JPH105122A - Electric rice cooker and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide an electric rice cooker having a coil base in which a heating coil capable of performing electromagnetic induction heating and having improved productivity and improved rice cooking performance is enclosed. SOLUTION: The inner pot 36 is detachably housed in a main body 30, and a coil base 33 in which a heating coil 37 for inductively heating the inner pot 36 is embedded. The heating coil 37 is provided with a thick portion provided so as to keep a substantially uniform gap between the bottom surface and the lower side surface of the heating coil 37 and expose the heating coil 37 on the back surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooker such as 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. 11, 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, in producing the storage section 6 in which the heating bottom coil 7, the heating body coil 8 and the heating band coil 9 of the electric rice cooker are enclosed, first, a molding die for the storage section 6 is formed. It is necessary to set each of the heating coils 7, 8, and 9 in such a case. At that time, the spiral heating coils 7, 8, and 9 are set in several places while maintaining the unstable shape, thereby increasing productivity. The heating section 7, 8, 9 is also displaced from the target position due to the pressure at the time of resin molding, etc.
The dimensions of the inner pot 4 and the heating coils 7, 8, 9 varied, and the inner pot 4 could not be heated uniformly, so that there was a problem that delicious rice could not be cooked.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a coil base having a heating coil for induction heating an inner pot removably housed in a main body. A thick portion is provided on the back surface, and the thick portion is provided with the heating coil while maintaining a substantially uniform gap between the bottom surface and the lower side surface of the inner pot and exposing the back surface thereof, and the heating coil is provided with the heating coil. The thickness on the heating coil is made thicker than the thickness of the other coil bases and is embedded in a non-metallic material.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 is a coil base provided with a heating coil for inductively heating an inner pan removably housed in a main body, wherein the coil base has a thick wall on its back surface. The thick portion is provided with the heating coil while maintaining a substantially uniform gap between the bottom surface and the lower side surface of the inner pot and exposing the back surface thereof, and the heating coil is provided on the heating coil. The exposed portion was formed outside the heating coil by making it thicker than the thickness of the other coil base and burying it in the non-metallic material, so that the outside of the heating coil was fitted along the molding die. While being formed in contact with each other, by setting the thickness of the coil base on the heating coil to be thicker than the other parts, the heating coil is less likely to hinder the flow of the resin during the coil base molding. Result Like heating coils lifted in Rubesu can be ensured reliably dimensional accuracy without destroying its shape,
Rice cooking performance can be improved.

According to a second aspect of the present invention, in a coil base molding die having a heating coil buried in the back surface and exposing the back surface of the heating coil, the heating coil is provided at least on the back surface of the standing wall of the coil base. The heating coil is embedded by providing an inclined surface on the inner peripheral standing wall of the concave portion of the molding die for embedding the heating coil, which guides the heating coil toward the back of the mold when the heating coil is mounted. An inclined surface that guides the heating coil in the depth direction of the mold is provided on the inner peripheral wall of the concave portion of the molding die to be heated. In this case, the coil base is positioned and buried, and the thickness of the coil base can be reliably ensured to improve safety.

According to a third aspect of the present invention, a heating coil for inductively heating an inner pot housed in the coil base is buried on the back surface of the coil base, and the coil base is provided substantially at the center of the coil base. A resin gate portion for molding is provided, and a plurality of magnetic shields are radially disposed on the back surface of the heating coil with the resin gate portion being substantially at the center, and the resin thickness of the magnetic shield and the heating coil is set at the upper surface of the heating coil. By setting the thickness of the resin between the magnetic shield and the heating coil to be equal to or less than the thickness of the upper surface of the heating coil, the upper surface of the heating coil is integrally formed when the heating coil is integrally formed. The flow of the resin is concentrated on the heating coil, and the floating of the heating coil can be prevented.

