JP4942522B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker in which an induction heating coil is disposed below a top plate on which a cooking container is placed and heated.

In an electromagnetic cooker that places a cooking container on a top plate and arranges an induction heating coil below the top plate and heats the cooking container with this induction heating coil, for example, as shown in Patent Document 1 In addition, the output current detection transformer 13 and the input current detector 19 compare the input current of the inverter circuit with the coil current of the heating coil 9, and when the pan material is not suitable for induction heating or when there is no load. Is configured to stop energization of the heating coil.
Japanese Patent Publication No. 60-4559

  Moreover, in the said induction heating apparatus, as shown also in patent document 1, by energizing a heating coil intermittently at the time of a heating start etc. and comparing an input electric current and a coil electric current, the material of a pot and the pot Although the presence or absence is judged, when small metals, such as a spoon and a fork, are put on a top plate, these small metals are heated by energization for the above-mentioned pan judgment, and there is a problem that danger is high.

  Furthermore, when the pan is determined, the heating coil is energized for a short time of 1 second or less, and this is performed at intervals of several seconds. However, depending on the material of the pan and the arrangement of the pan, it can be heated but takes time to determine In this case, there is a problem that it takes time to start heating.

  Then, this invention aims at determining the presence or absence of a cooking container efficiently.

According to a first aspect of the present invention, there is provided a top plate for placing the cooking container, an induction heating coil disposed below the top plate, a thermal power setting means for setting the thermal power of the induction heating coil, and the induction An input current detecting means for detecting an input current of an inverter circuit for supplying a high frequency current to the heating coil, a coil current detecting means for detecting a current flowing through the induction heating coil, the induction based on the output of the heating power setting means, etc. A control means for controlling energization to the heating coil, wherein the light emitting element is disposed below the top plate and emits infrared rays toward the top plate, and the light receiving element receives the infrared rays reflected by the cooking container. The first pan detecting means for detecting the presence or absence of the cooking container from the output of the light receiving element, the input current detected by the input current detecting means, and the coil current by the coil current detecting means A second pan detecting means for detecting the presence / absence of the cooking container in comparison, and the second pan detecting means is configured to detect the presence / absence of the cooking container at a predetermined interval set in advance. When the first pot detecting means detects the cooking container, the second pot detecting means detects the presence or absence of the cooking container at the time of detection.

  According to the configuration of the first aspect of the present invention, the presence or absence of the cooking container above the induction heating coil of the top plate is detected quickly and reliably by the pan detecting means configured by the light receiving and emitting elements. The installation at the position can be detected, and the second pan detecting means is configured to detect the presence / absence of the cooking container at a predetermined interval, and the first pan detecting means is configured to detect the cooking container. When detected, the detection time of the cooking container by the second pot detection means is shortened by performing detection by the second pot detection means at this detection time point, and the time required for determining the presence or absence of the cooking container is shortened. Is something you can do.

  An embodiment according to the present invention will be described with reference to FIG. 1. Reference numeral 1 denotes a cooker body of an electromagnetic cooker that is used by being incorporated into a system kitchen or the like by a drop-in method, and a top plate 2 made of heat-resistant glass is provided on the top surface. A pair of left and right induction heating coils 3 and 4 and a radiant heater 5 serving as heat sources for the left and right stoves are housed inside the top plate.

  On the other hand, an operation panel 6 is disposed on the right side of the front surface of the electromagnetic cooker body 1, and a grill door 8 for the grill 7 is disposed on the left side of the operation panel so that it can be pulled out. Includes a seesaw-type power switch 9, a plurality of operation keys 10, and a plurality of operation knobs 11 that perform a push-push rotation operation. The operation knobs 11... Are pulled out by a push operation and rotated to start energizing the induction heating coils 3 and 4 and the radiant heater 5. Then, the heating power, cooking time, cooking temperature, etc. are set, the left induction heating coil 11 is operated with the left operation knob 11, the radiant heater 5 is operated with the central operation knob 11, and the right operation is operated. The right induction heating coil 4 is operated by the knob 11.

  Further, the outer peripheral edge of the top plate 2 is pressed and fixed by the top plate frame 12, and a non-contact type touch key for detecting an input operation from a change in capacitance is provided at the front end portion of the top plate frame. The constructed top surface operation unit 13 is disposed, and intake and exhaust holes 14 and 14 are opened on the left and right of the rear end of the top plate frame 12.

  On the other hand, as shown in FIG. 2, the top panel operation unit 13 has a fire key 16 on the front or back surface of the glass plate 15, hot water keys 17 and 17 for automatic water cooking, and a fried food key 18 for frying food. , 18 and the like are arranged by printing, and an input operation to each of these touch keys is detected by an operation circuit board (not shown) arranged on the back surface of the glass plate 15, and the touch operation is performed on the operation circuit board. An input operation is detected by a change in capacitance due to contact or proximity of a finger or the like to the area.

