WO2017038074A1

WO2017038074A1 - Heating coil and rice-cooker equipped with same

Info

Publication number: WO2017038074A1
Application number: PCT/JP2016/003923
Authority: WO
Inventors: 大矢　弘; 清芽中西; 恵椿; 仁志岩井
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2015-09-02
Filing date: 2016-08-29
Publication date: 2017-03-09
Also published as: JPWO2017038074A1; CN107535022B; JP6832488B2; CN107535022A

Abstract

This heating coil comprises a wound wire (2). The wound wire (2) has a first core wire (3) and a second core wire (6). The first core wire (3) contains a long and narrow first conductor, and a first insulation layer provided on the surface of the first conductor. The second core wire (6) contains a long and narrow second conductor, a second insulation layer provided on the surface of the second conductor, and a fusion layer provided on the surface of the second insulation layer. The present embodiment can prevent the wound wire (2) from being broken in the heating coil production process. The heating coil according to the present embodiment allows a highly reliable rice-cooker to be provided.

Description

Heating coil and rice cooker equipped with the same

The present disclosure relates to a heating coil used in an induction heating cooker and a rice cooker including the heating coil.

Conventionally, in the field of induction heating cookers, in order to reduce the weight of the heating coil and the loss in the heating coil, a wire having a fusion layer on an insulating layer provided on the surface of a conductor such as a copper wire is used. A heating coil used has been proposed (see, for example, Patent Document 1).

FIG. 6A is a cross-sectional view of a strand of a conventional heating coil 200 described in Patent Document 1. FIG. 6B is a cross-sectional view of the heating coil 200.

As shown in FIG. 6A and FIG. 6B, the heating coil 200 is composed of a wire 201. The strand 201 includes a long and thin conductor 202, an insulating layer 203, and a fusion layer 204. The long and thin conductor 202 is composed of a copper wire or the like. The insulating layer 203 is provided on the surface of the conductor 202. The fusion layer 204 is provided on the surface of the insulating layer 203.

As shown in FIG. 6B, a plurality of strands 201 are twisted to form a collective wire 205. When the assembly wire 205 is wound in a spiral shape and then the assembly wire 205 is fused by the fusion layer 204, a disk-shaped heating coil 200 is formed.

In the field of high frequency electric wires, electric wires for suppressing AC resistance, heat generation and power consumption have been proposed. This electric wire has an elongated central conductor, a coating layer provided on the surface of the central conductor, and an insulating layer provided on the surface of the coating layer. The coating layer is formed of a metal different from the metal constituting the central conductor (see, for example, Patent Document 2).

FIG. 7 is a cross-sectional view of a conventional high-frequency electric wire 300 described in Patent Document 2. As shown in FIG. 7, the high-frequency electric wire 300 includes a central conductor 301, a covering layer 303, and an intermetallic compound layer 302.

The center conductor 301 is made of aluminum or an aluminum alloy. The covering layer 303 is made of copper and is provided on the surface of the central conductor 301. The intermetallic compound layer 302 is formed between the central conductor 301 and the covering layer 303 so that the composition gradually changes from the central conductor 301 to the covering layer 303. The intermetallic compound layer 302 has a larger volume resistivity than the coating layer 303.

The present inventors examined the adoption of the above-described conventional high-frequency electric wire as the conductor of the wire constituting the above-described conventional heating coil in order to suppress the heat generation and power consumption of the heating coil.

JP 59-086188 Japanese Patent No. 5266340

However, simply combining the above-described conventional high-frequency electric wire with the wire constituting the above-described conventional heating coil is not sufficient from the viewpoint of the reliability of the heating coil.

For example, when the conventional heating coil described in Patent Document 1 is combined with the conventional high-frequency electric wire described in Patent Document 2, the wires constituting the assembly line of the heating coil are fused with the center conductor, the covering layer, the insulating layer, and the like. Including layers. The central conductor is made of aluminum or an aluminum alloy. The coating layer is made of copper and is provided on the surface of the central conductor. The insulating layer is provided on the surface of the coating layer. The fusion layer is provided on the surface of the insulating layer.

