JP2002317890A - Tube joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube joint securely capable of preventing coming-out of a tube even when water infiltrating into a holder inner part of a cylindrical main body part from the external is frozen. SOLUTION: As an end part 42 of the tube 41 is inserted into the main body part 10, a tip part of it presses a coil spring 38 inserted into a third hole 14 to be engaged to a circular surface adjacent to a fourth hole 15 to be extended in a diametric direction to compress it. In addition, the tube is slightly pulled back, and a claw part 33b of a tightening member 31 bites an outer circumferential surface at an end part of the tube, so that the tube is tightly connected to a holder 25 in the main body part. A compressed state of the coil spring pressed into the third hole is loosened, and energization force by the coil spring is applied to the tube tip side. When this tube joint receives vibration in a non-pressurized state, move of the tube is prohibited by energization force of the coil spring, thereby the tightened state by the tightening member is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-assembled tube joint which can be connected by pulling back an inserted resin tube.

[0002]

2. Description of the Related Art Conventionally, as shown in, for example, Japanese Patent Application Laid-Open No. 2001-4084, this type of tube joint gradually decreases in diameter from one end to the other end. A first hole 11a extending in the axial direction having an inner diameter,
A cylindrical main body 10 having a shaft hole provided with a second hole 11b and a third hole 11c is provided. The third hole 11c is
The end portion 91 of the tube 90 is formed so as to be able to be inserted in a closely contacting state. This tube joint has an insertion hole through which the end portion 91 of the tube 90 can be inserted, and the first hole 11
an annular rib 20 integrally provided at an inner portion of the inner peripheral portion a so as to protrude radially inward from the inner peripheral surface thereof; And a regulating concave tapered inner peripheral surface 31 having a diameter gradually increasing toward the other end adjacent to the guide inner peripheral surface 31a on the other end side.
b, the annular concave portion 7 is formed between the regulating concave taper inner peripheral surface 31b and the rib 20, and the cylindrical holder 30 having the other end of the outer peripheral surface fixed in the first hole 11a is provided. I have. Second
The annular elastic seal member 4 is mounted in the hole 11b. The tube joint has a cylindrical base 51 having an outer diameter slightly smaller than the inner diameter of the guide inner peripheral surface 31a having an outer peripheral surface slidable on the guide inner peripheral surface 31a of the holder 30 at one end of the shaft hole, A plurality of resiliently deformable arm portions 53 formed by providing cutouts extending from the base portion 51 toward the other end in the axial direction and spaced apart in the circumferential direction;
3 has a cylindrical fastening member 50 having a fastening portion 52 provided integrally with the free end. The inner peripheral surface of the base 51 is formed so that the distal end of the tube end 91 can be inserted.

[0003] The fastening portion 52 has a head 52a projecting radially outward and abutting on the inner peripheral surface 31b of the regulating concave taper, and an outer diameter of a tube 90 inserted projecting inward from the head 52a in the centripetal direction. And a claw portion 52b having a small-diameter tip inner diameter. Each of the arm portions 53 extends in the axial direction toward one end side adjacent to the fastening portion 52, and the guide inner peripheral surface 3.
An adjacent extension 53a having an outer diameter equal to or larger than the inner diameter of 1a, and a thin portion 53b extending between the adjacent extension 53a and the base 51 and having an outer peripheral surface smaller in diameter than the outer diameter of the base 51 are provided.

In this tube joint, the fastening portion 52 and the adjacent extension 53a of the fastening member 50 are accommodated in the annular concave portion 7 so as to be movable in the axial direction, while the end portion 91 of the tube 90 is provided.
When the front end portion is inserted through the fastening member 50, the rib 20, and the elastic seal member 4, and is inserted into the third hole 11c,
The elastic seal member 4 seals between the outer peripheral surface of the end portion 91 and the inner peripheral surface of the second hole 11b. When the tube 90 is slightly pulled back, the tightening member 50 is moved to one end together with the tube 90, and the head 52a comes into contact with the regulating concave tapered inner peripheral surface 31b and the head 52a is moved toward the regulating concave taper inner periphery. The arm 52 moves in the centripetal direction along the surface 31b so that the claw 52b bites into the outer peripheral surface of the tube end 91 and the arm 5
3 at least a portion of the adjacent extension 53a is the guide inner peripheral surface 31.
a.

