JP2003257599A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an induction heating cooker having good heating efficiency and water absorption efficiency. <P>SOLUTION: In an induction coil 6, the direction of a generating force is reversed by applying current in a reversed direction by winding a side part induction coil 6a and a middle part induction coil 6b in reversed direction respectively. With this, a reversed direction force is generated at a part opposing to the side part induction coil 6a and a part opposing to the middle part induction coil 6b in a container 2, vibrations of high frequency are generated at a bottom surface of the container 2. With this high-frequency vibration, percentage of moisture content of a cooked food is increased, and also, high-frequency vibration can directly be impressed on water or rice, therefore, moisture- containing time can be reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating cooker, such as a rice cooker, for heating a container by an induction heating source to heat an object to be cooked in the container.

[0002]

2. Description of the Related Art FIG. 16 shows, for example, Japanese Patent No. 2874506.
It is sectional drawing of the induction heating type rice cooker which is the conventional induction heating cooker shown by the publication. In the figure, 51 is a rice cooker housing, 52 is a rice cooker installed in the housing 51, 53 is a heating coil as a heating means of the rice cooker 52, 54 is a first inverter for supplying electric power to the heating coil 53, Reference numeral 55 is an ultrasonic vibrator provided in contact with the side portion of the rice cooking pot 52, and 56 is a second inverter for supplying electric power to the ultrasonic vibrator 55, which constitutes an ultrasonic wave generating means together with the ultrasonic vibrator 55. There is something.

Next, the operation will be described. The ultrasonic vibrator 55, which is in contact with the rice cooking pot 52 when the water content of rice in the initial stage of rice cooking, is supplied with power by the second inverter 55,
Ultrasonic waves are generated in the rice cooking pot 52 independently of the heating of the rice cooking pot 52 by the first inverter 54. That is, by inputting ultrasonic waves when the rice contains water during the initial stage of rice cooking, the water content can be promoted to improve the rice cooking performance, and the rice cooking time can be shortened. Further, this ultrasonic input is performed simultaneously with the heating of the rice cooking pot 52, so that the optimum moisture content of rice can be obtained in a short time.

FIG. 17 is a sectional view of an induction heating type rice cooker which is a conventional induction heating cooker disclosed in Japanese Patent No. 2621328, for example. In the figure, 60 is a pot for storing food, 61 is a protective frame for placing and supporting the pot 60 on the flange portion at the upper end of the pan, 62 is a cooker main body in which the protective frame 61 is disposed, and 63 is a protector. It is an induction heating source that is placed outside the frame 61 and that induction-heats the pot 60.
At least one of which is an induction coil divided into a plurality of parts so as to induction-heat the corner portion of the bottom of the pan.

Next, the operation will be described. Since the bottom of the pan 60 is induction-heated by the induction coil divided into a plurality of parts, the temperature distribution becomes gentle due to the large number of induction coils that heat the bottom of the pan. Further, since the number of induction heating points by the plurality of induction coils is increased, the number of boiling points is increased, the temperature distribution in the top and bottom of the pot 60 is improved, and at least one induction coil induction-heats the corner portion of the pot bottom. Therefore, it is possible to always generate a boiling point at the corner of the bottom of the pot, and the convection caused by the boiling flows smoothly along the side surface of the pot 60 to the top of the pot 60, so that vertical convection can be performed smoothly. This makes it possible to further improve the temperature distribution in the pan 60 and reduce uneven cooking.

[0006]

The conventional induction heating cooker as described above requires the ultrasonic wave generating means having the ultrasonic vibrator 55, and thus becomes expensive and the cooker cannot be supplied inexpensively. However, there was a problem that its structure was complicated and it was difficult to assemble and maintain. In addition, since the bottom of the pot 60 is induction-heated with an induction coil that is divided into a plurality of parts, and at least one induction coil induction-heats the corner of the bottom of the pot, the heating distribution is good, but the efficiency of water absorption cannot be increased. There were problems such as.

The present invention has been made in order to solve the above problems, and provides an induction heating cooker having high heating efficiency and high water absorption efficiency.

