JP4048704B2

JP4048704B2 - Electromagnetic cooker

Info

Publication number: JP4048704B2
Application number: JP2000263315A
Authority: JP
Inventors: 菊夫小宮山
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2000-08-31
Filing date: 2000-08-31
Publication date: 2008-02-20
Anticipated expiration: 2020-08-31
Also published as: JP2002075612A

Description

【０００１】
【発明の属する技術分野】
この発明は電磁調理器の磁界を平準化し、鍋等の被加熱容器の温度分布を改善する技術に関する。
【０００２】
【従来の技術】
図９（ａ）は従来の電磁調理器を示す断面図である。図において、１は略平面渦巻状に巻かれた加熱コイル、２はコイルを配設するコイル台、３は耐熱絶縁材からなる天板、４は天板３に載置され、加熱コイル１により発生する磁場により加熱される被加熱容器である鍋、５は鍋４の発熱により加熱調理される被加熱物、８は天板３から加熱コイル１への熱を遮る断熱材である。図９（ｂ）は鍋４の底面径方向の温度分布を示す温度分布図である。
【０００３】
次に動作について説明する。加熱コイル１への高周波交流電流の通電により形成される磁界の強さは、加熱コイル１の内外径の略中央で最大となり、内周側および外周側に向けて低下する分布を示すことから、この磁界の作用により発熱する鍋４の底面径方向の温度分布も図９（ｂ）のように略Ｍ字状になる。底面全体の温度分布で見ると高温部がドーナツ状に分布し、中心部が低温となるので、被加熱物５は鍋４底面に当たる部分がドーナツ状に焼けるが中心部は生焼けというような調理上の不具合が生じていた。
【０００４】
これに対する改善方法として、実公昭５４−３９７２３号公報の提案がなされている。図１０（ａ）は同公報に記載された高周波誘導加熱装置を示す断面図、（ｂ）はその鍋底温度分布を示す温度分布図である。図１０（ａ）では加熱コイル１に外周多層巻部ｅと内周多層巻部ｆを配設せしめることにより、図１０（ｂ）のように鍋４の底の温度分布は加熱コイル１の外周多層巻部ｅと内周多層巻部ｆに相対する部分の加熱が強められ、多層巻部のない場合の温度分布が破線の分布であるのに対し、実線のように略均一な温度分布が得られるとしている。
【０００５】
【発明が解決しようとする課題】
しかしながら、加熱コイル１の内外径の略中央の最大磁界の部分は、加熱コイルすべての合成磁界であって、この方法の加熱コイル１の外周多層巻部ｅと内周多層巻部ｆもその内外径の略中央の最大磁界の部分の磁界を少なからず強めているため、実際に加熱コイル内周部と外周部の磁界の強さを、加熱コイル内外径の略中央部と略同等にするには、多層巻部にかなり多くのターン数を巻き足す必要があった。
巻き足すターン数が大きく増加すると、コイルの線長が長くなり、電気抵抗が大きく増加するので、コイルを線径を大きくして電気抵抗を元に戻すことも必要になり、コイル部の外径の増大、重量の増大を招くといった課題があった。
【０００６】
この発明は上記のような課題を解決するためになされたもので、コイル部の外径や重量の増大を抑制しつつ、温度分布が良好な電磁調理器を得ることを目的とする。
【０００７】
【課題を解決するための手段】
この発明に係る電磁調理器は、内周側加熱コイルと外周側加熱コイルとが所定距離離れて配設されると共に、前記内周側加熱コイルと複数段巻きになるよう内周側段コイルが配設され、前記外周側加熱コイルと複数段巻きになるよう外周側段コイルが配設され、各コイルには同一の大きさの電流が同時に同方向に流れる加熱コイルと、前記内周側加熱コイルおよび内周側段コイルの内側に段方向にわたって配設された中心部磁性体と、前記加熱コイルの下方に前記内周側加熱コイルから外周側加熱コイルにかけて配設され、内周側の端部が前記中心部磁性体に接触または近接した下面磁性体とを備えたものである。
【０００８】
また、内周側加熱コイルと外周側加熱コイルとの間にスペーサを備えたものである。
【０００９】
また、下面磁性体の内側端部形状を対向する中心部磁性体の外側形状に合わせたものである。
【００１０】
また、内周側加熱コイルと外周側加熱コイルとの間の所定距離を、内周側加熱コイルと外周側加熱コイルとの間隙に対応する鍋底の磁界分布が内周側加熱コイルおよび外周側加熱コイルの各々に対応する鍋底の磁界分布と略均一となるよう設定したものである。
【００１１】
また、加熱コイルを配設するコイル台を備え、内周側加熱コイルおよび外周側加熱コイルが前記コイル台の鍋載置側略同一面上に配設され、内周側段コイルおよび外周側段コイルが前記コイル台の鍋載置側略同一面上と反対側に配設されたものである。
【００１２】
また、内周側段コイルと外周側段コイルとの間にスペーサを備えたものである。
【００１３】
また、内周側段コイル、内周側加熱コイル、外周側加熱コイルおよび外周側段コイルを直列に接続し、両端末をコイル台の一方の側へ引き出したものである。
【００１４】
また、内周側段コイル、内周側加熱コイル、外周側加熱コイルおよび外周側段コイルを直列に接続し、端末を内周側段コイルと外周側段コイルとから引き出したものである。
【００１５】
また、内周側段コイル、内周側加熱コイル、外周側加熱コイルおよび外周側段コイルをコイル台の一方の側へ配設し、前記内周側加熱コイルが前記コイル台とコイル内周側段コイルとの間に位置すると共に前記外周側加熱コイルが前記コイル台と外周側段コイルとの間に位置し、前記内周側段コイルおよび外周側段コイルが略同一面上に配設されたものである。
【００１６】
また、段方向に隣接するコイル順に巻線したものである。
【００１７】
また、端末を内周側段コイルと外周側段コイルとから内周側加熱コイルと外周側加熱コイルとの間を貫通してコイル台の反対側に引き出したものである。
【００１８】
また、内周側段コイルおよび外周側段コイルと同一平面上に下面磁性体を配置したものである。
【００１９】
【発明の実施の形態】
実施の形態１．
以下、この発明の実施の形態を図について説明する。図１（ａ）は本発明の実施の形態１における電磁調理器を示す断面図、図１（ｂ）は図１（ａ）における鍋底の径方向の温度分布を示す温度分布図である。図２（ａ）は図１（ａ）の電磁調理器のうち天板および断熱材を除いた部分の上面図、図２（ｂ）は同下面図である。尚、図２では図面を見やすくするために各加熱コイルの巻線を省略してある。
【００２０】
図において、１ａは渦巻状に巻線された外周側加熱コイル、１ｂは渦巻状に巻線された内周側加熱コイルで、これら外周側加熱コイル１ａおよび内周側加熱コイル１ｂは同一平面上に同心円状に配置されている。１ｃは内周側加熱コイル１ｂの内周寄り下方に設けられた内周側段コイルである２段目内周側加熱コイル、１ｄは外周側加熱コイル１ａの外周寄り下方に設けられた外周側段コイルである２段目外周側加熱コイルで、それぞれ内周側加熱コイル１ｂおよび外周側加熱コイル１ａと同心円状であり、内周側加熱コイル１ｂの内周端と２段目内周側加熱コイル１ｃの内周端とは段方向に略面一となるよう配置され、２段目内周側加熱コイル１ｃの巻数は内周側加熱コイル１ｂの巻数よりも少なく設定されている。また、外周側加熱コイル１ａの外周端と２段目外周側加熱コイル１ｄの外周端とは段方向に略面一となるよう配置され、２段目外周側加熱コイル１ｄの巻数は外周側加熱コイル１ａの巻数よりも少なく設定されている。そして、外周側加熱コイル１ａ、内周側加熱コイル１ｂ、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄで加熱コイル１を構成している。
【００２１】
２は外周側加熱コイル１ａ、内周側加熱コイル１ｂ、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄをそれぞれ所定の位置に配設するコイル台で、外周側加熱コイル１ａおよび内周側加熱コイル１ｂはコイル台２の上面側に、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄはコイル台２の下面側に配設される。コイル台２の上面側は外周側加熱コイル１ａおよび内周側加熱コイル１ｂを収納する部分の間にスペーサとなる凸部２ｃが成形され、その外周側および内周側が段差となり凹形状の収納部２ａ、２ｂが形成されている。同様にコイル台２の下面側は２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄを収納する部分の間にスペーサとなる凸部２ｆが成形され、その内周側および外周側が段差となり凹形状の収納部２ｄ、２ｅが形成されている。３は外周側加熱コイル１ａおよび内周側加熱コイル１ｂの上方に配設され、耐熱絶縁材からなる天板、４は天板３に載置され、加熱コイル１により発生する磁界により加熱される被加熱容器である鍋、５は鍋４の発熱により加熱調理される被加熱物、８は外周側加熱コイル１ａおよび内周側加熱コイル１ｂと天板３との間に設けられ、天板３から加熱コイル１への熱を遮る断熱材である。
【００２２】
９は外周側加熱コイル１ａと内周側加熱コイル１ｂとの間に所定距離の間隙部として確保されるコイル無し部、１９は２段目内周側加熱コイル１ｃと２段目外周側加熱コイル１ｄとの間に所定距離を確保するコイル無し部で、それぞれコイル台２の凸部２ｃ、２ｆで確保している。１０は外周側加熱コイル１ａの内周寄り巻線と内周側加熱コイル１ｂの外周寄り巻線とを結ぶ渡り線、２０は２段目内周側加熱コイル１ｃの外周寄り巻線と２段目外周側加熱コイル１ｄの内周寄り巻線とを結ぶ渡り線で、図３（ｂ）に示すように凸部２ｃ、２ｆに形成されたガイド溝に収納される。１１は内周側加熱コイル１ｂの内周寄り巻線と２段目内周側加熱コイル１ｃの内周寄り巻線とを結ぶ渡り線で、図示されないコイル台２の穴を通り結ばれている。外周側加熱コイル１ａ、内周側加熱コイル１ｂ、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄは電気的に直列接続され、コイル中心軸に対し同一周方向に同じ大きさの電流が流れるように巻線が巻かれている。
【００２３】
