JP2008054978A - Electric rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker which can control heating without being affected by low thermal conductivity and deteriorating quality of rice during warming rice after cooking in nonmetallic pot, and can warm cooked rice in energy saving mode taking advantage of the efficiency of thermal storage and warming property of the pot, without any problem such as dew condensation. <P>SOLUTION: The rice cooker has a bottom heat source 4 on the side of the main body 2 storing the nonmetallic pot 1, a side heat source 5 and a lid heat source 6 on the side of the lid member 3 to close the pot. The rice cooker cooks rice and warms the cooked rice from the temperature information from the main sensor 34 to detect the temperature of the bottom of the pot 1, the side sub sensor 121 with the side heat source 5, and the lid sub sensor 123 with lid heat source 6. Especially in the keeping warm mode, the lid heat source 6 is operated according to the set value of the lid sensor 123, the side heat source 5 is operated according to the set value of the side sub sensor 121, and the bottom heat source 4 and the side heat source 5 are operated according to the set value of the main sensor 34 to control keeping warm and heating and to achieve the above purpose. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention heats the body of the pan on the bottom side heating source, which heats the bottom of the pan made of a non-metallic material such as a clay pot by means of an alternating magnetic field from a heating coil on the body side housing the pan. It is related with the electric rice cooker which is provided with the side heating source provided in this way, the lid heating source provided in the lid body side which closes a pot, and cooks rice or heat-retains based on the temperature information at the time of heating.

  It is known that cooking can be performed by providing a heating element that generates heat by electromagnetic induction in a clay pot (see, for example, Patent Documents 1 and 2). A rice cooker that cooks rice with a simple heating source is already known (see, for example, Patent Document 3). Even if there is a difference between the outer surface and the outer surface of the clay pots described in Patent Documents 1 and 2, a heating layer is provided at the bottom or near the bottom, and heat is generated by electromagnetic induction from an electromagnetic induction cooker and heated from the bottom for cooking. Like to do. The thing of patent document 3 provides the magnetic heating element in the outer surface of the bottom part of a clay pot, and it is made to heat-induced by magnetic coupling with the alternating magnetic field from a heating coil, and is made to cook rice.

Non-metal pots represented by such clay pots have low thermal conductivity, and clay pots are as small as 1/200 of aluminum, and are thick, so they have good heat storage properties and are easy to heat up. When it is used alone as described in Patent Documents 1 to 3, it is easy to cook rice deliciously.
JP 2005-334351 A Utility Model Registration No. 3110038 JP-A-2005-413

  By the way, uniform heating and timely temperature change are important conditions for cooking delicious rice. In addition, if there is a partial temperature difference when the cooked rice is kept warm, dew condensation occurs, causing the rice to become sticky or whiten, so uniform heating is important. In the rice cooking and heat insulation area made by a metal pan and the inner lid that closes it, temperature information with good correlation is obtained by a temperature sensor that makes contact with the outside using the heat conductivity of the pan and lid. As a result, proper temperature control can be performed.

  On the other hand, when a non-metallic pan is adopted for an electric rice cooker, temperature information of the rice cooking / heat-retaining area is difficult to detect with good correlation as in the case of a metallic pan because of its low thermal conductivity. For example, in the case of the main sensor that comes into contact with the bottom of the pan from the main body side, the correlation with the rice cooking temperature and rice temperature in the pan is high, and based on this, timer control based on experience from a predetermined target temperature point The present applicant realizes that rice is cooked deliciously in combination.

  On the other hand, with regard to the heat control of rice, the opening and lid side of non-metallic pots are easily affected by outside air, and the temperature difference between the surface and the bottom of the rice is large. However, it is difficult to control the heating so as to compensate for such a temperature difference. The present inventor conducted a heat insulation experiment for 3 hours by using a technique that does not use a bottom heating source in order to prevent scorching at the bottom. As a result, when the amount of cooking rice is large, Although some dew is observed on the inner surface, other than that on the inner surface of the inner lid, dew is not recognized on the inner surface of the pan opening, but on the surface of the rice, white blurring is recognized in the surrounding local area when the maximum amount of rice is cooked. In the case of the amount of intermediate rice cooking, it was slightly dry, and in the case of the minimum amount of rice cooking, no problem was found. However, it was also found that the minimum rice cooking temperature lowered the temperature to about 65 ° C., approaching the breeding temperature range of miscellaneous bacteria, and this was a problem.

  Specifically, the experiment is for 100 sizes with a maximum cooked rice size of 5.5 go and 150 sizes with a maximum cooked rice size of 8 go, for each of the maximum cooked rice amount, the intermediate cooked rice amount, and the minimum cooked rice amount. In the case of 150 size, the thermocouple distributed according to the difference in the amount of rice cooking shown in FIGS. 13 (a) to (c). The temperature of the rice was detected by the pair. In addition, for detection, after the rice was cooked, the rice was stuck to the inner surface of the pan, and after 5 minutes of cooking, the rice was stirred and a thermocouple was inserted. Subsequently, it was kept warm for 3 hours in a room temperature range of 28-30 ° C. without air conditioning.

  The result was as shown in Table 1 below in the case of 100 sizes.

また、１５０サイズの場合では下記の表２に示す通りであった。

In the case of 150 size, it was as shown in Table 2 below.

いずれの場合も、底部加熱が不足しているし、最小炊飯量では保温温度が不足気味になっているといえる。そこで本発明者は、このような問題に対応するのに、種々に実験を行い検討を重ねた結果、場合により側部加熱源、蓋加熱源に加え、底部加熱源をも利用して保温加熱制御を行い、かつこの保温加熱制御を主センサに加え、側部センサ、蓋センサからの３つの温度情報を基にある条件を満足して実行することにより対応できることを知見した。

In any case, it can be said that the bottom heating is insufficient, and the minimum temperature is not sufficient for the heat retention temperature. Therefore, the present inventor has conducted various experiments and studies to cope with such problems, and as a result, in some cases, the bottom heating source is used in addition to the side heating source and the lid heating source. It has been found that it is possible to respond by performing control and satisfying certain conditions based on the three temperature information from the side sensor and the lid sensor by adding this heat insulation heating control to the main sensor.

  In addition, in the technical development for practical use of such an electric rice cooker, the inventor of the present invention has an electrical heat retention from the high heat storage and heat retention properties of the non-metallic pan to heat the cooked rice. While paying attention to the fact that it is possible to maintain a temperature of around 70 degrees in 3 hours without control, and a mode in which heat control after cooking is omitted even between users and families with a slight variation in meal time, It has also been found that in the natural temperature drop of rice after cooking in a non-metallic pan, condensation is likely to occur in the rice storage area and the quality of the rice is impaired. Such a tendency is also seen in the relationship between a non-metallic pan and a non-metallic lid. The pan side contains rice serving as a heat source deeply and is difficult to cool, whereas the lid side This is due to the fact that there is a space between the rice and rice, and it is easy to cool down under the influence of outside air temperature.

  The purpose of the present invention is based on such new knowledge, and adopts a non-metallic pan such as a clay pot to realize a heat retention mode, and can achieve heat insulation heating control under appropriate temperature control. In addition, heat insulation heating control is not performed until a predetermined time from rice cooking, and energy saving is achieved, and the problem of condensation due to a temperature difference occurring while heat insulation heating control is not performed is solved. .

