JP2012119245A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating cooker which improves heat efficiency by reducing heat loss in a simple construction obtained by providing a magnetic material layer whereas damage of a top plate caused by the magnetic material layer is inhibited.SOLUTION: The induction heating cooker can decrease high-frequency resistance caused by a proximity effect depending on synergy effect between space means 30 and a magnetic material layer, form compact induction heating coils 24 and decrease high-frequency resistance as long as highly improving processability thereby providing low-cost induction heating coils 24. Further, the induction heating cooker can significantly reduce electronic field leakage by arranging a top plate 23 and the induction heating coils 24 so as to be nearly attached firmly to each other, and damage to the top plate caused by the magnetic material of the induction heating coils 24 can be inhibited by protection means 31.

Description

  The present invention relates to an induction heating cooker, and more particularly to a configuration of an induction heating coil that reduces loss and improves thermal efficiency.

  Induction heating is performed by using electromagnetic induction. In recent years, induction heating cookers are becoming popular as a heating method for new cooking utensils using the induction heating.

  According to the above-described principle of induction heating, when an alternating current is passed through a conducting wire, a magnetic force line is generated around it and changing its strength. 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 usually has electric resistance, when current flows through the metal, it is a phenomenon in which Joule heat corresponding to power = square of current x resistance is generated and the metal is heated.

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

  Here, when a high-frequency current flows through the conductor constituting the induction heating coil, a phenomenon in which the current density is high on the surface of the conductor and decreases when leaving the surface, that is, a skin effect occurs, resistance increases, and temperature rises. There are problems such as an increase in efficiency and a decrease in efficiency.

  As a preventive measure, there is a method of increasing the surface area of the conductor by subdividing the conductor, and a mainstream is an induction heating coil formed by spirally winding a plurality of thin enameled wires into a spiral shape. Yes.

  However, Litz wire is thin because each wire to be formed is easily damaged by twisting or breaking for some reason, such as being caught during induction heating coil manufacturing, and requires careful handling. Each wire forming the litz wire has been subjected to an enamel treatment for insulation, resulting in an increase in cost.

  Therefore, in order to provide an induction heating coil that has the same loss as the conventional induction heating coil with a simple and easy construction method, and has a margin for cooling performance, etc., and as a result, to provide an inexpensive induction heating device, the induction heating device The structure which inserts a magnetic body between the spiral electric conductors with the induction heating coil for electric power was considered (for example, refer patent document 1).

  FIG. 5 shows a conventional induction heating coil for induction heating apparatus described in Patent Document 1. In FIG. As shown in FIG. 5, the electric conductor 1 is formed in a spiral shape, and the magnetic body 2 is inserted between the electric conductors 1 on the inner periphery of the electric conductor 1. In addition, a space is provided between the electric conductors 1 in the middle and outer peripheral portions.

  Generally, when a current flows in parallel to adjacent electrical conductors, a proximity effect is generated in which the current is less likely to flow due to the influence of a magnetic field generated from each electrical conductor. The proximity effect described above will be described in detail using a litz wire.

FIG. 6 is a schematic view of an electromagnetic environment around adjacent coils, showing a coil wire 3 of an electric conductor and a magnetic flux 4 generated from the coil wire 3. In FIG. 6, it is assumed that a current flows through the coil wire 3 from the front side to the other side.

  The distribution of the current of the coil wire 3 is biased in a direction away from the adjacent coil wire due to the magnetic flux 4 generated from the adjacent coil wires.

  The shading of the color of the coil wire 3 represents the current density, and the dark portion indicates that the current density is high. A series of phenomena that cause this current distribution bias is generally called a proximity effect. Due to this proximity effect, the resistance of the induction heating coil (especially, the high frequency resistance when a high frequency current is passed) increases, and the heat generation loss of the induction heating coil increases.

  Conventionally, in order to solve this problem, as shown in FIG. 5, by inserting a magnetic body 2 between the turns of the electric conductor 1, a magnetic field is generated when a current flows through the electric conductor 1. However, the magnetic flux acting on the magnetic body 2 provided between the turns of the electric conductor 1 can reduce the proximity effect, resulting in a reduction in the resistance of the induction heating coil and induction. The heat loss of the heating coil is reduced.

