JP2004047482A5 - - Google Patents

Description

Induction heating device

  The present invention relates to an induction heating device, and more particularly, to a heating coil with reduced loss due to high-frequency current.

  Conventionally, the only metal that can be heated by the induction heating apparatus is an iron-based metal having a high magnetic permeability. In particular, an induction heating cooker in which a heating device is applied to a cooker has recently been increasingly requested to use a copper pan or an aluminum pan in addition to an iron pan. By the way, in order to induction-heat a copper pan or an aluminum pan, since the magnetic permeability is low, a high frequency current of 40 to 100 kHz higher than 20 to 30 kHz suitable for an iron pan must be passed through the heating coil. However, the higher the frequency, the higher the effective resistance because the so-called skin effect causes high-frequency current to flow only near the surface of the conductor. Therefore, as a method for increasing the surface area and effectively reducing the resistance, a method has been used in which the diameter of the conducting wire is reduced, for example, several or several tens of conducting wires having a diameter of 0.1 mm or less are bundled. However, in this method, even if the effective resistance due to the skin effect can be reduced, the proximity action becomes remarkable due to the use of a large number of conducting wires, and the resistance cannot always be sufficiently reduced. The proximity action here refers to a phenomenon in which when current flows through a nearby conductor, it affects each other via a magnetic field and the current distribution is biased, resulting in an effective increase in resistance on the surface of the conductor. . The proximity action increases as the direction of the high-frequency current is aligned between the conductors and as the distance between the conductors decreases.

As a method of solving the above-mentioned problem, the coil conductor of the heating coil is formed into a multi-stage assembly structure that further aggregates the assembly wires bundled with the strands, and at least one assembly line is formed by knitting, The directions of the assembly lines are not uniform and are not in close contact with each other, whereby the proximity effect can be suppressed and the coil resistance against the high frequency current of the heating coil can be reduced (for example, see Patent Document 1).
Japanese Examined Patent Publication No.7-118377

  However, in the conventional configuration, the coil resistance of the heating coil with respect to the high frequency current can be reduced. However, in order to further improve the efficiency of induction heating, it is necessary to further reduce the coil resistance with respect to the high frequency current.

  The present invention solves the above-described conventional problems, and provides an induction heating device that reduces the influence of the proximity action, reduces the coil resistance to the high-frequency current of the heating coil, reduces the self-heating of the heating coil, and has good heating efficiency. The purpose is to do.

In order to solve the conventional problem, the induction heating apparatus of the present invention includes a heating coil formed by winding a coil conductor, and the coil conductor includes an element wire having an insulating layer around a conductor or the element wire. Insulation formed by twisting together bundled assembly wires, and a part or the whole of the outer periphery made of a fluororesin having a different melting point, and a low melting point fluororesin being made outside the fluororesin having a high melting point it is provided the body, the heating coil is adapted to stabilize the adjacent said insulator each other or the insulating member and the wire and the solid wear to shape by heating after previous SL wound coil wire, A high-frequency current of 40 to 100 kHz was passed through the heating coil to inductively heat an object to be heated such as copper or aluminum. With this configuration, when a heating coil is produced by winding with a coil conductor, since there is an insulator between the coil conductors, the spacing between the coil conductors is widened, thereby reducing the increase in high-frequency resistance due to the proximity action between the strands. In addition, the insulation strength between the coil conductors can be improved and the reliability can be improved.

According to the present invention, it is possible to obtain a heating coil in which the influence of the skin effect and the proximity action is reduced, and the coil resistance against high-frequency current is reduced. When heating a heated object of metal such as copper or aluminum, To provide an induction heating apparatus that has low self-heating of the heating coil, good heating efficiency, stabilizes the insulation of the heating coil, improves heating adhesiveness, ensures insulation reliability, and further achieves cost reduction. it can.

