JP2010110488A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker whose temperature detection precision is improved and rice cooking performance is improved by reducing temperature inaccuracy peculiar to an infrared ray sensor due to the temperature variation of itself. <P>SOLUTION: The rice cooker includes a heating means 6 for heating a pot 3 equipped in a rice cooker body 2, a lid 4 for covering the rice cooker body, the infrared ray sensor 10 for detecting infrared rays emitted from the pot 3, a control means for controlling the heating amount of the heating means 6 according to temperature information of the pot detected by the infrared ray sensor 10, and a temperature adjustment means 12 for adjusting the ambient temperature of the infrared ray sensor. By adjusting the temperature to a prescribed temperature by the temperature adjuster, the temperature variation of the sensor itself is suppressed and the temperature inaccuracy of the infrared ray sensor due to transitional or regular temperature change is reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rice cooker configured to perform rice cooking control by detecting the temperature of a pan or the like with infrared rays.

  Conventionally, in infrared sensors such as thermopiles and thermistor bolometers, the temperature difference between the temperature measurement object and the infrared sensor and the absolute temperature of the infrared sensor itself are measured using the principle of heat reception due to the temperature difference between the temperature measurement object and the infrared sensor. Temperature measurement.

  When the temperature of the infrared sensor itself is stable, the temperature difference can be accurately measured, and the measured temperature accuracy can be maintained.

  However, in an environment where the temperature of the infrared sensor itself fluctuates greatly, as shown in FIG. 5, measurement errors due to the occurrence of temperature differences inside the sensor in the regions 501 and 502, which are transient states of temperature fluctuation, are caused. Arise.

  In addition, even if the temperature of the sensor itself is steady and stable, a measurement error occurs between the regions 503, 504, and 505 in which the absolute value of the temperature has changed.

  This is because the measurement accuracy is adjusted while keeping the ambient temperature of the sensor constant, and the accuracy decreases when the ambient temperature deviates from the measurement accuracy.

  These are prominent in infrared sensors used for rice cookers, cooking appliances, etc., in which the sensor itself is heated by radiant heat, convection heat or the like from an object to be heated such as a pan.

  An infrared sensor for correcting a temperature difference generated in the sensor in a transient state of temperature fluctuation, which is one of the above problems, has been considered (for example, see Patent Document 1).

  FIG. 6 shows a structure of a thermopile type temperature sensor for correcting a temperature difference that can be generated inside a conventional sensor. In this thermopile type temperature sensor, a cavity 102 is formed at the center of a frame-shaped heat sink 101 formed of a Si substrate. A thermal insulating thin film 103 is formed on the upper surface of the cavity 102.

  The thermal insulating thin film 103 is formed of Si02, SiN, or the like, and has a thickness of several microns in order to reduce the heat capacity.

  In the half region on one side of the heat sink 101 and the thermal insulating thin film 103, the first thermoelectric material 104 and the second thermoelectric material 105 are alternately wired over the upper surface of the heat sink 101 and the upper surface of the thermal insulating thin film 103, The first and second thermoelectric materials 104 and 105 are joined to provide a thermocouple cold junction 106, and the first and second thermoelectric materials 104 and 105 are joined to the upper surface of the thermal insulating thin film 103 to provide a thermocouple hot junction 107. As a result, a thermopile 108 for temperature measurement in which thermocouples are connected in series is formed.

  Electrodes 109 are provided at both ends of the thermopile 108 for temperature measurement.

In the other half region of the heat sink 101 and the heat insulating thin film 103, the first thermoelectric material 104 and the second thermoelectric material 105 are alternately wired between the upper surface of the heat sink 101 and the upper surface of the heat insulating thin film 103. The first and second thermoelectric materials 104 and 105 are joined to provide a thermocouple cold junction 110, and the first and second thermoelectric materials 104 and 105 are joined on the upper surface of the thermal insulating thin film 103 to form a thermocouple hot junction 111. Thus, a thermopile 112 for temperature correction in which thermocouples are connected in series is formed.

  Electrodes 113 are provided on both ends of the thermopile 112 for temperature correction.

  The thermopile 108 for temperature measurement and the thermopile 112 for temperature correction formed on the heat sink 101 and the heat insulating thin film 103 in this way are the same line width by the same first thermoelectric material 104 and the same second thermoelectric material 105, respectively. They are formed in symmetrical patterns with the same line length.

  Further, the region provided with the hot contact 107 for temperature measurement on the thermal insulating thin film 103 is covered with an infrared absorber 114 made of metal black such as Au or Bi.

