JP3123691B2 - Induction heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating cooker for cooking rice in an inner pot by an electromagnetic induction heating method.

[0002]

2. Description of the Related Art Conventionally, this type of induction heating cooker generally has a configuration as shown in FIG. 3 (see, for example, Japanese Utility Model Laid-Open No. 1-170991). In FIG. 3, a heater 2 is affixed to a cylindrical heat radiation ring 1 made of a metal material, and an inner container 2 made of a non-metal material.
The heat radiating ring 1 is also fixed to the main body upper frame 4 by screwing the main body frame 3 and the main body upper frame 4 at a plurality of places. The induction heating coil 7 is arranged between the inner container 23 and the coil base 6. An inverter circuit 14 for driving the induction heating coil 7 is connected to the induction heating coil 7.

A body 16 having an inverter circuit 14 attached to the bottom is attached to the main body upper frame 4, and a lid 17 is attached to the main body upper frame 4 so as to be openable and closable. An inner pot 18 is detachably stored inside the main body upper frame 4 and the inner container 23. A temperature sensor 20 for detecting the temperature of the inner pot 18 is fitted in the center hole of the coil base 6 by being urged upward and brought into contact with the bottom of the inner pot 18 to have substantially the same temperature thermally.

An appropriate amount of rice and water are put in an inner pot 18 and an inner container 2
When the rice cooker 3 is closed and the lid 17 is closed and the rice cooking operation is performed, the heater 2 is energized, and the heat generated by the heater 2 is conducted to the heat radiating ring 1, and the entire heat radiating ring 1 becomes high temperature. This heat is transmitted to the side of the inner pot 18 by radiation, and heats the rice and water inside. At the same time, the inverter circuit device 14 also starts to operate, converts the commercial power to high frequency,
Start energization. An eddy current is generated in the inner pot 18 by a high-frequency magnetic field generated by the principle of electromagnetic induction heating,
Is converted into Joule heat by the electric resistance of the inner pot 18 and generates heat, thereby heating rice and water inside the inner pot 18.

[0005] The inner pot 18 heated by the heater 2 and the induction heating reaches a temperature of one hundred and several degrees Celsius when the water inside boils shortly. Since the inner container 23 facing the inner pot 18 receives heat by the radiation of the inner pot 18, the temperature of the inner container 23 side surface becomes close to 100 ° C. The bottom of the inner container 23 is opposed to the bottom of the inner pot 18 which is close to the induction heating coil 7 and has a high temperature, and further receives heat from the induction heating coil 7 which generates heat due to loss, and thus has a high temperature of one hundred and several tens of degrees Celsius.

When the water in the inner pot 18 runs out, the bottom of the inner pot 18 rapidly rises in temperature. The temperature rise is detected by the temperature sensor 20, and the rice cooking is terminated. Thereafter, the heating by the heater 2 and the induction heating coil 7 is switched to minute heating for keeping the temperature in the inner pot 18 at a hundred and several degrees Celsius, and the process shifts to a spotting process. During the rapid temperature rise at the end of the rice cooking and during the watering process, since there is no water in the inner pot 18, the bottom of the inner pot 18 becomes hotter than during the rice cooking, and the inner container 23 is heated.
The temperature at the bottom is even higher.

If the user accidentally spills water, the water will collect at the bottom of the inner container 23, and will flow below the hole for mounting the temperature sensor 20 at the center of the bottom of the inner container 23, causing the water to flow on the body 16. It is led to.

[0008]

In the conventional induction heating cooker shown in FIG. 3, an inner container 23 which comes into contact with the induction heating coil 7 is used.
Is formed integrally from the bottom affected by the magnetic field to the middle of the side surface, and becomes a large bowl-shaped part. However, the inner container 23
The non-metallic material that constitutes is required not only to not generate heat by induction heating but also to have severe performance as follows.

The inner pot 18 which has generated heat by induction heating has heat resistance. In addition, since water droplets often adhere to the outer periphery of the inner pot 18 at the time of washing rice or the like, the material does not absorb water and change in characteristics and dimensions does not occur. Also,
It is necessary to protect the induction heating coil 7, which is subject to high temperature and high voltage, from the outside so that the user cannot touch it.
Rapid cooling (thermal shock) such as accidentally applying water from a high temperature state
Even if something is dropped (shock) by mistake, it must not be easily broken.

