JP6029012B2 - Induction heating rice cooker - Google Patents

Description

  The present invention relates to an induction heating rice cooker that heats a pot and a lid by induction heating.

  In rice cookers, the water vapor in the pan at the end of cooking or at the time of heat condensation condenses on the lid part or the side part of the pan, and the water drops drop on the rice, causing the problem of whitening of the rice and the rice becoming sticky. is there. In order to solve such a problem, in a conventional rice cooker, a configuration including a lid heating means for heating the lid portion and a side surface heating means for heating the side surface portion of the pan has been proposed (for example, Patent Document 1).

  In the rice cooker configured as described above, the lid heating means and the side surface heating means use a method in which the side portions of the lid and the pan are induction heated by the magnetic field generated from the heating coil, that is, in the rice cooker A lid heating coil for induction heating the lid, a side heating coil for induction heating the side surface of the pan, and an inverter circuit for supplying a high frequency current to the lid heating coil and the side heating coil (for example, Patent Document 2).

Japanese Patent Publication No. 8-13289 Japanese Patent Laid-Open No. 5-261010

  In the conventional rice cooker configured as described above, the high-frequency current input to the lid heating coil and the side heating coil is controlled in order to prevent condensation on the side of the lid and pan at the end of rice cooking and when keeping warm. And it is necessary to hold | maintain the side part of a lid | cover or a pan at predetermined temperature. In particular, when using the rice cooker in an environment where the power supply voltage is different, it is necessary to change the characteristics of the heating coil. For example, in the configuration of the conventional rice cooker as described above, a lid heating coil that heats the lid when the voltage of the AC power supply is in a 100V system region and a 200V system region, and a side surface heating that heats the side surface of the pan It was necessary to greatly change the inductance value of the coil.

  For example, when an input power of 100 V and 200 W is supplied from an AC power source to an inverter that supplies a high-frequency current to the series circuit of the lid heating coil and the side heating coil, an input of 200 V and 200 W is input to the same series circuit. The current flowing through the series circuit of the lid heating coil and the side surface heating coil is different from that when power is supplied from an AC power source. Experimentally, when 200V input power is supplied from an AC power supply, the value of current flowing through the series circuit of the lid heating coil and the side heating coil is compared to when 100V input power is supplied from the AC power supply. Is known to be slightly smaller. As the input voltage to the inverter increases, the frequency of the heating coil increases, the inductance value of the heating coil decreases, and the resistance of the heating coil increases. As a result, the current value flowing through the heating coil is reduced. Thus, when the inductance value (L) of the heating coil decreases and the current value (I) flowing through the heating coil decreases, the resonance voltage (V) of the capacitor connected in parallel or in series with the heating coil decreases.

  This can be easily estimated by the following equation (1) used in a general resonance circuit. In equation (1), the capacitance (C) of the capacitor connected in parallel or in series with the heating coil is constant.

1 / 2LI ² = 1 / 2CV ² (1)

L: Inductance value of heating coil I: Current value of heating coil C: Capacitance of capacitor connected in parallel or series to heating coil V: Resonance voltage; Voltage across capacitor connected in parallel or series to heating coil

  In the case of supplying 200V power to the inverter, if the same circuit configuration (resonance voltage is 100V) as in the case of supplying 100V power, a high turn-on voltage is generated when the switching elements constituting the inverter are turned on. However, there has been a problem that the loss at the turn-on of the switching element increases as the noise terminal voltage increases.

  In order to solve this problem, conventionally, a method of increasing the number of turns of the heating coil and increasing the inductance value of the heating coil has been adopted.

  However, it is extremely difficult to make the heating ratio (ratio of wattage [W]) of the lid heating coil and the side surface heating coil the same between the 100V specification rice cooker and the 200V specification rice cooker. Increasing the number of turns widens the entire heating coil and changes the heating distribution itself.

  In the 100V specification and the 200V specification, if the width of the entire heating coil is the same, the thickness of the heating coil increases, and the lid and the casing used in the 100V specification may not be used in the 200V specification. Moreover, it is possible to make the coil wire itself of the heating coil thin so that the lid heating coil and the side heating coil have the same heating ratio, but since the number of turns is different, even if the region where heating concentrates is the same There is a problem that the degree of concentration of magnetic flux is different and the heating distribution is slightly different. Therefore, it is difficult to make the 100V specification rice cooker and the 200V specification rice cooker correspond to each other with the same configuration.

  As mentioned above, at the end of rice cooking or when keeping warm, the lid heats the lid so that moisture does not condense on the sides of the lid or pan and the dew drops on the rice to cause whitening or stickiness It corresponds by adjusting the heating ratio of the heating coil and the side heating coil that heats the side part of the pan, but the lid heating coil and the side heating coil adjusted with a 100V specification rice cooker are used as a 200V specification rice cooker. Has a problem that the inductance value when operating the inverter circuit is not sufficient, and the heating ratio cannot be adjusted with high accuracy and cannot be used. Moreover, in the rice cooker of 200V specification, compared with the rice cooker of 100V specification, it was necessary to increase the number of turns of a heating coil, and had the subject that the rice cooker itself had to be structurally enlarged. .