  However, the infrared rays emitted from the measurement object are absorbed by the infrared absorber 114 formed on the hot junction 107, and a temperature difference is generated between the cold junction 106 and the hot junction 107 formed on the heat sink 101, thereby measuring the temperature. An electromotive force is generated between the electrodes of the thermopile 108 for use.

  In addition, since the infrared absorber 114 is not formed on the thermopile 112 for temperature correction, no electromotive force is generated even when infrared rays are irradiated in a steady state.

  However, when a sudden temperature difference occurs in the ambient temperature, a temperature difference occurs between the heat insulating thin film 103 and the heat sink 101.

  In this case, in the thermopile 108 for temperature measurement, an electromotive force is generated due to the temperature difference between the thermal insulating thin film 103 and the heat sink 101 in addition to the electromotive force due to infrared absorption. The electromotive force due to the temperature difference between the thermal insulating thin film 103 and the heat sink 101 is the temperature. Since the same occurs in the thermopile 112 for correction, the difference between the temperature obtained from the thermopile 108 for temperature measurement and the temperature obtained from the thermopile 112 for temperature correction is obtained, so that the thermal insulating thin film 103 and the heat sink 101 An accurate temperature difference (temperature difference between the hot junction 107 and the cold junction 106) can be obtained without depending on the temperature difference.

In particular, by making the thermopile 108 and 112 the same thermoelectric material and structure, and taking the difference between the output of the thermopile 108 for temperature measurement and the output of the thermopile 112 for temperature correction, only the output by infrared absorption can be obtained.
Japanese Patent Laid-Open No. 11-258040

  However, in the conventional configuration, it is possible to increase the accuracy in the transient states 501 and 502 in which the sensor temperature changes rapidly among the temperature changes of the sensor itself shown in FIG. Even if the steady state is stable, the temperature measurement accuracy deteriorates between the regions 503, 504, and 505 in which the absolute value of the temperature has changed.

  This is because the measurement accuracy is adjusted with the ambient temperature of the infrared sensor constant, and there is a problem that the accuracy decreases when the ambient temperature deviates therefrom.

  The present invention solves the above-mentioned conventional problems, and stabilizes the temperature of the infrared sensor itself by adjusting the ambient temperature of the infrared sensor so that a transient and steady temperature change does not occur. It aims at providing the rice cooker which improves rice cooking performance by improving temperature detection accuracy.

  In order to solve the conventional problems, the rice cooker of the present invention is configured to adjust the ambient temperature of the infrared sensor.

  As a result, the infrared sensor does not cause a transient or steady temperature change, so that the temperature detection accuracy of the infrared sensor is increased and the rice cooking performance can be improved.

  The rice cooker of the present invention is configured to adjust the ambient temperature of the infrared sensor, thereby stabilizing the ambient temperature of the infrared sensor so that the infrared sensor does not cause a transient or steady temperature change. Therefore, it becomes possible to reduce the temperature accuracy deterioration resulting from the temperature change of the infrared sensor itself, and the rice cooking performance can be improved.

  1st invention is the heating means which heats the pan equipped to the rice cooker main body, the cover which covers the said rice cooker main body, the infrared sensor which detects the infrared rays radiated | emitted from the said pan, and the said infrared sensor detected It comprises a control means for controlling the heating amount of the heating means according to the temperature information of the pan, and a temperature adjustment means for adjusting the ambient temperature of the infrared sensor, and the temperature accuracy deterioration due to the temperature change of the sensor itself The rice cooking performance can be improved.

  In the second invention, in particular, the temperature adjusting means of the first invention is a temperature adjusting device capable of adjusting the ambient temperature of the infrared sensor to a predetermined temperature, so that the temperature of the infrared sensor is always adjusted to a predetermined temperature, and the sensor itself. It is possible to reduce temperature accuracy deterioration due to the temperature change.

  In the third invention, in particular, the temperature adjusting means of the rice cooker of the first invention is a fan for blowing air, and the temperature can be stabilized by cooling the infrared sensor heated by radiant heat or the like with the fan. .

  In the fourth aspect of the invention, in particular, the temperature adjusting means of the rice cooker of the first aspect of the invention is configured with a cover that thermally shuts off the infrared sensor and the surroundings, and the temperature rise of the infrared sensor due to radiant heat or the like is reduced. To stabilize the temperature.

  In the fifth aspect of the invention, in particular, the cover of the fourth aspect of the invention uses a heat insulating material, so that the temperature rise of the infrared sensor due to radiant heat or the like is further reduced by heat insulation using the heat insulating material to stabilize the temperature. It is what I did.

