JP2768330B2 - Electric rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric rice cooker having a heat radiating plate in a lid unit.

[0002]

2. Description of the Related Art Conventionally, a lid unit of an electric rice cooker is generally provided with a radiator plate forming a lid portion of an inner pot, and the radiator plate is provided with a lid heater or a rice cooker body provided on the radiator plate itself. The droplets generated on the heat radiating plate portion by being heated by the shoulder heater provided on the shoulder portion are evaporated to prevent the droplets from falling on the surface of the rice.

[0003]

However, in the case where the droplets are scattered by heating the radiator plate itself as in the prior art, the droplets are scattered relatively easily by increasing the heating temperature. On the other hand, heat radiation to the rice side causes problems such as so-called bonito (yellowing), easy drying, and white blur due to the drop of water droplets.

The present invention has been made in order to solve the above-mentioned problems, and is intended to make it possible to scatter droplets without heating by vibrating a heat radiating plate with high frequency vibrating means such as an ultrasonic vibrator. It is an object of the present invention to provide an electric rice cooker which prevents generation of bonito, drying, and white blurring of rice.

[0005]

Means for Solving the Problems In order to achieve the above object, the present invention comprises the following means for solving the problems.

That is, first, the electric rice cooker of the present invention is
An inner pan, a rice cooker main body that stores the inner pan, a lid unit provided at an upper portion of the rice cooker main body, a heat sink provided inside the lid unit and forming a lid portion of the inner pan, An electric rice cooker comprising: an inner pot placed thereon; and a heating means for heating the placed inner pot, wherein the electric rice cooker is provided with high-frequency vibrating means for high-frequency vibrating the radiator plate.

Therefore, when the high-frequency vibrating means is driven by, for example, a rice cooker control unit or the like, the radiator vibrates in response to the high-frequency oscillating means, and the droplets generated on the radiator portion are evaporated and scattered on the same principle as the humidifier. And put it back in the inner pot.

As a result, the drop of the liquid drops on the rice is eliminated, and the humidifying action by the steam is realized.

In this case, if the high-frequency vibrating means is constituted by an ultrasonic vibrator, the vibration sound of the heat radiating plate is inaudible to a person, quiet, and effective vaporization of liquid droplets can be obtained. it can.

In these cases, the high-frequency vibrating means such as the ultrasonic vibrator may be directly mounted on the heat radiating plate, or may be separately mounted via a vibrating plate to facilitate resonance.

Further, the high-frequency vibrating means such as the ultrasonic vibrator is driven intermittently in consideration of a droplet generation interval in a process in which a droplet is likely to cause a problem, such as a warming process. ing.

In this case, the liquid can be vaporized without waste according to the state of generation of the droplet in the heat retaining step or the like.

[0013] Further, the above configuration eliminates the need to increase the amount of heating of the lid heater of the radiator plate or the shoulder heater corresponding to the radiator plate.

[0014]

As described above, according to the electric rice cooker of the present invention, it is possible to efficiently vaporize and scatter the droplets on the heat radiating plate and its surrounding portion without increasing the amount of heating to the heat radiating plate. As it becomes possible, the droplets can be atomized or vaporized and returned to the rice again, so that the rice is cooked in a good cooked state without the occurrence of bonito, drying, and white blur as before. Can be provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIGS. 1 to 5 show the configuration and operation of an electric rice cooker according to Embodiment 1 of the present invention.

First, the electric rice cooker is configured to serve, for example, both rice cooking and heat retention. And, for example, FIG.
As shown in FIG. 5, a bottomed cylindrical inner case 3 made of a synthetic resin formed so that an inner pot (rice cooker) 2 made of stainless steel or the like capable of generating heat by eddy current can be set therein. The rice cooker 1 includes a cylindrical outer case 4 that supports a case (protection frame) 3. In addition, a lid unit 5 is provided on an upper portion of the rice cooking main body 1 so as to be openable and closable.