According to a fourth aspect of the present invention, a back surface of a heating coil for inductively heating an inner pot housed in the coil base is exposed and embedded on a back surface of the coil base, and a heating surface is provided on a back surface of the heating coil. By providing a plurality of radial ribs extending in the radial direction throughout the entire width of the coil and a plurality of inclined ribs not orthogonal to at least the radial ribs,
By providing a plurality of radial ribs and a plurality of inclined ribs that are not orthogonal to the radial ribs throughout the width of the heating coil on the back surface of the heating coil, it is possible to prevent the heating coil from floating due to repeated use. it can.

According to a fifth aspect of the present invention, a resin gate for molding the coil base is provided substantially at the center of the coil base, and the inner pot housed in the coil base is induction-heated on the back surface of the coil base. A film such as a synthetic resin is interposed between the synthetic resin forming the coil base and the heating coil embedded in the coil base while burying the coil, so that the synthetic resin forming the coil base and the coil By interposing a film such as a synthetic resin between the heating coil and the heating coil embedded in the base, the heating coil can be made free and its reliability can be further improved.

[0011]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below 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. Inside the main body 30, a protection frame body 32 made of a metal material and a coil base 33 are arranged to form a pot storage portion. The coil base 33 is formed of a heat-resistant material such as a synthetic resin into a bottomed cylindrical shape, and the upper end of the coil base 33 is fixed to the upper frame 31 via the protective frame body 32.
A heat retaining heater 35 is fixed to the protective frame body 32 with an aluminum tape.

An inner pot 36 is provided in the pot storage section 34, and 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. . 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.

In FIG. 2, the coil base 33 is formed with a substantially uniform gap from the inner pan 36, and a heating coil 37 is formed on the back surface thereof while maintaining a substantially uniform gap with the inner pan 36. It is buried to form a thick portion 33A.
The heating coil 37 bundles about 20 to 30 single wires of a self-fusing insulating coating having a diameter of 0.3 to 0.5 mm, and the bundled wires are opposed to the bottom surface and the lower side surface of the inner pot 36. An inner coil and an outer coil are formed respectively. That is, on the back surface of the coil base 33, a thick portion 33A is provided corresponding to the inner coil and the outer coil, and the thick portion 33A has a thickness 37t (for example, 3.5 mm) on the embedded heating coil 37.
The thickness 33t of the portion without the heating coil 37 (for example,
2.5mm).

The thick portion 33A of the coil base 33
In the figure, the heating coil 37 exposes its back surface from the thick portion 33A to provide an exposed portion 37A. This exposed part 37A
Is provided so that most of the back surface of the heating coil 37 is exposed, 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.

Reference numeral 40 denotes a temperature detecting device, which is vertically movable within a guide cylinder 41 integrally formed at the center bottom of the coil base 33 and whose upper end is pressed against the outer bottom surface of the inner pan 36. 42 is a circuit board for supplying power for generating an alternating magnetic field to the heating coil 37;
This is an operation board for operating 0. Reference numeral 44 denotes a synthetic resin outer lid, which is rotatably supported by a hinge at the rear of the upper frame 31.

The operation of the embodiment constructed as described above will be described. The object to be cooked is stored in the inner pot 36, and the upper frame 3
1 in a suspended state. After the outer lid 44 is closed, the operation is started by the operation board 43. Then, the circuit board 42 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.

That is, the position of the heating coil 37 with respect to the inner pot 36, which determines the quality of the rice cooking, is determined by the thickness 37t on the heating coil 37 and the thickness 33t of the other parts.
Since the thickness is set to be thicker, the flow of the molding resin guided by the thickness 33t at the time of integral molding of the coil base 33 causes the heating coil 3
7 does not hinder the flow of the molding resin, and most of the back surface of the heating coil 37 is in contact with the molding die of the coil base 33;
Numeral 7 is buried in a fixed position of the coil base 33, so that the rice cooking performance can be surely secured.

