JP3941500B2

JP3941500B2 - Induction heating device

Info

Publication number: JP3941500B2
Application number: JP2001396399A
Authority: JP
Inventors: 敏弘慶島; 章片岡; 勝行相原; 泉生弘田; 信芳槙尾; 和也後藤
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2001-12-27
Filing date: 2001-12-27
Publication date: 2007-07-04
Anticipated expiration: 2021-12-27
Also published as: JP2003197362A

Description

【０００１】
【発明の属する技術分野】
本発明は誘導加熱調理器に代表されるような誘導加熱装置に関するものである。
【０００２】
【従来の技術】
従来の誘導加熱調理器の概略構成について図９を用いて説明する。１は誘導加熱調理器の外郭を構成する本体、２は本体１上に設けたトッププレート、３は加熱コイル、４は加熱コイル３を制御する制御部であり、５は加熱コイル３に対応してトッププレート２に設けた加熱部に載置した鍋等の被加熱体である。加熱コイル３は、直径約０．３ｍｍ程度の素線を数十本撚り合わされて構成され、それぞれの素線は渦巻状に巻回しながら、螺旋状に周回している。
【０００３】
この構成において、加熱コイル３から高周波磁界を発生させ、これを被加熱体５に与えて渦電流を生じさせ、渦電流損に基づく自己発熱により被加熱体５が加熱される。
【０００４】
【発明が解決しようとする課題】
しかしながら、前記従来の構成では誘導加熱調理器の高出力化に対して不十分であった。
【０００５】
誘導加熱の高出力化を図る１つの手段としては、磁界の強さを大きくすることで被加熱体に生じる渦電流を大きくする方法がある。磁界の強さは加熱コイルに流れる電流と加熱コイルの巻き数の積に比例するのでどちらかのファクターを大きくすればよい。
【０００６】
しかしながら、加熱コイルに流れる電流を大きくすれば、加熱コイル自体の発熱が大となるので、電流を大きくするのには一定の限度がある。また、鍋等の被加熱体の径以上に加熱コイルの径を大きくすることはできないので、巻き数を増やすためには必然的に複層巻きになってくる。
【０００７】
加熱コイルの内側と外側の線間は高電圧差であり、複層巻きにすると隣接するコイル導線同士の電圧差が大きくなってくる。特に乱れた状態で巻き回すと、図１０に示すように本来外側にあるコイル導線が内側に入ってくるなどで所々に電圧差が大きくなる箇所が発生し、耐電圧に対する信頼性が低下することになる。
【０００８】
また、複層巻きにすると近接効果による高周波抵抗の増大と冷却される表面積の減少によって放熱性の悪化を招く。ここでいう近接作用とは、近接した導体に電流が流れるときに、磁界を介して相互に影響を与えあって、電流分布に偏りが生じる現象であり、導線表面の実効的な抵抗増大となる。近接作用は高周波電流の向きが導線間で揃っているほど、導線間の間隔が小さいほど、周波数が高くなるほど大きくなる。
【０００９】
本発明は前記従来の課題を解決するもので、高出力で、かつ、加熱コイルの耐電圧に対する信頼性を向上した誘導加熱装置を提供することを目的とする。
【００１０】
【課題を解決するための手段】
前記従来の課題を解決するために、本発明の誘導加熱装置は所定の径でコイル導線を縦１段と縦２段とで交互に繰り返し巻回して形成した加熱コイルを備え、前記コイル導線は、素線を束ねまたは撚り合わせて集合して形成されかつ断面円形状とした集合線と、前記集合線の外周に融点の異なる２種類の樹脂で構成された絶縁体とを有し、前記絶縁体は、融点の低いフッソ樹脂を融点の高いフッソ樹脂の外側に設けて構成され、前記加熱コイルは、前記加熱コイル作成の途中段階においてまたは前記加熱コイル巻回後、前記絶縁体を加熱して前記絶縁体を溶融させ固化させることにより前記絶縁体と絶縁体とを固着して形状を安定化するとともに、前記加熱コイルに４０ｋＨｚ以上の高周波電流を流してアルミや銅等の低抵抗で低透磁率の被加熱体を誘導加熱する構成とした。
【００１１】
この構成により、アルミおよび銅等の低抵抗で低透磁率の被加熱体を加熱することが容易になる。
【００１２】
【発明の実施の形態】