The invention according to claim 1 is provided with a heating coil formed by winding a coil conductor, and the coil conductor is formed by twisting together a strand in which an insulating layer is provided around a conductor or a bundle of bundles of the strands. An insulating body formed of a fluororesin having a different melting point and a fluororesin having a low melting point formed outside the fluororesin having a high melting point is provided on a part or the whole of the outer periphery of the heating coil; The coil conductor provided with the insulator is wound after being heated, and the adjacent insulators or the insulator and the strand are fixed to stabilize the shape, and the heating coil has a frequency of 40 to 100 kHz. When a heating coil is produced by winding with a coil conductor, the coil is heated by induction heating a heated object of metal such as copper or aluminum. Since there is an insulator between the conductors, the spacing between the coil conductors is widened. As a result, an increase in the high-frequency resistance due to the proximity action between the strands can be reduced, and the insulation strength between the coil conductors can be improved and reliability can be improved. In addition, the heat adhesiveness can be improved and the shape of the heating coil can be stabilized.

The invention according to claim 2 is provided with a heating coil formed by winding a coil conductor, and the coil conductor is formed by twisting together a strand in which an insulating layer is provided around a conductor or a bundle of bundles of the strands. Forming an upper assembly line, providing an insulator on at least a part or the whole of the outer periphery of the upper assembly line, and a multi-stage lap twist structure in which the upper assembly line provided with the insulator on the outer periphery is further twisted ; A high-frequency current of 40 to 100 kHz is supplied to the heating coil to inductively heat a metal object to be heated such as copper or aluminum, and the insulator is a sticky insulator having heating adhesiveness. When the coil conductor provided with the insulator is wound and then heated and melted and solidified, the adjacent insulators or the insulator and the strand are fixed to stabilize the shape. In the stickiness insulator uncured or semi-cured rubber, by a thermosetting resin or any of the impregnated woven or non-woven fabric, wider spacing between the upper wire assembly, and thus between the strands of the In addition to reducing the increase in high-frequency resistance due to the proximity action, when coiled wires are wound to produce a heating coil, the insulation strength between the coiled wires is improved, reliability is increased , and heat is applied to insulate the insulator. By fixing the body, the shape of the heating coil can be stably maintained .

The invention described in claim 3 reduces the volatile component before providing an insulator on the outer periphery of the upper assembly wire or / and the coil lead wire. Therefore, when heat is applied to the heating coil during use or between the insulators When heat is applied to the heating coil during bonding, the volatile components generated from the inside of the heating coil do not accumulate between the upper assembly wire and the insulator or between the coil conductor and the insulator, and the volatile component does not adhere to the heating coil. Deformation can be prevented.

In the invention according to claim 4 , in particular, the heating coil is configured to inductively heat a heated body by passing a high-frequency current through a heating coil formed by winding a coil conductor. By configuring the conductor portion volume to be 50% or less, the distance between the strands when viewed as the entire heating coil is widened, and an increase in resistance due to the proximity action can be suppressed.

In the invention according to claim 5 , in particular, when the diameter of the conductor portion of the strand becomes 0.1 mm or less, it becomes difficult to manufacture thickly the insulation layer of the strand itself and the cost becomes high. Alternatively, the insulation can be easily reinforced by providing an insulator on the outer periphery of the coil conductor, and the reliability can be improved and the cost can be reduced.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings, taking an induction heating cooker as an example of an induction heating device. A feature of the present embodiment is that a coil conductor is produced by assembling strands having different cross-sectional areas, and a heating coil is provided by winding the coil conductor. As described above, when a high frequency current of 40 to 100 kHz is passed through the heating coil in order to heat a heating body having a low magnetic permeability such as a copper pan or an aluminum pan, the effective resistance of the heating coil increases due to the so-called skin effect. Therefore, in order to reduce the effect of the skin effect, strands with a small cross-sectional area are used. However, when wires with a small cross-sectional area are used, the windings are dense, that is, the occupation ratio is improved and effective between the strands. As a result, the increase in resistance due to the proximity effect becomes significant. In the present invention, the skin effect is reduced by using many strands having a small cross-sectional area, and by mixing a strand having a small cross-sectional area and a strand having a large cross-sectional area, The distance is substantially increased, and an increase in resistance due to the proximity action can be suppressed, the high-frequency resistance of the heating coil can be substantially reduced, the self-heating of the heating coil can be reduced, and the heating efficiency can be improved. . Hereinafter, it demonstrates using drawing.

