JP5012250B2 - Electric rice cooker - Google Patents

Description

  The present invention relates to an electric rice cooker, and more particularly to a side magnetic shielding structure in an electric rice cooker.

  In the case of a conventionally well-known electric rice cooker, especially an electromagnetic induction type rice cooker using a small-capacity earthenware pot, the inner peripheral surface is constituted by a bottomed cylindrical protective frame that detachably accommodates the inner pot. A rice cooker body, a cylindrical metal case constituting the outer peripheral surface of the rice cooker body, and an electromagnetic induction coil disposed below the bottom surface of the protective frame in the rice cooker body. The distance between the electromagnetic induction coil and the metal case is narrow.

  In the case of the electric rice cooker configured as described above, the magnetic induction coil leaks and the metal case is heated. In addition, the heat insulating heater is fixed to the outer periphery of the protective frame with aluminum tape or the like. In the case of things, electric discharge occurred at the seam portion of the aluminum tape.

  In addition, in an electromagnetic induction heating type electric rice cooker or the like in which the electromagnetic induction coil for heating the heat sink on the lid side is disposed on the shoulder of the main body, a magnetic shielding plate for shielding magnetism from the electromagnetic induction coil is provided. In order to appropriately utilize as an auxiliary heating source together with the magnetic shielding function, a part of the annular magnetic shielding plate is opened in a C shape, and an electrical secondary side is provided between both ends of the opened magnetic shielding plate. The thing which connected the load member so that electricity supply was possible has already been proposed (refer patent document 1).

Japanese Patent Application Laid-Open No. 2004-319345.

  By the way, in the case of the electric rice cooker currently disclosed by patent document 1, as a magnetic shielding function which shields the magnetism from the electromagnetic induction coil for the heat sink of the lid | cover side arrange | positioned at the main body shoulder part, and as an auxiliary heating source It is supposed to have a function in one member, but by shielding the magnetism from the electromagnetic induction coil arranged below the bottom of the protective frame in the rice cooker body, the outer peripheral surface of the rice cooker body It is not possible to prevent the influence of magnetism (that is, heat generation) on the cylindrical metal case to be formed.

  The present invention has been made in view of the above points, and can prevent heat generation of the metal case by preventing the leakage of magnetism from the electromagnetic induction coil disposed below the bottom surface of the protective frame. It aims to be able to prevent.

In this invention, as a 1st means for solving the said subject, the rice cooker main body by which the inner peripheral surface was comprised with the bottomed cylindrical protection frame which accommodates an inner pot so that attachment or detachment was possible, and this rice cooker main body A cylindrical metal case constituting an outer peripheral surface, and an electromagnetic induction coil disposed below the bottom surface of the protective frame in the rice cooker body, and a bottom magnetic shielding plate on the inner bottom surface of the rice cooker body In the electric rice cooker formed, the shape of the outer peripheral surface of the protective frame is an inclined surface whose outer diameter decreases as it goes downward from above , and a heat retaining heater is provided on the outer periphery of the side portion of the protective frame. A cylindrical side portion is wound around a holding member made of a good thermal conductor, and the lower outer periphery of the protective frame is sandwiched by the lower portion of the holding member at a predetermined position on the outer peripheral surface of the protective frame. Wearing a magnetic shielding plate .

With the above configuration, the side magnetic shielding plate prevents magnetic leakage from the electromagnetic induction coil disposed below the bottom surface of the protective frame, and heat generation of the metal case is possible. This can be prevented as much as possible, and the side magnetic shielding plate can be attached using the outer peripheral surface shape of the protective frame. In addition, the side magnetic shielding plate can be attached using a holding member that holds the heat-retaining heater, and the attachment structure of the side magnetic shielding plate to the protective frame is strengthened, and the side magnetic shielding plate is generated in the side magnetic shielding plate. The generated heat can be transmitted to the protective frame via the holding member, and acts as an auxiliary heating source for the protective frame.