  Moreover, in the rice cooker of 200V specification, when the number of turns of the lid heating coil and the side heating coil is increased, the heating distribution changes from the case of the rice cooker of 100V specification, and the lid heating coil from the design stage. And there was a need to adjust the side heating coil.

  The present invention solves the problems in the conventional rice cooker, and even when used in an area where the power supply voltage is different, without changing the heating ratio of the lid heating coil and the side heating coil, It aims at providing the induction heating type rice cooker which can change easily the inductance value of the series circuit which has a side surface heating coil.

The induction heating rice cooker of the present invention is
A rice cooker body that is supplied with power from an AC power source and performs rice cooking operation;
A pot housed inside the rice cooker body;
A bottom heating coil for induction heating the bottom of the pan;
A bottom inverter circuit for supplying a high-frequency current to the bottom heating coil;
A lid that opens and closes the pan;
A lid heating coil for inductively heating the lid;
A side heating coil for induction heating the side of the pan;
A lid / side inverter circuit for supplying a high-frequency current to the lid heating coil and the side heating coil;
A control circuit that controls the bottom surface inverter circuit and the lid / side surface inverter circuit to supply a high-frequency current to the bottom surface heating coil, the lid heating coil, and the side surface heating coil according to a rice cooking operation; ,
The lid heating coil and the side surface heating coil are connected in series, and an auxiliary coil can be connected in series with respect to the series circuit of the lid heating coil and the side surface heating coil. The auxiliary coil can be connected to and separated from the power supply voltage. In the induction heating rice cooker configured as described above, for example, the number of turns of the lid heating coil and the number of turns of the side surface heating coil even in regions where the power supply voltage is greatly different, such as the 100V region and the 200V region. It is possible to easily make the heating ratio of the lid and the side portion of the pan the same without increasing the amount easily. In addition, in the induction heating type rice cooker of the present invention, an auxiliary coil that does not contribute to heating can be connected in series to the series circuit of the lid heating coil and the side surface heating coil. The inductance value is reduced by removing the coil, and an auxiliary coil is attached to increase the inductance value when the power supply voltage is 200V.

  The present invention is an induction that can easily change the inductance value of a series circuit having a lid heating coil and a side surface heating coil without changing the heating ratio of the lid heating coil and the side surface heating coil even in specifications with different power supply voltages. It aims at providing a heating type rice cooker.

The longitudinal cross-sectional view which shows the induction heating type rice cooker of Embodiment 1 which concerns on this invention. Electric circuit diagram in case of 200V specification in induction heating type rice cooker of embodiment 1 Electrical circuit diagram in case of 100V specification in induction heating type rice cooker of embodiment 1 The block diagram of the auxiliary coil in the induction heating type rice cooker of Embodiment 1 The block diagram of another auxiliary coil in the induction heating type rice cooker of Embodiment 1.

The induction heating rice cooker according to the first aspect of the present invention is
A rice cooker body that is supplied with power from an AC power source and performs rice cooking operation;
A pot housed inside the rice cooker body;
A bottom heating coil for induction heating the bottom of the pan;
A bottom inverter circuit for supplying a high-frequency current to the bottom heating coil;
A lid that opens and closes the pan;
A lid heating coil for inductively heating the lid;
A side heating coil for induction heating the side of the pan;
A lid / side inverter circuit for supplying a high-frequency current to the lid heating coil and the side heating coil;
A control circuit that controls the bottom surface inverter circuit and the lid / side surface inverter circuit to supply a high-frequency current to the bottom surface heating coil, the lid heating coil, and the side surface heating coil according to a rice cooking operation; ,
The lid heating coil and the side surface heating coil are connected in series, and an auxiliary coil can be connected in series with respect to the series circuit of the lid heating coil and the side surface heating coil. The auxiliary coil can be connected to and separated from the power supply voltage. The induction heating rice cooker according to the first aspect of the present invention configured as described above has a lid heating coil and a side surface without changing the heating ratio of the lid heating coil and the side surface heating coil, even in specifications with different power supply voltages. The inductance value of the series circuit having the heating coil can be easily changed.

  In the induction heating type rice cooker of the second aspect of the present invention, in the first aspect, the auxiliary coil is composed of a single coil different from the lid heating coil and the side surface heating coil, The auxiliary coil is removed when the power supply voltage of the AC power supply is the first voltage system, and the auxiliary coil is attached when the power supply voltage of the AC power supply is the second voltage system. The induction heating rice cooker of the 2nd aspect comprised in this way is comprised so that the auxiliary | assistant coil which does not contribute to the heating of a rice cooker can be contacted / separated, for example, a power supply voltage is a 100V system as a 1st voltage system In the region, the auxiliary coil is not used, and in the 200V region where the power supply voltage is the second voltage system, it is possible to increase the inductance value by connecting the auxiliary coil in series to the series circuit of the lid heating coil and the side heating coil. . For this reason, in the induction heating type rice cooker of the second aspect, the heating ratio between the lid heating coil and the side surface heating coil is changed to the power source without changing the inductance values of the lid heating coil and the side surface heating coil and the shape of the heating coil. It can be the same in regions with different voltages.

