JP3120722B2 - Electric rice 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 rice cooker for heating an inner pot by an induction heating method.

[0002]

2. Description of the Related Art In recent years, an electric rice cooker utilizing electromagnetic induction heating has been proposed. This electric rice cooker is shown in FIG.
In FIG. 5, reference numeral 1 denotes a main body having an openable / closable lid 2 on an upper surface, and an inner pan 3 is detachably disposed inside the main body 1. The inside of the inner pot 3 is made of a magnetic material 4 such as iron or stainless steel, and the outside is made of a heat insulating material 5 such as wood. Reference numeral 6 denotes a storage portion for the inner pot 3. The storage portion 6 is formed of a molding material such as heat-resistant plastic, and a heating bottom coil 7 is provided at a portion of the storage portion 6 facing the bottom of the inner pot 3. And a helical heating body coil 8 is buried in a portion facing the side surface of the inner pot 3 to uniformly heat the side surface of the inner pot 3 of the magnetic material, and further provided on the inner pot 3. A helical heating zone coil 9 having the same shape as the heating cylinder coil 8 is embedded in a portion of the lid 2 facing the hanging side surface of the lid 2.

With the above configuration, the heating bottom coil 7,
The entire bottom and side surfaces of the inner pan 3 are uniformly heated by the heating body coil 8 and the heating band coil 9, and the food in the inner pan 3 is uniformly heated and cooked.

[0004]

However, when producing the storage section 6 in which the heating bottom coil 7, the heating body coil 8, and the heating zone coil 9 are enclosed, first, each of the molding dies of the storage section 6 is provided with a mold. It is necessary to set the heating coils 7, 8, 9; however, at that time, the spiral heating coils 7, 8, 9 are set while maintaining their unstable shapes at several places, resulting in poor productivity. , And the completed storage section 6
Each heating coil 7,
8 and 9 are sealed with the target position shifted, and the dimensions of the inner pot 4 and each of the heating coils 7, 8, and 9 vary, so that the inner pot 4 cannot be heated uniformly and delicious rice cannot be cooked. Had the problem that

[0005] In view of the above problems, an object of the present invention is to provide an electric rice cooker having excellent reliability and improved productivity.

[0006]

According to the present invention, there is provided an inner pot detachably housed in a main body, a heating coil for inductively heating the inner pot, and the heating coil embedded therein. A coil base integrally formed of a non-metallic material, wherein the coil base is provided with a plurality of exposed portions on a surface of the heating coil opposite to the inner pot, and a plurality of radial ribs are provided between the exposed portions. And the heating rib is attached to this radial rib.
A magnetic shielding body having a linear portion and an arc-shaped outer peripheral portion along the shape of the file is buried , and a resin component is formed at the upper end substantially at the center.
A gate for the shape is provided, and this gate is
The magnetic shield is disposed on the back surface of the coil base by
The magnetic body is provided with irregularities on the rear surface to engage with a molding die .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
This coil base is resin-molded on the upper end in the approximate center of the case.
A gate part is provided, and the coil part is
The heating coil is shaped radially on the back of the base.
A magnetic shield with a straight section along the circumference and an arc-shaped outer periphery is provided.
At the same time, the back side of this magnetic shield engages the molding die
The unevenness allows flow from the upper end of the coil base.
Press the magnetic shield against the back of the coil base with the applied resin pressure.
As well as engaging with the mold due to the irregularities on the back of the magnetic shield.
To secure the position of the magnetic shield and stabilize the rice cooking performance.
Can be.

According to a second aspect of the present invention, the thickness of the coil base between the inner coil and the outer coil on the upper part of the magnetic shield is provided by providing a thickness between the inner coil and the outer coil of the heating coil embedded in the coil base. Can be made uniform thickness,
The sink in molding the coil base can be eliminated, and the productivity can be increased.