The heating coil is formed by twisting a plurality of the above-described strands and fusing the spirally assembled wires. In this configuration, since the covering layer of the strand is composed of a metal different from the metal constituting the central conductor of the strand, the properties such as the spreadability are different between the central conductor of the strand and the covering layer of the strand. . In general, since aluminum is inferior to copper in terms of spreadability, the central conductor of the strand is inferior to the coating layer of the strand in terms of spreadability.

On the other hand, if all the strands constituting the assembly line have a fusion layer, the assembly line becomes too hard. For this reason, in the collective wire, the heating coil may be disconnected in the manufacturing process.

The present disclosure solves the above-mentioned conventional problems, and forms a heating coil that is not disconnected in the manufacturing process even if the conductor contains a metal that is less malleable than copper. By providing this heating coil, it aims at providing a reliable rice cooker.

In order to solve the above problems, one aspect of the present disclosure is a heating coil including a winding having a first core wire and a second core wire. The first core wire includes an elongated first conductor and a first insulating layer provided on the surface of the first conductor. The second core wire includes an elongated second conductor, a second insulating layer provided on the surface of the second conductor, and a fusion layer provided on the surface of the second insulating layer.

Another aspect of the present disclosure is a rice cooker including the heating coil.

According to the heating coil of the above aspect, disconnection of the winding in the manufacturing process can be prevented. By providing the heating coil, a highly reliable rice cooker can be provided.

FIG. 1 is an overall perspective view showing an appearance of a heating coil according to an embodiment of the present disclosure. FIG. 2 is a perspective view of the winding of the heating coil in the embodiment. FIG. 3A is a cross-sectional view of the first core wire constituting the winding of the heating coil according to the embodiment. FIG. 3B is a cross-sectional view of the second core wire constituting the winding of the heating coil according to the embodiment. FIG. 4A is a diagram illustrating a state in which the winding of the heating coil according to the embodiment is configured by only the second core wire, and the winding is deformed. FIG. 4B is a diagram illustrating a state in which the winding of the heating coil according to the embodiment is configured by the first core wire and the second core wire, and the winding is deformed. FIG. 5 is a cross-sectional view of the rice cooker according to the embodiment of the present disclosure. FIG. 6A is a cross-sectional view of a wire of a conventional heating coil. FIG. 6B is a cross-sectional view of a conventional heating coil. FIG. 7 is a cross-sectional view of a conventional high-frequency electric wire.

The first aspect of the present disclosure is a heating coil including a winding having a first core wire and a second core wire. The first core wire includes an elongated first conductor and a first insulating layer provided on the surface of the first conductor. The second core wire includes an elongated second conductor, a second insulating layer provided on the surface of the second conductor, and a fusion layer provided on the surface of the second insulating layer. According to this aspect, disconnection of the winding in the manufacturing process of the heating coil can be prevented.

According to the second aspect of the present disclosure, in the first aspect, the number of first core wires is 30% to 50% of the total of the number of first core wires and the number of second core wires. According to this aspect, disconnection of the winding in the manufacturing process of the heating coil can be prevented.

According to the third aspect of the present disclosure, in the first or second aspect, the first conductor is provided on the surface of the first center conductor and the first center conductor provided at the center of the first conductor. And having a diameter of 0.1 to 0.3 mm. The first covering layer has a smaller volume resistance than the first central conductor and has a cross-sectional area of 10 to 20% of the cross-sectional area of the first conductor.

According to this aspect, it is possible to reduce the resistance of the heating coil when a high-frequency current flows, and as a result, it is possible to reduce the loss in the heating coil.

According to the fourth aspect of the present disclosure, in any one of the first to third aspects, the second conductor is provided on the surface of the second central conductor provided on the center of the second conductor and on the surface of the second central conductor. And a second covering layer provided, and has a diameter of 0.1 to 0.3 mm. The second covering layer has a smaller volume resistance than the second central conductor and has a cross-sectional area of 10 to 20% of the cross-sectional area of the second conductor.

According to the fifth aspect of the present disclosure, in any of the first to fourth aspects, the fusion layer has a lower melting point than the first insulating layer and the second insulating layer.

