JP4096712B2 - Induction heating coil and induction heating apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating device, and more particularly, to a heating coil with reduced loss due to high-frequency current.
[0002]
[Prior art]
Conventionally, the only metal that can be heated by the induction heating apparatus is an iron-based metal having a high magnetic permeability, but in recent years, heating of metals other than iron, such as copper and aluminum, is also desired. In particular, an induction heating cooker in which a heating device is applied to a cooker has recently been increasingly requested to use a copper pan or an aluminum pan in addition to an iron pan.
[0003]
By the way, in order to induction-heat a copper pan or an aluminum pan, since the magnetic permeability is low, a high frequency current of 40 to 100 kHz higher than 20 to 30 kHz suitable for an iron pan must be passed through the heating coil.
[0004]
However, as the frequency increases, the so-called skin effect causes high-frequency current to flow only in the vicinity of the surface of the conductive wire, so that the effective resistance increases remarkably, and the heat generation based on it increases far beyond the practical range. Therefore, as a method of increasing the surface area and effectively reducing the resistance, a method of reducing the diameter of the conductive wire and bundling several to several tens of conductive wires having a diameter of 0.5 mm or less has been performed (for example, patents). Reference 1).
[0005]
However, in this method, when the high-frequency current is about 70 kHz, even if, for example, the diameter of the copper wire is reduced to about 0.1 mm and more conductors are bundled, the effective resistance due to the skin effect can be reduced, the conductor As a result of using a large number of wires, the proximity effect becomes remarkable and the resistance cannot always be reduced sufficiently. The proximity action here refers to a phenomenon in which when current flows through a nearby conductor, it affects each other via a magnetic field and the current distribution is biased, resulting in an effective increase in resistance on the surface of the conductor. . The proximity action increases as the direction of the high-frequency current is aligned between the conductors and as the distance between the conductors decreases.
[0006]
As a method for solving the above-mentioned problem, it is considered that the coil conductor of the heating coil is formed into a multistage assembly structure in which assembly wires bundled with strands are further assembled, and at least one assembly wire is formed by braiding. It is done. The technical idea is that the directions of the assembly lines are not uniform and are not in close contact with each other, whereby the proximity effect can be suppressed and the coil resistance against high frequency current of the heating coil can be reduced.
[0007]
[Patent Document 1]
Japanese Examined Patent Publication No. 63-47238 [0008]
[Problems to be solved by the invention]
However, in the conventional configuration, the coil resistance to the high-frequency current of the heating coil can be reduced. However, the heating coil for heating a low-permeability pan such as a copper pan or an aluminum pan using these configurations. In order to make a coil conductor, it is necessary to make the conductor wire diameter as thin as possible to 0.1 mm or less and to bundle as many strands as possible to form a coil conductor (for example, 1000 to 3000 wires).
[0009]
When the coil conductors are formed by making the conductor diameter of the strands as thin as possible and bundling as many strands as possible, the thickness of the insulator used for insulation between the strands is not practical for coil conductors. In order to secure a practical outer diameter (φ2.0 to φ4.0 mm) while securing an area (2.0 to 5.0 mm ² ), the thinner one is desirable. This practical cross-sectional area and outer diameter are empirical to efficiently radiate the heat of coil conductors and provide induction heating devices for heating low permeability pans such as copper pans and aluminum pans. Numerical values (for example, when the conductor diameter of the strands is 0.05 mm, the thickness of the insulator used for insulation between the strands is 3.5 μm, and the number of strands is 1620, the cross-sectional area of the coil conductor is 3. 18 mm ² , and the coil wire diameter is φ2.75 mm).
[0010]
Also, in order to efficiently dissipate the heat generated by the coil conductor, the material of the element wire used for the coil conductor is preferably a conductor with low conductor resistance and high thermal conductivity / heat dissipation, and copper wire is generally used. It is.
[0011]
However, as the insulator used for insulation between the strands, a material having high heat conductivity and heat dissipation is also desired, but polyimide (PI) resin as a generally used high heat resistant insulator is copper. Compared to the above, the thermal conductivity is 1/1000 or less (copper 403 W / m ° C., polyimide resin 0.22 W / m ° C.). Would be desirable.