Since the magnetic field generated by the induction heating coil 7 becomes weaker as the distance increases, the distance between the induction heating coil 7 and the inner pot 18 has a significant effect on the heating power, so that processing and molding with stable dimensions can be performed. Dimensional stability such that it does not expand or contract or warp even at high temperatures. In addition, since it is a part that can be seen when the inner pot 18 is removed and the inside of the main body is viewed, it is easy to be colored and has an appearance with excellent gloss and quality. Furthermore, such performance must be maintained for a long time. And so on.

From the above, as a non-metallic material constituting the inner container 23, a general plastic material cannot satisfy the above-mentioned performance, and has heat resistance, resistance to cold and heat destruction, impact resistance,
Insulation properties and the like are required, and very expensive and special materials such as nylon resin containing a large amount of glass are used. In the conventional configuration, not only the point directly touched by the induction heating coil 7 but also the entire range affected by the magnetic field is made of this material, so that it becomes a large part, so that a large amount of expensive material is used, and there are many restrictions on molding. The molding cost was also higher than that of a general resin, and was naturally an expensive component.

In order to solve such a problem, as shown in, for example, Japanese Patent Application Laid-Open Nos. 1-144591 and 1-2218414, an inner container (protection frame) for accommodating an inner pot in a main body is provided. It consists of a bottom part made of non-metallic material and a side part made of metal material.The parts that require expensive materials are reduced in size, and an induction heating coil in which electric wires are formed in a coil shape at the bottom of the inner container is arranged. There is a configuration in which the inverter circuit device is attached to the bottom inside the main body. The bottom of the inner container is made of a non-metallic material in order to prevent the inner container from being induction heated by the high frequency magnetic field of the induction heating coil.
The connection with the side parts is complicated.

However, in the above-mentioned example, as in the conventional example shown in FIG. 3, the inverter circuit device 14 for the induction heating cooker is a very heavy component, and therefore, the conveyance / loading during use of the induction heating cooker and the distribution route. In order to prevent damage to the main body and the inverter circuit device 14 due to a drop impact during handling, etc., the inverter circuit device 14 is firmly fixed to the body 16, and the induction heating coil 7 and the inverter circuit 14 are connected. It is attached to the upper frame 4 of the main body, and closes the main body provided with the induction heating coil 7, the inner container 23, and the like.
There is a problem that assembly is difficult.

In order to improve the assembling, as shown in Japanese Patent Application Laid-Open No. 189309/1992, an inner container for accommodating an inner pot is provided in a main body, and an induction heating coil is provided at the bottom of the inner container. In order to mount the inverter circuit device on the inner container side instead of the bottom side of the body, a board case that covers the induction heating coil and the inner container bottom is provided, and the inverter circuit device is mounted on this board case. However, since the induction heating coil is attached to the bottom of the inner container, the temperature rises to a high temperature, and the strength is reduced. However, the strength is still insufficient for installing an inverter circuit device. Also in this example, the inner bottom is made of a non-metallic material so that the inner container is not induction-heated by the high-frequency magnetic field of the induction heating coil, and the connection with the side portion is complicated.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an inner pot accommodated in a main body by a high-frequency magnetic field generated from an induction heating coil connected to an inverter circuit device. An induction heating cooker that heats and cooks by heating a heating unit configured by sandwiching an induction heating coil between an upper inner container bottom and a lower coil base, and further has a vertically open cylindrical shape and a main body inner wall. A heating unit holding part is provided below the inner container, and the heating unit is inserted from the opening direction of the inner container and fixed to the heating unit holding part with screws or the like. .

Alternatively, a substrate case holding an inverter circuit device is provided below the inner container, and the heating unit is inserted from the upper opening direction of the inner container. The heating unit may be fixed more firmly by screwing the heating unit to the upper side of the substrate case.

Further, a drooping portion having an inner diameter larger than the outer diameter of the induction heating coil and drooping downward is provided on the entire lower surface of the bottom of the inner container, and extends downward from the inner diameter of the inner diameter to the inner side of the inner diameter of the dripping portion below the inner container. A groove is provided, and a plurality of holes are provided in the groove to receive water that has entered through a gap between the inner container and the bottom of the inner container, and drain the water from the hole.