  In order to achieve the above object, the electric rice cooker of the present invention is a bottom heating source that induces heat generation by an alternating magnetic field from a heating coil on the main body side that accommodates the pan in the non-metallic pan bottom heating element. A side heating source provided to heat the body of the pan on the main body side, a lid heating source provided on the lid side closing the pan, and a main sensor provided on the main body side to detect the temperature of the bottom of the pan An electric rice cooker that performs rice cooking or heat insulation with a side auxiliary sensor provided on the main body side together with the side heating source, and a lid auxiliary sensor provided on the lid body side together with the lid heating source, The lid heating source is responsive to the set value of the sub sensor, the side heating source is responsive to the set value of the side sub sensor, and the bottom heating source and the side heating source are set to the set value of the main sensor. It is characterized by performing heat insulation heating control by reacting.

  In such a configuration, using the high correlation with the temperature of the rice of the main sensor, in order to lead the heat insulation heating control, the bottom heating source and the side heating source with respect to the set value of the main sensor In response to the temperature relationship between the bottom of the pan and the torso, keeping the overall temperature of the pan and rice at the target temperature without any temperature difference, there is no scorch and the rice is not sticky. While ensuring the minimum temperature compensation for the bottom, the side heating source for the set value of the side sub sensor can be used to prevent temperature deviation due to excessive or insufficient response of the side heating source to the set value of the main sensor or the influence of outside air temperature. The temperature compensation at the lid portion that reflects the result of the influence of the external air temperature can be ensured by the response of the lid heating sensor to the set value of the lid sub sensor.

  Here, such heat insulation heating control is based on the three temperature information from the lid sub sensor, the side sub sensor, and the main sensor, and the heat insulation heating that maintains the temperature balance of the whole rice storage area and therefore the whole pan and rice. It can be said that it is control, and that is the best.

There are three side heating sources, an upper stage, a middle stage, and a lower stage. The lid heating source, the side heating source upper stage, the side heating source middle stage and the lower stage are less than or equal to the set value of the main sensor for the target temperature. In the further configuration in which the heat insulation heating control is performed by changing the energization capacity in three units of
The energization ratio is changed in three units: the lid heating source, the upper side heating source, the middle side heating source, and the lower heating stage, depending on whether or not the set value corresponds to a certain target temperature of the main sensor. The temperature compensation in the thermal insulation heating control of the heat source extends to the lid heating source, and the side heating source is divided into the upper stage, the middle stage and the lower stage with independent energization rate changes. It becomes easier to finely and uniformly perform overheat insulation control for the whole.

In a further configuration that performs heat insulation heating control at a predetermined time from cooking rice,
Except until a predetermined point in time, such as when an appropriate heat retention temperature of 70 ° C. can be secured, the heat retention heating control is performed thereafter, so that wasteful heat retention heating control is eliminated.

From the cooked rice to a predetermined time point, in the further configuration to perform the condensation control for preventing condensation in the rice storage area,
With natural heat insulation that takes advantage of the heat retention of non-metallic pots by performing condensation control that prevents or suppresses condensation in the rice storage area during natural temperature drop from cooking to thermal insulation heating control Condensing with a small amount of power consumption to eliminate the temperature difference that occurs in the rice storage area due to the influence of outside air at the time of natural cooling, in addition to keeping the rice in a high temperature range for a long time while saving energy without controlling the heat insulation of the rice Can be prevented or suppressed.

  According to the electric rice cooker of the present invention, utilizing the high correlation with the temperature of the rice of the main sensor, leading the heat insulation heating control, the response of the bottom heating source and the side heating source to the main sensor While maintaining the overall temperature of the pan and rice at the target temperature without any temperature difference, the temperature compensation at the bottom is ensured, and the side heating source responds to the side auxiliary sensor. Temperature compensation on the lid side where the outside air temperature is affected by the response of the lid heating sensor to the lid sub-sensor and the temperature deviation due to the excessive or insufficient response of the side heating source led by the sensor and the influence of the outside air temperature. , So there is no scorching or stickiness at the bottom, eliminating white blur caused by condensation on the surface of the rice or dryness caused by excessive heating, and maintaining the specified temperature range even with the minimum amount of rice cooked And keep the rice warm Can.

  Moreover, such heat insulation heating control can be omitted and energy saving can be achieved until the temperature of the rice drops to the heat insulation temperature.

  In addition, while the heat insulation and heating control is omitted, the condensation of the rice is prevented or suppressed by a small amount of power consumption that only eliminates the temperature difference that occurs in the rice storage area due to the influence of outside air during natural cooling. Can prevent quality degradation.

  Hereinafter, embodiments of the electric rice cooker according to the present invention will be described in detail with reference to FIGS. 1 to 11 to provide an understanding of the present invention.

  As shown in FIG. 1 and FIG. 2, the electric rice cooker according to the present embodiment is mainly a non-metallic pot 1 such as a clay pot, a main body 2 that can be attached and detached, and a main body 2 and a pan 1. And a lid heating source 4 for heating from the bottom of the pan 1, a side heating source 5 for heating from the side of the pan 1, and a lid heating source 6 for heating from the lid 3. It has a basic configuration. The main body 2 is provided with a heating coil 4a of the bottom heating source 4 between the inner and outer cases 11 and 12, and a heating element 4b that is inductively heated by an alternating magnetic field from the heating coil 4a is provided at the bottom of the pan 1 opposite to the heating coil 4a. is there. Specifically, although it is provided on the outer surface of the bottom of the pan 1, it may be an inner surface or may be embedded. The side heating source 5 is a heat retaining heater 5a wound around the outer periphery of a metal body frame 11a sandwiched between a resin lower frame 11b and an upper frame 11c in the interior case 11. However, the side heating source 5 can also be a combination of a heating coil (not shown) and a heating element on the pan 1 side. The lid heating source 6 is a lid heater 6a that is wired and attached to the upper surface of a metal heat radiating plate 3c fitted to a resin lower plate 3b combined with a resin upper plate 3a of the lid 3. The heat radiating plate 3c has a size corresponding to the opening of the pan 1, and heats the rice in the pan 1 from above the metal inner lid 7 that closes the opening of the pan 1, and mainly heats the side. In cooperation with 5, keep warm while preventing condensation due to temperature difference. Here, the lid heating source 6 can also be a combination of a heating coil and a heating element. In this case, the heating element is a metallic inner lid 7 itself or a heating element provided on the inner lid 7 made of non-metal. The heating coil provided on the lid 3 side may be opposed to the magnetically permeable structure. The bottom heating source 4 can be used in combination with the heat insulation of the rice. In particular, the bottom heating source 4 is divided into a central part of the bottom of the pan 1 and an outer peripheral part that rises, for example, in the shape of a round, to the bottom part of the pan, and a combination of a heating coil 4a1 and a heating element 4b1 at the center The heating coil 4a2 and the heating element 4b2 are separated. However, the heating coils 4a1 and 4a2 are configured to perform the same energization control as a configuration in which one wire is wound in two places. However, the present invention is not limited to this, and individual energization control can be performed by configuring individual lines.