  In the sixth aspect of the invention, in particular, the cover of the fourth or fifth aspect of the invention uses an infrared reflecting material, so that the temperature rise of the infrared sensor due to radiant heat is reduced by the infrared reflection of the cover, and the temperature is further increased. Can be stabilized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
In FIG. 1, the rice cooker of this Embodiment is accommodated in the substantially bottomed cylindrical rice cooker main body 2 which has arrange | positioned the protective frame 1 made from a nonmagnetic material, and the said protective frame 1, and contains the metal of a magnetic material. A pan 3, a lid 4 that opens and closes the opening of the rice cooker body 1, and a substantially disk-like metal that is attached to the inside of the lid 4 and is detachably attached to seal the opening of the pan 3, and a magnetic metal. The inner lid 5 includes a heating pot 6 that heats (heats) the pan 3 and the inner lid 5 by induction.

  The heating means 6 is provided on the outer surface of the protective frame 1 and is provided on the upper surface of the lid cover 7 made of magnetic material inside the lid 4 and the heating coils 6a and 6b corresponding to the bottom and side surfaces of the pan 3. It consists of an inner lid 5 and a corresponding heating coil 6c.

  As shown in FIG. 2, a through-hole 9 closed with a plate-shaped infrared transmitting material 8 is formed in the center of the bottom wall of the protective frame 1, and the infrared sensor 10 installed therebelow is contaminated with water, foreign matter. I try to protect it.

  And the infrared rays radiated from the pan 3 can be detected by the infrared detector 11 of the infrared sensor 10 through the infrared transmitting material 8.

  A temperature adjusting device 12 is arranged in the vicinity of the infrared sensor 10 so that the temperature of the infrared sensor 10 that changes in temperature by heat transfer such as the radiant and convection from the pan 3 and the heating means 6 can be adjusted to a predetermined temperature. ing.

  Accordingly, since the infrared sensor 10 does not cause a transient and steady temperature change, it is possible to reduce the temperature accuracy deterioration caused by the temperature change of the infrared sensor 10 itself.

  As the temperature control device 12, a Peltier element, a heater, and the like are conceivable. However, the temperature control device 12 is not limited to this as long as the purpose is achieved.

  And the infrared sensor 10 is arranged and configured at a position facing the substantially central portion outside the bottom surface of the pan 3, so that the acquisition temperature is more stable than the side of the pan where the water level fluctuates depending on the amount of rice cooking, and the water temperature can be easily controlled. It will be.

  Moreover, since the temperature measurement of the pan 3 is performed in a non-contact manner with the above configuration, it is possible to quickly detect the temperature without being influenced by the thermal conductivity and heat capacity of the member.

  Here, in the rice cooker main body 2, a control means 13 that performs drive control of each part and each device to perform rice cooking operation is installed.

  This control means 13 performs drive control of each part and each apparatus according to a user's instruction performed via the input operation part 14 provided in the lid 4, for example.

  That is, the control means 13 includes a heating control means 13 a for controlling the heating means 6, a pan temperature control means 13 b for controlling the temperature of the pan 3 by the infrared sensor 10, and an inner lid temperature sensor 15 for controlling the temperature of the inner lid 5. It is comprised by the lid temperature control means 13c.

  The lid 4 is pivotally attached to the rice cooker body 2 via a hinge shaft 16 and automatically opens by the action of a spring 17 by opening a buckle (not shown) that locks the closed state. Is set to open. Of course, it is needless to say that a braking means for applying a brake to the opening operation is provided in consideration of safety.

  A steam cylinder 18 is provided at a substantially central portion of the lid 4.

In order to discharge the steam in the pan 3 to the outside through the steam discharge port 19 of the steam cylinder 18, for example, a 0.5 cm ² steam port 20 is formed in the inner lid 5.

  An inner lid packing 21 made of an elastic body such as rubber is attached to the outer peripheral portion of the inner lid 5 in order to seal the pan 3.

  Inside the steam cylinder 17, there is a spherical magnet 22 that is movable. This magnet 21 is moved to the hinge shaft 16 side when the lid 4 is opened or when the rice or rice starch dissolves in water during cooking and passes through the steam cylinder 18. It moves so that this can be detected by the magnetic sensor 23.

  The input operation unit 14 arranged on the outer surface of the lid 4 is for displaying various information such as the menu and time for cooking rice, and for starting, canceling, and making reservations for cooking. The rice cooking program incorporated in the control means incorporated in the rice cooker body 2 is executed, and the heating means 6 is operated and stopped in accordance with the progress of the rice cooking program to carry out rice cooking.