加熱コイル１の巻き方向は、例えば図２（ａ）において、外周側加熱コイル１ａが外側から内側に向かって反時計方向に巻かれ、渡り線１０で内周側加熱コイル１ｂの外側に渡り、内側に向かって反時計方向に巻かれ、渡り線１１でコイル台２下面側の２段目内周側加熱コイル１ｃの内側に渡り、図２（ｂ）で２段目内周側加熱コイル１ｃが内側から外側に向かって時計方向に巻かれ、渡り線２０で２段目外周側加熱コイル１ｄの内側に渡り、外側に向かって時計方向に巻かれる。
尚、図面が複雑になるので省略しているが、コイル台２には材料の量を減らし、外周側加熱コイル１ａ、内周側加熱コイル１ｂの熱を逃がすための穴が形成されている。
【００２４】
６はコイル台２上面側に配設された内周側加熱コイル１ｂ内周端および同下面側に配設された２段目内周側加熱コイル１ｃ内周端と対向する位置に段方向にわたって設けられた筒状フェライト製の中心部磁性体で、上部が断熱材８と当接し、内周側加熱コイル１ｂおよび２段目内周側加熱コイル１ｃと同心円状に配置される。７はコイル台２下方に、内周側加熱コイル１ｂ内周側から外周側加熱コイル１ａ外周側に向かい放射状に複数設けられたフェライト製のコイル台下面磁性体で、内側端部が対向する中心部磁性体６の外側形状に合致するよう形成されて中心部磁性体６に当接または近接し、外側端部が２段目外周側加熱コイル１ｄの外側端部よりも外側となるコイル台２の外側の段差部まで達するよう略長方形板状部材を９０度毎に合計４個配置している。
【００２５】
次に動作について説明する。図示されないインバータ電源により各加熱コイル１ａ、１ｂ、１ｃ、１ｄに高周波交流電流で通電すると交番磁界が発生し、磁力線は鍋４の底面に入り、底面中心部から中心部磁性体６、コイル台下面磁性体７を通り、外周側加熱コイル１ａの外側を回って再び鍋４の底面の外側に入り完結する磁路を形成する。
【００２６】
ここで、
（１）内周側加熱コイル１ｂと重ねて２段目内周側加熱コイル１ｃを巻いたことで、従来のドーナツ状の温度分布における中心低温部の磁界を強め、中心部の温度を上昇させる。
（２）外周側加熱コイル１ａと重ねて２段目外周側加熱コイル１ｄを巻いたことで、従来のドーナツ状の温度分布における外周低温部の磁界を強め、外周部の温度を上昇させる。
（３）外周側加熱コイル１ａと内周側加熱コイル１ｂ並びに２段目内周側加熱コイル１ｃと２段目外周側加熱コイル１ｄとの間を適宜に間隙を設けたコイル無し部９および１９とすることで、従来のドーナツ状の温度分布における高温部の温度を低下させる。
【００２７】
（４）中心部磁性体６を設けることで、従来は鍋４の底面の中心部で両側の内周側加熱コイル１ｂから受ける磁界の方向が互いに逆方向で打ち消し合っていたのが、中心の手前で磁力線が曲がって中心部磁性体６を通りコイル台２の下面方向に行くので、鍋４の底面の中心部における磁力線が発熱に有効に作用して、中心部温度を上昇させる。
【００２８】
（５）コイル台２下面に、内周側加熱コイル１ｂ内側から外周側加熱コイル１ａ外側に向かいコイル台下面磁性体７を設けることで、磁界を外周側へ導くので、鍋４の底面の中心部における磁力線が発熱に有効に作用して、中心部温度を上昇させる。
尚、コイル台下面磁性体７を放射状に複数設けることで、円盤状にする場合に比べて等価的に必要な磁路が確保でき、軽量、安価、磁性体の割れ欠け防止が図れる。
【００２９】
（６）中心部磁性体６とコイル台下面磁性体７を接触または近接させることで、中心部磁性体６を通る磁力線を有効にコイル台下面磁性体７を通して鍋４の底面の外側に導くことができ、鍋４の底面の中心部における磁力線の打ち消し合いを防止して、中心部温度を上昇させる。
【００３０】
その結果、図１（ｂ）の鍋温度分布のように略均一な温度分布が実現できた。このような温度分布の平準化は上記６項目の構成要件の相乗効果により得られたものである。以下この点について説明する。
まず、２段目内周側加熱コイル１ｃが無い場合は、鍋４底中心部の磁界は、内周側加熱コイル１ｂによる磁界だけになり、これは従来からのドーナツ状の温度分布の中心部が低温で不都合があった状態と近い。
また、２段目外周側加熱コイル１ｄが無い場合は、鍋４底外周部の磁界は、外周側加熱コイル１ａによる磁界だけになり、中心に比べて温度が低い。
【００３１】
外周側加熱コイル１ａと内周側加熱コイル１ｂとの間のコイル無し部９が確保されていない場合、内外加熱コイルは連続して配設され、前述した図１０の従来例の構造となり、ドーナツ状温度分布の高温部の磁界に対抗するだけ、中心部の磁界を強めるためには、２段目内周側加熱コイル１ｃを多段に多数巻く必要がある。巻き足すターン数が大きく増加すると、コイルの線長が長くなり、電気抵抗が大きく増加するので、コイルの線径を大きくして電気抵抗を元に戻すことも必要になり、コイル部の外径の増大、重量の増大を招く。コイル無し部９を設けることによって、コイルのターン数を増やすことなく加熱範囲を拡大し、かつ加熱効率を低減させることなく、ドーナツ状の高温部の温度を低減することが可能になる。
【００３２】
中心部磁性体６が無い場合は、前述したように鍋４底中心部の磁界が打ち消し合って弱まるため、内周側に２段目内周側加熱コイル１ｃを設けても、鍋４底中心部の磁界は増加しない。
コイル台下面磁性体７が無い場合も、中心部磁性体６を通る磁界を有効に外周側に導くことができず、鍋４底中心部の磁界が打ち消し合って弱まるため、内周側に２段目内周側加熱コイル１ｃを設けても、鍋４底中心部の磁界は増加しない。
【００３３】
中心部磁性体６とコイル台下面磁性体７の間が離れすぎている場合も、そこで磁気抵抗が大きくなり、中心部磁性体６を通る磁界を有効に外周側に導くことができず、鍋４底中心部の磁界が打ち消し合って弱まるため、内周側に２段目内周側加熱コイル１ｃを設けても、鍋４底中心部の磁界は増加しない。
【００３４】
このように、上記６項目の構成要件の相乗効果によりコイル部の外径や重量の増大を抑制しつつ、略均一な温度分布が実現できる。
ここで、コイル無し部９、１９による外周側加熱コイル１ａと内周側加熱コイル１ｂ並びに２段目外周側加熱コイル１ｄと２段目内周側加熱コイル１ｃとの間の所定距離は、底の厚さが略同一で底の組成材料が同一であり、且つ鍋底が外周側加熱コイル１ａの外周側まで達する鍋４を載置したとき、コイル無し部９、１９に対応する鍋４底の磁界分布が外周側加熱コイル１ａ、内周側加熱コイル１ｂ、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄの各々に対応する鍋４底の磁界分布と略均一になるよう設定されている。
【００３５】
このように、外周側加熱コイル１ａと内周側加熱コイル１ｂとの間に確保されるコイル無し部分９の所定距離並びに２段目外周側加熱コイル１ｄと２段目内周側加熱コイル１ｃとの間に確保されるコイル無し部分１９の所定距離は、上記６項目の構成要件の兼ね合いで相乗効果が顕著に得られる値に設定され、中心部の磁界を効率的に強め、外周側の合成磁界への影響を小さくしている。そしてこのような構成によって、コイル線径の増大や、コイル線長の増大を抑えつつ、温度分布を平準化することが可能になる。
【００３６】
図３は図１および図２のコイル台２部分を示す拡大図で、図において１２は２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄとコイル台下面磁性体７とを絶縁する絶縁シートである。内周側加熱コイル１ｂと２段目内周側加熱コイル１ｃとの絶縁は、コイル台２によってなされている。
図３の構造の場合、図２で渡り線１１の通るコイル台２の穴から２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄの必要長さだけ先に通し、２段目内周側加熱コイル１ｃは渡り線１１の所から必要な巻数だけ外側に向かって渦巻状に巻き、渡り線２０で２段目外周側加熱コイル１ｄに渡り、必要な巻数だけ外側に向かって渦巻状に巻く。内周側加熱コイル１ｂは渡り線１１の所から必要な巻数だけ外側に向かって渦巻状に巻き、渡り線１０で外周側加熱コイル１ａに渡り、必要な巻数だけ外側に向かって渦巻状に巻く。このようにして加熱コイル１ａ、１ｂ、１ｃ、１ｄの直列巻きができる。
【００３７】
この構造の場合、２段目内周側加熱コイル１ｃが内周側加熱コイル１ｂの裏側に、２段目外周側加熱コイル１ｄが外周側加熱コイル１ａの裏側にそれぞれ配設されるので、コイル台２の両面に各々１段のコイルを巻けばよい。また、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄがコイル台２の下面になるので、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄの放熱が良い、という効果がある。また、コイル台下面磁性体７が２段目外周側加熱コイル１ｄを下から支えているので、コイルが崩れる心配がなく、磁界も外側へ良好に導かれる。
【００３８】
実施の形態２．
図４は、図３の他の実施の形態を示す拡大断面図である。本実施の形態ではコイル巻線の仕方が実施の形態１と異なる。図４において、図２と同様な位置に穿設された渡り線１１の通るコイル台２の穴から２段目内周側加熱コイル１ｃの必要長さだけ先に通し、２段目内周側加熱コイル１ｃは渡り線１１の所から必要な巻数だけ外側に向かって渦巻状に巻き、下方に引き出す。内周側加熱コイル１ｂは渡り線１１の所から必要な巻数だけ外側に向かって渦巻状に巻き、渡り線１０で外周側加熱コイル１ａに渡り、必要な巻数だけ外側に向かって渦巻状に巻く。外側にてコイル台２に穿設された穴に渡り線を通して２段目外周側加熱コイル１ｄ外側に渡り、２段目外周側加熱コイル１ｄを必要な巻数だけ内側に向かって渦巻状に巻いて下方に引き出す。このようにして加熱コイル１ａ、１ｂ、１ｃ、１ｄの直列巻きができる。
【００３９】
この構造の場合、２段目内周側加熱コイル１ｃと２段目外周側加熱コイル１ｄとがコイル台２の別々の穴を通したコイルを巻きまわすことで形成されるので、コイル台２の各穴を通す線長が短くて済み、製作性が向上する。また、２段目内周側加熱コイル１ｃが内周側加熱コイル１ｂの裏側に、２段目外周側加熱コイル１ｄが外周側加熱コイル１ａの裏側にそれぞれ配設されるので、コイル台２の両面に各々１段のコイルを巻けばよい。また、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄがコイル台２の下面になるので、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄの放熱が良い、という効果がある。また、コイル台下面磁性体７が２段目外周側加熱コイル１ｄを下から支えているので、コイルが崩れる心配がなく、磁界も外側へ良好に導かれる。
