JPH0515440A - Control circuit for rice cooker - Google Patents

Abstract

PURPOSE:To provide a control circuit for a jar type rice cooker which can cook rice with a delicious taste even in a reserved cooking mode by solving such a problem that rice is immersed in water for a long waiting time in a reserved cooking mode, in comparison with a usual rice cooking mode, since the rice is not cooked until the time of initiation of cooking in order to cease the cooking of rice at a reserved time in the case of cooling the rice with an energization rate the same as that of the usual cooking, and accordingly, the rice absorbs water, causing components such as starch to deposit on the bottom so that the rice is seriously burnt. CONSTITUTION:A determining means 34 determines an energization rate Pg/16 for a relay 23, an adjusting means 35 subtracts 1 from PG determined by the determining means 34 only when the reserved time is more than 2 hours after a time of initiation of a reserved cooking mode. A control means 34 controls drive circuits 25, 26 in accordance with Pg, and accordingly, the control circuit can cook the rice with a delicious taste while the rice is hardly burnt even in the reserved cooking mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker control circuit having a reservation function.

[0002]

2. Description of the Related Art In recent years, a jar rice cooker having a reserved rice cooking function, such as cooking rice so that it is finished at a certain set time or finishing it after a certain set time, has become widespread.

A control circuit of a conventional jar rice cooker will be described below. FIG. 2 shows the configuration of a control circuit of a conventional jar rice cooker. In FIG. 2, 1 is an AC power supply,
2 is a power supply circuit, which supplies a DC voltage to the circuit. Reference numeral 3 is a bottom heater, and 4 is a body heater, which are energized by a relay 5 and a bidirectional thyristor 6, respectively. The relay 5 is driven by a relay drive circuit 7, and the bidirectional thyristor 6 is driven by a bidirectional thyristor drive circuit 8. A temperature detection circuit 9 detects the temperature of the food. Reference numeral 10 denotes a liquid crystal display element (hereinafter referred to as LCD) which is a display means, 10a
Is the current time, 10b is the end time of cooking rice (hereafter, the reservation time)
Is shown. 11 is a reservation setting start key (hereinafter, reservation key), 12 is an hour key for setting an hour digit of a reservation time, 13 is a minute key for setting a minute digit of a reservation time, 14 is a rice cooking start key (hereinafter, rice cooking key) , 15 is a measuring means for measuring the temperature rise time from the detected value of the temperature detecting circuit 9, 16 is a determining means for determining the energization ratio of the relay 5, the bidirectional thyristor 6, and 17 is based on the determined energization ratio. It is assumed that the control means for controlling the drive circuits 7 and 8, the measuring means 15, the determining means 16 and the control means 17 are built in the microcomputer 18.

The operation of the control circuit of the jar rice cooker configured as described above will be described below. Similarly at the time of reserved rice cooking or normal rice cooking, the measuring means 15 measures the time according to the value of the temperature detection circuit 9, and the determining means 16 determines the relay 5 and the bidirectional thyristor 6 according to the time.
Determine the energization ratio of. The control means 17 controls the drive circuits 7 and 8 based on the energization ratio.

[0005]

However, in the above-mentioned conventional structure, the same energization ratio is generated during the reserved rice cooking and the normal rice cooking. If the rice is cooked at the same energization ratio as the regular rice cooked during the reserved rice cooking, there is a time waiting for the rice to start cooking at the reserved time during the reserved rice cooking. Since it is soaked in water for a long time, the cooked food absorbs water correspondingly, and components such as starch settle on the bottom, which causes a problem of severe burns.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a control circuit of a jar rice cooker which can cook a deliciously burnt food even when reserved rice is cooked.

[0007]

In order to achieve this object, the control circuit of the rice cooker according to the present invention comprises a setting means for setting a rice cooking end time or a time until the rice cooking is finished, and a heating means for heating an object to be cooked. A switching element for energizing the heating means, a drive circuit for driving the switching element, a temperature detection circuit for detecting the temperature of the food to be cooked, and a temperature rise of a detection value of the temperature detection circuit. Determining means for determining the energization ratio when the heating means is boiling, and adjusting means for reducing the energization ratio determined by the deciding means by a certain value only when the scheduled rice cooking end is a certain time or more after the reserved rice cooking start, The control means controls the drive circuit based on the energization ratio thus determined.

[0008]

According to the present invention having such a configuration, in the case of reserved rice cooking, when the scheduled rice cooking end is after a certain time or more after the reserved rice cooking start, a certain value is subtracted from the energization ratio determined by the determining means. The heating means is controlled by the energization ratio. That is, when the cooked food is submerged for a certain period of time or more, it tends to burn, so that it is possible to cook with a slightly weaker heating power than ordinary rice to suppress burns and cook more deliciously.