(Embodiment 2) A second embodiment of the present invention will be described with reference to FIGS. In FIG. 3, reference numeral 50 denotes a coil base formed of a non-metallic heat-resistant material such as a synthetic resin into a bottomed cylindrical shape, and accommodates the inner pot 51. A resin gate 54 for molding the coil base 50 is provided at a substantially central portion of the coil base 50 at a substantially upper end in a guide cylinder 53 of the temperature detecting device 52. On the back surface of the coil base 50, the heating coil 55 is embedded with an exposed portion 55A provided with most of its outer surface exposed. In FIG. 4, the heating coil 55 is opposed to the bottom of the inner pot 51 by a first thick portion (first concave portion of a molding die) 5 of the coil base 50.
0A, and a second thick portion 50B (a second concave portion of the molding die) provided on the back surface of the upright wall of the coil base 50 opposite to the side bottom surface of the inner pot 51. )
And an outer coil 55C having an arc-shaped cross section embedded in the outer coil 55C. On the end surface of the second thick portion 50B of the coil base 50 on the resin gate 54 side, an outer coil 55C of the heating coil 55 is provided with a second thickness which is a second concave portion of a molding die of the coil base 50. When setting and molding into the meat portion 50B, the inclined surface 50C which is set at an obtuse angle to the flow of the molding resin and which is inclined to a substantially vertical flow of the molding resin which is guided to the back of the molding die without obstructing the flow of the molding resin. Prepare.

A plurality of radial ribs 56 are provided outside the heating coil 55 so as to block the exposed portion 55A. A ferrite core 57, which is a high-permeability magnetic shield made of, for example, iron oxide as a main material, is embedded in the rib 56 with a uniform gap from the heating coil 55. 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, when the coil base 50 is integrally formed, the first recess 50A of the molding die of the coil base 50 is formed.
When the inner coil 55B and the outer coil 55C of the heating coil 55 are set in each of the second concave portion 50B, the outer coil 55C of the heating coil 55 is guided to the end face side of the second concave portion 50B on the resin gate 54 side. Slope 50
With the provision of C, the inclined surface is used as a guide by the resin molding pressure to be surely positioned and buried deep in the molding die, despite the fact that the positioning of the coil base 50 on the rear wall is difficult. It is.

(Embodiment 3) A third embodiment of the present invention will be described with reference to FIGS. In FIG. 5, reference numeral 60 denotes a coil base formed of a non-metallic heat-resistant material such as a synthetic resin into a bottomed cylindrical shape, and accommodates the inner pan 61. A resin gate 64 for molding the coil base 60 is provided at a substantially central portion of the coil base 60 at a substantially upper end in a guide cylinder 63 of the temperature detecting device 62. A heating coil 65 is embedded on the back surface of the coil base 60. The heating coil 65 is opposed to the bottom of the inner pan 61 by the coil base 6.
The inner coil 65A has a disc-shaped inner coil buried at the bottom of the inner pot 61 and an outer coil 65B having a circular arc cross section buried at the back of the standing wall facing the side bottom surface of the inner pot 61. The resin gate 64 is provided on the back surface of the heating coil 65 of the coil base 60.
A plurality of ribs 66 are integrally formed radially from the inner coil 65A of the heating coil 65 to the outer coil 65B. In FIG. 6, the rib 66 is formed so that at least the resin thickness 66 t between the inner coils 65 A is reduced by the resin thickness 60 t
A magnetic shield 67 described below is embedded. The configuration other than the coil base 60 is the same as that of the first embodiment, and will not be described.

With this configuration, when molding the coil base 60, the molding resin flowing from the resin gate 64 is such that the resin thickness 60 t on the upper surface of the heating coil 65 whose resin thickness is set to be large is between the inner coil 65 A of the rib 66. Resin thickness 66
It flows before t and presses the heating coil 65 to the molding die. Therefore, the heating coil 65 does not float from a fixed position, and can be reliably formed.