  Furthermore, a liquid crystal display 19 composed of a liquid crystal display with a backlight or the like is disposed below the front portion of the top plate 2 between the induction heating coils 3 and 4. The cooking time and cooking temperature are displayed.

  FIG. 3 shows a part of a circuit block diagram of a control circuit 30 serving as a control means for controlling energization to the induction heating coils 3, 4 and the like. A power supply circuit is connected to a commercial 200 V power supply 31 via a relay contact 32. 33, and a main control circuit 34 constituted by a microcomputer is connected to the output of the power supply circuit, and a voltage detection circuit 35 is connected to the power supply 31 via the power switch 9. The output of the circuit is connected to the input port of the main control circuit 34, and the operation keys 10... Arranged on the operation panel 6 are connected to the input port via the key detection circuit 43.

  An inverter circuit 37 is connected to the relay contact 32 via an input current detection circuit 36, and the induction heating coils 3 and 4 and the current value supplied to the coil are detected at the output of the inverter circuit. A coil current detection circuit 38 is connected, and the coil current detection circuit and the output of the input current detection circuit 36 are connected to the input port of the main control circuit 34.

  The output port of the main control circuit 34 is connected to the radiant heater 5 and the upper and lower grill heaters 45, 45 disposed in the grill 7 via a heater drive circuit 44, and via a cooling fan drive circuit 46. A cooling fan 47 mounted in the cooker body 1 is connected, and a relay drive circuit 48 for operating the relay contact 32 is connected.

  Further, an LED lamp 50... For displaying an ON / OFF operation state of the operation keys 10... Arranged on the operation panel 6 is connected to the output port of the main control circuit 34 through the LED drive circuit 49. ing.

  Further, the input / output port of the main control circuit 34 is connected to a memory 53 and a communication circuit 54 constituted by a non-volatile memory for storing various data, and the communication circuit is connected to a sub-control constituted by a microcomputer. The circuit 60 is connected.

  As shown in FIG. 4, the input port of the sub-control circuit 60 includes pan bottom temperature sensors 62 and 62 disposed near the center of the induction heating coils 3 and 4 via the temperature detection circuit 61, and an induction heating coil. The coil temperature sensors 63 and 63 are connected to the induction heating coils so as to detect the temperature of the induction heating coils. The operation unit 13 is connected to the input / output port via the key detection microcomputer 66. Are connected to a hot water key 16, a water heater key 17, a deep-fried food key 18, and the like, and an input operation by these keys is detected by a change in capacitance due to the approach of a finger to these keys.

  Further, as shown in FIG. 4, at a substantially central position of the induction heating coils 3 and 4, a light emitting element 70 that emits infrared rays toward the top plate 2, and infrared rays emitted from the light emitting elements are A light receiving element 71 that receives the reflected light that has passed through the plate 2 and reflected on the bottom surface of the cooking container 22 and again passed through the top plate 2 is disposed, and the output of this light receiving element is input to the pan detection circuit 72. In addition, by inputting the output of the pan detection circuit to the input port of the sub-control circuit 60, it is determined whether or not the cooking container 22 is placed at a predetermined position on the top plate 2 from the output of the pan detection circuit 72. These constitute the first pan detecting means.

  In the above embodiment, the energization to the light receiving element 71 is controlled via the pan detection circuit 72. However, the energization may be performed directly by the output of the main control circuit 34 or the sub control circuit 60. The light emitting / receiving elements 71 and 70 may be energized only for a predetermined period of time, or may be energized at predetermined intervals during cooking, or may be configured to be energized at all times during cooking.

  Further, the main control circuit 34 compares the input current and the coil current of the inverter circuit 37 from the outputs of the input current detection circuit 36 and the coil current detection circuit 38, and the presence or absence of the cooking container 22 and the cooking container Second pot detecting means 73 for determining whether or not a material suitable for induction heating is provided.

  Thus, the operation when cooking using the induction heating coils 3 and 4 will be described. After the cooking container 26 such as a pan is placed above the induction heating coils 3 and 4 of the top plate 2 (FIG. 4), the power switch 9 is turned on, and then the knob 11 of the operation panel 6 is pushed and pulled out to rotate, or the heating power is set with the heating key 16. This operation is detected by the main control circuit 34 and the sub-control circuit 60, energization of the induction heating coil 4 is started, and cooking is started.

  On the other hand, in the first embodiment of the present invention, the main control circuit 34 and the sub control circuit 60 simultaneously start the energization of the induction heating coils 3 and 4, and as shown in FIG. From the output of the pan detecting circuit 72 constituting the pan detecting means, it is detected whether or not the cooking container 22 is placed at a predetermined position on the top plate 2, and if it is determined that there is T, the induction heating coils 3 and 4 Heating is started by supplying a current corresponding to the set thermal power.