[0005]

In the case where the above-mentioned tube joint is used for an auxiliary pipe to which an internal pressure is applied only when used, if the tube joint is subjected to vibration in a non-pressurized state, the difference between the pushing and the pulling of the tube 90 is obtained. Because there is a tube 9
0 is moved in the axial direction by the vibration, and the fastening portion 52 of the fastening member 50 is easily detached from the holder 30. When moisture enters the holder 30 from the outside in a state where the fastening portion 52 is disengaged from the holder 30 as described above, especially in winter or in a cold region, the entered moisture is frozen and the volume expands due to freezing, thereby causing the fastening member 50 to move. The diameter will be enlarged. Therefore, there is a problem that the tube 90 is insufficiently tightened by the tightening member 50 and the tube 90 is easily pulled out from the main body 10 when an internal pressure is applied to the tube joint. The present invention is intended to solve the above-described problem, and provides a tube joint that can reliably prevent the tube from coming off even when moisture that has entered the inside of the holder of the tubular main body from the outside freezes. The purpose is to do.

[0006]

In order to achieve the above object, a structural feature of the first aspect of the present invention is a pre-assembled tube joint which can be connected by pulling back an inserted resin tube. A shaft hole having a first hole, a second hole, a third hole, and a fourth hole extending in the axial direction having an inner diameter gradually decreasing from one end toward the other end. And a third hole having a cylindrical main body formed so that the end of the tube can be inserted in close contact with the end of the tube, and an insertion hole through which the end of the tube can be inserted. An annular rib integrally provided in an inner portion of the hole so as to protrude radially inward from an inner peripheral surface of the first hole; an inner peripheral surface and an outer peripheral surface; Is provided on one end side with a guide inner peripheral surface that extends straight parallel to the axis, and on the other end side, adjacent to the guide inner peripheral surface, toward the other end. A regulating concave taper inner peripheral surface having the next larger diameter is provided, an annular concave portion is formed between the regulating concave taper inner peripheral surface and the annular rib, and at least the other end of the outer peripheral surface is fixed in the first hole of the main body. Cylindrical holder, an annular elastic seal member inserted in the second hole, a coil spring inserted in the third hole, and sliding on one end side of the shaft hole on the guide inner peripheral surface of the holder. A cylindrical base having an outer diameter slightly smaller than the inner diameter of the guide inner peripheral surface having an outer peripheral surface made possible, and a notch spaced circumferentially extending from the base toward the other end in the axial direction are provided. A plurality of elastically deformable arms formed and a head arranged in an annular shape and provided integrally with the free ends of the respective arms, projecting radially outward and abutting on the inner peripheral surface of the regulating concave taper. Smaller than the outer diameter of the tube inserted protruding inward in the centripetal direction from the head A clamping portion having a claw portion having a tip inner diameter, and a tubular clamping member in which the clamping portion is axially movably accommodated in the annular concave portion; and When the coil spring is inserted inward from the fastening member, the rib, and the elastic seal member and inserted into the third hole of the main body, the coil spring moves radially outward adjacent to the fourth hole in the third hole. The outer circumferential surface of the end of the tube and the inner circumferential surface of the second hole are sealed by an elastic seal member, and when the tube is slightly pulled back, the tightening member is turned into a tube. Together with the end of the tube, the head of the tightening member comes into contact with the inner peripheral surface of the regulating concave taper, and the head moves in the centripetal direction along the inner peripheral surface of the regulating concave taper. Of the coil spring The tube is urged in the axial direction toward one end.