  An induction heating rice cooker according to a third aspect of the present invention is the series circuit of the lid heating coil, the side surface heating coil, and the auxiliary coil in the first aspect or the second aspect, wherein the auxiliary coil is the Compared to the lid heating coil, it is connected to a circuit electrically separated from the AC power supply side. The induction heating rice cooker of the 3rd aspect comprised in this way is comprised so that an auxiliary | assistant coil may be connected to the circuit separated from AC power supply compared with the lid heating coil, and a lid heating coil and a side heating coil It is possible to prevent the resonance voltage from increasing. Moreover, the voltage of the lid heating coil can be lowered, the insulation distance from other members in the wiring from the lid heating coil can be shortened, and the hinge portion between the rice cooker body and the lid is heated by the lid. Since the lead wire of the coil passes, the insulation distance of the lead wire of the lid heating coil can be kept short inside the hinge portion, and the rice cooker can be made compact.

  In the induction heating rice cooker according to the fourth aspect of the present invention, the auxiliary coil according to any one of the first aspect to the third aspect includes a rod-shaped ferrite, the lid heating coil, or the side surface heating coil. It is configured by winding a wire equivalent to the lead wire. In the induction heating type rice cooker of the 4th aspect comprised in this way, the auxiliary | assistant coil which can increase an inductance value can be easily processed with a compact structure, and the mounting inside a rice cooker is easy. Become. Moreover, since the said auxiliary | assistant coil can be manufactured together at the time of manufacture of a lid | cover heating coil or a side surface heating coil, manufacture as a rice cooker becomes easy. In addition, the auxiliary coil configured as described above uses a rod-shaped ferrite, so that it is less likely to saturate than a closed magnetic circuit ferrite, and the inductance value is less likely to fluctuate even with a large current. Can do.

The induction heating type rice cooker of the 5th aspect in this invention has the loop-shaped reflective frame comprised with the metal material in the outer periphery of the said bottom face heating coil in the aspect in any one of the said 1st aspect to the 4th aspect. And the auxiliary coil is arranged on the outer peripheral side of the reflection frame. In the induction heating type rice cooker of the 5th aspect comprised in this way, it becomes a structure which does not give the influence of the magnetic flux which leaks from an auxiliary coil with respect to a pan or a lid | cover.

  Hereinafter, an induction heating type rice cooker as an embodiment according to the present invention will be described with reference to the accompanying drawings. In addition, the induction heating type rice cooker of this invention is not limited to the structure described in the following embodiment, It is comprised based on the technical idea equivalent to the technical idea demonstrated in the following embodiment. Including an induction heating device.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view showing the induction heating rice cooker according to the first embodiment of the present invention.
As shown in FIG. 1, the rice cooker main body 1 is provided with a pan storage portion 3 capable of detachably storing a pan 2 for putting rice and water therein. A bottom heating coil 4 wound in a spiral shape is disposed on the outer surface of the bottom of the pan storage unit 3 so as to face the bottom of the pan 2, and a magnetic field generated from the bottom heating coil 4 causes the pan storage unit 3 to It is comprised so that the bottom part of the accommodated pot 2 may be induction-heated. Further, a side heating coil 5 wound in a cylindrical shape is disposed so as to face the side surface of the pan 2, and is configured to induction-heat the side surface of the pan 2 by a magnetic field generated from the side heating coil 5. Yes. The side heating coil 5 is often wound about 10 turns, and is set to have an inductance value of about 20 μH when the pan 2 is placed.

  An outer lid 6, which is a lid that can be opened and closed, is provided at the top opening of the rice cooker body 1 so that the pan 2 can be attached to and detached from the pan storage portion 3. The outer lid 6 that is a lid is provided so as to be rotatable with respect to the rice cooker main body 1 via a hinge portion, and the outer lid 6 is biased in the opening direction. Further, the outer lid 6 is configured to engage with the rice cooker body 1 so that the outer lid 6 can close the upper surface opening of the rice cooker body 1.

  In the outer lid 6, a detachable lid heating unit 7 is attached to a surface corresponding to the pan 2 stored in the pan storage unit 3. A lid heating coil 8 wound in a spiral shape is provided inside the outer lid 6 so as to face the lid heating unit 7, and the lid heating unit 7 is induction-heated by a magnetic field generated in the lid heating coil 8. It is configured to be.

  Generally, the lid heating coil has a large change in inductance value depending on its shape, and the number of turns of the lid heating coil is set between about 10 to 20 turns depending on the shape of the lid. Therefore, the inductance value of the lid heating coil varies depending on the number of turns. In the induction heating type rice cooker of the first embodiment, the inductance value of the lid heating coil 8 is about 20 μH to 30 μH with the lid heating unit 7 disposed.

  In addition, in the induction heating type rice cooker of Embodiment 1, the positional relationship between the side heating coil 5 and the lid heating coil 8 is such that when the rice cooker is viewed from vertically above, the winding center portion of the side heating coil 5 and the lid heating. The winding center part of the coil 8 is disposed so as to be substantially at the same position. That is, the center of winding of the side surface heating coil 5 and the center of winding of the lid heating coil 8 are substantially on the vertical line. Further, the lid heating coil 8 is configured to be included in a coil opening portion at the winding center portion of the side surface heating coil 5.

