JP3707181B2 - Induction heating apparatus and method - Google Patents

Induction heating apparatus and method Download PDF

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JP3707181B2
JP3707181B2 JP01417197A JP1417197A JP3707181B2 JP 3707181 B2 JP3707181 B2 JP 3707181B2 JP 01417197 A JP01417197 A JP 01417197A JP 1417197 A JP1417197 A JP 1417197A JP 3707181 B2 JP3707181 B2 JP 3707181B2
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induction heating
group
coil
transformer
switching
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JPH10208861A (en
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弘 鈴木
伸治 倉知
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Toyota Motor Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description

【０００１】
【発明の属する技術分野】
本発明は、誘導加熱装置及び方法に関し、特に、複数の誘導加熱コイルを使用し、小型で、均一な加熱をすることができる誘導加熱装置及び方法に関するものである。
【０００２】
【従来の技術】
高周波誘導加熱方式では、高周波発振電源より出力された高周波電流を高周波共振トランスを介して誘導加熱コイルに大電流を流す。その電流により、コイル近傍のワーク（例えば金属部品）に渦電流を発生させて、その渦電流により発生するジュール熱により、金属部品を加熱（焼き入れ、溶融、余熱）する。また、高周波（数ｋＨｚ〜数百ＭＨｚ）の大電流を流すので、大型の高周波発生電源装置や、出力トランスが必要になる。
【０００３】
図６に示すように、ワ−ク５４（この場合鋼板）を加熱する場合では、高周波電源５０はケーブル５１を介してトランス５２に接続され、更に、トランス５２を経て誘導加熱コイル５３に接続されている。ワーク５４は誘導加熱コイル５３により加熱される。このとき、誘導加熱コイル５３は、ワーク５４の近傍に沿って矢印５５方向に移動させられる。
【０００４】
また、図７に示すように、ワーク６４の加熱する部位に複数台の誘導加熱コイル６３ａ〜６３ｃ、トランス６２ａ〜６２ｃ及び高周波電源６０ａ〜６０ｃを配置する方法がある。
図７において、高周波電源６０ａはケーブル６１ａを介してトランス６２ａに接続され、更に、トランス６２ａを経て、誘導加熱コイル６３ａに接続されている。同様に、高周波電源６０ｂはケーブル６１ｂを介してトランス６２ｂに接続され、更に、トランス６２ｂを経て、誘導加熱コイル６３ｂに接続されている。
更に、高周波電源６０ｃはケーブル６１ｃを介してトランス６２ｃに接続され、更に、トランス６２ｃを経て、誘導加熱コイル６３ｃに接続されている。ワーク６４は誘導加熱コイル６３ａ、６３ｂ、６３ｃにより加熱される。
【０００５】
【発明が解決しようとする課題】
しかしながら、ワークを高周波誘導加熱（焼き入れ、溶融、余熱）する場合、図６に示す誘導加熱コイル移動式では、図８に示すように誘導加熱コイル８１（誘導加熱コイル５３に相当する。）の形状が固定され、更に、ワーク８２（ワーク５４に相当する。）の凹凸形状が固定されるため、ワーク８２の凹凸形状が複雑なものでは、誘導加熱を均一に行うことができない。このため、誘導加熱コイル８１により加熱される部位である焼き入れ部位８２ａ、８２ｂ、８２ｃは、ワーク８２の全体ではなく、ワーク８２の一部分となるという欠点があった。
更に、図７に示すように、複数台の誘導加熱コイル６３ａ〜６３ｃ、トランス６２ａ〜６２ｃ及び高周波電源６０ａ〜６０ｃを配置する場合は、ワーク６４の凹凸に合わせて誘導加熱コイル６３ａ〜６３ｃを配置することができ、加工も早くなるが、１つの誘導加熱コイル６３ａ〜６３ｃでの加工範囲が狭いため、ワーク６４の加工部位が広い（数十ｍｍ以上）と設備内でのトランス６２ａ〜６２ｃと誘導加熱コイル６３ａ〜６３ｃの配置が困難となる。また、設備が成り立っても、非常に高価なものになるという欠点があった。
従って、本願発明の目的は、上述の従来例の欠点をなくし、複数の誘導加熱コイルを使用し、小型でワークを均一に加熱できる誘導加熱装置及び方法を提供することである。
【０００６】
【課題を解決するための手段】
上記課題を解決するため、本願の第１の発明の構成は、第１グループの誘導加熱コイル群と第２グループの誘導加熱コイル群と前記第１グループの誘導加熱コイル群に接続可能な第１トランス及び前記第２グループの誘導加熱コイル群に接続可能な第２トランスとを備え、ワークの加熱部位に合わせて前記第１グループの誘導加熱コイルと前記第２グループの誘導加熱コイルを交互に配置し、高周波電源と前記第１及び第２グループの誘導加熱コイル群との接続切換を行うトランス切換手段を設け、更に、前記各トランスと前記各誘導加熱コイルとを接続する移動型接続手段と該移動型接続手段の移動を制御する移動制御手段とを設けたことを特徴とする誘導加熱装置である。
