JP3214728B2 - Rice cooker control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for a rice cooker mainly used at home.

[0002]

2. Description of the Related Art In recent years, a rice cooker has been controlled using a microcomputer so that dew sticking to the inner lid of the rice cooker is eliminated so that the rice cooker is not exposed.

Conventionally, a control circuit of this type of rice cooker has a configuration as shown in a block diagram of FIG. Hereinafter, the configuration will be described with reference to FIG.

[0004] As shown in FIG. 4, reference numeral 1 denotes a pot for putting rice to be cooked and water, etc., 2 denotes an inner lid located above an opening of the pot 1, 3.
Is a main heating means for heating the pot 1 at the time of cooking rice, 4 is a heating means for heating the pot 1 at the time of keeping the heat, 5 is a lid heating means for heating the inner lid 2, and 6 is a pot temperature detecting means for detecting the temperature of the pot 1. , 7
Is a lid temperature detecting means for detecting the temperature of the inner lid 2, and 8 is a control means which is constituted by a microcomputer. When the warming step is started from the rice cooking process, both the pot temperature detecting means 6 and the lid temperature detecting means 7 are used. The output is input and output to the main heating means 3, the thermal insulation heating means 4, and the lid heating means 5 to control the temperature of the pot 1 and the temperature of the inner lid 2 in accordance with the thermal insulation sequence.

[0005] The operation of the control means 8 of the conventional rice cooker in the above configuration will be described with reference to the flowchart shown in FIG. In step (hereinafter abbreviated as S) 10, control means 8
Inputs the outputs of both the pot temperature detecting means 6 and the lid temperature detecting means 7 and outputs them to the main heating means 3, the heat retaining heating means 4 and the lid heating means 5, and the temperature of the pan 1 and the inner lid 2 is controlled according to the rice cooking sequence.

Next, the process proceeds to S11. In S11, the control means 8
Determines whether the rice cooking process has been completed. If not, the process returns to S10 to continue the rice cooking process. When the process is completed, the process proceeds to S12. In S12, the control means 8 determines whether the temperature θ of the pan 1 is equal to or higher than the heat retention temperature θ1 based on the output of the pan temperature detecting means 6. In the state immediately after entering the heat retaining step from the rice cooking step, since the temperature θ of the pot 1 is higher than the heat retaining temperature θ1, the process proceeds to S13. In S13, the control means 8 determines whether the temperature φ of the inner lid 2 is equal to or higher than φ1 based on the output of the lid temperature detecting means 7. The value of φ1 is set so as not to exceed the heat resistant temperature of the lid heating means 5.

When the temperature φ of the inner lid 2 is equal to or higher than φ1 in S13,
Proceed to S14. In S14, the control means 8 controls the lid heating means 5 to stop heating the inner lid 2. In S13, the temperature φ of the inner lid 2
Is smaller than φ1, the process proceeds to S15. In S15, the control means 8
Controls the lid heating means 5 to heat the inner lid 2. Note that S
In steps S14 and S15, the control means 8 controls the heat retaining / heating means 4 to stop heating the pot 1. The process returns to S12 from S14 and S15.

[0008] It takes a long time for the temperature θ of the pot 1 to become lower than the heat retention temperature θ1 from the rice cooking process to the heat retention process, and during that time, S12 to S14 and S15 are repeated. If a long time elapses after the rice cooking process enters the heat retaining process in S12, the temperature θ of the pot 1 becomes lower than the heat retaining temperature θ1, and the process proceeds to S16. In S16, the control means 8 determines whether the temperature θ of the pan 1 is equal to or higher than the heat retention temperature θ1 based on the output of the pan temperature detecting means 6. Pot 1
If the temperature θ is equal to or higher than the heat retention temperature θ1, the process proceeds to S17. S17
Then, the control means 8 controls the heat retaining / heating means 4 and the lid heating means 5 to stop heating the pot 1 and the inner lid 2.

