JP2003250699A - Rice boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the heating amount to prevent boiling over by using the characteristic that after boiling is detected, heating of a lid heating means is cooled down by starch in an inner pot so that the temperature of the lid is hard to rise. <P>SOLUTION: This rice boiler is provided with a control means for controlling the application of an electric current to a heating means of a body 1 or a lid, and a temperature control means for controlling the current application of a lid heating means through a control means so that the temperature of the lid temperature sensor 6 reaches a preset temperature. The control means determines a temperature of the lid temperature sensor 6 higher than the fixed temperature at the start of boiling rice as boiling, and switches the preset temperature of the temperature control means 7 to a second preset temperature higher than the temperature T. In this rice boiler, boiling over preventing means is provided, whereby after switching to the second temperature by decision as boiling, the temperature of the lid temperature sensor 6 is determined at every fixed time, and when the temperature of the lid temperature sensor 6 does not rise above the predetermined temperature within a fixed time, it is determined that it is immediately before boiling over, and heating amount of the main heating means 4 is lowered temporarily or after that time on or temporarily stopped. <P>COPYRIGHT: (C)2003,JPO

Description

【発明の詳細な説明】 【０００１】 【発明の属する技術分野】本発明は、蒸気口からふきこ
ぼれを生じないでおいしいご飯を炊きあげる炊飯器に関
するものである。 【０００２】 【従来の技術】従来の炊飯器において、フタ温度センサ
ーによる温度制御によりフタからの加熱を行い、かつフ
タ温度センサーで沸騰の検出を行うものとして特許第２
８４４０１３号公報（以下従来技術１という）に示すも
のが知られている。 【０００３】その詳細は、フタ温度センサーの温度が第
一の温度になるようフタ加熱手段を制御し、フタ温度セ
ンサーが第一の温度より高い温度Ｔになったとき沸騰と
判断して加熱手段の火加減を切り替えるとともに、フタ
温度センサーの温度が温度Ｔより高い第二の温度になる
ようフタ加熱手段の制御を切り替えるものである。これ
により温度Ｔでの沸騰検出と、沸騰検出前の炊飯初期の
水温より高い第一の温度によるフタからの加熱及び沸騰
後の水温より高い第二の温度によるフタからの加熱を行
っている。 【０００４】一方、沸騰後に内釜内部で発生する、澱粉
質の溶けた粘性の高い湯（おねば）がフタの蒸気口から
泡となって噴出するのを防ぐため、フタの温度を上記従
来例の第二の温度に相当する沸騰点以上の高温に保つ技
術として特許第２７５０５６８号公報（以下従来技術２
という）に示すものが知られている。 【０００５】また、これに適したフタ加熱手段の配置と
して、おねばの泡がフタ内面に到達した時に、沸騰点以
上の高温としておくことで、触れた泡をはじけさせ、泡
を消滅させる技術（以下従来技術３という）も知られて
いる。 【０００６】さらに、このおねばが多量に発生してフタ
の熱が急激に奪われ、前記従来技術２及び３でふきこぼ