【０００９】
上記第１の発明の構成により、第１グループの誘導加熱コイル群と第２グループの誘導加熱コイル群と前記第１グループの誘導加熱コイル群に接続可能な第１トランス及び前記第２グループの誘導加熱コイル群に接続可能な第２トランスとを備えているので、前記第１グループの誘導加熱コイル群に第１トランスを介して通電し、前記第２グループの誘導加熱コイル群に第２トランスを介して通電することができる。
更に、ワークの加熱部位に合わせて前記第１グループの誘導加熱コイルと前記第２グループの誘導加熱コイルを交互に配置しているので、ワークを互いに隣接する第１グループの誘導加熱コイルと第２グループの誘導加熱コイルとで交互に加熱することができる。
更に、高周波電源と前記第１及び第２グループの誘導加熱コイル群との接続切換を行うトランス切換手段を設けているので、トランス切換手段により高周波電源を前記第１及び第２グループの誘導加熱コイルの接続を切り換えることができる。
更に、前記各トランスと前記各誘導加熱コイルとを接続する移動型接続手段と該移動型接続手段の移動を制御する移動制御手段とを設けたので、該移動型接続手段により発熱する誘導加熱コイルの切換を順次行うので、誘導加熱装置全体の小型化とワークの均一な加熱が可能になる。
【００１２】
更に、第２の発明の構成は、ワークの加熱部位に合わせて第１グループの誘導加熱コイルと第２グループの誘導加熱コイルを交互に配置し、高周波電源に前記第１グループ及び第２グループの誘導加熱コイルをそれぞれ切換スイッチを介して接続し、前記第１グループ及び第２グループの誘導加熱コイルに流す電流を順次切り換え、隣り合う前記誘導加熱コイルの電流切換に際して、該電流切換前に通電している前記誘導加熱コイルと該電流切換後に通電する前記誘導加熱コイルとの両方の通電を所定時間ラップさせることを特徴とする誘導加熱方法である。
【００１３】
上記第２の発明の構成による誘導加熱方法により、ワークの加熱部位に合わせて第１グループの誘導加熱コイルと第２グループの誘導加熱コイルを交互に配置しているので、互いに隣接する第１グループの誘導加熱コイルと第２グループの誘導加熱コイルにより交互にワークを加熱することができる。
更に、切換スイッチによる誘導加熱コイルの電流切換に際して、該電流切換前に通電している前記誘導加熱コイルと該電流切換後に通電する前記誘導加熱コイルとの両方の通電を所定時間ラップさせるので、電流切換前の誘導加熱コイルによる誘導発熱領域から電流切換後の誘導加熱コイルによる誘導発熱領域への移行を安定に行うことができる。
【００１６】
【発明の実施の形態】
次に、本願発明の実施の形態を図面を参照して説明する。図１は該実施の形態を示す。なお、図１において、（ａ）は該実施の形態の概略を示し、（ｂ）は誘導加熱コイルとワークを示す。図２は、該実施の形態の動作を説明し、図３は該実施の形態の詳細を示し、図４は図３に示すものの動作を説明し、図５は該実施の形態の変形例の動作を示している。
図１（ａ）において、出力トランス２１は図示しない高周波電源から高周波電力を受けている。切換スイッチ２２は、該高周波電力を各誘導加熱コイル２３（ａ1 、ａ2 、ａ3 、ａ4 のようにａ側の誘導加熱コイル）に切り換えるものである。
更に、出力トランス３１は図示しない高周波電源から高周波電力を受けている。切換スイッチ３２は、該高周波電力を各誘導加熱コイル３３（ｂ1 、ｂ2 、ｂ3 のようにｂ側の誘導加熱コイル）に切り換えるものである。
ワーク１０は、誘導加熱コイル２３、３３により加熱される。なお、矢印２４はａ側誘導加熱コイル２３の切換方向を示し、矢印３４はｂ側誘導加熱コイル３３の切換方向を示す。
図１（ｂ）に示すように、誘導加熱コイル２３（及び３３）とワーク１０との間にクリアランスＬが設けられている。ワーク１０の厚さは、例えば０．９ｍｍである。
【００１７】
図２において、誘導加熱コイル（以下各図の説明において「コイル」とする。）ａ1 の加熱領域はｃ1 であり、コイルｂ1 の加熱領域はｃ2 である。更に、コイルａ2 の加熱領域はｃ3 であり、コイルｂ2 の加熱領域はｃ4 である。誘導発熱領域は、ｃ1 、ｃ2 、ｃ3 、ｃ4―方向に順次移動する。
ａ側トランス２１の出力及びｂ側トランス３１の出力は図示のように切り替わる。更に、ａ側コイル２３及びｂ側コイル３３が図示のように切り替わる。コイルａ１、コイルｂ１、コイルａ２及びコイルｂ２には図示のように順次高周波（例えば４００ｋＨｚ）電流Ｉｐが流れる。なお、電流Ｉｐは、例えば２０００〜３０００Ａである。
【００１８】
即ち、コイルｂ1 に電流Ｉｐを流し、コイルａ1 の電流Ｉｐが切れている間にａ側のコイルをコイルａ1 からコイルａ2 に切り換える。次に、コイルａ2 に電流Ｉｐを流し、コイルｂ1 の電流が切れている間にｂ側のコイルをコイルｂ1 からコイルｂ2 に切り換える。
これを繰り返すことにより、ワーク１０における誘導発熱領域の移動を切れ間なく安定して制御することができる。
コイルａ、ｂに流す電流Ｉｐは、ワーク１０の材質、形状により電流Ｉｐをラップ（ラップ時間ＴL ）させながら切り換える。またコイルに対して電流Ｉｐを供給するための出力トランス２１、３１と高周波電源との台数関係は、