請求項１に記載の発明は、所定の径でコイル導線を縦１段と縦２段とで交互に繰り返し巻回して形成した加熱コイルを備え、前記コイル導線は、素線を束ねまたは撚り合わせて集合して形成されかつ断面円形状とした集合線と、前記集合線の外周に融点の異なる２種類の樹脂で構成された絶縁体とを有し、前記絶縁体は、融点の低いフッソ樹脂を融点の高いフッソ樹脂の外側に設けて構成され、前記加熱コイルは、前記加熱コイル作成の途中段階においてまたは前記加熱コイル巻回後、前記絶縁体を加熱して前記絶縁体を溶融させ固化させることにより前記絶縁体と絶縁体とを固着して形状を安定化するとともに、前記加熱コイルに４０ｋＨｚ以上の高周波電流を流してアルミや銅等の低抵抗で低透磁率の被加熱体を誘導加熱する構成とする。
【００１５】
交互に縦段数を変えることでコイル導線同士磁界を介して相互に影響する近接作用が低減し、加熱コイルの高周波抵抗を下げることができ、加熱コイルの発熱を低減し、かつ、交互に縦段数が変わることで、冷却される表面積が増え、加熱コイルの内部まで冷却風が入り込み冷却性能がより向上する。その上、巻き回し方が乱れていないため、隣接するターン間の電圧差が一定となり、加熱コイルの耐電圧に対する信頼性が向上する。
【００１６】
また、１段、２段、１段と繰り返す構成とすることにより、複層巻きとしては最もコイル導線同士磁界を介して相互に影響する近接作用が低減し、加熱コイルの高周波抵抗を下げることができ、加熱コイルの発熱が低減し、かつ、交互に縦段数が変わることで、冷却される表面積が増え、加熱コイルの内部まで冷却風が入り込み冷却性能がより向上する。
【００１９】
また、コイル導線の断面形状を円形とすることにより、同一断面積の他の形状に比べ、コイル導線同士磁界を介して相互に影響する近接作用が低減し、加熱コイルの高周波抵抗を下げることができ、加熱コイルの発熱が低減するとともに、放熱性、結合強度の観点で最も適したものにすることができる。
【００２０】
また、コイル導線の外周に融点の異なる２種類の樹脂から構成した絶縁体を設け、前記絶縁体は、融点の低いフッソ樹脂を融点の高いフッソ樹脂の外側に設けて構成され、前記加熱コイルは、前記加熱コイル作成の途中段階においてまたは前記加熱コイル巻回後、前記絶縁体を加熱して前記絶縁体を溶融させ固化させることにより前記絶縁体と前記絶縁体とを固着して形状を安定化することにより、コイル導線間の近接作用による高周波抵抗の増大を低減できるとともに、コイル導線間の絶縁強度が向上し、安定した絶縁性を実現し、加熱接着性を向上させ、信頼性を高めことができる。また、加熱コイルに４０ｋＨｚ以上の高周波電流を流して被加熱体を誘導加熱する構成とすることにより、本発明によれば高周波抵抗を低減できるため、アルミおよび銅等の低抵抗で低透磁率の被加熱体を加熱することが容易になる。
【００２２】
請求項２に記載の発明は、２段、３段、２段と繰り返す構成とすることにより、コイル導線どうしの結合強度が増し、通電時加熱コイル自体がびびり振動を発生させ、騒音を悪化させることがない。
【００２３】
【実施例】
以下、本発明の実施例及び参考例については、誘導加熱装置の例として誘導加熱調理器をあげ、図面を参照しながら説明する。
【００２４】
（参考例１）
まず、誘導加熱調理器の概略構成について図１を用いて説明する。１１は誘導加熱調理器の外郭を構成する本体、１２は本体１１上に設けたトッププレート、１３は加熱コイル、１４は加熱コイル１３を制御する制御部であり、１５は加熱コイル１３に対応してトッププレート１２に設けた加熱部に載置した鍋等の被加熱体である。
【００２５】
加熱コイル１３は所定の径でコイル導線１６を２段で内側から外側まで巻き回している。また、コイル導線１６は素線もしくは素線を束ねまたは撚り合わせて集合した集合線から形成されている。
【００２６】
この構成において、加熱コイル１３から高周波磁界を発生させ、これを被加熱体１５に与えて渦電流を生じさせ、渦電流損に基づく自己発熱により被加熱体１５が加熱される。
【００２７】
上記構成により、複層巻きにして巻き数を増やして磁界の強さを大きくし、高出力化が可能になる。加熱コイル１３に流れる電流については許容される範囲で大きくすれば、最大限高出力化が可能である。また、巻き回し方が乱れていないため、隣接するターン間の電圧差が一定となり、加熱コイル１３の耐電圧に対する信頼性が向上する。
【００２８】
また、加熱コイル１３を同じ段数で内側から外側まで巻き回しているため、加熱コイル１３の厚みが一定になり、作製しやすい形状となる。
【００２９】
特に加熱コイル１３を２段で構成しているので、コイル導線１６同士磁界を介して相互に影響する近接作用が低減し、加熱コイル１３の高周波抵抗を下げることができ、加熱コイル１３の発熱を低減し、加熱コイル自体も扁平形状になり３段以上の加熱コイル１３に対する相対的な放熱面積を大きくでき、冷却性能を向上させることができる。
【００３０】
なお、図１のように本参考例では縦段数を２段で内側から外側まで巻き回しているが、２段に限らず同段数であれば、製作しやすい形状となる。また、隣接した径を異なる段数で巻き回してもよく、要は巻き回し方が乱れずに複層巻きにすればよい。