れが防げなくなった時、このフタの急激な温度低下をフ
タ温度センサーで検出してふきこぼれを防ぐ技術（以下
従来技術４という）も知られている。この技術はふきこ
ぼれそうな状況を検出し、内釜の加熱量を調整してふき
こぼれを防ぐものである。 【０００７】 【発明が解決しようとする課題】前記した従来技術のう
ち２〜４に示すものは、おねばが多量に発生する前に、
フタの温度を沸騰点以上の高温（第二の温度）に保って
おくことが必須である。特に、少量の炊飯時や誤って多
量に水加減してしまった場合など、沸騰し始めると一気
におねばが多量に発生する。 【０００８】また、フタ加熱手段でフタを沸騰点以上の
高温まで加熱するには、ある程度の時間を要することを
考慮すると、沸騰を開始する以前からフタの温度を高温
にしておくことが必要である。 【０００９】また、従来技術１に示すように、沸騰を温
度Ｔで検出してから第二の温度に切り替える方法では同
時に発生するおねばがフタに到達する以前に、フタの温
度を高温にすることは困難であった。 【００１０】このため、炊飯初期から高温で制御する必
要があり、前記従来例の技術による、第二の温度より低
いフタ温度センサーの温度Ｔで沸騰を検出する技術との
併用が不可能であった。 【００１１】また、上記従来技術の２〜４技術を使う場
合には、沸騰を検出せずに主加熱手段の火加減を制御す
るか、フタの温度に影響されない別の方法で沸騰を検出
する必要があった。 【００１２】 【課題を解決するための手段】かかる従来の問題を解決
するため、本発明では、本体と、本体に着脱自在に収納
される内釜と、本体に開閉自在に取り付けられ、内釜と
本体の上部を覆うフタと、内釜を加熱する主加熱手段
と、フタを加熱するフタ加熱手段と、フタの温度を検出
するフタ温度センサーとを備え、本体又はフタに主加熱
手段とフタ加熱手段への通電を制御する制御手段と、フ
タ温度センサーの温度が設定温度になるよう制御手段を
介してフタ加熱手段の通電を制御する温度調節手段を設
け、温度調節手段の設定温度は炊飯開始時には第一の設
定温度とし、フタ温度センサーが第一の設定温度より高
い温度Ｔに至った時、制御手段が沸騰と判断し、温度調
節手段の設定温度を温度Ｔより高く、沸騰温度より高い
第二の設定温度に切り替える炊飯器において、沸騰判断
で第二の温度に切り替わってからは一定時間毎にフタ温
度センサーの温度を判断し、一定時間内に予め定めた温
度以上にフタ温度センサーの温度が上昇していない場
合、ふきこぼれ直前と判断して主加熱手段の加熱量を一
時又はそれ以降低下もしくは一時停止するふきこぼれ防
止手段を設けたものである。 【００１３】上記本発明によれば、温度Ｔ以下の温度で
炊飯開始から沸騰までは第一の温度でフタの温度が制御
されるので、炊飯初期の水温が低い状況においてはフタ
からの加熱効果が得られる。また、内釜内が沸騰すると
フタが蒸気で加熱され、温度Ｔを超えて沸騰を判断で
き、これにより主加熱部の加熱量を調整するなど適切な
火加減が可能になる。また沸騰後は第二の温度に切り替
えてフタが高温に保たれるのでふきこぼれを防ぐ効果も
得られる。 【００１４】また、沸騰検出直後にはフタの温度が第二
の温度まで上がっておらず、一気におねばが発生した場
合は、おねばでフタ加熱手段の熱が奪われて第二の設定
温度まで上がることがない。従って従来ならふきこぼれ
が生じることになるが、本発明では沸騰判断で第二の温
度に切り替わってからは一定時間毎にフタ温度センサー
の温度を判断し、一定時間内に予め定めた温度以上にフ
タ温度センサーの温度が上昇していない場合には、ふき
こぼれ防止手段によりふきこぼれ直前と判断する。これ
によって、温度Ｔに至った以降におねばによりフタ加熱
手段の熱が奪われてフタの温度上昇が遅い場合には、お
ねばがフタまで到達していることを検出でき、主加熱手
段の加熱量を低下又は加熱を一時停止するので、ふきこ
ぼれを防止でき、また、この主加熱手段の加熱量の低下
でおねばが収まっている間にフタの温度を第二の温度ま
で上昇させる事が出来る。 【００１５】すなわち、本発明のふきこぼれ防止手段を
設けることによって上記した従来技術の効果のみを合わ
せて実施することができる。 【００１６】 【発明の実施の形態】以下、本発明の一実施例について
図面を用いて詳細に説明する。図１はふきこぼれが生じ
ない場合のフタ温度センサーの特性と主加熱手段への通
電状況を示す説明図。図２はふきこぼれが生じそうな場
合のフタ温度センサーの特性と主加熱手段への通電状況
を示す説明図。図３は本発明の炊飯器の断面図である。 【００１７】図中１は本体、２は内釜、３はフタ、４は
主加熱手段、５はフタ加熱手段、６はフタ温度センサ
ー、７は制御手段、８は温度調節手段、９はふきこぼれ
防止手段、１０はフタ３に設けた蒸気口である。 【００１８】その具体的構成は、本体１内に内釜２が着
脱自在に挿入され、フタ３は内釜１と本体２の上部を覆
う如く本体１に開閉自在に取り付けられている。 【００１９】本体１には内釜２を加熱する主加熱手段４
が設けられ、フタ３にはフタ３の内釜対向面を加熱する
フタ加熱手段５と、この近傍の温度を検出するフタ温度