【００４０】
実施の形態３．
図５は、図３の他の実施の形態を示す拡大断面図である。図において、内周側加熱コイル１ｂおよび２段目内周側加熱コイル１ｃ並びに外周側加熱コイル１ａおよび２段目外周側加熱コイル１ｄはコイル台２の上面側（鍋４側）に配設されている。２ａはコイル台２の上面外側に形成され、外周側加熱コイル１ａを収納する凹部、２ｂはコイル台２の上面内側に形成され、内周側加熱コイル１ｂを収納する凹部、１３は内周側加熱コイル１ｂと２段目内周側加熱コイル１ｃとを絶縁する絶縁シートである。凹部２ａ、２ｂに収納された内周側加熱コイル１ｂ、外周側加熱コイル１ａの上端面とこれら内周側加熱コイル１ｂおよび外周側加熱コイル１ａ間のコイル無し部９を確保するためのコイル台２の凸部２ｃの上端面とは略同じ高さであり、絶縁シート１３によって略平らな面が形成され、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄは絶縁シート１３上の同一平面上に位置することができる。その他の構成は実施の形態１と同様であり、説明を省略する。
【００４１】
図５の構造の場合、内周側加熱コイル１ｂおよび外周側加熱コイル１ａとコイル台下面磁性体７との絶縁は、間に介在するコイル台２によってなされる。また、巻線工程としては、２段目内周側加熱コイル１ｃおよび２段目外周側加熱コイル１ｄの分の線長を余らせておいて、内周側加熱コイル１ｂを最初に内側から必要な巻数だけ外側に向かって渦巻状に巻き、渡り線１０で外周側加熱コイル１ａに渡り、必要な巻数だけ外側に向かって渦巻状に巻く。尚、渡り線１０が通る部分の凸部２ｃにはガイドとなる溝が形成されている。
【００４２】
次に絶縁シート１３を載せて、図示されない絶縁シート１３の内側切欠き部を通し、２段目内周側加熱コイル１ｃの内側から必要な巻数だけ外側に向かって渦巻状に巻き、渡り線２０で２段目外周側加熱コイル１ｄに渡り、２段目外周側加熱コイル１ｄの内側から必要な巻数だけ外側に向かって渦巻状に巻くと、各加熱コイル１ａ、１ｂ、１ｃ、１ｄの直列巻きができる。
本実施の形態における構造の場合、巻線作業はコイル台２の片面（上面側）で実施できるから、巻線作業の作業性が良いという効果がある。
【００４３】
実施の形態４．
図６は図５の他の実施の形態を示す拡大断面図である。図において、コイル台２の片面（上面側）に内周側加熱コイル１ｂ、２段目内周側加熱コイル１ｃ、外周側加熱コイル１ａおよび２段目外周側加熱コイル１ｄが配設される点では実施の形態３と同様である。本実施の形態では、図のコイル断面に付した数字が巻順となるように巻線する。即ち、内側から交互に内周側加熱コイル１ｂ、２段目内周側加熱コイル１ｃの巻線となるように外側へと巻きはじめ、２段目内周側加熱コイル１ｃよりも巻数の多い内周側加熱コイル１ｂを外側まで巻いたところで、渡り線１０で外周側加熱コイル１ａの内側へ渡す。
【００４４】
次いで外周側加熱コイル１ａを内側から外側へ向かって巻いていき、２段目外周側加熱コイル１ｄとの重なり部分まで来たら内側から交互に外周側加熱コイル１ａ、２段目外周側加熱コイル１ｄの巻線となるように外側へと巻いていく。こうして任意のコイルに対し、巻線順の近いコイルが隣接するようになる。
このような巻き方により、隣接するコイルの巻線順が近くなることから、隣接するコイル同士の電位差が比較的小さくなり、内周側加熱コイル１ｂと２段目内周側加熱コイル１ｃとの間や外周側加熱コイル１ａと２段目外周側加熱コイル１ｄとの間の絶縁シートを不要にできる。
【００４５】
実施の形態５．
図７は図５の他の実施の形態を示す拡大断面図である。図において、コイル台２の片面（上面側）に内周側加熱コイル１ｂ、２段目内周側加熱コイル１ｃ、外周側加熱コイル１ａおよび２段目外周側加熱コイル１ｄが配設される点では実施の形態３と同様である。本実施の形態では、先ず２段目内周側加熱コイル１ｃ分の線長を余らせておき、内周側加熱コイル１ｂを内側から外側へと巻き、外側から渡り線１０により外周側加熱コイル１ａの内側へ渡し、外周側加熱コイル１ａを内側から外側へと巻く。その後内周側加熱コイル１ｂおよび外周側加熱コイル１ａの上に絶縁シートを載せ、外周側加熱コイル１ａの外周側から上方へ渡す。
【００４６】
次いで２段目外周側加熱コイル１ｄを必要な巻数だけ外側から内側へと巻いていき、内側まできたら、内周側加熱コイル１ｂと外周側加熱コイル１ａとの間のコイル無し部９から図示しないコイル台２に穿設した穴を貫通させてコイル台２の反対側（下面側）へと引き出す。
内周側については、内周側加熱コイル１ｂの内周側から上方へ渡し、２段目内周側加熱コイル１ｃを必要な巻数だけ内側から外側へと巻いていき、外側まできたら、内周側加熱コイル１ｂと外周側加熱コイル１ａとの間のコイル無し部９から図示しないコイル台２に穿設した穴を貫通させてコイル台２の反対側（下面側）へと引き出す。
【００４７】
このような巻き方により、コイル台２の上面側だけで巻線作業ができ、作業性が向上する。また、コイルをコイル無し部９からコイル台２の反対側（下面側）へと引き出すから、コイル台の外側へ引き出し線を引き出さなくてもよく、平面方向に小さくできる。また、２本の引き出し線は互いにコイル無し部９に集約できるから、配線が容易になる。
【００４８】
実施の形態６．
図８は、図４の他の実施の形態を示す拡大断面図である。図において、２ｆはコイル台２の下面側に設けられ、２段目内周側加熱コイル１ｃの外周側の広がりまたは２段目外周側加熱コイル１ｄの内周側への広がりを規制する凸部で、凸部２ｆ間のコイル台２下面側は切り欠かれている。７ａは２段目内周側加熱コイル１ｃおよび凸部２ｆの下方に設けられたフェライト製のコイル台下面磁性体、７ｂは凸部２ｆ同士の切り欠き部分であって、コイル無し部１９に相当する部分に設けられたコイル台下面磁性体、７ｃは２段目外周側加熱コイル１ｄおよび凸部２ｆの下方に設けられたフェライト製のコイル台下面磁性体であり、これらコイル台下面磁性体７ａ、７ｂ、７ｃは径方向に若干の重なりをもって配設されている。２段目内周側加熱コイル１ｃ、２段目外周側加熱コイル１ｄおよびコイル台下面磁性体７ｂは同一平面上に位置する。その他の構成は実施の形態１と同様であり、その説明を省略する。
【００４９】
このような構成とすることにより、コイル台下面磁性体７ａは２段目内周側加熱コイル１ｃの下側にて中心部磁性体６と、外周寄りにてコイル台下面磁性体７ｂと磁路を有効に接続し、同様にコイル台下面磁性体７ｃは２段目外周側加熱コイル１ｄの下側内周寄りにてコイル台下面磁性体７ｂと磁路を有効に接続する。
そして、２段目内周側加熱コイル１ｃ外周寄りから２段目外周側加熱コイル１ｄまでのコイル台２裏側に近接してコイル台下面磁性体７ｂを配設したので、鍋との磁気結合が強まり、加熱効率が向上するという効果がある。
尚、図５〜７の構造において、コイル台下面磁性体７ｂを外周側加熱コイル１ａと内周側加熱コイル１ｂとの間に略面一に配置しても良い。
【００５０】
【発明の効果】
以上のように、この発明によれば、内周側加熱コイルと外周側加熱コイルとが所定距離離れて配設されると共に、前記内周側加熱コイルと複数段巻きになるよう内周側段コイルが配設され、前記外周側加熱コイルと複数段巻きになるよう外周側段コイルが配設され、各コイルには同一の大きさの電流が同時に同方向に流れる加熱コイルと、前記内周側加熱コイルおよび内周側段コイルの内側に段方向にわたって配設された中心部磁性体と、前記加熱コイルの下方に前記内周側加熱コイルから外周側加熱コイルにかけて配設され、内周側の端部が前記中心部磁性体に接触または近接した下面磁性体とを備えたので、コイル部の外径や重量の増大を抑制しつつ、温度分布の良好な電磁調理器にできる効果が得られる。
【００５１】
また、内周側加熱コイルと外周側加熱コイルとの間にスペーサを備えたので、加熱コイルが精度良く位置決めできる効果が得られる。
【００５２】
また、下面磁性体の内側端部形状を対向する中心部磁性体の外側形状に合わせたので、中心部の磁界が通り易くなり、加熱効率が向上する効果が得られる。
【００５３】
また、内周側加熱コイルと外周側加熱コイルとの間の所定距離を、内周側加熱コイルと外周側加熱コイルとの間隙に対応する鍋底の磁界分布が内周側加熱コイルおよび外周側加熱コイルの各々に対応する鍋底の磁界分布と略均一となるよう設定したので、コイル部の外径や重量の増大を抑制しつつ、温度分布の良好な電磁調理器にできる効果が得られる。
【００５４】
また、加熱コイルを配設するコイル台を備え、内周側加熱コイルおよび外周側加熱コイルが前記コイル台の鍋載置側略同一面上に配設され、内周側段コイルおよび外周側段コイルが前記コイル台の鍋載置側略同一面上と反対側に配設されたので、コイル台により内周側加熱コイルおよび外周側加熱コイルと段コイルとの絶縁が容易に行える効果が得られる。
【００５５】
また、内周側段コイルと外周側段コイルとの間にスペーサを備えたので、段コイルが精度良く位置決めできる効果が得られる。
【００５６】
また、内周側段コイル、内周側加熱コイル、外周側加熱コイルおよび外周側段コイルを直列に接続し、両端末をコイル台の一方の側へ引き出したので、コイル端末が集約されるから製作性が向上するとともに、装置を小型化できる効果が得られる。
【００５７】
また、内周側段コイル、内周側加熱コイル、外周側加熱コイルおよび外周側段コイルを直列に接続し、端末を内周側段コイルと外周側段コイルとから引き出したので、コイル台を貫通する線長が短くて済み、製作性が向上する効果が得られる。
【００５８】
また、内周側段コイル、内周側加熱コイル、外周側加熱コイルおよび外周側段コイルをコイル台の一方の側へ配設し、前記内周側加熱コイルが前記コイル台とコイル内周側段コイルとの間に位置すると共に前記外周側加熱コイルが前記コイル台と外周側段コイルとの間に位置し、前記内周側段コイルおよび外周側段コイルが略同一面上に配設されたので、巻線の作業性が向上する効果が得られる。
【００５９】
また、段方向に隣接するコイル順に巻線したので、隣接するコイル間の電位差を小さくできる効果が得られる。
【００６０】
また、端末を内周側段コイルと外周側段コイルとから内周側加熱コイルと外周側加熱コイルとの間を貫通してコイル台の反対側に引き出したので、巻線の作業性が向上するとともにコイル端末が集約されるから製作性が向上し、さらに装置を小型化できる効果が得られる。