According to this aspect, the winding can be fused by the fusion layer without damaging the first insulation layer and the second insulation layer.

A sixth aspect of the present disclosure is a rice cooker including the heating coil according to any one of the first to fifth aspects. According to this aspect, since the heating coil without a disconnection is used in a manufacturing process, a reliable rice cooker can be provided.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description may be omitted.

[Configuration of heating coil]
A heating coil 1 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 4B. As will be described later, the induction heating cooker according to the present embodiment is a rice cooker 100 (see FIG. 5).

FIG. 1 is a perspective view showing the external appearance of the heating coil 1. FIG. 2 is a perspective view of the winding 2 constituting the heating coil 1. 3A and 3B are cross-sectional views showing the core wire 3 and the core wire 6 constituting the winding 2, respectively.

As shown in FIG. 1, the heating coil 1 is formed by winding one elongate winding 2 in a spiral shape. As shown in FIG. 2, the winding 2 is formed by twisting an assembly wire in which a predetermined number of core wires 3 and a predetermined number of core wires 6 are arranged at a predetermined interval.

As shown in FIG. 3A, the core wire 3 includes an elongated conductor 4 and an insulating layer 5 provided on the surface of the conductor 4. The conductor 4 includes a central conductor 4 a provided at the center of the conductor 4 and a coating layer 4 b provided on the surface of the conductor 4.

As shown in FIG. 3B, the core wire 6 includes an elongated conductor 7, an insulating layer 8 provided on the surface of the conductor 7, and a fusion layer 9 provided on the surface of the insulating layer 8. The conductor 7 includes a central conductor 7 a provided at the center of the conductor 7 and a coating layer 7 b provided on the surface of the conductor 7.

When the assembly wire obtained by twisting the

core wires

3 and 6 is wound around a jig and a high-frequency current is supplied to the assembly wire, the assembly wire generates heat. Due to this heat generation, the fusion layer 9 of the core wire 6 is melted. As a result, the core wire 3 and the core wire 6 are fused to form the winding 2.

The core wire 3 corresponds to the first core wire, and the core wire 6 corresponds to the second core wire. The conductor 4 corresponds to the first conductor, and the conductor 7 corresponds to the second conductor. The insulating layer 5 corresponds to the first insulating layer, and the insulating layer 8 corresponds to the second insulating layer. The center conductor 4a corresponds to the first center conductor, and the center conductor 7a corresponds to the second center conductor. The coating layer 4b corresponds to the first coating layer, and the coating layer 7b corresponds to the second coating layer.

In the induction heating cooker, when a high frequency current of 20 to 100 kHz is supplied to the heating coil, the current concentrates on the surface of the conductor due to the skin effect. Therefore, when the conductor has a central conductor and a coating layer provided on the surface of the central conductor, the resistance value of the coating layer which is the surface portion of the conductor is reduced in order to suppress the heat generation and power consumption of the heating coil. There is a need.

¡To reduce the burden on the user, it is preferable that the weight of a portable household appliance such as a rice cooker is light. In the present embodiment, the

center conductors

4a and 7a are made of a material having a small volume resistance value and a light weight, such as aluminum or aluminum.

The coating layers 4b and 7b are preferably made of a material having a smaller volume resistance than aluminum or an aluminum alloy, for example, a metal such as gold, silver, or copper. In the present embodiment, coating layers 4b and 7b are made of copper.

In the above configuration, the radius of the

conductors

4 and 7, the ratio between the center conductor 4 a and the covering layer 4 b, the ratio between the center conductor 7 a and the covering layer 7 b, and the like are set according to the application of the heating coil 1.

As described above, in the heating coil 1 in which a high frequency current of 20 to 100 kHz flows, the diameters of the

conductors

4 and 7 are preferably set to 0.1 to 0.3 mm, and more preferably set to 0.25 mm. .

The cross-sectional area of the covering layer 4b is preferably set to 10 to 20% of the cross-sectional area of the conductor 4 having the above diameter, and more preferably set to 15%. The conductor 7 is the same as the conductor 4.

With this configuration, the resistance of the heating coil 1 when a high-frequency current flows through the heating coil 1 can be reduced, and loss in the heating coil 1 can be reduced.