センサー６が設けられている。 【００２０】また、本体１には主加熱手段４とフタ加熱
手段５への通電を制御する制御手段７と、フタ温度セン
サー６の温度が設定温度になるよう制御手段７を介して
フタ加熱手段５の通電を制御する温度調節手段８が設け
られている。温度調節手段８の設定温度は炊飯開始時に
は第一の設定温度として本実施例では６０℃と設定され
ている。なおこの制御手段７、温度調節手段８はフタ３
に設けても良い。 【００２１】フタ温度センサー６が第一の設定温度より
高い温度Ｔ（本実施例では８０℃）に至った時、制御手
段７が沸騰と判断し、温度調節手段８の設定温度を温度
Ｔより高く、沸騰温度より高い第二の設定温度、本実施
例では１２０℃に切り替える。 【００２２】制御手段７には、一定時間毎（本実施例で
は２０秒毎）にフタ温度センサー６の温度を判断し、一
定時間（２０秒）内に予め定めた温度（本実施例では５
℃）以上フタ温度センサー６の温度が上昇していない場
合、ふきこぼれ直前と判断して、主加熱手段４の加熱量
を低下もしくは加熱を一時停止するふきこぼれ防止手段
９を設けている。 【００２３】次にその作用について図１に従って炊飯の
動作を説明する。 【００２４】使用者が内釜２に適量の米と水を入れ、炊
飯スイッチ（図示せず）を操作すると、制御手段７が炊
飯の制御を開始する。制御手段７の制御により、主加熱
手段４が内釜２の加熱を開始するとともに、フタ加熱手
段５にも通電が開始される。以降、主加熱手段４は制御
手段７の炊飯プログラムに従い、いわゆる「始めチョロ
チョロ中パッパ…」の火加減制御がなされる。 【００２５】炊飯の開始時は温度調節手段８の制御温度
が第一の設定温度である６０℃に設定され、フタ温度セ
ンサー６の温度が第一の設定温度を超えると、フタ加熱
手段５への通電が停止され、第一の設定温度未満になる
と通電する動作を繰り返し、これによってフタ加熱手段
５の温度が略第一の設定温度に保たれる。このとき、内
釜２内部の水温は第一の設定温度より低いので、フタ３
から内釜２内に熱が移動し、フタ３からの加熱がなさ
れ、主加熱手段４による底からの加熱のみに比べ、均一
に加熱することができる。 【００２６】やがて、内釜２内部の水温が第一の設定温
度（６０℃）を超えると、フタ温度センサー６が第一の
設定温度を超えてフタ加熱手段５の通電を停止しても、
水温の上昇に従いフタ３の温度が下がることがなくな
り、フタ加熱手段５に通電していないにも関わらず、フ
タ温度センサー６の温度は徐々に上昇し始める。 【００２７】内釜２内が沸騰して蒸気が発生し始める
と、フタ温度センサー６の温度は急激に上昇し、温度Ｔ
（８０℃）を超えた時点で、制御手段７は沸騰と判断す
る。沸騰を判断した時点で、制御手段７は主加熱手段４
の電力を低下させる。これはいわゆる「グツグツ言う頃
火を引いて」の如き制御で、本実施例により沸騰を検出
する事により、正確なタイミングで火力を落とすことが
できる。 【００２８】同時に温度調節手段８の制御温度は第二の
設定温度（１２０℃）に切り替わり、フタ温度センサー
６はこの温度より低いためフタ加熱手段５に通電が開始
される。同時にふきこぼれ防止手段９が動作を開始す
る。ふきこぼれ防止手段９の動作は次の通りである。 【００２９】まず、その時のフタ温度センサー６の温度
が制御手段７に記憶される。２０秒経過すると、その時
のフタ温度センサー６の温度と、記憶している２０秒前
の温度の比較がなされ、予め定めた温度（５℃）以上温
度が上がっていれば、そのまま炊飯が継続される。次の
２０秒後の比較判断に備えて改めてその時のフタ温度セ
ンサー６の温度が記憶される。以降、２０秒毎にこの比
較がなされ、予め定めた温度（５℃）以上の温度上昇が
あれば炊飯が継続される。この状態は図１の状態であ
り、通常の炊飯はこの状態で動作する。 【００３０】ところが、炊飯の量が少ないときや、水加
減を多く誤った場合(図２)には、温度Ｔで沸騰を判断し
た直後に多量のおねばが発生する。このおねばの泡は蒸
気口１０まで到達してふきこぼれる前にフタ３に到達す
る。 【００３１】このため、沸騰で温度調節手段８の制御温
度が第二の設定温度に切り替えられてフタ加熱手段５に
通電されていてもフタ３に到達しているおねばに熱が奪
われ、フタ３の温度が上がらなくなる。（おねばの温度
である略１００℃にはなるものの、それ以上上がらなく
なる。） このとき、ふきこぼれ防止手段９の動作は２０秒前の記
憶温度と、そのときの温度の差が変化なく、５℃以上の
上昇をしなくなる。これにより、おねばがフタ３まで到
達して、ふきこぼれ直前の状況であると判断し、主加熱
手段４の加熱量を一時又はそれ以降低下もしくは一時停
止する。本実施例では、ふきこぼれ直前と判断した場合
は、２０秒間加熱を一時停止し、ふきこぼれを防ぐ構成
としている。２０秒経過すると再び元の加熱量に戻る
が、再びふきこぼれ防止手段９でふきこぼれ直前と判断
した場合は再び加熱の一時停止を行う。 【００３２】なお、ふきこぼれ防止手段９の動作はフタ
温度センサー６の温度が一定温度、例えば１１０℃を超
えた時点で終了させる。これは、フタ温度センサー６が
第二の設定温度（１２０℃）に至った後は、温度調節手
