JP2003166685A - Joint connecting flexible tube consisting of thermoplastic resin material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve sealing performance between a flexible tube and a joint with a simple structure in a joint rotatably welding a flexible tube without buckling or twisting the flexible tube. <P>SOLUTION: This joint comprises a cylindrical main body 30 and a cylindrical connecting part 40 integrally formed in a tapered shape at one end of the main body 30, and a flexible tube 10 made of nylon is connected with the connecting part 40. A plurality of circular projections 41a having outer radius larger than the inner radius of the flexible tube 40 are disposed on the outer peripheral surface of the connecting part 40 connected with the inner peripheral surface of the flexible tube 10 along the axial direction. The connecting part 40 is pressure-fitted into the flexible tube 10 while relatively rotating the main body 30 and the flexible tube 10 around the central axis to be mutually welded. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint in which a flexible tube made of a thermoplastic resin material is welded by press-fitting while relatively rotating, that is, rotary welding.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a cylindrical main body 1 and a flexible tube 3 integrally provided at one end of the main body 1 and made of a thermoplastic resin material (for example, nylon material). There is known a pipe joint provided with a tapered cylindrical connecting portion 2 for connecting the above. On the outer peripheral surface of the connecting portion 2,
A plurality of annular protrusions 2 a having an outer diameter larger than the inner diameter of the flexible tube 3 and an annular recess 2 b to which the O-ring 4 is attached are formed. The flexible tube 3 is press-fitted into the connecting portion 2. A metal pipe 5 is inserted inside the other end of the main body 1 and is detachably locked.

In such a pipe joint, by utilizing the elastic force of the O-ring 4 and the flexible tube 3 at the time of deformation, the space between the outer peripheral surface of the connecting portion 2 and the inner peripheral surface of the flexible tube 3 is made. It is sealed. That is, in the O-ring 4, the once contracted O-ring 4 is in liquid-tight contact with each other due to the elastic force to return to the original shape and the elastic force to expand the flexible tube 3 to contract. Convex part 2
In a, the flexible tube 3 that has once expanded is in liquid-tight contact with each other due to the elastic force that tends to contract. In this case, there is a problem that the elastic force is weakened due to the change with time of the flexible tube 3, environmental conditions (for example, environmental temperature), etc., so that the flexible tube 3 may rotate or may easily come off.

[0004]

Therefore, there has been a demand for a connection structure (connection method) that solves such a problem. As a method of coping with this, as shown in Japanese Patent Laid-Open No. 56-20888, nylon coating is applied to the tapered portion of the die, and the tapered portion is press-fitted into the nylon tube while rotating the die to weld them together. There is a way to do it.

However, in this method, in order to maintain a high sealability between the nylon tube and the pipe joint, it is necessary to increase the joint area of these joint portions, while increasing the joint area, Since the frictional resistance between both members becomes large and the rotational load becomes large, the flexible tube may be buckled or kinked.

The present invention has been made to solve the above problems, and its purpose is to prevent a flexible tube from buckling or twisting in a pipe joint in which a flexible tube is rotationally welded. , Maintaining a high sealing property between the flexible tube and the pipe joint with a simple structure.

[0007]

SUMMARY OF THE INVENTION (Means for Solving the Problems and Actions / Effects of the Invention) In order to achieve the above object, a structural feature of the present invention is that a cylindrical main body and one end of the main body are integrally formed. A tapered cylindrical connecting part for connecting a flexible tube made of a thermoplastic resin, and the connecting part while rotating the main body and the flexible tube relatively around the central axis. In a pipe joint that is welded to each other by press-fitting into a flexible tube, an outer diameter larger than the inner diameter of the flexible tube is formed on the outer peripheral surface of the connecting portion that joins with the inner peripheral surface of the flexible tube. This is because a convex portion extending in the circumferential direction is provided.

According to this, when the relatively rotating connecting portion is press-fitted into the flexible tube, the connecting portion has a diameter larger than the inner diameter of the flexible tube, that is, at least the connecting portion. The portion near the top of the provided convex portion is joined to the inner peripheral surface of the flexible tube. Thus, conventionally, almost the entire outer peripheral surface of the connecting portion is joined to the inner peripheral surface of the flexible tube and is joined to each other at the wide band-shaped surface. It is possible to join at a narrow portion (near the top of the convex portion). Therefore,
By reducing the area of the joint, the frictional resistance at the joint can be kept small, so the rotational load can be kept small, and the flexible tube is prevented from buckling or kinking. be able to.