[0012]
Further, as the conductor diameter of the wire becomes thinner, it is difficult to make the insulator thicker in terms of manufacturing, and of course, the cost is also increased. However, when the insulator is thinned, the reliability with respect to the insulation between the strands decreases, and there are problems such as scratches and breakage when the coil conductor is wound.
[0013]
In addition, in order to heat a low-permeability pan such as a copper pan or an aluminum pan, a high-frequency current of 40 to 100 kHz higher than 20 to 30 kHz suitable for an iron pan must be passed through the heating coil. However, the higher the frequency, the lower the dielectric strength of the insulator, and there is a problem that the reliability of insulation between the coil conductors of the heating coil wound with the coil conductors is lowered.
[0014]
In addition, as a fixing method of the heating coil formed by winding the coil lead wire, a method of applying heat to the heating coil to soften and fix the insulator is generally used. However, there is a problem that the reliability of insulation is lowered and the fixing strength is not stabilized.
[0015]
The present invention solves the above-described conventional problems, reduces the effect of proximity action, reduces the coil resistance to high-frequency current of the heating coil, ensures the reliability of insulation, and when winding the coil conductor An object of the present invention is to provide an induction heating apparatus that eliminates scratches and breaks and improves the fixing strength of a heating coil formed by winding a coil conductor.
[0016]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, the induction heating coil of the present invention has a two-layer structure in which at least a part of or the entire outer circumference of an assembly wire in which strands are twisted or an upper assembly wire in which an assembly wire is twisted. While configuring the coil conductor with an insulator made of fluororesin,
The fluororesin used for the outer layer of the insulator increases the fixing strength when it is fixed at a temperature at which the crystallinity is 40% or less and heat is applied and is easily softened.
The coil conductor is wound and then heated, insulation is maintained by the inner layer fluororesin, and the adjacent coil conductors are bonded to each other using the outer layer fluororesin as a fixing layer .
[0017]
The fluororesin exhibits the highest properties among resin materials used as an insulator in terms of electrical characteristics, thermal characteristics, chemical resistance, and the like, and can be coated with a thin wall. Therefore, when forming the coil conductor by making the conductor diameter of the strands as thin as possible and bundling a large number of strands, it is optimal as an insulator for the upper assembly line in which the strands or assembly wires used for the coil conductor are twisted together It is.
[0018]
In addition, the fluororesin is a resin that is more flexible than other resins, and can protect the coil conductor from being scratched or broken during winding.
[0019]
Moreover, since it is the resin which shows the lowest dielectric constant (60 Hz = 2.11 MHz = 2.1) among resin materials, and the dielectric constant hardly changes even in a high frequency region from a commercial frequency in particular, In order to heat a pan with low permeability such as an aluminum pan, a heating coil that must pass a high frequency current of 40 to 100 kHz higher than 20 to 30 kHz suitable for an iron pan is used to ensure reliability against insulation. It can be said that it is an optimal material.
[0020]
In addition, the crystallinity of the fluororesin is generally 30 to 50%. The higher the crystallinity, the higher the melting point, the more stable the electrical and thermal characteristics, and the better the chemical resistance. . Further, the higher the degree of crystallinity, the better the surface smoothness and the higher the non-adhesiveness. In addition, in order to improve the mechanical strength, it is generally desirable to have a high degree of crystallinity.
[0021]
However, in the case of stably fixing a heating coil formed by winding a coil lead wire, a method of applying heat to an insulator and fixing it is generally used. In addition to being difficult, the current situation is that it has not been put into practical use because it inhibits the fixing of the heating coil.
[0022]
Therefore, the present invention reduces the crystallinity of the fluororesin to 40% or less and leaves the amorphous part as much as possible, thereby utilizing the intermolecular bonding force in the amorphous part and improving the surface smoothness. Stable fixing of the heating coil formed by winding the coil conductor using a combination of lowering the anchor effect and using a method of fixing at a temperature that tends to soften by applying heat as the melting point decreases (In this context, intermolecular bond force refers to intermolecular interaction and intramolecular interaction of organic substances, and includes electrostatic force, orientation force, induced force, and dispersion. This is the binding energy of force, charge transfer force and exchange repulsive force).