The bottom of the inner container is made of a small non-metallic dish made of a nylon resin or the like containing a large amount of glass having excellent heat resistance, resistance to cold and heat destruction, impact resistance, insulation and the like.

[0019]

According to the structure of the present invention, the divided open cylindrical inner container is not affected by the magnetic field but does not touch the induction heating coil or the like which becomes high during heating and cooking. In addition, the bottom of the small dish-shaped inner container touches the induction heating coil and becomes hot during cooking, and is affected by the magnetic field.
Excellent heat resistance, resistance to cold and heat destruction, impact resistance, insulation, etc., and stable dimensions in terms of shape. The heating unit holding portion and the substrate case can firmly fix the heating unit with screws or the like.

Further, by mounting the substrate case holding the inverter circuit device separately from the induction heating coil to an inner container which does not become high in temperature and does not deteriorate in strength, the weight of the heavy inverter circuit device can be endured and the connection work becomes easy.

When a user spills water or the like, the groove having a plurality of holes receives water that has entered through the gap between the inner container and the bottom of the inner container and acts to drain water from the holes.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of an induction heating cooker in which one embodiment of the present invention is applied to a rice cooker, and FIG. 2 is a sectional view of an induction heating cooker in which another embodiment is applied.

The structure will be described with reference to FIG. 1. A cylindrical heat radiation ring 1 made of a metal material has a heater 2 attached thereto.
The heat dissipating ring 1 is also fixed to the main body upper frame 4 by fixing the inner container 3 and the main body upper frame 4 with screws at a plurality of locations. An induction heating coil 7 is sandwiched and screwed together by an upper inner container bottom 5 and a lower coil base 6 to form a heating unit 8. The heating unit 8 is inserted from above the inner container 3 and is screwed to a heating unit holding portion 9 formed below the inner container 3.

On the lower surface of the inner container bottom portion 5, a drooping portion 10 having an inner diameter larger than the outer diameter of the induction heating coil 7 and hanging downward is formed all around. A step portion 11 is provided in the middle lower part of the inner container 3, and the outer periphery of the hanging portion 10 and the inner periphery of the step portion 11 are in contact with the entire circumference.
A groove 12 extending from the inner diameter to the inside is formed over the entire circumference, and holes 13 are formed at a plurality of positions of the groove 12. An inverter circuit device 14 is provided on the lower surface of the inner container 3.
Is fixed with screws. The inner container 3 may be made of general plastics as long as it is a non-magnetic material. For example, the inner container 3 may be made of polypropylene. The inner container bottom portion 5 may contain a suitable material having excellent heat resistance, insulation, impact resistance, etc., for example, 50% glass. Made of nylon.

A body 16 is attached to the upper frame 4 of the main body, and a lid 17 is further attached to be openable and closable.
An inner pot 18 is detachably housed inside the upper frame 4 and the inner container 3. A control unit 19 is provided inside the body 16, and the control unit 1 is operated by operating an operation panel (not shown) provided on the front surface of the body 16.
An operation signal is sent to 9.

A temperature sensor 20 is held between the substrate case 15 and the inner container bottom 5 and is provided so as to protrude from a hole in the center of the inner container bottom 5. It comes into contact with the bottom and becomes substantially the same temperature as the bottom of the inner pot 18.

Terminal terminal of induction heating coil 7 (not shown)
And the inverter circuit device 14 are electrically connected, and the control unit 19, the heater 2, and the inverter circuit device 1
4 and the temperature sensor 20 are electrically connected.

In FIG. 2, the heating unit 8 is first attached to the inner container 3.
So that the coil base 6 of the heating unit 8 can be temporarily fixed.
The heating unit 8 and the heating unit holding unit 9 are fixed by the claws 6a. Next, the substrate case 15 is screwed to the lower surface of the inner container 3, and the heating unit 8 is screwed to the substrate case 15. The other configuration is the same as that of FIG.

Next, a description will be given of the operation of the induction heating cooker of the present configuration in the case of cooking rice as a main function in a general use procedure.

