JP2005011618A

JP2005011618A - Induction heating cooking device

Info

Publication number: JP2005011618A
Application number: JP2003173172A
Authority: JP
Inventors: Hirofumi Inui; 弘文乾; Tomoya Fujinami; 知也藤濤; Katsunori Zaizen; 克徳財前
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-06-18
Filing date: 2003-06-18
Publication date: 2005-01-13
Anticipated expiration: 2023-06-18
Also published as: JP4393799B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooking device capable of surely preventing an excessive rise in temperature of a cooking container, in order to avoid damage on it due to empty heating or the like. <P>SOLUTION: The cooking device is provided with a top plate 22 to place a cooking container on, a heating control means 24 for drive control of a high-frequency current of a heating coil 23, a temperature detecting means 25 for detecting temperature of the cooking container 21 through the top plate 22, a heating volume setting means 26 for setting a heating volume for heating the cooking container 21, and an excessive temperature rise preventing means 27 for preventing an excessive temperature rise of the cooking container with the temperature detecting means 23 and the heating volume setting means 26. The excessive temperature rise preventing means 27 prevents the excessive temperature rise of the cooking container 21 by varying a comparative temperature of the excessive temperature rise preventing means 27 in accordance with the heating volume set by the heating volume setting means 26. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、一般家庭やオフィス、レストランなどで使用する誘導加熱調理器に関するものである。
【０００２】
【従来の技術】
従来、この種の誘導加熱調理器は、トッププレートの下面に温度検知手段を設けて、調理容器の底面温度を検出して加熱量を制御しているものである（例えば、特許文献１参照）。
【０００３】
この誘導加熱調理器の構造について図８を用いて説明する。
【０００４】
図に示すように、調理容器１が載置されるトッププレート２と、このトッププレート２の下方に配設された加熱コイル３と、前記トッププレート２の下方に配設された温度センサ４と、前記加熱コイル３に高周波電流を流して調理容器１を誘導加熱するインバータ回路５と、前記温度センサ４の検出温度が設定温度となるように前記インバータ回路５を駆動制御する制御手段６とを備えている。
【０００５】
ここで、図示していない電源、または操作スタートのスイッチが操作されて加熱が開始されると、制御手段６からの信号によりインバータ回路５が動作して、加熱コイル３から高周波磁界が発生される。この高周波磁界によって調理容器１が加熱され温度が上昇する。前記制御手段６は、加熱コイル３による加熱動作が開始されてから所定時間経過した時の前記温度センサ４の検出温度が設定温度よりも低い場合は、加熱出力を下げるか、または設定温度を低く変更するようにしている。これにより、加熱開始から所定時間経過後の温度センサ４の検出温度に応じて加熱量を制御して、調理容器１の温度が異常に上昇することを防止しているものである。
【０００６】
【特許文献１】
特開平１１−８７０４３号公報
【０００７】
【発明が解決しようとする課題】
しかしながら、前記従来の構成の誘導加熱調理器は、トッププレート２の熱伝導率の低さや熱容量の存在によって、温度センサ４の検出温度と調理容器１の温度に温度差が生じている。近年、誘導加熱調理器の加熱量は、ハイパワー化が進み、２．５ｋＷ〜３ｋＷ程度となり、前記温度差はより大きくなってきている。特に、少量の油の加熱時や被加熱物がない調理容器を加熱した場合、前記温度差は大きくなる傾向にあり、温度センサ４の応答性の低さから温度変化が検出できず、調理容器１の温度上昇の防止に遅れが生じて、調理容器１の空焼き状態など調理容器の傷みが生じやすいものである。
【０００８】
本発明は、前記従来の課題を解決するもので、加熱量が大きくなっても空焼き状態など調理容器の傷みがないよう、温度上昇をより確実に防止することができる誘導加熱調理器を提供することを目的とするものである。
【０００９】
【課題を解決するための手段】
前記目的を達成するために、本発明の誘導加熱調理器は、トッププレートを介して調理容器の温度を検出する温度検出手段と、調理容器の加熱量を設定する加熱量設定手段との出力により、調理容器の過昇温度を防止する過昇温度防止手段を備え、加熱量に応じて過昇温度防止手段の温度を可変して調理容器の過昇温度を防止するものである。
【００１０】
これにより、加熱量に応じて過昇温度を設定することができ、加熱量が大きくなっても空焼き状態など調理容器の傷みがないよう、調理容器の温度上昇をより確実に防止することができるものである。
【００１１】
【発明の実施の形態】