段８の働きにより第二の設定温度近傍でフタ温度センサ
ー６の温度が安定するため、このときにふきこぼれ防止
手段９で温度上昇せずと判断しないためである。 【００３３】 【発明の効果】以上説明したように、本発明によれば炊
飯開始から沸騰までの炊飯初期の水温が低い状況におい
ては、フタからの加熱効果が得られ、また、内釜内が沸
騰するとフタが蒸気で加熱され、それを温度センサーに
より正確に判断でき、これにより主加熱部の加熱量を調
整するなど適切な火加減が可能になる。また沸騰後はフ
タが高温に保たれるのでふきこぼれを防ぐ効果が得られ
る。 【００３４】また、沸騰検出直後に一気におねばが発生
した場合には、おねばでフタ加熱手段の熱が奪われてフ
タの温度が上がりにくくなり、これをふきこぼれ防止手
段でとらえて内釜の加熱量を減らし、ふきこぼれを防止
する。 【００３５】これにより、水加減が多いときのふきこぼ
れを防止できるので、沸騰後にふきこぼれを恐れて予め
加熱量を低くおさえる必要がなくなり、通常の炊飯時の
沸騰後の加熱量を高く設定でき、おいしいご飯を炊くこ
とができる。Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a rice cooker that cooks delicious rice without causing spillage from a steam port. 2. Description of the Related Art A conventional rice cooker is disclosed in Japanese Patent Application Laid-Open No. 2004-216, as an example in which heating from the lid is performed by temperature control by a lid temperature sensor and boiling is detected by the lid temperature sensor.
Japanese Unexamined Patent Publication No. 844013 (hereinafter referred to as prior art 1) is known. More specifically, the lid heating means is controlled so that the temperature of the lid temperature sensor becomes a first temperature, and when the temperature of the lid temperature sensor becomes higher than the first temperature T, it is determined that the boiling point is reached. And the control of the lid heating means is switched so that the temperature of the lid temperature sensor becomes the second temperature higher than the temperature T. Thereby, the detection of boiling at the temperature T, the heating from the lid at a first temperature higher than the water temperature at the beginning of cooking before the detection of boiling, and the heating from the lid at a second temperature higher than the water temperature after boiling are performed. On the other hand, in order to prevent the highly viscous hot water (neba) in which the starchy substance is generated inside the inner pot after boiling from blowing out from the steam port of the lid, the temperature of the lid is set to the above-mentioned value. Japanese Patent No. 2750568 (hereinafter referred to as “prior art 2”) discloses a technique for maintaining a temperature higher than the boiling point corresponding to the second temperature in the example.
