JP2010257891A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker capable of increasing a heating amount generated in a heating object and moreover capable of minimizing unevenness of the heating amount of a pan as much as possible. <P>SOLUTION: The induction heating cooker includes an inner-side coil wound around in a planar shape and an outer-side coil arranged around it, and at least one temperature sensor arranged between the inner-side coil and the outer-side coil. Either of the inner-side coil or the outer-side coil has a circular shape, and the other has a non-circular shape, and the inner-side coil and the outer-side coil come near at least partly, and the temperature sensor is arranged at a place where the inner-side coil and the outer-side coil are separated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an induction heating cooker having a plurality of induction heating coils.

  Induction heating cookers such as so-called IH cooking heaters produce eddy currents in cooking utensils such as pots made of electrical conductors by an alternating magnetic field generated when an alternating current of several tens of kHz is applied to a heating coil wound in a flat shape. It is formed and the cooking utensil itself is heated.

  A conventional induction heating apparatus having a plurality of induction heating coils is described in Patent Document 1, for example. The induction heating apparatus shown in FIG. 2 of Patent Document 1 has a first (inner) heating coil and a second (outer) heating coil arranged concentrically around the heating coil. Both the first (inner) and second (outer) heating coils have a circular shape, and a space having the same width in the circumferential direction between the first (inner) and second (outer) heating coils. The thermistor for detecting the temperature of the back surface of the top plate is disposed between the heating coils.

  Another conventional induction heating apparatus is disclosed in Patent Document 2, and the induction heating apparatus shown in FIG. 5 has a rectangular outer peripheral heating coil for a cooking plate and a circular inner peripheral heating coil for a pan. And the some pan detection apparatus is arrange | positioned in the center of an inner peripheral side heating coil, and the outer side of an outer peripheral side heating coil.

JP 2004-214217 A Japanese Examined Patent Publication No. 2-45313

  In general, in order to maximize the Joule heat generated when a heated object such as a pan is induction-heated by a heating coil, it is preferable to increase the area occupation ratio of the heating coil with respect to the opposed heated object as much as possible. However, according to the invention described in Patent Document 1, since both the first (inner side) and second (outer side) heating coils have a circular shape, the heating coil has the same width in the circumferential direction between these heating coils. An extending space is formed. That is, the heat generation efficiency of the pan in the space between these heating coils cannot be obtained as much Joule heat as the heat generation efficiency of the pan above the heating coil, and the heat generation amount of the pan varies in the radial direction (non-uniformity). Tend to be uniform).

  Moreover, in the induction heating apparatus described in Patent Document 2, a substantially wide space is provided between the outer and inner heating coils, and no pan detector is disposed in the space. . In Patent Document 2, it is described that the outer peripheral side heating coil is driven only when all of the pan detecting devices arranged on the outer side thereof detect the cooking plate, and Joule heat generated in the pan by the heating coil is described. In order to maximize the above, there is no mention of increasing the area occupation ratio of the heating coil as much as possible.

  Accordingly, the present invention has been made to solve the above problems, and is arranged between the inner coil wound in a planar shape and the outer coil arranged around the inner coil, and between the inner coil and the outer coil. At least one temperature sensor, wherein one of the inner coil and the outer coil has a circular shape, the other has a non-circular shape, and the inner coil and the outer coil are at least partially in proximity. The temperature sensor is arranged where the inner coil and the outer coil are separated from each other.

  According to the present invention, the area occupation ratio of the plurality of induction heating coils facing the heated body is increased as much as possible to increase the amount of heat generated in the heated body, and the variation in the radial direction of the amount of heat generated in the pan can be as much as possible. Can be small.

It is a perspective view showing the whole induction heating cooking appliance 1 concerning the present invention roughly. It is a bottom view when the induction heating part by Embodiment 1 is seen from the bottom. It is a bottom view when the induction heating part by a prior art is seen from the bottom. It is a bottom view when the induction heating part by Embodiment 2 is seen from the bottom. It is a bottom view when the induction heating part by Embodiment 3 is seen from the bottom. It is a bottom view when the induction heating part by Embodiment 4 is seen from the bottom. It is a bottom view when the induction heating part by Embodiment 5 is seen from the bottom. It is a bottom view when the induction heating part by Embodiment 6 is seen from the bottom. It is a bottom view when the induction heating part by the modification of Embodiment 1-6 is seen from the bottom.