【００６１】
また、内周側段コイルおよび外周側段コイルと同一平面上に下面磁性体を配置したので、磁気結合が強まり、加熱効率が向上する効果が得られる。
【図面の簡単な説明】
【図１】（ａ）この発明の実施の形態１における電磁調理器を示す断面図である。
（ｂ）図１（ａ）における鍋底の径方向の温度分布を示す温度分布図である。
【図２】（ａ）図１（ａ）の電磁調理器のうち天板および断熱材を除いた部分の上面図である。
（ｂ）図１（ａ）の電磁調理器の下面図である。
【図３】図１および図２におけるコイル台部分を示す拡大断面図である。
【図４】この発明の実施の形態２における電磁調理器を示す拡大断面図である。
【図５】この発明の実施の形態３における電磁調理器を示す拡大断面図である。
【図６】この発明の実施の形態４における電磁調理器を示す拡大断面図である。
【図７】この発明の実施の形態５における電磁調理器を示す拡大断面図である。
【図８】この発明の実施の形態６における電磁調理器を示す部分平面図である。
【図９】（ａ）従来の電磁調理器を示す断面図である。
（ｂ）図９（ａ）における鍋底の径方向の温度分布を示す温度分布図である。
【図１０】（ａ）他の従来の電磁調理器を示す断面図である。
（ｂ）図１０（ａ）における鍋底の径方向の温度分布を示す温度分布図である。
【符号の説明】
１加熱コイル、１ａ外周側加熱コイル、１ｂ内周側加熱コイル、１ｃ内周側２段目加熱コイル、１ｄ外周側２段目加熱コイル、２コイル台、２ａ、２ｂ、２ｄ、２ｅ収納部、２ｃ、２ｆ凸部、３天板、４鍋、５被加熱物、６中心部磁性体、７コイル台下面磁性体、８断熱材、９、１９コイル無し部、１０、１１、２０渡り線、１２、１３絶縁シート。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for leveling the magnetic field of an electromagnetic cooker and improving the temperature distribution of a heated container such as a pan.
[0002]
[Prior art]
Fig.9 (a) is sectional drawing which shows the conventional electromagnetic cooker. In the figure, 1 is a heating coil wound in a substantially plane spiral shape, 2 is a coil base on which the coil is disposed, 3 is a top plate made of a heat-resistant insulating material, 4 is placed on the top plate 3, and is heated by the heating coil 1. A pan, which is a heated container heated by a generated magnetic field, 5 is an object to be heated and cooked by the heat generated by the pan 4, and 8 is a heat insulating material that blocks heat from the top plate 3 to the heating coil 1. FIG. 9B is a temperature distribution diagram showing a temperature distribution in the bottom diameter direction of the pan 4.
[0003]
Next, the operation will be described. The strength of the magnetic field formed by energizing the heating coil 1 with the high-frequency alternating current is maximized at the approximate center of the inner and outer diameters of the heating coil 1 and shows a distribution that decreases toward the inner and outer peripheral sides. The temperature distribution in the radial direction of the bottom surface of the pan 4 that generates heat by the action of the magnetic field is also substantially M-shaped as shown in FIG. When looking at the temperature distribution of the entire bottom surface, the hot part is distributed in a donut shape, and the center part is low in temperature. The problem occurred.
[0004]
As an improvement method for this, Japanese Utility Model Publication No. 54-39723 has been proposed. FIG. 10A is a cross-sectional view showing the high-frequency induction heating device described in the publication, and FIG. 10B is a temperature distribution diagram showing the pan bottom temperature distribution. In FIG. 10A, the temperature distribution at the bottom of the pan 4 is the outer periphery of the heating coil 1 as shown in FIG. 10B by arranging the outer peripheral multilayer winding portion e and the inner peripheral multilayer winding portion f on the heating coil 1. The heating of the portion facing the multilayer winding portion e and the inner circumferential multilayer winding portion f is intensified, and the temperature distribution in the absence of the multilayer winding portion is the distribution of the broken line, whereas the substantially uniform temperature distribution as shown by the solid line is It is supposed to be obtained.
[0005]
[Problems to be solved by the invention]
However, the portion of the maximum magnetic field at the approximate center of the inner and outer diameters of the heating coil 1 is the combined magnetic field of all the heating coils, and the outer peripheral multilayer winding portion e and the inner peripheral multilayer winding portion f of the heating coil 1 of this method also Since the magnetic field of the maximum magnetic field portion at the approximate center of the diameter is strengthened to some extent, the magnetic field strength of the inner and outer peripheral portions of the heating coil is actually made approximately the same as the approximately central portion of the inner and outer diameters of the heating coil. Needed to add a large number of turns to the multi-layer winding.
If the number of turns to be added increases greatly, the wire length of the coil increases and the electrical resistance increases greatly. Therefore, it is also necessary to increase the wire diameter of the coil and restore the electrical resistance, and the outer diameter of the coil section There is a problem of increasing the weight and weight.