The bottom 3a of the inner case 3 is configured so that two sets of inner and outer work coils 7a and 7b can be fitted at predetermined intervals by first and second concentric ribs (not shown). The work coils 7a and 7b are joined to the inner and outer fitting surfaces in the radial direction via the first and second ribs via an adhesive.

The outer case 4 includes a cylindrical cover 4a formed of a synthetic resin plate, a synthetic resin shoulder 4b coupled to an upper end of the cover 4a, and a cover 4a. A bottom portion 4c made of synthetic resin connected to a lower end portion forms a bottomed cylindrical shape with a space 6 having a predetermined width formed between the bottom portion 3a of the inner case 3 and the bottom portion 3a of the inner case 3. As described above, an inner case 3 made of a synthetic resin having a bottomed cylindrical shape for setting the inner pot 2 so as to be able to be taken out is supported.

Below the bottom 3a of the inner case 3, there are provided work coils 7a, 7b and a coil base 8 which are respectively positioned vertically.

An operation panel section 15 is provided on the front side of the cover section 4a of the outer case 4, and an operation board 16 provided with a rice cooking control unit 50 and the like shown in FIG.

A control board 17 having a control circuit for controlling the energization of the work coils 7a and 7b by a rice cooker control unit 50 comprising a microcomputer on the operation board 16 is provided below the coil base 8. Is provided.

On the other hand, the coil stand 8 has a work coil supporting portion 8a which has a saucer-shaped inner case supporting surface and supports the work coils 7a and 7b, and a ferrite core formed on the work coil supporting portion 8a. It is composed of fitting grooves 9, 9 and legs 10, 10 provided below the work coil support portion 8, and is supported on the outer case bottom 4c by the legs 10, 10. On the outer peripheral surface of the side of the work coil supporting portion 8a of the coil stand 8, a pair of vertical wall structures are located on both sides of one end (outer peripheral end) of the ferrite core fitting grooves 9, 9,. Spacers 11, 11 are provided, and a ring-shaped magnetic shielding plate 12 is fitted and fixed from the lower side around the outer periphery of the spacers 11, with a predetermined interval kept therebetween.

Further, the ferrite core insertion grooves 9, 9,.
The ferrite cores 13 and 13 are formed, for example, so as to extend in the radial direction at intervals of 90 degrees in the circumferential direction, and penetrate vertically, and at predetermined intervals in the radial direction. Is fitted.

The inner case 3 has a bottom 3
a and the side wall 3b are integrally formed, and the bottom 3a
A center sensor storage space portion (fitting insertion hole) 27a penetrating vertically and concentrically is formed in the center portion and the center portion of the work coil support portion 8a of the coil stand 8, and is formed in the center sensor storage space portion 27a. In a state where it can be moved up and down vertically,
In addition, a center sensor 27 for detecting the set state of the inner pot and the temperature is always provided in a state of being upwardly biased by the coil spring 18.

The center sensor storage space 27a is formed in a cylindrical body 19 formed by a rib extending in both the upper and lower directions at the center of the coil stand 8, and a sensor cover 20 is fitted into a lower opening thereof. , Screws 21 are fixed to the pressure wall portion on one side of the cylinder body 19 on the coil stand 8 side.

As shown in FIG. 1, for example, the center sensor 27 is a thermistor for detecting the temperature of the inner pot 2 at a sensor holding portion at the upper end of the cylindrical sensor holder 22.
A (temperature sensor) 23 is provided, and a sensor cap 25 made of a metal material having good thermal conductivity sufficient to cover the thermistor 23 is integrally fitted and fixed to the upper end of the sensor holder 22. ing. In addition, the lower part is turned on according to the elevation of the sensor holder 22,
A reed switch 24 that is turned off and detects the set state of the inner pot 2 is provided.