According to the first aspect of the present invention, when the end of the tube is inserted into the cylindrical main body, the distal end of the tube is inserted through the tightening member, the rib and the elastic seal member. It is inserted into the third hole of the main body. At this time, the distal end of the tube presses the coil spring inserted into the third hole against the radially extending annular surface adjacent to the fourth hole and compresses the coil spring. Then, the tube is pulled back slightly, so that the tightening member moves to one end together with the tube, and the head of the tightening member contacts the inner surface of the regulating concave taper of the holder, and the head of the tightening member becomes the inner surface of the restricting concave taper. Move in the centripetal direction along with the claw, and the claw bites into the outer peripheral surface of the end of the tube. Thereby, the tube is tightly connected to the main body by the fastening member.

On the other hand, by slightly pulling the tube back in this way, the compressed state of the coil spring, which has been pressed against the annular surface of the third hole by the tube tip, is loosened, and the tube spring is moved to the tip end of the tube end. The urging force of the coil spring acts. Therefore, even when the tube joint is in a non-pressurized state, the state where the claw bites into the tube is maintained, and even if vibration is applied to the tube joint and the tube moves inward in the axial direction, the coil spring is The movement is hindered by the biasing force. That is, the state in which the tube is tightened by the tightening member is maintained. As a result, when moisture that has entered the inside of the holder from outside freezes, the fastening member does not expand in diameter due to the volume expansion of the moisture due to freezing,
Therefore, the effect of tightening the tube of the tightening member does not decrease.

A structural feature of the second aspect of the invention is that, in the tube joint according to the first aspect, the coil spring has a length of substantially one turn. If the length of the coil spring is substantially one turn, the effect of urging the tube toward one end in the axial direction is obtained, and the length of the main body is not increased by making it unnecessary.

According to a third aspect of the present invention, in the tube joint according to the first or second aspect, one end is inserted and fixed in the fourth hole and the other end is the first. A metal tubular insertion tube member extending in the hole direction and having a tube inserted into the shaft hole inserted therein is provided on an outer periphery thereof, and a coil spring is inserted and fitted on the outer periphery of the insertion tube member. Is to be.

According to the third aspect of the present invention, there is provided a metal cylindrical insertion tube member having one end fixed to the fourth hole and the other end inserted into the tube. Since the coil spring is inserted into the outer periphery of the insertion tube member, the coil spring having a short axial length can be stably held in the third hole.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway front view showing a tube joint that can be connected by a pull-back operation of an inserted resin tube used for piping of an air brake of an automobile according to the embodiment. Also,
2, 4 and 5 are sectional views of a main part showing the progress of connecting the tubes of the tube joint.

The tube joint has a cylindrical main body 10 bent at a right angle at an intermediate position in the axial direction, and an insertion hole through which an end of the tube 41 can be inserted.
An annular rib 21 integrally provided at an inner end of the second hole so as to protrude radially inward from an inner peripheral surface of the first hole;
1, a cylindrical holder 25 fixed in the first hole 12 adjacent to the first hole 12, an annular elastic seal member 37 mounted in the second hole 13, and an insertion fit in the third hole 14. And a cylindrical fastening member 31 inserted into the insertion surface on the inner peripheral side of the holder 25. Main body 10
The holder 25 is generally made of metal such as brass or stainless steel, but may be made of a heat-resistant resin, for example, reinforced plastic such as glass-reinforced nylon reinforced with glass fiber. The fastening member 31 is made of a metal such as a copper alloy. As the material of the tube 41, nylon 11, nylon 12, or the like is preferably used.

The main body 10 includes a first connecting portion 10a on one end and a second connecting portion 10b on the other end bent at a right angle at an intermediate position in the axial direction. The end 42 of the resin tube 41 is connected, and a tube (not shown) is inserted into the outer peripheral surface of the second connection portion 10b. The first connection portion 10a has a shaft hole 11 extending in the axial direction having an inner diameter that gradually decreases in diameter from one end to the other end, and sequentially includes a first hole 12, a second hole 13, and a third hole. Hole 14 and a fourth hole 15 are provided. The third hole 14 is formed so that the distal end of the end 42 of the tube 41 can be inserted in a tightly contacted state.

