JP6788324B2 - Pipe fitting - Google Patents

Description

The present invention relates to pipe fittings used for pipes for water supply, hot water supply, etc., for example.

As a conventional pipe joint, a pipe body (intermediate ring) and a pipe, which are configured so that a tubular member is inserted on the inner peripheral side and a pair of convex portions separated from each other in the axial direction are formed on the outer peripheral surface. A cap (sleeve), which is inserted from one end in the axial direction of the main body around the outer peripheral surface of the pipe main body and has a pair of concave portions formed on the inner peripheral surface to engage with a pair of convex portions of the pipe main body. Those provided are known (for example, Patent Document 1). When the tubular member is inserted, the tube main body and the cap accommodate the claws that bite into the outer peripheral surface of the tubular member and prevent the tubular member from moving in the axial direction so as to sandwich the claws from both sides in the axial direction. The engagement between the convex part of the pipe body and the concave part of the cap prevents the cap from coming off the pipe body even if the tubular member inserted into the pipe joint is pulled or the inside of the pipe becomes high pressure. There is.

Japanese Patent Application Laid-Open No. 2005-188705

As described above, the holding force between the pipe body and the cap, which acts to prevent the cap from coming off the pipe body, is obtained by forming a higher radial outward protrusion height of the convex portion of the pipe body. , Can be enhanced. However, if the protruding height of the convex portion of the pipe body is increased, the load applied to the engaging portion between the pipe body and the cap when the cap is inserted around the pipe body is increased, so that the pipe is piped. The main body and cap may be damaged (for example, the pipe main body and / or the engaging portion of the cap may be chipped, or the pipe main body and / or the cap may be cracked). On the other hand, if the convex portion is simply enlarged in order to increase the protruding height of the convex portion of the pipe body portion, the axial length of the pipe main body portion and the cap will be increased accordingly, resulting in compactness in the axial direction. There was a problem that the sex was impaired.

The present invention is for solving the above-mentioned problems, and is to increase the holding force between the pipe body and the cap while suppressing damage and deterioration of compactness when the cap is inserted into the pipe body. The purpose is to provide pipe fittings that can be used.

The pipe joint of the present invention is inserted around the outer peripheral surface of the pipe body portion from the pipe body portion configured so that a tubular member is inserted on the inner peripheral side and the axial first end of the pipe body portion. A second engaging convex portion and a second engaging convex portion arranged on the outer peripheral surface of the tube main body portion on the second side in the axial direction with respect to the first engaging convex portion. An engaging convex portion is formed, and the cap is inserted into the inner peripheral surface of the cap from the end on the first side in the axial direction of the pipe main body around the outer peripheral surface of the pipe main body. At that time, a first engaging concave portion and a second engaging concave portion that engage with the first engaging convex portion and the second engaging convex portion are formed, and the first engaging convex portion and the first engaging convex portion are formed. The outer peripheral surface of the two engaging convex portions has a diameter-expanded surface portion whose diameter is gradually increased from the end on the first side in the axial direction toward the second side in the axial direction, respectively, in the axial direction. In the cross section along the line, the angle formed by the sharp angle side with respect to the axial direction of the line segment connecting both ends in the axial direction of the enlarged surface portion of the first engaging convex portion is the axial direction of the enlarged surface portion of the second engaging convex portion. It is characterized in that it is smaller than the angle formed by the sharp angle side with respect to the axial direction of the line segment connecting both ends.
According to the pipe joint of the present invention, it is possible to increase the holding force between the pipe body and the cap while suppressing damage and a decrease in compactness when the cap is inserted into the pipe body.

In the pipe joint of the present invention, it is preferable that the maximum outer diameter of the first engaging convex portion is smaller than the maximum outer diameter of the second engaging convex portion. According to this, the breakage can be suppressed more effectively.

In the pipe joint of the present invention, the axial length of the portion on the inner peripheral surface of the cap on the second side in the axial direction from the second engaging recess is the first on the outer peripheral surface of the pipe body. It is preferable that the length of the portion between the engaging convex portion and the second engaging convex portion is longer than the axial length. According to this, the breakage can be suppressed more effectively.

According to the present invention, it is possible to provide a pipe joint capable of increasing the holding force between the pipe body and the cap while suppressing breakage and deterioration of compactness when the cap is inserted into the pipe body. it can.

It is sectional drawing along the axis direction which shows one Embodiment of the pipe joint of this invention in the state of use. It is sectional drawing of the main part of the pipe joint shown in FIG. It is sectional drawing of the main part which shows the modification of the pipe joint of this invention.