[0006]
The present invention has been made to solve the above-described problems, and an object thereof is to obtain an electromagnetic cooker having a good temperature distribution while suppressing an increase in the outer diameter and weight of the coil portion.
[0007]
[Means for Solving the Problems]
In the electromagnetic cooker according to the present invention, the inner peripheral side heating coil and the outer peripheral side heating coil are arranged apart from each other by a predetermined distance, and the inner peripheral side step coil is arranged in a plurality of stages with the inner peripheral side heating coil. An outer peripheral side coil is disposed so as to be wound in a plurality of stages with the outer peripheral side heating coil, a heating coil in which the same current flows in the same direction simultaneously in each coil, and the inner peripheral side heating A central magnetic body disposed in a step direction inside the coil and the inner peripheral side step coil, and an inner peripheral end disposed below the heating coil from the inner peripheral side heating coil to the outer peripheral side heating coil. And a bottom magnetic body in contact with or close to the central magnetic body.
[0008]
Further, a spacer is provided between the inner peripheral side heating coil and the outer peripheral side heating coil.
[0009]
Further, the inner end shape of the lower magnetic body is matched with the outer shape of the opposing central magnetic body.
[0010]
In addition, a predetermined distance between the inner peripheral heating coil and the outer peripheral heating coil is set so that the magnetic field distribution on the pan bottom corresponding to the gap between the inner peripheral heating coil and the outer peripheral heating coil is equal to the inner peripheral heating coil and outer peripheral heating. It is set so as to be substantially uniform with the magnetic field distribution of the pan bottom corresponding to each of the coils.
[0011]
In addition, a coil base for arranging the heating coil is provided, and the inner peripheral side heating coil and the outer peripheral side heating coil are arranged on substantially the same surface on the pan mounting side of the coil base, and the inner peripheral side step coil and the outer peripheral side step The coil is disposed on the same side as the pan mounting side of the coil base.
[0012]
Further, a spacer is provided between the inner peripheral side step coil and the outer peripheral side step coil.
[0013]
Further, the inner peripheral side step coil, the inner peripheral side heating coil, the outer peripheral side heating coil, and the outer peripheral side step coil are connected in series, and both terminals are drawn out to one side of the coil base.
[0014]
Further, the inner peripheral side step coil, the inner peripheral side heating coil, the outer peripheral side heating coil and the outer peripheral side step coil are connected in series, and the terminal is drawn out from the inner peripheral side step coil and the outer peripheral side step coil.
[0015]
Also, an inner peripheral side step coil, an inner peripheral side heating coil, an outer peripheral side heating coil, and an outer peripheral side step coil are arranged on one side of the coil base, and the inner peripheral side heating coil is connected to the coil base and the coil inner peripheral side. The outer peripheral heating coil is positioned between the coil base and the outer peripheral step coil, and the inner peripheral step coil and the outer peripheral step coil are disposed on substantially the same plane. It is a thing.
[0016]
Further, the coils are wound in the order of coils adjacent in the step direction.
[0017]
Further, the terminal is pulled out from the inner peripheral side step coil and the outer peripheral side step coil through the inner peripheral side heating coil and the outer peripheral side heating coil to the opposite side of the coil base.
[0018]
Further, the lower surface magnetic body is disposed on the same plane as the inner peripheral side step coil and the outer peripheral side step coil.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiments of the present invention will be described below with reference to the drawings. Fig.1 (a) is sectional drawing which shows the electromagnetic cooker in Embodiment 1 of this invention, FIG.1 (b) is a temperature distribution figure which shows temperature distribution of the radial direction of the pan bottom in Fig.1 (a). Fig.2 (a) is a top view of the part except the top plate and a heat insulating material among the electromagnetic cookers of Fig.1 (a), FIG.2 (b) is the bottom view. In FIG. 2, the windings of the heating coils are omitted in order to make the drawing easier to see.
[0020]
In the figure, 1a is an outer peripheral side heating coil wound in a spiral shape, 1b is an inner peripheral side heating coil wound in a spiral shape, and these outer peripheral side heating coil 1a and inner peripheral side heating coil 1b are on the same plane. Are arranged concentrically. 1c is a second-stage inner periphery side heating coil that is an inner periphery side step coil provided below the inner periphery side of the inner periphery side heating coil 1b, and 1d is an outer periphery side provided below the outer periphery side of the outer periphery side heating coil 1a. A second-stage outer peripheral heating coil, which is a step coil, is concentric with the inner peripheral heating coil 1b and the outer peripheral heating coil 1a, respectively, and the inner peripheral end of the inner peripheral heating coil 1b and the second inner peripheral heating The coil 1c is arranged so as to be substantially flush with the inner peripheral end of the coil 1c, and the number of turns of the second-stage inner peripheral heating coil 1c is set to be smaller than the number of turns of the inner peripheral heating coil 1b. Further, the outer peripheral end of the outer peripheral heating coil 1a and the outer peripheral end of the second outer peripheral heating coil 1d are arranged to be substantially flush with each other in the step direction, and the number of turns of the second outer peripheral heating coil 1d is the outer peripheral heating. It is set to be smaller than the number of turns of the coil 1a. And the outer periphery side heating coil 1a, the inner periphery side heating coil 1b, the 2nd step | paragraph inner periphery side heating coil 1c, and the 2nd step | paragraph outer periphery side heating coil 1d comprise the heating coil 1. FIG.
[0021]
Reference numeral 2 denotes a coil base in which the outer peripheral side heating coil 1a, the inner peripheral side heating coil 1b, the second stage inner peripheral side heating coil 1c, and the second stage outer peripheral side heating coil 1d are arranged at predetermined positions, respectively. 1 a and the inner peripheral side heating coil 1 b are disposed on the upper surface side of the coil base 2, and the second stage inner peripheral side heating coil 1 c and the second stage outer peripheral side heating coil 1 d are disposed on the lower surface side of the coil base 2. On the upper surface side of the coil base 2, a convex portion 2 c serving as a spacer is formed between the portions for housing the outer peripheral side heating coil 1 a and the inner peripheral side heating coil 1 b, and the outer peripheral side and the inner peripheral side become a step to form a concave storage portion. 2a and 2b are formed. Similarly, on the lower surface side of the coil base 2, convex portions 2 f serving as spacers are formed between the portions accommodating the second-stage inner periphery side heating coil 1 c and the second-stage outer periphery side heating coil 1 d, and the inner periphery side and the outer periphery thereof are formed. Concave portions 2d and 2e are formed with steps on the sides. 3 is disposed above the outer peripheral side heating coil 1a and the inner peripheral side heating coil 1b, and the top plate 4 made of a heat-resistant insulating material is placed on the top plate 3 and heated by the magnetic field generated by the heating coil 1. A pan, which is a heated container, 5 is an object to be cooked by the heat generated by the pan 4, and 8 is provided between the outer peripheral heating coil 1 a and the inner peripheral heating coil 1 b and the top plate 3. It is a heat insulating material that blocks heat from the heating coil 1.
[0022]
9 is a non-coiled portion secured as a gap of a predetermined distance between the outer peripheral heating coil 1a and the inner peripheral heating coil 1b, and 19 is a second-stage inner peripheral heating coil 1c and a second-stage outer peripheral heating coil. The coil-less portion that secures a predetermined distance from 1d is secured by the convex portions 2c and 2f of the coil base 2, respectively. 10 is a connecting wire connecting the inner peripheral winding of the outer peripheral heating coil 1a and the outer peripheral winding of the inner peripheral heating coil 1b, and 20 is the outer peripheral winding of the second inner peripheral heating coil 1c and two stages. As shown in FIG. 3B, the connecting wire connecting the outer peripheral side heating coil 1d to the inner peripheral winding is housed in the guide groove formed in the convex portions 2c and 2f. 11 is a connecting wire that connects the inner peripheral winding of the inner peripheral heating coil 1b and the inner peripheral winding of the second inner peripheral heating coil 1c, and is connected through a hole in the coil base 2 (not shown). . The outer peripheral heating coil 1a, the inner peripheral heating coil 1b, the second inner peripheral heating coil 1c, and the second outer peripheral heating coil 1d are electrically connected in series and have the same size in the same circumferential direction with respect to the coil central axis. The winding is wound so that the current flows.
[0023]
The winding direction of the heating coil 1 is, for example, in FIG. 2A, the outer peripheral heating coil 1a is wound counterclockwise from the outer side to the inner side, and crosses the outer peripheral heating coil 1b with the connecting wire 10. It is wound inward in the counterclockwise direction, crosses over the inner side of the second stage inner peripheral side heating coil 1c on the lower surface side of the coil base 2 by the crossover wire 11, and in the second stage inner peripheral side heating coil 1c in FIG. Is wound clockwise from the inner side to the outer side, crosses the inner side of the second stage outer peripheral side heating coil 1d by the connecting wire 20, and is wound clockwise toward the outer side.
Although not shown because the drawing is complicated, the coil base 2 is formed with holes for reducing the amount of material and releasing the heat from the outer peripheral heating coil 1a and the inner peripheral heating coil 1b.
