JP2510931B2 - Branching equipment for plastic pipes - Google Patents

Abstract

PURPOSE:To provide a method and a device for branching and connecting a plastic pipe having a small diameter with satisfactory air-tightness without using a joint. CONSTITUTION:A saddle-like flared part 4 have been integrally incorporated with a plastic branch pipe 2 at one end of the latter, and is adapted to be vibrated in the longitudinal direction of a plastic main pipe 1 having an opening 3 in its side wall, in such a condition that the flared part 4 is made into press contact with the main pipe 1. The joint device comprises a lower die having a channel, an upper die having a cavities including a recess and a hole part, and a vibration source for vibrating the upper die crosswise, and the main pipe 1 is set in the channel while the branch pipe 2 is set in the cavity, and the flared part 4 is made into press contact with the periphery of the opening 3 of the main pipe 1. In this condition, the upper die is vibrated crosswise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branching and joining apparatus for plastic pipes, and more particularly to a branching and joining apparatus for plastic pipes that can be joined securely and airtightly without using a joint.

[0002]

2. Description of the Related Art In a piping system through which a fluid such as a gas or a liquid is passed, it is necessary to provide a branch joint for dividing or joining the liquid.

Conventionally, a T-joint has been used to provide a branch joint in a plastic pipe, and the T-joint has been inserted into the plastic pipe. For example, in the case of a pipe for supplying gasoline to an engine, conventionally, a pipe made of a branched metal joint and a rubber pipe for joining the joint has been used. However, since such a gasoline supply pipe has a complicated structure, there is a problem that the manufacturing cost is high and the rubber pipe portion is cracked to cause leakage of gasoline.

There is also a case where an opening portion is provided on the side wall of the main pipe, and the end portion of the branch pipe is brought into contact with the opening portion to be bonded with an adhesive, or a welding method using a welding rod made of the same material is used.

[0005]

However, in the joining method using the T-joint, the joint occupies a large space, and it is difficult to install several pipes in a narrow place such as an engine room of an automobile. Also, since the flow path changes abruptly, it becomes difficult to control the flow velocity and flow rate of the fluid. In addition, such a joint is generally expensive and requires a lot of man-hours for the joining work, so that the joining cost is high.

In addition, in the joining method by abutting, the joining strength is weak and the reliability against airtightness is low, so that gas or liquid may leak from the joining portion. In addition, if the diameter of the pipes to be joined is small, it is almost impossible to form the airtight joint.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a branch joining device having good airtightness, which can be formed easily and reliably even on a plastic pipe having a small diameter without using a joint.

[0008]

As a result of earnest research in view of the above object, the present inventor has found that a saddle-shaped flare portion is integrally formed on an end portion of a plastic branch pipe and is provided on an outer surface of the plastic main pipe. By abutting on the main pipe so as to wrap around the opening, and applying vibration in the longitudinal direction of the main pipe,
The present invention was discovered by discovering that the branch pipe can be firmly fused to the main pipe.

That is, the branching and joining apparatus for a plastic pipe of the present invention is a plastic main pipe having an opening on the side wall.
For joining a plastic branch pipe having a flare portion as a branch, (a) a lower mold having a groove portion that partially accommodates the side wall of the main pipe, and (b) an inner surface shape substantially corresponding to the outer surface shape of the flare portion. An upper mold having a cavity composed of a concave portion having a hole and a hole having a diameter for accommodating the branch pipe, which communicates with the concave portion, and (c) a vibration source that gives lateral vibration to the upper mold, The hole of the cavity is of the upper mold.
It is open to the side surface, the main pipe is housed in the groove of the lower mold, the branch pipe is housed in the hole of the cavity of the upper mold, and the flare portion is pressed against the periphery of the opening of the main pipe. In this state, the contact is welded by frictional heat by operating the vibration source to vibrate the upper mold in the lateral direction.

[0010]

In the apparatus for branching and joining a plastic pipe of the present invention, a saddle-shaped flare portion is integrally formed at the end of the plastic pipe (branch pipe) that abuts the joint portion, and the saddle-shaped flare portion is formed. The end face is pressed against the plastic main pipe so as to wrap the outer surface, and vibration is applied in the longitudinal direction of the main pipe in that state, so the joint part around the opening welds and the branch pipe is fixed to the main pipe in a sealed state. can do.

At this time, unlike the ultrasonic welding method, since the vibration direction is the lateral direction (longitudinal direction of the main pipe), the friction energy between the outer surface of the main pipe and the inner surface of the flare portion becomes very large. Therefore, the interface between both members is easily melted and fused.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A branch joint of a plastic pipe of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of a branch joint portion of the plastic pipe of the present invention. An opening 3 having a diameter substantially equal to the inner diameter of the plastic pipe (branch pipe) 2 is formed in the side wall of the plastic pipe (main pipe) 1, and a saddle-shaped flare portion 4 is integrally formed at the end of the plastic branch pipe 2. Is formed in. Since the end surface of the saddle-shaped flare portion 4 has a shape that partially encloses the outer surface of the plastic main pipe 1, when the plastic branch pipe 2 is brought into contact with the side wall of the plastic main pipe 1 as shown in FIG. , The saddle-shaped flare part 4 is the plastic main pipe 1
Snugly engages the outer surface of the.

