JP2006120338A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker capable of absorbing a leakage magnetic field without increasing the height of a main body. <P>SOLUTION: The induction heating cooker comprises: an upper case 2 and a lower case 3 separated into upper and lower parts and forming an enclosure; a top plate 1 provided on the upper case 2 for placing an object to be heated thereon; a heating coil 5 provided below the top plate 1; a coil base 6 for holding the heating coil 5; a shield ring 15 provided in the shape of a ring on the periphery of the heating coil 5; a substrate (not shown) of an inverter section for supplying power to the heating coil 5; a fan motor 10 for cooling components on the substrate and the heating coil 5; an air inlet port 13 provided for the lower case 3; and an air outlet port (not shown) provided for the lower case 3 and/or the upper case 2. Part of the shield ring 15 covers a portion above a winding 16 provided inside the fan motor 10. This allows leakage magnetic fields generated from both of the heating coil 5 and the winding 16 to be absorbed by one component, and it is therefore possible to reduce the leakage magnetic fields without increasing the height of the main body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an induction heating cooker for cooking a magnetic pot placed on a top plate by electromagnetic induction of a heating coil.

  Conventionally, in this type of induction heating cooker, a high-frequency magnetic field (hereinafter referred to as a magnetic field) is generated by flowing a high-frequency current from an inverter circuit to a heating coil, and the magnetic field placed on the top plate by the magnetic field An eddy current is generated and the bottom of the pan generates heat due to its electrical resistance (see, for example, Patent Document 1).

  Most of the magnetic field generated from the heating coil is absorbed by the pan and converted to heat, but there is also a magnetic field that leaks from the periphery of the pan (leakage magnetic field). This leakage magnetic field may affect nearby electrical appliances.

  Recently, there are reports of concern about the impact on the human body, and each company is working to reduce the leakage magnetic field.

  FIG. 7 is a cross-sectional view showing the configuration of the induction heating cooker described in Patent Document 1.

Reference numeral 20 denotes a top plate on which a heated object 21 such as a pan is placed, and a heating coil 23 supported by a heating coil support 22 is provided below the top plate. As one of the efforts for reducing the leakage magnetic field, in order to reduce the leakage magnetic field from the heating coil 23, a shield ring 24 having a single cross-sectional shape is provided on the outer periphery of the heating coil 23, so Magnetic flux is absorbed. A control board 25 for controlling the heating coil 23 and the like, a cooling fan motor (not shown), and the like are disposed below the heating coil 23.
Japanese Patent Laid-Open No. 10-302953 (FIG. 1)

  As a generation source of the leakage magnetic flux, there is a motor winding of a cooling fan motor in addition to the heating coil 23, but in the configuration of the conventional induction heating cooker, the fan motor overlaps below the heating coil 23. Therefore, if a shield part dedicated to the fan motor is added separately, the attachment position of the heating coil is moved upward, and as a result, the whole induction heating cooker becomes higher and larger, especially for desktop use. One small induction heating cooker has a problem that it is very unusable.

  This invention solves the said conventional subject, and it aims at providing the induction heating cooking appliance which reduced the leakage magnetic field reliably while reducing the height of a cooking appliance main body.

  In order to solve the above-described conventional problems, an induction heating cooker according to the present invention includes a top plate and a bottom case that are divided into upper and lower portions and an outer shell, and a top plate on the case on which an object to be heated is placed. A heating coil disposed below the top plate, a coil base for holding the heating coil, a shield ring disposed in a ring shape on the outer periphery of the heating coil, and a substrate for supplying current to the heating coil A fan motor for cooling the components on the board and the heating coil, an air inlet provided under the case, and an air outlet provided under the case and / or on the case, The upper part of the winding is covered with a part of the shield ring, not only to absorb the leakage magnetic field generated from the heating coil, but also from the winding of the rotating fan motor. A leakage magnetic field can be absorbed by the same component at the same time, and a wide range of magnetic flux can be absorbed by the entire cooker, the leakage magnetic field can be reduced, and an induction heating cooker that suppresses the height of the entire cooker is provided. it can.

  The induction heating cooker of the present invention can simultaneously absorb the leakage magnetic field generated from the fan motor without reducing the ability to absorb the leakage magnetic field generated from the heating coil, and suppress the height of the entire cooking device. A cooker can be provided.