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 30 denotes a main body, and an upper frame 31 is fitted into an upper opening of the main body 30. The main body 30
A pot housing portion 34 is formed by disposing a protective frame body 32 made of a metal material and a coil base 33 inside. The coil base 33 is formed of a heat-resistant material such as a synthetic resin into a cylindrical shape with a bottom.
2 and is fixed to the upper frame 31. This protective frame 3
2, a heat retaining heater 35 is fixed by an aluminum tape. As shown in FIG. 2, the inner pot 36 is formed of a high conductivity material such as aluminum and a clad material made of a magnetic metal material such as ferrite stainless steel on its outer surface. Have been. The inner pot 36 is detachably mounted by placing the flange 36A on the upper surface of the upper frame 31 in a suspended state, and a gap is formed between the coil base 33 and the outer bottom of the inner pot 36. It is formed.

2 and 3, a heating coil 37 is embedded in the coil base 33. The heating coil 37 bundles about 20 to 30 strands of a self-fusing insulating coating material having a diameter of 0.3 to 0.5 mm, and faces the bundled wire to the bottom surface and the lower side surface of the inner pot 36. The inner coil and the outer coil are respectively formed. The heating coil 37 has an exposed portion 3 on the back surface of the coil base 33.
7A, the exposed portion 37A is provided so as to expose most of the back surface of the heating coil 37, and a plurality of radial ribs 38 are provided so as to block the exposed portion 37A. A ferrite core 39, which is a high-permeability magnetic shield made of, for example, iron oxide as a main material, is embedded in the rib 38 below the heating coil 37 and with a uniform gap from the heating coil 37. 40 is the coil base 33
A motor base integrally formed with the
1 is placed.

Reference numeral 42 denotes a temperature detecting device, which is supported by a sensor base 44 so as to be able to move up and down in a guide tube 43 integrally formed on the outer bottom of the coil base 33, and has an upper end outside the inner pot 36. Crimping on the bottom. Reference numeral 45 denotes a circuit board through which a current for generating an alternating magnetic field is applied to the heating coil 37. Reference numeral 46 denotes a board base which is fitted to the main body 30 and the upper frame 31 and is connected to the circuit board 45 and the operation board 4.
7 is fixed. 48 is an outer cover made of synthetic resin,
1 is rotatably supported by a hinge at the rear.

The operation of the present embodiment configured as described above will be described. The object to be cooked is stored in the inner pot 36 and placed on the upper surface of the upper frame 31 in a suspended state. And the outer lid 48
, The operation is started by the operation board 47. Then, the circuit board 45 operates to supply a current to the heating coil 37. Then, an alternating magnetic field is generated in the heating coil 37, whereby the inner pot 36 is heated and the object to be cooked is cooked.
At this time, most of the heating coil 37 is provided as an exposed portion 37A from the back surface of the coil base 33. Therefore, at the time of molding the coil base 33, the outer surface of the heating coil 37 almost comes into contact with the molding die,
As a result, the heating coil 37, whose shape is difficult to determine, is buried in the coil base 33 without being deformed, so that the dimensional accuracy can be reliably ensured, and the rice cooking performance can also be reliably ensured. Here, the heating coil 37 generates heat when energized. Naturally, the coefficient of thermal expansion of the heating coil 37 (metal such as copper) is higher than that of the coil base 33 (synthetic resin). However, since the plurality of radial ribs 38 are arranged between the exposed portions 37A on the back surface of the heating coil 37, the heating coil 37 is prevented from floating from the coil base 33. be able to. In the present embodiment, a plurality of radial ribs 38 arranged below the heating coil 37 are provided.
In the above description, the structure in which the ferrite core 39 is embedded is described. However, it is needless to say that the same effect can be obtained by providing a rib in which the ferrite core 39 is not embedded.