  As shown in FIG. 1, a power source / driving board 111 for driving the bottom heating source 4, the side heating source 5, and the lid heating source 6, and an operation for cooking rice or cooking in a mode set through the power source / driving board 111. The control board 112 is arranged in a large space formed between the front portions of the inner and outer cases 11 and 12 of the main body 2, and a heating element such as an IGBT cooperating with the heat sink 13 a by the fan 13 is blown as indicated by an arrow A It is designed to cool. The fan 13 is also a heater disposed around the bottom of the interior case 11 of the main body 2 by air blowing as indicated by an arrow B by the guide 113 extending from the lower part of the power source / drive substrate 111 to the bottom of the pot 1. The coils 4a1 and 4a2 are cooled, and the air flows around the upper part of the interior case 11 to cool the coils 4a1 and 4a2 through the electromagnetic ventilation part 124a provided at appropriate positions in the interior case 11 and cool it. You can also.

  On the upper surface of the wide front part of the main body 2, there is provided an operation panel 14 for setting various modes, starting rice cooking and cooking, selecting and stopping heat insulation, and an operation board 18 on the inside thereof. It corresponds to various operations on the operation panel 14 and can display the operation state and the operation state. A take-up reel 115 for the power connection cord is accommodated between the rear portions of the main body 2 as a slightly larger space than between the side portions. The lower frame 11b and the upper frame 11c of the interior case 11 of the main body 2 are made of resin so that the lower frame 11b satisfies the magnetic permeability so as not to disturb the electromagnetic action on the heating elements 4b1, 4b2 by the heating coils 4a1, 4a2. Yes. The outer case 12 of the main body 2 is connected to the upper end of the peripheral wall of the resin bottom member 12a by forcibly fitting the lower end edge winding portion of the metal barrel portion 12b, and the upper end of the barrel portion 12b and the upper frame 11c of the interior case 11 are connected. The upper end is connected by a shoulder member 12c made of synthetic resin. The heating coils 4a1, 4a2 are placed on and supported by a resin coil base 15, and ferrite 16 extending radially below the coil base 15 is supported by a resin support base 17, and the heating coils 4a1, 4a2 are provided. The magnetic field generated by is strengthened and stabilized.

  As shown in FIG. 1, the lid 3 is pivotally supported by the rear bearing portion 2d of the main body 2 by a shaft 21 so as to be opened and closed, and is urged in the opening direction by a spring 22, and by sliding contact between the spring 22 and the rear bearing portion 2d. The lid 3 is opened slowly by resistance or the like. The front portion of the lid 3 is locked at a closed position by a lock lever 23 provided on the side of the main body 2 so as to be pivotally supported by the shaft 124, so that the lock is released by the unlocking operation of the lock lever 23 and is opened by the spring 22. I have to. In such a closed state of the lid 3, the seal packing 24 sandwiched between the lower plate 3 b and the heat radiating plate 3 c of the lid 3 is pressed against the outer peripheral frame 7 a of the inner lid 7 as shown in FIGS. 1 and 2. In this state, the inner lid 7 is pressed against the horizontal lip of the pan 1 from above with a seal packing 25 provided between the outer peripheral frame 7a, the pan 1 is closed, and rice is cooked or kept warm. Become. In such a closed state, the inner lid 7 has holes (not shown) in the high and low portions, and escapes steam during cooking, or causes the escape from the inner lid 7 accompanying the escaped steam. It can be returned to the pot 1. Further, a steam pipe 27 is inserted into the hole 26 provided in the center of the lid 3 from below and is held by a seal packing 28 on the inner periphery of the hole 26 so that it can be attached and detached for disassembly and cleaning. The steam pipe 27 has a steam passage 29 having a ball-like check valve 29a, and discharges the steam that has flowed out of the inner lid 7 to the outside of the lid 3 only when the valve pressure of the check valve 29a is exceeded. While the gas-liquid separated rice bowl is returned to the inner lid 7, it is returned to the pot 1.

  Here, the non-metallic pan 1 may be mainly made by firing porcelain clay, but also includes ceramics and various known ones can be adopted. The heating elements 4b1 and 4b2 of the bottom heating source 4 are conductive layers that generate heat by generating eddy currents by alternating magnetic fields from the heating coils 4a1 and 4a2, and are silver paste of about 10 to several tens μm provided on the outer surface of the pan 1 or the like. It may be a coating layer by printing, a silver foil bonding layer, a silver deposition layer, an embedded layer, or the like. However, the conductive material and the layer formation method can be freely selected. The heat retaining heater 5a of the side heating source 5 is equipped with being sandwiched between the outer surface of a heat radiating plate 11a made of aluminum, steel plate, stainless steel or the like facing the side of the pan 1, and used mainly for heat retaining. In particular, the lower part of the heat retaining heater 5a is also suitable for cooking rice. Furthermore, although it mentions later in this embodiment, it has control modes of various rice cooking modes, the heat retention mode following the rice cooking mode, the non-heat retention mode following the rice cooking mode, regarding the heat retention of rice and rice, for these, While the uppermost one of the quadruple heaters 5a has an energization capacity equivalent to 60 to 70W, the opening of the pan 1 and the lid 3 side have sufficient temperature compensation ability to be easily lowered due to the influence of the outside air temperature, The middle part is 20-30, and the two lowermost parts have a current carrying capacity equivalent to 40-50W. The difference in energization capacity can be easily obtained by the difference in duty ratio of energization, and may be obtained in any way. Using this difference in energization capacity, various factors such as the total number during rice cooking, condensation in the heat retention mode, whitening, browning due to drying, condensation in the non-heat retention mode, and yellowing due to delay in cooling, etc. Fine heating control according to conditions is possible.

  As described above, various rice cooking modes, cooking modes, heat retention modes, and no heat retention modes can be executed according to the selection operation, start operation, and stop operation on the operation panel 14.

  In addition, in the non-metallic pot 1 such as a clay pot, the heat of the heating elements 4b1 and 4b2 provided on the outer surface thereof is not transmitted efficiently to the pot 1 side, so that the interior case 11 side and the heating coils 4a1 and 4a2 The ratio of heat dissipation to the side increases, and rice cooking cannot be carried out successfully, or if the heating temperature during cooking is increased to ensure the rice cooking temperature, local overheating on the pan 1 side, especially this heating element that becomes this local overheating part 4b1 or the like may cause deterioration or melting damage of the lower frame 11b of the interior case 11 and abnormal heat generation of the heating coil 4a1 or the like, which may impair the safety of the rice cooker or use. Therefore, a magnetically permeable heat-resistant plate 31 is disposed in a portion of the pan 1 of the lower frame 11b in the interior case 11 that is opposed to the heating element 4b1 that has a particularly large radial width and a large total calorific value, so that heat from the heating element 4b1 can be obtained. Corresponding to reflect. Specifically, the permeable heat-resistant plate 31 provided in a portion of the main body 2 facing the heating element 4b1 provided on the outer surface of the pan 1 of the interior case 11 is provided with at least the inner and outer cases 11 and 12 by the permeability. It does not impair the effect of inducing heat generation by applying an alternating magnetic field from the heating coil 4a1 provided between the bottoms to the heating element 4b1 on the outer surface of the pan 1 facing it. Moreover, this heat-resistant heat-resistant plate 31 is made of a non-metallic material such as a clay pot, which has a low thermal conductivity, whereas the heating element 4b1 on the outer surface of the pot 1 generates heat at a high temperature necessary for good rice cooking. Even if the ratio of heat radiation from the heating element 4b1 or the like to the outer surface of the interior case 11 is high, the heat radiation is reflected on the surface of the heat-resistant plate 31 to the pan 1 side, so Heating efficiency can be improved by heating again and using it again for cooking rice. As a result, it becomes easy to realize good cooked rice with uniform and sufficient heating from the combination of the non-metallic pan 1 with the thick and easy-to-heat characteristics. Furthermore, the heat-resistant plate 31 is not deteriorated or damaged due to its heat resistance, and heat from the heating element 4b1 on the outer surface of the pan 1 does not reach the interior case 11, particularly the lower frame 11b and the heating coil 4a1 of the main body 2. In addition, it is possible to avoid heat from reaching the outer case 12 of the main body 2.