請求項１に記載の発明は、調理容器と、前記調理容器を載置するトッププレートと、前記トッププレートの下方に配置し前記調理容器を加熱する加熱コイルと、前記トッププレートを介して調理容器の温度を検出する温度検出手段と、前記調理容器を加熱する加熱量を設定する加熱量設定手段と、前記温度検出手段と前記加熱量設定手段との出力により調理容器の過昇温度を防止する過昇温度防止手段とを備え、加熱量に応じて過昇温度防止手段の温度を可変して調理容器の過昇温度を防止する誘導加熱調理器とすることにより、加熱量に応じて過昇温度を設定することができ、加熱量が大きくなっても空焼き状態など調理容器の傷みがないよう、調理容器の温度上昇をより確実に防止することができるものである。
【００１２】
請求項２に記載の発明は、調理容器から放射される放射温度を検出する赤外線センサからなる放射温度検出手段を備え、前記放射温度検出手段の温度情報により加熱量を制御する請求項１に記載の誘導加熱調理器とすることにより、調理容器の底面温度を正確に検知してより精度良く温度制御ができる。
【００１３】
請求項３に記載の発明は、加熱開始後、放射温度検出手段の温度情報を有効とする請求項２に記載の誘導加熱調理器とすることにより、調理容器が載置されない場合など外乱光の影響を低減して、調理容器の温度が正確に検出できる。
【００１４】
請求項４に記載の発明は、放射温度検出手段の温度微分値を算出する温度微分手段を設け、温度微分値が所定値以上の場合に加熱量を低下または停止させる請求項２または３に記載の誘導加熱調理器とすることにより、調理容器の急激な温度上昇を検出して加熱制御ができる。
【００１５】
請求項５に記載の発明は、温度微分手段は、放射温度検出手段の温度が略１００℃以上の場合に温度微分値を算出するようにして、温度微分値が所定値以上の場合に加熱量を低下または停止させる請求項４に記載の誘導加熱調理器とすることにより、調理容器の温度変化を正確に捉えることができる。
【００１６】
請求項６に記載の発明は、加熱開始から所定時間後に加熱を低下または停止させる加熱休止手段を設けた請求項１〜５のいずれか１項に記載の誘導加熱調理器とすることにより、正確に調理容器の温度が検知でき、より正確な温度制御ができる。
【００１７】
請求項７に記載の発明は、過昇温度防止手段は、加熱が開始されてから放射温度検出手段の温度が所定時間変化しない場合に異常を検出する異常検知手段を設け、放射温度検出手段が異常の場合に加熱量を低下または停止させるようにした請求項２〜６のいずれか１項に記載の誘導加熱調理器とすることにより、加熱量を抑制して調理容器の温度上昇を防止することができ、より安全性を高めることができる。
【００１８】
請求項８に記載の発明は、過昇温度防止手段は、温度検出手段と放射温度検出手段との温度情報差が所定値以上ある場合に放射温度検出手段の異常を検出する異常検知手段を設け、放射温度検出手段が異常の場合に加熱量を低下または停止させるようにした請求項２〜７のいずれか１項に記載の誘導加熱調理器とすることにより、調理容器の底面温度を抑制できるため、より安全を高めることができる。
【００１９】
【実施例】
以下、本発明の実施例について、図面を参照して説明する。
【００２０】
（実施例１）
図１は、本発明の実施例１における誘導加熱調理器の構成を示すものである。
【００２１】
本実施例の誘導加熱調理器は、被加熱物を収容し加熱する調理容器２１と、前記調理容器２１を載置するガラス材料などの非磁性体で構成したトッププレート２２と、前記トッププレート２の下方に配置し、調理容器２１を加熱するために誘導磁界を発生させる加熱コイル２３と、前記加熱コイル２３の高周波電流を駆動制御する加熱制御手段２４と、前記トッププレート２２を介して調理容器２１の温度を検出するサーミスタで構成した温度検出手段２５と、前記調理容器２１を加熱する加熱量を設定する操作スイッチからなる加熱量設定手段２６と、前記温度検出手段２３と前記加熱量設定手段２６との出力により調理容器２１の過昇温度を防止する過昇温度防止手段２７とを備えている。
【００２２】
前記過昇温度防止手段２７は、加熱設定手段２６で設定された加熱量に応じて過昇温度防止手段２７の比較温度を可変して調理容器２１の過昇温度を防止しているものである。
【００２３】
なお、前記温度検出手段２５は、トッププレート２２の下方位置で調理容器２１の載置部の中心部に設けているが、調理容器２１の温度が検出できればよく、本実施例の構成に限られるものではない。また、前記温度検出手段２５を複数個設けて、調理容器２１の温度を検出できる構成にすると、底面が反った形状の調理容器２１の温度検出が向上できるものである。
【００２４】
以下、本実施例の動作について説明する。図示していない電源を投入し、加熱量設定手段２６の操作スイッチで所定の加熱量を設定すると、加熱制御手段２４が加熱コイル２３に高周波電流を供給する。加熱コイル２３に高周波電流が供給されると、加熱コイル２３から誘導磁界が発せられ、トッププレート２２に載置された調理容器２１が誘導加熱される。この誘導加熱によって調理容器２１の温度が上昇し、調理容器２１内に収容された被加熱物が調理される。このとき、加熱制御手段２６は、温度検出手段２５からの温度情報によって、被加熱物の調理の進行状態を把握でき、調理の進行状態に応じて加熱コイル２３に供給する電力を調整するものである。こうして、調理容器２１内の被加熱物は調理されるものである。
【００２５】
過昇温度防止手段２７は、前記加熱量設定手段２６で設定された加熱量に応じて比較温度を定めている。例えば３ｋＷで加熱された場合では、略１２０℃で次の加熱量である２ｋＷに移行するようにしている。また、前記加熱量設定手段２６で設定された加熱量が２ｋＷの場合では、略１７５℃で次の加熱量である１．５ｋＷへ移行するようにしているものである。つまり、過昇温度防止手段２７は、加熱量が大きくなると比較する温度値を低くするようにして設定することで、調理容器２１の温度上昇が小さくできるようにしている。このように加熱量に応じて過昇温度防止手段２７の温度値を設けることにより、調理容器２１の温度上昇を抑制することができる。
【００２６】
なお、前記過昇温度防止手段２７の温度値は、高加熱量の場合に略１ｋＷまでの温度値にヒステリシス幅をもたせることで、より調理容器２１の温度上昇が低減できるものである。
【００２７】
以上のように本実施例によれば、過昇温度防止手段２７によって、加熱量に応じて比較する温度値を可変することで、高加熱量の場合でも調理容器２１の温度上昇が抑制できるもので、調理容器２１の高温加熱による痛みを防止することができる誘導加熱調理器が実現できるものである。
【００２８】
（実施例２）
続いて、図２により、本発明の実施例２における誘導加熱調理器について説明する。
【００２９】
本実施例において、実施例１との相違は、調理容器２１から放射される放射温度を検出する赤外線センサからなる放射温度検出手段２８を備え、この放射温度検出手段２８の温度情報により加熱量を制御するようにしたことである。
【００３０】
放射温度検出手段２８は、フォトダイオードからなる赤外線センサで構成し、調理容器２１の底面から放射される熱エネルギーを、トッププレート２２を透過させて検出し、その温度情報を過昇温度防止手段２７へ伝えている。
【００３１】
