JPH0810158A - Rice cooker - Google Patents

Abstract

PURPOSE:To prevent a trouble of making rice unable to eat even when a fault of a pot sensor or a lid sensor is detected. CONSTITUTION:A pot sensor fault detection means 66 detects a fault of disconnection of a pot sensor 9 immediately after the starting of a cooking with rice immersed in water. A lid sensor fault detection means 67 detects a fault of disconnection of a lid sensor 29 immediately after the starting of a steam heating. When the fault of the pot sensor 9 or the lid sensor 29 is detected, the heating with induction coils 6 and 7 is stopped. As a result, even when a rice cooking operation is stopped in the half way because of the fault of the pot sensor 9 or the lid sensor 29, the condition of the initial water-immersed cooking or after cooking up is kept in the pot. In any case, half-cooked rice in the pot 4 can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker in which the pot temperature detecting means and the lid temperature detecting means improve the heating operation in the case of a failure due to a disconnection or the like.

[0002]

2. Description of the Related Art Conventionally, in this type of rice cooker, a function of detecting a disconnection failure of a thermistor, which is a temperature detecting means for detecting the temperature of a pot or a lid, is disclosed in, for example, Japanese Patent Publication No. 5-46203. Can be applied. That is, if the temperature of the thermistor is equal to or lower than a predetermined temperature (for example, -20 ° C.) after the power of the pan is heated for a predetermined time and the output of the thermistor is changed by energizing the pot heating means. It was decided that the trouble was caused by a disconnection, and the power to the pot heating means was stopped. In general,
Since the resistance value of the thermistor at the time of disconnection is infinite as well as when detecting low temperature, if disconnection detection is performed without heating the pot heating means, when the outside air temperature is extremely low,
There is a risk that the wire breakage may be erroneously detected, but if the wire breakage is detected after the pot heating means is energized for a predetermined time (for example, 1 minute), the temperature detected by the thermistor is -20 ° C during normal operation. On the other hand, in the case of a disconnection failure, the temperature detected by the thermistor remains below −20 ° C., so that even if the outside air temperature is low, the disconnection can be reliably detected without error.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The disconnection detection in the above-mentioned prior art is applied to a rice cooker equipped with a lid temperature detecting means for detecting a temperature of a lid in addition to a pot temperature detecting means for detecting a temperature of a pot. In this case, it takes longer than the pot to ensure that the temperature of the lid rises reliably. For example, after the pot reaches near the boiling state or after the lid heater heats the lid, the lid temperature detecting means It is necessary to start the wire break detection. However, in this case, if the lid temperature detecting means has a disconnection failure, the power to the pan heating means will be forcibly stopped during the rice cooking operation, and the rice contained in the pan will be cooked raw. There is a problem that it becomes inedible.

Therefore, in view of the above circumstances, the present invention can prevent a rice cooker from becoming inedible even when a failure of the pan temperature detecting means or the lid temperature detecting means is detected during the rice cooking operation. The purpose is to provide.

[0005]

The rice cooker of the present invention covers a pan, a pan heating means for heating the pan, a pan temperature detecting means for detecting the temperature of the pan, and an upper opening portion of the pan. The lid, the lid temperature detecting means for detecting the temperature of the lower surface of the lid, and the heating control from the start of rice cooking to the uneven heating based on the temperatures detected by the pot temperature detecting means and the lid temperature detecting means. The rice cooking control means for the rice cooker and the failure detection of the pot temperature detecting means after starting the rice cooking by the rice cooking control means are started, and when the temperature detected by the pot temperature detecting means is below a predetermined temperature, the pot heating means First failure detection means for stopping heating and failure detection of the lid temperature detection means after the start of the uneven heating by the rice cooking control means are started, and the detected temperature of the lid temperature detection means is equal to or lower than a predetermined temperature. The heating of the pan heating means It is obtained by a second failure detecting means for stopping.

