JP2012195059A - Heating coil and induction heating cooker using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage on a top plate by reducing the weight of a heating coil thereby decreasing the inertia thereof thus reducing the shock when a product falls.SOLUTION: Since a copper clad aluminum conductor 39 is used in a heating coil 34, weight of the heating coil 34 is reduced by half, and since the product weight is reduced, damage on the top plate due to shock of the heating coil 34 when dropped accidentally can be prevented. Furthermore, material cost of the heating coil 34 can be reduced significantly and when the heating coil 34 is locally heated abnormally due to some reason, it is fused quickly to stop electrification thus enhancing safety.

Description

  The present invention relates to a heating cooker configured to prevent damage to a top plate on which a heated cooking container is placed.

  In recent years, induction heating cookers have become widespread as a safe and clean heat source that does not use fire and does not emit combustion gas. This induction heating cooker includes a heating coil for induction heating and various electronic components on a control circuit that supplies a high-frequency current to the heating coil in a controllable manner.

  The principle of the induction heating is that when an alternating current is passed through a conducting wire, magnetic lines are generated around it. When a substance that conducts electricity (usually metal) is placed near it, eddy currents flow in the metal under the influence of the changing magnetic field lines.

  Since metal normally has an electrical resistance, it is utilized that when a current flows through the metal, Joule heat corresponding to power = square of current x resistance is generated and the metal is heated.

  The actual induction heating cooker uses a mechanism in which when a high-frequency inverter power supply supplies a high-frequency current to the heating coil, a high-frequency magnetic field is generated in the heating coil, which is added to the pan and the pan (made of metal) directly generates heat.

  Here, when high-frequency current flows through the conductor constituting the heating coil, the current density is high on the surface of the conductor and decreases when it is separated from the surface, that is, the skin effect occurs, the resistance increases, and the temperature rises greatly. Therefore, there is a problem that efficiency is lowered.

  As a preventive measure, there is a method of increasing the surface area of the conductor by subdividing the conductor, and a heating coil is mainly formed by winding a plurality of thin enameled copper wires in a spiral shape to form a heating coil. (For example, refer to Patent Document 1).

  FIG. 6A is a partially broken perspective view showing the structure of a conventional induction heating cooker described in Patent Document 1, and FIG.

  In FIG. 6A, when a high-frequency current is passed from the high-frequency inverter 1 to the heating coil 2 provided on the lower side of the iron pan 5 that is the object to be heated, a high-frequency magnetic field 3 is generated from the heating coil 2, and the high-frequency magnetic field 3 As a result, an induced current 9 flows in the bottom of the iron pan 5 and the iron pan 5 is heated by the Joule heat. The heating coil 2 is wound in a spiral shape and is composed of a litz wire.

  As shown in FIG. 6B, the litz wire is constituted by twisting a plurality of 0.5 mm copper strands.

  In order to suppress resistance in a high frequency region, a conventional induction heating cooker uses a litz wire in which 19 copper strands having a diameter of 0.5 mm are twisted as a heating coil as described above. Then, a high-frequency current having a frequency of 20 kHz is passed through a 20-turn winding of the heating coil made of the litz wire to heat a cooked container such as an iron pan.

  Moreover, as a holding | maintenance structure of the heating coil of an induction heating cooking appliance, there exists what was set as the structure which supports a heating coil by a simple method (for example, refer patent document 2).

  FIG. 7 is a cross-sectional view of a main part of another conventional induction heating cooker described in Patent Document 2. As shown in FIG. 7, in another conventional induction heating cooker, a top plate 11 on which a pan or the like is placed is composed of a ceramic plate or the like.

  Below the top plate 11, a coil 12 for generating magnetic lines for induction heating of the pan is disposed. The coil 12 is fixed on the support 13. Below the support 13, an inverter board 14 is provided for supplying high-frequency current to the coil 12 and driving it. The inverter board 14 is held on the board support 15.

  The substrate support 15 has a plurality of support bosses 16 for holding the support 13. An elastic body 17 composed of a spring is inserted into a column formed in the center of the support boss 16. The holding portion 18 is a cylindrical shape that is integrally formed on the outer peripheral portion of the support 13 and opens downward, and is covered with the elastic body 17. The support 13 is held by these members.

