JP3131382B2 - Induction heating rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an induction heating rice cooker,
In particular, the present invention relates to an induction heating rice cooker provided with ferrite for enhancing inductive coupling and preventing leakage of magnetic flux.

[0002]

2. Description of the Related Art Conventionally, in an induction heating type rice cooker, an inductive coupling of a magnetic flux generated from a coil disposed on a lower surface of a protective frame by energization is increased to prevent leakage of the magnetic flux. Ferrite is disposed radially (in the radial direction of the coil) (for example, see Japanese Patent Publication No. 7-102172).

[0003]

However, the induction heating type rice cooker requires a large number of ferrites for the above-mentioned purpose and for fixing the coil to the protective frame, resulting in an increase in cost.

[0004] Therefore, an object of the present invention is to provide an induction-heated rice cooker that can suppress the number of ferrites while preventing magnetic flux leakage.

[0005]

In order to achieve the above object, according to the present invention, a bottomed cylindrical protective frame, an inner pot accommodated in the protective frame, and a spiral winding around the bottom surface of the protective frame are provided. In an induction heating type rice cooker provided with a coil that is arranged to rotate and induction-heats the inner pan, and a ferrite attached below the coil, the ferrite is wound around the coil in a radial direction of 20%. Degrees or less, preferably 5 to 2
The ferrite is tilted in a range of 0 degrees, and one end of the ferrite is tilted in a state of extending above the coil surface at the center of the coil winding.

According to this structure, the induction coupling at the winding center of the coil is increased, the magnetic flux density supplied to the bottom surface of the inner pot is increased, and not only the induction heating is effectively performed, but also the magnetic field in the magnetic field is reduced. The space occupied by the ferrite can be increased.

[0007]

[0008]

[0009]

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

FIG. 1 is a sectional view of an induction heating rice cooker according to the present invention. This induction heating type rice cooker is generally provided with a bottomed cylindrical protective frame 2 in an exterior body 1, accommodates an inner pot 3 in the protective frame 2 so that it can be taken out, and covers an upper opening with a lid body 4. It can be opened and closed.

The exterior body 1 has a bottomed cylindrical shape in which a bottom body 1b is fitted into a lower opening of a body 1a, is made of a synthetic resin material, and has a shoulder extending inward at an upper opening edge. A part 5 is formed.

The protective frame 2 has a bottomed cylindrical shape, and an induction heating coil 7 is disposed on the bottom surface of the protective frame 2 in which a recess 6 is formed in the center of the bottom surface from the bottom surface side. As the induction heating coil 7, a coil formed by bundling a plurality of conductive wires and coating with an insulating material is sequentially wound around the inner and outer circumferences from a predetermined radial position toward the outer circumference.

A plurality of ferrites 8 (five in this embodiment, one less than the conventional one) are arranged below the induction heating coil 7. The ferrite 8 is held by a holding member 9 screwed to the bottom surface of the protection frame 2. Each of the ferrites 8 extends from the winding center of the induction heating coil 7 toward the outer periphery, and extends in the radial direction (the induction heating coil 7).
At a predetermined angle A with respect to the normal direction of the
Mounted at an angle in the range of degrees. In the present embodiment, the angle is 10 degrees, but this angle can be easily changed before screwing. Further, the preferred inclination direction is upstream with respect to the winding direction of the induction heating coil 7 (the direction from the center toward the outer peripheral side). That is, as shown in FIG. 4, the induction heating coil 7 is spirally wound from the center side toward the outer diameter side, so that the induction heating coil 7 gradually moves in the downstream direction with respect to the concentric circle indicated by the two-dot chain line. It spreads to the outer diameter side. For this reason, in the normal direction of the wound induction heating coil 7, the outer diameter side is actually inclined upstream with respect to the radial direction. Therefore, by inclining the ferrite 8 toward the upstream direction, even if the inclination angle with respect to the normal direction is increased, the inclination angle with respect to the actual normal direction can be suppressed. That is, the size of the ferrite 8 can be increased. Thereby, the induction heating coil 7
, The volume occupied by the ferrite 8 in the magnetic field generated by energizing the ferrite 8 can be increased, and a stable inductive coupling state can be maintained even if the number of ferrites 8 is reduced as compared with the conventional case. .

The ferrite 8 has an extension 8a at the center end thereof, which is bent toward the recess 6 of the protective frame 2 and extends above the coil surface B. This allows
The magnetic flux generated from the induction heating coil 7 can be supplied to the inner pot 3 accurately. The coil surface B means a contact surface below the wound induction heating coil 7 as shown in FIG.

The inner pot 3 is made of a magnetic material and has a cylindrical shape with a bottom. A flange 10 is formed in an upper opening of the inner pot 3 so that the inner pot 3 is placed on the shoulder 5 of the protective frame 2. ing.

In the induction-heated rice cooker having the above-described structure, a magnetic flux is generated by energizing the induction heating coil 7, and this magnetic flux is prevented from leaking downward by the ferrite 8. In this case, since the ferrite 8 is inclined with respect to the normal direction of the induction heating coil 7, the volume occupied in the magnetic field increases, and the magnetic flux leakage is prevented accurately. Moreover, since the ferrite 8 has the extending portion 8a extending upward at the center of the winding of the induction heating coil 7, the magnetic flux density for the inner pot 3 is increased. Therefore, the inner pot 3 can be efficiently induction-heated in combination with the increase in the volume occupied by the ferrite 8 in the magnetic field, and accurate induction heating can be maintained even when the number of ferrites 8 is reduced. It is possible.

In the above embodiment, the ferrite 8
Are attached to the protection frame 2 by the corresponding holding members 9, respectively.
May be held together.

[0018]

As is apparent from the above description, according to the induction heating type rice cooker according to the present invention, one end of the ferrite extends at the center of the coil and above the coil surface. As a result, inductive coupling can be effectively increased. Therefore, the same effect can be obtained even if the number of ferrites is reduced as compared with the related art, and the cost can be reduced.

Further, since the ferrite is wound so as to be inclined at an angle of 20 degrees or less with respect to the radial direction of the coil, the volume occupied by the ferrite in the magnetic field generated from the coil can be increased. . This makes it possible to realize appropriate induction heating of the inner pot with a small number, in combination with the effect of the bent portion of the ferrite.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an induction heating rice cooker according to the present invention.

FIG. 2 is an enlarged view showing a coil surface of FIG.

FIG. 3 is a bottom view of FIG. 1;

FIG. 4 is an enlarged view showing an inclination direction of the ferrite of FIG.

[Explanation of symbols]

 2 Protective frame 3 Inner pan 7 Induction heating coil 8 Ferrite

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A47J 27/00 H05B 6/12

Claims (1)

(57) [Claims] 1. A bottomed cylindrical protective frame, an inner pot accommodated in the protective frame, and a coil wound around the bottom surface of the protective frame in a spiral manner for induction heating the inner pan. An induction heating rice cooker comprising: a ferrite mounted below the coil;
Incline in the range of 0 degrees or less, one end of the ferrite,
An induction-heated rice cooker characterized by extending above the coil surface at the center of the coil winding.