JP2673747B2 - rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker that automatically cooks rice.

[0002]

2. Description of the Related Art Normally, a rice cooker has a rice cooking capacity of 0.5 l.
Models are designed for four types of capacities, 1.0 l, 1.5 l, and 1.8 l, and a heating element (heater) having different rated power is used according to each capacity.

Then, the microcomputer is controlled to perform a rice cooking sequence corresponding to each rice cooking capacity.

In this microcomputer, there are four types of large-scale integrated circuits (LSI) programmed for each rice cooking capacity, and an LSI corresponding to each rice cooking capacity is mounted.

Alternatively, as shown in FIG. 7, in order to execute four types of programs for each capacity by one LSI, the control board 1 on which the LSI is mounted is provided with a capacity switching input port A,
Four types of resistance voltage division values are set by resistors R1 and R2,
The capacity was switched manually.

In the figure, 2 is a rice cooking heater, 3 is a heat retaining heater, 4 is an operation key, 5 is a rice cooking relay operated by turning on the operation key 4, 6 is a thermistor for detecting the temperature of the food, and 7 is A temperature fuse 8 is a heat-retaining triac for intermittently energizing the heat-retaining heater 3.

[0007]

In the above-mentioned prior art, when preparing four kinds of LSIs, there is a possibility that an LSI that does not correspond to the rice cooking capacity may be mounted on the rice cooker, and it is inspected whether the correct LSI is mounted. A process is required.
Moreover, one type of LS is required to manufacture four types of LSI.
The cost is higher than that of manufacturing I, and inventory control is required.

Further, in the case of the method of manually switching the program according to the capacity, there is a case where an incorrect selection is made and the program is misused, and a function for preventing misuse must be added.
High cost.

In view of the above, an object of the present invention is to provide a rice cooker capable of automatically switching the rice cooking sequence according to the rice cooking capacity.

[0010]

[Means for Solving the Problems] The means for solving the problems according to the present invention is, as shown in FIGS.
In a rice cooker equipped with, a current detector 10 that detects the current flowing through the rice cooker heater 2 at the start of rice cooking, and the rice cooking capacity is determined based on the output of the current detector 10 and a rice cooking sequence suitable for that capacity is executed. Rice cooker switching control device 1
1 and 1 are provided.

The current detector 10 is composed of a current transformer, the primary side of which is connected in series to the rice cooking heater 2 and the secondary side of which is connected to the rice cooking switching control device 11.

[0012]

In the above means for solving problems, when the rice cooking heater 2 is energized, the current flowing through the rice cooking heater 2 is detected by the current transformer 10 and converted into the secondary side voltage. This voltage is input to the rice cooking switching control device 11 from the input port B of the control board 1.

In the rice-cooking switching control device 11, the input voltage value is compared with four types of voltage ranges stored in advance for each capacity, and the rice-cooking capacity is determined.

Then, the rice cooking sequence having the determined rice cooking capacity is selected, and the rice cooking heater 2 is energized and controlled in accordance with the selected rice cooking sequence.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a control block diagram of a rice cooker showing an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram of the rice cooker, FIG. 3 is a cross-sectional view of the rice cooker, and FIG. Of FIG. 5, FIG. 5 is a primary side current waveform diagram according to the rice cooking capacity, and FIG. 6 is an LSI input voltage waveform diagram according to the rice cooking capacity.

The rice cooker has a rice cooking capacity of 0.5 l, 1.0.
There are four types of models different from 1, 1.5l, 1.8l,
Each model includes a rice cooking heater 2 and a warming heater 3 having different rated powers according to the rice cooking capacity.

The rice cooker of this embodiment determines the rice cooker capacity based on the output of the current detector 10 and the current detector 10 which detects the current flowing through the rice cooker heater 2 at the start of rice cooking. A rice cooking switching control device 11 for executing a suitable rice cooking sequence is provided.

The rice cooker comprises a cooker main body 12 and a lid 13 as shown in FIG. The cooker body 12 includes an outer case 14 and an outer pot 15. The outer pot 15 is attached to the outer case 14 via an upper ring 16. The rice cooking heater 2 is provided on the bottom surface of the outer pot 15, and the inner pot 17 is detachably inserted into the outer pot 15. As a result, the rice cooker is shown in FIG.
After the operation key 4 shown in is pressed, the heater 2 turns the inner pot 1
It is supposed to heat 7.

The inner pot 17 contains cooked food such as rice and water, and the thermistor 6 for detecting the temperature of the cooked product moves up and down on the lower surface of the bottom of the inner pot 17. It is provided freely.

As a result, in the rice cooker, the water content of the food to be cooked evaporates and disappears, and the bottom temperature of the inner pot 17 becomes 10
When the thermistor 6 detects that the temperature rises rapidly above 0 ° C., the end of cooking is determined.
In this way, the rice cooker is adapted to automatically perform the heating of cooked food to the end thereof.

A heat-retaining heater 3 is provided on the outer peripheral surface of the upper portion of the outer pot 15 to keep the cooked food warm.
The warming heater 3 is adapted to keep the food warm by being energized after the completion of cooking.

In FIG. 3, reference numeral 18 is a weight detector for detecting the weight of the food.

The current detector 10 comprises a current transformer 10 (current transformer), the primary side of which is connected in series to the rice cooking heater 2 and the secondary side of which is smoothed to the input port B of the control board 1 as shown in FIG. It is connected through the circuit 20. In FIG. 2, R3 and R4 are resistors.

