JP2005011670A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker which prevents response failure in temperature detecting of a temperature sensor during energization to an induction heating coil. <P>SOLUTION: When a heating level is 'high' in turning a power switch on, and the temperature detected by a thermistor 7 is lower than a specified temperature (50°C), a controller 8 controls the amount (heating power level) of current supply to an induction heating coil 5 to be decreased to an 'intermediate' level until the temperature detected by the thermistor 7 reaches to the specified temperature (50°C). This prevents response failure in temperature of a pan 6 detected by the thermistor 7 during the passing of the current to the induction coil 5, and can control accidental rapid temperature rise of the pan 6, which a user does not intend to happen. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating cooker such as an induction heating type cooker or a rice cooker.
[0002]
[Prior art]
An induction heating cooker or the like using an induction heating system includes an induction heating coil on the lower side of a glass plate made of a non-conductive member on which a cooking utensil such as a magnetic pot is placed, and the induction heating coil has a high-frequency current. Can be cooked by generating a high frequency magnetic field in the induction heating coil and directly heating a cooking utensil (such as a pan) on the glass plate by this high frequency magnetic field.
[0003]
In the induction heating cooker using the induction heating method described above, a temperature sensor that detects the temperature of the cooking utensil is installed on the lower surface of the glass plate, and this temperature sensor detects the temperature of the cooking utensil during cooking through the glass plate. The temperature is controlled during cooking.
[0004]
At this time, if the heating power is strong when the power is turned on, the cooking utensils (such as pans) on the glass plate are immediately heated by induction heating and the temperature rises rapidly, but the temperature sensor cooks through the glass plate. By detecting the temperature of the utensil (pan etc.), the temperature detection is slow to follow at the initial stage, and appropriate temperature control may be delayed when the cooking utensil (pan etc.) rises above a predetermined temperature.
[0005]
For this reason, in order to improve the follow-up of temperature detection by the temperature sensor when the power is turned on, for example, a temperature sensor (temperature detection element) is placed in a metal cap made of a material such as magnetic ferrite having a Curie temperature. An induction heating cooker has been proposed (see, for example, Patent Document 1).
[0006]
In Patent Document 1, when the power is turned on, in addition to heat conduction from the glass plate, the cap itself is heated by the passage of magnetic flux until the cap reaches the Curie temperature, so that the temperature sensor (temperature detection element) is effective. To heat up.
[0007]
[Patent Document 1]
Japanese Utility Model Publication No. 6-151049
[Problems to be solved by the invention]
However, in the configuration in which the cap itself generates heat and the temperature sensor (temperature detection element) is heated as in Patent Document 1, the configuration is complicated because the temperature sensor is heated by a cap that is another heating source. At the same time, the temperature sensor temperature rise does not correspond to the temperature rise of the cooking utensil, so when the temperature rise of the temperature sensor is larger, the thermal power is weakened, and the cooking utensil lacks the heating power. there were.
[0009]
Then, an object of this invention is to provide the induction heating cooking appliance which can prevent the excessive temperature rise of a cooking appliance, without the lack of heating power occurring at the time of power activation.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention according to claim 1 is provided with an induction heating coil that generates a high-frequency magnetic field by energizing a high-frequency current under the plate-like non-conductive member, and the induction heating coil has a high-frequency current. In the induction heating cooker that heats the cooking utensil placed on the non-conductive member by energizing the electromagnetic wave, the cooking that is heated by electromagnetic induction in contact with or close to the lower surface of the non-conductive member Temperature detecting means for detecting the temperature of the appliance via the non-conductive member; control means for controlling energization of the induction heating coil based on temperature information detected by the temperature detecting means; and the cooking by electromagnetic induction An energization level adjustment switch for adjusting the magnitude of energization to the induction heating coil when heating the appliance, and an energization switch for turning on / off the energization to the induction heating coil. When the energization switch is turned on and the temperature detected by the temperature detecting means is lower than a predetermined temperature, the induction heating is controlled by the control means until the temperature detected by the temperature detecting means reaches the predetermined temperature. It is characterized in that the magnitude of energization to the coil is lowered to a predetermined level.
