JP2008061729A - Rice cooker with warmer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the continuation of a heat-retaining operation for a long period of time despite a lack of an inner pot by periodically detecting a small object even in retaining a heat in a rice cooker with warmer with a small object detecting function. <P>SOLUTION: An upper opening part of a rice cooker body 20 with an opened upper face is openably covered with a lid 21, the inner pot 1 is detachably stored in the rice cooker body 20, a unidirectional power supply 22 obtained by rectifying a commercial power supply 3 is converted into a high-frequency power by an inverter circuit 8 and the inner pot 1 is induction-heated by a heating coil 2. A control means 27 controls the inverter circuit 8 to appropriately cooked objects and execute rice cooking and warming, a current control means 25 controls a current to become a prescribed current value based on a value acquired from a current detecting means 24 for detecting the current supplied from the commercial power supply 3, and a small object detecting means 26 detects the presence/absence of the inner pot 1 and a small object load when induction-heating. This rice cooker/warmer further includes a heat-retained small object monitoring means 28 periodically induction-heating when retaining the heat and detecting the small object. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a jar rice cooker having an accessory detection function.

  2. Description of the Related Art Conventionally, in a jar rice cooker that induction-heats an inner pot, functions such as detection of small loads such as aluminum pots, spoons, knives, etc. other than predetermined inner pots and detection of no pan are added (for example, Patent Document 1). reference). FIG. 15 shows a configuration of a conventional jar rice cooker, and the configuration will be described below.

  As shown in FIG. 15, the inner pot 1 is heated by electromagnetic induction by the heating coil 2 with the cooked food inside. AC is supplied from the commercial power source 3 and rectified by the diode bridge 4. A high frequency power for induction heating is generated by an inverter circuit 8 including a smoothing capacitor 5, a resonance capacitor 6, and a transistor 7. The power value is controlled by controlling the power supply current. First, the power source current Iin is input to the primary side of the current transformer 9, the output value on the secondary side of the current transformer 9 is divided by a resistor, rectified by the diode bridge 10, and smoothed by a capacitor. An analog-digital conversion input (hereinafter referred to as AD input) is input to 11 input terminals to control the power value. The collector-emitter voltage Vce of the transistor 7 is divided by a resistor and AD input to the microcomputer 11 through the transistor 12.

  The microcomputer 11 performs an accessory detection process depending on the difference in the Vce-Iin characteristic due to the induction heating load. When the rice cooking switch 13 is pressed and rice cooking is started, the microcomputer 11 immediately turns on the IH, AD-inputs the collector-emitter voltage Vce of the transistor 7 and the power source current Iin, and performs small object detection.

FIG. 16 is a graph of the collector-emitter voltage Vce and the power supply current Iin of the transistor 7 input to the microcomputer 11 of the conventional jar rice cooker. As is clear from FIG. 16, the Vce-Iin characteristic for small items and the Vce-Iin characteristic for pots are separated from the straight line 1 as a boundary, and small items are detected using this characteristic. In addition, since it becomes a characteristic away from the straight line 1 when the aluminum pan is put when there is no pan, it can be detected that there is no pan.
Japanese Laid-Open Patent Publication No. 2-198110

  However, in such a conventional configuration, small objects can be detected only when induction heating is on, and induction heating is high thermal power, especially during heat retention that requires delicate temperature adjustment with weak thermal power, When thermal power control is performed by duty control, the on-time of induction heating is shortened to realize weak thermal power, and as a result, the time during which induction heating is not performed becomes considerably long. Therefore, the time during which small objects cannot be detected is extended for a long time, and when the induction heating is turned off, the pan is taken out and no pan can be detected. There has been a problem that the operation of keeping warm for a long time has occurred.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and it is an object of the present invention to periodically detect small objects even when keeping warm, and to eliminate the fact that the warming operation is continued for a long time even when there is no inner pot. .

  In order to achieve the above-mentioned object, the present invention covers the upper surface opening of the rice cooker body with the upper surface openable by a lid, and detachably houses the inner pot in the rice cooker body, and the inner pot is heated by a heating coil. A unidirectional power supply obtained by induction heating and rectifying the commercial power supply is converted into high-frequency power by an inverter circuit having a switching element, a resonance capacitor, and a smoothing circuit, and the inverter circuit is controlled by a control means to appropriately heat cooking. The rice is cooked or kept warm and controlled by the current control means so that the current becomes a predetermined current value based on the value obtained from the current detection means for detecting the current supplied from the commercial power source. The presence or absence of small objects and the small object load are detected by the small object detection means, and the insulated small object monitoring means for detecting small objects by periodically performing induction heating during the heat insulation is provided.