  First, a schematic configuration of the induction heating cooker will be described with reference to FIG. 1 is a main body constituting the outer shell of the induction heating cooker, 2 is a top plate provided on the main body 1, 3 is a heating coil produced by winding using a coil wire according to the present invention, and 4 is a heating coil 3 control. 5 is a heating body such as a pan placed on a heating section provided on the top plate 2 corresponding to the heating coil 3. In this configuration, when a high-frequency current is passed through the heating coil 3, a magnetic flux is generated, and the heating element 5 is heated by heat generation due to the eddy current loss of the magnetic flux.

  Hereinafter, the configuration of the coil conductor in the present embodiment will be described. FIG. 1 is a cross-sectional view of an assembly line of heating coils used in the induction heating cooker according to the first embodiment of the present invention. In FIG. 1, an assembly wire 6 is a mixture of a strand 7 having a small cross-sectional area, for example, a strand having a diameter of 0.05 mm, and a strand 8 having a large cross-sectional area, for example, a strand having a diameter of 0.1 mm. Are bundled or twisted together. In FIG. 1, in order to reduce the proximity action of the strand 7 having a small cross-sectional area used to reduce the skin effect, the strand 7 having a small cross-sectional area and the strand 8 having a large cross-sectional area are randomly mixed. It shows the state that was made to. Thereby, the effective space | interval between the strands 7 with a small cross-sectional area can be enlarged. As described above, if the strands 7 having a small cross-sectional area are necessarily interposed between the strands 8 having a large cross-sectional area so that the spacing between the strands 7 having a small cross-sectional area is effectively increased, the proximity action is achieved. Can be reduced. Further, it is more effective if the strands 7 having a small cross-sectional area and the strands 8 having a large cross-sectional area are not biased.

  The assembly line thus obtained is twisted several bundles as the first stage to form an upper assembly line, and if necessary, the upper assembly line is twisted into several bundles to form a higher order assembly line. When a heating coil is produced by winding a coil lead wire having a multi-stage lap twist structure in which the upper assembly wire is twisted a plurality of times in this way, the high frequency resistance of the heating coil increases due to the proximity action even when a high frequency current of 40 to 100 kHz is passed. It is possible to suppress this, reduce self-heating of the heating coil, and obtain a heating coil with good heating efficiency. That is, when the cross-sectional area is the same by adjusting the number of strands having a diameter of 0.05 mm and strands having a diameter of 0.1 mm, the high-frequency resistance is smaller for the strand having a diameter of 0.05 mm. Therefore, when a strand having a diameter of 0.05 mm and a strand having a diameter of 0.1 mm are mixed, a high-frequency current mainly flows through the strand having a diameter of 0.05 mm, and the strand having a diameter of 0.1 mm is not much. It stops flowing. Here, when a strand having a diameter of 0.1 mm enters between a strand having a diameter of 0.05 mm, the space between the diameter of 0.05 mm and 0.05 mm is expanded, and the high-frequency resistance of the heating coil is increased by a proximity action. Can be prevented.

  FIG. 3 is a sectional view of the assembly line of the heating coil showing another example used in the induction heating cooker according to the first embodiment of the present invention. In FIG. 3, the strand 7 having a small cross-sectional area is arranged around the strand 8 having a large cross-sectional area, for example, nine 0.05 mm strands are arranged around the 0.1 mm strand, and the assembly wires 9 are arranged. Are twisted together. Furthermore, the assembly line 9 is twisted to form an upper assembly line 10. By doing in this way, since the effective space | interval between the strands 7 with a small cross-sectional area with sufficient balance can be expanded, the increase in resistance by a proximity effect can be suppressed with sufficient balance. Further, if necessary, the upper assembly wire 10 is twisted to form an upper assembly wire, and the coil conductor having a multi-stage stranded structure can be obtained by repeating this process as necessary.

  Moreover, FIG. 4 is sectional drawing which shows the assembly line of the other heating coil used for the induction heating cooking appliance in the 1st Embodiment of this invention. In FIG. 4, the strand 7 having a small cross-sectional area is set as a twisted assembly wire 12, and the strand 8 having a large cross-sectional area is arranged around the twisted assembly wire 11, and these are twisted to form the upper assembly wire 13. . For example, in the figure, strands with a large cross-sectional area of 0.1 mm are combined from 4 wires to form an assembly wire, and 8 bundles of strands of 7 strands with a small cross-sectional area of 0.05 mm are twisted around it. Twisted and upper assembly line. By doing so, it is possible to widen the effective distance between the strands having a small cross-sectional area in a well-balanced manner, and thus it is possible to stably suppress an increase in the high-frequency resistance due to the proximity action.