[0011]
According to a second aspect of the present invention, an induction heating coil that generates a high-frequency magnetic field by energization of a high-frequency current is provided below the plate-like non-conductive member, and the induction heating coil is energized with the high-frequency current. In an induction heating cooker that heats a cooking utensil placed on a non-conductive member by electromagnetic induction, the temperature of the cooking utensil heated by electromagnetic induction is brought into contact with or close to the lower surface of the non-conductive member. When heating the cooking utensil by electromagnetic induction, temperature detecting means for detecting through a non-conductive member, control means for controlling energization to the induction heating coil based on temperature information detected by the temperature detecting means, An energization level adjustment switch for adjusting the magnitude of energization to the induction heating coil, and an energization switch for turning on / off energization to the induction heating coil, and the energization switch When the temperature is detected and the temperature detected by the temperature detecting means is lower than a predetermined temperature, the magnitude of the energization to the induction heating coil is set to a predetermined level by the control of the control means until a predetermined time elapses. It is characterized by lowering.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
[0013]
<Embodiment 1>
1 is a schematic perspective view showing an induction heating cooker according to Embodiment 1 of the present invention, and FIG. 2 is a schematic sectional view showing the induction heating cooker according to Embodiment 1 of the present invention.
[0014]
In the induction heating cooker (IH cooking heater) 1 according to the present embodiment, a glass plate 3 as a non-conductive member is installed on the upper surface of the cooker body 2, and an operation panel is provided on the front side of the cooker body 2. 4 is installed. An induction heating coil 5 is installed on the lower surface of the glass plate 3 in a non-contact manner, and the pan 6 serving as a magnetic cooking utensil placed on the glass plate 3 is heated by electromagnetic induction heating (Induction Heating). be able to. In addition, the induction heating cooker 1 of FIG. 1 is provided with two-ring-shaped heating surfaces 3a and 3b on the surface of the glass plate 3, and the induction heating coil is positioned below the heating surfaces 3a and 3b. 5 is installed.
[0015]
A thermistor 7 as a temperature sensor is installed on the lower surface of the glass plate 3 so as to be in contact with the glass plate 3, and detects the temperature of the pan 6 during cooking through the glass plate 3.
[0016]
A control device (CPU) 8 is connected to the operation panel 4 and the thermistor 7, and the control device (CPU) 8 is connected to the drive circuit 9 based on thermal power adjustment information input from the operation panel 4 by a user's operation. A control signal is output to control energization of a high-frequency current to the induction heating coil 5, and temperature control is performed on the pan 6 based on temperature information input from the thermistor 7. In this temperature control, when the pan 6 is kept at a predetermined temperature, or when the pan 6 rises to a predetermined temperature or higher, energization of the high-frequency current to the induction heating coil 5 is stopped to prevent overheating.
[0017]
As shown in FIG. 3, the operation panel 4 has been described in conjunction with the pressing operation of the heating power adjustment switches 4a and 4b and the heating power adjustment switches 4a and 4b for adjusting the energization level of the high-frequency current applied to the induction heating coil 5. Display lamps 4c, 4d, power switch 4e, and induction heating coil 5 (heating surface 3a) on the right side that turn on and display the thermal power level corresponding to the energization level (seven levels from “weak” to “strong” in the present embodiment). An energization switch 4f to the left induction heating coil 5 (heating surface 3b) is provided.
[0018]
The thermal power adjustment can be performed by pressing the thermal power adjustment switches 4a and 4b. When the right arrow portion is pressed, energization to the induction heating coil 5 is increased and the thermal power is increased, and when the left arrow portion is pressed, the induction heating coil 5 is pressed. The energization to can be reduced and the thermal power can be lowered.
[0019]
The display lamps 4c and 4d have seven display lamps arranged in one row by dividing the power level between “low” to “medium” to “strong” into seven levels in the present embodiment, and the thermal power adjustment switch 4a. Alternatively, the position of the thermal power level set by the pressing operation 4b is lit up.
[0020]
Further, in the cooker body 2, the induction heating coil 5, the control device 8, the drive circuit 9 for the induction heating coil 5, and the cooling fan (not shown) for cooling the induction heating coil 5, the drive circuit 9 and the like are provided. Etc. are provided.
[0021]
Next, the heating operation of the induction heating cooker 1 according to the above-described embodiment will be described.
[0022]
First, when the user turns on the power switch 4e of the operation panel 4 and turns on the energization switch 4f to the induction heating coil 5 (heating surface 3a) on the right side, for example, the drive circuit is driven by the control signal from the control device 8. A high-frequency current is applied from 9 to the induction heating coil 5 on the heating surface 3a side. When the induction heating coil 5 is energized with a high frequency current, an eddy current flows in the pan 6 due to the generation of a high frequency magnetic field in the magnetic pan 6 by electromagnetic induction, and the pan 6 is heated by Joule heat due to this eddy current, Cooking can be done.