  Thereby, it is possible to periodically detect small objects during the heat insulation, and it is possible to eliminate the fact that the heat insulation operation is continued for a long time even when there is no inner pot.

  The jar rice cooker of the present invention can periodically detect small objects during the heat retention, and can eliminate the heat retaining operation for a long time despite the absence of the inner pot.

  1st invention is the rice cooker main body with which the upper surface opened, the lid | cover which covers the upper surface opening part of the said rice cooker main body openably, the inner pot detachably accommodated in the said rice cooker main body, and the said inner pot A heating coil for induction heating, a unidirectional power supply obtained by rectifying a commercial power supply, an inverter circuit having a switching element, a resonant capacitor, a smoothing circuit and converting the unidirectional power supply to high frequency power, and the inverter circuit Control means for controlling and heating the cooked food to cook rice and keeping warm, current detection means for detecting current supplied from a commercial power source, and a current based on a value obtained from the current detection means Current control means for controlling the current value, an accessory detection means for detecting the presence or absence of an inner pot and an accessory load at the time of induction heating, and an accessory monitoring means for detecting the accessory by performing induction heating periodically at the time of heat insulation With Because the induction heating is turned on periodically even when the induction heating is turned off during the heat retention, the rice cooker body is stored in a predetermined inner pot, or an aluminum pan other than the predetermined inner pot, a spoon Detects the presence of an inner pan and the load of small objects by detecting the inverter circuit waveform that changes depending on whether there is a small load such as a knife or no pan, and the input value change of the current detection means. Detection can be performed, and it is possible to eliminate the fact that the heat-retaining operation is continued for a long time even when there is no inner pot.

  According to a second invention, in the first invention, a lid opening / closing detecting means for detecting opening / closing of the lid and a stopping means for stopping operation of the warming accessory monitoring means when the lid is closed are added. Since the inner pan cannot be taken when the is closed, it can be avoided that the stopping means stops the induction heating for the small object detection to perform extra heating.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a lid opening small object monitoring means for detecting small objects by performing induction heating when the lid changes from a closed state to an open state is provided. Since the inner pan is frequently taken at the moment when it is opened, small objects can be detected by performing induction heating when the lid is opened, and heating without a pan can be prevented.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, a closed lid monitoring unit that detects small items by performing induction heating when the lid changes from an open state to a closed state is added. Since there is a possibility that the lid may be closed without the inner pot, it is possible to detect the accessory by performing induction heating and prevent the heat retaining operation from being continued without the pot.

  According to a fifth invention, in any one of the first to fourth inventions, a power failure detection means for detecting a power failure and a power failure accessory monitoring means for detecting an accessory by performing induction heating when the power failure is restored. Yes, there is a possibility that the inner pan may be taken out at the time of a power failure. By performing induction heating at the time of power failure recovery, small items can be detected and the operation without the inner pan can be prevented.

  A sixth aspect of the invention is the invention according to any one of the first to fifth aspects, wherein an abnormal accessory monitoring means for detecting an accessory by performing induction heating when returning to the abnormal mode due to noise or the like is added. Yes, there is a possibility that the inner pan may be taken in the abnormal mode, so that it is possible to detect an accessory by performing induction heating at the time of return and prevent the operation without the inner pan.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a block diagram of a jar rice cooker according to Embodiment 1 of the present invention, FIG. 2 shows a cross-sectional view of the jar rice cooker, and FIG. 3 shows a partially blocked circuit of the jar rice cooker. FIG.

  As shown in FIGS. 1 and 2, the rice cooker body 20 has an open top surface, and a lid 21 covers the top opening of the rice cooker body 20 so as to be freely opened and closed. The inner lid 1 is detachably accommodated in the rice cooker body 20, and the inner pot is induction-heated by the heating coil 2. The unidirectional power supply 21 rectifies the alternating current supplied from the commercial power supply 3 and rectifies it by the diode bridge 4 as shown in FIG. High frequency power for induction heating is generated by an inverter circuit 8 including a smoothing capacitor 5, a resonance capacitor 6, and a switching element 7 based on a unidirectional power supply 22. The power supply current supplied from the commercial power source is detected by the current detection unit 24, and the current control unit 25 controls the power value by controlling the current to be a predetermined current value based on the value obtained from the current detection unit 24. is doing. The accessory detection means 26 performs detection using the value detected by the current detection means 24 and the output value of the inverter circuit 8 to detect the accessory such as an aluminum pan or a spoon or the absence of a pan. The control means 27 controls the inverter circuit 8 so as to control the thermal power to cook rice or keep warm. The insulated small article monitoring means 28 periodically performs induction heating even when the induction heating is turned off during the thermal insulation, and by detecting the small articles, the pan detection is not performed for a long time even during the thermal insulation. The warming operation is not performed for a long time.