  Further, the support 13 is provided with a plurality of pressing bosses 19 above the holding portion 18. The pressing boss 19 is pushed up by the elastic body 17 and hits the back surface of the top plate 11. With this configuration, the distance between the coil 12 and the top plate 11 is always kept constant.

  Further, the sliding distance A of the support 13 depends on the shape and the urging force of the elastic body 17 and should not be smaller than the minimum value of the gap B between the support lower surface 20 and the top surface of the electronic component. is there.

  By setting it as such a structure, the distance of a top plate and the coil 12 can be made constant without an assembly variation. That is, the distance between the cooked cooking container placed on the top plate and the coil 12 can be made constant, the conditions for induction heating of the cooked cooking container are stabilized, and power supply control to the coil 12 during heating is performed. The electrical performance such as can be stabilized.

  However, in the conventional configuration, for example, if the product is accidentally dropped in a packaged state, an impact is applied to the main body. Here, the support 13 that supports the coil 12 is held by an elastic body 17. Therefore, the elastic body 17 is compressed downward, and the support body 13 is simultaneously pushed downward and slides.

  At that time, the pressed support 13 is pushed down until it hits the top surface of the electronic component mounted on the inverter board 14. Therefore, stress is applied to the electronic component, and the inverter board 14 is also destroyed together with the electronic component.

  For this reason, in the conventional configuration, the minimum value of the gap B between the support lower surface 20 and the top surface of the electronic component is increased or the biasing force of the elastic body 17 is increased so that no stress is applied to the electronic component. ing. When the minimum value of the gap B is increased, it is impossible to mount parts with high density in the space in the main body, resulting in an increase in product height, and it is not possible to meet the demand for a compact and thin main body.

  On the other hand, when the urging force is increased by changing the material or shape of the elastic body 17, the pressure applied to the top plate 11 from the pressing boss 19 increases. Therefore, the impact applied to the top plate 11 when the product is dropped increases, and the possibility that the top plate 11 is destroyed increases.

  For this reason, there is a configuration in which the heating coil is supported by a simple method and is not easily broken even when subjected to an impact such as dropping (for example, see Patent Document 3).

FIG. 8 is a cross-sectional view of a main part of another conventional induction heating cooker described in Patent Document 3. As shown in FIG. 8, another conventional induction heating cooker includes a top plate 21 on which a cooking container is placed, a heating coil 22, an inverter board 23, a support 24, a board support 25 and an elastic body. 26.

  The heating coil 22 induction-heats the cooking container. The inverter board 23 mounts components and drives the heating coil 22. The support 24 is disposed above the inverter board 23 and supports the heating coil 22.

  Further, the support 24 is provided with a pressing boss 27 on the upper side, and is pressed against the top plate 21 with the pressing boss 27 interposed therebetween. The substrate support 25 has three or more support bosses 28 that hold the support 24 and holds the inverter substrate 23.

  The elastic body 26 is interposed between the support 24 and the support boss 28. The support body 24 is provided with a first sliding restriction portion 24a, and the support boss 28 is provided with a second sliding restriction portion 28a. The first sliding restricting portion 24a and the second sliding restricting portion 28a are in contact with each other, and the sliding distance of the support 24 is smaller than the minimum value of the gap between the lower surface 24b of the support 24 and the top surface 23a of the component. Limit to be smaller.

  As a result, even if the elastic body 26 is compressed and the support body 24 is pressed down, the support body 24 does not hit the parts on the inverter board 23. Get higher.

JP-A-10-321358 JP 09-312195 A International Publication No. 2006/022275

  However, in the conventional configuration, the support body 24 on which the heating coil 22 is placed is pressed against the top plate 21 by the elastic body 26 interposed between the support body 24 and the support boss 28. If the impact at the time of product drop is large for some reason, such as when the fall height becomes high, the heating coil 22 moves up and down and the impact applied to the top plate 21 becomes large and the top plate 11 is destroyed. The fear increases.

  In particular, since the heating coil 22 uses a litz wire obtained by twisting a plurality of enameled copper wires, the heating coil 22 is inevitably heavy and increases its inertia. There is a concern that the impact applied to the head will increase and the possibility that the top plate 21 will be destroyed increases.

  The present invention solves the above-described conventional problems, by reducing the weight of the heating coil, reducing the inertia of the heating coil, and reducing the impact when the product is dropped in the packaged state. The purpose is to prevent damage.