[0008]

SUMMARY OF THE INVENTION An induction heating cooker according to the present invention is provided with a container of magnetic material for containing food and a spiral which is provided so as to oppose the outer circumference of the container and inductively heats the container by energization. A plurality of induction coils and control means for controlling current supply to the plurality of induction coils, and the direction of the high-frequency current flowing through at least one induction coil among the plurality of induction coils is different from that of the other induction coils. The container is energized in the direction opposite to the direction of the high-frequency current flowing therethrough to vibrate the container at high frequencies.

Further, a container made of a magnetic material for containing the food,
A plurality of spiral induction coils, which are provided so as to face the outer circumference of the container, at least one induction coil is wound in a direction opposite to that of the induction coil, and induction heats the container by energization, and the plurality of induction coils. And a control means for controlling current supply to the induction coil, and a high-frequency current is passed in the spiral direction of the plurality of induction coils to vibrate the container at a high frequency.

Further, the plurality of induction coils are electrically connected in series.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a sectional view of an induction heating cooker showing a first embodiment of the present invention, FIG. 2 is a plan view of an induction coil of the induction heating cooker, and FIG. 3 is a block diagram of a control circuit of the induction heating cooker. FIG. 4 is a chart showing the operation of this control circuit, and FIG. 5 is a plan view of another induction coil of this induction heating cooker.

In the figure, reference numeral 1 denotes a cooker main body, which is an example of a rice cooker. Reference numeral 2 denotes a bottomed cylindrical container having an outer surface made of a magnetic metal and having a flange portion on an upper portion and for housing an object to be heated. The flange portion has a protective frame 3 (described later).
Suspended at the top of the. Reference numeral 3 denotes a cylindrical protective frame that constitutes an opening for housing the container 2. The protective frame 3 includes an upper frame 3a, a side heat radiating plate 5 having a body heater 4 attached to the outer surface, and an induction coil 6 (described later) on the outer surface. It is composed of a coil base 7 to be supported, and is arranged so as to fit onto the upper portion of the cooker body 1.

Reference numeral 6 denotes a planar induction coil, which comprises a side induction coil 6a facing the bottom corner of the container 2 of the coil base 7 and a side induction coil 6b facing the bottom surface of the container 2. It has a spiral shape. 7a is a ferrite base projectingly arranged on the lower surface of the coil base 7, 8 is a bottom plate, 9 is a ferrite base 7a which is attached to the ferrite base 7a to protect the outside, and 11 is a central portion of the coil base 7. The bottom thermistor 11 is biased in the direction of the container 2 by the spring 10, and contacts the container 2 to indirectly detect the temperature of the object to be heated.

Reference numeral 12 denotes a lid disposed on the upper portion of the cooker body 1, and the hinge portion 3b integrally formed on the protective frame 3 supports the upper portion of the cooker body 1 via a shaft 13 so as to be openable and closable. To be done. A lid radiating plate 14 is attached to the lower portion of the inner surface of the lid body 12, and a lid heater 15 is attached to the inner surface of the lid radiating plate 14. A lid heat insulating material 16 is arranged inside the lid body 12.

Reference numeral 17 denotes an inner lid which is detachably attached to the lower surface of the lid 12, and a packing 18 is provided around the inner lid 17.
And the inner lid packing 18 contacts the container 2 and closes the container 2 when the lid 12 is closed. Reference numeral 19 is a lid thermistor attached to the heat dissipation plate 14 to detect the internal temperature of the inner pot 2 by penetrating the inner lid 17, and 20 is an induction coil based on the transmitted temperature information of the bottom thermistor 11 and the lid thermistor 19. 6, a control circuit for controlling the electric power of the body heater 4, the lid heater 15 and the like to cook rice and keep warm.

Next, regarding the detailed structure of the induction coil 6,
This will be described with reference to FIG. The induction coil 6 is divided into two and is configured to induction-heat the bottom of the container 2. The side induction coil 6a is spirally wound in the right-hand direction, and the middle induction coil 6b is spirally wound in the left-hand direction. The induction coil 6a is connected to the middle induction coil 6b and is composed of one conductor wire. Here, the side induction coil 6a and the middle induction coil 6
Since b is wound in the opposite direction, the directions of the currents flowing through both coils are opposite.

