JPS59137019A - Rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention relates to a rice cooker that is capable of detecting the boiling point of rice in an inner pot and controlling heating from high heat to medium heat at that point. be.

In conventional rice cookers, the boiling point of the rice in the inner pot was detected by detecting the temperature on the sides and bottom of the inner pot, and the rice heating was controlled accordingly. Because there is a rice cooker nearby, the temperature around the 9 periphery may shift, and if the temperature sensor and the inner pot are not in close contact, the boiling point may shift, and the temperature characteristics themselves are unstable, making it impossible to accurately detect the boiling point. There were drawbacks.

This invention was made to improve this drawback, and after a predetermined temperature is detected by the inner lid temperature sensor, high-heat heating is continued until a time corresponding to the amount of rice cooked has elapsed. This paper proposes a rice cooker that can optimally control rice cooking by controlling rice cooking from low to medium heat.

FIG. 1 is a sectional view of the rice cooker main body according to the present invention.

In the figure, 1 is an outer pot, and an inner pot 5 in which rice and water are placed is arranged. Reference numeral 8 denotes an outer lid, and an inner lid temperature detector 3 for detecting the temperature of the inner lid 9 is pressed downwardly by a spring 80 and pressed against the inner lid 9.

6 is a rice cooking heater disposed at the bottom of the outer pot 1, and 81 is a bottom temperature detector disposed in close contact with the bottom surface of the central portion of the inner pot 5.

FIG. 2 is an overall configuration diagram of an embodiment of the rice cooker according to the present invention.

As is clear from FIG. 2, this embodiment is equipped with a rice cooking heater 6 that heats the inner pot 5 from the bottom, and an inner lid temperature detector 3 that detects the temperature of the inner lid 9 that covers the top opening of the inner pot 5. ,
Based on the detection signal of the inner lid temperature detector 3, the rice cooking amount determining means 19 determines the amount of rice cooked in the inner pot 5, and based on this determination, the amount of rice to be heated thereafter is determined by the rice heating amount determining means 20, and this determination The heating amount of the rice cooking heater 6 is controlled by the heating amount control means 21 based on the output of the means 20.

Further, the boiling point is determined by the boiling point determination means 22 based on the detection signal of the inner lid temperature detector 3, and after a predetermined time is measured by the timer means 23 based on this determination, the heating amount determining means 20 is determined. is re-determined and the heating amount control means 2
1 is configured to switch the heating amount to high heat heating.

FIG. 3 is a circuit diagram showing the electrical connections of the embodiment shown in FIG. Memory 40, CPU 4
1. Input circuit 38. This is a control device that includes a microcomputer 42 that includes an output circuit 43.

24 and 25 are resistors connected in series with the temperature detectors 3 and 81, respectively, and the detection output of each is connected to the microcomputer 4.
The signal is inputted to the input circuit 38 via the No. 2 MU/D converter 39.

35.36.37 is the inner pot detection switch 16° and the rice cooking switch 17. A resistor is connected in series with the test switch 34, and its output is input to the input circuit 3B in the microcomputer 42.

The heating amount control means 21 includes a bidirectional thyristor 52 in series with the rice cooking heater 6. Resistance 48. Transistor 49 and resistor 44
and is connected to the output circuit 43. 51 is a heating AC power source.

Next, the operation of the above embodiment will be explained.

FIG. 4 is a flowchart showing the rice cooking program stored in the memory 40 of the microcomputer 42.

When the power is turned on, the microcomputer 42 starts to start up, and when the rice cooking switch 17 is pressed in step 66, rice cooking starts in step 67 with the heating amount of the rice cooking heater 6 set to the maximum. Then, in step 6, the inner lid temperature becomes higher than tl (for example, 40°C).
The microcomputer 42 counts the time T until the temperature reaches the temperature 15 (for example, 55° C.) in the 8th to 9th steps 69, and automatically determines the amount of cooked rice based on the counted time To (step 70).

Conventional rice cookers determine the amount of cooked rice based on the temperature rise rate of a temperature sensor that detects the temperature of the sides and bottom of the inner pot. Since heat is generated, the ambient temperature around the temperature sensor is high, and it is greatly affected by variations in contact between the temperature sensor and the side or bottom surface of the inner pot. When the contact area is small, a large temperature gradient occurs between the temperature sensor and the inner pot, and the actual temperature rise also shows a steep slope.On the other hand, when the contact area is large, the temperature gradient Become calm.

Therefore, it has the disadvantage of causing errors in determining the amount of rice to be cooked. However, in the present invention, since the inner lid temperature detector 3 installed in the lid part that does not have a high-temperature heating element nearby determines the amount of cooked rice by detecting the temperature rise of the inner lid 9, the inner lid temperature detector 3 and the inner lid temperature detector 3 are connected in the first place. The temperature distribution of the lid 9 is small, and even if the contact area between them changes, it will not be affected greatly.

Therefore, by determining the amount of cooked rice based on the temperature distribution of the inner lid temperature detector 3, the reliability of determining the amount of cooked rice can be significantly improved.