  In the first embodiment, as shown in FIGS. 3 and 4, the strands having a small cross-sectional area are arranged around the strands having a large cross-sectional area. A strand having a large cross-sectional area may be disposed on the substrate. In short, a strand having a small cross-sectional area and a strand having a large cross-sectional area may be disposed in a balanced manner.

(Embodiment 2)
The present embodiment relates to a coil conductor having a multi-stage lap-twisted structure, which is configured by performing a plurality of twisting steps as necessary, by further twisting a plurality of assembly wires obtained by twisting thin strands. In addition, an insulator is disposed on at least a part of the coil conducting wire or the assembly wire, the effective distance between the wires is increased, and an increase in resistance due to the proximity action is suppressed. This will be described below with reference to the drawings.

  FIG. 5 is a cross-sectional view of the coil lead wire of the induction heating cooker in the second embodiment of the present invention. In the figure, seven bundles of bundled wires 14 in which 60 strands having a diameter of 0.05 mm, for example, are bundled, are twisted to form a higher bundle 15, and this bundle of upper bundles 15 is twisted in three stages. The coil conductor 16 has a twisted structure. Heat is applied to the coil conductor 16 to reduce volatile components of the coil conductor 16 itself, and then an insulator 17 is provided on at least a part of the outer periphery of the coil conductor 16. When the coil conductor 16 having this structure is wound to produce a heating coil, an insulator is present in at least a part between the coil conductors 16, so that the spacing between the coil conductors 16 is increased, and consequently the spacing between the strands. Therefore, an increase in high-frequency resistance due to the proximity action can be suppressed. In addition, when an insulator is provided on the entire coil conductor 16, the overall insulation strength between the coil conductors 16 increases when the coil conductor 16 is wound, and the reliability can be improved. Further, since the voltage difference between the turns of the coil conductor 16 is large, as a result, this method in which the insulator 17 is provided between the turns has high insulation reliability. Further, when the diameter of the strand becomes about 0.05 mm as in the present embodiment, it becomes difficult to increase the thickness of the insulating layer of the strand itself, resulting in an increase in cost. Therefore, this method is excellent in securing the insulation reliability and realizing the cost reduction particularly when the coil wire having a small diameter (0.1 mm or less) is used.

  Moreover, FIG. 6 is sectional drawing which shows the other coil conducting wire of the induction heating cooking appliance in this Embodiment. In FIG. 6, heat is applied to the upper set line 15 to reduce volatile components in the upper set line 15 itself, and then at least part of the outer periphery of the upper set line 15 is covered with an insulator 17. The upper assembly wire 17 covered with the insulator 17 is twisted into three bundles to form a coil conductor 18. In this configuration, since an insulator is present at least at a part between the upper set lines 15, the distance between the upper set lines 15 is increased, and as a result, the distance between the strands is increased, thereby suppressing an increase in resistance due to the proximity action. can do. In addition, if the coil conductor 18 is manufactured in a configuration in which an insulator is provided on the entire upper assembly line 15, since the insulator exists between the coil conductors 18 when wound, the overall insulation strength increases and reliability is increased. Can be increased.

  As a method for providing the coil conductor 16 with an insulator, a tape or a thread-like body may be wound around the coil conductor 16, or a film-like insulator may be sandwiched at the time of winding. Further, a method of applying a liquid substance and curing it may be used.

  As the insulator, a heat-resistant inorganic fiberglass, mica, an organic tape made of fluororesin, polyimide resin, polyamideimide resin, or the like is used. Of these, glass tape is suitable because it is inexpensive and has good workability. Further, the glass tape is suitable for impregnating the resin to the inside because the resin permeates when the heating coil is made and then the resin is impregnated to stabilize the shape of the heating coil device.

  As a method for omitting the resin impregnation step, a method using a self-bonding line shown in FIG. 7 is generally performed. That is, by producing a heating coil using a strand in which an insulating layer 20 is provided around the conductor 19 and a fusion layer 21 is provided outside the conductor 19, and then the fusion layer 21 is melted and solidified by heating, This is a method in which the strands are fixed and the shape of the heating coil can be stably maintained.

