JP5256008B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that heats an object to be heated such as a pan on a top plate using induction heating by a heating coil as a heat source in a kitchen or the like of a general household, and particularly relates to a heating coil.

  The heating coil of a conventional induction heating cooker has a bundle of litz wires formed by bundling together a plurality of conductor wires coated with an insulating layer such as enameled wire, and twisting this set wire together. A plurality of steps are wound around the circumference and formed into a disk shape.

  A resin coil base that holds this heating coil by bonding or screwing via a resin component is disposed below the top plate, and high frequency power is supplied to the heating coil to be heated and placed on the top plate. Inductive heating of copper and aluminum pans as well as iron, which is a product.

  When induction heating an iron pan, high frequency power of 20 to 40 kHz is supplied to the heating coil. However, when heating a copper or aluminum pan or the like, the heating coil has a frequency of 40 to 100 kHz higher than the above frequency. Supply high frequency power.

  When such a high-frequency power is supplied to the heating coil, the current density in the cross-sectional area of the conductor flows only to the outer periphery of the conductor due to the so-called skin effect, and the effective resistance value rises. The diameter is narrowed and many are bundled and twisted together.

  A plurality of conductor wires covered with an insulating layer are bundled to form an assembly wire, and the assembly wire is twisted to form a coil conductor, which is wound in a plurality of stages on a substantially identical circumference to form a disk. In a heating coil that is molded and configured to heat not only iron, but also copper and aluminum pans, etc., a part of or the entire outer periphery of the coil conductor wire is a fluoropolymer having a high melting point. It constitutes a PFA insulator of a fluoroalkyl vinyl ether copolymer, and on the outside thereof, a fluororesin having a low melting point is ETFE of tetrafluoroethylene / ethylene copolymer or FEP of tetrafluoroethylene / hexafluoropropylene copolymer. After forming the insulator into multiple layers on the same circumference and forming it into a disk shape, it is heated to form the outermost coil conductor. There has been proposed one that melts and solidifies ETFE or FEP, which is a fluororesin having a low melting point, and fixes adjacent insulators of the coil conductors to stabilize the shape of the heating coil (for example, see Patent Document 1). .

JP 2004-47482 A

  However, a heating coil in which an insulator made of two types of resin, that is, a fluororesin PFA having a high melting point and a ETFE or FEP having a low melting point is provided on the outer periphery of the coil conductor in the above-described prior art, is a fluororesin having a low melting point. Since ETFE or FEP is non-tacky, it is impossible to bond to the coil base with an adhesive when trying to hold it on the coil base. It was necessary to use a fixing method.

  Therefore, the number of parts increases and the fixing work is troublesome, which is expensive.

  In addition, if the heating coil and the coil base are not completely fixed due to variations in work when the heating coil is held on the coil base, the positional relationship between the heating coil and the object to be heated will vary, and the heating efficiency will deteriorate. There was a problem that the heating coil vibrated and abnormal noise was generated.

  The present invention solves the above-mentioned conventional problems, and the heating coil and the coil base are securely fixed, and by obtaining a heating coil with excellent insulation and good heating efficiency, the quality is stable and reliable. An object is to provide a high induction heating cooker.

The present invention has been made to solve the above problems, and in an induction heating cooker that heats an object to be heated by supplying high-frequency power to a heating coil held by a coil base, the heating coil is insulated. A PFA of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, which is a fluororesin having a high melting point, on the outer periphery of an assembly wire formed by twisting together a conductor wire coated with a layer or a conductive wire bundled with the wire configured insulating layer is provided, it is further composed of a coil conductor that wound gap tape-welded layer of the PPS of melting point than PFA lower polyphenylenesulfide resin spirally on the outer periphery, wound the coil wire and post-heating, the welding layer each other adjacent the PPS is melted and solidified, thereby stabilizing the shape of the heating coil The coil base and the welding layer made by the PPS bonded with silicone adhesive, has a structure for holding the heating coil to fit inside the rib provided in the center portion and the outermost portion of the coil base Is.