【００３１】
（実施例１）
次に実施例１について図２を用いて説明する。図２では加熱コイル１３は２段、１段、２段と繰り返す構成になっている。また、コイル導線１６は素線もしくは素線を束ねまたは撚り合わせて集合した集合線から形成されている。
【００３２】
上記構成により、複層巻きにして巻き数を増やして磁界の強さを大きくし、高出力化が可能になる。また、交互に縦段数を変えることでコイル導線１６同士磁界を介して相互に影響する近接作用が低減し、加熱コイル１３の高周波抵抗を下げることができ、加熱コイル１３の発熱を低減し、かつ、交互に縦段数が変わることで、冷却される表面積が増え、加熱コイル１３の内部まで冷却風が入り込み冷却性能がより向上する。さらに、交互に縦段数を変えることで、単位体積当たりの巻き数を増やすことができる。その上、巻き回し方が乱れていないため、隣接するターン間の電圧差が一定となり、加熱コイル１３の耐電圧に対する信頼性が向上する。加熱コイル１３に流れる電流については許容される範囲で大きくすれば、最大限高出力化が可能である。
【００３３】
特に２段、１段、２段と繰り返す構成とすることにより、複層巻きとしては最もコイル導線１６同士磁界を介して相互に影響する近接作用が低減し、加熱コイル１３の高周波抵抗を下げることができ、加熱コイル１３の発熱が低減し、冷却性能がより向上する。
【００３４】
なお、図２のように本実施例では最内径を２段としたが、最内径を１段としてもよく、要は交互に段数を変えればよい。また、縦段数は本実施例のように２段、１段、２段に限るものではなく、交互に１段づつ縦段数が変わる構成であれば、同様の効果が得られる。
【００３５】
（実施例２）
次に実施例２について図３を用いて説明する。図２では加熱コイル１３は２段、３段、２段と繰り返す構成になっている。
【００３６】
上記構成により、複層巻きにして巻き数を増やして磁界の強さを大きくし、高出力化が可能になる。また、交互に縦段数を変えることでコイル導線１６同士磁界を介して相互に影響する近接作用が低減し、加熱コイル１３の高周波抵抗を下げることができ、加熱コイル１３の発熱が低減し、かつ、交互に縦段数が変わることで、冷却される表面積が増え、加熱コイル１３の内部まで冷却風が入り込み冷却性能がより向上する。
【００３７】
特にｎを２として、２段、３段、２段と繰り返す構成とすることにより、コイル導線１６同士の結合強度が増し、通電時加熱コイル１３自体がびびり振動を発生させ、騒音を悪化させることがない。
【００３８】
高出力化のためには、単純に巻き数を増やせばよいが、あまり巻き数を増やしすぎると、つまり、ｎを大きくしすぎるとコイル導線１６同士磁界を介して相互に影響されやすくなり高周波抵抗が増大する。さらに、加熱コイル１３の内部に熱がこもりやすくなり放熱性が悪化するので、ｎは２以下で設計するのが最もバランスがよい。
【００３９】
なお、図３のように本実施例では最内径を３段、最外径を２段としたが、最内径を２段、最外径を３段としてもよく、要は交互に段数を変えればよい。
【００４０】
（参考例２）
次に参考例２について図４を用いて説明する。図４では加熱コイル１３の内周部１７もしくは／および外周部１８を加熱コイル１３の上面の高さを揃えるように単層巻きにしている。
【００４１】
上記構成により、特に磁束が集中しやすい内周部１７と外周部１８での高周波抵抗を下げることができ、加熱コイル１３の発熱が低減し、冷却性能が向上する。
【００４２】
（実施例３）
次に実施例３について図５を用いて説明する。図５はコイル導線１６の断面形状を比較した一例である。円形は方形に比べ、コイル導線１６どうしの中心距離が長く、コイル導線１６どうしの接触は点接触なので、コイル導線１６どうし磁界を介して相互に影響する近接作用が低減し、加熱コイル１３の高周波抵抗を下げることができ、加熱コイル１３の発熱が低減する。また、冷却される表面積が大きく、加熱コイル１３の内部まで冷却風が入り込み放熱性がよい。また、結合のバランスもよい。したがって、コイル導線１６の断面形状は以上の観点で最も適したものになる。
【００４３】
（実施例４）
次に実施例４について図６を用いて説明する。図６では低温で揮発する物質をなくしたり、予め熱を加え揮発する物質をなくしたコイル導線１６の外周に押し出し成形にて絶縁体１９を設けている。
【００４４】
上記構成により、コイル導線１６間の間隔が大きくなり、近接作用による高周波抵抗の増大を低減できるとともに、コイル導線１６間の絶縁強度が向上し、信頼性を高めることができる。また、コイル導線１６の巻き回したターン間の電圧差は大きいため、結果として絶縁体１９をターン間に設けるこの方式は絶縁の信頼性が高い。したがって、本実施例で示すような複層巻きの加熱コイル１３は隣接するターン間の電圧差が大きくなるため、この構成は非常に効果的である。