  In this embodiment, since an insulator is provided on the outer periphery of the coil conductor or the upper assembly wire, by using this insulator, the shape of the heating coil can be stabilized without using the wire fusion layer 21. Can be held. That is, a thermoplastic resin such as polyamide resin, polyamideimide resin, polyester resin, or fluororesin is used as an insulator, and the thermoplastic resin is heated and melted in the middle of manufacturing the heating coil or after winding the heating coil. By solidifying and solidifying, the insulator and the insulator or the insulator and the strand can be fixed and the shape of the heating coil can be stabilized. Further, the heat adhesiveness can be improved by forming the insulator from two types of resins having different melting points and forming the resin having a low melting point outside the resin having a high melting point. For example, when a fluororesin is used for the insulator, a fluororesin having a low melting point (ETFE or FEP) is used on the outside, and a fluororesin having a high melting point (PFA) is used on the inside, the stable insulation and heat adhesion can be improved. Can do.

  Furthermore, using an uncured or semi-cured rubber or a thermosetting resin as an insulator, and heating and solidifying in the middle of the production of the heating coil or after winding the heating coil, the insulator and the insulator or An insulator and a strand can be fixed and the shape of a heating coil can be stabilized. As the rubber, silicon-based, fluorine-based, etc. are used, and as the thermal effect resin, epoxy resin, unsaturated polyester resin, phenol resin, or the like is used.

  In addition, the shape of the heating coil is stabilized by applying or impregnating a woven or non-woven fabric with a non-cured or semi-cured rubber or resin as an insulator, in particular a semi-cured rubber or resin, and heat curing as described above. be able to. In particular, when a tape-shaped woven fabric or non-woven fabric is used, a part or the whole of the outer periphery of the assembly wire or the coil conductor can be easily wound, so that handling is easy and a stable insulating layer can be provided. In general, the same kind of rubber or resin as described above is used.

  Further, as shown in FIG. 8, after heat is applied in advance to reduce volatile components in the coil conductor 16 itself, an insulator 17 is provided on the outer periphery of the coil conductor 16 and an adhesive layer 22 is provided on the outer side thereof. It may be. The adhesive layer here includes a fusion layer. By heating the coil conductor 16 having this configuration after being wound, the coil conductor and the coil conductor are fixed to each other, and a heating coil having a stable shape can be obtained.

  In addition, a heat shrinkable tape may be used. That is, the heat shrink tape is wound around the upper assembly wire or / and the coil conductor, and then the tape is contracted by heating to tighten the upper assembly wire or / and the coil conductor, thereby making the heating coil stable. .

  With the above-described configuration, the shape of the heating coil can be stabilized without using a fusion layer of strands. However, if the fusion layer is not used, the distance between the strands becomes small, and there may be a problem of increased resistance due to the proximity action. In this case, the insulating thickness corresponding to the fusion layer may be increased. Thereby, the manufacturing process of a strand can be simplified and a price can be reduced.

  Note that the heat resistance of the insulating material may be selected from the heat-resistant categories required by design.

  As described above, according to the present embodiment, an increase in high-frequency resistance due to the proximity action can be suppressed, and insulation performance can be improved and reliability can be increased. Furthermore, by using an insulating configuration having adhesiveness, the coil shape can be stabilized. In addition, after reducing the volatile components of the coil conductor and upper assembly wire with heat, an insulator is provided on the outer periphery of the coil conductor and upper assembly wire, so if the heating coil is heated during use or between the insulators When heat is applied to the heating coil during bonding, the volatile components generated from the inside of the heating coil do not accumulate between the upper assembly wire and the insulator or between the coil conductor and the insulator, and the volatile component does not adhere to the heating coil. Deformation can be prevented.