  In order to solve the above-mentioned conventional problems, a heating coil of the present invention and an induction heating cooker using the heating coil are provided with a top plate provided on an upper surface of a main body, and a cover on the top plate provided below the top plate. A substantially circular heating coil that heats the cooking container, a coil base that holds the heating coil, and a control unit that includes an inverter drive unit that drives the heating coil, and the like.

  Among these, the heating coil has a configuration in which a single aluminum or a composite aluminum conductor in which different metals are disposed around the aluminum conductor is wound in a spiral shape so as to form a disk.

  Further, a top plate provided on the upper surface of the main body, a substantially circular heating coil that is provided below the top plate and heats the cooked cooking container on the top plate, a coil base that holds the heating coil, And a control unit having an inverter driving unit for driving the heating coil, and the heating coil is formed by winding a copper clad aluminum lead wire in a spiral shape so as to form a disk shape.

  With the above configuration, the heating coil is formed of a single aluminum or a composite aluminum conductor or a copper clad aluminum conductor in which different metals are arranged around the aluminum conductor, so the weight can be reduced by half compared to a copper wire, By reducing the inertia of the heating coil to reduce the impact when the product is dropped, the top plate can be prevented from being damaged.

  In addition, the product weight can be reduced and the cost can be greatly reduced. Further, the induction heating cooker is provided with a safety device such as a temperature sensor so as not to become an abnormally high temperature when the heated cooking container is heated.

  In the unlikely event that this safety device fails, the heating coil will also rise as the temperature of the cooking container increases. In this case, the melting temperature of aluminum is lower than that of copper. Composite aluminum conductors or copper clad aluminum conductors with dissimilar metals around them are melted at a lower temperature than copper conductors, so power is cut off and heating of the cooked cooking container stops, improving safety To do.

  The heating coil of the present invention and the induction heating cooker using the heating coil use the heating coil by using a single aluminum member or a composite aluminum conductor or a copper clad aluminum conductor in which different metals are disposed around the aluminum conductor. Halves the product weight, and when the product is accidentally dropped, damage to the top plate due to the impact of the heating coil can be prevented.

  In addition, the material cost of the heating coil can be greatly reduced, and if it is abnormally heated locally for any reason, the heating coil can be blown quickly at a lower temperature than the copper conductor to stop energization, which is safe. It is possible to improve the performance.

Sectional drawing of the principal part of the induction heating cooking appliance using the heating coil in Embodiment 1 of this invention and the heating coil of the induction heating cooking appliance using the same The principal part expanded sectional view of the heating coil in Embodiment 1 of this invention and the heating coil of the induction heating cooking appliance which uses it The principal part expanded sectional view of the heating coil in Embodiment 1 of this invention and the heating coil of the induction heating cooking appliance which uses it The principal part top view of the induction heating cooking appliance using the heating coil in Embodiment 1 of this invention and the heating coil of the induction heating cooking appliance using the same Control block diagram of induction heating cooker using heating coil and heating coil of induction heating cooker using the same in embodiment 1 of the present invention (A) Partially broken perspective view showing a structure of a conventional induction heating cooker described in Patent Document 1 (b) Cross-sectional view of a main part of a conventional induction heating cooker described in Patent Document 1 Main part sectional drawing of the other conventional induction heating cooking appliance described in patent document 2 Main part sectional drawing of the other conventional induction heating cooking appliance described in patent document 3

  1st invention hold | maintains the top plate provided in the upper surface of the main body, the substantially circular heating coil which is provided under the top plate and heats the to-be-heated cooking container on the top plate, and the heating coil A coil base and a control unit having an inverter driving unit for driving the heating coil, and the heating coil has a disk shape of a single aluminum member or a composite aluminum conductor in which dissimilar metals are disposed around the aluminum conductor. Thus, it is formed by winding in a spiral shape.

  As a result, the weight can be halved compared to the copper wire, and the top plate can be prevented from being damaged by reducing the inertia of the heating coil and reducing the impact when the product is dropped. .

  2nd invention hold | maintains the top plate provided in the upper surface of the main body, the substantially circular heating coil which is provided under the top plate and heats the to-be-heated cooking container on the top plate, and the heating coil A coil base and a control unit having an inverter drive unit and the like for driving the heating coil are provided, and the heating coil is formed by winding a copper-clad aluminum lead wire in a spiral shape so as to form a disk shape. .