The plastic pipe which can be used in the present invention is a thermoplastic such as polyolefin such as polyethylene and polypropylene, polyamide such as nylon, polystyrene, polyvinyl chloride, polybutylene terephthalate, modified polyphenylene oxide, polycarbonate, polyacetal and the like. It is plastic. Polyamides such as nylon 11 and nylon 12 are particularly preferred for automobile-related plastic pipes that require chemical resistance at high temperatures.

Thermoplastics can be plastically deformed by an external heat source such as a heater. For example, when an attempt is made to form a flare portion, the periphery of the end of the plastic pipe is melted in a fairly wide range, so that a saddle-shaped flare portion is formed. It is difficult to control the shape of the tube, and the tube hole may be narrowed.

Therefore, as means for locally softening and melting the plastic pipe so as to plastically deform it without melting it in a wide range, ultrasonic welding, high frequency welding, vibration welding, etc. are preferable.

In the case of the ultrasonic welding method, the horn of the ultrasonic welding machine has the same shape as the outer surface of the main pipe, and ultrasonic waves having a frequency of 15 to 30 KHz are irradiated for 0.3 to 10 seconds while pressing the horn against the end face of the branch pipe. Then, a saddle-shaped flare portion is formed by plastic deformation. Further, the end surface of the saddle-shaped flare portion is formed to have the same outer surface shape as the plastic tube with which the saddle-shaped flare portion abuts, and the tube hole is not substantially narrowed.

Also in the case of the high frequency welding method, similarly, the electrode is pressed against the end of the plastic tube and a high frequency of 10 to 50 MHz is irradiated for 0.5 to 30 seconds to form a saddle-shaped flare portion.

The saddle-shaped flare portion 4 formed by the above method is joined to the peripheral portion of the opening 3 of the main pipe 1 by the vibration welding method.

The apparatus shown in FIG. 3 is used for the vibration welding method. This apparatus has a lower mold 10 having a groove 10a for accommodating the plastic main pipe 1 in a laid state, and an upper mold 11 having a cavity 12 for accommodating a plastic branch pipe 2 having a flare portion 4 in the axial direction. The cavity 12 of the upper mold 11 is composed of a concave portion 12a having an inner surface shape corresponding to the outer surface shape of the flare portion 4, and a cavity 12b located in the central portion of the concave portion 12a and extending in the vertical direction. A vibration source (not shown) for vibration welding is fixed to the upper mold 11.

To perform vibration welding, as shown in FIG.
The plastic main pipe 1 is installed in the groove 10a of the lower mold 10 with the opening 3 facing upward, and the plastic branch pipe 2 is inserted into the cavity 12 of the upper mold 11. At this time, the opening 3 of the main pipe 1 installed in the lower mold 10 and the upper mold 1
The main pipe 1 is positioned so that the flare portion 4 of the branch pipe 2 inserted into the pipe 1 is aligned. Further, in order to prevent the deformation of the main pipe 1, it is preferable to insert a round bar into the main pipe 1.

In this state, either the lower mold 10 or the upper mold 11 is moved up and down to press the flare portion 4 of the branch pipe 2 around the opening 3 of the main pipe 1. Since the recess 12a of the upper mold 11 has an inner surface shape that is substantially the same as the outer surface shape of the flare portion 4, the pressure contact force of the flare portion 4 with respect to the main tube 1 is substantially uniform. Generally, the pressure contact force is preferably ²⁰ to 600 kg / cm ² .

In this state, the upper mold 11 is vibrated by a vibration source (not shown). The vibration source is an electromagnetic drive type, the vibration frequency is 100 to 500 Hz, and the amplitude is 0.2 to 3
mm. The vibration direction is a direction in which the bonding interface slides, and specifically, is the longitudinal direction of the main pipe 1 due to the shape of the flare portion 4. Under such conditions, the vibration welding time is generally 0.5 to 5 seconds.

When the plastic branch pipe 2 is sufficiently short, as shown in FIG.
However, if the branch pipe 2 is very long, it cannot be accommodated in the cavity 12. Therefore, the upper mold 11 having the cavity 12 having the shape shown in FIG. 6 is used.
In this upper mold, the cavity 12 is curved so that the upper mold 1
1 is open to the side surface, and the extension of the branch pipe 2 is exposed to the outside through the opening. By using the upper mold 11 having such a structure, the branch pipe 2 of any length can be accommodated.