Second Embodiment A second embodiment of the present invention will be described with reference to FIG. In FIG. 4, reference numeral 50 denotes a bottomed coil base formed of a nonmetallic heat-resistant material such as a synthetic resin.
A heating coil 51 composed of a disk-shaped inner coil 51A and an outer coil 51B having an arc-shaped cross section is embedded in the coil base 50 so that most of its outer surface is exposed. A plurality of radial ribs 52 are provided outside the heating coil 51 so as to block the exposed surface. A ferrite core 53, which is a high-permeability material magnetic shield made of, for example, iron oxide as a main raw material, is embedded in the rib 52 with a uniform gap from the heating coil 51. The inner coil 51A of the heating coil 51
A coil base 50 between the inner coil 51A and the outer coil 51B is provided between the inner coil 51A and the outer coil 51B.
A ring-shaped groove 54 in which the thickness of the synthetic resin from the ferrite core 53 is substantially uniform is provided. The configuration other than the coil base 50 is the same as that of the first embodiment, and a description thereof will be omitted.

With this configuration, the coil base 50 can make the thickness of the ferrite core 53 between the inner coil 51A and the outer coil 51B of the heating coil 51 uniform with other portions,
It is provided as a carp 37A. Therefore, when the coil base 33 is formed, most of the outer surface of the heating coil 37 comes into contact with the molding die. As a result, the heating coil 37, whose shape is difficult to determine, is buried in the coil base 33 without being deformed, and the dimensional accuracy is assured. And the rice cooking performance can be surely secured. Here, the heating coil 37 generates heat when energized. Naturally, the coefficient of thermal expansion of the heating coil 37 (metal such as copper) is higher than that of the coil base 33 (synthetic resin). However, since a plurality of radial ribs are disposed between the exposed portions 37A on the back surface of the heating coil 37, the coil base 3
The lifting of the heating coil 37 from the position 3 can be prevented. In the present embodiment, the ferrite core 39 is provided on all the radial ribs arranged below the heating coil 37.
However, it is needless to say that the same effect can be obtained by providing a rib in which the ferrite core 39 is not embedded.

Third Embodiment A third embodiment of the present invention will be described with reference to FIG. In FIG. 4, reference numeral 50 denotes a bottomed coil base formed of a nonmetallic heat-resistant material such as a synthetic resin.
In this coil base 50, a heating coil 51 composed of a disk-shaped inner coil 51A and an outer coil 51B having an arc-shaped cross section is embedded. A plurality of radial ribs 52 are provided outside the heating coil 51. A ferrite core 53, which is a high-permeability material magnetic shield made of, for example, iron oxide as a main raw material, is embedded in the rib 52 with a uniform gap from the heating coil 51. The inner coil 5 of the heating coil 51
The coil base 50 between the outer coil 1A and the outer coil 51B has a ring shape in which the thickness of the synthetic resin from the inner coil 51A, the outer coil 51B, and the ferrite core 53 is substantially uniformly removed from the inner surface of the coil base 50. Groove 54 is provided. The configuration other than the coil base 50 is the same as that of the first embodiment, and a description thereof will be omitted.

With this configuration, the coil base 50 can make the thickness of the ferrite core 53 between the inner coil 51A and the outer coil 51B of the heating coil 51 uniform with other portions,
The sink and the like at the time of resin molding of the coil base 50 can be eliminated, and the productivity can be improved. Further, in this type of coil base 50 in which the heating coil 51 is embedded and formed of a synthetic resin material, cracks are generated due to repeated thermal shocks for many years of use. When falling into the base 50, the short circuit between the heating coil 51 and the inner pot 36 causes an electric shock. However, in the second embodiment, water droplets dropped into the coil base 50 are discharged from the inner coil 51A of the heating coil 51. It flows into the ring-shaped groove 54 between the outer coil 51B and the outer coil 51B, that is, without the heating coil 51, and its safety is also maintained.

(Embodiment 4) A fourth embodiment of the present invention will be described with reference to FIG. In FIG. 5, reference numeral 60 denotes a coil base formed in a bottomed cylindrical shape from a nonmetallic heat-resistant material such as a synthetic resin.
A disc-shaped inner coil 61 is provided on the back surface of the coil base 60.
A and a heating coil 6 comprising an outer coil 61B having an arc-shaped cross section
1 is provided. Outside the heating coil 61. For example, a plurality of ferrite cores 62, which are magnetic shields of a high magnetic permeability sintered using iron oxide as a main material, are provided radially with a uniform gap from the heating coil 61. Further, a protrusion 62A is provided between the inner coil 61A and the outer coil 61B of the heating coil 61 of the ferrite core 62. Other configurations are the same as those of the first embodiment, and a description thereof will be omitted.