[0023]
At this time, the user adjusts the thermal power with the thermal power adjustment switch 4a or 4b in accordance with cooking by the pan 6 (fried food, boiled food, etc.).
[0024]
By the way, when the user turns on the power switch 4e of the operation panel 4 of the induction heating cooker 1 and turns on the energization switch 4f to the right induction heating coil 5 (heating surface 3a), for example, When the heating power adjustment switch 4a is operated and the heating power level remains "strong", or when a strong heating power is desired immediately, for example, an energization switch to the right induction heating coil 5 (heating surface 3a) When the thermal power adjustment switch 4a is operated immediately after turning on 4f to set the thermal power level to "strong", the pan 6 on the glass plate 3 is immediately heated by induction heating and the temperature rises rapidly.
[0025]
Moreover, in the induction heating cooking appliance 1 of this Embodiment, when the energization switch 4f is turned ON, it can also set so that a thermal power level may become "strong" automatically.
[0026]
Hereinafter, control of the thermal power level when the thermal power level is set to “strong” from the start of energization in the present embodiment will be described with reference to the flowchart shown in FIG. 4.
[0027]
As described above, when the thermal power level is “strong”, the temperature of the pan 6 is rapidly increased by induction heating immediately after the energization switch 4f is turned on, so that the thermistor 7 at room temperature has a thermal conductivity. By detecting the temperature of the pan 6 through the bad glass plate 3, the follow-up of the temperature detection is delayed and the pan 6 may overheat.
[0028]
Therefore, in the embodiment of the present invention, for example, when the energization switch 4f to the induction heating coil 5 (heating surface 3a) on the right side is turned on as described above, the operation of the heating power adjustment switch 4a during the previous use is performed. If the thermal power level remains “strong” or immediately after the energization switch 4f to the induction heating coil 5 (heating surface 3a) is turned on, the thermal power adjustment switch 4a is operated to set the thermal power level to “strong”. When set (step S1), the control device 8 determines whether or not the detected temperature of the thermistor 7 is equal to or higher than a predetermined temperature (50 ° C. in the present embodiment) based on the detected temperature information input from the thermistor 7. (Step S2).
[0029]
In addition, in step S2, although the detection temperature of the thermistor 7 to be determined is 50 ° C., the detection temperature is not limited to this temperature. For example, the detection temperature may be set between about 40 ° C. and 70 ° C.
[0030]
If the detected temperature of the thermistor 7 is 50 ° C. or lower in step S2, the power to the induction heating coil 5 is lowered by the control of the controller 8 at the same time as the energization switch 4f is turned on, and the heating power level is “medium”. (Step S3) so that the temperature of the pan 6 does not rise suddenly. At this time, the “strong” position of the display lamp 4c is blinked to notify the user that the firepower level is suppressed to “medium”.
[0031]
When the control device 8 detects that the detected temperature of the thermistor 7 has risen to 50 ° C. or more based on the detected temperature information input from the thermistor 7 during heating at the thermal power level “medium”. (Step S4), energization corresponding to the initially set thermal power level “strong” is performed (step S5), and the pan 6 is heated and cooked at the thermal power level “strong”.
[0032]
Further, in step S4, heating is performed at the heating power level “medium” until the temperature detected by the thermistor 7 reaches 50 ° C. (the time between them is about 1 minute). In step S1, if the thermal power level is not set to “strong” from the beginning, energization is performed according to the set thermal power level (step S6), and the pan 6 is heated and cooked at the set thermal power level. I do.
[0033]
Thus, when the thermal power level is “strong” at the start of cooking, the thermal power level is automatically lowered to “medium” until the detected temperature of the thermistor 7 becomes 50 ° C. or higher under the control of the control device 8. By this, the sudden temperature rise of the careless pan 6 unintended by the user can be suppressed.
[0034]
<Embodiment 2>
The induction heating cooker in the present embodiment is the same as the induction heating cooker in the first embodiment shown in FIGS. 1 to 3 except for the control of the thermal power level when the thermal power level is set to “strong” from the start of energization. This is the same, and a duplicate description is omitted.
[0035]
Hereinafter, control of the thermal power level when the thermal power level is set to “strong” from the start of energization in the present embodiment will be described with reference to the flowchart shown in FIG.
[0036]
As described above, when the thermal power level is “strong”, the temperature of the pan 6 is rapidly increased by induction heating immediately after the energization switch 4f is turned on, so that the thermistor 7 at room temperature has a thermal conductivity. By detecting the temperature of the pan 6 through the bad glass plate 3, the follow-up of the temperature detection is delayed and the pan 6 may overheat.