  Corresponding to the fact that the heat-resistant plate 31 reflects the heat from the heating element 4b1 and the like to the pan 1 side, an air gap 32 is provided between the pot 1 and the heating element 4b1 and the heat-resistant plate 31. Is essential. In particular, it is desirable that the air gap 32 is a closed space and is opened at least around so as not to generate heat. In the present embodiment, the air gap 32 is an annular formed on the outer periphery of the bottom of the pan 1. 2 at the height around which the leg 1d is supported by the elastic support 33 made of silicon rubber or the like shown in FIG. 2 provided at about three places on the circumference of the bottom outer periphery of the lower frame 11b. Just secure. However, the air gap 32 can also be secured by receiving and suspending the flange 1 c of the opening of the pan 1 by the opening of the main body 2. The placement and support on the elastic support base 33 by the leg 1d of the pan 1 also exhibits the effect of elastic support of the pan 1 and rotation prevention. On the other hand, as shown in FIGS. 1 and 2, the air gap 32 is formed in the entire area between the interior case 11 and the pan 1 while preventing the heat effect from the pan 1 side to the interior case 11 side. The heat is spread between the interior case 11 and the pan 1, and it becomes easy to promote heating efficiency and uniform heating in cooperation with the heating of the pan 1 and the cooked rice, which are made of non-metal thick and low heat conductivity. In particular, the heat-resistant plate 31 provided in the interior case 11 of the main body 2 is easy to make use of the heat reflected on the pan side.

  Furthermore, the heat-resistant plate 31 has a hole 35 in the central portion for bringing the main sensor 34 into contact with the pan 1 and is larger than the outer diameter of the opposing heating element 4b1. Thereby, the temperature of the center part of the bottom part of the pan 1 having high correlation with rice cooking can be detected by the main sensor 34 through the hole 35 in the center part. For this purpose, as shown in FIGS. 1 and 2, the main sensor 34 is provided at the center of the coil base 15 and is urged upward by a spring, penetrates the lower frame 11b and the heat-resistant plate 31, and always protrudes thereon. The temperature of the pan 1 can be monitored by being in pressure contact with the bottom of the pan 1 placed on the support base 33.

  The pan 1 has a lower half 1b that is thinner than the facing portion 1e facing the side heating source 5. Thus, the pan 1 is housed so as to be detachable from the main body 2, and the cooking of rice and rice is performed by heating from the bottom heating source 4, the side heating source 5 and the lid heating source 6. The lower half 1b of 1 is thinner than the facing part 1e facing the side heating source 5 and has a smaller heat capacity, so that heat from the heating elements 4b1, 4b2 important for rice cooking is used for primary heating by the direct heat conduction. The secondary heating by the heat reflected from the heat-resistant plate 31 is obtained, and the heating efficiency is further improved, and sufficient cooking rice heating is realized while suppressing to a relatively low energization capacity, and good rice cooking can be performed. In addition, the pot 1 is opposed to the side heating source 5 and the portion 1e is thicker than the lower half 1b and has a higher heat storage capacity. It becomes easy to keep the rice uniformly warm based on the characteristics and the heat assistance based on the heating from the side heating source 5 and the heating from the lid heating source 6.

  Moreover, although the pan 1 makes the lower half part 1b facing the bottom heating source 4 thinner than the facing part 1e facing the side heating source 5, the thickness of the facing part 1e facing the side heating source 5 is larger. The drop-resistant strength is not impaired by the cooperation. In particular, the required strength when falling in an upright posture is satisfied. And the high output heating from the bottom heating source 4 makes the rice cooking heat easier to live by the amount that the lower half 1b that is opposite to the bottom heating source 4 is thin and the heat storage capacity is small, and thick side heating The heat transfer to the facing portion 1e with the source 5 is also promoted. Therefore, the rice in the uniform heating accompanied by the active convection in the water in the pan 1 and the whole area of the rice is realized. Here, it can be said that the side of the pan 1 is thick at the top and thin at the bottom including the bottom rounded portion of the pan 1, but the thin region extends to the side region where the drop resistance strength of the pan 1 is full. By doing, the rice cooking characteristic in the uniform heating by the high output heating from the bottom part heating source 4 using the thin part of the pan 1 further increases. The thick portion and the thin portion of the pan 1 are continuous by forming a rounded step portion D on the outer surface of the pan 1, and a relatively rapid change in thickness is achieved without stress concentration.

  Here, if one example is shown, it is made of a ceramic mainly composed of mullite and cordierite, and a glass-based glaze where the mainstream is a uniform thickness of about 10 to 15 mm in a normal clay pot. For the pan 1 that has been sealed, the thickness of the lower half 1b that is the facing portion to the bottom heating source 4 is about 3 to 4 mm, and the thickness of the facing portion 1e to the side heating source 5 is about 7 to 8 mm. Sufficient drop-proof strength was obtained, and rice cooked by uniform heating and uniform heat retention were realized. From such a dimensional relationship, the difference in thickness between the thick portion and the thin portion of the pan 1 can be approximately doubled. In addition, since there is no heating source between the opposing part with the trunk | drum frame 11a which is a heat sink of the heat retention heater 5a of the pan 1, and the part which has the heat generating body 4b2 which opposes the heating coil 4a2, the thickness of the pan 1 is small. It is advantageous for uniform heating during cooking, and is preferably about 3 mm. In some cases, it is thinner than the thickness set in the lower half 1b of the pan 1 on condition that the drop-proof strength is satisfied. May be.