  In the induction heating rice cooker according to the first embodiment, a steam generation unit 50 is provided. The steam generating unit 50 includes a water container 9 that is a detachable and substantially bottomed cylindrical container in the rice cooker body 1, a water container storage unit 10 that stores the water container 9, and a container heating coil 11. ing. In the steam generation part 50, it is the structure which induction-heats the water container 9 with the magnetic field which the container heating coil 11 generate | occur | produces.

  The positional relationship of the container heating coil 11 with respect to the side heating coil 5 is not included in the position where the coil opening portion of the container heating coil 11 does not intersect the coil opening portion of the side heating coil 5 when the rice cooker is viewed from above. Placed in position.

  Moreover, the bottom part of the rice cooker body 1 has a bottom surface inverter circuit 18 (see FIG. 2) for supplying high-frequency current to the bottom surface heating coil 4, and a lid / side surface for supplying high-frequency current to the side surface heating coil 5 and the lid heating coil 8. A heating substrate 12 is disposed on which an inverter circuit 19 (see FIG. 2) and a container inverter circuit 33 (see FIG. 2) for supplying a high-frequency current to the container heating coil 11 are mounted.

  Furthermore, inside the outer lid 6 are mounted a control circuit 29 for controlling the bottom inverter circuit 18, the lid / side inverter circuit 19 and the container inverter circuit 33, and operation keys for operating the rice cooker. A control board 13 is arranged.

  In FIG. 1, as illustrated by a two-dot chain line, a reflecting frame 32 in which an aluminum material is wound in a loop shape is disposed on the outer periphery of the bottom surface heating coil 4, and cancels the leakage magnetic field from the bottom surface heating coil 4. In this way, the current flows.

  In the induction heating type rice cooker (200V specification) of Embodiment 1, the auxiliary coil 24 is connected in series to the series circuit of the lid heating coil 8 and the side surface heating coil 5 (see FIG. 2). The auxiliary coil 24 is disposed between the reflection frame 32 and the heating substrate 12. That is, the auxiliary coil 24 is disposed on the outer peripheral side with respect to the reflection frame 32. By arranging the auxiliary coil 24 in this manner, the magnetic field leaking from the auxiliary coil 24 is blocked by the aluminum reflecting frame 32 so that the pan 2 is not affected by heating.

  One terminal wire of the auxiliary coil 24 is connected to one terminal wire of the side surface heating coil 5 via a relay connector, and the other terminal wire of the auxiliary coil 24 is connected to a board connector provided on the heating board 12. ing.

  When applying the circuit configuration of the 200V specification induction heating rice cooker that is the second voltage specification configured as described above to the 100V specification induction heating rice cooker that is the first voltage specification, The auxiliary coil 24 connected by the connector between the heating coil 5 and the switching element of the heating substrate 12 can be removed, and the side surface heating coil 5 can be directly connected to the connector of the switching element of the heating substrate 12 to cope with it.

  However, the configuration in which the side surface heating coil 5 is connected to the switching element of the heating substrate 12 via the connector as described above is an example, and for example, a configuration in which the auxiliary coil is connected to the lid heating coil by a connector may be used. Moreover, the structure which connects the auxiliary coil directly to a cover heating coil or a side surface heating coil may be sufficient instead of the structure which connects the auxiliary coil 24 via a connector.

  FIG. 2 is a principal circuit diagram showing a part of the configuration of the induction heating rice cooker according to the first embodiment of the present invention. The induction heating type rice cooker shown in FIG. 2 is an example of a 200 V specification rice cooker in which the input AC power supply 14 is the second voltage.

  As shown in FIG. 2, when the rice cooker is connected to the AC power source 14, full-wave rectification is performed via a diode bridge 15 mounted on the heating substrate 12, and a bottom inverter circuit is connected via a choke coil 16 and a capacitor 17. 18, the lid / side inverter circuit 19 and the container inverter circuit 33 are supplied with power. The induction heating rice cooker of the first embodiment is provided with a power supply voltage detection circuit 30 that detects the power supply voltage of the AC power supply 14.

  The bottom inverter circuit 18 includes a capacitor 20 connected in parallel to the bottom heating coil 4 and a switching unit 23 connected in series to a parallel circuit of the bottom heating coil 4 and the capacitor 20. The switching unit 23 includes an IGBT 22 that is a switching element, and a diode 21 that is reversely connected to the IGBT 22.

  The circuit configuration of the bottom inverter circuit 18 is generally called a monolithic voltage resonance circuit because the voltage of the heating coil and the capacitor is resonated by turning on and off one switching element. The bottom inverter circuit 18 supplies a high-frequency current IL1 to the bottom heating coil 4.

  In the lid / side inverter circuit 19, a capacitor 25 is connected in parallel to a series circuit in which the lid heating coil 8, the side heating coil 5, and the auxiliary coil 24 are connected in series to form a parallel circuit. A switching unit 28 is connected in series to this parallel circuit. The switching unit 28 includes an IGBT 27 that is a switching element, and a diode 26 that is reversely connected to the IGBT 27.