(Embodiment 4) A fourth embodiment of the present invention will be described with reference to FIGS. 7, reference numeral 70 denotes a coil base formed of a non-metallic heat-resistant material such as a synthetic resin into a bottomed cylindrical shape, and accommodates an inner pot 71. A heating coil 72 is embedded on the back surface of the coil base 70 so as to expose a part of the back surface. This heating coil 72
Is a disk-shaped inner coil 72A buried in the bottom of the coil base 70 opposite to the bottom of the inner pot 71;
The outer coil 72B has an arc-shaped cross section and is buried in the rear wall of the standing wall so as to face the bottom of the first side. In FIG. 8, the outer coil 72B of the heating coil 72
A plurality of radial ribs 70A extending in the radial direction throughout the entire width of B and at least a plurality of inclined ribs 70B not orthogonal to the radial ribs are provided integrally with the coil base 70. 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, the coil base 70 is provided with a plurality of radial ribs 70A and a plurality of inclined ribs 70B throughout the entire width of the back surface of the outer coil 72B of the heating coil 72. Can be prevented from floating due to plastic deformation during heating of the heating coil 72 made of a metal material such as copper, which has a much lower linear expansion coefficient than the synthetic resin constituting the above, and its reliability can be improved.

In this embodiment, a plurality of radial ribs 70 are provided.
Although A and the plurality of inclined ribs 70B are described as being provided only on the outer coil 72B, it is needless to say that the same effect can be obtained by providing the inner coil 72A.

(Embodiment 5) A fifth embodiment of the present invention will be described with reference to FIGS. In FIG. 9, 80
Is a coil base formed of a non-metallic heat-resistant material such as a synthetic resin into a bottomed cylindrical shape, and accommodates the inner pan 81. A resin gate 84 for molding the coil base 80 is provided substantially at the center of the coil base 80 at a substantially upper end inside the guide tube 83 of the temperature detecting device 82. The coil base 80
A heating coil 85 is buried in the back surface with a part of the back surface exposed. The heating coil 85 has a disc-shaped inner coil 85A buried in the bottom of the coil base 80 facing the bottom of the inner pot 81 and a back wall portion of the standing wall buried in a side bottom surface of the inner pot 81. The outer coil 85B has an arc-shaped cross section. In FIG. 10, between the synthetic resin forming the coil base 80, the heating coil embedded in the coil base 80, and the inner coil 85A and the outer coil 85B of the 85, the heating coil 82 is formed from the synthetic resin of the coil base 80. A film 86 of a synthetic resin or the like to be isolated is interposed.

In this embodiment, the film 86 has been described as being formed from the inner coil 82A of the heating coil 82 to the outer coil 82B, that is, covering substantially the entire back surface of the coil base 80. It goes without saying that even if it is a part of 82B, a corresponding effect can be obtained. The configuration other than the coil base 80 is the same as that of the first embodiment, and will not be described.

With this structure, a film 86 of synthetic resin or the like is interposed between the synthetic resin forming the coil base 80 and the heating coil 85 embedded in the coil base 80, so that the heating coil 85
Is free from the coil base 80 and the coil base 80
And the reliability of the heating coil 85 can be further improved.

[0029]

As described above, according to the first aspect of the present invention, in the coil base having the heating coil for induction heating the inner pan detachably housed in the main body, the coil base has A thick portion is provided on the back surface, and the thick portion is provided with the heating coil while maintaining a substantially uniform gap between the bottom surface and the lower side surface of the inner pot and exposing the back surface thereof, and the heating coil is provided with the heating coil. The thickness of the heating coil is made thicker than the thickness of the other coil bases and embedded in a non-metallic material to ensure the dimensional accuracy of the heating coil without losing its shape. Can be. As a result, rice cooking performance can be improved.

According to the second aspect of the present invention, in a coil base molding die having a heating coil embedded in the back surface and exposing the back surface of the heating coil, at least the standing wall of the coil base is formed. On the inner peripheral standing wall of the concave portion of the molding die for embedding the heating coil provided on the back surface, an inclined surface for guiding the heating coil toward the back of the die of the coil base at the time of mounting the heating coil is provided. Is provided with an inclined surface that guides the heating coil in the direction of the back surface of the coil base when the heating coil is placed, so that the inclined surface is used as a guide by the resin molding pressure to securely position the inner portion of the molding die. As a result, the thickness can be reliably ensured and safety can be improved.