[0006]

With the above structure, the failure of the pan temperature detecting means is detected immediately after the start of rice cooking when the temperature of the pan has not risen so much by the first failure detecting means. Even if you stop, you can re-cook rice by another means without any problem. Further, since the failure detection of the lid temperature detection means is performed after the spotty heating is started by the second failure detection means, even if the heating of the entire pan heating means is stopped at this point, the inside of the pan is already cooked. The raising has been completed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, FIG. 1 showing an overall cross-sectional view of the rice cooker.
In, 1 is a main body with an open top, which is
It is composed of an inner frame 2 which is a pot housing portion and an outer frame 3 made of plastic which is provided so as to surround the outer side of the inner frame 2. Reference numeral 4 denotes a pot that is a container that mainly contains an aluminum material and that stores the food to be cooked. The pot 4 is supported above the inner frame 2 in a suspended state when the inner frame 2 is accommodated. A heating layer 5 made of a magnetic metal material for heating the pot 4 is provided at the bottom and the lower portion of the side surface of the pot 4.

Reference numerals 6 and 7 denote induction coils for induction heating of the heat generating layer 5 provided at the bottom of the outer surface and the lower portion of the side surface of the inner frame 2 as a pot heating means for heating the pot 4. Are arranged at a predetermined distance from the heat generating layer 5. Reference numeral 8 denotes a coil cover that is attached and fixed so as to cover the outside of the induction coils 6 and 7, and prevents leakage magnetic flux from the induction coils 6 and 7. Reference numeral 9 denotes a pan sensor serving as a pan temperature detecting means, which is provided in contact with the bottom surface of the pan 4. The pan sensor 9 is provided with a negative characteristic thermistor (not shown) for detecting the outer surface temperature of the pan 4, and is provided so as to be retractable into an opening 10 formed in the central bottom portion of the inner frame 4. Reference numeral 11 is a control board provided in the lower part of the main body 1, and for example, an inverter circuit for supplying a predetermined high frequency current to the induction coils 6 and 7 is built therein.
An intake port 12 and an exhaust port 13 are provided at the bottom and side parts of the outer frame 3, respectively, and a cooling fan 14 and a motor 15 that constitute a blower are provided inside the device body 1 so as to face the intake port 12. By introducing the outside air into the main body 1 by rotating the cooling fan 14, the induction coils 6, 7 and the control board 11
I am trying to cool such things.

Reference numeral 21 is a lid which covers the upper opening of the pot 4 so as to be openable and closable. The lid body 21 is attached, for example, with an outer lid 22 made of polypropylene resin, an outer lid cover 23 provided along the lower outer periphery of the outer lid 22, and a space below the outer lid 22 to form a space. Heat sink made of aluminum material
24, and an inner lid 26 that closes the upper opening of the pan 4 via an inner lid retainer 25 is detachably attached to the lower portion of the heat dissipation plate 24. 27 is an outer lid cover 23 and a heat sink 24
It is an annular lid packing sandwiched between the
When closed, the lower end of the lid packing 27 comes into close contact with the upper flange portion of the pan 4. A lid heater 28 such as a cord heater is provided on the upper surface of the radiator plate 24 forming the lower surface of the lid as a lid heating means for heating the radiator plate 24 during rice cooking and heat retention, and the temperature of the radiator plate 24 is controlled. As a lid temperature detecting means for detecting, a lid sensor 29 including a negative characteristic thermistor is provided. The lid heater 28 constitutes a parallel circuit with a body heater 30 mainly composed of a code heater provided on the upper outer surface of the inner frame 2 for keeping the inner frame 2 warm. Incidentally, 31 is a steam port for discharging the steam generated from the pan 4 to the outside.