Hereinafter, embodiments of the pipe joint according to the present invention will be illustrated and described with reference to the drawings.

1 and 2 show an embodiment of the pipe fitting of the present invention in its used state. FIG. 1 is a cross-sectional view showing the pipe joint 1 of the present embodiment along the axial direction of the pipe joint 1 (the left-right direction of FIG. 1), and FIG. 2 is a portion surrounded by a broken square in FIG. It is an enlarged sectional view. In the example of the usage state of FIG. 1, a total of four pipe joints including three pipe joints 1 of the present embodiment and one other pipe joint 100 are connected in the axial direction (left-right direction of FIG. 1). Connected to each other. Of the four pipe joints, the two pipe joints 1a in the middle are related to the present embodiment, are configured in a substantially T shape, and are on the first side in the axial direction (the right side in FIG. 1, the same applies hereinafter). The pipe connection port 81 is provided at the center, and the end portion on the second side in the axial direction (the left side in FIG. 1; the same applies hereinafter) is formed in a tubular shape, and further branches from the pipe between both ends in the axial direction in the axial direction. It has a pipe connection port 83 that faces in a direction perpendicular to the above. The pipe joint 1b on the secondmost side in the axial direction also relates to the present embodiment and is configured in a substantially T shape, and pipe connection ports 81 and 82 are provided on the first side and the second side in the axial direction, respectively. It also has a pipe connection port 83 that branches off from the pipe between both ends in the axial direction and faces the direction perpendicular to the axial direction. The pipe joint 100 on the first side in the axial direction is formed in a substantially L shape, the end on the second side in the axial direction is formed in a tubular shape, and the pipe is oriented in the direction perpendicular to the axial direction. It has a connection port 83.
In this example, the tubular portion (tubular member 30) of the adjacent pipe joint is inserted into the pipe connection port 81 on the first side in the axial direction of the pipe joints 1a and 1b according to the present embodiment on the inner peripheral side thereof. It is connected to this. The tubular portion (tubular member 30) on the second side in the axial direction of the two intermediate pipe joints 1a and the pipe joint 100 on the first side in the axial direction is located on the inner peripheral side of the pipe connection port 81 of the adjacent pipe joint. It is plugged in and connected. The pipe connection port 83 facing the direction perpendicular to the axial direction in each of the pipe joints 1 and 100 and the pipe connection port 82 on the second side in the axial direction in the pipe joint 1b on the secondmost side in the axial direction are respectively. For example, it is connected to a tubular member such as a water supply / hot water supply pipe (not shown) made of polybutene.
However, the pipe joint 1 of the present invention may be formed in any shape such as a substantially L-shape, a substantially I-shape, and a substantially cross shape.

The pipe joint 1 of the present embodiment is formed from a pipe body 10 configured such that a tubular member 30 is inserted into the inner peripheral side and an end of the pipe body 10 on the first side in the axial direction (right side in FIG. 1). It includes a tubular cap 20 that is inserted around the outer peripheral surface of the pipe body 10, and these form a part of the pipe connection port 81 on the first side in the axial direction in this example. ..
Here, "insertion" refers to pushing in the axial direction without rotating, and is a concept including press fitting.
In this example, the cap 20 is elastically deformable and is made of a material softer than the tube body 10. The tube body 10 is formed of, for example, a metal such as bronze or brass, a resin such as polyphenylene sulfide (PPS), polyether sulfide (PES), polycarbonate (PC), or nylon (PA). The cap 20 is formed of, for example, a resin such as polyoxymethylene (POM), polyether sulfone (PES), polyphenylene sulfide (PPS) or nylon (PA). Glass may be optionally added to the resin used for the tube body 10 and the cap 20.
By making the cap 20 elastically deformable, when the cap 20 is inserted around the outer peripheral surface of the pipe body 10, the diameter of the cap 20 is easily expanded, so that the cap 20 can be easily inserted.
However, in the present embodiment, at least one of the cap 20 and the pipe body 10 may be elastically deformable, that is, the hardness of the cap 20 and the pipe body 10 may be the same, or the pipe. The main body 10 may be made softer than the cap 20.