  The circuit configuration of the lid / side inverter circuit 19 is also generally referred to as a monolithic voltage resonance circuit, similar to the bottom inverter circuit 18 described above. The lid / side inverter circuit 19 supplies a high-frequency current IL 2 to the side heating coil 5 and the lid heating coil 8.

  As shown in FIG. 2, similarly to the bottom inverter circuit 18 and the lid / side inverter circuit 19, in the container inverter circuit 33 that drives the container heating coil 11, a capacitor is connected in parallel to the container heating coil 11. The switching unit 34 is connected in series to this parallel circuit. The switching unit 34 is configured in the same manner as the other switching units 23 and 28.

  The circuit configuration of the container inverter circuit 33 is also generally called a one-stone voltage resonance circuit. The container inverter circuit 33 supplies a high-frequency current IL3 to the container heating coil 11.

  In the induction heating type rice cooker of the first embodiment, the auxiliary coil so that the total inductance value of the lid heating coil 8, the side surface heating coil 5, and the auxiliary coil 24 shown in FIG. 2 is in the range of about 70 μH to 80 μH. 24, the total inductance value is adjusted.

  In the series circuit of the lid heating coil 8, the side surface heating coil 5, and the auxiliary coil 24 in the induction heating rice cooker of the first embodiment, the auxiliary coil 24 is located on the side of the switching element 28 that is electrically farthest from the AC power supply 14. The auxiliary coil 24 is connected to a circuit that is electrically separated from the AC power supply side as compared with the lid heating coil 8. That is, the side heating coil 5 is connected to the auxiliary coil 24, the lid heating coil 8 is connected to the side heating coil 5, and the lid heating coil 8 is connected so as to be electrically closest to the AC power source 14. Has been. In other words, the lid heating coil 8 is connected to the choke coil 16 and the capacitor 17 in the subsequent stage of the full-wave rectifier circuit having the diode bridge 15.

  With the above configuration, when the lid / side inverter circuit 19 operates and a high frequency current flows through the series circuit of the lid heating coil 8, the side heating coil 5, and the auxiliary coil 24 to generate a resonance voltage, The voltage is divided by the heating coil 8, the side heating coil 5, and the auxiliary coil 24, and the maximum voltage of the lid heating coil 8 is lowered. For this reason, the value of the current flowing through the lead wire from the lid heating coil 8 to the AC power supply side becomes small, and the applied voltage of the lead wire also becomes low. The lead wire connected from the lid heating coil 8 provided in the outer lid 6 to the AC power supply side element provided in the rice cooker main body 1 is inside the hinge portion connecting the outer lid 6 and the rice cooker main body 1. It is configured to pass through. For this reason, it is necessary to ensure a desired insulation distance between the lead wire and another member in the space in the hinge portion. In the configuration of the first embodiment, since the maximum voltage of the lid heating coil 8 is set low as described above, it is possible to reduce the insulation distance between the lead wire and other members in the hinge portion or the like. .

  As described above, in the configuration of the induction heating rice cooker according to the first embodiment, it is not necessary to secure a large insulation distance as a space for passing the lead wire from the lid heating coil 8 to the AC power supply side, and the outside is a lid. The lid 6 can be made compact. As a result, the external shape of the rice cooker can be reduced.

  In the configuration of the induction heating type rice cooker of the first embodiment, when the rice cooker is viewed from above, the bottom surface heating coil 4 is wound so that the high-frequency current IL1 flows clockwise. The side surface heating coil 5 is wound so that the high-frequency current IL2 flows clockwise, and the lid heating coil 8 is wound so that the high-frequency current IL2 flows counterclockwise.

  In the configuration of the induction heating rice cooker according to the first embodiment, the control circuit 29 mounted on the control board 13 includes the bottom inverter circuit 18, the lid / side inverter circuit 19, and the container inverter circuit 33 on the heating board 12. To control the energization state and oscillation frequency.

  A power supply voltage detection circuit 30 for detecting the power supply voltage of the AC power supply 14 is provided, and the power supply voltage detection circuit 30 outputs a voltage corresponding to the power supply voltage of the AC power supply 14 to the control circuit 29. In the induction heating rice cooker according to the first embodiment, although not particularly illustrated, the output of the voltage dividing circuit in which the power supply voltage detection circuit 30 is configured by connecting two or more resistors in series is used as the emitter follower circuit of the transistor. The peak hold is used. However, this configuration is merely an example, and the power supply voltage detection circuit 30 may directly output an instantaneous value of the power supply voltage to the control circuit 29.

  FIG. 3 is a principal circuit diagram showing a part of the configuration of the induction heating rice cooker according to the first embodiment of the present invention in a block form, in which the input AC power supply 14 is the first voltage of 100V. It is an example of a specification rice cooker.