Next, the circuit configuration of the rice cooker will be described with reference to FIG. 2. Reference numeral 41 is a microcomputer mounted on the control board 11, which is, as is well known, a control device 42 constituting a microprocessor and an arithmetic operation. In addition to the device 43, a timer device 44 and a storage device including a ROM and a RAM.
It has 45. An input device 46 composed of an A / D converter is connected to the input side of the microcomputer 41, and the pan sensor 9 and the lid sensor described above are connected via this input device 46.
Along with 29, an operation switch 47, which is an operation means for starting rice cooking and heat retention, and a pan detection sensor 48 for detecting the presence or absence of the pan 4 are connected. On the other hand, the output device 49 is connected to the output side of the microcomputer 41.
A heater driving means 51 having an induction heating means 50 for electromagnetically heating the pot 4 and a switch means such as a triac for controlling the on / off of the body heater 30 and the lid heater 28 at the same time.
And motor drive means 52 for driving the cooling motor 15 are connected. In addition to these, the output device 49 includes a display drive means 54 for controlling display on an LCD / LED display means 53 including an LCD which is a liquid crystal display for displaying time and the like, and an LED for displaying an operating state and the like. In addition to being connected, the buzzer driving means 56 for controlling the ringing of the buzzer 55 for notifying the end of the timer rice cooking is also connected. The microcomputer 41 operates the operation signal of the operation switch 47, the temperature data from the pan sensor 9 and the lid sensor 29, the pan detection signal by the lower limit detection of the input current of the inverter circuit built in the control board 11, and the timer device 44. Depending on time information from
Induction heating means 50, lid heater 28, and body heater 30, L according to a control sequence preset in storage device 45.
It controls the CD / LED display means 53 and the buzzer 55. In addition,
Reference numeral 57 is a power failure backup means that is connected to the output device 49 and backs up the content stored in the storage means 45 of the microcomputer 41 at the time of power failure via the microcomputer drive means 58. In this embodiment, the maximum output of the induction coils 6 and 7 is 1200 W, and the maximum output of the lid heater 28 and the body heater 30 is about 50 W.

A high frequency current is supplied to the induction heating means 50 on the basis of an output signal from the microcomputer 41, and a high frequency current is controlled while varying the high frequency current value to control the interruption / disconnection of the induction coils 6 and 7. A current adjusting means 59 is provided. When a predetermined high frequency current is supplied to the induction coils 6 and 7 from the high frequency current adjusting means 59, an alternating magnetic field is generated in the induction coils 6 and 7, and vortices are generated in the heating layers 5 facing the induction coils 6 and 7, respectively. Electric current is generated,
By converting this eddy current into Joule heat, the heating layer 5
Is heated and the pot 4 is heated.

FIG. 3 is a block diagram showing a processing procedure of a control sequence stored in the storage device 45 of the microcomputer 41. In the figure, reference numeral 61 indicates the heating control from the start of rice cooking to the spotty heating based on the temperatures detected by the pan sensor 9 and the lid sensor 29, the induction coils 6 and 7, the body heater 30.
And a rice cooking control means for the lid heater 28.
This rice cooking control means 61 is a hot water cooking control means 62 for hot water cooking for a predetermined time after the start of rice cooking, a heating control until boiling detection is completed after completion of hot water cooking, and a boiling detection after boiling is detected. The main rice cooking control means 63 performs stable control, and the uneven heating control means 64 performs uneven heating after completion of cooking detection. Further, reference numeral 65 is a failure detecting means for stopping the heating operation by determining that the pan sensor 9 or the lid sensor 29 is in a failure state such as disconnection when the detected temperature is lower than a predetermined temperature.
The failure detecting means 65 starts detecting the failure of the pan sensor 9 after the hot water cooking control means 62 of the rice cooking control means 61 starts to cook the rice, and when the detected temperature of the pan sensor 9 is equal to or lower than a predetermined temperature, The uneven heating is started by the pan sensor failure detecting means 66, which is the first failure detecting means for stopping the heating of the induction coils 6, 7, the body heater 30, and the lid heater 28, and the uneven heating control means 64 of the rice cooking control means 61. Later, the lid sensor 29
Failure detection is started, and when the temperature detected by the lid sensor 29 is below a predetermined temperature, the heating of the induction coils 6, 7, the body heater 30 and the lid heater 28 is stopped. And a detection means 67. further,
The hot water cooking control means 62 can detect boiling in the pan 4 based on the temperature detected by the pan sensor 9 so that the rice cooking operation can be continued until the uneven heating, even if the lid sensor 29 has previously failed. It is like this.