Next, the application of a current to the induction coil 6 and the vibration of the bottom surface of the container due to the application of the current will be described. First, the operation of the control circuit 20 will be described with reference to FIG. Electric power supplied from the commercial power supply 21 is converted into direct current by the rectifier 22 and the smoothing capacitor 23. The induction coil 6 and the resonance capacitor 24 are connected in parallel, one end of which is connected to the + (plus) pole side of DC, and the other end of which is connected to the collector terminal of the switching element 25 in which a diode is reversely connected. The emitter terminal of the switching element 25 is connected to the- (minus) pole of the DC power supply, and by applying a voltage to the gate terminal of the switching element 25, the emitter-collector terminal becomes conductive and current flows through the induction coil 6.

The VCE zero-cross detection circuit 26 compares the voltages across the induction coil 6 and sends out a signal near zero volts, and the control means 27 drives the ON signal of the switching element 25 by the signal from the VCE zero-cross detection circuit 26. The signal is sent to the circuit 28, and the switching element 25 is driven by the drive circuit 28. Further, the control means 27 controls heating based on the temperature information from the temperature detecting means 29 connected to the bottom thermistor 11 and the lid thermistor 19, and performs the cooking operation.

Next, the operation of the switching element 25 will be described with reference to FIG. By turning on and off the gate voltage of the switching element 25, an alternating high-frequency current flows through the induction coil 6 as shown in the figure. When the gate voltage of the switching element 25 is turned off, an emitter voltage is generated at the emitter terminal of the switching element 25. To prevent loss of the switching element 25, the VCE zero-cross detection circuit 26 detects a drop in the emitter voltage and After the voltage drops, the next ON operation of the gate voltage is performed.

As described above, in the induction heating cooker, a high frequency current is passed through the induction coil 6, an eddy current is generated in the container 2 by the generated magnetic field, and the container 2 is heated by Joule heat generated by the eddy current.
Generates heat and heats the food. At this time, a force is generated at the same time as the magnetic field due to the current, but the directions of the magnetic field and the force are determined by the direction of the current based on Fleming's left-hand rule.
In this case, the side induction coil 6a and the middle induction coil 6
By passing a current in the opposite direction to b, the magnetic field and the force are opposite.

That is, in the induction coil 6, the side induction coil 6a and the middle induction coil 6b are wound in the opposite directions to flow currents in the opposite directions, whereby the directions of the generated forces can be reversed. . As a result, the container 2 has a portion facing the side induction coil 6a and the middle induction coil 6a.
A force in the opposite direction is generated at the part where b is opposed, and high-frequency vibration can be generated on the bottom surface of the container 2. The high frequency vibration of the bottom surface of the container 2 improves the water content of the cooked product (rice), and since the high frequency vibration can be directly applied to water or rice, the effect of improving the water content and shortening the water content time becomes large. .

As described above, according to the first embodiment, a plurality of induction coils are wound in opposite directions, a high-frequency current is passed in the opposite directions, and the direction of the force generated on the container is set in the opposite direction. Thereby, high-frequency vibration can be generated on the bottom surface of the container 2, the moisture content of the cooked food (rice) can be improved, and the moisture content time can be shortened.

In the first embodiment, the induction coil 6 has two spiral shapes. However, as shown in FIG. 5, the induction coil 6 includes the first induction coil 6c and the second induction coil 6c.
The third induction coil 6d and the third induction coil 6e may be formed in three spirals, and the second induction coil 6d may be wound in the reverse direction of the first induction coil 6c and the third induction coil 6e. , When a current is applied to the induction coil 6,
In the container 2, a force in the opposite direction is generated between the part facing the first induction coil 6c and the third induction coil 6e and the part facing the second induction coil 6d, and high-frequency vibration is generated on the bottom surface of the container 2. It can be caused, and the same effect as the above can be obtained.

In the first embodiment, the side induction coil 6a and the middle induction coil 6b are connected in series, but they may be connected in parallel and controlled so that current flows in the opposite direction. Needless to say, the same effect can be obtained.