JP 2002-043044 A

  However, the conventional configuration has a problem that it is difficult to manufacture because the magnetic body 2 is inserted between the turns of the spiral electric conductor 1.

  In particular, it is difficult to process the magnetic body 2 into a spiral shape and insert it between the electrical conductors 1. For example, using the powdered magnetic body 2 to insert between the spiral electrical conductors 1 Since the magnetic body 2 is in the form of powder, it is difficult to form it uniformly due to its properties, and even if it can, it is difficult to maintain that state and it is extremely difficult to manufacture.

  In addition, it is difficult to maintain the dimension of the portion without the magnetic body 2, that is, only the space between the electric conductors 1 at a predetermined value. Furthermore, the magnetic body 2 is basically conductive, and it has been difficult to ensure insulation between the electrical conductors 2.

  The present invention solves the above-described conventional problems, and reduces the heat loss and increases the thermal efficiency with a simple configuration in which a magnetic layer is provided, and prevents damage to the top plate caused by the magnetic layer. With the goal.

  In order to solve the conventional problems, a top plate provided on an upper surface of a main body, a substantially circular induction heating coil provided below the top plate for heating a cooked cooking container on the top plate, A coil base that holds the induction heating coil; and a control unit that includes an inverter drive unit that drives the induction heating coil. The induction heating coil is made of a metal conductor such as copper or aluminum arranged in a horizontal direction. Insulating space means having a conductor wire wound in a spiral shape in a horizontal direction so as to form a disk and having a magnetic layer between adjacent conductor wires wound in a spiral shape The top plate and the induction heating coil are disposed so as to be in close contact with each other, and the top plate and the induction heating coil are disposed between the top plate and the induction heating coil. By the induction heating coil sides said induction heating coil rate, certain safeguards to prevent hurt a structure in which disposed.

  Thus, an insulating space means is provided to provide a space between the adjacent conductor wires wound in a spiral shape, and a magnetic layer is provided between the adjacent conductor wires wound in a spiral shape. Since the insulating space means is provided and spaced apart, the high frequency resistance generated by the proximity effect can be reduced by the synergistic effect of the space means and the magnetic layer.

  In particular, the reduction of the high frequency resistance caused by the proximity effect is a synergistic effect of the space means and the magnetic layer, and it is not necessary to increase the interval between adjacent conductor wires wound in a spiral shape provided by the space means. The thickness of the magnetic layer of magnetic material such as ferrite formed in the space means is not so much required, and as a result, the induction heating coil can be formed in a compact manner. As a result, the resistance of the induction heating coil is reduced and the induction heating coil is reduced. The heat loss of can be reduced.

  In addition, since the magnetic layer is not so thick, it can be easily formed on the surface by applying, printing, or transferring magnetic material such as ferrite, and the magnetic layer is thin, making it easy to bend. It can be easily wound into a spiral shape and formed into a coil shape, and the workability is greatly improved.

  And since it arrange | positions so that a top plate and the said induction heating coil may contact | adhere substantially, the distance of the to-be-heated cooking container and induction heating coil on a top plate will become short, and the coupling | bonding of a to-be-heated cooking container and an induction heating coil will be carried out. Since it becomes stronger, it becomes easier to heat and electromagnetic field leakage from the induction heating coil can be greatly reduced. Further, since the heat generated by the induction heating coil is transferred to the top plate, The amount that the top plate takes away can be reduced, and the thermal efficiency of the induction heating coil can be significantly improved by these synergistic effects.

  Moreover, since the protective means is provided so that the side surface of the induction heating coil of the top plate is not damaged by the induction heating coil, the surface of the side surface of the induction heating coil of the top plate itself or the induction heating applied to the surface is provided. Printing such as a display showing the position of the coil can be prevented from being rubbed and damaged by slight vibration of the induction heating coil when the device is moved or heated.

  In particular, the magnetic material forming the magnetic layer of the induction heating coil is extremely hard and harder than the glass used as the material of the top plate, so that the top plate surface is damaged even when the top plate is assembled in equipment assembly. Although there was a worry, the protection means can prevent the induction heating coil from being damaged by the magnetic material.