  The lid opening / closing detection unit 29 detects the opening / closing of the lid 21, and the lid opening / closing detection switch 32 (see FIG. 3) is turned on / off, thereby detecting the opening / closing of the lid 21. The control board 30 performs various controls.

  The power value of the inverter circuit 8 is controlled by controlling the power supply current. That is, as shown in FIG. 3, the power supply current Iin is input to the primary side of the current transformer 9, the output value on the secondary side of the current transformer 9 is divided by a resistor, rectified by a diode bridge 10, and smoothed by a capacitor. Then, AD is input to the input terminal of the microcomputer 11 to control the power value. The Vce of the transistor constituting the switching element 7 is divided by a resistor and AD input to the microcomputer 11 through the transistor 12. The microcomputer 11 performs an accessory detection process depending on the difference in the Vce-Iin characteristic due to the induction heating load. Control of rice cooking and heat retention is performed by appropriately heating the inner pot 1 by controlling the IC 31 for IH control by the microcomputer 11.

  The operation of the above configuration will be described with reference to FIG. FIG. 4 is a flowchart showing the operation of the microcomputer 11 of the jar rice cooker of the present embodiment.

  In step 33 of FIG. 4, it is determined whether or not the heat is being maintained. If not, the process proceeds to step 34, where the time of the timer T is counted and the process is terminated. If the temperature is being kept, the process proceeds to step 35. In step 35, it is determined whether or not induction heating is turned off. If induction heating is not turned off, the process proceeds to step 34, the timer T is counted, and the process is terminated. When the induction heating is off, the process proceeds to step 36, where it is determined whether or not the value of timer T is 16 seconds or more. If the value of timer T is not 16 seconds or more, the process proceeds to step 34 and the timer T is counted. To finish the process. If it is longer than 16 seconds, the process proceeds to step 37. In step 37, the timer T is cleared, and in step 38, induction heating for detecting small objects is turned on for 1 second. In step 39, AD input for Vce is performed, and in step 40, AD input for Iin is performed. In step 41, an operation for detecting an accessory is performed, and in step 42, it is determined whether the operation result is larger or smaller than a certain value B, whether a pan is present or not. If there is no pan, the process proceeds to step 43, where the panless process is performed and the process ends. If there is a pan, the end process is performed as it is.

  As described above, in the present embodiment, since the warming accessory monitoring means 28 that periodically detects the accessory by performing induction heating at the time of the heat retention, the induction heating is periodically performed even when the induction heating is turned off at the time of the heat retaining. By turning on, the inverter that changes depending on whether the rice cooker body 20 is housed in a predetermined inner pot, or is loaded with small items such as aluminum pots, spoons, knives other than the predetermined inner pot, or no pan The waveform of the circuit 8 and the input value change of the current detection means 24 can be detected to detect the presence / absence of the inner pot 1 and the load of small items, and the small items can be detected periodically during the heat insulation, and there is no inner pot 1. Nevertheless, it is possible to eliminate the case where the heat retaining operation is continued for a long time.

  In this embodiment, the cycle is fixed (inductive heating is turned on for 1 second every 16 seconds). However, it goes without saying that the cycle may be varied depending on the heat retention process, temperature, and the like.

(Embodiment 2)
FIG. 5 shows a block diagram of a jar rice cooker according to Embodiment 2 of the present invention.

  As shown in FIG. 5, the lid opening / closing detection means 50 detects opening / closing of the lid 21, and the stopping means 51 stops the operation of the warming accessory monitoring means 28 when the lid 21 is closed. When is closed, the stopping means 51 stops the operation of the warming accessory monitoring means 28 so as not to perform periodic pan detection. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  The operation of the above configuration will be described with reference to FIG. FIG. 6 is a flowchart showing the operation of the microcomputer 11 of the jar rice cooker of the present embodiment. The operation from step 33 to step 43 is the same as that in the first embodiment, and the description thereof is omitted.

  In step 52 of FIG. 6, it is determined whether or not the lid 21 is closed. When the lid 21 is open, the process proceeds to step 33, and thereafter the same operation as in the first embodiment is performed. When the lid 21 is closed, the process proceeds to step 53. At step 53, the timer T is cleared, and the process ends.

  As described above, in the present embodiment, the lid opening / closing detection means 50 for detecting the opening / closing of the lid 21 and the stop means 51 for stopping the operation of the warming accessory monitoring means 28 when the lid 21 is closed are added. Since the inner pot 1 cannot be taken when the lid 21 is closed, it is possible to prevent the stopping means 51 from performing extra heating by stopping induction heating for detecting small items.

