JPH0542034A - Rice cooker - Google Patents

Abstract

PURPOSE:To provide a small rice cooker capable of monitoring a vessel at all times, by a method wherein a vessel-detecting means for electrically detecting the vessel is provided instead of a mechanical vessel-detecting means. CONSTITUTION:A heating means 5 is allowed to operate at intervals of a definite time, a vessel-detecting means 2 is allowed to operate at each of every times when the heating means starts to operate, and after the vessel-detecting means 2 is allowed to operate, an information means 8 is allowed to operate. In addition, a time-transferring circuit 6c is provided and the operation time of the heating means 5 is varied corresponding to a level outputted from a temperature-detecting means 4. Furthermore, just after a menu is set, it is detected by the vessel-detecting means 2 whether a vessel 3 exists or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker which heats and heats a pot by heating means such as induction heating.

[0002]

2. Description of the Related Art In recent years, rice cookers have been commercialized that use the principle of electromagnetic induction heating as a heating source instead of a sheathed heater.

A conventional rice cooker will be described below. FIG. 4 shows a cross-sectional view of the body of a conventional rice cooker.

In FIG. 4, reference numeral 10 is a rice cooker main body, and an inverter circuit 5 for supplying high-frequency power to an operating section 7 at the upper part of the main body 10 and a heating coil 5f at the lower part, and an inverter circuit 5
A cooling fan 17 for cooling the motor and a control circuit 6 for controlling the inverter circuit 5 are provided. Reference numeral 3 denotes a pot for putting food to be cooked therein, which is installed in the pot storage portion 11 of the main body 1 and the upper portion of the pot 3 is covered with an upper lid 12. Reference numeral 2a denotes a pan detection device that mechanically moves up and down at the center of the bottom of the pan 3 to detect the presence or absence of the pan 3.
The heating coil 5f is placed on the coil support base 9, and a ferrite core 16 is attached below the coil support base 9.

Regarding the rice cooker configured as described above,
The operation will be described below. First, the pan detector 2a
When the pan 3 is not present, the pan detection device 2a does not operate, so the keys on the operation unit 7 cannot be operated, and the rice cooker does not operate at all. In addition, if the pan 3 is removed from the rice cooker body 10 during rice cooking or heat retention, after a certain period of time, for example, about 5
After a second, the pan detection device 2a does not operate, the menu setting so far is canceled, and the key operation of the operation unit 7 cannot be performed until the pan 3 is returned to the main body 10. In addition, during the timer-reserved rice cooking, the pot 3
When is removed from the rice cooker main body 10, the menu setting of the timer is not canceled, but the operation unit 7 displays a no-pot display to inform the user that the pan 3 is not present. Therefore, in any menu setting, if there is no pan 3 in the rice cooker, the operation section 7 displays a no pan.

[0006]

However, in the above conventional configuration, the pan detecting device 2a which mechanically moves up and down to detect the presence or absence of the pan 3 is indispensable for detecting the pan 3. If this pan detecting device 2a is abolished and the detecting means of the pan 3 is changed to a method of detecting the heating state of the pan 3 and electrically detecting it, the pan 3
It is difficult to detect the presence or absence of the pot 3 unless the pan is heated. In particular, since the pan 3 is not heated during warming immediately after the rice is cooked, during timer reserved rice cooking, etc., in the conventional rice cooking program sequence, when the pan 3 is removed from the main body 10, the pan 3 is cooked.
There is a problem that it is not possible to electrically determine the presence or absence of.

The present invention solves the above-mentioned conventional problems, in which the presence or absence of a pot is determined by a pot detecting means for electrically detecting the presence or absence of a pot by heating the pot with a constant power. Then, while the rice cooker is operating, the heating means is operated at regular time intervals, for example, every minute, and the presence or absence of the pan is detected by the pan detection means each time. Therefore, even if the pan detection device that mechanically detects the presence or absence of the pan is abolished, it is the first to provide a rice cooker that can always detect the presence or absence of the pan even during the heat retention immediately after the rice is cooked, the timer reserved rice is cooked, etc. To aim. Also, it is possible to provide a rice cooker that reduces the influence on the rice and the heat retention performance of the rice even if the heating means performs the heating operation at regular time intervals during the heat retention immediately after the rice is cooked or during the timer reserved rice. The second purpose. A third object is to provide a rice cooker that can detect the presence or absence of a pot immediately after setting the menu of the operation unit.