  About the rice cooker comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, predetermined rice and water are set in the pan 3, the input operation part 14 is operated, a rice cooking menu is selected, and the rice cooking process is started by pressing the rice cooking start button.

  The rice cooking process is a dipping process in which water is kept at a constant temperature and the rice absorbs water, the cooking process in which the pot 3 is heated at once by the heating means 6 and the water in the pot is boiled, and the water in the pot 3 It consists of a steaming process that suppresses heating in the almost lost state. During these processes, rice is gelatinized and cooked.

  The control means optimally controls the heating means 6 according to the temperature of the pan 3 detected by the infrared sensor 10, and cooks rice according to a predetermined rice cooking program.

  There are several courses in the rice cooking program depending on the type of rice. When this steaming process ends, cooking rice ends, and the process automatically shifts to a heat retaining process, so that the temperature of the cooked rice does not decrease, and the user can always obtain warm rice.

  The detail of the operation | movement by rice cooking program execution is demonstrated below.

  When rice cooking is started, the soaking process is first started. The control means heats the pan 3 by the heating means 6, detects the temperature by the infrared sensor 10, adjusts the temperature to a temperature at which rice gelatinization does not start (less than about 60 ° C.), and promotes water absorption of the rice.

  If rice is made the highest temperature in the range where gelatinization does not start and the temperature is continued for a certain period of time (for example, 30 minutes to 2 hours), the water absorption rate tends to be improved.

  On the other hand, since the cooking time is often required to cook delicious rice in as short a time as possible, the pan 3 is raised to a temperature at which gelatinization does not start in a short time.

  However, when a contact temperature sensor such as a conventional thermistor is used, the temperature followability deteriorates due to a large influence on the heat capacity and thermal conductivity of the member, so when the sensor detects a temperature at which rice gelatinization does not start The actual temperature of the pan 3 may be raised further. As a result, gelatinization of the rice in contact with the pan 3 starts.

  In the present embodiment, the pan 3 by heating the pan 3 to 60 ° C. in the dipping process, the infrared sensor 10 that changes in temperature by heat transfer such as radiation from the heating means 6, convection, etc. By adjusting to, the infrared sensor 10 does not cause a transient or steady temperature change.

  Thereby, since the temperature accuracy deterioration resulting from the temperature change of the infrared sensor 10 itself can be reduced, the pan 3 can be accurately heated to a temperature at which rice gelatinization does not start.

  Further, even when the heating by the heating means 6 is stopped, in the conventional contact temperature sensor such as the thermistor, even if the temperature of the pan 3 starts to decrease, the temperature decreases for a certain time (for example, several tens of seconds to 1 minute) depending on the heat capacity of the sensor member. Without temperature tracking.

  On the other hand, in the present embodiment, by performing non-contact temperature detection by the infrared sensor 10, good temperature followability can be obtained regardless of the temperature rise and cooling of the pan 3.

  Therefore, even when the temperature of the pan 3 is maintained at a constant temperature (for example, 60 ° C.), it is immediately detected that the pan 3 has reached a constant temperature, the heating is stopped, and the temperature of the pan 102 falls below the constant temperature. Since this is detected immediately and heating is resumed, it is possible to perform a very close chopping operation, which makes it possible to heat the pan 3 more evenly, and in turn pulls the temperature of the food inside the pan 3 more evenly. can do.

  In the cooking process, water and heat are added to the rice to cause gelatinization. The control means operates the heating means 6 to rapidly heat the pan 3 to bring the water inside to the boiling state.

  When the water gradually disappears, the temperature of the pan 3 continues to rise above 100 ° C. from the heated part, and by detecting about 130 ° C., it is determined that there is no water, and heating by the heating means 6 is stopped. .

  Also in this case, in the embodiment of the present invention, the temperature followability is good, and the infrared sensor 10 is kept at a predetermined temperature and the temperature accuracy is maintained by operating the temperature adjusting device 12 so that the infrared sensor 10 does not change in temperature. Therefore, it is possible to accurately detect the temperature at which it is determined that water has run out (about 130 ° C in this case), the temperature margin for safety can be set small, and more heat is transferred to rice. It is possible to control the heating means 6 to give.

  In the steaming process, almost no water remains in the pan 3, and the inside of the pan 3 is kept in a high temperature state (about 100 ° C) while the excess water adhering to the rice is evaporated, and gelatinization is performed. Further progress.