If the temperature θ of the pot 1 is lower than the heat retaining temperature θ1 in S16, the process proceeds to S18. In S18, the control means 8 determines whether the temperature φ of the inner lid 2 is equal to or more than φ1 based on the output of the lid temperature detecting means 7. When the temperature φ of the inner lid 2 is lower than φ1 in S18, the process proceeds to S19. In S19, the control means 8 controls the heat retaining / heating means 4 and the lid heating means 5 to heat the pot 1 and the inner lid 2.
When the temperature φ of the inner lid 2 is equal to or more than φ1 in S18, the process proceeds to S20.
In S20, the control means 8 controls the heat retention / heating means 4 and the lid heating means 5
Are controlled to keep the pot 1 warm, and the heating of the inner lid 2 is stopped.

[0010] From S17, S19 and S20, return to S16,
From 16, the operations of S17, S19, and S20 are repeated. With the above operation, dew sticking to the inner lid 2 of the rice cooker is eliminated, and the dew receiving of the rice cooker is eliminated.

[0011]

In such a conventional rice cooker control circuit, it takes a long time for the temperature of the pot to become lower than the heat retaining temperature from the rice cooking process to the heat retaining process, and the inner lid is heated. There is a problem that the time becomes longer and the power consumption increases.

[0012] The present invention solves the above-mentioned problems, and the temperature of the pot is lower than the heat retaining temperature when the warming process is started from the rice cooking process.
The control circuit of the rice cooker that can keep the temperature lower than the heat retention temperature by cooling the pan until it becomes short, shorten the time to heat the inner lid, and keep the heat with no power consumption and no dew on the inner lid. It is intended to provide.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a pot for putting rice to be cooked and water, an inner lid located above an opening of the pot, and a pot for cooking rice. Main heating means for heating the pan, a heat retaining heating means for heating the pan during heat retention, a lid heating means for heating the inner lid, a pan temperature detecting means for detecting the temperature of the pan, and a temperature of the inner lid. Lid temperature detecting means for detecting, pot cooling means for cooling the pot, and the temperature of the pot is kept warm when the warming step is started from the rice cooking process.
Output to the pan cooling means until the temperature drops below , cool the pan, input both outputs of the pan temperature detection means and the lid temperature detection means, the main heating means, the heat insulation heating means, And control means for outputting to the lid heating means and controlling the temperature of the pan and the temperature of the inner lid in accordance with a heat retention sequence.

[0014]

According to the present invention, the control means inputs both outputs of the pot temperature detecting means and the lid temperature detecting means, and enters the warming process from the rice cooking process, and cools the pot until the temperature of the pot falls below the warming temperature. Controlling the means to cool the pan, shortening the time when the temperature of the pan is lower than the keeping temperature, shortening the time for heating the inner lid, controlling the main heating means, the keeping heating means and the lid heating means Insulate the inner lid with low power consumption and no dew.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram of the control circuit.
, 9 is a pan cooling means for cooling the pan 1, a control means 8
When entering the warming process from the rice cooking process, outputs to the pot cooling means 9, cools the pot 1, inputs both outputs of the pot temperature detecting means 6 and the lid temperature detecting means 7, and outputs the main heating means 3, The temperature is output to the heat retaining heating means 4 and the lid heating means 5 and the temperature of the pan 1 and the inner lid 2 are output.
Is controlled according to a heat retention sequence.

FIG. 2 is a specific circuit diagram of FIG.
In Fig. 2, the main heating means 3 for heating the pot 1 during cooking rice is composed of a heater 3a for heating the pot 1, a relay contact 3b, a relay coil 3c, a transistor 3d, and a resistor 3e.

Here, one terminal of the heater 3a is connected to an AC power source 1
The other terminal of the heater 3a is connected to one side of a relay contact 3b. Further, the other terminal of the relay contact 3b is connected to the other terminal of the AC power supply 10. One terminal of the coil 3c of the relay is
Is connected to a DC power supply 11 for inputting the AC voltage and outputting a DC voltage, the other terminal of the coil 3c of the relay is connected to the collector of the transistor 3d, and the emitter of the transistor 3d is connected to the ground. Transistor 3d
Is connected to one terminal of the resistor 3e and the output terminal of the microcomputer 8 constituting the control circuit.
The other one-side terminal of e is connected to the DC power supply 11.

