JPH11400A - Pipe processing method and apparatus - Google Patents

Abstract

(57) [Problem] To provide a method of processing a pipe member by pressing from outside, in which the pipe member is pressed uniformly from the outer periphery, and the amount of pressing can be easily controlled. SOLUTION: A thermal expansion material is arranged on the outer periphery of a tube member, the material is expanded by heating, and the tube member is processed by the expansion force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for surface treatment or joining of relatively thin and thin tubes such as catheters.

[0002]

2. Description of the Related Art Heat sealing is well known as a typical method of heat welding a film. In this method, the overlap of the film made of thermoplastic resin is pressed against the heated material,
It melts the part that is in contact with the heated object, and realizes stronger welding at the melting interface by the pressing force.

[0003] A similar method has been used in the processing of pipes. Similar to the film, a semi-cylindrical cut mold was sandwiched from two directions to realize a pressing force. However, when pressure is applied to a cylindrical member such as a tube from two simple directions such as heat sealing, a compression force is obtained in the direction of the movement axis of the mold, but the compression force is not perpendicular to the movement axis. I can't get it.

In the processing of a tube, it is necessary to apply a force from the entire circumference of the tube toward the central axis, but such a force cannot be realized by a method such as heat sealing.

[0005]

Several methods have been proposed to solve these problems. First,
As a method of using a mold, a method of obtaining a compression force from the entire circumference by inserting a pipe to be machined into a mold that has been cut into a tapered shape in advance and pressing the machined part so as to contact the tapered part of the mold (JP-A-2-194925, JP-A-3-
184564) has been proposed. However, due to the principle of pressing against the tapered mold wall surface, there is a drawback that the compression location is point contact and that a wide area cannot be uniformly compressed. Furthermore, one of the compression parts has to pass through a small diameter part of a tapered mold, and for example, has a disadvantage that machining at the center of a straight pipe part is practically impossible.

Subsequently, the pipe to be machined is pulled in the axial direction into a half mold having an inner hole smaller than the outer diameter of the pipe to be machined, temporarily made smaller than the inner hole of the mold, and the above-mentioned metal mold is formed. A method has been proposed in which, after the mold is set, the tension in the axial direction is released to obtain a reactive pressure (JP-A-6-335530). However, it is necessary to pull the tube to make it smaller than the inner hole of the mold, and there is a drawback that it cannot be applied to a tube that is difficult to stretch or a tube that has a characteristic that cannot be restored to its original shape while being deformed. In addition, since processing is performed only with the reaction force of the pipe, it is not suitable for processing that requires sufficient force,
In the above method, press from inside the tube to the outside mold 2
The following operation is also added, and there is a disadvantage that the operation is complicated.

As another method, there has been proposed a method of covering a heat shrinkable tube of another kind and obtaining a compressive force by the shrinkage force (JP-A-3-280968 and JP-A-6-91006). However, it is not easy to uniformly shrink the heat-shrinkable tube without uneven shrinkage. In addition, the operation of cutting the tubular heat-shrinkable tube to the required length and setting it at the joint, and the heat-shrinkable tube that has become unnecessary after processing It is difficult to automate a series of operations to cut and remove the heat-shrinkable tube, and it is extremely difficult to cut and remove the heat-shrinkable and closely adhered heat-shrinkable tube from the processed part without damaging the tube. It is. In addition, the cut heat-shrinkable tube has a drawback that it cannot be reused, and a drawback that the shrinkage force in heat shrinkage is weak and a sufficient compressive force cannot be obtained. Furthermore, the technology of controlling the heat shrink function so that only the target portion has the desired shape is very difficult, and such a heat shrink tube has not been realized.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of processing a tube member by pressing the tube member from the outer periphery. A pipe processing method characterized by expanding by heating and processing a pipe member by the expansion force.

