JP3028983B2 - 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 having a water absorption step of keeping water at a temperature at which rice easily absorbs water for a certain time and efficiently absorbing water.

[0002]

2. Description of the Related Art It is generally known that rice cannot be cooked satisfactorily until the core unless cooked after sufficient water is absorbed in rice. This water absorption speed varies depending on the water temperature.
Water absorption is completed in about 90% in about a minute, and water is completely absorbed (saturated) in 2 hours. However, at a water temperature of 40 ° C., 90% of the water is absorbed in less than 10 minutes, so the higher the water temperature, the more efficiently the water can be absorbed. Even if the higher the water temperature, the better, but if the rice starts to gelatinize at 60 ° C or higher, the surface of the rice gelatinizes and the core cannot absorb water.
Must be less than.

In a conventional rice cooker (especially a recent microcomputer-controlled rice cooker), when the operation of starting rice cooking is performed in consideration of the above characteristics, a water absorption step (preheating cooking) of maintaining the water temperature at 40 to 50 ° C. and absorbing water is performed. After cooking rice (cook up)
And various inventions have been made to achieve this. Further, since the water absorption speed varies depending on the type of rice (cooked rice) such as white rice (sticky rice), sticky rice, brown rice, etc., an invention in which the predetermined temperature in the water absorption step is varied depending on the type of rice (Japanese Patent Publication No. 3-32362). See)
There are also inventions that further advance the conventional configuration.

[0004]

The heating means of the rice cooker heats the bottom of the inner pot, and the temperature of the rice cooked in the inner pot rises at the top of the heating means at the bottom. On the other hand, the temperature detecting means detects the temperature at the bottom of the inner pot, but differs from the temperature at the bottom of the inner pot on the upper surface of the heating means because it detects the temperature at the center without the heating means. When the predetermined temperature is constant, the lower the water temperature, the longer the time until the heating stop means operates. (The lower the water temperature, the longer it takes for the temperature to rise to a certain temperature.) As a result of the longer heating time, the temperature of the rice cooked on the upper surface of the heating means at the bottom of the inner pot becomes overheated and becomes 60 ° C.
There was a problem that became more. Therefore, this location is not sufficiently absorbed and is gelatinized, resulting in uneven cooking. The problem caused by the water temperature difference has not been solved even in a configuration in which the predetermined temperature is varied depending on the type of rice.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a temperature detecting means for detecting the temperature of cooked rice in contact with an inner pot, and heating the cooked food in the inner pot. Heating means, and a heating stop means for detecting that the temperature detected by the temperature detecting means has reached a predetermined temperature as a water absorption step, and outputting a stop signal to the heating means. A predetermined temperature determining means for determining a predetermined temperature in accordance with a detection output (initial water temperature) of the detecting means is provided, and control is performed such that a stop signal is output to the heating stopping means at the determined predetermined temperature.

[0006] The temperature difference between the bottom and the top of the inner pot is larger when the water temperature is lower, and it takes time to equalize the water temperature. The water absorption time determining means for determining the time is provided.

[0007]

According to the structure of the present invention, when the initial water temperature is low, the predetermined temperature is set low, the water absorption time is set long, and the bottom of the inner pot is prevented from being excessively heated and locally heated. The time required for the heat of the convection to reach the upper part by convection becomes longer, the water can be absorbed uniformly, and unevenness in the cooked state can be prevented. Conversely, when the initial water temperature is high, the predetermined temperature is set high, the water absorption time is set short, and water can be absorbed uniformly without wasting time.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a rice cooker according to one embodiment of the present invention. FIG. 2 is a functional configuration diagram of the rice cooker. FIG. 3 is a diagram showing a temperature characteristic and a heating state when rice is cooked by the rice cooker, in a case where the water temperature is high. FIG. 4 is a diagram showing a heating state in which the water temperature is low. In the figure, 1 is a main body, 2 is an inner pot, 3 is a temperature detecting means, 4 is a heating means, 5 is a control unit, 6 is a heating stop means, 7 is a predetermined temperature determining means, and 8 is a water absorption time determining means.

In the structure, an inner pot 2 for accommodating cooked rice is removably accommodated in a main body 1, a temperature detecting means 3 which comes into contact with the inner pot 2 to detect a temperature, and heats the inner pot. The heating means 4 is provided. A control unit 5 is provided inside the main body 1, and the temperature detection unit 3 is connected as an input and the heating unit 4 is connected as an output. The control unit 5 is provided with a heating stop unit 6 as a program of a microcomputer (not shown). The microcomputer also includes a predetermined temperature determining means 7 and a water absorption time determining means 8 as programs.

The operation will be described below. When the user puts cooked rice (washed rice and an appropriate amount of water) into the inner pot 2 and stores it in the main body 1, the temperature detecting means 3 is in contact with the center of the bottom of the inner pot 2 and the heating means 4 is in contact with the outer periphery of the bottom. . When a cooker switch (not shown) is operated, a start signal is sent to the controller 5.
When the microcomputer in the control section 5 receives this start signal, it takes in the detection output of the temperature detection means 3 as the initial water temperature.