  The induction heating cooker of the present invention has a simple structure with a magnetic layer and good workability, reduces heat loss and increases thermal efficiency, and prevents damage to the top plate by the magnetic material of the induction heating coil. can do.

Sectional drawing of the principal part of the induction heating cooking appliance in Embodiment 1 of this invention The principal part expanded sectional view of the induction heating cooking appliance in Embodiment 1 of this invention The principal part top view of the induction heating cooking appliance in Embodiment 1 of this invention Control block diagram of induction heating cooker in Embodiment 1 of the present invention Sectional view of a conventional induction heating coil for induction heating device Schematic diagram of electromagnetic environment around neighboring coils

  According to a first aspect of the present invention, there is provided a top plate provided on an upper surface of a main body, a substantially circular induction heating coil provided below the top plate for heating a cooked cooking container on the top plate, and the induction heating coil. A coil base for holding, and a control unit having an inverter drive unit and the like for driving the induction heating coil, the induction heating coil includes conductor wires made of metal conductors such as copper and aluminum arranged in a horizontal direction. It is formed by spirally winding in the horizontal direction so as to form a disk shape, and an insulating space means having a magnetic layer is provided between the adjacent conductor wires wound in a spiral shape. The top plate and the induction heating coil are disposed so as to be in close contact with each other, and the induction of the top plate is between the top plate and the induction heating coil. By heat coil sides said induction heating coil, the protection means to prevent scratching is obtained by a structure in which disposed.

  Thus, an insulating space means is provided to provide a space between the adjacent conductor wires wound in a spiral shape, and a magnetic layer is provided between the adjacent conductor wires wound in a spiral shape. Since the insulating space means is provided and spaced apart, the high frequency resistance generated by the proximity effect can be reduced by the synergistic effect of the space means and the magnetic layer.

  In particular, the reduction of the high frequency resistance caused by the proximity effect is a synergistic effect of the space means and the magnetic layer, and it is not necessary to increase the interval between adjacent conductor wires wound in a spiral shape provided by the space means. The thickness of the magnetic layer of magnetic material such as ferrite formed on the magnetic layer is not required so much, and as a result, the induction heating coil can be formed compactly, resulting in a reduction in the resistance of the induction heating coil and induction heating. The heat loss of the coil can be reduced.

  In addition, since the thickness of the magnetic layer is not so much required, a powdered magnetic material such as ferrite can be easily formed on the surface by coating, printing, transfer, etc., and the thickness of the magnetic layer can be reduced. Since it is thin, it can be easily bent, and it can be easily wound into a spiral shape to form a coil shape, which greatly improves the workability.

  And since it arrange | positions so that a top plate and the said induction heating coil may contact | adhere substantially, the distance of the to-be-heated cooking container and induction heating coil on a top plate will become short, and the coupling | bonding of a to-be-heated cooking container and an induction heating coil will be carried out. Since it becomes stronger, it becomes easier to heat and electromagnetic field leakage from the induction heating coil can be greatly reduced. Further, since the heat generated by the induction heating coil is transferred to the top plate, The amount that the top plate takes away can be reduced, and the thermal efficiency of the induction heating coil can be significantly improved by these synergistic effects.

  In addition, since the protective means is provided so that the side surface of the induction heating coil of the top plate is not damaged by the induction heating coil, the surface of the side surface of the induction heating coil of the top plate itself or the induction heating coil applied to the surface thereof It is possible to prevent printing such as a display indicating the position from being rubbed and damaged by slight vibration of the induction heating coil when the device is moved or heated.

  In particular, the magnetic material forming the magnetic layer of the induction heating coil is extremely hard and harder than the glass used as the material of the top plate, so that the top plate surface is damaged even when the top plate is assembled in equipment assembly. Although there was a worry, the protection means can prevent the induction heating coil from being damaged by the magnetic material.

  Further, it is difficult to be affected by heat from the cooking container to be heated during baking, the induction heating coil can be protected, and the heat resistance of the induction heating coil can be improved.

