JPH08322717A - Rice-cooker by composite heating - Google Patents

Abstract

PURPOSE: To use a rice-cooker by composite heating even at an ordinary home within a range of allowable electric current and to safely use it without a pot. CONSTITUTION: An electric source 1 in the single direction, an inverter circuit 4, a heating coil 9, a magnetron 15, a voltage elevating transformer 11 and a load switching circuit 20 are provided and the load switching circuit 20 is constituted of a relay 21 with a IC contact point structure and a relay driving circuit 23 and an NC terminal 24 is connected to the heating coil 9 and an NC terminal 25 is connected to the primary coil of the voltage elevating transformer 11 and in addition, a relay coil 26 is connected to the relay driving circuit 23 through a microswitch 22 interlocking with the existence of a pot of a rice-cooker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite heating rice cooker using an induction heating system and an induction heating system.

[0002]

2. Description of the Related Art In recent years, in order to improve the taste of electric rice cookers, an induction heating method using an inverter, which is expected to produce a strong fire, is taking the lead in place of the conventional sheath heater method. In addition, microwave ovens using inverters have also advanced into the field of rice cookers by cooling and reheating rice.

[0003]

However, when the induction heating type rice cooker is equipped with the dielectric heating type microwave oven function, the current capacity (about 2
There is a problem that it is an indispensable condition to avoid simultaneous energization of both systems due to the restriction of about 0 ampere). Furthermore, if the magnetron is accidentally driven without a pan, there is a risk of radio wave leakage when unnecessary radio waves are emitted in the device.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a composite heating rice cooker that can be used in a general household within an allowable current range and can be safely used even without a pot. is there.

[0005]

In order to achieve the above object, the present invention has a unidirectional power source obtained by rectifying a commercial power source, a smoothing circuit, a resonance capacitor and a switching element. An inverter circuit for converting to electric power, a heating coil for receiving the output of the inverter circuit, a magnetron for generating microwaves, a primary winding for receiving the output of the inverter circuit, and a secondary high-voltage winding for generating high-voltage power to the magnetron. Line and a step-up transformer having a heater winding for supplying electric power to the cathode of the magnetron, and load switching for switching and connecting the output of the inverter circuit to either the heating coil or the primary winding of the step-up transformer. And a load switching circuit is configured by a relay having a 1C contact structure and a relay drive circuit. The normally closed (hereinafter referred to as NC) heating coil terminal, the normally open (hereinafter N
The terminal (referred to as O) is connected to the primary winding of the step-up transformer, and the relay coil is further connected to the relay drive circuit through a micro switch that is interlocked with the presence or absence of the inner pot of the rice cooker.

[0006]

According to the present invention, the output of the inverter circuit is switched and connected to either the heating coil or the primary winding of the step-up transformer by the load switching circuit in the above-described structure, so that simultaneous energization to both systems is avoided. It is a translation. Further, when there is no pot, the electricity is supplied to the relay coil by the action of the micro switch, and even if the control state is the magnetron drive state, the relay contact is connected to the heating coil side connected to the NC terminal.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 (a) shows an electric circuit diagram of a composite heating rice cooker according to an embodiment of the present invention, in which 1 is a unidirectional power source, a commercial power source 2 and a rectifying bridge 3, and 4 is an inverter circuit. In addition, a smoothing circuit 5 for preventing power line noise due to switching, a resonance capacitor 6a, a resonance capacitor 6b, and a switching element 7 are provided. 8 is a drive circuit for controlling the switching element 7, 9 is a heating coil connected in parallel with the resonance capacitor 6a for receiving the output of the inverter circuit 4, and 10 is connected in parallel with the resonance capacitor 6b for receiving the output of the inverter circuit 4. The primary winding of the step-up transformer 11, 12 is the secondary high-voltage winding of the step-up transformer 11, which includes the high-voltage capacitor 13 and the high-voltage diode 14a,
It is connected between the anode 16 and the cathode 17 of the magnetron 15 via the high voltage diode 14b. A heater winding 18 is connected to the cathode 17 via a choke coil 19. Reference numeral 20 is a load switching circuit for switching and connecting the output of the inverter circuit 4 to either the heating coil 9 or the primary winding 10 of the step-up transformer 11.

FIG. 1 (b) shows an electric circuit diagram of the load switching circuit 20. A relay 21 having a 1C contact structure and a micro switch 2 which is interlocked with the presence or absence of an inner pot (not shown) of the rice cooker.
2 and the relay drive circuit 23 constitute the load switching circuit 20. The NC terminal 24 of the relay 21 is connected to the heating coil 9, the NO terminal 25 is connected to the primary winding 10 of the step-up transformer, and the relay coil 26 is connected to the relay drive circuit 23 via the microswitch 22.