The insulating

layers

5 and 8 are preferably made of an F-type or H-type insulating material defined by the Electrical Appliance and Material Safety Law. With this configuration, the

conductors

4 and 7 can be reliably insulated by the insulating

layers

5 and 8, respectively.

In the present embodiment, the fusion layer 9 is preferably composed of a thermoplastic material having a melting point lower than that of the insulating

layers

5 and 8 and higher than the temperature of the heating coil 1 during operation, for example, a polyamide resin. With this configuration, the fusion layer 9 melts at a temperature lower than the melting point of the insulating

layers

5 and 8.

For this reason, in order to bundle the core wire 3 and the core wire 6 to form the winding 2 of the heating coil 1, the insulating

layers

5 and 8 are not damaged when the core wire 3 and the core wire 6 are fused. The

conductors

4 and 7 can be reliably insulated by the

layers

5 and 8, respectively.

Hereinafter, features of the heating coil 1 according to the present embodiment will be described.

As described above, the winding 2 of the heating coil 1 is formed by twisting and fusing together a plurality of core wires 3 that do not include the fusing layer 9 and a plurality of core wires 6 that include the fusing layer 9. .

When the winding 2 is constituted only by the core wire 6 having the fusion layer 9 and the case where the winding 2 is constituted including the core wire 3 not having the fusion layer 9, the winding 2 is The former is more firmly fixed than the latter. For this reason, the change in the cross-sectional shape of the winding 2 when the winding 2 is curved is less in the former than in the latter. Therefore, the

cores

3 and 6 positioned outside the curved winding 2 are extended more greatly in the former than in the latter.

In the present embodiment, the conductor 4 of the core wire 3 includes a central conductor 4a made of aluminum or an aluminum alloy, and a coating layer 4b made of copper. The conductor 7 of the core wire 6 includes a central conductor 7a made of aluminum or an aluminum alloy and a coating layer 7b made of copper. For this reason, if the winding 2 is greatly extended, the

center conductors

4a and 7a having poor expandability may be disconnected.

In the present embodiment, in order to prevent disconnection of the

central conductors

4a and 7a, the winding 2 is configured including not only the core wire 6 having the fusion layer 9 but also the core wire 3 having no fusion layer 9. According to the present embodiment, the coupling force between the core wires can be reduced, and the winding 2 can be formed softer. As a result, disconnection of the winding 2 in the manufacturing process can be prevented.

The following is a more specific explanation. The elongation rate of the curved winding 2 is determined by the bending radius and the distance from the neutral surface to the outer periphery of the curved winding 2. The larger the elongation percentage of the winding 2 is, the larger the winding 2 is stretched and the easier it is to break.

FIG. 4A is a diagram showing a state where the winding 2 including only the core wire 6 is curved. As shown in FIG. 4A, the diameter of the winding 2 is D0, the bending radius of the winding 2 is R1, the distance from the neutral plane F of the winding 2 to the outer periphery of the winding 2 is L1, and the elongation of the winding 2 Is H1, the elongation H1 is expressed by the formula (1).

H1 = L1 / R1 (1)
In the winding 2 having only the core wire 6, since the winding 2 is formed more rigidly, when the winding 2 is bent with a bending radius R1, the cross-sectional shape of the winding 2 hardly changes. Therefore, in this case, the distance L1 from the neutral plane F to the outer periphery of the winding 2 is expressed by Expression (2).

L1 = D0 / 2 (2)
FIG. 4B is a diagram illustrating a state where the winding 2 including the

core wires

3 and 6 is curved. As shown in FIG. 4B, the diameter of the winding 2 is D0, the bending radius of the winding 2 is R1, the distance from the neutral plane F of the winding 2 to the outer periphery of the winding 2 is L2, and the elongation rate of the winding 2 Is H2, the elongation H2 is expressed by the formula (3).

H2 = L2 / R1 (3)
In the case shown in FIG. 4B, the coupling force between the core wires is weaker than in the case shown in FIG. 4A, and the winding 2 is soft. Therefore, when the winding 2 is curved, the cross-sectional shape of the winding 2 is elliptical as shown in FIG. 4B. At this time, if the major axis and minor axis of the winding 2 having a cross-sectional shape are D1 and D2, respectively, the distance L2 from the neutral plane F to the outer periphery of the coil 2 is half of the minor axis D2.