コイルの数＞出力トランス２１、３１の数≧高周波電源の数
となる。
【００１９】
図３において、高周波電源４０は、トランス切換装置４１によりトランス２１及びトランス３１に接続される。コイル切換コントローラ４２はトランス切換装置４１の制御信号（後述するＩＧＢＴ４１ａ〜４１ｄの制御信号）をトランス切換装置４１に加えるとともに、駆動切換装置４３を制御する。なお、４４は駆動切換装置４３の駆動用電源である。駆動切換装置４３は移動連結ユニット４５、４６のモータ４５ｃ、４６ｃを駆動する。
トランス切換装置４１は、電力用スイッチング素子としてのＩＧＢＴ４１ａ〜４１ｄとダイオード４１ｅ〜４１ｈが逆並列に接続されている。直列に接続されたＩＧＢＴ４１ａ、４１ｂがコンデンサ２１ａを介してトランス２１に接続され、一方直列に接続されたＩＧＢＴ４１ｃ、４１ｄがコンデンサ３１ｂを介してトランス３１に接続されている。なお、ダイオード４１ｅ〜４１ｈはＩＧＢＴ４１ａ〜４１ｄの保護用である。
コンデンサ２１ａ、２１ｂはトランス２１と直接共振回路（高周波電源４０の周波数と共振する。）を形成し、コンデンサ３１ａ、３１ｂはトランス３１と前記直列共振回路を形成している。
低インピーダンスブース５１はトランス２１と各端子５３（１０個の端子５３が図示されている。）とを接続し、低インピーダンスブース５２はトランス３１と各端子５４（１０個の端子５４が図示されている。）とを接続している。
【００２０】
移動連結ユニット４５は、絶縁ベース４５ａ、連結電極４５ｂ、モータ４５ｃ及びねじ状部材４５ｄからなる。連結電極４５ｂは絶縁ベース４５ａ上に配設されている。絶縁ベース４５ａはねじ状部材４５ｄに螺合しているので、モータ４５ｃがねじ状部材４５ｄを回転させると、絶縁ベース４５ａは矢印４５ｅ方向に移動する。このため、連結電極４５ｂが低インピーダンスブース５１及び端子５３を介してトランス２１と接続するコイル２３がコイルａ1 、コイルａ2 、コイルａ3 ─と順次切り替わる。
同様に、移動連結ユニット４６は、絶縁ベース４６ａ、連結電極４６ｂ、モータ４６ｃ及びねじ状部材４６ｄからなる。連結電極４６ｂは絶縁ベース４６ａ上に配設されている。絶縁ベース４６ａはねじ状部材４６ｄに螺合しているので、モータ４６ｃがねじ状部材４６ｄを回転させると、絶縁ベース４６ａは矢印４６ｅ方向に移動する。このため、連結電極４６ｂが低インピーダンスブース５２及び端子５４を介してトランス３１と接続するコイル３３がコイルｂ1 、コイルｂ2 、コイルｂ3 ─と順次切り替わる。なお、矢印４７は、このときの発熱領域移動の方向を示す。
【００２１】
図４において、高周波電源４０、ａ側トランス２１の切換、ｂ側トランス３１の切換、ａ側コイル２３の切換、ｂ側コイル３３の切換、コイルａ1 、ｂ1 、ａ2 、ｂ2 の電流Ｉｐの切換が表示されている。
はじめにスタートＰ1 のタイミングで、トランス切換装置４１によりａ側のトランス２１をオンし、高周波電源４０よりコイルａ1 に高周波電流Ｉｐを流し、ワーク１０に誘導発熱領域ｃ1 を形成する。
次に、Ｐ2 のタイミングで高周波電源４０よりの高周波電力の供給をオフし、トランス切換装置４１のａ側トランス２１をオフし、ｂ側トランス３１をオン後、再度、高周波電源４０よりの高周波電力の供給をオンし、コイルｂ1 に電流Ｉｐを流し、ワーク１０に誘導発熱領域ｃ2 を形成する。
そして、コイルｂ1 に電流Ｉｐを流している途中のＰ3 のタイミングで、移動連結ユニット４５を移動させて、トランス２１に接続されるコイルをコイルａ1 からコイルａ2 に切り換え、コイルａ2 の電流オンを待つ。
Ｐ4 のタイミングで、高周波電源４０よりの高周波電力の供給をオフし、トランス切換装置４１のｂ側トランス３１をオフし、ａ側トランス２１をオン後、再度、高周波電源４０よりの高周波電力の供給をオンし、コイルａ2 に電流Ｉｐを流し、ワーク１０に誘導発熱領域ｃ3 を形成する。
【００２２】
そして、コイルａ2 に電流Ｉｐを流している途中のＰ5 のタイミングで、移動連結ユニット４６を移動させて、トランス３１に接続されるコイルをコイルｂ1 からコイルｂ2 に切り換え、コイルｂ2 の通電オンを待つ。
Ｐ6 のタイミングで、高周波電源４０よりの高周波電力の供給をオフし、トランス切換装置４１のａ側トランス２１をオフ、ｂ側トランス３１をオン後、再度、高周波電力の供給をオンし、コイルｂ2 に電流Ｉｐを流し、ワーク１０に誘導発熱領域ｃ4 を形成する。
以上の切換を最終誘導加熱コイルまで繰り返すことにより、ワーク１０に対して高周波による誘導発熱の移動を行うことができる。
【００２３】
図３及び図４の方法で、ワーク１０の材質、形状に左右されず、誘導発熱の移動を安定させることのできるコイル切換方法を図５に示す。
図５において、コイルａ1 からコイルｂ1 に切り替わる時に、コイルａ1 とコイルｂ1 とをコイルａ1 の元来の通電時間Ｔ1 より短い時間Ｔ3 で交互に切り換えて通電（通電時間Ｔ2 ）している。なお、コイルｂ1 の元来の通電時間もＴ1 である。このようにして、コイルａ1 及びコイルｂ1 を電流Ｉｐが流れるように切替わる。