なお、前記放射温度検出手段２８は、焦電素子やサーモパイル等の赤外線を検出できるセンサが使用できるものであり、トッププレート２２に赤外線を透過させる透過材を設けても同様な温度検出ができる。
【００３２】
以下、本実施例の動作について説明する。放射温度検出手段２８は、調理容器２１の底面から放射される赤外線量を検出して温度を検知しているものである。このとき本実施例では、放射温度検出手段２８は、加熱コイル２３の中心部になるように取り付けられている。調理容器２１は、加熱コイル２２によって誘導加熱される。このときの温度分布は、加熱コイル２３の磁束の集中分布に比例するものである。加熱コイル２３の中心に対向する調理容器２１の中心部は、誘導加熱に直接影響されず、調理容器２１内の被加熱物の温度に比例するものである。この加熱コイル２３の中心となる調理容器２１の底面の温度を検出することで、正確に被加熱物の温度が検出できるものである。
【００３３】
また、放射温度検出手段２８は調理容器２１の底面を非接触に検知して、調理容器２１の温度を演算して求めているため、応答性が速く調理容器２１の温度を正確に検知することができるものである。このため、加熱制御手段２４の加熱コイル２３に対する電力制御も、調理容器２１の温度変化に即応したものとなっている。
【００３４】
以上のように本実施例によれば、放射温度検出手段２８によって、調理容器２１の底面の温度が検出できる構成としたものであり、調理容器２１の底面温度を正確に検知して温度制御ができる誘導加熱調理器を実現するものである。
【００３５】
（実施例３）
続いて、図３により、本発明の実施例３における誘導加熱調理器について説明する。
【００３６】
本実施例において、実施例２との相違は、調理容器２１がトッププレート２２上に載置されて加熱開始後、放射温度検出手段２８の温度情報を有効とするようにしたことである。
【００３７】
本実施例の動作について説明する。放射温度検出手段２８は、調理容器２１の底面に対向しているので、トッププレート２２上に調理容器２１が載置されていない場合は、太陽光や照明などの外乱光が入射されることになる。この外乱光の光エネルギーによって、放射温度検出手段２８は熱エネルギーがあるかのように出力することとなる。調理容器２１が載置されている場合は、調理容器２１の底面が対向すると共に、調理容器２１によって外乱光を遮断することができる。この状態では、調理容器２１の温度が検出できるものである。
【００３８】
また、調理容器有無検知手段２９が、加熱コイル２３の電流値や、パワー素子の電圧によって、調理容器２１の有無を検知し、その情報を過昇温度防止手段２７へ伝えている。調理容器２１がない場合は、加熱コイル２３の電流が小さく、これらを検出することで調理容器２１の載置状態が判別できる。加熱量設定手段２６によって、加熱が開始されても、調理容器２１の載置状態を判別して、より安定に調理容器２１の温度が検出できるものである。
【００３９】
以上のように本実施例によれば、調理容器２１がトッププレート２２上に載置されて加熱開始後、放射温度検出手段２８の温度情報を有効にするため、外乱光の影響を少なくして調理容器２１の温度が検出できる誘導加熱調理器を実現するものである。
【００４０】
（実施例４）
続いて、図４により、本発明の実施例４における誘導加熱調理器について説明する。
【００４１】
本実施例において、実施例２との相違は、放射温度検出手段２８の温度微分値を算出する温度微分手段３０を設け、温度微分値が所定値以上の場合に加熱量を低下または停止させるようにしていることである。
【００４２】
なお、温度微分手段３０は、移動平均処理を行って電気信号のノイズを減少させたり、微分値の温度変化幅を大きくしたりして検出精度を向上させることができるものである。
【００４３】
以下、本実施例の動作について説明する。放射温度検出手段２８は、調理容器２１の底面の温度を検出している。加熱が開始されると、調理容器２１の底面が誘導加熱され温度が上昇する。調理容器２１に被加熱物がある場合は、調理容器２１の底面の熱が被加熱物に伝達され、所定の温度になり調理ができるものである。また、調理容器２１に被加熱物がない場合、加熱が開始されると調理容器２１の底面の温度が急激に上昇する。これは被加熱物に熱が伝達しないためであり、調理容器２１の底面温度が急激に高温となる。放射温度検出手段２８は、この調理容器２１の底面温度の急激な温度上昇を検出し、加熱を低下または停止させるように加熱量を減少させているものである。
【００４４】
以上のように本実施例によれば、温度微分手段３０によって、調理容器２１の急激な温度上昇を検出して加熱量を抑制できるため、調理容器２１の温度上昇を防止することができる誘導加熱調理器を実現できるものである。
【００４５】
（実施例５）
続いて、図４により、本発明の実施例５における誘導加熱調理器について説明する。
【００４６】
本実施例において、実施例４との相違は、温度微分手段３０は、放射温度検出手段２８の温度が略１００℃以上の場合に温度微分値を算出するようにして、温度微分値が所定値以上の場合に加熱量を低下または停止させるようにしていることである。
【００４７】
以下、本実施例の動作を説明する。加熱が開始した直後、被加熱物があるにも関わらず、調理容器２１の底面が誘導加熱されると底面の温度が短時間に急激に上昇する現象が起こる。これは、高くなった調理容器２１底の熱が、被加熱物に伝達するのに時間が必要であるからである。特に、調理容器２１の底面が厚い場合に見られる現象であり、底面温度が略１００℃未満でありながら急激に温度が上昇するものである。本実施例では、前記現象と被加熱物がない時の温度上昇を区別するために、放射温度検出手段２８の温度が略１００℃以上の時に微分値を用いて、加熱量を制御するようにしている。
【００４８】
以上のように本実施例によれば、温度微分手段３０が、放射温度検出手段２８の略１００℃以上の時の温度変化を検出することによって、調理容器２１の温度変化を正確に捉えることができ、調理容器２１の温度上昇が防止できる誘導加熱調理器とすることができるものである。
【００４９】
（実施例６）
続いて、図５により、本発明の実施例６における誘導加熱調理器について説明する。
【００５０】
本実施例において、実施例１との相違は、加熱開始から所定時間後に加熱を低下または停止させる加熱休止手段３１を設けて、温度検知手段２５の検知温度の応答性を向上させるようにしたことである。
【００５１】
以下本実施例の動作について説明する。加熱量設定手段２６によって加熱量が設定されると、加熱が開始されると共に加熱休止手段３１に信号が送られる。加熱休止手段３１は、この信号を受け所定時間を計数した後に加熱量を停止させるように加熱量制御手段２４に信号を送る。そして、所定時間加熱を停止している間、調理容器２１の底面温度の熱が、トッププレート２２を介して温度検出手段２５に伝達されるものである。加熱休止手段３１が、所定時間を計数した後、再び加熱を開始するように加熱量制御手段２４に信号を送り、加熱が再び継続される。トッププレート２２は、熱伝導率が低く、調理容器２１の温度が温度検出手段２５に伝達するのに遅れが生じるものである。この伝達遅れを一時的に加熱を停止させることで、温度検出手段２５に調理容器２１の底面の熱を伝達させて、トッププレート２２による熱伝導の影響を少なくするものである。このように調理容器２１の温度を検出することで、調理容器２１の温度上昇を防止することができる。