(Embodiment 3)
FIG. 7 shows a block diagram of a jar rice cooker according to Embodiment 3 of the present invention.

  As shown in FIG. 7, when the lid 21 changes from the closed state to the open state, the lid opening accessory monitoring means 60 performs induction heating by the warming accessory monitoring means 28 to detect the accessory. Other configurations are the same as those in the first or second embodiment, and the same reference numerals are given and description thereof is omitted.

  The operation of the above configuration will be described with reference to FIG. FIG. 8 is a flowchart showing the operation of the microcomputer 11 of the jar rice cooker of the present embodiment. The operation from step 33 to step 43 is the same as that in the first embodiment, and the description thereof is omitted.

  In step 61 of FIG. 8, it is determined whether or not the lid 21 is opened from the closed state. The operation proceeds to step 33 except when the lid 21 is changed from the closed state to the open state, and thereafter, the same operation as that in the first embodiment is performed. When the lid 21 is changed from the closed state to the open state, the routine proceeds to step 37, where the timer T is cleared at step 37, and at step 38, induction heating is turned on for 1 second for small object detection. Thereafter, the same accessory detection process as that in the first embodiment is performed.

  As described above, in the present embodiment, the lid 21 is opened because the lid small object monitoring means 60 for detecting small objects by performing induction heating when the lid 21 changes from the closed state to the open state is added. Since the inner pan 1 is frequently taken at an instant, small objects can be detected by performing induction heating when the lid 21 is opened, and heating without a pan can be prevented.

(Embodiment 4)
FIG. 9 shows a block diagram of a jar rice cooker according to Embodiment 4 of the present invention.

  As shown in FIG. 9, when the lid 21 changes from the open state to the closed state, the lid closed accessory monitoring means 70 performs induction heating by the warming accessory monitoring means 28 to detect the accessory. Other configurations are the same as those in the first or second embodiment, and the same reference numerals are given and description thereof is omitted.

  The operation of the above configuration will be described with reference to FIG. FIG. 10 is a flowchart showing the operation of the microcomputer 11 of the jar rice cooker of the present embodiment. The operation from step 33 to step 43 is the same as that in the first embodiment, and the description thereof is omitted.

  In step 71 of FIG. 10, it is determined whether or not the lid 21 is closed from the open state. Except when the lid 21 is changed from the open state to the closed state, the process proceeds to Step 33, and thereafter, the same operation as in the first embodiment is performed. When the lid 21 is changed from the open state to the closed state, the routine proceeds to step 37, where the timer T is cleared in step 37, and in step 38, induction heating is turned on for 1 second for small object detection. Thereafter, the same accessory detection process as that in the first embodiment is performed.

  As described above, in the present embodiment, since the lid closed accessory monitoring means 70 is added to detect the accessory by performing induction heating when the lid 21 changes from the open state to the closed state, the inner pot 1 is not provided. Since the lid 21 may be closed, small objects are detected by performing induction heating, and it is possible to prevent the heat retaining operation from being continued without a pan.

(Embodiment 5)
FIG. 11: shows the block diagram of the jar rice cooker of Embodiment 5 of this invention.

  As shown in FIG. 11, the power failure detection means 80 detects a power failure from the state of the commercial power supply 3, and the power failure accessory monitoring means 81 performs induction heating by the warming accessory monitoring means 28 at the time of recovery from the power failure. Detection is performed. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  The operation of the above configuration will be described with reference to FIG. FIG. 12 is a flowchart showing the operation of the microcomputer 11 of the jar rice cooker of the present embodiment. The operation from step 33 to step 43 is the same as that in the first embodiment, and the description thereof is omitted.

  In step 82 of FIG. 12, it is determined whether or not a power failure has been restored. The process proceeds to step 33 except when the power failure is restored, and thereafter the same operation as in the first embodiment is performed. At the time of power failure recovery, the process proceeds to step 37. In step 37, the timer T is cleared, and in step 38, induction heating for small object detection is turned on for 1 second. Thereafter, the same accessory detection process as that in the first embodiment is performed.

  As described above, in the present embodiment, the power failure detection means 80 for detecting a power failure and the power failure accessory monitoring means 81 for detecting an accessory by performing induction heating at the time of power failure recovery, the inner pot 1 Therefore, it is possible to detect small objects by performing induction heating at the time of power failure recovery, and to prevent the operation without the inner pot 1.

(Embodiment 6)
FIG. 13: shows the block diagram of the jar rice cooker of Embodiment 6 of this invention.