[0024]
Reference numeral 6 denotes an inner peripheral end of the inner peripheral heating coil 1b disposed on the upper surface side of the coil base 2 and a position facing the inner peripheral end of the second inner peripheral heating coil 1c disposed on the lower surface side in the step direction. The central magnetic body made of cylindrical ferrite is provided, the upper part is in contact with the heat insulating material 8, and is arranged concentrically with the inner peripheral heating coil 1b and the second inner peripheral heating coil 1c. Reference numeral 7 denotes a ferrite coil base lower surface magnetic body that is radially provided from the inner peripheral side of the inner peripheral heating coil 1b to the outer peripheral side of the outer peripheral heating coil 1a below the coil base 2, with the inner end facing the center. The coil base 2 is formed so as to match the outer shape of the partial magnetic body 6, is in contact with or close to the central magnetic body 6, and the outer end portion is outside the outer end portion of the second-stage outer peripheral heating coil 1 d. A total of four substantially rectangular plate-like members are arranged every 90 degrees so as to reach the stepped portion on the outer side.
[0025]
Next, the operation will be described. When each heating coil 1a, 1b, 1c, 1d is energized with a high-frequency alternating current by an inverter power source (not shown), an alternating magnetic field is generated. A magnetic path is formed that passes through the magnetic body 7, goes around the outside of the outer peripheral heating coil 1 a, enters the outside of the bottom of the pan 4 again, and is completed.
[0026]
here,
(1) The second stage inner circumference side heating coil 1c is wound on the inner circumference side heating coil 1b, thereby strengthening the magnetic field of the central low temperature part in the conventional donut-shaped temperature distribution and increasing the temperature of the center part. .
(2) By winding the outer peripheral side heating coil 1a so as to overlap the outer peripheral side heating coil 1a, the magnetic field of the outer peripheral low temperature part in the conventional donut-shaped temperature distribution is strengthened, and the temperature of the outer peripheral part is increased.
(3) Non-coiled portions 9 and 19 in which an appropriate gap is provided between the outer peripheral side heating coil 1a and the inner peripheral side heating coil 1b and between the second stage inner peripheral side heating coil 1c and the second stage outer peripheral side heating coil 1d. By doing so, the temperature of the high temperature part in the conventional donut-shaped temperature distribution is lowered.
[0027]
(4) By providing the center part magnetic body 6, the direction of the magnetic field received from the inner side heating coil 1b on both sides at the center part of the bottom surface of the pan 4 has been canceled in the opposite direction. Since the magnetic lines of force bend in front and pass through the central magnetic body 6 toward the lower surface of the coil base 2, the magnetic lines of force at the central portion of the bottom surface of the pan 4 effectively act on heat generation and raise the central temperature.
[0028]
(5) Since the magnetic field is guided to the outer peripheral side by providing the coil base lower surface magnetic body 7 from the inner peripheral side heating coil 1b inner side to the outer peripheral side heating coil 1a outer side on the lower surface of the coil base 2, the center of the bottom surface of the pan 4 The magnetic field lines in the section effectively act on heat generation and raise the center temperature.
In addition, by providing a plurality of coil base lower surface magnetic bodies 7 in a radial manner, a magnetic path equivalently equivalent to that in the case of a disk shape can be secured, and light weight, low cost, and prevention of cracking of the magnetic body can be achieved.
[0029]
(6) By bringing the central magnetic body 6 and the coil base lower surface magnetic body 7 into contact or close to each other, the magnetic field lines passing through the central magnetic body 6 are effectively guided to the outside of the bottom surface of the pan 4 through the coil base lower surface magnetic body 7. This prevents the lines of magnetic force from canceling out at the center of the bottom of the pan 4 and increases the center temperature.
[0030]
As a result, a substantially uniform temperature distribution such as the pot temperature distribution in FIG. Such leveling of the temperature distribution is obtained by a synergistic effect of the constituent requirements of the above six items. This point will be described below.
First, when there is no second-stage inner peripheral side heating coil 1c, the magnetic field at the bottom center of the pan 4 is only the magnetic field due to the inner peripheral side heating coil 1b, which is the central part of the conventional donut-shaped temperature distribution. However, it is close to the inconvenient state at low temperatures.
Moreover, when there is no 2nd stage | step outer peripheral side heating coil 1d, the magnetic field of the pan 4 bottom outer peripheral part becomes only the magnetic field by the outer peripheral side heating coil 1a, and temperature is low compared with the center.
[0031]
When the coilless portion 9 between the outer peripheral side heating coil 1a and the inner peripheral side heating coil 1b is not secured, the inner and outer heating coils are continuously arranged, and the structure of the conventional example of FIG. In order to strengthen the magnetic field in the central part only against the magnetic field in the high temperature part of the state temperature distribution, it is necessary to wind many second-stage inner peripheral heating coils 1c in multiple stages. If the number of turns to be added increases greatly, the wire length of the coil increases and the electrical resistance increases greatly. Therefore, it is necessary to increase the wire diameter of the coil and restore the electrical resistance, and the outer diameter of the coil section Increase in weight and weight. By providing the coilless portion 9, it is possible to expand the heating range without increasing the number of turns of the coil and reduce the temperature of the donut-shaped high temperature portion without reducing the heating efficiency.
[0032]
When there is no center part magnetic body 6, the magnetic field at the bottom center of the pan 4 cancels and weakens as described above. Therefore, even if the second-stage inner peripheral heating coil 1c is provided on the inner periphery, the center of the bottom of the pan 4 The magnetic field of the part does not increase.
Even in the absence of the coil base lower surface magnetic body 7, the magnetic field passing through the central magnetic body 6 cannot be effectively guided to the outer peripheral side, and the magnetic field at the bottom central part of the pan 4 cancels and weakens. Even if the stage inner periphery side heating coil 1c is provided, the magnetic field at the bottom center of the pan 4 does not increase.
[0033]
When the center magnetic body 6 and the coil base lower surface magnetic body 7 are too far apart, the magnetic resistance increases there, and the magnetic field passing through the center magnetic body 6 cannot be effectively guided to the outer peripheral side. Since the magnetic field at the center of the four bottoms cancels and weakens, the magnetic field at the center of the bottom of the pan 4 does not increase even if the second-stage inner peripheral heating coil 1c is provided on the inner peripheral side.
[0034]
As described above, a substantially uniform temperature distribution can be realized while suppressing an increase in the outer diameter and weight of the coil portion due to the synergistic effect of the constituent requirements of the above six items.
Here, the predetermined distance between the outer peripheral side heating coil 1a and the inner peripheral side heating coil 1b and the second stage outer peripheral side heating coil 1d and the second stage inner peripheral side heating coil 1c by the coilless portions 9 and 19 is the bottom. When the pan 4 having substantially the same thickness and the same composition material at the bottom and the pan bottom reaching the outer peripheral side of the outer peripheral side heating coil 1a is placed, the bottom of the pan 4 corresponding to the coilless portions 9 and 19 is placed. The magnetic field distribution is substantially uniform with the magnetic field distribution on the bottom of the pan 4 corresponding to each of the outer peripheral side heating coil 1a, the inner peripheral side heating coil 1b, the second stage inner peripheral side heating coil 1c, and the second stage outer peripheral side heating coil 1d. It is set as follows.
[0035]
Thus, the predetermined distance of the coil-free portion 9 secured between the outer peripheral side heating coil 1a and the inner peripheral side heating coil 1b, the second stage outer peripheral side heating coil 1d and the second stage inner peripheral side heating coil 1c, The predetermined distance of the non-coiled portion 19 secured during the period is set to a value that can achieve a remarkable synergistic effect in consideration of the above-described six structural elements, effectively strengthening the magnetic field at the center, and combining the outer peripheral side The effect on the magnetic field is reduced. Such a configuration makes it possible to level the temperature distribution while suppressing an increase in the coil wire diameter and an increase in the coil wire length.
[0036]
FIG. 3 is an enlarged view showing the coil base 2 portion of FIGS. 1 and 2. In FIG. 3, reference numeral 12 denotes a second stage inner peripheral side heating coil 1c, a second stage outer peripheral side heating coil 1d, and the coil base lower surface magnetic body 7. An insulating sheet for insulating. Insulation between the inner peripheral side heating coil 1 b and the second-stage inner peripheral side heating coil 1 c is performed by the coil base 2.
In the case of the structure of FIG. 3, the required length of the second stage inner peripheral side heating coil 1c and the second stage outer peripheral side heating coil 1d is passed through the hole of the coil base 2 through which the crossover wire 11 in FIG. The inner peripheral side heating coil 1c is spirally wound outward from the connecting wire 11 by a necessary number of turns, crossed by the connecting wire 20 to the second outer peripheral side heating coil 1d, and outwards by the required number of turns. Wind in a spiral. The inner peripheral side heating coil 1b is spirally wound outward from the connecting wire 11 by a necessary number of turns, and is passed over the outer peripheral side heating coil 1a by the connecting wire 10 and is wound outwardly by the required number of turns. . In this way, the heating coils 1a, 1b, 1c and 1d can be wound in series.
[0037]
In the case of this structure, the second stage inner heating coil 1c is disposed on the back side of the inner heating coil 1b, and the second stage outer heating coil 1d is disposed on the back side of the outer heating coil 1a. A single-stage coil may be wound on each side of the table 2. Further, since the second-stage inner peripheral heating coil 1c and the second-stage outer peripheral heating coil 1d are the lower surface of the coil base 2, the heat radiation of the second-stage inner peripheral heating coil 1c and the second-stage outer peripheral heating coil 1d. Is effective. In addition, since the coil base lower surface magnetic body 7 supports the second-stage outer peripheral heating coil 1d from below, there is no fear of the coil being collapsed, and the magnetic field is well guided to the outside.
[0038]
Embodiment 2. FIG.