At the inner end of the first hole 12, the first hole 12
An annular rib 21 protruding radially inward from the inner peripheral surface of the rim is press-fitted and fixed. The rib 21 is a boss-shaped annular projecting portion having a tapered outer peripheral surface 23a having a taper outer surface 23a whose diameter gradually decreases toward one end side at the center of a flange portion having an outer peripheral surface that can be fitted to the inner peripheral surface of the first hole 12. 23, and an insertion hole 22 in the center of which the end 42 of the tube 41 can be inserted is formed in the main body 1.
0 is provided concentrically. The rib 21 is provided in the first hole 1
The second hole 13 is fitted and fixed in contact with a radially extending annular surface adjacent to the second hole 13.

At one end of the main body 10 adjacent to the boss 21, a cylindrical holder 25 is provided. The holder 25 has a guide inner peripheral surface 26 that extends straight in parallel with the axis at one end side, and a regulating concave taper inner peripheral surface 27 that is adjacent to the guide inner peripheral surface 26 and gradually increases in diameter toward the other end.
have. The other end of the holder 25 is formed on a large-diameter inner peripheral surface 28 that extends straight from the large-diameter end of the regulating concave tapered inner peripheral surface 27 toward the other end of the holder 25. It is arranged concentrically on the outer periphery of the protrusion 23. The other end of the outer peripheral surface of the holder 25 is inserted into the first hole 12 of the main body 10, and the main body 1
It is fixed by caulking the entrance portion of 0 to the outer peripheral surface. Then, the regulating concave taper inner peripheral surface 27 and the rib 21
An annular recess 29 is formed between them.

In the second hole 13, an annular elastic sealing member 37 such as an O-ring is mounted. A coil spring 38 is abutted and fitted on a radially extending annular surface of the third hole 14 adjacent to the fourth hole 15.
The coil spring 38 has a length of about one turn. Further, the base end of a metal insertion tube member 39 capable of inserting the inner peripheral surface of the end portion 42 of the tube 41 is inserted into the fourth hole 15, and the holder 25 faces the one end side. And extend concentrically. A coil spring 38 inserted in the third hole 14 is externally fitted on the outer periphery of the insertion tube member 39.

As shown in FIG. 3, the fastening member 31 has a cylindrical base 32 at one end in the axial direction, has the same inner diameter as the inner peripheral surface of the base 32, and is spaced apart in the circumferential direction. Base 3
A plurality of elastically deformable arms 34 extending in the axial direction are provided by forming a plurality of cutouts 35 extending in parallel from the axis toward the other end in the axial direction. Further, a fastening portion 33 is formed integrally with the base portion 32 and the arm portion 34 at the free end side (the other end side) of the arm portion 34. Base 3
The outer diameter of the outer peripheral surface 2 is slightly smaller than the inner diameter of the guide inner peripheral surface 26 of the holder 25, and its outer peripheral surface is slidable on the guide inner peripheral surface 26. On the other hand, the inner peripheral surface 32 a of the base 32 is formed so that the distal end of the end 42 of the tube 41 can be inserted. Further, the fastening portion 33 has a head portion 33 a projecting radially outward from the arm portion 34 and abutting against the regulating concave tapered inner peripheral surface 27 of the holder 25, and a head portion 33 a.
a tube 4 protruding inward in the centripetal direction from a
1 and a claw portion 33b having a tip inner diameter smaller than the outer diameter.

The arm portion 34 is adjacent to the fastening portion 33 and extends in the axial direction toward one end.
And a thin portion 34b extending between the adjacent extended portion 34a and the cylindrical base portion 32. That is, the adjacent extension 34a
Has an outer diameter slightly larger than the outer diameter of the base 32, and the thin portion 34 b has an outer peripheral surface smaller in diameter than the outer diameter of the base 32.
Then, the fastening portion 33 of the fastening member 31 and the adjacent extension 3
4a is accommodated in the annular concave portion 29 so as to be movable in the axial direction. The annular fastening member 31 is held movably in the axial direction in the annular concave portion 29 and the guide inner peripheral surface 26.