Further, since the surface pressure at the joint can be increased by reducing the area of the joint, the joint on the inner peripheral surface of the flexible tube can be reliably melted.
Then, after the completion of the rotational press-fitting described above, since this fusion portion is surely welded near the top of the convex portion provided in the connection portion,
It is possible to maintain high sealing performance at the joint between the flexible tube and the pipe joint.

Further, a plurality of annular projections provided along the axial direction are adopted as the projections of the present invention, and the outer diameter of each apex of these annular projections increases with increasing distance from the tip of the connecting portion. It is preferable to set as follows. According to this, since the joint portion continuous in the circumferential direction of the flexible tube, that is, the annular joint portion is provided, it is possible to further improve the sealing property of the joint portion between the flexible tube and the pipe joint. it can. Further, since the annular joint portion is provided in multiple layers in the axial direction, it is possible to further improve the sealing property of the joint portion between the flexible tube and the pipe joint. Moreover,
The sealability of these annular joint portions increases as the distance from the tip of the connecting portion increases.

Further, it is preferable that the annular concave portions formed by the adjacent annular convex portions of the present invention are set so as to become deeper as the distance from the tip of the connecting portion increases. According to this, in addition to the above-described action and effect, since the scraps generated on the inner peripheral surface of the flexible tube during the rotary welding are accommodated in the annular recess, the scraps are not generated after the rotary welding. Since the time and effort to remove it can be omitted, the connection time can be shortened as a whole.

Further, it is preferable to employ a spiral convex portion as the convex portion of the present invention. According to this, in addition to the above-described action and effect, the spiral convex portion provided in the joint portion further enters while threading the inner peripheral surface of the flexible tube, so that the connection portion smoothly enters the flexible tube. Since it is inserted, the press-fitting time can be shortened.

Further, it is preferable that a material that melts with the thermoplastic resin material is applied to the outer peripheral surface of the connecting portion joined to the inner peripheral surface of the flexible tube of the present invention. According to this, the sealing property between the flexible tube and the connecting portion can be further enhanced.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 (a) shows a pipe joint according to the present invention, and FIG. 1 (b) shows a flexible joint. 1C shows a state in which a flexible tube is connected, and FIG. 1C shows a state in which a metal pipe is further connected.

This pipe joint is made of a thermoplastic resin material (for example,
A cylindrical body 30 for joining a flexible tube 10 made of a nylon material and a metal pipe 20.
And a cylindrical connecting portion 40 integrally formed at one end of the main body 30 and formed in a tapered shape.

The flexible tube 10 is connected to the connecting portion 40, and the outer surface of the connecting portion 40 joined to the inner peripheral surface of the flexible tube 10 has an outer diameter of the flexible tube 10.
Is provided with a convex portion 41 which is larger than the inner diameter of and extends in the circumferential direction. Specifically, the convex portion 41 is annular, and a plurality of annular convex portions 41a are provided along the axial direction. That is, the outer peripheral surface of the connection portion 40 is continuously formed with irregularities having a triangular cross section. The outer diameter of the top of each of the annular convex portions 41a is set to increase as the distance from the tip of the connecting portion 40 (the left end in FIG. 1) increases.

In this embodiment, the connecting portion 4
Although the irregularities having a triangular cross section are continuously formed on the outer peripheral surface of 0, the invention is not limited to this, and the irregularities having a rectangular cross section may be continuously formed. In addition, each annular convex portion 41a
It is preferable to set the angle of the inclined surface on the distal end side of (1) to an angle (for example, 15 degrees to 45 degrees with respect to the central axis of the connecting portion 40) in consideration of the ease of passage of the flexible tube 10. Further, a tapered portion (in the present embodiment, a tapered portion is formed on the outer peripheral surface of the connecting portion 40 with which the inner peripheral end of the flexible tube 10 first comes into contact.
It is preferable to form an inclined portion on the front end side of the first convex portion 41 from the left. As a result, the inner peripheral end of the flexible tube 10 can be smoothly inserted without being caught by the outer peripheral surface of the connecting portion 40.