The user puts the polished rice and an appropriate amount of water into the inner pot 18, opens the lid 17, and sets the rice in the main body. The upper part of the inner container 3 and the upper frame 4 of the main body are in contact with each other, and the radiating ring 1, the inner container 3 and the inner container bottom 5 are separated from the inner pot 18 by a space.
8 so as to enclose them. Next, when the user closes the lid 17 and operates a rice cooker switch (not shown) on the operation panel, a signal is sent to the controller 19 to start a rice cooking operation. The heater 2 is energized by the control unit 19, and the heat generated by the heater 2 is conducted to the heat radiating ring 1,
The whole becomes hot. This heat is transmitted to the side of the inner pot 18 by radiation, and heats the rice and water inside.

On the other hand, at the same time, the control circuit 19 also starts the operation of the inverter circuit device 14 to convert the commercial power supply to a high frequency and start energizing the induction heating coil 7. An eddy current is generated in the inner pot 18 by a high-frequency magnetic field generated by the principle of electromagnetic induction heating, is converted into Joule heat by the electric resistance of the inner pot 18, generates heat, and heats rice and water inside the inner pot 18.

The inner pot 18 heated by the heater 2 and the induction heating will reach a temperature of one hundred and several degrees Celsius when the water in the inside is about to boil. Since the inner container 3 and the inner container bottom portion 5 facing the inner kettle 18 receive heat due to the radiation of the inner kettle 18, the temperature of the inner container 3 becomes nearly 100 ° C. The bottom 5 of the inner container is opposed to the bottom of the inner pot 18 which is close to the induction heating coil 7 and has a high temperature, and further receives heat from the induction heating coil 7 which generates heat due to loss, so that the temperature reaches a hundred and several tens of degrees Celsius.

Eventually, when the water in the inner pot 18 runs out, the temperature of the bottom of the inner pot 18 rapidly rises. The controller 19 detects the rapid temperature rise with the temperature sensor 20 and ends the rice cooking. Thereafter, the heating by the heater 2 and the induction heating coil 7 is switched to minute heating for keeping the temperature in the inner pot 18 at a hundred and several degrees Celsius, and the process shifts to a spotting process. During the rapid temperature rise at the end of the rice cooking and during the rice drying process, since there is no water in the inner pot 18, the temperature at the bottom of the inner pot 18 becomes higher than that during the rice cooking, and the temperature of the inner container bottom 5 further rises.

During the above-described series of rice cooking and rice drying operations, the inner container 3 and especially the inner container bottom 5 are exposed to high temperatures as described above. In addition, the water at the time of rice sharpening often adheres to the outer peripheral portion of the inner pot 18 and is exposed to high humidity. Accordingly, the material constituting the inner container 3 and the inner container bottom 5 has good heat resistance such that the material is not thermally deformed or deteriorated in addition to good appearance such as color and gloss (the inner container 18 is a hundred and several tens of degrees Celsius, 5 is more than 200 ℃)
In addition, it is required that the material be supplied with water and have moisture resistance that does not deteriorate.

Furthermore, since the inner bottom 5 protects the induction heating coil 7, which is subjected to a high temperature and a high voltage, from the outside and prevents the user from touching it, rapid cooling such as accidentally spraying water from the high temperature state. (Heat shock) or accidental dropping (shock) should not break easily.
Further, the magnetic field generated by the induction heating coil 7 becomes weaker as the distance increases, so that the distance between the inner pot 18 and the induction heating coil 7 has a significant effect on the heating power. Therefore, dimensional stability that does not significantly expand or contract or warp due to heat is also required.

From the above, in the present embodiment, the material forming the inner container bottom 5 is not a general resin material but is required to have heat resistance, cold / hot break resistance, impact resistance, insulation, and the like. Although it is an expensive material and has many restrictions in terms of molding and molding cost is higher than ordinary resins, the required performance is satisfied by using a 66 nylon resin containing 50% of glass. Therefore, only the part which touches the induction heating coil 7 and requires expensive material is the dish-shaped inner container bottom 5,
The amount of expensive materials used can be minimized, and such a shape has the effect that the dimensions are generally easily stabilized and the molding cost can be reduced.