Heating and heating means 4 for heating the pot 1 during heat insulation
Is composed of a heater 4a for heating the pan 1, a bidirectional three-terminal thyristor 4b, a resistor 4c, a transistor 4d, and a resistor 4e. One terminal of the heater 4a is connected to one side of the AC power supply 10, and the other terminal of the heater 4a is connected to the T2 terminal of the bidirectional three-terminal thyristor 4b. Further, the T1 terminal of the bidirectional three-terminal thyristor 4b is connected to the other side of the AC power supply 10. One terminal of the resistor 4e is the AC power supply 1
DC power supply 11 that inputs 0 AC voltage and outputs DC voltage
The other terminal of the resistor 4e is connected to the base of the transistor 4d and the output terminal of the microcomputer 8, and the emitter of the transistor 4d is connected to the ground. The collector of the transistor 4d is connected to one terminal of the resistor 4c, and the other terminal of the resistor 4c is connected to the gate terminal of the bidirectional three-terminal thyristor 4b.

The lid heating means 5 for heating the inner lid 2 comprises:
5a, a bidirectional three-terminal thyristor 5b, a resistor 5c, a transistor 5d, and a resistor 5e.
One terminal of the heater 5a is connected to one side of the AC power supply 10, and the other terminal of the heater 5a is connected to the T2 terminal of the bidirectional three-terminal thyristor 5b. Further, the T1 terminal of the bidirectional three-terminal thyristor 5b is connected to the other side of the AC power supply 10. One terminal of the resistor 5e is connected to a DC power supply 11 for inputting the AC voltage of the AC power supply 10 and outputting a DC voltage, and the other terminal of the resistor 5e is connected to the base of the transistor 5d and the output terminal of the microcomputer 8. Connected
The emitter of the transistor 5d is connected to the ground. The collector of the transistor 5d is connected to one terminal of the resistor 5c, and the other terminal of the resistor 5c is connected to the gate terminal of the bidirectional three-terminal thyristor 5b.

Pan temperature detecting means 6 for detecting the temperature of pan 1
Is a thermistor 6a for detecting the temperature of the pan 1, a resistor 6b, A
/ D converter 6c. One terminal of the thermistor 6a is connected to the DC power supply 11, and the other terminal of the thermistor 6a is connected to one side of the resistor 6b and the input terminal of the A / D converter 6c. The other terminal on one side of the resistor 6b is connected to the ground, and the output of the A / D converter 6c is connected to the input terminal of the microcomputer 8.

A lid temperature detecting means 7 for detecting the temperature of the inner lid 2
Are a thermistor 7a for detecting the temperature of the inner lid 2, a resistor 7b,
It is composed of an A / D converter 7c. One terminal of the thermistor 7a is connected to the DC power supply 11, and the other terminal of the thermistor 7a is connected to one side of the resistor 7b and the input terminal of the A / D converter 7c. The other terminal on one side of the resistor 7b is connected to the ground, and the output of the A / D converter 7c is connected to the input terminal of the microcomputer 8.

The pan cooling means 9 for cooling the pan 1 comprises a fan motor 9a, a bidirectional three-terminal thyristor 9b, a resistor 9c, a transistor 9d, and a resistor 9e. One terminal of the fan motor 9a is connected to one side of the AC power supply 10, and the other terminal of the fan motor 9a is connected to the T2 terminal of the bidirectional three-terminal thyristor 9b. Further, the T1 terminal of the bidirectional three-terminal thyristor 9b is connected to the other side of the AC power supply 10. One terminal of the resistor 9e is connected to a DC power supply 11 for inputting an AC voltage of the AC power supply 10 and outputting a DC voltage, and the other terminal of the resistor 9e is connected to a base of the transistor 9d and an output terminal of the microcomputer 8. Connected
The emitter of the transistor 9d is connected to the ground. The collector of the transistor 9d is connected to one terminal of the resistor 9c, and the other terminal of the resistor 9c is connected to the gate terminal of the bidirectional three-terminal thyristor 9b.

The microcomputer 8 constituting the control circuit inputs both outputs of the thermistor 6a of the pot temperature detecting means 6 and the thermistor 7a of the lid temperature detecting means 7, and the main heating means 3 (heater 3a) Means 4 (heater 4a), lid heating means 5 (heater 5a), and pan cooling means 9 (fan motor 9a) are output to cool pan 1 and keep the temperature of pan 1 and the temperature of inner lid 2 warm. It is controlled according to the sequence.