Since the minor diameter D2 is smaller than the diameter D0, the elongation H2 of the winding 2 in the case shown in FIG. 4B is smaller than the elongation H1 of the winding 2 in the case shown in FIG. 4A.

For this reason, when the heating coil 1 is formed using the winding 2 in the case shown in FIG. 4B, the winding 2 is more than in the case where the heating coil 1 is formed using the winding 2 in the case shown in FIG. 4A. It is not stretched greatly. As a result, disconnection of the winding 2 in the manufacturing process can be prevented.

[Ratio of core wire 6 in winding 2]
Hereinafter, the heating coil 1 according to the present embodiment will be described in more detail.

When the ratio of the core wire 6 in the winding 2 is increased, the amount of the fusion layer 9 included in the winding 2 is increased, and the winding 2 is more firmly fixed. As described above, as the winding 2 is firmly fixed, there is a higher possibility that the winding 2 is disconnected when the heating coil 1 is formed.

On the other hand, when the ratio of the core wire 6 in the winding 2 is reduced, the amount of the fusion layer 9 included in the winding 2 is reduced, the coupling force between the core wires is reduced, and the winding 2 is softened. For this reason, the possibility of disconnection in the winding 2 when the heating coil 1 is formed is reduced. However, if the coupling force between the core wires is too low, the

core wires

3 and 6 are not firmly fixed, and the strength of the heating coil 1 is reduced.

Therefore, in order to improve the strength of the heating coil 1 and to prevent the winding 2 from being disconnected, it is necessary to configure the winding 2 with the core wire 3 and the core wire 6 in an appropriate ratio.

Hereinafter, experimental results regarding an appropriate ratio of the core wire 6 included in the winding 2 will be described.

In this experiment, a heating coil 1 formed of a winding 2 having

core wires

3 and 6 having the following configuration is used. The core wire 3 has a conductor 4 having a diameter of 0.25 mm and an insulating layer 5 made of an F-type insulating material. The conductor 4 includes a central conductor 4a made of aluminum or an aluminum alloy, and a coating layer 4b made of copper.

The core wire 6 has a conductor 7 having a diameter of 0.25 mm, an insulating layer 8 made of an F-type insulating material, and a fusion layer 9 made of polyamide resin. The conductor 7 includes a central conductor 7a made of aluminum or an aluminum alloy, and a coating layer 7b made of copper.

In this experiment, the winding 2 having a ratio of the core wire 6 to the total number of the

core wires

3 and 6 of 25% to 55% was bent and stretched 90 degrees a predetermined number of times (for example, 2 or 3 times), The presence or absence of peeling of the core wire in the winding 2 and the presence or absence of disconnection in the winding 2 were confirmed.

Table 1 shows the experimental results. Here, the winding 2 has M core wires 3 and N core wires 6. That is, N / (M + N) shown in Table 1 means the ratio of the core wire 6 to the total number of core wires included in the winding 2.

The evaluation for peeling of the core wire shown in Table 1 is classified into the following three. “◯” evaluation means that the core 2 is not peeled off from the winding 2 before the experiment and the state before the experiment is maintained after the experiment. Prior to the experiment, peeling from the winding 2 was observed on a small part of the core wire, but no further peeling occurred after the experiment, and the case where the state before the experiment is maintained is also evaluated as “◯”.

“△” evaluation means that some peeling of the core wire was observed before the experiment, but no further peeling occurred after the experiment, and the state before the experiment was maintained. An “x” rating means that a number of core wires have already been peeled off prior to the experiment. The winding 2 evaluated as “◯” and “Δ” can be used, but the winding 2 evaluated as “×” cannot be used.

The evaluation for the breakage of the winding 2 shown in Table 1 is classified into the following three. A “◯” evaluation means that there is no surface crack or disconnection after the experiment. The “Δ” evaluation means that cracks are observed on the surface after the experiment, but no breakage has occurred. "X" evaluation means that it was disconnected after the experiment. The winding 2 evaluated as “◯” and “Δ” can be used, but the winding 2 evaluated as “×” cannot be used.