Next, the predetermined temperature determining means 7 operates to determine a predetermined temperature according to the detected initial water temperature. In this embodiment, a predetermined temperature is a temperature obtained by adding a constant temperature to the initial water temperature. For example, if the constant temperature is 30 ° C., the initial water temperature is 18 ° C. and the temperature is 4 ° C.
8 ° C., and 35 ° C. is determined as the predetermined temperature when the initial water temperature is 5 ° C.

Next, the water absorption time determining means 8 operates to determine the water absorption time according to the initial water temperature. This determination is obtained from the table data of Table 1 provided in the microcomputer. In the previous example, at an initial water temperature of 18 ° C., 14
In the case of an initial water temperature of 5 ° C., 18 minutes are obtained from Table 1 and determined as the water absorption time.

[0013]

[Table 1]

As described above, when the rice cooker switch is operated, the predetermined temperature and the water absorption time are instantaneously determined according to the initial water temperature. Next, the heating unit 4 starts heating according to a command from the control unit 5, and the water absorption step (preheating cooking) is started. 3 and 4
As shown in the figure, in the water absorption step, the heating amount of the heating means 4 is controlled to be low. Due to the heating, the temperature detected by the temperature detecting means 3 increases, and when the temperature reaches the determined predetermined temperature, the heating stopping means 6 operates to stop the heating of the heating means 4. Looking at the temperature rise characteristics during this time, when the water temperature is 5 ° C. (FIG. 4), it takes a longer time for the temperature to rise by heating because the water temperature is low compared to the case of the water temperature of 18 ° C. (FIG. 3). The upper layer of the temperature / water temperature of the stopping means 6 has a smooth inclination. On the other hand, since the water temperature immediately above the heating means 4 rises at substantially the same inclination, the difference between the temperature of the temperature detection means 3 and the water temperature immediately above the heating means 4 increases as the water temperature decreases.

For this reason, when the heating stop means 6 is operated at the same predetermined temperature as at 18 ° C. even when the water temperature is low as in the conventional 5 ° C. rice cooking example shown in FIG. Becomes very high, and gelatinization starts even though water has not been absorbed sufficiently yet. At low temperatures, the water absorption efficiency of rice is poor, but in FIG. 5, the water absorption time is constant and does not change.
It is not able to absorb enough water to cook delicious rice.

On the other hand, in the example shown in FIG. 4 according to the present invention, since the predetermined temperature is lowered in accordance with the water temperature, the heating stop means 6 is turned off in FIG.
It operates faster and does not have too high a water temperature.
Further, when the water temperature is low, the water absorption time is prolonged, so that the poor water absorption efficiency can be compensated and sufficient water can be absorbed.

In this embodiment, if the temperature detected by the temperature detecting means 3 falls below a predetermined temperature after the initial operation of the heating stopping means 6, the heating is restarted again. When the temperature reaches, the heating stop means 6 is operated again. When the predetermined water absorption time elapses, the water absorption process ends, the heating means 4 starts heating regardless of the heating stop means 6, and rice cooking starts. When the rice inside the inner pot 2 absorbs water and runs out of water, the temperature at the bottom of the inner pot rises rapidly, and this is detected by the temperature detecting means 3 to finish the rice cooking.

[0018]

As described above, according to the structure of the present invention, the predetermined temperature of the heating stop means and the water absorption time are appropriately changed depending on the initial water temperature, so that the water can be absorbed evenly regardless of the initial water temperature. It is possible to provide deliciously cooked rice with less uneven cooking.

In the present embodiment, both the predetermined temperature and the water absorption time are changed so as to obtain the most effect. However, the predetermined water temperature may be changed at the initial water temperature.

Although a predetermined temperature is added to obtain the predetermined temperature and the water absorption time from the initial water temperature, the method of obtaining the predetermined temperature is not limited to this embodiment.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rice cooker according to one embodiment of the present invention.

FIG. 2 is a functional configuration diagram of the rice cooker.

FIG. 3 is a diagram showing temperature characteristics and a heating state when rice is cooked by the rice cooker, in a case where a water temperature is high.

FIG. 4 shows a case where the water temperature is low.

FIG. 5 is a diagram showing temperature characteristics and a heating state when rice is cooked under the same conditions as in FIG. 4 using a conventional rice cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Inner pot 3 Temperature detecting means 4 Heating means 6 Heating stopping means 7 Predetermined temperature determining means 8 Water absorption time determining means

Claims (1)

(57) [Claims] 1. A main body (1), an inner pot (2) housed in the main body (1), temperature detecting means (3) abutting on the inner pot (2) to detect the temperature of cooked rice, A heating means (4) for heating the cooked rice in the kettle (2) and a stop signal is output to the heating means (4) upon detecting that the temperature detected by the temperature detecting means (3) has reached a predetermined temperature. A predetermined temperature determining means (7) for determining a predetermined temperature in accordance with a detection output of the temperature detecting means (3) at the time of starting rice cooking, and detecting the temperature at the time of starting rice cooking. Water absorption time determining means (8) for determining the water absorption time in accordance with the detection output of the means (3) is provided, and when the temperature detecting means (3) detects the predetermined temperature determined by the predetermined temperature determining means (7). The heating stop means (6) outputs a stop signal to the heating means (4), and further, the water absorption time determining means The rice cooker characterized in that the heating stop means (6) outputs a stop signal at the predetermined temperature for the water absorption time determined by (8).