As shown in FIG. 2, on the outer peripheral surface of the pipe main body 10, in the example of the figure, the first engagement is arranged adjacent to the end of the pipe main body 10 on the first side in the axial direction (right side of FIG. 2). The combined convex portion 101 and the second engaging convex portion 102 arranged on the second side (left side in FIG. 2) in the axial direction from the first engaging convex portion 101 are integrally formed with the pipe main body portion 10. ing. Further, on the inner peripheral surface of the cap 20, when the cap 20 is inserted around the outer peripheral surface of the pipe body 10 from the end on the first side in the axial direction of the pipe body 10, the first engaging convex portion is provided. The first engaging recess 201 and the second engaging recess 202 that engage with the 101 and the second engaging convex portion 102 are formed on the second side portion in the axial direction of the cap 20 in the example of FIG. .. That is, the second engaging recess 202 is arranged on the second side in the axial direction with respect to the first engaging recess 201.

As shown in FIG. 2, the outer peripheral surfaces of the first engaging convex portion 101 and the second engaging convex portion 102 are gradually increased in diameter from the end on the first side in the axial direction toward the second side in the axial direction. In addition, it has enlarged diameter surface portions 101a and 102a, respectively.

As shown in FIG. 2, in this example, in the cross section along the axial direction, the angle α formed on the acute angle side with respect to the axial direction of the line segment connecting both ends in the axial direction of the enlarged diameter surface portion 101a of the first engaging convex portion 101 is It is smaller than the angle β formed by the acute angle side with respect to the axial direction of the line segment connecting both ends in the axial direction of the enlarged diameter surface portion 102a of the second engaging convex portion 102 (that is, 0 <α <β <90 °). By making the angle α formed by the enlarged diameter surface portion 101a of the first engaging convex portion 101 with respect to the axial direction relatively small, the inner peripheral surface of the cap 20 is expanded by expanding the first engaging convex portion 101 when the cap 20 is inserted. Since the diameter surface portion 101a can moderate the change in the diameter expansion amount with respect to the pushing amount of the cap, it is possible to reduce the load applied to the engaging portion between the inner peripheral surface of the cap 20 and the outer peripheral surface of the pipe body portion 10. Damage to the cap 20 and the pipe body 10 can be suppressed. Further, by relatively increasing the angle β formed by the enlarged diameter surface portion 102a of the second diameter convex portion 102 with respect to the axial direction, for example, the first and second engaging convex portions 101 and 102 can be moved outward in the radial direction. Without changing the protruding height, the angle α formed by the enlarged surface portion 101a of the first diameter convex portion 101 with respect to the axial direction is the angle β formed by the angle β formed by the enlarged surface portion 102a of the second diameter convex portion 102 with respect to the axial direction. Compared with the same case, the lengths of the pipe body 10 and the cap 20 in the axial direction can be shortened, so that the compactness in the axial direction can be improved. Further, as a result, if the protruding heights of the first engaging convex portion 101 and the second engaging convex portion 102 are increased as compared with the conventional case, the holding force between the cap 20 and the pipe main body 10 is improved. However, it is possible to suppress a decrease in compactness in the axial direction.
As described above, according to the pipe joint 1 of the present embodiment, the holding force between the pipe body 10 and the cap 20 can be suppressed while suppressing damage and deterioration of compactness when the cap 20 is inserted into the pipe body 10. It is possible to increase.

In the example of FIG. 2, in the cross section along the axial direction, the enlarged diameter surface portions 101a and 102a extend straight with the inclination angles α and β on the acute angle side with respect to the axial direction, respectively, that is, formed in a tapered shape. Has been done. However, the present invention is not limited to this, and in the cross section along the axial direction, the enlarged diameter surface portions 101a and 102a are convex inward or outward in the radial direction of the pipe joint 1 with respect to the line segment connecting both ends in the axial direction. In addition, it may be curved or bent at one or more points.
In the cross section along the axial direction, the enlarged diameter surface portions 101a and 102a are curved or at one or more points so as to be convex inward in the radial direction of the pipe joint 1 with respect to the line segment connecting both ends in the axial direction. When the cap 20 is bent, when the cap 20 is inserted into the pipe body 10, the change in the diameter expansion amount with respect to the pushing amount of the cap 20 at the initial stage of the diameter expansion of the cap 20 can be moderated. It is possible to reduce the load on the pipe body 10.
Further, in the cross section along the axial direction, the enlarged diameter surface portions 101a and 102a are curved or at one place so as to be convex outward in the radial direction of the pipe joint 1 with respect to the line segment connecting both ends in the axial direction. When bent as described above, the load on the cap 20 and the pipe body 10 is likely to be the highest, and the change in the diameter expansion amount with respect to the pushing amount of the cap 20 can be moderated immediately before the completion of the diameter expansion of the cap 20. , The load on the cap 20 and the pipe body 10 can be greatly reduced.