  Embodiments of an induction heating cooker according to the present invention will be described below with reference to the accompanying drawings. In the accompanying drawings, the same components are referred to by the same reference numerals.

Embodiment 1 FIG.
The first embodiment of the induction heating cooker according to the present invention will be described in detail below with reference to FIGS. FIG. 1 is a perspective view schematically illustrating the entire induction heating cooker 1 according to the present invention. The induction heating cooker 1 shown in FIG. 1 generally includes a housing 7, a top plate 8 disposed thereon, an operation unit 9 for a user to adjust heating capability, and an induction heating unit 10. . The induction heating cooker 1 includes a high frequency power source (not shown) for supplying a high frequency current to the induction heating unit 10. The induction heating cooker 1 is an induction heating apparatus that forms an eddy current on a heated body (not shown) placed above the top plate 8 by a high-frequency magnetic field generated by the induction heating unit 10.

  FIG. 2 is a bottom view when the induction heating unit 10 according to the first embodiment is viewed from below. The induction heating unit 10 shown in FIG. 2 is disposed between a substantially square inner coil 20 wound in a plane, a circular outer coil 30, and the inner coil 20 and the outer coil 30. And a temperature sensor 40 such as a thermistor. The temperature sensor 40 measures the temperature of the back surface of the top plate 8, and feeds back a temperature signal indicating a heating state to a control circuit (not shown) to ensure safe and efficient driving. The temperature sensor 40 is not limited to an electrical temperature sensor such as a thermistor, and may have any other form such as an optical sensor as long as it measures the temperature of the back surface of the top plate 8. Can be adopted.

  The inner coil 20 according to this embodiment is wound in a substantially square shape, not a circle, unlike the one described in the above-mentioned Patent Document 1. Further, the substantially square inner coil 20 is configured to be close to the circular outer coil 30 partially, that is, in a partial region (hereinafter referred to as “proximity region 50”) surrounded by a broken line 50 in FIG. ing. The temperature sensor 40 is disposed when the inner coil 20 is separated from the outer coil 30, that is, in a region surrounded by a broken line 60 in FIG. 2 (hereinafter referred to as “separated region 60”).

  The induction heating unit 10 also includes a plurality of magnetic members 70 that are arranged so as to partially traverse the inner coil 20 and the outer coil 30 in the radial direction and to magnetically couple them. The magnetic member 70 is made of, for example, ceramics (ferrite material) containing iron oxide as a main component (hereinafter, also simply referred to as “ferrite” in the present specification), has high magnetic permeability, and each of the heating coils 20, 30. The heating efficiency of the pan can be increased by reducing the magnetic resistance of the magnetic path generated by the above and increasing the magnetic field.

  In the induction heating unit 10 configured as described above, the area occupation ratio of the substantially square inner coil 20 can be increased inside the outer coil 30. When the area occupancy of the inner coil 20 inside the outer coil 30 is increased, the pan is induction-heated by the heating coil 20 having a larger area, so that the heat conversion efficiency of the object to be heated by the induction heating unit 10 is improved. The pan can be heated evenly.

  Here, the area occupancy of the circular inner coil 20 according to the conventional technique and the area occupancy of the substantially square inner coil 20 according to this embodiment will be verified below using a simplified specific example.

  In FIG. 3 showing the prior art, the inner diameter of the outer coil 30 is 10 cm, and the outer diameter and inner diameter of the inner coil 20 are 7 cm and 3 cm, respectively. On the other hand, in FIG. 2 showing this embodiment, the inner diameter of the outer coil 30 is similarly 10 cm, and the lengths of one side of the outer square 21 and inner square 22 of the inner coil 20 are 14 cm and 6 cm, respectively.