Ｐ2 の切換タイミングで、コイル切換コントローラ４２により高周波電源４０の出力のオン・オフ及びトランス切換装置４１のスイッチング素子となるＩＧＢＴ４１ａ〜４１ｄを制御して、ハード切換接点なしで、高速（周期＜１秒）で、安定した高周波出力切換を実現することにより、ａ側コイル２３及びｂ側コイル３３に連続的なパルス（オン時間Ｔ2 、オフ時間Ｔ3 ）の高周波電流Ｉｐを流すことにより、誘導発熱領域のｃ1 とｃ2 の境界部位にて、誘導発熱不足を解消できる。この方法を、図４の各切替タイミングに加えることにより、どのようなワーク１０に対しても、安定した誘導発熱の移動を実現できる。
【００２４】
以上の構成により、ワーク１０の加熱部位に合わせて配置された複数の誘導加熱コイル２３、３３がワーク１０を誘導加熱する。その際、前記複数の誘導加熱コイル２３、３３に電流を供給する高周波電源４０に前記複数の誘導加熱コイル２３、３３をそれぞれ切換スイッチ２２、３２を介して接続し、前記複数の誘導加熱コイル２３、３３に流す電流を順次切り換えるための前記切換スイッチ２２、３２（トランス切換装置４１が相当する。）の制御部（コイル切換コントーラ４２が相当する。）を備えるので、前記複数の誘導加熱コイル２３、３３に対して前記高周波電源４０を共有し切換制御を行うため、誘導加熱装置全体が小型になる。
【００２５】
更に、第１グループの誘導加熱コイル２３群と第２グループの誘導加熱コイル３３群と前記第１グループの誘導加熱コイル２３群に接続可能な第１トランス２１及び前記第２グループの誘導加熱コイル３３群に接続可能な第２トランス３１とを備えているので、前記第１グループの誘導加熱コイル２３群に第１トランス２１を介して通電し、前記第２グループの誘導加熱コイル３３群に第２トランス３１を介して通電することができる。
更に、ワーク１０の加熱部位に合わせて前記第１グループの誘導加熱コイル２３と前記第２グループの誘導加熱コイル３３を交互に配置しているので、ワーク１０を互いに隣接する第１グループの誘導加熱コイル２３と第２グループの誘導加熱コイル３３とで交互に加熱することができる。
【００２６】
更に、高周波電源４０と前記第１及び第２グループの誘導加熱コイル２３、３３群との接続切換を行うトランス切換手段（トランス切換装置４１が相当する。）を設けているので、トランス切換手段により高周波電源４０と前記第１及び第２グループの誘導加熱コイル２３、３３の接続を切り換えることができる。
更に、前記各トランス２１、３１と前記各誘導加熱コイル２３、３３とを接続する移動型接続手段（移動連結ユニット４５、４６が相当する。）と該移動型接続手段の移動を制御する移動制御手段（駆動切換装置４３が相当する。）とを設けたので、該移動型接続手段により発熱する誘導加熱コイル２３、３３の切換を順次行うため、誘導加熱装置全体の小型化とワーク１０の均一な加熱が可能になる。
【００２７】
更に、第１グループの誘導加熱コイル２３と第２グループの誘導加熱コイル３３との電流切換に際して、該電流切換前に通電している前記誘導加熱コイルと該電流切換後に通電する前記誘導加熱コイルとの両方の通電を所定時間ラップさせるので、誘導発熱領域ｃ1 、ｃ2 等が電流切換前の誘導加熱コイルによるものから電流切換後の誘導加熱コイルによるものへ安定に移行することができる。
更に、高周波電源４０に前記第１グループ及び第２グループの誘導加熱コイル２３、３３をそれぞれ切換スイッチ２２、３２を介して接続し、前記第１グループ及び第２グループの誘導加熱コイル２３、３３に流す電流を順次切り換え、隣り合う前記誘導加熱コイル２３、３３の電流切換に際して、前記誘導加熱コイル２３、３３の元来の通電時間Ｔ1 より短い時間Ｔ3 に前記第１グループの誘導加熱コイル２３と前記第２グループの誘導加熱コイル３３を交互に切り換えて通電するので、第１の誘導加熱コイル２３と第２の誘導加熱コイル３３の切換時においてワーク１０の誘導発熱領域ｃ1 、ｃ2 等の移行を安定に行える。
【００２８】
【発明の効果】
本願の第１の発明に係わる誘導加熱装置によって、発熱するコイルの切換を順次行うので、誘導加熱装置の小型化とワークの均一な加熱が可能になる。
更に、高周波電源１台に対して、複数の出力トランスを接続することができるので、誘導加熱装置の大幅なコスト低減を図ることができる。
更に、第２の発明に係わる誘導加熱方法によれば、誘導加熱コイル切換時のワークの発熱領域の移行を安定に行うことができる。
【図面の簡単な説明】
【図１】本願発明の実施の形態を示している説明図である。
【図２】該実施の形態の動作説明図である。
【図３】該実施の形態の詳細回路図である。
【図４】図３に示すものの動作説明図である。
【図５】該実施の形態の変形例の説明図である。
【図６】従来例の説明図である。
【図７】他の従来例の説明図である。
【図８】従来例の動作説明図である。
【符号の説明】
１０ ワーク
２１、３１ トランス
２２、３２ 切換スイッチ
２３、３３ 誘導加熱コイル
４０ 高周波電源
４１ トランス切換装置
４２ コイル切換コントローラ
４３ 駆動切換装置
４５、４６ 移動連結ユニット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating apparatus and method, and more particularly, to an induction heating apparatus and method that uses a plurality of induction heating coils and can perform uniform heating with a small size.