Further, in the first embodiment, the side induction coil 6a and the middle induction coil 6b are connected to each other and controlled by one switching element 25. However, the side induction coil 6a and the middle section are controlled. It is needless to say that the induction coil 6b may be made independent, and the respective switching elements may be controlled so as to pass current in the opposite directions, and the same effect is obtained.

In the first embodiment, the case where the invention is applied to the rice cooker is described as a specific example of the induction heating cooker, but the invention is not limited to the rice cooker, and for example, a cooking heater (electromagnetic cooker) is used. It may be implemented in a container such as a pot, which is installed on the heater top panel and is made of a magnetic metal material, in the side induction coil 6a and the middle induction coil 6b, or the first induction coil 6c, the second induction coil 6d and the third induction coil 6d. The part of the bottom surface facing the induction coil 6e can be induction-heated and high-frequency vibration can be generated on the bottom surface, and the same effect as described above can be obtained.

In the first embodiment, the side induction coil 6a and the middle induction coil 6b, the first induction coil 6c, the second induction coil 6d and the third induction coil 6 are also included.
Although the e is arranged concentrically, it is not limited to this and may be arranged separately as shown in FIG.

FIG. 6 is a plan view of another induction coil of the induction heating cooker according to the first embodiment of the present invention. In the drawing, the induction coil 6 is divided into four, and the right-handed induction coil 6f, It consists of a left-handed induction coil 6g, a right-handed induction coil 6h, and a left-handed induction coil 6i. These four induction coils are arranged so as to face the bottom surface of the container. Therefore, in each induction coil, the energization of the high-frequency current is controlled by one switching element or a switching element corresponding to each induction coil to induction-heat the container, and a portion facing the right-handed induction coil 6f and the induction coil 6h. And left-handed induction coil 6e and induction coil 6i
A force in the opposite direction is generated at the portion facing to, and high-frequency vibration can be generated at the bottom surface of the container 2, and the same effect as above can be obtained.

Embodiment 2. In the second embodiment, the shape of the induction coil that matches the container shape of the induction heating cooker will be described.

FIG. 7 is a sectional view of an induction heating cooker showing a second embodiment of the present invention, and FIG. 8 is a perspective view of an induction coil 6 of the induction heating cooker. In the figure, parts that are the same as or correspond to those in Embodiment 1 above are given the same reference numerals, and descriptions thereof are omitted. The induction coil 6 is divided into two parts, a side induction coil 6a and a middle induction coil 6b, for induction heating the bottom of the container 2, and the side induction coil 6a faces the corner of the container 2 and is substantially parallel. It is formed in a curved shape whose outer side is raised so as to have a shape, and the middle induction coil 6b is formed in a flat shape so as to face the bottom surface of the container 2. further,
The side induction coil 6a is wound in a right-handed manner and the middle coil 6b is wound in a left-handed manner.
To the middle induction coil 6b and is composed of one conductor wire.

Next, the operation will be described. Control circuit 2
The high-frequency current is applied to the induction coil 6 by 0 in the same manner as in the first embodiment. Since the side induction coil 6a and the middle induction coil 6b are wound in opposite directions, the current flowing through both coils is reduced. The direction is opposite. Furthermore, as described above, the induction coil 6 is divided into two and is configured to inductively heat the bottom of the container 2. Particularly, the side induction coil 6a is formed in a curved shape, and the side induction coil 6a is provided on the outer peripheral side of the bottom of the container 2. It is arranged along the corner. Therefore, by energizing the induction coil 6, the corner portion of the container 2 is moved by the side induction coil 6a.
The bottom of the container 2 is induction-heated by the middle induction coil 6b, and the force applied to the container 2 can be reversed between the corner and the bottom, and the force is applied with the contact point between the corner of the container 2 and the bottom plane as a fulcrum. Therefore, the container 2 can be efficiently vibrated.

As described above, according to the second embodiment, the curved side induction coils 6a are arranged at the corners of the container 2, and the middle induction coil 6b is arranged at the bottom of the container 2 so that the directions of the respective currents are changed. Since it is in the opposite direction, the force applied to the container 2 can be reversed at the corner portion and the bottom portion, and the force can be applied with the contact point between the corner portion and the bottom flat surface of the container 2 as a fulcrum, thereby efficiently vibrating the container 2. Can be generated.

