JPH11102781A - High-frequency forced cooling composite conductor and electromagnetic induction heating coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency forced cooling composite conductor and an electromagnetic induction heating coil which is capable of improving a loss in the electromagnetic induction heating coil, even in a higher-frequency region. SOLUTION: The required number of strands 2 having their required sectional dimensions smaller than a current permeation depth defined by a frequency are insulated from each other, the strands are stranded to each other to form a composite conductor 3, this composite conductor 3 is wrapped in a covered tube 5 consisting of an insulation material, and a passage of a cooling medium for forcibly cooling the composite conductor 3 is formed inside the composite conductor 3 or between the composite conductor 3 and the covered tube 5 for constituting a high-frequency forced cooling composite conductor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high frequency forced cooling composite conductor and an electromagnetic induction heating coil used in a high frequency electromagnetic induction heating apparatus.

[0002]

2. Description of the Related Art Conventionally, various measures have been taken to improve losses such as copper loss in an electromagnetic induction heating coil. Since the electromagnetic induction heating coil is used at a high temperature, it is necessary to cool the coil to protect the conductor itself and the insulator, and therefore, as shown in FIGS.
Is often used. FIG. 3 (a) shows a single-layer coil wound in a cylindrical shape, and FIG. 6 (b)
Denotes a coil wound in multiple layers, 11a denotes an electrical insulating material on the outer surface of the conductor 11, and 13 denotes a heat insulating cylinder for winding the coil.

By the way, when a multi-layered coil is used as compared with a single-layered coil shown in FIG. 6 (a), the number of turns increases and the electric efficiency increases. For this reason, the coil is often wound in multiple layers, but in a multilayer wound coil, an induced current flows through the conductor of the coil wound on the inner layer side due to the coil wound on the outside, and copper loss increases, and the multilayer wound coil increases the copper loss. Will no longer be effective. Thus, as disclosed in Japanese Patent Publication No. 58-14037, for example, as shown in FIG.
The thickness of the conductor 11 of the inner layer side coil 15 is made thinner than that of the inner layer side coil 15.

[0004] Japanese Patent Application Laid-Open No. 6-36869 discloses that
As shown in FIG. 7, a plurality of conductors 18 are brought into contact with the outer periphery of a cooling pipe 17 through which a cooling medium passes, and are helically wound so as to make at least one round between both ends of the conductors. Has been proposed. In FIG.
Reference numeral 18a is an electrical insulating material, and 19 is an attaching material having electrical insulating properties and thermal conductivity for fixing the conductor 18 to the cooling pipe 17.

[0005]

FIG. 6 (b)
In the multilayer wound coil shown in (1), it is known that the conductor 11 of the coil 15 wound on the inner layer side must use a conductor whose thickness is considerably smaller than the penetration depth of the current due to the skin effect determined by the frequency. In the case where the cooling water passage 12 is formed in the conductor 11, there is a limit in making the conductor thinner, and there is a problem that the conductor 11 can be applied to a commercial frequency region having a large current penetration depth but cannot be applied to a high frequency.

In the coil using the composite conductor 16 shown in FIG. 7, since the conductor 18 is indirectly cooled through the wall of the cooling pipe 17, the cooling effect is not sufficient, and the current carrying capacity is suppressed. Therefore, a larger number of conductors 18 are required to flow a required current value, and as a result, a multilayer winding is required to flow a predetermined current value, which is complicated and expensive. Further, when the multilayer winding is performed, the cooling pipe 17 of the composite conductor 16 of the coil wound inside is induction-heated by the coil wound on the outer layer side, which causes a loss.

[0007] Therefore, even in the multilayer wound coil using the composite conductor 16, the limit of the applicable frequency is as low as about 1 to 2 KHz, and there is a problem that it cannot be applied to a higher frequency.

As described above, since it is difficult to apply any of the above to higher frequencies, in the high frequency region, FIG.
As shown in (a), a single-layer wound coil using a conductor 11 having a cooling water passage 12 formed therein is used, and at present, loss improvement at a higher frequency has not been realized.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a high-frequency forced cooling composite conductor and an electromagnetic induction heating coil capable of realizing a reduction in loss of the electromagnetic induction heating coil even in a higher frequency range. .

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, a forced cooling composite conductor for high frequency wave according to the present invention is provided with a reference numeral in the drawing. A required number of strands 2 having a cross-sectional dimension smaller than the determined current penetration depth are insulated from each other, and the strands are twisted together to form a composite conductor 3. The composite conductor 3 is covered with a cladding tube 5 made of an insulating material. A configuration is adopted in which a cooling medium passage 6 for enclosing and forcibly cooling the composite conductor 3 is formed inside the composite conductor or between the composite conductor 3 and the cladding tube 5.