Next, the operation and action of this structure will be described. In FIG. 1A, first, the operation by the induction heating method will be described. The output of the inverter circuit 4 is connected to the heating coil 9 by the load switching circuit 20,
When a drive signal is applied to the drive circuit 8, the commercial power supply 2 and the unidirectional power supply 1 formed by the rectifying bridge 3 pass through the smoothing circuit 5 to the resonance capacitor 6 a and the switching element 7.
Is converted into high-frequency power by the inverter circuit 4 consisting of, and high-frequency current is supplied to the heating coil 9. Then, the inner pot (not shown) of the rice cooker whose surface is made of a magnetic material is heated by the principle of induction heating, and the rice is cooked according to the program incorporated in the microcomputer.

The case of driving the dielectric heating type magnetron 15 will be described. When the output of the inverter circuit 4 is connected to the primary winding 10 of the step-up transformer 11 by the load switching circuit 20, the output of the secondary high-voltage winding 12 of the step-up transformer 11 is the output of the high-voltage capacitor 13 and the high-voltage diode 1.
4a, high-voltage diode 14b rectifies the voltage and applies a high voltage of about 4 kV to magnetron 15. Also,
When the heater winding 18 supplies a proper heater current to the cathode 17 of the magnetron 15 through the choke coil 19, the magnetron 15 generates microwaves, and the microwaves are radiated from the upper part of the inner pot to the rice during the rice cooking process. By doing so, it is possible to realize cooked rice with further improved taste.

Now, the operation of the load switching circuit 20 will be described in detail with reference to FIG. Micro switch 2
2 is closed with the inner pot of the rice cooker set,
When the inner pot is taken out, it is configured to be in an open state, and the series circuit of the micro switch 22 and the relay coil 26 is further connected as a load of the relay drive circuit 23. In this state, when the inner pot of the rice cooker is set, the micro switch 22 is closed, and when an exciting current is applied to the relay coil 26 by the relay drive circuit 23, the relay contact is the NC of the heating coil 9 side. The connection is switched from the contact 24 to the NO contact 25 side of the primary winding 10 side of the step-up transformer 11, and when the inverter circuit 4 shown in FIG. 1A is operated, the magnetron 15 is driven to enter the microwave irradiation state. If there is no inner pot, relay drive circuit 2
Since the micro switch 22 is in the open state even when trying to operate 3, the relay contact is not switched, and even when the inverter circuit 4 is operated, only the high frequency current is supplied to the heating coil 9, and the magnetron 15 is unnecessary. The danger of irradiating such radio waves can be avoided and it can be used safely.

[0013]

As is apparent from the above description, the present invention has the following effects.

That is, since the output of the inverter circuit is switched and connected to either the heating coil or the primary winding of the step-up transformer by the load switching circuit, simultaneous energization to both types is avoided, and even in a general household an allowable current range is provided. It is possible to provide a compound heating rice cooker that can be used inside. Furthermore, when there is no pan, the electricity is supplied to the relay coil by the action of the micro switch, and even if the control state is the magnetron drive state, the relay contact is the NC terminal. It is possible to avoid the risk of the magnetron irradiating unnecessary radio waves when it is connected to the heating coil side that is connected to, and it is possible to provide a combined heating rice cooker that can be used safely even without a pot.

[Brief description of drawings]

FIG. 1 (a) is an electric circuit diagram of a composite heating rice cooker according to one embodiment of the present invention, and FIG. 1 (b) is an electric circuit diagram of a load switching circuit thereof.

[Explanation of symbols]

 1 Unidirectional Power Source 2 Commercial Power Source 4 Inverter Circuit 5 Smoothing Circuit 6a, 6b Resonant Capacitor 7 Switching Element 9 Heating Coil 10 Primary Winding 11 Booster Transformer 12 Secondary High Voltage Winding 15 Magnetron 17 Cathode 18 Heater Winding 20 Load Switching Circuit 21 Relay 22 Micro switch 23 Relay drive circuit 24 NC terminal 25 NO terminal 26 Relay coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsunori Tanie 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Shinichiro Sumiyoshi, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A unidirectional power supply obtained by rectifying a commercial power supply, an inverter circuit having a smoothing circuit, a resonance capacitor and a switching element for converting the unidirectional power supply into high frequency power, and an output of the inverter circuit. A heating coil, a magnetron that generates microwaves, a primary winding that receives the output of the inverter circuit, a secondary high voltage winding that generates high voltage power to the magnetron, and a heater winding that supplies power to the cathode of the magnetron. And a load switching circuit for switching and connecting the output of the inverter circuit to either the heating coil or the primary winding of the step-up transformer, and the load switching circuit is a relay having a 1C contact structure. And a relay drive circuit, and the normally closed terminal is used as the heating coil. A compound heating rice cooker in which the open terminal is connected to the primary winding of the step-up transformer, and the relay coil is connected to the relay drive circuit via a micro switch that works with the presence or absence of the inner pot of the rice cooker.