At this time, the area S ₀ inside the outer coil 30 is 100πcm ² .
S ₀ = 10 ² × π
The area S ₁ of the circular inner coil 20 in FIG. 3 is 40πcm ² .
S ₁ = 7 ² × π-3 ² × π = 40π
Therefore, in the prior art shown in FIG. 3, the area occupation ratio of the inner coil 20 in the inner region of the outer coil 30 is 40% (= S ₁ / S ₀ ).

On the other hand, the area S 2 of the square inner coil 20 in FIG. ₂ is about 160 cm ² .
S ₂ = 14 ² −6 ² = 160
Therefore, in FIG. 2 showing the first embodiment, the area occupation ratio of the circular inner coil 20 in the inner region of the outer coil 30 is about 51% (= S ₂ / S ₀ ).

  As described above, by changing the shape of the inner coil 20 from a circular shape to a substantially square shape, the area occupancy of the inner coil 20 can be significantly increased from 40% to about 51%. In addition to improving the heat conversion efficiency, it is possible to uniformly heat a heated object such as a pan.

Embodiment 2. FIG.
Embodiment 2 of the induction heating cooker according to the present invention will be described in detail below with reference to FIG. The induction heating cooker 1 of the second embodiment has the same configuration as that of the induction heating cooker 1 of the first embodiment except that the inner coil 20 has an elliptical shape. Omitted.

FIG. 4 is a bottom view when the induction heating unit 10 according to the second embodiment is viewed from below.
Similarly, the area occupation rate of the elliptical inner coil 20 in the inner region (S ₀ ) of the outer coil 30 will be examined below.

When the major axis and minor axis of the outer circumference ellipse 23 of the ellipse-shaped inner coil 20 are 10 cm and 7 cm, respectively, and the major axis and minor axis of the inner circumference ellipse 24 of the inner coil 20 are 6 cm and 3 cm, respectively, the inner side of the ellipse of FIG. The area S _{3 of the} coil 20 is 52πcm ² .
S ₃ = 10 × 7 × π−6 × 3 × π = 52π
Therefore, according to the second embodiment, the area occupation ratio of the elliptical inner coil 20 in the inner region of the outer coil 30 in FIG. 4 is 52% (= S ₃ / S ₀ ).

  Therefore, by changing the shape of the inner coil 20 from a circular shape to an elliptical shape, the area occupancy of the inner coil 20 can be increased from 40% to 52%. While improving heat conversion efficiency, to-be-heated bodies, such as a pan, can be heated uniformly.

Embodiment 3 FIG.
Embodiment 3 of the induction heating cooker according to the present invention will be described in detail below with reference to FIG. The induction heating cooker 3 of the third embodiment has the same configuration as the induction heating cooker 1 of the first embodiment, except that the inner coil 20 has the same shape as the field used in the track race. Explanation of overlapping points is omitted.

FIG. 5 is a plan view of the induction heating unit 10 according to Embodiment 3 when viewed from below.
As shown in FIG. 5, the inner coil 20 of the third embodiment is a shape in which a pair of half-doughnut-shaped portions 25 and a rectangular-shaped portion 26 are connected (hereinafter referred to as “pseudo-elliptical shape” or “race track shape”). ).

Similarly, the area occupation ratio of the pseudo-elliptical inner coil 20 in the inner region (S ₀ ) of the outer coil 30 is examined.

When the outer radius and the inner radius of the half donut-shaped portion 25 of the race track of the inner coil 20 are 7 cm and 3 cm, respectively, and the vertical and horizontal lengths of the rectangular portion 26 are 6 cm and 4 cm, respectively, the pseudo-elliptical shape of FIG. The area S ₄ of the inner coil 20 is about 173.6 cm ² .
S ₄ = 7 ² × π-3 ² × π + 2 × 4 × 6 = about 173.6
Therefore, according to the third embodiment, the area occupancy ratio of the pseudo-elliptical inner coil 20 in the inner region of the outer coil 30 in FIG. 5 is about 55.3% (= S ₄ / S ₀ ).

  Therefore, by changing the shape of the inner coil 20 from a circular shape to a pseudo-elliptical shape, the area occupancy of the inner coil 20 can be increased from 40% to 55.3%, and as in the above embodiment, induction heating is performed. While improving the heat conversion efficiency of the part 10, to-be-heated bodies, such as a pan, can be heated uniformly.