  Furthermore, as shown in FIG. 3, the opening of the pan 1 is thickened by t, for example, from the side to the inside. Thereby, although the opening part of the pan 1 is easily affected by the outside air due to the lid closing structure, the temperature tends to decrease, but the heat storage capacity increases due to the increased thickness t from the side part of the opening part, and the heat during cooking is increased. It is possible to store the heat and suppress the temperature drop due to the outside air, and it is possible to prevent the occurrence of dew condensation due to the temperature difference even at the start of heat retention immediately after cooking of rice with a lot of moisture. If the thickness t is too large, it takes too much time to raise the temperature. Therefore, the thickness t is preferably less than 6 mm. If the thickness t is too small, a heat storage effect cannot be obtained. Further, the seal packing 25 of the inner lid 7 is in a positional relationship such that it is pressed against the flat upper surface 1e1 of the flange 1c of the pan 1. Further, it is more preferable that the flat upper surface 1e1 is substantially horizontal. As a result, the forming error of the opening of the pan 1 is as large as ± 2 to 4 mm when the metal pan is ± 0.5 mm in terms of radius, but in such an error range, the seal packing 25 is located on the upper surface of the flange 1c. 1e1 is not deviated, and the press contact width and the seal width are increased, so that the seal can be prevented from coming off due to the biting of foreign matter, and the problem of poor seal can be avoided. For this purpose, if the thickness t from the side of the opening of the pan 1 is increased inward, it is advantageous to easily widen the upper surface 1e of the flange 1c. Moreover, the outer peripheral part of the flange 1c is also made thicker by t1 than the inner peripheral side which is substantially the same thickness as the side part of the pan 1, thereby increasing the strength of the opening of the pan 1. The increase in thickness in this case has an advantage that it is easy to prevent the leakage of juice to the outside on the upper surface 1e1 of the flange 1c by facing upward as shown in the figure. Furthermore, the leg 1d of the pan 1 is positioned between the heating elements 4b1 and 4b2, and can be positioned when the heating elements 4b1 and 4b2 are attached. However, the heating elements 4b1 and 4b2 can also be provided in an embedded state on the surface of the pan 1 as shown in FIGS. 1 and 2, and the recesses for that are positioned when the heating elements 4b1 and 4b2 are provided, and the heating elements When 4b1 and 4b2 are provided so as to be flush with the outer surface of the pan 1, it is easy to prevent inconveniences such as the surroundings of the heating elements 4b1 and 4b2 being caught and peeled when the pan 1 is washed. If a heat insulating wall 145 is provided around the heat insulation heater 5a, the heat of the heat insulation heater 5a can be efficiently utilized for heat insulation without escaping to the outside.

  Further, according to the experiments of the present inventors, the heat generation amount of the heating elements 4b1, 4b2 tends to show a temperature distribution in which the temperature is high in the central part and the temperature is low on the peripheral side in the radial direction. The temperature difference becomes larger as the thickness of the pan 1 increases. Even if the pan 1 is made of a non-metal having low thermal conductivity, the lower half 1b of the pan 1 is opposed to the side heating source 5 as described above. In the configuration where the thickness is made thinner, the temperature distribution as described above is somewhat reflected as the heating unevenness at the time of rice cooking, so that the temperature unevenness is suppressed to a level that does not cause any problem by making a difference in the thickness of the heating elements 4b1 and 4b2. ing. Specifically, the heating element 4b2 has a smaller width in the radial direction and a smaller temperature distribution than the heating element 4b1, so that the central part in the radial direction is thin and the peripheral part is thick. On the other hand, since the heating element 4b1 has a large width dimension in the radial direction and a large temperature distribution difference, the heating element 4b1 at the central part where the temperature becomes high is eliminated, or the ratio of the thickness of the central part to the thickness of the peripheral part is The heating element 4b2 is made smaller than the case. This improved the uneven heating during cooking. This is because if there is a partial thickness difference between the heating elements 4b1 and 4b2, the amount of current is concentrated and the amount of heat generation is greater than that of the thin-walled portion. It seems to be due to this. Such a partial thickness difference can be easily realized by partially changing the number of times of application, and a portion of thickness 0 where no heating element is provided can be realized by omitting application of the heating element. Here, if two examples of L-2 (100 size) and K (150 size) are shown, favorable results were obtained as a dimensional relationship and a thickness relationship as shown in FIG.

  In response to the high power heating from the bottom heating source 4 as described above, the resin portion of the interior case 11 is conventionally formed of PET together with the resin portion of the exterior case 12, but the heat resistant temperature is as low as about 150 ° C. Since there is a concern about thermal influence, in this embodiment, the upper frame 11c and the lower frame 11b are made of PPS having a high heat resistant temperature of about 250 ° C., and adhesion of the heat resistant plate 31 to the silicon-based adhesive can be achieved without any problem. ing. On the other hand, the bottom member 12a and the shoulder member 12c of the outer case 12 are made of resin such as PET as usual. In addition, as shown in FIG. 2, recesses 41 for facilitating clues to the flange 1c are formed between the shoulder member 12c and the flange 1c of the pan 1, as shown in FIG. A handle 118 that reaches the shoulder member 12c and is supported is provided on the upper portion of the body 12b.

  In order to execute the above-described heat retention mode, the present inventor, based on the above-described experimental results, in addition to the main sensor 34 having a high correlation with the rice cooking temperature and the rice temperature, further, the main body side together with the side heating source 5 The side sub-sensor 121 provided on the heat radiating plate 11a and the lid sub-sensor 123 provided on the heat radiating plate 3c on the lid 3 side together with the lid heating source 6 are further provided, and the side sub-sensor 121 particularly affects the influence of outside air. Position close to the opening of the pan 1 and the surface of the rice that is easy to receive, specifically, as shown in FIG. 1, between the upper edge winding portion 11a1 of the heat radiating plate 11a and the upper thermal insulation heater 5a, more preferably the upper edge winding portion 11a1 is provided in the vicinity.

  From this condition, in the present embodiment, in the heat retaining mode, the lid heating source 6 is caused to respond to the set value of the lid sub sensor 123 and the side heating source 5 is set to the set value of the side sub sensor 121. The basic characteristic is that the heat-retention heating control is performed by causing the bottom heating source 4 and the side heating source 5 to respond to the set value of the main sensor 34. Thereby, in order to lead the heat insulation heating control using the high correlation with the temperature of the rice of the main sensor 34, the bottom heating source 4 and the side heating source 5 with respect to the set value of the main sensor 34. To keep the overall temperature of the pan 1 and the rice at the target temperature without any temperature difference from the empirical temperature relationship between the bottom and the body of the pan 1, and there is no burning, and the rice There is no minimum excess or deficiency with respect to the bottom portion that is not sticky, and therefore, temperature compensation is ensured, and the temperature deviation due to the excess or deficiency of the response of the side heating source 5 with respect to the set value of the main sensor 34 or the influence of the outside temperature. The lid body 3 portion that is made more appropriate by the response of the side heating source 5 to the set value of the side auxiliary sensor 121 and reflects the result of the external temperature effect by the response of the lid heating source 6 to the set value of the lid auxiliary sensor 123, particularly On the inner lid 7 It is possible to ensure the temperature compensation from above that.

  As a result, by utilizing the high correlation with the temperature of the rice of the main sensor 34, the heat insulation heating control is led, and the bottom sensor 4 and the side heating source 5 respond to the main sensor 34 in the pan. 1 and the whole heat-retaining temperature of the rice is maintained at the target temperature without any temperature difference, ensuring temperature compensation at the bottom of the pan 1 without excess or deficiency, and the response of the side heating source 5 to the side auxiliary sensor 121 In the lid, the temperature of the side heating source 5 driven by the main sensor is more appropriate and the temperature deviation due to the influence of the outside air temperature is optimized, and the outside air temperature is influenced by the reaction of the lid heating source with respect to the lid sub-sensor 123. Since temperature compensation on the body 3 side is also secured, there is no scorching or stickiness at the bottom, eliminating white blur caused by condensation on the surface of the rice or dryness caused by excessive heating, even with the minimum amount of rice cooked Preserved temperature range can be maintained, rice It is possible to quality well-kept warm.

  Such heat insulation heating control is based on the three temperature information from the lid sub-sensor 123, the side sub-sensor 121, and the main sensor 34, and maintains the temperature balance of the whole rice storage area, and thus the whole pan 1 and rice. It can be said that it is heating control, and this is the best embodiment.