On the other hand, the lid unit 5 has an outer cover 37 made of a synthetic resin,
The rubber packing 42 is fitted inside the outer peripheral edge 37a of the
And an inner frame portion 38 made of synthetic resin, which forms an engagement portion of the lid unit 5 with the upper edge 2a of the inner pot 2 via the inner frame portion 38, and is fitted into the inner frame portion 38 to form a lid portion of the inner pot 2 Is formed in a hollow structure in which a heat insulating material 46 is provided by the heat radiating plate 39.
The outer cover 37 and the heat radiating plate 39 are connected to each other at the outer peripheral edges 37 a and 39 a via the inner frame 38. As shown in detail in FIG. 2, a lid heater 43 for heating the heat radiating plate 39 for evaporating the droplets at the time of unevenness and keeping the temperature at a predetermined interval in the radial direction is provided on the upper surface side of the heat radiating plate 39. , 43... Are provided, and the ultrasonic vibrator 32 is directly bonded and fixed between the lid heaters 43, 43.

The ultrasonic vibrator 32 is connected to the above-mentioned rice cooking control unit 50 via an ultrasonic drive circuit 31 as shown in FIG. 3, and a flow chart of FIG. 4 and a time chart of FIG. As shown in the chart, the drive is performed continuously or intermittently for t seconds immediately before the end of the unevenness step and within the heat retention time of the heat retention step. When the ultrasonic vibrator 32 is driven, the radiator plate 39 vibrates at a high frequency, and the droplets adhered and condensed on the radiator plate 39 are vaporized and evaporated and scattered by the same principle as that of the humidifier. Will be returned.

The ultrasonic vibrator 32 is made of a polycrystalline ceramic or the like, and has a property of being "electrostrictive" which is deformed when electricity is applied. Therefore, by utilizing the “electrostriction”, the heat radiating plate 39 is vibrated by the ultrasonic vibrator 32 to give a vibration energy larger than the surface tension of the droplet (tsuyu) adhering to the heat radiating plate 39, thereby providing the heat radiating plate 39. That is, the upper droplet (tsuyu) can be scattered.

The lid unit 5 configured as described above is rotatably attached to the shoulder 4b of the outer case 4 via a hinge mechanism 40. A lock lever 41 that engages with a predetermined position of the lid unit 5 to open and close the lid unit 5 is provided.

In addition, approximately in the center of the lid unit 5,
A vapor discharge port 47 is formed penetrating in the up-down direction.
A rubber packing 48 is provided in the steam discharge port 47.
Are fitted, and a vapor discharge cylinder 49 is attached via the packing 48.

Next, FIG. 3 shows the overall configuration of the rice cooker control circuit system centered on the rice cooker control unit of the electric rice cooker.

In the figure, reference numeral 50 denotes a rice cooking control unit provided on the operation board 16 on the back side of the operation panel 15 on the front side of the outer case 4, and the rice cooking control unit 50 is mainly composed of a microcomputer, 2, a detection circuit section having various detection functions such as a set state and a temperature state, a control circuit section, an oscillation circuit section, and the like. The detection circuit section includes, for example, the inner pot 2 by the thermistor 23.
Is detected.

The control circuit system section includes a commercial AC power supply (100 V) 30 as an output control circuit,
It includes a rectifier diode bridge circuit 51, a choke coil 52, an inverter circuit (broken line portion) 61, a transistor drive circuit 58, and the rice cooking control unit 50 described above. After the current is rectified by the rectifying diode bridge circuit 51 and converted into a DC current, the DC current is supplied to an inverter circuit 61 via a choke coil 52 and a smoothing capacitor 56.

The inverter circuit 61 includes, in addition to the choke coil 52, the work coils 7a and 7b, and the smoothing capacitor 56, a switching transistor 54 connected in series to the work coils 7a and 7b, and a reverse polarity parallel connection to the switching transistor 54. And a resonant capacitor 53 connected in parallel to the work coils 7a and 7b. The switching transistor 54 of the inverter circuit 54
Are driven ON and OFF by an oscillation output from a transistor drive circuit 58 whose oscillation frequency is controlled by the rice cooking control unit 50. The transistor driving circuit 58 has, for example, an oscillation frequency of 25 kHz.
It is formed by a high-frequency oscillation circuit of a degree.