FIG. 4 is an enlarged cross-sectional view showing another embodiment of FIG. In the present embodiment, the coil winding method is different from that of the first embodiment. In FIG. 4, the second stage inner peripheral side is passed through the hole of the coil base 2 pierced at the same position as in FIG. 2 by the required length of the second stage inner peripheral side heating coil 1 c. The heating coil 1c is spirally wound outward from the connecting wire 11 by a necessary number of turns and pulled downward. The inner peripheral side heating coil 1b is spirally wound outward from the connecting wire 11 by a necessary number of turns, and is passed over the outer peripheral side heating coil 1a by the connecting wire 10 and is wound outwardly by the required number of turns. . The second stage outer peripheral side heating coil 1d is wound inwardly by the necessary number of turns inside the second stage outer peripheral side heating coil 1d through the crossover through the hole drilled in the coil base 2 on the outer side. Pull it down. In this way, the heating coils 1a, 1b, 1c and 1d can be wound in series.
[0039]
In the case of this structure, the second-stage inner periphery side heating coil 1c and the second-stage outer periphery side heating coil 1d are formed by winding a coil that passes through different holes of the coil base 2, so The length of the wire passing through each hole can be shortened, improving the manufacturability. Further, the second stage inner peripheral heating coil 1c is disposed on the back side of the inner peripheral heating coil 1b, and the second stage outer peripheral heating coil 1d is disposed on the rear side of the outer peripheral heating coil 1a. One-stage coils may be wound on both sides. Further, since the second-stage inner peripheral heating coil 1c and the second-stage outer peripheral heating coil 1d are the lower surface of the coil base 2, the heat radiation of the second-stage inner peripheral heating coil 1c and the second-stage outer peripheral heating coil 1d. Is effective. In addition, since the coil base lower surface magnetic body 7 supports the second-stage outer peripheral heating coil 1d from below, there is no fear of the coil being collapsed, and the magnetic field is well guided to the outside.
[0040]
Embodiment 3 FIG.
FIG. 5 is an enlarged cross-sectional view showing another embodiment of FIG. In the figure, the inner peripheral heating coil 1b and the second stage inner peripheral heating coil 1c, the outer peripheral heating coil 1a and the second outer peripheral heating coil 1d are arranged on the upper surface side (the pan 4 side) of the coil base 2. ing. 2a is formed on the outer side of the upper surface of the coil base 2 and accommodates the outer peripheral side heating coil 1a, 2b is formed on the inner side of the upper surface of the coil base 2 and accommodates the inner peripheral side heating coil 1b, and 13 is the inner peripheral side. It is an insulating sheet that insulates the heating coil 1b from the second-stage inner peripheral heating coil 1c. Coil bases for securing the upper end surfaces of the inner peripheral heating coil 1b and the outer peripheral heating coil 1a housed in the recesses 2a and 2b and the coilless portion 9 between the inner peripheral heating coil 1b and the outer peripheral heating coil 1a. 2 is substantially the same height as the upper end surface of the convex portion 2c, and a substantially flat surface is formed by the insulating sheet 13, and the second-stage inner peripheral heating coil 1c and the second-stage outer peripheral heating coil 1d are insulating sheets. 13 on the same plane. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.
[0041]
In the case of the structure shown in FIG. 5, the inner peripheral heating coil 1 b and the outer peripheral heating coil 1 a are insulated from the coil base lower surface magnetic body 7 by the coil base 2 interposed therebetween. In addition, as the winding process, the inner circumference side heating coil 1b is required from the inside first, leaving extra line lengths for the second stage inner circumference side heating coil 1c and the second stage outer circumference side heating coil 1d. The outer winding coil 1a is wound around the outer peripheral side heating coil 1a by the connecting wire 10, and the necessary winding number is wound outwardly. A groove serving as a guide is formed in the convex portion 2c where the crossover wire 10 passes.
[0042]
Next, the insulating sheet 13 is placed, passed through an inner notch portion of the insulating sheet 13 (not shown), and wound in a spiral shape from the inner side of the second-stage inner peripheral heating coil 1c toward the outer side by a necessary number of turns. When the coil is wound spirally from the inner side of the second stage outer peripheral side heating coil 1d to the outer side by the required number of turns, the series winding of the heating coils 1a, 1b, 1c, 1d is performed. Can do.
In the case of the structure according to the present embodiment, the winding work can be performed on one side (upper surface side) of the coil base 2, so that there is an effect that the workability of the winding work is good.
[0043]
Embodiment 4 FIG.
FIG. 6 is an enlarged cross-sectional view showing another embodiment of FIG. In the figure, an inner peripheral heating coil 1b, a second stage inner peripheral heating coil 1c, an outer peripheral heating coil 1a, and a second outer peripheral heating coil 1d are arranged on one side (upper surface side) of the coil base 2. Then, it is the same as that of Embodiment 3. In the present embodiment, the winding is performed so that the numbers attached to the coil cross sections in the drawing are in the winding order. That is, from the inside, the inner side heating coil 1b and the second stage inner circumference side heating coil 1c start to wind outward alternately so that the number of turns is larger than that of the second stage inner circumference side heating coil 1c. When the peripheral side heating coil 1b is wound to the outside, it is passed to the inside of the peripheral side heating coil 1a by the connecting wire 10.
[0044]
Next, the outer peripheral side heating coil 1a is wound from the inner side toward the outer side, and when it reaches the overlapping portion with the second stage outer peripheral side heating coil 1d, the outer peripheral side heating coil 1a and the second stage outer peripheral side heating coil 1d are alternately turned from the inner side. Wind outward so that the winding becomes. In this way, a coil with a close winding order is adjacent to an arbitrary coil.
Since the winding order of adjacent coils becomes close by such a winding method, the potential difference between adjacent coils becomes relatively small, and the inner circumference side heating coil 1b and the second stage inner circumference side heating coil 1c become smaller. An insulating sheet between the outer peripheral heating coil 1a and the second outer peripheral heating coil 1d can be eliminated.
[0045]
Embodiment 5. FIG.
FIG. 7 is an enlarged sectional view showing another embodiment of FIG. In the figure, an inner peripheral heating coil 1b, a second stage inner peripheral heating coil 1c, an outer peripheral heating coil 1a, and a second outer peripheral heating coil 1d are arranged on one side (upper surface side) of the coil base 2. Then, it is the same as that of Embodiment 3. In this embodiment, first, the wire length for the second inner circumferential heating coil 1c is left, the inner circumferential heating coil 1b is wound from the inner side to the outer side, and the outer circumferential heating coil is connected by the connecting wire 10 from the outer side. The outer peripheral side heating coil 1a is wound from the inner side to the outer side. Thereafter, an insulating sheet is placed on the inner peripheral heating coil 1b and the outer peripheral heating coil 1a, and is passed upward from the outer peripheral side of the outer peripheral heating coil 1a.
[0046]
Next, the second stage outer peripheral side heating coil 1d is wound from the outer side to the inner side by the required number of turns, and when it reaches the inner side, it is not shown from the coilless portion 9 between the inner peripheral side heating coil 1b and the outer peripheral side heating coil 1a. The hole drilled in the coil base 2 is penetrated and pulled out to the opposite side (lower surface side) of the coil base 2.
As for the inner circumference side, it passes upward from the inner circumference side of the inner circumference side heating coil 1b, winds the second-stage inner circumference side heating coil 1c from the inner side to the outer side as many times as necessary, A hole drilled in the coil base 2 (not shown) is penetrated from the coilless portion 9 between the side heating coil 1b and the outer peripheral side heating coil 1a and pulled out to the opposite side (lower surface side) of the coil base 2.
[0047]
With such a winding method, the winding work can be performed only on the upper surface side of the coil base 2, and the workability is improved. Further, since the coil is pulled out from the coilless portion 9 to the opposite side (lower surface side) of the coil base 2, it is not necessary to lead out the lead wire to the outside of the coil base, and it can be reduced in the planar direction. Further, since the two lead wires can be gathered together in the coilless portion 9, wiring is facilitated.
[0048]
Embodiment 6 FIG.
FIG. 8 is an enlarged cross-sectional view showing another embodiment of FIG. In the figure, 2f is a convex portion provided on the lower surface side of the coil base 2 for restricting the outer peripheral side of the second-stage inner peripheral heating coil 1c or the inner peripheral side of the second-stage outer peripheral heating coil 1d. Thus, the lower surface side of the coil base 2 between the convex portions 2f is cut away. 7a is a ferrite coil base lower surface magnetic body provided below the second-stage inner peripheral heating coil 1c and the convex portion 2f, and 7b is a notch portion between the convex portions 2f and corresponds to the no-coil portion 19 The coil base lower surface magnetic body 7c provided in the portion to be covered is a ferrite coil base lower surface magnetic body 7c provided below the second stage outer peripheral side heating coil 1d and the convex portion 2f. , 7b, 7c are arranged with a slight overlap in the radial direction. The second-stage inner peripheral heating coil 1c, the second-stage outer peripheral heating coil 1d, and the coil base lower surface magnetic body 7b are located on the same plane. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.
[0049]
With this configuration, the coil base lower surface magnetic body 7a is connected to the central magnetic body 6 on the lower side of the second-stage inner peripheral heating coil 1c, and the coil base lower surface magnetic body 7b to the magnetic path closer to the outer periphery. Similarly, the coil base lower surface magnetic body 7c effectively connects the coil base lower surface magnetic body 7b and the magnetic path closer to the lower inner periphery of the second stage outer peripheral heating coil 1d.