[0002]
[Prior art]
In the high-frequency induction heating method, a high-frequency current output from a high-frequency oscillation power supply is passed through a high-frequency resonant transformer to the induction heating coil. The current causes an eddy current to be generated in a workpiece (for example, a metal part) in the vicinity of the coil, and the metal part is heated (quenched, melted, remaining heat) by Joule heat generated by the eddy current. In addition, since a large current of a high frequency (several kHz to several hundreds of MHz) flows, a large-sized high-frequency power supply device and an output transformer are required.
[0003]
As shown in FIG. 6, when heating the work 54 (in this case, a steel plate), the high frequency power supply 50 is connected to the transformer 52 via the cable 51 and further connected to the induction heating coil 53 via the transformer 52. ing. The workpiece 54 is heated by the induction heating coil 53. At this time, the induction heating coil 53 is moved in the direction of the arrow 55 along the vicinity of the workpiece 54.
[0004]
In addition, as shown in FIG. 7, there is a method in which a plurality of induction heating coils 63a to 63c, transformers 62a to 62c, and high frequency power supplies 60a to 60c are arranged at a part to be heated of the workpiece 64.
In FIG. 7, the high frequency power supply 60a is connected to a transformer 62a via a cable 61a, and further connected to an induction heating coil 63a via a transformer 62a. Similarly, the high frequency power supply 60b is connected to the transformer 62b via the cable 61b, and further connected to the induction heating coil 63b via the transformer 62b.
Furthermore, the high frequency power supply 60c is connected to the transformer 62c via the cable 61c, and further connected to the induction heating coil 63c via the transformer 62c. The workpiece 64 is heated by induction heating coils 63a, 63b, and 63c.
[0005]
[Problems to be solved by the invention]
However, when the work is subjected to high-frequency induction heating (quenching, melting, remaining heat), the induction heating coil moving type shown in FIG. 6 uses the induction heating coil 81 (corresponding to the induction heating coil 53) as shown in FIG. Since the shape is fixed, and the uneven shape of the work 82 (corresponding to the work 54) is fixed, induction heating cannot be performed uniformly if the uneven shape of the work 82 is complicated. For this reason, there existed a fault that the quenching site | part 82a, 82b, 82c which is a site | part heated by the induction heating coil 81 became a part of the workpiece | work 82 instead of the whole workpiece | work 82.
Further, as shown in FIG. 7, when a plurality of induction heating coils 63 a to 63 c, transformers 62 a to 62 c and high frequency power sources 60 a to 60 c are arranged, the induction heating coils 63 a to 63 c are arranged according to the unevenness of the work 64. However, since the processing range of one induction heating coil 63a to 63c is narrow, if the processing part of the workpiece 64 is wide (several tens of mm or more), the transformers 62a to 62c in the equipment It becomes difficult to arrange the induction heating coils 63a to 63c. Moreover, even if the facilities are established, there is a drawback that it becomes very expensive.
Accordingly, an object of the present invention is to provide an induction heating apparatus and method that can eliminate the drawbacks of the above-described conventional example, can use a plurality of induction heating coils, and can uniformly heat a workpiece.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, the configuration of the first invention of the present application is the first that can be connected to the induction heating coil group of the first group, the induction heating coil group of the second group, and the induction heating coil group of the first group. A transformer and a second transformer connectable to the induction heating coil group of the second group, and the induction heating coil of the first group and the induction heating coil of the second group are alternately arranged in accordance with a heating part of the workpiece. And a transformer switching means for switching the connection between the high-frequency power source and the first and second groups of induction heating coils, and further, movable connection means for connecting the transformers and the induction heating coils; An induction heating apparatus comprising a movement control means for controlling the movement of the movable connection means .
[0009]
According to the configuration of the first aspect of the invention, the first transformer that can be connected to the induction heating coil group of the first group, the induction heating coil group of the second group, and the induction heating coil group of the first group, and the induction of the second group A second transformer that can be connected to the heating coil group, so that the induction heating coil group of the first group is energized via the first transformer, and the second transformer is connected to the induction heating coil group of the second group. It can energize through.
Furthermore, the induction heating coil of the first group and the induction heating coil of the second group are alternately arranged in accordance with the heating part of the workpiece, so that the induction heating coil and the second group of the first group adjacent to each other are arranged. It can be heated alternately with the induction heating coils of the group.
Further, since the transformer switching means for switching the connection between the high-frequency power source and the first and second group induction heating coil groups is provided, the high-frequency power source is supplied to the first and second group induction heating coils by the transformer switching means. Can be switched.
Furthermore, since the moving connection means for connecting the transformers and the induction heating coils and the movement control means for controlling the movement of the moving connection means are provided, the induction heating coils that generate heat by the moving connection means Therefore, the entire induction heating apparatus can be reduced in size and the workpiece can be heated uniformly.