Form of implementation 3. In the third embodiment, manufacturing of the induction coil 6 of the induction heating cooker will be described.

FIG. 9 is a plan view of an induction coil of an induction heating cooker showing a third embodiment of the present invention, and FIG. 10 is an explanatory view of a method for processing this induction coil. The same or corresponding parts are designated by the same reference numerals.
The side induction coil 6a and the middle induction coil 6b are closely wound spirally.

Next, the production of the induction coil 6 will be described. First, the conductor wire is wound around a forming jig (not shown) having a constant interval corresponding to the diameter of the induction coil, and then the conductors are fixed by a heat-treatment applied fusion layer in advance around the conductor wire or bonded. Fix between the conductors using a chemical. Thus, as shown in FIG. 10A, the induction coil 6 that is easy to handle and does not cause loosening can be obtained.

Next, as shown in FIG. 10 (b), only the middle induction coil 6b is half-turned with respect to the paper surface and inverted. As a result, the middle induction coil 6b is wound in the opposite direction to the side induction coil 6a as shown in FIG. 10 (c), and the induction coil 6 is completed.

As described above, according to the third embodiment, the side induction coil 6a and the middle induction coil 6b are spirally closely wound, and the conductors are fixed by fusion or adhesion, and then the middle induction coil 6b. By reversing 6b, the induction coil 6 can be easily manufactured, and the finished dimensions are stable, which leads to stabilization of the heating state, and as a result, it is possible to improve the performance and quality at low cost. Become.

Fourth Embodiment In the third embodiment, 1
Although it has been described that the side induction coil 6a and the middle induction coil 6b are formed from one induction coil 6, in the fourth embodiment, the side induction coil 6a and the middle induction coil 6b are separately formed and both coils are connected. The manufacturing of the induction coil 6 will be described together.

FIG. 11 is a plan view of an induction coil of an induction heating cooker according to the fourth embodiment, and FIG. 12 is a plan view of another induction coil according to the fourth embodiment. In the figure, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals. Reference numeral 30 is a cylindrical metal and is a parallel connector for connecting a plurality of conductors, and 31a and 31b are round terminals attached by caulking to the ends of the conductors.

Next, connection of the side induction coil 6a and the middle induction coil 6b by the parallel connector 30 will be described with reference to FIG. First, a conductive wire is wound around a forming jig A (not shown) having a constant interval corresponding to the coil diameter of the side induction coil 6a, and a forming jig having a constant interval corresponding to the coil diameter of the middle induction coil 6b. B (not shown) is wrapped around a conductor, and the conductors are fixed by a fusion layer which is pre-applied around the conductors by heat treatment, or the conductors are fixed by using an adhesive. 6a and the middle induction coil 6b are manufactured separately.

After that, the middle induction coil 6b is arranged on the inner circumference of the side induction coil 6a, and both coils are wound in opposite directions, so that the inner circumference end of the side induction coil 6a and the middle induction coil 6a. The outer end of the coil 6b is inserted into the parallel connector 30 and connected by caulking to fix both coils. As a result, the induction coil 6 in which the side induction coil 6a and the middle induction coil 6b are wound in opposite directions is completed.

Next, connection of the side induction coil 6a and the middle induction coil 6b with the round terminals 31a and 31b will be described with reference to FIG. First, the forming jig A having a constant interval corresponding to the coil diameter of the side induction coil 6a.
The conductor wire is wound around the conductor wire, and the conductor wire is wound around the molding jig B having a constant interval corresponding to the coil diameter of the middle induction coil 6b, and the conductors are fixed by a fusion layer pre-applied around the conductor wire by heat treatment. Or using an adhesive to fix the conductors together, and further to round terminals 31a, 31b.
Are respectively attached to the inner peripheral end of the side induction coil 6a and the outer end of the middle induction coil, and the side induction coil 6a and the middle induction coil 6b are individually manufactured.

After that, the middle induction coil 6b is arranged on the inner circumference of the side induction coil 6a, and both coils are wound in opposite directions so that the inner circumference end of the side induction coil 6a has a round shape. Terminal 31a and round terminal 3 at the outer end of the middle induction coil
1b is connected with a screw (not shown) or an eyelet (not shown), etc., and both coils are fixed. As a result, the induction coil 6 in which the side induction coil 6a and the middle induction coil 6b are wound in opposite directions is completed.