The operation of the above configuration will be described with reference to the flowchart of FIG. At S30, the microcomputer 8
Inputs the output of the A / D converter 6c using the temperature of the pan 1 as digital data. Further, the output of the A / D converter 7c is input as digital data using the temperature of the inner lid 2 as digital data. Further, the microcomputer 8 outputs to the base terminal of the transistor 3 d of the main heating means 3, the base terminal of the transistor 4 d of the heat retaining / heating means 4, and the base terminal of the transistor 5 d of the lid heating means 5, and outputs the temperature of the pan 1. And the temperature of the inner lid 2 is controlled in accordance with the rice cooking sequence.

Next, the process proceeds to S31. In S31, the microcomputer 8 determines whether or not the rice cooking process has been completed.
If not, the process returns to S30 to continue the rice cooking process.
When the process is completed, the process proceeds to S32. In S32, the microcomputer 8 uses the temperature of the pan 1 as digital data and
The output of the / D converter 6c is input, and it is determined whether or not the temperature θ of the pan 1 is equal to or higher than the heat retention temperature θ1. Here, the insulation temperature θ1
Is 71.5 ° C. This value may be any value as long as it can keep the rice warm. Immediately after entering the warming process from the rice cooking process, the temperature θ of the pot 1 is higher than the warming temperature θ1, so the process proceeds to S33. In S33, the microcomputer 8 opens the output terminal connected to the base terminal of the transistor 9d, makes the bidirectional three-terminal thyristor 9b conductive, and rotates the fan motor 9a to cool the pot 1 by air.

Next, the process proceeds to S34. In S34, the microcomputer 8 inputs the output of the A / D converter 7c using the temperature of the inner lid 2 as digital data and
Is greater than or equal to φ1. The value of φ1 is the heater 5a
Is set to a value that does not exceed the heat resistant temperature of 113 ° C. If the temperature φ of the inner lid 2 is equal to or higher than φ1 in S34, the process proceeds to S35.

In S35, the microcomputer 8 sets the output terminal connected to the base terminal of the transistor 5d to a low level state, turns off the bidirectional three-terminal thyristor 5b, stops power supply to the heater 5a, and turns off the inner lid 2. Stop heating. If the temperature φ of the inner lid 2 is lower than φ1 in S34, the process proceeds to S36. In S36, the microcomputer 8 sets the output terminal connected to the base terminal of the transistor 5d to the open state, makes the bidirectional three-terminal thyristor 5b conductive, energizes the heater 5a, and heats the inner lid 2. As a result, the dew on the inner lid 2 is evaporated to prevent the dew from being formed.

In S35 and S36, the microcomputer 8
Sets the output terminal connected to the base terminal of the transistor 4d to the low level state, turns off the bidirectional three-terminal thyristor 4b, stops the power supply to the heater 4a, and sets the pan 1
Insulation heating has been stopped. The process returns from S35 and S36 to S32. Entering the warming process from the rice cooking process, the temperature of the pan 1 becomes θ,
The time until the temperature becomes lower than the heat retention temperature θ1 becomes shorter because the fan motor 9a is rotated and the pan 1 is air-cooled in S33, and the time for repeating S35 and S36 from S32 becomes shorter and the power consumption becomes smaller.

In step S32, the heating process is started from the rice cooking process, and the pot 1
When the temperature θ becomes lower than the heat retention temperature θ1, the process proceeds to S37.
In S37, the microcomputer 8 sets the transistor 9
The output terminal connected to the base terminal of d is set to a low level, the bidirectional three-terminal thyristor 9b is turned off, the fan motor 9a is stopped, and the temperature θ of the pan 1 is easily maintained at the heat retaining temperature θ1. . The process proceeds from S37 to S38.
In S38, the microcomputer 8 inputs the output of the A / D converter 6c using the temperature of the pan 1 as digital data and determines whether or not the temperature θ of the pan 1 is equal to or higher than the heat retention temperature θ1.

When the temperature θ of the pot 1 is higher than the heat retaining temperature θ1, the process proceeds to S39. In S39, the microcomputer 8 sets the output terminal connected to the base terminal of the transistor 4d to a low level state, and sets the bidirectional three-terminal thyristor 4b
Is turned off, the power supply to the heater 4a is stopped, and the heating of the pan 1 is stopped.