The branch joining device of the present invention can be applied to plastic pipes of arbitrary diameters, but is particularly effective for plastic pipes of small diameters for which it is not preferable to use a joint or abutting and joining. Specifically, the outer diameter is 3 to 20 mm
The effect is great when branching plastic pipes of a certain degree.

FIG. 7 shows an example of a gasoline supply pipe formed by a plastic pipe joined by the branch joining device of the present invention. In this gasoline supply pipe, a plurality of branch pipes 2 are joined to the main pipe 1 by the branch joining device of the present invention, and the main pipe 1 is bent into a desired shape after joining the branch pipes. With such a method, a gasoline supply pipe of any shape can be easily and surely formed. Also,
Since the resulting gasoline supply pipe has a minimum number of joints, there is no problem such as leakage of gasoline.

The present invention will be described in more detail with reference to the following specific examples. Example 1 Nylon 11 outer diameter 6.4 mm, inner diameter 4.4 mm
In order to branch-join a main pipe of the same size and the same material to the main pipe, an opening with a diameter of 4 mm is formed by machining on the side wall of the main pipe, and the end face of the main pipe has an end surface having the same shape as the outer surface of the main pipe. The saddle-shaped flare portion was formed by an ultrasonic welding machine. The diameter of the saddle-shaped flare portion was approximately 10.4 mm.

A 4.2 mm round bar was placed inside the main tube.
These main pipe and branch pipe were housed in the lower mold and the upper mold of FIG. 3, respectively, and pressure-welded at a pressure of 160 kg / cm ² . In addition,
The pressure contact force was calculated by determining the load applied to the pipe from the gauge pressure of the air cylinder used and the cylinder diameter, and dividing by the area of the flare portion. In that state, frequency 240 Hz, amplitude 1
mm sliding was applied for 1 second, and vibration welding was performed.

When the joint strength of the thus-obtained plastic main pipe with branch pipe was measured, it broke from the portion other than the joint portion and showed a joint strength higher than that of the plastic pipe body.
Further, water having an internal pressure of 50 kg / cm ² was passed through the inside of the branch pipe, but no leakage was observed at the branch joint. Furthermore, it was found that a stable bonding strength can be obtained by putting a round bar inside the main pipe.

The present invention has been described with reference to the above embodiments.
The present invention is not limited to this, and various modifications can be made within the scope of the idea of the present invention.

[0031]

As described above, by welding the flare portion of the plastic branch pipe in which the saddle-shaped flare portion is formed in advance to the plastic main pipe in which the opening portion is formed, by the vibration welding method, Branch joints can be performed on plastic pipes of any thickness. If the branch joining device of the present invention is used, it is not necessary to use an adhesive or to heat, so that welding is easy and there is no joint failure, and a branch pipe of any aspect is surely welded to the main pipe. You can The branch joining method of the present invention having the above characteristics is particularly effective for a plastic pipe having a small diameter.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a branch joint portion of a plastic pipe to which a branch joining method of the present invention is applied.

FIG. 2 is a perspective view showing a joined state of the branch joining portion of FIG.

FIG. 3 is a schematic sectional view showing a branch joining device of the present invention.

4 is a cross-sectional view showing a state in which a plastic pipe is attached to the branch joining device of FIG.

FIG. 5 is a cross-sectional view showing a state in which the branch joining device is clamped.

FIG. 6 is a partial cross-sectional view showing a branch joining device according to another embodiment of the present invention.

FIG. 7 is a schematic view showing an example of a gasoline supply pipe formed by the branch joining method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... ・ Plastic main pipe 2 ・ ・ ・ Plastic branch pipe 3 ・ ・ ・ ・ Aperture 4 ・ ・ ・ ・ Saddle-shaped flare portion 10 ・ ・ ・ Lower mold 10a ・ ・ ・ Main pipe groove 11 ・... Upper mold 12 ... Cavity 12a ... Recess 12b ... Hole

Claims (2)

(57) [Claims] 1. An apparatus for joining a plastic main pipe having a flare portion to a plastic main pipe having an opening in a side wall as a branch, comprising: (a) a lower mold having a groove partly accommodating the side wall of the main pipe; (B) an upper mold having a cavity having an inner surface shape substantially corresponding to the outer surface shape of the flare section, and a cavity communicating with the recess section and having a diameter of a diameter for accommodating the branch pipe; and (c) the upper section. And a vibration source for applying a lateral vibration to the mold, wherein the hole of the cavity is
The main mold is opened in the side surface of the upper mold, the main pipe is housed in the groove of the lower mold, the branch pipe is housed in the hole of the cavity of the upper mold, and the flare portion is formed in the opening of the main pipe. A branch joining device for a plastic pipe, wherein a contact portion is welded by frictional heat by operating the vibration source to laterally vibrate the upper mold while being pressed against the surroundings. 2. The branch of the plastic pipe according to claim 1.
In the joining device, the hole of the cavity is curved and
A plastis characterized by being opened on the side surface of the above-mentioned die
Branch joint device for check pipe.