  A first invention includes an upper and lower cases that are divided into upper and lower parts, an upper case, a top plate that is provided on the case and on which an object to be heated is placed, and a heating coil disposed below the top plate, A coil base for holding the heating coil, a shield ring arranged in a ring shape on the outer periphery of the heating coil, a substrate for supplying current to the heating coil, and components on the substrate and the heating coil are cooled. A fan motor, an intake port provided under the case, and an exhaust port provided under the case and / or on the case are covered with a part of the shield ring above the winding in the fan motor. In this way, not only can the leakage magnetic field generated from the heating coil be absorbed, but also the leakage magnetic field generated from the winding of the rotating fan motor can be simultaneously absorbed by the same component. Absorb a wide range of magnetic flux from the entire cooker, along with reducing the leakage magnetic field, it is possible to provide an induction heating cooker with reduced cooker overall height.

  In the second invention, in particular, the portion of the shield ring of the first invention that covers the upper part of the winding in the fan motor has a flat cross section compared to the other portions. The installation height of the heating coil can be lowered without greatly reducing the area and surface area, and the overall height of the cooking device can be kept low without deteriorating the leakage magnetic field and the cooling performance of the heating coil.

  In the third invention, in particular, the coil base is not interposed between the shield ring of the first or second invention and the winding in the fan motor, and the shield ring is an aluminum having good heat conduction. Because copper and copper are used, the heat of the coil base on which the heating coil is mounted can be conducted and cooled just above the fan motor, suppressing the temperature rise of components on the board installed under the coil base As a result, the temperature rise in the entire body can be suppressed.

  In the fourth invention, in particular, the shield ring of any one of the first to third inventions is provided with at least one through hole in a portion covering the upper part of the winding in the fan motor. Thus, the influence of the airflow on the surface of the heating coil can be reduced by the obstacle, and the heating coil can be cooled both from the surface side by the cooling air and from the back side by heat conduction.

  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)
1 is an external perspective view of the induction heating cooker according to the first embodiment of the present invention, FIG. 2 is a plan view showing the internal configuration of the induction heating cooker, and FIG. 3 is the induction heating cooker. The perspective view of a shield ring, a heating coil, and a coil base, FIG. 4 is a fragmentary sectional view of the induction heating cooking appliance.

  In FIG. 1, the outline of the main body 18 of the induction heating cooker is formed such that the upper case 2 and the lower case 3 are combined vertically, and the upper case 2 is made of heat-resistant tempered glass, ceramics, etc. The top plate 1 on which the object to be heated is placed is bonded. Although the top plate 1 in the figure is a rectangular plane, there is no particular problem even if it is round or grooved. In addition, an operation unit 4 having a liquid crystal display window is provided on a surface lower than the top plate 1 at the front part of the case 2.

  FIG. 2 shows a state in which the upper case 2 is removed as viewed from above. A heating coil 5 is provided almost at the center of the lower case 3, and a substrate 7 of the inverter unit is placed under the heating coil 5. The operation unit substrate 9 is placed on the right side, and the power source substrate 8 is placed on the right rear side. In addition, a fan motor 10 is provided on the left front side of the heating coil 5 to cool a heat sink (not shown) to which a heat-generating component attached to the inverter board 7 is fixed, other components on the board, and the heating coil 5. It is designed to send cooling air to it.

  Therefore, there is a circular squirrel-cage intake port 13 (see FIG. 4) below the fan motor 10 under the case 3, and the exhaust port 12 is provided on the side surface and bottom surface of the case lower 3 away from the intake port 13. Yes. The rotation direction of the fan motor 10 is clockwise when viewed from above the main body 18, and a rib (not shown) that constitutes a casing (not shown) connected by R so that the radius gradually increases in the blowing direction. (Not shown) are provided on the lower case 3 and a part of the upper case 2.

  The direction of the wind is rectified by this rib, and the place where the wind speed is fast is directed to the heat sink with the largest amount of heat generation on the substrate 7 of the inverter section. The wind is also blown upward, and the wind in this direction cools the coil base 6 and the heating coil 5 and flows toward the exhaust port 12.