In the second invention, in particular, the protection means of the first invention is formed of a material having low dielectric loss and high heat resistance such as mica or tetrafluoroethylene resin.

  As a result, the space means is formed by inserting a material having low dielectric loss and high heat resistance such as mica or tetrafluoroethylene resin between the conductor wires, thereby reducing loss due to leakage current between the conductor wires. become able to.

  In the third invention, in particular, the magnetic material layer of the space means of the first or second invention is formed on the surface by applying a magnetic material such as ferrite to a heat-resistant substrate such as a glass tape, printing, transfer or the like. It is configured.

  As a result, the magnetic layer is formed on the surface by applying a magnetic material such as ferrite to a heat-resistant substrate such as a glass tape, or by printing, transferring, etc. If the magnetic layer does not fall off even if cracks occur in the magnetic layer over time, the effect of the magnetic layer on the space means is stabilized.

  Further, since the magnetic layer is integrated with the space means, it is easy to handle, and it is easy to form a coil by winding it in a spiral shape, and the workability is greatly improved.

  In the fourth aspect of the invention, in particular, the conductor wire of any one of the first to third aspects of the invention is configured by subjecting the outer periphery to insulation treatment with a heat-resistant varnish or the like.

  And since the outer periphery of the conductor wire is insulated with a heat-resistant varnish or the like, the periphery of the conductor wire is easy to slip, it is easy to wind smoothly, the workability is improved, and the surface of the conductor wire is hard to be damaged. There is no need to worry about the conductive wire powder being rubbed and adversely affecting other electrical components.

  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 the main part of the induction heating cooker according to the first embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the main part of the induction heating cooker according to the first embodiment of the present invention, and FIG. The principal part top view of the induction heating cooking appliance in the 1st Embodiment of this invention, FIG. 4 is a control block diagram of the induction heating cooking appliance in the 1st Embodiment of this invention.

  As shown in FIGS. 1-4, the top | upper surface of the main body 21 is formed with the top plate 23 which mounts the to-be-heated cooking containers 22, such as a pan, The operation part 21a is provided in the part, Top plate 23 Inside, a substantially circular induction heating coil 24 for heating the cooked cooking container 22 and a control unit 26 for controlling the operation of the induction heating coil 24 and the inverter unit 25 for supplying power are arranged. 26 controls the high-frequency oscillation of the inverter unit 25 by turning on and off the switching semiconductor of the inverter unit 25 and also controls the start and stop of the oscillation operation.

  The inverter unit 25 is one of frequency converters and includes a power supply rectifier, a filter capacitor, a resonant capacitor, a switching semiconductor, and the like. The inverter unit 25 converts the commercial power supply 27 into a high frequency current, and supplies the high frequency current to the induction heating coil 24. The induction heating coil 24 generates a high-frequency magnetic field in the vicinity of the heated cooking container 22 and heats the bottom of the heated cooking container 22.

The induction heating coil 24 is placed on a heat-resistant resin-based coil base 28, and is a conductor wire using a litz wire that is insulated by a heat-resistant varnish on the outer periphery composed of a plurality of fine wires. 29 and a space means 30 having an insulating property and an adhesive property that provide an interval between adjacent lines are wound in a spiral shape so as to form a disk shape.

  This space means 30 is a semi-cured state in which a binder 30b obtained by mixing a magnetic material such as ferrite with a heat-resistant silicon varnish of a thermosetting resin having an insulating property as an adhesive component is applied to a glass heat-resistant tape-like substrate 30a. In this state, it has thermal self-bonding properties so that when it is heated after being applied to the adherend, it is cured by adhesion and the adherend (conductor wire 29 in the present invention) is fixed. is doing.

  Then, a magnetic layer is formed between adjacent conductor wires 29 by a binder 30b mixed with a magnetic material such as ferrite, and the magnetic layer has a magnetic material and an adhesive component. It is formed so as to be wrapped with an adhesive component so as to impart insulation to the magnetic layer.