[0023]
Of course, as described above, the use of fluororesin as an insulator ensures reliability of insulation, eliminates damage and breakage when winding the coil conductor, and winds the coil conductor. The fixing strength of the rotating heating coil is improved, and a heating coil suitable for heating a low-permeability pan such as a copper pan or an aluminum pan can be obtained.
[0024]
Also, heat should be applied by using the second-layer insulator as a fixing layer, and adjacent coil conductors are fixed to each other, and the first-layer insulator is not fixed, so the reliability as the insulating layer is maintained. Can do. In addition, since a double-sided insulator is present between the coil conductors, the reliability of the insulator is further improved.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
According to one aspect of the present invention, the set lines by twisting strands, or at least the outer circumference of the part or the whole consisting of full fluororesin having a two-layer structure insulator superset line twisting wire assembly with constituting the coil conductor similar, the fluorine resin used in the outer layer of insulation is made to increase the fixing strength when adhered to the softened easily temperature applying heat crystallinity of 40% or less, Induction heating characterized in that the coil conductor is wound and then heated, and insulation is maintained with the fluororesin of the inner layer, and the adjacent coil conductors are bonded to each other using the fluororesin of the outer layer as a fixing layer. by a coil, when creating a heating coil formed by winding a coil conductor, wider spacing between the coils conductors since the insulator is present between the coils conductors, reduces the effect of turn proximity effect, heating co Coil resistance decreases for Le of the high frequency current.
[0026]
Moreover, the reliability with respect to insulation is improved by the presence of an insulator between coil conductors having a particularly large potential difference. Moreover, the damage | wound and fracture | rupture when winding a coil conducting wire are eliminated with the softness | flexibility of a fluororesin.
[0027]
In addition, by making the crystallinity of the fluororesin 40% or less, the surface smoothness can be lowered, the adhesion can be increased, the fixing strength between the coil conductors can be increased by the anchor effect, and heat can be applied. Thus, the intermolecular bonding force in the non-crystalline part is utilized, and the melting point is lowered to facilitate softening, thereby further improving the fixing strength of the heating coil.
[0028]
In addition, by making the insulator made of fluororesin into a two-layer structure, the coil conductor is wound and heat is applied to the heating coil to soften and fix the insulator, and the second insulator is used as the fixing layer. Heat is applied and adjacent coil conductors are fixed to each other, and the first insulator is not fixed. Therefore, reliability as an insulating layer can be maintained. In addition, since a double-sided insulator is present between the coil conductors, the reliability of the insulator is further improved.
[0029]
According to a second aspect of the present invention, the coil conductor is formed by twisting together the strands or the assembly wires in which the first insulator is formed at least partially or entirely on the outer periphery to form an upper assembly wire, and at least the outer periphery of the coil conductor part or the whole constituted by the second insulating body consisting of two-layer structure fluororesin, the second fluororesin used for the outer layer of insulation, heat crystallinity of 40% or less When the coil wire is wound and heated, the insulation strength is maintained with the fluororesin of the inner layer and the fluororesin of the outer layer is fixed. When the heating coil formed by winding the coil conductor is created by forming an induction heating coil characterized by adhering the coil conductors adjacent to each other as a layer , the first insulation is formed between the strands or between the assembly wires. Body As a result, the spacing between the strands or the assembly wires is widened, and the second insulator is present between the coil conductors, so that the spacing between the coil conductors is also widened. Coil resistance to high frequency current is reduced.
[0030]
Moreover, the reliability with respect to insulation is further improved by the presence of double insulators between the strands or the assembly wires and between the coil conductors. In addition, scratches and breaks when winding the coil conductor are eliminated by the flexibility of the fluororesin, and the first insulator is hard to be damaged by the protective action of the second insulator, and the quality is stabilized and workability is improved. Will also improve. Further, the fixing strength of the heating coil can be improved by setting the crystallinity of the fluororesin to 40% or less.