Further, it is necessary to use a non-magnetic material up to the middle portion of the side surface affected by the magnetic field, and the inner container 3 is made of plastic. However, the performance such as heat resistance required here can be satisfied with a general material. , Made of polypropylene. Polypropylene has a heat resistance of about 130 ° C., and is inexpensive in cost, about 1/3 of the expensive material of the inner bottom part 5. As described above, the inner container 3 and the inner container bottom 5 can be divided to minimize the amount of expensive materials used, so that the structure can be reduced.

Next, a configuration in consideration of safety against misuse by the user and its operation will be described. If the user accidentally spills water inside the main body, most of the spilled water flows through the central hole of the inner container bottom part 5, flows through the board case 15 and onto the body 16. However, since the inner container bottom 5 has a dish-shaped shallow shape, water also flows into the joint between the inner container 3 and the inner container bottom 5, is transmitted through the inner container 3, and is guided to the groove 12. Further, a part of the water is transmitted to the back surface of the inner container bottom portion 5 and flows, but flows to the tip of the hanging portion 10 and drops into the lower groove portion 12 similarly.

Accordingly, since water does not enter the induction heating coil 7 beyond the hanging part 10, there is no danger of electric shock. The water that has flowed into the groove 12 is the hole 1 provided at a plurality of locations.
The water is drained from 3 and flows onto the body 16. Although not shown in the figure, the body 16 is provided with a plurality of holes, and is configured to drain water on the floor. As described above, safety can be ensured against misuse by the user.

Further, by mounting the substrate case 15 holding the inverter circuit device 14 separately from the induction heating coil 7 to the inner container 3 which does not become high in temperature and does not deteriorate in strength, the weight of the heavy inverter circuit device 14 can be endured and the inverter circuit device can withstand the weight. Device 14, heater 2, induction heating coil 7,
Connection work with the control unit 19, the temperature sensor 20, and the like is also facilitated.

In FIG. 1, a vertical dimension for screwing is required between the heating unit 8 and the heating unit holding portion 9, but in FIG. , The vertical dimension is not required, but since there is a distance between the heating unit 8 and the substrate case 15, it is possible to adopt a configuration in which the screw is easily screwed, and the height can be reduced. Yes, it saves space and improves usability such as eating rice.

[0042]

As described above, according to the present invention, a heating unit is constituted by sandwiching an induction heating coil between the bottom of the upper inner container and the lower coil base, and has a cylindrical shape with upper and lower openings and accommodates an inner pot. The inner wall of the main body is made up, and the induction heating coil is touched, and heat resistance, cold and heat resistance, impact resistance, insulation, etc. are required, and only those parts that require expensive materials are dish-shaped inner containers. Since it is the bottom, it is a very expensive material as the material for the bottom of the inner container. There are many restrictions on molding and the molding cost is higher than that of ordinary resin.
The required performance is satisfied by using 66 Nylon resin contained, the amount of expensive materials used can be minimized, and such a shape is generally more easily dimensionally stable, There is an effect that molding can be performed at low cost.

Further, the inner container needs to be made of a non-magnetic material up to the middle part of the side surface affected by the magnetic field by division. However, since the required performance such as heat resistance can be satisfied with a general material, It can be made of polypropylene having a degree of heat resistance, and has an effect that the cost can be reduced to about 1/3 of the expensive material at the bottom of the inner container.

The heating unit is inserted from the upper opening direction of the inner container and fixed to a heating unit holding portion provided below the inner container with screws or the like, or a substrate case is provided below the inner container for housing the inner pot. Is inserted from the opening direction of the inner container and held at the lower part of the inner container and fixed on the upper side of the board case, so that it is easy to assemble and has the effect that the heating unit etc. can be held firmly. Since the unit is fixed with the claw provided at the bottom of the inner container, there is no need for the vertical dimension, and there is a distance between the heating unit and the substrate case, so that it can be easily screwed, and the height can be increased. Can be reduced, space is saved, and usability such as eating rice is improved.