【００５２】
以上のように本実施例によれば、加熱休止手段３１を設けることによって、正確に調理容器２１の温度が検知でき、より正確な温度制御が実行できるものである。
【００５３】
（実施例７）
続いて、図６により、本発明の実施例７における誘導加熱調理器について説明する。
【００５４】
本実施例において、実施例２との相違は、過昇温度防止手段２７は、加熱が開始されてから放射温度検出手段２８の温度が所定時間変化しない場合に異常を検出する異常検知手段３２を設け、放射温度検出手段２８が異常の場合に加熱量を低下または停止させるようにしたことである。
【００５５】
なお、異常検知手段３２によって、放射温度検出手段２８が異常である場合に、使用者に異常を報知させることも考えられる。
【００５６】
本実施例の動作について説明する。放射温度検出手段２８は、調理容器２１の底面温度を検出している。加熱が開始されると、調理容器２１の底面温度は上昇するものであり、この底面温度を検出している放射温度検出手段２８の温度値は、加熱開始時より変化している。しかし、放射温度検出手段２８の受光面が汚れたり、放射温度検出手段２８の温度検知素子が断線したりするなど故障していた場合は、放射温度検出手段２８の出力は変化しない。異常検知手段３２は、この放射温度検出手段２８の出力を監視して、加熱が継続されているのに出力が変化しないことで、放射温度検出手段２８が故障していると判断して、加熱量を低下あるいは停止させるようにしている。
【００５７】
以上のように本実施例では、異常検出手段３２が、放射温度検出手段２８の異常を検出することによって、加熱量を抑制して調理容器２１の温度上昇を防止することができ、より安全性を高めた誘導加熱調理器が実現できる。
【００５８】
（実施例８）
続いて、図７により、本発明の実施例８における誘導加熱調理器について説明する。
【００５９】
本実施例において、実施例２との相違は、過昇温度防止手段２７は、温度検出手段２５と放射温度検出手段２８との温度情報差が所定値以上ある場合に放射温度検出手段２８の異常を検出する異常検知手段３３を設け、放射温度検出手段２８が異常の場合に加熱量を低下または停止させるようにしたことである。
【００６０】
以下、本実施例の動作について説明する。加熱が開始されると、調理容器２１の温度が上昇して、温度検知手段２５が検出する温度は上昇する。また、放射温度検出手段２８が検出する温度も上昇する。加熱が継続されて、放射温度検出手段２８の温度値が少ししか変化しない場合は、放射温度検知手段２８の受光面が汚れている時、またトッププレート２２が汚れて調理容器２１の熱エネルギーが透過しない時であり、放射温度検出手段２８が正確に調理容器２１の底面温度が検出できていないことになる。また、調理容器２１が鏡面などの状態で放射率が極めて小さい場合、放射温度検出手段２８の出力変化は小さいものとなる。これらの出力が小さい場合は、放射温度検出手段２８が調理容器２１の底面温度を正確に検出できていないこととなり、加熱量を低下または停止させて安全性を高めるようにしている。
【００６１】
以上のように本実施例では、異常検知手段３３によって、調理容器２１の底面温度を抑制できるため、より安全を高めた誘導加熱調理器が実現できるものである。
【００６２】
【発明の効果】
以上のように、本発明の誘導加熱調理器は、加熱量に応じて過昇温度を設定することができ、加熱量が大きくなっても空焼き状態など調理容器の傷みがないよう、調理容器の温度上昇をより確実に防止することができるものである。
【図面の簡単な説明】
【図１】本発明の実施例１である誘導加熱調理器の構成を示す断面図
【図２】本発明の実施例２である誘導加熱調理器の構成を示す断面図
【図３】本発明の実施例３である誘導加熱調理器の構成を示す断面図
【図４】本発明の実施例４、５である誘導加熱調理器の構成を示す断面図
【図５】本発明の実施例６である誘導加熱調理器の構成を示す断面図
【図６】本発明の実施例７である誘導加熱調理器の構成を示す断面図
【図７】本発明の実施例８である誘導加熱調理器の構成を示す断面図
【図８】従来例である誘導加熱調理器の構成を示す断面図
【符号の説明】
２１調理容器
２２トッププレート
２３加熱コイル
２４加熱制御手段
２５温度検出手段
２６加熱量設定手段
２７過昇温度防止手段
２８放射温度検出手段
３０温度微分手段
３１加熱休止手段
３２、３３異常検知手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating cooker used in general homes, offices, restaurants and the like.
[0002]
[Prior art]
Conventionally, this type of induction heating cooker is provided with temperature detecting means on the lower surface of the top plate, and detects the bottom surface temperature of the cooking container to control the heating amount (see, for example, Patent Document 1). .
[0003]
The structure of this induction heating cooker will be described with reference to FIG.
[0004]
As shown in the figure, a top plate 2 on which a cooking container 1 is placed, a heating coil 3 disposed below the top plate 2, and a temperature sensor 4 disposed below the top plate 2. , An inverter circuit 5 for inductively heating the cooking vessel 1 by applying a high-frequency current to the heating coil 3, and a control means 6 for driving and controlling the inverter circuit 5 so that the temperature detected by the temperature sensor 4 becomes a set temperature. I have.