And since the coil base lower surface magnetic body 7b is disposed close to the back side of the coil base 2 from the outer periphery of the second stage inner peripheral side heating coil 1c to the second stage outer peripheral side heating coil 1d, the magnetic coupling with the pan is achieved. This increases the heating efficiency.
5-7, the coil base lower surface magnetic body 7b may be disposed substantially flush between the outer peripheral heating coil 1a and the inner peripheral heating coil 1b.
[0050]
【The invention's effect】
As described above, according to the present invention, the inner peripheral side heating coil and the outer peripheral side heating coil are disposed at a predetermined distance from each other, and the inner peripheral side step is arranged in a plurality of stages with the inner peripheral side heating coil. A coil is provided, and an outer peripheral side coil is provided so as to be wound in a plurality of stages with the outer peripheral side heating coil, and each coil has a heating coil in which the same current flows simultaneously in the same direction, and the inner peripheral A central magnetic body disposed in a step direction inside the side heating coil and the inner peripheral side step coil, and an inner peripheral side disposed below the heating coil from the inner peripheral heating coil to the outer peripheral heating coil. Since the lower end magnetic body is in contact with or close to the central magnetic body, the effect of being able to make an electromagnetic cooker with a good temperature distribution while suppressing an increase in the outer diameter and weight of the coil section is obtained. It is done.
[0051]
Moreover, since the spacer is provided between the inner peripheral side heating coil and the outer peripheral side heating coil, the effect that the heating coil can be positioned with high accuracy is obtained.
[0052]
In addition, since the inner end shape of the lower magnetic body is matched with the outer shape of the opposing central magnetic body, the magnetic field at the central portion can easily pass and the effect of improving heating efficiency can be obtained.
[0053]
In addition, a predetermined distance between the inner peripheral heating coil and the outer peripheral heating coil is set so that the magnetic field distribution on the pan bottom corresponding to the gap between the inner peripheral heating coil and the outer peripheral heating coil is equal to the inner peripheral heating coil and outer peripheral heating. Since it is set to be substantially uniform with the magnetic field distribution of the pan bottom corresponding to each of the coils, an effect of making an electromagnetic cooker having a good temperature distribution can be obtained while suppressing an increase in the outer diameter and weight of the coil portion.
[0054]
In addition, a coil base for arranging the heating coil is provided, and the inner peripheral side heating coil and the outer peripheral side heating coil are arranged on substantially the same surface on the pan mounting side of the coil base, and the inner peripheral side step coil and the outer peripheral side step Since the coil is arranged on the opposite side of the coil base on the same side as the pan mounting side, the coil base can be easily insulated from the inner peripheral heating coil and the outer peripheral heating coil and the step coil. It is done.
[0055]
Further, since the spacer is provided between the inner peripheral side step coil and the outer peripheral side step coil, the effect that the step coil can be accurately positioned is obtained.
[0056]
Moreover, since the inner peripheral side step coil, the inner peripheral side heating coil, the outer peripheral side heating coil, and the outer peripheral side step coil are connected in series and both terminals are pulled out to one side of the coil base, the coil terminals are integrated. While improving manufacturability, the effect that the apparatus can be reduced in size can be obtained.
[0057]
In addition, the inner circumference side step coil, the inner circumference side heating coil, the outer circumference side heating coil and the outer circumference side step coil are connected in series, and the terminal is pulled out from the inner circumference side step coil and the outer circumference side step coil. The length of the penetrating line is short, and the effect of improving the manufacturability is obtained.
[0058]
Also, an inner peripheral side step coil, an inner peripheral side heating coil, an outer peripheral side heating coil, and an outer peripheral side step coil are arranged on one side of the coil base, and the inner peripheral side heating coil is connected to the coil base and the coil inner peripheral side. The outer peripheral heating coil is positioned between the coil base and the outer peripheral step coil, and the inner peripheral step coil and the outer peripheral step coil are disposed on substantially the same plane. Therefore, the effect of improving the workability of the winding can be obtained.
[0059]
In addition, since the coils are wound in the order of adjacent coils in the step direction, an effect of reducing the potential difference between the adjacent coils can be obtained.
[0060]
In addition, the workability of the winding is improved because the terminal is drawn from the inner peripheral side coil and outer peripheral side coil through the inner peripheral side heating coil and outer peripheral side heating coil to the opposite side of the coil base. In addition, since the coil terminals are integrated, the manufacturability is improved, and the apparatus can be further downsized.
[0061]
Moreover, since the lower surface magnetic body is disposed on the same plane as the inner peripheral side step coil and the outer peripheral side step coil, the magnetic coupling is strengthened and the effect of improving the heating efficiency can be obtained.
[Brief description of the drawings]
FIG. 1 (a) is a cross-sectional view showing an electromagnetic cooking device according to Embodiment 1 of the present invention.
(B) It is a temperature distribution figure which shows the temperature distribution of the radial direction of the pan bottom in Fig.1 (a).
2 (a) is a top view of a portion of the electromagnetic cooker of FIG. 1 (a) excluding a top plate and a heat insulating material.
(B) It is a bottom view of the electromagnetic cooking device of Fig.1 (a).
3 is an enlarged cross-sectional view showing a coil base portion in FIGS. 1 and 2; FIG.
FIG. 4 is an enlarged cross-sectional view showing an electromagnetic cooker in Embodiment 2 of the present invention.
FIG. 5 is an enlarged cross-sectional view showing an electromagnetic cooker in Embodiment 3 of the present invention.
FIG. 6 is an enlarged cross-sectional view showing an electromagnetic cooking device according to Embodiment 4 of the present invention.
FIG. 7 is an enlarged cross-sectional view showing an electromagnetic cooker in Embodiment 5 of the present invention.
FIG. 8 is a partial plan view showing an electromagnetic cooking device according to Embodiment 6 of the present invention.
FIG. 9 (a) is a cross-sectional view showing a conventional electromagnetic cooker.
(B) It is a temperature distribution figure which shows the temperature distribution of the radial direction of the pan bottom in Fig.9 (a).
FIG. 10A is a cross-sectional view showing another conventional electromagnetic cooker.
(B) It is a temperature distribution figure which shows the temperature distribution of the radial direction of the pan bottom in Fig.10 (a).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heating coil, 1a Outer peripheral side heating coil, 1b Inner peripheral side heating coil, 1c Inner peripheral side second stage heating coil, 1d Outer peripheral side second stage heating coil, 2 Coil stand, 2a, 2b, 2d, 2e Storage part, 2c, 2f Convex part, 3 Top plate, 4 Pan, 5 Heated object, 6 Center part magnetic body, 7 Coil base bottom surface magnetic body, 8 Thermal insulation, 9, 19 Coilless part, 10, 11, 20 Crossover, 12, 13 Insulating sheet.

Claims

A coil base is provided, and the shape of the surface of the coil base on the pan mounting side is a concave shape at the part facing the inner peripheral side and the outer peripheral side of the heating coil, and an intermediate part between the inner peripheral side and the outer peripheral side. Is formed in a convex shape, and the inner peripheral side heating coil and the outer peripheral side heating coil are arranged at a predetermined distance so that the convex middle part of the coil base becomes a spacer, and the inner peripheral side of the coil base a groove for the inner peripheral side step coil is formed on the coil base surface opposite to the concave portion, the inner peripheral side heating coil and the inner peripheral side step coil so that a plurality of stages winding the groove is disposed, the A groove for the outer peripheral side step coil is formed on the coil base surface on the opposite side of the outer peripheral peripheral concave portion of the coil base, and the outer peripheral side step coil is disposed in this groove so as to be multi-stage wound with the outer peripheral side heating coil. A heating coil in which currents of the same magnitude simultaneously flow in the same direction in each coil; The central part magnetic body disposed over the inner circumferential side heating coil and the inner circumferential side step coil over the step direction, and disposed below the heating coil from the inner circumferential side heating coil to the outer circumferential side heating coil, An electromagnetic cooker comprising an inner peripheral side end portion and a lower magnetic body in contact with or close to the central magnetic body.

The electromagnetic cooker according to claim 1, wherein the inner end shape of the bottom magnetic body is matched to the outer shape of the opposing central magnetic body.

The magnetic field distribution on the pan bottom corresponding to the gap between the inner peripheral heating coil and the outer peripheral heating coil is a predetermined distance between the inner peripheral heating coil and the outer peripheral heating coil. 2. An electromagnetic cooker according to claim 1, wherein the electromagnetic cooker is set so as to be substantially uniform with the magnetic field distribution of the pan bottom corresponding to each.

The inner peripheral side step coil, the inner peripheral side heating coils, to connect the outer peripheral side heating coil and the outer stage coil in series, according to claim 1 or 3, wherein both terminal is characterized in that the drawer to one side of the coil block Electromagnetic cooker.

The inner circumference side stage coil, the inner circumference side heating coil, the outer circumference side heating coil, and the outer circumference side stage coil are connected in series, and the terminal is pulled out from the inner circumference side stage coil and the outer circumference side stage coil. The electromagnetic cooker according to 1 .

The electromagnetic cooker according to claim 5, wherein the coils are wound in the order of coils adjacent in the step direction.

Electromagnetic according to claim 1, wherein a drawn out on the opposite side of the coil board passes between the inner circumferential side heating coil and the outer heating coil terminal from the inner peripheral side step coil and the outer peripheral side step coil Cooking device.

The electromagnetic cooker according to any one of claims 1 to 7 , wherein a lower magnetic body is disposed on the same plane as the inner peripheral side step coil and the outer peripheral side step coil.