As a result of the above experiment, as shown in Table 1, in order to improve the strength of the heating coil 1 and to prevent the winding 2 from being disconnected, the ratio of the core wire 6 to the total number of core wires included in the winding 2 is It is preferably 30% to 50%, and more preferably 35% to 45%.

For example, in the core wire 3, the cross-sectional area of the insulating layer 5 is more preferably 20% to 70% of the cross-sectional area of the core wire 3. In the core wire 6, the cross-sectional areas of the insulating layer 8 and the fusion layer 9 are more preferably 20% to 70% of the cross-sectional area of the core wire 6.

Thereby, excessive hardening of the winding 2 can be prevented, and disconnection of the winding 2 in the manufacturing process of the heating coil 1 can be further prevented.

[Composition of rice cooker]
Hereinafter, rice cooker 100 according to the present embodiment will be described with reference to FIG. FIG. 5 is a cross-sectional view of the rice cooker 100.

As shown in FIG. 5, the rice cooker 100 includes a main body 10, a lid body 11 that covers the upper surface of the main body 10, and a pan 12 that is detachably accommodated in the main body 10.

The rice cooker 100 has a heating coil 1 configured using the above-described winding 2 inside the main body 10, and by induction heating the pan 12 using the heating coil 1, rice in the pan 12, etc. Cooking food.

As shown in FIG. 1, the rice cooker 100 has a heating coil 1 formed into a shape along the bottom and side surfaces of the pan 12. Thereby, the rice cooker 100 can induction-heat the pot 12 efficiently.

As described above, according to the present embodiment, it is possible to form the heating coil 1 without disconnection in the manufacturing process. By providing the heating coil 1, the rice cooker 100 with high reliability can be provided.

However, the present disclosure is not limited to the above-described embodiment.

The

conductors

4 and 7 may be made of only aluminum or aluminum alloy. With this configuration, an effect equivalent to that of the above-described configuration can be obtained.

The surfaces of the conductor 4 and the conductor 7 may be covered with nickel or tin. With this configuration, it is possible to obtain the same effect as the above-described configuration, and to improve the workability of the heating coil 1 such as solder wettability.

The heating coil according to the present disclosure is applicable not only to induction heating cookers but also to induction heating devices in general.

1,200 Heating coil 2

Winding

3, 6

Core wire

4, 7, 202

Conductor

4a, 7a, 301

Central conductor

4b, 7b, 303

Cover layer

5, 8, 203 Insulating

layer

9, 204 Fusion layer 10 Main body 11 Lid 12 Hot pot 100 Rice cooker 302 Intermetallic compound layer

Claims

A heating coil with windings,
The winding has a first core wire and a second core wire,
The first core wire includes an elongated first conductor and a first insulating layer provided on a surface of the first conductor,
The said 2nd core wire is a heating coil containing the elongate 2nd conductor, the 2nd insulating layer provided in the surface of the said 2nd conductor, and the melt | fusion layer provided in the surface of the said 2nd insulating layer.
The heating coil according to claim 1, wherein the number of the first core wires is 30% to 50% of the total number of the first core wires and the second core wires.
The first conductor includes a first center conductor provided at the center of the first conductor and a first coating layer provided on the surface of the first center conductor, and has a diameter of 0.1 to 0.3 mm. Have
The heating coil according to claim 1, wherein the first covering layer has a volume resistance smaller than that of the first central conductor and has a cross-sectional area of 10 to 20% of a cross-sectional area of the first conductor.
The second conductor includes a second center conductor provided at the center of the second conductor and a second coating layer provided on the surface of the second center conductor, and has a diameter of 0.1 to 0.3 mm. Have
The heating coil according to claim 1, wherein the second covering layer has a volume resistance smaller than that of the second central conductor, and has a cross-sectional area of 10 to 20% of a cross-sectional area of the second conductor.
The heating coil according to claim 1, wherein the fusion layer has a lower melting point than the first insulating layer and the second insulating layer.
A rice cooker comprising the heating coil according to claim 1.