Embodiment 4 FIG.
Embodiment 4 of the induction heating cooker according to the present invention will be described in detail below with reference to FIG. The induction heating cooker 1 of the fourth embodiment has the same configuration as that of the induction heating cooker 1 of the first embodiment except that the inner coil 20 has a circular shape and the outer coil 30 has an elliptical shape. Therefore, the description of overlapping points is omitted.

FIG. 6 is a plan view of the induction heating unit 10 according to the fourth embodiment when viewed from below.
Similarly, the area occupation rate of the circular inner coil 20 in the inner region (S ₀ ) of the outer coil 30 will be examined.

When the major axis and minor axis of the inner peripheral ellipse 27 of the outer coil 30 are 10 cm and 7 cm, respectively, and the outer diameter and inner diameter of the inner coil 20 are 7 cm and 3 cm, respectively, the inner area S of the elliptical outer coil 30 of FIG. ₅ is 70πcm ² .
S ₅ = 10 × 7 × π
The area _{S 6} of the inner coil 20 is 40πcm ^2.
S ₆ = 7 ² × π-3 ² × π
Therefore, according to the fourth embodiment, the area occupation ratio of the circular inner coil 20 in the inner region of the outer coil 30 in FIG. 6 is 57.1% (= S ₆ / S ₅ ).

  Therefore, by making the inner coil 20 circular and the outer coil 30 elliptical, the area occupancy of the inner coil 20 is increased from 40% to 57.1% compared to the first embodiment. As in the above-described embodiment, the heat conversion efficiency of the induction heating unit 10 can be improved and a heated object such as a pan can be heated uniformly.

  In the fourth embodiment, the inner coil has a circular shape, while the outer coil has an elliptical shape. However, the outer coil has a rectangular shape or a pseudo-elliptical shape in addition to the elliptical shape. However, the same effect can be realized.

Embodiment 5 FIG.
With reference to FIG. 7, Embodiment 5 of the induction heating cooker according to the present invention will be described in detail below. The induction heating cooker 1 of the fifth embodiment has the same configuration as the induction heating cooker 1 of the first embodiment except that both the inner coil 20 and the outer coil 30 have an elliptical shape, and therefore overlaps. A description of the points is omitted.

FIG. 7 is a plan view when the induction heating unit 10 according to the fifth embodiment is viewed from below.
Similarly, the area occupation ratio of the circular inner coil 20 in the inner region of the outer coil 30 will be examined.

When each 10cm and 8.5cm the major axis and the minor axis of the inner circumferential ellipse 28 of the outer coil 30 in FIG. 7, the inner area _{S 7} of the outer coil 30 of the elliptical shape of Figure 7 is 85πcm ^2.
S ₇ = 10 × 8.5 × π
On the other hand, when the major axis and minor axis of the outer circumference ellipse 29 of the inner coil 20 are 8.5 cm and 7 cm, respectively, and the major axis and minor axis of the inner circumference ellipse of the inner coil 20 are 4 cm and 3 cm, respectively, the area S _{8 of the} inner coil 20 Is 47.5πcm ² .
S ₈ = 8.5 × 7 × π−3 × 4 × π
Therefore, according to the fifth embodiment, the area occupation ratio of the circular inner coil 20 in the inner region of the outer coil 30 in FIG. 7 is about 55.9% (= S ₈ / S ₇ ).

  Therefore, by making the inner coil 20 and the outer coil 30 elliptical, the area occupancy of the inner coil 20 can be increased from 40% to 55.9% compared to the first embodiment. Similar to the embodiment, it is possible to improve the heat conversion efficiency of the induction heating unit 10 and to uniformly heat an object to be heated such as a pan.

Embodiment 6 FIG.
With reference to FIG. 8, Embodiment 6 of the induction heating cooker according to the present invention will be described in detail below. The induction heating cooker 1 of the sixth embodiment has the same configuration as that of the third embodiment except that a larger number of ferrites 70 are arranged in the vicinity of the separated region 60 than the adjacent region 50. Description is omitted.