[0031]
In addition, as a method of fixing the second insulator made of a fluororesin with a two-layer structure, the coil conductor is wound and heat is applied to the heating coil to soften and fix the insulator. Heat is applied as the fixing layer and adjacent coil conductors are fixed to each other, and the first insulator is not fixed, so that the reliability as the insulating layer can be maintained. In addition, since a double-sided insulator is present between the coil conductors, the reliability of the insulator is further improved.
[0032]
The invention according to claim 3 comprises the induction heating coil according to any one of claims 1 to 2 , whereby induction heating with small high-frequency loss, stable shape and quality, and easy manufacture is provided. Since the coil is provided in the apparatus, an object to be heated made of a low resistivity material such as aluminum can be heated, and a cooling structure can be simplified and an inexpensive induction heating apparatus can be provided.
[0033]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0034]
Example 1
FIG. 1 is a cross-sectional view showing a cross-sectional shape of a coil conductor in a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the induction heating cooker of this embodiment. As shown in FIG. 1, the feature of this embodiment is that the strands or the assembly wires 1 are twisted to form the upper assembly wire 2, and at least a part or the whole of the outer periphery of the coil conductor 3 is made of a fluororesin. And a coil conductor 3 having a crystallinity of 40% or less of the insulator 4 made of a fluororesin, and a heating coil 5 formed by winding the coil conductor 3 is provided as shown in FIG. It is characterized by that.
[0035]
The induction heating cooker includes a top plate 7 on which the object to be heated 6 is placed, a high-frequency circuit 8 that supplies a high-frequency current to the heating coil 5, and a main body shell 9. Further, as described above, when a high frequency current of 40 to 100 kHz is passed through the heating coil 5 in order to heat the heated body 6 having a low magnetic permeability such as a copper pan or an aluminum pan, the heating coil 5 has a so-called skin effect. Effective resistance increases. Therefore, in order to reduce the influence of the skin effect, the conductor diameter of the strand or assembly wire 1 is made as thin as possible to 0.1 mm or less, and the coil conductor 3 is formed by bundling as many strands or assembly wires 1 as possible. There is a need to.
[0036]
In consideration of the cross-sectional area or the outer diameter of the practical coil conductor 3 described above, the conductor diameter and the number of the strands or the assembly wires 1 are 0.1 to 0.3 mm. Alternatively, the number of collecting lines 1 is preferably 1000 to 3000. Moreover, it is desirable that the thickness of the insulator 4 made of a fluororesin used to insulate the upper assembly wire 2 formed by twisting the strands or the assembly wire 1 is as thin as possible, but the effective distance between the coil conductors 3 is reduced. The increase in resistance due to the proximity action becomes remarkable.
[0037]
Accordingly, in the present invention, the coil wire 3 is formed by twisting the strands or the assembly wire 1 to form the upper assembly wire 2 and providing the insulator 4 made of fluororesin on at least a part or the whole of the outer periphery of the coil conductor 3. When the heating coil is produced by winding the wire, the insulator 4 made of a fluororesin is present between the coil conductors 3, so that the interval between the coil conductors 3 is widened and an increase in resistance due to the proximity action can be suppressed.
[0038]
As a method of constructing the insulator 4 made of a fluororesin, compression molding, extrusion molding, coating, painting, and the like are conceivable, but a designer can arbitrarily select in view of economy and workability.
[0039]
The grade used as the insulator 4 made of fluororesin includes PTFE, PFA, FEP, ETFE, etc., but the designer considers the heating value of the heating coil 5, the heat dissipation capability, the required insulation performance, etc. Can be arbitrarily selected. The thickness of the insulator 4 made of a fluororesin is preferably in the range of 25 to 300 μm in view of the practical outer diameter of the coil conductor 3.