[0009]

An embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 19 is an AC power supply and 20 is a power supply circuit, which supplies a DC voltage to the circuit. Reference numeral 21 is a bottom heater, and 22 is a body heater, which are energized by a relay 23 and a bidirectional thyristor 24, respectively. Relay 23
Is driven by a relay drive circuit 25, and the bidirectional thyristor 24 is driven by a bidirectional thyristor drive circuit 26. Reference numeral 27 is a temperature detection circuit, which detects the temperature of the food. 28 is an LCD as a display means, 28a is the current time, and 28b is the reserved time. 29, 30, 31
Is a reservation key, an hour key, and a minute key which are reservation time setting means. The hour key 30 sets the hour digit of the reservation time, and the minute key 3
1 sets the minute digit of the reserved time. 32 is a rice cooking key, 33
Is a measuring means for measuring the temperature rise time from the detected value of the temperature detection circuit 27, and 34 is the energization ratio Pg / 16 of the relay 23.
Determining means for determining (Pg second relay 23 is turned on for 16 seconds in a 16-second cycle), and when 35 is the reserved rice, the determining time is determined by the determining means 34 only when the reserved time is two hours or more after the reserved rice starting time. The adjustment means for subtracting 1 from Pg, 36 is the drive circuit 2 based on the determined energization ratio.
5, the control means for controlling 5, 26, the measuring means 33, the determining means 34, the adjusting means 35, and the control means 36 are the microcomputer 3
It is assumed to be built in 7.

The operation of the control circuit of the jar rice cooker thus configured will be described. First, the reservation key 29 is pressed to enter the reservation time setting mode. LCD2
8, the reserved time 28b is set using the hour key 30 and the minute key 31. Then, the rice cooking key 32 is pressed to start the reserved rice cooking.

When the waiting time ends and the rice cooking start time comes, rice cooking is started and the bottom heater 21 and the body heater 22 heat the food. Temperature detection circuit 27 and measuring means 3
3 is used to determine the time T until the temperature of the cooked food changes from θ3 to θ4. Then, the determining means 34 determines the energization ratio Pg / 16 based on the time T. The adjusting means subtracts 1 from Pg when the reserved time is two hours or more after the reserved rice start time during the reserved rice cooking. Then, the control means 36 controls the drive circuits 25 and 26 based on this energization ratio.

As described above, in the case of reserved rice cooking, the cooked food is apt to burn when the cooked food is submerged for a certain period of time or more. Therefore, the burned food can be suppressed by cooking with a slightly weaker heating power than the normal cooked rice. It is a thing.

Although the heater is used as the heating means in the present embodiment, an induction heating coil or a gas combustion instrument may be used, or a heating system using a combination of a heater and an induction heating coil may be used.

[0015]

As described above, according to the present invention, after the determination of the energization ratio, when the rice cooking end reservation is more than a certain time after the reservation rice cooking start, a certain value is subtracted from the previously determined energization ratio. The heating means is controlled by the energization ratio. In other words, the cooked food is soaked in water for a certain time or longer, the cooked food absorbs water well, and the starch is also likely to settle to the bottom, which makes it easier to burn. As a result, the burner can be suppressed even at the time of reserved rice cooking, and the control circuit of the jar rice cooker that can cook more deliciously can be obtained.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a control circuit of a jar rice cooker according to a conventional example of the present invention.

[Explanation of symbols]

 21 Bottom heater 22 Body heater 23 Relay 24 Bidirectional thyristor 25 Relay drive circuit 26 Bidirectional thyristor drive circuit 27 Temperature detection circuit 28 LCD (display means) 29 Reservation key (setting means) 30 o'clock key (setting means) 31 minutes Key (setting means) 33 Measuring means 34 Determining means 35 Adjusting means 36 Control means 37 Microcomputer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yumiko Hirata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A setting means for setting a rice cooking end time or a time until rice cooking is completed, a heating means for heating an object to be cooked, and a switching element for energizing the heating means.
A drive circuit that drives the switching element, a temperature detection circuit that detects the temperature of the food to be cooked, and a determination unit that determines the energization ratio of the heating unit when the heating unit is boiling based on the temperature increase of the detection value of the temperature detection circuit. Adjusting means for reducing the energization ratio determined by the deciding means by a certain value only when the scheduled rice cooking end time is longer than the reserved rice cooking start time, and the drive circuit based on the thus determined energizing ratio. The control circuit of the rice cooker comprising the control means for controlling the rice cooker.