[0005]
Here, when heating is started by operating a power source (not shown) or an operation start switch, the inverter circuit 5 is operated by a signal from the control means 6 to generate a high frequency magnetic field from the heating coil 3. . The cooking vessel 1 is heated by this high frequency magnetic field and the temperature rises. When the temperature detected by the temperature sensor 4 is lower than a set temperature when a predetermined time has elapsed after the heating operation by the heating coil 3 is started, the control means 6 lowers the heating output or lowers the set temperature. I am trying to change it. Thereby, the amount of heating is controlled according to the temperature detected by the temperature sensor 4 after the elapse of a predetermined time from the start of heating, thereby preventing the temperature of the cooking container 1 from rising abnormally.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-87043
[Problems to be solved by the invention]
However, the induction heating cooker having the above-described conventional configuration has a temperature difference between the temperature detected by the temperature sensor 4 and the temperature of the cooking vessel 1 due to the low thermal conductivity of the top plate 2 and the presence of heat capacity. In recent years, the amount of heating of induction heating cookers has been increased to high power, and has become about 2.5 kW to 3 kW, and the temperature difference has become larger. In particular, when cooking a small amount of oil or when a cooking container without an object to be heated is heated, the temperature difference tends to increase, and the temperature change cannot be detected due to the low responsiveness of the temperature sensor 4, and the cooking container 1 is delayed, and the cooking container 1 is easily damaged, such as when the cooking container 1 is baked.
[0008]
The present invention solves the above-mentioned conventional problems, and provides an induction heating cooker that can more reliably prevent temperature rise so that there is no damage to the cooking container such as an empty baking state even when the amount of heating increases. It is intended to do.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an induction heating cooker according to the present invention includes an output from a temperature detection means for detecting the temperature of the cooking container via the top plate and a heating amount setting means for setting the heating amount of the cooking container. Further, an overheating temperature preventing means for preventing the cooking container from being overheated is provided, and the temperature of the overheating temperature prevention means is varied according to the amount of heating so as to prevent the overheating temperature of the cooking container.
[0010]
As a result, it is possible to set an excessive temperature according to the heating amount, and more reliably prevent the cooking vessel from rising in temperature so that the cooking vessel will not be damaged even if the heating amount is increased, such as an empty baking state. It can be done.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 is a cooking container, a top plate on which the cooking container is placed, a heating coil that is disposed below the top plate and heats the cooking container, and the cooking container through the top plate The temperature detection means for detecting the temperature of the cooking container, the heating amount setting means for setting the heating amount for heating the cooking container, and the output of the temperature detection means and the heating amount setting means prevent overheating temperature of the cooking container. An overheating temperature prevention means is provided, and an induction heating cooker that prevents the overheating temperature of the cooking container by varying the temperature of the overheating temperature prevention means according to the amount of heating is used to overheat according to the amount of heating. The temperature can be set, and even if the heating amount increases, the temperature rise of the cooking container can be more reliably prevented so that there is no damage to the cooking container such as an empty baking state.
[0012]
Invention of Claim 2 is equipped with the radiation temperature detection means which consists of an infrared sensor which detects the radiation temperature radiated | emitted from a cooking container, The heating amount is controlled by the temperature information of the said radiation temperature detection means. By using this induction heating cooker, it is possible to accurately detect the bottom surface temperature of the cooking container and control the temperature more accurately.
[0013]
The invention according to claim 3 makes the temperature information of the radiation temperature detecting means effective after the start of heating, and makes the induction heating cooker according to claim 2 to prevent disturbance light such as when the cooking container is not placed. The temperature of the cooking container can be accurately detected by reducing the influence.
[0014]
According to a fourth aspect of the present invention, there is provided a temperature differentiating means for calculating a temperature differential value of the radiation temperature detecting means, and the heating amount is reduced or stopped when the temperature differential value is a predetermined value or more. By using this induction heating cooker, it is possible to control the heating by detecting a rapid temperature rise of the cooking container.
[0015]
According to a fifth aspect of the present invention, the temperature differentiating means calculates the temperature differential value when the temperature of the radiation temperature detecting means is approximately 100 ° C. or higher, and the heating amount when the temperature differential value is equal to or higher than a predetermined value. By making it the induction heating cooking appliance of Claim 4 which reduces or stops, the temperature change of a cooking container can be caught correctly.
[0016]
The invention according to claim 6 is accurate by using the induction heating cooker according to any one of claims 1 to 5 provided with a heating pause means for reducing or stopping heating after a predetermined time from the start of heating. In addition, the temperature of the cooking container can be detected, and more accurate temperature control can be performed.
[0017]
According to a seventh aspect of the present invention, the overheated temperature preventing means includes an abnormality detecting means for detecting an abnormality when the temperature of the radiation temperature detecting means does not change for a predetermined time after the heating is started. The induction heating cooker according to any one of claims 2 to 6, wherein the heating amount is reduced or stopped in the case of an abnormality, thereby suppressing the heating amount and preventing the temperature of the cooking container from rising. It is possible to increase safety.
[0018]
According to an eighth aspect of the present invention, the overheating temperature preventing means includes an abnormality detecting means for detecting an abnormality of the radiation temperature detecting means when the temperature information difference between the temperature detecting means and the radiation temperature detecting means is a predetermined value or more. The bottom temperature of the cooking container can be suppressed by using the induction heating cooker according to any one of claims 2 to 7, wherein the amount of heating is reduced or stopped when the radiation temperature detection means is abnormal. Therefore, safety can be further improved.
[0019]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
(Example 1)
FIG. 1 shows the configuration of an induction heating cooker in Embodiment 1 of the present invention.
[0021]
The induction heating cooker of the present embodiment includes a cooking container 21 that houses and heats an object to be heated, a top plate 22 that is made of a nonmagnetic material such as a glass material on which the cooking container 21 is placed, and the top plate 2. A heating coil 23 that generates an induction magnetic field to heat the cooking vessel 21, heating control means 24 that drives and controls the high-frequency current of the heating coil 23, and the cooking vessel via the top plate 22. Temperature detecting means 25 constituted by a thermistor for detecting the temperature of 21, heating amount setting means 26 comprising an operation switch for setting the heating amount for heating the cooking vessel 21, the temperature detecting means 23 and the heating amount setting means 26 is provided with an excessively high temperature preventing means 27 for preventing the excessively elevated temperature of the cooking vessel 21 from being output.