Next, a method for connecting the end 42 of the tube 41 to the thus formed tube joint shown in FIG. 2 will be described. As shown in FIG. 4, the end 42 of the tube 41 is inserted from the open end of the base 32 of the fastening member 31 projecting outward from one end of the holder 25,
The inner peripheral surface of the tightening member 31, the insertion hole 22 of the rib 21, and the elastic seal member 37 are communicated with each other, and the distal end portion is inserted into the third hole 14. Further, the coil spring 38 is pushed at the tip of the end portion 42 of the tube 41, and the coil spring 38 is pressed against the radially extending annular surface adjacent to the fourth hole 15 to be compressed. At this time, in order for the outer peripheral surface of the tube 41 to pass through the claw portion 33b, it is necessary to forcibly expand the tightening portion 33 outward in the radial direction. Since there is a slight annular space between the holes, the fastening portion 33 can be easily expanded, and the end portion 42 of the tube 41 can be easily inserted into the innermost part of the third hole 14. At this time, the tube 41
Is sealed by an annular elastic seal member 37 interposed between the outer peripheral surface of the end portion 42 and the inner peripheral surface of the second hole 13.

Thereafter, when the tube 41 is slightly pulled back to one end in the axial direction, as shown in FIG. 5, the fastening member 31 is returned to one end together with the tube 41, and the head 33a of the fastening member 31 is regulated. While contacting the concave tapered inner peripheral surface 27, at least a part of the thick adjacent extension 34 a of the arm 34 is weakly engaged with the other end of the guide inner peripheral surface 26 of the holder 25, and the claw 33 b is connected to the tube. 41 weakly bites into the outer peripheral surface of the end 42. Thereafter, when fluid pressure acts on the tube joint, the tube 41 is further returned in one end direction, the head 33a moves in the centripetal direction along the regulating concave tapered inner peripheral surface 27, and the claw portion 33b is moved to the end of the tube 41. 42, and the extension 34a adjacent to the arm portion 34 of the tightening portion 33 is strongly engaged and held in the guide inner peripheral surface 26,
The bite is restricted to an appropriate bite so that the tube 41 is not cut off.

Note that a part of the adjacent extension 34a is
5 so that it can be smoothly inserted into the guide inner peripheral surface 26.
It is preferable to form an insertion outer peripheral surface chamfered into a convex tapered surface at the entrance of the adjacent extension 34a. Also, preferably,
By applying the annular protrusion 23 having the above-described tapered outer peripheral surface 23 a to the inner peripheral edge of the insertion hole 22 of the rib 21, the head of the tightening portion 33 is pressed when the tube 41 bit by the claw 33 b is pushed inward. 33a is the tapered outer peripheral surface 23
a, and the fastening portion 33 can be expanded. Therefore, the tube 41 can be detached from the fastening member 31, and the tube 41 can be easily removed from the main body 10.

Here, by slightly retracting the tube 41 as described above, the coil spring pressed against the radially extending surface of the third hole 14 adjacent to the fourth hole 15 by the tip of the tube 41. The compressed state of the tube 38 is relaxed, and the elastic force of the coil spring 38 causes a biasing force to act on the tube tip side.
Therefore, even when the tube joint is in a non-pressurized state, the state in which the claw 33b bites into the tube 41 is maintained, and even if vibration is applied to the tube joint and the tube 41 tries to move inward in the axial direction, Coil spring 3
The movement is hindered by the urging force of No. 8. That is, the state in which the tube 41 is tightened by the tightening member 31 is maintained.

For this reason, even if the moisture that has entered the inside of the holder 25 from the outside freezes due to a decrease in the outside temperature, the fastening member 3 is expanded by the volume expansion of the moisture caused by the freezing.
1 does not increase in diameter, and therefore, the function of tightening the tube 41 by the tightening member 31 does not decrease. As a result, even if moisture is frozen in one end of the body portion 10 of the tube joint, the tube 41 can be reliably prevented from being pulled out from the body portion 10 and the connection reliability of the tube joint can be improved.