Further, as shown in FIG. 1 (c), the main body 30
Two O-rings 31 and 32 are attached to the center of the inside by a O-ring support member 34 with the annular spacer 33 interposed therebetween. In the O-ring support member 34, the annular concave portion 34 a provided on the outer peripheral surface has the annular convex portion 3 provided on the inner peripheral surface of the main body 30.
It is locked inside the main body 30 by engaging with 0a. This prevents the O-rings 31 and 32 from coming off the inside of the main body 30. A locking member 35 having a C-shaped cross section is detachably attached to the outer peripheral surface of the other end of the main body 30. A pair of claws 35a are provided on the inner peripheral surface of the locking member 35 so as to face each other, and a pair of openings 30b are provided at the other end of the main body corresponding to both claws 35a. As a result, when the metal pipe 20 is inserted to a predetermined position inside the main body 30, the two pipes 35 are liquid-tightly connected by the two O-rings 31 and 32 and the both claws 35a are connected to each other by the metal pipe 20.
It is attached by engaging with an annular flange 21 provided on the outer peripheral surface of the.

The process of attaching the flexible tube 10 to the above-mentioned pipe joint will be described. First flexible tube 1
0 is attached to the fixing device and fixed. Next, the flexible tube 1 described above is attached while the pipe joint is attached to the rotary moving device and is rotated at high speed around the central axis (for example, 1000 rpm).
It is moved toward 0 and the rotating connecting portion 40 is press-fitted into the flexible tube 10. At this time, a portion of the connecting portion 40 having a diameter larger than the inner diameter of the flexible tube 10, that is, at least a portion near the top of the annular convex portion 41 a provided in the connecting portion 40 is the inner peripheral surface of the flexible tube 10. It will be joined. That is, they are joined at a narrow band-shaped surface near the top of the annular convex portion 41a. Then, due to the relative rotation, the joint portion of the inner peripheral surface of the flexible tube 10 is melted by friction with the annular convex portion 41a.

When the connecting portion 40 of the pipe joint is inserted to a predetermined position while being relatively rotated, the movement in the axial direction is stopped, and then the rotation of the pipe joint is stopped. Then, when left for a while, the melted portion on the inner peripheral surface of the flexible tube 10 is solidified and the tube 10 and the connecting portion 40 are welded to each other. In the present specification, rotating and welding the flexible tube 10 made of the above-mentioned thermoplastic resin material by press-fitting the flexible tube 10 into the connecting portion 40 of the pipe joint while relatively rotating the same is referred to as rotary welding.

As can be understood from the above description, in this embodiment, when the connecting portion 40 of the relatively rotating pipe joint is press-fitted into the flexible tube 10, of the connecting portions 40, A portion having a diameter larger than the inner diameter of the flexible tube 10, that is, an annular convex portion 4 provided at least in the connecting portion 40.
A portion near the top of 1a is joined to the inner peripheral surface of the flexible tube 10. As a result, conventionally, the connecting portion 40
The entire outer peripheral surface of the is joined to the inner peripheral surface of the flexible tube 10,
The wide band-shaped surfaces are joined to each other, but a portion (annular convex portion 41a) having a width sufficiently narrower than the joined surface is used.
(Near the top of the). Therefore, by reducing the area of the joint portion, the frictional resistance at the joint portion can be kept small, so that the rotational load can be kept small, so that the flexible tube 10 is buckled or twisted. Can be prevented.

Since the surface pressure at the joint can be increased by reducing the area of the joint, the joint on the inner peripheral surface of the flexible tube 10 can be reliably melted. Then, after the above-described rotary press-fitting is completed, this fusion portion is surely welded to the vicinity of the top of the annular convex portion 41a provided in the connection portion, so that the joining portion 4 of the flexible tube 10 and the pipe joint is formed.
The sealing property of 0 can be maintained high. Therefore, it is possible to eliminate the O-ring that has been conventionally used, so that it is possible to suppress an increase in cost.

An annular convex portion 41 is formed on the outer peripheral surface of the connecting portion 40.
By providing a, a joint portion that is continuous in the circumferential direction of the flexible tube 10, that is, an annular joint portion is provided, so that the joint portion between the flexible tube 10 and the connecting portion 40 of the pipe joint is The sealing property can be further improved. Further, by providing a plurality of the annular convex portions 41a along the axial direction, the annular joint portions are provided in multiple layers in the axial direction, so that the connecting portion 4 between the flexible tube 10 and the pipe joint is formed.
It is possible to further improve the sealing property of the joint portion with 0. In addition, the outer diameter of the top of each of the annular convex portions 41a increases as the distance from the tip of the connecting portion 40 increases, while the flexible tube 10 increases in elastic force as it expands. The annular joint portion has a sealing property that increases as the distance from the tip of the connecting portion 40 increases.