In the example of FIG. 2, the axial length L2 of the portion on the inner peripheral surface of the cap 20 on the second side (left side in FIG. 2) in the axial direction with respect to the second engaging recess 202 is the outer peripheral surface of the pipe body 10. Is longer than the axial length L1 of the portion between the first engaging convex portion 101 and the second engaging convex portion 102 (that is, L2> L1). Here, "the axial length L1 of the portion between the first engaging convex portion 101 and the second engaging convex portion 102 on the outer peripheral surface of the pipe main body 10" is the outer peripheral surface of the pipe main body 10. Refers to the axial length of the portion from the second end in the axial direction of the first engaging convex portion 101 to the first end in the axial direction of the second engaging convex portion 102. Further, "the axial length L2 of the portion on the inner peripheral surface of the cap 20 on the second side in the axial direction with respect to the second engaging recess 202" is the second engaging recess 202 on the inner peripheral surface of the cap 20. Refers to the axial length of the portion from the second end in the axial direction of the cap 20 to the second end in the axial direction of the inner peripheral surface of the cap 20. According to this, when the cap 20 is inserted from the end of the pipe body 10 on the first side in the axial direction, the portion of the cap 20 on the second side in the axial direction with respect to the second engaging recess 202 is the pipe body. Since it hits the enlarged diameter surface portion 102a before being fitted into the portion between the first engaging convex portion 101 and the second engaging convex portion 102 in No. 10, the amount of diameter reduction of the cap 20 is suppressed and the cap 20 After the portion on the second side in the axial direction with respect to the second engaging recess 202 hits the diameter-expanded surface portion 102a, the amount of diameter expansion of the cap 20 when the diameter is expanded again is suppressed. As a result, the load applied to the cap 20 and the pipe body 10 can be further reduced, and damage to the cap 20 and / or the pipe body 10 can be suppressed more effectively. Further, by making the axial length L2 of the portion on the inner peripheral surface of the cap 20 on the second side in the axial direction with respect to the second engaging recess 202 relatively long, the second engaging recess 202 of the cap 20 Since the volume of the portion on the second side in the axial direction can be sufficiently secured and the deformation can be made difficult, the holding force between the pipe body portion 10 and the cap 20 can be increased.

In the example of FIG. 2, the axial length L2 of the portion on the inner peripheral surface of the cap 20 on the second side (left side in FIG. 2) in the axial direction with respect to the second engaging recess 202 is the first of the pipe body 10. It is longer than the axial distance L3 between the radial outermost (protruding tip) 101b of the engaging convex portion 101 and the radial outermost (protruding tip) 102b of the second engaging convex 102. (That is, L2> L3). Here, "the axial distance L3 between the radial outermost 101b of the first engaging convex portion 101 of the pipe main body 10 and the radial outermost 102b of the second engaging convex portion 102" is the pipe main body. Axial line from the axial second side end of the radial outermost 101b of the first engaging convex portion 101 of the portion 10 to the axial first side end of the radial outermost 102b of the second engaging convex portion 102. Refers to the directional distance. According to this, when the cap 20 is inserted from the end of the pipe body 10 on the first side in the axial direction, the portion of the cap 20 on the second side in the axial direction with respect to the second engaging recess 202 is in the first engagement. Since the diameter of the second diameter convex portion 102 can be overcome without being reduced in diameter between the time when the convex portion 101 is hit and the time when the convex portion 102 is hit, the damage can be suppressed more effectively. Further, by making the axial length L2 of the portion on the inner peripheral surface of the cap 20 on the second side in the axial direction with respect to the second engaging recess 202 relatively long, the second engaging recess 202 of the cap 20 Since the volume of the portion on the second side in the axial direction can be sufficiently secured and the deformation can be made difficult, the holding force between the pipe body portion 10 and the cap 20 can be increased.

In the example of FIG. 2, the outermost 101b in the radial direction of the first engaging convex portion 101 and the outermost 102b in the radial direction of the second engaging convex portion 102 each extend a certain length along the axial direction. It is postponed. As a result, as compared with the case where the radial outermost 101b of the first engaging convex portion 101 and the radial outermost 102b of the second engaging convex portion 102 are sharper, for example, the first engaging convex portion 101 and Since the rigidity of the second diameter convex portion 102 can be increased, damage during insertion can be suppressed.