【００４５】
一般にコイル導線１６同士を結合させる方法としては、図７に示す自己融着線を用いる方法が一般的に行われている。すなわち、導体２０の周囲に絶縁層２１を設け、さらにその外側に融着層２２を設けた素線を用いて加熱コイル１３を作製し、その後加熱することにより融着層２２を溶融固化することにより、素線間を固着して加熱コイル１３の形状を安定に保持できるようにする方法である。
【００４６】
本実施例ではコイル導線１６の外周に絶縁体１９を設けているので、この絶縁体１９を利用することにより素線の融着層２２を用いないで加熱コイル１３の形状を安定に保持するようにすることができる。すなわち、絶縁体１９としてポリアミド樹脂、ポリアミドイミド樹脂、ポリエステル樹脂、フッ素樹脂などの熱可塑性樹脂を用い、加熱コイル１３を作製の途中段階において、もしくは加熱コイル１３を巻回後、熱可塑性樹脂を加熱して溶融させ固化させることにより、絶縁体１９と絶縁体１９あるいは絶縁体１９と素線とを固着させ加熱コイル１３の形状を安定化させることができる。また、絶縁体１９を融点の異なる２種類の樹脂から構成し、融点の低い樹脂を融点の高い樹脂の外側に構成することで加熱接着性を向上することができる。例えば、絶縁体１９にフッ素樹脂を用い、外側に融点の低いフッ素樹脂（ＥＴＦＥやＦＥＰ）を用い、内側に融点の高いフッ素樹脂（ＰＦＡ）を用いると安定した絶縁性と加熱接着性を向上させることができる。
【００４７】
さらに、絶縁体１９として未硬化もしくは半硬化のゴムまたは熱硬化性の樹脂を用い、加熱コイル１３を作製の途中段階において、もしくは加熱コイル１３を巻き回し後、加熱固化させることにより、絶縁体１９と絶縁体１９あるいは絶縁体１９と素線とを固着させ加熱コイル１３の形状を安定化させることができる。
【００４８】
なお、ゴムとしてはシリコン系、フッ素系などのものが、また、熱効果樹脂としてはエポキシ樹脂、不飽和ポリエステル樹脂、フェノール樹脂などが用いられる。
【００４９】
また、図８に示すように予め熱を加えコイル導線１６自体に有している揮発成分を低減した後、コイル導線１６の外周に絶縁体１９を設け、さらにその外側に接着層２３を設けるようにしてもよい。ここでいう接着層は融着層を含む。この構成のコイル導線１６を巻き回し後、加熱することによりコイル導線１６とコイル導線１６とが固着し形状の安定した加熱コイル１３を得ることができる。
【００５０】
なお、絶縁材料の耐熱性は設計により必要とする耐熱区分の中から選択すればよい。また、本実施例においては、押し出し成形でコイル導線１６の周囲に絶縁体１９を設けたが、ディッピング方式等でもよく、要は、コイル導線１６の周囲に絶縁体１９を設ければよい。
【００５１】
また、素線の導体部の直径を０．１ｍｍ以下にすれば、コイル導線１６内の表皮効果の影響が低減し、加熱コイル１３の高周波抵抗を下げることができ、加熱コイル１３の発熱が低減し、冷却性能が向上するので、複層巻きとし高周波抵抗が増大しやすい本構成の場合、非常に効果がある。
【００５２】
さらに、本構成は加熱コイル１３の巻き数を大にしても高周波抵抗を低減できるため、特に４０ｋＨｚ以上の高周波になると効果的であり、また、アルミおよび銅等の低抵抗で低透磁率の被加熱体１５の場合、加熱周波数を約４０ｋＨｚ以上にすることが適しており、アルミや銅等の非磁性金属を加熱することが容易になる。
【００５３】
なお、本実施例は誘導加熱装置の例として誘導加熱調理器にて説明したが、その他各種誘導加熱装置においても同様の効果が得られる。
【００５４】
【発明の効果】
以上のように、本発明によれば、高出力で、かつ、加熱コイルの耐電圧に対する信頼性を向上した誘導加熱装置を得ることができる。
【図面の簡単な説明】
【図１】本発明の参考例１における誘導加熱調理器の構成断面図
【図２】本発明の実施例１における誘導加熱調理器の構成断面図
【図３】本発明の実施例２における誘導加熱調理器の構成断面図
【図４】本発明の参考例２における加熱コイルの断面図
【図５】（ａ）本発明の実施例３におけるコイル導線断面形状が円形の場合を示す図
（ｂ）同、コイル導線断面形状が方形の場合を示す図
【図６】本発明の実施例４におけるコイル導線の断面図
【図７】素線の断面図
【図８】本発明の実施例４における他例のコイル導線の断面図
【図９】従来の誘導加熱調理器の構成断面図
【図１０】同、誘導加熱調理器の加熱コイルの断面図
【符号の説明】
１３加熱コイル
１６コイル導線
１７内周部
１８外周部
１９絶縁体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating apparatus represented by an induction heating cooker.