[0037]
Therefore, in the embodiment of the present invention, when the user turns on, for example, the energization switch 4f of the operation panel 4 of the induction heating cooker 1 as described above, the operation of the heating power adjustment switch 4a during the previous use is performed. When the thermal power level remains “strong” or when the thermal power adjustment switch 4a is operated immediately after the energization switch 4f is turned on to set the thermal power level to “strong” (step S11), the control device 8 determines whether the detected temperature of the thermistor 7 is equal to or higher than a predetermined temperature (50 ° C. in the present embodiment) based on the detected temperature information input from the thermistor 7 (step S12).
[0038]
In step S12, the detected temperature of the thermistor 7 to be determined is 50 ° C., but the temperature is not limited to this temperature. For example, the detected temperature may be set between about 40 ° C. and 70 ° C.
[0039]
In step S12, if the detected temperature of the thermistor 7 is 50 ° C. or less, a timer is started simultaneously with the ON of the energizing switch 4f as shown in FIG. 6 (step S13). The energization to the induction heating coil 5 is lowered and set to a heating power weakened to a heating power level “middle” (step S14). At this time, the “strong” position of the display lamp 4c is blinked to notify the user that the firepower level is suppressed to “medium”.
[0040]
When t1 elapses after the energization switch 4f is turned on (1 minute in the present embodiment) (step S15), it is estimated that the temperature detected by the thermistor 7 has reached a predetermined temperature (about 50 ° C.) or more. Therefore, energization according to the initially set thermal power level “strong” is performed (step S16), and the pan 6 is heated and cooked at the thermal power level “strong”. In step S11, if the thermal power level is not set to “strong” from the beginning, energization is performed according to the set thermal power level (step S17), and the pan 6 is heated and cooked at the set thermal power level. I do.
[0041]
Thus, if the thermal power level is “strong” when the energization switch 4f (or 4g) is turned on, the thermal power level is automatically set to “medium” for a predetermined time (this implementation) by the control of the control device 8. In this mode, the temperature of the pan 6 that is not intended by the user can be prevented from suddenly rising.
[0042]
In the present embodiment, the time during which the thermal power level is lowered from “strong” to “medium” after turning on the energizing switch 4f is 1 minute. However, the present invention is not limited to this. It can be set to an arbitrary time (several tens of seconds to 2 or 3 minutes) according to the output of 1 or the type of cooking utensil such as the pan 6.
[0043]
In the first and second embodiments described above, the thermal power level is lowered from “strong” to “medium” after the energization switch 4f is turned on, but it is lowered to a thermal power level between “strong” and “weak”. You may do it. Note that when the heating power level is “medium” to “weak”, the heating power at the start of heating is weak, and the temperature rise of the pan 6 is too gradual, so that the usability is deteriorated.
[0044]
In the first and second embodiments described above, the operation panel 4 is an example of the induction heating cooker 1 having the press-type heating power adjustment switches 4a and 4b. However, when the heating power adjustment switch is turned to the left or right, for example. The present invention can be similarly applied to an induction heating cooker that is a dial-type knob for adjusting the thermal power level.
[0045]
<Embodiment 3>
In the second embodiment, when the thermal power level is “strong” when the energizing switch 4f (or 4g) is turned on, the thermal power level is automatically set to “medium” from the beginning by the control of the control device 8. In the present embodiment, the heating power level becomes “strong” when the energization switch 4f (or 4g) is turned on as shown in FIG. If it is, the control unit 8 automatically reduces the thermal power level from “strong” to “medium” linearly for a predetermined time t1 (for example, about 45 seconds), and then returns the thermal power level to “strong”. I did it.
[0046]
Also in the present embodiment, an abrupt temperature rise of the careless pan 6 not intended by the user can be suppressed.
[0047]
In the control pattern from “strong” to “medium” of the thermal power level in the present embodiment shown in FIG. 7, the thermal power level from “strong” to “medium” in the second embodiment shown in FIG. Compared to the control pattern, the amount of heating in the predetermined time t1 is large, so the time required to lower the thermal power level can be shortened.
[0048]
<Embodiment 4>
In the present embodiment, as shown in FIG. 8, when the thermal power level is “strong” when the energization switch 4 f (or 4 g) is turned on, the thermal power level “ The level was lowered from “strong” to “medium” in a stepped manner for a predetermined time t1 (for example, about 45 seconds), and then the heating power level was returned to “strong”.