Further, in the example of FIG. 2, the maximum outer diameter of the first engaging convex portion 101 is the same as the maximum outer diameter of the second engaging convex portion 102.

Further, in the example of FIG. 2, on the outer surfaces of the first engaging convex portion 101 and the second radial convex convex portion 102, the portions 101c and 102c on the second side in the axial direction with respect to the outermost parts 101b and 102b in the radial direction are substantially formed. It extends along the radial direction. As a result, on the outer surface of the first engaging convex portion 101 and the second radial convex portion 102, the portions 101c and 102c on the second side in the axial direction with respect to the outermost parts 101b and 102b in the radial direction are provided as the outermost parts in the radial direction. The holding force between the pipe body 10 and the cap 20 can be improved as compared with the case where the 101b and 102b are inclined from the end on the second side in the axial direction toward the twelfth side in the axial direction.

In this example, the first engaging convex portion 101 and the second engaging convex portion 102 are formed in an annular shape so as to extend over the entire circumference of the pipe joint 1 in the circumferential direction. However, the present invention is not limited to this, and the first engaging convex portion 101 and the second engaging convex portion 102 may each be composed of a plurality of convex portions arranged at intervals along the circumferential direction. In that case, the first engaging recess 201 and the second engaging recess 202 may be formed in an annular shape, or may be composed of a plurality of recesses arranged at intervals along the circumferential direction.

In the example of FIG. 2, a step 103 configured to abut on the outer peripheral surface of the pipe body 10 so as to abut the end surface of the cap 20 on the second side in the axial direction when the cap 20 is inserted into the pipe body 10. It is formed.

In the example shown in FIG. 2, the pipe connection port 81 on the first side in the axial direction of the pipe joint 1 is further aligned with the O-ring 70 abutting on the inner peripheral surface of the pipe body 10 and the O-ring 70. The contact ring 40 adjacent to the first side in the direction and in contact with the inner peripheral surface of the pipe body 10 and the end surface on the first side in the axial direction, and adjacent to the first side in the axial direction with respect to the contact ring 40. , A claw portion 50 configured to bend in a substantially V-shape convex in the first side in the axial direction, and its inner peripheral end portion bites into the outer peripheral surface of the tubular member 30 to hold the tubular member 30. It is provided with a release ring 60 which is arranged on the first side in the axial direction with respect to the portion 50 and is configured so that the claw portion 50 can be released from biting into the tubular member 30. The abutting ring 40, the claw portion 50, and the release ring 60 are arranged on the inner peripheral side of the cap 20. The tube body 10 and the cap 20 regulate the axial displacement of the O-ring 70, the abutting ring 40, the claw 50, and the release ring 60. Then, a tubular member 30 is provided on the inner peripheral side of each of the second side portion of the pipe body 10 in the axial direction with respect to the O-ring 70, the O-ring 70, the contact ring 40, the claw portion 50, and the release ring 60. It is plugged in.
However, the pipe body 10 and the cap 20 described in this embodiment can be applied to a pipe connection port (and thus a pipe joint) having any other configuration.
Further, in this example, the tubular portion (tubular member 30) of another pipe joint is configured to be inserted into the inner peripheral side of the pipe body portion 10 described in the present embodiment, but the pipe of the present embodiment is configured. The joint 1 may be configured such that another arbitrary tubular member (for example, a water supply / hot water supply pipe or the like) is inserted into the inner peripheral side of the pipe body 10.

The pipe joint 1 of the present embodiment is not limited to the one described above, and various modifications can be made.
FIG. 3 is a cross-sectional view in the axial direction showing a modification of the pipe joint 1 of the present embodiment, and is a diagram corresponding to FIG. In the example of FIG. 3, the maximum outer diameter of the first engaging convex portion 101 is made smaller than the maximum outer diameter of the second engaging convex portion 102, and the first engaging concave portion 201 and the second engaging concave portion 201 and the second engaging portion 102 are engaged. It differs from the example of FIG. 2 only in that the concave portion 202 is shaped so as to match the first engaging convex portion 101 and the second engaging convex portion 102, respectively. According to this, when the cap 20 is inserted into the pipe body 10, the inner peripheral surface of the cap 20 gradually expands in diameter while hitting the first engaging convex portion 101 and the second engaging convex portion 102. , Damage can be suppressed more effectively.