[0012]
Further, according to the configuration of the second invention, the induction heating coil of the first group and the induction heating coil of the second group are alternately arranged according to the heating part of the work, and the first group and the second group of the high frequency power supply are arranged. Each induction heating coil is connected via a changeover switch, and the currents flowing through the induction heating coils of the first group and the second group are sequentially switched. When the currents of the adjacent induction heating coils are switched, the current is switched before the current switching. The induction heating method is characterized in that energization of both the induction heating coil and the induction heating coil energized after the current switching is wrapped for a predetermined time.
[0013]
In the induction heating method according to the second aspect of the invention, the first group of induction heating coils and the second group of induction heating coils are alternately arranged in accordance with the heating part of the workpiece. The induction heating coil and the second group induction heating coil can alternately heat the workpiece.
Further, when the current of the induction heating coil is switched by the changeover switch, the energization of both the induction heating coil energized before the current switching and the induction heating coil energized after the current switching is wrapped for a predetermined time. The transition from the induction heating region by the induction heating coil before switching to the induction heating region by the induction heating coil after switching current can be performed stably.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the embodiment. In FIG. 1, (a) shows an outline of the embodiment, and (b) shows an induction heating coil and a workpiece. 2 illustrates the operation of the embodiment, FIG. 3 illustrates the details of the embodiment, FIG. 4 illustrates the operation of what is shown in FIG. 3, and FIG. 5 illustrates a modification of the embodiment. The operation is shown.
In FIG. 1A, the output transformer 21 receives high frequency power from a high frequency power source (not shown). The change-over switch 22 switches the high-frequency power to each induction heating coil 23 (induction heating coil on the a side like a 1 , a 2 , a 3 , a 4 ).
Further, the output transformer 31 receives high frequency power from a high frequency power source (not shown). The changeover switch 32 switches the high-frequency power to each induction heating coil 33 (induction heating coil on the b side such as b 1 , b 2 , and b 3 ).
The workpiece 10 is heated by the induction heating coils 23 and 33. The arrow 24 indicates the switching direction of the a-side induction heating coil 23, and the arrow 34 indicates the switching direction of the b-side induction heating coil 33.
As shown in FIG. 1B, a clearance L is provided between the induction heating coil 23 (and 33) and the workpiece 10. The thickness of the workpiece 10 is, for example, 0.9 mm.
[0017]
In FIG. 2, the heating region of induction heating coil (hereinafter referred to as “coil” in the description of each drawing) a 1 is c 1 , and the heating region of coil b 1 is c 2 . Further, the heating area of the coil a 2 is c 3 and the heating area of the coil b 2 is c 4 . The induction heat generation area sequentially moves in the c 1 , c 2 , c 3 , c 4 -direction.
The output of the a-side transformer 21 and the output of the b-side transformer 31 are switched as shown in the figure. Further, the a-side coil 23 and the b-side coil 33 are switched as illustrated. Coils a1, coils b1, the coil a2 and coil b2 sequentially frequency (e.g. 400kHz) as illustrated current Ip flows. The current Ip is, for example, 2000 to 3000A.
[0018]
That is, the current Ip is supplied to the coil b 1 , and the coil on the a side is switched from the coil a 1 to the coil a 2 while the current Ip of the coil a 1 is cut off. Next, the current Ip is supplied to the coil a 2 , and the coil on the b side is switched from the coil b 1 to the coil b 2 while the current of the coil b 1 is cut off.
By repeating this, the movement of the induction heat generation area in the workpiece 10 can be stably controlled without interruption.
The current Ip flowing through the coils a and b is switched while wrapping the current Ip (wrap time T L ) depending on the material and shape of the workpiece 10. The number relationship between the output transformers 21 and 31 for supplying the current Ip to the coil and the high frequency power supply is as follows.
The number of coils> the number of output transformers 21 and 31 ≧ the number of high-frequency power supplies.
[0019]
In FIG. 3, the high frequency power supply 40 is connected to the transformer 21 and the transformer 31 by a transformer switching device 41. The coil switching controller 42 applies a control signal of the transformer switching device 41 (control signals of IGBTs 41 a to 41 d described later) to the transformer switching device 41 and controls the drive switching device 43. Reference numeral 44 denotes a drive power source for the drive switching device 43. The drive switching device 43 drives the motors 45c and 46c of the moving connection units 45 and 46.
In the transformer switching device 41, IGBTs 41a to 41d as power switching elements and diodes 41e to 41h are connected in antiparallel. The IGBTs 41a and 41b connected in series are connected to the transformer 21 via the capacitor 21a, while the IGBTs 41c and 41d connected in series are connected to the transformer 31 via the capacitor 31b. The diodes 41e to 41h are for protecting the IGBTs 41a to 41d.
The capacitors 21a and 21b directly form a resonance circuit (resonates with the frequency of the high frequency power supply 40) with the transformer 21, and the capacitors 31a and 31b form the series resonance circuit with the transformer 31.
The low impedance booth 51 connects the transformer 21 and each terminal 53 (10 terminals 53 are shown), and the low impedance booth 52 is the transformer 31 and each terminal 54 (10 terminals 54 are shown). Connected).
[0020]
The moving connection unit 45 includes an insulating base 45a, a connection electrode 45b, a motor 45c, and a screw-like member 45d. The connecting electrode 45b is disposed on the insulating base 45a. Since the insulating base 45a is screwed with the threaded member 45d, when the motor 45c rotates the threaded member 45d, the insulating base 45a moves in the direction of the arrow 45e. Therefore, the coil 23 in which the connecting electrode 45b is connected to the transformer 21 via the low impedance booth 51 and the terminal 53 is sequentially switched to the coil a 1 , the coil a 2 , and the coil a 3 .