[0040]
Further, as a method for fixing the heating coil formed by winding the coil conducting wire 3, a method of applying heat to the heating coil to soften and fix the insulator 4 made of fluororesin is generally used. Since the high non-adhesive property of the resin inhibits the fixing of the heating coil, the fixing strength is not stable. Therefore, the present invention uses the intermolecular bonding force in the amorphous part by making the crystallinity of the insulator 4 made of fluororesin 40% or less and leaving the amorphous part as much as possible. Using the anchor effect by lowering the surface smoothness and the method of fixing by fixing the temperature at a temperature that is easy to soften by applying heat by lowering the melting point, the coil conductor 3 is wound in a balanced manner. Thus, a stable fixing strength of the heating coil 5 is obtained.
[0041]
It goes without saying that the crystallinity of the insulator 4 made of a fluororesin is more effective for fixing because a larger amount of amorphous portion remains when the crystallinity is reduced to 35% or less, 30% or less, or 25% or less. However, it is necessary to determine in view of the grade of fluororesin, workability, and the like.
[0042]
Further, as a method for reducing the crystallinity of the insulator 4 made of a fluororesin, as a countermeasure on a material basis, the size of the raw material spherulite is increased. In the case of comparing the crystallinity between the spherulite sizes of 5 μm and 50 μm as an example using PFA, when processed under the same conditions, the crystallinity of 5 μm = 44.2% is 50 μm = 35 .9% crystallinity, and the larger the spherulite size, the lower the crystallinity.
[0043]
In addition, as a response at the processing base when the coil conductor 3 is configured as an insulator, first, the processing step is a process of heating and melting the raw material, covering the coil conductor, cooling and curing, Rapid cooling at the time of this cooling can be mentioned.
[0044]
As a means for cooling, air cooling, water cooling, hot water cooling, oil cooling, etc. can be considered, but water cooling or hot water cooling is desirable from the viewpoint of economy and ease of handling. When the degree of crystallinity is compared between the case where PFA is gradually annealed in the air and the case where it is rapidly cooled in water (when the spherulite size is the same at 5 μm), slow cooling in the air = 44.2. % Crystallinity, quenching with water = 36.9% crystallinity, and quenching with water results in lower crystallinity.
[0045]
Moreover, since the temperature is easily lowered by lowering the temperature at which the raw material is heated and melted, the same effect as that obtained by rapid cooling can be obtained. However, the lower the melting temperature, the better. Naturally, the melting temperature is higher than the melting point of the resin, and it is desirable to determine it in view of processability and the like.
[0046]
Actually, when the fixing strength is compared using FEP as an example, the fixing strength between the coil conductors 3 at a melting temperature of 375 ° C. is 2 to 3 N, whereas the fixing strength between the coil conductors 3 at a melting temperature of 330 ° C. is The fixing strength is improved about 10 to 12N and about 5 times. The value of the fixing strength of 10 to 12 N is almost the same as the tensile strength of the base material, and it can be seen that the fixing strength is stable.
[0047]
In the case of extrusion molding, it is also effective to increase the extrusion speed. Also, as a matter of course, according to the present embodiment, as described above, by using a fluororesin as an insulator, reliability for insulation is ensured, and when the coil conductor is wound, damage and breakage are caused. The heating coil suitable for heating the pan with low magnetic permeability such as a copper pan and an aluminum pan can be obtained by eliminating the problem and improving the fixing strength of the heating coil formed by winding the coil conductor.
[0048]
FIG. 3 is a cross-sectional view showing a cross-sectional shape of another coil conductor in the present embodiment. In the configuration described in this embodiment, the coil conductor 3 is further twisted to form a multi-layered structure. When the heating coil 5 formed by winding the coil conducting wire 3 is created, the interval between the upper assembly wires 2 is further widened, and consequently the influence of the proximity action is reduced, and the coil resistance to the high frequency current of the heating coil is reduced.
[0049]
Further, since the insulator 4 made of a fluororesin is present between the upper assembly line 2 and the coil conductor 3, the reliability of insulation is further improved. Moreover, the damage | wound and fracture | rupture at the time of winding the coil conducting wire 3 are eliminated with the softness | flexibility of the insulator 4 which consists of a fluororesin. Further, the fixing strength of the heating coil can be improved by setting the crystallinity of the insulator 4 made of fluororesin to 40% or less.