[0049]
Also in the present embodiment, an abrupt temperature rise of the careless pan 6 not intended by the user can be suppressed.
[0050]
In the control pattern from “strong” to “medium” of the thermal power level in the present embodiment shown in FIG. 8, the thermal power level from “strong” to “medium” in the second embodiment shown in FIG. Compared to the control pattern, the amount of heating in the predetermined time t1 is large, so the time required to lower the thermal power level can be shortened.
[0051]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the temperature detected by the temperature detecting means is lower than the predetermined temperature when the energization switch is turned on, the temperature detected by the temperature detecting means reaches the predetermined temperature. During this period, the degree of energization to the induction heating coil is reduced to a predetermined level by the control of the control means, thereby preventing the temperature sensing followability of the cooking utensil of the temperature sensing means when energizing the induction heating coil from being deteriorated. Therefore, it is possible to suppress a sudden temperature rise of an inadvertent cooking utensil unintended by the user.
[0052]
According to the second aspect of the present invention, when the temperature detected by the temperature detecting means is lower than the predetermined temperature when the energization switch is turned on, the induction heating is controlled by the control of the control means until the predetermined time elapses. By lowering the magnitude of energization to the coil to a predetermined level, it is possible to prevent the temperature detection followability of the cooking device of the temperature detection means during energization to the induction heating coil from being unintended by the user. An abrupt temperature rise of an inadvertent cooking utensil can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic external view showing an induction heating cooker according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing the induction heating cooker according to Embodiment 1 of the present invention.
FIG. 3 is a diagram showing an operation panel of the induction heating cooker according to the first embodiment of the present invention.
FIG. 4 is a flowchart for explaining control of a thermal power level in the first embodiment of the present invention.
FIG. 5 is a flowchart for explaining control of a thermal power level in the second embodiment of the present invention.
FIG. 6 is a view showing a control pattern of a thermal power level in the second embodiment of the present invention.
FIG. 7 is a diagram showing a thermal power level control pattern in Embodiment 3 of the present invention.
FIG. 8 is a diagram showing a thermal power level control pattern according to the fourth embodiment of the present invention.
[Explanation of symbols]
1 induction heating cooker 2 cooker body 3 glass plate (non-conductive member)
4 Operation panel 4a, 4b Thermal power adjustment switch (energization level adjustment switch)
4c, 4d indicator lamp 4e power switch 4f, 4g energizing switch 5 induction heating coil 6 pan (cooking utensil)
7 Thermistor (temperature detection means)
8 Control device (control means)

Claims (2)

A cooking utensil provided with an induction heating coil that generates a high-frequency magnetic field when energized with a high-frequency current is provided below the plate-like non-conductive member, and placed on the non-conductive member by energizing the induction heating coil with the high-frequency current In induction heating cooker that heats by electromagnetic induction,
Temperature detecting means for detecting the temperature of the cooking utensil that is in contact with or close to the lower surface of the nonconductive member and is heated by electromagnetic induction via the nonconductive member;
Control means for controlling energization to the induction heating coil based on temperature information detected by the temperature detection means;
An energization level adjustment switch for adjusting the magnitude of energization to the induction heating coil when heating the cooking utensil by electromagnetic induction;
An energization switch for turning on / off energization of the induction heating coil,
When the energization switch is turned on and the temperature detected by the temperature detecting means is lower than a predetermined temperature, the induction heating is controlled by the control means until the temperature detected by the temperature detecting means reaches the predetermined temperature. Reduce the magnitude of energization to the coil to a predetermined level,
An induction heating cooker characterized by that. A cooking utensil provided with an induction heating coil that generates a high-frequency magnetic field when energized with a high-frequency current is provided below the plate-like non-conductive member, and placed on the non-conductive member by energizing the induction heating coil with the high-frequency current In induction heating cooker that heats by electromagnetic induction,
Temperature detecting means for detecting the temperature of the cooking utensil that is in contact with or close to the lower surface of the nonconductive member and is heated by electromagnetic induction via the nonconductive member;
Control means for controlling energization to the induction heating coil based on temperature information detected by the temperature detection means;
An energization level adjustment switch for adjusting the magnitude of energization to the induction heating coil when heating the cooking utensil by electromagnetic induction;
An energization switch for turning on / off energization of the induction heating coil,
When the energization switch is turned on and the temperature detected by the temperature detection means is lower than a predetermined temperature, the magnitude of the energization to the induction heating coil is controlled by the control of the control means until a predetermined time elapses. Down to a certain level,
An induction heating cooker characterized by that.

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