[0009] The present invention also provides a pipe processing apparatus characterized by comprising a thermal expansion material disposed on the outer periphery of a tube member, a heating means for the material, and a core material disposed inside the tube member. I do.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is an application of a material which easily expands by heat to a mold. The operation will be described by taking a case of joining tubes of different diameters as an example. First, as shown in FIG. 2, an inner tube 1 and an outer tube 2 having an inner diameter larger than the outer diameter of the inner tube 1 are coaxially overlapped, and a thermal expansion material 4 is provided on the outer periphery of a heater 5 on the outer periphery thereof. Place the processing die. Note that a core material 3 for retaining the inner diameter is inserted inside the inner tube 1.

Subsequently, the thermal expansion material 4 is heated by the heater 5. Then, the portion made of the thermal expansion material 4 thermally expands,
The outer tube 2 is pressed. At this time, it is possible to control the expansion amount of the thermal expansion material 4 by adjusting the heating amount. FIG. 3 shows a state where the inner tube 1 is pressed until the inner wall of the outer tube 2 contacts the inner tube 1. If the tubes of different diameters are made of a thermoplastic resin, heating for expanding the thermally expandable material 4 can be used at the same time as heat welding of the tubes.

In the case where the above-mentioned tubes of different diameters are made of a material that cannot be heat-welded and an adhesive is used, even pressure can be applied from the entire circumference by the same action, and bonding can be performed.

Next, by stopping the heating, the thermal expansion material 4 returns to the volume before the heating, as shown in FIG. 1, and the compression obtained by the thermal expansion can be released.

The above is the outline of the operation of the present invention, and the form of the present method and apparatus will be further supplemented. First, the case where the heater 5 is used as the heat source of the processing die has been described. Or hot air or light rays (laser light, lamp light, far infrared rays, etc.), or heating by electromagnetic induction. In the case of heating by electromagnetic induction, a material that can easily generate heat, for example, stainless steel, iron, chromium, nichrome, lead, nickel, brass, silicon iron, M
In addition to a method of incorporating n-Zn ferrite, a magnetic material, or the like into the thermal expansion material, a method of heating the thermal expansion material itself by kneading the magnetic material into the thermal expansion material is also possible.

Although the processing mold has been described as having a structure in which a thermal expansion material is provided inside a heater, for example, even if a structure in which a heat source is provided inside a thermal expansion material is used, a complete support There may be no structure. However, as a method of effectively utilizing the expansion force of the thermal expansion material, a structure in which a support 7 for restricting expansion to a part other than the intended part as shown in FIG.

As the thermal expansion material, an elastic resin having high thermal expansion and heat resistance can be used. For example, silicone rubber is desirable. Silicone rubber belongs to a class having a large coefficient of thermal expansion among resins, and has a linear expansion coefficient of 0.02 to 0.02.
It is as large as 0.03% / degree and the thermal conductivity is 0.0007 ca
1 / cm-sec-degree, which is about twice that of ordinary organic rubber. In addition, it is excellent in heat resistance and mold release,
In joining thermoplastic resins, it is the best material because the heat for heating the thermal expansion material can be used for thermal processing of the tube.

Furthermore, as a method for improving or imparting thermal expansion properties, a structure having closed cells in the resin can increase the apparent expansion rate. For example, in the case of silicone sponge, the expansion can be increased by a factor of about 4 at heating at 200 degrees Celsius compared to the case without bubbles. Further, even if the material has a small linear expansion coefficient by this method, thermal expansion can be imparted to some materials, and the material can be used as the thermal expansion material of the present invention.

As a method of controlling the amount of pressing of the processing die, a method of controlling the heating temperature of the thermal expansion material, or a method of determining the heating temperature and then reaching the predetermined pressing amount at the heating temperature. It may be performed by any one of the methods of calculating and setting the gap between the pipes to be processed in advance.

Further, as described above, when the pipes of different diameters are each made of a thermoplastic resin, the heating can be simultaneously diverted to the thermal welding of the pipes in order to expand the thermal expansion material. If the temperature at which the pipe is melted is known in advance, the latter method described above, that is, the gap between the processing die and the pipe may be set so that the required compression amount is obtained at that temperature.