Next, regarding the rice cooker having the above-mentioned structure, the operation thereof will be described with reference to the graph of FIG. 4 showing the disconnection between the induction coils 6, 7 and the body heater 30 and the lid heater 28, and the flow chart shown in FIG. Explain. Cook rice and water in a pan 4
Then, the pot 4 is placed in the inner frame 2 and the lid 21 is closed. When the operation switch 47 is pressed to start the rice cooking control (step S1), the process proceeds to step S2, and the hot water cooking control means 62 constituting the rice cooking control means 61 performs the hot water cooking process. In this hot water cooking process, first, the induction coils 6 and 7 are energized at a low output of about 500 W for 1 second to determine the presence or absence of the pot 4, and when it is determined that the pot 4 is not housed in the inner frame 2. Immediately shifts to the off state. On the other hand, when it is determined that the pot 4 is housed in the inner frame, the temperature detected by the pot sensor 9 is changed in step S3 while the induction coils 6 and 7 are turned off for 29 seconds. Stabilize, and after the 30-second pan detection period ends, start hot water heating, which is the temperature-raising period of the pan sensor 9, while energizing the induction coils 6 and 7 with 800 W output for 50 seconds / 10 seconds. To do. The hot water cooking control means 62 is
It is determined in step S4 whether or not 60 seconds have elapsed after the start of this hot-boiled heating. If 60 seconds have elapsed, it is determined that the pot sensor 9 has heated to some extent, and thereafter,
At any time, the pan sensor failure detection means 66 is caused to detect the failure of the pan sensor 9. That is, the pot sensor failure detection means 66
Determines in step S21 whether the temperature detected by the pan sensor 9 is lower than -20 ° C. At this time, if the temperature detected by the pan sensor 9 is lower than −20 ° C. and continues for 1 second or more, the pan sensor failure detection means 66 determines that the pan sensor 9 has failed due to a disconnection or the like, and controls the rice cooking control means 61. Prior to giving priority to the above, the operations of the induction coils 6, 7, the body heater 30, and the lid heater 28 are forcibly stopped (step S
22). Further, the pan sensor failure detection means 66 allows the pan sensor 9 to be displayed via the LCD / LED display means 53 which is the display means.
Indicates that a failure has occurred (step S23), and the operation switch 47 is locked in order to prevent the user from operating again. On the other hand, step S2
In 1, when the temperature detected by the pan sensor 9 is -20 ° C or higher, it is determined that the pan sensor 9 is normal, and the control subsequent to step S5 is preferentially executed.

After step S2, the hot water cooking control means 62
When the hot water cooking process by 15 minutes has passed (step S
5) The process moves to step S6, and the rice cooking control means 61 continues the heating control process by the main rice cooking control means 63. In the heating control process, the induction coils 6 and 7 are continuously energized with an output of 1200 W to heat the cooked food in the pan 4, but in the next step S7, the temperature rise rate of the lid sensor 29 is 60%. When the temperature falls below 2 ° C. in a second or when the temperature detected by the pan sensor 9 is kept at 105 ° C. for 180 seconds, it is determined that the boiling detection in the pan 4 is completed, and the stable control step in step S8 is started. Transition. In this stable control process, the induction coils 6 and 7 are 10 W at 1000 W output.
Repeat the operation of energizing for 5 seconds and disconnecting for 5 seconds, and at the same time, dissipate the heat
In order to prevent dew condensation on 24, the body heater 30 and the lid heater 28 also repeat the operation of energizing for 30 seconds / powering off for 30 seconds to remove the lid 21.
The heat radiating plate 24 constituting the lower surface of the is heated (step S
9). Then, in step S10, when the temperature detected by the pan sensor 9 reaches 120 ° C., it is determined that the inside of the pan 4 has been cooked, and instead of the main rice control means 63,
The unevenness stroke based on the unevenness heating control means 64 is performed (step S11).