According to the 1st means of this invention, the rice cooker main body by which the inner peripheral surface was comprised with the bottomed cylindrical protective frame which accommodates an inner pot so that attachment or detachment was possible, and the cylinder which comprises the outer peripheral surface of this rice cooker main body An electric induction coil comprising a metal case having a shape and an electromagnetic induction coil disposed below the bottom surface of the protective frame in the rice cooker main body, and a bottom magnetic shielding plate disposed on the inner bottom surface of the rice cooker main body. In the rice cooker, the shape of the outer peripheral surface of the protective frame is an inclined surface whose outer diameter decreases as it goes from the upper side to the lower side, and a heat retaining heater is formed on the side portion outer periphery of the protective frame with a heat-resistant conductor. A cylindrical side magnetic shielding plate is attached to the lower outer periphery of the protective frame in a state where the upper portion is sandwiched by the lower portion of the holding member at a predetermined position on the outer peripheral surface of the protective frame. Installed below the bottom of the protective frame. Since side leakage of magnetism from the electromagnetic induction coil is prevented by the side magnetic shielding plate, heat generation of the metal case can be prevented as much as possible, and the outer peripheral shape of the protective frame can be reduced. There is an effect that the side magnetic shielding plate can be attached by using. In addition, the side magnetic shielding plate can be attached by using a holding member that holds the heat-retaining heater, the structure for attaching the side magnetic shielding plate to the protective frame is strengthened, and heat generated in the side magnetic shielding plate is generated. Can be transmitted to the protective frame via the holding member, and there is an effect that it acts as an auxiliary heating source of the protective frame.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  In this electric rice cooker, as shown in FIG. 1, for example, a pot made of a non-metallic material (for example, an earthen pot, a ceramic pot, a charcoal pot, etc.) is adopted as the inner pot 3 for storing rice and water. It is comprised by the rice cooker main body 1 comprised so that the pan 3 could be set arbitrarily, and the cover body 2 provided in the upper part of this rice cooker main body 1 so that opening and closing was possible.

  The rice cooker main body 1 constitutes the inner peripheral surface of the rice cooker main body 1 and has a bottomed cylindrical synthetic resin protective frame 4 formed so that the inner pot 3 can be set arbitrarily. A cylindrical metal case 5 constituting the outer surface of the rice cooker body 1, an annular synthetic resin shoulder member 6 for connecting the upper end of the metal case 5 and the upper end of the protective frame 4, and the metal The bottom member 7 is made of a dish-shaped synthetic resin that closes the lower end opening of the case 5. Here, the metal case 5 is comprised, for example with steel plates, such as stainless steel.

  The inner pot 3 includes a bottom portion 8 and a cylindrical portion 9 that stands upright from the bottom portion 8. In this way, the outermost diameter dimension of the induction heating element G provided on the lower surface of the bottom 8 and the inner diameter dimension of the inner pot 3 can be made substantially the same, and the heat generated by the induction heating element G can be reduced. Go to every corner of rice in pot 3.

  An annular support leg 10 is integrally projected on the outer peripheral part of the inner pot bottom 8, and the support leg 10 is disposed on the outer periphery of the bottom of the protective frame 4 at equal intervals in the circumferential direction. The inner pot 3 is housed and supported in the protective frame 4 by coming into contact with three support bases 11, 11, 11 made of an elastic member (for example, silicon rubber).

  On the other hand, the protective frame 4 includes a bottom portion 4a, a cylindrical portion 4b that stands upright from the outer periphery of the bottom portion 4a, and a flange portion 4c that is integrally formed at the upper end of the cylindrical portion 4b. The shape of the outer peripheral surface of the part 4b is an inclined surface whose outer diameter decreases as it goes downward from above. And the heat insulation heater 12 is wound around the outer peripheral side of the said protective frame cylindrical part 4b via the holding member (for example, aluminum tape 13) which consists of a heat good conductor.

  On the lower surface of the bottom portion 8 of the inner pot 3 (that is, on the inner peripheral side of the support leg 10), a metal induction heating element G such as a silver paste capable of self-heating by an eddy current induced therein is used. Is pasted. By the way, a metal spraying heat generating layer acting as an induction heating element may be formed on the inner surface or inner and outer surfaces of the inner pot 3. In some cases, a metal spray heat transfer layer continuous with the metal spray heat generation layer may be formed. In addition, aluminum or an aluminum alloy can also be used as the metal spray heat generating layer and the metal spray heat transfer layer. Furthermore, as the induction heating element G, a metal plate other than a silver paste or a metal sprayed layer can be adopted, and the induction heating element G may be embedded in the inner pot 3.

  A coil cover 14 is provided below the bottom wall portion (bottom portion) 4a of the protective frame 4, a ferrite core is disposed at the lower portion thereof, and the lower surface side of the bottom portion 8 of the inner pot 3 is disposed at the upper portion thereof. Corresponding to the position of the induction heating element G, an electromagnetic induction coil (hereinafter referred to as a work coil) C in which litz wires are concentrically wound is provided, whereby the induction heating element of the inner pot 3 is energized. An eddy current is induced in G to indirectly heat the inner pot 3.

