JPH0662955A - Rice boiler - Google Patents

Abstract

PURPOSE:To provide a rice boiler by which rice is boiled with good taste in a fixed time of heating independent of the amount of boiled rice, by a method wherein the amount of heating is regulated so that the change of temperature detected through an electromagnetic induction type inner vessel can be matched to an ideal temperature curve for boiling rice, which curve is previously stored. CONSTITUTION:A fixed amount of water 6 and rice 7 are put into an inner vessel 2 within a rice boiler body 1 and rice boiling begins to be started. A direct current produced by rectifying a commercial power 8 with a rectifier 9 is turned off and on by a switching element 13 and thus a microwave is produced. The microwave is applied to an induction-heating coil 12 and the inner vessel 2 is dielectrically heated. A means 16 detects a temperature by a thermal sensor 4, a means 24 detects the rate of a temperature rise and a means 25 determines the amount of boiled rice. On the other hand, a comparison between output from a storing means 22 for the rate of the temperature rise corresponding to toughness preset by a toughness-presetting means 21 and the rate thereof detected by the means 24 is made by a comparator 23. A presetting means 27 for the amount of heating controls the amount of heating for the heating coil 12, by presetting the amount of electric current on the basis of the amount of boiled rice and a temperature difference, and by regulating the duty ratio of the switching element 13 through an output-regulating means 15. In this way, boiled rice with favorite toughness is boiled approximately in a fixed time independent of the amount of boiled rice.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker, and more particularly to a rice cooker that induction-heats a rice cooker container by electromagnetic induction.

[0002]

2. Description of the Related Art An example of the configuration of a conventional rice cooker of this type is shown in FIG.
Shown in. In FIG. 7, e is a commercial AC power source, and H and S are a rice cooking heater and a relay switch connected in series to the AC power source e. The relay switch S comprises a coil Sc and a normally open contact Ss. When the coil Sc is excited, the contact Ss is kept closed and the rice cooking heater H is energized. AC power supply e
Supplies a constant power to the rice cooking heater H. Tr is a switching element, Vcc is a direct current constant voltage power source for driving, r is a protection resistor, and Mc is a microcomputer (hereinafter referred to as a microcomputer).

In the conventional rice cooker having such a structure, when rice cooking is started, the transistor Tr is turned on and off by a binary signal of the microcomputer Mc. When the transistor Tr is conducting, the relay switch S is turned on, and when it is not conducting, it is turned off. As a result, the microcomputer Mc controls the energization time of the rice cooking heater H to be turned on / off to cook rice.

[0004]

As described above, the conventional rice cooker has a structure in which the heating amount of the rice cooking heater H is controlled by the ON / OFF operation of the relay switch S. Therefore, since the rice is heated with a constant electric power from the start of cooking to the boiling, the heating time varies depending on the amount of cooked rice, and there is a difference in the cooked rice. In addition, the contact Ss is worn by the ON / OFF operation of the relay switch S to cause a failure, and it is impossible to precisely control the heating amount of the rice cooking heater H and the rice cooking accuracy cannot be improved. was there.

The present invention has been made to solve the problems of the conventional rice cooker, and the heating time is kept constant regardless of the change in the amount of cooked rice so that the amount of cooked rice accurately corresponds to the amount of cooked rice. In addition, the rice cooker is provided with a heating amount control means for performing heating while comparing the detected temperature of the temperature detector with an ideal rice cooking heating temperature.

[0006]

The present invention relates to a heating coil for inductively heating an inner pot, a current supply unit for supplying a high-frequency current to the heating coil, a temperature detecting unit for detecting a rice cooking temperature of the inner pot, and Temperature storage means for storing an ideal rice-cooking temperature curve of cooked rice in the kettle; temperature comparison means for comparing the rice-cooking temperature curve stored in the temperature storage means with the temperature detected by the rice-cooking temperature detecting means; A heating amount control means for controlling the heating amount for heating the inner pot by adjusting the amount of current supplied to the heating coil based on the comparison of the comparison means, and based on the comparison of the temperature comparison means by the heating amount control means. The rice cooker is configured to control the heating amount control unit so that the amount of current supplied from the current supply unit to the heating coil matches the temperature curve stored in the temperature storage unit.

Further, according to the present invention, a heating coil for induction heating the inner pot, a current supply means for supplying a high frequency current to the heating coil, and a temperature detecting means for detecting the rice cooking temperature of the inner pot.
Temperature storage means for storing an ideal rice-cooking temperature curve of the hardness of the rice cooked in the inner pot, rice-cooking temperature curve corresponding to the hardness of the rice stored in the temperature storage means, and detection of the temperature detection means The temperature comparing means for comparing the temperature and the heating amount controlling means for controlling the heating amount for heating the inner pot by adjusting the amount of current supplied to the heating coil are provided. Based on the comparison, a rice cooker that controls the heating amount control means to match the amount of current supplied from the current supply means to the heating coil with the ideal rice hardness temperature curve stored in the temperature storage means It is composed.