Since the inverter circuit device is held under the board case attached to the inner container which does not become high temperature and does not decrease in strength, the strength is sufficient, the assembling property is good, and the safety in case of spilling water is high. There is. In addition, a drooping portion having an inner diameter larger than the outer diameter of the induction heating coil is provided on the entire lower surface of the bottom of the inner container, and a groove having a plurality of holes extending inward from the inner diameter of the drooping portion is provided below the inner container. Water that has entered through the gap between the container and the bottom of the inner container is received in the groove, drained from the hole, and there is no important part where water below the hole is splashed.Therefore, even if the user accidentally spills water It is safe.

As described above, there is an effect that a consumer can be provided with an induction heating cooker as a cheap and safe rice cooker.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an induction heating cooker showing an example of a rice cooker according to an embodiment of the present invention.

FIG. 2 is a sectional view of an induction cooking device showing another embodiment of the present invention.

FIG. 3 is a sectional view of an induction heating cooker showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Inner container 5, Inner container bottom 6 Coil base 7 Induction heating coil 8 Heating unit 9 Heating unit holding part 10 Hanging part 12 Groove part 13 Hole part 14 Inverter circuit device 15 Substrate case 18 Inner pot

Claims (3)

(57) [Claims] An induction heating cooker for heating and cooking an inner pot (18) housed in a main body by a high-frequency magnetic field generated from an induction heating coil (7) connected to an inverter circuit device (14). , A heating unit (8) constituted by sandwiching the induction heating coil (7) between an upper inner container bottom (5) and a lower coil base (6), and further comprising a vertically open cylindrical body An inner container (3) that forms an inner wall and houses the inner pot (18) is provided. A heating unit holding portion (9) is provided below the inner container (3), and the heating unit (8) is attached to the inner container (3). ) Inserting from the upper opening direction and fixing it to the heating unit holding portion (9), and furthermore, a drooping portion (10) having an inner diameter larger than the outer diameter and drooping downward on the lower surface of the inner container bottom (5). Is provided below the inner container (3). The vertical portion (10) is provided with a groove (12) extending inward from the inner diameter to the inner side.
2) is provided with a plurality of outwardly directed holes (13) to receive water that has entered through the gap between the inner container (3) and the inner container bottom (5) through the groove (12). An induction heating cooker characterized in that it is configured to drain water. 2. An induction heating cooker for heating and cooking an inner pot (18) housed in a main body by a high-frequency magnetic field generated from an induction heating coil (7) connected to an inverter circuit device (14). , A heating unit (8) constituted by sandwiching the induction heating coil (7) between an upper inner container bottom (5) and a lower coil base (6), and further comprising a vertically open cylindrical body An inner wall (3) for forming the inner wall and accommodating the inner pot (18) is provided, and a substrate case (15) holding an inverter circuit device (14) on a lower side is provided below the inner container (3). The heating unit (8) is inserted from the upper opening direction of the inner container (3) to hold the heating unit (8) at the lower part of the inner container (3), and further, fix the heating unit (8) at the upper side of the substrate case (15). By the heating unit ( 8. An induction heating cooker characterized in that 8) is held more firmly. 3. An induction heating cooker for heating and cooking an inner pot (18) housed in a main body by a high frequency magnetic field generated from an induction heating coil (7) connected to an inverter circuit device (14). , A heating unit (8) constituted by sandwiching the induction heating coil (7) between an upper inner container bottom (5) and a lower coil base (6), and further comprising a vertically open cylindrical body An inner wall (3) for forming the inner wall and accommodating the inner pot (18) is provided, and a substrate case (15) holding an inverter circuit device (14) on a lower side is provided below the inner container (3). The heating unit (8) is inserted from the upper opening direction of the inner container (3) to hold the heating unit (8) below the inner container (3),
A heating unit (8) is fixed on the upper side of the substrate case (15), and a drooping portion (1) having an inner diameter larger than the outer diameter and drooping downward on the lower surface of the inner container bottom (5).
0), and the hanging part (10) is provided below the inner container (3).
A groove (12) extending in the inner circumferential direction from the inner diameter to the inside is provided, and the groove (12) has a plurality of outward holes (1).
Induction heating cooking, wherein 3) is provided, and water that has entered through a gap between the inner container (3) and the inner container bottom (5) is received by the groove (12) and drained from the hole (13). vessel.