  A sensor part fitting port of a center sensor CS acting as a temperature detecting means is formed at the center of the dish-shaped bottom part 4a of the protective frame 4, and a donut-like shape is formed on the outer peripheral side upper surface of the sensor part fitting hole. A heat shield plate 16 is provided. Further, an aluminum bottom magnetic shielding plate 15 is disposed on the inner bottom surface of the bottom member 7 to prevent the work coil C from affecting the magnetism downward.

  By making the thickness of the lower portion of the side surface corresponding to the outside of the support leg 10 in the inner pot 3 (that is, the support leg 10) thinner than the thickness of the upper portion of the side surface, relatively large air is present between the portion and the protective frame 4. The layer K will be formed and the heat insulation effect can be ensured.

  On the other hand, the lid body 2 is composed of a synthetic resin outer cover 20 that forms an outer peripheral surface of the lid body 2 and that includes a pressure adjusting pipe 19 at the center, and a synthetic resin that is fitted and integrated inside the outer cover 20. A resin inner frame 21, a packing 22a and a metal heat dissipating plate 23 disposed in the inner opening of the inner frame 21, a lid heater 24 provided on the upper surface of the heat dissipating plate 23, and the heat dissipating plate 23 And an inner lid 25 made of metal, which can be opened and closed via a hinge unit 26 with respect to one side of the upper portion of the rice cooker body 1 (ie, the shoulder member 6). It is pivotally supported. The lid 2 is held in a closed state via a lock mechanism 27 on the opposite side of the hinge unit 26. Reference numeral 28 denotes a lock release lever for releasing the lock state of the lock mechanism 26.

  Further, packings 22a and 22b are respectively provided below the outer peripheral edge of the heat radiating plate 23 and below the outer peripheral edge of the inner lid 25, and the inner lid 25 is connected to the flange of the inner pot 3 via the packing 22b. It is made to contact the upper surface part of the part 3a. The inner pot flange portion 3 a has substantially the same thickness as the cylindrical portion 9, and a flat portion on which the packing 22 b is pressed when the lid body 2 is closed is formed on the upper surface thereof. Reference numeral 29 denotes a pressure regulating valve in the pressure regulating pipe 19, 30 denotes a lower side cap thereof, and 31 denotes a pressure regulating ball.

  By the way, in the case of the electric rice cooker of the said structure, since the flange part 3a of the inner pot 3 is easy to cool, the cyclic | annular shoulder heater 32 is arrange | positioned between the flange part 4c of the protective frame 4, and the shoulder member 6, and this shoulder The inner pot flange portion 3 a is heated by the heater 32. In this case, in order to effectively receive the upward heat from the shoulder heater 32, it is desirable to extend the inner pot flange portion 3 a to a position covering the upper side of the shoulder heater 32.

  In the case of the present embodiment, an operation panel unit 33 having various keys and a liquid crystal display device is provided on the side surface on the side opposite to the hinge unit in the rice cooker body 1. The operation board 34 is disposed. On the other hand, a control board cover made of synthetic resin for attaching a control board 36 provided with various electronic components (for example, IGBT, diode bridge, etc.) on the hinge unit 26 side in the space 35 in the rice cooker body 1. 37 is disposed. A cooling fan 39 is attached to the lower end of the control board 36 via a heat sink 40.

  Although the rice cooker body 1 can be made compact with the above configuration, the control board 36 provided with various electronic components (for example, IGBT, diode bridge, etc.) and the outer surface of the rice cooker body 1 are configured. There is a risk of electric leakage from the control board 36 side to the metal case 5 side because the distance to the metal case 5 to be too close becomes. Therefore, in the present embodiment, an insulating cover 38 made of an electrically insulating material is disposed on the inner surface side of the metal case 5.

  In the present embodiment, the insulating cover 38 and the control board cover 37 form a cooling space S as a path for cooling air from the cooling fan 39. That is, the cooling space S opened downward by the control board cover 37 positioned on the inner pot 3 side and the insulating cover 38 positioned on the metal case 5 side in the space on the hinge unit 26 side in the rice cooker body 1. Thus, the substrate holder 42 having the structure is configured. A hanging wall 38a that covers up to half the vertical height of the cooling fan 39 is integrally extended at the lower end of the insulating cover 38 in order to stabilize the air volume of the cooling fan 39 by the orifice effect.