[0002]
[Prior art]
A schematic configuration of a conventional induction heating cooker will be described with reference to FIG. Reference numeral 1 denotes a main body constituting the outer shell of the induction heating cooker, 2 a top plate provided on the main body 1, 3 a heating coil, 4 a control unit for controlling the heating coil 3, and 5 corresponding to the heating coil 3. The heated body such as a pan placed on the heating unit provided on the top plate 2. The heating coil 3 is formed by twisting dozens of strands having a diameter of about 0.3 mm, and each strand is spirally wound while being wound in a spiral shape.
[0003]
In this configuration, a high frequency magnetic field is generated from the heating coil 3 and applied to the heated body 5 to generate an eddy current, and the heated body 5 is heated by self-heating based on the eddy current loss.
[0004]
[Problems to be solved by the invention]
However, the conventional configuration is insufficient for increasing the output of the induction heating cooker.
[0005]
One means for increasing the output of induction heating is to increase the eddy current generated in the heated object by increasing the strength of the magnetic field. Since the strength of the magnetic field is proportional to the product of the current flowing through the heating coil and the number of turns of the heating coil, either factor may be increased.
[0006]
However, if the current flowing through the heating coil is increased, the heating coil itself generates more heat, so there is a certain limit to increasing the current. Further, since the diameter of the heating coil cannot be made larger than the diameter of the heated object such as a pan, in order to increase the number of windings, it is inevitably a multilayer winding.
[0007]
There is a high voltage difference between the inner and outer wires of the heating coil, and when a multi-layer winding is used, the voltage difference between adjacent coil conductors increases. In particular, when winding in a distorted state, as shown in FIG. 10, there are places where the voltage difference increases in some places, such as when the coil conductor wire that is originally on the inside enters inside, and reliability withstand voltage decreases. become.
[0008]
In addition, when the multi-layer winding is used, heat dissipation is deteriorated due to an increase in high-frequency resistance due to the proximity effect and a decrease in the surface area to be cooled. 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 effect increases as the direction of the high-frequency current is aligned between the conductors, the distance between the conductors is smaller, and the frequency is higher.
[0009]
SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide an induction heating apparatus that has high output and improved reliability with respect to the withstand voltage of a heating coil.
[0010]
[Means for Solving the Problems]
In order to solve the conventional problem, the induction heating apparatus of the present invention includes a heating coil formed by alternately and repeatedly winding a coil conductor with a predetermined diameter in a first stage and a second stage, and the coil conductor comprises: An assembly line formed by bundling or twisting strands and having a circular cross section, and an insulator composed of two types of resins having different melting points on the outer periphery of the assembly line, The body is configured by providing a low melting point fluororesin on the outside of the high melting point fluororesin, and the heating coil heats the insulator at an intermediate stage of the heating coil creation or after the heating coil is wound. By melting and solidifying the insulator, the insulator and the insulator are fixed to stabilize the shape, and a high-frequency current of 40 kHz or higher is passed through the heating coil to reduce resistance and low permeability such as aluminum or copper. Magnetic permeability It has a structure you induction heating heat body.
[0011]
With this configuration, it becomes easy to heat a heated object having a low resistance and a low magnetic permeability such as aluminum and copper .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 includes a heating coil formed by alternately winding a coil conductor with a predetermined diameter in a vertical stage and a vertical stage, and the coil conductor bundles or twists strands. And an assembly made of two types of resins having different melting points on the outer periphery of the assembly line, and the insulator is a fluororesin having a low melting point. Is provided outside the fluororesin having a high melting point, and the heating coil heats the insulator to melt and solidify the insulator in the middle of the heating coil production or after the heating coil is wound. As a result, the insulator and the insulator are fixed to stabilize the shape, and a high-frequency current of 40 kHz or more is passed through the heating coil to inductively heat the object to be heated with low resistance such as aluminum or copper. you and to that configuration
[0015]
Exchange via the coil wire between the magnetic field proximity effect is reduced to interact each other by changing the vertical stages, it is possible to reduce the high frequency resistance of the heating coil, to reduce the heat generation of the heating coils, and the vertical alternately By changing the number of stages, the surface area to be cooled increases, cooling air enters the inside of the heating coil, and the cooling performance is further improved . On the its, for how wound is not disturbed, becomes a voltage difference between adjacent turns is constant, reliability is improved with respect to the withstand voltage of the heating coil.
[0016]
In addition , by adopting a configuration that repeats one step, two steps, and one step, the proximity effect that affects each other via the magnetic field between the coil conductors is reduced as the multi-layer winding, and the high-frequency resistance of the heating coil is reduced. In addition, since the heat generation of the heating coil is reduced and the number of vertical stages is alternately changed, the surface area to be cooled is increased, and cooling air enters the inside of the heating coil to further improve the cooling performance.