When the purging stroke is started, the purifying heating control means 64 causes the lid sensor failure detection means 67 to detect the lid sensor at any time.
Let 29 detect faults. That is, the lid sensor failure detection means 67 determines in step S31 whether the temperature detected by the lid sensor 29 is less than -20 ° C. At this time, if the temperature detected by the lid sensor 29 is lower than -20 ° C. and continues for 1 second or longer, the lid sensor failure detection means 67 determines that the lid sensor 29 has failed due to disconnection, and the rice cooking control means.
Induction coils 6, 7, body heater, prioritizing control over 61
The operations of 30 and lid heater 28 are forcibly stopped (step S32). Further, by the lid sensor failure detection means 67,
A display indicating that the lid sensor 29 has failed is displayed via the LCD / LED display means 53 (step S3).
3) Lock the operation switch 47. In this case, LCD
It is preferable that the failure display of the / LED display means 53 is different from the display mode when the pan sensor 9 is in failure, because the failure location can be immediately determined. On the other hand, in step S31, if the detected temperature of the lid sensor 29 is -20 ° C or higher, it is determined that the lid sensor 29 is normal,
Then, the control after step S11 is preferentially executed.

In the Murashi process, the induction coils 6, 7 are heated and controlled so that the temperature detected by the pan sensor 9 is 101 ° C., and the lid heater 28 is controlled so that the temperature detected by the lid sensor 29 is 110 ° C. And the body heater 30 is heated and controlled. Then, in step S12, when the purging stroke continues for 15 minutes, a series of heating control by the rice cooking control means 61 ends, and the heat retention step of step S13 is executed by the heat retention control means (not shown).

In the present embodiment, the failure detection of the pan sensor 9 capable of immediately detecting the temperature rise of the pan 4 is performed immediately after the start of rice cooking, and the failure detection of the lid sensor 29 which cannot immediately detect the temperature rise of the pan 4 is steamed and heated. The point to be done immediately after the start is noticed. In this case, if the lid sensor 29 has previously failed, the pot 4
On the other hand, since the detection is performed based on the temperature detected by the pan sensor 9 contacting the pan 4 instead of the non-contact lid sensor 29, the detection accuracy may be slightly deteriorated due to the influence of contact, but the rice cooking operation is continued. The heating is stopped by the failure detection of the lid sensor failure detection means 67 after the purging process is started. However, when this heating is stopped, the rice has already absorbed water and cooked, so the rice in the pan 4 is edible even though it has not been spotted. . Further, the step S32
If a lid sensor 29 failure is detected at
Only the heating of 30 and the lid heater 28 is stopped to continue the unevenness, and when the predetermined unevenness time in step S12 has elapsed, the heating of the induction coils 6, 7, the body heater 30 and the lid heater 28 is stopped. If the rice-cooking control means 61 is configured as described above, it is possible to finish the food in a sufficiently edible state although there is dew condensation on the heat dissipation plate 24. Furthermore, when boiling detection is performed based on the rate of increase in the temperature detected by the lid sensor 29 as in the present embodiment, it is not necessary to energize the lid heater 28 from the beginning of rice cooking to detect disconnection of the lid sensor 29.
It is also possible to avoid that the detection temperature of 29 becomes high and the accuracy of boiling detection deteriorates. On the other hand, the disconnection detection of the pan sensor 9 is performed by the pan sensor failure detection means 66 at the beginning of the hot water cooking process in which the temperature in the pan 4 has not risen so much. Even if the heating of the body heater 30 and the lid heater 28 is stopped, it is possible to re-cook rice by another means without any problem.