  As a result, the heating coil is formed of a single aluminum or a composite aluminum conductor or a copper clad aluminum conductor in which different metals are disposed around the aluminum conductor, so that the weight can be reduced by half compared to the copper wire. By reducing the inertia of the product and reducing the impact when the product is dropped, the top plate can be prevented from being damaged.

  In addition, the weight of the product can be reduced and the price per kg varies depending on the time, but since aluminum is about 1/4 to 1/3 that of copper, the cost can be greatly reduced.

  Further, when the heating coil is locally heated abnormally for any reason, the safety of aluminum is improved because the melting point of aluminum is lower than that of copper.

  According to a third aspect of the invention, in particular, in the second aspect of the invention, the copper clad aluminum conductor is subjected to insulation treatment on the outer periphery with a heat-resistant varnish or the like.

  As a result, the outer periphery of the copper-clad aluminum conductor is insulated with a heat-resistant varnish or the like, so that the periphery of the copper-clad aluminum conductor can be easily slipped, easily wound, improved in workability, and hardly damaged on the surface of the copper-clad aluminum conductor. Therefore, the conductor wire is rubbed to generate powder of the conductor wire, and there is no fear of adversely affecting other parts of the electrical component.

  In particular, the fourth invention is an induction heating cooker using the heating coil of the first or second invention.

  As a result, the operational effects of the first or second invention described above can be obtained, the product weight can be reduced, and the top plate can be prevented from being damaged by the impact of the heating coil when the product is accidentally dropped. become.

  Also, the material cost of the heating coil can be greatly reduced, and if it is abnormally heated locally for any reason, the heating coil can be blown quickly to stop energization and improve safety. Will be able to.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a main part of a heating coil and an induction heating cooker using the heating coil in the first embodiment of the present invention, and FIG. 2 is a heating coil and the use thereof in the first embodiment of the present invention. 3 is an enlarged cross-sectional view of the main part of the heating coil of the induction heating cooker, and FIG. 3 is an enlarged cross-sectional view of the main part of the heating coil and the heating coil of the induction heating cooker using the heating coil in the first embodiment of the present invention. .

  FIG. 4 is a plan view of the main part of the induction heating cooker using the heating coil and the heating coil of the induction heating cooker using the heating coil according to the first embodiment of the present invention, and FIG. 5 is the first embodiment of the present invention. It is a control block diagram of the induction heating cooking appliance of the heating coil in the form of and the induction heating cooking appliance using the same.

  As shown in FIGS. 1-5, the top | upper surface of the main body 31 is formed with the top plate 33 which mounts the to-be-heated cooking containers 32, such as a pan, and the operation part 33a (FIG. 4) is provided in the one part.

  A substantially circular heating coil 34 that heats the cooked container 32 and a control unit 36 that controls the operation of the heating coil 34 and an inverter unit 35 that supplies power are disposed inside the top plate 33. The unit 36 turns on and off the switching semiconductor of the inverter unit 35 to control the high-frequency oscillation of the inverter unit 35 and also controls the start and stop of the oscillation operation.

  The inverter unit 35 is one of frequency converters, and includes a power rectifier, a filter capacitor, a resonant capacitor, a switching semiconductor, etc., converts the commercial power source 37 into a high frequency current, and supplies the high frequency current to the heating coil 34. The heating coil 34 generates a high-frequency magnetic field in the vicinity of the heated cooking container 32 and heats the bottom of the heated cooking container 32.

  As shown in FIG. 2, the heating coil 34 is placed on a heat-resistant resin-based coil base 38, and the wire forming the heating coil 34 is centered on an aluminum 39a as shown in FIG. And a plurality of thin copper clad aluminum conductors 39 formed of a thin layer of copper 39b, and each outer periphery is subjected to insulation treatment 39c with a heat-resistant varnish or the like, and twisted ones are wound into a spiral shape. It is.

  About the heating coil comprised as mentioned above and the induction heating cooking appliance using the same, the operation | movement and an effect | action are demonstrated below.

  When the heated cooking container 32 such as a pan is placed on the top plate 33 positioned on the top surface of the main body 31 and the user operates the operation unit 33a to start heating under a predetermined condition, the control unit 36 Then, the inverter unit 35 is operated to supply a high frequency current to the heating coil 34, and the heating coil 34 generates a high frequency magnetic field in the vicinity of the cooked cooking container 32 to heat the bottom of the cooked cooking container 32. ing.