Further, the microcomputer 8 sets the output terminal connected to the base terminal of the transistor 5d to a low level state, makes the bidirectional three-terminal thyristor 5b non-conductive, stops the power supply to the heater 5a, and turns off the inner lid 2. Stop heating. If the temperature θ of the pot 1 is lower than the heat retaining temperature θ1 in S38, the process proceeds to S40.

In S40, the microcomputer 8 converts the temperature of the inner lid 2 into digital data by using the A / D converter 7 as the digital data.
The output of c is input to determine whether the temperature φ of the inner lid 2 is equal to or higher than φ1. When the temperature φ of the inner lid 2 is lower than φ1 in S40,
Proceed to S41. In S41, the microcomputer 8 opens the output terminal connected to the base terminal of the transistor 4d, makes the bidirectional three-terminal thyristor 4b conductive, energizes the heater 4a, and heats the pot 1.

Further, the microcomputer 8 makes the output terminal connected to the base terminal of the transistor 5d open, makes the bidirectional three-terminal thyristor 5b conductive, energizes the heater 5a, and heats the inner lid 2. .
As a result, the dew on the inner lid 2 is evaporated to prevent the dew from being formed.

If the temperature φ of the inner lid 2 is not less than φ1 in S40,
Proceed to S42. In S42, the microcomputer 8 opens the output terminal connected to the base terminal of the transistor 4d, makes the bidirectional three-terminal thyristor 4b conductive, and energizes the heater 4a to heat the pot 1.
Further, the microcomputer 8 sets the output terminal connected to the base terminal of the transistor 5d to a low level state, makes the bidirectional three-terminal thyristor 5b non-conductive, stops energizing the heater 5a, and stops heating the inner lid 2. Stop.

Returning from S39, S41, S42 to S37, the above operation is repeated. In this manner, the rice cooker enters the heat retaining step and cools the pot 1 until the temperature of the pan 1 becomes lower than the heat retaining temperature.
In other words, the time during which the temperature is lower than the heat retention temperature θ1 is shortened, the time for heating the inner lid is shortened, and the heat can be retained with little power consumption without dew on the inner lid.

[0037]

As described above, the control circuit of the rice cooker according to the present invention, when entering the warming step from the rice cooking step, raises the temperature of the pan.
Cool the pan with the pan cooling means until it falls below the heat retention temperature, shorten the time when the temperature of the pan is lower than the heat retention temperature,
There is an effect that the time for heating the inner lid is shortened, and it is possible to keep the temperature of the inner lid with little power consumption and no dew on the inner lid.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control circuit of a rice cooker according to one embodiment of the present invention.

FIG. 2 is a specific circuit diagram of the control circuit of FIG.

FIG. 3 is a flowchart showing the operation of FIG. 2;

FIG. 4 is a block diagram of a control circuit of a conventional rice cooker.

FIG. 5 is a flowchart showing the operation of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pot, 2 ... Inner lid, 3 ... Main heating means, 4 ... Heat keeping heating means, 5 ... Lid heating means, 6 ... Pot temperature detection means,
7: lid temperature detecting means, 8: control means (microcomputer), 9: pan cooling means.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Makoto Katakasu 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. In-company (56) References JP-A-60-227719 (JP, A) JP-A-3-261415 (JP, A) JP-A-3-112515 (JP, A) JP-A-2-116321 (JP, A) ) Japanese Utility Model 57-132630 (JP, U) Japanese Utility Model 41-10849 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) A47J 27/00

Claims (1)

(57) [Claims] 1. A pot for putting rice for cooking rice and water, an inner lid located above an opening of the pot, a main heating means for heating the pot during rice cooking, and a heat insulator for heating the pot during heat insulation. Heating means, lid heating means for heating the inner lid, pan temperature detecting means for detecting the temperature of the pan, lid temperature detecting means for detecting the temperature of the inner lid, and pan cooling means for cooling the pan And the temperature of the pot is kept warm when entering the warming process from the rice cooking process.
Output to the pan cooling means until the temperature drops below , cool the pan, input both outputs of the pan temperature detection means and the lid temperature detection means, the main heating means, the heat insulation heating means, A control means for outputting to the lid heating means and controlling the temperature of the pan and the temperature of the inner lid in accordance with a heat retention sequence.