[0008]

When the pre-cooking rice is started and reaches the set temperature, the timer is started, and the elapsed time within a certain range of the rising rice cooking temperature is measured to obtain the temperature gradient. The amount of cooked rice is determined based on the obtained temperature gradient, and the amount of current supplied to the heating coil that induction-heats the inner pot is set.

On the other hand, the ideal rice cooking temperature curve with respect to the elapsed time of rice cooking is stored in the controller of the rice cooker. Then, the detected temperature detected by the temperature detector is compared with the stored curve showing the ideal rice cooking temperature curve at regular time intervals. As a result of the comparison, the heating amount control means decreases the amount of current supplied to the heating coil when the temperature difference is positive, and increases the amount of supplied current when the temperature difference is negative. As a result, ideal heating is added for a certain period of time according to the amount of rice cooked in the inner pot, and delicious rice is cooked.

In the same manner, the cooked rice proceeds while controlling the current amount by comparing the stored temperature curves of three levels of "normal", "soft" and "solid" with the temperature detected by the temperature detector. To do. The rice cooking operation is program-controlled along the ideal curve, and the rice cooked to the desired hardness is served in a bowl.

[0011]

【Example】

Embodiment 1 FIG. 1 is an explanatory view of the structure of an embodiment of the present invention, in which the constituent parts similar to those in FIG. In FIG. 1, 1 is a main body of a rice cooker. 2 is an inner pot that forms a rice cooking container, 3 is an inner lid, 4 is a temperature sensor such as a thermistor, 5
Is an operation unit. The inner pot 3 is made of a magnetic material and is housed in the main body 1 so that it can be taken out freely, and the temperature sensor 5 is elastically in contact with the bottom surface thereof. When the rice cooking is started, the temperature sensor 4 constantly detects the rice cooking temperature in the inner pot 2. Although not shown, the operation unit 5 is provided with a display means such as a liquid crystal display or an LED, and a touch key for setting input. 6 is water in the inner pot 2 and 7 is rice.

Reference numeral 8 is a commercial power source, 9 is a rectifier, 10 and 11 are capacitors, 12 is a heating coil, and 13 is a switching element. The AC current of the commercial power source 8 is rectified by the rectifier 9, smoothed by the capacitor 10, and the DC current is output to the output end. The capacitor 11 is connected in parallel with the heating coil to form a resonance circuit. Reference numeral 14 is an input current detecting means provided in the output circuit of the commercial power supply 8, and 15 and 16 are an output adjusting means and a temperature detecting means connected to the gate of the switching element 13 and the temperature sensor 4.

Reference numeral 20 is a microcomputer. 21 is a microcomputer 2
0 is a hardness setting means, 22 is a temperature rise rate storage means, and 23 is a temperature comparison means. The hardness setting means 21 determines the hardness of the cooked rice, for example, "soft" and "normal".
And "hardening" are set in 3 stages. Numerals 24 and 25 are temperature rise rate detecting means and a rice cooking amount determining means which are connected to the output side of the temperature detecting means 16 and have a timer and an arithmetic function. The cooked rice amount judging means 25 judges the cooked rice amount in the inner pot 3 from the rising rate of the cooked rice temperature detected by the temperature rising rate detecting means 24 within a certain period of time, that is, the temperature gradient. Further, the boiling detection means 26 detects the boiling point of the temperature detected by the temperature detection means 16.

Reference numeral 27 is an overheat amount setting means, and 28 is a current amount setting means. The temperature increase rate of the cooked rice temperature detected through the temperature sensor 4, the temperature detection means 16 and the temperature increase rate detection means 24 is the ideal rice cooked temperature previously stored in the temperature increase rate storage means 22 by the temperature comparison means 23. Compared to the curve. The comparison result of the temperature comparison means 23 is the heating amount setting means 27.
And the conduction time of the switching element 13 is controlled via the current amount setting means 28 and the output adjusting means 15.
Further, the detection signal of the input current detecting means 14 is outputted to the current amount setting means 28 and controlled to the heating amount set by the superheat amount setting means 27.

The operation of the rice cooker of the present invention having the above structure will be described below with reference to FIGS. 2 and 3. Pour the polished rice 7 and an appropriate amount of water 6 in the inner pot 2, close the inner lid 3, pull out the cord reel, and connect the plug to a 100V power outlet. Next, while watching the display on the display window of the operation unit 5 provided on the upper surface of the main body 1, the touch key is operated to set the meal time in advance.