The current transformer 10 converts the primary-side current flowing through the rice-cooking heater 2 into a secondary-side voltage, and the rice-cooking switching control device 1
Output to 1. Since the rice cooking heater 2 has a different rated power according to the rice cooking capacity, the voltage value output from the current transformer 10 varies depending on the rice cooking capacity as shown in FIGS.

The rice cooking switching control device 11 includes a control board 1
It is an LSI mounted on the board and is programmed with four types of rice cooking sequences according to rice cooking capacity. Then, the cooked rice switching control device 11 has a memory 21 in which four kinds of voltage ranges for the cooked rice heater 2 corresponding to each cooked rice capacity are stored in advance.
And a capacity discriminating means 22 for discriminating the rice cooking capacity by comparing the voltage value input from the current transformer 10 in which voltage range, and a program for executing a rice cooking sequence suitable for the discriminated rice cooking capacity. It is provided with a capacity-based rice cooking executing means 23 that is selected and executed.

In each rice cooking sequence, the constant number of the heating sequence during rice cooking is changed or the detected temperature is changed depending on the difference in the rated power of the rice cooking heater 2 to adjust the cooking up.

In the above structure, the operation key 4 is turned on, the rice cooking relay 5 is operated, and the rice cooking heater 2 is energized. When heating is started, the current flowing through the rice cooking heater 2 is detected by the current transformer 10 and converted into a secondary side voltage.
This voltage has its pulsation reduced when rectified into a direct current by the smoothing circuit 20, and is input from the input port B of the control board 1 to the rice cooking switching control device 11.

In the rice-cooking switching control device 11, the voltage value input by the capacity discriminating means 22 is compared with the four kinds of voltage ranges stored in the memory 21, and the rice-cooking capacity is discriminated.

Then, the rice cooking sequence of the rice cooking capacity determined by the capacity-based rice cooking execution means 23 is selected, and the rice cooking heater 2 is energized and controlled based on the detected temperature from the thermistor 6 in accordance with the rice cooking sequence.

After the cooking is completed, the heat retaining triac 8
As a result, the energization of the heat-retaining heater 3 is intermittent, and the food is kept warm at a constant temperature.

Therefore, by using one type of LSI programmed with a rice cooking sequence for a plurality of rice cooking capacities, the current detector 10 reads the primary side current flowing through the rice cooking heater 2 at the start of rice cooking, It is possible to automatically recognize the rice cooking capacity, switch the LSI program, and execute the rice cooking sequence suitable for each capacity.

As described above, it is not necessary to manufacture many kinds of LSIs for each rice cooking capacity as in the prior art, and one kind of LSI can be commonly used for rice cookers having different capacities, reducing the inspection process and simplifying inventory management. Can be planned.

Further, compared to the method of manually switching using one type of LSI, it is not misused, and therefore, it is not necessary to take measures for preventing misuse, and the cost is greatly improved as a whole. Can be lowered.

Moreover, by using the current transformer, the number of parts to be added to the rice cooker can be reduced, the versatility can be provided, and the LSI can be shared.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention.

[0036]

As is apparent from the above description, according to the present invention, the current detector for detecting the current flowing through the rice cooking heater according to the rice cooking capacity, and the rice cooking capacity is determined based on the output of the current detector. Since a rice switching control device that executes a rice cooking sequence suitable for that capacity is provided, it automatically recognizes the rice cooking capacity of the rice cooker and switches the LSI program to set the rice cooking sequence suitable for each capacity. Can be executed.

Thus, unlike the conventional case, it is not necessary to manufacture many kinds of LSIs for each rice cooking capacity, and one kind of LSI can be commonly used for rice cookers having different capacities, reducing the inspection process and simplifying inventory management. Can be planned.

Further, compared with the method of manually switching using one type of LSI, it is not misused, and therefore, it is not necessary to take measures for preventing misuse, and the overall cost is greatly reduced. Can be lowered.

Further, since the current detector is composed of a current transformer, the primary side of which is connected in series with the rice cooking heater and the secondary side of which is connected to the rice switching control device, there are few parts to be added to the rice cooker. Can be used for general purpose, LS
I can be shared.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a rice cooker showing an embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of the rice cooker.

FIG. 3 is a cross-sectional view of a rice cooker.

FIG. 4 is a flow chart when switching rice cooking sequences according to capacity.

FIG. 5 is a primary side current waveform diagram according to the rice cooking capacity.

FIG. 6 is a waveform diagram of an LSI input voltage according to a rice cooking capacity.

FIG. 5 is an equivalent circuit diagram of a conventional rice cooker.

[Explanation of symbols]

 2 Rice cooking heater 10 Current detector 11 Rice cooking switching control device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Nakatani, 22-22 Nagaikecho, Naganocho, Abeno-ku, Osaka-shi, Sharp Corporation (72) Emiko Fukuda, 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Sharp Corporation

Claims (2)

(57) [Claims] 1. A rice cooker having a rice cooking heater according to the rice cooking capacity, wherein the rice cooking capacity is determined based on the output of the current detector for detecting the current flowing through the rice cooking heater at the start of rice cooking. A rice cooker which is provided with a rice cooker switching control device for executing a rice cooker sequence suitable for the capacity. 2. The rice cooker according to claim 1, comprising a current transformer, a primary side of which is connected in series with a rice cooker heater and a secondary side of which is connected to a rice cooker switching control device. .