[0022]
The overheating temperature preventing means 27 prevents the overheating temperature of the cooking vessel 21 by varying the comparison temperature of the overheating temperature preventing means 27 according to the heating amount set by the heating setting means 26. .
[0023]
In addition, although the said temperature detection means 25 is provided in the center part of the mounting part of the cooking vessel 21 in the downward position of the top plate 22, it should just be able to detect the temperature of the cooking vessel 21, and is restricted to the structure of a present Example. It is not a thing. In addition, when a plurality of the temperature detecting means 25 are provided so that the temperature of the cooking vessel 21 can be detected, the temperature detection of the cooking vessel 21 having a curved bottom surface can be improved.
[0024]
Hereinafter, the operation of this embodiment will be described. When a power supply (not shown) is turned on and a predetermined heating amount is set by the operation switch of the heating amount setting means 26, the heating control means 24 supplies a high frequency current to the heating coil 23. When a high frequency current is supplied to the heating coil 23, an induction magnetic field is generated from the heating coil 23, and the cooking vessel 21 placed on the top plate 22 is induction heated. Due to this induction heating, the temperature of the cooking container 21 rises, and the object to be heated contained in the cooking container 21 is cooked. At this time, the heating control means 26 can grasp the progress of cooking of the object to be heated by the temperature information from the temperature detection means 25, and adjusts the power supplied to the heating coil 23 according to the progress of cooking. is there. Thus, the object to be heated in the cooking container 21 is cooked.
[0025]
The excessive temperature preventing means 27 determines a comparison temperature according to the heating amount set by the heating amount setting means 26. For example, when heated at 3 kW, the next heating amount is shifted to 2 kW at about 120 ° C. Further, when the heating amount set by the heating amount setting means 26 is 2 kW, the next heating amount is shifted to 1.5 kW, which is approximately 175 ° C. In other words, the excessive temperature prevention means 27 is configured to reduce the temperature rise of the cooking container 21 by setting the temperature value to be compared to be lower when the heating amount is larger. Thus, the temperature rise of the cooking vessel 21 can be suppressed by providing the temperature value of the excessive temperature rise prevention means 27 according to the heating amount.
[0026]
In addition, the temperature value of the excessive temperature rise prevention means 27 can reduce the temperature rise of the cooking container 21 by giving a hysteresis width to the temperature value up to about 1 kW in the case of a high heating amount.
[0027]
As described above, according to the present embodiment, the temperature value to be compared can be varied according to the heating amount by the excessive temperature preventing means 27, so that the temperature rise of the cooking vessel 21 can be suppressed even in the case of a high heating amount. Thus, an induction heating cooker that can prevent pain due to high temperature heating of the cooking container 21 can be realized.
[0028]
(Example 2)
Then, the induction heating cooking appliance in Example 2 of this invention is demonstrated with FIG.
[0029]
In the present embodiment, the difference from the first embodiment is that radiation temperature detecting means 28 comprising an infrared sensor for detecting the radiation temperature radiated from the cooking container 21 is provided, and the amount of heating is determined by the temperature information of the radiation temperature detecting means 28. It is to control.
[0030]
The radiation temperature detection means 28 is constituted by an infrared sensor made of a photodiode, detects the thermal energy radiated from the bottom surface of the cooking vessel 21 through the top plate 22, and detects the temperature information of the overheated temperature prevention means 27. I tell you.
[0031]
The radiation temperature detecting means 28 can use a sensor capable of detecting infrared rays, such as a pyroelectric element or a thermopile, and the same temperature can be detected even if a transmission material that transmits infrared rays is provided on the top plate 22.
[0032]
Hereinafter, the operation of this embodiment will be described. The radiation temperature detecting means 28 detects the temperature by detecting the amount of infrared rays radiated from the bottom surface of the cooking vessel 21. At this time, in this embodiment, the radiation temperature detecting means 28 is attached so as to be the central portion of the heating coil 23. The cooking vessel 21 is induction heated by the heating coil 22. The temperature distribution at this time is proportional to the magnetic flux concentration distribution of the heating coil 23. The central portion of the cooking vessel 21 that faces the center of the heating coil 23 is not directly affected by induction heating, but is proportional to the temperature of the object to be heated in the cooking vessel 21. By detecting the temperature of the bottom surface of the cooking vessel 21 that is the center of the heating coil 23, the temperature of the object to be heated can be accurately detected.
[0033]
Further, since the radiation temperature detecting means 28 detects the bottom surface of the cooking container 21 in a non-contact manner and calculates the temperature of the cooking container 21, the responsiveness is fast and the temperature of the cooking container 21 is detected accurately. It is something that can be done. For this reason, the electric power control with respect to the heating coil 23 of the heating control means 24 is also adapted to the temperature change of the cooking vessel 21.
[0034]
As described above, according to this embodiment, the temperature of the bottom surface of the cooking vessel 21 can be detected by the radiation temperature detecting means 28, and the temperature control can be performed by accurately detecting the bottom surface temperature of the cooking vessel 21. An induction heating cooker that can be made is realized.
[0035]
Example 3
Next, an induction heating cooker in Embodiment 3 of the present invention will be described with reference to FIG.
[0036]
In the present embodiment, the difference from the second embodiment is that after the cooking container 21 is placed on the top plate 22 and heating is started, the temperature information of the radiation temperature detecting means 28 is made valid.
[0037]
The operation of this embodiment will be described. Since the radiation temperature detection means 28 is opposed to the bottom surface of the cooking vessel 21, disturbance light such as sunlight or illumination is incident when the cooking vessel 21 is not placed on the top plate 22. Become. Due to the light energy of the disturbance light, the radiation temperature detecting means 28 outputs as if there is thermal energy. When the cooking vessel 21 is placed, the bottom surface of the cooking vessel 21 is opposed, and disturbance light can be blocked by the cooking vessel 21. In this state, the temperature of the cooking vessel 21 can be detected.