  As shown in FIG. 13, the accessory monitoring unit 90 at the time of abnormality detects the accessory by performing induction heating with the accessory monitoring unit 28 when returning to the abnormal mode due to noise or the like. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  The operation of the above configuration will be described with reference to FIG. FIG. 14 is a flowchart showing the operation of the microcomputer 11 of the jar rice cooker of the present embodiment. The operation from step 33 to step 43 is the same as that in the first embodiment, and the description thereof is omitted.

  In step 91 of FIG. 14, it is determined whether or not it is a return from the abnormality. The process proceeds to step 33 except when returning from an abnormality, and thereafter the same operation as in the first embodiment is performed. When returning from the abnormal state, the routine proceeds to step 37, where the timer T is cleared in step 37, and in step 38, IH is turned on for 1 second for small object detection. Thereafter, the same accessory detection process as that in the first embodiment is performed.

  As described above, in the present embodiment, since the accessory monitoring unit 90 at the time of abnormality is added to detect the accessory by performing induction heating when returning to the abnormal mode due to noise or the like, the inner pot 1 in the abnormal mode is added. Therefore, it is possible to detect small items by performing induction heating at the time of return, and to prevent the operation without the inner pot 1.

  As described above, the jar rice cooker according to the present invention can detect small items periodically during the heat insulation, and eliminates the necessity of continuing the heat insulation operation for a long time even when there is no inner pot. Therefore, it is useful as a jar rice cooker having an accessory detection function.

The block diagram of the jar rice cooker of Embodiment 1 of this invention. Cross section of the jar rice cooker Partial block diagram of the jar rice cooker The flowchart which shows the operation of the microcomputer of the same jar rice cooker The block diagram of the jar rice cooker of Embodiment 2 of this invention. The flowchart which shows the operation of the microcomputer of the same jar rice cooker The block diagram of the jar rice cooker of Embodiment 3 of this invention The flowchart which shows the operation of the microcomputer of the same jar rice cooker The block diagram of the jar rice cooker of Embodiment 4 of this invention. The flowchart which shows the operation of the microcomputer of the same jar rice cooker Block diagram of a jar rice cooker according to Embodiment 5 of the present invention The flowchart which shows the operation of the microcomputer of the same jar rice cooker Block diagram of a jar rice cooker according to a sixth embodiment of the present invention The flowchart which shows the operation of the microcomputer of the same jar rice cooker Partially block circuit diagram of a conventional jar rice cooker Graph of Vce and Iin input by AD to microcomputer of the same rice cooker

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner pan 2 Heating coil 3 Commercial power supply 5 Smoothing circuit 6 Resonance capacitor 7 Switching element 8 Inverter circuit 20 Rice cooker main body 21 Lid 22 Unidirectional power supply 24 Current detection means 25 Current control means 26 Small article detection means 27 Control means 28 Insulation monitoring means

Claims (6)

A rice cooker body having an open upper surface, a lid that covers the upper surface opening of the rice cooker body so as to be openable and closable, an inner pot that is detachably stored in the rice cooker body, and a heating coil that induction-heats the inner pot And a unidirectional power source obtained by rectifying a commercial power source, a switching element, a resonant capacitor, an inverter circuit having a smoothing circuit and converting the unidirectional power source into high frequency power, and controlling the inverter circuit for cooking. Control means for cooking rice or keeping warm by performing moderate heating, current detection means for detecting current supplied from a commercial power source, and so that the current becomes a predetermined current value based on the value obtained from the current detection means Jar rice cooker equipped with current control means to control, accessory detection means for detecting the presence or absence of an inner pan or accessory load at the time of induction heating, and thermal insulation accessory monitoring means for detecting accessories by periodically performing induction heating at the time of heat insulation . The jar rice cooker according to claim 1, further comprising lid opening / closing detection means for detecting opening / closing of the lid and stopping means for stopping operation of the warming accessory monitoring means when the lid is closed. The jar rice cooker according to claim 1 or 2, further comprising a lid open accessory monitoring means for detecting an accessory by performing induction heating when the lid changes from a closed state to an open state. The jar rice cooker of any one of Claims 1-3 which added the lid | cover closed accessory monitoring means which performs accessory heating and detects an accessory when a lid | cover changes from an open state to a closed state. The jar rice cooker of any one of Claims 1-4 which added the power failure detection means which detects a power failure, and the power failure accessory monitoring means which detects an accessory by performing induction heating at the time of a power failure recovery. The jar rice cooker according to any one of claims 1 to 5, further comprising an abnormal accessory monitoring means for detecting an accessory by performing induction heating when returning to an abnormal mode due to noise or the like.

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