Are known. [0005] In addition, as a suitable arrangement of the lid heating means, a technique is employed in which, when the foam of the ash reaches the inner surface of the lid, the temperature of the foam is raised to a temperature higher than the boiling point so that the touched foam is repelled and the foam disappears. (Hereinafter referred to as prior art 3) is also known. Further, when a large amount of this rice is generated and the heat of the lid is rapidly taken away and the spillover cannot be prevented in the above-mentioned prior arts 2 and 3, a rapid temperature drop of the lid is detected by a lid temperature sensor. There is also known a technique for preventing spills (hereinafter referred to as Conventional Technique 4). This technique detects a situation in which a spill is likely to occur, and adjusts the heating amount of the inner pot to prevent the spill. [0007] Among the above-mentioned prior arts, the ones shown in 2 to 4 are described in Japanese Patent Application Laid-Open No. H10-284,
It is essential to keep the temperature of the lid at a high temperature (second temperature) higher than the boiling point. Especially when a small amount of rice is cooked, or when a large amount of water is added by mistake, when boiling begins, a large amount of rice is generated at once. Considering that it takes a certain amount of time to heat the lid to a temperature higher than the boiling point by the lid heating means, it is necessary to keep the temperature of the lid high before the start of boiling. is there. Further, as shown in the prior art 1, in the method of detecting the boiling point at the temperature T and then switching to the second temperature, the temperature of the lid is raised to a high temperature before the simultaneously occurring bed ends reach the lid. It was difficult. For this reason, it is necessary to control at a high temperature from the beginning of rice cooking, and it cannot be used together with the technique of the prior art for detecting boiling at a temperature T of a lid temperature sensor lower than the second temperature. Was. Further, when the above-mentioned prior arts 2 to 4 are used, the degree of ignition of the main heating means is controlled without detecting the boiling, or the boiling is detected by another method which is not affected by the temperature of the lid. Needed. In order to solve the above-mentioned conventional problems, according to the present invention, a main body, an inner pot detachably housed in the main body, and an inner pot attached to the main body so as to be openable and closable are provided. And a lid for covering the upper part of the main body, a main heating means for heating the inner pot, a lid heating means for heating the lid, and a lid temperature sensor for detecting a temperature of the lid. Control means for controlling the energization of the heating means and temperature control means for controlling the energization of the lid heating means via the control means so that the temperature of the lid temperature sensor becomes the set temperature, wherein the set temperature of the temperature adjustment means is rice cooking At the start, the temperature is set to the first set temperature, and when the lid temperature sensor reaches a temperature T higher than the first set temperature, the control means judges that the temperature is boiling. High second In the rice cooker that switches to the set temperature, the temperature of the lid temperature sensor is judged at regular intervals after switching to the second temperature by boiling judgment, and the temperature of the lid temperature sensor rises above a predetermined temperature within a fixed time If not, a spill-over prevention means for judging immediately before the spill-over and temporarily reducing or temporarily stopping the heating amount of the main heating means is provided. According to the present invention, since the temperature of the lid is controlled at the first temperature from the start of rice cooking to the boiling at a temperature equal to or lower than the temperature T, the heating effect from the lid in a situation where the water temperature is low at the beginning of rice cooking. Is obtained. Further, when the inside of the inner kettle boils, the lid is heated by the steam, so that the boiling can be judged to exceed the temperature T, thereby making it possible to appropriately control the amount of heat by adjusting the heating amount of the main heating part. After the boiling, the temperature is switched to the second temperature, and the lid is kept at a high temperature. If the temperature of the lid does not rise to the second temperature immediately after the detection of boiling, and the need arises at once, the heat of the lid heating means is removed by the need and the second set temperature is reached. Never go up. Therefore, in the prior art, spillover may occur, but in the present invention, the temperature of the lid temperature sensor is determined at regular intervals after switching to the second temperature by boiling determination, and the lid is heated to a temperature equal to or higher than a predetermined temperature within a predetermined time. If the temperature