[0019]
In addition , by making the cross-sectional shape of the coil conductor round, compared to other shapes with the same cross-sectional area, the proximity effect that affects each other via the magnetic field between the coil conductors is reduced, and the high-frequency resistance of the heating coil is reduced. It is possible to reduce the heat generation of the heating coil and to make it most suitable in terms of heat dissipation and coupling strength.
[0020]
In addition , an insulator composed of two types of resins having different melting points is provided on the outer periphery of the coil lead wire, and the insulator is configured by providing a fluorine resin having a low melting point outside the fluorine resin having a high melting point, and the heating coil In the middle of making the heating coil or after winding the heating coil, the insulator is heated to melt and solidify the insulator, thereby fixing the insulator and the insulator to stabilize the shape. As a result, the increase in high-frequency resistance due to the proximity effect between the coil conductors can be reduced, the insulation strength between the coil conductors can be improved, stable insulation can be realized, heating adhesion can be improved, and reliability can be improved. Can do. In addition, since the high-frequency resistance can be reduced according to the present invention by adopting a configuration in which a high-frequency current of 40 kHz or more is passed through the heating coil to inductively heat the object to be heated, low resistance and low magnetic permeability such as aluminum and copper can be achieved. It becomes easy to heat the object to be heated.
[0022]
According to the second aspect of the present invention, the coupling strength between the coil conductors is increased by repeating the structure in two steps, three steps, and two steps, and the heating coil itself generates chatter vibration when energized to deteriorate noise. There is nothing.
[0023]
【Example】
Hereinafter, examples and reference examples of the present invention will be described with reference to the drawings, taking an induction heating cooker as an example of the induction heating device.
[0024]
( Reference Example 1)
First, a schematic configuration of the induction heating cooker will be described with reference to FIG. Reference numeral 11 denotes a main body that forms the outline of the induction heating cooker, 12 is a top plate provided on the main body 11, 13 is a heating coil, 14 is a control unit that controls the heating coil 13, and 15 corresponds to the heating coil 13. The heated body such as a pan placed on the heating unit provided on the top plate 12.
[0025]
The heating coil 13 has a predetermined diameter and a coil conductor 16 wound in two steps from the inside to the outside. In addition, the coil conductor 16 is formed of an element wire or an assembly wire in which element wires are bundled or twisted together.
[0026]
In this configuration, a high frequency magnetic field is generated from the heating coil 13 and applied to the heated body 15 to generate an eddy current, and the heated body 15 is heated by self-heating based on the eddy current loss.
[0027]
With the above configuration, it is possible to increase the number of turns by increasing the number of turns in a multi-layer winding, thereby increasing the output. If the current flowing through the heating coil 13 is increased within an allowable range, the maximum output can be increased. Moreover, since the winding method is not disturbed, the voltage difference between adjacent turns is constant, and the reliability of the heating coil 13 with respect to the withstand voltage is improved.
[0028]
Moreover, since the heating coil 13 is wound from the inner side to the outer side with the same number of steps, the thickness of the heating coil 13 is constant, and the shape is easy to manufacture.
[0029]
In particular, since the heating coil 13 is configured in two stages, the proximity effect that affects each other via the magnetic field between the coil conductors 16 can be reduced, the high-frequency resistance of the heating coil 13 can be reduced, and the heating coil 13 can generate heat. Thus, the heating coil itself is flattened, the heat radiation area relative to the three or more heating coils 13 can be increased, and the cooling performance can be improved.
[0030]
As shown in FIG. 1, in this reference example, the number of vertical stages is two, and the winding is wound from the inner side to the outer side. Further, the adjacent diameters may be wound with different numbers of stages, and in short, the winding method may be multi-layered without disturbing the winding method.
[0031]
(Example 1 )
Next, Example 1 will be described with reference to FIG. In FIG. 2, the heating coil 13 is configured to repeat two steps, one step, and two steps. In addition, the coil conductor 16 is formed of an element wire or an assembly wire in which element wires are bundled or twisted together.
[0032]
With the above configuration, it is possible to increase the number of turns by increasing the number of turns in a multi-layer winding, thereby increasing the output. Further, by alternately changing the number of vertical stages, the proximity effect that affects each other via the magnetic field between the coil conductors 16 can be reduced, the high-frequency resistance of the heating coil 13 can be lowered, the heat generation of the heating coil 13 can be reduced, and By alternately changing the number of vertical stages, the surface area to be cooled is increased, and cooling air enters the heating coil 13 to further improve the cooling performance. Furthermore, the number of windings per unit volume can be increased by alternately changing the number of vertical stages. In addition, since the winding method is not disturbed, the voltage difference between adjacent turns becomes constant, and the reliability of the heating coil 13 with respect to the withstand voltage is improved. If the current flowing through the heating coil 13 is increased within an allowable range, the maximum output can be increased.
