JP2003011226A - High frequency fusion-bonding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency fusion-bonding apparatus capable of heating even a molded object being an object to be fusion-bonded comprising a highly heat-resistant thermoplastic resin like polypropylene to a fusion- bondable temperature in a short time and capable of fusion-bonding a tubular object to be fusion-bonded having a smaller inner diameter as compared with a conventional fusion-bonding apparatus. SOLUTION: The high frequency fusion-bonding apparatus for fusion-bonding a tubular or almost tubular object to be fusion-bonded comprising a thermoplastic resin by high frequency induction heating is equipped with a core rod 4 inserted in the object to be fusion-bonded to support the object to be fusion- bonded in an almost vertical direction, a mold 1 split into two parts respectively having curved surfaces for holding the object to be fusion-bonded, high frequency induction heating parts 3a and 3b for heating the mold 1 and cooling parts 2a and 2b for cooling the mold 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency welding device for heating a mold by induction heating to weld an object to be welded made of a thermoplastic resin.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for welding an object to be welded made of a thermoplastic resin, an apparatus for heating the object to be welded by heating with a mold having an electric heater as a heating source is known. However, when welding an object to be welded made of a highly heat-resistant thermoplastic resin such as polypropylene by using a device having an electric heater as a heating source, the temperature of the mold is raised to a temperature at which welding is possible. However, there is a problem in that the welding cycle becomes long because it takes a long time.

When the material to be welded is a tubular material or a substantially tubular material, when one of the two or more materials to be welded is inserted into the other to be welded, as shown in FIG. 4, a heater is used. There is known a device in which a core rod 14 containing therein is inserted into an object to be welded (not shown) for heating and welding. In the figure, reference numeral 11 denotes a die for sandwiching a material to be welded, and the die 11 is composed of a fixed die 11a and a movable die 11b divided into two parts. A cooling unit 12a and a heater 13a are mounted on the rear surface of the fixed mold 11a, and a cooling unit 12b and a heater 13b are mounted on the rear surface of the movable mold 11b.

The mold 11a, the cooling unit 12a and the heater 13a are mounted on a fixed support base 15.
On the other hand, the mold 11b, the cooling unit 12b and the heater 1
3b is attached to a movable support base 16 that is movable in the left-right direction in FIG. 4 by a hydraulic mechanism (not shown), for example. The core rod 14 is also movable in the left-right direction in FIG.

When the object to be welded is welded using the above apparatus, the movable support 16 is moved to the right in FIG. 4 to form a fixed gap between the molds 11a and 11b, and then the core rod. 1
Insert the object to be welded in No. 4. Next, the movable support 16 is moved to the left in FIG. 4 to sandwich the material to be welded by the curved surfaces of the molds 11a and 11b, and then the heater (not shown) of the core rod 14 is energized to The welded material is heated from the inside and welded. At the same time, the heaters 13a and 13b are energized to heat and weld the object to be welded from the outside.

When the welding is completed by heating for a certain period of time, the heating heater for the core rod 14, the heating heaters 13a and 1
The power supply to 3b is stopped, and cooling water is circulated and supplied to the cooling parts 12a and 12b to cool the material to be welded. After cooling, the movable support 16 is moved to the right in FIG.
Take out from 4. A weld deposit can be obtained by such a series of operations.

In the above welding apparatus, it is necessary to use a core rod 14 having a smaller outer diameter as the inner diameter of the tubular or substantially tubular object to be welded becomes smaller. However, since the core rod 14 has a built-in heater, there is a limit to reducing the outer diameter. If the inner diameter of the material to be welded is too small, the core rod 14 cannot contain the heater and Since it cannot be heated, it sometimes caused defective welding.

[0008]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a temperature at which a material to be welded can be welded in a short time even if it is a molded product of a thermoplastic resin having high heat resistance such as polypropylene. An object of the present invention is to provide a high-frequency welding device capable of increasing the temperature up to, and capable of welding a tubular welded object having an inner diameter smaller than that of a conventional welding device.

[0009]

The high frequency welding apparatus of the present invention is a high frequency welding apparatus for welding a tubular or substantially tubular object to be welded made of a thermoplastic resin by high frequency induction heating. A core rod that is inserted inward to support a welding object in a substantially vertical direction, a die having a curved surface that is divided into two parts and sandwiches the welding object in each, a high-frequency induction heating unit that heats the die, and A cooling unit for cooling the mold is provided.

(Operation) The high-frequency welding device of the present invention comprises a core rod which is inserted into the adherend to support the adherent in a substantially vertical direction, and a curved surface which is divided into two parts and sandwiches the adherent in each. A molded article of a thermoplastic resin having a high heat resistance such as polypropylene as a material to be welded, by including a mold having a mold, a high-frequency induction heating unit that heats the mold, and a cooling unit that cools the mold. Even in this case, it is possible to raise the temperature to a temperature at which welding is possible in a short time, and further, it is possible to weld a tubular welded object having an inner diameter smaller than that of a conventional welding apparatus.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of the high-frequency welding device of the present invention. In the figure, 1 indicates a mold, and the mold 1 is
It is composed of a fixed mold 1a and a movable mold 1b divided into two parts. A cooling unit 2a and a high frequency induction heating unit 3a are attached to the back surface of the fixed mold 1a, and a cooling unit 2b and a high frequency induction heating unit 3b are attached to the back surface of the movable mold 1b. Further, the fixed mold 1a and the movable mold 1b have a bay surface 111.
a, 111b are provided respectively, and this bay phase 1
By 11a and 111b, a tubular or substantially tubular object to be welded can be sandwiched and fixed.