[0038]
The cooking container presence / absence detection means 29 detects the presence / absence of the cooking container 21 based on the current value of the heating coil 23 and the voltage of the power element, and transmits the information to the overheated temperature prevention means 27. When there is no cooking container 21, the electric current of the heating coil 23 is small, and the mounting state of the cooking container 21 can be determined by detecting these. Even when heating is started by the heating amount setting means 26, the mounting state of the cooking vessel 21 can be determined and the temperature of the cooking vessel 21 can be detected more stably.
[0039]
As described above, according to the present embodiment, after the cooking vessel 21 is placed on the top plate 22 and heating is started, the temperature information of the radiation temperature detecting means 28 is made effective so that the influence of ambient light is reduced. An induction heating cooker that can detect the temperature of the cooking vessel 21 is realized.
[0040]
(Example 4)
Then, FIG. 4 demonstrates the induction heating cooking appliance in Example 4 of this invention.
[0041]
In this embodiment, the difference from the second embodiment is that a temperature differentiating means 30 for calculating the temperature differential value of the radiation temperature detecting means 28 is provided, and the heating amount is reduced or stopped when the temperature differential value is a predetermined value or more. It is to be.
[0042]
The temperature differentiating unit 30 can improve detection accuracy by performing a moving average process to reduce noise of an electric signal or to increase a temperature change width of a differential value.
[0043]
Hereinafter, the operation of this embodiment will be described. The radiation temperature detection means 28 detects the temperature of the bottom surface of the cooking vessel 21. When heating is started, the bottom surface of the cooking vessel 21 is induction-heated and the temperature rises. When there is an object to be heated in the cooking container 21, the heat of the bottom surface of the cooking container 21 is transmitted to the object to be heated, so that cooking can be performed at a predetermined temperature. Moreover, when there is no to-be-heated object in the cooking container 21, if heating is started, the temperature of the bottom face of the cooking container 21 will rise rapidly. This is because heat is not transmitted to the object to be heated, and the bottom surface temperature of the cooking vessel 21 rapidly increases. The radiation temperature detecting means 28 detects a rapid temperature rise in the bottom surface temperature of the cooking vessel 21 and reduces the heating amount so as to reduce or stop the heating.
[0044]
As described above, according to the present embodiment, the temperature differentiation means 30 can detect a rapid temperature rise of the cooking vessel 21 and suppress the amount of heating, so that the induction heating that can prevent the temperature rise of the cooking vessel 21 can be prevented. A cooker can be realized.
[0045]
(Example 5)
Then, the induction heating cooking appliance in Example 5 of this invention is demonstrated with FIG.
[0046]
In this embodiment, the difference from the fourth embodiment is that the temperature differential means 30 calculates the temperature differential value when the temperature of the radiation temperature detection means 28 is approximately 100 ° C. or higher, and the temperature differential value is a predetermined value. In this case, the heating amount is reduced or stopped.
[0047]
The operation of this embodiment will be described below. Immediately after the start of heating, there is a phenomenon in which the temperature of the bottom surface rapidly rises in a short time when the bottom surface of the cooking vessel 21 is induction-heated despite the presence of an object to be heated. This is because it takes time for the heat at the bottom of the cooking vessel 21 that has been raised to be transferred to the object to be heated. In particular, this phenomenon is observed when the bottom surface of the cooking vessel 21 is thick, and the temperature rapidly increases while the bottom surface temperature is less than about 100 ° C. In this embodiment, in order to distinguish the phenomenon from the temperature rise when there is no object to be heated, the amount of heating is controlled using a differential value when the temperature of the radiation temperature detecting means 28 is approximately 100 ° C. or higher. ing.
[0048]
As described above, according to the present embodiment, the temperature differentiating means 30 can accurately detect the temperature change of the cooking container 21 by detecting the temperature change when the radiation temperature detecting means 28 is approximately 100 ° C. or higher. It is possible to provide an induction heating cooker that can prevent the temperature rise of the cooking vessel 21.
[0049]
(Example 6)
Then, the induction heating cooking appliance in Example 6 of this invention is demonstrated with FIG.
[0050]
In this embodiment, the difference from the first embodiment is that a heating pause means 31 is provided to lower or stop the heating after a predetermined time from the start of heating so as to improve the responsiveness of the detected temperature of the temperature detecting means 25. It is.
[0051]
The operation of this embodiment will be described below. When the heating amount is set by the heating amount setting means 26, heating is started and a signal is sent to the heating pause means 31. The heating pause means 31 sends a signal to the heating amount control means 24 so as to stop the heating amount after receiving this signal and counting a predetermined time. And while heating is stopped for a predetermined time, the heat of the bottom surface temperature of the cooking vessel 21 is transmitted to the temperature detection means 25 via the top plate 22. After the heating pause means 31 counts a predetermined time, a signal is sent to the heating amount control means 24 so as to start heating again, and heating is continued again. The top plate 22 has a low thermal conductivity, and a delay occurs when the temperature of the cooking vessel 21 is transmitted to the temperature detecting means 25. By temporarily stopping the heating for this transmission delay, the heat of the bottom surface of the cooking vessel 21 is transmitted to the temperature detecting means 25, and the influence of heat conduction by the top plate 22 is reduced. Thus, the temperature rise of the cooking container 21 can be prevented by detecting the temperature of the cooking container 21.
[0052]
As described above, according to the present embodiment, by providing the heating pause means 31, the temperature of the cooking vessel 21 can be accurately detected, and more accurate temperature control can be performed.
[0053]
(Example 7)
Then, the induction heating cooking appliance in Example 7 of this invention is demonstrated with FIG.
[0054]
In the present embodiment, the difference from the second embodiment is that the overheating temperature preventing means 27 includes an abnormality detecting means 32 for detecting an abnormality when the temperature of the radiation temperature detecting means 28 does not change for a predetermined time after heating is started. The amount of heating is reduced or stopped when the radiation temperature detecting means 28 is abnormal.
[0055]
In addition, when the radiation temperature detection means 28 is abnormal by the abnormality detection means 32, it is also conceivable to notify the user of the abnormality.