  The relationship between the sensor and the heating source that responds to it is summarized as shown in Table 3 below. However, the specific setting example is complicated and there is no practical use to show this, so the description is omitted. .

特に、側部加熱源５は、既述したように上段の保温ヒータ５ａ、中段の保温ヒータ５ａ、下段の保温ヒータ５ａの３つを有していることから、目標温度に対する主センサの設定値以上と未満で、蓋加熱源６と、側部加熱源５の上段保温ヒータ５ａと、側部加熱源５の中段保温ヒータ５ａおよび下段保温ヒータ５ａと、の３つの単位で、通電容量を変えて保温加熱制御を行うようにする。これにより、主センサ３４のある目標温度に対応した設定値以上か未満かで、蓋加熱源６と、側部加熱源５の上段保温ヒータ５ａと、側部加熱源５の中段保温ヒータ５ａおよび下段保温ヒータ５ａと、の３つの単位で通電比率を変えるので、主センサ３４主導の保温加熱制御における温度補償が蓋加熱源６にも及ぶし、側部加熱源５に対しては上段保温ヒータ５ａと、中段保温ヒータ５ａおよび下段保温ヒータ５ａと、に分けて独立した通電率変化にて及ぶことになるので、ご飯収容域の全体についての保温加熱制御をさらにきめ細かく、かつむらなく行いやすくなる。

In particular, since the side heating source 5 includes the upper heat retaining heater 5a, the middle heat retaining heater 5a, and the lower heat retaining heater 5a as described above, the set value of the main sensor with respect to the target temperature. As described above, the energization capacity is changed in three units of the lid heating source 6, the upper heating heater 5 a of the side heating source 5, and the middle heating heater 5 a and the lower heating heater 5 a of the side heating source 5. Keep warm and heat control. Accordingly, the lid heating source 6, the upper heating heater 5 a of the side heating source 5, the middle heating heater 5 a of the side heating source 5, and the like depending on whether or not the set value corresponds to a certain target temperature of the main sensor 34. Since the energization ratio is changed in three units of the lower stage warming heater 5a, temperature compensation in the warming heating control led by the main sensor 34 extends to the lid heating source 6, and for the side heating source 5, the upper stage warming heater 5a, the middle stage heater 5a, and the lower stage heater 5a are divided into independent energization rate changes, so that the heating and heating control for the whole rice storage area can be performed more finely and uniformly. .

  The relationship between the sensor and the heating source that responds to the above is summarized as shown in Table 4 below, but the specific setting example is complicated and there is no practical use to show this, so the description is omitted. .

さらに、本発明者は、前記１００サイズタイプと１５０サイズタイプとのそれぞれにつき、炊飯後の鍋１内のご飯の無加熱状態において、炊飯量が最大、つまり前者では５．５合、後者では８合の炊飯量の場合での経時的な温度変化とご飯の状態を実測した。なお、温度の検出は１００サイズの場合図５（ａ）に示す３つの位置条件にて、１５０サイズの場合は図５（ｂ）に示す３つの位置条件にてご飯内に挿入した熱電対により行った。それぞれの場合の経時的なご飯の温度変化は図６に示す通りであり、図６からご飯の降温状態を最も低くなる表面温度で見ても、１００サイズ、１５０サイズとも３時間を経過してなお７０℃範囲をキープできていて、土鍋など非金属製の鍋１の高い保温性が認められる。

Furthermore, the present inventor has the maximum amount of rice cooked in the non-heated state of the rice in the pan 1 after cooking for each of the 100 size type and the 150 size type, that is, 5.5 for the former and 8 for the latter. The temperature change over time and the state of the rice in the case of the total amount of cooked rice were measured. The temperature is detected by the three position conditions shown in FIG. 5 (a) for the 100 size, and by the thermocouple inserted in the rice under the three position conditions shown in FIG. 5 (b) for the 150 size. went. The change in the temperature of rice over time in each case is as shown in FIG. 6, and even if the temperature drop state of rice is seen at the lowest surface temperature from FIG. In addition, the 70 degreeC range can be kept and the high heat retention property of nonmetallic pots 1 such as a clay pot is recognized.

  Corresponding to such experimental results, the above-described heat and heat control is performed at a predetermined time after cooking rice. Thus, since the heat insulation heating control is performed after that until a predetermined time point such as when an appropriate heat insulation temperature of 70 ° C. can be ensured, it is eliminated that the heat insulation heating control is wasted.

  In addition, from the cooked rice to a predetermined point in time, dew-conforming heating control is performed to prevent dew condensation in the rice storage area. In this way, while the heat insulation heating control is not performed, it is a natural temperature drop from rice cooking to the heat insulation heating control, and a partial temperature difference due to the influence of the outside air is generated, causing condensation and impairing the quality of the rice. On the other hand, the heat control of the rice was omitted by the natural heat insulation utilizing the heat storage and heat retention of the non-metallic pot 1 by performing the condensation control corresponding to preventing or suppressing the condensation in the rice containing area. In addition to keeping the rice in a high temperature range for a long time while conserving energy, it prevents or suppresses condensation with a small amount of power consumption that eliminates the temperature difference that occurs in the rice storage area due to the influence of outside air when the temperature naturally falls. Can prevent the quality of the product from deteriorating.

  As shown in Table 5 below for both 100 size and 150 size,

底部加熱源４の通電なしの状態で、蓋ヒータ６ａを５秒オフ、５秒オンの繰り返し、上部保温ヒータ５ａを４秒オフ、４秒オンの繰り返し、中間保温ヒータ５ａを３秒オフ、３秒オンの繰り返し、下保温ヒータ５ａを２秒オフ、２秒オンの繰り返し、の通電制御の組み合わせにて、検出温度に基づく温度制御なしに好結果が得られた。

While the bottom heating source 4 is not energized, the lid heater 6a is turned off for 5 seconds and turned on for 5 seconds, the top heat retaining heater 5a is turned off for 4 seconds and turned on for 4 seconds, and the intermediate heat retaining heater 5a is turned off for 3 seconds. A good result was obtained without the temperature control based on the detected temperature by combining the energization control of repeating the second on and turning off the lower heat retaining heater 5a for 2 seconds off and repeating the second on.

  However, taking advantage of the heat-retaining property of the pan 1, after cooking the rice, it can be taken out from the main body 2 and closed with a non-metallic lid, placed on a table and used as a bowl, and served for a certain period of time. In this case, the condensation-controlling heating control cannot be executed, but if a cloth or the like is sandwiched between the pan 1 and the lid, the problem of condensation can be reduced. Instead of this, the inner surface of the pan 1 or the lid can be made to have a hygroscopic surface structure.

  By the way, the temperature difference over time, which causes condensation during natural temperature drop in the rice storage area, can be known from experience as well as from temperature detection at each part, preventing or suppressing condensation. However, the influence of room temperature is unknown from experience, although it is possible to arrange a heat source that is compatible with condensation and to control the energization. For this reason, the room temperature sensor 122 is used for heat insulation by the condensation heating source such as the side heating source 5 and the lid heating source 6 that are provided on the metal inner lid 7 that closes the pan 1 to prevent condensation. In the dew condensation-compatible heating control in the no mode, the energization capacity to the dew condensation-compatible heating source is changed corresponding to two or more temperature ranges of room temperature detected by the room temperature sensor 122. Thus, by conducting energization control to the condensation-compatible heating source based on a difference in at least two temperature ranges of the room temperature detected by the room temperature sensor 122, of course, in the case of performing condensation-controlled heating control based on experience, Even when the temperature difference that causes it is difficult to reflect the room temperature, it is possible to perform the heating control for dew condensation considering the room temperature.