  The configuration of the induction heating rice cooker shown in FIG. 3 is different from the configuration of the induction heating rice cooker shown in FIG. 2 in that the auxiliary coil 24 is removed and the control circuit 31 shown in FIG. Is a rice cooking course corresponding to an area where a 100 V rice cooker is used, and the control circuit 31 is configured so as to be compatible with the output voltage of the power supply voltage detection circuit 30. Since the other structure is the same as that of the induction heating type rice cooker shown in FIG. 2, the description is abbreviate | omitted here.

FIG. 4 shows an example of the configuration of the auxiliary coil 24 used in the induction heating rice cooker of the first embodiment. The auxiliary coil 24 is configured by winding a coil wire 42 around a ferrite 41. One of the lead wires at both ends of the coil wire 42 is connected to a substrate connector 44 provided on the heating substrate 12, and the other is connected to a relay connector 45 connected to the side surface heating coil 5. The ferrite 41 of the auxiliary coil 24 is a columnar one having a cross-sectional area of about 50 mm ² and a length of about 50 mm. As the coil wire 42 of the auxiliary coil 5, lead wires used in the side surface heating coil 5 and the lid heating coil 8 are used. The lead wire is wound about 30 turns around the ferrite 41 and has an inductance of about 30 to 40 μH. Configured to be a value.

  The auxiliary coil 24 configured as described above can increase the inductance value with a simple configuration with respect to the series circuit of the side surface heating coil 5 and the lid heating coil 8, and has a compact configuration and can be processed. It is easy. Therefore, the auxiliary coil 24 has a configuration that can be easily mounted inside the rice cooker. Further, when the lid heating coil 8 or the side surface heating coil 5 is created, the auxiliary coil 24 can be created together, so that it becomes easier to manufacture as a rice cooker. Further, the auxiliary coil 24 configured as described above uses a rod-like ferrite, so that it is less likely to saturate than a closed magnetic circuit ferrite, and the inductance value is less likely to fluctuate even with a large current, so a stable inductance value is ensured. It becomes the structure which can do.

  The auxiliary coil 24 shown in FIG. 4 is connected between the board connector 44 and the relay connector 45, and the lead wire 43 connected to the side surface heating coil 5 is between the board connector 44 and the relay connector 45. Is also connected. The lead wire 43 is used for bypassing the auxiliary coil 24 in a state where the auxiliary coil 24 is removed when the power supply voltage is used in a 100V region as the first voltage system. Accordingly, when the rice cooker is used in a region where the power supply voltage is 100V, the lead wire 43 that bypasses the auxiliary coil 24 is used, and when the rice cooker is used in the 200V region as the second voltage system, the auxiliary is used. Since the coil 24 is used, it is possible to easily cope with the problem by simply changing the connection state of the connector.

  In the configuration of the first embodiment, the auxiliary coil 24 is disposed in a region between the heating substrate 12 and the reflection frame 32 as described with reference to FIG. As an arrangement method of the auxiliary coil 24, an auxiliary coil attachment portion may be provided on the heating substrate 12 and may be fitted into the auxiliary coil attachment portion, or may be attached to the outer surface of the reflection frame 32. It may be configured.

  The method for arranging the auxiliary coil 24 is not limited to the above-described arrangement method, and an auxiliary coil attaching portion is provided in the region outside the reflection frame 32 inside the rice cooker body 1 to assist the auxiliary coil 24. You may attach to a coil attaching part.

  FIG. 5 shows an example of another connection method when the auxiliary coil 24 is connected to the heating substrate 12. In the auxiliary coil 24 configured by winding the coil wire 42 around the ferrite 41, both ends of the lead wire are connected to the board connector 44. Therefore, in the connection method shown in FIG. 5, the auxiliary coil 24 is connected in series to the lead wires of the side surface heating coil 5 and the lid heating coil 8 on the heating substrate 12 via the terminals of the substrate connector 44. Has been. Accordingly, when the rice cooker is used in a region where the power supply voltage is 100V or 200V, the auxiliary coil 24 can be easily connected and separated by changing the connection state of the board connector 44.

  In the induction heating type rice cooker of Embodiment 1 configured as described above, the power supply voltage of the AC power supply 14 is a 200 V system, and in the case of a 200 V specification rice cooker, using FIG. 1 and FIG. The operation and action will be described.

  First, in the induction heating type rice cooker of the first embodiment, the pot 2 and the water container (container) 9 are set at predetermined positions of the rice cooker main body 1, and the user sets a desired rice cooking mode with the operation keys. The rice cooking operation is started by operating the start switch for the rice cooking operation. In this rice cooking operation, the control circuit 29 heats the bottom and side portions of the pan 2, the lid heating unit 7 and the water container 9 based on the rice cooking sequence set in advance according to the set rice cooking mode. The operation of the bottom inverter circuit 18, the lid / side inverter circuit 19 and the container inverter circuit 33 is controlled.

  At this time, the control circuit 29 determines whether the power supply voltage of the AC power supply 14 is a 100V system or a 200V system based on the output voltage of the power supply voltage detection circuit 30. If the control circuit 29 determines that the output voltage of the power supply voltage detection circuit 30 is only half that of the 200V system, the control circuit 29 determines that the AC power supply 14 is a 100V system and cooks rice. Stops the start of operation.