With this configuration, a new magnetic flux flows to both ends of the ferrite core 62 via the convex portion 62A between the inner coil 61A and the outer coil 61B of the heating coil 61 of the plurality of ferrite cores 62 arranged radially. It can be formed to enhance the heating effect and improve rice cooking performance.

Embodiment 5 A fifth embodiment of the present invention will be described with reference to FIG. In FIG. 6, reference numeral 70 denotes a coil base formed in a cylindrical shape with a bottom by using a heat-resistant material such as a synthetic resin. The coil base 70 includes a heating element including a disc-shaped inner coil 71A and an outer coil 71B having a circular cross section. The coil 71 is embedded. A plurality of radial ribs 72 are provided outside the heating coil 71. A ferrite core 73, which is a high-permeability magnetic shield made of, for example, iron oxide as a main material, is embedded in the rib 72 with a uniform gap from the heating coil 71. A projection 73A is integrally provided on the upper surface of the ferrite core 73 located between the inner coil 71A and the outer coil 71B of the heating coil 71. The configuration other than the coil base 70 is the same as that of the first embodiment, and a description thereof will be omitted.

With this configuration, as in the third embodiment, the ferrite core 73 is provided with a plurality of radially arranged ferrite cores 73 via the protrusions 73A between the inner coil 71A and the outer coil 71B of the heating coil 71. A new flow of magnetic flux is formed at both ends of the core 73 to enhance the heating effect and improve rice cooking performance. Further, the heating coil 7 is formed integrally with the coil base 70.
The thickness of the coil base 70 between the inner coil 71A and the outer coil 71B can be made uniform with other portions without providing a shape change such as a concave portion. As a result, the material can be reduced and the productivity can be improved. Can be enhanced.

Embodiment 6 A sixth embodiment of the present invention will be described with reference to FIG. In FIG. 7, reference numeral 80 denotes a coil base formed in a cylindrical shape with a bottom by using a heat-resistant material such as a synthetic resin, and a gate portion 80A from which a film-shaped gate for resin-forming the coil base 80 is cut off at substantially the center. Prepare. A heating coil 81 including a disc-shaped inner coil 81A and an outer coil 81B having an arc-shaped cross section is embedded in the coil base 80. Outside the heating coil 81, the heating coil 8
A ferrite core 82 is provided extending from the inner coil 81A to the outer coil 81B and a plurality of ferrite cores 82 are arranged radially about the gate 80A. A protrusion 82A is provided between the inner coil 81A and the outer coil 81B of the heating coil 81 of the ferrite core 82, and the upper end of the protrusion 82A is connected to the upper end of the inner coil 81A of the heating coil 81 and the outer coil 81B. Are provided on the extended straight line at the upper end. The ferrite core 82 is provided with the heating coil 8.
1 is buried in a rib 83 provided radially on the outer surface.

With this configuration, when the coil base 80 is molded, the resin radially flowing from the gate portion 80A quickly flows into the entire coil base 80 via the radial ribs 83 on which a plurality of ferrite cores 82 are arranged, Inner coil 8 of heating coil 81 of core 82
The upper end of the projection 82A provided between the outer coil 1B and the outer coil 81B is
By providing the upper end of the inner coil 81A of the heating coil 81 and the upper end of the outer coil 81B on a straight line and integrally molding the coil base 80, the protrusions 82 of the ferrite 82 are formed.
The flow of the resin is rectified by A, and the exposure of the heating coil 81 to the upper surface of the coil base 80 can be prevented.