  Here, one embodiment in this case is shown. When the room temperature is 5 ° C., the lid heater 6a, the upper-stage insulation heater 5a, the middle-stage insulation heater 5a, and the lower-stage insulation are shown in FIG. The energization setting constant for the heater 5a is shifted as shown in Table 6 below.

室温が２０℃である場合には、蓋ヒータ６ａ、上保温ヒータ５ａ、中保温ヒータ５ａ、下保温ヒータ５ａへの通電設定定数を下記の表７に示すようにシフトし、

When the room temperature is 20 ° C., the energization setting constants for the lid heater 6a, the upper insulation heater 5a, the middle insulation heater 5a, and the lower insulation heater 5a are shifted as shown in Table 7 below.

室温が３５℃である場合には、蓋ヒータ６ａ、上保温ヒータ５ａ、中保温ヒータ５ａ、下保温ヒータ５ａへの通電設定定数を下記の表８に示すようにシフトし、

When the room temperature is 35 ° C., the energization setting constants for the lid heater 6a, the upper insulation heater 5a, the middle insulation heater 5a, and the lower insulation heater 5a are shifted as shown in Table 8 below.

いずれの場合も好適な結露防止ができた。しかも、このような保温加熱制御なしにも３時間経過して７０℃程度のご飯温度を確保できることから、保温モードに加え、保温なしモードを設けてこれを選択した場合保温加熱制御を省略しても、食事時間に少々のバラツキがあるユーザや家族間でも特に不便とならず、省エネができる。

In any case, suitable dew condensation prevention was achieved. Moreover, since the rice temperature of about 70 ° C. can be secured even after 3 hours without such heat insulation heating control, in addition to the heat insulation mode, when there is no heat insulation mode and this is selected, the heat insulation heating control is omitted. However, it is possible to save energy without inconvenience between users and families who have a little variation in meal time.

  In the non-insulation mode, the heating and heating control is not performed, so the temperature of the rice greatly decreases with time, and when it approaches about 65 ° C, it becomes a breeding temperature range of miscellaneous bacteria. Specifically, it is preferable to stop when 3 hours have elapsed or when the temperature has fallen below 70 ° C. As a result, if the temperature control for condensation is performed until reaching one of the two time points, that is, the time point when the predetermined time has elapsed and the time point when the predetermined temperature drop is reached, it is possible to reliably cope with one of the two conditions specific to the time point of arrival. it can.

  Since the outside air temperature also affects the heat insulation and heating control, it must be reflected in the heat insulation and heating control. Therefore, the temperature information of the room temperature sensor 122 that detects the room temperature provided on the operation / control board 112 as shown in FIG. Therefore, it is preferable to change the conditions for reacting the bottom heating source 4, the side heating source 5, and the lid heating source 6 in the relationship shown in Tables 3 and 4.

  If the change of the heat retention temperature of the whole ideal rice storage area with respect to the time passage by the heat retention heating control as described above is schematically shown in FIG. As shown in FIG. 7B, after the rice cooking is finished, the heat control 4 from the heat control 1 and the heat control 4 are performed. In addition, the control corresponding to the room temperature shown in FIG. 7C does not change much at room temperature from the heat insulation control 1 to the initial stage of the heat insulation control 4 and is invalidated by the room temperature sensor invalid timer 1 and the influence of the room temperature can be affected. It is made to run from the time when it disappears. For room temperature, it is preferable to use real information during the heat retention. As shown in FIG. 7 (d), it is observed in about three stages of 5 ° C., 20 ° C., and 35 ° C. It is good to change. As shown in FIG. 7 (e), the room temperature sensor 122 can take in the temperature at intervals of about 600 seconds, and the thermal insulation heating control is stopped at a maximum of about 12 hours as shown in FIG. 7 (f). While the bottom heating source 4 of the heat insulation heating control is not turned on, the detection of the pot 1 is periodically performed at intervals of about 600 seconds by a temperature rise determination by the main sensor 34 by turning on the heating coil 4a1 and the like for a short time. When the IGBT provided on the power source / drive board 111 is turned on to drive the heating coils 4a1, 4a2 from the heat insulation heating control, the pot 1 can be detected by the temperature rise at that time, and the pot 1 is detected periodically. The operation can be omitted. FIG. 7G shows the relationship between the heat retaining power of the heat retaining heater 5a and the set value of each sensor in the heat retaining heating control.

  In addition, although not illustrated, the change in the energization control to cope with the temperature drop to about 65 ° C. with the minimum rice cooking amount is based on the temperature rise information at a predetermined time such as the main sensor 34 in the temperature raising process at the time of rice cooking. Since the total number is determined, the information may be stored and adopted.

  Here, an example of heat retention control after rice cooking by a microcomputer as a control device mounted on the operation / control board 112 will be described below according to a flowchart shown in FIG.

When the end of cooking is confirmed, it is determined whether or not the non-insulating mode is selected, a standby timer is started that measures the waiting time when heating by the condensation-compatible heating control is required, and waits for the standby timer 1 to end. Heating control corresponding to dew condensation by energization control to the heat source corresponding to dew condensation as shown in the previous examples of Tables 1 to 4 is started. Condensation-responsive heating control is continued until the condensation-response timer is counted with the start of the condensation-response heating control, or until the condensation-response timer expires or the rice reaches a predetermined temperature drop. If the dew condensation response timer expires or ends, or if the rice reaches a predetermined temperature drop, if the non-heat retention mode is selected, the dew condensation response control is terminated. If the non-insulation mode is not selected, it is determined that the insulation mode is selected, and the condensation control heating control is terminated. Table 3
Then, the process shifts to heat insulation and heating control based on the relationship shown in Table 4 and FIG. A warming timer is started with the transition to the warming and heating control, and the warming and heating control is terminated when this timer is finished.

  Here, the waiting time by the waiting timer avoids useless or excessive condensation control heating control corresponding to the good heat retaining property of the pan 1, but is not essential.

  Further, in the dew-conforming heating control in the non-insulation mode, the temperature sensor that can determine the temperature of the rice to be lowered by utilizing the fact that the fan 13 can cool the pan 1 as described above, that is, the main sensor 34 described above, In combination with one or both of the side sub-sensors 121, when the temperature of the rice in the no heat retention mode has decreased to a predetermined temperature, for example, more than 3 hours, the fan 13 is driven to move the pan 1 It can be cooled to promote the temperature drop of the rice. As a result, when the cooked rice does not reach the predetermined temperature drop after a predetermined time for some reason, it begins to cause quality changes such as yellowing in the rice. Such a change in quality can be prevented by driving to cool the pan 1 and promote the temperature drop of the rice. In this case, when the pan 1 is cooled by the fan 13, the electromagnetic ventilation part 124 a provided in the interior case 11 can be temporarily opened to guide the air blown from the fan 13 around the surface of the pan 1 to enhance the cooling effect.