[0008]

In order to achieve the first object, the first means of the present invention is a pan for cooking rice, a heating means for heating the pan, and a control section for controlling the heating means. , Temperature detecting means for detecting the temperature of the pan, pan detecting means for detecting the presence or absence of the pan by keeping the pan in a constant heating state, notification means for notifying whether the pan is proper or not, rice cooking, heat retention, timer reservation The control section operates the heating means at regular time intervals and operates the pan detecting means for a constant time immediately after the operation of the heating means, and the notification means after the operation of the pan detecting means. Has a configuration that operates.

In order to achieve the above-mentioned second object, the second means of the present invention, in addition to the above-mentioned first means, is provided with a time switching circuit so that the temperature detected by the temperature detecting means is equal to or higher than a predetermined temperature. At times, the time switching circuit has a configuration in which the operating time interval of the heating means is made longer than when the temperature is lower than a predetermined temperature.

Further, in order to achieve the above-mentioned third object, in the third means of the present invention, in addition to the first means, the control section operates the heating means for a certain period of time immediately after setting the menu of the operation section. Have a configuration.

[0011]

With this configuration, in the rice cooker of the present invention, in the first means, when the rice cooking menu is set by the operation unit, the heating means operates after a certain period of time other than the timer-reserved rice cooking, and the pan is induction-heated. To do. At this time, as soon as the heating means operates, the pot detecting means makes the pot a constant power and detects the presence or absence of the pot. In the rice cooking process, the heating means adjusts the electric power in accordance with the temperature detected by the temperature detecting means, completes the rice cooking work through each of the steps of pre-cooking, up-cooking and muramura, and then automatically shifts to heat retention. Then, keep the rice warm at about 70 ℃.

Even during rice cooking, the pot detecting means always detects the presence or absence of the pot by heating the pot with a constant power immediately after the heating means starts its operation. Regardless of the temperature, the heating means is always operated at fixed time intervals, the pan detection means heats the pan with a constant power to detect the presence or absence of the pan, and when it judges that there is no pan, it sends a signal to the notification means. , No pan can be displayed on the operation unit to inform the user of no pan. If timer-scheduled rice is set on the operation unit, the control unit operates the heating unit at fixed time intervals and heats the pan with a constant power even during the waiting time until rice cooking starts. The presence or absence of a pan is constantly detected, and if it is determined that there is no pan, as in the case of keeping warm, a signal is sent to the notification means and the pan is displayed on the operation unit to inform the user of the absence of a pan. ..

Next, according to the second means, during heat retention,
When the pot is above a predetermined temperature, such as during the period when the temperature of the pot drops to 70 ° C after the completion of rice cooking, the constant time interval for heating by the heating means is compared to when the pot is below the predetermined temperature. You can make it longer and keep the taste of the rice.

In the third means, at the same time when the user sets the menu of the operation section, the heating means is operated immediately and the pot detecting means heats the pot with a constant power to detect the presence or absence of the pot. When judged, send a signal to the notification means,
No pan can be displayed on the operation unit to inform the user of no pan.

[0015]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an electric circuit configuration of a jar rice cooker using induction heating to show a first embodiment of the present invention for achieving the first object. Reference numeral 1 is a commercial power source and heating means. Is connected to the inverter circuit 5. Inverter circuit 5
Is a rectifier 5a connected to the commercial power source 1 and a rectifier 5a
, A choke coil 5c connected in series, a smoothing capacitor 5d, a resonance capacitor 5e connected to the smoothing capacitor 5d, an anti-parallel connected diode 5h and a switching element 5g. There is. Capacitor 5b and choke coil 5c
And form a filter circuit. The heating coil 5f for inductively heating the pot 3 is connected in parallel with the resonance capacitor 5e and constitutes a resonance circuit. The control unit 6 adjusts the ON-OFF operation of the switching element 5g, and controls the heating amount for the heating coil 5f to induction-heat the pot 3. Reference numeral 2 denotes a pot detecting means for heating the pot 3 with a constant power to detect the presence or absence of the pot 3, and detects the presence or absence of the pot 3 by the magnitude of the input current of the inverter circuit 5. Inverter circuit 5
The input current is detected by, for example, a current transformer or the like. At the center of the bottom of the pot 3, temperature detecting means 4 for detecting the temperature of the pot 3 is provided, which is, for example, a thermistor, and the output of the temperature detecting means 4 is sent to the control section 6. There is. The control unit 6 receives a signal from the rice cooking setting key or the heat retention setting key (both not shown) of the operation unit 7, and the heating time set by the timer circuit 6a according to the temperature of the pan 3 detected by the temperature detecting means 4. Only drive circuit 6
b is driven. The operation unit 7 is composed of setting keys for menu selection, rice cooking, timer setting, heat retention / cancellation, etc., a liquid crystal display unit (hereinafter referred to as LCD), and a display unit such as an LED. Further, the control unit 6 outputs a signal to the notification unit 8 according to the level of the output signal of the pan detection unit 2.