If the length of the coil spring 38 is substantially one turn, the effect of urging the tube 41 can be obtained. Therefore, it is necessary to increase the length of the main body 10 by inserting the coil spring 38 as compared with the conventional case. There is no. In addition, by using the coil spring 38 having a small length, it is possible to reliably prevent the tube 41 from being pulled out from the main body 10 at low cost. Furthermore, since the short coil spring 38 can be supported by also using the insertion tube member 39 for reinforcing the tube 41, the coil spring 38 can be stably and inexpensively supported.

According to the present embodiment, the tube 41
Of course, the tightening member 31 is moved to one end together with the tube 41 when the tube 41 is pulled back, so that the arm portion 34 is relatively thick. The extended portion 34a and the thin portion 34b formed on the guide inner peripheral surface 26 are inserted into the guide inner peripheral surface 26, and the claw portion 33b engaged with the outer peripheral surface of the end portion 42 is formed in a relatively thick axial direction. The inserted tube 41 can be firmly fixed by the extending adjacent extension 34a and the thin wall 34b.

Therefore, even if a bending force is applied to the tube 41, the adjacent extension portion 34a and the thin portion 34b suppress the twisting at the base of the head portion 33a, and the claw portion 33b always keeps the end portion 42 of the tube 41. The tube 41 can be firmly fixed uniformly in the circumferential direction, and the tube 41 can be prevented from coming off. Also, even when the temperature of the engine room of the automobile changes and the tube 41 expands or returns to its original state, the tube 41 is always uniformly and firmly fixed in the circumferential direction even with the deterioration due to the temperature change acting on the tube. Can be
The tube 41 can be made hard to come off,
Can be fixed uniformly in the circumferential direction over a long period of time,
Thermal degradation performance can be improved.

In the above-described embodiment, as described above, the base end of the insertion tube member 39 that allows the inner peripheral surface of the end portion 42 of the tube 41 to be inserted into the fourth hole 15. Although it extends concentrically with the holder 25 toward one end, as another form, a flange-shaped flange portion having an outer diameter substantially equal to the inner diameter of the third hole 14 is formed at the base end portion of the insertion tube member. May be provided, and the insertion tube member may be fixed by press-fitting the flange portion into the third hole. Thereby, the flange also serves as a positioning portion of the coil spring 38. In this case, the third hole and the fourth hole may have the same inner diameter.

Although the main body shown in the above embodiment has a rectangular shape bent at a right angle, the present invention is not limited to this, and is a tube joint having a main body extending straight from one end to the other end. Is also good. Further, the tube joint of the present invention is not limited to the tube joint shown in the above embodiment, and can be connected by biting back the tube inserted into the shaft hole of the main body so as to bite into the claw portion of the tightening portion. Should be fine. Further, the tube joint of the present invention is applicable not only to automobiles but also to similar uses. In addition, the tube joint shown in the above embodiment is an example, and can be implemented in various forms without departing from the gist of the present invention.

[0030]

According to the first aspect of the present invention, even if the water that has entered the inside of the holder from the outside freezes, the diameter of the fastening member does not increase even if the volume due to the freezing expands.
Therefore, the action of the fastening member for fastening the tube does not decrease. As a result, even if moisture is frozen in one end of the main body of the tube joint, the tube can be reliably prevented from being pulled out, and the connection reliability of the tube joint can be improved.

If the length of the coil spring is approximately one turn, the effect of urging the tube can be obtained, so that it is not necessary to increase the length of the main body by inserting the coil spring as compared with the conventional case. Further, by employing a coil spring having a small length, it is possible to reliably prevent the tube from being pulled out from the main body at low cost (the effect of the invention of claim 2). Furthermore, since the short coil spring can be supported using the metal insertion tube member for reinforcing the tube, the coil spring can be stably and inexpensively supported (the effect of the invention of claim 3).

[Brief description of the drawings]

FIG. 1 is a partially broken front view showing a tube joint according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of the tube joint before tube connection.