  By the way, in the case of the electric rice cooker of the said structure, the magnetic flux of the work coil C leaks and the malfunction that the metal case 5 will be heated arises, and there exists a possibility that discharge may occur in the joint part of the aluminum tape 13. FIG. Accordingly, in the present embodiment, a cylindrical aluminum side magnetic shielding plate 17 that is engaged and press-fitted at a predetermined position on the outer peripheral surface of the protective frame 4 is provided on the lower outer periphery of the protective frame 4. It is installed. The inner diameter of the side magnetic shielding plate 17 is substantially the same diameter (or slightly smaller) as the outer diameter at a predetermined position on the outer peripheral surface of the protective frame 4, and is engaged and press-fitted from below the protective frame 4. (See FIG. 3). Further, the lower end portion of the side magnetic shielding plate 17 is positioned above the upper surface of the work coil C. With the above configuration, the side magnetic shielding plate 17 prevents magnetic leakage from the work coil C disposed below the bottom surface of the protective frame 4. Heat generation can be prevented as much as possible, and the side magnetic shielding plate 17 can be attached using the outer peripheral shape of the protective frame 4. Moreover, the magnetism from the work coil C to the side can be effectively shielded.

  That is, the magnetic flux J from the work coil C is blocked by the side magnetic shielding plate 17 and cannot reach the metal case 5.

  Here, the closer the distance between the lower end of the side magnetic shielding plate 17 and the upper surface of the work coil C, the higher the magnetic shielding effect, but the cooling air from the cooling fan 39 is less likely to be sucked for cooling the work coil C. Therefore, the distance H is necessary to some extent. Further, the higher the height L of the side magnetic shielding plate 17, the higher the magnetic shielding effect, but it can be limited to a height necessary and sufficient to shield the magnetic flux from the work coil C. For example, as shown in FIG. 3, in the case of the magnetic fluxes J1 and J2, heat is generated in the induction heating element G provided at the bottom of the inner pot 3, and in the case of the magnetic flux J3, the magnetic shielding is performed on the bottom magnetic shielding plate 15, and the magnetic flux J4. , J5, the side magnetic shielding plate 17 is magnetically shielded.

  Moreover, in the present embodiment, the upper portion of the side magnetic shielding plate 17 is sandwiched between lower portions of the aluminum tape 13 that is a holding member that holds the heat retaining heater 12. In this way, the side magnetic shielding plate 17 can be attached using the aluminum tape 13 that holds the heat retaining heater 12, and the attachment structure of the side magnetic shielding plate 17 to the protective frame 4 is strengthened. The heat generated in the side magnetic shielding plate 17 can be transmitted to the protective frame 4 via the aluminum tape 13 and acts as an auxiliary heating source for the protective frame 4.

  Further, a heat insulating material 18 is disposed on the outer peripheral side of the aluminum tape 13 and the side magnetic shielding plate 17. If it does in this way, the heat dissipation to the outward of the heat | fever which generate | occur | produced in the side magnetic shielding board 17 can be suppressed with the heat insulating material 18, and the efficiency as an auxiliary | assistant heating source of the protective frame 4 can be improved.

  The bottom magnetic shielding plate 15 and the side magnetic shielding plate 17 are made of aluminum in the present embodiment, but may be made of other materials as long as they can be magnetically shielded.

  The invention of the present application is not limited to the above-described embodiment, and it is needless to say that the design can be appropriately changed without departing from the gist of the invention.

It is a longitudinal cross-sectional view of the electric rice cooker concerning embodiment of this invention. It is II-II sectional drawing of FIG. It is an expanded sectional view showing an important section of an electric rice cooker concerning an embodiment of the invention of this application.

1 is a rice cooker body 2 is a lid 3 is an inner pot 4 is a protective frame 5 is a metal case 12 is a heat retaining heater 13 is a holding member (aluminum tape)
15 is a bottom magnetic shielding plate 17 is a side magnetic shielding plate 18 is a heat insulating material C is an electromagnetic induction coil (work coil)

Claims (1)

A rice cooker body whose inner peripheral surface is configured by a bottomed cylindrical protective frame that detachably accommodates an inner pot, a cylindrical metal case that constitutes the outer peripheral surface of the rice cooker body, and the inside of the rice cooker body And an electromagnetic induction coil disposed below the bottom surface of the protective frame, and an electric rice cooker having a bottom magnetic shielding plate disposed on the inner bottom surface of the rice cooker body, A shape of the outer peripheral surface is an inclined surface whose outer diameter decreases as it goes downward from above , and a heat retaining heater is wound around the side portion outer periphery of the protective frame via a holding member made of a heat good conductor, An electric rice cooker having a cylindrical side magnetic shielding plate attached to a lower outer periphery of the protective frame in a state where the upper portion is sandwiched by a lower portion of the holding member at a predetermined position on the outer peripheral surface of the protective frame . .

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