At the start time of preheating corresponding to the time of the reserved meal, a timer is activated to start preheating, and the heating coil 12 is supplied to the heating coil 12 through the heating amount setting means 27, the current amount setting means 28 and the output adjusting means 15. 20-50KHZ
A high frequency current of a certain degree is applied. When energization is started, the heating coil 12 is excited by a high frequency to form a magnetic field around the heating coil 12, and the generated alternating magnetic flux is linked to the inner pot 2 to generate Joule heat due to an eddy current in the inner pot 2 of the magnetic material. The heat generated in the inner pot 2 by such an electromagnetic induction action starts heating the water 6 and the rice 7 inside.

As shown in FIG. 2, the amount of current supplied during the preheating is, for example, 10 A, and the temperature tx detected by the temperature sensor 4 and the set temperature ts of the temperature rise rate detecting means 24 are checked (FIG. 2). Steps S2 and S3). The set temperature ts is, for example, 30 ° C., and when the detected temperature tx = 30 ° C., the timing of the temperature rise rate detecting means 24 starts as shown in FIG. When the preliminary heating progresses and the detected temperature tx reaches the upper limit of 40 ° C., the timing operation is temporarily stopped.

Elapsed time τ of the detected temperature tx = 30-40 ° C.
The rice cooking amount determination means 25 determines the rice cooking amount V. The cooked rice amount judging means 25 calculates the elapsed time τ as 60,
40, 20, 20- (sec) are classified into 4 stages and compared. The determination result of the rice cooking amount determination means 25 is the overheat amount setting means 2
7 and the current amount of 10, 8, 6, 4 A is set in the current amount setting means 28 according to each of the above steps, as indicated by S7 to S13. In this way, cooked rice amount V
Is added to the water 6 and the rice 7 in the inner pot 2 to shift from the preheating to the full-scale rice cooking process.

On the other hand, the temperature rise rate storage means 22 stores in FIG.
An ideal cooked rice temperature curve (straight line) C for time T as shown in FIG. Then, when entering the rice cooking process,
The heating control operation shown in FIG. 5 by the temperature comparison means 23 starts again. The output current I0 at the start of the heating control operation is
For example, start at 8A. 30se after starting
When c is counted, the ideal temperature tc1 of the rice cooking temperature curve C
And the temperature tx1 detected by the temperature detecting means 16 is the temperature comparing means 23.
Compared with.

As a result of the comparison between the detected temperature tx1 and the ideal temperature tc1, when the detected temperature tx1 of the temperature detecting means 16 is high, the current amount setting means 28 outputs the current amount of the output current I0 = 8-1 = 7 (A). Is set. Further, the temperature comparison means 23 is tx1 <t
When compared with c1, the output current I0 = 9 is set (steps S8 and S9 in FIG. 5). Similarly, the correction operation by comparison every 30 seconds is continued, and the heating amount is controlled to the ideal rice cooking temperature curve C.

When the boiling detection means 26 detects 100 ° C. at the boiling point of the water 6 due to the progress of rice cooking accompanied with the heating control operation, the superheat amount setting means 27 lowers the current amount to, for example, 4A. When the water content in the inner pot 2 disappears due to boiling, the temperature rises sharply and the rice is cooked and heated twice after the end-of-cooking temperature is detected. After that, move to the Murashi process and cook the rice at the scheduled time.

FIG. 6 shows an ideal rice cooking temperature curve according to the hardness of cooked rice. Here, the degree of hardness is selected from three levels of "softness", "normal" and "hardness". Curves C1, C2 and C3 are "solid" respectively
And "normal" and "soft". The hardness of the rice is set in the hardness setting means 21 in advance by operating the operation unit 5 before starting the rice cooking. Then, when the rice cooking process after the determination of the rice cooking amount V is started, these curves C1, C2, C
Based on the ideal rice cooking temperature curve C as 3, the heating control is performed in the same operation as described above.

In the above embodiment, the amount of current for precooked rice and heating for full-scale rice cooking is set to 10 A and 8 A, and the amount of cooked rice is divided into four stages, and the time interval for checking heating control is 30 se.
Although the case of c has been described as an example, it is not necessarily limited to the values and classifications of these examples. Also, 30 ~
Although the cooked rice amount V was obtained at the time of 40 ° C., another temperature range may be used as long as it is a linear change portion. Further, the amount of cooked rice may be determined based on the temperature difference within a certain time, that is, any amount of cooked rice may be detected in relation to the temperature gradient during cooking rice.

