JPS633434B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency induction heating coil device, and more particularly to a high frequency induction heating coil device including a coil made of an annular pipe through which cooling water flows.

When a thermoplastic resin tape is thermally bonded to the outer circumferential surface of the open end of a metal can leaving an outwardly protruding portion, and then the protruding portion is thermally bonded to the end surface and inner circumferential surface of the open end, for example, As proposed in Japanese Patent Application No. 57-42521, when the tape portions on the outer circumferential surface and the inner circumferential surface are pressed by the die and the core, respectively, the ring-shaped high frequency induction built in the die is Preferably, the second thermal bonding is performed by induction heating the opening end using a heating coil device.

In this case, in order to prevent the heating coil from overheating, it is desirable to use a water-cooled pipe through which cooling water flows, but the width (height in the axial direction) of the opening end, which is the heated part, is usually 5 to 6 mm. Therefore, when using a water-cooled pipe with multiple turns, the diameter of the pipe must be made small, which tends to cause clogging, so it is more desirable to use a water-cooled pipe with one turn.

However, it has been found that the following problem occurs when using a high-frequency induction heating coil device 2 equipped with a coil 1 made of a conventional one-turn water-cooled pipe as shown in FIG. 1, for example.

That is, the heating coil device 2 includes a coil 1 formed from one copper pipe and a pair of power supply bodies 3.
a, 3b, and the power feeders 3a, 3b are connected to both ends 1a, 1b of the coil 1, with a gap 5 between both ends 1a, 1b, and a gap 6 between the power feeders 3a, 3b near the coil 1. is provided with an electrical insulator layer 4 (made of, for example, heat-resistant synthetic resin). Then, induction heating is performed as uniformly as possible along the circumferential direction of the open end 7 to prevent deterioration of the thermoplastic resin tape parts 8 and 9 due to overheating, or to form an incomplete thermal bond on the inner tape part 9. In order to prevent this, the gaps 5 and 6 are set as narrow as possible, for example, about 0.1 to 0.2 mm.

However, even if the gaps 5 and 6 are narrowed as described above, the temperature rise due to induction heating in the portion 7a of the open end 7 facing the power feeders 3a and 3b is smaller than that in the other portion 7b, and therefore the portion At 7a, the tape portion 9 tends to be unbonded or incompletely bonded, and when the output is increased in an attempt to completely bond it, the other portion 7b will overheat and the tape portions 8 and 9 in contact with the portion 7b will deteriorate. The problem arises that it is easy to use.

A similar problem occurs when the induction heating coil device 2 of the type shown in FIG. 1 is used to heat seal the flange portion of the container body and the lid portion. Furthermore, when a coil with two or more turns is used, a similar problem of non-uniform heating in the circumferential direction is likely to occur (although the degree of non-uniform heating becomes smaller as the number of turns increases).

It is an object of the present invention to solve the problems of the prior art described above.

In order to achieve the above object, the present invention includes a coil having an annular pipe through which cooling water flows, and a coil connected near both ends of the coil that are close to each other. A pair of water pipes made of an electrically insulating material for supplying and discharging the cooling water, and a pair of water pipes for supplying power to the coil, the coil having a relatively thin thickness in the circumferential direction and mutually The present invention provides a high frequency induction heating coil device characterized by having a pair of adjacent power feeders.

The present invention will be described below with reference to the drawings which are examples. In Figures 2 and 3, the first
Parts with the same reference numerals as those in the figures indicate similar parts.

The high-frequency induction heating coil device 12 includes a circular coil 11 made of a copper pipe (with a diameter of, for example, 5 to 6 mm) through which the cooling water 10 can pass, a pair of power supply bodies made of a thin normal copper plate, and a water pipe 18a made of an electrically insulating material for supplying the cooling water 10 to the coil 11, and the cooling water 10.
A drain pipe 18b made of an electrically insulating material is provided for sending out the water.

Both ends 11a and 11b of the coil 11 are close to each other, and their end faces 11a ₁ and 11b ₁ are
They are extensions of power supply bodies 13a and 13b, respectively. The gap 15 between the end surfaces 11a ₁ and 11b ₁ and the gap 16 between the power feeders 13a and 13b are set as narrow as possible, for example, 0.1 to 0.2 mm, and the gaps 15 and 16 are set to the electrical insulating layer 17.
(for example, made of heat-resistant resin such as phenolic resin or polyimide). Gap 15,1
6 is made as narrow as possible so that a locally small portion of the induced current, that is, a locally low heating temperature portion, occurs along the heated portion (in this case, the open end 7). This is to prevent this as much as possible.

The power feeders 13a and 13b also have at least the coil 1.
1, it is preferable that the thickness of the coil 11 in the circumferential direction is thinner in order to uniformly heat the heated part.
If it is too thin, the resistance loss will increase, so it is usually preferable that the thickness is about 1 to 2 mm.