Similarly, the moving connection unit 46 includes an insulating base 46a, a connection electrode 46b, a motor 46c, and a screw-like member 46d. The connecting electrode 46b is disposed on the insulating base 46a. Since the insulating base 46a is screwed with the threaded member 46d, when the motor 46c rotates the threaded member 46d, the insulating base 46a moves in the direction of the arrow 46e. Therefore, the coil 33 in which the connecting electrode 46b is connected to the transformer 31 via the low impedance booth 52 and the terminal 54 is sequentially switched to the coil b 1 , the coil b 2 , and the coil b 3 . An arrow 47 indicates the direction of movement of the heat generation area at this time.
[0021]
In FIG. 4, the high-frequency power source 40, the switching of the a-side transformer 21, the switching of the b-side transformer 31, the switching of the a-side coil 23, the switching of the b-side coil 33, the currents of the coils a 1 , b 1 , a 2 , b 2 . Ip switching is displayed.
First, at the timing of start P 1, the a-side transformer 21 is turned on by the transformer switching device 41, the high-frequency current Ip is supplied from the high-frequency power supply 40 to the coil a 1 , and the induction heat generation region c 1 is formed in the work 10.
Next, the supply of high-frequency power from the high-frequency power source 40 is turned off at the timing of P 2 , the a-side transformer 21 of the transformer switching device 41 is turned off, the b-side transformer 31 is turned on, and then the high-frequency power from the high-frequency power source 40 is again turned on. The power supply is turned on, the current Ip is passed through the coil b 1 , and the induction heat generation region c 2 is formed in the work 10.
Then, at the timing of the middle of the P 3 that by applying a current Ip in the coil b 1, by moving the movable link unit 45 switches the coil connected to the transformer 21 from the coil a 1 to the coil a 2, a coil a 2 Wait for the current to turn on.
At the timing of P 4 , the supply of high-frequency power from the high-frequency power source 40 is turned off, the b-side transformer 31 of the transformer switching device 41 is turned off, the a-side transformer 21 is turned on, The supply is turned on, the current Ip is passed through the coil a 2 , and the induction heat generation region c 3 is formed in the work 10.
[0022]
Then, at a timing in the middle of P 5 are passing a current Ip in the coil a 2, by moving the movable link unit 46 switches the coil connected to the transformer 31 from the coil b 1 to the coil b 2, the coil b 2 Wait for the power to turn on.
At the timing of P 6 , the supply of high-frequency power from the high-frequency power supply 40 is turned off, the a-side transformer 21 of the transformer switching device 41 is turned off, the b-side transformer 31 is turned on, and then the supply of high-frequency power is turned on again. A current Ip is passed through b 2 to form an induction heat generation region c 4 in the workpiece 10.
By repeating the above switching up to the final induction heating coil, it is possible to move the induction heat generated by the high frequency with respect to the workpiece 10.
[0023]
FIG. 5 shows a coil switching method that can stabilize the movement of induction heat generation by the method of FIGS. 3 and 4 regardless of the material and shape of the workpiece 10.
In FIG. 5, when switching from the coil a 1 to the coil b 1 , the coil a 1 and the coil b 1 are alternately switched at a time T 3 that is shorter than the original energization time T 1 of the coil a 1 and the energization (energization time T 2 ) The original energization time of the coil b 1 is also T 1 . In this way, the coil a 1 and the coil b 1 are switched so that the current Ip flows.
At the switching timing of P 2 , the coil switching controller 42 controls on / off of the output of the high-frequency power supply 40 and the IGBTs 41 a to 41 d serving as switching elements of the transformer switching device 41, so that there is no hardware switching contact and high speed (cycle <1 Second), a stable high frequency output switching is realized, and a continuous pulse (on time T 2 , off time T 3 ) is passed through the a side coil 23 and the b side coil 33 to induce induction. Insufficient induction heat generation can be resolved at the boundary between c 1 and c 2 in the heat generation region. By adding this method to each switching timing in FIG. 4, it is possible to realize a stable movement of induction heat generation for any workpiece 10.
[0024]
With the above configuration, the plurality of induction heating coils 23 and 33 arranged in accordance with the heating part of the workpiece 10 induction-heats the workpiece 10. At that time, the plurality of induction heating coils 23 and 33 are connected to the high-frequency power source 40 that supplies current to the plurality of induction heating coils 23 and 33 via the changeover switches 22 and 32, respectively. , 33 is provided with a control unit (corresponding to the coil switching controller 42) of the changeover switches 22 and 32 (corresponding to the transformer switching device 41) for sequentially switching the currents to be passed through the plurality of induction heating coils 23. , 33 share the high-frequency power source 40 and perform switching control, so that the entire induction heating apparatus is reduced in size.
[0025]
Furthermore, the first transformer 21 and the second group induction heating coil 33 connectable to the first group induction heating coil 23 group, the second group induction heating coil 33 group, and the first group induction heating coil 23 group. And a second transformer 31 connectable to the group, the first group of induction heating coils 23 is energized through the first transformer 21 and the second group of induction heating coils 33 is secondly connected. Electricity can be passed through the transformer 31.
Further, since the first group of induction heating coils 23 and the second group of induction heating coils 33 are alternately arranged in accordance with the heating portion of the workpiece 10, the workpiece 10 is adjacent to each other in the first group of induction heating. The coil 23 and the second group induction heating coil 33 can be alternately heated.