As described above, according to the fourth embodiment, since the side induction coil 6a and the middle induction coil 6b can be manufactured separately, each induction coil has a simple winding shape and a complicated forming jig is used. It is not necessary to use it, the induction coil can be easily manufactured, and the finished dimensions are stable, which leads to stabilization of the heating state, and as a result, it is possible to improve performance and quality at low cost.

Embodiment 5. 13 is a block diagram of a control circuit of an induction heating cooker according to a fifth embodiment of the present invention,
FIG. 14 is a chart of the operation of this control circuit, showing the relationship between the gate input voltage of the switching element, the high-frequency current flowing in the switching element, and the collector voltage of the switching element in the induction heating cooker. FIG. 15 is a diagram showing the relationship between the vibration of the container and the frequency in this induction heating cooker. Note that FIG. 1 is used as a cross-sectional view of the induction heating cooker.

In the figure, the same or corresponding parts as those of the above-mentioned embodiment are designated by the same reference numerals and the description thereof will be omitted. 32
Is a frequency detecting means for measuring the number of times the drive circuit 28 is turned on or off and detecting the frequency of the high frequency current to the induction heating coil 6, and 34 is the frequency detected by the frequency detecting means 32 and the frequency storing means 33. It is a frequency comparing means for comparing the frequency with the selected frequency and outputting the comparison result.

Next, the operation will be described. First, an outline will be described. AC power from the commercial power supply 21 is rectified by the rectifier 22.
Then, the switching element 25 is turned on / off to apply a high-frequency current to the induction coil 6, and the magnetic field generated from the induction coil 6 heats the container 2. further,
The induction coil 6 includes a side induction coil 6a and a middle induction coil 6
Since b is wound in the opposite direction, the magnetic field and force generated by energizing both coils are in opposite directions.

Next, the operation of inputting a high frequency current flowing through the induction coil 6 and varying the frequency will be described. 14
In the above, the magnitude relationship of the ON period T1 of the switching element 25 is (a) <(b), and as shown in the figure, by increasing the ON period T1 of the switching element 25,
Since the high frequency current flowing through the switching element 25 increases, the input to the container 2 increases and the frequency of the high frequency current decreases. That is, by changing the ON time T1 of the switching element 25, the input to the container 2 and the frequency can be changed.

Since FIG. 13 shows a one-stone resonance circuit,
After turning off the switching element 25, the collector voltage VC
When the switching element 25 is turned on in the state where E is generated and the collector voltage VCE is high, the loss that is the product of the voltage and the current increases and heat is generated, so that the switching element 25 becomes sufficiently low after the collector voltage VCE of the switching element 25 becomes low. Need to turn on. Therefore, the VCE zero-cross detection circuit 26 detects the time when the collector voltage VCE becomes low, and the control means 27 sends the ON signal of the switching element 25 to the drive circuit 28 based on the detection signal.

Here, during the period in which the collector voltage VCE becomes sufficiently low after the switching element 25 is turned off, the container 2
Since it varies depending on the shape, material, etc. of the switching element 25, it is not possible to calculate the ON / OFF cycle of the switching element 25 based on the ON period T1 of the switching element 25. Therefore, the frequency detecting means 32 counts the number of times the drive circuit 28 is turned on for a predetermined time, and detects the frequency of the high frequency current based on this number. For example, the frequency is detected by detecting the number of times of ON or OFF for 20 msec or both times and calculating the detection result (for example, 50 times in this case).

Therefore, the frequency comparison means 34 and the frequency detected by the frequency detection means 32 and the frequency storage means 3 are included.
The frequencies stored in advance in 3 are compared, and the comparison result is output to the control means 27. The control means 27 uses the signal from the frequency comparison means 34 to switch the switching element 25 when the frequency of the high frequency current is lower than the stored frequency.
The ON period T1 of the switching element 25 is increased, while the ON period T1 of the switching element 25 is increased when the frequency of the high frequency current is higher than the stored frequency. This allows
The frequency of the high-frequency current is changed so as to be a predetermined frequency stored in the frequency storage means 33 and input to the induction heating coil 6, and the container 2 is induction-heated by the magnetic field generated from the induction heating coil 6.