In the above-described embodiment, as shown in FIG. 2, the annular concave portion 42 formed by the adjacent annular convex portions 41a is set to become deeper as it goes away from the tip of the connecting portion 40. You may do it. According to this, since the scrap generated from the inner peripheral surface of the flexible tube 10 during the so-called rotary welding described above is accommodated in the annular recess 42, after the rotary welding, the flexible tube 10 or the pipe is cut. Since it is possible to save the trouble of removing the scraps protruding to the outside of the joint, it is possible to shorten the connection time as a whole.

Further, in the above-described embodiment, the connecting portion 4 of the pipe joint that is joined to the inner peripheral surface of the flexible tube 10 is used.
A material that melts with a nylon material may be applied to the outer peripheral surface of No. 0. According to this, the sealing property between the flexible tube and the connecting portion can be further enhanced.

Further, in the above-mentioned embodiment, the nylon material is used as the thermoplastic resin material, but the present invention is not limited to this, and other thermoplastic resin material having a melting point that melts by frictional heat due to rotation is used. be able to.

Further, in the above-described embodiment, the annular convex portion 41a is provided on the outer peripheral surface of the connecting portion 40 as the convex portion 41 extending in the circumferential direction, but instead of this, FIG.
As shown in (a), a spiral convex portion 41b may be provided on the outer peripheral surface of the connecting portion 40. According to this, in addition to the above-described actions and effects, when the flexible tube 10 is further press-fitted into the connecting portion 40 provided in the pipe joint, the joining portion 40
Since the spiral convex portion 41b provided on the inside enters while cutting the inner peripheral surface of the flexible tube 10, the connecting portion 40 can be smoothly inserted into the flexible tube 10 and the press-fitting time can be shortened. can do.

In the attaching process of the above-mentioned embodiment, the flexible tube 1 which is positioned and fixed is fixed.
0, the connecting portion 40 of the pipe joint rotating around the central axis
Was moved and press-fitted, but while the pipe joint was attached to the rotating device and rotated at high speed around the central axis, the flexible tube 10 was moved in the axial direction and press-fitted into the rotating connecting portion 40. You may do it.

[Brief description of drawings]

1A is a diagram showing a pipe joint according to the present invention, FIG. 1B is a diagram showing a state in which a flexible tube is connected to the pipe joint, and FIG. It is the figure which showed the state which connected the pipe.

FIG. 2A is a diagram showing a pipe joint according to a modification of the present invention, and FIG. 2B is a diagram showing a state in which a flexible tube is connected to the pipe joint.

FIG. 3A is a diagram showing a pipe joint according to a modified example of the present invention, and FIG. 3B is a diagram showing a state in which a flexible tube is connected to the pipe joint.

FIG. 4A is a diagram showing a state in which a flexible tube and a metal pipe are connected to a pipe joint according to a conventional technique, and FIG. 4B is a diagram showing a state in which a metal pipe is connected to a pipe joint according to the conventional technique. It is the figure which showed the state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Flexible tube, 20 ... Metal pipe, 30 ... Main body, 40 ... Connection part, 41 ... Convex part, 41a ... Annular convex part, 4
1b ... spiral convex part, 42 ... annular concave part, 31, 32 ... O-ring, 33 ... annular spacer, 34 ... O-ring support member,
35 ... Locking member.

Continued front page    (72) Inventor Koji Miwa             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 3H017 DA00                 3H019 GA06                 4F211 AD12 AD24 AG08 AH11 TA01                       TC11 TD01 TH17 TN20

Claims (5)

[Claims] 1. A cylindrical main body, and a tapered cylindrical connecting portion integrally provided at one end of the main body to connect a flexible tube made of a thermoplastic resin material, In a pipe joint adapted to be welded to each other by press-fitting the connecting portion into the flexible tube while relatively rotating the main body and the flexible tube around the central axis,
A pipe joint characterized in that a protrusion extending in the circumferential direction having an outer diameter larger than the inner diameter of the flexible tube is provided on the outer peripheral surface of the connecting portion joined to the inner peripheral surface of the flexible tube. 2. A plurality of annular projections provided along the axial direction are adopted as the projections, and the outer diameter of each apex of these annular projections increases with increasing distance from the tip of the connecting portion. The pipe joint according to claim 1, wherein the pipe joint is set to. 3. The pipe joint according to claim 2, wherein the annular concave portion formed by the adjacent annular convex portions is set so as to become deeper as the distance from the tip of the connecting portion increases. 4. The pipe joint according to claim 1, wherein a spiral convex portion is adopted as the convex portion. 5. The material according to claim 1, wherein a material that melts with the thermoplastic resin material is applied to the outer peripheral surface of the connecting portion that is joined to the inner peripheral surface of the flexible tube. The pipe joint as described in 1 above.