Although the present invention directly detects not only the temperature of the inner lid 9 but also the temperature of the steam generated from inside the inner pot 5, the same effect can also be obtained by detecting the temperature of other lid parts. Not even.

To further explain the rice cooking process with reference to FIGS. 4 and 5, the inner lid temperature reaches ts (step 69).

When the rice cooking amount determination is completed (step 70), the heating amount of the rice cooking heater 6 is determined so as to obtain high heat power corresponding to the rice cooking amount, and the rice cooking heater 6 is controlled to high heat in step 71.
), the high flame power control is continued until the inner lid temperature reaches 14 (for example, 82° C.) (step 72). This temperature t4 is the temperature of rice and water in the inner pot 5 of 9. It will eventually begin to boil, and this is the temperature used to detect this boiling point.

When cooking rice, it is best to let the rice absorb enough water, then heat it all at once over high heat to avoid uneven cooking, and once it has boiled, reduce the heat to medium enough to prevent the rice from boiling over and the temperature of the rice to drop. It is said to be good.

However, if the heat is weakened before the rice boils, the temperature of the rice in the inner pot will drop, and in some places the temperature will not rise completely, causing problems such as insufficient gelatinization of rice starch.

In the conventional method of detecting the temperature at the bottom or side of the inner pot 5, the temperature characteristics that clearly detect the boiling point of cooked rice are not clear, and the temperature sensor and the inner pot are not in contact with each other. It was difficult to always accurately determine the boiling point of rice due to variations in area and changes in the temperature rise curve of the temperature detector.

However, according to the present invention, the inner lid temperature detector 3 is in close contact with the inner lid 9 to detect the temperature of the inner lid 9, and the inner lid 9 is in close contact with the inner pot 5 to detect the temperature of the inner pot 5. At the same time as the water vapor is picked up, the water vapor evaporating from the inner pot 5 is also directly received, so a temperature rise can be detected more reliably.

In FIG. 5, when the temperature of the inner lid temperature detector 3 reaches t in step 72, in the present invention, the microcomputer 4 further sets the delay time T1 until the electric power is reduced to medium heat heating according to each amount of rice cooked. When the timing is completed (step 73), the heating amount of the rice cooking heater 6 is determined again.

The heating power is controlled by reducing the electric power from high heat heating to medium heat heating (step 74).

This 'r+ is empirical data determined by experiment, but in general, the larger the amount of rice cooked, the larger the TI.

As the rice cooking operation progresses, water runs out at the bottom of the inner pot 5, and the temperature at the bottom of the inner pot rises rapidly.The bottom temperature t6 (for example, 12
5° C.), based on the output from the bottom temperature detector 81, it is determined in the microcomputer 42 that the predetermined value has been exceeded, the transistor 49 is turned off, and the bidirectional thyristor 52 is kept off. Then, the rice cooking is completed (step 76).

As described above, according to the present invention, the amount of cooked rice and the boiling point are determined by detecting the inner lid temperature, and the appropriate amount of heating can be given based on the determination of the temperature. Inconveniences such as misjudging the boiling point can be avoided, and delicious rice can be cooked with an appropriate amount of heat. In addition, since a delay time is provided when switching the heating amount from high heat heating to medium heat heating, the boiling point can be determined reliably and is not affected by variations in contact area.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the rice cooker main body according to the present invention. FIG. 2 is an overall configuration diagram of an embodiment of the rice cooker according to the present invention,
FIG. 6 is a circuit diagram showing the electrical connection. FIG. 4 is a flowchart showing the operation, and FIG. 5 is a diagram for explaining the operation of one embodiment of the rice cooker according to the present invention. 5 is the inner pot, 3 is the inner lid temperature detector, 6 is the rice cooker, 8
1 is a bottom temperature detector, 42 is a microcomputer, 19 is a rice cooking amount determining means, 20 is a cooking rice amount heating determining means, 21 is a heating control means, 22 is a boiling point determining means, and 23 is a clocking means. Agent Shin Kuzuno - (1 other person) Figure 1

Claims (2)

[Claims] (1) A rice cooking heater that heats the inner pot from the bottom, an inner lid that covers the top surface of the inner pot, an inner lid temperature detector that detects the temperature of this inner lid, and a detection signal of this inner lid temperature detector as input, Rice cooking amount determining means for determining the amount of cooked rice in the inner pot by measuring the time required to pass through a predetermined temperature range, and rice cooking heating for determining the amount of subsequent heating based on the amount of cooked rice determined by the rice cooking amount determining means. amount determining means, heating amount control means for controlling the heating amount of the rice cooking heater based on the output of the rice cooking heating amount determining means, and boiling point determination means for determining the boiling point of the cooked rice using the detection signal of the inner lid temperature detector as input. and a timer for measuring a predetermined time after the boiling point is determined by the determining means. The rice cooking heating amount determining means re-determines the heating amount based on the timing completion output from the timing means, and the heating amount controlling means switches the heating amount from high heat heating to medium heat heating. Characteristic rice cooker. (2) The rice cooker according to claim 1, wherein the rice cooking amount determining means, the cooking rice heating amount determining means, the boiling point determining means, and the time measuring means are implemented by a microcomputer.