At least the portions of the water pipe 18a and the drain pipe 18b near the coil 11 are made of an electrically insulating material (such as plastic or ceramic) and are bonded to the coil 11 with an adhesive 14. When the coil 11 is made of a good conductor, as in the case of the conventional coil device shown in FIG. The heating temperature of the portion 7a of the corresponding open end 7 becomes considerably lower than that of the other portion 7b, and the tape portion 9 in contact with the inner surface of the portion 7a becomes unheated. Or the tape portion 8 is incompletely thermally bonded or is in contact with another portion 7b.
This is because the components 9 and 9 are overheated and easily deteriorate.

End portion 11a, 1 of coil 11 by cooling water 10
1b, the water pipe 18a and the drain pipe 18b are connected to the end portion 11a, respectively.
and 11b, but within the scope of achieving the purpose of the present invention, the end 1
1a and 11b (in this specification, it is also referred to as being connected near the end in this case).

In order to increase the degree of electromagnetic coupling between the coil 11 and the heated part, that is, the open end 7, a high magnetic permeability material 19 is applied along the entire length of the coil 11, as shown in FIG.
(for example made of ferrite) is preferably provided. In the case of Fig. 2, the ring-shaped high permeability material 1
9 are disposed along the lower surface of the coil 11, and high magnetic permeability material pieces 19a are also disposed on the upper surface near the ends 11a and 11b of the coil. This is the gap 15 and the power supply body 13a,
Coil 11 in the part based on 13b
This is to compensate for a slight decrease in the degree of electromagnetic coupling between the opening end 7 and the opening end 7, and to ensure uniform heating along the circumferential direction of the opening end 7.

4 and 5 show a high-frequency induction heating coil device 22 equipped with a two-turn coil 21 (having an upper coil 21x and a lower coil 21y), and shows a water pipe 28a made of an electrically insulating material.
and drain pipe 28b, and cooling water relay pipe 29
a, 29b are both ends 21a, 21 of the coil 21
b and near the joint between the upper coil 21x and the lower coil 21y. The upper coil 21x and the lower coil 21y are connected to a thin copper plate 30 near both ends 21a and 21b of the coil 21.
(preferably 1 to 2 mm thick).

23a and 23b are power supply bodies, and the coil 21
It is formed by crushing the portion near the coil 21 of a pipe (which is the material of the coil 21) extending outward from both ends 21a and 21b (so that the axial direction of the coil 21 is vertically elongated). coil 21
The power supply bodies 23a and 23b are integrally formed.
In this case as well, since the thickness of the coil 21 of the power feeder in the circumferential direction is thin (preferably about 1 to 2 mm), induction heating is more uniform along the circumferential direction compared to the conventional two-turn coil. can be secured.

The present invention is not limited to the above-described embodiments; for example, the planar shape of the coil may be any shape, such as an ellipse or a square, depending on the shape of the heated portion. Further, the cross-sectional shape of the coil can also take any shape depending on the purpose of use. Furthermore, it goes without saying that the present invention can also be applied to heating members other than the open end of a metal can.

Also, in the case of a one-turn coil, the power supply body may be formed by crushing the pipe that is the coil material (to make it watertight), as in the case of FIG. 4. Moreover, the power feeders 13a and 13b may stand up perpendicularly to the surface of the coil 11.

In the high frequency induction heating coil device of the present invention, both ends of the coil are close to each other, the thickness of the coil in the circumferential direction is relatively thin, and power is supplied from a pair of power feeders that are close to each other, In addition, since the water supply pipe and drain pipe connected near both ends of the coil are made of electrically insulating material, the magnetic flux density generated near both ends of the coil is only slightly reduced compared to that occurring around other parts of the coil. Therefore, it is possible to substantially uniformly inductively heat the heated portion facing the coil along the entire circumference.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of a conventional coil device, FIG. 2 is a front view of a coil device according to a first embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line - in FIG. 2. 4 is a perspective view of a coil device according to a second embodiment of the present invention, and FIG. 5 is a front view taken from the - line in FIG. 4. 10... Cooling water, 11, 12... Coil, 11
a, 11b; 21a, 21b... end, 12, 2
2...High frequency induction heating coil device, 13a, 13
b; 23a, 23b...power supply body, 18a, 28a
... Water pipe, 18b, 28b ... Drain pipe.

Claims (1)

[Claims] 1. A coil having an annular pipe through which cooling water flows, a pair of water pipes made of an electrically insulating material connected near both ends of the coil for supplying and sending out the cooling water; and a high-frequency induction heating coil device, characterized in that the coil has a relatively thin thickness in the circumferential direction and includes a pair of power feeders close to each other for supplying power to the coil.