On the other hand, the rice cooking control unit 50 is connected to the ultrasonic vibrator 32 for exciting the heat sink through the ultrasonic vibrator driving circuit 31 as described above. Then, the detected temperature T of the thermistor 23 is inputted, and the ultrasonic vibrator driving circuit 31 corresponding to the rice cooking process of FIG.
However, the operation is appropriately controlled as described below.

The rice-cooking control unit 50 includes a control program for removing liquid droplets, for example, as shown in the flowchart of FIG. 4 (steps S _{1 to} S ₉ ), and as shown in FIG. Immediately t seconds before the end of the process, the condensed droplets (tsuyu) which are likely to be generated in the heat retaining process are removed from the peripheral portion 9a.
Are evaporated and scattered without increasing the heating temperature.

[0038] That is, first in step S ₁ in the flowchart of FIG. 4, it reads cooking process control data, the switch operation condition, the data of the internal temperature of the pot 2 (rice temperature) T and various.

[0039] Then, it is determined whether or not the current cooking process is in the "steaming process" in FIG. 5 in step S _2.

The stage of the results, already when the YES determination is shifted to "steaming process" in FIG. 5, further before the end of t seconds the current cooking process proceeds to step S ₃ is "steaming process" Is determined.

As a result, if the result is YES (t seconds before the end of the mura process), the process proceeds to step S ₄ to continuously drive the ultrasonic vibrator driving circuit 31 for t seconds so that the above-described heat radiation plate 39
Is vibrated at a high frequency, and the condensed droplets generated on the heat radiating plate 39 are sufficiently vaporized and scattered in the inner pan 2.

[0042] After that, the course of the t sec (t = 0) determined in step S _5, when YES (steaming process is completed) further proceeds to step S _6.

[0043] Then, the driving state of the ultrasonic transducer 32 from the continuous driving state at the same step S _6, it switched to the intermittent driving state, intermittently driving the ultrasonic transducer 32 in a subsequent step S _7. As described above, at the time immediately before the end of the "Mura-shi process", there is much water from the cooked state up to that point,
Even though the lid heater 43 has a heating and evaporating effect,
A considerable amount of droplets are condensed, and a relatively large number of leaves are formed on the heat sink 39.
Is around. Therefore, the mixture is evaporated and scattered as much as possible by continuous ultrasonic vibration, and then enters the "warming step" in FIG.

On the other hand, when the "heat keeping step" is started, the water content of the rice itself is reduced, and not so many droplets are generated. In addition, the "heating process" takes a long time.

Therefore, in this case, taking into account the generation interval of the droplets, the intermittent driving is performed at an appropriate timing corresponding to the interval, and the ultrasonic vibrator 32 is driven without waste to scatter the droplets. It is returned to the rice side to prevent drying and to prevent the white bokeh phenomenon of the rice caused by dropping of the droplets. As a result, since it is not necessary to raise the temperature of the heat radiating plate 39, it is possible to maintain a good-quality rice state without causing a dry state and white blurring, since the occurrence of pods does not occur.

[0046] Then, during the "heat retaining process", when the cancel switch is turned ON, it was determined in step S _8, in step S _9, or to stop the driving of the ultrasonic transducer 32 End control of.

(Embodiment 2) Next, FIG. 6 shows a configuration of a main part of an electric rice cooker according to Embodiment 2 of the present invention.

In this configuration, in the configuration shown in FIGS. 1 and 2, the ultrasonic vibrator 32 is not directly mounted on the heat radiating plate 39, but is mounted via a diaphragm 60 having a U-shaped cross section, so that more resonance is achieved. It is easy to do.