[0026]
Furthermore, since the transformer switching means (corresponding to the transformer switching device 41) for switching the connection between the high-frequency power source 40 and the first and second groups of induction heating coils 23, 33 is provided, the transformer switching means. The connection between the high-frequency power supply 40 and the induction heating coils 23 and 33 of the first and second groups can be switched.
Furthermore, the moving connection means (which corresponds to the moving connecting units 45 and 46) for connecting the transformers 21 and 31 and the induction heating coils 23 and 33 and the movement control for controlling the movement of the moving connection means. Means (corresponding to the drive switching device 43) is provided, so that the induction heating coils 23 and 33 that generate heat are sequentially switched by the moving connection means, so that the induction heating device as a whole can be reduced in size and the work 10 can be made uniform. Heating becomes possible.
[0027]
Further, when the current is switched between the first group induction heating coil 23 and the second group induction heating coil 33, the induction heating coil energized before the current switching and the induction heating coil energized after the current switching; Therefore, the induction heat generation regions c 1 , c 2, and the like can be stably transferred from the induction heating coil before the current switching to the induction heating coil after the current switching.
Furthermore, the induction heating coils 23 and 33 of the first group and the second group are connected to the high-frequency power source 40 via the changeover switches 22 and 32, respectively, and are connected to the induction heating coils 23 and 33 of the first group and the second group. The currents to be flowed are sequentially switched, and when the currents of the adjacent induction heating coils 23 and 33 are switched, the induction heating coils 23 of the first group are at a time T 3 shorter than the original energization time T 1 of the induction heating coils 23 and 33. And the second group of induction heating coils 33 are alternately switched and energized, so that when the first induction heating coil 23 and the second induction heating coil 33 are switched, induction heat generation regions c 1 , c 2, etc. Can be stably transferred.
[0028]
【The invention's effect】
Since the induction heating device according to the first invention of the present application sequentially switches the coils that generate heat, the induction heating device can be downsized and the workpiece can be heated uniformly.
Furthermore, since a plurality of output transformers can be connected to one high-frequency power source, the cost of the induction heating device can be greatly reduced.
Furthermore , according to the induction heating method according to the second aspect of the present invention, it is possible to stably move the heat generation area of the workpiece when switching the induction heating coil.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an embodiment of the present invention.
FIG. 2 is an operation explanatory diagram of the embodiment.
FIG. 3 is a detailed circuit diagram of the embodiment.
4 is an operation explanatory diagram of what is shown in FIG. 3. FIG.
FIG. 5 is an explanatory diagram of a modification of the embodiment.
FIG. 6 is an explanatory diagram of a conventional example.
FIG. 7 is an explanatory diagram of another conventional example.
FIG. 8 is an operation explanatory diagram of a conventional example.
[Explanation of symbols]
10 Work 21, 31 Transformer 22, 32 Changeover switch 23, 33 Induction heating coil 40 High frequency power supply 41 Transformer switching device 42 Coil switching controller 43 Drive switching device 45, 46 Moving connection unit

Claims (2)

第１グループの誘導加熱コイル群と第２グループの誘導加熱コイル群と前記第１グループの誘導加熱コイル群に接続可能な第１トランス及び前記第２グループの誘導加熱コイル群に接続可能な第２トランスとを備え、A first transformer connectable to the induction heating coil group of the first group, the induction heating coil group of the second group, the induction heating coil group of the first group, and a second connectable to the induction heating coil group of the second group. With a transformer,
ワークの加熱部位に合わせて前記第１グループの誘導加熱コイルと前記第２グループの誘導加熱コイルを交互に配置し、  The first group of induction heating coils and the second group of induction heating coils are alternately arranged according to the heating part of the workpiece,
高周波電源と前記第１及び第２グループの誘導加熱コイル群との接続切換を行うトランス切換手段を設け、  A transformer switching means for switching connection between the high-frequency power source and the induction heating coil group of the first and second groups;
更に、前記各トランスと前記各誘導加熱コイルとを接続する移動型接続手段と該移動型接続手段の移動を制御する移動制御手段とを設けたことを特徴とする誘導加熱装置。  The induction heating apparatus further comprises moving connection means for connecting the transformers and the induction heating coils, and movement control means for controlling movement of the moving connection means. ワークの加熱部位に合わせて第１グループの誘導加熱コイルと第２グループの誘導加熱コイルを交互に配置し、The first group of induction heating coils and the second group of induction heating coils are alternately arranged according to the heating part of the workpiece,
高周波電源に前記第１グループ及び第２グループの誘導加熱コイルをそれぞれ切換スイッチを介して接続し、前記第１グループ及び第２グループの誘導加熱コイルに流す電流を順次切り換え、  The induction heating coils of the first group and the second group are connected to a high-frequency power source through switching switches, respectively, and the currents flowing through the induction heating coils of the first group and the second group are sequentially switched,
隣り合う前記誘導加熱コイルの電流切換に際して、該電流切換前に通電している前記誘導加熱コイルと該電流切換後に通電する前記誘導加熱コイルとの両方の通電を所定時間ラップさせることを特徴とする誘導加熱方法。  When switching the currents of the adjacent induction heating coils, the energization of both the induction heating coil energized before the current switching and the induction heating coil energized after the current switching is wrapped for a predetermined time. Induction heating method.
JP01417197A 1997-01-28 1997-01-28 Induction heating apparatus and method Expired - Fee Related JP3707181B2 (en)

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