of the temperature sensor has not risen, it is determined by the spillover prevention means that it is immediately before the spillover. Thus, when the temperature of the lid is slowly increased due to the loss of the heat of the lid heating means due to the need for the temperature after the temperature T has been reached, it is possible to detect that the rice reaches the lid, and the main heating means can be detected. Since the amount of heating is reduced or the heating is temporarily stopped, spillover can be prevented, and the temperature of the lid can be raised to the second temperature while the sleep is settled by the reduction in the amount of heating of the main heating means. I can do it. That is, by providing the spillover prevention means of the present invention, it is possible to carry out only the effects of the above-described prior art. An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing the characteristics of a lid temperature sensor and the state of energization to a main heating unit when spillover does not occur. FIG. 2 is an explanatory diagram showing the characteristics of the lid temperature sensor and the state of energization to the main heating means when spillover is likely to occur. FIG. 3 is a sectional view of the rice cooker of the present invention. In the figure, 1 is a main body, 2 is an inner pot, 3 is a lid, 4 is a main heating means, 5 is a lid heating means, 6 is a lid temperature sensor, 7 is a control means, 8 is a temperature adjusting means, and 9 is a spillover. The prevention means 10 is a steam port provided in the lid 3. As a specific configuration, an inner pot 2 is detachably inserted into the main body 1, and a lid 3 is attached to the main body 1 so as to be openable and closable so as to cover the inner pot 1 and the upper part of the main body 2. The main body 1 has a main heating means 4 for heating the inner pot 2.
The lid 3 is provided with a lid heating means 5 for heating the inner pot facing surface of the lid 3 and a lid temperature sensor 6 for detecting a temperature in the vicinity of the lid heating means 5. The main body 1 has a control means 7 for controlling the energization of the main heating means 4 and the lid heating means 5 and a lid heating means via the control means 7 for controlling the temperature of the lid temperature sensor 6 to the set temperature. 5 is provided with a temperature adjusting means 8 for controlling the current supply. In the present embodiment, the set temperature of the temperature adjusting means 8 is set to 60 ° C. as the first set temperature at the start of rice cooking. The control means 7 and the temperature adjusting means 8 are
May be provided. When the lid temperature sensor 6 reaches a temperature T (80 ° C. in the present embodiment) higher than the first set temperature, the control means 7 judges that the temperature is boiling, and the set temperature of the temperature control means 8 is changed from the temperature T. The second set temperature, which is higher than the boiling temperature, is switched to 120 ° C. in this embodiment. The control means 7 determines the temperature of the lid temperature sensor 6 at regular intervals (every 20 seconds in this embodiment) and determines a predetermined temperature (5 seconds in this embodiment) within a given time (20 seconds).
If the temperature of the lid temperature sensor 6 has not risen by more than (° C.), it is determined that the temperature is just before the spillover, and the spillover prevention means 9 for reducing the heating amount of the main heating means 4 or temporarily stopping the heating is provided. Next, the operation of rice cooking will be described with reference to FIG. When the user puts an appropriate amount of rice and water into the inner pot 2 and operates a rice cooker switch (not shown), the control means 7 starts controlling rice cooker. Under the control of the control means 7, the main heating means 4 starts heating the inner pot 2 and the lid heating means 5 is also energized. After that, the main heating means 4 controls the heating of the so-called “starting chorochoro middle wrapper...” According to the rice cooking program of the control means 7. At the start of rice cooking, the control temperature of the temperature adjusting means 8 is set to the first set temperature of 60 ° C., and when the temperature of the lid temperature sensor 6 exceeds the first set temperature, the lid heating means 5 is turned on. Is stopped, and when the temperature becomes lower than the first set temperature, the operation of energizing is repeated, whereby the temperature of the lid heating means 5 is maintained at substantially the first set temperature. At this time, since the water temperature inside the inner pot 2 is lower than the first set temperature, the lid 3
The heat moves from the inside to the inner pot 2, the heating from the lid 3 is performed, and the heating can be performed more uniformly than the heating from the bottom by the main heating means 4. When the water temperature inside the inner pot 2 exceeds the first set temperature (60 ° C.), the lid temperature sensor 6 will exceed the first set temperature and the energization of the lid heating means 5 will be stopped.