  The heating coil 5 is formed by winding a strand of bundled strands in a disk shape, and is placed on a coil base 6 made of an insulator in which ferrite (not shown) is radially arranged. It is pinched and fixed. On the outer periphery of the heating coil 5, a shield ring 15 made of a conductor that is not heated by induction heating such as aluminum or copper is provided at a certain distance so as to be below the surface of the heating coil 5. Yes.

  A sensor 14 for detecting temperature is provided between the heating coil 5 and the top plate 1. Each sensor 14 is held by the coil base 6 via a spring (not shown), and is configured to constantly contact the back side of the top plate 1. If a plurality of sensors 14 can be installed, the temperature of the top plate 1 can be set in a wider range by providing one at the approximate center of the heating coil 5 and the other between the heating coils 5 and outside the heating coil 5. Can detect the difference between the heat generation temperature due to the magnetic flux density in the radial direction of the heating coil 5, and the difference between the pan bottom temperature and the top plate temperature due to various sizes of pans, pan placement, pan bottom warp, etc. can do.

  The heating coil 5 is placed on the coil base 6 and sandwiched between the coil holders 11. The reactance of the coil varies greatly depending on the distance between the heating coil 5 and the ferrite in the coil base 6, and the variation in the thermal efficiency during heating increases. Therefore, a configuration in which the distance is stabilized is advantageous.

  As shown in FIG. 3, the shape of the shield ring 15 is a ring shape having substantially the same cross-sectional shape, but the portion located above the winding 16 in the fan motor 10 (the left front direction in the figure) is , Flatter than other parts. Although this portion is flat, it is desirable that the cross-sectional area and the surface area are not extremely smaller than the other portions, and are substantially equal or more.

  In FIG. 4, a plurality of magnets 10 b are attached to the inner periphery of the components constituting the impeller (blade) 10 a inside the fan motor 10, and the current flowing through the winding 16 is controlled at a position facing it. And the electromagnet 10c which can change a pole one after another is attached, and the impeller 10a can rotate at high speed continuously. The shield ring 15 is formed and fixed so that the flat portion 15a of the shield ring 15 covers the upper portion of the winding 16 in the fan motor 10 by a certain distance.

  The operation and action of the induction heating cooker configured as described above will be described below.

  A high frequency current flows from the substrate 7 of the inverter part to the heating coil 5 to generate a magnetic field. Due to this magnetic field, an eddy current is generated at the bottom of a magnetic pot (not shown) placed on the top plate 1, and the pot itself generates heat due to electric resistance to the current. A magnetic field is uniformly generated from the inside to the outside around the heating coil 5 through which a high-frequency current flows. However, ferrite is radially arranged on the coil base 6 holding the heating coil 5 to repel magnetic flux. By doing so, the magnetic flux density above the heating coil 5 (top plate 1 side) is increased, and the magnetic field received by the pan is increased.

  When the diameter of the pan is larger than the diameter of the heating coil 5, most of the magnetic flux is absorbed by the pan, and the leakage magnetic field decreases. However, as the pan becomes smaller, the magnetic field generated from the outer periphery of the heating coil 5 is absorbed by the pan. Without leaking out of the pan. When a shield ring 15 made of a conductor such as aluminum is provided on the outer periphery of the heating coil 5 against such a magnetic field leaking from the lateral direction of the heating coil 5, the magnetic flux that goes out of the pan is absorbed. Can do.

  The magnetic field is generated not only from the heating coil 5 but also from the winding 16 in the fan motor 10 necessary for cooling the inverter. In order to absorb the magnetic flux generated from the winding 16, a shield ring 15 provided on the outer periphery of the heating coil 5 is extended to above the winding 16 of the fan motor 10, whereby the magnetic flux generated from the winding 16 is increased. Absorb.

  In order to efficiently absorb the magnetic flux, it is effective to increase the thickness of the shield ring 15 and increase the cross-sectional area and the surface area. For this reason, a shield ring having a cross section close to a square is effective, but the shape of only the upper portion of the fan motor 10 is flat, and by securing a cross-sectional area, without reducing the performance of magnetic flux absorption, The mounting height of the heating coil 5 can be reduced. Thereby, the height of the whole main body 18 can be made low.