[0024]

According to the present invention, a heating coil for inductively heating an inner pot, a current supplying means for supplying a high frequency current to the heating coil, a temperature detecting means for detecting a rice cooking temperature of the inner pot, and a rice cooked inside the inner pot. Comparing the temperature storing means for storing the ideal rice cooking temperature curve of the cooked rice, the temperature comparing means for comparing the rice cooking temperature curve stored in the temperature storing means with the detected temperature of the rice cooking temperature detecting means, and the temperature comparing means The heating amount control means for controlling the heating amount for heating the inner pot by adjusting the amount of current supplied to the heating coil based on the The rice cooker is configured to control the heating amount control unit so that the amount of current supplied to the heating coil matches the temperature curve stored in the temperature storage unit.

The present invention further comprises a heating coil for induction heating the inner pot, a current supplying means for supplying a high frequency current to the heating coil, and a temperature detecting means for detecting the rice cooking temperature of the inner pot.
Temperature storage means for storing an ideal rice-cooking temperature curve of the hardness of the rice cooked in the inner pot, rice-cooking temperature curve corresponding to the hardness of the rice stored in the temperature storage means, and detection of the temperature detection means The temperature comparing means for comparing the temperature and the heating amount controlling means for controlling the heating amount for heating the inner pot by adjusting the amount of current supplied to the heating coil are provided. Based on the comparison, a rice cooker that controls the heating amount control means to match the amount of current supplied from the current supply means to the heating coil with the ideal rice hardness temperature curve stored in the temperature storage means Configured.

Unlike the conventional rice cooker, the heating time does not vary depending on the amount of cooked rice, and the cooked rice can be cooked uniformly. In addition, since the on / off operation of the switch is not used, no failure such as wear of the contacts occurs. Further, since the heating is controlled to the ideal rice cooking temperature curve, the rice cooking accuracy can be improved.

Therefore, according to the present invention, the heating time is made constant regardless of the change in the amount of cooked rice so that the amount of cooked food can be accurately corresponded to the amount of cooked rice, and the hardness of the ideal cooked rice to suit the taste. It is possible to provide a rice cooker for cooking rice.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of an embodiment of the present invention.

FIG. 2 is a flow chart illustrating a rice cooking amount determination operation according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating a rice cooking operation according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a heating amount control operation according to an embodiment of the present invention.

FIG. 5 is a flowchart illustrating a heating amount control operation according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a control operation of the hardness of cooked rice according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram of a configuration of a conventional rice cooker.

[Explanation of symbols]

 1 Main body of rice cooker 2 Inner pot 4 Temperature sensor 5 Operation part 6 Water 7 Rice 8 Commercial power supply 12 Heating coil 13 Switching element 15 Output adjusting means 16 Temperature detecting means 20 Microcomputer 21 Hardness setting means 22 Temperature storage means 23 Temperature comparison means 24 Temperature Rise Rate Detection Means 25 Rice Cooking Amount Determination Means 26 Boiling Detection Means 27 Heating Amount Setting Means 28 Current Amount Setting Means

Claims (2)

[Claims] 1. A heating coil for inductively heating an inner pot, a current supply means for supplying a high frequency current to the heating coil, a temperature detecting means for detecting a rice cooking temperature of the inner pot, and rice cooked in the inner pot. Temperature storing means for storing an ideal rice cooking temperature curve of cooked rice, temperature comparing means for comparing the rice cooking temperature curve stored in the temperature storing means with the detected temperature of the rice cooking temperature detecting means, and the temperature comparing means. And a heating amount control means for controlling the heating amount for heating the inner pot by adjusting the amount of current supplied to the heating coil based on the comparison of the above. A rice cooker characterized in that the heating amount control means is controlled so that the amount of current supplied from the current supply means to the heating coil matches the temperature curve stored in the storage means based on the above. 2. A heating coil for induction heating the inner pot, a current supply means for supplying a high-frequency current to the heating coil, a temperature detecting means for detecting a rice cooking temperature of the inner pot, and rice cooked in the inner pot. Temperature storing means for storing an ideal rice cooking temperature curve of rice hardness, and comparing the rice cooking temperature curve corresponding to the rice hardness stored in the temperature storing means with the temperature detected by the temperature detecting means. The temperature comparison means is provided with a heating amount control means for adjusting the amount of current supplied to the heating coil to control the heating amount for heating the inner pot, and the heating amount control means allows the comparison of the temperature comparison means. On the basis of the above, the heating amount control means is controlled so that the amount of current supplied from the current supply means to the heating coil matches the ideal cooking rice temperature curve of rice hardness stored in the temperature storage means. Rice cooker.