  Further, the induction heating coil 24 is arranged so as to be in close contact with the top plate 23. The induction heating coil 24 and the heated heating container 24 are set as close as possible to the heated cooking container 22 placed on the top plate 23. The cooking container 22 is easily connected, and the side surface of the induction heating coil 24 of the top plate 23 is low in dielectric loss and heat resistant so as not to be damaged by the induction heating coil 24 between the top plate 23 and the induction heating coil 24. A protective means 31 made of mica having a high thickness and a small thickness is provided.

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

  When a heated cooking container 22 such as a pan is placed on the top plate 23 positioned on the top surface of the main body 21 and the user operates the operation unit 21a to start heating under a predetermined condition, the control unit 26 The inverter unit 25 is operated to supply a high frequency current to the induction heating coil 24. The induction heating coil 24 generates a high frequency magnetic field in the vicinity of the cooked cooking container 22 so as to heat the bottom of the cooked cooking container 22. It has become.

  Here, an insulating space means 30 is provided to provide a space between adjacent conductor wires 29 wound in a spiral shape, and a magnetic layer of magnetic material such as ferrite mixed in the binder 30b of the space means 30 Is arranged between the adjacent conductor wires 29 wound in a spiral shape, and the high frequency resistance generated by the proximity effect is reduced by the synergistic effect of the space between the conductor wires 29 by the space means 30 and the magnetic layer. it can.

  Particularly, the reduction of the high-frequency resistance caused by the proximity effect is a synergistic effect of the space means 30 and the magnetic layer, and there is no need to increase the interval between the adjacent conductor wires 29 wound in a spiral shape provided by the space means 30. Further, the thickness of the magnetic layer is not so much required, and as a result, the induction heating coil 24 can be formed compactly, the resistance of the induction heating coil 24 is reduced, and the heat loss of the induction heating coil 24 is reduced. Will be able to.

  In addition, since the magnetic layer is not so thick, it can be easily formed on the surface by applying, printing, or transferring magnetic material such as ferrite, and the magnetic layer is thin, making it easy to bend. It can be easily wound into a spiral shape and formed into a coil shape, and the workability is greatly improved.

And since it arrange | positions so that the top plate 23 and the induction heating coil 24 may contact | adhere substantially, the distance of the to-be-heated cooking container 22 and the induction heating coil 24 on the top plate 23 will become short, and the to-be-heated cooking container 22 and induction | guidance | derivation will be carried out. Since the coupling of the heating coil 24 is strengthened, heating is facilitated, electromagnetic field leakage from the induction heating coil 24 can be greatly reduced, and heat generated by the induction heating coil 24 is transferred to the top plate 23. Therefore, the amount that the top plate 23 takes away the heat from the cooking container 22 to be heated can be reduced, and the thermal efficiency of the induction heating coil 24 can be greatly improved by these synergistic effects.

  Further, since the protection means 31 is provided so that the side surface of the induction heating coil 24 of the top plate 23 is not damaged by the induction heating coil 24, the surface of the side surface of the induction heating coil 24 of the top plate 23 or the surface thereof is applied. It is possible to prevent printing such as a display indicating the position of the induction heating coil 24 from being rubbed and damaged by slight vibration of the induction heating coil 24 when the device is moved or heated.

  In particular, since the magnetic body forming the magnetic layer of the induction heating coil 24 has a very high hardness and is harder than glass used as the material of the top plate 23, the top plate is also mounted when the top plate 23 is assembled in the assembly of equipment. However, the protection means 31 can prevent the induction heating coil 24 from being damaged by the magnetic material.

  Moreover, it can become difficult to receive the influence of the heat from the to-be-heated cooking container 22 at the time of empty baking, the induction heating coil 24 can be protected, and the heat resistance of the induction heating coil 24 can be improved.

  Further, since the binder 30b is formed by applying a magnetic material such as ferrite on the surface of the base material 30a by printing, printing, transfer or the like, the base material 30a and the binder 30b of the magnetic layer are integrally formed, and there is a concern about misalignment. Even if cracks or the like occur in the magnetic material layer over time, the effect of the magnetic material layer on the space means 30 is stabilized if it does not fall off.

  Further, since the magnetic layer is integrated with the space means 30, it is easy to handle, and it is easy to form a coil by winding it in a spiral shape, and the workability is greatly improved.