(Embodiment 3) Next, FIGS. 7 and 8 show a main part of an electric rice cooker and a configuration of a control circuit system according to Embodiment 3 of the present invention.

In this configuration, instead of the electromagnetic rice cooker having the work coils 7a and 7b according to the first embodiment as shown in FIGS. 1 and 2, a rice cook heater 68 and a rice cooker 68 as shown in FIG. In a heater type rice cooker having a heat retaining heater 69 and a shoulder heater 70 provided on the shoulder portion 4b of the rice cooker main body 1 instead of the lid heater 43 described above, a radiator plate 39 inside the lid unit 5 is provided. In contrast, the ultrasonic transducer 32 exactly the same as that of the first embodiment is attached, and the control as shown in FIG. 4 is performed by the control circuit system of FIG.

In this configuration, the outer peripheral edge 77 of the heat radiating plate 39 is provided.
Is bent downward in a hook shape and is brought into contact with the shoulder heater 70, so that the entire radiator plate 39 is heated via the corresponding contact portion.

In FIG. 7, reference numeral 51 denotes an outer cover of the lid unit 5, 52 denotes the inner cover, 75 denotes a heater plate, and 76 denotes a heat shield plate.

That is, as shown in FIG. 8, the ultrasonic vibrator 32 is connected to the above-mentioned rice cooking control unit 50 via the ultrasonic driving circuit 31, and the flowchart of FIG. As shown in the time chart of FIG. 5, the rice cooking control unit 50 is similarly continuously or intermittently driven within t seconds immediately before the end of the “irregularity process” and within the heat retention time of the “heat retention process”. It has become. Therefore, when the ultrasonic vibrator 32 is driven, the heat radiating plate 39 vibrates at a high frequency, and the droplets adhered and condensed on the heat radiating plate 39 are vaporized and evaporated and scattered on the same principle as the humidifier.

In FIG. 8, reference numeral 27 is a center sensor, 23 is a thermistor, 24 is a reed switch, 7
Numeral 1 is a triac for controlling the driving of the heat retention heater, 72 is a triac for controlling the driving of the shoulder heater, and SWa is a rice cooker switch.

Therefore, even with the above configuration, it is possible to realize exactly the same operation and effects as those of the first embodiment.

Further, in the case of this configuration, the lid unit 5 can be washed in a round manner.

(Embodiment 4) FIG. 9 is a flowchart showing the content of control for removing condensed droplets in a warming step of an electric rice cooker according to Embodiment 4 of the present invention.

In the case of the condensed droplet removal control of the first embodiment shown in FIG. 4 described above, immediately before the end of the “watering process”, a large amount of water has been generated from the cooked state up to that point, and the lid heater is temporarily turned off. Even though there is a heating and evaporating effect, a considerable amount of droplets condense and a relatively large number of leaves are around the heat sink. Therefore, this is vaporized and scattered as much as possible by continuous ultrasonic vibration, and then the control of the "warming step" is started.

Then, when the control of the "heat keeping step" is started, the water content of the rice itself is reduced, and not so many droplets are generated. In addition, the "warming process" itself takes a long time.

Therefore, in this case, taking into account the generation interval of the droplets, intermittent driving is performed at an appropriate timing corresponding to the interval, and the ultrasonic vibrator 32 is driven without waste to cause the droplets to scatter. In addition, the rice is returned to the rice side to prevent drying and to prevent the white bokeh phenomenon of the rice caused by dropping in a droplet state.

The control in the present embodiment is characterized in that the interval of the intermittent drive of the ultrasonic vibrator 32 after the transition to the heat retaining step is embodied.

[0062] That is, when the steaming process is completed, subsequently enters the incubating process, the first LED light for insulation status display in Step S _1. The insulation heater at Step S _3, S ₄ with correspondingly to OFF work coil in step S _2, and each OFF lid heater,
The temperature of the rice is quickly lowered to the set temperature of 72 ° C.