After the joining, when removing the processed tube from the processing mold, the heat expansion material is contracted to the initial volume by stopping the heating of the heat expansion material, and a resin having releasability, for example, silicone rubber, is used. If there is, release operation is also realized at the same time.

Further, according to the present invention, since a clearance between the processing die and the pipe can be provided, the insertion and removal of the pipe can be easily performed.

The method of forming the thermal expansion material layer includes coating, coating,
Alternatively, it may be a coating. In short, the function of the present invention is achieved if it is possible to press the pipe to be processed when the material layer which can be easily expanded by heat expands.

Finally, in the description of the operation of the present invention, the case where the pipes are joined by compressing force has been described as an example. It can be applied to thin wall processing and processing of outer diapers (embossing etc.) on the surface. It can be widely applied to processing that requires a pressing force on the surface of a processed member.

The effect of the present invention is that a force can be easily generated from the entire periphery of the processed member toward the central axis, and the pressing force is strong.

Further, the compression amount can be easily controlled by setting the heating temperature of the heat-expandable material or the gap between the processing die and the processing member.

Further, if the processed members are thermoplastic resins, heat welding can be simultaneously performed by heating for expanding the thermally expandable material.

[0027]

EXAMPLE Silicone rubber was used as the material for thermal expansion, and a stainless steel ring with an outer diameter of 10 mm on the outer periphery and an inner diameter of 1.15 mm on a stainless ring.
Incorporate the silicone rubber mold so that it has a hole,
Furthermore, make a processing mold with both ends covered with bakelite,
A polyethylene inner pipe having an inner diameter of 0.70 mm and an outer diameter of 0.90 mm and a polyethylene outer pipe having an inner diameter of 0.92 mm and an outer diameter of 1.10 mm were coaxially overlapped and inserted.

The clearance between the hole of the silicone rubber mold and the outer diameter of the outer tube was set to about 50 microns to ensure operability at the time of insertion. Further, as a heating method, a work coil was arranged around a processing die, and a heating method using an electromagnetic induction welder was employed. Also, a core material was inserted to maintain the inner diameter of the inner tube.

The silicone mold was heated to about 150 degrees Celsius and expanded to a size slightly smaller than the outer diameter of the outer tube. The outer tube and the inner tube are melted by heat transfer from the stainless ring,
Further, they were mutually welded by the pressure of the silicone mold.

After the completion of the joining, the heating was stopped and the temperature was cooled to near normal temperature. The silicone mold gradually shrunk to the initial diameter upon cooling and spontaneously separated from the outer tube. Further, uniform and strong bonding was achieved at the welded portion.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which heating is stopped and a thermal expansion material is contracted.

FIG. 2 is a cross-sectional view showing a state in which an inner tube and an outer tube are overlapped and a processing die is arranged on the outer periphery thereof

FIG. 3 is a cross-sectional view showing a state in which a thermal expansion material is expanded to compress an outer tube.

FIG. 4 is a perspective view showing a structural example of a processing die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner pipe 2 Outer pipe 3 Core material 4 Thermal expansion material 5 Heater 6 Heat source 7 Supporting tool

Claims (7)

[Claims] In a method of processing a tube member by pressing the tube member from the outer periphery, a thermal expansion material is arranged on the outer periphery of the tube member, the material is expanded by heating, and the tube member is processed by the expansion force. A method for processing a pipe, comprising: 2. The processing method according to claim 1, wherein the pipe member is a pipe having a different diameter. 3. The processing method according to claim 1, wherein said pipe member is a pipe made of a thermoplastic resin. 4. The processing method according to claim 1, wherein the pipe member is a pipe of a thermoplastic resin having a different diameter. 5. A thermal expansion material disposed on an outer periphery of a pipe member;
An apparatus for processing a pipe, comprising: a heating means for the material; and a core material disposed inside the pipe member. 6. The processing apparatus according to claim 5, wherein said heating means is capable of adjusting a heating amount. 7. The processing apparatus according to claim 5, further comprising a support for restricting expansion of the thermal expansion material.