According to the third aspect of the present invention, a heating coil for inductively heating an inner pot housed in the coil base is embedded on the back surface of the coil base, and substantially at the center of the coil base. A resin gate portion for molding of the coil base is provided, and a plurality of magnetic shields are radially arranged on the back surface of the heating coil with the resin gate portion being substantially at the center,
Since the thickness of the resin between the magnetic shield and the heating coil is set to be equal to or less than the thickness of the upper surface of the heating coil, it is possible to prevent the heating coil from floating when the heating coil is integrally formed.

According to the invention, the back surface of the heating coil for inductively heating the inner pot housed in the coil base is exposed and embedded on the back surface of the coil base, and the back surface of the heating coil is buried. By providing a plurality of radial ribs extending radially throughout the width of the heating coil and at least a plurality of inclined ribs not orthogonal to the radial rib, it is possible to prevent the heating coil from floating due to repeated use. it can.

According to the fifth aspect of the present invention, a molding resin gate for the coil base is provided substantially at the center of the coil base, and an inner pot accommodated in the coil base is provided on the back surface of the coil base. The reliability of the heating coil is further improved by embedding a heating coil for induction heating and interposing a film such as a synthetic resin between the synthetic resin forming the coil base and the heating coil embedded in the coil base. Can be improved.

[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 partial sectional view of the electric rice cooker.

FIG. 3 is a longitudinal sectional view of an electric rice cooker according to a second embodiment of the present invention.

FIG. 4 is a partial sectional view of the electric rice cooker.

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

FIG. 6 is a partial sectional view of the electric rice cooker.

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

FIG. 8 is a bottom view of the main part of the electric rice cooker.

FIG. 9 is a longitudinal sectional view of an electric rice cooker according to a fifth embodiment of the present invention.

FIG. 10 is a partial sectional view of the electric rice cooker.

FIG. 11 is a longitudinal sectional view of a conventional electric rice cooker.

[Explanation of symbols]

 30 Body 33 Coil base 33A Thick part 33t Thickness other than on heating coil 36 Inner pan 37 Heating coil 37A Exposed part 37t Thickness on heating coil 50A First thick part (first concave part of molding die) 50B Second thick portion (second concave portion of the molding die) 50C Inclined surface 53 Guide cylinder 54 Resin gate 55B Inner coil 55C Outer coil 66 Rib 66t Thickness between inner coil and magnetic shield 67 Magnetic shield 70A Radial rib 70B Inclined rib 86 film

Claims (5)

[Claims] An inner pot detachably stored in the main body,
A heating coil for inductively heating the inner pot, and a coil base for burying the heating coil, wherein the coil base maintains a substantially uniform gap with the bottom surface and the lower side surface of the inner pot,
And an electric rice cooker having a thick-walled portion exposing the heating coil on a back surface thereof. 2. The heating coil is provided on an inner peripheral vertical wall of a concave portion of a molding die for burying the heating coil provided on the back surface of the vertical wall of the coil base. The method for manufacturing an electric rice cooker according to claim 1, wherein the electric rice cooker is mounted on a surface. 3. A coil base is provided with a resin gate portion at a substantially central portion thereof, and a plurality of magnetic shields radially arranged on the back surface of the heating coil around the resin gate portion and the heating coil. The electric rice cooker according to claim 1, wherein the thickness of the resin is set to be equal to or less than the thickness of the upper surface of the heating coil. 4. The coil base according to claim 1, wherein a plurality of radial ribs extending in a radial direction are provided throughout the entire width of the heating coil, and a plurality of inclined ribs which are not orthogonal to at least the radial ribs. Electric rice cooker. 5. A coil base is provided with a resin gate portion at a substantially central portion thereof, and a film of a synthetic resin or the like is interposed between a synthetic resin forming the coil base and a heating coil embedded in the coil base. The electric rice cooker according to claim 1.