[0063] Then, the process proceeds to step S _5, and starts the timer operation of the first interval timer T ₁ for intermittently driving the ultrasonic transducer 32 (set time 32 seconds).

[0064] On top of that, then proceeds to step S _6, determines whether decreased to a temperature of the rice set retained temperature 72 ° C. or less.

As is clear from the characteristics shown in FIG. 5, during the predetermined time from the transition to the heat retaining step, the set heat retaining temperature 72
Since the temperature does not reach ℃ or lower, the above determination result is usually NO.

Therefore, the process proceeds to steps S ₇ , S ₈ , and S ₉ , while the OFF state of the heat retaining heater, the lid heater, and the work coil is continued, until the temperature falls to or below the set temperature at step S _10. monitoring the first interval setting time 32 seconds elapse of the timer T ₁ of the.

Then, the first interval timer T
When _one of the set time 32 seconds has elapsed (YE in Step S ₁₀
S), the process proceeds to step S _11, it drives the ultrasonic transducer 32 at one second predetermined frequency fa.

[0068] When the driving of the ultrasonic vibrator 32 is completed, it is started again in step S ₅ return newly to the first interval of the timer operation timer T ₁ in the, its setting time 32 seconds Until the temperature of the rice does not drop below the set warming temperature of 72 ° C. (YES in step S ₆ ), the intermittent driving of the ultrasonic vibrator 32 for one second is repeated at the above-mentioned 32 second intervals.

In this way, the relatively large amount of droplets generated during the period from the completion of the mura process to the temperature setting of 72 ° C. is smoothly vaporized and atomized at the corresponding short intervals. Returned to the rice side.

[0070] On the other hand, when the temperature of the rice is determined YES in step S ₆ decreases the set retained temperature 72 ° C. or less, under the step S ₁₂ following settings retained temperature 72 ° C. is hereinafter
Intermittent drive control of the first interval timer T ₁ of the set time 32 seconds compared to 1 second in considerably longer second interval setting time 288 seconds the timer T ₂ ultrasonic transducer 32 is performed.

That is, first, in step S ₁₂ , the second
To start the interval timer operation of the timer T _2.

[0072] Then, the process proceeds to step S ₁₃ is followed on its determines whether the state in which the temperature is set retained temperature 72 ° C. below the rice again.

As a result, if YES, step S ₁₄ ,
Proceeding to S ₁₅ and S ₁₆ sequentially, the whole of the rice is controlled by turning on the heat retention heater at a duty ratio of 8/16, the lid heater at a duty ratio of 2/16, and the work coil at a duty ratio of 1/16. Is heated uniformly to keep the temperature warm.

On the other hand, if NO, steps S ₁₇ and S _17
18, advances towards the S _19, the OFF the insulation heater, the ON lid heater with a small duty ratio of 1/16, and respectively control the work coil to OFF, the temperature is set retained temperature of the rice 72 Perform temperature control to reach ° C.

Next, while executing the heat retention control centered on the set heat retention temperature 72 ° C. as described above, step S
₂₀ monitors the elapse of the second interval timer T ₂ of the set time 288 seconds under the above settings retained temperature 72 ° C..

Then, the second interval timer T
When the _second set time 288 seconds elapses (Y in step S ₂₀
ES), the process proceeds to step S _21, the ultrasonic transducer 32
Is driven at a predetermined frequency fa for one second.

[0077] When the driving of the ultrasonic vibrator 32 is completed, is started again in step S ₁₂ return newly in the second interval timer operation of the timer T ₂ in the, the set time 288 seconds The intermittent drive of the ultrasonic vibrator 32 for one second is repeated every 288 seconds as described above.

As a result, the droplets having a relatively small amount generated in an appropriate heat-retaining state that has reached the set heat-retaining temperature of 72 ° C. are smoothly vaporized and atomized at long intervals corresponding thereto and returned to the rice side. .