According to a second aspect of the present invention, a cooling medium passage 6 is formed by disposing a plurality of spacers 4 at substantially equal intervals between the composite conductor 3 and the cladding tube 5 enclosing the composite conductor 3. Is adopted.

According to a third aspect of the present invention, a configuration is adopted using the high frequency forced cooling composite conductor 1 according to any one of the first and second aspects.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electromagnetic induction heating coil using a high-frequency forced cooling composite conductor according to one embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a forced cooling composite conductor 1 for high frequency. Reference numeral 2 denotes a strand having a required cross-sectional dimension smaller than the current penetration depth determined by the frequency, and its outer surface is insulated by a water-resistant electric insulating material 2a such as enamel. The composite conductor 3 is constituted by twisting the required number of wires 2 to perform a required transposition and assembling.

As shown in FIG. 2, the composite conductor 3 is made of an insulating material such as Teflon through three or more spacers 4 disposed on the outer surface thereof at substantially equal intervals in the circumferential direction and substantially parallel to the axial direction. A cooling medium passage 6 which is housed in a cladding tube 5 made of a material having high heat resistance and heat resistance and forcibly cools the composite conductor 3 over substantially the entire circumference thereof is formed between the cladding tube 5 and the composite conductor 3. Have been. The spacer 4 is made of a linear material having a circular cross section made of a material having high insulation and heat resistance, such as Teflon, like the cladding tube 5.

Thus, the high-frequency forced cooling composite conductor 1 energizes the composite conductor 3 and forcibly removes heat generated in the composite conductor 3 through the cooling medium passage 6 through the refrigerant. Not equipped with an energizing terminal and a coolant passage.

High frequency forced cooling composite conductor 1 having the above configuration
In this case, the individual wires 2 in the composite conductor 3 have the same level of electrical operation characteristics, so that the level of insulation between the wires 2 may be a low level formed of a thin film, and the layer of the electrical insulating material 2a Since the thickness is small, the cooling characteristics are high, and as a result, a high current-carrying ability can be provided.

The electromagnetic induction heating coil 7 using the above-described forced cooling composite conductor 1 for high frequency is provided with the forced cooling composite conductor 1 for high frequency on the outer periphery of a heat insulating cylindrical body 8 through which an object to be heated is passed.
It is configured by winding a single layer as shown in FIG. 5A or a multilayer winding as shown in FIG.

According to the above-described embodiment, since the composite conductor 3 has a simple structure including the composite conductor 3 in which the strands 2 are assembled, the spacer 4 and the cladding tube 5 and is directly cooled and has a good cooling characteristic, it is small and inexpensive. As a result, a high-frequency forced cooling composite conductor 1 having a high current-carrying capacity can be obtained. Further, for this reason, the loss can be improved even if the electromagnetic induction heating coil 7 does not have a multi-layer winding or a single-layer winding. In addition, since it is constituted by the sufficiently thin strand 2, it is hardly affected by the current penetration depth, and even if it is a multilayer winding, it is hardly affected by the induction heating by the coil wound on the outer layer side. The electromagnetic induction heating coil 7 can also perform multilayer winding, and the loss of the electromagnetic induction heating coil 7 can be further improved by multilayer winding from a low frequency to a high frequency.

Further, the high-frequency forced cooling composite conductor 1 having high flexibility and good workability can be obtained because it is composed of the sufficiently thin strands 2 and the insulating coating tube 5. Therefore, it can be used not only as a conductor of an electromagnetic induction heating coil but also as a lead wire of a high-frequency circuit requiring flexibility.

The effect is shown in a specific example.
30mm at z^TwoConventional single layer using a single conductor of cross-sectional area
In a wound electromagnetic induction coil, the current at 5 KHz
A thickness of about 1 mm was selected based on the penetration depth of
Therefore, the required number of conductors with a thickness of 1 mm and a width of 30 mm
However, in this embodiment, the distance is 30 mm. ^Two
Composite conductor with a diameter of about 7mm to secure the conductor cross-sectional area
3 is sufficient, and the tube 5 for accommodating it is as large as 13 mm in diameter.
The size is fine. Therefore, the conventional width of one winding is 30 mm.
High-frequency forced cooling composite conductor 1 of the present embodiment in the space
Can be wound 2.3 times. That is, the coil loss
It can be seen that can be reduced by half compared with the conventional case.