The temperature of the lid 3 does not decrease as the water temperature rises, and the temperature of the lid temperature sensor 6 starts to gradually increase even though the lid heating means 5 is not energized. When the inside of the inner pot 2 boils and the steam starts to be generated, the temperature of the lid temperature sensor 6 rises rapidly, and the temperature T
When the temperature exceeds (80 ° C.), the control means 7 determines that boiling has occurred. When the boiling is determined, the control means 7 controls the main heating means 4
Reduce the power of This is a control such as so-called "pull the fire when it is sloppy". By detecting the boiling according to the present embodiment, the heating power can be reduced at an accurate timing. At the same time, the control temperature of the temperature adjusting means 8 is switched to the second set temperature (120 ° C.). Since the temperature of the lid temperature sensor 6 is lower than this temperature, energization of the lid heating means 5 is started. At the same time, the spillover prevention means 9 starts operating. The operation of the spill-over prevention means 9 is as follows. First, the temperature of the lid temperature sensor 6 at that time is stored in the control means 7. After the elapse of 20 seconds, the temperature of the lid temperature sensor 6 at that time is compared with the stored temperature 20 seconds before. If the temperature is higher than a predetermined temperature (5 ° C.), rice cooking is continued. You. The temperature of the lid temperature sensor 6 at that time is stored again in preparation for comparison judgment after the next 20 seconds. Thereafter, this comparison is made every 20 seconds, and if there is a temperature rise above a predetermined temperature (5 ° C.), rice cooking is continued. This state is the state of FIG. 1 and normal rice cooking operates in this state. However, when the amount of cooked rice is small or when the amount of water addition and subtraction is erroneous (FIG. 2), a large amount of rice is generated immediately after the boiling is judged at the temperature T. The rice foam reaches the lid 3 before reaching the steam port 10 and spilling over. For this reason, even if the control temperature of the temperature adjusting means 8 is switched to the second set temperature by boiling and the lid heating means 5 is energized, the heat reaching the lid 3 is deprived of heat, The temperature of the lid 3 does not rise. (Although the temperature becomes approximately 100 ° C., which is the temperature of the cat, it does not rise any more.) At this time, the operation of the spill-over prevention means 9 is performed by the same method as that of the storage temperature 20 seconds ago and the temperature at that time. It does not rise above ℃. As a result, it is determined that the rice reaches the lid 3 and the situation is immediately before the spillover, and the amount of heating of the main heating means 4 is temporarily or subsequently reduced or stopped. In the present embodiment, when it is determined that the spillover occurs immediately, the heating is temporarily stopped for 20 seconds to prevent the spillover. After the elapse of 20 seconds, the heating amount returns to the original amount. However, when the spill-over prevention means 9 determines again that it is immediately before the spill-over, the heating is temporarily stopped again. The operation of the spill-over prevention means 9 is terminated when the temperature of the lid temperature sensor 6 exceeds a certain temperature, for example, 110 ° C. This is because after the temperature of the lid temperature sensor 6 reaches the second set temperature (120 ° C.), the temperature of the lid temperature sensor 6 is stabilized near the second set temperature by the operation of the temperature adjusting means 8. This is because it is not determined that the temperature does not rise by the spillover prevention means 9. As described above, according to the present invention, when the water temperature is low in the early stage of rice cooking from the start of rice cooking to boiling, the effect of heating from the lid can be obtained, and the inside of the inner pot can be heated. When boiling, the lid is heated by the steam, which can be accurately determined by the temperature sensor, thereby enabling appropriate heat control such as adjusting the heating amount of the main heating section. Further, after boiling, the lid is kept at a high temperature, so that an effect of preventing spilling can be obtained. In the case where the urethane is generated immediately after the boiling is detected, the heat of the lid heating means is deprived by the urethane, and the temperature of the lid is hardly increased. Reduce the amount of heating to prevent spills. [0035] With this, since it is possible to prevent the spilling when the water level is large, there is no need to reduce the amount of heating beforehand for fear of the spilling after boiling. You can cook rice.