  Furthermore, since the outer periphery of the conductor wire 29 is insulated with a heat-resistant varnish or the like, the periphery of the conductor wire 29 is easy to slide, and it is easy to wind smoothly and the workability is improved, and the surface of the conductor wire 29 is less likely to be damaged. The wire 29 is rubbed to generate the powder of the conductor wire 29, and there is no fear of adversely affecting other parts of the electrical component.

  The magnetic material of the binder 30b of the space means 30 is formed so as to be wrapped with an adhesive component so as to provide insulation to the magnetic layer. Therefore, even if the coating of the conductor wire 29 is somewhat damaged, the insulation is not It can be secured and safety is greatly improved.

  The binder 30b of the space means 30 is mixed with a magnetic material in a thermosetting resin so as to impart magnetism, thermal self-fusing property and insulating property at the same time. You may make it give sex later by another means.

  According to this, since heat self-bonding and insulating properties are provided later by another means, the number of steps is increased, but the processing process is simplified, and heat self-bonding and insulating properties are reliably obtained. Management can be simplified.

  Moreover, although the metal conductor used for the induction heating coil 24 has been described as a litz wire made up of a plurality of thin wires, this may be a ribbon-like conductor wire in which a metal conductor foil such as copper foil or aluminum foil is formed in a ribbon shape. Moreover, it is good also as a round-shaped strand with a large diameter, or a strand which this is crushed and the cross section has a flat shape.

According to this, one cross-sectional area of the strand corresponds to the cross-sectional area of a plurality of twisted enameled wires of Litz wire, and there is no need to worry about the multiple thin wires being caught or cut off. The workability can be greatly improved, and the wire becomes thick, so that the processing cost of the wire is greatly reduced and the cost can be reduced.

  Furthermore, the binder 30b, in which the magnetic material of the space means 30 is mixed with the heat-resistant silicon varnish of the thermosetting resin having an insulating property of the adhesive component, is applied to the glass heat-resistant tape-like base material 30a. This is a ribbon-shaped conductor in which a metallic conductor such as a copper foil or an aluminum foil is formed into a ribbon shape, or a round wire having a large diameter or a flat shape in which the cross section is flattened. By applying a binder mixed with a heat-resistant silicon varnish of a thermosetting resin having an insulating property as an adhesive component directly on this surface, the base material of the space means is not required and formed on this surface. May be.

  According to this, since a base material becomes unnecessary, it can be configured at low cost, the processing process can be simplified, and productivity is greatly improved.

  As described above, the induction heating coil according to the present invention has a simple configuration in which a magnetic layer is provided, reduces heat loss and increases thermal efficiency, and prevents damage to the top plate caused by the magnetic layer. Since an induction heating cooker can be provided, it can also be applied to industrial fields and the like using induction heating.

22 Heated cooking container 23 Top plate 24 Induction heating coil 28 Coil base 29 Conductor wire 30 Space means 30a Base material 31 Protection means

Claims (4)

A top plate provided on the upper surface of the main body, a substantially circular induction heating coil provided below the top plate for heating the cooked cooking container on the top plate, and a coil base for holding the induction heating coil; A control unit having an inverter driving unit for driving the induction heating coil, etc., and the induction heating coil has a disk-shaped conductor wire made of a metal conductor such as copper or aluminum arranged in a horizontal direction. In addition, an insulating space means having a magnetic layer is provided between the adjacent conductor wires wound in a spiral shape, and is provided with a space between the adjacent conductor wires. A plate and the induction heating coil are arranged so as to be in close contact with each other, and between the top plate and the induction heating coil, the side surface of the induction heating coil of the top plate The induced heating coil, an induction heating cooker which is disposed a protective means to prevent scratching. The induction heating cooker according to claim 1, wherein the protection means is formed of mica or tetrafluoroethylene resin. 3. The induction heating cooker according to claim 1, wherein the magnetic layer of the space means is configured to be formed on a surface by applying, printing, or transferring a magnetic material to a heat resistant substrate. The induction heating coil induction heating cooker according to any one of claims 1 to 3, wherein the conductor wire is insulated on an outer periphery.