightness test of the joint, a hard nylon tube is used as the pipe body, and the inside of the pipe body is pressurized to check for fluid leakage. Specifically, a nylon tube cut to a length of 100 mm is joined to a joint, the inside of the tube is pressurized to 1 MPa and 5 MPa with a fluid, and held for 5 minutes to check for fluid leakage. Nitrogen, water and oil (silicon oil) are used as fluids. It is OK if no leakage is confirmed in any of the fluids.
<Pressure test>
For the pressure resistance test of the joint, a hard nylon tube or polyether ether ketone (PEEK) tube is used as the pipe body, and with the joint joined to the pipe body, the pressure inside the pipe is increased to damage the joint or the pipe body. If this occurs, or if the pipe comes out of the joint, check the pressure value. Specifically, when a nylon tube cut to a length of 100 mm is joined to a joint at both ends and air is injected from one of the joints to pressurize the nylon tube, the joint or the pipe body is damaged, or the pipe body is removed from the joint. Check the pressure when it comes off, and use it as the pressure resistance test value. If the withstand voltage exceeds 15 MPa, the hard nylon tube may be damaged, so the measurement is performed using the PEEK tube as the tube body.
<Repeated attachment / detachment test>
Repeat the airtightness test on the joint after the pressure resistance test, and check the number of repetitions until fluid leakage occurs. In the pressure resistance test, if the pipe body cannot be attached or detached due to damage to the gripping tool or other joint parts, it shall be NG.
<Measurement of crushing resistance of grippers>
Place it on a flat surface so that the tip of the claw of the gripper is on the lower side, and press a block large enough to cover the annular part of the gripper against the gripper and compress it at a speed of 5 mm / min to reduce the amount of pushing. The load when it reaches 0.5 mm is defined as the crushing resistance of the gripper.
<Measurement of tube hardness>
The hardness of the pipe body to be joined to the insertion joint of the present invention is measured according to JIS K7215. The tube of the measurement sample is divided in half along the longitudinal direction, and the indenter is vertical in a stable state by covering it on a metal cylinder or a thick metal pipe with the same outer diameter as the inner diameter of the tube. Press it against the surface of the tube so that it becomes, and measure within 1 second. Measure at 10 points and use the average value as the hardness.

Examples 1 to 4, Comparative Example 1
A plug-in type joint with a size for an outer diameter of 4 mm was created and evaluated. When the tube is inserted into the hollow part of the plug-in joint, the angle α1 (degree) of the claw of the gripper with respect to the center axis of the tube, and the claw of the grip when a pull-out load of 50 N is applied to the tube. The gripping tool and the mutual arrangement were designed so that the angle α2 (degrees) of the portion with respect to the central axis of the tube body was the angle shown in Table 1. Table 1 shows the results of various evaluations of the pull-out strength, airtightness test, pressure resistance test, and repeated attachment / detachment test of the joints of each Example and Comparative Example. For the evaluation tube, a nylon tube having a hardness of HDD80 measured in accordance with JIS K7215 and an outer diameter of 4 mm was used.

In Examples 1 to 4, the change in the angle of the claw portion of the gripping tool with respect to the central axis of the tube body is small when the tube body is inserted into the joint and when a pull-out load of 50 N is applied to the tube body, and the gripping tool The relationship between the angle α1 (degree) of the claw with respect to the central axis of the tube and the angle α2 (degree) of the claw with respect to the central axis of the tube when a pull-out load of 50 N is applied to the tube is -2 ≤ α2-α1 < The amount of satisfying 35 and the amount of the claws biting into the tube was in the range of 3% or more and less than 35% of the thickness of the tube, and the durability in the pressure resistance test was good. Further, in the repeated attachment / detachment test, sufficient performance was maintained even after repeated use after the test. FIG. 6 shows the results of the pressure resistance test of each Example and Comparative Example when the angle α1 (degree) of the claw portion of the gripper with respect to the central axis of the tube body and a pull-out load of 50 N were applied to the tube body. Relationship of angle α2 (degrees) with respect to the central axis of the tube body The figure shows the value of α2-α1 on the horizontal axis and the pressure resistance test value on the vertical axis.
In particular, in Examples 1 and 2, the angle α1 (degree) of the claw portion of the gripper with respect to the central axis of the tube body and the angle α2 of the claw portion with respect to the central axis of the tube body when a pull-out load of 50 N is applied to the tube body. The relationship of (degrees) was in the range satisfying -2≤α2-α1≤10, and the durability in the pressure resistance test and the repeated attachment / detachment test was particularly excellent.

Even when used under conditions where the use of conventional plug-in type joints has been restricted, or when the pipe body is repeatedly attached and detached, it is difficult for the pipe body to come off or fluid leakage, and as a pneumatic or hydraulic plug-in type joint. Widely available.

1 fitting, 110 fitting body, 120 gripping tool, 130 seal ring, 140 presser ring, 150 release sleeve, 2 pipe body

Claims

A pipe provided with a joint body into which a pipe body can be inserted into a hollow portion, a gripping tool inside the joint body that grips the outer periphery of the pipe body, and a seal ring that fills a gap between the hollow portion and the pipe body. It ’s a fitting,
The gripper includes an annular portion and a plurality of claw portions extending inward from the annular portion and obliquely in the insertion direction of the tubular body.
When the angle of the claw portion with respect to the central axis of the tubular body when the tubular body is inserted into the hollow portion is α1 (degrees), α1 is greater than 40 and 70 or less, and a withdrawal load of 50 N is applied to the tubular body. Assuming that the angle of the claw portion with respect to the central axis of the tube body is α2 (degrees), the claw portion satisfies the following formula (1) and the tube body is inserted into the hollow portion. A pipe joint to which a pipe body is connected, wherein the amount of the pipe biting into the pipe body is 3% or more and less than 35% of the thickness of the pipe body.
-2 ≤ α2-α1 <35 (1)
In claim 1, the angle α1 (degree) between the claw and the central axis of the tube and the angle α2 (degree) between the claw and the central axis of the tube satisfy the following formula (2), and the hollow portion. A pipe joint to which a pipe body is connected, wherein the amount of the claw portion biting into the pipe body in a state where the pipe body is inserted is 3% or more and less than 28% of the thickness of the pipe body.
-2 ≤ α 2-α 1 ≤ 25 (2)
In claim 1, the angle α1 (degree) between the claw and the central axis of the tube and the angle α2 (degree) between the claw and the central axis of the tube satisfy the following formula (3), and the hollow portion. A pipe joint to which a pipe body is connected, wherein the amount of the claw portion biting into the pipe body in a state where the pipe body is inserted is 3% or more and less than 15% of the thickness of the pipe body.
-2 ≤ α 2-α 1 ≤ 10 (3)
The pipe joint to which the pipe body connected to the plug-in type joint is connected according to claim 1 to 3, wherein the pipe body connected to the plug-in type joint has a hardness of HDD60 or more measured in accordance with JIS K7215.