  Further, when the lid 3 is opened during the heat retention mode, the detection temperature of a specific sensor, for example, the lid sub-sensor 123, suddenly drops and continues for a predetermined time, so that the lid 3 is opened with high accuracy. Can be judged. Therefore, by determining the number of times the lid 3 is opened and the cumulative opening time, and changing the output and control constant in the heat insulation heating control, the rice is dried and the dew condensation at the lid 3 side, the opening of the pan 1, etc. Control can be performed.

  In addition, for the opening of the lid 3 during the rice cooking mode and the opening of the lid 3 for a long time during the heat retention mode, the display on the buzzer 125 such as a piezoelectric element mounted on the operation substrate 18 or the operation panel 14 Audible and / or visual warnings to help correct abnormal use.

  In addition, when it is determined that the lid 3 is open during the heat retention mode, the heating control for preventing the temperature of the rice from being lowered or preventing the drying at the surface portion of the rice against the fact that the lid 3 is opened. Can be changed.

  Further, when it is determined that the lid 3 is opened during the heat retention mode, it is determined that the temperature of the lid heater 6a is low, and overheating is caused by shifting to the temperature raising control, so the energization to the lid heater 6a is stopped. In addition, it is preferable to issue a warning in conjunction with this.

  Further, when it is determined that the lid 3 is opened during the heat retention mode, the lid 3 is suddenly cooled down by the outside air, and condensation is likely to occur immediately after the lid 3 is closed. Condensation can be prevented by increasing the energization rate of the cover heater 6a.

  Further, when it is determined that the lid 3 is opened during the heat retention mode, in addition to warning this, the energization to the lid heater 6a is stopped to avoid overheating, and the bottom heating source 4 and the side heating source 5 can be switched to heating control to ensure the quality of the rice as much as possible.

  Moreover, the heat insulation heating control which wraps a rice storage area at the same predetermined temperature from the three temperature information of the main sensor 34, the side sub sensor 121, and the lid sub sensor 123 can be performed, and ideal heat insulation can be performed. .

  On the other hand, rice cooking is generally performed by the process and temperature control as shown in FIG. 9, but it is customary to cool by the fan 13 in order to cool the heating coils 4 a 1, 4 a 2 and the IGBT in the bottom heating source 4. As shown in the example of FIG. 9, the fan 13 is turned off in the initial water temperature detection process so that the water temperature can be properly detected in a room temperature environment, and quietness and energy saving can be obtained. As necessary, the fan 13 is turned on and turned off to obtain as much silence and energy saving as possible.

  However, as shown in FIG. 8, in the control of selecting the non-insulation mode and the insulation mode after cooking rice, the pan 1 is used to prevent the quality deterioration of the rice due to the slow temperature decrease when selecting the non-insulation mode. Although the example of cooling was disclosed previously, in the steaming process that is a pre-process of the heat retention mode or the non-heat retention mode, the fan 13 is turned on as usual when the heat retention mode is selected, but it corresponds to the selection of the non-heat retention mode. Then, the fan 13 is stopped and the on / off control of the fan 13 is selectively used properly so as to suppress the temperature drop of the rice. Depending on the fan 13 being turned off, quietness and energy saving can be obtained. Each example shown in FIGS. 10 and 11 performs the same control.

  In the example shown in FIG. 10, the fan 13 can be changed in wind speed to two levels, for example, in the temperature rising process and the cooking process for controlling the high temperature range, when the room temperature is high and when the room temperature is low. The drive is switched between strong and weak so that it can be as quiet and energy efficient as possible.

  Further, in the example shown in FIG. 11, the wind speed of the fan 13 can be changed to two levels, such as a strong and weak level. In response to the difference in heat generation between the heating coils 4a1 and 4a2, the fan 13 is switched between strong and weak so as to obtain as low noise and energy saving as possible.

  The present invention is practically used in an electric rice cooker that employs a non-metallic pan, and while maintaining the heat storage and heat retaining properties of the pan, the temperature control around the rice storage area is achieved without the influence of low monitoring of rice temperature due to low thermal conductivity. Appropriate heat insulation can be achieved without impairing the quality of the rice.

It is sectional drawing in the front-back direction which shows one example of the electric rice cooker which concerns on embodiment of this invention. It is sectional drawing in the left-right direction of the electric rice cooker of FIG. It is detail sectional drawing around the opening part of a pan. It is an Example figure of the heat generating body of a bottom part heating source. It is an installation condition figure of the thermocouple which detects the natural temperature fall state of rice. It is a graph which shows the detection result of the temperature fall state following the temperature rise state at the time of rice cooking by the thermocouple of FIG. It is explanatory drawing which shows the relationship of the item relevant to the heat retention control with the rice cooker of FIG. It is a flowchart which shows the heat retention control example in the rice cooker of FIG. It is a graph which shows one control example and temperature change with the rice cooker and fan drive in the rice cooker of FIG. It is a graph which shows another example of control and temperature change with rice cooking in the rice cooker of FIG. 1, and fan drive. It is a graph which shows the other example of control and temperature change with the rice cooker and fan drive in the rice cooker of FIG. It is explanatory drawing which shows the example of installation of the thermocouple which monitors the temperature change of the 100 size type rice in the heat retention control by the conventional system with the rice cooker using a clay pot. It is explanatory drawing which shows the installation example of the thermocouple which monitors the temperature change of the 150 size type rice in the heat retention control by the conventional system with the rice cooker using a clay pot.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pan 2 Main body 3 Cover body 4 Bottom part heating source 4a, 4a1, 4a2 Heating coil 4b, 4b1, 4b2 Heat generating body 5 Side part heating source 5a Thermal insulation heater (upper stage, middle stage, lower stage)
6 Lid Heating Source 6a Lid Heater 11 Interior Case 12 Exterior Case 13 Fan 34 Main Sensor 112 Operation / Control Board 121 Side Sub Sensor 122 Room Temperature Sensor 123 Lid Sub Sensor

Claims (5)

A non-metallic heating source at the bottom of the pan is a bottom heating source for inductively generating heat by an alternating magnetic field from the heating coil on the main body side that houses the pan, and side heating provided to heat the body of the pan on the main body side. Source, lid heating source provided on the lid side to close the pan,
A main sensor provided on the main body side to detect the temperature of the bottom of the pan, a side sub sensor provided on the main body side together with the side heating source, a lid sub sensor provided on the lid side together with the lid heating source,
An electric rice cooker that cooks and keeps warm,
In the heat retention mode, the lid heating source is moved with respect to the set value of the lid sub sensor, the side heating source is moved with respect to the set value of the side sub sensor, and the bottom heating source is set with respect to the set value of the main sensor. An electric rice cooker characterized by performing heat insulation heating control by reacting with a side heating source. There are three side heating sources, an upper stage, a middle stage, and a lower stage. The lid heating source, the side heating source upper stage, the side heating source middle stage and the lower stage are less than or equal to the set value of the main sensor for the target temperature. The electric rice cooker of Claim 1 which performs heat insulation heating control by changing an electricity supply capacity | capacitance in three units. The electric rice cooker of any one of Claims 1 and 2 which performs the heat retention heating control which maintains the temperature balance of the whole rice storage area by the three detected temperature information by a lid sub sensor, a side sub sensor, and a main sensor. The electric rice cooker of any one of Claims 1-3 which performs heat insulation heating control at the predetermined time from rice cooking. The electric rice cooker of Claim 4 which performs the condensation control corresponding to the dew condensation which prevents the dew condensation of a rice storage area from rice cooking to the predetermined time.

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