[0056]
The operation of this embodiment will be described. The radiation temperature detection means 28 detects the bottom surface temperature of the cooking vessel 21. When heating is started, the bottom surface temperature of the cooking vessel 21 rises, and the temperature value of the radiation temperature detecting means 28 that detects this bottom surface temperature has changed since the start of heating. However, if the light receiving surface of the radiation temperature detecting means 28 is dirty or the temperature detecting element of the radiation temperature detecting means 28 is broken, the output of the radiation temperature detecting means 28 does not change. The abnormality detection means 32 monitors the output of the radiation temperature detection means 28 and determines that the radiation temperature detection means 28 is out of order because the output does not change even though the heating is continued. The amount is reduced or stopped.
[0057]
As described above, in the present embodiment, the abnormality detection unit 32 detects the abnormality of the radiation temperature detection unit 28, thereby suppressing the amount of heating and preventing the temperature of the cooking container 21 from increasing. An induction heating cooker with a high level of heat can be realized.
[0058]
(Example 8)
Then, the induction heating cooking appliance in Example 8 of this invention is demonstrated with FIG.
[0059]
In this embodiment, the difference from the second embodiment is that the excessive temperature prevention means 27 is different from the temperature detection means 25 and the radiation temperature detection means 28 when the temperature information difference between the temperature detection means 25 and the radiation temperature detection means 28 exceeds a predetermined value. Is provided, and when the radiation temperature detecting means 28 is abnormal, the heating amount is reduced or stopped.
[0060]
Hereinafter, the operation of this embodiment will be described. When heating is started, the temperature of the cooking vessel 21 rises, and the temperature detected by the temperature detection means 25 rises. Further, the temperature detected by the radiation temperature detecting means 28 also increases. When heating is continued and the temperature value of the radiation temperature detecting means 28 changes only slightly, when the light receiving surface of the radiation temperature detecting means 28 is dirty, or when the top plate 22 is dirty and the thermal energy of the cooking vessel 21 is increased. This is a time when light does not pass through, and the radiation temperature detecting means 28 has not been able to accurately detect the bottom surface temperature of the cooking vessel 21. In addition, when the emissivity is extremely small when the cooking vessel 21 is in a mirror surface or the like, the output change of the radiation temperature detecting means 28 is small. When these outputs are small, the radiation temperature detecting means 28 cannot accurately detect the bottom surface temperature of the cooking vessel 21, and the heating amount is reduced or stopped to increase safety.
[0061]
As described above, in the present embodiment, since the bottom surface temperature of the cooking container 21 can be suppressed by the abnormality detection means 33, an induction heating cooker with higher safety can be realized.
[0062]
【The invention's effect】
As described above, the induction heating cooker of the present invention can set an excessive temperature according to the amount of heating, and even if the amount of heating increases, the cooking container does not damage the cooking container such as an empty baking state. The temperature rise can be prevented more reliably.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the configuration of an induction heating cooker that is Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing the configuration of an induction heating cooker that is Embodiment 2 of the present invention. FIG. 4 is a cross-sectional view showing the configuration of an induction heating cooker that is Embodiment 3 of the present invention. FIG. 4 is a cross-sectional view showing the configuration of an induction heating cooker that is Embodiments 4 and 5 of the present invention. FIG. 6 is a cross-sectional view showing the configuration of an induction heating cooker that is Embodiment 7 of the present invention. FIG. 7 is a cross-sectional view showing the configuration of an induction heating cooker that is Embodiment 7 of the present invention. FIG. 8 is a cross-sectional view showing the structure of a conventional induction heating cooker.
DESCRIPTION OF SYMBOLS 21 Cooking container 22 Top plate 23 Heating coil 24 Heating control means 25 Temperature detection means 26 Heating amount setting means 27 Excessive temperature prevention means 28 Radiation temperature detection means 30 Temperature differentiation means 31 Heating suspension means 32, 33 Abnormality detection means

Claims

A cooking container; a top plate on which the cooking container is placed; a heating coil that is disposed below the top plate and that heats the cooking container; and a temperature detection means that detects the temperature of the cooking container via the top plate; A heating amount setting means for setting a heating amount for heating the cooking container; and an overheating temperature preventing means for preventing an overheating temperature of the cooking container by outputs of the temperature detection means and the heating amount setting means, An induction heating cooker that prevents the overheating temperature of the cooking container by changing the temperature of the overheating temperature preventing means according to the amount of heating.

The induction heating cooker according to claim 1, further comprising radiation temperature detection means comprising an infrared sensor for detecting radiation temperature radiated from the cooking container, wherein the amount of heating is controlled by temperature information of the radiation temperature detection means.

The induction heating cooker according to claim 2, wherein the temperature information of the radiation temperature detecting means is validated after the heating is started.

The induction heating cooker according to claim 2 or 3, wherein a temperature differentiating means for calculating a temperature differential value of the radiation temperature detecting means is provided, and the heating amount is reduced or stopped when the temperature differential value is a predetermined value or more.

The temperature differentiating means calculates the temperature differential value when the temperature of the radiation temperature detecting means is approximately 100 ° C. or higher, and reduces or stops the heating amount when the temperature differential value is equal to or higher than a predetermined value. The induction heating cooker described.

The induction heating cooker according to any one of claims 1 to 5, further comprising a heating pause unit that reduces or stops heating after a predetermined time from the start of heating.

The overheating temperature preventing means includes an abnormality detecting means for detecting an abnormality when the temperature of the radiation temperature detecting means does not change for a predetermined time after heating is started, and when the radiation temperature detecting means is abnormal, the heating amount is reduced or The induction heating cooker according to any one of claims 2 to 6, wherein the induction heating cooker is stopped.

The overheating temperature preventing means includes an abnormality detecting means for detecting an abnormality of the radiation temperature detecting means when the temperature information difference between the temperature detecting means and the radiation temperature detecting means is equal to or greater than a predetermined value, and when the radiation temperature detecting means is abnormal. The induction heating cooker according to any one of claims 2 to 7, wherein the heating amount is reduced or stopped.