Brass, iron, and stainless steel are used as the material of the mold 1, but stainless steel is preferable from the viewpoint of thermal conductivity, and SUS403 is more preferable among the stainless steels. Also, on the surface of the stainless steel mold 1,
In order to prevent adhesion of the deposit, nickel alloy plating and surface treatment with fluororesin may be applied.

The fixed mold 1a, the cooling unit 2a and the high frequency induction heating unit 3a are integrally attached to the fixed support 5. On the other hand, the movable mold 1b, the cooling unit 2b, and the high-frequency induction heating unit 3b are not shown in FIG.
Is integrally attached to a movable support base 6 which is movable in the direction of the arrow.

The core rod 4 is a fixture for supporting the object to be welded in a substantially vertical direction and preventing the inner diameter of the object to be welded from being deformed, and is movable in the left-right direction in FIG. There is. By moving the core rod 4 in the left-right direction and adjusting its position, it becomes possible to sandwich a tubular or substantially tubular object to be welded from a small outer diameter to a large outer diameter in the bay phase.

When the tubular or substantially tubular object to be welded is welded using the high-frequency welding apparatus, first, the movable support base 6 is used.
1 to the right in FIG. 1 to move the fixed die 1a and the movable die 1b.
After a certain gap is provided between and, an object to be welded (not shown) is inserted and fixed to the core rod 4. Next, the movable support 6
1 to the left in FIG. 1 to move the fixed die 1a and the movable die 1
After the object to be welded is sandwiched between the curved surfaces 111a and 111b of b, the high frequency induction heating units 3a and 3b are energized to weld the object to be welded by high frequency induction heating.

When the welding is completed by heating for a certain period of time, the energization of the high frequency induction heating units 3a and 3b is stopped, and the objects to be welded are cooled by the cooling units 2a and 2b. After cooling, the movable support 6 is moved to the right in FIG. 1, and the material to be welded is pulled out from the core rod 4. A weld deposit can be obtained by such a series of operations. As the cooling unit,
There is no particular limitation, and for example, a pipe to which cooling water can be circulated and supplied can be used.

(Example) Using the high-frequency welding apparatus shown in FIG. 1, a welded material composed of polypropylene resin members A, B and C, whose schematic sectional view is shown in FIG. 2, was prepared by the following procedure. . First, inside the member C, the core rod 4 (diameter 2.8 m
m) was inserted and fixed, and then members B and A were sequentially fitted to the outside thereof to obtain a welded object in which members A, B and C were combined (see FIG. 3). Then, as shown in FIG.
After the movable die 1b is moved to the fixed die 1a side and the portion where the members A, B and C of the objects to be welded overlap each other is sandwiched between the curved surfaces 111a and 111b of the die 11, the high frequency induction heating section 3a and 3b was energized and heated. After heating for 30 seconds, the energization was stopped, and cooling water was supplied to the cooling units 2a and 2b to cool them. After cooling, it was extracted from the core rod 4 to obtain a weld deposit. The members A and C of this welded material were grasped and pulled out with both hands, but they could not be pulled out because they were firmly welded by heating for 30 seconds. As a mold,
A stainless steel (SUS403) subjected to nickel alloy plating and surface treatment with a fluororesin was used.

(Comparative Example) Using the heater-type welding apparatus of FIG. 4, as shown in the schematic sectional view of FIG. 2, a welded material made of polypropylene resin members A, B and C was prepared as follows. It was produced by the procedure. First, the core rod 14 is placed inside the member C.
(Diameter 2.8 mm) was inserted and fixed, and then members B and A were sequentially fitted to the outside thereof to obtain a welded object in which members A, B and C were combined in the same manner as in the example. Then
The movable die 11b was moved to the fixed die 11a side to sandwich the welded object on the curved surface, and then the heaters 13a and 13b were energized and heated. After heating for 180 seconds, the energization was stopped, cooling water was supplied to the cooling parts 12a and 12b, and then it was extracted from the core rod 14 to obtain a weld deposit. When the members A and C of this welded material were grasped and pulled out with both hands, the members B and C were not welded, so that the member C could be easily pulled out. The mold 11 used is the same as that used in the embodiment,
The core rod 14 used was one having an outer diameter of 2.8 mm and no heater.

[0019]

The high-frequency welding apparatus of the present invention has the above-mentioned structure, and can weld in a short time even if the object to be welded is a molded product of a thermoplastic resin having high heat resistance such as polypropylene. Further, it is possible to weld a tubular object having an inner diameter smaller than that of a conventional welding device.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a high-frequency welding device of the present invention.

FIG. 2 is a cross-sectional view schematically showing a structure of a material to be welded used in Examples and Comparative Examples.

FIG. 3 is a perspective view schematically showing a state in which a material to be welded is sandwiched between molds.

FIG. 4 is a perspective view showing an outline of a conventional heater-type welding device.

[Explanation of symbols]

1,11 mold 1a, 11a fixed type 1b, 11b movable 2a, 2b Cooling unit 3a, 3b High frequency induction heating section 4,14 core rod 5,15 Fixed base 6,16 movable platform 111a, 111b curved surface

Claims (3)

[Claims] 1. A high-frequency welding apparatus for welding a tubular or substantially tubular object to be welded made of a thermoplastic resin by high-frequency induction heating, the welding apparatus being inserted inside the object to be welded in a substantially vertical direction. A core rod that supports, a mold that is divided into two parts and has a curved surface that sandwiches the welded object in each part,
A high-frequency welding apparatus, comprising: a high-frequency induction heating unit that heats the mold, and a cooling unit that cools the mold. 2. The high frequency welding device according to claim 1, wherein the material of the mold is stainless steel. 3. The high-frequency welding device according to claim 1, wherein the surface of the die is nickel alloy plated or surface-treated with a fluororesin.