  Generally, in the first to fifth embodiments described above, the inner coil 20 and the outer coil 30 are disposed substantially in contact with or in close proximity to each other in the proximity region 50, so The magnetic flux density tends to be maximum. That is, the heat generation efficiency of the pan in the proximity region 50 is greater than the heat generation efficiency of the pan in the separation region 60, and the amount of heat generated in the pan may vary. In order to eliminate or at least partially alleviate this variation in the amount of heat generation, more ferrite 70 that lowers the magnetic resistance of the magnetic path generated by the heating coil and concentrates the magnetic flux in the vicinity of the separation region 60 than in the proximity region 50. It is preferable to arrange. Specifically, a large number of ferrites 70 are unevenly distributed in the vicinity of the separation region 60 from the proximity region 50 (the number of ferrites 70 arranged per unit area is increased). Thus, according to the present embodiment, it is possible to suppress the variation in the heat generation efficiency of the heated body due to the heating coil having a non-circular shape.

Instead of making the ferrite 70 unevenly distributed in the vicinity of the separation region 60 from the proximity region 50, the cross-sectional area of each ferrite 70 arranged at equal intervals is configured to be larger from the proximity region 50 to the separation region 60. Thereby, the magnetic flux density which passes the whole pan may be equalized, and the variation in the heat generation efficiency of the object to be heated may be suppressed.
The sixth embodiment can be applied not only to the third embodiment but also to the induction heating unit 10 described in any other embodiment.

Modification 1
A modification that can be applied to any one of the above-described first to sixth embodiments will be described below with reference to FIG.
The induction heating cooker 1 of Modification 1 has an additional heating coil 80 on the outer side of the outer coil 30. That is, the induction heating part 10 of the modification 1 has the large heating coil 80 for efficiently heating to-be-heated bodies, such as a large pot, in the further outer side of the outer coil 30, as shown in FIG. . Therefore, the large heating coil 80 according to this modification improves the heat conversion efficiency of the induction heating unit 10 by combining with any of the above-described embodiments, and in addition to the effect of heating the pan uniformly, the larger heating coil 80 An inherent effect that the pot can be efficiently heated can be realized.

1: induction heating cooker, 7: housing, 8: top plate, 9: operation unit, 10: induction heating unit, 20: inner coil, 21: outer square, 22: inner square, 23: outer ellipse, 24: Inner circumference ellipse, 25: Half donut-shaped portion, 26: Rectangular shape portion, 27: Inner circumference ellipse, 28: Inner circumference ellipse, 29: Outer circumference ellipse, 30: Outer coil, 40: Temperature sensor, 50: Proximity region, 60 : Separation region, 70: magnetic member (ferrite), 80: large heating coil.

Claims (5)

An inner coil wound in a plane and an outer coil disposed around the inner coil;
Comprising at least one temperature sensor disposed between the inner coil and the outer coil;
Either one of the inner coil and the outer coil has a circular shape, the other has a non-circular shape,
The inner and outer coils are at least partially proximate;
The induction heating cooker, wherein the temperature sensor is disposed where the inner coil and the outer coil are separated from each other.   The induction heating cooker according to claim 1, wherein the inner coil has a rectangular shape, an elliptical shape, or a pseudo-elliptical shape, and the outer coil has a circular shape.   The induction heating cooker according to claim 1, wherein the outer coil has a rectangular shape, an elliptical shape, or a pseudo-elliptical shape, and the inner coil has a circular shape. An inner coil wound in a plane and an outer coil disposed around the inner coil;
Comprising at least one temperature sensor disposed between the inner coil and the outer coil;
Both the inner and outer coils have an elliptical shape;
The inner and outer coils are at least partially proximate;
The induction heating cooker, wherein the temperature sensor is disposed where the inner coil and the outer coil are separated from each other. A plurality of magnetic members for magnetically coupling the inner coil and the outer coil;
The magnetic member is configured to concentrate more magnetic flux in the vicinity of the separation region where the inner coil and the outer coil are separated than in the vicinity of the proximity region where the inner coil and the outer coil are adjacent. The induction heating cooker according to any one of claims 1 to 4, characterized in that

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