JP2595368Y2 - Electric cooker - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric cooker such as a hot plate, an electric pot, an electric rice cooker, etc., for inductively heating a member to be heated by an induction heating coil.

[0002]

2. Description of the Related Art Conventionally, in an electric cooker provided with an induction heating coil, metal lines other than a member to be heated (an inner pot in an electric rice cooker) are abnormally heated by magnetic field lines generated, or the magnetic field lines leak to the surroundings. As shown in the bottom view of FIG. 4, in order to prevent the
A ferrite 9 having a high magnetic permeability is arranged from the lower side to the side of the coil 5. Usually, a plurality of such ferrites 9 are evenly arranged radially from the winding center of the coil 5. As a result, most of the generated magnetic force lines below and beside the coil 5 pass through the ferrite 9 and do not adversely affect the surroundings.

[0003]

However, the lines of magnetic force generated by the coil 5 are not confined to the printed circuit board 7, which is a component, or the coil 5 to prevent leakage of the lines of magnetic force.
Under the influence of the shape of a shielding plate (not shown) provided around the periphery as shown by a two-dot chain line. When the coil 5 is wound at two locations on the inner peripheral side and the outer peripheral side,
The winding state of the coil 5 is different at the position where the two winding portions are connected, which causes deformation of the lines of magnetic force.
Such deformation of the lines of magnetic force has caused a problem that it hinders uniform heating of the member to be heated. In particular, when the number of ferrites was reduced from the viewpoint of cost and weight, this problem became remarkable. SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an electric cooker having an induction heating coil capable of minimizing leakage of lines of magnetic force.

[0004]

According to the first aspect of the present invention, a plurality of ferrites are provided from below to a side of an induction heating coil for induction heating a member to be heated. Accordingly, in the electric cooker configured to prevent the magnetic field lines from leaking downward and to the side, the distribution center of the magnetic field lines generated from the induction heating coil in the heated member substantially coincides with the center of the heated member. In this case, the ferrites are arranged unequally.

In the invention according to claim 2, the magnetic permeability of each of the ferrites is set such that the distribution center of the lines of magnetic force generated by the induction heating coil in the member to be heated substantially coincides with the center of the member to be heated. Alternatively, the sectional area is changed.

According to a third aspect of the present invention, there is provided an electric cooker having an induction heating coil for induction heating a member to be heated, wherein a shielding plate formed of a resin mixed with ferrite powder is laterally arranged from below the induction heating coil. The distribution density of the ferrite in the shielding plate is changed so that the distribution center of the lines of magnetic force generated by the induction heating coil in the heated member substantially coincides with the center of the heated member. is there.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of an electric rice cooker, and FIG. 2 is a bottom sectional view thereof. In this electric rice cooker, the rice cooker body 1
An inner pan 3 is accommodated in an outer container 2 provided therein, and these are closed by a lid 4. An induction heating coil 5 is provided on the bottom surface of the outer container 2. One of the induction heating coils 5 is wound a plurality of times on each of the inner circumference side and the outer circumference side, and when energized, a magnetic field is generated so that the inner pan 3 can be induction-heated.

[0008] Rice cooking control in the electric rice cooker, such as energization of the induction heating coil 5, is performed by an electronic control unit 6 provided inside the front of the rice cooker main body 1. The electronic control unit 6 includes an L (not shown)
This is a configuration in which an ED, a transistor, and the like are mounted.

On the lower surface of the outer container 2, a mounting plate 8 for holding the induction heating coil 5 is provided. Grooves 8a are formed radially from the center of the bottom surface of the mounting plate 8, and rod-like ferrites 9 are provided in the respective grooves 8a. The arrangement positions of these ferrites 9 are determined so as to be non-uniform in consideration of the influence of the printed circuit board 7, the induction heating coil 5, and the like.

That is, in the present embodiment, the center of distribution of the lines of magnetic force is displaced to the right in FIG. 2 under the influence of the printed circuit board 7 and the like, so that the displacement is corrected by disposing the ferrite 9a. Accordingly, if a magnetic field is generated by energizing the induction heating coil 5, the distribution center of the magnetic field lines and the inner pan 3
Are almost coincident with each other, and the lines of magnetic force generated off the inner pot 3 are reduced. As a result, the inner pot 3 can be efficiently heated, and the amount of electricity to the induction heating coil 5 can be reduced as compared with the related art.

In the above-described embodiment, the ferrite 9 having the same shape is used, and the position of the ferrite 9 is changed so as to make the ferrite 9 less affected by the printed circuit board 7 and the like. You may use a different thing and arrange | position a thing with a different cross-sectional area. Specifically, the ferrite 9c may have a higher magnetic permeability or a larger cross-sectional area than the ferrite 9b in FIG. In this case, the ferrite 9a is unnecessary.

In place of the ferrite 9, a shielding plate 10 for covering the lower and side of the induction heating coil 5 with a resin mixed with ferrite powder may be provided. In this case, as in the above-described embodiment, as a method of making the distribution center of the magnetic field lines generated from the induction heating coil 5 substantially coincide with the center of the inner pot 3, a notch hole 11 is formed in the bottom surface (see FIG. 3),
The distribution density of the ferrite may be changed by reducing the thickness of the portion.

[0013]

As is clear from the above description, according to the electric cooker according to the present invention, the arrangement of the ferrite, its magnetic permeability, the cross-sectional area, or the notch formed in the shielding plate mixed with the ferrite powder. As a result, the center of distribution of the lines of magnetic force generated from the induction heating coil and the center of the member to be heated are made substantially coincident with each other, so that the number of lines of magnetic force deviating from the member to be heated is reduced, and heating can be performed efficiently, and It is also possible to suppress power.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an electric cooker according to the present embodiment.

FIG. 2 is a bottom sectional view of FIG.

FIG. 3 is a bottom sectional view of an electric cooker according to another embodiment.

FIG. 4 is a bottom sectional view of an electric cooker according to a conventional example.

[Explanation of symbols]

3 ... inner pot (member to be heated), 5 ... induction heating coil, 9 ... ferrite.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-7082 (JP, A) JP-A-57-115795 (JP, A) JP-A-6-38868 (JP, A) JP-A-7-78 23849 (JP, A) Hira 2-106133 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A47J 27/00 A47J 37/06

Claims (3)

(57) [Scope of request for utility model registration] An electric cooker in which a plurality of ferrites are arranged from below to a side of an induction heating coil for induction heating a member to be heated, thereby preventing leakage of lines of magnetic force downward and sideways. In the distribution center of the line of magnetic force generated from the induction heating coil in the member to be heated,
An electric cooker, wherein the ferrite is unevenly arranged so as to substantially coincide with the center of the member to be heated. 2. An electric cooker in which a plurality of ferrites are arranged from below to a side of an induction heating coil for induction heating a member to be heated, thereby preventing leakage of magnetic lines of force downward and sideways. In the distribution center of the line of magnetic force generated from the induction heating coil in the member to be heated,
An electric cooker, wherein the magnetic permeability or cross-sectional area of each of the ferrites is changed so as to substantially coincide with the center of the member to be heated. 3. An electric cooker provided with an induction heating coil for induction heating a member to be heated, wherein a shielding plate made of resin mixed with ferrite powder is disposed from below the induction heating coil to a side thereof, and the induction heating coil is provided. An electric cooker wherein the distribution density of ferrite on the shielding plate is changed such that the distribution center of the magnetic field lines generated from the heating coil in the heated member substantially coincides with the center of the heated member. .