[0033]
In particular, by adopting a configuration that repeats two stages, one stage, and two stages, the multi-layer winding reduces the proximity effect that most affects the coil conductors 16 via the magnetic field, and lowers the high-frequency resistance of the heating coil 13. The heat generation of the heating coil 13 is reduced, and the cooling performance is further improved.
[0034]
As shown in FIG. 2, the innermost diameter is two in this embodiment, but the innermost diameter may be one, and the number of stages may be changed alternately. Further, the number of vertical stages is not limited to two, one, or two as in this embodiment, and the same effect can be obtained if the number of vertical stages is changed alternately by one stage.
[0035]
(Example 2 )
Next, Example 2 will be described with reference to FIG. In FIG. 2 , the heating coil 13 is configured to repeat two steps, three steps, and two steps.
[0036]
With the above configuration, it is possible to increase the number of turns by increasing the number of turns in a multi-layer winding, thereby increasing the output. Further, by alternately changing the number of vertical stages, the proximity effect that affects each other via the magnetic field between the coil conductors 16 can be reduced, the high-frequency resistance of the heating coil 13 can be lowered, the heat generation of the heating coil 13 is reduced, and By alternately changing the number of vertical stages, the surface area to be cooled is increased, and cooling air enters the heating coil 13 to further improve the cooling performance.
[0037]
In particular, by setting n to 2 and repeating the structure in two steps, three steps, and two steps, the coupling strength between the coil conductors 16 increases, and the heating coil 13 itself generates chatter vibration when energized, thereby deteriorating noise. There is no.
[0038]
In order to increase the output, it is sufficient to simply increase the number of turns. However, if the number of turns is increased too much, that is, if n is increased too much, the coil conductors 16 are easily affected by the magnetic field between each other and the high frequency resistance. Will increase. Furthermore, since heat tends to be trapped inside the heating coil 13 and heat dissipation is deteriorated, it is best to design n to be 2 or less.
[0039]
As shown in FIG. 3, in this embodiment, the innermost diameter is three steps and the outermost diameter is two steps. However, the innermost diameter may be two steps and the outermost diameter may be three steps, and the number of steps can be changed alternately. That's fine.
[0040]
( Reference Example 2 )
Next, Reference Example 2 will be described with reference to FIG. In FIG. 4, the inner peripheral portion 17 and / or the outer peripheral portion 18 of the heating coil 13 are wound in a single layer so that the height of the upper surface of the heating coil 13 is made uniform.
[0041]
With the above configuration, it is possible to reduce the high-frequency resistance at the inner peripheral portion 17 and the outer peripheral portion 18 where magnetic flux is particularly likely to concentrate, thereby reducing the heat generation of the heating coil 13 and improving the cooling performance.
[0042]
(Example 3 )
Next, Example 3 will be described with reference to FIG. FIG. 5 is an example in which the cross-sectional shapes of the coil conductors 16 are compared. Round compared to a square, the center distance and if the coil conductor 16 is long, the contact of and how the coil conductor 16 is a point contact, reducing proximity effects affecting each other via what was field coil conductor 16, the high frequency heating coil 13 The resistance can be lowered, and the heat generation of the heating coil 13 is reduced. Moreover, the surface area to be cooled is large, and cooling air enters the inside of the heating coil 13 so that heat dissipation is good. Moreover, the balance of coupling is also good. Accordingly, the cross-sectional shape of the coil conductor 16 is most suitable from the above viewpoint.
[0043]
(Example 4 )
Next, Example 4 will be described with reference to FIG. In FIG. 6, the insulator 19 is provided by extrusion molding on the outer periphery of the coil conductor 16 from which a substance that volatilizes at a low temperature is eliminated or a substance that volatilizes by heating in advance is eliminated.
[0044]
With the above configuration, the spacing between the coil conductors 16 is increased, and an increase in high-frequency resistance due to the proximity action can be reduced, and the insulation strength between the coil conductors 16 can be improved and the reliability can be increased. Further, since the voltage difference between the turns of the coil conductor 16 is large, as a result, this method in which the insulator 19 is provided between the turns has high insulation reliability. Therefore, the multi-layered heating coil 13 as shown in the present embodiment has a large voltage difference between adjacent turns, and this configuration is very effective.
[0045]
In general, as a method of coupling the coil conductors 16, a method using a self-bonding wire shown in FIG. 7 is generally performed. That is, the heating coil 13 is produced using a wire having an insulating layer 21 provided around the conductor 20 and further provided with a fusion layer 22 outside thereof, and then the fusion layer 22 is melted and solidified by heating. Thus, the wire is fixed between the wires so that the shape of the heating coil 13 can be stably maintained.