  Further, in the main body 18 having the same height, by providing the thin flat portion 15a above the fan motor 10, the thickness of the impeller 10a of the fan motor 10 can be increased accordingly, so that the pressure and the air volume can be increased. In addition, even in a tabletop induction heating cooker in which the space inside the main body 18 is narrow, the cooling air can be forcibly sent, and a compact induction heating cooking appliance with a reduced height can be provided.

(Embodiment 2)
FIG. 5 is a partial sectional view of an induction heating cooker according to the second embodiment of the present invention, and FIG. 6 is a perspective view of a shield ring, a heating coil, and a coil base of the induction heating cooker.

  In this embodiment, as shown in FIGS. 5 and 6, the flat portion 15 a is rounded out without interposing the coil base 6 between the winding 16 inside the fan motor 10 and the flat portion 15 a of the shield ring 15. In addition, the flat portion 15a is provided with a through hole 15b, and the configuration of the other portions is the same as that of the first embodiment.

  A propeller-type impeller 10a is attached to the fan motor 10, and the direction in which the wind blows is upward from the bottom. For this reason, in the first embodiment, the cooling air necessary for cooling the surface of the heating coil 5 hits the coil base 6 and is bent in the lateral direction, and is constituted by ribs on the case upper 2 and the case lower 3. In this embodiment, there is no coil base above the winding 16 and the flat portion 15a of the shield ring 15 is flowed along the casing. Since there is the through hole 15b, the cooling air flows smoothly to the surface of the heating coil 5 as indicated by the arrow, and the heating coil 5 can be efficiently cooled.

  Further, since the obstacle directly above the fan motor 10 is reduced, the ventilation resistance is reduced, leading to a reduction in the load on the fan motor 10 and a reduction in noise.

  In addition, aluminum or copper used for the material of the shield ring 15 has excellent thermal conductivity, and can easily transfer heat from the coil base 6 holding the shield ring 15 and thus the heating coil 5. The heat of the heating coil 5 can be conducted to the portion where the surface area of the flat portion 15a of the shield ring 15 where the wind hits is widened just above the side, and this portion can be efficiently cooled. Therefore, the temperature of the heating coil 5 and the coil base 6 on the leeward side (right rear side in the figure) where the wind cannot easily reach can be lowered, and the heat to the components on the substrate 7 of the inverter section directly under the coil base 6 can be reduced. The amount of transmission can be suppressed, and the exhaust temperature from the main body 18 can be reduced.

  As described above, the induction heating cooker according to the present invention can reduce the leakage magnetic field from two magnetic flux generation sources by one shield ring, and can reduce the height of the main body, so that it can be used in a desktop or built-in type. It can be applied to all types of thin induction heating cookers.

External view of induction heating cooker in Embodiment 1 of the present invention The top view which shows the internal structure of the induction heating cooking appliance Perspective view of shield ring, heating coil and coil base of same induction heating cooker Partial sectional view of the induction heating cooker The fragmentary sectional view of the induction heating cooking appliance in Embodiment 2 of this invention Perspective view of shield ring, heating coil and coil base of same induction heating cooker Cross-sectional view of a conventional induction heating cooker

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Top plate 2 Case top 3 Case bottom 4 Operation part 5 Heating coil 6 Coil base 7, 8 Board | substrate 10 Fan motor 12 Exhaust port 13 Inlet port 15 Shield ring 16 Winding

Claims (4)

Upper and lower case parts that are divided into upper and lower parts, a top plate provided on the case on which an object to be heated is placed, a heating coil disposed below the top plate, and holding the heating coil A coil base, a shield ring arranged in a ring shape on the outer periphery of the heating coil, a substrate that supplies current to the heating coil, a fan motor that cools the components on the substrate and the heating coil, and the case Induction heating cooking comprising an intake port provided below and an exhaust port provided below and / or above the case and covering the upper part of the winding in the fan motor with a part of the shield ring vessel. The induction heating cooker according to claim 1, wherein a portion of the shield ring that covers the upper part of the winding in the fan motor has a flat cross section as compared with other portions. The induction heating cooker according to claim 1 or 2, wherein a coil base is not interposed between the shield ring and the winding in the fan motor. The induction heating cooker of any one of Claims 1-3 which provided the at least 1 through-hole in the part which covers the upper direction of the coil | winding in a fan motor of a shield ring.

Images