  At this time, the control means operates the inner lid heating coil 6c while detecting the temperature of the upper space of the pan 3 with the inner lid temperature sensor 15, and continues to give heat to the rice, thereby promoting the progress of gelatinization. Let

  With the above configuration, the rice cooker of the present embodiment improves the temperature followability by detecting the non-contact temperature by the infrared sensor 10, and further operates the temperature adjustment device 12 so that the infrared sensor 10 does not cause a temperature change. In addition, it is possible to provide a rice cooker that maintains the infrared sensor 10 at a predetermined temperature, reduces temperature accuracy deterioration due to temperature change of the sensor itself, accurately controls the temperature of the pan 10, and improves rice cooking performance. Become.

(Embodiment 2)
FIG. 3 shows the second embodiment, and the same reference numerals are given to the same components as those in the configuration of FIG. 2 described above, and the specific descriptions of the first embodiment are used.

  In FIG. 3, a blower fan 24 is arranged so that the infrared sensor 10 can be cooled by blowing air.

  Thus, the temperature change is reduced by blowing and cooling the temperature of the infrared sensor 10 that rises due to heat transfer such as heat from the pan 3 and heating means 6 due to the rice cooking process, and its transient and steady state. Temperature change can be reduced.

  Here, the blower fan 24 may be shared with a cooling fan for a power device such as a control means.

(Embodiment 3)
FIG. 4 shows the third embodiment, and the same reference numerals are given to the components that perform the same operations as those of the configuration of FIG. 2 described above, and the specific descriptions of the first embodiment are used.

  In FIG. 4, the infrared sensor 10 is covered with a cover 25 so as not to increase in temperature due to heat transfer such as radiation or convection.

  At this time, a hole 26 is formed in the cover 25 so that the visual field of the infrared sensor 10 is not obstructed.

  This cover 25 suppresses the temperature rise of the infrared sensor 10 due to heat transfer such as radiation from the pan 3 and heating means 6 due to the rice cooking process, and reduces its transient and steady temperature change, thereby reducing its own temperature. It is possible to reduce temperature accuracy deterioration due to the change.

  Here, if the cover 25 is configured by using a material having a large heat capacity or a heat insulating material, the influence of heat transfer can be reduced, and the influence of radiant heat can be further suppressed by using an infrared reflecting material. It becomes.

  With the above configuration, the rice cooker of the present embodiment improves the temperature follow-up by non-contact temperature detection by the infrared sensor 10, and further, a material having a large heat capacity or a heat insulating material so that the infrared sensor 10 is unlikely to cause a temperature change. By covering the infrared sensor 10 with the cover 25 using an infrared reflecting material, the temperature change is suppressed small, temperature accuracy deterioration due to the temperature change of the sensor itself is reduced, and the temperature control of the pan 3 is accurately performed. This makes it possible to provide a rice cooker with improved rice cooking performance.

  As described above, the rice cooker according to the present invention reduces the temperature accuracy deterioration factor peculiar to the infrared sensor due to the temperature fluctuation of the sensor itself, and can be applied to other cooking appliances whose heating is controlled by the infrared sensor. it can.

Sectional drawing of the rice cooker side surface in Embodiment 1 of this invention Cross section of the main part of the rice cooker Sectional drawing of the principal part of the rice cooker in Embodiment 2 of this invention. Sectional drawing of the principal part of the rice cooker in Embodiment 3 of this invention. Explanatory drawing which shows the temperature change of the conventional infrared sensor itself Top view showing a conventional infrared sensor

Explanation of symbols

2 Rice cooker body 3 Pot 4 Lid 6 Heating means 10 Infrared sensor 12 Temperature control device 24 Blower fan 25 Cover

Claims (6)

According to the heating means for heating the pan equipped in the rice cooker body, the lid covering the rice cooker body, the infrared sensor for detecting the infrared radiation radiated from the pan, and the temperature information of the pan detected by the infrared sensor A rice cooker comprising: control means for controlling the heating amount of the heating means; and temperature adjusting means for adjusting the ambient temperature of the infrared sensor. The rice cooker according to claim 1, wherein the temperature adjusting means is a temperature adjusting device capable of adjusting an ambient temperature of the infrared sensor to a predetermined temperature. The rice cooker according to claim 1 or 2, wherein the temperature adjusting means is a fan for blowing air. The rice cooker according to claim 1, wherein the temperature adjusting means is a cover that thermally shields the infrared sensor and the surroundings. The rice cooker according to claim 4, wherein the cover is formed of a heat insulating material. The rice cooker according to claim 4 or 5, wherein the cover is formed of an infrared reflecting material.

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