  As described in the first and second embodiments, in order to suppress an increase in the high-frequency resistance due to the proximity action, the cross-sectional area of the strands is increased, or an insulator is provided on the upper assembly line or the coil conductor. It is effective to provide it. Therefore, the influence of the proximity effect on the entire heating coil was examined by experiments such as changing the cross-sectional area of the wire or changing the thickness and amount of the insulator. As a result, when the insulator is wound around the outer periphery of the heating coil, the insulating layer portion of the strand is not crossed in the cross-sectional area of the insulator not including the outer peripheral insulator, that is, the total space cross-sectional area occupied as the heating coil. If the configuration is such that the volume of the conductor portion to be excluded does not exceed 50%, an increase in the high-frequency resistance due to the proximity action can be suppressed, and if this ratio exceeds 50%, the high-frequency resistance due to the proximity action increases remarkably. Obtained. Thereby, the effect that it becomes easy to design in consideration of proximity | contact effect is acquired.

  The effects of the first and second embodiments are particularly effective when the object to be heated is induction-heated with a high frequency current of 40 to 100 kHz such as a copper pan or an aluminum pan.

  In addition, although this Embodiment demonstrated by the induction heating cooking appliance as an example of an induction heating apparatus, the same effect is acquired also in other various induction heating apparatuses.

  As described above, the induction heating device according to the present invention can reduce the skin effect and proximity effect of the high-frequency current in the heating coil, reduce the coil resistance against the high-frequency current, and improve the insulation of the heating coil. It is possible to stabilize and improve the heat adhesiveness to ensure the reliability of insulation and to further reduce the cost, so especially when induction heating the heated object with a high frequency current of 40 to 100 kHz such as a copper pan or an aluminum pan. It is valid.

Sectional drawing of the assembly line of the heating coil used for the induction heating cooking appliance in the 1st Embodiment of this invention Cross sectional view of the induction heating cooker Sectional drawing of the assembly line in the other example of the heating coil used for the induction heating cooking appliance Sectional drawing of the assembly line in the other example of the heating coil used for the induction heating cooking appliance Sectional drawing of the assembly line of the heating coil used for the induction heating cooking appliance in the 2nd Embodiment of this invention Sectional drawing of the assembly line in the other example of the heating coil used for the induction heating cooking appliance Cross-sectional view of wire Sectional drawing of the assembly line of the other example of the heating coil used for the induction heating cooking appliance in the 2nd Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Heating coil 6, 9, 11, 12, 14 Assembly line 7 Element wire with small cross-sectional area 8 Element wire with large cross-sectional area 10, 13, 15 Upper assembly line 16, 18 Coil conductor 17 Insulator 22 Adhesive layer (adhesion part) )

Claims (5)

A heating coil formed by winding a coil conductor, and the coil conductor is formed by twisting an element wire having an insulating layer around a conductor or a bundle of bundles of the element wires, part or whole consists of different melting points fluororesin, and low melting point fluorine resin is formed on the outside of the high melting point fluoropolymer insulator provided comprising, the heating coil is pre SL wound after the coil wire By heating, the adjacent insulators or the insulator and the strands are fixed to stabilize the shape, and a high frequency current of 40 to 100 kHz is passed through the heating coil to form a metal such as copper or aluminum. An induction heating device configured to inductively heat an object to be heated. A heating coil formed by winding a coil conductor is provided, and the coil conductor forms an upper assembly wire by twisting together an element wire provided with an insulating layer around a conductor or an assembly wire bundled with the element wire, A multistage lap twist structure is formed by providing an insulator on a part or the whole of the outer periphery of the upper assembly wire, and further twisting the upper assembly wire provided with the insulator on the outer periphery. by applying a current to the induction heating the heated body of metal such as copper or aluminum, the insulator is fixed insulator having heat adhesive property, the heating coil, the coil which the insulator is provided The conductor is wound and heated to melt and solidify, thereby adhering adjacent insulators or the insulator and the element wire to stabilize the shape, and the adhesive insulator is Curing or semi-cured rubber, a thermosetting resin or any of the impregnated woven or non-woven induction heating device. Before the insulator is provided on the outer periphery of the upper assembly wire or / and the coil conductor, heat is applied to the upper assembly wire or / and the coil conductor itself, and the upper assembly wire or / and the coil conductor itself has volatilization. induction heating apparatus according to claim 1 or 2, the insulator is provided after reducing component. The induction heating device according to any one of claims 1 to 3 , wherein the heating coil is configured such that a conductor part volume of the strand is 50% or less with respect to a total space volume. The induction heating apparatus according to any one of claims 1 to 4 , wherein an element wire having a conductor portion diameter of 0.1 mm or less is used for at least a part of the coil conductor.