  However, in the case where the power supply voltages to be input are different as described above, the configuration in which the start of the rice cooking operation is simply stopped is an example, and the abnormality may be notified after the rice cooking operation is stopped. In 100V specification rice cooker and 200V specification rice cooker, parts of inverter circuit including heating coil may be divided and used, and when power supply voltage is different from specification, rice cooking performance is fully demonstrated There are things that cannot be done.

  Therefore, by notifying the user that the power supply voltage of the AC power supply 14 is different, the user can easily determine that the rice cooker is about to perform a rice cooking operation in a region where the power supply voltage is different. This makes it easier for the user to consult with the dealer.

  When the control circuit 29 determines that the output voltage of the power supply voltage detection circuit 30 is normal, when the rice cooking operation is started and the bottom of the pan 2 is controlled to be heated, a drive signal is transmitted to the bottom inverter circuit 18, and the pan When controlling the heating of the side surface portion 2 and the lid heating unit 7, a drive signal is transmitted to the lid / side surface inverter circuit 19, and when the water container 9 is controlled to be heated, a drive signal is transmitted to the container inverter circuit 33. As a result, the bottom inverter circuit 18 supplies the desired high-frequency current IL1 to the bottom heating coil 4, and the lid / side inverter circuit 19 supplies the desired high-frequency current IL2 to the side heating coil 5, the lid heating coil 8, and the auxiliary coil 24. The container inverter circuit 33 supplies a desired high-frequency current IL3 to the container heating coil 11.

  At this time, the high-frequency current IL2 supplied to the side heating coil 5, the lid heating coil 8, and the auxiliary coil 24 flows clockwise in the side heating coil 5 when viewed from above the rice cooker, and in the lid heating coil 8, the rice cooking. It flows counterclockwise when viewed from above the vessel.

  That is, the same current flows in the opposite direction in the side surface heating coil 5 and the lid heating coil 8. Among these currents, the high-frequency current having a high-frequency component becomes a high-frequency magnetic field, and is magnetically coupled to the side surface portion of the pan 2 and the lid heating unit 7 so that a high-frequency eddy current flows. Induction heating.

  In the high-frequency current IL2, a low-frequency magnetic field corresponding to a component twice that of the AC power source 14 (a frequency component of 120 Hz when the frequency of the AC power source 14 is 60 Hz) is applied to the side surface portion of the pan 2 and the lid heating unit 7. Magnetic coupling is not sufficient, and eddy currents are not generated, and low-frequency leakage magnetic fields can be obtained.

  However, in the configuration of the first embodiment, since the same current flows in the side heating coil 5 and the lid heating coil 8 in the opposite directions, the low frequency leakage magnetic fields generated by each other cancel each other out. The leakage magnetic field that leaks to the outside is greatly reduced.

  In the configuration of the first embodiment, since the auxiliary coil 24 is connected in series with the lid heating coil 8 and the side surface heating coil 5, the high-frequency current IL2 also flows through the auxiliary coil 24. However, since the auxiliary coil 24 is disposed outside the reflection frame 32 in the rice cooker body 1, the auxiliary coil 24 contributes to heating both the lid heating unit 7 and the side surface of the pan 2. There is no. In the first embodiment, the auxiliary coil 24 is provided with an inductance value for ensuring a resonance voltage so that an abnormal turn-on voltage is not generated when the switching unit 28 is turned on.

  In the induction heating rice cooker of the 200V specification that is the second voltage specification, as shown in FIG. 2, the auxiliary coil 24 is connected to the series circuit of the lid heating coil 8 and the side surface heating coil 5, so that FIG. The total inductance value of the lid heating coil 8 and the side heating coil 5 in the induction heating rice cooker of the 100 V specification, which is the first voltage specification shown in Fig. 2, is 40 µH to 50 µH, and the auxiliary coil 24 is attached. Therefore, the total inductance value is 70 μH to 80 μH.

  As described above, compared to the total inductance value of the series circuit of the lid heating coil 8 and the side surface heating coil 5 in the induction heating rice cooker of 100V specification, the total inductance value in the induction heating rice cooker of 200V specification is about Since the auxiliary coil 24 can be mounted so as to increase from 1.5 times to 2 times, even if the power supply voltage of the AC power supply 14 is doubled (for example, 100 V to 200 V), it is sufficiently resonated by the heating coil and the capacitor. It becomes the structure which can be done.

  When the AC power supply 14 uses the rice cooker in a 100V system area, as shown in FIG. 3, the auxiliary coil 24 is removed, and only the series circuit of the lid heating coil 8 and the side surface heating coil 5 is configured. Thus, it becomes possible to deal with 100V region. By comprising in this way, it becomes possible to drive the cover heating part 7 and the side part of the pan 2 by the cover / side inverter circuit 19 without changing the heating ratio.