Next, the operation of vibrating the container 2 at a high frequency by driving the induction heating coil 6 with a high frequency current having a predetermined frequency will be described. For example, in FIG. 15, the magnitude of the vibration generated in the container 2 is measured using the vibration sensor, and it can be understood that the vibration is large at an integral multiple of about 11 kHz, and the natural vibration of the container 2 It turns out that the frequency is 11 kHz, which means that container 2 has 1
It can be said that vibration of an integral multiple of 1 kHz is likely to occur. It is also known that resonance occurs at a common multiple of the natural vibration frequency of the resonating object.

For example, the natural vibration frequency of the container 2 is 11 kHz.
z, the frequency of the high frequency current of the induction coil 6 is 29.3k.
In the case of Hz, the generated vibration is 8 times 11 kHz, 29.
It becomes 88 kHz, which is three times 3 kHz. That is, the control means 27 can efficiently generate vibration by setting the frequency of the high frequency current flowing through the induction heating coil 6 to be an integral multiple of the natural vibration frequency of the container 2.

In this case, since the container 2 vibrates if it is an integral multiple of 11 kHz, for example, in order to obtain a vibration of 88 kHz of 8 times, 88 kHz (1
/ 1), 44 kHz (1/2), 29.3 kHz (1 /
3), by adjusting the ON period of the switching element 25 by setting a frequency stored in advance in the frequency storage means 33 so that a high frequency current of 22 kHz (1/4) or the like flows, the container 2 can be efficiently used. Can be vibrated.

As described above, according to the fifth embodiment, the current in the opposite direction is passed through the side induction coil 6a and the middle induction coil 6b of the induction coil 6, and the current passing through the induction coil 6 is vibrated in the container. Since the frequency is efficiently generated, it is possible to stably generate high-frequency vibration having a large vibration in the container 2 and promote water absorption of the food to be cooked.

In the fifth embodiment, the frequency detecting means 32 detects the frequency by counting the number of times the drive circuit 7 is turned on, but the VCE zero-cross detecting circuit 16
The frequency can be detected also by the high frequency current detected by the current detection means (not shown).

The frequency detecting method by the frequency detecting means 14 may detect the number of times of ON and / or the number of times of OFF for one second and output the detection result directly as a method other than the above. Further, in the above description, the frequency itself is matched, but the frequency detecting means 14 detects the number of times of ON for 20 msec, stores the number of times of ON of the desired frequency for 20 msec in the frequency storing means 8, and detects the frequency. The number of times of on detected by the means 14 may be made to coincide with the number of times of on of the frequency storage means 8, and the same action and effect can be obtained.

In the above embodiments, the number of induction coils used is 2 to 4. However, the number of induction coils is not limited to this, and a plurality of induction coils can be used to achieve the same effect as above. It goes without saying that the effect can be obtained. Although the embodiment in which a plurality of spiral induction coils are connected in series has been mainly described, even if a high frequency current is supplied by parallelly connecting one of the plurality of induction coils with another induction coil in reverse winding. The same effect can be obtained.
Furthermore, assuming that the winding directions of multiple induction coils are the same,
The control circuit can obtain the same effect even if the high frequency current supply direction of one of them is reversed.

[0059]

As described above, according to the present invention, a container of magnetic material for containing food and a plurality of spiral-shaped containers which are provided so as to face the outer circumference of the container and inductively heat the container by energization. Of the induction coil and control means for controlling current supply to the plurality of induction coils, and the direction of the high frequency current flowing through at least one induction coil among the plurality of induction coils is high frequency flowing through another induction coil. By energizing in the opposite direction to the direction of the current and vibrating the container at high frequency,
High-frequency vibration can be easily applied to the object to be heated in the container, which improves water absorption efficiency and heating efficiency.