Further, three or more engaging convex portions arranged in the axial direction may be formed on the outer peripheral surface of the pipe body portion 10. In that case, of the three or more engaging convex portions, the two engaging convex portions closest to the end on the first side in the axial direction of the pipe body portion 10 are the first engaging convex portions 101 and the second engaging convex portion described above. It is preferable to have the structure of the engaging convex portion 102.

(Example)
Comparative Examples 1 and 2 and Example 1 of the pipe joint were prototyped, and a test of inserting the cap into the pipe body was carried out to evaluate whether or not the cap and the pipe body were damaged. In each Comparative Example and Example, only the dimensions of the first engaging convex portion and the second engaging convex portion (and thus the dimensions of the first engaging concave portion and the second diameter concave portion) were different from each other. The specifications of each comparative example and embodiment are as shown in Table 1.
In Table 1, the "protruding height" refers to the radial lengths of the first engaging convex portion and the second engaging convex portion. In each of the comparative examples and the examples, the protruding height (diameter length) of the first engaging convex portion and the second engaging convex portion was the same. In Table 1, "compactness" refers to compactness in the axial direction of the pipe joint, and the protruding heights of the first engaging convex portion and the second engaging convex portion in each of the comparative examples and examples are high. It was evaluated that the smaller the angle α and β, the worse the compactness. In Table 1, the "holding force" refers to the holding force between the pipe body and the cap, and the higher the protruding height of the first engaging convex portion and the second engaging convex portion, the higher the holding force. Evaluated as something to do.

As can be seen from the results in Table 1, according to the pipe joint of Example 1, the pipe body and the cap are separated from each other while preventing damage when the cap is inserted into the pipe body and obtaining good compactness. It is possible to increase the holding power of.

The fittings according to the invention can be used for piping for any fluid such as cold water, hot water, oil and the like.

1, 1a, 1b, 100: Pipe joint, 10: Pipe body, 20: Cap, 30: Tubular member, 50: Claw, 60: Release ring, 70: O ring, 81-83: Pipe connection port, 101 : 1st engaging convex portion, 101a: Enlarged surface portion of the 1st engaging convex portion, 101b: Radial outermost part of the 1st engaging convex portion, 101c: Radial direction on the outer surface of the 1st engaging convex portion Second side in the axial direction from the outermost part, 102: Second engaging convex part, 102a: Expanded surface part of the second engaging convex part, 102b: Outermost part in the radial direction of the second engaging convex part, 102c: On the outer surface of the second engaging convex portion, the portion on the second side in the axial direction with respect to the outermost radial portion, 201: the first engaging concave portion, 202: the second engaging concave portion.

Claims (3)

A tube body configured to insert a tubular member on the inner circumference side,
A tubular cap inserted around the outer peripheral surface of the pipe body from the first end in the axial direction of the pipe body, and
With
A first engaging convex portion and a second engaging convex portion arranged on the second side in the axial direction with respect to the first engaging convex portion are formed on the outer peripheral surface of the pipe main body portion.
When the cap is inserted around the outer peripheral surface of the pipe body portion from the end on the first side in the axial direction of the pipe body portion on the inner peripheral surface of the cap, the first engaging convex portion is provided. And a first engaging recess and a second engaging recess that engage with the second engaging protrusion are formed.
The outer peripheral surfaces of the first engaging convex portion and the second engaging convex portion have diameter-expanded surface portions that are gradually increased in diameter from the respective ends on the first side in the axial direction toward the second side in the axial direction. Have each
In the cross section along the axial direction, is engaged with the first engagement recess of said cap, said first engaging portion of the tube body portion, the axis of the line segment connecting the axial ends of said radially enlarged surface portion line segment acute side angle of relative to the direction, which is engaged with the second engagement recess of the cap, the second engaging portion of the tube body portion, connecting the axial ends of said radially enlarged surface portion A pipe joint characterized in that it is smaller than the angle formed by the sharp angle side with respect to the axial direction of. Maximum outer diameter of the first engaging portion, the rather smaller than the maximum outer diameter of the second engaging portion, and said first engaging recess and the second engaging recess, said respective first The pipe joint according to claim 1, which is shaped to match the engaging convex portion and the second engaging convex portion . The axial length of the portion on the inner peripheral surface of the cap that is axially second to the second engaging recess is the first engaging convex portion and the first engaging convex portion on the outer peripheral surface of the pipe body. 2. The pipe joint according to claim 1 or 2, which is longer than the axial length of the portion between the engaging convex portion.