  As mentioned above, in Embodiment 1 which concerns on this invention, it has the structure which connects the side surface heating coil 5 and the lid | cover heating coil 8 in series, and in the 200V specification rice cooker which is a 2nd voltage specification rice cooker. The auxiliary coil 24 is further connected in series to the series circuit of the side surface heating coil 5 and the lid heating coil 8. By comprising in this way, in the 200V specification rice cooker which is a 2nd voltage specification rice cooker, and the 100V specification rice cooker which is a 1st voltage specification rice cooker, attach or remove an auxiliary coil. Thereby, it can prevent that the heating ratio of the lid | cover heating part 7 and the side part of the pan 2 in a rice cooker used in a 100V system area and a 200V system area changes. For this reason, according to this invention, it is the structure which can provide easily the induction heating type rice cooker used in the area where a power supply voltage changes.

  In the configuration of the first embodiment, the side surface heating coil 5 is wound so that the high-frequency current IL2 flows clockwise, and the lid heating coil 8 is wound so that the high-frequency current IL2 flows counterclockwise. The same current is configured so that the high-frequency current flows in the opposite direction, but the same effect can be obtained even if each heating coil is wound in the opposite direction so that each high-frequency current flows in the opposite direction. It is what you have.

  In the configuration of the first embodiment, since the input power of the lid / side inverter circuit 19 is about 300 W, the auxiliary coil 24 has a configuration in which a coil wire (a lead wire of a heating coil) is wound around the ferrite 41. The configuration of the auxiliary coil 24 is not limited to such a configuration, and a litz wire may be used or an air-core coil may be used, which is appropriately set according to the specifications of the rice cooker.

  In the first embodiment, the case where the power supply voltage of the AC power supply 14 is the 100V system as the first voltage system and the case where the power supply voltage is the 200V system as the second voltage system has been described. The auxiliary coil is connected to the side heating coil and the lid heating so that the series circuit of the side heating coil and the lid heating coil has a desired inductance value with respect to the power supply voltage used in various parts of the world. What is necessary is just to be able to connect in series with the series circuit of a coil, and to be comprised so that the said series circuit may have a desired inductance value.

  As described above, the induction heating rice cooker according to the present invention is configured so that the auxiliary coil can be connected in series to the series circuit of the lid heating coil and the side heating coil, and the power supply voltage of the AC power supply is, for example, 100V In this case, it is necessary to change the heating ratio of the lid heating part and the side part of the pan even in different power supply voltage system areas by removing the auxiliary coil, for example, in the case of 200V system, by attaching the auxiliary coil. Therefore, the power supply voltage system can easily cope with different areas.

  Since the induction heating type rice cooker of the present invention has a configuration that can easily cope with regions having different power supply voltages, the rice cooker can easily correspond to an overseas market as an export product. It will be a useful rice cooker that can expand the market scale.

DESCRIPTION OF SYMBOLS 1 Rice cooker body 2 Pan 4 Bottom heating coil 5 Side heating coil 6 Outer lid 7 Lid heating part 8 Lid heating coil 11 Container heating coil 14 AC power source 18 Bottom inverter circuit 19 Lid / side inverter circuit 24 Auxiliary coil 29, 31 Control circuit 30 Power supply voltage detection circuit 32 Reflecting frame 41 Ferrite 42 Coil wire (lead wire)
43 Lead wire 44 Board connector 45 Relay connector

Claims (5)

A rice cooker body that is supplied with power from an AC power source and performs rice cooking operation;
A pot housed inside the rice cooker body;
A bottom heating coil for induction heating the bottom of the pan;
A bottom inverter circuit for supplying a high-frequency current to the bottom heating coil;
An outer lid covering the pan so as to be freely opened and closed;
A lid heating coil for inductively heating the outer lid;
A side heating coil for induction heating the side of the pan;
A lid / side inverter circuit for supplying a high-frequency current to the lid heating coil and the side heating coil;
A control circuit that controls the bottom surface inverter circuit and the lid / side surface inverter circuit to supply a high-frequency current to the bottom surface heating coil, the lid heating coil, and the side surface heating coil according to a rice cooking operation; ,
The lid heating coil and the side surface heating coil are connected in series, and an auxiliary coil can be connected in series with respect to the series circuit of the lid heating coil and the side surface heating coil. An induction heating rice cooker configured such that the auxiliary coil can be connected to and separated from the power supply voltage.   The auxiliary coil is composed of a single coil different from the lid heating coil and the side surface heating coil. When the power supply voltage of the AC power source is the first voltage system, the auxiliary coil is removed, and the AC The induction heating rice cooker according to claim 1, wherein the auxiliary coil is attached when the power supply voltage of the power supply is a second voltage system.   The series circuit of the said cover heating coil, the said side surface heating coil, and the said auxiliary coil WHEREIN: The said auxiliary coil was connected to the circuit electrically separated from the said AC power supply side compared with the said cover heating coil. The induction heating rice cooker described.   The induction heating rice cooker according to any one of claims 1 to 3, wherein the auxiliary coil is configured by winding a wire equivalent to a lead wire of the lid heating coil or the side surface heating coil around a rod-shaped ferrite. . 5. The induction heating according to claim 1, further comprising a loop-shaped reflection frame made of a metal material on an outer periphery of the bottom heating coil, wherein the auxiliary coil is disposed on the outer periphery side of the reflection frame. Type rice cooker.

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