[0050]
FIG. 4 is a cross-sectional view showing a cross-sectional shape of another coil conductor in the present embodiment. In the configuration described in this embodiment, the insulator 4 made of fluororesin has a two-layer structure, so that the coil conductor 3 is wound and heat is applied to the heating coil 5 to soften and fix the insulator 4 made of fluorine. As a method for this, heat is applied by using the second-layer insulator 11 as a fixing layer, and the adjacent coil conductors 3 are fixed to each other, and the first-layer insulator 10 is not fixed. Sex can be maintained.
[0051]
Further, since there are double insulators between the coil conductors 3, the reliability of insulation is further improved. In addition, the fluororesin used for the first insulator 10 has a high melting point grade (for example, PFA: 310 ° C.), and the fluororesin used for the second insulator 11 has a lower melting point than the first insulator 10. If the grade (FEP: 275 ° C.) is used, the second layer can be more effectively used as the fixing layer. In addition, by controlling the crystallinity of an insulator made of a fluororesin, the same effect can be obtained even with the same grade.
[0052]
(Example 2)
FIG. 5 is a cross-sectional view showing the cross-sectional shape of the coil conductor in the second embodiment of the present invention. The feature of the present embodiment is that, as shown in FIG. 5, the upper assembly wire 2 is formed by twisting the strands or the assembly wire 1 in which the first insulator 12 is formed at least partially or entirely on the outer periphery, and at least the coil A part or the whole of the outer periphery of the conducting wire 3 is constituted by the second insulator 13 made of fluororesin, and the coil conducting wire 3 is produced in which the crystallinity of the second insulator 13 made of fluororesin is 40% or less. However, as shown in FIG. 2, a heating coil 5 formed by winding the coil conducting wire 3 is provided.
[0053]
Since the first insulator 12 is present between the strands or the assembly wires 1, the spacing between the strands or the assembly wires 1 is widened, and the second insulator 13 made of a fluororesin is present between the coil conductors 3. The spacing between the conductive wires 3 is also widened, so that the influence of the proximity action is reduced, and the coil resistance to the high frequency current of the heating coil is reduced.
[0054]
Further, since there are double insulators between the strands or the assembly wires 1 and between the coil conductors 3, the reliability with respect to insulation is further improved. Further, the first insulator 13 is made of the second insulator 13 made of fluororesin so as to eliminate damage and breakage when the coil conductor 3 is wound, and to protect the first insulator 13 by the protective action of the second insulator 13 made of fluororesin. The insulator 12 is not easily damaged and the quality is stabilized, and at the same time the workability is improved.
[0055]
Further, the fixing strength of the heating coil is improved by setting the crystallinity of the second insulator 13 made of fluororesin to 40% or less. The insulator used for the first insulator 12 is desirably as thin as possible in order to realize a practical outer diameter of the coil conductor 3.
[0056]
For example, the range of 0.5 to 30 μm is desirable. In terms of material, since the strands or the assembly wires 1 have the same potential between the strands, they are cheaper than fluororesins and are commonly used thermoplastic resins such as polyimide resins and polyamides. A resin, a polyetherimide resin, a polyesterimide resin, a polyurethane resin or the like coated and baked is desirable. Other examples, effects, operations, and the like are the same as those described in the first embodiment.
[0057]
FIG. 6 is a cross-sectional view showing the cross-sectional shape of another coil conductor in the present embodiment. In the configuration described in this embodiment, when the heating coil 5 formed by winding the coil conductor 3 is created by further twisting the coil conductor 3 to form a multi-stage lap twist structure, the interval between the upper assembly lines 2 Is spread, and the influence of the proximity effect is reduced, and the coil resistance of the heating coil with respect to the five high-frequency currents is reduced.
[0058]
Further, the presence of triple insulators between the strands or assembly wires 1 and between the upper assembly wires 2 and between the coil conductors 3 further improves the reliability of insulation. Moreover, the damage | wound and fracture | rupture when winding the coil conducting wire 3 are eliminated with the softness | flexibility of a fluororesin. Further, the fixing strength of the heating coil 5 can be improved by setting the crystallinity of the fluororesin to 40% or less.