Embodiment 7 Further, a seventh embodiment of the present invention will be described with reference to FIG. In FIG. 3, as described above, reference numeral 33 denotes a coil base formed in a cylindrical shape with a bottom by a heat-resistant material such as a synthetic resin. At substantially the center of the coil base 33, the coil base 33 is cut into a film gate for resin molding. A gate 33A is provided. The coil base 33 has a disk-shaped inner coil 3.
7B and a heating coil 37 composed of an outer coil 37C having an arc-shaped cross section are embedded. Outside the heating coil 37, the inner coil 37B of the heating coil 37 and the outer coil 37C
And a plurality of ferrite cores 39 extending radially from the gate portion 33A substantially at the center and provided together with the heating coil 37. The gate portion 3 of the coil base 33 on the back surface of the ferrite core 39
A first protrusion 39A is provided on the 3A side, and a second protrusion 39B is provided substantially at the center of the back surface.

With this configuration, at the time of molding the coil base 33, the ferrite core 39 is pressed against the back surface of the coil base 33 by the resin pressure radially flowing from the gate portion 33 A, and the first ferrite core 39 provided on the back surface of the ferrite core 39 is formed.
The second projections 39A and 39B engage with the molding die to secure the positioning of the ferrite core and stabilize the rice cooking performance.

[0025]

As described above, according to the first aspect of the present invention , protection is achieved by the resin pressure flowing from the upper end of the coil base.
While pressing the magnetic body against the back of the coil base,
The unevenness of the back surface of the body is engaged with the mold, ensuring the magnetic shielding member
Positioning can stabilize rice cooking performance.

According to the second aspect of the present invention, the heating coil including the inner coil and the outer coil embedded in the coil base, and the coil base between the inner coil and the outer coil of the heating coil, The ring is provided with a groove from the inner surface of the base and a ring-shaped groove is provided.When water such as water level drops by mistake on the coil base, the water drops flow into the ring-shaped groove without the heating coil. That is, even if a crack occurs in the coil base, its safety is maintained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electric rice cooker according to a first embodiment of the present invention.

FIG. 2 is a rear view of the electric rice cooker.

FIG. 3 is a partial sectional view of the electric rice cooker.

FIG. 4 is a partial longitudinal sectional view of the electric rice cooker according to the second and third embodiments of the present invention.

FIG. 5 is a partial longitudinal sectional view of an electric rice cooker according to a fourth embodiment of the present invention.

FIG. 6 is a partial longitudinal sectional view of an electric rice cooker according to a fifth embodiment of the present invention.

FIG. 7 is a partial longitudinal sectional view of an electric rice cooker according to a sixth embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of a conventional electric rice cooker.

[Explanation of symbols]

 Reference Signs List 30 main body 33 coil base 33A gate portion 36 inner pot 37 heating coil 37A exposed portion 37B inner coil 37C outer coil 38 rib 39 ferrite core 39A first convex portion 39B second convex portion 54 ring-shaped groove

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masato Sano 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-7-67765 (JP, A) JP-A-61- 71581 (JP, A) JP-A-5-317176 (JP, A) JP-A-4-284389 (JP, A) JP-A-3-145106 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) A47J 27/00

Claims (2)

(57) [Claims] An inner pot detachably stored in the main body,
A heating coil for induction heating this inner pot, and a coil base embedded with the heating coil and integrally formed of a non-metallic material, wherein the coil base is provided on a surface of the heating coil opposite to the inner pot with a plurality of coils. the exposure unit is provided, a plurality of radial ribs provided between the exposed portion, the heating to the radial rib
As well as embedded <br/> magnetic-shield member having a straight portion along the shape of the coil and arc-shaped outer peripheral portion, the resin in the upper end portion of the substantially center
A gate part for molding is provided, and this gate part is
Then, the magnetic shield is disposed on the back surface of the coil base, and
An electric rice cooker having a concave and a convex provided on a back surface of a magnetic shield to engage with a molding die . 2. The heating coil has an inner coil and an outer coil, and the coil base is provided with a ring-shaped groove between the inner coil and the outer coil by robbing the inner surface.
An electric rice cooker as described.