JPH0471320B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to an induction heating cooker.

Structure of the conventional example and its problems Due to its principle, the conventional induction heating cooker can only heat pots made of magnetic metal.

In ordinary households, there are many non-metallic pots such as aluminum pots and clay pots, but these pots have the inconvenience of not being able to heat up. On the other hand, for earthenware pots, etc., there is an idea to embed a metal that can be heated by induction in the earthenware pot, but this means that you will end up purchasing a new earthenware pot specifically for this cooker, and you will not be able to use your existing earthenware pot. Another disadvantage is that you cannot use other items you already have, such as aluminum pots or heat-resistant glass. In addition, as shown in Japanese Utility Model Application Publication No. 55-124796, there is also a cooking device that is equipped with a heating coil and a heater so that the clay pot can be heated on the heater side. It is necessary to provide a separate heating area with a heater next to the
The increasing size of cookers has become a problem.

Purpose of the Invention The present invention aims to heat all types of pots, including non-metallic pots such as clay pots and metal pots such as hollow pots, without increasing the size of the cooker, and to improve the usability of the heating process. purpose.

Structure of the Invention In order to achieve the above object, the present invention includes a heating coil, a plate disposed above the heating coil, an object to be heated such as a pot placed on the plate, and a heating coil. a high-frequency power conversion device that generates magnetic lines of force to inductively heat the heated body;
A heating element such as a heater that heats the object to be heated on the heating coil, a heated object detection means for detecting whether or not the object to be heated is made of a material that can be heated by induction, and an object to be heated by the heated object detection means. It is equipped with a switch that energizes the high-frequency power converter when it detects that the object to be heated is a material that can be heated by induction, and energizes the heating element when it detects that the object to be heated is a material that cannot be heated by induction.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows an embodiment of the structure of the present invention, in which a pot 1 as an object to be heated is placed on a top plate 2. In FIG. The heating element 3 is arranged under the top plate 2, and a voltage is applied to the heating element 3 through electrode plates 5, 5'. This electrode plate 5, 5'
is fixed to the coil base 4 and in pressure contact with the heating element 3, and is connected to a power supply section through voltage supply sections 8 and 8'. A heating coil 6 that generates lines of magnetic force so as to generate eddy currents in the pot is fixed to the coil base 4, and lead parts 7 and 7' are connected to the output part of a coil excitation power source, for example, a high frequency power conversion circuit 9.

Next, a schematic circuit configuration will be explained with reference to FIG.

The power from the power plug 12 is switched to the heating element 3 side or the high frequency power conversion circuit 9 side by a switch 10, and the switching of this switch 10 will be explained later in the explanation based on FIG. 2. First, switch 1
As can be seen from the figure, when 0 is turned on to the b side, voltage is applied to the heating element 3 via the voltage supply parts 8 and 8',
The temperature of the top plate 2 is raised. switch 1
When 0 is set to the a side, the high frequency power conversion circuit 9 converts the commercial frequency to approximately 30 KHz, and high frequency current is supplied to the heating coil 6 via the lead parts 7 and 7', and the pot 1 is heated by induction with the generated magnetic lines of force. .

The heating element 3 is formed of, for example, a coating of graphite or an oxidized pot, and the lines of magnetic force pass through the heating element 3 and are absorbed by the pot.

As mentioned above, switching between resistance heating by the heating element 3 and induction heating by the high frequency power conversion circuit 9 is performed by the second
As shown in the figure, electricity is automatically switched to the high frequency power converter or the heating element depending on whether the heated object is made of a material that can be heated by induction.

That is, the pot 1 is placed on the top plate 2. This pot is made of magnetic metal such as iron enamel, cast iron,
Induction heating is possible if the pot is made of 18 chrome stainless steel or the like, but in this case, the magnet 13 is attracted to the pot 1, so the magnet 13 moves upward. Therefore, the contact of the micro switch 14 is opened, and the relay 15 opens the contact of the switch 10.
The high-frequency power conversion circuit 9 operates to excite the heating coil 6, thereby inducing an eddy current in the pot 1 and heating it.

On the other hand, if the pot is an aluminum pot, earthenware pot, heat-resistant glass pot, etc., the magnet 13 will not stick to it and the contact of the micro switch 14 will remain pressed due to its own weight, so the relay 15 will switch the contact of the switch 10 to the b side. Therefore, the heating element 3 is energized to raise the top plate 2 to a high temperature, thereby heating the pot 1.

Even if there is no pot 1, resistance heating is performed by the heating element 3 in the same way as described above, so a switch 16 for turning off the power is additionally required in this case.

As described above, the pot detection device (heated object detection means) composed of the magnet 13, the micro switch 14, etc. is provided, and resistance heating and induction heating can be automatically discriminated and selected.

FIG. 3 is a plan view of FIG. 1 showing the arrangement relationship between the heating element 3 and the heating coil 6.

FIG. 4 shows another example of arrangement in which the heating element 3 is arranged in the center of the top plate 2.

FIG. 5 shows a heating element 3 on the upper side of the top plate 2.
This is another embodiment in which the heat conduction to the pot by the heating element is improved.

Figure 6 shows a spiral heating element 3 and a heating coil 6.
This figure shows another embodiment in which the elements are arranged alternately.

Effects of the Invention As described above, according to the present invention, the object to be heated on the heating coil can be heated with a heating element, so a pot made of any material can be heated with either induction heating or heating with a heating element, and unlike the conventional method. There is no need to provide a heating area for the heating element separate from the heating area for the heating coil, and the size of the cooking appliance can be reduced. Moreover, since the switch changes the energization to the high frequency power converter or the heating element according to the material of the heated object, it can be used without worrying about the material, and the usability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment showing the configuration of the present invention, FIG. 2 is a diagram showing an embodiment of the same circuit configuration, and FIG. 4 is a sectional view of another embodiment showing the location of the heating element, FIG. 5 is a sectional view of still another embodiment showing the location of the heating element, and FIG. FIG. 7 is a sectional view of a main part showing another embodiment. 1... Pot, 2... Top plate, 3... Heating element, 9... High frequency power conversion circuit, 13... Magnet, 14... Micro switch, 15... Relay.

Claims (1)

[Claims] 1. A heating coil, a plate disposed above the heating coil, an object to be heated such as a pot placed on the plate, and a device that generates magnetic lines of force in the heating coil to induce the object to be heated. A high-frequency power converter for heating, a heating element such as a heater for heating a heated object on the heating coil, a heated object detection means for detecting whether the heated object is made of a material that can be heated by induction, and An induction heating cooker equipped with a switch that energizes a high-frequency power converter when a heating element detection means detects that the object to be heated is made of a material that can be heated by induction, and energizes the heating element when it detects that the object to be heated is a material that cannot be heated by induction. .