[0059]
FIG. 7 is a cross-sectional view showing a cross-sectional shape of another coil conductor in the present embodiment. In the structure described in the present embodiment, the second insulator 13 made of a fluororesin has a two-layer structure, whereby the coil conductor 3 is wound and heat is applied to the heating coil to soften and fix the insulator. Then, heat is applied by using the second-layer insulator 11 as a fixing layer and adjacent coil conductors are fixed to each other, and the first-layer insulator 10 is not fixed, so that the reliability as the insulating layer is maintained. can do. Further, since a double insulator on one side exists between the coil conductors 3, the reliability of the insulator is further improved.
[0060]
The effects of Examples 1 and 2 are particularly effective when the object to be heated is induction-heated with a high frequency current of 40 to 100 kHz such as a copper pan or an aluminum pan.
[0061]
In addition, although the present Example demonstrated the induction heating cooking appliance as an example of an induction heating apparatus, the same effect is acquired also in other various induction heating apparatuses.
[0062]
【The invention's effect】
As described above, according to the invention described in claim 1 to 3, it is possible to reduce the influence of the skin effect and proximity effect, to obtain a heating coil with a reduced coil resistance against high-frequency current.
[0063]
It also ensures reliability of insulation, eliminates scratches and breaks when winding coil conductors, improves the fixing strength of heating coils that are wound around coil conductors, and has permeability such as copper pans and aluminum pans It is possible to heat a heating coil suitable for heating a low-pot pan, or an object to be heated made of a material having a low resistivity such as aluminum, and a cooling structure can be simplified and an inexpensive induction heating apparatus can be obtained.
[0064]
Furthermore, heat is applied by using the second-layer insulator as a fixing layer, and the adjacent coil conductors are fixed to each other, and the first-layer insulator is not fixed, so that the reliability as the insulating layer is maintained. Can do. Further, since the one side double insulation between the coils conductors are present, it is to further improve the reliability against the insulator.
[Brief description of the drawings]
1 is a cross-sectional view of a coil conductor used in the induction heating cooker in Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the configuration of the induction heating cooker. FIG. 3 is another coil conductor used in the induction heating cooker. FIG. 4 is a cross-sectional view of another example of a coil conductor used in the induction heating cooker. FIG. 5 is a cross-sectional view of a coil conductor used in the induction heating cooker according to Embodiment 2 of the present invention. ] Cross-sectional view of another example of coil lead used in the induction heating cooker [FIG. 7] Cross-sectional view of another example of coil lead used in the induction heating cooker
DESCRIPTION OF SYMBOLS 1 Elementary wire or assembly line 2 Upper assembly line 3 Coil conductor 4 Insulator made of fluororesin 5 Heating coil 6 Heated body 7 Top plate 8 High-frequency circuit 9 Main body outline 10 First layer insulator 11 Second layer insulator 12 1st insulator 13 2nd insulator which consists of fluororesin

Claims (3)

The coil conductor is composed of an insulator made of a fluororesin having a two-layer structure, at least a part of or the entire outer circumference of the assembly wire in which the strands are twisted together, or the upper assembly wire in which the assembly wires are twisted,
The fluorine resin used in the outer layer of insulation is made to increase the fixing strength when adhered to a degree of crystallinity given softening easy temperature heat and 40% or less,
The coil wire is heated after winding, induced and characterized in that bonding the said coil conductors fluororesin adjacent the pinned layer of the inner layer fluororesin maintaining insulating said outer layer of another heating coil. The coil conductor is formed by twisting together strands or assembly wires in which the first insulator is formed on at least a part or the whole of the outer periphery to form a higher assembly wire, and at least a part or the whole of the outer periphery of the coil conductor is a two-layer structure. A second insulator made of fluororesin,
The fluororesin used for the outer layer of the second insulator, it enhances the fixing strength when adhered to a degree of crystallinity given softening easy temperature heat and 40% or less,
The coil wire is heated after winding, induced and characterized in that bonding the said coil conductors fluororesin adjacent the pinned layer of the inner layer fluororesin maintaining insulating said outer layer of another heating coil. Induction heating apparatus comprising an induction heating coil of claim 1 or 2.

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