As described above, the rice cooker of the present embodiment corresponds to claim 1, the pan 4, the induction coils 6 and 7 for heating the pan 4, and the pan sensor 9 for detecting the temperature of the pan 4. A lid 21 that covers the upper opening of the pot 4, a lid sensor 29 that detects the temperature of the lower surface of the lid 21, and the start of rice cooking to the spotty heating based on the temperatures detected by the pot sensor 9 and the lid sensor 29. Rice cooking control means 61 for performing heating control on the induction coils 6 and 7,
After the rice cooking control means 61 starts cooking rice, the pan sensor 9 starts detecting a failure, and when the temperature detected by the pan sensor 9 is below a predetermined temperature, the heating of the induction coils 6 and 7 is stopped. Then, the failure detection of the lid sensor 29 is started after the start of the uneven heating by the rice cooking control means 61.
Since the lid sensor failure detecting means 67 for stopping the heating of the induction coils 6 and 7 is provided when the detected temperature of 29 is below a predetermined temperature, the failure due to the disconnection of the pan sensor 9 or the lid sensor 29 or the like. Is detected without malfunction, and even if the rice cooking operation is stopped midway, the rice to be cooked in the pan 4 is in the initial state of hot water cooking or after cooking, so it can be cooked raw as before. Without becoming inedible
It is possible to minimize the effect on the user.

Further, as an effect of the embodiment, in the structure of the above-mentioned claim 1, when the failure detection of the lid sensor 29 is started after the start of the uneven heating, and the detected temperature of the lid sensor 29 is equal to or lower than a predetermined temperature. In addition, by providing the lid sensor failure detection means 67 for unevenly heating the induction coils 6 and 7 and stopping after the completion of heating, when the lid sensor 29 fails, the rice in the pan 4 is sufficiently edible just before the heat retention. It can be in the state at the end of possible unevenness.

The present invention is not limited to the above embodiments, but various modifications can be made within the scope of the gist of the present invention. For example, as shown in the examples,
It goes without saying that the present invention can be applied to rice cookers other than the induction heating system using the induction coils 6 and 7 as the pot heating means.

[0021]

The rice cooker of the present invention comprises a pot, a pot heating means for heating the pot, a pot temperature detecting means for detecting the temperature of the pot, and a lid for covering the upper opening of the pot. The lid temperature detecting means for detecting the temperature of the lower surface of the lid body, and the heating control from the start of rice cooking to the uneven heating based on the temperatures detected by the pot temperature detecting means and the lid temperature detecting means are performed on the pot heating means. After the rice cooking control means and the rice cooking control means start to cook rice, the failure detection of the pan temperature detecting means is started, and the heating of the pan heating means is stopped when the temperature detected by the pan temperature detecting means is below a predetermined temperature. Failure detection of the lid temperature detection means is started after the start of the uneven heating by the first failure detection means and the rice cooking control means, and when the detected temperature of the lid temperature detection means is below a predetermined temperature, the pot heating means The second to stop heating Are those with a disability detection means, it is possible to prevent the failure of the pot temperature detecting means or the lid temperature detecting means even if it is detected during the cooking operation, it becomes edible disabled.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rice cooker showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the same.

FIG. 3 is a block diagram showing a processing procedure of a control sequence of the above.

FIG. 4 is a graph showing temperature change and on / off control.

FIG. 5 is a flowchart from rice cooking to heat retention.

[Explanation of symbols]

 4 Pan 6,7 Induction coil (pot heating means) 9 Pan sensor (pot temperature detection means) 21 Lid 29 Lid sensor (lid temperature detection means) 61 Rice cooking control means 66 Pan sensor failure detection means (first failure detection means) ) 67 Lid sensor failure detection means (second failure detection means)

Claims (1)

[Claims] 1. A pot and a pot heating means for heating the pot,
A pot temperature detecting means for detecting the temperature of the pot, a lid for covering the upper opening of the pot, a lid temperature detecting means for detecting the temperature of the lower surface of the lid, the pot temperature detecting means and the lid temperature detecting Based on the detected temperature of the means, the rice cooking control means for performing heating control from the rice cooking start to the spot heating to the pot heating means, and the failure detection of the pot temperature detecting means is started after the rice cooking is started by the rice cooking control means, A first failure detecting means for stopping heating of the pan heating means when the detected temperature of the pan temperature detecting means is equal to or lower than a predetermined temperature, and a failure of the lid temperature detecting means after the start of uneven heating by the rice cooking control means. A rice cooker comprising: a second failure detecting means for starting detection and stopping heating of the pot heating means when the temperature detected by the lid temperature detecting means is equal to or lower than a predetermined temperature.