  Since the induction heating cooker of the present invention is configured as described above, it is possible to obtain a stable heating coil with a reliable heating coil and coil base, excellent insulation, and good quality in heating efficiency. it can.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 is a longitudinal sectional view of an essential part of an induction heating cooker showing Embodiment 1, FIG. 2 is a perspective view showing the configuration of a heating coil and a coil base, FIG. 3 is a sectional view of a coil conductor, and FIG. FIG. 5 is a sectional view of the heating coil and the coil base.

  1 and 2, the heating coil 3 is wound in a disk shape by winding a plurality of stages on substantially the same circumference, and is held by a coil base 4 made of PPS of polyphenylene sulfide resin as an insulator. It is provided below the top plate 2.

  A heated object 1 such as a pan is placed on a top plate 2 and is induction-heated by supplying high-frequency power to the heating coil 3 from an inverter circuit (not shown).

  The heating coil 3 is mounted so as to be fitted inside the rib 5 provided in the central portion and the outermost peripheral portion of the coil base 4.

  A magnetic body 6 such as ferrite is provided on the lower side of the coil base 4 so that the magnetic flux generated from the heating coil 3 spreads below the coil base 4 and erroneously heats nearby metals and electronic components. This prevents the electronic components from being affected by noise caused by magnetic lines of force.

  The coil base 4 on which the heating coil 3 is mounted is urged in the direction of the top plate 2 by a plurality of springs (not shown), and the heating coil 3 is configured to be substantially parallel to the top plate 2.

  3 and 4, the coil conductor 7 constituting the heating coil 3 is formed by bundling a plurality of conductor wires having a diameter of, for example, 0.05 mm, which are insulated with enamel or the like, and twisting the bundled conductors together. An insulating layer composed of a PFA (melting point: 310 ° C.) of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, which is a fluororesin having a high melting point and an excellent insulating property, constituting the wire 8. 9 is formed by extrusion molding, and further, a tape-like weld having a thickness of about 0.01 mm and a width of about 3 mm made of polyphenylene sulfide resin PPS (melting point: 280 ° C.) having a low melting point on the outside of the insulating layer 9 The layer 10 is wound in a spiral shape with a constant gap at a winding pitch of about 6 mm in the length direction of the coil conductor 7.

  Note that the assembly wire 8 of the coil conductor 7 may not be a bundle of a plurality of conductor wires insulated with enamel or the like.

  When the heating coil 3 is manufactured, the coil conductor 7 is wound in a plurality of stages on substantially the same circumference, formed into a disk shape, and then heated to form a tape-like welding layer 10 made of PPS having a low melting point. By melting and solidifying, the welding layers 10 of the adjacent coil conductors 7 are fixed to each other, thereby stabilizing the shape of the heating coil.

  At this time, the insulating layer 9 made of fluororesin PFA having a melting point higher than that of the PPS welding layer 10 inside the welding layer 10 can obtain a stable and highly reliable insulating property without deformation. .

  The heating coil 3 having a stabilized shape is fitted between the rib 5 at the center of the coil base 4 and the rib 5 at the outermost periphery of the coil base 4 as shown in FIG. The welding layer 10 and the coil base 4 are fixed and held by bonding them with an adhesive 12 such as a silicon adhesive. Note that PPS, which is a polyphenylene sulfide resin, has tackiness unlike a non-tacky fluororesin, and can be bonded by the adhesive 12.

  The welding layer 10 has a tape width of about 3 mm. However, if the tape width is too wide, for example, when the coil conductor 7 is formed into the heating coil 3 with a width of 6 mm, the heating coil 3 is processed. The tape width is preferably 4 mm or less so that the tape may be peeled off during the process.

  Further, as the winding pitch of the welding layer 10 is narrower, the area of the fixing portion is increased, so that the fixing strength is increased. However, since the work time for winding the welding layer 10 is increased, the mass productivity is inferior and the cost is increased. On the other hand, if the winding pitch is too wide, for example, if 9 mm, the adhesion strength between the welded layers 10 of the adjacent coil conductors 7 and the adhesive strength between the heating coil 3 and the coil base 4 may be insufficient, so the winding pitch is 9 mm or less. It is desirable to make it.