In the above embodiment, the composite conductor 3 is formed by twisting and gathering the strands 2, and the composite conductor 3
An example is shown in which a spacer 4 made of a wire is interposed between a cladding tube 5 enclosing the same and a cooling medium passage 6 formed between the composite conductor 3 and the cladding tube 5. For example, FIG. As shown, when the composite wires 3 are formed by twisting the strands 2 to form a composite conductor 3, a gap 9 is formed in the projecting portion of the composite conductor 3 so that a part of the composite conductor 3 partially protrudes to the outer peripheral side. And the gap 9 may be used as the cooling medium passage 6. Alternatively, as shown in FIG. 4, when the strands 2 are twisted and assembled to form the composite conductor 3, a gap is formed at the center of the composite conductor 3. 10 may be formed, and the gap 10 may be used as the cooling medium passage 6. Further, other means may be applied. In short, a required number of strands 2 are twisted to form a composite conductor 3, and when the composite conductor 3 is accommodated in the cladding tube 5, the inside of the composite conductor 3 or The cooling medium passage 6 communicating in the longitudinal direction may be formed on the outer peripheral side or on one or both sides between the composite conductor 3 and the cladding tube 5.

[0023]

According to the first aspect of the present invention, a composite conductor is formed by insulating a required number of wires having a cross-sectional dimension smaller than the current penetration depth determined by the frequency from each other and twisting the wires together. Since the composite conductor is covered with a cladding tube made of an insulating material, and a passage of a cooling medium for forcibly cooling the composite conductor is formed inside the composite conductor or between the composite conductor and the cladding tube, a simple structure is provided. Although having a structure, the composite conductor is directly cooled by the cooling medium, so that the cooling characteristics are good, and therefore, a compact, inexpensive, high-frequency forced cooling composite conductor having high current-carrying ability can be obtained. In addition, since it is composed of sufficiently thin strands, it is hard to be affected by the current penetration depth, and even if it is multilayered, it is hard to be affected by induction heating by the coil wound on the outer layer side, so high-frequency electromagnetic Multilayer winding is also possible with the induction heating coil, and the loss of the electromagnetic induction heating coil by the multilayer winding can be further improved from a low frequency to a high frequency. In addition, since it is rich in flexibility, it can be used as a lead wire of a high-frequency circuit requiring flexibility.

According to the second aspect of the present invention, a plurality of spacers are disposed at substantially equal intervals between the composite conductor and the cladding tube enclosing the composite conductor to form the cooling medium passage. , A cooling medium passage can be formed.

According to the third aspect of the present invention, since the electromagnetic induction heating coil is formed by using the high frequency forced cooling composite conductor, the loss can be reliably improved even in the high frequency region as described above. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a high-frequency forced cooling composite conductor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view in a direction perpendicular to an axis of the embodiment.

FIG. 3 is a sectional view similar to that of the other embodiment.

FIG. 4 is a sectional view similar to the above in still another embodiment.

5A and 5B show an electromagnetic induction heating coil using the high-frequency forced cooling composite conductor of the embodiment, wherein FIG. 5A is a longitudinal sectional view of a single-layer wound coil, and FIG. It is.

6A and 6B show a conventional electromagnetic induction heating coil, in which FIG. 6A is a longitudinal sectional view of a single-layer wound coil, and FIG. 6B is a longitudinal sectional view of a multi-layered coil.

FIG. 7 shows another conventional forced cooling composite conductor, wherein (a)
Is a perspective view, and (b) is a cross-sectional view in a direction perpendicular to the axis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High frequency forced cooling composite conductor 2 Element wire 2a Electrical insulating material 3 Composite conductor 4 Spacer 5 Cladding tube 6 Cooling medium passage 7 Electromagnetic induction heating coil

Claims (3)

[Claims] 1. A composite conductor is formed by insulating a required number of wires having a cross-sectional dimension smaller than a current penetration depth determined by a frequency from each other and twisting the wires together to form a composite conductor. A forced cooling composite conductor for high frequency waves, characterized in that a cooling medium passage encased in a tube and forcibly cooling the composite conductor is formed inside the composite conductor or between the composite conductor and the cladding tube. 2. The high-frequency device according to claim 1, wherein a plurality of spacers are arranged at substantially equal intervals between the composite conductor and the cladding tube enclosing the composite conductor to form a cooling medium passage. Forced cooling composite conductor. 3. An electromagnetic induction heating coil comprising the high-frequency forced cooling composite conductor according to claim 1.