Also, a magnetic container for storing the food,
A plurality of spiral induction coils, which are provided so as to face the outer circumference of the container, at least one induction coil is wound in a direction opposite to that of the induction coil, and induction heats the container by energization, and the plurality of induction coils. And a control means for controlling current supply to the induction coil, and a high-frequency current is passed in the spiral direction of the plurality of induction coils to vibrate the container at a high frequency, so that the object to be heated in the container can be easily subjected to the high-frequency vibration. As a result, the water absorption efficiency is improved and the heating efficiency is also improved.

Further, since the plurality of induction coils are electrically connected in series, it is possible to easily apply high frequency vibration to the object to be heated in the container, which improves water absorption efficiency and heating efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view of an induction heating cooker showing a first embodiment of the present invention.

FIG. 2 is a plan view of an induction coil in the induction heating cooker according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a control circuit in the induction heating cooker according to the first embodiment of the present invention.

FIG. 4 is a chart of the operation of the control circuit in the induction heating cooker according to the first embodiment of the present invention.

FIG. 5 is a plan view of another induction coil in the induction heating cooker according to the first embodiment of the present invention.

FIG. 6 is a plan view of another induction coil in the induction heating cooker according to the first embodiment of the present invention.

FIG. 7 is a sectional view of an induction heating cooker showing a second embodiment of the present invention.

FIG. 8 is a perspective view of an induction coil in an induction heating cooker showing a second embodiment of the present invention.

FIG. 9 is a plan view of an induction coil in an induction heating cooker showing a third embodiment of the present invention.

FIG. 10 is an explanatory diagram of a method for processing an induction coil in the induction heating cooker according to the third embodiment of the present invention.

FIG. 11 is a plan view of an induction coil in an induction heating cooker showing a fourth embodiment of the present invention.

FIG. 12 is a plan view of another induction coil in the induction heating cooker according to the fourth embodiment of the present invention.

FIG. 13 is a block diagram of a control circuit in an induction heating cooker showing a fifth embodiment of the present invention.

FIG. 14 is a chart of the operation of the control circuit in the induction heating cooker showing the fifth embodiment of the present invention.

FIG. 15 is a diagram showing a relationship between vibration and frequency of a container in the induction heating cooker according to the fifth embodiment of the present invention. ．

FIG. 16 is a sectional view of a conventional induction heating cooker.

FIG. 17 is a sectional view of a conventional induction heating cooker.

[Explanation of symbols]

2 container, 6 induction coil, 6a side induction coil, 6b middle induction coil, 6c first induction coil, 6d second induction coil, 6e third induction coil, 6e right induction coil, 6f right winding induction coil, 6g left winding induction Coil, 6h Right-handed induction coil, 6i Left-handed induction coil, 27 Control means, 30 Parallel connector, 31 Round terminal.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Sunaga             1728 Omaeda, Hanazono-cho, Osato-gun, Saitama 1728               Within Mitsubishi Electric Home Equipment Co., Ltd. (72) Inventor Akira Inokuma             1728 Omaeda, Hanazono-cho, Osato-gun, Saitama 1728               Within Mitsubishi Electric Home Equipment Co., Ltd. F term (reference) 3K051 AA08 AC40 AD03 AD07 CD01                       CD42                 3K059 AA08 AC40 AD03 AD07 CD00                       CD72                 4B055 AA03 AA09 BA21 BA22 CA71                       CB02 CB27 DA02 DB14 GC40

Claims (3)

[Claims] 1. A magnetic material container for storing food, a plurality of spiral induction coils which are provided so as to face the outer periphery of the container and which induction heat the container by energization, and to the plurality of induction coils. Controlling means for controlling the current supply of the induction coil, the direction of the high-frequency current flowing through at least one induction coil among the plurality of induction coils is opposite to the direction of the high-frequency current flowing through the other induction coil, and An induction heating cooker characterized by vibrating a container at high frequency. 2. A container made of a magnetic material for containing food to be cooked, and provided so as to face the outer periphery of the container. At least one induction coil is wound in a direction opposite to that of the induction coil, and the container is induced by energization. A plurality of spiral induction coils to be heated and a control means for controlling current supply to the plurality of induction coils are provided, and high-frequency current is passed in the spiral direction of the plurality of induction coils to vibrate the container at high frequencies. An induction heating cooker characterized by the following. 3. The induction heating cooker according to claim 1, wherein the plurality of induction coils are electrically connected in series.