  As described above, the cost can be reduced by adopting a simple configuration in which the welding layer 10 and the coil base 4, which are formed of PPS on the outer periphery of the coil conductor 7, are bonded with the adhesive 12.

  On the other hand, in the case where a fluororesin insulator is provided on the outer periphery of the conventional coil conductor 7, the fluororesin has non-adhesiveness. Therefore, when the heating coil 3 is to be mounted on the coil base 4 as it is. Adhesion with an adhesive is impossible. Therefore, if a fixing method using screws is used with resin parts or the like, the work is troublesome and the number of parts increases, resulting in high costs.

  In addition, since the coil conductor 7 can be securely fixed to the coil base 4 by bonding, the positional relationship between the heating coil and the object to be heated varies, and the heating efficiency deteriorates. It is possible to eliminate the occurrence of abnormal noise due to vibration.

  A second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a cross-sectional view of the coil conductor of the second embodiment, and FIG. 7 is a perspective view of the coil conductor.

  The difference from the first embodiment is that, in the first embodiment, the tape-like welded layer 10 made of PPS is wound around the outer periphery of the insulating layer 9 of the coil conductor 7, whereas in this embodiment, the insulation is made. The point is that a PPS welding layer 10 is provided outside the layer 9 by extrusion molding.

  Thus, by covering the outer periphery of the coil conductor 7 with the welding layer 10 by extrusion molding, the outer side of the insulating layer 9 is tape-shaped on the outer side of the insulating layer 9 when the welding layers 10 of the adjacent coil conductors 7 are heated and fixed. Since the area of the part to which it adheres increases compared with what wound the welding layer 10 of this, it can strengthen.

  Similarly, when the heating coil 3 is bonded to the coil base 4, since the area of the bonding portion increases, the bonding strength can be increased.

  Moreover, since the welding layer 10 can be formed by extrusion, the working time can be shortened as compared with tape winding.

It is a principal part longitudinal cross-sectional view of the induction heating cooking appliance which shows Example 1. FIG. It is a perspective view which shows the structure of the heating coil of Example 1, and a coil base. FIG. 3 is a cross-sectional view of a coil lead wire of Example 1. FIG. 3 is a perspective view of a coil lead wire according to the first embodiment. It is sectional drawing of the heating coil and coil base of Example 1. FIG. 6 is a cross-sectional view of a coil conductor showing Example 2. It is a perspective view of the coil conducting wire of Example 2.

Explanation of symbols

1 Heated object 3 Heating coil 4 Coil base 7 Coil conductor 8 Assembly wire 9 Insulating layer 10 Welding layer 12 Adhesive

Claims (2)

In an induction heating cooker that heats an object to be heated by supplying high-frequency power to a heating coil held by a coil base,
The heating coil is made of tetrafluoroethylene / perfluoroalkyl vinyl ether which is a fluororesin having a high melting point on the outer periphery of an assembly wire formed by twisting a conductor wire coated with an insulating layer or a conductive wire bundled with the wire. copolymers insulating layer made of a PFA of provided, consists further in tape-like coil conductor was wound gap welding layer spiral of PPS having a low melting point than PFA polyphenylenesulfide resin on the outer periphery thereof,
After winding the coil wire, the welding layer each other of the PPS adjacent heated to melt and solidified, thereby stabilizing the shape of the heating coil, the coil base and the welding layer composed of the PPS An induction heating cooker configured to be bonded with a silicon adhesive and to hold the heating coil so as to be fitted inside ribs provided at a central portion and an outermost peripheral portion of the coil base . The induction heating cooker according to claim 1,
The induction heating cooker, wherein the welding layer made of the PPS is a tape having a width of 4 mm or less and a gap wound in a spiral shape with a winding pitch of 9 mm or less.

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