  Thereby, the presence or absence of the cooking container 22 can be detected quickly and reliably with a relatively simple configuration using the light emitting / receiving elements 71 and 70.

  In the second embodiment according to the present invention, the presence or absence of the cooking container 22 is detected by both the first pot detecting means and the second pot detecting means 73. With these configurations, the cooking container is more reliably provided. The presence or absence of 22 can be detected.

  FIG. 6 is a timing chart showing a third embodiment according to the present invention. In the second embodiment, even if the second pan detecting means 73 determines that the cooking container 22 is present at T, for example, When the pan detecting means cannot detect the presence of the cooking container 22, the energization to the induction heating coils 3 and 4 is stopped. When placed on the induction heating coil 3, the energization to the induction heating coils 3 and 4 can be stopped, and thereby malfunction due to erroneous detection can be surely prevented.

  FIG. 7 is a timing chart showing a fourth embodiment according to the present invention, wherein the second pan detecting means 73 applies a small amount of current preset at a predetermined interval T1 (for example, 5 seconds) to the induction heating coil 3. , 4 and comparing the coil current at that time with a predetermined value set in advance, the presence / absence of the cooking container 22 is determined, and the first pan detection means determines that the cooking container 22 is present at T. Then, the pot detection by the second pot detecting means 73 is executed at this T, and when it is determined that the second pot detecting means also has the cooking container 22 at this time, the induction heating coils 3 and 4 are energized. It is configured to start.

  With these configurations, the presence or absence of the cooking container 22 can be determined quickly and reliably in a short time regardless of the detection interval set in the second pan detection means 73.

  FIG. 8 is a timing chart showing a fifth embodiment according to the present invention. In the second embodiment or the fourth embodiment, even when the first pot detecting means cannot detect the presence of the cooking container 22. For example, when the second pan detecting means 73 determines that the cooking container 22 is present at T, the energization to the induction heating coils 3 and 4 is started.

  When the bottom of the cooking container 22 is greatly curved or the bottom of the cooking container 22 is formed of a rough surface with low light reflectance, the first pot detecting means cannot detect the cooking container 22 due to these configurations. However, when the second pan detecting means 73 detects the cooking container 22, the heating can be started so that the presence or absence of the cooking container can be determined relatively quickly without requiring a long time for the pot determination. Is.

  In each said Example, the detection interval of the cooking container by a 2nd pan detection means and the input electric current at the time of pan detection are not limited to these, What is necessary is just to set suitably.

  In addition, the arrangement and configuration of the light receiving and emitting elements 71 and 70 constituting the first pan detecting means are not limited to the above embodiment, and the presence or absence of the cooking container is determined by the light reflected on the bottom surface of the cooking container 22. Anything that can be detected is acceptable.

It is a perspective view which shows the Example of this invention. It is a top view of the principal part similarly. It is a block diagram of a control means similarly. It is a side longitudinal cross-sectional view which similarly shows the Example of the principal part. It is a timing chart which similarly shows an operation example. It is a timing chart which similarly shows the operation example in another Example. It is a timing chart which similarly shows the operation example in another Example. It is a timing chart which similarly shows the operation example in another Example.

Explanation of symbols

2 Top plate 3 Induction heating coil 4 Induction heating coil 6 Operation panel (thermal power setting means)
13 Operation part (thermal power setting means)
22 Cooking container 30 Control circuit (control means)
36 Input current detection circuit (input current detection means)
37 Inverter circuit 38 Coil current detecting means 70 Light emitting element 71 Light receiving element 73 Second pan detecting means

Claims (1)

A top plate on which the cooking container is placed, an induction heating coil disposed below the top plate, thermal power setting means for setting the thermal power of the induction heating coil, and an inverter circuit for supplying a high frequency current to the induction heating coil Input current detecting means for detecting the input current of the coil, coil current detecting means for detecting the current flowing through the induction heating coil, and control means for controlling the energization to the induction heating coil based on the output of the heating power setting means A light emitting element that is disposed below the top plate and emits infrared rays toward the top plate, a light receiving element that receives the infrared light reflected by the cooking container, and an output of the light receiving element from the cooking container. The first pot detecting means for detecting the presence or absence of the cooking current, the input current detected by the input current detecting means and the coil current detected by the coil current detecting means are compared to determine whether the cooking container is present. A second pan detection means for detecting a provided, with constructed as to detect the presence or absence of the cooking vessel at a predetermined interval set in advance the second pan detection means, said control means, said first pan An induction heating cooker characterized in that when the detection means detects a cooking container, the second pot detection means detects the presence or absence of the cooking container at the time of detection .

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