FIG. 2 is an electric circuit configuration diagram of a jar rice cooker using induction heating showing a second embodiment of the present invention for realizing the second object. The first object of FIG. In addition to the electric circuit configuration of the jar rice cooker using induction heating for showing the first embodiment of the present invention to realize the above, a time switching circuit 6c is provided in the control unit 6 to output the temperature detecting means 4. According to the configuration, the timer time of the timer circuit 6a is switched.

FIG. 3 is a cross-sectional view of a jar rice cooker body using induction heating showing a first embodiment of the present invention for achieving the first object, and a pot 3 for putting rice and water inside. A storage section 11 for storing the above is provided, and the upper portion of the main body 10 is openably and closably covered by the upper lid 12 so that the pan 3 can be taken out by opening and closing the upper lid 12. Reference numeral 5f is a heating coil for inductively heating the pot 3, which is placed on the support base 9 and below the support base 9 is a ferrite core 1 for absorbing leakage magnetic flux.
A plurality of 6 are provided radially. Although not shown in FIG. 3, the main body 10 has a built-in battery that backs up the power source of the microcomputer of the control unit 6 and the like, and stores the previous setting state even if a power failure or a power outlet is unplugged. When the electricity is restored or the power outlet is inserted, it is set to the previous state.

In the above structure, when the rice cooking mode is set by the rice cooking setting key of the operation unit 7, the control unit 6 turns the switching element 5g on and off to supply the high frequency current to the heating coil 5f. An eddy current is generated at the bottom of the pot 3 due to the magnetic field generated by the high-frequency current, and the pot 3 itself generates heat to cook rice. Then, when rice cooking is completed, the setting automatically switches to heat retention mode,
The control unit 6 controls the heating means 5 to keep the rice warm so that the pot 3 is at a temperature of ℃. Further, even if the heat retention setting key is set, the control unit 6 controls the heating means 5 to keep the rice warm so that the pot 3 is brought to a temperature of about 70 ° C. as described above.
The normally set mode is designed to maintain the current set mode in the event of a power failure with a backup battery.

Here, in particular, when the timer reservation rice cooking mode is set by the timer setting key or immediately after the rice cooking is completed and the rice is automatically switched to the heat retention, the timer circuit 6a in the control unit 6 sets a predetermined time interval. For example, the drive circuit 6b is driven for about 1 second every 10 minutes. When the drive circuit 6b drives, the switching element 5g operates and the inverter circuit 5 heats the pan 3. The pot detecting means 2 outputs a signal to the control unit 6 so as to heat the pot 3 with a constant power, for example, a low power such as 500 W which is about 40% of the rated power, and determines from the current amount of the current transformer. It detects whether or not the pot 3 is present and whether or not the pot 3 is proper, and outputs a signal to the control unit 6. The pan detecting means 2 detects the pan 3 by heating the pan 3 with a low power of 500 W so that the inverter circuit 5 does not operate without the pan or the aluminum pan with the rated power so as to prevent the switching element 5g from being destroyed. .. At this time, for example, the pan 3 is the main body 1
When it is taken out from inside 0, the output signal level of the pan detection means 2 becomes small, the control unit 6 judges that the pan 3 does not exist in the main body 10, sends a signal to the notification means 8, and the notification means 8
Tells that there is no pan on the LCD. Therefore, even when the timer reservation rice cooking mode is set by the timer setting key, or immediately after the rice cooking is completed and the rice is automatically switched to the heat retention, even if the pan 3 is taken out from the main body 10, the same interval is maintained. Since the pot 3 is heated every time, the user can be notified of the absence of the pot. Further, in FIG. 1, immediately after the user sets the setting key of the operation unit 7 in the timer circuit 6a in the control unit 6 to realize the third object,
Since a signal is sent to the drive circuit 6b so that the inverter circuit 5 operates, the user may accidentally operate the main body 1
Even if the timer reserved rice is set by the operation unit 7 without setting the pan 3 to 0, the control unit 6 receives the signal from the pan detection unit 2 and sends a signal to the notification unit 8 by the operation of the timer circuit 6a. By sending and notifying the user that there is no pot, the user can know that the main body 10 does not have the pot 3.