【図面の簡単な説明】 【図１】本発明のふきこぼれが生じない場合のフタ温度
センサーの特性と主加熱手段への通電状況を示す説明
図。 【図２】同ふきこぼれが生じそうな場合のフタ温度セン
サーの特性と主加熱手段への通電状況を示す説明図。 【図３】本発明の炊飯器の断面図である。 【符号の説明】 １ 本体 ２ 内釜 ３ フタ ４ 主加熱手段 ５ フタ加熱手段 ６ フタ温度センサー ７ 制御手段 ８ 温度調節手段 ９ ふきこぼれ防止手段BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the characteristics of a lid temperature sensor and the state of energization to a main heating means when no spillover occurs according to the present invention. FIG. 2 is an explanatory diagram showing characteristics of a lid temperature sensor and a state of energization to a main heating unit when the spillover is likely to occur. FIG. 3 is a sectional view of the rice cooker of the present invention. [Description of Signs] 1 Main body 2 Inner pot 3 Lid 4 Main heating means 5 Lid heating means 6 Lid temperature sensor 7 Control means 8 Temperature adjusting means 9 Spillover prevention means

Claims (1)

【特許請求の範囲】 【請求項１】 本体（１）と、本体（１）内に着脱自在
に収納される内釜（２）と、本体（１）に開閉自在に取
り付けられ、内釜（２）と本体（１）の上部を覆うフタ
（３）と、内釜（２）を加熱する主加熱手段（４）と、
フタ（３）を加熱するフタ加熱手段（５）と、フタ
（３）の温度を検出するフタ温度センサー（６）とを備
え、本体（１）又はフタ（３）に主加熱手段（４）とフ
タ加熱手段（５）への通電を制御する制御手段（７）
と、フタ温度センサー（６）の温度が設定温度になるよ
う制御手段（７）を介してフタ加熱手段（５）の通電を
制御する温度調節手段（８）を設け、温度調節手段
（８）の設定温度は炊飯開始時には第一の設定温度と
し、フタ温度センサー（６）が第一の設定温度より高い
温度Ｔに至った時、制御手段（７）が沸騰と判断し、温
度調節手段（８）の設定温度を温度Ｔより高く、沸騰温
度より高い第二の設定温度に切り替える炊飯器におい
て、沸騰判断で第二の温度に切り替わってからは一定時
間毎にフタ温度センサー（６）の温度を判断し、一定時
間内に予め定めた温度以上にフタ温度センサー（６）の
温度が上昇していないとき、ふきこぼれ直前と判断して
主加熱手段（４）の加熱量を一時又はそれ以降低下もし
くは一時停止するふきこぼれ防止手段（９）を設けたこ
とを特徴とする炊飯器。Claims: 1. A main body (1), an inner pot (2) removably stored in the main body (1), and an inner pot (2) attached to the main body (1) so as to be openable and closable. 2) a lid (3) covering the upper part of the main body (1), a main heating means (4) for heating the inner pot (2),
A lid heating means (5) for heating the lid (3) and a lid temperature sensor (6) for detecting the temperature of the lid (3) are provided, and the main heating means (4) is provided on the main body (1) or the lid (3). Control means (7) for controlling the power supply to the heater and the lid heating means (5)
And a temperature adjusting means (8) for controlling energization of the lid heating means (5) via the control means (7) so that the temperature of the lid temperature sensor (6) becomes the set temperature. Is set to the first set temperature at the start of rice cooking, and when the lid temperature sensor (6) reaches a temperature T higher than the first set temperature, the control means (7) determines that boiling has occurred, and the temperature adjustment means ( In the rice cooker in which the set temperature of 8) is switched to the second set temperature higher than the temperature T and higher than the boiling temperature, the temperature of the lid temperature sensor (6) is periodically changed after switching to the second temperature by the boiling judgment. When the temperature of the lid temperature sensor (6) has not risen above a predetermined temperature within a predetermined time, it is determined that the temperature is just before the spillover, and the heating amount of the main heating means (4) is decreased temporarily or thereafter. Or a tentative pause Cooker, characterized in that a prevention means (9).