[0046]
In this embodiment, since the insulator 19 is provided on the outer periphery of the coil conductor 16, the shape of the heating coil 13 can be stably maintained by using the insulator 19 without using the fusion layer 22 of the strands. Can be. That is, a thermoplastic resin such as a polyamide resin, a polyamideimide resin, a polyester resin, or a fluororesin is used as the insulator 19, and the thermoplastic resin is heated in the middle of manufacturing the heating coil 13 or after the heating coil 13 is wound. Then, by melting and solidifying, the insulator 19 and the insulator 19 or the insulator 19 and the strand can be fixed and the shape of the heating coil 13 can be stabilized. Moreover, the heat bondability can be improved by configuring the insulator 19 from two types of resins having different melting points and configuring a resin having a low melting point outside the resin having a high melting point. For example, when a fluororesin is used for the insulator 19, a fluororesin having a low melting point (ETFE or FEP) is used on the outside, and a fluororesin having a high melting point (PFA) is used on the inside, the stable insulation and heat adhesion are improved. be able to.
[0047]
Further, an uncured or semi-cured rubber or a thermosetting resin is used as the insulator 19, and the insulator 19 is heated and solidified in the middle of manufacturing the heating coil 13 or after the heating coil 13 is wound. Further, the shape of the heating coil 13 can be stabilized by fixing the insulator 19 or the insulator 19 and the wire.
[0048]
As the rubber, silicon-based, fluorine-based, etc. are used, and as the thermal effect resin, epoxy resin, unsaturated polyester resin, phenol resin, or the like is used.
[0049]
Further, as shown in FIG. 8, after heat is applied in advance to reduce the volatile components of the coil conductor 16 itself, an insulator 19 is provided on the outer periphery of the coil conductor 16, and an adhesive layer 23 is provided on the outer side thereof. It may be. The adhesive layer here includes a fusion layer. When the coil conductor 16 having this configuration is wound and heated, the coil conductor 16 and the coil conductor 16 are fixed to each other, and the heating coil 13 having a stable shape can be obtained.
[0050]
Note that the heat resistance of the insulating material may be selected from the heat-resistant categories required by design. In this embodiment, the insulator 19 is provided around the coil conductor 16 by extrusion molding. However, a dipping method or the like may be used. In short, the insulator 19 may be provided around the coil conductor 16.
[0051]
If the diameter of the conductor portion of the wire is 0.1 mm or less, the influence of the skin effect in the coil conductor 16 can be reduced, the high frequency resistance of the heating coil 13 can be lowered, and the heat generation of the heating coil 13 is reduced. However, since the cooling performance is improved, this configuration is very effective in the case of the present configuration in which the multi-layer winding is used and the high-frequency resistance is likely to increase.
[0052]
Furthermore, since this configuration can reduce the high-frequency resistance even when the number of turns of the heating coil 13 is increased, it is effective particularly at a high frequency of 40 kHz or more, and it has a low resistance and low permeability such as aluminum and copper. In the case of the heating body 15, it is suitable that the heating frequency is about 40 kHz or more, and it becomes easy to heat a nonmagnetic metal such as aluminum or copper.
[0053]
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.
[0054]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain an induction heating apparatus having high output and improved reliability with respect to the withstand voltage of the heating coil.
[Brief description of the drawings]
Induction in Example 2 of the induced structure cross-sectional view of the cooker configuration sectional view of an induction heating cooker in the first embodiment of the present invention; FIG 3 shows the present invention in reference example 1 of the present invention FIG. 4 is a sectional view of a heating coil in Reference Example 2 of the present invention. FIG. 5A is a diagram showing a case where the sectional shape of the coil conductor in Example 3 of the present invention is circular. ) same, in the fourth embodiment of FIG sectional view of the coil wire in example 4 of the invention; FIG 7 is a cross-sectional view of the wire 8 the invention showing a case where coil conductor cross section is rectangular FIG. 9 is a cross-sectional view of a conventional induction heating cooker. FIG. 10 is a cross-sectional view of a heating coil of the induction heating cooker.
13 Heating coil 16 Coil conductor 17 Inner circumference 18 Outer circumference 19 Insulator

Claims

A heating coil is formed by alternately winding a coil conductor wire with a predetermined diameter in one vertical stage and two vertical stages, and the coil conductor is formed by bundling or twisting strands and forming a cross-sectional circle The assembly line has a shape and an insulator composed of two kinds of resins having different melting points on the outer periphery of the assembly line, and the insulator has a fluorine resin having a low melting point on the outside of the fluorine resin having a high melting point. The heating coil is formed in the middle of the heating coil or after the heating coil is wound, and the insulator and the insulator are heated by melting the insulator and solidifying the insulator. Is an induction heating apparatus configured to inductively heat a low-resistance, low-permeability object to be heated such as aluminum or copper by passing a high-frequency current of 40 kHz or more through the heating coil .

Instead of providing a heating coil formed by alternately winding a coil conductor with a predetermined diameter in a vertical stage and a vertical stage, the coil conductor is alternately switched between a vertical stage and a vertical stage with a predetermined diameter. The induction heating apparatus according to claim 1, further comprising a heating coil formed by repeated winding.