FIG. 3 is a front sectional view showing a tightening member constituting the tube joint.

FIG. 4 is an enlarged front sectional view showing a main part of the tube joint in a state where a tube is inserted.

FIG. 5 is an enlarged front sectional view showing a main part in a state where a tube inserted into the tube joint is pulled back.

FIG. 6 is a cross-sectional view showing a tube joint as a conventional example with a lower half omitted.

FIG. 7 is an enlarged sectional view showing a main part of the tube joint before tube connection.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Body part, 10a ... 1st connection part, 11 ... Shaft hole, 12
... 1st hole, 13 ... 2nd hole, 14 ... 3rd hole, 15 ...
4th hole, 21 ... rib, 25 ... holder, 26 ... guide inner peripheral surface, 27 ... regulating concave taper inner peripheral surface, 31 ... fastening member,
32 base, 33 fastening part, 33a head, 33b
Claw part, 34 ... arm part, 37 ... elastic seal member, 38 ...
Coil spring, 39: insertion cylinder member, 41: tube, 42: end.

Claims (3)

[Claims] 1. A pre-assembled tube joint connectable by pulling back an inserted resin tube, the tube joint extending in an axial direction having an inner diameter gradually decreasing in diameter from one end to the other end. A shaft hole having a first hole, a second hole, a third hole, and a fourth hole, wherein the third hole is formed so that the end of the tube can be tightly inserted into the tube; A cylindrical main body, and an insertion hole through which an end of the tube can be inserted, and a radially inward portion of the first hole of the main body from an inner peripheral surface of the first hole. An annular rib integrally provided so as to protrude in the direction, an inner peripheral surface and an outer peripheral surface, and the inner peripheral surface is provided on one end side with a guide inner peripheral surface that extends straight parallel to the axis, A regulating concave taper inner peripheral surface having a diameter gradually increasing toward the other end adjacent to the guide inner peripheral surface on the other end side; An annular recess formed between an inner peripheral surface and the annular rib, and a cylindrical holder having at least the other end of the outer peripheral surface fixed in a first hole of the main body; and a cylindrical holder inserted in the second hole. An annular elastic seal member fitted therein, a coil spring inserted in the third hole, and a guide having an outer peripheral surface slidable on the guide inner peripheral surface of the holder at one end of a shaft hole. A plurality of elastically deformable formed by providing a cylindrical base having an outer diameter slightly smaller than the inner diameter of the inner peripheral surface and a circumferentially spaced notch extending from the base toward the other end in the axial direction Arm portion, a head arranged in an annular shape and integrally provided at a free end of each arm portion, protruding radially outward and abutting on the inner peripheral surface of the restricting concave taper, and centering from the head. Inside the distal end smaller than the outer diameter of the tube to be inserted An end portion of the tube, wherein the end portion of the tube comprises: a clamping portion having a claw portion having a clamping portion, the clamping portion being provided in the annular concave portion so as to be movable in the axial direction. When the coil spring is inserted into the third hole of the main body by inserting the coil spring into the third hole, the fourth hole in the third hole. The tube is pressed against a radially outwardly extending annular surface adjacent to the tube and compressed, and the space between the outer peripheral surface of the end of the tube and the inner peripheral surface of the second hole is sealed by the elastic sealing member. Is slightly retracted, the tightening member is moved to one end together with the tube, the head of the tightening member abuts the inner peripheral surface of the restricting concave taper, and the head is Move in the centripetal direction along the inner circumference A tube joint, wherein the claw portion is moved to engage with an outer peripheral surface of an end portion of the tube, and the tube is urged axially toward one end by the coil spring. 2. The tube joint according to claim 1, wherein the coil spring has a length of substantially one turn. 3. One end of the tube is inserted and fixed in the fourth hole, and the other end is extended in the direction of the first hole. A tube inserted into the shaft hole can be inserted around the outer periphery of the one end. The tube joint according to claim 1 or 2, wherein a metal tubular insertion tube member is provided, and the coil spring is inserted around an outer periphery of the insertion tube member.