  And since the heating coil 34 is the copper clad aluminum conducting wire 39, most of it is occupied by the aluminum portion, and the weight can be reduced by half compared to the litz wire of the copper wire, and the inertia of the heating coil 34 is reduced, By reducing the impact when the product falls, damage to the top plate and the like can be prevented.

Here, the comparison between copper and aluminum will be described in detail. As for the conductivity, if copper is 100, aluminum has a resistance value slightly higher than that of aluminum 61, and the direct current resistance value per unit length is the same. However, the density of aluminum is 1.64 times that of copper, but the density is 8.96 g / cm3 for copper and 2.70 g / cm3 for aluminum. The weight of aluminum is about half that of copper. Also, although the price per kg varies depending on the time, since aluminum is about 1/4 to 1/3 that of copper, the cost can be greatly reduced.

  The melting point is 660 ° C. for aluminum and 1083 ° C. for copper, and the heat of fusion is 209 J / g for aluminum versus 397 J / g for aluminum. 1872.64 J / g.

  Thereby, in the unlikely event that the safety device of the induction heating cooker (not shown) fails, the heating coil 34 also increases in temperature as the temperature of the cooking container 32 increases. In this case, aluminum has a melting temperature lower than that of copper, and the copper clad aluminum lead wire 39 is melted at a lower temperature than the copper lead wire, so that energization is cut off and heating of the cooked cooking container 32 is stopped. Will improve.

  Since the outer periphery of the copper clad aluminum conductor 39 is insulated with a heat-resistant varnish or the like, the periphery of the copper clad aluminum conductor 39 is easily slipped and smoothly wound, improving the workability and improving the surface of the copper clad aluminum conductor 39. Since it is hard to be damaged, the conductor wire is rubbed and powder of the conductor wire is generated, and there is no fear of adversely affecting other parts of the electrical component.

  Furthermore, with aluminum alone, solderability is poor and terminal processing is difficult, but since copper is clad on the outer periphery of the aluminum conductor, soldering is possible and stable quality over time can be obtained. Become. Also, in terminal processing other than soldering such as fusing, the copper clad aluminum conductor wire 39 can obtain a stable quality in terms of electrical connection with the terminal, similar to the copper conductor wire, from an aluminum simple substance.

  The heating coil 34 using the copper clad aluminum conductor 39 has been described. However, the same performance can be obtained with a conductor of aluminum alone, a dissimilar metal clad aluminum conductor other than copper, or a metal plated aluminum conductor. It is done.

  As described above, the heating coil according to the present invention and the induction heating cooker using the heating coil use a copper clad aluminum lead wire for the heating coil, so that the weight of the heating coil is halved and the product weight is reduced. When the product falls, the top plate can be prevented from being damaged by the impact of the heating coil.

  Also, the material cost of the heating coil can be greatly reduced, and if it is abnormally heated locally for any reason, the heating coil can be blown quickly to stop energization and improve safety. Therefore, it is effective for applications such as cooking using induction heating.

2, 22, 34 Heating coil 11, 21, 33 Top plate 14, 23 Inverter board 32 Heated cooking container 35 Inverter part 36 Control part 38 Coil base 39 Copper clad aluminum conductor 39c Insulation treatment

Claims (4)

A top plate provided on an upper surface of the main body, a substantially circular heating coil provided below the top plate for heating the cooking container to be heated on the top plate, a coil base for holding the heating coil, and the heating And a control unit having an inverter drive unit for driving the coil, and the heating coil is formed by spirally winding a single aluminum or a composite aluminum conductor in which different metals are arranged around the aluminum conductor into a disk shape. A heating coil formed by winding. A top plate provided on an upper surface of the main body, a substantially circular heating coil provided below the top plate for heating the cooking container to be heated on the top plate, a coil base for holding the heating coil, and the heating And a control unit having an inverter driving unit for driving the coil, and the heating coil is formed by winding a copper clad aluminum conductor in a spiral shape so as to form a disk. The heating coil according to claim 2, wherein the copper clad aluminum conducting wire is insulated on the outer periphery with a heat-resistant varnish or the like. An induction heating cooker using the heating coil according to claim 1 or 2.