The above control in this configuration is performed, for example, immediately before the end of the “irregularity process” in the first embodiment.
It may or may not be combined with the continuous drive control a few seconds before.

Further, the driving signal of the ultrasonic vibrator 32 driven for a predetermined time at the predetermined interval is, for example, a half-wave signal (normal phase driving) of a constant frequency (fa = constant) as shown in FIG. Alternatively, it may be a full-wave signal (both normal and reverse phase driving) having a constant frequency (fa = constant) as shown in FIG.

When the half-wave and full-wave drive signals as shown in FIGS. 10 and 11 are used, the frequency fa is gradually changed as the drive time t elapses as shown in FIGS. 12 and 13, for example. You can make it higher.
In this way, droplets having a large diameter are ejected at a relatively low vibration frequency in the initial stage of driving, and the remaining particulate water having a small diameter at a high vibration frequency thereafter can be reliably and uniformly dispersed throughout the heat radiation plate 39. This has the advantage of being able to be vaporized and scattered.

The frequency fa can be varied in an arbitrary pattern within the predetermined drive time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an electric rice cooker according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view of a main part of the electric rice cooker.

FIG. 3 is a control circuit diagram of the electric rice cooker.

FIG. 4 is a flowchart showing a control operation of the control circuit of FIG. 3;

FIG. 5 is a time chart showing rice cooking characteristics of the electric rice cooker.

FIG. 6 is a cross-sectional view showing a configuration of a main part of the electric rice cooker according to Embodiment 2 of the present invention.

FIG. 7 is a cross-sectional view showing a configuration of a main part of an electric rice cooker according to Embodiment 3 of the present invention.

FIG. 8 is a control circuit diagram of the electric rice cooker.

FIG. 9 is a flowchart showing the details of droplet removal control of the electric rice cooker according to Embodiment 4 of the present invention.

FIG. 10 is a signal waveform diagram showing a first example of an ultrasonic transducer drive signal used in the control.

FIG. 11 is a signal waveform diagram showing a second example of an ultrasonic transducer drive signal used in the control.

FIG. 12 is a signal waveform diagram illustrating a third example of an ultrasonic transducer drive signal used in the control.

FIG. 13 is a signal waveform diagram showing a fourth example of an ultrasonic transducer drive signal used in the control.

[Explanation of symbols]

2 is an inner pot, 3 is an inner case, 4 is an outer case, 5 is a lid unit, 7a and 7b are work coils, 8 is a coil stand, 23 is a thermistor, 39 is a heat sink, 32 is an ultrasonic vibrator, and 43 is A lid heater, 50 is a rice cooking control unit, 68 is a rice cooking heater, 69 is a warming heater, 70 is a shoulder heater, and 75 is a heater plate.

Claims (7)

(57) [Claims] 1. An inner pot, a rice cooker main body accommodating the inner pan, a lid unit provided on an upper portion of the rice cooker main body, and a lid portion of the inner pan provided inside the lid unit. In an electric rice cooker comprising a heat sink and a heating means for heating the placed inner pot while the inner pot is placed, high-frequency vibrating means for high-frequency vibrating the heat sink is provided. Characterized electric rice cooker. 2. The electric rice cooker according to claim 1, wherein the high frequency vibrating means is an ultrasonic vibrator. 3. The electric rice cooker according to claim 1, wherein the high-frequency vibration means is mounted on a heat sink. 4. The electric rice cooker according to claim 1, wherein the high-frequency vibrating means is attached to the heat radiating plate via a vibrating plate. 5. The electric rice cooker according to claim 1, wherein the high-frequency vibrating means is driven intermittently in the heat retaining step. 6. The electric power as claimed in claim 1, wherein the radiator plate is provided with a lid heater, and the radiator plate is heated by the lid heater. rice cooker. 7. The rice cooker main body is provided with a shoulder heater at a shoulder thereof, and the radiator plate is heated by the shoulder heater. An electric rice cooker as described.