Next, FIG. 2 is an electric circuit configuration diagram of a jar rice cooker using induction heating showing a second embodiment of the present invention for achieving the second object. In addition to the electric circuit configuration of the jar rice cooker using induction heating showing the first embodiment of the present invention for achieving the above object, a time switching circuit 6c is provided, and the operation time interval of the timer circuit 6a is set. The configuration is switched according to the output of the temperature detecting means 4.

In the above structure, when the temperature of the pot 3 is high, for example, immediately after the rice is cooked when the temperature is kept warm, for example, if the pot 3 is at 75 ° C. or higher, the timer circuit 6a operates the drive circuit 6b. Time interval, for example 10 minutes to 3
It switches to 0 minutes. With such a configuration, even if the heating means 5 is operated at a constant time interval in order to detect the presence or absence of the pan 3, the presence or absence of the pan 3 will not be affected to the extent that it does not affect the taste of cooked rice. Can always be detected.

[0023]

As is clear from the description of the above embodiment,
According to the present invention, an excellent rice cooker having the following effects can be realized.

(1) When the presence or absence of a pan is detected, the pan is detected by heating with a certain low power, so that the switching element can be prevented from being destroyed even if there is no pan or an aluminum pan is inserted.

(2) Since the presence / absence of a pot is always electrically detected at regular time intervals, the mechanical pot detector can be eliminated, the cost can be reduced, and the space of the main body can be saved.

(3) Even if the mechanical pan detector is abolished,
Since the pan is electrically detected by always heating the pan with the heating means, the user is informed of the absence of the pan even if the pan is removed from the main body even when the rice is kept warm or the timer reserved rice is cooked.

(4) The mechanical pot detecting device is abolished and the heating means is operated at fixed time intervals to detect the presence or absence of the pot. However, when the pot is above a predetermined temperature during heat retention. Since the constant time interval for operating the heating means is set longer than when the pot is at a predetermined temperature or lower, the temperature can be kept warm without affecting the taste of the rice.

(5) Even if the mechanical pan detector is abolished,
Immediately immediately after the menu of the operation unit is set, the pan is electrically detected by heating the pan by the heating means and the user is notified that there is no pan, so the timer reserved rice cooked without the pan. It is possible to prevent setting.

[Brief description of drawings]

FIG. 1 is an electric circuit configuration diagram of a jar rice cooker according to a first embodiment of the present invention.

FIG. 2 is an electric circuit configuration diagram of a jar rice cooker according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a main body of a jar rice cooker according to an embodiment of the present invention.

FIG. 4 is a sectional view of the body of a conventional jar rice cooker.

[Explanation of symbols]

 2 Pan detecting means 3 Pan 4 Temperature detecting means 5 Heating means 6 Control section 7 Operating section 8 Notification means 9 Time switching circuit

Claims (3)

[Claims] 1. A pot for cooking rice, and heating means for heating the pot,
A control unit for controlling the heating means, a temperature detecting means for detecting the temperature of the pan, a pan detecting means for detecting whether or not the pan is in a constant heating state, and a notifying means for notifying whether the pan is proper or not. And an operation unit for setting menus such as rice cooking, heat retention, timer reservation, etc., and the control unit operates the heating means at fixed time intervals and operates the pan detection means for a fixed time immediately after the operation of the heating means. , A rice cooker in which the notification means operates after the operation of the pan detection means. 2. A time switching circuit is provided, and when the temperature detected by the temperature detecting means is equal to or higher than a predetermined temperature, the time switching circuit makes the operating time interval of the heating means longer than when the temperature is lower than the predetermined temperature. The rice cooker according to claim 1. 3. The rice cooker according to claim 1, wherein the control unit operates the heating means for a certain period of time immediately after setting the menu of the operation unit.